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Sallam, A., Hemeda, S., Toprak, M., Muhammed, M., Hassan, M. & Uheida, A. (2019). CT Scanning and MATLAB Calculations for Preservation of Coptic Mural Paintings in Historic Egyptian Monasteries. Scientific Reports, 9, Article ID 3903.
Open this publication in new window or tab >>CT Scanning and MATLAB Calculations for Preservation of Coptic Mural Paintings in Historic Egyptian Monasteries
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2019 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, article id 3903Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
NATURE PUBLISHING GROUP, 2019
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-247812 (URN)10.1038/s41598-019-40297-z (DOI)000460508600133 ()30846738 (PubMedID)2-s2.0-85062614465 (Scopus ID)
Note

QC 20190401

Available from: 2019-04-01 Created: 2019-04-01 Last updated: 2019-04-01Bibliographically approved
Wärnheim, A., Toprak, M., Ahniyaz, A., Swerin, A. & Abitbol, T. (2019). Nanocellulose-based hybrid materials for optical applications. Paper presented at National Meeting of the American-Chemical-Society (ACS), MAR 31-APR 04, 2019, Orlando, FL. Abstracts of Papers of the American Chemical Society, 257
Open this publication in new window or tab >>Nanocellulose-based hybrid materials for optical applications
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2019 (English)In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 257Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
National Category
Biomedical Laboratory Science/Technology
Identifiers
urn:nbn:se:kth:diva-257626 (URN)000478860502461 ()
Conference
National Meeting of the American-Chemical-Society (ACS), MAR 31-APR 04, 2019, Orlando, FL
Note

QC 20190918

Available from: 2019-09-18 Created: 2019-09-18 Last updated: 2019-10-15Bibliographically approved
Larsson, J. C., Vogt, C., Vågberg, W., Toprak, M., Dzieran, J., Arsenian-Henriksson, M. & Hertz, H. (2018). High-spatial-resolution x-ray fluorescence tomography with spectrally matched nanoparticles. Physics in Medicine and Biology, 63, 164001
Open this publication in new window or tab >>High-spatial-resolution x-ray fluorescence tomography with spectrally matched nanoparticles
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2018 (English)In: Physics in Medicine and Biology, ISSN 0031-9155, E-ISSN 1361-6560, Vol. 63, p. 164001-Article in journal (Refereed) Published
Abstract [en]

Present macroscopic biomedical imaging methods provide either morphology with high spatial resolution (e.g. CT) or functional/molecular information with lower resolution (e.g. PET). X-ray fluorescence (XRF) from targeted nanoparticles allows molecular or functional imaging but sensitivity has so far been insufficient resulting in low spatial resolution, despite long exposure times and high dose. In the present paper, we show that laboratory XRF tomography with metal-core nanoparticles (NPs) provides a path to functional/molecular biomedical imaging with ~100 µm resolution in living rodents. The high sensitivity and resolution rely on the combination of a high-brightness liquid-metal-jet x-ray source, pencil-beam optics, photon-counting energy-dispersive detection, and spectrally matched NPs. The method is demonstrated on mice for 3D tumor imaging via passive targeting of in-house-fabricated molybdenum NPs. Exposure times, nanoparticle dose, and radiation dose agree well with in vivo imaging.

Place, publisher, year, edition, pages
Institute of Physics (IOP), 2018
Keywords
x-ray, x-ray fluorescence, tomography, nanoparticles
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-233331 (URN)10.1088/1361-6560/aad51e (DOI)000441712300001 ()2-s2.0-85052501337 (Scopus ID)
Funder
Swedish Research CouncilWallenberg Foundations
Note

QC 20180828

Available from: 2018-08-15 Created: 2018-08-15 Last updated: 2018-10-16Bibliographically approved
Kertmen, A., Torruella, P., Coy, E., Yate, L., Nowaczyk, G., Gapinski, J., . . . Andruszkiewicz, R. (2017). Acetate-Induced Disassembly of Spherical Iron Oxide Nanoparticle Clusters into Monodispersed Core-Shell Structures upon Nanoemulsion Fusion. Langmuir, 33(39), 10351-10365
Open this publication in new window or tab >>Acetate-Induced Disassembly of Spherical Iron Oxide Nanoparticle Clusters into Monodispersed Core-Shell Structures upon Nanoemulsion Fusion
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2017 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 33, no 39, p. 10351-10365Article in journal (Refereed) Published
Abstract [en]

It has been long known that the physical encapsulation of oleic acid-capped iron oxide nanoparticles (OA-IONPs) with the cetyltrimethylammonium (CTA(+)) surfactant induces the formation of spherical iron oxide nanoparticle clusters (IONPCs). However, the behavior and functional properties of IONPCs in chemical reactions have been largely neglected and are still not well-understood. Herein, we report an unconventional ligand-exchange function of IONPCs activated when dispersed in an ethyl acetate/acetate buffer system. The ligand exchange can successfully transform hydrophobic OA-IONP building blocks of IONPCs into highly hydrophilic, acetate-capped iron oxide nanoparticles (Ac-IONPs). More importantly, we demonstrate that the addition of silica precursors (tetraethyl orthosilicate and 3-aminopropyltriethoxysilane) to the acetate/oleate ligand-exchange reaction of the IONPs induces the disassembly of the IONPCs into monodispersed iron oxide-acetate-silica core-shell-shell (IONPs@acetate@SiO2) nanoparticles. Our observations evidence that the formation of IONPs@acetate@SiO2 nanoparticles is initiated by a unique micellar fusion mechanism between the Pickering-type emulsions of IONPCs and nanoemulsions of silica precursors formed under ethyl acetate buffered conditions. A dynamic rearrangement of the CTA(+)-oleate bilayer on the IONPC surfaces is proposed to be responsible for the templating process of the silica shells around the individual IONPs. In comparison to previously reported methods in the literature, our work provides a much more detailed experimental evidence of the silica-coating mechanism in a nanoemulsion system. Overall, ethyl acetate is proven to be a very efficient agent for an effortless preparation of monodispersed IONPs@acetate@SiO2 and hydrophilic Ac-IONPs from IONPCs.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2017
National Category
Materials Chemistry
Identifiers
urn:nbn:se:kth:diva-217041 (URN)10.1021/acs.langmuir.7b02743 (DOI)000412718700025 ()28895402 (PubMedID)2-s2.0-85030677707 (Scopus ID)
Note

QC 20171101

Available from: 2017-11-01 Created: 2017-11-01 Last updated: 2018-02-26Bibliographically approved
Nikkam, N., Toprak, M., Dutta, J., Al-Abri, M., Myint, M. T., Souayeh, M. & Mohseni, S. M. (2017). Fabrication and thermo-physical properties characterization of ethylene glycol-MoS2 heat exchange fluids. International Communications in Heat and Mass Transfer, 89, 185-189
Open this publication in new window or tab >>Fabrication and thermo-physical properties characterization of ethylene glycol-MoS2 heat exchange fluids
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2017 (English)In: International Communications in Heat and Mass Transfer, ISSN 0735-1933, E-ISSN 1879-0178, Vol. 89, p. 185-189Article in journal (Refereed) Published
Abstract [en]

This study reports on the fabrication and thermo-physical properties evaluation of ethylene glycol (EG) based heat exchange fluids containing molybdenum disulfide nanoparticles (MoS2 NPs) and micrometer sized particles (MPs). For this purpose, MoS2 NPs and MPs (with average size of 90 nm and 1.2 mu m; respectively) were dispersed and stabilized in EG with particle loading of 0.25, 0.5, 1 wt%. To study the real effect of MoS2 NP/MP the use of surfactants was avoided and ultrasonic agitation was used for dispersion and preparation of stable MoS2 NFs/MFs. The objectives were investigation of impact of MoS2 particle size (including NP/MP) and particle loading on thermo-physical properties of EG based MoS2 NFs/MFs including thermal conductivity (TC) and viscosity of NFs/MFs at 20 degrees C. All suspensions (NFs/MFs) exhibited a higher TC than the EG as base liquid and NFs showed higher TC enhancement values than the MFs. A TC enhancement of 16.4% was observed for NFs containing 1 wt % MoS2 NPs while the maximum increase in viscosity of 9.7% was obtained for the same NF at 20 degrees C. It indicates this NF system may have some potential to be utilized in heat transfer applications.

Place, publisher, year, edition, pages
PERGAMON-ELSEVIER SCIENCE LTD, 2017
Keywords
MoS2 nanoparticles, MoS2 microparticles, Nanofluids, Microfluids thermal conductivity, Viscosity, Thermo-physical property
National Category
Applied Mechanics
Identifiers
urn:nbn:se:kth:diva-221874 (URN)10.1016/j.icheatmasstransfer.2017.10.011 (DOI)000419412500021 ()
Note

QC 20180131

Available from: 2018-01-31 Created: 2018-01-31 Last updated: 2018-01-31Bibliographically approved
Toprak, M., Li, S. & Muhammed, M. (2017). Fabrication routes for nanostructured TE material architectures. In: Materials, Preparation, and Characterization in Thermoelectrics: (pp. 17-1-17-18). CRC Press
Open this publication in new window or tab >>Fabrication routes for nanostructured TE material architectures
2017 (English)In: Materials, Preparation, and Characterization in Thermoelectrics, CRC Press , 2017, p. 17-1-17-18Chapter in book (Other academic)
Abstract [en]

Nanomaterials have been an emerging œeld of research due to the novel properties exhibited when the size of building blocks is reduced below 100 nm. Several size-dependent phenomena make nanomaterials attractive in terms of potential applicability compared to their larger-sized counterparts, justifying the importance and attention of this research.1-3 For thermoelectric research, nanomaterials are of great interest due to the possibility of decoupling electrical and thermal transport properties which may help attain higher ZT values for the currently available materials.4,5 še commonly accepted nomenclature of nanomaterials is based on the number of degrees of freedom of charge carriers for the description of their dimensionalities. šus, a thin œlm or superlattice is conœned in one dimension, but is a 2D nanomaterial. Similarly, a nanowire is conœned in two dimensions, hence is a 1D nanomaterial, and œnally a nanoparticle is conœned in three dimensions and is therefore a 0D nanomaterial. In the case of larger nanocrystals (not quantum conœned), the size and shape of the nanocrystals also affect their properties due to differences in surface-to-volume ratio. Bulk nanostructured (NS) TE materials are fabricated using a bulk process rather than a nanofabrication process, which has the important advantage of being produced in large quantities and in a form that is compatible with commercially available devices.6 šey are different from the advanced low-dimensional TE materials as they are consolidated under high T and P, resulting in larger-sized (40-200 nm) grains. še advanced low-dimensional TE materials are usually in quantum size and have well-deœned shapes such as rod-like or tube-like structures. še nanoeffects of bulk NS TE materials will not be as strong as in the case of advanced low-dimensional TE materials, but since the material is closer to bulk material, it can be easily handled the same way as bulk TE materials using conventional TE module/device technology for further steps toward direct applications. So far, of all the NS materials, only bulk NS materials have been produced in enough quantity to be used in this manner. 

Place, publisher, year, edition, pages
CRC Press, 2017
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-236811 (URN)10.1201/b11891 (DOI)2-s2.0-85051958883 (Scopus ID)9781439874714 (ISBN)9781439874707 (ISBN)
Note

QC 20190107

Available from: 2019-01-07 Created: 2019-01-07 Last updated: 2019-01-07Bibliographically approved
Mohamed, A., Yousef, S., Ali Abdelnaby, M., Osman, T. A., Hamawandi, B., Toprak, M. S., . . . Uheida, A. (2017). Photocatalytic degradation of organic dyes and enhanced mechanical properties of PAN/CNTs composite nanofibers. Separation and Purification Technology, 182, 219-223
Open this publication in new window or tab >>Photocatalytic degradation of organic dyes and enhanced mechanical properties of PAN/CNTs composite nanofibers
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2017 (English)In: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 182, p. 219-223Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Elsevier, 2017
Keywords
Composite nanofibers, Mechanical properties, Photodegradation, Carbon, Carbon nanotubes, Elastic moduli, Irradiation, Tensile strength, Yarn, Electrospinning process, Organic dye, Photo catalytic degradation, Polyacrylonitrile (PAN), Structure and morphology, UV irradiation, Volume concentration, Nanofibers
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-207443 (URN)10.1016/j.seppur.2017.03.051 (DOI)000401393700025 ()2-s2.0-85016937303 (Scopus ID)
Note

QC 20170523

Available from: 2017-05-23 Created: 2017-05-23 Last updated: 2017-06-14Bibliographically approved
Mohamed, A., Osman, T. A., Toprak, M. S., Muhammed, M. & Uheida, A. (2017). Surface functionalized composite nanofibers for efficient removal of arsenic from aqueous solutions. Chemosphere, 180, 108-116
Open this publication in new window or tab >>Surface functionalized composite nanofibers for efficient removal of arsenic from aqueous solutions
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2017 (English)In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 180, p. 108-116Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Elsevier Ltd, 2017
Keywords
Arsenic adsorption, Composite nanofibers, Electrospinning, Isotherm, Kinetics
National Category
Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-207283 (URN)10.1016/j.chemosphere.2017.04.011 (DOI)000401880500013 ()2-s2.0-85017101033 (Scopus ID)
Note

QC 20170619

Available from: 2017-06-19 Created: 2017-06-19 Last updated: 2017-06-19Bibliographically approved
Saleemi, M., Tafti, M. Y., Jacquot, A., Jaegle, M., Johnson, M. & Toprak, M. S. (2016). Chemical Synthesis of Iron Antimonide (FeSb2) and Its Thermoelectric Properties. Inorganic Chemistry, 55(4), 1831-1836
Open this publication in new window or tab >>Chemical Synthesis of Iron Antimonide (FeSb2) and Its Thermoelectric Properties
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2016 (English)In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 55, no 4, p. 1831-1836Article in journal (Refereed) Published
Abstract [en]

Low temperature thermoelectric (TE) materials are in demand for more efficient cooling and power generation applications. Iron antimonide (FeSb2) draws great attention over the past few years because of its enhanced power factor values. Polycrystalline bulk FeSb2 nanopowder was prepared via a low-temperature molten salts approach followed by subsequent thermal treatment in synthetic air and hydrogen gas for calcination and reduction reactions, respectively. Structural analysis confirms the desired final phase with submicrometer grain size and high compaction density after consolidation using spark plasma sintering (SPS). TE transport properties revealed that the material is n-type below 150 K and p-type above this temperature; this suggests antimony vacancies in FeSb2. The electrical conductivity increased significantly, and the highest conductivity achieved was 6000 S/cm at 100 K. The maximum figure-of-merit, ZT, of 0.04 is achieved at 500 K, which is about 6 times higher than the earlier reported state-of-the art ZT value for the same material.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2016
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-184039 (URN)10.1021/acs.inorgchem.5b02658 (DOI)000370395000055 ()26836130 (PubMedID)2-s2.0-84958818272 (Scopus ID)
Note

QC 20160323

Available from: 2016-03-23 Created: 2016-03-22 Last updated: 2017-11-30Bibliographically approved
Mohamed, A., El-Sayed, R., Osman, T. A., Toprak, M., Muhammed, M. A. & Uheida, A. (2016). Composite nanofibers for highly efficient photocatalytic degradation of organic dyes from contaminated water. Environmental Research, 145, 18-25
Open this publication in new window or tab >>Composite nanofibers for highly efficient photocatalytic degradation of organic dyes from contaminated water
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2016 (English)In: Environmental Research, ISSN 0013-9351, E-ISSN 1096-0953, Vol. 145, p. 18-25Article in journal (Refereed) Published
Abstract [en]

In this study highly efficient photocatalyst based on composite nanofibers containing polyacrylonitrile (PAN), carbon nanotubes (CNT), and surface functionalized TiO2 nanoparticles was developed. The composite nanofibers were fabricated using electrospinning technique followed by chemical crosslinking. The surface modification and morphology changes of the fabricated composite nanofibers were examined through SEM, TEM, and FTIR analysis. The photocatalytic performance of the composite nanofibers for the degradation of model molecules, methylene blue and indigo carmine, under UV irradiation in aqueous solutions was investigated. The results demonstrated that high photodegradation efficiency was obtained in a short time and at low power intensity compared to other reported studies. The effective factors on the degradation of the dyes, such as the amount of catalyst, solution pH and irradiation time were investigated. The experimental kinetic data were fitted using pseudo-first order model. The effect of the composite nanofibers as individual components on the degradation efficiency of MB and IC was evaluated in order to understand the overall photodegradation mechanism. The results obtained showed that all the components possess significant effect on the photodegradation activity of the composite nanofibers. The stability studies demonstrated that the photodegradation efficiency can remain constant at the level of 99% after five consecutive cycles.

Place, publisher, year, edition, pages
Elsevier, 2016
Keywords
Carbon nanotubes (CNTs), Composite nanofibers, Electrospinning, Organic contaminants, Photocatalytic
National Category
Other Chemistry Topics
Identifiers
urn:nbn:se:kth:diva-181428 (URN)10.1016/j.envres.2015.09.024 (DOI)000368218700003 ()2-s2.0-84947786246 (Scopus ID)
Note

QC 20160204. QC 20160220

Available from: 2016-02-04 Created: 2016-02-02 Last updated: 2017-11-30Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0001-5678-5298

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