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  • 122901. Zalesny, Robert
    et al.
    Gora, Robert W.
    Kozlowska, Justyna
    Luis, Josep M.
    Ågren, Hans
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Bartkowiak, Wojciech
    Resonant and Nonresonant Hyperpolarizabilities of Spatially Confined Molecules: A Case Study of Cyanoacetylene2013Ingår i: Journal of Chemical Theory and Computation, ISSN 1549-9618, E-ISSN 1549-9626, Vol. 9, nr 8, s. 3463-3472Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this theoretical study we report on resonant and nonresonant electric-dipole (hyper)polarizabilities of cyanoacetylene molecule confined by repulsive potentials of cylindrical symmetry mimicking a topology of nanotubelike carbon cages. The set of investigated electronic properties encompasses dipole moment, polarizability, first and second hyperpolarizability as well as the two-photon transition matrix elements. The effect of external potential on vibrational contributions to electric-dipole properties is also included in our treatment. The computations are performed at several levels of theoretical approximation including state-of-the-art coupled-cluster (CCSD(T)) and multireference configuration interaction methods (MRCISD(Q)). The results of calculations presented herein indicate that the decrease in dipole moment observed experimentally for the HCCCN molecule solvated in helium nanodroplets may be partially attributed to the confinement effects. The external confining potential causes a substantial drop of the isotropic average electronic polarizability and second hyperpolarizability. In contrast, the vector component of the electronic first hyperpolarizability substantially increases. Nuclear relaxation contributions to all studied electric-dipole properties are found to diminish upon confinement. Our calculations also indicate that the most intense (1)Sigma(+) <- (X) over tilde one-photon transition is slightly blue-shifted whereas the corresponding oscillator strength is virtually unaffected upon confinement. Interestingly, the absolute magnitude of the diagonal component of the second-order transition moment for the bright state (S-zz(0 -> 1)Sigma(+)) increases with the strength of external potential. The effect of structural relaxation on the electric-dipole properties, arising from the presence of the external potential, is also investigated in the present work.

  • 122902. Zalesny, Robert
    et al.
    Murugan, N. Arul
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Tian, Guangjun
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Medved, Miroslav
    Ågren, Hans
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    First-Principles Simulations of One- and Two-Photon Absorption Band Shapes of the Bis(BF2) Core Complex2016Ingår i: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 120, nr 9, s. 2323-2332Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Motivated by the outstanding properties of bis(BF2) core complexes as fluorophore probes, we present a systematic computational study of their vibrationally resolved one- and two-photon absorption spectra in vacuum and in solution. Electronic and vibrational structure calculations were performed using the coupled cluster CC2 method and the Kohn-Sham formulation of density functional theory (DFT). A nonempirical estimation of the inhomogeneous broadening, accomplished using the polarizable embedding (PE) approaches combined with time-dependent DFT and CC2 methods, is used as a key ingredient of the computational protocol employed for simulations of the spectral features in solution. The inhomogeneous broadening is also determined based on the Marcus theory employing linear response and state-specific polarizable continuum model (PCM) methods. It is found that the polarizable embedding CC2 and the state-specific PCM are the most successful approaches for description of environmental broadening. For the 1(1)A(g) -> 1(1)B(u) transition, the non-Condon effects can be safely neglected and a fair agreement between the simulated and experimental band shapes is found. In contrast, the shape of the vibrationally resolved band corresponding to the two-photon allowed 1(1)A(g) -> 2(1)A(g) transition is largely dominated by non-Condon effects. A generalized few-level model was also employed to analyze the mechanism of the electronic two-photon 1(1)A(g) -> 2(1)A(g) excitation. It was found that the most important optical channel involves the 1(1)B(u) excited state. Ramifications of the findings for general band shape modeling are briefly discussed.

  • 122903.
    Zalesny, Robert
    et al.
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Murugan, Natarajan Arul
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Gel'mukhanov, Faris
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Rinkevicius, Zilvinas
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi. KTH, Centra, SeRC - Swedish e-Science Research Centre.
    Osmialowski, Borys
    Bartkowiak, Wojciech
    Ågren, Hans
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Toward Fully Nonempirical Simulations of Optical Band Shapes of Molecules in Solution: A Case Study of Heterocyclic Ketoimine Difluoroborates2015Ingår i: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 119, nr 21, s. 5145-5152Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study demonstrates that a hybrid density functional theory/molecular mechanics approach can be successfully combined with time-dependent wavepacket approach to predict the shape of optical bands for molecules in solutions, including vibrational fine structure. A key step in this treatment is the estimation of the inhomogeneous broadening based on the hybrid approach, where the polarization between solute and atomically decomposed solvent is taken into account in a self-consistent manner. The potential of this approach is shown by predicting optical absorption bands for three heterocyclic ketoimine difluoroborates in solution.

  • 122904.
    Zalet, Ayman
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Data- och elektroteknik.
    Vklass datalagring: En studie om datalagring på ett kostands- och prestandaeffektivt sätt2016Självständigt arbete på grundnivå (högskoleexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Studien som utförs i detta examensarbete behandlar ämnet datalagring för applikationen Vklass. Problemet som studeras i detta arbete består i att det varje månad inkommer ett stort antal filer till applikationen som lagras på en server lokalt i Stockholm där regelbun-den säkerhetskopiering görs till en annan server. Den implementerade datalagringslösning-en innebär att servern som lagrar data växer ständigt och utan särskild struktur då filerna lagras i en och samma mapp, vilket i sin tur innebär en mer komplex och mindre överskåd-lig lagring av filerna i lagringsmedierna samtidigt som prestandabegränsningar uppstår vid återläsning av säkerhetskopian. Kunden efterfrågar en lösning som innebär en mer effektiv hantering för alla de filer som lagras i applikationen på ett kostnads- och prestandaeffektivt vis. Lösningen bör även möjliggöra lagring av data med en mer överskådlig och lätthanter-lig struktur.

    De lösningsmetoder som undersökts i arbetet avser datalagring lokalt samt datalagring i molntjänster från de mest framstående aktörerna. Undersökningen och analysen av de valda lösningsmetoderna visade att datalagring i molntjänster uppfyller kraven som den nya data-lagringslösningen ämnar uppnå till skillnad från datalagring lokalt som visade brister och som därmed inte uppfyllde dessa krav. Slutsatsen i arbetet identifierade Microsoft Azure Storage som den mest lämpliga molnleverantören för datalagring då data lagras på ett pre-standa- och struktureffektivt sätt. Lösningen är även kostnadseffektiv då det dyraste lag-ringsalternativet som Microsoft erbjuder sänker lagringskostnaderna för Vklass med 84 % under de kommande fem åren i jämförelse med aktuell lagringsmetod.

  • 122905. Zalewski, M.
    et al.
    Olbratowski, P.
    Rafalski, M.
    Satula, Wojtek
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Werner, T. R.
    Wyss, Ramon A.
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Global nuclear structure effects of the tensor interaction2009Ingår i: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 80, nr 6, s. 064307-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A direct fit of the isoscalar spin-orbit (SO) and both isoscalar and isovector tensor coupling constants to the f(5/2)-f(7/2) SO splittings in Ca-40, Ni-56, and Ca-48 nuclei requires a drastic reduction of the isoscalar SO strength and strong attractive tensor coupling constants. The aim of this work is to address further consequences of these strong attractive tensor and weak SO fields on binding energies, nuclear deformability, and high-spin states. In particular, the contribution to the nuclear binding energy from the tensor field shows a generic magic structure with tensorial magic numbers N(Z)=14,32,56, or 90, corresponding to the maximum spin asymmetries in 1d(5/2), 1f(7/2)circle plus 2p(3/2), 1g(9/2)circle plus 2d(5/2), and 1h(11/2)circle plus 2f(7/2) single-particle configurations, respectively, and that these numbers are smeared out by pairing correlations and deformation effects. The consequences of strong attractive tensor fields and weak SO interaction for nuclear stability at the drip lines are also examined, particularly those close to the tensorial doubly magic nuclei. The possibility of an entirely new tensor-force-driven deformation effect is discussed.

  • 122906. Zalewski, M.
    et al.
    Satula, Wojtek
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Dobaczewski, J.
    Olbratowski, P.
    Rafalski, M.
    Werner, T. R.
    Wyss, Ramon
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnfysik.
    Shell structure fingerprints of tensor interaction2009Ingår i: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 42, nr 3, s. 577-581Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We address the consequences of strong tensor terms in the local energy density functional, resulting from fits to the f(5/2)-f(7/2) splittings in Ca-40, Ca-48, and Ni-56. In this study, we focus on the tensor contribution to the nuclear binding energy. In particular, we show that it exhibits an interesting topological feature closely resembling that of the shell correction. We demonstrate that in the extreme single-particle scenario at spherical shape, the tensor contribution shows tensorial magic numbers equal to N(Z) = 14, 32, 56, and 90, and that this structure is smeared out due to configuration mixing caused by pairing correlations and migration of proton/neutron sub-shells with neutron/proton shell filling. Based on a specific Skyrme-type functional SLy4(T), we show that the proton tensorial magic numbers shift with increasing neutron excess to Z = 14, 28, and 50.

  • 122907.
    Zaleśny, Robert
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Anharmonicity contributions to the vibrational first and second hyperpolarizability of para-disubstituted benzenes2014Ingår i: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 595, s. 109-112Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this Letter, we report on the anharmonicity contributions to the static vibrational first and second hyperpolarizability of para-disubstituted benzenes. MP2 and CCSD methods are used to determine the properties in question and, for 4-aminobenzaldehyde, we estimate the nuclear relaxation and electronic contribution to the longitudinal first hyperpolarizability at the CCSD(T)/aug-cc-pVTZ level of theory. This Letter demonstrates the importance of anharmonic contributions encompassed in the nuclear relaxation first and second hyperpolarizability. Moreover, it also points up the weakness of the double harmonic model which, in some instances, yields the incorrect sign of the vibrational contribution.

  • 122908.
    Zaleśny, Robert
    et al.
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Tian, Guangjun
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Hättig, C.
    Bartkowiak, W.
    Ågren, Hans
    KTH, Skolan för bioteknologi (BIO), Teoretisk kemi och biologi.
    Toward assessment of density functionals for vibronic coupling in two-photon absorption: A case study of 4-nitroaniline2015Ingår i: Journal of Computational Chemistry, ISSN 0192-8651, E-ISSN 1096-987X, Vol. 36, nr 15, s. 1124-1131Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, we predict vibronic two-photon absorption (TPA) spectra for 4-nitroaniline in vacuo. The simulations are performed using density functional theory and the approximate second-order coupled-cluster singles and doubles model CC2. Thereby we also demonstrate the possibility of simulations of vibronic TPA spectra with ab initio wavefunction methods that include electron correlation for medium-sized systems. A special focus is put on the geometric derivatives of the second-order transition moment and the dipole moment difference between the charge-transfer excited state and the ground state. The results of CC2 calculations bring new insight into the vibronic coupling mechanism in TPA spectra of 4-nitroniline and demonstrate that the mixed term is quite large and that it also exhibits a negative interference with the Franck-Condon contribution. CC2 method and several exchange-correlation functionals are used to predict vibronic two-photon absorption spectra of 4-nitroaniline.

  • 122909.
    Zalubovskis, Raivis
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Flexibility – a tool for chirality control in asymmetric catalysis2006Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This thesis deals with the design and synthesis of ligands for asymmetric catalysis: palladium catalyzed allylic alkylations, and rho-dium and iridium catalyzed hydrogenations of olefins.

    Chirally flexible phosphepine ligands based on biphenyl were synthesized and their properties were studied. The rotation barrier for configurationally flexible phosphepines was determined by NMR spectroscopy. The ratio of the atropisomers was shown to depend on the group bound to phosphorus. Only complexes with two homochiral ligands bound to the metal center were observed upon complexation with Rh(I). It was shown that one diastereomer of the flexible ligand exhibits higher activity but lower selectivity than its diastereomer in the rhodium catalyzed hydrogenation of methyl alfa-acetamidocinnamate. These ligands were also tested in nickel catalyzed silabora-tions.

    Chiral P,N-ligands with pseudo-C2 and pseudo-CS symmetry based on pyrrolidines-phospholanes or azepines-phosphepines were synthesized and studied in palladium catalyzed allylic alkylations. Semi-flexible azepine-phosphepine based ligands were prepared and their ability to adopt pseudo-C2 or pseudo-CS symmetry depending on the substrate in allylic alkylations was studied. It was shown on model allyl systems with flexible N,N-ligands that the ligand prefers CS-symmetry in compexes with anti-anti as well as syn-syn allyl moieties, but that for the latter type of complexes, according to computations, the configuration of the ligand is R*,R* in the olefin complexes formed after addition of a nucleophile to the allylic group.

    A preliminary investigation of the possibilities to use a su-pramolecular approach for the preparation of P,N-ligands with pseudo-C2 and pseudo-S symmetry was made. An N,N-ligand with C2 symmetry was prepared and its activity in palladium catalyzed ally-lic alkylation was studied.

    Pyridine-based P,N-ligands were tested in iridium catalyzed hy-drogenations of unfunctionalized olefins with good activities and se-lectivities. In order to attempt to improve the selectivity, ligands with a chirally flexible phosphepine fragment were prepared and applied in catalysis with promising results.

  • 122910.
    Zalubovskis, Raivis
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Bouet, Alexis
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Fjellander, Ester
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Constant, Samuel
    University of Geneva.
    Linder, David
    University of Geneva.
    Andreas, Fischer
    KTH, Skolan för kemivetenskap (CHE), Kemi, Oorganisk kemi (stängd 20110630).
    Lacour, Jérôme
    University of Geneva.
    Privalov, Timofei
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Moberg, Christina
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Self-adaptable Catalysts: Substrate-Dependent Ligand Configuration2008Ingår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 130, nr 6, s. 1845-1855Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Pd(II) allyl and Pd(0) olefin complexes containing the configurationally labile ligand 1,2-bis-[4,5dihydro-3H-dibenzo[c-e]azepino]ethane were studied as models for intermediates in Pd-catalyzed allylic alkylations. According to NMR and DFT studies, the ligand prefers C-s conformation in both eta(3)-1,3-diphenylpropenyl and eta(3)-cyclohexenyl Pd(II) complexes, whereas in Pd(0) olefin complexes it adopts different conformations in complexes derived from the two types of allyl systems in both solution and, as verified by X-ray crystallography, in the solid state. These results demonstrate that the Pd complex is capable of adapting its structure to the reacting substrate. The different structural preferences also provide an explanation for the behavior of 1,3-diphenyl-2-propenyl acetate and 2-cyclohexenyl acetate in Pd-catalyzed allylic alkylations using pseudo-C-2 and pseudo-C-s symmetric ligands.

  • 122911.
    Zalubovskis, Raivis
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Fjellander, Ester
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Szabó, Zoltán
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Moberg, Christina
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Stereochemical Control of Chirally Flexible Phosphepines2007Ingår i: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, Vol. 2007, nr 1, s. 108-115Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The barriers to interconversion of the two enantiomeric atropisomers of 6-methoxy-6,7-dihydro-5H-dibenzo[c,e]phosphepine and that of the diastereomeric forms of 6-(-)menthoxy-6,7-dihydro-3H-dibenzo[c,e]phosphepine were determined by NMR spectroscopical methods to be 19.3 and 18.5 kcalmol(-1), respectively, at 298 K. The ratio of the atropisomers was shown to depend on the group bound to phosphorus. Only complexes with two homochiral ligands bound to the each metal center were obtained upon reaction with [Rh(COD)(2)](+) BF4-. The Rh complexes catalyzed the hydrogenation of alpha-acetamidocinnamate. The major isomer of 6-(-)-menthoxy-6,7-dihydro-5H-dibenzo[c,e]phosphepine was found to exhibit higher activity but to afford a product with lower ee than its diastereomer.

  • 122912. Zalubovskis, Raivis
    et al.
    Hoermann, Esther
    Pfaltz, Andreas
    Moberg, Christina
    KTH, Skolan för kemivetenskap (CHE), Kemi, Organisk kemi.
    Iridium-catalyzed asymmetric hydrogenation of olefins using pyridine-phosphinites derived from the chiral pool2008Ingår i: ARKIVOC, ISSN 1424-6376, s. 58-66Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Cationic iridium complexes containing chiral pyridine-phosphinites, with their chirality derived from menthol or mandelic acid, were assessed in hydrogenations of trisubstituted non-functionalized olefins. Complexes with the new ligands showed high reactivity towards most of the olefins tested. The enantioselectivities varied with the structures of the substrate and the ligand. Best results were obtained in the hydrogenation of 3-hydroxy-2-methyl-1-phenylpropene using a ligand prepared from (-)-menthol, pyridyllithium and diphenylchlorophosphine (>99% conversion, 92% ee).

  • 122913.
    Zamaere, Bruce
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Hidell, Markus
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Sjödin, Peter
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    CVPN: A multi-homed VPN solution for remote patient monitoring2012Ingår i: 2012 IEEE 14th International Conference on e-Health Networking, Applications and Services, Healthcom 2012, IEEE , 2012, s. 279-285Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper addresses the challenges of reliably, and securely, extending a healthcare provider's network into the homes of its patients in order to provide Remote Patient Monitoring (RPM) services. It describes the Carenet Virtual Private Network (CVPN) solution, a multi-homed VPN solution implemented as a virtual device driver under Linux. We describe CVPN's architecture and implementation, motivating its design decisions. The initial experimental evaluation, of our proof-of-concept prototype, shows that CVPN's per packet overhead, forwarding delay, and fail-over time are reasonable for healthcare monitoring applications and time-sensitive synchronous communications.

  • 122914.
    Zamaere, Bruce
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Network Systems Laboratory (NS Lab).
    Lu, Da
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Network Systems Laboratory (NS Lab).
    Kullberg, Elis
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Network Systems Laboratory (NS Lab).
    On the design and implementation of a virtualized residential gateway2012Ingår i: Int. Conf. Consum. Electron., Commun. Networks, CECNet - Proc., 2012, s. 3349-3352Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents ongoing work in the realization of an open and functional next-generation Residential Gateway (RG). Our RG supports the deployment of third-party services through Operating System-Level (OS-Level) Virtualization, namely LXC Namespaces. Our experiences show that LXC Namespaces is capable of supporting a relatively high number of services with little performance overhead, even on modest hardware. In order to provide the proof of concept, we present a validating application from the healthcare domain, although the generic RG architecture is capable of supporting services from other service domains.

  • 122915.
    Zamaere, Bruce
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikation: Infrastruktur och tjänster (Stängd 20120101), Telekommunikationssystem, TSLab (stängd 2012-01-01).
    Sjödin, Peter
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikation: Infrastruktur och tjänster (Stängd 20120101), Telekommunikationssystem, TSLab (stängd 2012-01-01).
    Pehrson, Björn
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikation: Infrastruktur och tjänster (Stängd 20120101), Telekommunikationssystem, TSLab (stängd 2012-01-01).
    The CareNet residential gateway: A conceptual overview2010Ingår i: 2010 IEEE International Symposium on "A World of Wireless, Mobile and Multimedia Networks", WoWMoM 2010 - Digital Proceedings, IEEE , 2010, s. 5534980-Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a high-level overview of the CareNet Home Extension Project that aims to provide support for home-based healthcare for the elderly and outpatients. Details of a home networking environment based on a virtualized Residential Gateway (RG) are provided. The RG architecture is modular and scalable supporting the dynamic provision of third party services. This accommodates multiple independent stakeholders representing healthcare providers, Internet Services Providers (ISPs), and home automation system builders among others. Interoperability is guaranteed through adherence to open standards. Initial mechanisms facilitating the integration and consolidation of in-home systems, whilst providing a flexible framework for autonomous management, are described. This addresses issues of management and configuration of complex environments by individuals with little or no technical expertise. Finally, details of an initial implementation, in terms of architectural descriptions and enabling technological components, are outlined.

  • 122916.
    Zaman, Abdul
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Implementation and Performance Analysis of Information Communication between Traffic Simulation and Emission Estimation Systems2009Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Transport är en av de snabbt växande områden och i direkt samband med den sociala ekonomiska tillväxten i ett land. Och samtidigt är det en av de största källorna till utsläpp produktion, som har en enorm påverkan på den globala miljön och alla levande varelser. För närvarande använder metoder för skattning av utsläpp är mycket dyra och endast använda en eller två gånger per år. Men vi kan beräkna utsläppen i realtid med hjälp av trak simulator tillsammans med uppskattning system.

    Målet med detta examensarbete är att utveckla prestanda effektiv kommunikationsplattform mellan KTH-TPMA trak simulator och uppskattning för att mäta online utsläpp. För att bygga upp den kommunikationsplattform Olika simuleringsmodeller, arkitektur av KTH-TPMA trak simulator (dvs objekt hierarki och relationer, olika objekt interaktioner modeller händelse hantering mekanismen, och objektet uppdatera huvudmän), kommunikation middleware för heterogena miljöer, och olika uppskattning modeller studeras och undersökas. Meddelandet plattform genomförs med hjälp av CORBA och SOA (dvs. Web Service). I CORBA, synkron och asynkron (dvs uppskjutna synkron) kommunikationsmetoder genomförs. Traken simulator kan utbyta information på tre olika sätt, det vill säga enskilda, insamling och tråd meddelande lägen.

    För att ta reda på det optimala sättet mellan dessa två ansökningar olika fordon efterfrågan och vägnätet kongurationer används för att mäta kommunikation temne. Och utvärdera dessa kommunikation gånger för att ta reda på effektiv kommunikation metod. Efter utvärdering nner vi att CORBA asynkron kommunikation är det mest effektiva avseende på fjärrkontrollen meddelande temne. Men synkron kommunikation är bättre för exakt utsläppsvärdet.

  • 122917.
    Zaman, Atiq
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE).
    Comparative study of municipal solid waste treatment technologies using life cycle assessment method2012Ingår i: Sustainable Solid Waste Management, Apple Academic Press , 2012, s. 1-14Kapitel i bok, del av antologi (Övrigt vetenskapligt)
    Abstract [en]

    The aim of the study is to analyze three different waste treatment technologies by life cycle assessment (LCA) tool. Sanitary landfill, incineration, and gasification-pyrolysis of the waste treatment technologies are studied in SimaPro software based on inputoutput materials flow. SimaPro software has been applied for analyzing environmental burden by different impact categories. All technologies are favorable to abiotic and ozone layer depletion due to energy recovery from the waste treatment facilities. Sanitary landfill has the significantly lower environmental impact among other thermal treatment while gases are used for fuel with control emission environment. However, sanitary landfill has significant impact on photochemical oxidation, global warming, and acidification. Among thermal technology, pyrolysis-gasification is comparatively more favorable to environment than incineration in global warming, acidification, eutrophication, and eco-toxicity categories. Landfill with energy recovery facilities is environmentally favorable. However, due to large land requirement, difficult emission control system and long time span, restriction on land filling is applying more in the developed countries. Pyrolysis-gasification is more environmental friendly technology than incineration due to higher energy recovery efficiency. The LCA is an effective tool to analyze waste treatment technology based on environmental performances.

  • 122918.
    Zaman, Atiq Uz
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE).
    Comparative study of municipal solid waste treatment technologies using life cycle assessment method2010Ingår i: International Journal of Environmental Science and Technology, ISSN 1735-1472, Vol. 7, nr 2, s. 225-234Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The aim of the study is to analyze three different waste treatment technologies by life cycle assessment tool. Sanitary Landfill, Incineration and gasification-pyrolysis of the waste treatment technologies are studied in SimaPro software based on input-output materials flow. SimaPro software has been applied for analyzing environmental burden by different impact categories. All technologies are favorable to abiotic and ozone layer depletion due to energy recovery from the waste treatment facilities. Sanitary landfill has the significantly lower environmental impact among other thermal treatment while gases are used for fuel with control emission environment. However, sanitary landfill has significant impact on photochemical oxidation, global warming and acidification. Among thermal technology, pyrolysis-gasification is comparatively more favorable to environment than incineration in global warming, acidification, eutrophication and eco-toxicity categories. Landfill with energy recovery facilities is environmentally favorable. However, due to large land requirement, difficult emission control system and long time span, restriction on land filling is applying more in the developed countries. Pyrolysis-gasification is more environmental friendly technology than incineration due to higher energy recovery efficiency. Life cycle assessment is an effective tool to analyze waste treatment technology based on environmental performances.

  • 122919.
    Zaman, Atiq Uz
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö.
    Miliutenko, Sofiia
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Samhällsplanering och miljö, Miljöstrategisk analys.
    Nagapetan, Veranika
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik.
    Green marketing or green wash?: A comparative study of consumers' behavior on selected Eco and Fair trade labeling in Sweden2010Ingår i: Journal of Ecology and the Natural Environment, ISSN 2006-9847, E-ISSN 2006-9847, Vol. 2, nr 6, s. 104-111Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Green marketing is in the focus of present marketing strategy due to the pressure that comes from inclined environmental awareness in the global climate change. Different initiatives have been considered to support environmental programme and practices and one of the meaningful business initiatives is eco or fair trade labeling. Eco-label provides the information of product contribution in the context of environmental burden to the consumers. Different label initiatives are available in the present business market as a provider of ‘white goods’, however, the basic principles of the label initiative are ignored in most of the business practices. The study compared eight selected eco-brands which were used on the Swedish market. Comparison was based on environmental justice and ecosystem services perspectives. The study showed that most of the eco brands do not comply with environmental justice and ecosystem services in their label policy initiatives. Moreover, there is a gap between policy and practices. Questionnaire survey showed that environment is an important criterion for consumers while purchasing consumer products. Eco-label is an important tool; however, this tool is not communicating to consumers to its expected role.

  • 122920. Zamani, A.
    et al.
    Moubah, R.
    Ahlberg, M.
    Stopfel, H.
    Arnalds, U. B.
    Hallén, Anders
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Hjörvarsson, B.
    Andersson, G.
    Jönsson, P. E.
    Magnetic properties of amorphous Fe93Zr7 films: Effect of light ion implantation2015Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 117, nr 14, artikel-id 143903Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Curie temperature (T<inf>c</inf>) of amorphous FeZr alloys can be greatly enhanced by doping with light elements. In this investigation, ion implantation is used to dope Fe<inf>93</inf>Zr<inf>7</inf> thin films with H, He, B, C, and N. Extended X-ray absorption fine structure measurements confirm that the amorphous structure is preserved upon implantation for all samples, except for the N-implanted sample which is partially crystallized. The Curie temperature increases from 124 K for the pristine FeZr sample to about 400 K for the (FeZr)B<inf>0.11</inf> sample. The increase of T<inf>c</inf> is proportional to the increase in the average Fe-Fe distance, which allows us to conclude that the dominant cause of the T<inf>c</inf> enhancement of amorphous Fe<inf>93</inf>Zr<inf>7</inf> upon doping is a volume effect.

  • 122921. Zamani, Atieh
    Antimony implanted strained Si for nMOSFET applications2009Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Incorporation of implanted antimony (Sb) in strained-silicon (s-Si) formed on relaxed-SiGe virtual substrates (10 and 30% Ge) has been studied. The implantation doses were 5×1013- 5×1014 cm-2 with an energy of 20 keV. The activation of dopant was performed by an rapid thermal annealing (RTA) treatment at 700 and 800 °C for 30 sec. Projected range of this implantation is about 20 nm which was also confirmed by different techniques. The layers were analyzed in terms of strain relaxation, sheet resistance, thermal stability, defect generation and dopant incorporation. X-ray diffraction (XRD), high-resolution reciprocal lattice mapping (HRRLM), transmission electron microscopy (TEM), secondary ion mass spectrometry (SIMS), Rutherford backscattering (RBS), four-probe measurements and Hall measurements were applied as characterization tools. This work demonstrates that the Sb incorporation in Si has improved in the presence of strain. The strain amount in s-Si does not alter after implantation or subsequent thermal treatment for dopant activation. The Sb-implanted s-Si layer on Si0.70Ge0.30 virtual substrate (5×1014 cm-2 700 °C, 30 sec RTA) demonstrated substitutional Sb concentration of 2.5×1020cm-3 where the same dose for a Si reference sample could only show 1×1020 cm-3. The fraction of active-to-atomic concentration of Sb-implanted Si was estimated nearly to 90%. HRTEM micrographs of Sb-implanted annealed samples illustrate almost defect-free material.

  • 122922. Zamani, Atieh
    et al.
    Hallén, Anders
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Integrerade komponenter och kretsar.
    Nordblad, Per
    Andersson, Gabriella
    Hjörvarsson, Björgvin
    Jönsson, Petra E.
    Tuning magnetic properties by hydrogen implantation in amorphous Fe100-xZrx thin films2013Ingår i: Journal of Magnetism and Magnetic Materials, ISSN 0304-8853, E-ISSN 1873-4766, Vol. 346, s. 138-141Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Thin films of amorphous Fe100-xZrx (x=7.6-12.9 at%) were synthesized by dc-magnetron sputtering. Samples with compositions of x=11.6 and 12.0 at% were hydrogenated by implantation. The Curie temperature increases with hydrogen content from 232 K for as-grown Fe88Zr12 to 370 K for a sample hydrogenated to 31 at%. The coercivity decreases dramatically upon hydrogenation, yielding films with tunable transition temperatures and soft magnetic properties.

  • 122923.
    Zamani, Leila
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Methods for structural studies of an antibody, screening metabolites in rat urine and analysis of spent cell cultivation media using LC/ESI-MS and chemometrics2009Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This thesis describes bioanalytical methods for generating fingerprints of biological systems for extracting relevant information with (protein) drugs in focus. Similarities and differences between samples can reveal the hidden relevant information, which can be used to optimize the production and facilitate the quality control of such protein drugs during their development and manufacture. Metabolic fingerprinting and multivariate data analysis (MVDA) can also facilitate early diagnosis of diseases and the effects and toxicity of drugs.

    Currently, several protein drugs are available on the global market. Nevertheless, despite, the success of such biotherapeutics significant challenges remain to be overcome in maintaining their stability and efficacity throughout their production cycle and long-term storage. The native structure and functional activity of therapeutic proteins is affected by many variables from production to delivery, incl. variables assoc. with conditions in bioreactors, purification, storage and delivery. Thus, part of the work underlying this thesis focused on structural analysis of a protein drug using chemical labeling, peptide mapping, and evaluation of the charge state distributions of the whole protein generated by ESI. The other part focuses on non-targeted metabolomics with a view to optimizing the cell cultivation process and assessment of the drug’s toxicity. A combination of appropriate analytical methods and MVDA is needed to find markers that can facilitate optimization of the cultivation system and expression of the target proteins in early stages of process development. Rapid methods for characterizing the protein drugs in different stages of the process are also required for quality control.

    In order to obtain high quality fingerprints analytical separation techniques with high resolution (such as HPLC or UHPLC) and sensitive analytical detection techniques (such as ESI, quadrupole or TOF MS) have been used, singly or in combination.

  • 122924.
    Zamani, Leila
    et al.
    Department of Analytical Chemistry, Stockholm University.
    Andersson, Fredrik O.
    Edebrink, Per
    Yang, Yang
    Jacobsson, Sven P.
    Conformational studies of a monoclonal antibody, IgG1, by chemical oxidation: Structural analysis by ultrahigh-pressure LC-electrospray ionization time-of-flight MS and multivariate data analysis2008Ingår i: Analytical Biochemistry, ISSN 0003-2697, E-ISSN 1096-0309, Vol. 380, nr 2, s. 155-163Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We describe the development of a method in which protein oxidation by H2O2 followed by ultrahigh-pressure liquid chromatography (UHPLC) coupled with electrospray ionization time-of-flight mass spectrometry (ESI-ToFMS) and multivariate analysis are used to detect alterations in conformational states of proteins. In the study reported here, an IgG1 monoclonal antibody in native and denatured conformational states was oxidized by treatment with hydrogen peroxide. Peptide fragments generated by tryptic digestion were then analyzed by UHPLC-ESI-ToFMS. After reducing noise and extracting peaks from the LC-MS data using MzExplorer, software developed in-house and based on Matlab, we were able to distinguish peptides arising from the native and denatured states of the oxidized protein by principal component analysis. Peptides containing residues, which are inclined to undergo oxidation, such as methionine, are founded to be particularly important in this approach. We believe that the methodology could facilitate attempts to characterize the conformational states of recombinant monoclonal antibodies and other proteins.

  • 122925. Zamani, Leila
    et al.
    Landegren, Emma
    Hedin, Eva
    Hagman, Anders
    Chatzissavidou, Nathalie
    Jacobsson, Sven P.
    Extracellular metabolic fingerprinting of spent mammalian cell culture medium analysis in relation to the quality of an expressed recombinant proteinManuskript (preprint) (Övrigt vetenskapligt)
  • 122926.
    Zamani, Leila
    et al.
    Department of Analytical Chemistry, Stockholm University.
    Lindholm, Jessica
    Ilag, Leopold L.
    Jacobsson, Sven P.
    Discrimination among IgG1-Κ monoclonal antibodies produced by two cell lines using charge state distributions in nanoESI-TOF mass spectra2009Ingår i: Journal of the American Society for Mass Spectrometry, ISSN 1044-0305, E-ISSN 1879-1123, Vol. 20, nr 6, s. 1030-1036Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Charge state distributions (CSDs) of proteins in nanoESI mass spectra are affected by the instrumental settings and experimental conditions, in addition to the conformations of the proteins in the analyzed solutions. In the presented study, instrumental and experimental parameters-the desolvation gas flow rate, temperature, pH, buffer (ammonium acetate), and organic modifier (methanol) concentrations-were optimized according to a reduced central composite face experimental design to maximize the separation of CSDs of monoclonal IgG1-kappa antibodies produced by two production systems (CHO and GS-NS0 cell lines). Principal component analysis and Fisher linear discriminant analysis were then used to reduce the dimensions of the acquired dataset and quantify the separation of the protein classes, respectively. The results show that the IgG1-kappa molecules produced by the two production systems can be clearly distinguished using the described approach, which could be readily applied to other proteins and production systems.

  • 122927. Zamani, Leila
    et al.
    Lundqvist, Magnus
    Zhang, Ye
    Åberg, Magnus
    Edfors, Fredrik
    Bidkhori, Gholamreza
    Lindahl, Anna
    Mie, Axel
    Mardinoglu, Adil
    Rockberg, Johan
    Chotteau, Veronique
    High cell density perfusion culture has a maintained exoproteome and metabolomeManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Chinese hamster ovary (CHO) cells are the workhorse to produce recombinant proteins in the biopharmaceutical industry using mammalian cells and are commonly cultured in either fed-batch or perfusion mode. The optimization of the complex biological systems used in such processes is extremely challenging. Multi-omics approaches can reveal otherwise unknown characteristics of these systems and identify culture parameters that can be manipulated to optimize the cultivation process. Here we have ap- plied both metabolomic and proteomic profiling to a monoclonal antibody (mAb) production operated in perfusion mode to explore how cell biology and reactor environment change as the cell density reaches ≥ 200 x 106 cells/mL. The extracellular metabolic composition obtained in perfusion mode was also com- pared to fed-batch, which showed a more stable profile for perfusion despite a far larger range of viable cell densities. The proteomics data showed an increase of structural proteins as the cell density increased, and both the proteomic and metabolic results showed signs of oxidative stress and changes in glutathione metabolism at very high cell densities. The methodology presented herein could be a powerful tool for optimizing cultivation processes and recombinant protein production.

  • 122928.
    Zamani, Leila
    et al.
    KTH, Skolan för bioteknologi (BIO), Industriell bioteknologi.
    Zhang, Ye
    KTH, Skolan för bioteknologi (BIO), Industriell bioteknologi.
    Aberg, Magnus
    Lindahl, Anna
    Mie, Axel
    Chotteau, Veronique
    KTH, Skolan för bioteknologi (BIO), Industriell bioteknologi.
    Metabolic footprinting of CHO cell culture bioprocess data in fed-batch and perfusion mode using LC-MS data and multivariate analysisManuskript (preprint) (Övrigt vetenskapligt)
  • 122929. Zamani, Mohsen
    et al.
    Bottegal, Giulio
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Anderson, Brian D. O.
    On the Zero-Freeness of Tall Multirate Linear Systems2016Ingår i: IEEE Transactions on Automatic Control, ISSN 0018-9286, E-ISSN 1558-2523, Vol. 61, nr 11, s. 3606-3611Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this technical note, tall discrete-time linear systems with multirate outputs are studied. In particular, we focus on their zeros. In systems and control literature zeros of multirate systems are defined as those of their corresponding time-invariant systems obtained through blocking of the original multirate systems. We assume that blocked systems are tall, i.e., have more outputs than inputs. It is demonstrated that, for generic choice of the parameter matrices, linear systems with multirate outputs generically have no finite nonzero zeros. However, they may have zeros at the origin or at infinity depending on the choice of blocking delay and the input, state and output dimensions.

  • 122930. Zamani, Mohsen
    et al.
    Bottegal, Giulio
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Anderson, Brian D.O.
    On the properties of linear multirate systems with coprime output rates2013Ingår i: 2013 IEEE 52nd Annual Conference on Decision and Control (CDC), IEEE conference proceedings, 2013, s. 2734-2739Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper studies discrete-time linear systems with multirate outputs, assuming that two measured output streams are available at coprime rates. In the literature this type of system, which can be considered as periodic timevarying, is commonly studied in its blocked version, since the well-known techniques of analysis developed for linear timeinvariant systems can be used. In particular, we focus on some structural properties of the blocked systems and we prove that, under a generic setting i.e. for a generic choice of parameter matrices, the blocked systems are minimal when the underlying multirate system is defined using a minimal dimension system. Moreover, we focus on zeros of tall blocked systems i.e. blocked systems with more outputs than inputs. In particular, we study those cases where the associated system matrix attains fullcolumn rank. We exhibit situations where they generically have no finite nonzero zeros.

  • 122931.
    Zamani, Sam
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Investigation of using a PRET processor on a low-cost, low- power FPGA2016Självständigt arbete på grundnivå (yrkesexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Mixed-criticality is a current trend in real-time embedded systems, where software tasks are integrated onto fewer hardware platforms. The basic idea is to use one processor to execute multiple tasks with differing requirements of certification, importance or safety. In systems where time is an important key factor the behavior of that system must be predictable at all times, which is hard to achieve when optimizations made to achieve good performance lower predictability at the same time. In 2007 Stephen A. Edwards and Edward A. Lee made a case for the precision-timed (PRET) machine as a solution, arguing that temporal behavior is to be treated equal to functional behavior. One of those PRET machines is FlexPRET, which is the processor we are studying in this thesis.

    This thesis aims to study the generation, synthesis and programming of FlexPRET, a finegrained multithreaded RISC-V based PRET processor developed at UC Berkeley. This is part of a larger-scale project to port FlexPRET to be used as a node processor in a NoC mesh generated by ForSyDe, a programming methodology developed at the Royal Institute of Technology.Previous synthesis of FlexPRET has been done on FPGAs from the Virtex-5 and Spartan-6 families by Xilinx. The FPGA used for this thesis is from the Cyclone IV family by Altera.

    Evaluation of the synthesis results have been performed by running a real-time application on FlexPRET that blinks LEDs on the Altera DE2-115 board.

  • 122932. Zamanizadeh, E.
    et al.
    Gomes, J.
    Bioucas-Dias, J. M.
    Karasalo, Ilkka
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Performance analysis of model-based localization of high-frequency acoustic sources in 3D2013Ingår i: OCEANS 2013 MTS/IEEE Bergen: The Challenges of the Northern Dimension, 2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    A robust model-based source localization (MBSL) scheme for 3D positioning of high-frequency underwater acoustic (UWA) transmitters, as well as performance assessment of 3D speed vector estimation of the acoustic source, deploying two linear receiver arrays, is developed and evaluated. In addition, this paper presents the sensitivity evaluation of MBSL to uncertainties involved in environmental parameters, including the effects of sound speed profile and bathymetry mismatches. The results presented here pertain to the general framework of inferring side information concerning an UWA link from the environmental signature imprinted on waveforms by the propagation medium. The presented algorithms directly operate on estimated linear time-varying UWA channel responses, represented as 3-dimensional delay-Doppler-depth functions (DDDF). Estimation of DDDF coefficients is achieved jointly for all receivers deployed at different depths using Basis-Pursuit (BP) tools, which can efficiently handle sparse unconstrained ℓ2 - ℓ1 minimization, and directly operate on the complex signals of baseband models. To extract delay/Doppler information related to each path from the DDDF representation, an efficient energy-based scheme is developed to detect and label wavefronts using clustering techniques inspired by image processing.

  • 122933. Zambaux, J. A.
    et al.
    Manickam, Louis
    Meignen, R.
    Ma, W. M.
    KTH.
    Bechta, Sevostian
    KTH, Skolan för teknikvetenskap (SCI), Fysik, Kärnkraftssäkerhet.
    Picchi, S.
    Study on thermal fragmentation characteristics of a superheated alumina droplet2018Ingår i: Annals of Nuclear Energy, ISSN 0306-4549, E-ISSN 1873-2100, Vol. 119, s. 352-361Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the frame of the European Commission FP7 SAFEST project, IRSN proposed to experimentally investigate the steam explosion triggering mechanisms of a superheated alumina droplet falling into water, through a set of experiments in the Micro Interactions in Steam Explosion Energetics facility (MISTEE) at KTH. Since thermal fragmentation is considered to be a likely process for the triggering of Steam Explosions in the KROTOS tests (performed at CEA) with alumina, the ability of a single droplet of such material to undergo thermally induced fine fragmentation is studied on the MISTEE facility with a close-up visualization. A series of experiments were conducted, where droplets of molten alumina were discharged into a water pool and potentially exposed to a small pressure wave. The intense interactions were recorded with a high-speed camera along with the pressure in the droplet vicinity. The ability of alumina to undergo thermal fragmentation is expected to be firstly contingent on the stability of the vapour film enshrouding the melt droplet. The water and melt temperatures may then play a crucial role on the vapour film stability, and therefore on the observation of a steam explosion. Indeed, under high to moderate water sub-cooling conditions, experimental observations indicate that fine fragmentation of the melt can occur when the droplet is exposed to even a weak pressure wave, in the range of 0.15 MPa. In contrast, melt fine fragmentation is suppressed at low water sub-cooling conditions (less than 30 °C), where the formation of a thick vapour film (and large wake) is observed, and which is probably too stable to be destabilized by the weak pressure wave. The effect of the melt temperature on thermal fragmentation is also assessed. This parameter influences the solidification of the droplet and the strength of the explosion as it determines the available heat energy. In the present conditions, fine fragmentation of melt occurred even at quite low melt superheat (≈60 °C). For a high melt superheat (above 200 °C) a very energetic spontaneous steam explosion was observed. A physical analysis on the debris particles acquired indicates a mass median diameter of ≈100 µm, comparable to the one observed in the KROTOS alumina experiments. The MISTEE experimental results are finally used to assess the heat and mass transfer modelling of the coolant during the fragmentation process in the FCI code MC3D.

  • 122934.
    Zambelli, Martina
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik.
    Posture regulation for unicycle-like robots with prescribed performance guarantees.2013Studentarbete övrigt, 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    This thesis focuses on control of nonholonomic system with particular reference to the unicycle-like robots. These are common examples of WMRs (Wheeled Mobile Robots), increasingly present in industrial and service robotics, particularly when exible motion capabilities are required. The major objective of this study is to solve the regulation problem for the unicycle model while guaranteeing prescribed performance. Dierent controllers based on either polar coordinates or time-varying laws are proposed. The main contribution is the combination of the standard control laws (both with polar coordinates and time-varying laws) that allow to achieve posture regulation for the unicycle model, with the prescribed performance control technique that imposes time-varying constraints to the system coordinates. The study also illustrates two dierent approaches to bind linear or angular coordinates, one based on a particular error transformation, and the other arising from a specific potential function.

    Simulations conrm the eectiveness of the proposed solutions.

  • 122935.
    Zambelli, Martina
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för datavetenskap och kommunikation (CSC), Centra, Centrum för Autonoma System, CAS. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Karayiannidis, Yiannis
    KTH, Skolan för datavetenskap och kommunikation (CSC), Datorseende och robotik, CVAP. KTH, Skolan för datavetenskap och kommunikation (CSC), Centra, Centrum för Autonoma System, CAS.
    Dimarogonas, Dimos V.
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för datavetenskap och kommunikation (CSC), Centra, Centrum för Autonoma System, CAS. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Posture regulation for unicycle-like robots with prescribed performance guarantees2015Ingår i: IET Control Theory & Applications, ISSN 1751-8644, E-ISSN 1751-8652, Vol. 9, nr 2, s. 192-202Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study aims to address the regulation problem for the unicycle model while guaranteeing prescribed performance. Different controllers based either on polar coordinates or time-varying laws are proposed. The main contribution is the combination of the standard control laws that allow to achieve posture regulation for the unicycle, with the prescribed performance control technique that imposes time-varying constraints to the system coordinates. To apply prescribed performance to the unicycle system which is subject to a non-holonomic constraint, the authors design a specific transformation function that is instrumental in the proof of asymptotic convergence with prescribed guaranties.

  • 122936. Zambrano, Noelia
    et al.
    Tyrode, Eric
    KTH, Skolan för kemivetenskap (CHE), Kemi, Ytkemi.
    Mira, Isabel
    Marquez, Laura
    Rodriguez, Maria-Patricia
    Salager, Jean-Louis
    Emulsion Catastrophic Inversion from Abnormal to Normal Morphology. 1. Effect of the Water-to-Oil Ratio Rate of Change on the Dynamic Inversion Frontier2003Ingår i: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 42, nr 1, s. 50-56Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The rate of addn. of the internal phase affects the catastrophic inversion of emulsions in the direction of change from abnormal to normal morphol. At a low addn. rate, the inversion takes place after a small amt. of the internal phase is added, and it happens through the occurrence of multiple emulsion morphol. At a high addn. rate, the inversion appears to be delayed, and it takes place without the occurrence of a multiple emulsion. [on SciFinder (R)]

  • 122937. Zambrano, P.
    et al.
    Smale, M.
    Maldonado, J. H.
    Mendoza, Sandra L.
    KTH.
    Unweaving the threads: The experiences of female farmers with biotech cotton in Colombia2012Ingår i: Agbioforum, ISSN 1522-936X, E-ISSN 1522-936X, Vol. 15, nr 2, s. 125-137Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Although the literature on gender in agriculture is extensive, gender has been under studied in the published literature about biotech crops in developing countries. To explore whether gender affects access to and use of biotech cotton, we developed and tested a participatory, qualitative approach. Despite the perception that women participate little in cotton production in Colombia, some women manage their own plots, and many share production responsibilities with their spouses. Men and women perceive the costs and benefits of biotech cotton differently. Female farmers who managed their own plots stated that they preferred insect-resistant varieties over conventional varieties primarily because these reduce the number of laborers they must hire to spray pesticides, a task performed solely by men. Both male and female farmers identified the lack of adequate and timely information about biotech cotton as a major disadvantage, but the problem appeared to be more limiting for female farmers.

  • 122938. Zammarano, Mauro
    et al.
    Krämer, Roland H
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Harris, Jr
    Ohlemiller, J
    Shields, R
    Rahatekar, S
    Lacerda, Silvia
    Gilman, W
    Flammability reduction of flexible polyurethane foams via carbon nanofiber network formation2008Ingår i: Polymers for Advanced Technologies, ISSN 1042-7147, E-ISSN 1099-1581, Vol. 19, nr 6, s. 588-595Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Untreated polyurethane flexible foams (PUFs) are prone to rapid fire growth due to their low density and low thermal conductivity. Furthermore, the low viscosity of the decomposition products generates severe dripping that increases the fire hazard related to the combustion of PUFs. In fact, this downward flow of flaming liquid often results in a pool-fire that promotes flame propagation and boosts the rate of heat release (HRR) due to a significant increase in the burning area and to feed-back between the flame on the pool-fire and the residual foam. In this work the effect of nartoparticles, i.e., clays and carbon nanofibers (CNFs), on the HRR is investigated with special attention given to melt dripping. A modified cone calorimeter test has been developed for this purpose. It is shown that CNFs form an entangled fiber network which eliminates melt dripping and decreases the HRR.

  • 122939. Zamocky, M.
    et al.
    Hallberg, Martin
    KTH, Tidigare Institutioner (före 2005), Bioteknologi.
    Ludwig, R.
    Divne, Christina
    KTH, Tidigare Institutioner (före 2005), Bioteknologi.
    Haltrich, D.
    Ancestral gene fusion in cellobiose dehydrogenases reflects a specific evolution of GMC oxidoreductases in fungi2004Ingår i: Gene, ISSN 0378-1119, E-ISSN 1879-0038, Vol. 338, nr 1, s. 1-14Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Cellobiose dehydrogenases (CDHs) are extracellular hemoflavoenzymes that are thought to be involved in the degradation of two of the most abundant biopolymers in the biosphere, cellulose and lignin. To date, these enzymes, consisting of a cytochrome domain and a flavin domain, have been detected and sequenced exclusively in the kingdom of fungi. Independent phylogenetic analyses of two distinct domains of CDH genes reveal that they evolved in parallel as fused genes. Whereas the cytochrome domains are unique sequence motifs, the flavin domains clearly belong to the glucose-methanol-choline (GMC) oxidoreductase family-an evolution line of widespread flavoproteins extending from the Archae to higher eukaryotes. The most probable unrooted phylogenetic tree obtained from our analysis of 52 selected GMC members reveals five principal evolutionary branches: cellobiose dehydrogenase, cholesterol oxidase (COX), hydroxynitrile lyase, alcohol oxidase (AOX)/glucose oxidase (GOX)/choline dehydrogetrase, and a branch of dehydrogenases with various specificities containing also an Archaeon open reading frame (ORF). Cellobiose dehydrogenases cluster with cholesterol oxidases and the clade of various specificities, whereas hydroxynitrile lyases are closely related to glucose oxidases, alcohol oxidases, and choline dehydrogenases. The results indicate that the evolutionary line from a primordial GMC flavoprotein to extant cellobiose dehydrogenases was augmented after an early acquisition of the cytochrome domain to form two distinct branches for basidiomycetes and ascomycetes. One ascomycetous evolutionary line of CDHs has acquired a carbohydrate-binding module (CBM) of type 1, the sequence of which is similar to that of corresponding domains in several glycosidases. This is the first attempt towards a comprehensive phylogenetic analysis of cellobiose dehydrogenases.

  • 122940. Zamocky, M.
    et al.
    Ludwig, R.
    Peterbauer, C.
    Hallberg, B. M.
    Divne, Christina
    KTH, Skolan för bioteknologi (BIO), Glykovetenskap.
    Nicholls, P.
    Haltrich, D.
    Cellobiose dehydrogenase - A flavocytochrome from wood-degrading, phytopathogenic and saprotropic fungi2006Ingår i: Current protein and peptide science, ISSN 1389-2037, E-ISSN 1875-5550, Vol. 7, nr 3, s. 255-280Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Cellobiose dehydrogenase, the only currently known extracellular flavocytochrome. is formed not only by a number of wood-degrading but also by various phytopathogenic fungi. This inducible enzyme participates in early events of lignocellulose degradation, as investigated in several basidiomycete fungi at the transcriptional and translational level. However, its role in the ascomycete fungi is not yet obvious. Comprehensive sequence analysis of CDH-encoding genes and their translational products reveals significant sequence similarities along the entire sequences and also a common domain architecture. All known cellobiose dehydrogenases fall into two related subgroups. Class-I members are represented by sequences from basidiomycetcs whereas class-II comprises longer, more complex sequences from ascomycete fungi. Cellobiose dehydrogenase is typically a monomeric protein consisting of two domains joined by a protease-sensitive linker region. Each larger (dehydrogenase) domain is flavin-associated while the smaller (cytochrome) domains are haem-binding. The latter shorter domains are unique sequence motifs for all currently known flavocytochromes. Each cytochrome domain of CDH can bind a single haem b as prosthetic group. The larger dehydrogenase domain belongs to the glucose-methanol-choline (GMC) oxidoreductase superfamily - a widespread flavoprotein evolutionary line. The larger domains can be further divided into a flavin-binding subdomain and a substrate-binding subdomain. In addition, the class-II (but not class-I) proteins can possess a short cellulose-binding module of type I at their C-termini. All the cellobiose dehydrogenases oxidise cellobiose, cellodextrins, and lactose to the corresponding lactones using a wide spectrum of different electron acceptors. Their flexible specificity serves as a base for the development of possible biotechnological applications.

  • 122941.
    Zamolo, Giovanni
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Architecture Designfor Compressed Sensing-Based Low Power Systems2016Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    In the Internet of Things scenario, a desirable feature of wireless sensors is the energy autonomy. However, the transmitter stage needs a great amount of energy to modulate and transmit the interested information. The power consumption can be improved using data compression algorithms: thereby, the total amount of the transmitted data is reduced, at expense of computational complexity. Alternatively, the recent compressed sensing technique can be applied on sparse signal instances, that is when most of the entries of the signal are zero or negligible in a fixed representation. Compressed sensing acquires directly the compressed information using nonadaptive measurements and it reconstructs the signal using non-linear algorithms. Each measurement contains information of the whole signal within a frame having a fixed length. As a result, the front-end architecture complexity is decreased at expense of the reconstruction. Moreover, thanks to the compressed sensing schemes, the sampling frequency can be far lower than the conventional Nyquist rate.This thesis investigates the applicability and the advantages of this technique for the electrocardiogram signal acquisition and for the ultra-wideband receiver; indeed, both signals can be considered sparse. The focus is on the reduction of the CS measurements for the impact on the hardware requirements. The optimal design parameters are defined for the CS-based systems, leading to a reduction of power consumption.During the simulations, a noisy electrocardiogram signal is acquired and reconstructed using different setups. More interest is made on the sparsity representation, the sampling frequency, and the compressed sensing frame length. The results show clearly that the signal is more sparse when it is represented using a Biorsplines wavelet function. Moreover, a trade-off between the sampling frequency and the signal length is needed and the performance is strongly influenced by the heart rate. It is convenient to use low sampling frequency, and high frame length: a valid performance is obtained using 350 Hz as sampling rate and frames of 1024 samples.Ultra-wideband technology is suitable for Internet of Things applications because the transmitter is easier to implement and it consumes less power if compared to the traditional narrow band transmitters. However, in fully digital receivers, the required Nyquist rate is high. In the ultra-wideband scenario, compressed sensing is an attractive solution in the receiver side for the capability of recovering the signal from a small number of measurements using sub-Nyquist sampling rate: using a parallel receiver the sampling rate can be one hundred times lower than the Nyquist one. Models of the ultra-wideband transmitter and receiver are developed and simulations are performed in different noisy scenarios. Therefore, practical design parameters are investigated, including the pulse bandwidth and the compressed sensing frame length. From the results, the 3.1 10.6 GHz band allows better performance. Moreover, this thesis suggests using short compressed sensing frame length in order to reduce the total amount of needed measurements.The thesis has been developed during an European exchange program in Stockholm, Sweden, at KTH, Royal Institute of Technology.

  • 122942. Zamolo, Giovanni
    et al.
    Mao, Jia
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Zou, Zhuo
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Zheng, Li-Rong
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Elektronik, Integrerade komponenter och kretsar.
    Power-Aware Optimization for CS-based IR-UWB System2016Ingår i: 2016 IEEE INTERNATIONAL CONFERENCE ON UBIQUITOUS WIRELESS BROADBAND (ICUWB2016), IEEE conference proceedings, 2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    Compressed sensing (CS) is an emerging technology that can be applied to impulse radio ultra-wideband (IR-UWB) receivers. CS represents an attractive solution for its capability of recovering a signal from a small number of measurements using sub-Nyquist sampling rate analog to digital converters (ADC). In this paper we investigate practical design parameters for low power CS based UWB system, including pulse bandwidth, number of measurements and frame length. Considering the FCC mask, three different pulses are compared in noisy environment in order to provide an optimal solution for high bit rate and low bit rate applications. Performance impact on number of measurements and frame length are also evaluated so that minimum numbers and length can be used for power saving.

  • 122943.
    Zamouche, Ahmed
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Mekatronik. KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Inbyggda styrsystem.
    Chammam, Oussama
    KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Mekatronik. KTH, Skolan för industriell teknik och management (ITM), Maskinkonstruktion (Inst.), Inbyggda styrsystem.
    För ett automatiserat återskapande av inbyggda systems funktionella arkitektur från källkod och produkt data2013Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    “För ett automatiserat återskapande av inbyggda systems funktionella arkitektur från källkod och produkt data” Den ökade komplexiteten i inbyggda system inom fordonsindustrin tillsammans med de striktare säkerhetsrestriktionerna som infördes av ISO26262 standarden, kräver bättre kunskap och kännedom om produktarkitekturen. Men, för befintliga produkter som inte var utvecklade enligt en väldefinierad arkitekturmodell, så måste en modell återhämtas. Syftet med detta examensarbete är att automatisera återhämtningen av funktionella arkitekturen för fordons inbyggda system, vilket är ett krav för många av ISO26262 aktiviteter. Detta examensarbete föreslår och beskriver två modeller för det inbyggda systemet i ett fordon, och visar dess användning för att bland annat generera användarvänliga vyer. Återhämtningen av modellerna sker genom att tolka den inbyggda C-koden och bearbeta fordonets data såsom inblandade styrenheter, deras adresser och CAN buss detaljerna. Två modeller har föreslagits för att fånga den återskapade informationen om inbyggda systemet i ett fordon: en produktmodell för inbyggda system och en mjukvaruarkitektur modell för den inbyggda mjukvaran. Produktmodellen är en enkel modell på det inbyggda systemet som bara inkluderar nödvändig hårdvaru- och mjukvaru-detaljer för att klara uppgiften att skapa denfunktionella arkitekturen. Den inbyggda mjukvaruarkitektur modellen härleds från produktmodellen. Den modellerar endast högnivå komponentbaserade mjukvarulagret i alla styrenheter tillsammans. Därmed så abstraheras all hårdvaruinformation inklusive mjukvaruallokering och CAN buss information. De föreslagna modellerna har framgångsrikt använts för att generera funktionella arkitekturen för ett par SCANIA lastbilar. Generering och återhämtningen av modellerna utfördes med hjälp av ett verktyg som utvecklades för detta ändamål. Vidare så har en standardiseringsmekanism från de föreslagna modellerna till AUTOSAR också tagits fram och presenterats. Standardiseringsmekanismen är rättfram när styrenhets kring utrustning inte beaktas i modellen. I framtiden bör sensorer och ställdon inkluderas i modellerna. En mer detaljerad studie av den inbyggda programvaruarkitektur modellen, beträffande databeroende, bör också genomföras för att ta itu med problemen rörande felaktiga data-flödesvägar vilka har träffats på i detta arbete. Dessa problem uppkommer vid steget för CAN buss abstraktion.

  • 122944.
    Zamovaro, A. M.
    et al.
    Research Institute on Health Sciences, University of Balearic Islands, Palma de Mallorca, Spain;Institute for Medical Psychology and Behavioral Neurobiology, University of Tübingen, Germany.
    Zatorre, R. J.
    International Laboratory for Brain, Music and Sound research (BRAMS), Montreal, Canada;McGill University–Montreal Neurological Institute, Neuropsychology and Cognitive Neuroscience, Montreal, Canada.
    Vuust, Peter
    Center for Music in the Brain, Department of Clinical Medicine, Aarhus University;The Royal Academy of Music Aarhus/Aalborg, Denmark.
    Friberg, Anders
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Tal, musik och hörsel, TMH.
    Birbaumer, Niels
    Institute for Medical Psychology and Behavioral Neurobiology, University of Tübingen, Germany;Wyss Center for Bio and Neuroengeneering, Chenin de Mines 9, 1202, Geneva, Switzerland.
    Kleber, Boris
    Institute for Medical Psychology and Behavioral Neurobiology, University of Tübingen, Germany;Center for Music in the Brain, Department of Clinical Medicine, Aarhus University;The Royal Academy of Music Aarhus/Aalborg, Denmark.
    Enhanced insular connectivity with speech sensorimotor regions in trained singers – a resting-state fMRI studyManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    The insula contributes to the detection and integration of salient events during goaldirected behavior and facilitates the interaction between motor, multisensory, and cognitive networks. Task-fMRI studies have suggested that experience with singing can enhance access to these resources. However, the long-term effects of vocal motor training on insula-based networks are currently unknown. In thisstudy, we used restingstate fMRI to explore experience-dependent differences in insula co-activation patterns between conservatory-trained singers and non-singers. We found enhanced insula connectivity in singers compared to non-singers with constituents of the speech sensorimotor network, including the cerebellum (lobule VI, crus 2), primary somatosensory cortex, the parietal lobes, and the thalamus. Moreover, accumulated singing training correlated positively with increased co-activation in bilateral primary sensorimotor cortices in the somatotopic representations of the larynx (left dorsal anterior insula, dAI) and the diaphragm (bilateral dAI)—crucial regions for motorcortical control of complex vocalizations—together with the thalamus (bilateral posterior insula/left dAI) and the left putamen (left dAI). The results of this study support the view that the insula plays a central role in the experience-dependent modulation of sensory integration within the vocal motor system, possibly by optimizing conscious and non-conscious aspects of salience processing associated with singing-related bodily signals.

  • 122945. Zampella, F.
    et al.
    De Angelis, Alessio
    KTH, Skolan för elektro- och systemteknik (EES), Signalbehandling. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Skog, Isaac
    KTH, Skolan för elektro- och systemteknik (EES), Signalbehandling. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Zachariah, Dave
    KTH, Skolan för elektro- och systemteknik (EES), Signalbehandling. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Jimenez, A.
    A constraint approach for UWB and PDR fusion2012Ingår i: 2012 International Conference on Indoor Positioning and Indoor Navigation, IPIN 2012 - Conference Proceedings, IEEE , 2012, s. 6418929-Konferensbidrag (Refereegranskat)
    Abstract [en]

    Pedestrian Dead-Reckoning (PDR) and Radio Frequency (RF) ranging/positioning are complementary techniques for position estimation but they usually locate different points in the body (RF in the head/hand and PDR in the foot). We propose to fuse the information from both navigation points using a constraint filter with an upper bound in the distance between the estimated positions of both sensors.

  • 122946.
    Zampogna, Giuseppe A.
    et al.
    Univ Genoa, Scuola Politecn, DICCA, Via Montallegro 1, I-16145 Genoa, Italy..
    Lacis, Ugis
    KTH, Skolan för teknikvetenskap (SCI), Mekanik. KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW.
    Bagheri, Shervin
    KTH, Skolan för teknikvetenskap (SCI), Mekanik. KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW.
    Bottaro, Alessandro
    Univ Genoa, Scuola Politecn, DICCA, Via Montallegro 1, I-16145 Genoa, Italy..
    Modeling waves in fluids flowing over and through poroelastic media2019Ingår i: International Journal of Multiphase Flow, ISSN 0301-9322, E-ISSN 1879-3533, Vol. 110, s. 148-164Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Multiscale homogenization represents a powerful tool to treat certain fluid-structure interaction problems involving porous, elastic, fibrous media. This is shown here for the case of the interaction between a Newtonian fluid and a poroelastic, microstructured material. Microscopic problems are set up to determine effective tensorial properties (elasticity, permeability, porosity, bulk compliance of the solid skeleton) of the homogenized medium, both in the interior and at its boundary with the fluid domain, and an extensive description is provided of such properties for varying porosity. The macroscopic equations which are derived by homogenization theory employ such effective properties thus permitting the computation of velocities and displacements within the poroelastic mixture for two representative configurations of standing and travelling waves.

  • 122947. Zampollo, M.
    et al.
    Madani, Hatef
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    Lundqvist, Per
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Tillämpad termodynamik och kylteknik.
    The role of heat pumps in smart grids2015Ingår i: Refrigeration Science and Technology, International Institute of Refrigeration, 2015, s. 3905-3913Konferensbidrag (Refereegranskat)
    Abstract [en]

    The spread of intermittent renewable energy sources and distributed generation units make load management an even more delicate aspect of energy system operations. Heat pump technology can provide a major contribution to energy system management once properly integrated in its infrastructure, as foreseen by the Smart Grid vision. This paper tackles the challenge of Smart Grids and gives a clear representation of the role that heat pump technology can play through its applications in the Smart Grids context. A broad description of the evolution process taking place in the current energy sector is the starting point to outline the new role of heat pumps in this paper. This description is followed by an introduction of the vision of the highly integrated and distributed energy system fostered by Smart Grids, showing how the potential of so called "prosumers" can be unlocked. A conceptual model of the system is developed to highlight the role of major stakeholders and their interactions and also to identify the key role of heat pumps in the future energy system. In addition to this, an assessment of the potential impact of heat pump technology in the Smart Grid context has been evaluated considering the economic savings that could be achieved by a demand response strategy.

  • 122948. Zamulko, S.
    et al.
    Chen, Rongzhen
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap. University of Oslo, Norway.
    Persson, Clas
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap. University of Oslo, Norway.
    Investigation of the structural, optical and electronic properties of Cu2Zn(Sn,Si/Ge)(S/Se)4 alloys for solar cell applications2017Ingår i: Physica status solidi. B, Basic research, ISSN 0370-1972, E-ISSN 1521-3951, Vol. 254, nr 6, artikel-id e201700084Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The crystalline structural, electronic and optical properties of the alloys Cu2ZnSn1−xGexS4, Cu2ZnSn1−xSixS4, Cu2ZnSn1−xGexSe4 and Cu2ZnSn1−xSixSe4 are calculated by first-principles using both the generalized gradient approximation and a hybrid functional approach. We find that the electronic band structures are qualitatively very similar for these alloys. The band-gap energy Eg(x) (for x = 0, 0.125, 0.25, 0.5, 0.75, 0.875 and 1) increases almost linearly with Ge and Si substitution. However, for very Si rich Cu2ZnSn1−xSixS4 alloys (but not for Cu2ZnSn1−xSixSe4) there is an abrupt increase of Eg(x) for x &gt; 0.96. We therefore analyse this effect by calculating the electronic structures for x = 0.93, 0.96 and 1. We find that the Sn-like states form localised density-of-states below the conduction band edge in Cu2ZnSn1−xSixS4, while corresponding states resonate more with the conduction bands in Cu2ZnSn1−xSixSe4. The effect in S-based alloys is a direct consequence of the energetically high conduction band edge for Cu2ZnSiS4 in combination with energetically low Sn-like states. Furthermore, the calculated dielectric constants are relatively similar for all alloy configurations. Overall however, our results suggest that it is possible to use Si and Ge as alloying element in quaternary Cu2ZnSnS4 to improve the photovoltaic properties.

  • 122949.
    Zamulko, Sergiy
    et al.
    Univ Oslo, Ctr Mat Sci & Nanotechnol, POB 1048 Blindern, NO-0316 Oslo, Norway..
    Berland, Kristian
    Univ Oslo, Ctr Mat Sci & Nanotechnol, POB 1048 Blindern, NO-0316 Oslo, Norway..
    Persson, Clas
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap. University of Oslo, P. O. Box 1048 Blindern, Oslo, NO-0316, Norway.
    Optical Properties of Cu2ZnSn(SxSe1-x)(4) by First-Principles Calculations2018Ingår i: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 215, nr 17, artikel-id 1700945Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Structural, electronic, and optical properties of Cu2ZnSn(SxSe1-x)(4) semiconductors are studied theoretically for different concentration of S and Se anions. The optical properties are calculated at three levels of theory, in the generalized gradient approximation (GGA), meta-GGA, and with a hybrid functional. The GGA and meta-GGA calculations are corrected with an on-site Coulomb U-d term. Lattice constants, dielectric constants, and band-gaps are found to vary almost linearly with the concentration of S. The authors also show that a dense sampling of the Brillouin zone is required to accurately account for the shape of the dielectric function, which is hard to attain with hybrid functionals. This issue is resolved with a recently developed kp based interpolation scheme, which allows us to compare results of the hybrid functional calculations on an equal footing with the GGA and meta-GGA results. We find that the hybrid functionals provide the overall best agreement with the experimental dielectric function.

  • 122950. Zamzam, D. M.
    et al.
    Abd El Ghany, M. A.
    Hofmann, K.
    Ismail, Muhammad
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Highly reliable and power efficient NOC interconnects2011Ingår i: NORCHIP, 2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    Network on chip (NOC) architecture interconnects consume significant amount of power, have a large propagation delay and are susceptible to error due to deep sub-micron (DSM) noise. Major challenge that NOC design expected to face is related to intrinsic reliability. By incorporating error control coding schemes along the NOC interconnects, NOC architectures are able to provide correct functionality in the presence of different transient noise source. In this paper we present a novel coding scheme that increase the reliability of the NOC where the area is reduced by 19% and the consumed power by NOC interconnects is decreased by 51%. Butterfly fat tree architecture consumes the minimum power as compared to other NOC architectures.

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