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  • 51.
    Mohamed, Alaa
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics. Cairo University, Egypt.
    Nasser, W. S.
    Osman, T. A.
    Toprak, Muhammet
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Muhammed, Mamoun
    KTH, School of Engineering Sciences (SCI), Applied Physics. Alexandria University, Egypt.
    Uheida, Abdusalam
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Removal of chromium (VI) from aqueous solutions using surface modified composite nanofibers2017In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 505, p. 682-691Article in journal (Refereed)
    Abstract [en]

    A novel material composite nanofibers (PAN-CNT/TiO2-NH2) based on adsorption of Cr(VI) ions, was applied. Polyacrylonitrile (PAN) and carbon nanotube (CNTs)/titanium dioxide nanoparticles (TiO2) functionalized with amine groups (TiO2-NH2) composite nanofibers have been fabricated by electrospinning. The nanostructures and the formation process mechanism of the obtained PAN-CNT/TiO2-NH2 composite nanofibers are investigated using FTIR, XRD, XPS, SEM, and TEM. The composite nanofibers were used as a novel adsorbent for removing toxic chromium Cr(VI) in aqueous solution. The kinetic study, adsorption isotherm, pH effect, initial concentration, and thermodynamic study were investigated in batch experiments. The composite nanofibers had a positive effect on the absorption of Cr(VI) ions under neutral and acidic conditions, and the saturated adsorption reached the highest when pH was 2. The adsorption equilibrium reached within 30 and 180 min with an initial solution concentration increasing from 10 to 300 mg/L, and the process can be better described using nonlinear pseudo first than nonlinear pseudo second order model and Intra-particle diffusion. Isotherm data fitted well using linear and nonlinear Langmuir, Freundlich, Redlich-Peterson, and Temkin isotherm adsorption model. Thermodynamic study showed that the adsorption process is exothermic. The adsorption capacity can remain up to 80% after 5 times usage, which show good durability performance. The adsorption mechanism was also studied by UV-vis and XPS.

  • 52.
    Mohamed, Alaa
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics. Akhbar El Yom Academy, Egypt.
    Osman, T. A.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Yilmaz, E.
    Uheida, Abdusalam
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Visible light photocatalytic reduction of Cr(VI) by surface modified CNT/titanium dioxide composites nanofibers2016In: Journal of Molecular Catalysis A: Chemical, ISSN 1381-1169, E-ISSN 1873-314X, Vol. 424, p. 45-53Article in journal (Refereed)
    Abstract [en]

    In this work we report a highly efficient photocatalytic reduction of Cr(VI) based on PAN-CNT/TiO2-NH2 composite nanofibers fabricated by using electrospinning technique followed by chemical crosslinking of surface modified TiO2 NPs functionalized with amino group. The structure and morphology of the fabricated composite nanofibers were characterized by FTIR, SEM, TEM, TGA, and XPS. The results indicate that the composite nanofibers possess excellent photoreduction performance for Cr(VI) under visible light (125 W) after 30 min, which is much faster than previous reports. The effects of various experimental parameters such as catalyst dose, irradiation time, initial concentration of Cr(VI), and pH on the photoreduction efficiency of Cr(VI) were investigated. The highest photoreduction efficiency of Cr (VI) was obtained at low acidity and low amount of TiO2/CNT photocatalyst. The kinetic experimental data was attained and fitted well with a pseudo-first-order model. The UV–vis spectrophotometer and XPS analyses proved that chromate Cr(VI) was reduced to Cr(III). In addition, it can be concluded that the addition of the phenol enhances the photocatalytic reduction of Cr(VI). Furthermore, the photoreduction mechanism has also been discussed. Finally, the fabricated composite nanofibers were found to be stable after at least five regeneration cycles.

  • 53. Mohamed, Alaa
    et al.
    Osman, T. A.
    Toprak, Muhammet Sadaka
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Uheida, Abdusalam
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Surface functionalized composite nanofibers for efficient removal of arsenic from aqueous solutions2017In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 180, p. 108-116Article in journal (Refereed)
    Abstract [en]

    A novel composites nanofiber was synthesized based on PAN-CNT/TiO2-NH2 nanofibers using electrospinning technique followed by chemical modification of TiO2 NPs. PAN-CNT/TiO2-NH2 nanofiber were characterized by XRD, FTIR, SEM, and TEM. The effects of various experimental parameters such as initial concentration, contact time, and solution pH on As removal were investigated. The maximum adsorption capacity at pH 2 for As(III) and As(V) is 251 mg/g and 249 mg/g, respectively, which is much higher than most of the reported adsorbents. The adsorption equilibrium reached within 20 and 60 min as the initial solution concentration increased from 10 to 100 mg/L, and the data fitted well using the linear and nonlinear pseudo first and second order model. Isotherm data fitted well to the linear and nonlinear Langmuir, Freundlich, and Redlich-Peterson isotherm adsorption model. Desorption results showed that the adsorption capacity can remain up to 70% after 5 times usage. This work provides a simple and an efficient method for removing arsenic from aqueous solution.

  • 54.
    Mohamed, Alaaeldin
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics. Cairo University, Egypt; Akhbar El Yom Academy, Egypt.
    Yousef, S.
    Ali Abdelnaby, M.
    Osman, T. A.
    Hamawandi, Bejan
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics. Alexandria University, Egypt.
    Uheida, Abdusalam
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Photocatalytic degradation of organic dyes and enhanced mechanical properties of PAN/CNTs composite nanofibers2017In: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 182, p. 219-223Article in journal (Refereed)
    Abstract [en]

    This work describes the enhanced mechanical properties of the composite nanofibers and the photodegradation of two organic dyes using PAN/CNTs under UV irradiation at different volume concentration (0.05, 0.1, 0.2, and 0.3 wt.%). The composite nanofibers was performed with polyacrylonitrile (PAN), and carbon nanotubes (CNTs) by electrospinning process. The composite nanofibers structure and morphology is characterized by XRD, FTIR, SEM, and TEM. The result indicates that with increasing CNTs content, the mechanical properties of the composite nanofibers was enhanced, and became more elastic, and the elastic modulus increased drastically. The results of mechanical properties exhibit improvements in tensile strengths, and elastic modulus by 38% and 84% respectively, at only 0.05 wt.% CNTs. Moreover, photocatalytic degradation performance in short time and low power intensity was achieved comparison to earlier reports.

  • 55. Monteiro-Riviere, N. A.
    et al.
    Inman, A. O.
    Mathur, S.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Fadeel, B.
    Riviere, J. E.
    Effects of eight nanoparticles of different sizes and shapes on human epidermal keratinocytes2012In: Journal of Investigative Dermatology, ISSN 0022-202X, E-ISSN 1523-1747, Vol. 132, p. S52-S52Article in journal (Other academic)
  • 56. Morillo, D.
    et al.
    Uheida, Abdusalam
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Perez, G.
    Muhammed, Mamoun Ali
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Valiente, M.
    Arsenate removal with 3-mercaptopropanoic acid-coated superparamagnetic iron oxide nanoparticles2015In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 438, p. 227-234Article in journal (Refereed)
    Abstract [en]

    In the present work, superparamagnetic iron oxide nanoparticles (SPION) surface-coated with 3-merca-ptopropanoic acid (3-MPA) were prepared and their feasibility for the removal of arsenate from dilute aqueous solutions was demonstrated. The synthesized 3-MPA-coated SPION was characterized using transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and Fourier transform infra-red spectrometry (FTIR). Separation efficiency of the coated nanoparticles and the equilibrium isotherm of arsenate adsorption were investigated. The obtained results reveal the arsenate adsorption to be highly pH-dependent, and the maximum adsorption was attained in less than 60 min. The resulting increase of 3-MPA-coated SPION adsorption capacity to twice the adsorption capacity of SPION alone under the same conditions is attributed to the increase of active adsorption sites. An adsorption reaction is proposed. On the other hand, efficient recovery of arsenate from the loaded nanoparticles was achieved using nitric acid (HNO3) solution, which also provides a concentration over the original arsenate solution.

  • 57.
    Morteza, Ghanbarpourgeravi
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Nader, Nikkam
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Khodabandeh, Rahmatollah
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Toprak, Mohammet S
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Muhammed, Mamoun Ali
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Thermal performance of screen mesh heat pipe with Al2O3 nanofluid2015In: Experimental Thermal and Fluid Science, ISSN 0894-1777, E-ISSN 1879-2286, Vol. 66, p. 213-220Article in journal (Refereed)
    Abstract [en]

    This study presents the effect of Al2O3 nanofluid (NF) on thermal performance of screen mesh heat pipe in cooling applications. Three cylindrical copper heat pipes of 200 mm length and 6.35 mm outer diameter containing two layers of screen mesh were fabricated and tested with distilled water and water based Al2O3 NF with mass concentrations of 5% and 10% as working fluids. To study the effect of NF on the heat pipes thermal performance, the heat input is increased and then decreased consecutively and the heat pipes surface temperatures are measured at steady state conditions. Results show that using 5 wt.% of Al2O3 NF improves the thermal performance of the heat pipe for increasing and decreasing heat fluxes compared with distilled water, while utilizing 10 wt.% of Al2O3 NF deteriorates the heat pipe thermal performance. For heat pipe with 5 wt.% Al2O3 NF the reduction in thermal resistance of the heat pipe is found to be between 6% and 24% for increasing and between 20% and 55% for decreasing heat fluxes, while the thermal resistance increased between 187% and 206% for increasing and between 155% and 175% for decreasing steps in heat pipe with 10 wt.% of Al2O3 NF.

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  • 58.
    Motahar, Sadegh
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. Department of Mechanical Engineering, Isfahan University of Technology, Iran.
    Nikkam, Nader
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Alemrajabi, Ali A.
    Khodabandeh, Rahmatollah
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    A novel phase change material containing mesoporous silica nanoparticles for thermal storage: A study on thermal conductivity and viscosity2014In: International Communications in Heat and Mass Transfer, ISSN 0735-1933, E-ISSN 1879-0178, Vol. 56, p. 114-120Article in journal (Refereed)
    Abstract [en]

    In this research, mesoporous silica (MPSiO2) nanoparticles were dispersed in n-octadecane as an organic phase change material (PCM) in order to produce a novel composite for thermal storage. Stable PCMs containing 1 wt.%, 3 wt.% and 5 wt.% MPSiO2 nanopartides (PCM/MPSiO2) were fabricated by dispersing MPSiO2 in PCM. MPSiO2 particles were investigated by SEM and TEM techniques, which showed high order of porosity and spherical particles of ca. 300 nm. The thermal conductivity in both solid and liquid phases was measured by transient plane source (TPS) technique in the temperature range of 5-55 degrees C. A maximum thermal conductivity enhancement of 5% for 3 wt.% MPSiO2 at 5 degrees C, and 6% for 5 wt.% MPSiO2 at 55 degrees C was experimentally obtained. Moreover, it was observed that enhancement in thermal conductivity is non-monotonic in solid phase with increasing MPSiO2 particle loading. The viscosity results showed that for mass fractions of nanoparticles greater than 3% in liquid PCM, the behavior of liquid is non-Newtonian. Also, the viscosity of PCM containing MPSiO2 nanopartides was measured to be increased up to 60% compared to the liquid PCM for 5 wt% MPSiO2 at 35 degrees C.

  • 59. Motahar, Sadegh
    et al.
    Nikkam, Nader
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Alemrajabi, Ali A.
    Khodabandeh, Rahmatollah
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Experimental investigation on thermal and rheological properties of n-octadecane with dispersed TiO2 nanoparticles2014In: International Communications in Heat and Mass Transfer, ISSN 0735-1933, E-ISSN 1879-0178, Vol. 59, p. 68-74Article in journal (Refereed)
    Abstract [en]

    In the present study, titanium (IV) oxide (TiO2) nanoparticles were dispersed in n-octadecane to fabricate phase change material (PCM) with enhanced properties and behavior. Thermal conductivity (TC) and viscosity of n-octadecane/TiO2 dispersions were experimentally investigated using transient plane source (TPS) technique and rotating coaxial cylindrical viscometer, respectively. The results showed that the TC of n-octadecane/TiO2 dispersion depends on temperature and nanoparticle loading. A non-monotonic behavior of TC enhancement in both solid and liquid phases was observed. In solid phase, the maximum TC enhancement occurred at 3 wt.% of nanoparticles. When the nanoparticle mass fraction was over 4% in liquid phase, the TC started to decrease. The rheological behavior of the n-octadecane/TiO2 samples indicated that dispersions with low nanoparticle mass fractions demonstrate Newtonian behavior, and for higher mass factions the shear-thinning behavior was observed. Shear stress vs. shear rate curves showed that the liquid phase of PCM behaves like a Bingham plastic fluid for mass fraction greater than 1%. As expected, the effective viscosity could be influenced by temperature. At the shear rate of 48.92 s(-1) for 3 wt.% nanoparticles, the effective viscosity decreased by 26.8% while temperature increased from 35 degrees C to 55 degrees C. For the investigated n-octadecane/TiO2 dispersions, new thermophysical correlations are proposed for predicting TC and rheological properties.

  • 60.
    Muhammed, Mamoun
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Nikkam, Nader
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Toprak, Muhammet
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    The use of a suspension comprising mesoporous silica particles as heat exchange fluids: Användningen av en suspension omfattande mesoporösa kiseldioxidartiklar som värmeväxlarvätska2010Patent (Other (popular science, discussion, etc.))
  • 61. Murray, Ashley R.
    et al.
    Kisin, Elena
    Inman, Alfred
    Young, Shih-Houng
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Burks, Terrance
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Uheida, Abdusalam
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Tkach, Alexey
    Waltz, Micah
    Castranova, Vincent
    Fadeel, Bengt
    Kagan, Valerian E.
    Riviere, Jim E.
    Monteiro-Riviere, Nancy
    Shvedova, Anna A.
    Oxidative Stress and Dermal Toxicity of Iron Oxide Nanoparticles In Vitro2013In: Cell Biochemistry and Biophysics, ISSN 1085-9195, E-ISSN 1559-0283, Vol. 67, no 2, p. 461-476Article in journal (Refereed)
    Abstract [en]

    A number of commercially available metal/metal oxide nanoparticles (NPs) such as superparamagnetic iron oxide (SPION) are utilized by the medical field for a wide variety of applications. These NPs may able to induce dermal toxicity via their physical nature and reactive surface properties. We hypothesize that SPION may be toxic to skin via the ability of particles to be internalized and thereby initiate oxidative stress, inducing redox-sensitive transcription factors affecting/leading to inflammation. Due to the skin's susceptibility to UV radiation, it is also of importance to address the combined effect of UVB and NPs co-exposure. To test this hypothesis, the effects of dextran-coated SPION of different sizes (15-50 nm) and manufacturers (MicroMod, Rostock-Warnemunde, Germany and KTH-Royal Institute of Technology, Stockholm, Sweden) were evaluated in two cell lines: normal human epidermal keratinocytes (HEK) and murine epidermal cells (JB6 P+). HEK cells exposed to 20 nm (KTH and MicroMod) had a decrease in viability, while the 15 and 50 nm particles were not cytotoxic. HEK cells were also capable of internalizing the KTH particles (15 and 20 nm) but not the MicroMod SPION (20 and 50 nm). IL-8 and IL-6 were also elevated in HEK cells following exposure to SPION. Exposure of JB6 P+ cells to all SPIONs evaluated resulted in activation of AP-1. Exposure to SPION alone was not sufficient to induce NF-kappa B activation; however, co-exposure with UVB resulted in significant NF-kappa B induction in cells exposed to 15 and 20 nm KTH SPION and 50 nm MicroMod particles. Pre-exposure of JB6 P+ cells to UVB followed by NPs induced a significant depletion of glutathione, release of cytokines, and cell damage as assessed by release of lactate dehydrogenase. Altogether, these data indicate that co-exposure to UVB and SPIONs was associated with induction of oxidative stress and release of inflammatory mediators. These results verify the need to thoroughly evaluate the adverse effects of UVB when evaluating dermal toxicity of engineered NPs on skin.

  • 62.
    Najmoddin, Najmeh
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Beitollahi, Ali
    Devlin, Eamonn
    Kavas, Huseyin
    Mohseni, Seyed Majid
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Åkerman, Johan
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Niarchos, Dimitris
    Rezaie, Hamidreza
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Magnetic properties of crystalline mesoporous Zn-substituted copper ferrite synthesized under nanoconfinement in silica matrix2014In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 190, p. 346-355Article in journal (Refereed)
    Abstract [en]

    A series of ordered mesoporous single phase Cu1-xZnxFe2O4 spinel ferrites, with x ranging from 0.00 to 0.75 with a step increment of 0.25, are prepared by a novel nanocasting route with the aid of vinyl-functionalized mesoporous silica as a hard template. All samples display a relatively high surface area and narrow pore size distribution from nitrogen sorption analysis. The magnetic hysteresis loops of these samples measured at 300 K, the temperature dependence of the zero field cooled (ZFC) and field cooled (FC) magnetization curves and the Mossbauer Spectra show the presence of superparamagnetic nanopartides in all samples. The hysteresis data indicate that the maximum saturation magnetization of 52 emu g(-1), is obtained for the composition with x = 0.25. For x >= 0.5, the saturation magnetization decreases as a result of the cation redistribution within tetrahedral (A) and octahedral (B) sites which weakens the A-B interactions due to triangular Yafet-Kittel spin arrangement on the B-sublattice. The observed magnetic features are attributed to the confined spaces of the host material which acts as a nanoreactor, limiting the growth of the embedded oxide phase and significantly influencing the cation distribution of copper-zinc ferrite on the A and B sites.

  • 63.
    Najmoddin, Najmeh
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Beitollahi, Ali
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Ansari, Narges
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Devlin, Eamonn
    Mohseni, Seyed Majid
    KTH, School of Information and Communication Technology (ICT), Material Physics, Material Physics, MF.
    Rezaie, Hamidreza
    Niarchos, Dimitris
    Åkerman, Johan
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Effect of nanoconfinement on the formation, structural transition and magnetic behavior of mesoporous copper ferrite2014In: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 598, p. 191-197Article in journal (Refereed)
    Abstract [en]

    Superparamagnetic, cubic single phase, ordered mesoporous copper ferrite is synthesized through confinement in nanocages of mesoporous silica. The heat generated during the reaction is conserved in the silica template pore channels, which allows the formation of copper ferrite at a relatively low processing temperature. The Jahn-Teller distortion is suppressed due to the effect of nanoconfinement and thus the high temperature phase of cubic copper ferrite is stabilized at room temperature. The particle size obtained from TEM, the crystallite size calculated from XRD and the magnetic domain size estimated from magnetization measurements are all in good agreement, manifesting the significant role of the confinement in the growth and fabrication of crystalline, single magnetic domain, nanoparticles with superparamagnetic behavior at room temperature.

  • 64.
    Nikkam, Nader
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Bitaraf Haghigh, Ehsan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Saleemi, Mohsin
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Behi, Mohammadreza
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Khodabandeh, Rahmatollah
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Palm, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Experimental study on preparation and base liquid effect on thermo-physical and heat transport characteristics of α-SiC nanofluids2014In: International Communications in Heat and Mass Transfer, ISSN 0735-1933, E-ISSN 1879-0178, Vol. 55, p. 38-44Article in journal (Refereed)
    Abstract [en]

    Nanostructured solid particles dispersed in a base liquid are a new class of nano-engineeredcolloidal solutions, defined with a coined name of nanofluids (NFs). These fluids have shownpotential to enhance heat transfer characteristics of conventional base liquids utilized in heattransfer application. We recently reported on the fabrication and thermo-physical propertyevaluation of SiC NFs systems, containing SiC particles with different crystal structure. In thisstudy, our aim is to investigate the heat transfer characteristics of a particular α-SiC NF withrespect to the effect of α-SiC particle concentration and different base liquids on the thermophysicalproperties of NFs. For this purpose, a series of NFs with various α-SiC NPsconcentration of 3, 6 and 9wt% were prepared in different base liquids of distilled water (DW)and distilled water/ethylene glycol mixture (DW/EG). Their thermal conductivity (TC) andviscosity were evaluated at 20 oC. NF with DW/EG base liquid and 9wt% SiC NPs loadingexhibited the best combination of thermo-physical properties, which was therefore selected forheat transfer coefficient (HTC) evaluation. Finally, HTC tests were performed and compared indifferent criteria, including equal Reynolds number, equal mass flow rate and equal pumpingpower for a laminar flow regime. The results showed HTC enhancement of NF over the baseliquid for all evaluation criteria; 13% at equal Reynolds number, 8.5% at equal volume flow and5.5% at equal pumping power. Our findings are among the few studies in the literature where theheat transfer enhancement for the NFs over its base liquid is noticeable and based on a realistic situation.

  • 65.
    Nikkam, Nader
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Ghanbarpour, Morteza
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Saleemi, Mohsin
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Haghighi, Ehsan Bitaraf
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Khodabandeh, Rahmatollah
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Palm, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Experimental investigation on thermo-physical properties of copper/diethylene glycol nanofluids fabricated via microwave-assisted route2014In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 65, no 1-2, p. 158-165Article in journal (Refereed)
    Abstract [en]

    This study investigates the fabrication, thermal conductivity and rheological characteristics evaluation of nanofluids consisting of copper nanoparticles in diethylene glycol base liquid. The fabricated Cu nanofluids displayed enhanced thermal conductivity over the base liquid. Copper nanoparticles were directly formed in diethylene glycol using microwave-assisted heating, which provides uniform heating of reagents and solvent, accelerating the nucleation of metal clusters, resulting in monodispersed nanostructures. Copper nanoparticles displayed an average primary particle size of 75 ± 25 nm from SEM micrographs, yet aggregated to form large spherical particles of about 300 nm. The physicochemical properties including thermal conductivity and viscosity of nanofluids were measured for the nanofluids with nanoparticle concentration between 0.4 wt% and 1.6 in the temperature range of 20-50 C. Proper theoretical correlations/models were applied to compare the experimental results with the estimated values for thermal conductivity and viscosity of nanofluids. For all cases, thermal conductivity enhancement was higher than the increase in viscosity showing the potential of nanofluids to be utilized as coolant in heat transfer applications. A thermal conductivity enhancement of ∼7.2% was obtained for nanofluids with 1.6 wt% nanoparticles while maximum increase in viscosity of ∼5.2% was observed for the same nanofluid.

  • 66.
    Nikkam, Nader
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Ghanbarpour, Morteza
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Saleemi, Mohsin
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Khodabandeh, Rahmatollah
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Thermal and rheological properties of micro- and nanofluids of copper in diethylene glycol: as heat exchange liquid2013In: Nanoscale Thermoelectric Materials: Thermal and Electrical Transport, and Applications to Solid-state Cooling and Power Generation, Cambridge: Cambridge Scholars Publishing, 2013, , p. 6p. 165-170Conference paper (Refereed)
    Abstract [en]

    This study reports on the fabrication of nanofluids/microfluids (NFs/MFs) with experimental and theoretical investigation of thermal conductivity (TC) and viscosity of diethylene glycol (DEO) base NFs/MFs containing copper nanoparticles (Cu NPs) and copper microparticles (Cu MPs). For this purpose, Cu NPs (20-40 nm) and Cu MPs (0.5-1.5 urn) were dispersed in DEG with particle loading between 1 wt% and 3 wt%. Ultrasonic agitation was used for dispersion and preparation of stable NFs/MFs, and thus the use of surfactants was avoided. The objectives were investigation of impact of size of Cu particle and concentration on TC and viscosity of NFs/MFs on DEG as the model base liquid. The physicochemical properties of all particles and fluids were characterized by using various techniques including Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM) and Dynamic Light Scattering (DLS) techniques. Fourier Transform Infrared Spectroscopy (FTIR) analysis was performed to study particles' surfaces. NFs and MFs exhibited a higher TC than the base liquid, while NFs outperformed MFs showing a potential for their use in heat exchange applications. The TC and viscosity of NFs and MFs were presented, along with a comparison with values from predictive models. While Maxwell model was good at predicting the TC of MFs, it underestimated the TC of NFs, revealing that the model is not directly applicable to the NF systems.

  • 67.
    Nikkam, Nader
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Saleemi, Mohsin
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Bitaraf Haghighi, Ehsan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Ghanbarpour, Morteza
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Toprak, Muhammet
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Khodabandeh, Rahmatollah
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Palm, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Design and Fabrication of Efficient Nanofluids Based on SiC Nanoparticles for Heat Exchange Applications2013Conference paper (Other academic)
  • 68.
    Nikkam, Nader
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Saleemi, Mohsin
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Haghighi, Ehsan Bitaraf
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Ghanbarpour, Morteza
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Khodabandeh, Rahmatollah
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Palm, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Fabrication, Characterization and Thermo-physical Property Evaluation of SiCNanofluids for Heat Transfer Applications2014In: Nano-Micro Letters, ISSN 2150-5551, Vol. 6, no 2, p. 178-189Article in journal (Refereed)
    Abstract [en]

    Nanofluids (NFs) are nanotechnology-based colloidal suspensions fabricated by suspending nanoparticles (NPs) in a base liquid. These fluids have shown potential to improve the heat transfer properties of conventional heat transfer fluids. In this study we report in detail on the fabrication, characterization and thermo-physical property evaluation of SiC NFs, prepared using SiC NPs with different crystal structure, for heat transfer applications.  For this purpose, a series of SiC NFs containing SiC NPs with different crystal structure (α-SiC and β-SiC) were fabricated in a water (W)/ethylene glycol (EG) mixture (50/50 wt % ratio). Physicochemical properties of NPs/NFs were characterized by using various techniques such as powder X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR), Dynamic Light Scattering (DLS) and Zeta Potential Analysis were performed. Thermo-physical properties including thermal conductivity (TC) and viscosity for NFs containing SiC particles (α- and β- phase) were measured. The results showed among all suspensions, NF fabricated with α-SiC particles have more favorable thermo-physical properties compared to the NFs fabricated with β-SiC; the observed difference was attributed to combination of several factors, including crystal structure (β- vs. α-), sample purity, and residual chemicals exhibited on SiC nanoparticles. A TC enhancement of ~20% while 14% increased viscosity were obtained for a NF containing 9wt% of particular type of α-SiC NPs indicating promising capability of these kind of NFs for further heat transfer characteristics investigations. 

  • 69.
    Nikkam, Nader
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Saleemi, Mohsin
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Li, Shangua
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Toprak, Muhammet
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Bitaraf Haghighi, Ehsan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Khodabandeh, Rahmatollah
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Palm, Björn E
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Novel Nanofluids Based on Mesoporous Silica for Enhanced Heat Transfer2011In: Journal of nanoparticle research, ISSN 1388-0764, E-ISSN 1572-896X, Vol. 13, no 11, p. 6201-6206Article in journal (Refereed)
    Abstract [en]

    Nanofluids, which are liquids with engineered nanometer-sized particles suspensions, have drawn remarkable attraction from the researchers because of their enormous potential to enhance the efficiency in heat-transfer fluids. In the present study, water-based calcined mesoporous silica nanofluids were prepared and characterized. The commercial mesoporous silica (MPSiO2) nanoparticles were dispersed in deionized water by means of pH adjustment and ultrasonic agitation. MPSiO2 nanoparticles were observed to have an average particle size of 350 ± 100 nm by SEM analysis. The concentration of MPSiO2 was varied between 1 and 6 wt%. The physicochemical properties of nanofluids were characterized using various techniques, such as particle size analyzer, zeta-potential meter, TEM, and FT-IR. The thermal conductivity was measured by Transient Plane Source (TPS) method, and nanofluids showed a higher thermal conductivity than the base liquid for all the tested concentrations.

  • 70.
    Nikkam, Nader
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Saleemi, Mohsin
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Toprak, M.S.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Singh, S.P.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Effect of nanoparticle morphology on thermal conductivity and rheology of Zinc Oxide nanofluids2012Conference paper (Refereed)
    Abstract [en]

    Nanofluids are stable dispersions of engineered nanometer-sized particles which have shown potential to enhance heat transfer properties. Nanoparticle morphology might influence the heat transport properties of the nanofluid. In this work our aim is to investigate the influence of nanoparticle morphology in the heat transfer and rheological properties of  ZnO nanofluids. ZnO nanoparticles and nanorods were synthesized and dispersed in ethylene glycol, as the base fluid, to obtain nanofluids with different percentages of nanoparticle loading. Ultrasonic agitation was used for obtaining a stable suspension and the use of surfactants was avoided. The concentrations of ZnO nanofluids were varied between 1 wt% and 3 wt%. The physicochemical properties of nanofluids were characterized by using various techniques including particle size analyzer, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FT-IR). The thermal conductivity of prepared nanofluids were measured by Transient Hot Wire (THW) method and our finding on the physicochemical, transport and rheological properties of the ZnO nanofluids, containing nanoparticles with different morphology, are presented in detail.

  • 71.
    Nikkam, Nader
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Saleemi, Mohsin
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Toprak, Muhammet
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Nano-engineered SiC Heat Transfer Fluids for Effective Cooling2013Conference paper (Refereed)
  • 72.
    Nikkam, Nader
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Saleemi, Mohsin
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Toprak, Muhammet
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Bitaraf Haghighi, Ehsan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Khodabandeh, Rahmatollah
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Palm, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Microwave-assisted Synthesis of Copper Nanofluids for Heat Transfer Applications2011Conference paper (Refereed)
  • 73.
    Nikkam, Nader
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Saleemi, Mohsin
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Toprak, Muhammet
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Haghighi, E.B.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Khodabandeh, R.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Palm, B,
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Rheological Properties of Copper Nanofluids Synthesised by Using Microwave-Assisted Method2012In: Proceedings of the 4th International Conference on Nanostructures (ICNS4), 2012, p. 1555-1557Conference paper (Refereed)
  • 74.
    Nikkam, Nader
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Singh, Sathya Prakash
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Saleemi, Mohsin
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Toprak, Muhammet
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    A comparative study of rheological properties and thermal conductivity of silver nanofluids in water and ethylene glycol base fluids2012Conference paper (Refereed)
  • 75.
    Okoli, Chuka
    et al.
    KTH, School of Biotechnology (BIO), Environmental Microbiology. KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Fornara, Andrea
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Qin, Jian
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Dalhammar, Gunnel
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Rajarao, Gunaratna
    KTH, School of Biotechnology (BIO), Environmental Microbiology.
    Characterization of Superparamagnetic Iron Oxide Nanoparticles and Its Application in Protein Purification2011In: Journal of Nanoscience and Nanotechnology, ISSN 1533-4880, E-ISSN 1533-4899, Vol. 11, no 11, p. 10201-10206Article in journal (Refereed)
    Abstract [en]

    The application of surface modified magnetic adsorbent particles in combination with magnetic separation techniques has received considerable awareness in recent years. There is a particular need in protein purification and analysis for specific, functional and generic methods of protein binding on solid supports. Nanoscale superparamagnetic iron oxide particles have been used to purify a natural coagulant protein extracted from Moringa oleiferaseeds. Spectrophotometric analysis of the coagulant protein was performed using synthetic clay solution as substrate. Protein binding with carboxyl and silica surface modified superparamagnetic iron oxide nanoparticles (SPION) were compared with the known carboxyl methyl cellulose (CMC) beads of ∼1 m. SPION modified with carboxyl surface showed higher binding capacity towards the coagulant protein compared to the CMC beads. The high surface area to volume ratio of the carboxyl-coated SPION resulted in high binding capacity and rapid adsorption kinetics of the crude protein extract. The purification and molecular weight of coagulant protein is analyzed by SDS-PAGE. This approach utilizes the most efficient, feasible and economical method of coagulant protein purification and it can also be applicable to other proteins that possess similar properties.

  • 76. Rieth, M.
    et al.
    Boutard, J. L.
    Dudarev, S. L.
    Ahlgren, T.
    Antusch, S.
    Baluc, N.
    Barthe, M. -F
    Becquart, C. S.
    Ciupinski, L.
    Correia, J. B.
    Domain, C.
    Fikar, J.
    Fortuna, E.
    Fu, C. -C
    Gaganidze, E.
    Galan, T. L.
    Garcia-Rosales, C.
    Gludovatz, B.
    Greuner, H.
    Heinola, K.
    Holstein, N.
    Juslin, N.
    Koch, F.
    Krauss, W.
    Kurzydlowski, K. J.
    Linke, J.
    Linsmeier, Ch.
    Luzginova, N.
    Maier, H.
    Martinez, M. S.
    Missiaen, J. M.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Munoz, A.
    Muzyk, M.
    Nordlund, K.
    Nguyen-Manh, D.
    Norajitra, P.
    Opschoor, J.
    Pintsuk, G.
    Pippan, R.
    Ritz, G.
    Romaner, L.
    Rupp, D.
    Schaeublin, R.
    Schlosser, J.
    Uytdenhouwen, I.
    van der Laan, J. G.
    Veleva, L.
    Ventelon, L.
    Wahlberg, S.
    Willaime, F.
    Wurster, S.
    Yar, M. A.
    Review on the EFDA programme on tungsten materials technology and science2011In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 417, no 1-3, p. 463-467Article in journal (Refereed)
    Abstract [en]

    All the recent DEMO design studies for helium cooled divertors utilize tungsten materials and alloys, mainly due to their high temperature strength, good thermal conductivity, low erosion, and comparably low activation under neutron irradiation. The long-term objective of the EFDA fusion materials programme is to develop structural as well as armor materials in combination with the necessary production and fabrication technologies for future divertor concepts. The programmatic roadmap is structured into four engineering research lines which comprise fabrication process development, structural material development, armor material optimization, and irradiation performance testing, which are complemented by a fundamental research programme on "Materials Science and Modeling". This paper presents the current research status of the EFDA experimental and testing investigations, and gives a detailed overview of the latest results on fabrication, joining, high heat flux testing, plasticity, modeling, and validation experiments.

  • 77. Rieth, M.
    et al.
    Dudarev, S. L.
    Gonzalez De Vicente, S. M.
    Aktaa, J.
    Ahlgren, T.
    Antusch, S.
    Armstrong, D. E. J.
    Balden, M.
    Baluc, N.
    Barthe, M. -F
    Basuki, W. W.
    Battabyal, M.
    Becquart, C. S.
    Blagoeva, D.
    Boldyryeva, H.
    Brinkmann, J.
    Celino, M.
    Ciupinski, L.
    Correia, J. B.
    De Backer, A.
    Domain, C.
    Gaganidze, E.
    Garcia-Rosales, C.
    Gibson, J.
    Gilbert, M. R.
    Giusepponi, S.
    Gludovatz, B.
    Greuner, H.
    Heinola, K.
    Höschen, T.
    Hoffmann, A.
    Holstein, N.
    Koch, F.
    Krauss, W.
    Li, H.
    Lindig, S.
    Linke, J.
    Linsmeier, C.
    Lopez-Ruiz, P.
    Maier, H.
    Matejicek, J.
    Mishra, T. P.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Munoz, A.
    Muzyk, M.
    Nordlund, K.
    Nguyen-Manh, D.
    Opschoor, J.
    Ordas, N.
    Palacios, T.
    Pintsuk, G.
    Pippan, R.
    Reiser, J.
    Riesch, J.
    Roberts, S. G.
    Romaner, L.
    Rosiński, M.
    Sanchez, M.
    Schulmeyer, W.
    Traxler, H.
    Urena, A.
    Van Der Laan, J. G.
    Veleva, L.
    Wahlberg, Sverker
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Walter, M.
    Weber, T.
    Weitkamp, T.
    Wurster, S.
    Yar, Mazher Ahmed
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    You, J. H.
    Zivelonghi, A.
    A brief summary of the progress on the EFDA tungsten materials program2013In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 442, no 1-3, p. S173-S180Article in journal (Refereed)
    Abstract [en]

    The long-term objective of the European Fusion Development Agreement (EFDA) fusion materials programme is to develop structural and armor materials in combination with the necessary production and fabrication technologies for reactor concepts beyond the International Thermonuclear Experimental Reactor. The programmatic roadmap is structured into four engineering research lines which comprise fabrication process development, structural material development, armor material optimization, and irradiation performance testing, which are complemented by a fundamental research programme on "Materials Science and Modeling." This paper presents the current research status of the EFDA experimental and testing investigations, and gives a detailed overview of the latest results on materials research, fabrication, joining, high heat flux testing, plasticity studies, modeling, and validation experiments.

  • 78. Rieth, M.
    et al.
    Dudarev, S. L.
    Gonzalez De Vicente, S. M.
    Aktaa, J.
    Ahlgren, T.
    Antusch, S.
    Armstrong, D. E. J.
    Balden, M.
    Baluc, N.
    Barthe, M. -F
    Basuki, W. W.
    Battabyal, M.
    Becquart, C. S.
    Blagoeva, D.
    Boldyryeva, H.
    Brinkmann, J.
    Celino, M.
    Ciupinski, L.
    Correia, J. B.
    De Backer, A.
    Domain, C.
    Gaganidze, E.
    García-Rosales, C.
    Gibson, J.
    Gilbert, M. R.
    Giusepponi, S.
    Gludovatz, B.
    Greuner, H.
    Heinola, K.
    Höschen, T.
    Hoffmann, A.
    Holstein, N.
    Koch, F.
    Krauss, W.
    Li, H.
    Lindig, S.
    Linke, J.
    Linsmeier, C.
    López-Ruiz, P.
    Maier, H.
    Matejicek, J.
    Mishra, T. P.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Muñoz, A.
    Muzyk, M.
    Nordlund, K.
    Nguyen-Manh, D.
    Opschoor, J.
    Ordás, N.
    Palacios, T.
    Pintsuk, G.
    Pippan, R.
    Reiser, J.
    Riesch, J.
    Roberts, S. G.
    Romaner, L.
    Rosiński, M.
    Sanchez, M.
    Schulmeyer, W.
    Traxler, H.
    Ureña, A.
    Van Der Laan, J. G.
    Veleva, L.
    Wahlberg, Sverker
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Walter, M.
    Weber, T.
    Weitkamp, T.
    Wurster, S.
    Yar, Mazher Ahmed
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    You, J. H.
    Zivelonghi, A.
    Recent progress in research on tungsten materials for nuclear fusion applications in Europe2013In: Journal of Nuclear Materials, ISSN 0022-3115, E-ISSN 1873-4820, Vol. 432, no 1-3, p. 482-500Article, review/survey (Refereed)
    Abstract [en]

    The current magnetic confinement nuclear fusion power reactor concepts going beyond ITER are based on assumptions about the availability of materials with extreme mechanical, heat, and neutron load capacity. In Europe, the development of such structural and armour materials together with the necessary production, machining, and fabrication technologies is pursued within the EFDA long-term fusion materials programme. This paper reviews the progress of work within the programme in the area of tungsten and tungsten alloys. Results, conclusions, and future projections are summarized for each of the programme's main subtopics, which are: (1) fabrication, (2) structural W materials, (3) W armour materials, and (4) materials science and modelling. It gives a detailed overview of the latest results on materials research, fabrication processes, joining options, high heat flux testing, plasticity studies, modelling, and validation experiments.

  • 79.
    Saleemi, Mohsin
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Famengo, A.
    Fiameni, S.
    Boldrini, S.
    Battiston, S.
    Johnsson, M.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Thermoelectric performance of higher manganese silicide nanocomposites2015In: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 619, p. 31-37Article in journal (Refereed)
    Abstract [en]

    Higher manganese silicides (HMS) are proven to be promising candidates as p-type thermoelectric material in the temperature range of 400-700 K. In this work, a series of nanostructured (NS) bulk MnSi1.73 with different levels of Ytterbium inclusions were fabricated via ball milling and the solid state reaction was completed by spark plasma sintering (SPS). Nanopowders and SPS consolidated Yb-HMS nanocomposites (NC) were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) to reveal the crystal structure and morphology respectively. High resolution transmission electron microscopy (HRTEM) coupled with energy dispersive X-ray spectroscopy (EDS) was used to investigate the material composition in bulk grains. Yb was observed to stay as nanoinclusions at the grain boundaries. TE transport properties, including Seebeck coefficient, electrical resistivity, and thermal diffusivity as well as charge carrier concentrations were evaluated. Thermal conductivity decreased with increasing Yb content, while the electrical conductivity improved for the highest Yb content. A highest figure of merit (ZT) of 0.42 at 600 degrees C was achieved for 1% Yb-HMS NC sample.

  • 80.
    Saleemi, Mohsin
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Nikkam, Nader
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Ghadami Yazdi, Milad
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Toprak, Muhammet
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Effect of particles size and surface modification on thermal conductivity and viscosity of alumina nanofluids2013Conference paper (Refereed)
    Abstract [en]

    Electronics industry growing faster and it demands ultrahigh performance cooling systems to manage the heat loses in terms of energy and money. Conventional cooling fluids are approaching to its limit due to the poor thermal transport performance and a new era for the heat transfer fluids had been initiated about two decades ago. When nanoparticles dispersed in conventional heat transfer fluid (like water, oil, glycols), the mixture is called as nanofluids. Alumina suspensions are well known class of nanofluids, which have been investigated in many recent studies to determine the non-classical behavior of the suspensions. The aim of this study is to investigate optimized particle size and suitable surface modification for the improved dispersion properties of nanofluids with enhanced thermal performance and low viscosity. We have utilized two different types of alumina crystal phases; one is Boehmite (γ-AlOOH) and clay type (α -Al2O3) and the nanofluids were prepare d by suspending different size of nanoparticles in water and water/ethylene glycol (EG) mixtures. Dynamic light scattering (DLS) was used to determine the agglomerate size and scanning electron microscope (SEM) used to study the particle size and morphology. Zeta potential was measured to determine the electrostatic stability for the dispersed nanoparticles. Thermal conductivity was estimated by using KD2 Pro setup and up to 10 % enhancement in TC was observed as compared to the base fluid. Viscosity was measured by capillary viscometer, which shows the significant effect from the addition of additives and surfactants. Possible mechanisms contributing in reducing the viscosity and increasing the thermal conductivity are described in details.

  • 81.
    Saleemi, Mohsin
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Nikkam, Nader
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Muhammad, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Toprak, Muhammet
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Aging, Thermal Cycling and Stability Studies for Nanofluids2015In: Aging, Thermal Cycling and Stability Studies for Nanofluids, 2015Conference paper (Refereed)
    Abstract [en]

    Stability of nanofluids is one of the critical assessments for the efficient systems that the solid content of nanofluid should be stable and well dispersed for longer time. Production of a homogenous dispersion is real technical challenge due to strong van der Waals attraction among the nanoparticles, which preferring the formation of aggregates. Stable nanofluids can be achieved via recommended physical and chemical treatments such as addition of additives and surfactants, surface-active agents to disperse hydrophobic materials, adjusting the pH value to provide electrochemical stability.Detailed investigations were carried out to identify the stability parameters, dispersion methods, application requirements, experimental investigation to determine the stability of nanofluids. Aluminum oxide (Al2O3), titanium oxide (TiO2) and cerium oxide (CeO2) were selected for these studies. Custom designed stability measurement setup was used to record the sedimentation rate. Aging test was performed in the heat transfer coefficient (HTC) setup to determine the erosion and corrosion properties. Thermal cycling was performed up to 80 oC with maximum heating cycles of 500 times. Dynamic light scattering (DLS) used to estimate the aggregate size before and after the thermal cycling and aging test. Results from the time depended DLS measurements, sedimentation rate and aging effects presents that Al2O3 nanofluids have better performance.

  • 82. Saleemi, Mohsin
    et al.
    Ruditskiy, A.
    Toprak, Muhammet
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Stingaciu, M.
    Johnsson, M.
    Kretzschmar, I.
    Jacquot, A.
    Jaegle, M.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Evaluation of the Structure and Transport Properties of Nanostructured Antimony Telluride (Sb2Te3)2014In: Journal of Electronic Materials, ISSN 0361-5235, E-ISSN 1543-186X, Vol. 43, no 6, p. 1927-1932Article in journal (Refereed)
    Abstract [en]

    Antimony telluride, (Sb2Te3), and its doped derivatives are considered to be among the best p-type thermoelectric (TE) materials for room temperature (300-400 K) applications. However, it is still desirable to develop rapid and economical routes for large-scale synthesis of Sb2Te3 nanostructures. We report herein a high yield, simple and easily scalable synthetic method for polycrystalline Sb2Te3 nanostructures. Prepared samples were compacted into dense pellets by use of spark plasma sintering. The products were characterized by x-ray diffraction and scanning electron microscopy. To investigate the anisotropic behavior of Sb2Te3 TE transport property measurements were performed along and perpendicular to the direction of compaction. Thermal conductivity, electrical conductivity, and Seebeck coefficient measurement over the temperature range 350-525 K showed that the anisotropy of the material had a large effect on TE performance.

  • 83.
    Saleemi, Mohsin
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Toprak, Muhammet
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Li, Shanghua
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Ma, Ying
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Wang, Xiaodi
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Nikkam, Nader
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Haghighi, Ehsan Bitaraf
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Khodabandeh, Rahmatollah
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Palm, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Ceria Nanofluids for Efficient Heat Management2010Conference paper (Refereed)
  • 84.
    Saleemi, Mohsin
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Fiameni, S.
    Boldrini, S.
    Battiston, S.
    Famengo, A.
    Stingaciu, M.
    Johnsson, M.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Spark plasma sintering and thermoelectric evaluation of nanocrystalline magnesium silicide (Mg2Si)2013In: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 48, no 5, p. 1940-1946Article in journal (Refereed)
    Abstract [en]

    Recently magnesium silicide (Mg2Si) has received great interest from thermoelectric (TE) society because of its non-toxicity, environmental friendliness, comparatively high abundance, and low production material cost as compared to other TE systems. It also exhibited promising transport properties, including high electrical conductivity and low thermal conductivity, which improved the overall TE performance (ZT). In this work, Mg2Si powder was obtained through high energy ball milling under inert atmosphere, starting from commercial magnesium silicide pieces (99.99 %, Alfa Aesar). To maintain fine microstructure of the powder, spark plasma sintering (SPS) process has been used for consolidation. The Mg2Si powder was filled in a graphite die to perform SPS and the influence of process parameters as temperature, heating rate, holding time and applied pressure on the microstructure, and densification of compacts were studied in detail. The aim of this study is to optimize SPS consolidation parameters for Mg2Si powder to achieve high density of compacts while maintaining the nanostructure. X-Ray diffraction (XRD) was utilized to investigate the crystalline phase of compacted samples and scanning and transmission electron microscopy (SEM & TEM) coupled with Energy-Dispersive X-ray Analysis (EDX) was used to evaluate the detailed microstructural and chemical composition, respectively. All sintered samples showed compaction density up to 98 %. Temperature dependent TE characteristics of SPS compacted Mg2Si as thermal conductivity, electrical resistivity, and Seebeck coefficient were measured over the temperature range of RT 600 A degrees C for samples processed at 750 A degrees C, reaching a final ZT of 0.14 at 600 A degrees C.

  • 85.
    Saleemi, Mohsin
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Li, Shanghua
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Johnsson, Mats
    Arrhenius Laboratory, Stockholm University.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Fabrication and Spark Plasma Sintering of Nanostructured Bismuth Telluride (Bi2Te3)2012In: 9Th European Conference On Thermoelectrics (ECT2011), American Institute of Physics (AIP), 2012, p. 115-118Conference paper (Refereed)
    Abstract [en]

    Thermoelectric (TE) devices can harvest residual low-grade waste heat energy. Bismuth telluride (Bi2Te3) and its alloys are mostly used TE materials in the bulk form for making TE modules. We report a simple, fast and very high yield synthetic process for the bulk Bi2Te3 nanopowders with hexagonal plate like morphology. Spark plasma sintering (SPS) process has been optimized in order to preserve nanostructure while achieving a high compaction density of the pellets. Electron microscopy analysis was used to determine the effect of SPS parameters during compaction on the grain growth. Optimal conditions for the fabricated nanopowder was determined as 673 K, 70 MPa pressure with no holding time, which resulted in average lateral grain size in the range of 165-190 nm for a compact density of 98%. About 50% reduction of thermal conductivity was observed as compared to its bulk counterparts, revealing the feasibility of suggested route in the preservation of nanostructure and enhanced phonon scattering.

  • 86.
    Saleemi, Mohsin
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Li, Shanghua
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Johnsson, Mats
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Synthesis, processing, and thermoelectric properties of bulk nanostructured bismuth telluride (Bi(2)Te(3))2012In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 22, no 2, p. 725-730Article in journal (Refereed)
    Abstract [en]

    Bismuth telluride (Bi(2)Te(3)) is the best-known commercially used thermoelectric material in the bulk form for cooling and power generation applications at ambient temperature. However, its dimensionless figure-of-merit-ZT around 1 limits the large-scale industrial applications. Recent studies indicate that nanostructuring can enhance ZT while keeping the material form of bulk by employing an advanced synthetic process accompanied with novel consolidation techniques. Here, we report on bulk nanostructured (NS) undoped Bi(2)Te(3) prepared via a promising chemical synthetic route. Spark plasma sintering has been employed for compaction and sintering of Bi(2)Te(3) nanopowders, resulting in very high densification (>97%) while preserving the nanostructure. The average grain size of the final compacts was obtained as 90 +/- 5 nm as calculated from electron micrographs. Evaluation of transport properties showed enhanced Seebeck coefficient (-120 mu V K(-1)) and electrical conductivity compared to the literature state-of-the-art (30% enhanced power factor), especially in the low temperature range. An improved ZT for NS bulk undoped Bi(2)Te(3) is achieved with a peak value of similar to 1.1 at 340 K.

  • 87.
    Saleemi, Mohsin
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM. Stockholm University, Sweden.
    Vanapalli, S.
    Nikkam, Nader
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Classical Behavior of Alumina (Al2O3) Nanofluids in Antifrogen N with Experimental Evidence2015In: Journal of Nanomaterials, ISSN 1687-4110, E-ISSN 1687-4129, Vol. 2015, article id 256479Article in journal (Refereed)
    Abstract [en]

    A nanofluid is a suspension containing nanoparticles in conventional heat transfer fluids. This paper reports on an investigation of alumina (Al2O3) nanoparticles in Antifrogen N, also called AFN, which is a popular antifreeze coolant consisting primarily of ethylene glycol and other additives to impede corrosion. The base carrier fluid is 50% by weight of water and 50% by weight of AFN. We systematically measured the nanomaterials and heat transfer data of nanofluids for four different size particles, namely, 20, 40, 150, and 250 nm alumina particles. The pH of all the nanofluids is adjusted to have a stable dispersion. The material characterizations include SEM and DLS particle measurements. We measured thermal conductivity, viscosity, and heat transfer coefficient in developing flow of the nanofluids. We observed that these nanofluids behave as any other classical fluids in thermally developing flow and classical heat transfer correlations can be used to completely describe the characteristics of these nanofluids.

  • 88.
    Saleemi, Mohsin
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Yakhshi Tafti, Mohsen
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Stingaciu, M.
    Johnsson, M.
    Jägle, M.
    Jacquot, A.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Fabrication of nanostructured bulk cobalt antimonide (CoSb3) based skutterudites via bottom-up synthesis2013In: Thermoelectric Materials Research and Device Development for Power Conversion and Refrigeration: symposium held November 25-30, 2012, Boston, Mass., Materials Research Society, 2013, p. 121-126Conference paper (Refereed)
    Abstract [en]

    Skutterudites are known to be efficient thermoelectric (TE) materials in the temperature range from 600 K to 900 K. Dimensionless figure of merit (ZT) for filled skutterudite TE materials have been reported as ca. 1 at 800 K. Novel nano- engineering approaches and filling of the skutterudites crystal can further improve the transport properties and ultimately the ZT. Although classified among the promising TE materials, research on their large-scale production via bottom up synthetic routes is rather limited. In this work, large quantity of cobalt antimonide (CoSb3) based skutterudites nanopowder (NP) was fabricated through a room temperature coprecipitation precursor method. Dried precipitates were process by thermo-chemical treatment steps including calcination (in air) and reduction (in hydrogen). CoSb3 NPs were then mixed with silver (Ag) nanopanicles at different weight percentages (1%, 5% and 10% by wt) to form nanocomposites. Skutterudite NP was then consolidated by Spark Plasma Sintering (SPS) technique to produce highly dense compacts while maintaining the nanostructure. Temperature dependent TE characteristics of SPS'd CoSb3 and Ag containing nanocomposite samples were evaluated for transport properties, including thermal conductivity, electrical conductivity and Seebeck coefficient over the temperature range of 300-900 K. Physicochemical, structural and microstructural evaluation results are presented in detail.

  • 89.
    Sallam, Ahmed
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics. Aswan Univ, Fac Archaeol, Aswan, Egypt..
    Hemeda, Sayed
    Cairo Univ, Fac Archaeol, Conservat Dept, Cairo 12613, Egypt..
    Toprak, Muhammet
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Muhammed, Mamoun
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Hassan, Moustapha
    Karolinska Inst, Dept Lab Med, S-14186 Stockholm, Sweden..
    Uheida, Abdusalam
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    CT Scanning and MATLAB Calculations for Preservation of Coptic Mural Paintings in Historic Egyptian Monasteries2019In: Scientific Reports, E-ISSN 2045-2322, Vol. 9, article id 3903Article in journal (Refereed)
    Abstract [en]

    Investigations of Coptic mural paintings in historic churches and monasteries demand a deep understanding of the micro structure of the mural painting layers. The main objective of the present study is to study the efficiency of new avenues of computed X-ray tomography (CT Scan) and MATLAB in the analysis of Coptic mural paintings, either in the form of images or videos made to collect information about the physical characteristics of the material structure of the layers of mural paintings. These advanced techniques have been used in the investigation of samples of Coptic mural paintings dating back to the V-VIII century A.D, which have been collected from several locations in the Coptic monasteries in Upper Egypt. The application of CT-scanning is a powerful non-destructive tool for imaging and investigation which can be applied to the preservation of monuments made from many different materials. The second stage of research will be to characterize the materials through analytical techniques including XRD, XRF, EDX and FTIR to confirm the findings of CT scanning and to provide additional information concerning the materials used and their deterioration processes. This paper presents the results of the first pilot study in which CT scan and MATLAB have been utilized in combination for the non-destructive evaluation and investigation of Coptic mural paintings in Upper Egypt. The examinations have been carried out on mural painting samples from three important Coptic monasteries in Upper Egypt: the Qubbat Al Hawa Monastery in Aswan, the Saint Simeon Monastery in Aswan and the Saint Matthew the Potter Monastery in Luxor. This multi-stranded investigation has provided us with important information about the physical structure of the paintings, grains dimensions, grain texture, pore media characterization which include the micro porosity, BET and TPV, surface rendering, and calculation of the points in the surface through calculations completed using MATLAB. CT scanning assisted in the investigation and analyses of image surface details, and helped to visualize hidden micro structures that would otherwise be inaccessible due to over painting.

  • 90. Sallam, Ahmed
    et al.
    Zhao, Ying
    Hassan, Moustapha
    Toprak, Muhammet
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Uheida, Abdusalam
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Studies On The Deterioration Of Coptic Mural Paintings In The Monastery Of Martyrs And The Luxor Temple2016In: International Journal of Conservation Science, ISSN 2067-533X, E-ISSN 2067-8223, Vol. 7, no 2, p. 493-500Article in journal (Refereed)
    Abstract [en]

    In this study the surfaces and cross sections of deteriorated Coptic mural paintings were investigated using Computer Tomography (CT) scan images and video, and points (voids) on the surface were analyzed. To our knowledge, it is the first report on the application of CT scan for the investigation of deteriorated Coptic mural painting surfaces in Upper Egypt. The samples tested were collected from two sites: the Monastery of Martyrs (Deir alShuhada-Esna) and the Luxor temple. The selection of these monasteries was due to their historical importance, which is directly related to Egyptian Coptic heritage. The deteriorated surfaces of the selected mural paintings were characterized using new avenues of computed X-ray tomography (CT scan) in order to gather sufficient information about their composition and structure. The obtained results show that CT scan images provided us with detailed information about the sample porosity and structure. In the case of the Martyrs monastery, it was found that the mural paintings consist of one layer which contains clay minerals (kaolinite, montmorillonite, and illite) in the form of coarse plaster. On the other hand, the Martyrs Monastery showed higher porosity than the Roman Fresco in the Luxor Temple.

  • 91.
    Shahid, Robina
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Gorlov, Mikhail
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    El-Sayed, Ramy
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Sugunan, Abhilash
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Microwave assisted synthesis of ZnS quantum dots using ionic liquids2012In: Materials letters (General ed.), ISSN 0167-577X, E-ISSN 1873-4979, Vol. 89, p. 316-319Article in journal (Refereed)
    Abstract [en]

    In this work we report results from microwave (MW) assisted synthesis of highly crystalline ZnS quantum dots (QDs) using ionic liquid (ILs) as MW absorbing medium. Two types of ionic liquids, imidazolium and phosphonium based, were used. The QDs are less than 5 nm in size and of wurtzite ZnS type, as characterized by high-resolution transmission electron microscopy (HR-TEM) and selected area electron diffraction (SAED) pattern. The optical properties were investigated by UV-vis absorption and show a blue shift in absorption as compared to bulk wurtzite ZnS due to quantum confinement effects. The photoluminescence (PL) spectra of the QDs show different trap state emissions.

  • 92. Shahid, Robina
    et al.
    Muhammad, Nawshad
    Gonfa, Girma
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Synthesis, COSMO-RS analysis and optical properties of surface modified ZnS quantum dots using ionic liquids2015In: Journal of Physics and Chemistry of Solids, ISSN 0022-3697, E-ISSN 1879-2553, Vol. 85, p. 34-38Article in journal (Refereed)
    Abstract [en]

    Zinc sulfide (ZnS) quantum dots (QDs) were synthesized using the microwave assisted ionic liquid (MAIL) route. Three ionic liquids (ILs), namely, 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]), trihexyl(tetradecyl) phosphonium bis(trifluoromethanesulfonyl) amide ([P-6,P-6,P-6,P-14][TSFA]) and trihexyl (tetradecyl) phosphonium chloride ([P-6,P-6,P-6,P-14][Cl]) were used in this study. The size and structure of the QDs were characterized by high-resolution transmission electron microscopy (HR-TEM) and selected area electron diffraction (SAED) pattern, respectively. The synthesized QDs were of wurtzite crystalline structure with size less than 5 nm. The QDs were more uniformly distributed while using the phosponium based ILs as a reaction medium during synthesis. The optical properties were investigated by UV-vis absorption and photoluminescence (PL) emission spectroscopy. The optical properties of QDs showed the quantum confinement effect in their absorption and the effect of cation and anion structural moiety was observed on their bandedge emission. The QDs emission intensity was measured higher for [P-6,P-6,P-6,P-14][Cl] due to their better dispersion as well as high charge density of Cl anion. The capability of the ILs in stabilizing the QDs was interpreted by density functional theory (DFT) computations. The obtained results are in good agreement with the theoretical prediction.

  • 93.
    Shahid, Robina
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Microwave-assisted low temperature synthesis of wurtzite ZnS quantum dots2012In: Journal of Solid State Chemistry, ISSN 0022-4596, E-ISSN 1095-726X, Vol. 187, p. 130-133Article in journal (Refereed)
    Abstract [en]

    In this work we report, for the first time, on microwave assisted synthesis of wurtzite ZnS quantum dots (QDs) in controlled reaction at temperature as low as 150 degrees C. The synthesis can be done in different microwave absorbing solvents with multisource or single source precursors. The QDs are less than 3 nm in size as characterized by transmission electron microscopy (TEM) using selected area electron diffraction (SAED) patterns to confirm the wurtzite phase of ZnS QDs. The optical properties were investigated by UV-Vis absorption which shows blue shift in absorption compared to bulk wurtzite ZnS due to quantum confinement effects. The photoluminescence (PL) spectra of QDs reveal point defects related emission of ZnS QDs.

  • 94.
    Shahid, Robina
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Material Physics.
    Soliman, Hesham M. A.
    KTH, School of Information and Communication Technology (ICT), Material Physics.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Low temperature synthesis of cubic phase zinc sulfide quantum dots2012In: Central European Journal of Chemistry, ISSN 1895-1066, E-ISSN 1644-3624, Vol. 10, no 1, p. 54-58Article in journal (Refereed)
    Abstract [en]

    In this study, we report on a new method for the synthesis of ZnS quantum dots (QDs). The synthesis was carried out at low temperature by a chemical reaction between zinc ions and freshly reduced sulfide ions in ethanol as reaction medium. Zinc chloride and elemental sulfur were used as zinc and sulfur sources, respectively and hydrazine hydrate was used as a strong reducing agent to convert elemental sulfur (S(8)) into highly reactive sulfide ions (S(2-)) which react spontaneously with zinc ions. This facile, less toxic, inexpensive route has a high yield for the synthesis of high quality metal sulfide QDs. Transmission electron microscopy (TEM) image analysis and selected area electron diffraction (SAED) reveal that ZnS QDs are less than 3 nm in diameter and are of cubic crystalline phase. The UV-Vis absorption spectrum shows an absorption peak at 253 nm corresponding to a band gap of 4.9 eV, which is high when compared to the bulk value of 3.68 eV revealing strong quantum confinement. PL emission transitions are observed at 314 nm and 439 nm and related to point defects in ZnS QDs.

  • 95. Shi, Jingwen
    et al.
    Karlsson, Hanna L.
    Johansson, Katarina
    Gogvadze, Vladimir
    Xiao, Lisong
    Li, Jiangtian
    Burks, Terrance
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Garcia-Bennett, Alfonso
    Uheida, Abdusalam
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Mathur, Sanjay
    Morgenstern, Ralf
    Kagan, Valerian E.
    Fadeel, Bengt
    Microsomal Glutathione Transferase 1 Protects Against Toxicity Induced by Silica Nanoparticles but Not by Zinc Oxide Nanoparticles2012In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 6, no 3, p. 1925-1938Article in journal (Refereed)
    Abstract [en]

    Microsomal glutathione transferase 1 (MGST1) is an antioxidant enzyme located predominantly in the mitochondrial er membrane and endoplasmk reticulum and has been shown to protect cells from lipid peroxidation induced by a variety of cytostatic drugs and pro-oxidant stimuli. We hypothesized that MGST1 may also protect against nanomaterial-induced cytotoxicity through a specific effect on lipid peroxidation. We evaluated the induction of cytotoxicity and oxidative stress by TiO2, CeO2, SiO2, and ZnO in the human MCF-7 cell line with or without overexpression of MGST1. SiO2 and ZnO nanoparticles caused dose- and time-dependent toxicity, whereas no obvious cytotoxic effects were induced by nanoparticles of TiO2 and CeO2. We also noted pronounced cytotoxicity for three out of four additional SiO2 nanoparticles tested. Overexpression of MGST1 reversed the cytotoxicity of the main SiO2 nanoparticles tested and for one of the supplementary SiO2 nanoparticles but did not protect cells against ZnO-induced cytotoxic effects. The data point toward a role of lipid peroxidation In SiO2 nanoparticle-induced cell death. For ZnO nanoparticles, rapid dissolution was observed, and the subsequent interaction of Zn2+ with cellular targets is likely to contribute to the cytotoxic effects. A direct inhibition of MGST1 by Zn2+ could provide a possible explanation for the lack of protection against ZnO nanoparticles in this model. Our data also showed that SiO2 nanoparticle-induced cytotoxicity is mitigated in the presence of serum, potentially through masking of reactive surface groups by serum proteins, whereas ZnO nanoparticles were cytotoxic both In the presence and in the absence of serum.

  • 96.
    Singh, Sathya P.
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Nikkam, Nader
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Ghanbarpour, Morteza
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Toprak, Muhammet
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Khodabandeh, Rahmatollah
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Design and Evaluation of Carbon Nanotube Based Nanofluids for Heat Transfer Applications2013In: MRS Spring 2013 Proceedings: Symposium on Nanoscale Heat Transport—From Fundamentals to Devices, Materials Research Society, 2013Conference paper (Refereed)
    Abstract [en]

    The present work investigates the fabrication, thermal conductivity (TC) and rheological properties of water based carbon nanotubes (CNTs) nanofluids (NFs) prepared using a two-step method. As-received (AR) CNTs heated and the effect of heat treatment was studied using X-ray diffraction and thermogravimetric analysis. The AR-CNTs and heat-treated CNTs (HT-CNTs) were dispersed with varying concentration of surface modifiers Gum Arabic (GA) and TritonX-100 (TX) respectively. It was found that heat treatment of CNTs effectively improved the TC and influenced rheological properties of NFs. Scanning electron microscopy analysis revealed TX modified NFs showed better dispersion ability compared to GA. Surface modification of the CNTs was confirmed by Fourier Transformation Infrared (FTIR) analysis. Zeta potential measurement showed the stability region for GA modified NFs in the pH range of 5-11, whereas pH was between 9.5-10 for TX NFs. The concentration of surface modifier plays an extensive role on both TC and rheological behavior of NFs. A maximum TC enhancement of 10% with increases in viscosity around 2% for TX based HT-CNTs NFs was measured. Finally comparison of experimental TC results with the predicted values obtained from a model demonstrated inadequacy of the predictive model for CNT NFs system.

  • 97.
    Sugunan, Abhilash
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Guduru, Veerendra K.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Uheida, Abdusalam
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Radially Oriented ZnO Nanowires on Flexible Poly-L-Lactide Nanofibers for Continuous-Flow Photocatalytic Water Purification2010In: Journal of The American Ceramic Society, ISSN 0002-7820, E-ISSN 1551-2916, Vol. 93, no 11, p. 3740-3744Article in journal (Refereed)
    Abstract [en]

    Several oxide ceramics, notably ZnO and TiO2 are known to catalyze decomposition of organic molecules in water under ultraviolet (UV) irradiation. Here we describe fabrication of highly flexible ZnO-based hierarchical nanostructure obtained by growing radially oriented ZnO nanowires on poly-L-lactide nanofibers. Utilizing the flexibility and high surface area of polymeric nanofibers as novel substrate for growth of the photochemically active ZnO nanowires we show a proof-of-principle demonstration of a continuous flow water treatment setup. We have monitored photocatalytic decomposition of known organic pollutants, such as methylene blue, monocrotophos, and diphenylamine under illumination with UV light using this highly flexible hierarchical nanostructure.

  • 98.
    Sugunan, Abhilash
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Jafri, S. Hassan M.
    Qin, Jian
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Blom, Tobias
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Leifer, Klaus
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Low-temperature synthesis of photoconducting CdTe nanotetrapods2010In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 20, no 6, p. 1208-1214Article in journal (Refereed)
  • 99.
    Sugunan, Abhilash
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Zhao, Yichen
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Mitra, Somak
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Optics.
    Dong, Lin
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Optics.
    Li, Shanghua
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Optics.
    Marcinkevicius, Saulius
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Optics.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Synthesis of tetrahedral quasi-type-II CdSe-CdS core-shell quantum dots2011In: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 22, no 42, p. 425202-Article in journal (Refereed)
    Abstract [en]

    Synthesis of colloidal nanocrystals of II-VI semiconductor materials has been refined in recent decades and their size dependent optoelectronic properties have been well established. Here we report a facile synthesis of CdSe-CdS core-shell heterostructures using a two-step hot injection process. Red-shifts in absorption and photoluminescence spectra show that the obtained quantum dots have quasi-type-II alignment of energy levels. The obtained nanocrystals have a heterostructure with a large and highly faceted tetrahedral CdS shell grown epitaxially over a spherical CdSe core. The obtained morphology as well as high resolution electron microscopy confirms that the tetrahedral shell have a zinc blende crystal structure. A phenomenological mechanism for the growth and morphology of the nanocrystals is discussed.

  • 100.
    Tafti, Mohsen Yakshi
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Saleemi, Mohsin
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Toprak, Muhammet S
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Johnsson, Mats
    Stockholm University.
    Jacquot, Alexandre
    Jägle, Martin
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Fabrication and characterization of nanostructured thermoelectric FexCo1-xSb32015In: Open Chemistry, E-ISSN 2391-5420, Vol. 13, no 1, p. 629-635Article in journal (Refereed)
    Abstract [en]

    A novel synthesis route for the fabrication of p-type nanostructured skutterudite, FexCo1-xSb3 in large quantity is reported. This scalable synthesis route provides nano-engineered material with less impact on the environment compared to conventional synthesis procedures. Several Fe substituted compositions have been synthesized to confirm the feasibility of the process. The process consists of a nano-sized precursor fabrication of iron and cobalt oxalate, and antimony oxides by chemical co-precipitation. Further thermochemical processes result in the formation of iron substituted skutterudites. The nanopowders are compacted by Spark Plasma Sintering (SPS) technique in order to maintain nanostructure. Detailed physicochemical as well as thermoelectric transport properties are evaluated. Results reveal strongly reduced thermal conductivity values compared to conventionally prepared counterparts, due to nanostructuring. P-type characteristic was observed from the Seebeck measurements while electrical conductivity is high and shows metallic behavior. The highest TE figure of merit of 0.25 at 800 K has been achieved, which is strongly enhanced with respect to the mother compound CoSb3. This suggests the promise of the utilized method of fabrication and processing for TE applications with improved performance.

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