Augmented thermal bus wih multiple thermoelectric devices individually controlled

The present invention is directed to an augmented thermal bus. In the present design a plurality of thermo-electric heat pumps are used to couple a source plate to a sink plate. Each heat pump is individually controlled by a model based controller. The controller coordinates the heat pumps to maintain isothermality in the source

Convection equation modeling: A non-iterative direct matrix solution algorithm for use with SINDA

The determination of the boundary conditions for a component-level analysis, applying discrete finite element and finite difference modeling techniques often requires an analysis of complex coupled phenomenon that cannot be described algebraically. For example, an analysis of the temperature field of a coldplate surface with an integral fluid loop requires a solution to the parabolic heat equation and also requires the boundary conditions that describe the local fluid temperature. However, the local fluid temperature is described by a convection equation that can only be solved with the knowledge of the locally-coupled coldplate temperatures. Generally speaking, it is not computationally efficient, and sometimes, not even possible to perform a direct, coupled phenomenon analysis of the component-level and boundary condition models within a single analysis code. An alternative is to perform a disjoint analysis, but transmit the necessary information between models during the simulation to provide an indirect coupling. For this approach to be effective, the component-level model retains full detail while the boundary condition model is simplified to provide a fast, first-order prediction of the phenomenon in question. Specifically for the present study, the coldplate structure is analyzed with a discrete, numerical model (SINDA) while the fluid loop convection equation is analyzed with a discrete, analytical model (direct matrix solution). This indirect coupling allows a satisfactory prediction of the boundary condition, while not subjugating the overall computational efficiency of the component-level analysis. In the present study a discussion of the complete analysis of the derivation and direct matrix solution algorithm of the convection equation is presented. Discretization is analyzed and discussed to extend of solution accuracy, stability and computation speed. Case studies considering a pulsed and harmonic inlet disturbance to the fluid loop are analyzed to assist in the discussion of numerical dissipation and accuracy. In addition, the issues of code melding or integration with standard class solvers such as SINDA are discussed to advise the user of the potential problems to be encountered

Evaporation of Lennard-Jones Fluids

Evaporation and condensation at a liquid/vapor interface are ubiquitous interphase mass and energy transfer phenomena that are still not well understood. We have carried out large scale molecular dynamics simulations of Lennard-Jones (LJ) fluids composed of monomers, dimers, or trimers to investigate these processes with molecular detail. For LJ monomers in contact with a vacuum, the evaporation rate is found to be very high with significant evaporative cooling and an accompanying density gradient in the liquid domain near the liquid/vapor interface. Increasing the chain length to just dimers significantly reduces the evaporation rate. We confirm that mechanical equilibrium plays a key role in determining the evaporation rate and the density and temperature profiles across the liquid/vapor interface. The velocity distributions of evaporated molecules and the evaporation and condensation coefficients are measured and compared to the predictions of an existing model based on kinetic theory of gases. Our results indicate that for both monatomic and polyatomic molecules, the evaporation and condensation coefficients are equal when systems are not far from equilibrium and smaller than one, and decrease with increasing temperature. For the same reduced temperature $T/T_c$, where $T_c$ is the critical temperature, these two coefficients are higher for LJ dimers and trimers than for monomers, in contrast to the traditional viewpoint that they are close to unity for monatomic molecules and decrease for polyatomic molecules. Furthermore, data for the two coefficients collapse onto a master curve when plotted against a translational length ratio between the liquid and vapor phase.Comment: revised version, 15 pages, 15 figures, to appear in J. Chem. Phy

Use of a Closed-Loop Tracking Algorithm for Orientation Bias Determination of an S-Band Ground Station

The Space Communications and Navigation (SCaN) Testbed project completed installation and checkout testing of a new S-Band ground station at the NASA Glenn Research Center in Cleveland, Ohio in 2015. As with all ground stations, a key alignment process must be conducted to obtain offset angles in azimuth (AZ) and elevation (EL). In telescopes with AZ-EL gimbals, this is normally done with a two-star alignment process, where telescope-based pointing vectors are derived from catalogued locations with the AZ-EL bias angles derived from the pointing vector difference. For an antenna, the process is complicated without an optical asset. For the present study, the solution was to utilize the gimbal control algorithms closed-loop tracking capability to acquire the peak received power signal automatically from two distinct NASA Tracking and Data Relay Satellite (TDRS) spacecraft, without a human making the pointing adjustments. Briefly, the TDRS satellite acts as a simulated optical source and the alignment process proceeds exactly the same way as a one-star alignment. The data reduction process, which will be discussed in the paper, results in two bias angles which are retained for future pointing determination. Finally, the paper compares the test results and provides lessons learned from the activity

Optimal sequencing of a set of positive numbers with the variance of the sequence's partial sums maximized

We consider the problem of sequencing a set of positive numbers. We try to find the optimal sequence to maximize the variance of its partial sums. The optimal sequence is shown to have a beautiful structure. It is interesting to note that the symmetric problem which aims at minimizing the variance of the same partial sums is proved to be NP-complete in the literature.Comment: 12 pages;Accepted for publication in Optimization Lette

Оценка риска и расчет последствий разрушения резервуара хранения сжиженного газа на ООО «Томскнефтехим» г. Томск

Цель работы – оценка риска и расчет последствий разрушения резервуара на ООО "Томскнефтехим" г.Томск. В работе проведен литературный обзор по вопросам декларирования потенциально опасных объектов, проведен анализ аварийных ситуаций на нефтехимических предприятиях. Рассчитан индивидуальный, коллективный, пожарный риск, а также последствия разрушения резервуара для опасных исходов, выявленных на основе анализа дерева событий.The purpose of the work is to assess the risk and calculate the consequences of the destruction of the reservoir at OOO Tomskneftekhim, Tomsk. A literature review on the issues of declaring potentially hazardous facilities was conducted, an analysis of emergency situations at petrochemical enterprises was carried out. The individual, collective, fire risk, as well as the consequences of the destruction of the reservoir for dangerous outcomes, identified on the basis of the analysis of the event tree, are calculated

Исследование технологической адаптации автоматической сварки неповоротных стыков магистральных трубопроводов

Цель работы – определить возможности технологической адаптации автоматической сварки неповоротных стыков магистральных трубопроводов. Автоматизация процесса сварки – перспективное направление сварочного производства. Способ сварки в среде углекислого газа импульсным питанием может быть использован для выполнения неповоротных стыков магистральных трубопроводов. Доказана экономическая эффективность, использования автоматического способа сварки импульсным питанием в среде углекислого газа при строительстве трубопроводов. Эта технология так же позволяет значительно экономить и сокращать время выполнения работ.Purpose - to identify opportunities for technological adaptation of automatic welding of pipelines orbital joints. Automation of the welding process - a promising direction of welding production. Welding process in carbon dioxide pulsed power can be used to perform a non-rotating joints of pipelines. Prove the cost-effectiveness, the use of automatic welding process pulse power in the environment of carbonic gas pipeline construction. This technology also allows significant savings and reduce the time period needed

Алгоритм оценки климато-экологических параметров окружающей среды Евразии

В работе представлен алгоритм климатической кластеризации. Алгоритм позволяет проводить выделения климатических кластеров в различных пространственно-временных масштабах, используя описание температурных сигналов. Характеристики фазы и амплитуды температурных сигналов впервые применены в качестве критериев выделения климатических кластеров. В результате применения алгоритма климатической кластеризации удалось исходное пространство температурных сигналов структурировать в определенное количество климатических кластеров.The paper presents an algorithm for climate clustering. The algorithm allows to allocate clusters of clusters at various space-time scales, using the description of temperature signals. The characteristics of the phase and amplitude of the temperature signals were first applied as criteria for the isolation of climatic clusters. As a result of the application of the climate clustering algorithm, the initial space of temperature signals was structured into a certain number of climatic clusters