03.NU Research and Innovation System
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Item Open Access Multiscale simulation models of Xe bubble formation in irradiated Mo(Transactions of the American Nuclear Society, 2012) Starikov, S. V.; Yun, D.; Yacout, A. M.; Insepov, Z.Multiscale simulation models for Xe bubble nucleation and growth in irradiated Mo were developed that consist Ab-initio calculations of the interatomic potentials for the Mo and Xe-Mo systems, atomistic MD simulations of the kinetic rate coefficients of radiation defects, and nucleation mechanisms of Xe bubbles in Mo. Simulations of various Xe concentrations, temperatures and pressures were carried out. A critical concentration of Xe atoms was determined at which the nucleation occurs spontaneously.Item Open Access Atomistic and Kinetic Simulations of Radiation Damage in Molybdenum(2012 MRS Spring Meeting, 2012-04) Rest, J.; Yacout, A. M.; Ye, B.; Yun, D.; Kuksin, A. Y.; Norman, G. E.; Stegailov, V. V.; Yanilkin, A. V.; Insepov, Z.A new Mo potential, developed recently by using an ab initio quantum mechanics theory, was used to study formation and time evolution of radiation defects, such as self-interstitial atoms (SIAs), vacancies, and small clusters of SIAs, using molecular dynamics (MD). MD models were developed for calculation of the diffusion coefficients of vacancies, self-interstitials, and small dislocation loops containing 2 to 37 SIAs; and the rate constants were calculated. Interactions of small SIA loops with SIAs were simulated. The results show that rotation of SIA from one 〈111〉 to another equivalent direction is an important mechanism that significantly contributes to kinetic coefficients.Item Open Access Systems-Level Characterization of Microchannel Plate Detector Assemblies, using a Pulsed sub-Picosecond Laser(Physics Procedia, 2012-12-31) Wetstein, M.; Adams, B.; Chollet, Matthieu; Webster, Preston; Jokela, Slade; Veryovkin, Igor; Zinovev, Alex; Elam, Jeffrey; Mane, Anil; Peng, Qing; Frisch, Henry; Insepov, Z.; Wetstein, Matthew J.Abstract Microchannel plate photomultiplier tubes (MCP-PMTs) are compact imaging detectors, capable of micron-level spatial imaging and timing measurements with resolutions well below 10 picoseconds. The Large Area Picosecond Photodetector Collaboration (LAPPD) is developing techniques for fabricating 8“x8”, thin, planar, glass-body MCP-PMTs at costs comparable to traditional PMTs. Collaboration between the High Energy Physics Division and the Advanced Photon Source (APS) at Argonne National Laboratory (ANL) has produced an advanced channel-plate characterization facility for testing the time response of MCPs using a pulsed laser capable of sub-picosecond pulses. The MCPs are tested in stacks of one or two plates with a simple photocathode and coupled to a microstripline anode board. LAPPD-made MCPs have already demonstrated gains larger than 105 and promising time resolving capabilities. These measurements will guide the systems-level optimization of LAPPD detectors and the development of signal processing algorithms. Predictions made by the LAPPD simulations group based on electron emmission properties of the MCP pore surface are compared with these tests to help further our understanding of MCP performance.Item Metadata only Using Von Mises-fisher Distribution for Polymer Conformation Analysis in Multi-scale Framework(2013-01-01) Abzhanov, Aidos; Kallemov, Bakytzhan; Aidos, AbzhanovAbstract In this study we consider the statistical representation of polymer conformations, which is very important when modeling rheology at macroscopic scales. It is impossible to track all relevant microscopic variables for each polymer in a polymer-laden solution due to the huge number degrees of freedom associated with such fluids. We applied this approach to one of the most descriptive kinetic models of polymer, Kramers bead-rod model, where the probability density function models the angle of each rod with respect to the fixed coordinate axes. Towards this goal we apply mixture of von Mises-Fisher distribution for modeling a polymer conformation. The Expectation-Maximization based clustering algorithms are used to estimate the conformation given the ensemble of polymers. Both distribution sampling and parameters estimation have been implemented in parallel using CPU and GPU based platforms.Item Restricted A ternary EAM interatomic potential for U-Mo alloys with xenon(Modelling and Simulation in Materials Science and Engineering, 21(3), 2013-04) Smirnova, D.E.; Kuksin, A. Y.; Starikov, S. V.; Stegailov, V. V.; Rest, J.; Yacout, A. M.; Insepov, Z.A new interatomic potential for a uranium-molybdenum system with xenon is developed in the framework of an embedded atom model using a force-matching technique and a dataset of ab initio atomic forces. The verification of the potential proves that it is suitable for the investigation of various compounds existing in the system as well as for simulation of pure elements: U, Mo and Xe. Computed lattice constants, thermal expansion coefficients, elastic properties and melting temperatures of U, Mo and Xe are consistent with the experimentally measured values. The energies of the point defect formation in pure U and Mo are proved to be comparable to the density-functional theory calculations. We compare this new U-Mo-Xe potential with the previously developed U and Mo-Xe potentials. A comparative study between the different potential functions is provided. The key purpose of the new model is to study the atomistic processes of defect evolution taking place in the U-Mo nuclear fuel. Here we use the potential to simulate bcc alloys containing 10 wt% of intermetallic Mo and U2Mo.Item Restricted In situ TEM investigation of Xe ion irradiation induced defects and bubbles in pure molybdenum single crystal(Journ al of Nuclear Materials, 2013-06-30) Yun, D.; Kirk, Marquis A.; Baldo, Peter M.; Rest, J.; Yacout, A. M.; Insepov, Z.; Yun, DiAbstract In order to study irradiation damage and inert gas bubble formation and growth behaviors, and to provide results and insights useful towards the validation of a multi-scale simulation approach based on a newly developed Xe–Mo inter-atomic potential, in situ Transmission Electron Microscopy (TEM) studies of Xe implantations in pure single crystal Molybdenum (Mo) have been conducted. 300keV and 400keV Xe+ ion beams were used to implant Xe in pre-thinned TEM Mo specimens. The irradiations were conducted at 300°C and 600°C to ion fluence up to 4×1016ions/cm2.In situ TEM characterization allows detailed behaviors of defect clusters to be observed and is very useful in illustrating defect interaction mechanisms and processes. Dislocation loops were found to form at relatively low irradiation fluence levels. The characterization results showed that the free surfaces, formed in the process of producing pre-thinned specimens, play an important role in influencing the behaviors of dislocation loops. Similar characterizations were conducted at high fluence levels where Xe gas bubbles can be clearly observed. Xe gas bubbles were observed to form by a multi-atom nucleation process and they were immobile throughout the irradiation process at both temperatures. Measurements on both the number density and the size of dislocation loops and gas bubbles were taken. The results and implications of the measurements are discussed in this paper.Item Metadata only Three-dimensional imaging of polymer materials by Scanning Probe Tomography(2014-03-01) Alekseev, Alexander; Efimov, Anton; Loos, Joachim; Matsko, Nadejda; Syurik, Julia; Alexander, AlekseevAbstract Scanning Probe Tomography (SPT) is a new method for nanoscale volume imaging of sample morphology and property distribution based on Scanning Probe Microscopy (SPM). In this review we describe and discuss recent results obtained with different SPT techniques on polymer samples. The design of the existing SPM based instruments used for tomography in principle allows for volume reconstruction of any kind of mechanical, functional or chemical property distribution, which can be measured by SPM. We describe some recent volume reconstruction results from several types of polymer materials and critically discuss limitations and future prospects of SPM tomography.Item Open Access Intelligent voice system for kazakh(Journal of Physics: Conference Series, 2014-04-04) Yessenbayev, Z.; Saparkhojayev, N.; Tibeyev, T.Modern speech technologies are highly advanced and widely used in day-to-day applications. However, this is mostly concerned with the languages of well-developed countries such as English, German, Japan, Russian, etc. As for Kazakh, the situation is less prominent and research in this field is only starting to evolve. In this research and applicationoriented project, we introduce an intelligent voice system for the fast deployment of callcenters and information desks supporting Kazakh speech. The demand on such a system is obvious if the country’s large size and small population is considered....Item Open Access Optical Emission of the Nuclear-Induced Plasmas of Gas Mixtures(International Journal of Optics, 2014-04-24) Khasenov, Mendykhan U.The characteristic properties of the inverted-population-forming processes in lasers with ionizing pumping are considered. Results obtained fromresearch of active lasermedia concerning the p-s transitions of atoms of neon, mercury, and cadmium are presented. The feasibility of ion-ion recombination in lasers with nuclear pumping is discussed. The excitation kinetics of the first negative system of CO, heteronuclear ionic molecules of inert gases, and halogenides of inert gases under ionizing radiation are considered.Item Metadata only Corrigendum to “Three-dimensional imaging of polymer materials by scanning probe tomography” [Eur. Polym. J. 52 (2014) 154–165](2014-06-01) Alekseev, Alexander; Efimov, Anton; Loos, Joachim; Matsko, Nadejda; Syurik, Julia; Alexander, AlekseevItem Open Access Cooperation benefits of Caspian countries in their energy sector development(2014-08-01) De Miglio, Rocco; Akhmetbekov, Yerbol; Baigarin, Kanat; Bakdolotov, Aidyn; Tosato, GianCarlo; Rocco, De MiglioAbstract This paper studies the development possibilities of the energy systems of four Central Asia and Caspian countries. It explores options that improve their domestic energy efficiencies and increase their export of fossil energy commodities. Using the MARKAL-TIMES modelling tool, it represents their energy system with a bottom-up partial economic equilibrium growth model. With the help of scenario analyses, it evaluates the direct economic advantage of improving the domestic energy efficiencies. Furthermore it calculates the direct economic advantage of cooperation. It finds out that a new/different geo-economic attitude brings USD billions of annual economic benefits, particularly if the countries aim to differentiate their export routes, increase the amount of export and contribute to climate change mitigation.Item Restricted A multiscale method for the analysis of defect behavior in Mo during electron irradiation(Computational Materials Science, 2014-10-31) Rest, J.; Ye, B.; Yun, D.; Insepov, Z.; Rest, J.Abstract In order to overcome a lack of experimental information on values for key materials properties and kinetic coefficients, a multiscale modeling approach is applied to defect behavior in irradiated Mo where key materials properties, such as point defect (vacancy and interstitial) migration enthalpies as well as kinetic factors such as dimer formation, defect recombination, and self interstitial–interstitial loop interaction coefficients, are obtained by molecular dynamics calculations and implemented into rate-theory simulations of defect behavior. The multiscale methodology is validated against interstitial loop growth data obtained from electron irradiation of pure Mo. It is shown that the observed linear behavior of the loop diameter vs. the square root of irradiation time is a direct consequence of the 1D migration of self-interstitial atoms.Item Open Access Photon propagation in slowly varying inhomogeneous electromagnetic fields(American Physical Society, 2015-04) Karbstein, Felix; Shaisultanov, RashidStarting from the Heisenberg-Euler effective Lagrangian, we determine the photon current and photon polarization tensor in inhomogeneous, slowly varying electromagnetic fields. To this end, we consider background field configurations varying in both space and time, paying special attention to the tensor structure. As a main result, we obtain compact analytical expressions for the photon polarization tensor in realistic Gaussian laser pulses, as generated in the focal spots of high-intensity lasers. These expressions are of utmost importance for the investigation of quantum vacuum nonlinearities in realistic high-intensity laser experiments.Item Open Access ZERO CARBON FUTURE: CHALLENGE AND OPPORTUNITY FOR RESEARCH AND INDUSTRIAL APPLICATIONS(National Inter-University Consortium for Telecommunications. International Scientific and University Conference. "Climate Change and CO2 Emission Reduction", 2015-07-13) Vernazza, GianniItem Metadata only Using pyridal[2,1,3]thiadiazole as an acceptor unit in a low band-gap copolymer for photovoltaic applications(2015-08-01) Ibraikulov, Olzhas A.; Bechara, Rony; Chavez, Patricia; Bulut, Ibrahim; Tastanbekov, Dias; Leclerc, Nicolas; Hebraud, Anne; Heinrich, Benoît; Berson, Solenn; Lemaitre, Noëlla; Chochos, Christos L.; Lévêque, Patrick; Heiser, Thomas; Olzhas A., IbraikulovAbstract In this report, we explore the optoelectronic properties of a low band-gap copolymer based on the alternation of electron rich (thiophene and thienothiophene units) and electron deficient units (pyridal[2,1,3]thiadiazole (Py)). Initial density functional theory calculations point out the interest of using the Py unit to optimize the polymer frontier orbital energy levels. A high molecular weight (Mn=49kg/mol) solution-processable copolymer, based on Py, thiophene and thienothiophene units, has been synthesized successfully. From cyclic-voltammetry and UV–visible absorption measurements a relatively deep HOMO level (−5.1eV) and an optical band-gap (1.48eV) have been estimated. Charge transport both in horizontal and vertical directions were extracted from field-effect transistors and space charge limited current diodes, respectively, and led to a relatively high in-plane hole mobility in pure polymer films (0.7×10−2cm2V−1s−1). GIWAXS results showed almost identical in-plane lamellar morphologies, with similar average size and orientation of the polymer crystalline domains in both, pure polymer films and polymer:fullerene blends. Also, the gate-voltage dependence of the field-effect mobility revealed that the energy disorder in the polymer domains was not altered by the introduction of fullerenes. The nevertheless significantly higher out-of-plane hole mobility in blends, in comparison to pure polymer films, was attributed to the minor amorphous polymer phase, presumably localized close to the donor/acceptor interface, whose signature was observed by UV–vis absorption. Promising photovoltaic performances could be achieved in a standard device configuration. The corresponding power conversion efficiency of 4.5% is above the value achieved previously with a comparable polymer using benzo [2,1,3]thiadiazole instead of Py as acceptor unit.Item Metadata only Computer simulation and visualization of supersonic jet for gas cluster equipment(2015-09-21) Ieshkin, A.; Ermakov, Y.; Chernysh, V.; Ivanov, I.; Kryukov, I.; Alekseev, K.; Kargin, N.; Insepov, Z.; A., IeshkinAbstract Supersonic nozzle is a key component of a gas cluster condensation system. We describe a flow visualization system using glow discharge with annular or plane electrodes. The geometric parameters of a supersonic jet under typical conditions used in a gas cluster ion beam accelerator are investigated. As well numerical simulations were performed. Dependence of inlet and ambient pressures and nozzle throat diameter on the shock bottle dimensions is described for different working gases. Influence of condensation rate on shock bottle axial size is discussed.Item Open Access Computer simulation and visualization of supersonic jet for gas cluster equipment(Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2015-09-21) Ermakov, Y.; Chernysh, V.; Ivanov, I.; Ieshkin, A.; Kryukov, I.; Alekseev, K.; Kargin, N.; Insepov, Z.; Ieshkin, A.Abstract Supersonic nozzle is a key component of a gas cluster condensation system. We describe a flow visualization system using glow discharge with annular or plane electrodes. The geometric parameters of a supersonic jet under typical conditions used in a gas cluster ion beam accelerator are investigated. As well numerical simulations were performed. Dependence of inlet and ambient pressures and nozzle throat diameter on the shock bottle dimensions is described for different working gases. Influence of condensation rate on shock bottle axial size is discussed.Item Open Access КОРПОРАТИВНЫЕ R&D ЦЕНТРЫ: Платформа для устойчивого роста бизнеса(ЧУ «Nazarbayev University Research and Innovation System», 2016) Жакупов, А. Б.; Султангазин, Б. Н.; Утегулов, А. К.; Тулегенова, Г. Е.; Алтынбеков, А. А.Настоящий обзор посвящен анализу деятельности корпоративных центров исследований и разработок (R&D) в мире. В частности, проведен сравнительный анализ различных моделей корпоративных R&D, включающий в себя описание эволюции данных моделей за последние 60 лет, опыт применения принципов открытых инноваций и реализации инновационных стратегий компаний. В обзоре также рассмотрены актуальные вопросы организации R&D деятельности в крупных компаниях, такие, как модель управления R&D, управление портфелем инновационных проектов, вопросы коммерциализации результатов исследований и разработок, проблемы, связанные с инфраструктурой и расположением R&D центра, и, один из самых важных вопросов — вопрос обеспечения кадрами. Завершается обзор целостными кейсами — лучшими практиками R&D на примере шести крупных компаний из разных отраслей. Настоящее издание рассчитано на широкий круг казахстанских и зарубежных читателей — лидеров крупного и среднего бизнеса, представителей государственных органов, институтов развития и других организаций, вовлеченных в процесс развития инновационной деятельности вокруг крупных корпоративных R&D центровItem Open Access Cosmic Growth and Expansion Conjoined(International conference "ECL17: Exploring the Energetic Universe 2017", Nazarbayev University Energetic Cosmic Laboratory, 2016-10-17) Linder, Eric V.Cosmological measurements of both the expansion history and growth history have matured, and the two together provide an important test of general relativity. We consider their joint evolutionary track, showing that this has advantages in distinguishing cosmologies relative to considering them individually or at isolated redshifts. In particular, the joint comparison relaxes the shape degeneracy that makes f 8(z) curves difficult to separate from the overall growth amplitude. The conjoined method further helps visualization of which combinations of redshift ranges provide the clearest discrimination. We examine standard dark energy cosmologies, modified gravity, and “stuttering” growth, each showing distinct signatures.Item Open Access The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: Constraining modified gravity(American Physical Society, 2016-12-02) Mueller, Eva-Maria; Percival, Will; Linder, Eric; Alam, Shadab; Zhao, Gong-Bo; Sanchez, Ariel G.; Beutler, FlorianWe use baryon acoustic oscillation and redshift space distortion from the completed Baryon Oscillation Spectroscopic Survey, corresponding to data release 12 of the Sloan Digital Sky Survey, combined sample analysis in combination with the cosmic microwave background, supernova and redshift space distortion measurements from additional spectroscopic surveys to test deviations from general relativity. We present constraints on several phenomenological models of modified gravity.