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  • 1.
    Abed, Salwan Ali
    et al.
    Department of Environment, College of Science, University of Al-Qadisiyah, Iraq.
    Ewaid, Salam Hussein
    Technical Institute of Shatra, Southern Technical University, Iraq.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Evaluation of Water quality in the Tigris River within Baghdad, Iraq using Multivariate Statistical Techniques2019Ingår i: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 1294, artikel-id 072025Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This research concentrated on the Tigris River water quality monitoring information. Some multivariate statistical techniques were applied like basic Ingredient (PC) test, discriminant analysis (DA), multiple linear regression analysis (MLRA) to evaluate important parameters affecting water quality during year 2017-2018. The study included 25 water quality parameters, viz., Temperature (T), Potential of Hydrogen (pH), Turbidity (Tur), Total Alkaline (TA), Full rigidity (TH), Calcium (Ca+2), Chloride (Cl-1), Magnesium (Mg+2), Electrical Conductivity (EC), Sulfate (SO4-2), Total Solids (TS), Suspended Solids (SS), Iron (Fe+2), Fluoride (F-1), Aluminum (Al+3), Nitrite (NO2-1), Nitrate (NO3-1), Silica (SiO2), Phosphate (PO4-3), Ammonia (NH3), Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD5), Chemical Oxygen Demand (COD), Sodium (Na+1), and Total Dissolved Solids (TDS). Generally, all the parameters were within the standards except Tur, TA, Ca+2, EC, SO4-2. The levels of Tur and EC are of critical factors influence upon the Tigris water quality. The PCA identified six principal components responsible for 78.12% of the variation caused by the industrial, domestic, municipal and agricultural runoff pollution sources. DA results produced the eight parameters; T, BOD5, EC, Mg+2, DO, Tur, Na+1, and COD as the most significant parameters differentiating the two parts of the year (the cold and warm seasons). The result of MLRA showed that BOD5, Na+1, T, DO, and PO4-3 are the important dependable factors for predicting the COD value as an indicator of organic and nonorganic pollution. This research demonstrated success importance utilizing Multivariate statistical methods like valuable instrument of administration, control, and preserve the water of the river.

  • 2.
    Albertsson, Kim
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Gleyzer, Sergei
    University of Florida.
    Zapata, Omar
    OProject and University of Antioquia.
    Machine Learning in High Energy Physics Community White Paper2018Ingår i: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 1085, artikel-id 022008Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Machine learning is an important applied research area in particle physics, beginning with applications to high-level physics analysis in the 1990s and 2000s, followed by an explosion of applications in particle and event identification and reconstruction in the 2010s. In this document we discuss promising future research and development areas in machine learning in particle physics with a roadmap for their implementation, software and hardware resource requirements, collaborative initiatives with the data science community, academia and industry, and training the particle physics community in data science. The main objective of the document is to connect and motivate these areas of research and development with the physics drivers of the High-Luminosity Large Hadron Collider and future neutrino experiments and identify the resource needs for their implementation. Additionally we identify areas where collaboration with external communities will be of great benefit.

  • 3.
    Bergan, Carl
    et al.
    Department of Energy and Process Engineering, Water Power Laboratory, Norwegian University of Science and Technology, Trondheim.
    Amiri, Kaveh
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik. Department of Engineering Sciences and Mathematics, Luleå University of Technology.
    Cervantes, Michel J.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik. Department of Energy and Process Engineering, Water Power Laboratory, Norwegian University of Science and Technology, Trondheim.
    Dahlhaug, Ole G.
    Department of Energy and Process Engineering, Water Power Laboratory, Norwegian University of Science and Technology, Trondheim.
    Preliminary measurements of the radial velocity in the Francis-99 draft tube cone2015Ingår i: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 579, nr 1, artikel-id 12014Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Two-dimensional particle image velocimetry (PIV) measurements in the draft tube cone of the Francis-99 model have been performed to complete the actual experimental data set with radial velocity data. The velocity profiles obtained presented some variation, which reason has not yet been identified. The presented results are therefore presented as preliminary until the reason is assessed. The axial velocity profiles corroborate well with the ones previously measured with laser Doppler velocimetry (LDV) for all operating points investigated. The radial velocity measured is small in magnitude for all operating points compared to the axial velocity. A gyroscopic effect induced by the swirl leaving the runner and the draft tube bend seems to induce an asymmetry in the draft tube cone.

  • 4.
    Cervantes, Michel
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Trivedi, Chirag
    Norwegian University of Science and Technology (NTNU), Trondheim.
    Dahlhaug, Ole Gunnar
    Department of Energy and Process Engineering, Water Power Laboratory, Norwegian University of Science and Technology, Trondheim, Norwegian University of Science and Technology (NTNU), Trondheim.
    Nielsen, Torbjørn Kristian
    Norwegian University of Science and Technology (NTNU), Trondheim.
    Francis-99 Workshop 1: steady operation of Francis turbines2015Ingår i: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 579, artikel-id 11001Artikel i tidskrift (Övrigt vetenskapligt)
  • 5.
    Cervantes, Michel
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Trivedi, Chirag
    Norwegian University of Science and Technology (NTNU), Trondheim.
    Dahlhaug, Ole Gunnar
    Department of Energy and Process Engineering, Water Power Laboratory, Norwegian University of Science and Technology, Trondheim, Norwegian University of Science and Technology (NTNU), Trondheim.
    Nielsen, Torbjørn Kristian
    Norwegian University of Science and Technology (NTNU), Trondheim.
    Francis-99 Workshop 2: transient operation of Francis turbines2017Ingår i: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 782, artikel-id 11001Artikel i tidskrift (Övrigt vetenskapligt)
  • 6.
    Concina, Isabella
    et al.
    CNR IDASC SENSOR Lab.
    Natile, M.
    Department of Chemical Sciences and INSTM Padova, Padova University.
    Braga, A.
    CNR IDASC SENSOR Lab.
    Vomiero, Alberto
    Department of Physics and Chemistry for Materials and Engineering and CNR-IDASC SENSOR Lab, Brescia University.
    Morandi, V.
    CNR-IMM Sezione di Bologna.
    Ortolani, L.
    CNR-IMM Sezione di Bologna.
    Ferroni, M.
    CNR IDASC SENSOR Lab.
    Sberveglieri, G.
    CNR IDASC SENSOR Lab.
    One pot synthesis of bi-linker stabilised CdSe quantum dots2010Ingår i: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 244, artikel-id 12067Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study we exploited the classic Murray's synthesis for generating a hydrophilic CdSe quantum dot system in a single step procedure, with the aim of directly obtaining a material responding to the characteristic of polarity required in many end applications. 6-phosphonohexanoic acid was used as both ligand for generating the active monomer during the synthesis of the quantum dots and final stabiliser. Diffraction measurements identified the cubic phase of cadmium selenide. Energy dispersive spectroscopy analysis revealed non-stoichiometric quantum dots, being the Cd/Se ratio 60/40. This feature suggests a configuration in which Cd2+ ions are present on the nanocrystal surface. Diffuse reflectance infrared Fourier transform analysis was applied in order to investigate the structure of the quantum dot system: the results indicate a configuration in which the carboxylic function of 6-phosphonohexanoic acid establishes only a partial interaction with the quantum dot surface, being set in a pseudo-ester configuration. © 2010 IOP Publishing Ltd.

  • 7.
    Fakhardji, Wissam
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Gustafsson, Magnus
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Molecular dynamics simulations of collision-induced absorption: Implementation in LAMMPS2017Ingår i: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 810, nr 1, artikel-id 012031Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We pursue simulations of collision-induced absorption in a mixture of argon and xenon gas at room temperature by means of classical molecular dynamics. The established theoretical approach (Hartmann et al. 2011 J. Chem. Phys. 134 094316) is implemented with the molecular dynamics package LAMMPS. The bound state features in the absorption spectrum are well reproduced with the molecular dynamics simulation in comparison with a laboratory measurement. The magnitude of the computed absorption, however, is underestimated in a large part of the spectrum. We suggest some aspects of the simulation that could be improved

  • 8.
    Frómeta, D.
    et al.
    Fundació CTM Centre Tecnològic, Plaça de la Ciència 2, Manresa, Spain.
    Tedesco, M.
    Centro Ricerche Fiat, Corso Settembrini 40, Turin, Italy.
    Calvo, J.
    Universitat Politècnica de Catalunya, Eduard Maristany 10-14, Barcelona, Spain.
    Lara, A.
    Fundació CTM Centre Tecnològic, Plaça de la Ciència 2, Manresa, Spain.
    Molas, S.
    Fundació CTM Centre Tecnològic, Plaça de la Ciència 2, Manresa, Spain.
    Casellas, Daniel
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik. Fundació CTM Centre Tecnològic, Plaça de la Ciència 2, Manresa, Spain.
    Assessing edge cracking resistance in AHSS automotive parts by the Essential Work of Fracture methodology2017Ingår i: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 896, artikel-id 012102Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Lightweight designs and demanding safety requirements in automotive industry areincreasingly promoting the use of Advanced High Strength Steel (AHSS) sheets. Such steelspresent higher strength (above 800 MPa) but lower ductility than conventional steels. Their greatproperties allow the reduction of the thickness of automobile structural components withoutcompromising the safety, but also introduce new challenges to parts manufacturers. Thefabrication of most cold formed components starts from shear cut blanks and, due to the lowerductility of AHSS, edge cracking problems can appear during forming operations, forcing thestop of the production and slowing down the industrial process.Forming Limit Diagrams (FLD) and FEM simulations are very useful tools to predict fractureproblems in zones with high localized strain, but they are not able to predict edge cracking. Ithas been observed that the fracture toughness, measured through the Essential Work of Fracture(EWF) methodology, is a good indicator of the stretch flangeability in AHSS and can help toforesee this type of fractures.In this work, a serial production automotive component has been studied. The componentshowed cracks in some flanged edges when using a dual phase steel. It is shown that theconventional approach to explain formability, based on tensile tests and FLD, fails in theprediction of edge cracking. A new approach, based on fracture mechanics, help to solve theproblem by selecting steel grades with higher fracture toughness, measured by means of EWF.Results confirmed that fracture toughness, in terms of EWF, can be readily used as a materialparameter to rationalize cracking related problems and select AHSS with improved edgecracking resistance.

  • 9.
    Golling, Stefan
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Östlund, Rickard
    Gestamp HardTech.
    Oldenburg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Modeling of multi-phase microstructures in press hardened components plastic deformation and fracture in different stress states2017Ingår i: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, artikel-id 012053Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Hot stamping or press hardening is an industrialized technique with the aim of improving material properties by heat treatment and forming of a component in a single production stage. Within the field of press hardening the method of tailored material properties evolved. Components with tailored material properties possess different mechanical properties in designated areas. This paper presents an approach for modeling the mechanical response of mixed microstructures under different stress states. A homogenization method is used to predict the hardening of the material; the strain decomposition provides the possibility of applying a fracture criterion per phase. To validate the modeling approach for different stress states a set of samples with different notch and hole geometries as well as microstructural composition are produced. The combination of a homogenization method and a fracture criterion show good agreement with experimental results. The homogenization method is suitable to predict the hardening of the material with good accuracy. Fracture for different microstructural compositions is well predicted over a range of stress triaxialities relevant for sheet metal applications. It is concluded that the use of a homogenization method combined with a fracture model can be used to predict the mechanical response of mixed microstructures for a range of different stress states.

  • 10.
    Goyal, Rahul
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik. Indian Institute of Technology Roorkee.
    Gandhi, Bhupendra K.
    Indian Institute of Technology Roorkee.
    Cervantes, Michel
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Transient Pressure Measurements in the Vaneless Space of a Francis Turbine during Load Acceptances from Minimum Load2018Ingår i: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 1042, artikel-id 012009Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Increased penetration of solar and the wind impels the designers of the hydroelectric power generation unit to provide more flexibility in operation for the stability of the grid. The power generating unit includes turbine which needs to sustain sudden change in its operating conditions. Thus, the hydraulic turbine experiences more transients per day which result in chronic problems such as fatigue to the runner, instrument malfunctioning, vibrations, wear and tear etc. This paper describes experiments performed on a high model (1.5:1) Francis turbine for load acceptances from the minimum load. The experiments presented in the paper are the part of Francis-99 workshop which aims to determine the performance of numerical models in simulations of model Francis turbine under steady and transient operating conditions. The aim of the paper is to present the transient pressure variation in the vaneless space of a Francis turbine where high-frequency pulsations are normally expected. For this, two pressure sensors, VL1 and VL2, are mounted at the vaneless space, one near the beginning of the spiral casing and the other before the end of the spiral casing. Both are used to capture the unsteady pressure field developed in the space between guide vanes and runner inlet. The time-resolved pressure signals are analyzed and presented during the transient to observe the pressure variation and dominant frequencies of pulsations.

  • 11.
    Gustafsson, Magnus
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Hydrogen dimer features in low temperature collision-induced spectra2017Ingår i: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 810, nr 1, artikel-id 012017Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The absorption of radiation in pure hydrogen (H2) gas around the S(0) and S(1) rotational transitions is computed at 20 K and compared with laboratory data. All transitions involving free state are included in the calculations of the absolute absorption. These calculations are done with an isotropic approximation for the H2–H2 pair potential. Agreement with the experiment is observed around the S(0) transition, while the computational approach appears to be slightly worse around the S(1) transition. The positions for bound-to-bound transitions are computed including the full anisotropic pair potential. The anisotropy seems to be crucial to achieve agreement with the measured bound-to-bound transition frequencies. However, those transitions contribute little to the total absorption. The present computed absolute absorptions will provide improved input for radiative transfer models of planetary atmospheres.

  • 12.
    Gustafsson, Magnus
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Gļaz, Waldemar
    Nonlinear Optics Division, Faculty of Physics, Adam Mickiewicz University.
    Bancewicz, Tadeusz
    Nonlinear Optics Division, Faculty of Physics, Adam Mickiewicz University.
    Godet, Jean Luc
    Laboratoire de Photonique D'Angers, Université D'Angers.
    Maroulis, George
    Department of Chemistry, University of Patras.
    Haskopoulos, Anastasios
    Department of Chemistry, University of Patras.
    Calculated isotropic Raman spectra from interacting H2-rare-gas pairs2014Ingår i: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 548, artikel-id 12027Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report on a theoretical study of the H2-He and H2-Ar pair trace-polarizability and the corresponding isotropic Raman spectra. The conventional quantum mechanical approach for calculations of interaction-induced spectra, which is based on an isotropic interaction potential, is employed. This is compared with a close-coupling approach, which allows for inclusion of the full, anisotropic potential. It is established that the anisotropy of the potential plays a minor role for these spectra. The computed isotropic collision-induced Raman intensity, which is due to dissimilar pairs in H2-He and H2-Ar gas mixtures, is comparable to the intensities due to similar pairs (H2-H2, He-He, and Ar-Ar), which have been studied previously.

  • 13.
    Gustafsson, Magnus
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Nyman, Gunnar
    Department of Chemistry and Molecular Biology, University of Gothenburg.
    The emission spectrum due to molecule formation through radiative association2014Ingår i: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 548, artikel-id 12003Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Quantum mechanical and classical methods for theoretical analysis of the emission spectrum due to radiative association are presented. Quantum mechanical perturbation theory is employed to obtain the spectra when the diatomic molecule HF forms by transitions within the electronic ground state and when it forms by transitions between two electronic states. We contrast these spectra with each other. The former peaks in the infrared, while the latter peaks in the ultraviolet. The classical spectrum, which concerns transitions within the electronic ground state, is also calculated and found to favorably compare with that from quantum mechanical perturbation theory. The emission stemming from resonance mediated radiative association is also discussed.

  • 14.
    Lichtenegger, Klaus
    et al.
    Bioenergy 2020+ GmbH.
    Hebenstreit, Babette
    Bioenergy 2020+ GmbH.
    Pointner, Christian
    Bioenergy 2020+ GmbH.
    Leak air in a double-wall chimney system2013Ingår i: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 410, s. 1-4Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Operating biomass stoves in modern buildings with tight shells often requires a room-independent air supply. One possibility to arrange this supply is to use a double-wall chimney with fresh air entering through the annular gap. For this setup, a mathematical model has been developed and checked with experimental data. It turned out that for commercially available chimneys, leakage is not negligible and inclusion of leak air in the calculation is crucial for reproduction of the experimental data. Even with inclusion of this effect, discrepancies remain which call for further investigations and a refinement of the model.

  • 15.
    Lichtenegger, Klaus
    et al.
    Bioenergy 2020+ GmbH.
    Schappacher, Wilhelm
    Institute of Mathematics and Scientific Computing, Karl-Franzens-Universität.
    Hebenstreit, Babette
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Schmidl, Christoph
    Bioenergy 2020+ GmbH.
    Höftberger, Ernst
    Bioenergy 2020+ GmbH.
    Towards a Stochastic Cellular Automata Model of Log Wood Combustion2014Ingår i: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 490, nr 1, artikel-id 12015Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Describing the combustion of log wood and others solid fuels with complex geometry, considerable water content and often heterogenous struture is a nontrivial task. Stochastic Cellular Automata models offer a promising approach for modelling such processes. Combustion models of this type exhibit several similarities to the well-known forest fire models, but there are also significant differences between those two types of models. These differences call for a detailed analysis and the development of supplementary modeling approaches. In this article we define a qualitative two-dimensional model of burning log wood, discuss the most important differences to classical forest fire models and present some preliminary results. © Published under licence by IOP Publishing Ltd.

  • 16.
    López-Delgado, R.
    et al.
    MEMS Research Lab, Department of Physics and Astronomy, University of Texas at San Antonio.
    Zhou, Yufeng
    INRS-EMT, Varennes, QC.
    Zazueta-Raynaud, A.
    MEMS Research Lab, Department of Physics and Astronomy, University of Texas at San Antonio.
    Zhao, Haiguang
    INRS-EMT, Varennes, QC.
    Vomiero, Alberto
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Pelayo, J.E.
    MEMS Research Lab, Department of Physics and Astronomy, University of Texas at San Antonio.
    Álvarez-Ramos, Mario Enrique
    Departamento de Física, Universidad de Sonora, Son, Hermosillo.
    Rosei, Frederico
    Centre for Energy, Materials and Telecommunications, Institut National de la Recherche Scientifique, Université du Québec, Varennes, Québec.
    Ayon, Arturo Arturo
    MEMS Research Lab, Department of Physics and Astronomy, University of Texas at San Antonio.
    Influence of photo-luminescent CdSe/CdS core shell quantum dots in solar cell efficiency2016Ingår i: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 773, nr 1, artikel-id 012088Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report the synthesis and characterization of CdSe/CdS core-shell quantum dots (CdSe/CdS-QDs) that exhibit absorption in the UV range of the solar spectrum and emit photons with wavelengths centered around 625 nm, a wavelength that is well suited for silicon absorption and electron-hole pair generation. We also report the fabrication and characterization of single crystal silicon (c-Si) solar cells with and without the aforementioned photo luminescent, down-shifting CdSe/CdS- QDs. The incorporation of these nanostructures triggered improvements in the performance of the devices, particularly in the open circuit voltage (Voc) and short circuit current density (Jsc) for which the measured values showed an increase from 543 to 546 mV and from 32.5 to 37.0 mA/cm2, respectively. The combined effect of the improved values led to an increment in the power conversion efficiency (PCE) from 12.01 to 13.54%. This increase represents a 12.7% improvement in the PCE of the fabricated devices. The effort described herein is considered a good fit to the generalized trend to improve the efficiency of solar cells with mass-compatible techniques that could serve to promote their widespread utilization

  • 17.
    Maggioni, Gianluigi
    et al.
    INFN - Legnaro National Laboratories.
    Carturan, Sara
    INFN - Legnaro National Laboratories.
    Quaranta, Alberto
    INFN - Legnaro National Laboratories.
    Vomiero, Alberto
    INFN - Legnaro National Laboratories.
    Tonezzer, Michele
    INFN - Legnaro National Laboratories.
    Mea, Gianantonio Della
    INFN - Legnaro National Laboratories.
    Production and characterization of thin film materials for indoor optical gas sensing applications2006Ingår i: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 41, nr 1, s. 531-534, artikel-id 62Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Pure and Nile-Red-doped polyimide and porphyrin films have been deposited and their optical response to different organic vapours has been tested. Polyimide films were obtained by spin coating a solution containing 4, 4'-4, 4'-(hexafluoroisopropylidene) diphthalic anhydride and 2, 3, 5, 6-tetramethyl-1, 4-phenylenediamine. Free, cobalt and iron chloride 5, 10, 15, 20 meso-tetraphenyl porphyrin films were deposited by spin coating and by high vacuum evaporation. Exposure to water, ethanol and isopropanol vapours produce reversible changes of the fluorescence features of both pure and doped polyimide films. Exposure to methanol, ethanol and isopropanol vapours gives rise to changes of the optical absorption of porphyrin films. The results of the optical measurements point out that the synthesized films can be used for the detection of volatile organic compounds. © 2006 IOP Publishing Ltd.

  • 18.
    Pujante, J.
    et al.
    Fundaci´o CTM Centre Tecnol`ogic, Pla¸ca de la Ci`encia 2, Spain .
    Garcia-Llamas, E.
    Fundaci´o CTM Centre Tecnol`ogic, Pla¸ca de la Ci`encia 2, Spain .
    Golling, Stefan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik. Fundaci´o CTM Centre Tecnol`ogic, Pla¸ca de la Ci`encia 2, Spain .
    Casellas, Daniel
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik. Fundaci´o CTM Centre Tecnol`ogic, Pla¸ca de la Ci`encia 2, Spain .
    Microstructural and mechanical study of press hardening of thick boron steel sheet2017Ingår i: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 896, artikel-id 012085Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Press hardening has become a staple in the production of automotive safetycomponents, due to the combination of high mechanical properties and form complexity itoffers. However, the use of press hardened components has not spread to the truck industrydespite the advantages it confers, namely affordable weight reduction without the use of exoticmaterials, would be extremely attractive for this sector.The main reason for this is that application of press hardened components in trucks impliesadapting the process to the manufacture of thick sheet metal. This introduces an additionallayer of complexity, mainly due to the thermal gradients inside the material resulting inthough-thickness differences in austenitization and cooling, potentially resulting in complexmicrostructure and gradient of mechanical properties.This work presents a preliminary study on the press hardening of thick boron steel sheet.First of all, the evolution of the sheet metal during austenitization is studied by means ofdilatometry tests and by analysing the effect of furnace dwell time on grain size. Afterwards,material cooled using different cooling strategies, and therefore different effective cooling rates, isstudied in terms of microstructure and mechanical properties. Initial results from finite elementsimulation are compared to experimental results, focusing on the phase composition in throughthickness direction.Results show that industrial-equivalent cooling conditions do not lead to gradientmicrostructures, even in extreme scenarios involving asymmetrical cooling.

  • 19.
    Quaranta, A.
    et al.
    Universit di Trento.
    Dran, J. C.
    Centre de Recherche et de Restauration des Musées de France.
    Salomon, J.
    Centre de Recherche et de Restauration des Musées de France.
    Pivin, J. C.
    CSNSM-IN2P3, Bâtiment 108, 91405 Orsay.
    Vomiero, Alberto
    Laboratori Nazionali di Legnaro.
    Tonezzer, M.
    Universit di Trento.
    Maggioni, G.
    Universit di Trento.
    Carturan, S.
    INFN.
    Mea, G. Della
    Universit di Trento.
    Analysis of art objects by means of ion beam induced luminescence2006Ingår i: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 41, nr 1, s. 543-546, artikel-id 65Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The impact of energetic ions on solid samples gives rise to the emission of visible light owing to the electronic excitation of intrinsic defects or extrinsic impurities. The intensity and position of the emission features provide information on the nature of the luminescence centers and on their chemical environments. This makes ion beam induced luminescence (IBIL) a useful complement to other ion beam analyses, like PIXE, in the cultural heritage field in characterizing the composition and the provenience of art objects. In the present paper, IBIL measurements have been performed on inorganic pigments for underlying the complementary role played by IBIL in the analysis of artistic works. Some blue and red pigment has been presented as case study. © 2006 IOP Publishing Ltd.

  • 20.
    Tabatabaei, Narges
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Cervantes, Michel
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Trivedi, Chirag
    Norwegian University of Science and Technology.
    Aidanpää, Jan-Olov
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Numerical Study of Aerodynamic Characteristics of a Symmetric NACA Section with Simulated Ice Shapes2016Ingår i: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 753 A, artikel-id 022055Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    To develop a numerical model of icing on wind turbine blades, a CFD simulation was conducted to investigate the effect of critical ice accretions on the aerodynamic characteristics of a 0.610 m chord NACA 0011 airfoil section. Aerodynamic performance coefficients and pressure profile were calculated and compared with the available measurements for a chord Reynolds number of 1.83x106. Ice shapes were simulated with flat plates (spoiler-ice) extending along the span of the wing. Lift, drag, and pressure coefficients were calculated in zero angle of attack through the steady state and transient simulations. Different approaches of numerical studies have been applied to investigate the icing conditions on the blades. The simulated separated flow over the sharp spoilers is challenging and can be seen as a worst test case for validation. It allows determining a reliable strategy to simulate real ice shapes [1] for which the detailed validation cannot easily be provided.

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