220 research outputs found
Inter-vortex spacing in superfluid turbulence: temperature and Reynolds number dependences
No full textThe typical spacing between superfluid vortices in an isothermal turbulent tangle is proportional to the integral scale H rescaled by the quantum Reynolds number Re_K=H.V/K to the power of 3/4, where K is the quantum of circulation around of single vortex [Salort et al.,EPL 2011]. This empirical relation can be seen as the quantum-turbulence version of the corresponding well-know equation giving Kolmogorov dissipative scale in classical turbulence. In 2014, we studied the temperature dependence of the numerical factor (d/H).Re_K^{3/4} in 4He by joint numerical and experimental analysis of steady state turbulence over a wide temperature interval (1.2 - 2.16 K) [Babuin et al., EPL 2014]. Agreement between the two analyses was found good except at the very ends of this temperature interval. We will discuss this issue by presenting additional experimental data obtained by post-processing of superfluid experiments published between 1975 and 1998
From ornament to essence - represented by Gustav Klimt and Egon Schiele
No full textGraduate research paper for painting.AR 695, H.V.1979 Spring
ЕФЕКТИВНІСТЬ ВИКОРИСТАННЯ ТЕПЛОАКУМУЛЮЮЧИХ СИСТЕМ У СКЛАДІ ЕНЕРГЕТИЧНИХ УСТАНОВОК СУДЕН РІЗНОГО ПРИЗНАЧЕННЯ
No full textOne of the topical areas of reducing fuel consumption and harmful substances into the environment is the additional use of thermal energy storage systems based on phase-change thermal energy storages as part of marine power plants, which allow pre-start up engine preparation and general vessel needs. The aim of the research is to determine the thermal energy storage systems efficient use indicators for pre-start up engine preparation and sanitary needs of personnel onboard under conditions of different marine power plants operational cycles. For three types of vessels, namely a cruise ship, a bulk carrier and a tanker, respectively, the use of thermal energy storage systems as part of diesel-electric and diesel plants is considered. The heat of exhaust gases from diesel engines was utilized in silencers-thermal energy storages with a phase change. The energy efficiency of the studied thermal energy storage systems was determined by the heat utilization and relative fuel economy, taking into account the selected materials and operating cycles of marine power plants. The use of thermal energy storage systems in marine diesel-electric and diesel plants at the expense of waste heat from exhaust gases has made it possible to expand the functionality of meeting the needs of power plants and personnel. As a result of mathematical modelling, a database was obtained to recommend the optimal choice of design solutions and operational characteristics of marine power plants with thermal energy storage systems. The use of the selected thermal energy storage materials in the thermal energy storage systems allows to obtain relative fuel savings per voyage on the level from 0.3 to 0.6% for the cruise ship, respectively. When using thermal energy storage system as part of the bulk carrier and tanker marine power plants with selected thermal energy storage materials for pre-start up preparation of the main engine and sanitary needs, the relative fuel savings per voyage is lower than for the cruise ship. So the possibility of more efficient use of thermal energy storage systems in these vessels requires coordination, which is associated with additional needs during the voyage.Одним з актуальних напрямків зменшення витрати палива та шкідливих речовин у навколишнє середовище є додаткове використання в складі суднових енергетичних установок теплоакумулюючих систем на базі теплових акумуляторів з фазовим переходом, що дозволяють забезпечити передпускову підготовку двигунів та загальносуднові потреби. Метою дослідження є визначення показників ефективного використання теплоакумулюючих систем для передпускової підготовки двигунів та санітарно-побутових потреб персоналу на борту судна в умовах різних експлуатаційних циклів суднових енергетичних установок. Для трьох типів суден, а саме круїзного лайнера, балкеру і танкеру відповідно розглянуто використання теплоакумулюючих систем у складі дизель-електричної та дизельних установок. Утилізація теплоти відпрацьованих газів дизельних двигунів здійснювалася в глушниках-теплоакумуляторах з фазовим переходом. Енергоефективність використання досліджених теплоакумулюючих систем визначалася показниками використання теплоти та відносної економії палива з урахуванням вибраних теплоакумулюючих матеріалів та експлуатаційних циклів суднових енергетичних установок. Використання в суднових дизель-електричних та дизельних установках теплоакумулюючих систем за рахунок скидної теплоти відпрацьованих газів дозволило розширити функціональні можливості забезпечення потреб енергетичних установок та персоналу. В результаті математичного моделювання отримано базу даних для рекомендації оптимального вибору проектних рішень та експлуатаційних характеристик суднових енергетичних установок з теплоакумулюючими системами. Використання в теплоакумулюючих системах вибраних матеріалів дозволяє отримати відносну економію палива за рейс на рівні 0,3…0,6% для круїзного лайнера. При використанні теплоакумулюючих систем в складі суднових енергетичних установок балкеру та танкеру з вибраними теплоакумулююючими матеріалами для передпускової підготовки головного двигуна та санітарно-побутових потреб відносна економія палива нижче ніж для круїзного лайнеру. Тому більш ефективне використання теплоакумуюючих систем у даних суднах потребує узгодження з додатковими потребами при здійсненні рейсу
2050 Midwest Structural Masterplan & A Transit Hub for St Louis
No full textThe project initiated with researching the condition of the Midwest, it’s major challenges and potential opportunities within the themes of infrastructure, energy, and landscape. After 5 months of research and analysis, the studio produced a 2050 Structural Masterplan for the Midwest. This masterplan involved a strategy for creating a unified, economically strengthened region along with a set of proposals that highlighted potential solutions to some of the specified challenges. This was executed through the lens of large-scale, top down, future vision planning in order to address very complex and challenging issues. Following the research and Masterplan design, each student selected their own site, project, and program within the context of the Midwest: a multi-modal transit hub (highlighting the increased value of passenger rail and the introduction of a maglev high speed rail) within St Louis (at the location of the existing passenger train station). The goal was to test the ideas of the 2050 Structural Masterplan of the Midwest within a city context and at a building scale. The St Louis Transit Hub focused on integrating multiple modes of transportation while providing a more inviting and welcoming experience into the city. This gateway experience became a guiding concept for the project, offering a gateway for the pedestrian, a gateway for the trains, and a symbolic gateway moment for the inhabitants of St Louis: a moment of passing from one mentality to another (an opportunity to offer education, awareness, and understanding about the challenges and opportunities). A gateway in three dimensions.MaterializationArchitectureArchitectur
Materializing Technologies: Surfacing Focal Things and Practices with Design
No full textToday, the world is populated with what we colloquially refer to as “black boxes.” These are technologies that perform sophisticated operations but obfuscate these complex operations, providing us with little context to what they do, how they work, and the role they play in our lives. In simple terms, this thesis addresses the following broadly framed questions: what parts of these black boxes should be made legible to the layperson? And regarding these parts: how can design be harnessed to reframe them as legible?Ethics & Philosophy of TechnologyHuman Information Communication Desig
Experiments on a natural circulation loop - from void fraction to nuclear
No full textApplied Science
Signal detection in fractional Gaussian noise and an RKHS approach to robust detection and estimation
No full textThis thesis is divided into two parts. In the first part, the problem of signal detection in fractional Gaussian noise is considered. To facilitate the study of this problem, several results related to the reproducing kernel Hilbert space of fractional Brownian motion are presented. In particular, this reproducing kernel Hilbert space is characterized completely and an alternative characterization for the restriction of this class of functions to a compact interval (0,T) is given. Infinite-interval whitening filters for fractional Brownian motion are also developed. Application of these results to the signal detection problem yields necessary and sufficient conditions for a deterministic or stochastic signal to produce a nonsingular shift when embedded in additive fractional Gaussian noise. Also, a formula for the likelihood ratio corresponding to any deterministic nonsingular shift is developed. Finally, some results concerning detector performance in the presence of additive fractional Gaussian noise are presented.In the second part of the thesis, the application of reproducing kernel Hilbert space theory to the problems of robust detection and estimation is investigated. It is shown that this approach provides a general and unified framework in which to analyze the problems of L\sp2 estimation, matched filtering, and quadratic detection in the presence of uncertainties regarding the second-order structure of the random processes involved. Minimax robust solutions to these problems are characterized completely, and some results concerning existence of robust solutions are presented.Made available in DSpace on 2011-05-07T14:14:57Z (GMT). No. of bitstreams: 2
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Difference-operator-based models in statistical signal processing
No full textDifference-operator-based models are an alternative to conventional shift-operator-based models for modeling stationary discrete-time random processes obtained by sampling continuous-time processes, when the sampling rate is rapid relative to the dynamics of the continuous-time process. In this regime, statistical signal processing procedures derived from the difference-operator-based models tend to be better-conditioned than their conventional analogues, resulting in better numerical performance when implemented using finite-precision arithmetic. Unlike the situation for shift-operator models, estimating the parameters of a difference-operator-based model involves solving a non-Toeplitz system of linear equations. We derive an algorithm for efficiently estimating these parameters, analogous to the Levinson algorithm for conventional models. Numerical results have been obtained that indicate that, in the presence of roundoff errors, the new algorithm gives better results than the Levinson algorithm. We also present a class of algorithms that solve for the model parameters by obtaining triangular factorizations of the covariance matrix of differenced data. These algorithms have the added advantage of not requiring the computation of any n-dimensional inner products, thus rendering them suitable for parallelization. They also suggest a lattice implementation of the modeling filter, in which the basic block is a discrete-time integrator, rather than a delay.Made available in DSpace on 2011-05-07T14:20:34Z (GMT). No. of bitstreams: 2
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Workshop on the implementation of the grand challenges
No full textThis is a pre-copyedited, author-produced PDF of an article accepted for publication in Integrative and Comparative Biology following peer review. The version of record [Tsukimura, B., H.V. Carey and D.K. Padilla. 2010. Workshop on the Implementation of the Grand Challenges. Intetgrative Comparative Biology 50: 945-947] is available online at: http://icb.oxfordjournals.org/content/50/6/945.full.https://doi.org/10.1093/icb/icq13
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