Измерительная установка для исследования и визуализации явления перколяции в неупорядоченных моделях нанокомпозитов металл-диэлектрик

The study uses the phenomenon of high voltage partial discharge to investigate the phenomenon of percolation and visualisation of the percolation channel. The phenomenon of partial discharges is very similar to the quantum tunneling phenomenon observed in metal-dielectric nanocomposites. In both cases the flow of alternating current occurs in the absence of direct contact between the metallic phase particles. A measuring stand was developed and constructed to test models of metal dielectric nanocomposites using high voltage partial discharge. The stand consists of a 110 kV high voltage transformer, a voltage regulator protecting the constant rate of high voltage rise, a measuring system consisting of a measuring probe, voltmeters and a computer. The communication between the measuring probe and the voltmeter was made in digital technology with the use of fiber optic technology, which allowed the meter to communicate with the computer without any errors and eliminated the interference caused by a strong electromagnetic field resulting from the use of high voltage. Systems modelling metal-dielectric composites were built, consisting of metallic elements in the form of disks, randomly distributed on the surface of the dielectric matrix. The number of disks was increased in series of 40 in each. The maximum number of disks was 1520. The dependence was determined of one of the important parameters characterising an partial discharge, i. e. the initial voltage, at which an electric current starts to flow between electrodes, on the concentration of the metallic phase. On the basis of these results, a percolation threshold was established for a matrix with a random distribution of metallic phase elements, the value of which is about 50 %. Films and pictures of partial discharges with visible percolation channels were taken with the camera with which the stand was equipped

Historical seismograms: Preserving an endangered species

AbstractThe youth of seismology as a science, compared to the typical duration of seismic cycles, results in a relative scarcity of records of large earthquakes available for processing by modern analytical techniques, which in turn makes archived datasets of historical seismograms extremely valuable in order to enhance our understanding of the occurrence of large, destructive earthquakes. Unfortunately, the value of these datasets is not always perceived adequately by decision-making administrators, which has resulted in the destruction (or last-minute salvage) of irreplaceable datasets.We present a quick review of the nature of the datasets of seismological archives, and of specific algorithms allowing their use for the modern retrieval of the source characteristics of the relevant earthquakes. We then describe protocols for the transfer of analog datasets to digital support, including by contact-less photography when the poor physical state of the records prevents the use of mechanical scanners.Finally, we give some worldwide examples of existing collections, and of successful programs of digital archiving of these valuable datasets

Doctor of Philosophy

dissertationIt is well documented that more than 50% of all human cancers have a mutated p53 gene status, rendering it inactive. The resulting tumor-derived p53 variants, similar to wild-type (wt) p53, retain their ability to oligomerize via the tetramerization domain. Upon hetero-oligomerization, mutant p53 enforces a dominant negative effect over active wt-p53 in cancer cells. To overcome this barrier, we have designed a chimeric superactive p53 (p53-CC) with an alternative oligomerization domain (CC) from breakpoint cluster region (Bcr). This approach led to the hypothesis that swapping the oligomerization domain of p53 with an alternative oligomerization domain will prevent hetero-oligomerization and transdominant inhibition by mutant p53 in cancer cells. The tumor suppressor activity of the chimeric p53-CC was evaluated in vitro and found to be similar to that of wt-p53 regardless of cancer type or endogenous p53 status. However, co-immunoprecipitation and viral transduction of p53-CC and wt-p53 into a breast cancer cell line that harbors a tumor derived transdominant mutant p53 validated that p53-CC indeed evades sequestration and consequent transdominant inhibition by endogenous mutant p53. Following proof-of-concept studies, the superior tumor suppressor activity of p53-CC and its ability to cause tumor regression of the MDA-MB-468 aggressive p53-dominant negative breast cancer tumor model was demonstrated in vivo. In addition, the underlying differential mechanisms of activity for p53-CC and wt-p53 delivered using viral-mediated gene therapy approach in the MDA-MB-468 tumor model were investigated. Finally, since domain swapping to create p53-CC could result in p53-CC interacting with endogenous Bcr, which is ubiquitous in cells, modifications on the CC domain were necessary to minimize potential interactions with Bcr. Hence, the possible design of mutations that will improve homo-dimerization of CC mutants and disfavor hetero-oligomerization with wild-type CC (CCwt) were investigated, with the goal of minimizing potential interactions with endogenous Bcr in cells. Indeed, the resulting lead candidate p53-CCmutE34K-R55E avoided binding to endogenous Bcr and retained p53 tumor suppressor activity. Although breast cancer was the main focus of this dissertation, the application of this research extends to many other types of cancer, including the deadliest cancers (pancreatic, lung, and ovarian), which currently lack effective treatments

Simulation Modeling and Analysis of F-16 Pilot Training Squadron

The need for fighter pilots in the Turkish Air Force is expected to increase with the planned acquisition of Joint Strike Fighters, ongoing new F-16 purchases, and other upgrades to the Turkish Air Force fighter inventory. This increased demand will affect the current fighter training squadron curriculum and scheduling. This study focuses on issues related to 143rd Oncel squadron F-16 Pilot Training with this projected increase in number of student pilots (SP). Completing the training periods on time is an important issue along with maintaining effective training performance. In our study the Total Time of the training period serves as our primary performance measure. Simulation modeling concepts are applied to examine the training period based on the squadron syllabus. After constructing a simulation model using Arena, Design of experiment, Regression Analysis and Metamodeling are implemented to capture the effects of the major factors, including SP, Instructor Pilot, Bandit and F-16, and how they interact with each other. The utilization of IP and Bandits is also examined as a performance measure. In addition we conduct a sensitivity analysis using our model with the current 143rd Oncel squadron resources

Pilot Shortage: Sustainability Perspective

Air transport is recently going through an exponential economic growth (ICAO, 2016). Similarly, industry forecast reports predict an upward trend for the next 20 years (Boeing, 2015). While these forecasts offer many opportunities, there are concerns as to whether or not this growth is sustainable. Defined as meeting “the needs of the present without compromising the ability of future generations to meet their needs”, sustainable development (SD), also adopted by United Nations (UN), brings more comprehensive approach to the subject (WCED, 1987, p. 43). The SD envisions a “balanced strategy” among economic (profit), social (people) and environmental (planet) domains, also known as “triple bottom line” (Elkington et al., 2007, p. 1). This balanced strategy can be represented in various ways reflecting interactions among three domains (Lozano, 2008). As holding a vision of going beyond present in terms of both time and place, SD emphasizes multi-dimensional thinking through three domains. From a sustainability perspective, the global pilot shortage becomes one of the most relevant subjects in the air transport industry. Since the pilot supply directly impacts aviation operations, it has substantial reflections on SD domains, especially economic and social. In this regard, predicted pilot scarcity, which may get worse with global competition attracting more pilots, has negative impacts on global and local markets. Considering interconnected nature of industries on a global scale, the impact of pilot shortage likely influences related industries, such as tourism, trade, customer services, etc. with much greater magnitudes impacting direct and indirect aviation jobs (ATAG, 2016). Additionally, air transport contributes to people’s mobility with its high connectivity. Thus, economic and social domains may directly be affected as a result of points mentioned above. As a global commitment, UN announced 17 “Sustainable Development Goals (SDGs)” for sustainable shared future in 2015. In this context, Air Transport Action Group’s Report (2016) is an analysis of air transport through SDGs. Similarly, reviewing the pilot shortage through SD perspective emerges as a need in academia so as to enable better appreciation of underlying origins of pilot shortage and sustainable solutions in addition to current studies (Higgins et al., 2013; Lutte and Lovelace, 2017). Sustainability concept may enable more systematic approaches to the formulation and attainment of SDGs. Besides, reexamining specific SDGs of “gender equality”, “economic growth” and “partnership” may contribute to the current discussions within aviation. This paper aims to review the pilot shortage with sustainability perspective and reflect on for possible scenarios and solutions. References: ATAG – Air Transport Action Group. (2016). Aviation: Benefits Beyond Borders. Geneva. Boeing. (2015). Current Market Outlook 2015-2034. Boeing.Com, 30. Elkington, J., Tickell, S., and Lee, M., (2007). 20 Years of global leadership. London: SustainAbility. Higgins, J., Lovelace, K., Bjerke, E., Lounsberry, N., Lutte, R., Friedenzohn, D., Craig, P. (2013). An Investigation of the United States Airline Pilot Labor Supply, (June), 36. ICAO. (2016). ICAO Long-Term Traffic Forecasts Passenger and Cargo, (July). Lozano, R. (2008). Envisioning sustainability three-dimensionally. Journal of Cleaner Production, 16(17), 1838-1846. Lutte, R., & Lovelace, K. (2017). Airline Pilot Supply in the US: Factors Influencing the Collegiate Pilot Pipeline. Journal of Aviation Technology & Engineering, 6(2), 53. WCED. (1987). Our Common Future. World Commission on Environment and Development. Oxford: Oxford University Press

Application of normal mode theory to seismic source and structure problems: Seismic investigations of upper mantle lateral heterogeneity

The theory of the normal modes of the earth is investigated and used to build synthetic seismograms in order to solve source and structural problems. A study is made of the physical properties of spheroidal modes leading to a rational classification. Two problems addressed are the observability of deep isotropic seismic sources and the investigation of the physical properties of the earth in the neighborhood of the Core-Mantle boundary, using SH waves diffracted at the core's surface. Data sets of seismic body and surface waves are used in a search for possible deep lateral heterogeneities in the mantle. In both cases, it is found that seismic data do not require structural differences between oceans and continents to extend deeper than 250 km. In general, differences between oceans and continents are found to be on the same order of magnitude as the intrinsic lateral heterogeneity in the oceanic plate brought about by the aging of the oceanic lithosphere

Измерительная установка для исследования и визуализации явления перколяции в неупорядоченных моделях нанокомпозитов металл-диэлектрик

The study uses the phenomenon of high voltage partial discharge to investigate the phenomenon of percolation and visualisation of the percolation channel. The phenomenon of partial discharges is very similar to the quantum tunneling phenomenon observed in metal-dielectric nanocomposites. In both cases the flow of alternating current occurs in the absence of direct contact between the metallic phase particles.A measuring stand was developed and constructed to test models of metal dielectric nanocomposites using high voltage partial discharge. The stand consists of a 110 kV high voltage transformer, a voltage regulator protecting the constant rate of high voltage rise, a measuring system consisting of a measuring probe, voltmeters and a computer. The communication between the measuring probe and the voltmeter was made in digital technology with the use of fiber optic technology, which allowed the meter to communicate with the computer without any errors and eliminated the interference caused by a strong electromagnetic field resulting from the use of high voltage.Systems modelling metal-dielectric composites were built, consisting of metallic elements in the form of disks, randomly distributed on the surface of the dielectric matrix. The number of disks was increased in series of 40 in each. The maximum number of disks was 1520. The dependence was determined of one of the important parameters characterising an partial discharge, i. e. the initial voltage, at which an electric current starts to flow between electrodes, on the concentration of the metallic phase. On the basis of these results, a percolation threshold was established for a matrix with a random distribution of metallic phase elements, the value of which is about 50 %. Films and pictures of partial discharges with visible percolation channels were taken with the camera with which the stand was equipped.В статье для исследования явления перколяции и визуализации каналов перколяции использован высоковольтный частичный пробой. Частичный пробой очень похож на квантовое явление туннелирования, наблюдаемое в нанокомпозитах металл-диэлектрик. Как в первом, так и во втором случаях для протекания электрического тока не требуется контакт между частицами металлической фазы.Разработана и изготовлена измерительная установка, предназначенная для измерений моделей нанокомпозитов металл-диэлектрик с использованием высоковольтного частичного пробоя. В состав установки входят: высоковольтный трансформатор с максимальным напряжением до 110 кВ, регулятор напряжения первичной обмотки высоковольтного трансформатора, обеспечивающий постоянную скорость увеличения напряжения, измерительный зонд, вольтметры и компьютер. Сигналы от зонда и вольтметра с целью ограничения помех, связанных с сильным электрическим полем, передаются с использованием оптоэлектронного кабеля.Разработаны и изготовлены двумерные модели нанокомпозитов, в которых частицы металлической фазы в форме металлических дисков размещены случайным образом на поверхности диэлектрической матрицы. Число металлических дисков во время измерений увеличивалось по 40 штук в серии до максимальной величины 1520.Определена зависимость от концентрации металлической фазы одного из существенных параметров высоковольтного частичного пробоя – пороговое напряжение, выше которого между электродами начинает течь ток. На основании этих измерений определён порог перколяции для матрицы со случайным распределением элементов металлической фазы.С помощью фотоаппарата, входящего в состав установки, зарегистрированы фильмы и фотографии явления частичного пробоя между элементами металлической фазы моделей, на которых видны каналы перколяции