1Department of Mechanical System Engineering, Pukyong National University, South Korea
2Department of Information and Communications Engineering, Pukyong National University, South Korea
The efficiencies of thermal power system using fossil fuel depend on heat exchangers which extract energy from the exhaust gas before it is expelled to the atmosphere. To increase heat transfer efficiency it is very important to maintain the surface of heat exchanger as clean condition. The accepted skill of cleaning of fouled surface of heat exchanger is soot blowing. A high pressure jet of air is forced through the flat surface of plate to remove the deposit of fouling. There is, however, little knowledge of the fundamental principles of how the jet behave on the surface and how the jet actually removes the deposit. Therefore, the study focuses on the measuring of cleaning area and cleaning dwell time after accumulating the simulated deposit on the flat surface. The deposit test rig was built for the study and simulated deposit material is used after measuring the physical property of the each material by shearing stress test. Much data was obtained for the analysis by the parameters change such as the different jet speed, different inner pressure and variable distance of the jet from the test rig surface. The experimental data was compared with the theoretical equation and most of the data matches well except some extreme cases.
Biography:
Dr. Kyuil Han received his B.S. Degree in Mechanical Engineering in 1977 from Seoul National University. He received his M.S. Degree in Mechanical Engineering in 1984 from Ohio State University and received a Ph.D. Degree in Mechanical Engineering in 1989 from Colorado State University. Present Kyuil Han is a Professor of Mechanical System Engineering in Pukyong National University in Busan, KOREA. His research Interest field is an efficiency increment of energy transfer for heat exchanging device and thermal power engineering.
1Department of Metallurgical Engineering, Pukyong National University, Republic of Korea
2Extractive Metallurgy Department, Korea Institute of Geoscience & Mineral Resources, Republic of Korea
A Recovery of copper from wasted sludge containing copper has been conducted through various processes. The sludge was analyzed by XRD (X-ray diffraction) and it was found to be amorphous phase. The specimen was oxidized in air for 24 hours to transform crystalline phases that are CuO, Cu(SO)4, Ca(SO)4, Fe3O4 and Fe2(H2O4((SO4)2O)(H2O)4. The specimen was placed into alumina crucible and it was placed in reactor. Reduction reaction was conducted by introducing hydrogen gas at 500°C for 2 hours. When reduction was done, the sample was examined by XRD and it was found to be Cu, Fe, Cu(SO)4, Fe2O3, Cu2FeS4. In the long run, copper content in the sludge was increased from 54.30 wt.% to 70.68 wt.%.
Biography:
Based on his knowledge and experience he is now working at Department of Metallurgical Engineering in Pukyong National University as an Associate Professor. He worked at LS-Nikko Copper Smelting company for one year as a researcher and did various projects including copper smelting, recovery of nickel from smelting dust, and refining of tellurium and selenium etc. Now he is also doing many projects related with fabrication of nanosized metallic powder, recycling process, composite material, corrosion engineering, powder metallurgy, and extractive process.
Department of Applied Science and Technology, Politecnico di Torino, Corso Ducadegli, Italy
Bars of Ti-48Al-2Cr-2Nb, Ti-48Al-2Nb-0.7Cr-0.3Si, Ti-43.5Al-4Nb-1Mo and Ti-47Al-2Cr-8Nb alloys were produced by Electron Beam Melting. The oxidation resistance in air of these alloys was investigated in the range of 800-1000 °C. Oxidation tests were performed in TGA equipment under isothermal conditions at different temperatures. The composition of the oxide layers was investigated by XRD, SEM-EDS and XPS. The oxide layers grew according to a parabolic law. The kinetic rate constants and the activation energies were calculated from the TGA results. These kinetic parameters allowed to asses a rank of oxidation resistance, which can be correlated with the composition of the alloys.
Biography:
Oxana Ostrovskaya graduated in chemical technology of refractory non-metal and silicate materials at Belgorod Shukhov State Technological University (Russian Federation) in 2003, and she received her M.S. Degree in Materials Science and Technology from Politecnico di Torino (Italy) in 2014. At present, she is a Ph.D student in Materials Science and Technology at “Politecnico di Torino”, Italy. Currently, her researches focus on Intermetallic Alloys with or within thin protective coating for aerospace applications. Oxana Ostrovskaya co-authored 3 paper articles.
1Instituteof Condensed Matter Physics, Linyi University, China
2School of Physics, Shandong University, China
3School of Physics and Electric Engineering, Anyang Normal University, China
The adsorption and gas-sensing characteristics of CO2 and CO molecules on stoichiometric α-Fe2O3 (0 0 1) nano-thin film with and without pre-adsorbed O2 molecules had beenstudied using the density functional theory (DFT) method. Without preadsorbed O2 molecules, CO2 molecule played as an acceptor and obtains electrons from stoichiometric α-Fe2O3 (0 0 1) nano-thin film. For the O2 pre-adsorption α-Fe2O3 (0 0 1) nano-thin film system, the CO2 molecule alsoplayedas an acceptor. However, less number of electrons was transferred to CO2 molecule ascompared to pre-adsorbed O2 molecule. Different from CO2 molecule, CO molecule always played as a donor for α-Fe2O3 (0 0 1) nano-thin film system with and without pre-adsorbed O2. The theoretical results verify that the CO molecule can react with lattice or adsorbed oxygen of α-Fe2O3 (0 0 1) nano-thin film. The electrons transferred to the stoichiometric α-Fe2O3 (0 0 1) nano-thin film from CO molecule/new formed CO2 molecule were more than that of transferred to the O2 pre-adsorption α-Fe2O3 (0 0 1) nano-thin film. For stoichiometric or O2 pre-adsorption α-Fe2O3 (0 0 1) nano-thin film, the CO2 and CO moleculesexhibited opposite behaviors ofcharge transformation. In addition, pre-adsorbed O2 molecules displayed competitive adsorption with CO2 or CO molecule. The pre-adsorbed O2 molecules hinder electron transfer to CO2 molecule from α-Fe2O3 (0 0 1) nano-thin film or hinder electron transfer to α-Fe2O3 (0 0 1) nano-thin film from CO molecule. Theoretical results demonstrate that the (0 0 1) surface of α-Fe2O3 materials could be prepared as adsorbents or gas sensors for CO2 and CO molecules. Their structures were stable after CO2 molecules were adsorbed or after the reaction of CO molecules withlattice or adsorbed oxygen of α-Fe2O3 (0 0 1) nano-thin film.
Biography:
Changmin Shi was born in May 26, 1986. He received his B.S. degree in Condensed Matter Physics (2010-2015) from Shandong University. At present, he worked as a teacher in Institute of Condensed Matter Physics, School of Physics and Electric Engineering, Linyi University.
Institute of Condensed Matter Physics, Linyi University, School of Physics, Shandong University, China
Based on first-principles calculations, we propose one new category of two-dimensional topological insulators (2D TIs) in chemically functionalized (-CH3, -OH and halogens) arsenene films. The results show that the surface decorated arsenene films are intrinsic 2D TIs, which are verified by calculating the edge states with obvious linear cross inside bulk energy gap. The bulk energy gaps range from 0.184 eV for AsCH3 film to 0.304 eV for AsOH films, which make them suitable to realize quantum spin Hall effect in an experimentally accessible temperature regime. These novel 2D TIs are potential candidate in future electronic devices with ultralow dissipation.
Biography:
Dongchao Wang gained his Ph.D from School of Physics, Shandong University. He joined the institute of condensed matter physics, school of physics and electric engineering, Linyi University in July 2016. His major is in the area of condensed matter theory, nanostructures and quantum devices. His research project is on theoretical and computational studies of structural and electronic properties of two-dimensional materials.
1Institute of Condensed Matter Physics, Linyi University, China
2Physics Department, Lancaster University, UK
Using first-principle calculations, we report for the first time, the changes in electronic structures of a single bilayer Sn stacked on a single bilayer Sb (Bi) and on a single quintuple layer Sb2Te3 induced by both interface polarization and strain. With BL, Bi, and QL Sb2Te3 substrates, the stanene tends to have a low-buckled configuration, whereas with BL Sb substrate, the stanene prefers to form high-buckled configurations. For strained Sn/Sb(Bi) system, we find that the Dirac cone state is not present in the band gap, whereas in strained Sn/Sb2Te3 system, spin-polarized Dirac cone can be introduced into the band gap. We discuss why tensile strain can result in the Dirac cone emerging at the K point based on a tight-binding lattice model. This theoretical study implies the feasibility of realizing quantum phase transitions for Sn thin films on suitable substrates. Our findings provide an effective manner in manipulating electronic structures and topological states in interfacial systems by using interface polarization and strain, which opens a new route for realizing atomically thin spintronic devices.
Biography:
Li Chen gained her Ph.D from School of Physics, Shandong University. She worked in Institute of Condensed Matter Physics, School of Physics and Electric Engineering, Linyi University. Her major is in the area of condensed matter theory, quantum Hall effect, nanostructures and quantum devices. Her research project is on theoretical and computational studies of structural and electronic properties of electronic materials.
King Abdullah University of Science & Technology (KAUST), Saudi Arabi
Semiconductor quantum-dot (QD) lasers are well known of exhibiting superior performance due to the delta-like function of the discrete density-of-states, resulting in low-threshold current densities, and high gain. Arising from the size, composition and strain distribution in and around the QD, multi-state lasing are resulting, and leading to emission broadening. For monolithic integration of photonic integrated circuits, the selective area intermixing technique is preferred.
Controlling the Lasing spectra of QD lasers is highly desirable for certain application. The wide spectral bandwidth of the light source determines the coherence length which in turn determines the resolution of imaging optical coherence tomography (OCT) systems, Broad band light source are vital component for wavelength division multiplexing (WDM), and. Various methods have been proposed and utilized to achieve broad spectral bandwidth light emission from QD devices, such as using multilayer stacks of QDs with different emission wavelength for each layer, hybrid quantum well (QW)/quantum dot structures, optimizing the growth conditions to increase the inhomogeneous dot size distribution, or using multi-contact device structures. Quantum dots intermixing is a promising technique, to modify confining potential throw atoms inter diffusion, by increasing the effect of interface fluctuations between the QDs and their surrounding barrier layer materials shows as change in emission spectra.
In this work, we will present the systematic post-growth thermal annealing studies using various dielectric capping TiO2, SiO2, SrTiO3, HfO2, Si3N4, ZnO, and Al2O3, to control the degree of intermixing for tuning the energy spacing between ground and exited states during the spontaneous emission process, and with the view of achieving the broadest emission. We determined the best capping and annealing process to achieve the broadest emission from each capping, followed by selecting three specific capping layer to gain the highest broadening. Our experimental results show that annealing at 650°C for 120s are the best conditions to achieve the broadest spontaneous emission spectra. The QD laser structure capped with Al2O3, HfO2 and SiO2 gave emission wavelength and full-width at half-maximum (FWHM) of 1200nm / 182nm, 1210 nm / 153 nm, and 1110nm / 116nm, respectively. By combining these three selectively dielectric capping, a broad emission with 200 nm FWHM can be achieved. Otherwise even if only use Al2O3 as one capping a large emission of 182 nm can be achieved.
Biography:
Hala Al-Hashim, is a Ph.D Candidate in Material Science & Engineering since 2011, at King Abdullah University of Science & Technology (KAUST), within the Academic Division of Physical Science & Engineering. Her work is centered around developing and integrating innovative statistical approaches to advance research in Tuning Lasing Wavelength in III/V semiconductor quantum dot/quantum well devices which gives wide range of interested in applications such as biomedical imaging, optical communications. Halaʼs methodological research focuses on the field of solid state physics, photonic materials, nanofabrication, and advance engineered materials. She is a specialist in semiconductor material solid state lightening, has a very extensive knowledge in solid state physics, and analyzing & improving scientific projects. Mrs. Al-Hashim works as an effective instructor with 9 years of experience in developing labs. She was capable of generating enthusiasm in others and inspiring them to be innovative in their field. Hala received her Master Degree in physics from the Dammam University.
1Faculty of Chemical and Process Engineering, Warsaw University of Technology, Poland
2Department of Materials Engineering, Tatung University, Taiwan
3School of Dental Technology, College of Oral Medicine, Taipei Medical University, Taiwan
Materials for infrared shielding can be used in many different applications, such as heat shielding in smart windows. For this purpose many different materials have been studied, such as indium tin oxide (ITO), antimony tin oxide (ATO), tungsten oxide (WO3), lanthanum hexaboride (LaB6). In our investigations we have prepared polymer composites (polyvinyl alcohol matrix) with different amounts of inorganic fillers, i.e. zinc oxide (ZnO) and iron oxide (Fe2O3). We have studied the influence of the amount of the filler and the preparation method on the properties of the obtained composites.
Preparation of the composites involved using either an ultrasonic homogenizer or a planetary ball mill. The obtained composites were characterized with FT-IR spectroscopy (in attenuated total reflectance – ATR and in transmission mode), thermogravimetric analysis (TGA), and optical microscopy. The heat shielding was examined by a thermal insulation experiment.
The results show that both the preparation method and the amount of the filler have great impact on the physicochemical properties of the obtained composite.
Biography:
Dr. Marta Mazurkiewicz-Pawlicka is an assistant professor at the Faculty of Chemical and Process Engineering, Warsaw University of Technology since 2016. She obtained her doctorate from the Faculty of Materials Science and Engineering, Warsaw University of Technology for the thesis focusing on preparation of palladium catalysts on carbon nanotubes used in direct formic acid fuel cell. Her work focuses on carbon nanomaterials, their functionalization and applications in low-temperature fuel cells and polymer composites. She is an author of 28 scientific papers published in international peer-reviewed journals.
Faculty of Chemical and Process Engineering, Warsaw University of Technology, Poland
Inorganic nanocrystals attract great interest due to their unique physical properties and immense potential for applications. In particular, magnetic nanocrystals offer exciting opportunities for technologies on the interfaces between chemistry, physics, biology, and medicine. The aim ofour research was investigation of the influence of preparation conditions on the magnetic properties of iron oxide/graphene composites. Graphene oxide (GO) were prepared via modified Hummerʼs method. Iron oxide nanoparticles deposited on the graphene surface were prepared bysol-gel methodunder different conditions e.g. pH, temperature, time. The obtained composites were characterizedby: i) X-ray diffraction (XRD) – to determine the average size of crystallites and the phase composition, ii) electron microscopy (SEM/STEM) – for imaging the metal oxide distributionon the surface of graphene flakes, iii) thermo-gravimetric analysis (TGA) – for determining the thermal stability and percentage content of graphene and metal oxides. Absorption of IR radiation were measured using FT-IR spectrometer in the range of 400 – 7000 cm-1.
Keywords: graphene oxide, nanocomposites, metal oxide, IR shielding.
Shahıd Rajaeı Unıversıty, Iran
We study the conductance of charge carriers through silicene and graphene based superlattices consisting of monolayer graphene and silicene by means of transfer matrix method. The system consists of a sequence of the silicene based barriers and graphene based wells. We consider the ordered superlattices and caculate the transmission probability of dirac fermions. We show that there is resonance picks in transmission probablity and the number of resonance picks increases with increasing the number of superlattice barriers. Also, the effect of structural parameters on the conductance of the system are studied. We compute numerically the conductance of the system and plot versus the hight of the potential barriers and show that it has the osilatory behavior. This behavior is in contrast to the schrodinger equation that conductance decay with increasing the barrier height.
Bulk Semiconductors Crystal Growth team (CSM). Research Center in Semiconductors Technologies for the Energetics (CRTSE), Algeria
Cu2ZnSnS4 (CZTS) is one of the most promising and emerging quaternary absorber materials for thin film solar cells because of its low-cost, non-toxic constituents, ideal direct band gap and high absorption coefficient. In this work, we studied the effect of zinc excess on the crystallization of Cu2ZnSnS4 compound. For this purpose, we synthesized by solid state reaction three CZTS crystals initially with 0.2, 0.4 and 0.6 wt.% of zinc excesses. The CZTS crystals were analyzed using X-ray fluorescence (XRF) to determine chemical composition, X-ray diffraction (XRD) to examine structural properties and Raman scattering for vibrational properties. The composition ratio of [Cu]/([Zn]+[Sn]) is in the range of 0.81-097 while the [Zn]/[Sn] ratio varies from 0.97 to 1.33. The sample with 0.6 at% zinc excess, thus, can be considered optimal for reaching high efficiencies in CZTS based thin films solar cells. XRD profiles exhibit major peaks at 2θ=28.45°, 47.35° and 56.12° for the three samples. These peaks are attributed respectively to the (112), (220) and (312) kesterite planes (JCPDS N°:04-003-8920). The lattice parameters a and c calculated from XRD analysis were respectively 5.429Å and 10.870Å. However, ZnS and Cu4Sn7S16 secondary phases were found. Furthermore, segregation of Cu2-xS phase occurs, as can be seen in Fig.2. Raman scattering spectrum of the sample with 0.6 wt.% excess zinc depicts a weak band at 471cm-1 corresponding to the Cu2-xS phase. Even so, the kesterite phase was confirmed bythe presence of four strong bands at 247cm-1, 294cm-1, 333cm-1 and 364cm-1.
Biography:
Khelfane Amar was born on 18/03/1979 in Bouira, Algeria. He graduated from magister in 2012, a physical option for materials and components at the USTHB University in Algiers. He worked as a physics teacher in high school for two and a half years before joining the CRTSE Research Center in Algiers in December 2014 where he worked as a researcher inBulk Semiconductors Crystal Growth team (CSM) working in photovoltaic materials of 3rd generation Cu2Zn(Ge)SnS4.
1University Center Belhadj Bouchaïb, Algeria
2Laboratoire Matériaux (LABMAT) Ecole Nationale Polytechnique (ENP) dʼOran, Algeria
The electron distribution in the valence band and on the core levels in the CTO (Conductive Transparent Oxide) In2O3 is very important to predict its applications. We adopt the calculation simulation based on the approximations GGA (Generalized Gradient Approximation) and mBJ (modified Becke Johnson) using the program Wien2K to obtain the electron distribution. The valence band involves the hybridation of states s and p of chemical species indium and oxygen in the range -6eV to 0eV. The features related to these states s and p are very discriminated from other features located to low energies related to states d of indium in the range -13 eV to -11eV. The calculation results enable us to predict the interband transition. Furthermore, the electron distribution around the cation (indium) and anion (oxygen) allows us to determine the ionic character of the chemical bond in the In2O3 compound.
We confirm such results owing to the characterization methods by the electron spectroscopy AES (Auger Electron Spectroscopy) and EELS (Electron Energy Loss spectroscopy).
Keywords: GGA and mBJ approximations; oxides CTO; AES and EELS spectroscopy.
1Institut des Sciences, Centre University dʼAin Temouchent, Algeria
2Laboratory dʼEtude des Matériaux et Instrumentations Optiques, Faculté des Sciences Exactes, University de Sidi Bel-Abbes, Algeria
We present the results of the ab initio theoretical study of the structural, electronic, optical and thermal properties for CaFX (X= Cl, Br and I) compounds in its matlockite-type structure used the full-potential linearized augmented plane-wave (FP-LAPW) [1] method as implemented in WIEN2K code [1]. We used the generalized gradient approximation (GGA) [1] based on exchange–correlation energy optimization to calculate the total energy. Moreover, the modified Becke-Johnson potential (TB-mBJ) [1] was also applied to improve the electronic band structure calculations. Ground state properties such as the lattice parameters, c/a ratio, bulk modulus, pressure derivative of the bulk modulus and cohesive energy are calculated as well as the optimized internal parameters, by relaxing the atomic position in the force directions. The variations of the calculated inter atomic distances and angles between different atomic bonds are discussed. The electronic band structure, density of states and charge density calculations show that these compounds are ionic insulators.
Keywords: FP-LAPW method; matlockite-type structure; Structural and electronic properties.
References
[1] G.K.H. Madsen, P. Blaha, K. Schwarz, E. Sjöstedt, L. Nordström, Phys. Rev. B 64, 195134 (2001)
[2] P. Blaha, K. Schwarz, G.K.H. Madsen, D. Kvasnicka, J. Luitz, Wien2k, An Agmented Plane Wave Plus Local Orbitals Program for Calculating Crystal Properties, Vienna University of Technology, Austria (2001)
[3] J.P. Perdew, K. Burke, M. Ernzerhof, Phys. Rev. Lett. 77 (1996).
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