Sample records for thermal distribution systems

  1. Thermal Diffusivity Identification of Distributed Parameter Systems to Sea Ice

    Directory of Open Access Journals (Sweden)

    Liqiong Shi


    Full Text Available A method of optimal control is presented as a numerical tool for solving the sea ice heat transfer problem governed by a parabolic partial differential equation. Taken the deviation between the calculated ice temperature and the measurements as the performance criterion, an optimal control model of distributed parameter systems with specific constraints of thermal properties of sea ice was proposed to determine the thermal diffusivity of sea ice. Based on sea ice physical processes, the parameterization of the thermal diffusivity was derived through field data. The simulation results illustrated that the identified parameterization of the thermal diffusivity is reasonably effective in sea ice thermodynamics. The direct relation between the thermal diffusivity of sea ice and ice porosity is physically significant and can considerably reduce the computational errors. The successful application of this method also explained that the optimal control model of distributed parameter systems in conjunction with the engineering background has great potential in dealing with practical problems.

  2. Nonequilibrium Microscopic Distribution of Thermal Current in Particle Systems

    KAUST Repository

    Yukawa, Satoshi


    A nonequilibrium distribution function of microscopic thermal current is studied by a direct numerical simulation in a thermal conducting steady state of particle systems. Two characteristic temperatures of the thermal current are investigated on the basis of the distribution. It is confirmed that the temperature depends on the current direction; Parallel temperature to the heat-flux is higher than antiparallel one. The difference between the parallel temperature and the antiparallel one is proportional to a macroscopic temperature gradient. ©2009 The Physical Society of Japan.

  3. Nonequilibrium Distribution of the Microscopic Thermal Current in Steady Thermal Transport Systems

    KAUST Repository

    Yukawa, Satoshi


    Nonequilibrium distribution of the microscopic thermal current is investigated by direct molecular dynamics simulations. The microscopic thermal current in this study is defined by a flow of kinetic energy carried by a single particle. Asymptotic parallel and antiparallel tails of the nonequilibrium distribution to an average thermal current are identical to ones of equilibrium distribution with different temperatures. These temperatures characterizing the tails are dependent on a characteristic length in which a memory of dynamics is completely erased by several particle collisions. This property of the tails of nonequilibrium distribution is confirmed in other thermal transport systems. In addition, statistical properties of a particle trapped by a harmonic potential in a steady thermal conducting state are also studied. This particle feels a finite force parallel to the average thermal current as a consequence of the skewness of the distribution of the current. This force is interpreted as the microscopic origin of thermophoresis.

  4. Commercial thermal distribution systems, Final report for CIEE/CEC

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Tengfang; Bechu, Olivier; Carrie, Remi; Dickerhoff, Darryl; Fisk, William; Franconi, Ellen; Kristiansen, Oyvind; Levinson, Ronnen; McWilliams, Jennifer; Wang, Duo; Modera, Mark; Webster, Tom; Ring, Erik; Zhang, Qiang; Huizenga, Charlie; Bauman, Fred; Arens, Ed


    According to the California Energy Commission (CEC 1998a), California commercial buildings account for 35% of statewide electricity consumption, and 16% of statewide gas consumption. Space conditioning accounts for roughly 16,000 GWh of electricity and 800 million therms of natural gas annually, and the vast majority of this space conditioning energy passes through thermal distribution systems in these buildings. In addition, 8600 GWh per year is consumed by fans and pumps in commercial buildings, most of which is used to move the thermal energy through these systems. Research work at Lawrence Berkeley National Laboratory (LBNL) has been ongoing over the past five years to investigate the energy efficiency of these thermal distribution systems, and to explore possibilities for improving that energy efficiency. Based upon that work, annual savings estimates of 1 kWh/ft{sup 2} for light commercial buildings, and 1-2 kWh/ft{sup 2} in large commercial buildings have been developed for the particular aspects of thermal distribution system performance being addressed by this project. Those savings estimates, combined with a distribution of the building stock based upon an extensive stock characterization study (Modera et al. 1999a), and technical penetration estimates, translate into statewide saving potentials of 2000 GWh/year and 75 million thermal/year, as well as an electricity peak reduction potential of 0.7 GW. The overall goal of this research program is to provide new technology and application knowledge that will allow the design, construction, and energy services industries to reduce the energy waste associated with thermal distribution systems in California commercial buildings. The specific goals of the LBNL efforts over the past year were: (1) to advance the state of knowledge about system performance and energy losses in commercial-building thermal distribution systems; (2) to evaluate the potential of reducing thermal losses through duct sealing, duct

  5. Temperature Distribution and Thermal Performance of an Aquifer Thermal Energy Storage System (United States)

    Ganguly, Sayantan


    Energy conservation and storage has become very crucial to make use of excess energy during times of future demand. Excess thermal energy can be captured and stored in aquifers and this technique is termed as Aquifer Thermal Energy Storage (ATES). Storing seasonal thermal energy in water by injecting it into subsurface and extracting in time of demand is the principle of an ATES system. Using ATES systems leads to energy savings, reduces the dependency on fossil fuels and thus leads to reduction in greenhouse gas emission. This study numerically models an ATES system to store seasonal thermal energy and evaluates the performance of it. A 3D thermo-hydrogeological numerical model for a confined ATES system is presented in this study. The model includes heat transport processes of advection, conduction and heat loss to confining rock media. The model also takes into account regional groundwater flow in the aquifer, geothermal gradient and anisotropy in the aquifer. Results show that thermal injection into the aquifer results in the generation of a thermal-front which grows in size with time. Premature thermal-breakthrough causes thermal interference in the system when the thermal-front reaches the production well and consequences in the fall of system performance and hence should be avoided. This study models the transient temperature distribution in the aquifer for different flow and geological conditions. This may be effectively used in designing an efficient ATES project by ensuring safety from thermal-breakthrough while catering to the energy demand. Based on the model results a safe well spacing is proposed. The thermal energy discharged by the system is determined and strategy to avoid the premature thermal-breakthrough in critical cases is discussed. The present numerical model is applied to simulate an experimental field study which is found to approximate the field results quite well.

  6. Comparison of indoor air distribution and thermal environment for different combinations of radiant heating systems with mechanical ventilation systems

    DEFF Research Database (Denmark)

    Wu, Xiaozhou; Fang, Lei; Olesen, Bjarne W.


    air distribution and the thermal environment for all combinations of radiant heating systems with mechanical ventilation systems. Therefore, in this article, the indoor air distribution and the thermal environment were comparatively analyzed in a room with floor heating (FH) or ceiling heating (CH...


    Energy Technology Data Exchange (ETDEWEB)



    This is an update of a report (Andrews and Modera 1991) that quantified the amounts of energy that could be saved through better thermal distribution systems in residential and small commercial buildings. Thermal distribution systems are the ductwork, piping, or other means used to transport heat or cooling from the space-conditioning equipment to the conditioned space. This update involves no basic change in methodology relative to the 1991 report, but rather a review of the additional information available in 2003 on the energy-use patterns in residential and small commercial buildings.

  8. A vacuum system for the thermal insulation of the SciFi distribution lines and manifolds

    CERN Document Server

    Joram, Christian


    This note describes some calculations and estimates for the layout, technology choice and performance of a vacuum system which shall ensure thermal insulation of the distribution lines and manifolds of the SiPM cooling system of the LHCb SciFi detector. We estimate the heat losses in concentric corrugated stainless steel pipes which leads to the conclusion that the pipes need to be evacuated to a pressure of about 1·10$^{-4}$ mbar. We then estimate the pumping conductance of the pipes and find that it will dominate over the effective pumping speed of any pump. We therefore conclude that a turbo molecular pump of small nominal pumping speed, which can easily achieve end pressures below 10$^{-5}$ mbar is adequate for this purpose. A preliminary layout of the vacuum system is being discussed at the end of the document.

  9. Thermal conveyance systems

    Energy Technology Data Exchange (ETDEWEB)

    Meador, J.T.


    The purpose of the evaluation is to characterize modern technology for long-distance, large-diameter, underground steam and high-temperature water (HTW) transport systems and for hot-water and chilled-water systems that distribute thermal energy within communities. Data on the status of existing systems have been compiled and compared with recommended design factors for fluid flow to aid in parameter selection for assessing performance in transporting and distributing thermal energy.

  10. Second law optimization of a sensible heat thermal energy storage system with a distributed storage element

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, M.J.


    This numerical study defined the behavior of a sensible heat thermal energy storage system whose physical design and operation had been optimized to minimize the production of thermodynamic irreversibilities. It included the effects of transient conduction within the storage material. A dimensionless set of governing equations was defined for a complete storage-removal cycle that included the effects of entropy generation due to convection and viscous effects in the flowing fluid, two-dimensional transient conduction within the storage material, and to convection due to the discharged hot fluid coming to equilibrium with the environment during the storage period. A computer program was written to solve this equation set and this program was in turn controlled by a sophisticated optimization routine to determine a dimensionless storage time, flow channel half-height, and heat transfer coefficient that resulted in a minimum amount of availability destruction. The results of this analysis showed that entropy generation within the storage material due to transient conduction was a major contributor to the total thermal irreversibilities associated with the operation of a sensible heat thermal energy storage system. For the counterflow configuration and over the range of design variables examined, material entropy generation accounted for between 26% and 60% of the total thermal availability destruction that occurred during a complete storage-removal cycle. It was also shown that the storage material aspect ratio had a significant impact on the optimum design of a storage system. Its influence was second only to the fluid mass velocity.

  11. Thermal stress comparison in modular power converter topologies for smart transformers in the electrical distribution system

    DEFF Research Database (Denmark)

    Andresen, Markus; Ma, Ke; Liserre, Marco


    A Smart Transformer (ST) can cover an important managing role in the future electrical distribution grid. For the moment, the reliability and cost are not competitive with traditional transformers and create a barrier for its application. This work conduct detail designs and analysis...... for a promising modular ST solution, which is composed of Modular Multi-level converter, Quad Active Bridge DC-DC converters, and two-level voltage source converters. The focus is put on the loading conditions and thermal stress of power semiconductor devices in order to discover critical parts of the whole...

  12. A prototype data archive for the PIER 'thermal distribution systems in commercial buildings' project

    Energy Technology Data Exchange (ETDEWEB)

    Diamond, Rick C.; Wray, Craig P.; Smith, Brian V.; Dickerhoff, Darryl J.; Matson, Nance E.; Cox, Skylar A.


    A prototype archive for a selection of building energy data on thermal distribution systems in commercial buildings was developed and pilot tested. While the pilot demonstrated the successful development of the data archive prototype, several questions remain about the usefulness of such an archive. Specifically, questions on the audience, frequency of use, maintenance, and updating of the archive would need to be addressed before this prototype is taken to the next level.

  13. Thermal comfort and indoor air quality in rooms with integrated personalized ventilation and under-floor air distribution systems

    DEFF Research Database (Denmark)

    Li, Ruixin; Sekhar ., S. C.; Melikov, Arsen Krikor


    A comprehensive study comprising physical measurements and human subject experiments was conducted to explore the potential for improving occupants' thermal comfort and indoor air quality (IAQ) using a personalized ventilation (PV) system combined with an under-floor air distribution(UFAD) system....... The integrated PV-UFAD system, when operated at relatively high temperature of the air supplied from the UFAD system, provided comfortable cooling of the facial region, improved inhaled air quality, and decreased the risk of "cold feet," which is often reported in rooms with UFAD alone. This article explores...... with thermal sensation at the face region. The measured inhaled air quality indices (personalized exposure effectiveness and personalized exposure index) were improved by decreasing PV supply air temperature. The perceived inhaled air freshness increased with the decrease of the inhaled air temperature...

  14. Temperature distribution and thermal stress

    Indian Academy of Sciences (India)

    The minimum stress and minimum stress difference are shown in equal double pumping. 4. Conclusion. In the present work, the temperature distribution and thermal stress of the actual double-end-pumped Nd:YVO4 cubic crystal have been discussed. The results show that by considering the input power as a constant, the ...

  15. Distributed systems

    CERN Document Server

    Van Steen, Maarten


    For this third edition of "Distributed Systems," the material has been thoroughly revised and extended, integrating principles and paradigms into nine chapters: 1. Introduction 2. Architectures 3. Processes 4. Communication 5. Naming 6. Coordination 7. Replication 8. Fault tolerance 9. Security A separation has been made between basic material and more specific subjects. The latter have been organized into boxed sections, which may be skipped on first reading. To assist in understanding the more algorithmic parts, example programs in Python have been included. The examples in the book leave out many details for readability, but the complete code is available through the book's Website, hosted at

  16. Thermal comfort and IAQ assessment of under-floor air distribution system integrated with personalized ventilation in hot and humid climate

    DEFF Research Database (Denmark)

    Li, Ruixin; Sekhar, S.C.; Melikov, Arsen Krikor


    The potential for improving occupants' thermal comfort with personalized ventilation (PV) system combined with under-floor air distribution (UFAD) system was explored through human response study. The hypothesis was that cold draught at feet can be reduced when relatively warm air is supplied...

  17. Crossover of the Thermal Escape Problem in Annular Spatially Distributed Systems (United States)

    Fedorov, Kirill G.; Pankratov, Andrey L.


    The computer simulations of fluctuational dynamics of an annular system governed by the sine-Gordon model with a white noise source are performed. It is demonstrated that the mean escape time (MET) of a phase string for an annular structure can be much larger than for a linear one and has a strongly pronounced maximum as a function of system’s length. The location of the MET maximum roughly equals the size of the kink-antikink pair, which leads to evidence of a spatial crossover between two dynamical regimes: when the phase string escapes over the potential barrier as a whole and when the creation of kink-antikink pairs is the main mechanism of the escape process. For large lengths and in the limit of small noise intensity γ, for both MET and inverse concentration of kinks, we observe the same dependence versus the kink energy Ek: ˜exp⁡(2Ek/γ) for the annular structure and ˜exp⁡(Ek/γ) for the linear one.

  18. 3D Temperature Distribution Model Based on Thermal Infrared Image

    Directory of Open Access Journals (Sweden)

    Tong Jia


    Full Text Available This paper aims to study the construction of 3D temperature distribution reconstruction system based on binocular vision technology. Initially, a traditional calibration method cannot be directly used, because the thermal infrared camera is only sensitive to temperature. Therefore, the thermal infrared camera is calibrated separately. Belief propagation algorithm is also investigated and its smooth model is improved in terms of stereo matching to optimize mismatching rate. Finally, the 3D temperature distribution model is built based on the matching of 3D point cloud and 2D thermal infrared information. Experimental results show that the method can accurately construct the 3D temperature distribution model and has strong robustness.

  19. Finite thermal reservoirs and the canonical distribution (United States)

    Griffin, William; Matty, Michael; Swendsen, Robert H.


    The microcanonical ensemble has long been a starting point for the development of thermodynamics from statistical mechanics. However, this approach presents two problems. First, it predicts that the entropy is only defined on a discrete set of energies for finite, quantum systems, while thermodynamics requires the entropy to be a continuous function of the energy. Second, it fails to satisfy the stability condition (ΔS / ΔU classical and quantum systems. Swendsen has recently shown that the source of these problems lies in the microcanonical ensemble itself, which contains only energy eigenstates and excludes their linear combinations. To the contrary, if the system of interest has ever been in thermal contact with another system, it will be described by a probability distribution over many eigenstates that is equivalent to the canonical ensemble for sufficiently large systems. Novotny et al. have recently supported this picture by dynamical numerical calculations for a quantum mechanical model, in which they showed the approach to a canonical distribution for up to 40 quantum spins. By simplifying the problem to calculate only the equilibrium properties, we are able to extend the demonstration to more than a million particles.

  20. Estimating spatially distributed turbulent heat fluxes from high-resolution thermal imagery acquired with a UAV system. (United States)

    Brenner, Claire; Thiem, Christina Elisabeth; Wizemann, Hans-Dieter; Bernhardt, Matthias; Schulz, Karsten


    aerodynamic and radiometric temperature) that depends on the surface-to-air temperature gradient yielded the best agreement with EC measurements. This study showed that the applied UAV system equipped with a dual-camera set-up allows for the acquisition of thermal imagery with high spatial and temporal resolution that illustrates the small-scale heterogeneity of thermal surface properties. The UAV-based thermal imagery therefore provides the means for analysing patterns of LST and other surface properties with a high level of detail that cannot be obtained by traditional remote sensing methods.

  1. Proceedings of the 1992 DOE-industry thermal distribution conference

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, J.W. (ed.)


    The subject of the conference was thermal distribution in small buildings. Thermal distribution systems are the ductwork, piping, or other means used to transport heat or cooling effect from the equipment in which the heat or cooling is produced to the building spaces in which it is used. The small buildings category is defined to include single-family residential and multifamily and commercial buildings with less than 10,000 ft{sup 2} floor area. The 1992 DOE-Industry Thermal Distribution Conference was conceived as the beginning of a process of information transfer between the DOE and the industries having a stake in thermal distribution systems, whereby the DOE can make the industry aware of its thinking and planned directions early enough for changes to be made, and whereby the industries represented can provide this input to the DOE on a timely and informed basis. In accordance with this, the objectives of the Conference were: To present--to a representative group of researchers and industry representative--the current industry thinking and DOE's current directions for research in small-building thermal distribution. To obtain from industry and the research community a critique of the DOE priorities and additional ideas concerning how DOE can best assist the industry in promoting energy conservation in thermal distribution systems.

  2. Proceedings of the 1992 DOE-industry thermal distribution conference

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, J.W. [ed.


    The subject of the conference was thermal distribution in small buildings. Thermal distribution systems are the ductwork, piping, or other means used to transport heat or cooling effect from the equipment in which the heat or cooling is produced to the building spaces in which it is used. The small buildings category is defined to include single-family residential and multifamily and commercial buildings with less than 10,000 ft{sup 2} floor area. The 1992 DOE-Industry Thermal Distribution Conference was conceived as the beginning of a process of information transfer between the DOE and the industries having a stake in thermal distribution systems, whereby the DOE can make the industry aware of its thinking and planned directions early enough for changes to be made, and whereby the industries represented can provide this input to the DOE on a timely and informed basis. In accordance with this, the objectives of the Conference were: To present--to a representative group of researchers and industry representative--the current industry thinking and DOE`s current directions for research in small-building thermal distribution. To obtain from industry and the research community a critique of the DOE priorities and additional ideas concerning how DOE can best assist the industry in promoting energy conservation in thermal distribution systems.


    Augustynowicz, Stanislaw D. (Inventor); Fesmire, James E. (Inventor)


    Thermal insulation systems and with methods of their production. The thermal insulation systems incorporate at least one reflection layer and at least one spacer layer in an alternating pattern. Each spacer layer includes a fill layer and a carrier layer. The fill layer may be separate from the carrier layer, or it may be a part of the carrier layer, i.e., mechanically injected into the carrier layer or chemically formed in the carrier layer. Fill layers contain a powder having a high surface area and low bulk density. Movement of powder within a fill layer is restricted by electrostatic effects with the reflection layer combined with the presence of a carrier layer, or by containing the powder in the carrier layer. The powder in the spacer layer may be compressed from its bulk density. The thermal insulation systems may further contain an outer casing. Thermal insulation systems may further include strips and seams to form a matrix of sections. Such sections serve to limit loss of powder from a fill layer to a single section and reduce heat losses along the reflection layer.

  4. LOKET—a gamma-ray spectroscopy system for in-pool measurements of thermal power distribution in irradiated nuclear fuel (United States)

    Matsson, Ingvar; Grapengiesser, Björn; Andersson, Björn


    An important issue in the operations of nuclear power plants is the independent validation of core physics codes like e.g. Westinghouse PHOENIX-4/POLCA-7. Such codes are used to predict the thermal power distribution down to single node level in the core. In this paper, a dedicated measurement system (LOKET) is described and experimental results are discussed. The system is based on a submergible housing, containing a high-resolution germanium detector, allowing for measurements in-pool. The system can be transported to virtually any nuclear power plant's fuel storage pool for measurements in-pool during outage. The methodology utilises gamma radiation specific for 140La, whose decay is governed by the parent 140Ba, reflecting a weighted average power distribution, representative for the last weeks of operation of the core. Good agreements between measured power distribution and core physics calculations (Ba distribution) have been obtained during a series of experiments at Leibstadt NPP in Switzerland and Cofrentes NPP in Spain (BWRs) for both fuel assemblies and single fuel rods. The system has proven as a very useful tool for the experimental validation of core calculations also for the most complex fuel designs and challenging core configurations. Experimental errors (on the 1- σ level), has been demonstrated below ±2% on nodal level for assembly measurements.

  5. Thermal Management and Thermal Protection Systems (United States)

    Hasnain, Aqib


    During my internship in the Thermal Design Branch (ES3), I contributed to two main projects: i) novel passive thermal management system for future human exploration, ii) AVCOAT undercut thermal analysis. i) As NASA prepares to further expand human and robotic presence in space, it is well known that spacecraft architectures will be challenged with unprecedented thermal environments. Future exploration activities will have the need of thermal management systems that can provide higher reliability, mass and power reduction and increased performance. In an effort to start addressing the current technical gaps the NASA Johnson Space Center Passive Thermal Discipline has engaged in technology development activities. One of these activities was done through an in-house Passive Thermal Management System (PTMS) design for a lunar lander. The proposed PTMS, functional in both microgravity and gravity environments, consists of three main components: a heat spreader, a novel hybrid wick Variable Conductance Heat Pipe (VCHP), and a radiator. The aim of this PTMS is to keep electronics on a vehicle within their temperature limits (0 and 50 C for the current design) during all mission phases including multiple lunar day/night cycles. The VCHP was tested to verify its thermal performance. I created a thermal math model using Thermal Desktop (TD) and analyzed it to predict the PTMS performance. After testing, the test data provided a means to correlate the thermal math model. This correlation took into account conduction and convection heat transfer, representing the actual benchtop test. Since this PTMS is proposed for space missions, a vacuum test will be taking place to provide confidence that the system is functional in space environments. Therefore, the model was modified to include a vacuum chamber with a liquid nitrogen shroud while taking into account conduction and radiation heat transfer. Infrared Lamps were modelled and introduced into the model to simulate the sun


    Energy Technology Data Exchange (ETDEWEB)



    Use of condensing boilers in residential heating systems offers the potential for significant improvements in efficiency. For these to operate in a condensing mode the return water temperature needs to be about 10 degrees below the saturation temperature for the flue gas water vapor. This saturation temperature depends on fuel type and excess air and ranges from about 110 F to 135 F. Conventional baseboard hydronic distribution systems are most common and these are designed for water temperatures in the 180 F range, well above the saturation temperature. Operating strategies which may allow these systems to operate in a condensing mode have been considered in the past. In this study an approach to achieving this for a significant part of the heating season has been tested in an instrumented home. The approach involves use of an outdoor reset control which reduces the temperature of the water circulating in the hydronic loop when the outdoor temperature is higher than the design point for the region. Results showed that this strategy allows the boiler to operate in the condensing region for 80% of the winter heating season with oil, 90% with propane, and 95% with gas, based on cumulative degree days. The heating system as tested combines space heating and domestic hot water loads using an indirect, 40 gallon tank with an internal heat exchanger. Tests conducted during the summer months showed that the return water temperature from the domestic hot water tank heat exchanger is always below a temperature which will provide condensing operation of the boiler. In the field tests both the condensing boiler and the conventional, non-condensing boiler were in the test home and each was operated periodically to provide a direct performance comparison.

  7. Drinking Water Distribution Systems (United States)

    Learn about an overview of drinking water distribution systems, the factors that degrade water quality in the distribution system, assessments of risk, future research about these risks, and how to reduce cross-connection control risk.

  8. The Numerical Modeling of Thermal Stress Distribution in Thermal Barrier Coatings

    Directory of Open Access Journals (Sweden)

    Jasik A.


    Full Text Available The paper presents the results of numerical calculations of temperature and thermal stress distribution in thermal barrier coatings deposited by thermal spraying process on the nickel based superalloy. An assumption was made to apply conventional zirconium oxide modified with yttrium oxide (8YSZ and apply pyrochlore type material with formula La2Zr2O7. The bond coat was made of NiCoCrAlY. Analysis of the distribution of temperature and stresses in ceramic coatings of different thicknesses was performed in the function of bond-coat thickness and the type of ceramic insulation layer. It was revealed that the thickness of NiCrAlY bond-coat has not significant influence on the stress distribution, but there is relatively strong effect on temperature level. The most important factor influenced on stress distribution in TBC system is related with type and properties of ceramic insulation layer.

  9. Solar thermal power system (United States)

    Bennett, Charles L.


    A solar thermal power generator includes an inclined elongated boiler tube positioned in the focus of a solar concentrator for generating steam from water. The boiler tube is connected at one end to receive water from a pressure vessel as well as connected at an opposite end to return steam back to the vessel in a fluidic circuit arrangement that stores energy in the form of heated water in the pressure vessel. An expander, condenser, and reservoir are also connected in series to respectively produce work using the steam passed either directly (above a water line in the vessel) or indirectly (below a water line in the vessel) through the pressure vessel, condense the expanded steam, and collect the condensed water. The reservoir also supplies the collected water back to the pressure vessel at the end of a diurnal cycle when the vessel is sufficiently depressurized, so that the system is reset to repeat the cycle the following day. The circuital arrangement of the boiler tube and the pressure vessel operates to dampen flow instabilities in the boiler tube, damp out the effects of solar transients, and provide thermal energy storage which enables time shifting of power generation to better align with the higher demand for energy during peak energy usage periods.

  10. Lighting system with heat distribution face plate (United States)

    Arik, Mehmet; Weaver, Stanton Earl; Stecher, Thomas Elliot; Kuenzler, Glenn Howard; Wolfe, Jr., Charles Franklin; Li, Ri


    Lighting systems having a light source and a thermal management system are provided. The thermal management system includes synthetic jet devices, a heat sink and a heat distribution face plate. The synthetic jet devices are arranged in parallel to one and other and are configured to actively cool the lighting system. The heat distribution face plate is configured to radially transfer heat from the light source into the ambient air.

  11. Smart Distribution Systems

    Directory of Open Access Journals (Sweden)

    Yazhou Jiang


    Full Text Available The increasing importance of system reliability and resilience is changing the way distribution systems are planned and operated. To achieve a distribution system self-healing against power outages, emerging technologies and devices, such as remote-controlled switches (RCSs and smart meters, are being deployed. The higher level of automation is transforming traditional distribution systems into the smart distribution systems (SDSs of the future. The availability of data and remote control capability in SDSs provides distribution operators with an opportunity to optimize system operation and control. In this paper, the development of SDSs and resulting benefits of enhanced system capabilities are discussed. A comprehensive survey is conducted on the state-of-the-art applications of RCSs and smart meters in SDSs. Specifically, a new method, called Temporal Causal Diagram (TCD, is used to incorporate outage notifications from smart meters for enhanced outage management. To fully utilize the fast operation of RCSs, the spanning tree search algorithm is used to develop service restoration strategies. Optimal placement of RCSs and the resulting enhancement of system reliability are discussed. Distribution system resilience with respect to extreme events is presented. Test cases are used to demonstrate the benefit of SDSs. Active management of distributed generators (DGs is introduced. Future research in a smart distribution environment is proposed.

  12. Thermal analysis of underground power cable system (United States)

    Rerak, Monika; Ocłoń, Paweł


    The paper presents the application of Finite Element Method in thermal analysis of underground power cable system. The computations were performed for power cables buried in-line in the ground at a depth of 2 meters. The developed mathematical model allows determining the two-dimensional temperature distribution in the soil, thermal backfill and power cables. The simulations studied the effect of soil and cable backfill thermal conductivity on the maximum temperature of the cable conductor. Also, the effect of cable diameter on the temperature of cable core was studied. Numerical analyses were performed based on a program written in MATLAB.

  13. Electric distribution systems

    CERN Document Server

    Sallam, A A


    "Electricity distribution is the penultimate stage in the delivery of electricity to end users. The only book that deals with the key topics of interest to distribution system engineers, Electric Distribution Systems presents a comprehensive treatment of the subject with an emphasis on both the practical and academic points of view. Reviewing traditional and cutting-edge topics, the text is useful to practicing engineers working with utility companies and industry, undergraduate graduate and students, and faculty members who wish to increase their skills in distribution system automation and monitoring."--

  14. Distributed Operating Systems

    NARCIS (Netherlands)

    Tanenbaum, A.S.; van Renesse, R.


    Distributed operating systems have many aspects in common with centralized ones, but they also differ in certain ways. This paper is intended as an introduction to distributed operating systems, and especially to current university research about them. After a discussion of what constitutes a

  15. Distributed Operating Systems

    NARCIS (Netherlands)

    Mullender, Sape J.


    In the past five years, distributed operating systems research has gone through a consolidation phase. On a large number of design issues there is now considerable consensus between different research groups. In this paper, an overview of recent research in distributed systems is given. In turn, the

  16. Cooling water distribution system (United States)

    Orr, Richard


    A passive containment cooling system for a nuclear reactor containment vessel. Disclosed is a cooling water distribution system for introducing cooling water by gravity uniformly over the outer surface of a steel containment vessel using an interconnected series of radial guide elements, a plurality of circumferential collector elements and collector boxes to collect and feed the cooling water into distribution channels extending along the curved surface of the steel containment vessel. The cooling water is uniformly distributed over the curved surface by a plurality of weirs in the distribution channels.

  17. Thermal environmental case study of an existing underfloor air distribution (UFAD) system in a high-rise building in the tropics (United States)

    Ya, Y. H.; Poh, K. S.


    The performance of an existing underfloor air distribution (UFAD) system in a renowned high-rise office tower in Malaysia was studied to identify the root cause issues behind the poor indoor air quality. Occupants are the best thermal sensor. The building was detected with the sick building syndrome (SBS) that causes runny noses, flu-like symptoms, irritated skin, and etc. Long period of exposure to indoor air pollutants may increase the occupant's health risk. The parameters such as the space temperature, relative humidity, air movement, air change, fresh air flow rate, chilled water supply and return are evaluated at three stories that consist of five open offices. A full traverse study was carried out at one of the fresh air duct. A simplified duct flow measurement method using pitot-tubes was developed. The results showed that the diffusers were not effective in creating the swirl effect to the space. Internal heat gain from human and office electrical equipment were not drawn out effectively. Besides, relative humidity has exceeded the recommended level. These issues were caused by the poor maintenance of the building. The energy efficiency strategy of the UFAD system comes from the higher supply air temperature. It may leads to insufficient cooling load for the latent heat gained under improper system performance. Special care and considerations in design, construction and maintenance are needed to ensure the indoor air quality to be maintained. Several improvements were recommended to tackle the existing indoor air quality issues. Solar system was studied as one of the innovative method for retrofitting.

  18. Thermal transport in fractal systems

    DEFF Research Database (Denmark)

    Kjems, Jørgen


    Recent experiments on the thermal transport in systems with partial fractal geometry, silica aerogels, are reviewed. The individual contributions from phonons, fractons and particle modes, respectively, have been identified and can be described by quantitative models consistent with heat capacity...

  19. Ablative Thermal Protection System Fundamentals (United States)

    Beck, Robin A. S.


    This is the presentation for a short course on the fundamentals of ablative thermal protection systems. It covers the definition of ablation, description of ablative materials, how they work, how to analyze them and how to model them.

  20. Lighting system with thermal management system (United States)

    Arik, Mehmet; Weaver, Stanton; Stecher, Thomas; Seeley, Charles; Kuenzler, Glenn; Wolfe, Jr., Charles; Utturkar, Yogen; Sharma, Rajdeep; Prabhakaran, Satish; Icoz, Tunc


    Lighting systems having unique configurations are provided. For instance, the lighting system may include a light source, a thermal management system and driver electronics, each contained within a housing structure. The light source is configured to provide illumination visible through an opening in the housing structure. The thermal management system is configured to provide an air flow, such as a unidirectional air flow, through the housing structure in order to cool the light source. The driver electronics are configured to provide power to each of the light source and the thermal management system.

  1. Distribution System White Papers (United States)

    EPA worked with stakeholders and developed a series of white papers on distribution system issues ranked of potentially significant public health concern (see list below) to serve as background material for EPA, expert and stakeholder discussions.

  2. Distribution system simulator (United States)

    Bahrami, K. A.; Kirkham, H.; Rahman, S.


    In a series of tests performed under the Department of Energy auspices, power line carrier propagation was observed to be anomalous under certain circumstances. To investigate the cause, a distribution system simulator was constructed. The simulator was a physical simulator that accurately represented the distribution system from below power frequency to above 50 kHz. Effects such as phase-to-phase coupling and skin effect were modeled. Construction details of the simulator, and experimental results from its use are presented.

  3. A distribution management system

    Energy Technology Data Exchange (ETDEWEB)

    Verho, P.; Jaerventausta, P.; Kaerenlampi, M.; Paulasaari, H. [Tampere Univ. of Technology (Finland); Partanen, J. [Lappeenranta Univ. of Technology (Finland)


    The development of new distribution automation applications is considerably wide nowadays. One of the most interesting areas is the development of a distribution management system (DMS) as an expansion of the traditional SCADA system. At the power transmission level such a system is called an energy management system (EMS). The idea of these expansions is to provide supporting tools for control center operators in system analysis and operation planning. The needed data for new applications is mainly available in some existing systems. Thus the computer systems of utilities must be integrated. The main data source for the new applications in the control center are the AM/FM/GIS (i.e. the network database system), the SCADA, and the customer information system (CIS). The new functions can be embedded in some existing computer system. This means a strong dependency on the vendor of the existing system. An alternative strategy is to develop an independent system which is integrated with other computer systems using well-defined interfaces. The latter approach makes it possible to use the new applications in various computer environments, having only a weak dependency on the vendors of the other systems. In the research project this alternative is preferred and used in developing an independent distribution management system

  4. A distribution management system

    Energy Technology Data Exchange (ETDEWEB)

    Jaerventausta, P.; Verho, P.; Kaerenlampi, M.; Pitkaenen, M. [Tampere Univ. of Technology (Finland); Partanen, J. [Lappeenranta Univ. of Technology (Finland)


    The development of new distribution automation applications is considerably wide nowadays. One of the most interesting areas is the development of a distribution management system (DMS) as an expansion to the traditional SCADA system. At the power transmission level such a system is called an energy management system (EMS). The idea of these expansions is to provide supporting tools for control center operators in system analysis and operation planning. Nowadays the SCADA is the main computer system (and often the only) in the control center. However, the information displayed by the SCADA is often inadequate, and several tasks cannot be solved by a conventional SCADA system. A need for new computer applications in control center arises from the insufficiency of the SCADA and some other trends. The latter means that the overall importance of the distribution networks is increasing. The slowing down of load-growth has often made network reinforcements unprofitable. Thus the existing network must be operated more efficiently. At the same time larger distribution areas are for economical reasons being monitored at one control center and the size of the operation staff is decreasing. The quality of supply requirements are also becoming stricter. The needed data for new applications is mainly available in some existing systems. Thus the computer systems of utilities must be integrated. The main data source for the new applications in the control center are the AM/FM/GIS (i.e. the network database system), the SCADA, and the customer information system (CIS). The new functions can be embedded in some existing computer system. This means a strong dependency on the vendor of the existing system. An alternative strategy is to develop an independent system which is integrated with other computer systems using well-defined interfaces. The latter approach makes it possible to use the new applications in various computer environments, having only a weak dependency on the

  5. Protection of Distribution Systems with Distributed Generation


    Vassbotten, Kristian


    In recent years the amount of distributed generation(DG) in distribution systems have increased. This poses problems for the traditional protection scheme, with non-directional over-current relays and fuses. When DG is introduced the load flow in distribution systems are often reversed; there is a surplus of power on the radial. Present thesis seeks to determine the most beneficial protection scheme to use in distribution systems with DG. To investigate the impact of different relays and...

  6. The measurements of thermal neutron flux distribution in a paraffin ...

    Indian Academy of Sciences (India)

    The term `thermal flux' implies a Maxwellian distribution of velocity and energy corresponding to the most probable velocity of 2200 ms-1 at 293.4 K. In order to measure the thermal neutron flux density, the foil activation method was used. Thermal neutron flux determination in paraffin phantom by counting the emitted rays of ...

  7. Drainback solar thermal systems

    DEFF Research Database (Denmark)

    Botpaev, R.; Louvet, Y.; Perers, Bengt


    Although solar drainback systems have been used for a long time, they are still generating questions regarding smooth functioning. This paper summarises publications on drainback systems and compiles the current knowledge, experiences, and ideas on the technology. The collective research exhibits...

  8. Drainback solar thermal systems

    DEFF Research Database (Denmark)

    Botpaev, R.; Louvet, Y.; Perers, Bengt


    Although solar drainback systems have been used for a long time, they are still generating questions regarding smooth functioning. This paper summarises publications on drainback systems and compiles the current knowledge, experiences, and ideas on the technology. The collective research exhibits...... of this technology has been developed, with a brief description of each hydraulic typology. The operating modes have been split into three stages: filling, operation, and draining, which have been studied separately. A difference in the minimal filling velocities for a siphon development in the solar loop has been...

  9. Making Distributed Systems Palatable

    NARCIS (Netherlands)

    Tanenbaum, A.S.; van Renesse, R.


    Designing and implementing a distributed system is easy compared to the task of convincing people to use it. In a university Computer Science Dept., people generally use UNIX and are not at all interested in moving to a different environment, no matter how wonderful it may be. In this paper we

  10. Managing Distributed Knowledge Systems

    DEFF Research Database (Denmark)

    Sørensen, Brian Vejrum; Gelbuda, Modestas


    . This paper contributes to the research on organizations as distributed knowledge systems by addressing two weaknesses of the social practice literature. Firstly, it downplays the importance of formal structure and organizational design and intervention efforts by key organizational members. Secondly, it does...

  11. Distributed Systems 3/e

    NARCIS (Netherlands)

    Tanenbaum, A.S.; van Steen, M.R.


    For this third edition of "Distributed Systems," the material has been thoroughly revised and extended, integrating principles and paradigms into nine chapters: 1. Introduction 2. Architectures 3. Processes 4. Communication 5. Naming 6. Coordination 7. Replication 8. Fault tolerance 9. Security A

  12. The Signal Distribution System

    CERN Document Server

    Belohrad, D; CERN. Geneva. AB Department


    For the purpose of LHC signal observation and high frequency signal distribution, the Signal Distribution System (SDS) was built. The SDS can contain up to 5 switching elements, where each element allows the user to switch between one of the maximum 8 bi-directional signals. The coaxial relays are used to switch the signals. Depending of the coaxial relay type used, the transfer bandwidth can go up to 18GHz. The SDS is controllable via TCP/IP, parallel port, or locally by rotary switch.

  13. Distributed Optimization System (United States)

    Hurtado, John E.; Dohrmann, Clark R.; Robinett, III, Rush D.


    A search system and method for controlling multiple agents to optimize an objective using distributed sensing and cooperative control. The search agent can be one or more physical agents, such as a robot, and can be software agents for searching cyberspace. The objective can be: chemical sources, temperature sources, radiation sources, light sources, evaders, trespassers, explosive sources, time dependent sources, time independent sources, function surfaces, maximization points, minimization points, and optimal control of a system such as a communication system, an economy, a crane, and a multi-processor computer.

  14. Thermal animal detection system (TADS)

    Energy Technology Data Exchange (ETDEWEB)

    Desholm, M.


    This report presents data from equipment tests and software development for the Thermal Animal Detection System (TADS) development project: 'Development of a method for estimating collision frequency between migrating birds and offshore wind turbines'. The technical tests were performed to investigate the performance of remote controlling, video file compression tool and physical stress of the thermal camera when operating outdoors and under the real time vibration conditions at a 2 MW turbine. Furthermore, experimental tests on birds were performed to describe the decreasing detectability with distance on free flying birds, the performance of the thermal camera during poor visibility, and finally, the performance of the thermal sensor software developed for securing high -quality data. In general, it can be concluded that the thermal camera and its related hardware and software, the TADS, are capable of recording migrating birds approaching the rotating blades of a turbine, even under conditions with poor visibility. If the TADS is used in a vertical viewing scenario it would comply with the requirements for a setup used for estimating the avian collision frequency at offshore wind turbines. (au)

  15. Distributed Data Management and Distributed File Systems

    CERN Document Server

    Girone, Maria


    The LHC program has been successful in part due to the globally distributed computing resources used for collecting, serving, processing, and analyzing the large LHC datasets. The introduction of distributed computing early in the LHC program spawned the development of new technologies and techniques to synchronize information and data between physically separated computing centers. Two of the most challenges services are the distributed file systems and the distributed data management systems. In this paper I will discuss how we have evolved from local site services to more globally independent services in the areas of distributed file systems and data management and how these capabilities may continue to evolve into the future. I will address the design choices, the motivations, and the future evolution of the computing systems used for High Energy Physics.

  16. Distributed Data Management and Distributed File Systems (United States)

    Girone, Maria


    The LHC program has been successful in part due to the globally distributed computing resources used for collecting, serving, processing, and analyzing the large LHC datasets. The introduction of distributed computing early in the LHC program spawned the development of new technologies and techniques to synchronize information and data between physically separated computing centers. Two of the most challenges services are the distributed file systems and the distributed data management systems. In this paper I will discuss how we have evolved from local site services to more globally independent services in the areas of distributed file systems and data management and how these capabilities may continue to evolve into the future. I will address the design choices, the motivations, and the future evolution of the computing systems used for High Energy Physics.

  17. Components of solar thermal systems


    Mendes, J. Farinha; Carvalho, M.J.; Schossig, Peter


    The heat production sub-system is the part of the overall system which provides heat to a thermally driven air-conditioning system. With regards to the solar-driven equipment, the solar collector is the main component of the sub-system. A brief review on the present state-of-the-art with respect to performance characteristics and available certification schemes of solar collectors is given in the following chapter. Besides the solar collector field, the storage unit and the back-up heat sourc...

  18. Distributed Systems Technology Survey. (United States)


    S-106 WMh IN7 Distributed Systems Technology Survey Eric C. Cooper Aooousion For DTUC TAIB 1hanUMMOMOd 03 .Tustrifitles AVailability Codes T I F.E .CT...should be connected redundantly, so that there we several paths or routs between any two nodes. In message, swiching , Individuial messages we routed...ADDRESS (City. State and ZIP Cod) -7b. ADDRESS (City. State and ZIP Code ) CARENGIE-HELLON UNIVERSITY ESD/XRSI PITTSBURGH, PA 15213 HANSCOM AIR FORCE

  19. Distributed Deliberative Recommender Systems (United States)

    Recio-García, Juan A.; Díaz-Agudo, Belén; González-Sanz, Sergio; Sanchez, Lara Quijano

    Case-Based Reasoning (CBR) is one of most successful applied AI technologies of recent years. Although many CBR systems reason locally on a previous experience base to solve new problems, in this paper we focus on distributed retrieval processes working on a network of collaborating CBR systems. In such systems, each node in a network of CBR agents collaborates, arguments and counterarguments its local results with other nodes to improve the performance of the system's global response. We describe D2ISCO: a framework to design and implement deliberative and collaborative CBR systems that is integrated as a part of jcolibritwo an established framework in the CBR community. We apply D2ISCO to one particular simplified type of CBR systems: recommender systems. We perform a first case study for a collaborative music recommender system and present the results of an experiment of the accuracy of the system results using a fuzzy version of the argumentation system AMAL and a network topology based on a social network. Besides individual recommendation we also discuss how D2ISCO can be used to improve recommendations to groups and we present a second case of study based on the movie recommendation domain with heterogeneous groups according to the group personality composition and a group topology based on a social network.

  20. Distributed System Design Checklist (United States)

    Hall, Brendan; Driscoll, Kevin


    This report describes a design checklist targeted to fault-tolerant distributed electronic systems. Many of the questions and discussions in this checklist may be generally applicable to the development of any safety-critical system. However, the primary focus of this report covers the issues relating to distributed electronic system design. The questions that comprise this design checklist were created with the intent to stimulate system designers' thought processes in a way that hopefully helps them to establish a broader perspective from which they can assess the system's dependability and fault-tolerance mechanisms. While best effort was expended to make this checklist as comprehensive as possible, it is not (and cannot be) complete. Instead, we expect that this list of questions and the associated rationale for the questions will continue to evolve as lessons are learned and further knowledge is established. In this regard, it is our intent to post the questions of this checklist on a suitable public web-forum, such as the NASA DASHLink AFCS repository. From there, we hope that it can be updated, extended, and maintained after our initial research has been completed.

  1. Methods of forming thermal management systems and thermal management methods (United States)

    Gering, Kevin L.; Haefner, Daryl R.


    A thermal management system for a vehicle includes a heat exchanger having a thermal energy storage material provided therein, a first coolant loop thermally coupled to an electrochemical storage device located within the first coolant loop and to the heat exchanger, and a second coolant loop thermally coupled to the heat exchanger. The first and second coolant loops are configured to carry distinct thermal energy transfer media. The thermal management system also includes an interface configured to facilitate transfer of heat generated by an internal combustion engine to the heat exchanger via the second coolant loop in order to selectively deliver the heat to the electrochemical storage device. Thermal management methods are also provided.

  2. Prevalence and distribution of Legionella spp in potable water systems in Germany, risk factors associated with contamination, and effectiveness of thermal disinfection. (United States)

    Kruse, Eva-Brigitta; Wehner, Arno; Wisplinghoff, Hilmar


    Worldwide, Legionella spp are a common cause of community-acquired pneumonia. Potable water systems are a main reservoir; however, exposure in the community is unknown. Water samples from 718 buildings in Germany were collected. Possible risk factors were prospectively recorded. All samples were tested for Legionella spp using cultural microbiologic methods. Samples were assigned to 1 of 5 levels of contamination. Statistical analysis was performed to determine the influence of risk factors for contamination and, in a subgroup of buildings, for unsuccessful thermal disinfection. In total, 4,482 water samples from 718 different water supply systems were analyzed. In 233 buildings (32.7%), Legionella spp were identified, 148 (63.5%) of which had a medium or higher level of contamination. The most common species was Legionella pneumophila (94%). Contamination was strongly associated with temperature in the circulation, but not with the size of the building, time of the year, or transport time to the laboratory. Thermal disinfection was successful in fewer than half of the buildings. There is relevant exposure to Legionella spp in the community. Water systems are not always up to current technical standards. Although microbiological risk assessment remains a challenge, there is a case for monitoring for Legionella spp outside of hospitals. Copyright © 2016 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  3. Distributed road assessment system (United States)

    Beer, N. Reginald; Paglieroni, David W


    A system that detects damage on or below the surface of a paved structure or pavement is provided. A distributed road assessment system includes road assessment pods and a road assessment server. Each road assessment pod includes a ground-penetrating radar antenna array and a detection system that detects road damage from the return signals as the vehicle on which the pod is mounted travels down a road. Each road assessment pod transmits to the road assessment server occurrence information describing each occurrence of road damage that is newly detected on a current scan of a road. The road assessment server maintains a road damage database of occurrence information describing the previously detected occurrences of road damage. After the road assessment server receives occurrence information for newly detected occurrences of road damage for a portion of a road, the road assessment server determines which newly detected occurrences correspond to which previously detected occurrences of road damage.

  4. Communication Facilities for Distributed Systems

    Directory of Open Access Journals (Sweden)

    V. Barladeanu


    Full Text Available The design of physical networks and communication protocols in Distributed Systems can have a direct impact on system efficiency and reliability. This paper tries to identify efficient mechanisms and paradigms for communication in distributed systems.

  5. Optimizing queries in distributed systems

    Directory of Open Access Journals (Sweden)

    Ion LUNGU


    Full Text Available This research presents the main elements of query optimizations in distributed systems. First, data architecture according with system level architecture in a distributed environment is presented. Then the architecture of a distributed database management system (DDBMS is described on conceptual level followed by the presentation of the distributed query execution steps on these information systems. The research ends with presentation of some aspects of distributed database query optimization and strategies used for that.


    Directory of Open Access Journals (Sweden)

    T. A. Ismailov


    Full Text Available Aim. The article deals with the problem of constructing the power supply devices in the composition of the ship's secondary power systems based on standardized blocks and securing their thermal regime.Methods. It is stated that with the advent of modern power electronics multifunctional components the secondary power supply developers got possibilities to improve the quality of secondary power supply and to upgrade the existing systems.Results. The advantages of unified power units, having a function of parallel operation are revealed. Heat transfer processes in a vertical channel with free convection, and the calculation of the minimum width of the channel, which provides efficient heat removal have been analyzed.Conclusion.A model is proposed for determining the minimum distance between the blocks without deterioration of heat transfer in the channel formed by the walls of adjacent blocks.

  7. Statistical distribution of thermal vacancies close to the melting point

    Energy Technology Data Exchange (ETDEWEB)

    José Pozo, María, E-mail: [Grupo de Nanomateriales, Departamento de Física, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago (Chile); Davis, Sergio, E-mail: [Grupo de Nanomateriales, Departamento de Física, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago (Chile); Peralta, Joaquín, E-mail: [Departamento de Ciencias Físicas, Facultad de Ciencias Exactas, Universidad Andrés Bello, Santiago (Chile)


    A detailed description of the statistical distribution of thermal vacancies in an homogeneous crystal near its melting point is presented, using the embedded atom model for copper as an example. As the temperature increase, the average number of thermal vacancies generated by atoms migrating to neighboring sites increases according to Arrhenius’ law. We present for the first time a model for the statistical distribution of thermal vacancies, which according to our atomistic computer simulations follow a Gamma distribution. All the simulations are carried out by classical molecular dynamics and the recognition of vacancies is achieved via a recently developed algorithm. Our results could be useful in the further development of a theory explaining the mechanism of homogeneous melting, which seems to be mediated by the accumulation of thermal vacancies near the melting point.

  8. Contracts in distributed systems

    Directory of Open Access Journals (Sweden)

    Massimo Bartoletti


    Full Text Available We present a parametric calculus for contract-based computing in distributed systems. By abstracting from the actual contract language, our calculus generalises both the contracts-as-processes and contracts-as-formulae paradigms. The calculus features primitives for advertising contracts, for reaching agreements, and for querying the fulfilment of contracts. Coordination among principals happens via multi-party sessions, which are created once agreements are reached. We present two instances of our calculus, by modelling contracts as (i processes in a variant of CCS, and (ii as formulae in a logic. With the help of a few examples, we discuss the primitives of our calculus, as well as some possible variants.

  9. Advanced materials for thermal protection system (United States)

    Heng, Sangvavann; Sherman, Andrew J.


    Reticulated open-cell ceramic foams (both vitreous carbon and silicon carbide) and ceramic composites (SiC-based, both monolithic and fiber-reinforced) were evaluated as candidate materials for use in a heat shield sandwich panel design as an advanced thermal protection system (TPS) for unmanned single-use hypersonic reentry vehicles. These materials were fabricated by chemical vapor deposition/infiltration (CVD/CVI) and evaluated extensively for their mechanical, thermal, and erosion/ablation performance. In the TPS, the ceramic foams were used as a structural core providing thermal insulation and mechanical load distribution, while the ceramic composites were used as facesheets providing resistance to aerodynamic, shear, and erosive forces. Tensile, compressive, and shear strength, elastic and shear modulus, fracture toughness, Poisson's ratio, and thermal conductivity were measured for the ceramic foams, while arcjet testing was conducted on the ceramic composites at heat flux levels up to 5.90 MW/m2 (520 Btu/ft2ṡsec). Two prototype test articles were fabricated and subjected to arcjet testing at heat flux levels of 1.70-3.40 MW/m2 (150-300 Btu/ft2ṡsec) under simulated reentry trajectories.

  10. Security considerations in distributed systems


    Rhead, Donovan Ross


    Approved for public release; distribution is unlimited This thesis investigates computer security considerations in distributed systems. In particular, it concentrates on assisting managers to gain an appreciation for what distributed systems are, and what are the inherent security issues in these systems. A survey of the literature on computer security was conducted to identify those issues unique to distributed systems. Although many controls are discussed, management must design ...

  11. Transient thermal analysis of a titanium multiwall thermal protection system (United States)

    Blosser, M. L.


    The application of the SPAR thermal analyzer to the thermal analysis of a thermal protection system concept is discussed. The titanium multiwall thermal protection system concept consists of alternate flat and dimpled sheets which are joined together at the crests of the dimples and formed into 30 cm by 30 cm (12 in. by 12 in.) tiles. The tiles are mechanically attached to the structure. The complex tile geometry complicates thermal analysis. Three modes of heat transfer were considered: conduction through the gas inside the tile, conduction through the metal, and radiation between the various layers. The voids between the dimpled and flat sheets were designed to be small enough so that natural convection is insignificant (e.g., Grashof number 1000). A two step approach was used in the thermal analysis of the multiwall thermal protection system. First, an effective normal (through-the-thickness) thermal conductivity was obtained from a steady state analysis using a detailed SPAR finite element model of a small symmetric section of the multiwall tile. This effective conductivity was then used in simple one dimensional finite element models for preliminary analysis of several transient heat transfer problems.

  12. Degenerate optimal paths in thermally isolated systems (United States)

    Acconcia, Thiago V.; Bonança, Marcus V. S.


    We present an analysis of the work performed on a system of interest that is kept thermally isolated during the switching of a control parameter. We show that there exists, for a certain class of systems, a finite-time family of switching protocols for which the work is equal to the quasistatic value. These optimal paths are obtained within linear response for systems initially prepared in a canonical distribution. According to our approach, such protocols are composed of a linear part plus a function which is odd with respect to time reversal. For systems with one degree of freedom, we claim that these optimal paths may also lead to the conservation of the corresponding adiabatic invariant. This points to an interesting connection between work and the conservation of the volume enclosed by the energy shell. To illustrate our findings, we solve analytically the harmonic oscillator and present numerical results for certain anharmonic examples.

  13. Investigation on nanoparticle distribution for thermal ablation of a tumour subjected to nanoparticle assisted thermal therapy. (United States)

    Soni, Sanjeev; Tyagi, Himanshu; Taylor, Robert A; Kumar, Amod


    This study investigates the effect of the distribution of nanoparticles delivered to a skin tumour for the thermal ablation conditions attained during thermal therapy. Ultimate aim is to define a distribution of nanoparticles as well as a combination of other therapeutic parameters to attain thermal ablation temperatures (50-60 °C) within whole of the tumour region. Three different cases of nanoparticle distributions are analysed under controlled conditions for all other parameters viz. irradiation intensity and duration, and volume fraction of nanoparticles. Results show that distribution of nanoparticles into only the periphery of tumour resulted in desired thermal ablation temperature in whole of tumour. For the tumour size considered in this study, an irradiation intensity of 1.25 W/cm(2) for duration of 300 s and a nanoparticle volume fraction of 0.001% was optimal to attain a temperature of ≥53 °C within the whole tumour region. It is concluded that distribution of nanoparticles in peripheral region of tumour, along with a controlled combination of other parameters, seems favourable and provides a promising pathway for thermal ablation of a tumour subjected to nanoparticle assisted thermal therapy. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Distribution System Pricing with Distributed Energy Resources

    Energy Technology Data Exchange (ETDEWEB)

    Hledik, Ryan [The Brattle Group, Cambridge, MA (United States); Lazar, Jim [The Regulatory Assistance Project, Montpelier, VT (United States); Schwartz, Lisa [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)


    Technological changes in the electric utility industry bring tremendous opportunities and significant challenges. Customers are installing clean sources of on-site generation such as rooftop solar photovoltaic (PV) systems. At the same time, smart appliances and control systems that can communicate with the grid are entering the retail market. Among the opportunities these changes create are a cleaner and more diverse power system, the ability to improve system reliability and system resilience, and the potential for lower total costs. Challenges include integrating these new resources in a way that maintains system reliability, provides an equitable sharing of system costs, and avoids unbalanced impacts on different groups of customers, including those who install distributed energy resources (DERs) and low-income households who may be the least able to afford the transition.

  15. Distributed security in closed distributed systems

    DEFF Research Database (Denmark)

    Hernandez, Alejandro Mario

    in their design. There should always exist techniques for ensuring that the required security properties are met. This has been thoroughly investigated through the years, and many varied methodologies have come through. In the case of distributed systems, there are even harder issues to deal with. Many approaches...... systems. We achieve the goal of showing how this can be done, though we restrict ourselves to closed systems and with a limited set of enforceable security policies. In this setting, our approach proves to be efficient. Finally, we achieve all this by bringing together several fields of Computer Science...

  16. RBAC Administration in Distributed Systems

    NARCIS (Netherlands)

    Dekker, M.A.C.; Crampton, J.; Etalle, Sandro


    Despite a large body of literature on the administration of RBAC policies in centralized systems, the problem of the administration of a distributed system has hardly been addressed. We present a formal system for modelling a distributed RBAC system and its administration. We define two basic

  17. Thermal protection system ablation sensor (United States)

    Gorbunov, Sergey (Inventor); Martinez, Edward R. (Inventor); Scott, James B. (Inventor); Oishi, Tomomi (Inventor); Fu, Johnny (Inventor); Mach, Joseph G. (Inventor); Santos, Jose B. (Inventor)


    An isotherm sensor tracks space vehicle temperatures by a thermal protection system (TPS) material during vehicle re-entry as a function of time, and surface recession through calibration, calculation, analysis and exposed surface modeling. Sensor design includes: two resistive conductors, wound around a tube, with a first end of each conductor connected to a constant current source, and second ends electrically insulated from each other by a selected material that becomes an electrically conductive char at higher temperatures to thereby complete an electrical circuit. The sensor conductors become shorter as ablation proceeds and reduced resistance in the completed electrical circuit (proportional to conductor length) is continually monitored, using measured end-to-end voltage change or current in the circuit. Thermocouple and/or piezoelectric measurements provide consistency checks on local temperatures.

  18. The ingestible thermal monitoring system (United States)

    Cutchis, Protagoras N.; Hogrefe, Arthur F.; Lesho, Jeffery C.


    A thermal monitoring system for measuring body core temperatures was developed that contains an ingestible pill which is both commandable and rechargeable, and which uses magnetic induction for command and telemetry as well as for recharging. The pill electronics consist of a battery power source, a crystal-controlled oscillator that drives a small air coil, and a command detection circuit. The resulting 262-kHz magnetilc field can be easily detected from a distance of 1 m. The pill oscillator functions at voltages less than 1 V, supplied by a single Ni-Cd battery, which must be recharged after 72 h of continuous transmission. The pill can be recalibrated periodically to compensate for long-term drift.

  19. Comparison between Different Air Distribution Systems

    DEFF Research Database (Denmark)

    Nielsen, Peter V.

    The aim of an air conditioning system is to remove excess heat in a room and replace room air with fresh air to obtain a high air quality. It is not sufficient to remove heat and contaminated air, it is also necessary to distribute and control the air movement in the room to create thermal comfort...... in the occupied zone. Most air distribution systems are based on mixing ventilation with ceiling or wall-mounted diffusers or on displacement ventilation with wall-mounted low velocity diffusers. New principles for room air distribution were introduced during the last decades, as the textile terminals mounted...... in the ceiling and radial diffusers with swirling flow also mounted in the ceiling. This paper addresses five air distribution systems in all, namely mixing ventilation from a wallmounted terminal, mixing ventilation from a ceiling-mounted diffuser, mixing ventilation from a ceiling-mounted diffuser...

  20. Displacements of Metallic Thermal Protection System Panels During Reentry (United States)

    Daryabeigi, Kamran; Blosser, Max L.; Wurster, Kathryn E.


    Bowing of metallic thermal protection systems for reentry of a previously proposed single-stage-to-orbit reusable launch vehicle was studied. The outer layer of current metallic thermal protection system concepts typically consists of a honeycomb panel made of a high temperature nickel alloy. During portions of reentry when the thermal protection system is exposed to rapidly varying heating rates, a significant temperature gradient develops across the honeycomb panel thickness, resulting in bowing of the honeycomb panel. The deformations of the honeycomb panel increase the roughness of the outer mold line of the vehicle, which could possibly result in premature boundary layer transition, resulting in significantly higher downstream heating rates. The aerothermal loads and parameters for three locations on the centerline of the windward side of this vehicle were calculated using an engineering code. The transient temperature distributions through a metallic thermal protection system were obtained using 1-D finite volume thermal analysis, and the resulting displacements of the thermal protection system were calculated. The maximum deflection of the thermal protection system throughout the reentry trajectory was 6.4 mm. The maximum ratio of deflection to boundary layer thickness was 0.032. Based on previously developed distributed roughness correlations, it was concluded that these defections will not result in tripping the hypersonic boundary layer.

  1. Solar thermal power systems. Program summary

    Energy Technology Data Exchange (ETDEWEB)


    Each of DOE's solar Thermal Power Systems projects funded and/or in existence during FY 1978 is described and the status as of September 30, 1978 is reflected. These projects are divided as follows: small thermal power applications, large thermal power applications, and advanced thermal technology. Also included are: 1978 project summary tables, bibliography, and an alphabetical index of contractors. (MHR)

  2. Finite element analysis of thermal stress distribution in different ...

    African Journals Online (AJOL)

    Purpose: Cervical lesions are restored with class V preparation. The aim of this study was to use a three-dimensional finite element method to carry out a thermal analysis of the temperature and stress distributions of three different restorative materials used for class V cavities of maxillary molar teeth. Materials and Methods: ...

  3. Power and Thermal Management of System-on-Chip

    DEFF Research Database (Denmark)

    Liu, Wei

    , are necessary at the chip design level. In this work, we investigate the power and thermal management of System-on- Chips (SoCs). Thermal analysis is performed in a SPICE simulation approach based on the electrical-thermal analogy. We investigate the impact of inter- connects on heat distribution......With greater integration of VLSI circuits, power consumption and power density have increased dramatically resulting in high chip temperatures and presenting a heat removal challenge. To effectively limit the high temperature inside a chip, thermal specific approaches, besides low power techniques...... of power efficient dividers on the energy consumption and thermal distribution within the FPU and the on-chip cache. We also characterize the temperature dependent static dissipation to evaluate the reduction in leakage obtained from the decrease in temperature....

  4. Distribution system modeling and analysis

    CERN Document Server

    Kersting, William H


    For decades, distribution engineers did not have the sophisticated tools developed for analyzing transmission systems-often they had only their instincts. Things have changed, and we now have computer programs that allow engineers to simulate, analyze, and optimize distribution systems. Powerful as these programs are, however, without a real understanding of the operating characteristics of a distribution system, engineers using the programs can easily make serious errors in their designs and operating procedures. Distribution System Modeling and Analysis helps prevent those errors. It gives readers a basic understanding of the modeling and operating characteristics of the major components of a distribution system. One by one, the author develops and analyzes each component as a stand-alone element, then puts them all together to analyze a distribution system comprising the various shunt and series devices for power-flow and short-circuit studies. He includes the derivation of all models and includes many num...

  5. Aerogel Modified Structural Thermal Protection System Project (United States)

    National Aeronautics and Space Administration — This program will mature and further develop structural syntactic foam insulated integral Thermal Protection System (TPS) designs and materials as an enabling...

  6. Distribution system modeling and analysis

    CERN Document Server

    Kersting, William H


    For decades, distribution engineers did not have the sophisticated tools developed for analyzing transmission systems-often they had only their instincts. Things have changed, and we now have computer programs that allow engineers to simulate, analyze, and optimize distribution systems. Powerful as these programs are, however, without a real understanding of the operating characteristics of a distribution system, engineers using the programs can easily make serious errors in their designs and operating procedures.Distribution System Modeling and Analysis helps prevent those errors. It gives re

  7. Lunar roving vehicle thermal control system. (United States)

    Elliott, R. G.; Paoletti, C. J.; Britt, M. A.


    A thermal control system was incorporated into the Lunar Roving Vehicle (LRV) to maintain temperature sensitive components within appropriate temperature limits during the translunar transportation phase, lunar surface operation, and quiescent periods between lunar traverses. This paper describes the thermal control system and discusses its thermal characteristics during all phases of operation. The basic concept is a passive system which stores internally generated energy during operation with subsequent radiation to space. The external environments are regulated by selected radiative surface finishes. Multi-layer insulation blankets, space radiators, flexible thermal straps, and fusible mass heat sinks were designed to control the temperatures of the electronic components.

  8. Distributed Multimedia Systems

    NARCIS (Netherlands)

    Mullender, Sape J.

    Multimedia systems will allow professionals worldwide to collaborate more effectively and to travel substantially less. But for multimedia systems to be effective, a good systems infrastructure is essential. In particular, support is needed for global and consistent sharing of information, for

  9. Water Treatment Technology - Distribution Systems. (United States)

    Ross-Harrington, Melinda; Kincaid, G. David

    One of twelve water treatment technology units, this student manual on distribution systems provides instructional materials for six competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on the following areas: types of pipe for distribution systems, types…

  10. Uniform Interfaces for Distributed Systems. (United States)


    Also TER 051.3, Reseau Cyclades. 66] R.A. Faneuf. The National Software Works: Operational issues in a distributed processing system. Proc. National...editor. Distributed Systems Architecture and Implementation: An Advanced Course. To be published by Springer-Verlag. Also Lecture Notes, Institut fuer

  11. Cronus: A Distributed Operating System. (United States)


    reduce the inventory of spare parts necessary to achieve a satisfactory level of backup reliability. (12) "Distributed Operating System Design Study...that the success of the distributed system concept in Air Force command and control environments will to some extent be dependent on the managemen ~t of

  12. Parameter identification in distributed systems (United States)

    Baruh, H.; Meirovitch, L.


    This paper describes a method for the identification of the parameters entering into the equations of motion of distributed systems. Because the motion of distributed systems is described in terms of partial differential equations, these parameters are in general continuous functions of the spatial variables. For vibrating systems, these parameters ordinarily represent the mass, stiffness and damping distributions. In this paper, these distributions are expanded in terms of finite series of known functions of the spatial variables multiplied by undetermined coefficients. It is assumed that the nature of the equations of motion is known and that a limited number of eigenvalues and eigenfunctions is identified in advance. Use is then made of the least squares method, in conjunction with the eigenfunctions' orthogonality, to compute the undetermined coefficients, thus identifying the system distributed parameters. A method for the identification of the eigensolution is also presented. The procedure for the identification of the eigensolution and of the system parameters is demonstrated via a numerical example.

  13. Thermal Signature Identification System (TheSIS) (United States)

    Merritt, Scott; Bean, Brian


    We characterize both nonlinear and high order linear responses of fiber-optic and optoelectronic components using spread spectrum temperature cycling methods. This Thermal Signature Identification System (TheSIS) provides much more detail than conventional narrowband or quasi-static temperature profiling methods. This detail allows us to match components more thoroughly, detect subtle reversible shifts in performance, and investigate the cause of instabilities or irreversible changes. In particular, we create parameterized models of athermal fiber Bragg gratings (FBGs), delay line interferometers (DLIs), and distributed feedback (DFB) lasers, then subject the alternative models to selection via the Akaike Information Criterion (AIC). Detailed pairing of components, e.g. FBGs, is accomplished by means of weighted distance metrics or norms, rather than on the basis of a single parameter, such as center wavelength.

  14. Comparison of thermal cracking and hydro-cracking yield distributions

    Energy Technology Data Exchange (ETDEWEB)

    Romero, S.; Sayles, S. [KBC Advanced Technologies Inc., Houston, TX (United States)


    Operators of bitumen upgraders are faced with the challenge of obtaining maximum performance from existing equipment whose performance is already pushed to the limits. The main constraint is the primary upgrader processes, notably coking and hydrocracking. Under the current economic conditions, funding for new equipment is difficult. However, changes can be made to optimize unit performance by better understanding the basic kinetics in thermal cracking and hydrocracking. This paper reviewed the yield distribution differences between thermal cracking and hydrocracking to provide insight into the basic components of operational changes. The objective was to compare yields, product quality distributions and the elemental balances. The opportunities to increase production and improve performance were then analyzed quantitatively within the existing unit equipment limits. tabs., figs.

  15. Thermal Management Tools for Propulsion System Trade Studies and Analysis (United States)

    McCarthy, Kevin; Hodge, Ernie


    Energy-related subsystems in modern aircraft are more tightly coupled with less design margin. These subsystems include thermal management subsystems, vehicle electric power generation and distribution, aircraft engines, and flight control. Tighter coupling, lower design margins, and higher system complexity all make preliminary trade studies difficult. A suite of thermal management analysis tools has been developed to facilitate trade studies during preliminary design of air-vehicle propulsion systems. Simulink blocksets (from MathWorks) for developing quasi-steady-state and transient system models of aircraft thermal management systems and related energy systems have been developed. These blocksets extend the Simulink modeling environment in the thermal sciences and aircraft systems disciplines. The blocksets include blocks for modeling aircraft system heat loads, heat exchangers, pumps, reservoirs, fuel tanks, and other components at varying levels of model fidelity. The blocksets have been applied in a first-principles, physics-based modeling and simulation architecture for rapid prototyping of aircraft thermal management and related systems. They have been applied in representative modern aircraft thermal management system studies. The modeling and simulation architecture has also been used to conduct trade studies in a vehicle level model that incorporates coupling effects among the aircraft mission, engine cycle, fuel, and multi-phase heat-transfer materials.

  16. Analysis Model for Domestic Hot Water Distribution Systems: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Maguire, J.; Krarti, M.; Fang, X.


    A thermal model was developed to estimate the energy losses from prototypical domestic hot water (DHW) distribution systems for homes. The developed model, using the TRNSYS simulation software, allows researchers and designers to better evaluate the performance of hot water distribution systems in homes. Modeling results were compared with past experimental study results and showed good agreement.

  17. Power Aware Distributed Systems (United States)


    R. Meyer, M. Takai, Y.A. Chan, X. Zeng, J. Marting , H.Y. Song, “Parsec: a parallel simulation environment for complex systems,” Computer, Vol.31...Bearing360 180 Num. Mikes Num. Samples 7 6 2 4 5 M 8 12 18 90 1024 512 32 64 128 256 Search Angles S EW N LOB Confidence 3 B 2° 3° 4° 5° PA/ DTA /D


    Directory of Open Access Journals (Sweden)

    Patryk Różyło


    Full Text Available The study involved performing a numerical thermal analysis of selected components in a car braking system. The primary goal of the study was to determine the regions which are the most susceptible to variations in temperature, and to determine the degree of thermal impact upon them. The analysis was performed using the Abaqus environment. The examined components of the braking system were made of materials reflecting the mechanical properties of the real subassemblies. The FEM analysis enabled determination of the distribution of temperature in the system with respect to the properties of the investigated materials and applied boundary conditions.

  19. Thermal energy systems design and analysis

    CERN Document Server

    Penoncello, Steven G


    IntroductionThermal Energy Systems Design and AnalysisSoftwareThermal Energy System TopicsUnits and Unit SystemsThermophysical PropertiesEngineering DesignEngineering EconomicsIntroductionCommon Engineering Economics NomenclatureEconomic Analysis Tool: The Cash Flow DiagramTime Value of MoneyTime Value of Money ExamplesUsing Software to Calculate Interest FactorsEconomic Decision MakingDepreciation and TaxesProblemsAnalysis of Thermal Energy SystemsIntroductionNomenclatureThermophysical Properties of SubstancesSuggested Thermal Energy Systems Analysis ProcedureConserved and Balanced QuantitiesConservation of MassConservation of Energy (The First Law of Thermodynamics)Entropy Balance (The Second Law of Thermodynamics)Exergy Balance: The Combined LawEnergy and Exergy Analysis of Thermal Energy CyclesDetailed Analysis of Thermal Energy CyclesProblemsFluid Transport in Thermal Energy SystemsIntroductionPiping and Tubing StandardsFluid Flow FundamentalsValves and FittingsDesign and Analysis of Pipe NetworksEconomi...

  20. A simplistic pedagogical formulation of a thermal speed distribution ...

    Indian Academy of Sciences (India)

    Our approach, a logical extension of that proposed by Maxwell, will first recapitulate what is taught and known in the UG class and then present a methodology inspired from the Maxwell–Boltzmann framework that will help students to understand and derive the physics of relativistic thermal systems. The methodology uses ...

  1. The Entropy Production Distribution in Non-Markovian Thermal Baths

    Directory of Open Access Journals (Sweden)

    José Inés Jiménez-Aquino


    Full Text Available In this work we study the distribution function for the total entropy production of a Brownian particle embedded in a non-Markovian thermal bath. The problem is studied in the overdamped approximation of the generalized Langevin equation, which accounts for a friction memory kernel characteristic of a Gaussian colored noise. The problem is studied in two physical situations: (i when the particle in the harmonic trap is subjected to an arbitrary time-dependent driving force; and (ii when the minimum of the harmonic trap is arbitrarily dragged out of equilibrium by an external force. By assuming a natural non Markovian canonical distribution for the initial conditions, the distribution function for the total entropy production becomes a non Gaussian one. Its characterization is then given through the first three cumulants.

  2. Modeling thermal effects in braking systems of railway vehicles

    Directory of Open Access Journals (Sweden)

    Milošević Miloš S.


    Full Text Available The modeling of thermal effects has become increasingly important in product design in different transport means, road vehicles, airplanes, railway vehicles, and so forth. The thermal analysis is a very important stage in the study of braking systems, especially of railway vehicles, where it is necessary to brake huge masses, because the thermal load of a braked railway wheel prevails compared to other types of loads. In the braking phase, kinetic energy transforms into thermal energy resulting in intense heating and high temperature states of railway wheels. Thus induced thermal loads determine thermomechanical behavior of the structure of railway wheels. In cases of thermal overloads, which mainly occur as a result of long-term braking on down-grade railroads, the generation of stresses and deformations occurs, whose consequences are the appearance of cracks on the rim of a wheel and the final total wheel defect. The importance to precisely determine the temperature distribution caused by the transfer process of the heat generated during braking due to the friction on contact surfaces of the braking system makes it a challenging research task. Therefore, the thermal analysis of a block-braked solid railway wheel of a 444 class locomotive of the national railway operator Serbian Railways is processed in detail in this paper, using analytical and numerical modeling of thermal effects during long-term braking for maintaining a constant speed on a down-grade railroad.

  3. Numerical investigation of temperature distribution and thermal performance while charging-discharging thermal energy in aquifer

    NARCIS (Netherlands)

    Ganguly, S.; Mohan Kumar, M.S.; Date, Abhijit; Akbarzadeh, Aliakbar


    A three-dimensional (3D) coupled thermo-hydrogeological numerical model for a confined aquifer thermal energy storage (ATES) system underlain and overlain by rock media has been presented in this paper. The ATES system operates in cyclic mode. The model takes into account heat transport processes of

  4. Energy efficient distributed computing systems

    CERN Document Server

    Lee, Young-Choon


    The energy consumption issue in distributed computing systems raises various monetary, environmental and system performance concerns. Electricity consumption in the US doubled from 2000 to 2005.  From a financial and environmental standpoint, reducing the consumption of electricity is important, yet these reforms must not lead to performance degradation of the computing systems.  These contradicting constraints create a suite of complex problems that need to be resolved in order to lead to 'greener' distributed computing systems.  This book brings together a group of outsta

  5. Space shuttle heat pipe thermal control systems (United States)

    Alario, J.


    Heat pipe (HP) thermal control systems designed for possible space shuttle applications were built and tested under this program. They are: (1) a HP augmented cold rail, (2) a HP/phase change material (PCM) modular heat sink and (3) a HP radiating panel for compartment temperature control. The HP augmented cold rail is similar to a standard two-passage fluid cold rail except that it contains an integral, centrally located HP throughout its length. The central HP core helps to increase the local power density capability by spreading concentrated heat inputs over the entire rail. The HP/PCM modular heat sink system consists of a diode HP connected in series to a standard HP that has a PCM canister attached to its mid-section. It is designed to connect a heat source to a structural heat sink during normal operation, and to automatically decouple from it and sink to the PCM whenever structural temperatures are too high. The HP radiating panel is designed to conductively couple the panel feeder HPs directly to a fluid line that serves as a source of waste heat. It is a simple strap-on type of system that requires no internal or external line modifications to distribute the heat to a large radiating area.

  6. Coordination control of distributed systems

    CERN Document Server

    Villa, Tiziano


    This book describes how control of distributed systems can be advanced by an integration of control, communication, and computation. The global control objectives are met by judicious combinations of local and nonlocal observations taking advantage of various forms of communication exchanges between distributed controllers. Control architectures are considered according to  increasing degrees of cooperation of local controllers:  fully distributed or decentralized control,  control with communication between controllers,  coordination control, and multilevel control.  The book covers also topics bridging computer science, communication, and control, like communication for control of networks, average consensus for distributed systems, and modeling and verification of discrete and of hybrid systems. Examples and case studies are introduced in the first part of the text and developed throughout the book. They include: control of underwater vehicles, automated-guided vehicles on a container terminal, contro...

  7. NDE for Ablative Thermal Protection Systems Project (United States)

    National Aeronautics and Space Administration — This program addresses the need for non-destructive evaluation (NDE) methods for quality assessment and defect evaluation of thermal protection systems (TPS),...

  8. NDE for Ablative Thermal Protection Systems Project (United States)

    National Aeronautics and Space Administration — This program addresses the need for non-destructive evaluation (NDE) methods for quality assessment and defect evaluation of thermal protection systems (TPS). Novel...

  9. Transient Thermal Analyses of Passive Systems on SCEPTOR X-57 (United States)

    Chin, Jeffrey C.; Schnulo, Sydney L.; Smith, Andrew D.


    As efficiency, emissions, and noise become increasingly prominent considerations in aircraft design, turning to an electric propulsion system is a desirable solution. Achieving the intended benefits of distributed electric propulsion (DEP) requires thermally demanding high power systems, presenting a different set of challenges compared to traditional aircraft propulsion. The embedded nature of these heat sources often preclude the use of traditional thermal management systems in order to maximize performance, with less opportunity to exhaust waste heat to the surrounding environment. This paper summarizes the thermal analyses of X-57 vehicle subsystems that don't employ externally air-cooled heat sinks. The high-power battery, wires, high-lift motors, and aircraft outer surface are subjected to heat loads with stringent thermal constraints. The temperature of these components are tracked transiently, since they never reach a steady-state equilibrium. Through analysis and testing, this report demonstrates that properly characterizing the material properties is key to accurately modeling peak temperature of these systems, with less concern for spatial thermal gradients. Experimentally validated results show the thermal profile of these systems can be sufficiently estimated using reduced order approximations.

  10. Thermal History Devices, Systems For Thermal History Detection, And Methods For Thermal History Detection

    KAUST Repository

    Caraveo Frescas, Jesus Alfonso


    Embodiments of the present disclosure include nanowire field-effect transistors, systems for temperature history detection, methods for thermal history detection, a matrix of field effect transistors, and the like.

  11. Hot flow model with a hybrid (thermal/nonthermal) particle distributions and its application to low luminosity black-hole systems. (United States)

    Stepnik, Agnieszka; Niedzwiecki, Andrzej; Xie, Fu-Guo; Szanecki, Michal


    We study the X-ray spectra of hot accretion flows (ADAFs) using a precise model involving (1) an exact, Monte Carlo computation of the global Comptonization effect, (2) a general relativistic description of both the flow structure and radiative processes and (3) a description of the relevant hadronic processes. We find that the model can be reconciled with the X-ray data for low luminosity AGNs only if the hybrid distribution of electrons, with ~10% energy content in the nonthermal component, is taken into account. Such a model also allows to explain differences between the X-ray spectra of AGNs and black-hole transients. We discuss differences between the models with nonthermal electrons provided by pion-production processes in the two-temperature and by direct acceleration processes. We also present our newly developed XSPEC model for the hot flow spectra and its application to several low luminosity objects.

  12. A New Large Scale Distributed System: Object Distribution

    NARCIS (Netherlands)

    Kavitha Muthukrishnan, K.; Meratnia, Nirvana; Koprinkov, G.T.; Lijding, M.E.M.; Havinga, Paul J.M.

    We introduce in this work Object Distribution System, a distributed system based on distribution models used in everyday life (e.g. food distribution chains, newspapers, etc.). This system is designed to scale correctly in a wide area network, using weak consistency replication mechanisms. It is

  13. RBAC administration in distributed systems

    NARCIS (Netherlands)

    Dekker, M.A.C.; Crampton, J.; Etalle, Sandro; Li, N.

    Large and distributed access control systems are increasingly common, for example in health care. In such settings, access control policies may become very complex, thus complicating correct and efficient adminstration of the access control system. Despite being one of the most widely used access

  14. Systems Measures of Water Distribution System Resilience

    Energy Technology Data Exchange (ETDEWEB)

    Klise, Katherine A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Murray, Regan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Walker, La Tonya Nicole [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)


    Resilience is a concept that is being used increasingly to refer to the capacity of infrastructure systems to be prepared for and able to respond effectively and rapidly to hazardous events. In Section 2 of this report, drinking water hazards, resilience literature, and available resilience tools are presented. Broader definitions, attributes and methods for measuring resilience are presented in Section 3. In Section 4, quantitative systems performance measures for water distribution systems are presented. Finally, in Section 5, the performance measures and their relevance to measuring the resilience of water systems to hazards is discussed along with needed improvements to water distribution system modeling tools.

  15. Thermally stimulated currents in glassy systems

    CERN Document Server

    Halpern, V


    A common interpretation of the results of thermally stimulated current experiments is in terms of a fixed set of states present in the system with a range of activation energies, of which specific subsets are selected and identified by thermal slicing (TS) (or fractional polarization) experiments at different polarization temperatures T sub p. On the other hand, such an interpretation is not consistent with many current theories of supercooled liquids and of the glass transition. The results are presented of our calculations on thermally activated Fredrickson-Andersen model systems, which indicate that the TS technique does identify the isothermal response of the system at T sub p. However, this response need not be associated with specific states present in the system, but can arise for instance from a competition between different relaxation paths for the dipole moments of the individual particles. In addition, the compensation law is found to be obeyed for systems with and without cooperative effects, so t...

  16. Thermal energy storage devices, systems, and thermal energy storage device monitoring methods (United States)

    Tugurlan, Maria; Tuffner, Francis K; Chassin, David P.


    Thermal energy storage devices, systems, and thermal energy storage device monitoring methods are described. According to one aspect, a thermal energy storage device includes a reservoir configured to hold a thermal energy storage medium, a temperature control system configured to adjust a temperature of the thermal energy storage medium, and a state observation system configured to provide information regarding an energy state of the thermal energy storage device at a plurality of different moments in time.

  17. A Thermal Test System for Helmet Cooling Studies

    Directory of Open Access Journals (Sweden)

    Shaun Fitzgerald


    Full Text Available One of the primary causes of discomfort to both irregular and elite cyclists is heat entrapment by a helmet resulting in overheating and excessive sweating of the head. To accurately assess the cooling effectiveness of bicycle helmets, a heated plastic thermal headform has been developed. The construction consists of a 3D-printed headform of low thermal conductivity with an internal layer of high thermal mass that is heated to a constant uniform temperature by an electrical heating element. Testing is conducted in a wind tunnel where the heater power remains constant and the resulting surface temperature distribution is directly measured by 36 K-type thermocouples embedded within the surface of the head in conjunction with a thermal imaging camera. Using this new test system, four bicycle helmets were studied in order to measure their cooling abilities and to identify ‘hot spots’ where cooling performance is poor.

  18. Compressed sensing for distributed systems

    CERN Document Server

    Coluccia, Giulio; Magli, Enrico


    This book presents a survey of the state-of-the art in the exciting and timely topic of compressed sensing for distributed systems. It has to be noted that, while compressed sensing has been studied for some time now, its distributed applications are relatively new. Remarkably, such applications are ideally suited to exploit all the benefits that compressed sensing can provide. The objective of this book is to provide the reader with a comprehensive survey of this topic, from the basic concepts to different classes of centralized and distributed reconstruction algorithms, as well as a comparison of these techniques. This book collects different contributions on these aspects. It presents the underlying theory in a complete and unified way for the first time, presenting various signal models and their use cases. It contains a theoretical part collecting latest results in rate-distortion analysis of distributed compressed sensing, as well as practical implementations of algorithms obtaining performance close to...

  19. Energy Efficiency of Distributed Environmental Control Systems

    Energy Technology Data Exchange (ETDEWEB)

    Khalifa, H. Ezzat; Isik, Can; Dannenhoffer, John F. III


    In this report, we present an analytical evaluation of the potential of occupant-regulated distributed environmental control systems (DECS) to enhance individual occupant thermal comfort in an office building with no increase, and possibly even a decrease in annual energy consumption. To this end we developed and applied several analytical models that allowed us to optimize comfort and energy consumption in partitioned office buildings equipped with either conventional central HVAC systems or occupant-regulated DECS. Our approach involved the following interrelated components: 1. Development of a simplified lumped-parameter thermal circuit model to compute the annual energy consumption. This was necessitated by the need to perform tens of thousands of optimization calculations involving different US climatic regions, and different occupant thermal preferences of a population of ~50 office occupants. Yearly transient simulations using TRNSYS, a time-dependent building energy modeling program, were run to determine the robustness of the simplified approach against time-dependent simulations. The simplified model predicts yearly energy consumption within approximately 0.6% of an equivalent transient simulation. Simulations of building energy usage were run for a wide variety of climatic regions and control scenarios, including traditional “one-size-fits-all” (OSFA) control; providing a uniform temperature to the entire building, and occupant-selected “have-it-your-way” (HIYW) control with a thermostat at each workstation. The thermal model shows that, un-optimized, DECS would lead to an increase in building energy consumption between 3-16% compared to the conventional approach depending on the climate regional and personal preferences of building occupants. Variations in building shape had little impact in the relative energy usage. 2. Development of a gradient-based optimization method to minimize energy consumption of DECS while keeping each occupant

  20. Truncated thermal equilibrium distribution for intense beam propagation

    Directory of Open Access Journals (Sweden)

    Ronald C. Davidson


    Full Text Available An intense charged particle beam with directed kinetic energy (γ_{b}-1m_{b}c^{2} propagates in the z direction through an applied focusing field with transverse focusing force modeled by F_{foc}=-γ_{b}m_{b}ω_{β⊥}^{2}x_{⊥} in the smooth-focusing approximation. This paper examines properties of the axisymmetric, truncated thermal equilibrium distribution F_{b}(r,p_{⊥}=Aexp⁡(-H_{⊥}/T[over ^]_{⊥b}⊕(H_{⊥}-E_{b}, where A, T[over ^]_{⊥b}, and E_{b} are positive constants, and H_{⊥} is the Hamiltonian for transverse particle motion. The equilibrium profiles for beam number density, n_{b}(r=∫d^{2}pF_{b}(r,p_{⊥}, and transverse temperature, T_{⊥b}(r=[n_{b}(r]^{-1}∫d^{2}p(p_{⊥}^{2}/2γ_{b}m_{b}F_{b}(r,p_{⊥}, are calculated self-consistently including space-charge effects. Several properties of the equilibrium profiles are noteworthy. For example, the beam has a sharp outer edge radius r_{b} with n_{b}(r≥r_{b}=0, where r_{b} depends on the value of E_{b}/T[over ^]_{⊥b}. In addition, unlike the choice of a semi-Gaussian distribution, F_{b}^{SG}=Aexp⁡(-p_{⊥}^{2}/2γ_{b}m_{b}T[over ^]_{⊥b}⊕(r-r_{b}, the truncated thermal equilibrium distribution F_{b}(r,p depends on (r,p only through the single-particle constant of the motion H_{⊥} and is therefore a true steady-state solution (∂/∂t=0 of the nonlinear Vlasov-Maxwell equations.

  1. Distribution system analysis and automation

    CERN Document Server

    Gers, Juan


    A comprehensive guide to techniques that allow engineers to simulate, analyse and optimise power distribution systems which combined with automation, underpin the emerging concept of the "smart grid". This book is supported by theoretical concepts with real-world applications and MATLAB exercises.

  2. Distributed Systems: The Hard Problems

    CERN Multimedia

    CERN. Geneva


    **Nicholas Bellerophon** works as a client services engineer at Basho Technologies, helping customers setup and run distributed systems at scale in the wild. He has also worked in massively multiplayer games, and recently completed a live scalable simulation engine. He is an avid TED-watcher with interests in many areas of the arts, science, and engineering, including of course high-energy physics.

  3. Thermal stress analysis of space shuttle orbiter wing skin panel and thermal protection system (United States)

    Ko, William L.; Jenkins, Jerald M.


    Preflight thermal stress analysis of the space shuttle orbiter wing skin panel and the thermal protection system (TPS) was performed. The heated skin panel analyzed was rectangular in shape and contained a small square cool region at its center. The wing skin immediately outside the cool region was found to be close to the state of elastic instability in the chordwise direction based on the conservative temperature distribution. The wing skin was found to be quite stable in the spanwise direction. The potential wing skin thermal instability was not severe enough to tear apart the strain isolation pad (SIP) layer. Also, the preflight thermal stress analysis was performed on the TPS tile under the most severe temperature gradient during the simulated reentry heating. The tensile thermal stress induced in the TPS tile was found to be much lower than the tensile strength of the TPS material. The thermal bending of the TPS tile was not severe enough to cause tearing of the SIP layer.

  4. The ATLAS distributed analysis system (United States)

    Legger, F.; Atlas Collaboration


    In the LHC operations era, analysis of the multi-petabyte ATLAS data sample by globally distributed physicists is a challenging task. To attain the required scale the ATLAS Computing Model was designed around the concept of Grid computing, realized in the Worldwide LHC Computing Grid (WLCG), the largest distributed computational resource existing in the sciences. The ATLAS experiment currently stores over 140 PB of data and runs about 140,000 concurrent jobs continuously at WLCG sites. During the first run of the LHC, the ATLAS Distributed Analysis (DA) service has operated stably and scaled as planned. More than 1600 users submitted jobs in 2012, with 2 million or more analysis jobs per week, peaking at about a million jobs per day. The system dynamically distributes popular data to expedite processing and maximally utilize resources. The reliability of the DA service is high and steadily improving; Grid sites are continually validated against a set of standard tests, and a dedicated team of expert shifters provides user support and communicates user problems to the sites. Both the user support techniques and the direct feedback of users have been effective in improving the success rate and user experience when utilizing the distributed computing environment. In this contribution a description of the main components, activities and achievements of ATLAS distributed analysis is given. Several future improvements being undertaken will be described.

  5. Generalized Thermalization in an Integrable Lattice System (United States)

    Cassidy, Amy C.; Clark, Charles W.; Rigol, Marcos


    After a quench, observables in an integrable system may not relax to the standard thermal values, but can relax to the ones predicted by the generalized Gibbs ensemble (GGE) [M. Rigol et al., Phys. Rev. Lett. 98, 050405 (2007)PRLTAO0031-900710.1103/PhysRevLett.98.050405]. The GGE has been shown to accurately describe observables in various one-dimensional integrable systems, but the origin of its success is not fully understood. Here we introduce a microcanonical version of the GGE and provide a justification of the GGE based on a generalized interpretation of the eigenstate thermalization hypothesis, which was previously introduced to explain thermalization of nonintegrable systems. We study relaxation after a quench of one-dimensional hard-core bosons in an optical lattice. Exact numerical calculations for up to 10 particles on 50 lattice sites (≈1010 eigenstates) validate our approach.

  6. DC Distribution Systems and Microgrids

    DEFF Research Database (Denmark)

    Dragicevic, Tomislav; Anvari-Moghaddam, Amjad; Quintero, Juan Carlos Vasquez


    A qualitative overview of different hardware topologies and control systems for DC MGs has been presented in this chapter. Some challenges and design considerations of DC protections systems have also been discussed. Finally, applications of DC MGs in emerging smart grid applications have been su...... in different industries and gradually lead to new ways of rethinking of the future power distribution philosophies, especially with the emergence of SSTs. Research in DC systems, especially in the power electronics-based technologies will be highly attractive in the future....

  7. Distributed optimization system and method (United States)

    Hurtado, John E.; Dohrmann, Clark R.; Robinett, III, Rush D.


    A search system and method for controlling multiple agents to optimize an objective using distributed sensing and cooperative control. The search agent can be one or more physical agents, such as a robot, and can be software agents for searching cyberspace. The objective can be: chemical sources, temperature sources, radiation sources, light sources, evaders, trespassers, explosive sources, time dependent sources, time independent sources, function surfaces, maximization points, minimization points, and optimal control of a system such as a communication system, an economy, a crane, and a multi-processor computer.

  8. Solar thermal systems successful planning and construction

    CERN Document Server

    Peuser, Dr Felix A; Schnauss, Martin


    Solar Thermal Systems summarizes the theoretical and practical knowledge gained from over 20 years of research, implementation and operation of thermal solar installations. This work provides answers to a variety of key questions by examining current solar installations, drawing upon past experiences and making proposals for future planning.- how do system components and materials behave under continuous operation?- which components have proven themselves and how are they used properly?- what are the causes of defects and how can they be avoided?- how long is the service life of modern solar i

  9. Thermal integration of trigeneration systems

    Energy Technology Data Exchange (ETDEWEB)

    Teopa Calva, E. [Institute for Scientific Research, University of Guanajuato, Cerro de la Venada s/n Pueblito de Rocha, C.P. 36040, Guanajuato, Gto, Mexico (Mexico); Picon Nunez, M. [Mexican Petroleum Institute, Sistemas Energeticos Avanzados-PIMAS, Eje Central Lazaro Cardenas No. 152, Col. San Bartolo Atepehuacan, C.P. 07730, Mexico, DF (Mexico)]. E-mail:; Rodriguez Toral, M.A. [Mexican Petroleum Institute, Sistemas Energeticos Avanzados-PIMAS, Eje Central Lazaro Cardenas No. 152, Col. San Bartolo Atepehuacan, C.P. 07730, Mexico, DF (Mexico)


    Trigeneration can be considered as a special case of the application of cogeneration systems where a fraction of the shaft work or residual heat is used for running a refrigeration system. This work focuses on trigeneration schemes where a gas turbine is used as a prime mover for power production and cooling is generated by a typical compression-refrigeration system. In most applications, a gas turbine will meet either the process power requirements or the heating needs, but it is unlikely that both would be satisfied simultaneously in the most efficient manner. The selection of the gas turbine that minimizes the heat losses to the ambient while supplying the required power can be readily accomplished by superimposing the turbine exhaust gas temperature profile to the process streams profile in a T vs enthalpy curve. This is because the maximum overall efficiency depends on the process heat and power demands and on the shape of the heat demand profile of the process. The use of the thermodynamic model helps to simulate the main components of the system and permits a fast and interactive way to design the optimum trigeneration scheme using the performance data of commercial gas turbines.

  10. Solar thermal power systems. Summary report

    Energy Technology Data Exchange (ETDEWEB)


    The work accomplished by the Aerospace Corporation from April 1973 through November 1979 in the mission analysis of solar thermal power systems is summarized. Sponsorship of this effort was initiated by the National Science Foundation, continued by the Energy Research and Development Administration, and most recently directed by the United States Department of Energy, Division of Solar Thermal Systems. Major findings and conclusions are sumarized for large power systems, small power systems, solar total energy systems, and solar irrigation systems, as well as special studies in the areas of energy storage, industrial process heat, and solar fuels and chemicals. The various data bases and computer programs utilized in these studies are described, and tables are provided listing financial and solar cost assumptions for each study. An extensive bibliography is included to facilitate review of specific study results and methodology.

  11. Distributed Persistent Identifiers System Design

    Directory of Open Access Journals (Sweden)

    Pavel Golodoniuc


    Full Text Available The need to identify both digital and physical objects is ubiquitous in our society. Past and present persistent identifier (PID systems, of which there is a great variety in terms of technical and social implementation, have evolved with the advent of the Internet, which has allowed for globally unique and globally resolvable identifiers. PID systems have, by in large, catered for identifier uniqueness, integrity, and persistence, regardless of the identifier’s application domain. Trustworthiness of these systems has been measured by the criteria first defined by Bütikofer (2009 and further elaborated by Golodoniuc 'et al'. (2016 and Car 'et al'. (2017. Since many PID systems have been largely conceived and developed by a single organisation they faced challenges for widespread adoption and, most importantly, the ability to survive change of technology. We believe that a cause of PID systems that were once successful fading away is the centralisation of support infrastructure – both organisational and computing and data storage systems. In this paper, we propose a PID system design that implements the pillars of a trustworthy system – ensuring identifiers’ independence of any particular technology or organisation, implementation of core PID system functions, separation from data delivery, and enabling the system to adapt for future change. We propose decentralisation at all levels — persistent identifiers and information objects registration, resolution, and data delivery — using Distributed Hash Tables and traditional peer-to-peer networks with information replication and caching mechanisms, thus eliminating the need for a central PID data store. This will increase overall system fault tolerance thus ensuring its trustworthiness. We also discuss important aspects of the distributed system’s governance, such as the notion of the authoritative source and data integrity

  12. Thermal Effects on the Single-Mode Regime of Distributed Modal Filtering Rod Fiber

    DEFF Research Database (Denmark)

    Coscelli, Enrico; Poli, Federica; Alkeskjold, Thomas Tanggaard


    Power scaling of fiber laser systems requires the development of innovative active fibers, capable of providing high pump absorption, ultralarge effective area, high-order mode suppression, and resilience to thermal effects. Thermally induced refractive index change has been recently appointed...... as one major limitation to the achievable power, causing degradation of the modal properties and preventing to obtain stable diffraction-limited output beam. In this paper, the effects of thermally induced refractive index change on the guiding properties of a double-cladding distributed modal filtering...... rod-type photonic crystal fiber, which exploits resonant coupling with high-index elements to suppress high-order modes, are thoroughly investigated. A computationally efficient model has been developed to calculate the refractive index change due to the thermo-optical effect, and it has been...

  13. Hazards Data Distribution System (HDDS) (United States)

    Jones, Brenda; Lamb, Rynn M.


    When emergencies occur, first responders and disaster response teams often need rapid access to aerial photography and satellite imagery that is acquired before and after the event. The U.S. Geological Survey (USGS) Hazards Data Distribution System (HDDS) provides quick and easy access to pre- and post-event imagery and geospatial datasets that support emergency response and recovery operations. The HDDS provides a single, consolidated point-of-entry and distribution system for USGS-hosted remotely sensed imagery and other geospatial datasets related to an event response. The data delivery services are provided through an interactive map-based interface that allows emergency response personnel to rapidly select and download pre-event ("baseline") and post-event emergency response imagery.

  14. Distributed fiber optic moisture intrusion sensing system (United States)

    Weiss, Jonathan D.


    Method and system for monitoring and identifying moisture intrusion in soil such as is contained in landfills housing radioactive and/or hazardous waste. The invention utilizes the principle that moist or wet soil has a higher thermal conductance than dry soil. The invention employs optical time delay reflectometry in connection with a distributed temperature sensing system together with heating means in order to identify discrete areas within a volume of soil wherein temperature is lower. According to the invention an optical element and, optionally, a heating element may be included in a cable or other similar structure and arranged in a serpentine fashion within a volume of soil to achieve efficient temperature detection across a large area or three dimensional volume of soil. Remediation, moisture countermeasures, or other responsive action may then be coordinated based on the assumption that cooler regions within a soil volume may signal moisture intrusion where those regions are located.

  15. Power Capability in Low Voltage DC Distribution Systems

    Directory of Open Access Journals (Sweden)

    C.O. Gecan


    Full Text Available Recent developments in power electronics components enable the use of power electronics in Low Voltage (LV networks. This development makes the model of a Low Voltage Direct Current (LVDC distribution system possible. The technical and economical benefits of this technology make possible the alternative hypothesis of using DC instead of AC distribution systems. Some aspects, such as increasing the capability of the existing lines, interconnecting distributed generation units and even supplying in DC some loads are creating additional requirements of using a LVDC distribution system. The paper presents some general considerations regarding cables used in a LVAC distribution system and different line reconfigurations witch enable the use of cobles in a LVDC distribution system. The reconfigurations are presented in respect of the DC network topologies: unipolar and bipolar. The central aim of this paper is to investigate capability of power transmission and to calculate the transmission distance for cables used in Low Voltage AC and DC distribution systems. Capability computation is considered in respect of two constrains imposed in the cables cross section selection: cable thermal limit and the maximum allowable voltage drop. Cable thermal limit is represented in calculations by the maximum rated current. The equations used to calculate the power capability are presented for single-phase and threephase AC networks and unipolar and bipolar DC networks. Based on these equations, comparisons between power capability of cables with different cross sections used in Low Voltage DC and AC distribution systems are realized and presented.

  16. Towards an Ultimate Battery Thermal Management System

    DEFF Research Database (Denmark)

    Khan, Mohammad Rezwan; Swierczynski, Maciej Jozef; Kær, Søren Knudsen


    The prevailing standards and scientific literature offer a wide range of options for the construction of a battery thermal management system (BTMS). The design of an innovative yet well-functioning BTMS requires strict supervision, quality audit and continuous improvement of the whole process....... It must address all the current quality and safety (Q&S) standards. In this review article, an effective battery thermal management is sought considering the existing battery Q&S standards and scientific literature. The article contains a broad overview of the current existing standards and literature...

  17. The ATLAS Distributed Analysis System

    CERN Document Server

    Legger, F; The ATLAS collaboration; Pacheco Pages, A; Stradling, A


    In the LHC operations era, analysis of the multi-petabyte ATLAS data sample by globally distributed physicists is a challenging task. To attain the required scale the ATLAS Computing Model was designed around the concept of grid computing, realized in the Worldwide LHC Computing Grid (WLCG), the largest distributed computational resource existing in the sciences. The ATLAS experiment currently stores over 140 PB of data and runs about 140,000 concurrent jobs continuously at WLCG sites. During the first run of the LHC, the ATLAS Distributed Analysis (DA) service has operated stably and scaled as planned. More than 1600 users submitted jobs in 2012, with 2 million or more analysis jobs per week, peaking at about a million jobs per day. The system dynamically distributes popular data to expedite processing and maximally utilize resources. The reliability of the DA service is high but steadily improving; grid sites are continually validated against a set of standard tests, and a dedicated team of expert shifters ...

  18. The ATLAS Distributed Analysis System

    CERN Document Server

    Legger, F; The ATLAS collaboration


    In the LHC operations era, analysis of the multi-petabyte ATLAS data sample by globally distributed physicists is a challenging task. To attain the required scale the ATLAS Computing Model was designed around the concept of grid computing, realized in the Worldwide LHC Computing Grid (WLCG), the largest distributed computational resource existing in the sciences. The ATLAS experiment currently stores over 140 PB of data and runs about 140,000 concurrent jobs continuously at WLCG sites. During the first run of the LHC, the ATLAS Distributed Analysis (DA) service has operated stably and scaled as planned. More than 1600 users submitted jobs in 2012, with 2 million or more analysis jobs per week, peaking at about a million jobs per day. The system dynamically distributes popular data to expedite processing and maximally utilize resources. The reliability of the DA service is high but steadily improving; grid sites are continually validated against a set of standard tests, and a dedicated team of expert shifters ...

  19. IEA/SPS 500 kW distributed collector system (United States)

    Neumann, T. W.; Hartman, C. D.


    Engineering studies for an International Energy Agency project for the design and construction of a 500 kW solar thermal electric power generation system of the distributed collector system (DCS) type are reviewed. The DCS system design consists of a mixed field of parabolic trough type solar collectors which are used to heat a thermal heat transfer oil. Heated oil is delivered to a thermocline storage tank from which heat is extracted and delivered to a boiler by a second heat transfer loop using the same heat transfer oil. Steam is generated in the boiler, expanded through a steam turbine, and recirculated through a condenser system cooled by a wet cooling tower.

  20. Stand Alone Battery Thermal Management System

    Energy Technology Data Exchange (ETDEWEB)

    Brodie, Brad [Denso International America, Incorporated, Southfield, MI (United States)


    The objective of this project is research, development and demonstration of innovative thermal management concepts that reduce the cell or battery weight, complexity (component count) and/or cost by at least 20%. The project addresses two issues that are common problems with current state of the art lithium ion battery packs used in vehicles; low power at cold temperatures and reduced battery life when exposed to high temperatures. Typically, battery packs are “oversized” to satisfy the two issues mentioned above. The first phase of the project was spent making a battery pack simulation model using AMEsim software. The battery pack used as a benchmark was from the Fiat 500EV. FCA and NREL provided vehicle data and cell data that allowed an accurate model to be created that matched the electrical and thermal characteristics of the actual battery pack. The second phase involved using the battery model from the first phase and evaluate different thermal management concepts. In the end, a gas injection heat pump system was chosen as the dedicated thermal system to both heat and cool the battery pack. Based on the simulation model. The heat pump system could use 50% less energy to heat the battery pack in -20°C ambient conditions, and by keeping the battery cooler at hot climates, the battery pack size could be reduced by 5% and still meet the warranty requirements. During the final phase, the actual battery pack and heat pump system were installed in a test bench at DENSO to validate the simulation results. Also during this phase, the system was moved to NREL where testing was also done to validate the results. In conclusion, the heat pump system can improve “fuel economy” (for electric vehicle) by 12% average in cold climates. Also, the battery pack size, or capacity, could be reduced 5%, or if pack size is kept constant, the pack life could be increased by two years. Finally, the total battery pack and thermal system cost could be reduced 5% only if the

  1. Thermal Insulation System for Large Flame Buckets (United States)

    Callens, E. Eugene, Jr.; Gamblin, Tonya Pleshette


    The objective of this study is to investigate the use of thermal protection coatings, single tiles, and layered insulation systems to protect the walls of the flame buckets used in the testing of the Space Shuttle Main Engine, while reducing the cost and maintenance of the system. The physical behavior is modeled by a plane wall boundary value problem with a convective frontface condition and a backface condition designed to provide higher heat rates through the material.

  2. Distribution of thermal neutron flux around a PET cyclotron. (United States)

    Ogata, Yoshimune; Ishigure, Nobuhito; Mochizuki, Shingo; Ito, Kengo; Hatano, Kentaro; Abe, Junichiro; Miyahara, Hiroshi; Masumoto, Kazuyoshi; Nakamura, Hajime


    The number of positron emission tomography (PET) examinations has greatly increased world-wide. Since positron emission nuclides for the PET examinations have short half-lives, they are mainly produced using on-site cyclotrons. During the production of the nuclides, significant quantities of neutrons are generated from the cyclotrons. Neutrons have potential to activate the materials around the cyclotrons and cause exposure to the staff. To investigate quantities and distribution of the thermal neutrons, thermal neutron fluxes were measured around a PET cyclotron in a laboratory associating with a hospital. The cyclotron accelerates protons up to 18 MeV, and the mean particle current is 20 μA. The neutron fluxes were measured during both 18F production and C production. Gold foils and thermoluminescent dosimeter (TLD) badges were used to measure the neutron fluxes. The neutron fluxes in the target box averaged 9.3 × 10(6) cm(-2) s(-1) and 1.7 × 10(6) cm(-2) s(-1) during 18F and 11C production, respectively. Those in the cyclotron room averaged 4.1 × 10(5) cm(-2) s(-1) and 1.2 × 10(5) cm(-2) s(-1), respectively. Those outside the concrete wall shielding were estimated as being equal to or less than ∼3 cm s, which corresponded to 0.1 μSv h(-1) in effective dose. The neutron fluxes outside the concrete shielding were confirmed to be quite low compared to the legal limit.

  3. Distributed optimal coordination for distributed energy resources in power systems

    DEFF Research Database (Denmark)

    Wu, Di; Yang, Tao; Stoorvogel, A.


    Driven by smart grid technologies, distributed energy resources (DERs) have been rapidly developing in recent years for improving reliability and efficiency of distribution systems. Emerging DERs require effective and efficient coordination in order to reap their potential benefits. In this paper......, we consider an optimal DER coordination problem over multiple time periods subject to constraints at both system and device levels. Fully distributed algorithms are proposed to dynamically and automatically coordinate distributed generators with multiple/single storages. With the proposed algorithms...

  4. Thermal Performance Testing of Cryogenic Insulation Systems (United States)

    Fesmire, James E.; Augustynowicz, Stan D.; Scholtens, Brekke E.


    Efficient methods for characterizing thermal performance of materials under cryogenic and vacuum conditions have been developed. These methods provide thermal conductivity data on materials under actual-use conditions and are complementary to established methods. The actual-use environment of full temperature difference in combination with vacuum-pressure is essential for understanding insulation system performance. Test articles include solids, foams, powders, layered blankets, composite panels, and other materials. Test methodology and apparatus design for several insulation test cryostats are discussed. The measurement principle is liquid nitrogen boil-off calorimetry. Heat flux capability ranges from approximately 0.5 to 500 watts per square meter; corresponding apparent thermal conductivity values range from below 0.01 up to about 60 mW/m- K. Example data for different insulation materials are also presented. Upon further standardization work, these patented insulation test cryostats can be available to industry for a wide range of practical applications.

  5. Thermal diffusivity measurement system applied to polymers (United States)

    Abad, B.; Díaz-Chao, P.; Almarza, A.; Amantia, D.; Vázquez-Campos, S.; Isoda, Y.; Shinohara, Y.; Briones, F.; Martín-González, M. S.


    In the search for cleaner energy sources, the improvement of the efficiency of the actual ones appears as a primary objective. In this way, thermoelectric materials, which are able to convert wasted heat into electricity, are reveal as an interesting way to improve efficiency of car engines, for example. Cost-effective energy harvesting from thermoelectric devices requires materials with high electrical conductivities and Seebeck coefficient, but low thermal conductivity. Conductive polymers can fulfil these conditions if they are doped appropriately. One of the most promising polymers is Polyaniline. In this work, the thermal conductivity of the polyaniline and mixtures of polyaniline with nanoclays has been studied, using a new experimental set-up developed in the lab. The novel system is based on the steady-state method and it is used to obtain the thermal diffusivity of the polymers and the nanocomposites.

  6. Distributed antenna system and method (United States)

    Fink, Patrick W. (Inventor); Dobbins, Justin A. (Inventor)


    System and methods are disclosed for employing one or more radiators having non-unique phase centers mounted to a body with respect to a plurality of transmitters to determine location characteristics of the body such as the position and/or attitude of the body. The one or more radiators may consist of a single, continuous element or of two or more discrete radiation elements whose received signals are combined. In a preferred embodiment, the location characteristics are determined using carrier phase measurements whereby phase center information may be determined or estimated. A distributed antenna having a wide angle view may be mounted to a moveable body in accord with the present invention. The distributed antenna may be utilized for maintaining signal contact with multiple spaced apart transmitters, such as a GPS constellation, as the body rotates without the need for RF switches to thereby provide continuous attitude and position determination of the body.

  7. Thermal Propulsion Capture System Heat Exchanger Design (United States)

    Richard, Evan M.


    One of the biggest challenges of manned spaceflight beyond low earth orbit and the moon is harmful radiation that astronauts would be exposed to on their long journey to Mars and further destinations. Using nuclear energy has the potential to be a more effective means of propulsion compared to traditional chemical engines (higher specific impulse). An upper stage nuclear engine would allow astronauts to reach their destination faster and more fuel efficiently. Testing these engines poses engineering challenges due to the need to totally capture the engine exhaust. The Thermal Propulsion Capture System is a concept for cost effectively and safely testing Nuclear Thermal Engines. Nominally, hydrogen exhausted from the engine is not radioactive, but is treated as such in case of fuel element failure. The Thermal Propulsion Capture System involves injecting liquid oxygen to convert the hydrogen exhaust into steam. The steam is then cooled and condensed into liquid water to allow for storage. The Thermal Propulsion Capture System concept for ground testing of a nuclear powered engine involves capturing the engine exhaust to be cooled and condensed before being stored. The hydrogen exhaust is injected with liquid oxygen and burned to form steam. That steam must be cooled to saturation temperatures before being condensed into liquid water. A crossflow heat exchanger using water as a working fluid will be designed to accomplish this goal. Design a cross flow heat exchanger for the Thermal Propulsion Capture System testing which: Eliminates the need for water injection cooling, Cools steam from 5800 F to saturation temperature, and Is efficient and minimizes water requirement.

  8. Advaced Spatio-Temporal Thermal Analysis of Electronic Systems

    Directory of Open Access Journals (Sweden)

    Miroslav Hrianka


    Full Text Available The article gives a brief review the of diagnostics and analysis possibilities by a spatio-temporal approach into electronic system in infrared bandwidth. The two dimensional image grabbed by the thermo vision camera provides information about the surface temperature distribution of an electronic system. The main idea is based on the analysis of the object which consists of a temporal sequence of a spatial thermal images. Advanced analysis is achieved by morphological image gradient spatio-temporal model: The mentioned method provides a total temperature system evaluation as well as it allows separate analysis in the chosen determined temperature area.

  9. Advanced Rigid Ablative Thermal Protection Systems (United States)

    Feldman, J. D.; Gasch, M. J.; Poteet, C. C.; Szalai, Christine


    With the gradual increase in robotic rover sophistication and the desire for humans to explore the solar system, the need for reentry systems to deliver large payloads into planetary atmospheres is looming. Heritage ablative Thermal Protection Systems (TPS) using Viking or Pathfinder era materials are at or near their performance limits and will be inadequate for many future missions. Significant advances in TPS materials technology are needed in order to enable susequent human exploration missions. This paper summarizes some recent progress at NASA in developing families of advanced rigid ablative TPS that could be used for thermal protection in planetary entry missions. In particular, the effort focuses on technologies required to land heavy masses on Mars to facilitate exploration.

  10. 14 CFR 29.1355 - Distribution system. (United States)


    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Distribution system. 29.1355 Section 29.1355 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Distribution system. (a) The distribution system includes the distribution busses, their associated feeders...

  11. 14 CFR 25.1355 - Distribution system. (United States)


    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Distribution system. 25.1355 Section 25.1355 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Distribution system. (a) The distribution system includes the distribution busses, their associated feeders...

  12. Video distribution system cost model (United States)

    Gershkoff, I.; Haspert, J. K.; Morgenstern, B.


    A cost model that can be used to systematically identify the costs of procuring and operating satellite linked communications systems is described. The user defines a network configuration by specifying the location of each participating site, the interconnection requirements, and the transmission paths available for the uplink (studio to satellite), downlink (satellite to audience), and voice talkback (between audience and studio) segments of the network. The model uses this information to calculate the least expensive signal distribution path for each participating site. Cost estimates are broken downy by capital, installation, lease, operations and maintenance. The design of the model permits flexibility in specifying network and cost structure.

  13. Distribution System Voltage Regulation by Distributed Energy Resources

    Energy Technology Data Exchange (ETDEWEB)

    Ceylan, Oguzhan [ORNL; Liu, Guodong [ORNL; Xu, Yan [ORNL; Tomsovic, Kevin [University of Tennessee, Knoxville (UTK)


    This paper proposes a control method to regulate voltages in 3 phase unbalanced electrical distribution systems. A constrained optimization problem to minimize voltage deviations and maximize distributed energy resource (DER) active power output is solved by harmony search algorithm. IEEE 13 Bus Distribution Test System was modified to test three different cases: a) only voltage regulator controlled system b) only DER controlled system and c) both voltage regulator and DER controlled system. The simulation results show that systems with both voltage regulators and DER control provide better voltage profile.

  14. User Registration Systems for Distributed Systems (United States)

    Murphy, K. J.; Cechini, M.; Pilone, D.; Mitchell, A.


    As NASA’s Earth Observing System Data and Information System (EOSDIS) systems have evolved over the years, most of the EOSDIS data are now available to users via anonymous on-line access. Although the changes have improved the dissemination efficiency of earth science data, the anonymous access has made it difficult to characterize users, capture metrics on the value of EOSDIS and provide customized services that benefit users. As the number of web-based applications continues to grow, data centers and application providers have implemented their own user registration systems and provided new tools and interfaces for their registered users. This has led to the creation of independent registration systems for accessing data and interacting with online tools and services. The user profile information maintained at each of these registration systems is not consistent and the registration enforcement varies by system as well. This problem is in no way unique to EOSDIS and represents a general challenge to the distributed computing community. In a study done in 2007(, the average user has approximately 7 passwords for about 25 accounts and enters a password 8 times a day. These numbers have only increased in the last three years. To try and address this, a number of solutions have been offered including Single Sign-On solutions using a common backend like Microsoft Active Directory or an LDAP server, trust based identity providers like OpenID, and various forms of authorization delegation like OAuth or SAML/XACML. This talk discusses the differences between authentication and authorization, the state of the more popular user registration solutions available for distributed use, and some of the technical and policy drivers that need to be considered when incorporating a user registration system into your application.


    Directory of Open Access Journals (Sweden)

    Davood Domairry Ganji


    Full Text Available In this paper, homotopy perturbation method has been used to evaluate the temperature distribution of annular fin with temperature-dependent thermal conductivity and to determine the temperature distribution within the fin. This method is useful and practical for solving the nonlinear heat transfer equation, which is associated with variable thermal conductivity condition. The homotopy perturbation method provides an approximate analytical solution in the form of an infinite power series. The annular fin heat transfer rate with temperature-dependent thermal conductivity has been obtained as a function of thermo-geometric fin parameter and the thermal conductivity parameter describing the variation of the thermal conductivity.

  16. Laser thermal shock and fatigue testing system (United States)

    Fantini, Vincenzo; Serri, Laura; Bianchi, P.


    Thermal fatigue consists in repeatedly cycling the temperature of a specimen under test without any other constraint and stopping the test when predefined damage aspects. The result is a lifetime in terms of number of cycles. The parameters of the thermal cycle are the following: minimum and maximum temperature, time of heating, of cooling and time at high or at low temperature. When the temperature jump is very big and fast, phenomena of thermal shock can be induced. Among the numerous techniques used to perform these tests, the laser thermal fatigue cycling is very effective when fast heating of small and localized zones is required. That's the case of test performed to compare new and repaired blades of turbogas machines or components of combustion chambers of energy power plants. In order to perform these tests a thermal fatigue system, based on 1 kW Nd-YAG laser as source of heating, has been developed. The diameter of the heated zone of the specimen irradiated by the laser is in the range 0.5 - 20 mm. The temperatures can be chosen between 200 degree(s)C and 1500 degree(s)C and the piece can be maintained at high and/or low temperature from 0 s to 300 s. Temperature are measured by two sensors: a pyrometer for the high range (550 - 1500 degree(s)C) and a contactless thermocouple for the low range (200 - 550 degree(s)C). Two different gases can be blown on the specimen in the irradiated spot or in sample backside to speed up cooling phase. A PC-based control unit with a specially developed software performs PID control of the temperature cycle by fast laser power modulation. A high resolution vision system of suitable magnification is connected to the control unit to detect surface damages on the specimen, allowing real time monitoring of the tested zone as well as recording and reviewing the images of the sample during the test. Preliminary thermal fatigue tests on flat specimens of INCONEL 738 and HAYNES 230 are presented. IN738 samples, laser cladded by

  17. Thermalization and Pseudolocality in Extended Quantum Systems (United States)

    Doyon, Benjamin


    Recently, it was understood that modified concepts of locality played an important role in the study of extended quantum systems out of equilibrium, in particular in so-called generalized Gibbs ensembles. In this paper, we rigorously study pseudolocal charges and their involvement in time evolutions and in the thermalization process of arbitrary states with strong enough clustering properties. We show that the densities of pseudolocal charges form a Hilbert space, with inner product determined by thermodynamic susceptibilities. Using this, we define the family of pseudolocal states, which are determined by pseudolocal charges. This family includes thermal Gibbs states at high enough temperatures, as well as (a precise definition of) generalized Gibbs ensembles. We prove that the family of pseudolocal states is preserved by finite time evolution, and that, under certain conditions, the stationary state emerging at infinite time is a generalized Gibbs ensemble with respect to the evolution dynamics. If the evolution dynamics does not admit any conserved pseudolocal charges other than the evolution Hamiltonian, we show that any stationary pseudolocal state with respect to these dynamics is a thermal Gibbs state, and that Gibbs thermalization occurs. The framework is that of translation-invariant states on hypercubic quantum lattices of any dimensionality (including quantum chains) and finite-range Hamiltonians, and does not involve integrability.

  18. Loss Allocation in a Distribution System with Distributed Generation Units

    DEFF Research Database (Denmark)

    Lund, Torsten; Nielsen, Arne Hejde; Sørensen, Poul Ejnar


    In Denmark, a large part of the electricity is produced by wind turbines and combined heat and power plants (CHPs). Most of them are connected to the network through distribution systems. This paper presents a new algorithm for allocation of the losses in a distribution system with distributed...... generation. The algorithm is based on a reduced impedance matrix of the network and current injections from loads and production units. With the algorithm, the effect of the covariance between production and consumption can be evaluated. To verify the theoretical results, a model of the distribution system...

  19. Comparative evaluation of distributed-collector solar thermal electric power plants (United States)

    Fujita, T.; El Gabalawi, N.; Herrera, G. G.; Caputo, R. S.


    Distributed-collector solar thermal-electric power plants are compared by projecting power plant economics of selected systems to the 1990-2000 timeframe. The approach taken is to evaluate the performance of the selected systems under the same weather conditions. Capital and operational costs are estimated for each system. Energy costs are calculated for different plant sizes based on the plant performance and the corresponding capital and maintenance costs. Optimum systems are then determined as the systems with the minimum energy costs for a given load factor. The optimum system is comprised of the best combination of subsystems which give the minimum energy cost for every plant size. Sensitivity analysis is done around the optimum point for various plant parameters.

  20. Web Services / Distributed Systems : Can Web Services Be Used as Foundation for Distributed Systems?


    Skaaden, Solvor Jenny Brodtkorb


    This thesis analyse distributed systems and web services to see if web services can be used as a foundation for distributed systems. The thesis looks at the theoretical and practical aspects of both distributed systems and web services. The thesis is divided into four parts: Distributed systems, web services, web services development and evaluation. Distributed systems Distributed systems have been a part of computer science for decades. They are systems where different components in a...

  1. Novel Battery Management System with Distributed Wireless and Fiber Optic Sensors for Early Detection and Suppression of Thermal Runaway in Large Battery Packs, FY13 Q4 Report, ARPA-E Program: Advanced Management Protection of Energy Storage Devices (AMPE

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Chang, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Zumstein, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kovotsky, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Puglia, F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Dobley, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Moore, G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Osswald, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wolf, K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kaschmitter, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Eaves, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)


    Technology has been developed that enables monitoring of individual cells in highcapacity lithium-ion battery packs, with a distributed array of wireless Bluetooth 4.0 tags and sensors, and without proliferation of extensive wiring harnesses. Given the safety challenges facing lithium-ion batteries in electric vehicle, civilian aviation and defense applications, these wireless sensors may be particularly important to these emerging markets. These wireless sensors will enhance the performance, reliability and safety of such energy storage systems. Specific accomplishments to date include, but are not limited to: (1) the development of wireless tags using Bluetooth 4.0 standard to monitor a large array of sensors in battery pack; (2) sensor suites enabling the simultaneous monitoring of cell voltage, cell current, cell temperature, and package strain, indicative of swelling and increased internal pressure, (3) small receivers compatible with USB ports on portable computers; (4) software drivers and logging software; (5) a 7S2P battery simulator, enabling the safe development of wireless BMS hardware in the laboratory; (6) demonstrated data transmission out of metal enclosures, including battery box, with small variable aperture opening; (7) test data demonstrating the accurate and reliable operation of sensors, with transmission of terminal voltage, cell temperature and package strain at distances up to 110 feet; (8) quantification of the data transmission error as a function of distance, in both indoor and outdoor operation; (9) electromagnetic interference testing during operation with live, high-capacity battery management system at Yardney Technical Products; (10) demonstrated operation with live high-capacity lithium-ion battery pack during charge-discharge cycling; (11) development of special polymer-gel lithium-ion batteries with embedded temperature sensors, capable of measuring the core temperature of individual of the cells during charge-discharge cycling

  2. The Planetary Data System Distributed Inventory System (United States)

    Hughes, J. Steven; McMahon, Susan K.


    The advent of the World Wide Web (Web) and the ability to easily put data repositories on-line has resulted in a proliferation of digital libraries. The heterogeneity of the underlying systems, the autonomy of the individual sites, and distributed nature of the technology has made both interoperability across the sites and the search for resources within a site major research topics. This article will describe a system that addresses both issues using standard Web protocols and meta-data labels to implement an inventory of on-line resources across a group of sites. The success of this system is strongly dependent on the existence of and adherence to a standards architecture that guides the management of meta-data within participating sites.

  3. Energy Management of Smart Distribution Systems (United States)

    Ansari, Bananeh

    Electric power distribution systems interface the end-users of electricity with the power grid. Traditional distribution systems are operated in a centralized fashion with the distribution system owner or operator being the only decision maker. The management and control architecture of distribution systems needs to gradually transform to accommodate the emerging smart grid technologies, distributed energy resources, and active electricity end-users or prosumers. The content of this document concerns with developing multi-task multi-objective energy management schemes for: 1) commercial/large residential prosumers, and 2) distribution system operator of a smart distribution system. The first part of this document describes a method of distributed energy management of multiple commercial/ large residential prosumers. These prosumers not only consume electricity, but also generate electricity using their roof-top solar photovoltaics systems. When photovoltaics generation is larger than local consumption, excess electricity will be fed into the distribution system, creating a voltage rise along the feeder. Distribution system operator cannot tolerate a significant voltage rise. ES can help the prosumers manage their electricity exchanges with the distribution system such that minimal voltage fluctuation occurs. The proposed distributed energy management scheme sizes and schedules each prosumer's ES to reduce the electricity bill and mitigate voltage rise along the feeder. The second part of this document focuses on emergency energy management and resilience assessment of a distribution system. The developed emergency energy management system uses available resources and redundancy to restore the distribution system's functionality fully or partially. The success of the restoration maneuver depends on how resilient the distribution system is. Engineering resilience terminology is used to evaluate the resilience of distribution system. The proposed emergency energy

  4. Configuration of distributed message converter systems

    NARCIS (Netherlands)

    Risse, Thomas; Aberer, Karl; Wombacher, Andreas; Surridge, Mike; Taylor, Stephen


    Finding a configuration of a distributed system satisfying performance goals is a complex search problem that involves many design parameters, like hardware selection, job distribution and process configuration. Performance models are a powerful tool to analyze potential system configurations,

  5. Thermal Excitation System for Shearography (TESS) (United States)

    Lansing, Matthew D.; Bullock, Michael W.


    One of the most convenient and effective methods of stressing a part or structure for shearographic evaluation is thermal excitation. This technique involves heating the part, often convectively with a heat gun, and then monitoring with a shearography device the deformation during cooling. For a composite specimen, unbonds, delaminations, inclusions, or matrix cracking will deform during cooling differently than other more structurally sound regions and thus will appear as anomalies in the deformation field. However, one of the difficulties that cause this inspection to be dependent on the operator experience is the conventional heating process. Fanning the part with a heat gun by hand introduces a wide range of variability from person to person and from one inspection to the next. The goal of this research effort was to conduct research in the methods of thermal excitation for shearography inspection. A computerized heating system was developed for inspection of 0.61 m (24 in.) square panels. The Thermal Excitation System for Shearography (TESS) provides radiant heating with continuous digital measurement of the surface temperature profile to ensure repeatability. The TESS device functions as an accessory to any electronic shearography device.

  6. Light distribution system comprising spectral conversion means

    DEFF Research Database (Denmark)


    System (200, 300) for the distribution of white light, having a supply side (201, 301, 401) and a delivery side (202, 302, 402), the system being configured for guiding light with a multitude of visible wavelengths in a propagation direction P from the supply side to the distribution side, the sy...... of providing a light distribution system and a method of correcting the spectral transmission characteristics of a light distribution system are disclosed....

  7. Thermal Management for Dependable On-Chip Systems


    Ebi, Thomas


    This thesis addresses the dependability issues in on-chip systems from a thermal perspective. This includes an explanation and analysis of models to show the relationship between dependability and tempature. Additionally, multiple novel methods for on-chip thermal management are introduced aiming to optimize thermal properties. Analysis of the methods is done through simulation and through infrared thermal camera measurements.

  8. A distributed program composition system (United States)

    Brown, Robert L.


    A graphical technique for creating distributed computer programs is investigated and a prototype implementation is described which serves as a testbed for the concepts. The type of programs under examination is restricted to those comprising relatively heavyweight parts that intercommunicate by passing messages of typed objects. Such programs are often presented visually as a directed graph with computer program parts as the nodes and communication channels as the edges. This class of programs, called parts-based programs, is not well supported by existing computer systems; much manual work is required to describe the program to the system, establish the communication paths, accommodate the heterogeneity of data types, and to locate the parts of the program on the various systems involved. The work described solves most of these problems by providing an interface for describing parts-based programs in this class in a way that closely models the way programmers think about them: using sketches of diagraphs. Program parts, the computational modes of the larger program system are categorized in libraries and are accessed with browsers. The process of programming has the programmer draw the program graph interactively. Heterogeneity is automatically accommodated by the insertion of type translators where necessary between the parts. Many decisions are necessary in the creation of a comprehensive tool for interactive creation of programs in this class. Possibilities are explored and the issues behind such decisions are presented. An approach to program composition is described, not a carefully implemented programming environment. However, a prototype implementation is described that can demonstrate the ideas presented.

  9. Protection for DC Distribution System with Distributed Generator

    Directory of Open Access Journals (Sweden)

    Shimin Xue


    Full Text Available DC distribution system has advantages of high power quality, large transmission capacity, high reliability, simple structure, economy and low energy consumption, and so forth. It has been a key part of smart grid nowadays. However, the development of DC distribution system is constrained by the lack of operational experience in DC system, the small interrupting capacity of DC circuit breaker (CB, and the lack of protection schemes for system itself. In this paper, protection for DC distribution system with distributed generator (DG is fully investigated and verified. Firstly, the electromagnetic transient model of DC distribution system with DG is presented. Simulation based on the electromagnetic transient model is carried out. Both the step response and the steady-state performance verify the accuracy of the model. Then the fault characteristic mechanism is analyzed, and the protection principles and scheme are investigated in detail, including voltage mutation principle as protection starting component, differential current protection principle for DC bus, and two-section current protection for distribution lines. Finally, transient responses with protection scheme are analyzed during faults. The results present that the protection principles and scheme are feasible for DC distribution system with DG.

  10. Thermal Components Boost Performance of HVAC Systems (United States)


    As the International Space Station (ISS) travels 17,500 miles per hour, normal is having a constant sensation of free-falling. Normal is no rain, but an extreme amount of shine.with temperatures reaching 250 F when facing the Sun. Thanks to a number of advanced control systems onboard the ISS, however, the interior of the station remains a cool, comfortable, normal environment where astronauts can live and work for extended periods of time. There are two main control systems on the ISS that make it possible for humans to survive in space: the Thermal Control System (TCS) and the Environmental Control and Life Support system. These intricate assemblies work together to supply water and oxygen, regulate temperature and pressure, maintain air quality, and manage waste. Through artificial means, these systems create a habitable environment for the space station s crew. The TCS constantly works to regulate the temperature not only for astronauts, but for the critical instruments and machines inside the spacecraft as well. To do its job, the TCS encompasses several components and systems both inside and outside of the ISS. Inside the spacecraft, a liquid heat-exchange process mechanically pumps fluids in closed-loop circuits to collect, transport, and reject heat. Outside the ISS, an external system circulates anhydrous ammonia to transport heat and cool equipment, and radiators release the heat into space. Over the years, NASA has worked with a variety of partners.public and private, national and international. to develop and refine the most complex thermal control systems ever built for spacecraft, including the one on the ISS.

  11. System for Testing Thermal Insulation of Pipes (United States)

    Fesmire, James E.; Augustynowicz, Stanislaw D.; Nagy, Zoltan F.


    An apparatus and method have been developed for measuring the rates of leakage of heat into pipes carrying liquids, the purpose of the measurements being to quantify the thermal performance of the insulation system. The apparatus is designed primarily for testing pipes used to carry cryogenic liquids, but can also be used for measuring the thermal performance of other insulated pipes or piping systems. The basic measurement principle is straightforward: The outer surface of the pipe insulation is maintained at a fixed warmer temperature. The interior of the pipe is maintained in a narrow fixed lower-temperature range by means of a regular liquid (e.g., water) that is pumped through the pipe at a known flow rate or a cryogenic liquid (e.g., nitrogen) that is saturated at atmospheric pressure and replenished until steady-state conditions are achieved. In the case of water or another liquid pumped through, the inlet and outlet temperatures are measured and heat-leak power is calculated as the mass flow rate of the liquid multiplied by the specific heat of the liquid multiplied by the inlet-to-outlet temperature rise of the liquid. In the case of liquid nitrogen or another low-temperature boiling liquid, the heat-leak power is calculated as the rate of boil-off multiplied by the latent heat of vaporization of the liquid. Then the thermal-insulation performance of the pipe system can be calculated as a function of the measured heat-leak power, the inner and outer boundary temperatures, and the dimensions of the pipe. The apparatus can test as many as three pipes simultaneously. The pipes can have inner diameters up to .15 cm and outer diameters up to .20 cm. The lengths of the pipes may vary; typical lengths are of the order of 18 m. Two thermal guard boxes . one for each end of the pipe(s) under test . are used to make the inlet and outlet fluid connections to the pipe(s) (see figure). The connections include bellows that accommodate thermal expansion and contraction

  12. Protection of Active Distribution Systems with DGs (United States)

    Akila, Abdelrahman Ahmed; Helal, Ahmed; Eldesouki, Hussein


    Distribution systems are traditionally designed as radial passive systems fed from a single source. Protection coordination of such systems has been easily established assuming the system radiality. Insertion of distributed generators (DGs) into distribution systems makes the distribution system to be more active which causes redistribution of fault currents magnitudes and directions. This causes negative impacts on the original protection system coordination, since the distribution system losses its radiality and passiveness. Recently protection coordination in the presence of distributed generation has been paid a great attention. Researchers proposed various solutions to solve the protection coordination problem caused by adding DG into the distribution network. In this paper, the proposed solutions for the protection coordination problem considering the DG insertion will be illustrated, classified, and criticized.

  13. Aerogel Beads as Cryogenic Thermal Insulation System (United States)

    Fesmire, J. E.; Augustynowicz, S. D.; Rouanet, S.; Thompson, Karen (Technical Monitor)


    An investigation of the use of aerogel beads as thermal insulation for cryogenic applications was conducted at the Cryogenics Test Laboratory of NASA Kennedy Space Center. Steady-state liquid nitrogen boiloff methods were used to characterize the thermal performance of aerogel beads in comparison with conventional insulation products such as perlite powder and multilayer insulation (MLI). Aerogel beads produced by Cabot Corporation have a bulk density below 100 kilograms per cubic meter (kg/cubic m) and a mean particle diameter of 1 millimeter (mm). The apparent thermal conductivity values of the bulk material have been determined under steady-state conditions at boundary temperatures of approximately 293 and 77 kelvin (K) and at various cold vacuum pressures (CVP). Vacuum levels ranged from 10(exp -5) torr to 760 torr. All test articles were made in a cylindrical configuration with a typical insulation thickness of 25 mm. Temperature profiles through the thickness of the test specimens were also measured. The results showed the performance of the aerogel beads was significantly better than the conventional materials in both soft-vacuum (1 to 10 torr) and no-vacuum (760 torr) ranges. Opacified aerogel beads performed better than perlite powder under high-vacuum conditions. Further studies for material optimization and system application are in progress.

  14. The Impact of Connecting Distributed Generation to the Distribution System

    Directory of Open Access Journals (Sweden)

    E. V. Mgaya


    Full Text Available This paper deals with the general problem of utilizing of renewable energy sources to generate electric energy. Recent advances in renewable energy power generation technologies, e.g., wind and photovoltaic (PV technologies, have led to increased interest in the application of these generation devices as distributed generation (DG units. This paper presents the results of an investigation into possible improvements in the system voltage profile and reduction of system losses when adding wind power DG (wind-DG to a distribution system. Simulation results are given for a case study, and these show that properly sized wind DGs, placed at carefully selected sites near key distribution substations, could be very effective in improving the distribution system voltage profile and reducing power losses, and hence could  improve the effective capacity of the system

  15. Thermal modelling of normal distributed nanoparticles through thickness in an inorganic material matrix (United States)

    Latré, S.; Desplentere, F.; De Pooter, S.; Seveno, D.


    Nanoscale materials showing superior thermal properties have raised the interest of the building industry. By adding these materials to conventional construction materials, it is possible to decrease the total thermal conductivity by almost one order of magnitude. This conductivity is mainly influenced by the dispersion quality within the matrix material. At the industrial scale, the main challenge is to control this dispersion to reduce or even eliminate thermal bridges. This allows to reach an industrially relevant process to balance out the high material cost and their superior thermal insulation properties. Therefore, a methodology is required to measure and describe these nanoscale distributions within the inorganic matrix material. These distributions are either random or normally distributed through thickness within the matrix material. We show that the influence of these distributions is meaningful and modifies the thermal conductivity of the building material. Hence, this strategy will generate a thermal model allowing to predict the thermal behavior of the nanoscale particles and their distributions. This thermal model will be validated by the hot wire technique. For the moment, a good correlation is found between the numerical results and experimental data for a randomly distributed form of nanoparticles in all directions.

  16. Wind Power in Electrical Distribution Systems

    DEFF Research Database (Denmark)

    Chen, Zhe


    Recent years, wind power is experiencing a rapid growth, large number of wind turbines/wind farms have been installed and connected to power systems. In addition to the large centralised wind farms connected to transmission grids, many distributed wind turbines and wind farms are operated...... as distributed generators in distribution systems. This paper discusses the issues of wind turbines in distribution systems. Wind power conversion systems briefly introduced, the basic features and technical characteristics of distributed wind power system are described, and the main technical demands...

  17. LARGO hot water system thermal performance test report (United States)


    The thermal performance tests and results on the LARGO Solar Hot Water System under natural environmental conditions is presented. Some objectives of these evaluations are to determine the amount of energy collected, the amount of energy delivered to the household as contributed by solar power supplied to operate the system and auxiliary power to maintain tank temperature at proper level, overall system efficiency and to determine temperature distribution within the tank. The Solar Hot Water system is termed a Dump-type because of the draining system for freeze protection. The solar collector is a single glazed flat plate. An 82-gallon domestic water heater is provided as the energy storage vessel. Water is circulated through the collector and water heater by a 5.3 GPM capacity pump, and control of the pump motor is achieved by a differential temperature controller.

  18. Final design of thermal diagnostic system in SPIDER ion source

    Energy Technology Data Exchange (ETDEWEB)

    Brombin, M., E-mail:; Dalla Palma, M.; Pasqualotto, R.; Pomaro, N. [Consorzio RFX, Corso Stati Uniti 4, I-35127 Padova (Italy)


    The prototype radio frequency source of the ITER heating neutral beams will be first tested in SPIDER test facility to optimize H{sup −} production, cesium dynamics, and overall plasma characteristics. Several diagnostics will allow to fully characterise the beam in terms of uniformity and divergence and the source, besides supporting a safe and controlled operation. In particular, thermal measurements will be used for beam monitoring and system protection. SPIDER will be instrumented with mineral insulated cable thermocouples, both on the grids, on other components of the beam source, and on the rear side of the beam dump water cooled elements. This paper deals with the final design and the technical specification of the thermal sensor diagnostic for SPIDER. In particular the layout of the diagnostic, together with the sensors distribution in the different components, the cables routing and the conditioning and acquisition cubicles are described.

  19. Final design of thermal diagnostic system in SPIDER ion source (United States)

    Brombin, M.; Dalla Palma, M.; Pasqualotto, R.; Pomaro, N.


    The prototype radio frequency source of the ITER heating neutral beams will be first tested in SPIDER test facility to optimize H- production, cesium dynamics, and overall plasma characteristics. Several diagnostics will allow to fully characterise the beam in terms of uniformity and divergence and the source, besides supporting a safe and controlled operation. In particular, thermal measurements will be used for beam monitoring and system protection. SPIDER will be instrumented with mineral insulated cable thermocouples, both on the grids, on other components of the beam source, and on the rear side of the beam dump water cooled elements. This paper deals with the final design and the technical specification of the thermal sensor diagnostic for SPIDER. In particular the layout of the diagnostic, together with the sensors distribution in the different components, the cables routing and the conditioning and acquisition cubicles are described.

  20. Thermally activated, single component epoxy systems

    KAUST Repository

    Unruh, David A.


    A single component epoxy system in which the resin and hardener components found in many two-component epoxies are combined onto the same molecule is described. The single molecule precursor to the epoxy resin contains both multiple epoxide moieties and a diamine held latent by thermally degradable carbamate linkages. These bis-carbamate "single molecule epoxies" have an essentially infinite shelf life and access a significant range in curing temperatures related to the structure of the carbamate linkages used. © 2011 American Chemical Society.

  1. Deployment Mechanism for Thermal Pointing System (United States)

    Koski, Kraig


    The Deployment Mechanism for the Total and Spectral Solar Irradiance Sensor (TSIS) is responsible for bringing the Thermal Pointing System (TPS) from its stowed, launch locked position to the on-orbit deployed, operational position. The Deployment Mechanism also provides structural support for the TSIS optical bench and two-axis gimbal. An engineering model of the Deployment Mechanism has been environmentally qualified and life tested. This paper will give an overview of the TSIS mission and then describe the development, design, and testing of the Deployment Mechanism.

  2. Investigation on the Interface Characteristics of the Thermal Barrier Coating System through Flat Cylindrical Indenters

    Directory of Open Access Journals (Sweden)

    Shifeng Wen


    Full Text Available Thermal barrier coating (TBC systems are highly advanced material systems and usually applied to insulate components from large and prolonged heat loads by utilizing thermally insulating materials. In this study, the characteristics of the interface of thermal barrier coating systems have been simulated by the finite-element method (FEM. The emphasis was put on the stress distribution at the interface which is beneath the indenter. The effect of the interface roughness, the thermally grown oxide (TGO layer's thickness, and the modulus ratio (η of the thin film with the substrate has been considered. Finite-element results showed that the influences of the interface roughness and the TGO layer's thickness on stress distribution were important. At the same time, the residual stress distribution has been investigated in detail.

  3. Low jitter RF distribution system (United States)

    Wilcox, Russell; Doolittle, Lawrence; Huang, Gang


    A timing signal distribution system includes an optical frequency stabilized laser signal amplitude modulated at an rf frequency. A transmitter box transmits a first portion of the laser signal and receive a modified optical signal, and outputs a second portion of the laser signal and a portion of the modified optical signal. A first optical fiber carries the first laser signal portion and the modified optical signal, and a second optical fiber carries the second portion of the laser signal and the returned modified optical signal. A receiver box receives the first laser signal portion, shifts the frequency of the first laser signal portion outputs the modified optical signal, and outputs an electrical signal on the basis of the laser signal. A detector at the end of the second optical fiber outputs a signal based on the modified optical signal. An optical delay sensing circuit outputs a data signal based on the detected modified optical signal. An rf phase detect and correct signal circuit outputs a signal corresponding to a phase stabilized rf signal based on the data signal and the frequency received from the receiver box.

  4. 49 CFR 179.18 - Thermal protection systems. (United States)


    ..., underframes, metal jackets, insulation, and thermal protection. A complete record of each analysis shall be...) Systems that no longer require test verification. The Department maintains a list of thermal protection... 49 Transportation 2 2010-10-01 2010-10-01 false Thermal protection systems. 179.18 Section 179.18...

  5. Protection of Distribution Systems with Distributed Energy Resources

    DEFF Research Database (Denmark)

    Bak-Jensen, Birgitte; Browne, Matthew; Calone, Roberto

    of 17 months of work of the Joint Working Group B5/C6.26/CIRED “Protection of Distribution Systems with Distributed Energy Resources”. The working group used the CIGRE report TB421 “The impact of Renewable Energy Sources and Distributed Generation on Substation Protection and Automation”, published...... are listed (chapter 3). The first main part of the report starts with a summary of the backgrounds on DER and current practices in protection at the distribution level (chapter 4). This chapter contains an analysis of CIGRE TB421, protection relevant characteristics of DER, a review of current practices...

  6. Toward the Universal DC Distribution System

    NARCIS (Netherlands)

    Mackay, L.J.; van der Blij, N.H.; Ramirez Elizondo, L.M.; Bauer, P.


    AbstractDue to an increasing number of power generation units and load devices operating with direct current (DC) at distribution level, there is a potential benefit of leading efforts toward building a DC distribution system. However, the implementation of DC distribution systems faces important


    Directory of Open Access Journals (Sweden)

    Popescu V.S.


    Full Text Available Power distribution systems are basic parts of power systems and reliability of these systems at present is a key issue for power engineering development and requires special attention. Operation of distribution systems is accompanied by a number of factors that produce random data a large number of unplanned interruptions. Research has shown that the predominant factors that have a significant influence on the reliability of distribution systems are: weather conditions (39.7%, defects in equipment(25% and unknown random factors (20.1%. In the article is studied the influence of random behavior and are presented estimations of reliability of predominantly rural electrical distribution systems.

  8. An Automatic System to Detect Thermal Leakages and Damages on Building Facade Using Thermal Images


    Sirmacek, Beril; Hoegner, Ludwig; Stilla, Uwe


    In recent years, very high energy consumption is the major problem of the big cities. Most of the energy of the cities are disbursed to warm and cool buildings. Thus, detecting heat leakages on building walls is a new research problem. In this study, we propose a novel system to detect thermal leakages automatically from thermal camera images. To this end, we use sequential thermal images of buildings. First, we start with fusing thermal image sequences to obtain rectified building facade wit...

  9. Review on Islanding Operation of Distribution System with Distributed Generation

    DEFF Research Database (Denmark)

    Mahat, Pukar; Chen, Zhe; Bak-Jensen, Birgitte


    The growing environmental concern and various benefits of distributed generation (DG) have resulted in significant penetration of DG in many distribution systems worldwide. One of the major expected benefits of DG is the improvement in the reliability of power supply by supplying load during power...... outage by operating in an island mode. However, there are many challenges to overcome before islanding operation of a distribution system with DG can become a viable solution in future. This paper reviews some of the major challenges with islanding operation and explores some possible solutions...

  10. Applying Prolog to Develop Distributed Systems



    Development of distributed systems is a difficult task. Declarative programming techniques hold a promising potential for effectively supporting programmer in this challenge. While Datalog-based languages have been actively explored for programming distributed systems, Prolog received relatively little attention in this application area so far. In this paper we present a Prolog-based programming system, called DAHL, for the declarative development of distributed systems. DAHL extends Prolog w...

  11. 3D Multifunctional Ablative Thermal Protection System (United States)

    Feldman, Jay; Venkatapathy, Ethiraj; Wilkinson, Curt; Mercer, Ken


    NASA is developing the Orion spacecraft to carry astronauts farther into the solar system than ever before, with human exploration of Mars as its ultimate goal. One of the technologies required to enable this advanced, Apollo-shaped capsule is a 3-dimensional quartz fiber composite for the vehicle's compression pad. During its mission, the compression pad serves first as a structural component and later as an ablative heat shield, partially consumed on Earth re-entry. This presentation will summarize the development of a new 3D quartz cyanate ester composite material, 3-Dimensional Multifunctional Ablative Thermal Protection System (3D-MAT), designed to meet the mission requirements for the Orion compression pad. Manufacturing development, aerothermal (arc-jet) testing, structural performance, and the overall status of material development for the 2018 EM-1 flight test will be discussed.

  12. Numerical Modeling of a Shallow Borehole Thermal Energy Storage System (United States)

    Catolico, N.; Ge, S.; Lu, N.; McCartney, J. S.


    Borehole thermal energy storage (BTES) combined with solar thermal energy harvesting is an economic technological system to garner and store energy as well as an environmentally-sustainable alternative for the heating of buildings. The first community-scale BTES system in North America was installed in 2007 in the Drake Landing Solar Community (DLSC), about 35 miles south of Calgary, Canada. The BTES system involves direct circulation of water heated from solar thermal panels in the summer into a storage tank, after which it is circulate within an array of 144 closed-loop geothermal heat exchangers having a depth of 35 m and a spacing of 2.5 m. In the winter the circulation direction is reversed to supply heat to houses. Data collection over a six year period indicates that this system can supply more than 90% of the winter heating energy needs for 52 houses in the community. One major challenge facing the BTES system technology is the relatively low annual efficiency, i.e., the ratio of energy input and output is in the range of 15% to 40% for the system in Drake Landing. To better understand the working principles of BTES and to improve BTES performance for future applications at larger scales, a three-dimensional transient coupled fluid and heat transfer model is established using TOUGH2. The time-dependent injection temperatures and circulation rate measured over the six years of monitoring are used as model input. The simulations are calibrated using soil temperature data measured at different locations over time. The time-dependent temperature distributions within the borehole region agree well with the measured temperatures for soil with an intrinsic permeability of 10e-19 m2, an apparent thermal conductivity of 2.03 W/m°C, and a volumetric heat capacity of 2.31 MJ/m-3°C. The calibrated model serves as the basis for a sensitivity analysis of soil and operational parameters on BTES system efficiency preformed with TOUGH2. Preliminary results suggest 1) BTES

  13. Declarative testing and depolyment of distributed systems

    NARCIS (Netherlands)

    Van der Burg, S.; Dolstra, E.


    System administrators and developers who deploy distributed systems have to deal with a deployment process that is largely manual and hard to reproduce. This paper describes how networks of computer systems can be reproducibly and automatically deployed from declarative specifications.

  14. Simulation of Thermal Distribution and Airflow for Efficient Energy Consumption in a Small Data Centers

    Directory of Open Access Journals (Sweden)

    Jing Ni


    Full Text Available Data centers have become ubiquitous in the last few years in an attempt to keep pace with the processing and storage needs of the Internet and cloud computing. The steady growth in the heat densities of IT servers leads to a rise in the energy needed to cool them, and constitutes approximately 40% of the power consumed by data centers. However, many data centers feature redundant air conditioning systems that contribute to inefficient air distribution, which significantly increases energy consumption. This remains an insufficiently explored problem. In this paper, a typical, small data center with tiles for an air supply system with a raised floor is used. We use a fluent (Computational Fluid Dynamics, CFD to simulate thermal distribution and airflow, and investigate the optimal conditions of air distribution to save energy. The effects of the airflow outlet angle along the tile, the cooling temperature and the rate of airflow on the beta index as well as the energy utilization index are discussed, and the optimal conditions are obtained. The reasonable airflow distribution achieved using 3D CFD calculations and the parameter settings provided in this paper can help reduce the energy consumption of data centers by improving the efficiency of the air conditioning.

  15. Temperature Distribution and Thermal Deformation of the Crystallization Roller Based on the Direct Thermal-Structural Coupling Method (United States)

    Pan, Liping; He, Zhu; Li, Baokuan; Zhou, Kun; Sun, Ke


    The temperature distribution and the thermal deformation of the crystallization roller have a significant effect on the forming process of the thin steel strip. Finite element analysis has been used to simulate the temperature distribution and the thermal deformation in a crystallization roller through the direct thermal-structural coupling analysis method. Various parameters, such as different rotational velocities, diverse locations of cooling water pipes, and typical velocities of cooling water have been systematically investigated. It is found that the temperature and the equivalent stress of the outer surface reach the steady state after 30 s of rotations, and they are influenced remarkably by the factors of rotational velocity and cooling water pipe depth. Meanwhile, the radial displacement approaches the steady state after 300 s of revolutions and is significantly affected by the cooling water velocity.

  16. The Thermal Plume above a Standing Human Body Exposed to Different Air Distribution Strategies

    DEFF Research Database (Denmark)

    Liu, Li; Nielsen, Peter V.; Li, Yuguo


    This study compares the impact of air distribution on the thermal plume above a human body in indoor environment. Three sets of measurements are conducted in a full-scale test room with different ventilation conditions. One breathing thermal manikin standing in the room is used to simulate...... the human body. Long-time average air velocity profiles at locations closely above the manikin are taken to identify the wandering thermal plume....

  17. Nutrients and heavy metal distribution in thermally treated pig manure

    DEFF Research Database (Denmark)

    Kuligowski, Ksawery; Poulsen, Tjalfe G.; Stoholm, Peder


    Ash from pig manure treated by combustion and thermal gasification was characterized and compared in terms of nutrient, i.e., potassium (K), phosphorus (P) and heavy metal, i.e., cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni) and zinc (Zn) contents. Total nutrient and metal concentrations...

  18. Worldwide distribution of soil dielectric and thermal properties

    NARCIS (Netherlands)

    Hendrickx, J.M.H.; Dam, R.L. van; Borchers, B.; Curtis, J.; Lensen, H.A.; Harmon, R.


    Ground penetrating radar and thermal sensors hold much promise for the detection of non-metallic land mines. In previous work we have shown that the performance of ground penetrating radar strongly depends on field soil conditions such as texture, water content, and soil-water salinity since these

  19. Investigation of effective factors of transient thermal stress of the MONJU-System components

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Masaaki; Hirayama, Hiroshi; Kimura, Kimitaka; Jinbo, M. [Toshiba Corp., Kawasaki, Kanagawa (Japan)


    Transient thermal stress of each system Component in the fast breeder reactor is an uncertain factor on it's structural design. The temperature distribution in a system component changes over a wide range in time and in space. An unified evaluation technique of thermal, hydraulic, and structural analysis, in which includes thermal striping, temperature stratification, transient thermal stress and the integrity of the system components, is required for the optimum design of tho fast reactor plant. Thermal boundary conditions should be set up by both the transient thermal stress analysis and the structural integrity evaluation of each system component. The reasonable thermal boundary conditions for the design of the MONJU and a demonstration fast reactor, are investigated. The temperature distribution analysis models and the thermal boundary conditions on the Y-piece structural parts of each system component, such as reactor vessel, intermediate heat exchanger, primary main circulation pump, steam generator, superheater and upper structure of reactor core, are illustrated in the report. (M. Suetake)

  20. Integrated Thermal Insulation System for Spacecraft (United States)

    Kolodziej, Paul (Inventor); Bull, Jeff (Inventor); Kowalski, Thomas (Inventor); Switzer, Matthew (Inventor)


    An integrated thermal protection system (TPS) for a spacecraft includes a grid that is bonded to skin of the spacecraft, e.g., to support the structural loads of the spacecraft. A plurality of thermally insulative, relatively large panels are positioned on the grid to cover the skin of the spacecraft to which the grid has been bonded. Each panel includes a rounded front edge and a front flange depending downwardly from the front edge. Also, each panel includes a rear edge formed with a rounded socket for receiving the rounded front edge of another panel therein, and a respective rear flange depends downwardly from each rear edge. Pins are formed on the front flanges, and pin receptacles are formed on the rear flanges, such that the pins of a panel mechanically interlock with the receptacles of the immediately forward panel. To reduce the transfer to the skin of heat which happens to leak through the panels to the grid, the grid includes stringers that are chair-shaped in cross-section.

  1. Intelligent Engine Systems: Thermal Management and Advanced Cooling (United States)

    Bergholz, Robert


    The objective of the Advanced Turbine Cooling and Thermal Management program is to develop intelligent control and distribution methods for turbine cooling, while achieving a reduction in total cooling flow and assuring acceptable turbine component safety and reliability. The program also will develop embedded sensor technologies and cooling system models for real-time engine diagnostics and health management. Both active and passive control strategies will be investigated that include the capability of intelligent modulation of flow quantities, pressures, and temperatures both within the supply system and at the turbine component level. Thermal management system concepts were studied, with a goal of reducing HPT blade cooling air supply temperature. An assessment will be made of the use of this air by the active clearance control system as well. Turbine component cooling designs incorporating advanced, high-effectiveness cooling features, will be evaluated. Turbine cooling flow control concepts will be studied at the cooling system level and the component level. Specific cooling features or sub-elements of an advanced HPT blade cooling design will be downselected for core fabrication and casting demonstrations.

  2. A Survey on Distributed File System Technology (United States)

    Blomer, J.


    Distributed file systems provide a fundamental abstraction to location-transparent, permanent storage. They allow distributed processes to co-operate on hierarchically organized data beyond the life-time of each individual process. The great power of the file system interface lies in the fact that applications do not need to be modified in order to use distributed storage. On the other hand, the general and simple file system interface makes it notoriously difficult for a distributed file system to perform well under a variety of different workloads. This has lead to today's landscape with a number of popular distributed file systems, each tailored to a specific use case. Early distributed file systems merely execute file system calls on a remote server, which limits scalability and resilience to failures. Such limitations have been greatly reduced by modern techniques such as distributed hash tables, content-addressable storage, distributed consensus algorithms, or erasure codes. In the light of upcoming scientific data volumes at the exabyte scale, two trends are emerging. First, the previously monolithic design of distributed file systems is decomposed into services that independently provide a hierarchical namespace, data access, and distributed coordination. Secondly, the segregation of storage and computing resources yields to a storage architecture in which every compute node also participates in providing persistent storage.

  3. Examination and characterization of distribution system biofilms.


    LeChevallier, M W; Babcock, T M; Lee, R G


    Investigations concerning the role of distribution system biofilms on water quality were conducted at a drinking water utility in New Jersey. The utility experienced long-term bacteriological problems in the distribution system, while treatment plant effluents were uniformly negative for coliform bacteria. Results of a monitoring program showed increased coliform levels as the water moved from the treatment plant through the distribution system. Increased coliform densities could not be accou...

  4. Intelligent Systems for Power Management and Distribution (United States)

    Button, Robert M.


    The motivation behind an advanced technology program to develop intelligent power management and distribution (PMAD) systems is described. The program concentrates on developing digital control and distributed processing algorithms for PMAD components and systems to improve their size, weight, efficiency, and reliability. Specific areas of research in developing intelligent DC-DC converters and distributed switchgear are described. Results from recent development efforts are presented along with expected future benefits to the overall PMAD system performance.

  5. Thermal properties of composite materials: a complex systems approximation (United States)

    Carrillo, J. L.; Bonilla, Beatriz; Reyes, J. J.; Dossetti, Victor

    We propose an effective media approximation to describe the thermal diffusivity of composite samples made of polyester resin and magnetite inclusions. By means of photoacoustic spectroscopy, the thermal diffusivity of the samples were experimentally measured. The volume fraction of the inclusions was systematically varied in order to study the changes in the effective thermal diffusivity of the composites. For some samples, a static magnetic field was applied during the polymerization process, resulting in anisotropic inclusion distributions. Our results show a significant difference in the thermal properties of the anisotropic samples, compared to the isotropic randomly distributed. We correlate some measures of the complexity of the inclusion structure with the observed thermal response through a multifractal analysis. In this way, we are able to describe, and at some extent predict, the behavior of the thermal diffusivity in terms of the lacunarity and other measures of the complexity of these samples Partial Financial Support by CONACyT México and VIEP-BUAP.

  6. The analysis of thermal network of district heating system from investor point of view (United States)

    Takács, Ján; Rácz, Lukáš


    The hydraulics of a thermal network of a district heating system is a very important issue, to which not enough attention is often paid. In this paper the authors want to point out some of the important aspects of the design and operation of thermal networks in district heating systems. The design boundary conditions of a heat distribution network and the requirements on active pressure - circulation pump - influencing the operation costs of the centralized district heating system as a whole, are analyzed in detail. The heat generators and the heat exchange stations are designed according to the design heat loads after thermal insulation, and modern boiler units are installed in the heating plant.

  7. Islanding Operation of Distribution System with Distributed Generations

    DEFF Research Database (Denmark)

    Mahat, Pukar; Chen, Zhe; Bak-Jensen, Birgitte


    The growing interest in distributed generations (DGs) due to environmental concern and various other reasons have resulted in significant penetration of DGs in many distribution system worldwide. DGs come with many benefits. One of the benefits is improved reliability by supplying load during pow...... outage by operating in island mode. However, there are many challenges to overcome before islanding can become a viable solution in future. This paper point outs some of the major challenges with island operation and suggests some possible solutions.......The growing interest in distributed generations (DGs) due to environmental concern and various other reasons have resulted in significant penetration of DGs in many distribution system worldwide. DGs come with many benefits. One of the benefits is improved reliability by supplying load during power...

  8. Distributed computer systems theory and practice

    CERN Document Server

    Zedan, H S M


    Distributed Computer Systems: Theory and Practice is a collection of papers dealing with the design and implementation of operating systems, including distributed systems, such as the amoeba system, argus, Andrew, and grapevine. One paper discusses the concepts and notations for concurrent programming, particularly language notation used in computer programming, synchronization methods, and also compares three classes of languages. Another paper explains load balancing or load redistribution to improve system performance, namely, static balancing and adaptive load balancing. For program effici

  9. Automatic Thermal Control System with Temperature Difference or Derivation Feedback

    Directory of Open Access Journals (Sweden)

    Darina Matiskova


    Full Text Available Automatic thermal control systems seem to be non-linear systems with thermal inertias and time delay. A controller is also non-linear because its information and power signals are limited. The application of methods that are available to on-linear systems together with computer simulation and mathematical modelling creates a possibility to acquire important information about the researched system. This paper provides a new look at the heated system model and also designs the structure of the thermal system with temperature derivation feedback. The designed system was simulated by using a special software in Turbo Pascal. Time responses of this system are compared to responses of a conventional thermal system. The thermal system with temperature derivation feedback provides better transients, better quality of regulation and better dynamical properties.

  10. Work Distribution in a Fully Distributed Processing System. (United States)


    system throughput. Most reseachers and system designers would agree that these two goals are very important, but there seems to be no consensus as to...graph theoretic approach when applied to fully distributed systems is the inability of the algorithm to account for the impact of queueing delays on...Bozzetti, M., and Ravasio, P.C. Internetting among local and long haul networks: A case study. Proceedings of the Fifth International Conference on

  11. Research Issues in Distributed Operating Systems

    NARCIS (Netherlands)

    Tanenbaum, A.S.; van Renesse, R.; Hertzberger, L.O.; Hoogland, W.


    As distributed computing becomes more widespread, both in high-energy physics and in other applications, centralized operating systems will gradually give way to distributed ones. In this paper the authors discuss some current research on five issues that are central to the design of distributed

  12. Online Scheduling in Distributed Message Converter Systems

    NARCIS (Netherlands)

    Risse, Thomas; Wombacher, Andreas; Surridge, Mike; Taylor, Steve; Aberer, Karl

    The optimal distribution of jobs among hosts in distributed environments is an important factor to achieve high performance. The optimal strategy depends on the application. In this paper we present a new online scheduling strategy for distributed EDI converter system. The strategy is based on the

  13. Control and operation of distributed generation in distribution systems

    DEFF Research Database (Denmark)

    Mahat, Pukar; Chen, Zhe; Bak-Jensen, Birgitte


    algorithm, which uses average rate of change off requency (Af5) and real power shift RPS), in the islanded mode. RPS will increase or decrease the power set point of the generator with increasing or decreasing system frequency, respectively. Simulation results show that the proposed method can operate......Many distribution systems nowadays have significant penetration of distributed generation (DG)and thus, islanding operation of these distribution systems is becoming a viable option for economical and technical reasons. The DG should operate optimally during both grid-connected and island...... conditions, which can be achieved with change in operating strategy. Many islanding detection techniques have been developed but little work has been done to detect grid re-connection. This paper presents strategies to operate DG in grid connected and islanded modes and a new grid re-connection detection...

  14. Mathematical Modeling and Numerical Analysis of Thermal Distribution in Arch Dams considering Solar Radiation Effect (United States)

    Mirzabozorg, H.; Hariri-Ardebili, M. A.; Shirkhan, M.; Seyed-Kolbadi, S. M.


    The effect of solar radiation on thermal distribution in thin high arch dams is investigated. The differential equation governing thermal behavior of mass concrete in three-dimensional space is solved applying appropriate boundary conditions. Solar radiation is implemented considering the dam face direction relative to the sun, the slop relative to horizon, the region cloud cover, and the surrounding topography. It has been observed that solar radiation changes the surface temperature drastically and leads to nonuniform temperature distribution. Solar radiation effects should be considered in thermal transient analysis of thin arch dams. PMID:24695817

  15. Distributed Impact Detector System (DIDS) Health Monitoring System Evaluation (United States)

    Prosser, William H.; Madaras, Eric I.


    Damage due to impacts from micrometeoroids and orbital debris is one of the most significant on-orbit hazards for spacecraft. Impacts to thermal protection systems must be detected and the damage evaluated to determine if repairs are needed to allow safe re-entry. To address this issue for the International Space Station Program, Langley Research Center and Johnson Space Center technologists have been working to develop and implement advanced methods for detecting impacts and resultant leaks. LaRC funded a Small Business Innovative Research contract to Invocon, Inc. to develop special wireless sensor systems that are compact, light weight, and have long battery lifetimes to enable applications to long duration space structures. These sensor systems are known as distributed impact detection systems (DIDS). In an assessment, the NASA Engineering and Safety Center procured two prototype DIDS sensor units to evaluate their capabilities in laboratory testing and field testing in an ISS Node 1 structural test article. This document contains the findings of the assessment.

  16. Electric co-heating in the ASHRAE standard method of test for thermal distribution efficiency: Test results on two New York State homes

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, J.W.; Krajewski, R.F.; Strasser, J.J.


    Electric co-heating tests on two single-family homes with forced-air heating systems were carried out in March 1995. The goal of these tests was to evaluate procedures being considered for incorporation in a Standard Method of Test for thermal distribution system efficiency now being developed by ASHRAE. Thermal distribution systems are the ductwork, piping, or other means used to transport heat or cooling effect from the building equipment that produces this thermal energy to the spaces in which it is used. Furthering the project goal, the first objective of the tests was to evaluate electric co-heating as a means of measuring system efficiency. The second objective was to investigate procedures for obtaining the distribution efficiency, using system efficiency as a base. Distribution efficiencies of 0.63 and 0.70 were obtained for the two houses.

  17. Design of Distributed Voting Systems


    Meter, Christian


    Countries like Estonia, Norway or Australia developed electronic voting systems, which could be used to realize parliamentary elections with the help of personal computers and the Internet. These systems are completely different in their design and their way to solve the same problem. In this thesis, we analyze some of the largest real-world systems, describe their building blocks and their general design to focus on possible problems in these electronic voting systems. Furthermore, we presen...

  18. Novel Material Systems and Methodologies for Transient Thermal Management (United States)

    Oliva-Buisson, Yvette J.


    Development of multifunctional and thermally switchable systems to address reduced mass and components, and tailored for both structural and transient thermal applications. Active, passive, and novel combinations of the two functional approaches are being developed along two lines of research investigation: switchable systems and transient heat spreading. The approach is to build in thermal functionality to structural elements to lay the foundation for a revolution in the way high energy space systems are designed.

  19. Models and analysis for distributed systems

    CERN Document Server

    Haddad, Serge; Pautet, Laurent; Petrucci, Laure


    Nowadays, distributed systems are increasingly present, for public software applications as well as critical systems. software applications as well as critical systems. This title and Distributed Systems: Design and Algorithms - from the same editors - introduce the underlying concepts, the associated design techniques and the related security issues.The objective of this book is to describe the state of the art of the formal methods for the analysis of distributed systems. Numerous issues remain open and are the topics of major research projects. One current research trend consists of pro

  20. Internet and redefining tourism distribution system

    Directory of Open Access Journals (Sweden)

    Đelić Tanja


    Full Text Available Since the introduction, computerized systems that manage reservation systems, rapidly became inevitable distribution channel for all service companies in tourist industry. GDS in reality using communication network connects service offer, selling personnel and air companies.

  1. The three dimensional laser induced temperature distribution in photo-thermal displacement spectroscopy

    CERN Document Server

    Soltanolkotabi, M


    In this paper we present a detailed theoretical treatment of 3-D temperature distribution induced by laser beam in photothermal displacement spectroscopy. We assume that a solid sample, which is deposited on a substrate and is in contact with a fluid, is irradiated by an intensity modulated cw laser source. By using a technique based on Green's function and integral transformations we find the explicit expression for temperature distribution function. This function which depends on the properties of the laser beam and optical and thermal properties of the sample, the substrate and the fluid, exhibits the characteristics of a damped thermal wave. Numerical analysis of the temperature distribution for a certain sample (GaAs) reveals that the behavior of thermal wave is not so sensitive with respect to the variation of the modulation frequency. On the other hand, we find that the temperature of the sample surface decreases with increasing modulation frequency because of the thermal inter tia of the sample. Furth...

  2. The Conductive Thermal Control Material Systems for Space Applications Project (United States)

    National Aeronautics and Space Administration — This proposal is submitted to develop and demonstrate the feasibility of processing the space environment stable, multifunctional thermal control material system...

  3. Modeling elements of energy systems for thermal energy transportation

    Directory of Open Access Journals (Sweden)

    Shurygin A. M.


    Full Text Available Heating industrial facilities and the residential sector in recent years is the economic and technical challenge. It has been noted that the efficiency of the heat generating equipment depends not only on its sophistication, fuel type, but also on work of the distributing network taking into account the thermal, hydraulic losses, characteristics and modes of use of heating objects – buildings and technological processes. Possibility of supplying maximum heat flow from the heating system considering mismatch of highs and types of resources consumed from individual consumers should be provided by the right choice of energy equipment set, as well as bandwidth of transport systems and possibility of its regulation. It is important not just to configure the system to work effectively in the current mode (usually at the maximum load, but in the entire load range, as the calculated mode often takes a relatively small portion of the operating time. Thus, the efficiency of heating systems is largely determined by the method used for its control, including the possibility of regulating the main units and elements of the system. The paper considers the factors affecting the system efficiency. Mathematical models of the system elements allowing adjust the amount of released heat energy for consumers have been presented. Separately the mathematical model of the control system of electric drive vehicles used in the system has been considered and implemented.

  4. Thermal Noise Can Facilitate Energy Conversion by Ratchet System?


    Takagi, Fumiko; Hondou, Tsuyoshi


    Molecular motors in biological systems are expected to use ambient fluctuation. In a recent Letter [Phys. Rev. Lett. {\\bf 80}, 5251 (1998)], it was showed that the following question was unsolved, ``Can thermal noise facilitate energy conversion by ratchet system?'' We consider it using stochastic energetics, and show that there exist systems where thermal noise helps the energy conversion.

  5. Ceramic-Fibrous-Insulation Thermal-Protection System (United States)

    Leiser, Daniel; Churchward, Rex; Katvala, Victor; Stewart, David; Balter, Aliza


    New composite thermal-protection system developed in which glass-ceramic impregnated into surface of fibrous insulation. Called TUFI for toughened unipiece fibrous insulation developed as replacement for tiles with reaction-cured-glass (RCG) coating. Impregnation of glass-ceramic results in thermal protection system with insulating properties comparable to existing system but with 20 to 100 times more resistance to impact.

  6. Silver disinfection in water distribution systems (United States)

    Silvestry Rodriguez, Nadia

    Silver was evaluated as disinfectant to maintain water quality in water distribution system. It was used to inhibit growth of two opportunistic bacteria in planktonik form and in biofilm formation in Robbins devices with stainless steel and PVC surfaces. The results of this work show that silver is a potential secondary disinfectant to be used in water distribution systems.

  7. Decentralized Control of Scheduling in Distributed Systems. (United States)


    and Experience, 7,1, January 1977, 3-35. [WITT80] Wittie, L., and Andre M. Van Tilborg, "MICROS, A Distributed Operating System for Micronet , A...Andre M. van Tilborg, "MICROS, A Distributed Operating System for Micronet , A Reconfigurable Network Computer, = TCanaa.ion 2n Coinuters," Vol. C-29

  8. Hybrid solar lighting distribution systems and components (United States)

    Muhs, Jeffrey D [Lenoir City, TN; Earl, Dennis D [Knoxville, TN; Beshears, David L [Knoxville, TN; Maxey, Lonnie C [Powell, TN; Jordan, John K [Oak Ridge, TN; Lind, Randall F [Lenoir City, TN


    A hybrid solar lighting distribution system and components having at least one hybrid solar concentrator, at least one fiber receiver, at least one hybrid luminaire, and a light distribution system operably connected to each hybrid solar concentrator and each hybrid luminaire. A controller operates all components.

  9. Economic Models and Algorithms for Distributed Systems

    CERN Document Server

    Neumann, Dirk; Altmann, Jorn; Rana, Omer F


    Distributed computing models for sharing resources such as Grids, Peer-to-Peer systems, or voluntary computing are becoming increasingly popular. This book intends to discover fresh avenues of research and amendments to existing technologies, aiming at the successful deployment of commercial distributed systems

  10. Conductive thermal modeling of Wyoming geothermal systems

    Energy Technology Data Exchange (ETDEWEB)

    Heasler, H.P.; Ruscetta, C.A.; Foley, D. (eds.)


    A summary of techniques used by the Wyoming Geothermal Resource Assessment Group in defining low-temperature hydrothermal resource areas is presented. Emphasis is placed on thermal modeling techniques appropriate to Wyoming's geologic setting. Thermal parameters discussed include oil-well bottom hole temperatures, heat flow, thermal conductivity, and measured temperature-depth profiles. Examples of the use of these techniques are from the regional study of the Bighorn Basin and two site specific studies within the Basin.

  11. A Unique Electrical Thermal Stimulation System Comparable to Moxibustion of Subcutaneous Tissue

    Directory of Open Access Journals (Sweden)

    Hyoun-Seok Myoung


    Full Text Available Moxibustion strengthens immunity and it is an effective treatment modality, but, depending on the material quantity, shape, and composition, the thermal strength and intensity can be difficult to control, which may cause pain or epidermal burns. To overcome these limitations, a heat stimulating system which is able to control the thermal intensity was developed. The temperature distributions on epidermis, at 5 mm and 10 mm of depth, in rabbit femoral tissue were compared between moxibustion and the electric thermal stimulation system. The stimulation system consists of a high radio frequency dielectric heating equipment (2 MHz frequency, maximum power 200 W, isolation probe, isolation plate, negative pressure generator, and a temperature assessment system. The temperature was modulated by controlling the stimulation pulse duty ratio, repetition number, and output. There were 95% and 91% temperature distribution correlations between moxibustion and the thermal stimulus at 5 mm and 10 mm of depth in tissue, respectively. Moreover, the epidermal temperature in thermal stimulation was lower than that in moxibustion. These results showed that heat loss by the electric thermal stimulation system is less than that by the traditional moxibustion method. Furthermore, the proposed electric thermal stimulation did not cause adverse effects, such as suppuration or blisters, and also provided subcutaneous stimulation comparable to moxibustion.

  12. Thermistor-based thermal conductivity measurement system

    National Research Council Canada - National Science Library

    Atkins, R.T; Wright, E.A


    This report describes a patented method for using commercially available thermistors to make in-situ thermal conductivity measurements with commonly available electronic equipment such as digital voltmeters...

  13. Finite element analysis of thermal stress distribution in different ...

    African Journals Online (AJOL)

    stress distribution at the interface between the tooth surface and the restorative material has been very limited. ... cavity of human maxillary left first molar teeth has not been reported in any previously published study. ... in medicine format and the data were input into the computer. Using the software Materialize' Interactive ...

  14. DAVRS: an architecture of distributed VR systems (United States)

    Gu, Qin; Liu, Yan; Sun, Jizhou


    An architecture of distributed virtual reality system is brought forward in this paper. It's based on a C/S system model, and employs a centralized-and-distributed data distribution model. This data distribution model can efficiently realize concurrency control, and easily ensure the data consistency. It also employs a four-layered structure based on Message Queue to accomplish the collaboration management. This structure is platform-independent and very flexible for further extending and upgrading. In this paper, we'll introduce the C/S system model and the centralized-and-distributed data distribution model, and then discuss in detail how the four-layered structure based on Message Queue realizes the collaboration management.

  15. Large scale network-centric distributed systems

    CERN Document Server

    Sarbazi-Azad, Hamid


    A highly accessible reference offering a broad range of topics and insights on large scale network-centric distributed systems Evolving from the fields of high-performance computing and networking, large scale network-centric distributed systems continues to grow as one of the most important topics in computing and communication and many interdisciplinary areas. Dealing with both wired and wireless networks, this book focuses on the design and performance issues of such systems. Large Scale Network-Centric Distributed Systems provides in-depth coverage ranging from ground-level hardware issu

  16. Electrical power systems for distributed generation

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, T.A.; Huval, S.J. [Stewart & Stevenson Services, Inc., Houston, TX (United States)


    {open_quotes}Distributed Generation{close_quotes} has become the {open_quotes}buzz{close_quotes} word of an electric utility industry facing deregulation. Many industrial facilities utilize equipment in distributed installations to serve the needs of a thermal host through the capture of exhaust energy in a heat recovery steam generator. The electrical power generated is then sold as a {open_quotes}side benefit{close_quotes} to the cost-effective supply of high quality thermal energy. Distributed generation is desirable for many different reasons, each with unique characteristics of the product. Many years of experience in the distributed generation market has helped Stewart & Stevenson to define a range of product features that are crucial to most any application. The following paper will highlight a few of these applications. The paper will also examine the range of products currently available and in development. Finally, we will survey the additional services offered by Stewart & Stevenson to meet the needs of a rapidly changing power generation industry.

  17. Thermal Aspects of Future Spacecraft Thermal Management Systems. (United States)


    Manangement Systems. 19 ABSTRACT ,Conljn., on rverse if nre,.,ov and identify by block num~ber) % T his reporL-p-r-fiftri 13 -addresses the conceptual design...s--nvestigati-o were to determine the capabilities of the phase change materials’ (PCMs) selected by the knowledge-based system. Tests were carried to...CONTENTS Page . I INTRODUCTION ... .......... . .... . . . . 1 II BACKGROUND . .. .. .. .. .. .. .. .. .. .. .. 6 A. PHASE CHANGE MATERIALS

  18. Differences Between Distributed and Parallel Systems

    Energy Technology Data Exchange (ETDEWEB)

    Brightwell, R.; Maccabe, A.B.; Rissen, R.


    Distributed systems have been studied for twenty years and are now coming into wider use as fast networks and powerful workstations become more readily available. In many respects a massively parallel computer resembles a network of workstations and it is tempting to port a distributed operating system to such a machine. However, there are significant differences between these two environments and a parallel operating system is needed to get the best performance out of a massively parallel system. This report characterizes the differences between distributed systems, networks of workstations, and massively parallel systems and analyzes the impact of these differences on operating system design. In the second part of the report, we introduce Puma, an operating system specifically developed for massively parallel systems. We describe Puma portals, the basic building blocks for message passing paradigms implemented on top of Puma, and show how the differences observed in the first part of the report have influenced the design and implementation of Puma.

  19. On deadlock detection in distributed systems (United States)

    Gligor, V. D.; Shattuck, S. H.


    A hierarchically organized and a distributed protocol for deadlock detection in distributed databases are presented in a previous study Menasce and Muntz (1979). In this paper, it is shown that the distributed protocol is incorrect, and possible remedies are presented. However, the distributed protocol remains impractical because 'condensations' of 'transaction-wait-for' graphs make graph updates difficult to perform. Delayed graph updates cause the occurrence of false deadlocks in this as well as in some other deadlock detection protocols for distributed systems. The performance degradation that results from false deadlocks depends on the characteristics of each protocol.

  20. Agents-based distributed processes control systems

    Directory of Open Access Journals (Sweden)

    Adrian Gligor


    Full Text Available Large industrial distributed systems have revealed a remarkable development in recent years. We may note an increase of their structural and functional complexity, at the same time with those on requirements side. These are some reasons why there are involvednumerous researches, energy and resources to solve problems related to these types of systems. The paper addresses the issue of industrial distributed systems with special attention being given to the distributed industrial processes control systems. A solution for a distributed process control system based on mobile intelligent agents is presented.The main objective of the proposed system is to provide an optimal solution in terms of costs, maintenance, reliability and flexibility. The paper focuses on requirements, architecture, functionality and advantages brought by the proposed solution.

  1. PFS: a distributed and customizable file system

    NARCIS (Netherlands)

    Bosch, H.G.P.; Mullender, Sape J.


    In this paper we present our ongoing work on the Pegasus File System (PFS), a distributed and customizable file system that can be used for off-line file system experiments and on-line file system storage. PFS is best described as an object-oriented component library from which either a true file

  2. Quantum quenches and thermalization in one-dimensional systems (United States)

    Rigol, Marcos


    We use quantum quenches to study the dynamics and thermalization of hardcore bosons and fermions in finite one-dimensional lattices. We perform exact diagonalizations and find that, far away from integrability, few-body observables thermalize. We then study the breakdown of thermalization as one approaches an integrable point. This is found to be a smooth process in which the predictions of standard statistical mechanics continuously worsen as the system moves toward integrability. We establish a direct connection between the presence or absence of thermalization and the validity or failure of the eigenstate thermalization hypothesis, respectively.ReferencesM. Rigol, Phys. Rev. Lett. 103, 100403 (2009); Phys. Rev. A 80, 053607 (2009).

  3. Breakdown of thermalization in finite one-dimensional systems. (United States)

    Rigol, Marcos


    We use quantum quenches to study the dynamics and thermalization of hard core bosons in finite one-dimensional lattices. We perform exact diagonalizations and find that, far away from integrability, few-body observables thermalize. We then study the breakdown of thermalization as one approaches an integrable point. This is found to be a smooth process in which the predictions of standard statistical mechanics continuously worsen as the system moves toward integrability. We establish a direct connection between the presence or absence of thermalization and the validity or failure of the eigenstate thermalization hypothesis, respectively.

  4. Development of an Analysis System for Low Voltage Distribution System (United States)

    Matsuda, Katsuhiro; Wada, Masaru; Hirano, Shinichiro; Hirai, Yoshihiro; Tsuboe, Yasuhiro; Watanabe, Masahiro; Furukawa, Toshiyuki

    In recent years, distributed resources such as photovoltaic power generation system or wind-turbine generator system are increased, therefore the distributed resources which connect to distribution networks are increased gradually. Under the situation there are several problems such as expansion of the voltage fluctuation, increase of the short circuit current, increase of harmonics phenomenon which we have to consider, and the problems make us difficult to examine the effect of interconnection and to design the distribution system. However, analysis support system to evaluate the influence to connect distributed resources to low voltage distribution system has not developed. Therefore We have developed the analysis system for low voltage for low voltage distribution systems. We can evaluate the influence of distributed resources accurately, examine the interconnection and design the configuration of distribution networks by using the analysis system. In this paper, the concept of the analysis system, the load flow method for unbalanced V-connection 3-phase 4-line distribution system and the calculation method for the connectable capacity of distributed resources. Outline of the man/machine interface and examples of calculation results for sample network are also described.

  5. Distributed-data imaging system

    Energy Technology Data Exchange (ETDEWEB)

    Tolmie, D.E.; Dornhoff, A.G.; DuBois, A.J.; Hodson, S.W.; Maestas, F.A.; Winkler, K.H.


    A group of eight Digital Equipment Corporation Alpha workstations is interconnected with ATM to form a cluster with supercomputer power. For output, each workstation drives a single tile on an 8-tile high- resolution frame buffer. A special purpose adapter is used to convert the workstation`s ATM format to the frame buffer`s HIPPI format. This paper discusses the rationale behind the workstation farm, and then describes the visualization output path in detail. To provide the system quickly, special emphasis was placed on making the design as simple as possible and using standard software protocols to drive and synchronize the display. The design choices are examined, and the resultant system is described.. Previously, a display could connect to a single computer; or a group of computers could drive a fragmented display, e.g., a video wall. Our system is unique in that it provides a high-quality desktop visualization display driven collectively by a group of workstations. A short video will be shown during the presentation to demonstrate the system capabilities.

  6. Experimental Verification of Modeled Thermal Distribution Produced by a Piston Source in Physiotherapy Ultrasound (United States)

    Lopez-Haro, S. A.; Leija, L.


    Objectives. To present a quantitative comparison of thermal patterns produced by the piston-in-a-baffle approach with those generated by a physiotherapy ultrasonic device and to show the dependency among thermal patterns and acoustic intensity distributions. Methods. The finite element (FE) method was used to model an ideal acoustic field and the produced thermal pattern to be compared with the experimental acoustic and temperature distributions produced by a real ultrasonic applicator. A thermal model using the measured acoustic profile as input is also presented for comparison. Temperature measurements were carried out with thermocouples inserted in muscle phantom. The insertion place of thermocouples was monitored with ultrasound imaging. Results. Modeled and measured thermal profiles were compared within the first 10 cm of depth. The ideal acoustic field did not adequately represent the measured field having different temperature profiles (errors 10% to 20%). Experimental field was concentrated near the transducer producing a region with higher temperatures, while the modeled ideal temperature was linearly distributed along the depth. The error was reduced to 7% when introducing the measured acoustic field as the input variable in the FE temperature modeling. Conclusions. Temperature distributions are strongly related to the acoustic field distributions. PMID:27999801

  7. Experimental Verification of Modeled Thermal Distribution Produced by a Piston Source in Physiotherapy Ultrasound

    Directory of Open Access Journals (Sweden)

    M. I. Gutierrez


    Full Text Available Objectives. To present a quantitative comparison of thermal patterns produced by the piston-in-a-baffle approach with those generated by a physiotherapy ultrasonic device and to show the dependency among thermal patterns and acoustic intensity distributions. Methods. The finite element (FE method was used to model an ideal acoustic field and the produced thermal pattern to be compared with the experimental acoustic and temperature distributions produced by a real ultrasonic applicator. A thermal model using the measured acoustic profile as input is also presented for comparison. Temperature measurements were carried out with thermocouples inserted in muscle phantom. The insertion place of thermocouples was monitored with ultrasound imaging. Results. Modeled and measured thermal profiles were compared within the first 10 cm of depth. The ideal acoustic field did not adequately represent the measured field having different temperature profiles (errors 10% to 20%. Experimental field was concentrated near the transducer producing a region with higher temperatures, while the modeled ideal temperature was linearly distributed along the depth. The error was reduced to 7% when introducing the measured acoustic field as the input variable in the FE temperature modeling. Conclusions. Temperature distributions are strongly related to the acoustic field distributions.

  8. How to measure thermal effects of personal cooling systems : Human, thermal manikin and human simulator study

    NARCIS (Netherlands)

    Bogerd, N.; Psikuta, A.; Daanen, H.A.M.; Rossi, R.M.


    Thermal effects, such as cooling power and thermophysiological responses initiated upon application of a personal cooling system, can be assessed with (i) humans, (ii) a thermal manikin and (iii) a thermophysiological human simulator. In order to compare these methods, a cooling shirt (mild cooling)


    DEFF Research Database (Denmark)

    Lynggaard, Per


    A majority of the research performed today explore artificial intelligence in smart homes by using a centralized approach where a smart home server performs the necessary calculations. This approach has some disadvantages that can be overcome by shifting focus to a distributed approach where...... the artificial intelligence system is implemented as distributed as agents running parts of the artificial intelligence system. This paper presents a distributed smart home architecture that distributes artificial intelligence in smart homes and discusses the pros and cons of such a concept. The presented...... distributed model is a layered model. Each layer offers a different complexity level of the embedded distributed artificial intelligence. At the lowest layer smart objects exists, they are small cheap embedded microcontroller based smart devices that are powered by batteries. The next layer contains a more...

  10. The role of Solar thermal in Future Energy Systems

    DEFF Research Database (Denmark)

    Mathiesen, Brian Vad; Hansen, Kenneth


    This report deals with solar thermal technologies and investigates possible roles for solar thermal in future energy systems for four national energy systems; Germany, Austria, Italy and Denmark. The project period started in January 2014 and finished by October 2017. This report is based...

  11. Economic feasibility of thermal energy storage systems

    Energy Technology Data Exchange (ETDEWEB)

    Habeebullah, B.A. [Faculty of Engineering, King Abdulaziz University, Jeddah (Saudi Arabia)


    This paper investigates the economic feasibility of both building an ice thermal storage and structure a time of rate tariff for the unique air conditioning (A/C) plant of the Grand Holy Mosque of Makkah, Saudi Arabia. The features of the building are unique where the air-conditioned 39,300 m{sup 2} zone is open to the atmosphere and the worshippers fully occupy the building five times a day, in addition hundreds of thousands of worshippers attend the blessed weekend's prayer at noontime, which escalates the peak electricity load. For economic analysis, the objective function is the daily electricity bill that includes the operation cost and the capital investment of the ice storage system. The operation cost is function of the energy imported for operating the plant in which the tariff structure, number of operating hours and the ambient temperature are parameters. The capital recovery factor is calculated for 10% interest rate and payback period of 10 years. Full and partial load storage scenarios are considered. The results showed that with the current fixed electricity rate (0.07 $/kWh), there is no gain in introducing ice storage systems for both storage schemes. Combining energy storage and an incentive time structured rate showed reasonable daily bill savings. For base tariff of 0.07 $/kWh during daytime operation and 0.016 $/kWh for off-peak period, savings were achieved for full load storage scenario. Different tariff structure is discussed and the break-even nighttime rate was determined (varies between 0.008 and 0.03 $/kWh). Partial load storage scenario showed to be unattractive where the savings for the base structured tariff was insignificant. (author)

  12. Integrating photovoltaics into utility distribution systems

    Energy Technology Data Exchange (ETDEWEB)

    Zaininger, H.W. [Zaininger Engineering Co., Inc., San Jose, CA (United States); Barnes, P.R. [Oak Ridge National Lab., TN (United States)


    Electric utility distribution system impacts associated with the integration of distributed photovoltaic (PV) energy sources vary from site to site and utility to utility. The objective of this paper is to examine several utility- and site-specific conditions which may affect economic viability of distributed PV applications to utility systems. Assessment methodology compatible with technical and economic assessment techniques employed by utility engineers and planners is employed to determine PV benefits for seven different utility systems. The seven case studies are performed using utility system characteristics and assumptions obtained from appropriate utility personnel. The resulting site-specific distributed PV benefits increase nonsite-specific generation system benefits available to central station PV plants as much as 46%, for one utility located in the Southwest.

  13. Advanced smartgrids for distribution system operators

    CERN Document Server

    Boillot, Marc


    The dynamic of the Energy Transition is engaged in many region of the World. This is a real challenge for electric systems and a paradigm shift for existing distribution networks. With the help of "advanced" smart technologies, the Distribution System Operators will have a central role to integrate massively renewable generation, electric vehicle and demand response programs. Many projects are on-going to develop and assess advanced smart grids solutions, with already some lessons learnt. In the end, the Smart Grid is a mean for Distribution System Operators to ensure the quality and the secu

  14. Fuzzy Approximate Model for Distributed Thermal Solar Collectors Control

    KAUST Repository

    Elmetennani, Shahrazed


    This paper deals with the problem of controlling concentrated solar collectors where the objective consists of making the outlet temperature of the collector tracking a desired reference. The performance of the novel approximate model based on fuzzy theory, which has been introduced by the authors in [1], is evaluated comparing to other methods in the literature. The proposed approximation is a low order state representation derived from the physical distributed model. It reproduces the temperature transfer dynamics through the collectors accurately and allows the simplification of the control design. Simulation results show interesting performance of the proposed controller.

  15. Resonance width distribution for open quantum systems


    Shchedrin, Gavriil; Zelevinsky, Vladimir


    Recent measurements of resonance widths for low-energy neutron scattering off heavy nuclei show large deviations from the standard Porter-Thomas distribution. We propose a new resonance width distribution based on the random matrix theory for an open quantum system. Two methods of derivation lead to a single analytical expression; in the limit of vanishing continuum coupling, we recover the Porter-Thomas distribution. The result depends on the ratio of typical widths $\\Gamma$ to the energy le...

  16. Development of an Integrated Distribution Management System

    Energy Technology Data Exchange (ETDEWEB)

    Schatz, Joe E.


    This final report details the components, functionality, costs, schedule and benefits of developing an Integrated Distribution Management System (IDMS) for power distribution system operation. The Distribution Automation (DA) and Supervisory Control and Data Acquisition (SCADA) systems used by electric power companies to manage the distribution of electric power to retail energy consumers are vital components of the Nation’s critical infrastructure. Providing electricity is an essential public service and a disruption in that service, if not quickly restored, could threaten the public safety and the Nation’s economic security. Our Nation’s economic prosperity and quality of life have long depended on the essential services that utilities provide; therefore, it is necessary to ensure that electric utilities are able to conduct their operations safely and efficiently. A fully integrated technology of applications is needed to link various remote sensing, communications and control devices with other information tools that help guide Power Distribution Operations personnel. A fully implemented IDMS will provide this, a seamlessly integrated set of applications to raise electric system operating intelligence. IDMS will enhance DA and SCADA through integration of applications such as Geographic Information Systems, Outage Management Systems, Switching Management and Analysis, Operator Training Simulator, and other Advanced Applications, including unbalanced load flow and fault isolation/service restoration. These apps are capable of utilizing and obtaining information from appropriately installed DER, and by integrating disparate systems, the Distribution Operators will benefit from advanced capabilities when analyzing, controlling and operating the electric system.

  17. Thermal performance of marketed SDHW systems under laboratory conditions

    DEFF Research Database (Denmark)

    Furbo, Simon; Andersen, Elsa; Fan, Jianhua

    A test facility for solar domestic hot water systems, SDHW systems was established at the Technical University of Denmark in 1992. During the period 1992-2012 21 marketed SDHW systems, 16 systems from Danish manufacturers and 5 systems from manufacturers from abroad, have been tested in the test ...... comfort, avoiding simple errors, using the low flow principle and heat stores with a high degree of thermal stratification and by using components with good thermal characteristics....... to the models were fitted in such a way, that the calculated thermal performance is in good agreement with the measured thermal performance, both for a typical winter period and for a typical summer period. In this way it is possible to use the simulation models to calculate the yearly thermal performance...

  18. High Temperature Fiberoptic Thermal Imaging System Project (United States)

    National Aeronautics and Space Administration — The proposed Phase 1 program will fabricate and demonstrate a small diameter single fiber endoscope that can perform high temperature thermal imaging in a jet engine...

  19. Distributed context-aware systems

    CERN Document Server

    Ferreira, Paulo


    Context-aware systems aim to deliver a rich user experience by taking into?account the current user context (location, time, activity, etc.), possibly?captured without his intervention. For example, cell phones are now able to?continuously update a user's location while, at the same time, users execute?an increasing amount of activities online, where their actions may be easily?captured (e.g. login in a web application) without user consent. In the last decade, this topic has seen numerous developments that demonstrate its relevance and usefulness. The?trend was accelerated with the widespread

  20. Distributed Systems and Web Technologies


    Daniela PIRVU; Ghencea, Adrian; Violeta GAUCAN


    The information system shall represent the support of the put on and of the simplification of rules and administrative procedures in order to ensure a broad and non-discriminatory public access to public services and also to reduce tariffs for these services, along with the operating costs and the personnel costs. IT&C market and the major brands have come up with new solutions and new architectures: SOA (Services Oriented Architecture), S+S or SaS (Software as Services) complex architectures...

  1. Cryogenic distribution system for the first cell

    Energy Technology Data Exchange (ETDEWEB)

    Brown, D P; Schneider, W J


    The ISABELLE refrigeration system utilizes compressed liquid helium to supply refrigeration to nearly 1100 superconducting bending and focusing magnets. These magnets steer the proton orbits of the accelerator and are arranged into two interlocking rings. The cryogenic distribution system that is used to transmit the helium cooling from the central refrigerator to the superconducting magnets makes up a substantial portion (34%) of the total heat load that the refrigerator must be capable of supplying. This piping system has been designed to minimize the heat input into the refrigeration system. The design and test results of the distribution system in use on the ISABELLE prototype, the first cell are described.

  2. Water distribution systems design optimisation using metaheuristics ...

    African Journals Online (AJOL)

    The topic of multi-objective water distribution systems (WDS) design optimisation using metaheuristics is investigated, comparing numerous modern metaheuristics, including several multi-objective evolutionary algorithms, an estimation of distribution algorithm and a recent hyperheuristic named AMALGAM (an evolutionary ...

  3. Programming Languages for Distributed Computing Systems

    NARCIS (Netherlands)

    Bal, H.E.; Steiner, J.G.; Tanenbaum, A.S.


    When distributed systems first appeared, they were programmed in traditional sequential languages, usually with the addition of a few library procedures for sending and receiving messages. As distributed applications became more commonplace and more sophisticated, this ad hoc approach became less

  4. A Debugging Tool for Distributed Systems

    NARCIS (Netherlands)

    Scholten, Johan; Posthuma, John; Posthuma, J.G.


    This paper describes parts of the design of a debugger for a distributed real-time multimedia system. Emphasis lies on the distributed aspect of debugging, which means that attention is paid to the external behaviour of the processes. This type of debugging is useful to find communication or

  5. Thermal barrier coating system having improved adhesion (United States)

    Bill, R. C.; Sovey, J. S. (Inventor)


    The adherence between a ceramic thermal barrier coating and a metal bond coating is improved by ion sputtering a ceramic film on the bond cost. A ceramic thermal barrier coating is then plasma-sprayed onto this primer film. This improves the integrity and strength of the interface between the plasma-sprayed ceramic layer and metallic bond coat which insures stronger adherence between the metal and the ceramic.

  6. Recent trends in solar thermal sorption cooling system technology

    Directory of Open Access Journals (Sweden)

    Khaled M Bataineh


    Full Text Available Solar thermal cooling is the best alternative solution to overcome the problems associated with using nonrenewable resources. There are several thermal cooling methods developed differing from each other according to the thermodynamic cycle and type of refrigerant used. Recent developments in absorption and adsorption solar cooling systems are presented. Summarized thermodynamic modeling for both absorption and adsorption solar cooling systems is given. Brief thermal analysis among the types of solar collectors is presented. System efficiencies and optimization analysis are presented. The influences of geometrical, system configurations, and physical parameters on the performance of solar thermal sorption cooling system are investigated. The basis for the design of absorption and adsorption solar cooling systems is provided. Several case studies in different climatic conditions are presented. Economic feasibility for both systems is discussed. Comparison between the absorption and adsorption solar cooling system is summarized.

  7. Thermal Management System for Long-Lived Venus Landers Project (United States)

    National Aeronautics and Space Administration — The overall program objective is to develop a high-temperature passive thermal management system for the Radioisotope Power Conversion system that energizes the...

  8. Integral Radiators for Next Generation Thermal Control Systems Project (United States)

    National Aeronautics and Space Administration — Integral radiators integrate the primary structural system and the thermal rejection system into a dual function subsystem allowing for reduced weight. The design of...

  9. Aerogel-Based Insulation for Industrial Steam Distribution Systems

    Energy Technology Data Exchange (ETDEWEB)

    John Williams


    Thermal losses in industrial steam distribution systems account for 977 trillion Btu/year in the US, more than 1% of total domestic energy consumption. Aspen Aerogels worked with Department of Energy’s Industrial Technologies Program to specify, develop, scale-up, demonstrate, and deliver Pyrogel XT®, an aerogel-based pipe insulation, to market to reduce energy losses in industrial steam systems. The product developed has become Aspen’s best selling flexible aerogel blanket insulation and has led to over 60 new jobs. Additionally, this product has delivered more than ~0.7 TBTU of domestic energy savings to date, and could produce annual energy savings of 149 TBTU by 2030. Pyrogel XT’s commercial success has been driven by it’s 2-4X better thermal performance, improved durability, greater resistance to corrosion under insulation (CUI), and faster installation times than incumbent insulation materials.


    National Research Council Canada - National Science Library

    Lamp, John W; Fisher, Julie


    ... – and from commercial and open access publishers. This paper investigates the distribution of information systems journals over the various ERA parameters and comments on a claim of bias whereby the ranking of a journal is positively influenced...

  11. Overview of Distributed Control Systems Formalisms

    Directory of Open Access Journals (Sweden)

    Peter Holecko


    Full Text Available This paper discusses a chosen set of mainly object-oriented formal and semiformal methods, methodics, environments and tools for specification, analysis, modeling, simulation, verification, development and synthesis of distributed control systems (DCS.

  12. Mechanical properties of thermal protection system materials.

    Energy Technology Data Exchange (ETDEWEB)

    Hardy, Robert Douglas; Bronowski, David R.; Lee, Moo Yul; Hofer, John H.


    An experimental study was conducted to measure the mechanical properties of the Thermal Protection System (TPS) materials used for the Space Shuttle. Three types of TPS materials (LI-900, LI-2200, and FRCI-12) were tested in 'in-plane' and 'out-of-plane' orientations. Four types of quasi-static mechanical tests (uniaxial tension, uniaxial compression, uniaxial strain, and shear) were performed under low (10{sup -4} to 10{sup -3}/s) and intermediate (1 to 10/s) strain rate conditions. In addition, split Hopkinson pressure bar tests were conducted to obtain the strength of the materials under a relatively higher strain rate ({approx}10{sup 2} to 10{sup 3}/s) condition. In general, TPS materials have higher strength and higher Young's modulus when tested in 'in-plane' than in 'through-the-thickness' orientation under compressive (unconfined and confined) and tensile stress conditions. In both stress conditions, the strength of the material increases as the strain rate increases. The rate of increase in LI-900 is relatively small compared to those for the other two TPS materials tested in this study. But, the Young's modulus appears to be insensitive to the different strain rates applied. The FRCI-12 material, designed to replace the heavier LI-2200, showed higher strengths under tensile and shear stress conditions. But, under a compressive stress condition, LI-2200 showed higher strength than FRCI-12. As far as the modulus is concerned, LI-2200 has higher Young's modulus both in compression and in tension. The shear modulus of FRCI-12 and LI-2200 fell in the same range.

  13. Distribution system protection with communication technologies

    DEFF Research Database (Denmark)

    Wei, Mu; Chen, Zhe


    Due to the communication technologies’ involvement in the distribution power system, the time-critical protection function may be implemented more accurately, therefore distribution power systems’ stability, reliability and security could be improved. This paper presents an active distribution...... power system, including CHPs (Combined Heating and Power) and small scaled WTs (Wind Turbines), as a practical example to examine the possible impacts of communication technologies on the power system. Under some fault scenarios, the power system’s responses to the fault are compared between the system...... with communication technologies and that without communication technologies. At the same time, the previously proposed study method of combining the simulations of communication and power systems is adopted in this study. The performance of a communication network adopted for power system is simulated by OPNET...

  14. Comparative Analysis of CTF and Trace Thermal-Hydraulic Codes Using OECD/NRC PSBT Benchmark Void Distribution Database

    Directory of Open Access Journals (Sweden)

    M. Avramova


    Full Text Available The international OECD/NRC PSBT benchmark has been established to provide a test bed for assessing the capabilities of thermal-hydraulic codes and to encourage advancement in the analysis of fluid flow in rod bundles. The benchmark was based on one of the most valuable databases identified for the thermal-hydraulics modeling developed by NUPEC, Japan. The database includes void fraction and departure from nucleate boiling measurements in a representative PWR fuel assembly. On behalf of the benchmark team, PSU in collaboration with US NRC has performed supporting calculations using the PSU in-house advanced thermal-hydraulic subchannel code CTF and the US NRC system code TRACE. CTF is a version of COBRA-TF whose models have been continuously improved and validated by the RDFMG group at PSU. TRACE is a reactor systems code developed by US NRC to analyze transient and steady-state thermal-hydraulic behavior in LWRs and it has been designed to perform best-estimate analyses of LOCA, operational transients, and other accident scenarios in PWRs and BWRs. The paper presents CTF and TRACE models for the PSBT void distribution exercises. Code-to-code and code-to-data comparisons are provided along with a discussion of the void generation and void distribution models available in the two codes.

  15. Distributed operating system for NASA ground stations (United States)

    Doyle, John F.


    NASA ground stations are characterized by ever changing support requirements, so application software is developed and modified on a continuing basis. A distributed operating system was designed to optimize the generation and maintenance of those applications. Unusual features include automatic program generation from detailed design graphs, on-line software modification in the testing phase, and the incorporation of a relational database within a real-time, distributed system.

  16. Performance TTradeoffs in Distributed Control Systems (United States)

    Borowski, Holly

    Large scale systems consisting of many interacting subsystems are often controlled in a distributed fashion due to inherent limitations in computation, communication, or sensing. Here, individual agents must make decisions based on local, often incomplete information. This dissertation focuses on understanding performance tradeoffs in distributed control systems, specifically focusing on using a game theoretic framework to assign agent control laws. Performance of a distributed control law is determined by (1) the degree with which it meets a stated objective, (2) the amount of time it takes to converge, (3) agents' informational requirements, and (4) vulnerability to adversarial manipulation. The three main research questions addressed in this work are: • When is fast convergence to near-optimal behavior possible in a distributed system? We design a distributed control law which converges to a near-optimal configuration in a time that is near-linear in the number of agents. This worst case convergence time is an improvement over existing algorithms whose worst-case convergence times are exponential in the number of agents. • Can agents in a distributed system learn near-optimal correlated behavior despite severely limited information about one another's behavior? We design a distributed control law that imposes limited informational requirements for individual agents and converges to near-optimal correlated behavior. • How does the structure of agent interaction impact a distributed control system's vulnerability to adversarial manipulation? We derive a graph theoretical condition that ensures resilience to adversarial manipulation, and we examine the conditions under which an adversary can manipulate collective behavior in a distributed control system, simply by influencing small subsets of agents.

  17. Thermal control system for SSF sensor/electronics (United States)

    Akau, R. L.; Lee, D. E.


    A thermal control system was designed for the Space Station Freedom (SSF) sensor/electronics box (SSTACK). Multi-layer insulation and heaters are used to maintain the temperatures of the critical components within their operating and survival temperature limits. Detailed and simplified SSTACK thermal models were developed and temperatures were calculated for worst-case orbital conditions. A comparison between the two models showed very good agreement. Temperature predictions were also compared to measured temperatures from a thermal-vacuum test.

  18. Combustion chemical vapor desposited coatings for thermal barrier coating systems

    Energy Technology Data Exchange (ETDEWEB)

    Hampikian, J.M.; Carter, W.B. [Georgia Institute of Technology, Atlanta, GA (United States)


    The new deposition process, combustion chemical vapor deposition, shows a great deal of promise in the area of thermal barrier coating systems. This technique produces dense, adherent coatings, and does not require a reaction chamber. Coatings can therefore be applied in the open atmosphere. The process is potentially suitable for producing high quality CVD coatings for use as interlayers between the bond coat and thermal barrier coating, and/or as overlayers, on top of thermal barrier coatings.

  19. Advanced Fuel Cell System Thermal Management for NASA Exploration Missions (United States)

    Burke, Kenneth A.


    The NASA Glenn Research Center is developing advanced passive thermal management technology to reduce the mass and improve the reliability of space fuel cell systems for the NASA exploration program. An analysis of a state-of-the-art fuel cell cooling systems was done to benchmark the portion of a fuel cell system s mass that is dedicated to thermal management. Additional analysis was done to determine the key performance targets of the advanced passive thermal management technology that would substantially reduce fuel cell system mass.

  20. Photovoltaic solar panel for a hybrid PV/thermal system

    Energy Technology Data Exchange (ETDEWEB)

    Zakharchenko, R.; Licea-Jimenez, L.; Perez-Garcia, S.A.; Perez-Robles, J.F.; Gonzalez-Hernandez, J.; Vorobiev, Y. [CINVESTAV-Queretaro, (Mexico); Vorobiev, P. [Universidad Autonoma de Queretaro, (Mexico). Facultad de Ingenieria; Dehesa-Carrasco, U. [Instituto Tec. Del Istmo, Oaxaco (Mexico). Dep. de Ingenieria Electromecanica


    The hybrid PV-thermal system was studied, with the photovoltaic panel (PVP) area much smaller than that of the solar collector. Performance of the different panels in the system was investigated, in particular, those made of crystalline (c-) Si, {alpha}-Si and CuInSe{sub 2} as well as different materials and constructions for the thermal contact between the panel and the collector. Our conclusion is that the PVP for application in a hybrid system needs a special design providing efficient heat extraction from it. PVP was designed and made. Its study has shown that this design provides the high electrical and thermal efficiency of the hybrid system. (author)


    Directory of Open Access Journals (Sweden)

    Kitaytseva Elena Khalilovna


    Full Text Available Solar thermal system are its constituent elements with their connection between each other, thermal processes within them and also input/output data. The conjunction of external and internal factors determines the efficiency of solar thermal system. No excess heat as well as its deficiency displays us high level efficiency of system. The initial data for modeling of solar thermal systems functioning are dissimilar. Parameters of system’s equipment are constant. Solar radiation amount and water consumption are variable data. The more close initial data to reality, the more definite simulated result is. The main problem is in unpredictability of water consumption by the reason of daily regime and requirement of each user. In this way user is the most instable element of the system. In this study the input data for mathematical modeling of solar thermal systems was analyzed. The climatic databases and standard specifications of hot water demand were also analyzed. The operability estimation method for solar thermal systems with variable input data was offered. The extent of suitability of any solar thermal system can be defined by certain characteristic. The value of this characteristic displays energy accumulation process.

  2. Distributed redundancy and robustness in complex systems

    KAUST Repository

    Randles, Martin


    The uptake and increasing prevalence of Web 2.0 applications, promoting new large-scale and complex systems such as Cloud computing and the emerging Internet of Services/Things, requires tools and techniques to analyse and model methods to ensure the robustness of these new systems. This paper reports on assessing and improving complex system resilience using distributed redundancy, termed degeneracy in biological systems, to endow large-scale complicated computer systems with the same robustness that emerges in complex biological and natural systems. However, in order to promote an evolutionary approach, through emergent self-organisation, it is necessary to specify the systems in an \\'open-ended\\' manner where not all states of the system are prescribed at design-time. In particular an observer system is used to select robust topologies, within system components, based on a measurement of the first non-zero Eigen value in the Laplacian spectrum of the components\\' network graphs; also known as the algebraic connectivity. It is shown, through experimentation on a simulation, that increasing the average algebraic connectivity across the components, in a network, leads to an increase in the variety of individual components termed distributed redundancy; the capacity for structurally distinct components to perform an identical function in a particular context. The results are applied to a specific application where active clustering of like services is used to aid load balancing in a highly distributed network. Using the described procedure is shown to improve performance and distribute redundancy. © 2010 Elsevier Inc.

  3. Simulating the ATLAS Distributed Data Management System

    CERN Document Server

    Barisits, M; Lassnig, M; Molfetas, M


    The ATLAS Distributed Data Management system organizes more than 90PB of physics data across more than 100 sites globally. Over 14 million files are transferred daily with strongly varying usage patterns. For performance and scalability reasons it is imperative to adapt and improve the data management system continuously. Therefore future system modifications in hardware, software, as well as policy, need to be evaluated to accomplish the intended results and to avoid unwanted side effects. Due to the complexity of large- scale distributed systems this evaluation process is primarily based on expert knowledge, as conventional evaluation methods are inadequate. However, this error-prone process lacks quantitative estimations and leads to inaccuracy as well as incorrect conclusions. In this work we present a novel, full-scale simulation framework. This modular simulator is able to accurately model the ATLAS Distributed Data Management system. The design and architecture of the component-based software is presen...

  4. Incoherent Optical Frequency Domain Reflectometry for Distributed Thermal Sensing

    DEFF Research Database (Denmark)

    Karamehmedovic, Emir


    increasing frequency, after which the inverse Fourier transform is applied to the signal from the backscattered light. This technique is compared with the more conventional optical time domain reflectometry, where a short pulse is sent through the fibre, and the location of the scattering section...... developed and implemented in Matlab. The computer model is calibrated and tested, and describes the entire system with high precision. Noise analysis and digital processing of the detected signal are discussed as well. An equation describing the standard deviation of the measured temperature is derived...

  5. Ground fault protectionmethods for distribution systems


    Tavares, Hugo Ricardo dos Santos; Nogueira, Teresa Alexandre


    The system grounding method option has a direct influence on the overall performance of the entire medium voltage network as well as on the ground fault current magnitude. For any kind of grounding systems: ungrounded system, solidly and low impedance grounded and resonant grounded, we can find advantages and disadvantages. A thorough study is necessary to choose the most appropriate grounding protection system. The power distribution utilities justify their choices based on economic and t...

  6. Analysis on energy consumption index system of thermal power plant (United States)

    Qian, J. B.; Zhang, N.; Li, H. F.


    Currently, the increasingly tense situation in the context of resources, energy conservation is a realistic choice to ease the energy constraint contradictions, reduce energy consumption thermal power plants has become an inevitable development direction. And combined with computer network technology to build thermal power “small index” to monitor and optimize the management system, the power plant is the application of information technology and to meet the power requirements of the product market competition. This paper, first described the research status of thermal power saving theory, then attempted to establish the small index system and build “small index” monitoring and optimization management system in thermal power plant. Finally elaborated key issues in the field of small thermal power plant technical and economic indicators to be further studied and resolved.

  7. Thermal modeling of a mini rotor-stator system

    NARCIS (Netherlands)

    Dikmen, E.; van der Hoogt, Peter; de Boer, Andries; Aarts, Ronald G.K.M.; Jonker, Jan B.


    In this study the temperature increase and heat dissipation in the air gap of a cylindrical mini rotor stator system has been analyzed. A simple thermal model based on lumped parameter thermal networks has been developed. With this model the temperature dependent air properties for the fluid-rotor

  8. Thermal and hydraulic analyses of the System 81 cold traps

    Energy Technology Data Exchange (ETDEWEB)

    Kim, K.


    Thermal and hydraulic analyses of the System 81 Type I and II cold traps were completed except for thermal transients analysis. Results are evaluated, discussed, and reported. Analytical models were developed to determine the physical dimensions of the cold traps and to predict the performance. The FFTF cold trap crystallizer performances were simulated using the thermal model. This simulation shows that the analytical model developed predicts reasonably conservative temperatures. Pressure drop and sodium residence time calculations indicate that the present design will meet the requirements specified in the E-Specification. Steady state temperature data for the critical regions were generated to assess the magnitude of the thermal stress.

  9. JPL - Small Power Systems Applications Project. [for solar thermal power plant development and commercialization (United States)

    Ferber, R. R.; Marriott, A. T.; Truscello, V.


    The Small Power Systems Applications (SPSA) Project has been established to develop and commercialize small solar thermal power plants. The technologies of interest include all distributed and central receiver technologies which are potentially economically viable in power plant sizes of one to 10 MWe. The paper presents an overview of the SPSA Project and briefly discusses electric utility involvement in the Project.

  10. Performance of the Amoeba Distributed Operating System

    NARCIS (Netherlands)

    van Renesse, R.; van Staveren, H.; Tanenbaum, A.S.


    Amoeba is a capability‐based distributed operating system designed for high‐performance interactions between clients and servers using the well‐known RPC model. The paper starts out by describing the architecture of the Amoeba system, which is typified by specialized components such as workstations,

  11. Process Management in Distributed Operating Systems

    NARCIS (Netherlands)

    Nehmer, J.; Mullender, Sape J.

    As part of designing and building the Amoeba distributed operating system, we have come up with a simple set of mechanisms for process management that allows downloading process migration, checkpointing, remote debugging and emulation of alien operating system interfaces. The basic process

  12. The evolution of a distributed operating system

    NARCIS (Netherlands)

    R. van Renesse (Robbert); A.S. Tanenbaum (Andrew); S.J. Mullender (Sape)


    textabstractAMOEBA is a research project to build a true distributed operating system using the object model. Under the COST11-ter MANDIS project this work was extended to cover wide-area networks. Besides describing the system, this paper discusses the successive versions in the implementation of

  13. Distributed Database Management Systems A Practical Approach

    CERN Document Server

    Rahimi, Saeed K


    This book addresses issues related to managing data across a distributed database system. It is unique because it covers traditional database theory and current research, explaining the difficulties in providing a unified user interface and global data dictionary. The book gives implementers guidance on hiding discrepancies across systems and creating the illusion of a single repository for users. It also includes three sample frameworksâ€"implemented using J2SE with JMS, J2EE, and Microsoft .Netâ€"that readers can use to learn how to implement a distributed database management system. IT and

  14. Maximizing wind power integration in distribution system

    Energy Technology Data Exchange (ETDEWEB)

    Nursebo Salih, S.; Chen, Peiyuan; Carlson, Ola [Chalmers Univ. of Technology (Sweden)


    Due to the location of favorable wind sites and lower connection costs associated with installing wind power in a distribution system, there is a need to know the hosting capacity of a distribution system so that it can be used effectively for injecting wind power into the power system. Therefore this paper presents a methodology to investigate the wind power hosting capacity of a distribution system. Stochastic nature of wind power and customer loads is taken into account using copulas. Hence it is possible to investigate various levels of correlation among customer loads. A simple algorithm is proposed for selecting the connection points of wind power in the network. The effectiveness of active management strategies such as wind power curtailment and reactive power compensation are thoroughly investigated. The analysis shows that allowing a curtailment level of as low as 0.2% with power factor (PF) control of wind turbines could boost the hosting capacity by 118%. (orig.)

  15. The art of software thermal management for embedded systems

    CERN Document Server

    Benson, Mark


    This book introduces Software Thermal Management (STM) as a means of reducing power consumption in a computing system, in order to manage heat, improve component reliability, and increase system safety.  Readers will benefit from this pragmatic guide to the field of STM for embedded systems and its catalog of software power management techniques.  Since thermal management is a key bottleneck in embedded systems design, this book focuses on power as the root cause of heat. Since software has an enormous impact on power consumption in an embedded system, this book guides readers to manage heat effectively by understanding, categorizing, and developing new ways to reduce dynamic power. Whereas most books on thermal management describe mechanisms to remove heat, this book focuses on ways to avoid generating heat in the first place.   • Explains fundamentals of software thermal management, application techniques and advanced optimization strategies; • Describes a novel method for managing dynamic power, e...

  16. Resonance width distribution for open quantum systems (United States)

    Shchedrin, Gavriil; Zelevinsky, Vladimir


    Recent measurements of resonance widths for low-energy neutron scattering off heavy nuclei show large deviations from the Porter-Thomas distribution. We propose a “standard” width distribution based on the random matrix theory for a chaotic quantum system with a single open decay channel. Two methods of derivation lead to a single analytical expression that recovers, in the limit of very weak continuum coupling, the Porter-Thomas distribution. The parameter defining the result is the ratio of typical widths Γ to the energy level spacing D. Compared to the Porter-Thomas distribution, the new distribution suppresses small widths and increases the probabilities of larger widths. We show also that it is necessary to take into account the γ channels.

  17. Fractal analysis of the effect of particle aggregation distribution on thermal conductivity of nanofluids

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Wei, E-mail: [Hubei Subsurface Multi-scale Imaging Key Laboratory, Institute of Geophysics and Geomatics, China University of Geosciences, Wuhan 430074 (China); Cai, Jianchao, E-mail: [Hubei Subsurface Multi-scale Imaging Key Laboratory, Institute of Geophysics and Geomatics, China University of Geosciences, Wuhan 430074 (China); Hu, Xiangyun, E-mail: [Hubei Subsurface Multi-scale Imaging Key Laboratory, Institute of Geophysics and Geomatics, China University of Geosciences, Wuhan 430074 (China); Han, Qi, E-mail: [Hubei Subsurface Multi-scale Imaging Key Laboratory, Institute of Geophysics and Geomatics, China University of Geosciences, Wuhan 430074 (China); Liu, Shuang, E-mail: [Hubei Subsurface Multi-scale Imaging Key Laboratory, Institute of Geophysics and Geomatics, China University of Geosciences, Wuhan 430074 (China); Zhou, Yingfang, E-mail: [School of Engineering, University of Aberdeen, FN 264, King' s College, Aberdeen, AB24 3UE (United Kingdom)


    A theoretical effective thermal conductivity model for nanofluids is derived based on fractal distribution characteristics of nanoparticle aggregation. Considering two different mechanisms of heat conduction including particle aggregation and convention, the model is expressed as a function of the fractal dimension and concentration. In the model, the change of fractal dimension is related to the variation of aggregation shape. The theoretical computations of the developed model provide a good agreement with the experimental results, which may serve as an effective approach for quantitatively estimating the effective thermal conductivity of nanofluids. - Highlights: • A thermal conductivity model is derived based on fractal aggregation distribution. • The relationship between aggregation shape and fractal dimension is analyzed. • Predictions of the proposed model show good agreement with experimental data.

  18. Distributed Monitoring System Based on ICINGA

    CERN Multimedia

    Haen, C; Neufeld, N


    The LHCb online system relies on a large and heterogeneous I.T. infrastructure : it comprises more than 2000 servers and embedded systems and more than 200 network devices. While for the control and monitoring of detectors, PLCs, and readout boards an industry standard SCADA system PVSSII has been put in production, we use a low level monitoring system to monitor the control infrastructure itself. While our previous system was based on a single central NAGIOS server, our current system uses a distributed ICINGA infrastructure.

  19. Analysis of thermal distribution in two end pumping Nd: YAG laser ...

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 80; Issue 3. Analysis of ... Abstract. There is a strong need for the optimized management of the thermal problem in Nd:YAG laser rod and for a powerful, fast, and accurate modelling tool capable of treating the heat source distribution very close to what it actually is.

  20. Synchronization in Quantum Key Distribution Systems

    Directory of Open Access Journals (Sweden)

    Anton Pljonkin


    Full Text Available In the description of quantum key distribution systems, much attention is paid to the operation of quantum cryptography protocols. The main problem is the insufficient study of the synchronization process of quantum key distribution systems. This paper contains a general description of quantum cryptography principles. A two-line fiber-optic quantum key distribution system with phase coding of photon states in transceiver and coding station synchronization mode was examined. A quantum key distribution system was built on the basis of the scheme with automatic compensation of polarization mode distortions. Single-photon avalanche diodes were used as optical radiation detecting devices. It was estimated how the parameters used in quantum key distribution systems of optical detectors affect the detection of the time frame with attenuated optical pulse in synchronization mode with respect to its probabilistic and time-domain characteristics. A design method was given for the process that detects the time frame that includes an optical pulse during synchronization. This paper describes the main quantum communication channel attack methods by removing a portion of optical emission. This paper describes the developed synchronization algorithm that takes into account the time required to restore the photodetector’s operation state after the photon has been registered during synchronization. The computer simulation results of the developed synchronization algorithm were analyzed. The efficiency of the developed algorithm with respect to synchronization process protection from unauthorized gathering of optical emission is demonstrated herein.

  1. Distance Protection for Microgrids in Distribution System


    Lin, Hengwei; Liu, Chengxi; Josep M. Guerrero; Quintero, Juan Carlos Vasquez


    Owing to the increasing penetration of distributed generation, there are some challenges for the conventional protection in distribution system. Bidirectional power flow and variable fault current because of the various operation modes may lead to the selectivity and sensitivity of the overcurrent protection decreased. This paper adopts distance protection for one mid-voltage level microgrid in Aalborg, Denmark. Different operation modes of the network are analyzed and tested in the paper. Th...

  2. Smart grids concept in electrical distribution system

    Directory of Open Access Journals (Sweden)

    Popović Željko N.


    Full Text Available This paper defines key business processes in electrical distribution systems and key elements and priority components that should be (redefined in these processes in order to enable the goals of smart grids concept to be fulfilled in the cost effective way. Activities undertaken in the Power Distribution Company of “Elektrovojvodina” (Serbia, which provide the basis for fulfilling the Smart Grids goals and thus enable full implementation of smart grids concept are presented in details.

  3. A distributed clinical decision support system architecture


    Shaker H. El-Sappagh; El-Masri, Samir


    This paper proposes an open and distributed clinical decision support system architecture. This technical architecture takes advantage of Electronic Health Record (EHR), data mining techniques, clinical databases, domain expert knowledge bases, available technologies and standards to provide decision-making support for healthcare professionals. The architecture will work extremely well in distributed EHR environments in which each hospital has its own local EHR, and it satisfies the compatibi...

  4. A Global Enviromental Data Distribution System


    Walker, Philip


    This paper describes a global environmental data distribution system (GEDDS) which uses a single small satellite operating in a low polar orbit. The satellite collects environmental data from remotely located instrumentation platforms and distributes it to research laboratories and other interested organizations virtually anywhere in the world. A command link also allows principal investigators to control and calibrate platform instruments on a daily basis directly from their laboratory or of...

  5. Energy optimization of water distribution system

    Energy Technology Data Exchange (ETDEWEB)


    In order to analyze pump operating scenarios for the system with the computer model, information on existing pumping equipment and the distribution system was collected. The information includes the following: component description and design criteria for line booster stations, booster stations with reservoirs, and high lift pumps at the water treatment plants; daily operations data for 1988; annual reports from fiscal year 1987/1988 to fiscal year 1991/1992; and a 1985 calibrated KYPIPE computer model of DWSD`s water distribution system which included input data for the maximum hour and average day demands on the system for that year. This information has been used to produce the inventory database of the system and will be used to develop the computer program to analyze the system.

  6. Thermal Analysis for Ion-Exchange Column System

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Si Y.; King, William D.


    Models have been developed to simulate the thermal characteristics of crystalline silicotitanate ion exchange media fully loaded with radioactive cesium either in a column configuration or distributed within a waste storage tank. This work was conducted to support the design and operation of a waste treatment process focused on treating dissolved, high-sodium salt waste solutions for the removal of specific radionuclides. The ion exchange column will be installed inside a high level waste storage tank at the Savannah River Site. After cesium loading, the ion exchange media may be transferred to the waste tank floor for interim storage. Models were used to predict temperature profiles in these areas of the system where the cesium-loaded media is expected to lead to localized regions of elevated temperature due to radiolytic decay. Normal operating conditions and accident scenarios (including loss of solution flow, inadvertent drainage, and loss of active cooling) were evaluated for the ion exchange column using bounding conditions to establish the design safety basis. The modeling results demonstrate that the baseline design using one central and four outer cooling tubes provides a highly efficient cooling mechanism for reducing the maximum column temperature. In-tank modeling results revealed that an idealized hemispherical mound shape leads to the highest tank floor temperatures. In contrast, even large volumes of CST distributed in a flat layer with a cylindrical shape do not result in significant floor heating.

  7. Thermal Analysis of Ball screw Systems by Explicit Finite Difference Method

    Energy Technology Data Exchange (ETDEWEB)

    Min, Bog Ki [Hanyang Univ., Seoul (Korea, Republic of); Park, Chun Hong; Chung, Sung Chong [KIMM, Daejeon (Korea, Republic of)


    Friction generated from balls and grooves incurs temperature rise in the ball screw system. Thermal deformation due to the heat degrades positioning accuracy of the feed drive system. To compensate for the thermal error, accurate prediction of the temperature distribution is required first. In this paper, to predict the temperature distribution according to the rotational speed, solid and hollow cylinders are applied for analysis of the ball screw shaft and nut, respectively. Boundary conditions such as the convective heat transfer coefficient, friction torque, and thermal contact conductance (TCC) between balls and grooves are formulated according to operating and fabrication conditions of the ball screw. Explicit FDM (finite difference method) is studied for development of a temperature prediction simulator. Its effectiveness is verified through numerical analysis.

  8. Residential Solar-Based Seasonal Thermal Storage Systems in Cold Climates: Building Envelope and Thermal Storage


    Alexandre Hugo; Radu Zmeureanu


    The reduction of electricity use for heating and domestic hot water in cold climates can be achieved by: (1) reducing the heating loads through the improvement of the thermal performance of house envelopes, and (2) using solar energy through a residential solar-based thermal storage system. First, this paper presents the life cycle energy and cost analysis of a typical one-storey detached house, located in Montreal, Canada. Simulation of annual energy use is performed using the TRNSYS softwar...

  9. Clinical Outcomes Associated with Thermal Pulsation System Treatment

    National Research Council Canada - National Science Library

    Satjawatcharaphong, Pam; Ge, Shaokui; Lin, Meng C


    PURPOSETo identify patient characteristics at a baseline ocular surface evaluation that correlate with improvement in dry eye symptoms at a follow-up visit after treatment with the LipiFlow Thermal Pulsation System...

  10. Development of Advanced Thermal ana Electric Propulsion (TEP) System

    National Research Council Canada - National Science Library

    Tabibi, Bagher


    On September 30, 1993, the Department of Physics at Hampton University was awarded a research instrumentation grant by the AFOSR for the development of an advanced Thermal and Electric Propulsion (TEP) system...


    National Aeronautics and Space Administration — The main goal of spacecraft thermal control systems is to maintain internal and external temperature within acceptable boundaries while minimizing impact on vehicle...

  12. Thermal Protection System Materials (TPSM): 3D MAT Project (United States)

    National Aeronautics and Space Administration — The 3D MAT Project seeks to design and develop a game changing Woven Thermal Protection System (TPS) technology tailored to meet the needs of the Orion Multi-Purpose...

  13. Spacecraft Thermal Control System Not Requiring Power Project (United States)

    National Aeronautics and Space Administration — The thermal management of spacecraft would be enhanced by dynamic control over surface emissivity in the mid-infrared. In this SBIR program, Triton Systems proposes...

  14. In Situ Diagnostic Sensors for Thermal Protection Systems Project (United States)

    National Aeronautics and Space Administration — Low-profile, embedded sensors are proposed for condition monitoring and health management (HM) of thermal protection systems. The sensors will be fabricated using a...

  15. A Distributed Intelligent System for Emergency Convoy

    Directory of Open Access Journals (Sweden)

    Mohammed Benalla


    Full Text Available The general problem that guides this research is the ability to design a distributed intelligent system for guiding the emergency convoys; a solution that will be based on a group of agents and on the analysis of traffic in order to generate collective functional response. It fits into the broader issue of Distributed Artificial System (DAI, which is to operate a cooperatively computer agent into multi-agents system (MAS. This article describes conceptually two fundamental questions of emergency convoys. The first question is dedicated to find a response to the traffic situation (i.e. fluid way, while the second is devoted to the convoy orientation; while putting the point on the distributed and cooperative resolution for the general problem.

  16. Standard Data Exchanges for Distribution System Management

    Energy Technology Data Exchange (ETDEWEB)

    Thomas E. McDermott


    Databases and software tools for electric power distribution systems have not been integrated, and this leads to extra costs and restrictions imposed on utilities and other stakeholders. For example, distributed resource integration studies and modern grid technology assessments are more difficult and costly. New vendors face high market entry barriers, because it’s necessary to interface with large and customized data systems at each potential utility customer. This project promotes data and software tool integration, through a set of data translators based on a common object model. The data translators are delivered as open-source software, using appropriate Web software technologies. The parties who benefit include electric utilities (and their ratepayers), researchers at government laboratories and universities, small software companies wishing to enter the electric utility market, and parties wishing to interconnect distributed generation to a utility system.

  17. The ATLAS Distributed Data Management System & Databases

    CERN Document Server

    Garonne, V; The ATLAS collaboration; Barisits, M; Beermann, T; Vigne, R; Serfon, C


    The ATLAS Distributed Data Management (DDM) System is responsible for the global management of petabytes of high energy physics data. The current system, DQ2, has a critical dependency on Relational Database Management Systems (RDBMS), like Oracle. RDBMS are well-suited to enforcing data integrity in online transaction processing applications, however, concerns have been raised about the scalability of its data warehouse-like workload. In particular, analysis of archived data or aggregation of transactional data for summary purposes is problematic. Therefore, we have evaluated new approaches to handle vast amounts of data. We have investigated a class of database technologies commonly referred to as NoSQL databases. This includes distributed filesystems, like HDFS, that support parallel execution of computational tasks on distributed data, as well as schema-less approaches via key-value stores, like HBase. In this talk we will describe our use cases in ATLAS, share our experiences with various databases used ...

  18. Cardea: Dynamic Access Control in Distributed Systems (United States)

    Lepro, Rebekah


    Modern authorization systems span domains of administration, rely on many different authentication sources, and manage complex attributes as part of the authorization process. This . paper presents Cardea, a distributed system that facilitates dynamic access control, as a valuable piece of an inter-operable authorization framework. First, the authorization model employed in Cardea and its functionality goals are examined. Next, critical features of the system architecture and its handling of the authorization process are then examined. Then the S A M L and XACML standards, as incorporated into the system, are analyzed. Finally, the future directions of this project are outlined and connection points with general components of an authorization system are highlighted.

  19. Thermal processing system concepts and considerations for RWMC buried waste

    Energy Technology Data Exchange (ETDEWEB)

    Eddy, T.L.; Kong, P.C.; Raivo, B.D.; Anderson, G.L.


    This report presents a preliminary determination of ex situ thermal processing system concepts and related processing considerations for application to remediation of transuranic (TRU)-contaminated buried wastes (TRUW) at the Radioactive Waste Management Complex (RWMC) of the Idaho National Engineering Laboratory (INEL). Beginning with top-level thermal treatment concepts and requirements identified in a previous Preliminary Systems Design Study (SDS), a more detailed consideration of the waste materials thermal processing problem is provided. Anticipated waste stream elements and problem characteristics are identified and considered. Final waste form performance criteria, requirements, and options are examined within the context of providing a high-integrity, low-leachability glass/ceramic, final waste form material. Thermal processing conditions required and capability of key systems components (equipment) to provide these material process conditions are considered. Information from closely related companion study reports on melter technology development needs assessment and INEL Iron-Enriched Basalt (IEB) research are considered. Five potentially practicable thermal process system design configuration concepts are defined and compared. A scenario for thermal processing of a mixed waste and soils stream with essentially no complex presorting and using a series process of incineration and high temperature melting is recommended. Recommendations for applied research and development necessary to further detail and demonstrate the final waste form, required thermal processes, and melter process equipment are provided.

  20. Battery management systems with thermally integrated fire suppression (United States)

    Bandhauer, Todd M.; Farmer, Joseph C.


    A thermal management system is integral to a battery pack and/or individual cells. It relies on passive liquid-vapor phase change heat removal to provide enhanced thermal protection via rapid expulsion of inert high pressure refrigerant during abnormal abuse events and can be integrated with a cooling system that operates during normal operation. When a thermal runaway event occurs and sensed by either active or passive sensors, the high pressure refrigerant is preferentially ejected through strategically placed passages within the pack to rapidly quench the battery.

  1. Clinical outcomes associated with thermal pulsation system treatment


    Satjawatcharaphong, P; S. Ge; Lin, MC


    © 2015 American Academy of Optometry. Purpose To identify patient characteristics at a baseline ocular surface evaluation that correlate with improvement in dry eye symptoms at a follow-up visit after treatment with the LipiFlow Thermal Pulsation System. Methods Thirty-two patients completed a comprehensive baseline ocular surface evaluation and were treated with the LipiFlow Thermal Pulsation System followed by maintenance home therapy. Lipid layer thickness and blink pattern were determined...

  2. A review on hybrid photovoltaic/thermal collectors and systems


    Riffat, Saffa B.; Erdem Cuce


    In this paper, a thorough review of the available literature on photovoltaic/thermal (PV/T) systems is presented. The review is performed in a thematic way in order to allow an easier comparison, discussion and evaluation of the findings obtained by researchers, especially on parameters affecting the electrical and thermal performance of PV/T systems. The review covers a comprehensive historic overview of PV/T technology, detailed description of conventional flat-plate and concentrating PV/T ...

  3. Converters for Distributed Power Generation Systems

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Yang, Yongheng


    Power electronics technology has become the enabling technology for the integration of distributed power generation systems (DPGS) such as offshore wind turbine power systems and commercial photovoltaic power plants. Depending on the applications, a vast array of DPGS-based power converter...... presents an overview of the power converters for the DPGS, mainly based on wind turbine systems and photovoltaic systems, covering a wide range of applications. Moreover, the modulation schemes and interfacing power filters for the power converters are also exemplified. Finally, the general control...... topologies has been developed and more are coming into the market in order to achieve an efficient and reliable power conversion from the renewables. In addition, stringent demands from both the distribution system operators and the consumers have been imposed on the renewable-based DPGS. This article...

  4. Concurrency control in distributed database systems

    CERN Document Server

    Cellary, W; Gelenbe, E


    Distributed Database Systems (DDBS) may be defined as integrated database systems composed of autonomous local databases, geographically distributed and interconnected by a computer network.The purpose of this monograph is to present DDBS concurrency control algorithms and their related performance issues. The most recent results have been taken into consideration. A detailed analysis and selection of these results has been made so as to include those which will promote applications and progress in the field. The application of the methods and algorithms presented is not limited to DDBSs but a

  5. Thermal Management System for Superconducting Aircraft Project (United States)

    National Aeronautics and Space Administration — Aircraft powered by hydrogen power plants or gas turbines driving electric generators connected to distributed electric motors for propulsion have the potential to...

  6. DC Home Appliances for DC Distribution System

    Directory of Open Access Journals (Sweden)



    Full Text Available This paper strengthens the idea of DC distribution system for DC microgrid consisting of a building of 50 apartments. Since the war of currents AC system has been dominant because of the paucity of research in the protection of the DC system. Now with the advance research in power electronics material and components, generation of electricity is inherently DC as by solar PV, fuel cell and thermoelectric generator that eliminates the rectification process. Transformers are replaced by the power electronics buck-boost converters. DC circuit breakers have solved the protection problems for both DC transmission and distribution system. In this paper 308V DC microgrid is proposed and home appliances (DC internal are modified to operate on 48V DC from DC distribution line. Instead of using universal and induction motors in rotary appliances, BLDC (Brushless DC motors are proposed that are highly efficient with minimum electro-mechanical and no commutation losses. Proposed DC system reduces the power conversion stages, hence diminishes the associated power losses and standby losses that boost the overall system efficiency. So in view of all this a conventional AC system can be replaced by a DC system that has many advantages by cost as well as by performance

  7. Thermalization and its mechanism for generic isolated quantum systems. (United States)

    Rigol, Marcos; Dunjko, Vanja; Olshanii, Maxim


    An understanding of the temporal evolution of isolated many-body quantum systems has long been elusive. Recently, meaningful experimental studies of the problem have become possible, stimulating theoretical interest. In generic isolated systems, non-equilibrium dynamics is expected to result in thermalization: a relaxation to states in which the values of macroscopic quantities are stationary, universal with respect to widely differing initial conditions, and predictable using statistical mechanics. However, it is not obvious what feature of many-body quantum mechanics makes quantum thermalization possible in a sense analogous to that in which dynamical chaos makes classical thermalization possible. For example, dynamical chaos itself cannot occur in an isolated quantum system, in which the time evolution is linear and the spectrum is discrete. Some recent studies even suggest that statistical mechanics may give incorrect predictions for the outcomes of relaxation in such systems. Here we demonstrate that a generic isolated quantum many-body system does relax to a state well described by the standard statistical-mechanical prescription. Moreover, we show that time evolution itself plays a merely auxiliary role in relaxation, and that thermalization instead happens at the level of individual eigenstates, as first proposed by Deutsch and Srednicki. A striking consequence of this eigenstate-thermalization scenario, confirmed for our system, is that knowledge of a single many-body eigenstate is sufficient to compute thermal averages-any eigenstate in the microcanonical energy window will do, because they all give the same result.

  8. Thermal Vacuum/Balance Test Results of Swift BAT with Loop Heat Pipe Thermal System (United States)

    Choi, Michael K.


    The Swift Burst Alert Telescope (BAT) Detector Array is thermally well coupled to eight constant conductance heat pipes (CCHPs) embedded in the Detector Array Plate PAP), and two loop heat pipes (LHPs) transport heat from the CCHPs to a radiator. The CCHPs have ammonia as the working fluid and the LHPs have propylene as the working fluid. Precision heater controllers, which have adjustable set points in flight, are used to control the LHP compensation chamber and Detector Array xA1 ASIC temperatures. The radiator has AZ-Tek's AZW-LA-II low solar absorptance white paint as the thermal coating, and is located on the anti-sun side of the spacecraft. A thermal balance (T/B) test on the BAT was successfully completed. It validated that the thermal design satisfies the temperature requirements of the BAT in the flight thermal environments. Instrument level and observatory level thermal vacuum (TN) cycling tests of the BAT Detector Array by using the LHP thermal system were successfully completed. This paper presents the results of the T/B test and T N cycling tests.

  9. Solar thermal repowering systems integration. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Dubberly, L. J.; Gormely, J. E.; McKenzie, A. W.


    This report is a solar repowering integration analysis which defines the balance-of-plant characteristics and costs associated with the solar thermal repowering of existing gas/oil-fired electric generating plants. Solar repowering interface requirements for water/steam and salt or sodium-cooled central receivers are defined for unit sizes ranging from 50 MWe non-reheat to 350 MWe reheat. Finally balance-of-plant cost estimates are presented for each of six combinations of plant type, receiver type and percent solar repowering.

  10. Correlation between seismicity and the distribution of thermal and carbonate water in southern and Baja California, United States and Mexico (United States)

    Gastil, Gordon; Bertine, Kathe


    A comparison of the distribution of thermal and thermal-related springs and wells in southern California, United States, and Baja California, Mexico, with the abundance of earthquakes of magnitude 4 or greater shows as close a relationship between thermal waters and the distribution of seismicity as to the distribution of active faults. It appears that the distribution of thermal water variations in the geothermal gradient in turn influences the stress accumulation capability of the rocks at depth. Thus, areas with abundant thermal waters (and hence steep geothermal gradients) release stress by frequent moderate earthquakes; areas lacking thermal waters, such as the central Transverse Ranges, accumulate stresses that are released by infrequent large earthquakes.

  11. Thermalization and Return to Equilibrium on Finite Quantum Lattice Systems (United States)

    Farrelly, Terry; Brandão, Fernando G. S. L.; Cramer, Marcus


    Thermal states are the bedrock of statistical physics. Nevertheless, when and how they actually arise in closed quantum systems is not fully understood. We consider this question for systems with local Hamiltonians on finite quantum lattices. In a first step, we show that states with exponentially decaying correlations equilibrate after a quantum quench. Then, we show that the equilibrium state is locally equivalent to a thermal state, provided that the free energy of the equilibrium state is sufficiently small and the thermal state has exponentially decaying correlations. As an application, we look at a related important question: When are thermal states stable against noise? In other words, if we locally disturb a closed quantum system in a thermal state, will it return to thermal equilibrium? We rigorously show that this occurs when the correlations in the thermal state are exponentially decaying. All our results come with finite-size bounds, which are crucial for the growing field of quantum thermodynamics and other physical applications.

  12. Wireless distributed functional electrical stimulation system

    Directory of Open Access Journals (Sweden)

    Jovičić Nenad S


    Full Text Available Abstract Background The control of movement in humans is hierarchical and distributed and uses feedback. An assistive system could be best integrated into the therapy of a human with a central nervous system lesion if the system is controlled in a similar manner. Here, we present a novel wireless architecture and routing protocol for a distributed functional electrical stimulation system that enables control of movement. Methods The new system comprises a set of miniature battery-powered devices with stimulating and sensing functionality mounted on the body of the subject. The devices communicate wirelessly with one coordinator device, which is connected to a host computer. The control algorithm runs on the computer in open- or closed-loop form. A prototype of the system was designed using commercial, off-the-shelf components. The propagation characteristics of electromagnetic waves and the distributed nature of the system were considered during the development of a two-hop routing protocol, which was implemented in the prototype’s software. Results The outcomes of this research include a novel system architecture and routing protocol and a functional prototype based on commercial, off-the-shelf components. A proof-of-concept study was performed on a hemiplegic subject with paresis of the right arm. The subject was tasked with generating a fully functional palmar grasp (closing of the fingers. One node was used to provide this movement, while a second node controlled the activation of extensor muscles to eliminate undesired wrist flexion. The system was tested with the open- and closed-loop control algorithms. Conclusions The system fulfilled technical and application requirements. The novel communication protocol enabled reliable real-time use of the system in both closed- and open-loop forms. The testing on a patient showed that the multi-node system could operate effectively to generate functional movement.

  13. Wireless distributed functional electrical stimulation system. (United States)

    Jovičić, Nenad S; Saranovac, Lazar V; Popović, Dejan B


    The control of movement in humans is hierarchical and distributed and uses feedback. An assistive system could be best integrated into the therapy of a human with a central nervous system lesion if the system is controlled in a similar manner. Here, we present a novel wireless architecture and routing protocol for a distributed functional electrical stimulation system that enables control of movement. The new system comprises a set of miniature battery-powered devices with stimulating and sensing functionality mounted on the body of the subject. The devices communicate wirelessly with one coordinator device, which is connected to a host computer. The control algorithm runs on the computer in open- or closed-loop form. A prototype of the system was designed using commercial, off-the-shelf components. The propagation characteristics of electromagnetic waves and the distributed nature of the system were considered during the development of a two-hop routing protocol, which was implemented in the prototype's software. The outcomes of this research include a novel system architecture and routing protocol and a functional prototype based on commercial, off-the-shelf components. A proof-of-concept study was performed on a hemiplegic subject with paresis of the right arm. The subject was tasked with generating a fully functional palmar grasp (closing of the fingers). One node was used to provide this movement, while a second node controlled the activation of extensor muscles to eliminate undesired wrist flexion. The system was tested with the open- and closed-loop control algorithms. The system fulfilled technical and application requirements. The novel communication protocol enabled reliable real-time use of the system in both closed- and open-loop forms. The testing on a patient showed that the multi-node system could operate effectively to generate functional movement.

  14. Power capability in low voltage dc distribution systems

    National Research Council Canada - National Science Library

    CO Gecan; Chindris; R Bindiu


    ... a LVDC distribution system. The paper presents some general considerations regarding cables used in a LVAC distribution system and different line reconfigurations witch enable the use of cobles in a LVDC distribution system...

  15. Residential Solar-Based Seasonal Thermal Storage Systems in Cold Climates: Building Envelope and Thermal Storage

    Directory of Open Access Journals (Sweden)

    Alexandre Hugo


    Full Text Available The reduction of electricity use for heating and domestic hot water in cold climates can be achieved by: (1 reducing the heating loads through the improvement of the thermal performance of house envelopes, and (2 using solar energy through a residential solar-based thermal storage system. First, this paper presents the life cycle energy and cost analysis of a typical one-storey detached house, located in Montreal, Canada. Simulation of annual energy use is performed using the TRNSYS software. Second, several design alternatives with improved thermal resistance for walls, ceiling and windows, increased overall air tightness, and increased window-to-wall ratio of South facing windows are evaluated with respect to the life cycle energy use, life cycle emissions and life cycle cost. The solution that minimizes the energy demand is chosen as a reference house for the study of long-term thermal storage. Third, the computer simulation of a solar heating system with solar thermal collectors and long-term thermal storage capacity is presented. Finally, the life cycle cost and life cycle energy use of the solar combisystem are estimated for flat-plate solar collectors and evacuated tube solar collectors, respectively, for the economic and climatic conditions of this study.

  16. Thermal-Mechanical Optimization of Folded Core Sandwich Panels for Thermal Protection Systems of Space Vehicles

    Directory of Open Access Journals (Sweden)

    Chen Zhou


    Full Text Available The integrated thermal protection system (ITPS is a complicated system that addresses both mechanical and thermal considerations. An M-pattern folded core sandwich panel packed with low-density insulation material provides inherently low mass for a potential ITPS panel. Herein, we identify the most influential geometric parameters and establish a viable, computationally efficient optimization procedure. Variables considered for optimization are geometric dimensions of the ITPS, while temperature and deflection are taken as constraints. A one-dimensional (1D thermal model based on a modified form of the rule of mixtures was established, while a three-dimensional (3D model was adopted for linear static analyses. Parametric models were generated to facilitate a design of experiment (DOE study, and approximate models using radial basis functions were obtained to carry out the optimization process. Sensitivity studies were first conducted to investigate the effect of geometric parameters on the ITPS responses. Then optimizations were performed for both thermal and thermal-mechanical constraints. The results show that the simplified 1D thermal model is able to predict temperature through the ITPS thickness satisfactorily. The combined optimization strategy evidently improves the computational efficiency of the design process showing it can be used for initial design of folded core ITPS.

  17. Deceit: A flexible distributed file system (United States)

    Siegel, Alex; Birman, Kenneth; Marzullo, Keith


    Deceit, a distributed file system (DFS) being developed at Cornell, focuses on flexible file semantics in relation to efficiency, scalability, and reliability. Deceit servers are interchangeable and collectively provide the illusion of a single, large server machine to any clients of the Deceit service. Non-volatile replicas of each file are stored on a subset of the file servers. The user is able to set parameters on a file to achieve different levels of availability, performance, and one-copy serializability. Deceit also supports a file version control mechanism. In contrast with many recent DFS efforts, Deceit can behave like a plain Sun Network File System (NFS) server and can be used by any NFS client without modifying any client software. The current Deceit prototype uses the ISIS Distributed Programming Environment for all communication and process group management, an approach that reduces system complexity and increases system robustness.

  18. Distributed Monitoring System Based on ICINGA

    CERN Document Server

    Haen, C; Neufeld, N


    The LHCb online system relies on a large and heterogeneous IT infrastructure: it comprises more than 2000 servers and embedded systems and more than 200 network devices. Many of these equipments are critical in order to run the experiment, and it is important to have a monitoring solution performant enough so that the experts can diagnose and act quickly. While our previous system was based on a central Nagios server, our current system uses a distributed Icinga infrastructure. The LHCb installation schema will be presented here, as well some performance comparisons and custom tools.

  19. Improved Thermal-Insulation Systems for Low Temperatures (United States)

    Fesmire, James E.; Augustynowicz, Stanislaw D.


    Improved thermal-insulation materials and structures and the techniques for manufacturing them are undergoing development for use in low-temperature applications. Examples of low-temperature equipment for which these thermal insulation systems could provide improved energy efficiency include storage tanks for cryogens, superconducting electric-power-transmission equipment, containers for transport of food and other perishable commodities, and cold boxes for low-temperature industrial processes. These systems could also be used to insulate piping used to transfer cryogens and other fluids, such as liquefied natural gas, refrigerants, chilled water, crude oil, or low-pressure steam. The present thermal-insulation systems are layer composites based partly on the older class of thermal-insulation systems denoted generally as multilayer insulation (MLI). A typical MLI structure includes an evacuated jacket, within which many layers of radiation shields are stacked or wrapped close together. Low-thermal-conductivity spacers are typically placed between the reflection layers to keep them from touching. MLI can work very well when a high vacuum level (less than 10(exp-4) torr) is maintained and utmost care is taken during installation, but its thermal performance deteriorates sharply as the pressure in the evacuated space rises into the soft vacuum range [pressures greater than 0.1 torr (greater than 13 Pa)]. In addition, the thermal performance of MLI is extremely sensitive to mechanical compression and edge effects and can easily decrease from one to two orders of magnitude from its ideal value even when the MLI is kept under high vacuum condition. The present thermal-insulation systems are designed to perform well under soft vacuum level, in particular the range of 1 to 10 torr. They are also designed with larger interlayer spacings to reduce vulnerability to compression (and consequent heat leak) caused by installation and use. The superiority of these systems is the

  20. Planning and Optimization Methods for Active Distribution Systems

    DEFF Research Database (Denmark)

    Abbey, Chad; Baitch, Alex; Bak-Jensen, Birgitte

    distribution planning. Active distribution networks (ADNs) have systems in place to control a combination of distributed energy resources (DERs), defined as generators, loads and storage. With these systems in place, the AND becomes an Active Distribution System (ADS). Distribution system operators (DSOs) have...

  1. Integrated thermal treatment system sudy: Phase 2, Results

    Energy Technology Data Exchange (ETDEWEB)

    Feizollahi, F.; Quapp, W.J.


    This report presents the second phase of a study on thermal treatment technologies. The study consists of a systematic assessment of nineteen thermal treatment alternatives for the contact-handled mixed low-level waste (MLLW) currently stored in the US Department of Energy complex. The treatment alternatives consist of widely varying technologies for safely destroying the hazardous organic components, reducing the volume, and preparing for final disposal of the MLLW. The alternatives considered in Phase 2 were innovative thermal treatments with nine types of primary processing units. Other variations in the study examined the effect of combustion gas, air pollution control system design, and stabilization technology for the treatment residues. The Phase 1 study, the results of which have been published as an interim report, examined ten initial thermal treatment alternatives. The Phase 2 systems were evaluated in essentially the same manner as the Phase 2 systems. The assumptions and methods were the same as for the Phase 1 study. The quantities, and physical and chemical compositions, of the input waste used in he Phase 2 systems differ from those in the Phase 1 systems, which were based on a preliminary waste input database developed at the onset of the Integrated Thermal Treatment System study. The inventory database used in the Phase 2 study incorporates the latest US Department of Energy information. All systems, both primary treatment systems and subsystem inputs, have now been evaluated using the same waste input (2,927 lb/hr).

  2. The "Family Tree" of Air Distribution Systems

    DEFF Research Database (Denmark)

    Nielsen, Peter V.


    that all the known types of air distribution systems are interconnected in a “family tree”. The influence of supplied momentum flow versus buoyancy forces is discussed, and geometries for high ventilation effectiveness are indicated as well as geometries for fully mixed flow. The paper will also show...

  3. Distribution system reliability evaluation using credibility theory

    African Journals Online (AJOL)

    Xufeng Xu, Joydeep Mitra

    trapezoidal fuzzy numbers have been used to express uncertainties in Lei et al, 2005; Yuan et al, 2007 have used interval algorithm to deal with the uncertainty of component data to calculate the interval reliability indices. Most of fuzzy methods for reliability evaluation of distribution system are based on fuzzy set theory.

  4. STAR Network Distributed Computer Systems Evaluation Results. (United States)


    image processing systems. Further, because of the small data require- ments a segment of TOTT is a good candidate for VLSI. It can attain the...broadcast capabilities of the distributed architecture to isolate the overhead of accounting and enhacing of fault isolation (see Figure B-1). B-1 The

  5. The Analysis and Design of Distributed Systems

    NARCIS (Netherlands)

    Aksit, Mehmet


    The design of distributed object-oriented systems involves a number of considerations that rarely arise in sequential object-oriented design or in non-object-oriented languages. The tutorial describes analysis and design techniques for data abstraction, inheritance, delegation, persistence,

  6. Gradient remediability in linear distributed parabolic systems ...

    African Journals Online (AJOL)

    The aim of this paper is the introduction of a new concept that concerned the analysis of a large class of distributed parabolic systems. It is the general concept of gradient remediability. More precisely, we study with respect to the gradient observation, the existence of an input operator (gradient efficient actuators) ensuring ...

  7. to medium-sized water distribution systems

    African Journals Online (AJOL)

    Framework for optimizing chlorine dose in small- to medium-sized water distribution systems: A case of a residential neighbourhood in Lahore, Pakistan. ... The bulk decay coefficient (Kb) was determined in the laboratory, whereas the wall decay coefficient (Kw) was estimated by calibrating the simulation results with the ...

  8. A Study of Solar Thermal Propulsion System Enhancement via Thermal Storage and Thermal-electric Conversion (United States)


    material. Molybdenum has a thermal conductivity of 138 W/mK, while rheniums is much lower at 39.6 W/mK 2 . Zirconium Boride (ZrB2) and Hafnium Boride ...14,000 Iridium 77 2739 213 147 $42,000 Niobium 41 2750 323 53.7 $170 Molybdenum 42 2896 390 138 $100 The materials listed in Table 1 do not...this paper, several materials with melting points above 3000 K are boride compounds and several of those that are not borides contain elements which

  9. Integrated thermal treatment system study -- Phase 2 results. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Feizollahi, F.; Quapp, W.J.


    This report presents the second phase of a study on thermal treatment technologies. The study consists of a systematic assessment of nineteen thermal treatment alternatives for the contact-handled mixed low-level waste (MLLW) currently stored in the US Department of Energy complex. The treatment alternatives consist of widely varying technologies for safely destroying the hazardous organic components, reducing the volume, and preparing for final disposal of the MLLW. The alternatives considered in Phase 2 were innovative thermal treatments with nine types of primary processing units. Other variations in the study examined the effect of combustion gas, air pollution control system design, and stabilization technology for the treatment residues. The Phase 1 study examined ten initial thermal treatment alternatives. The Phase 2 systems were evaluated in essentially the same manner as the Phase 1 systems. The alternatives evaluated were: rotary kiln, slagging kiln, plasma furnace, plasma gasification, molten salt oxidation, molten metal waste destruction, steam gasification, Joule-heated vitrification, thermal desorption and mediated electrochemical oxidation, and thermal desorption and supercritical water oxidation. The quantities, and physical and chemical compositions, of the input waste used in the Phase 2 systems differ from those in the Phase 1 systems, which were based on a preliminary waste input database developed at the onset of the Integrated Thermal Treatment System study. The inventory database used in the Phase 2 study incorporates the latest US Department of Energy information. All systems, both primary treatment systems and subsystem inputs, have now been evaluated using the same waste input (2,927 lb/hr). 28 refs., 88 figs., 41 tabs.

  10. Communication Systems and Study Method for Active Distribution Power systems

    DEFF Research Database (Denmark)

    Wei, Mu; Chen, Zhe

    Due to the involvement and evolvement of communication technologies in contemporary power systems, the applications of modern communication technologies in distribution power system are becoming increasingly important. In this paper, the International Organization for Standardization (ISO......) reference seven-layer model of communication systems, and the main communication technologies and protocols on each corresponding layer are introduced. Some newly developed communication techniques, like Ethernet, are discussed with reference to the possible applications in distributed power system....... The suitability of the communication technology to the distribution power system with active renewable energy based generation units is discussed. Subsequently the typical possible communication systems are studied by simulation. In this paper, a novel method of integrating communication system impact into power...

  11. Automation and control of the MMT thermal system (United States)

    Gibson, J. D.; Porter, Dallan; Goble, William


    This study investigates the software automation and control framework for the MMT thermal system. Thermal-related effects on observing and telescope behavior have been considered during the entire software development process. Regression analysis of telescope and observatory subsystem data is used to characterize and model these thermal-related effects. The regression models help predict expected changes in focus and overall astronomical seeing that result from temperature variations within the telescope structure, within the primary mirror glass, and between the primary mirror glass and adjacent air (i.e., mirror seeing). This discussion is followed by a description of ongoing upgrades to the heating, ventilation and air conditioning (HVAC) system and the associated software controls. The improvements of the MMT thermal system have two objectives: 1) to provide air conditioning capabilities for the MMT facilities, and 2) to modernize and enhance the primary mirror (M1) ventilation system. The HVAC upgrade necessitates changes to the automation and control of the M1 ventilation system. The revised control system must factor in the additional requirements of the HVAC system, while still optimizing performance of the M1 ventilation system and the M1's optical behavior. An industry-standard HVAC communication and networking protocol, BACnet (Building Automation and Control network), has been adopted. Integration of the BACnet protocol into the existing software framework at the MMT is discussed. Performance of the existing automated system is evaluated and a preliminary upgraded automated control system is presented. Finally, user interfaces to the new HVAC system are discussed.

  12. Analytic estimation and numerical modeling of actively cooled thermal protection systems with nickel alloys

    Directory of Open Access Journals (Sweden)

    Wang Xinzhi


    Full Text Available Actively cooled thermal protection system has great influence on the engine of a hypersonic vehicle, and it is significant to obtain the thermal and stress distribution in the system. So an analytic estimation and numerical modeling are performed in this paper to investigate the behavior of an actively cooled thermal protection system. The analytic estimation is based on the electric analogy method and finite element analysis (FEA is applied to the numerical simulation. Temperature and stress distributions are obtained for the actively cooled channel walls with three kinds of nickel alloys with or with no thermal barrier coating (TBC. The temperature of the channel wall with coating has no obvious difference from the one with no coating, but the stress with coating on the channel wall is much smaller than that with no coating. Inconel X-750 has the best characteristics among the three Ni-based materials due to its higher thermal conductivity, lower elasticity module and greater allowable stress. Analytic estimation and numerical modeling results are compared with each other and a reasonable agreement is obtained.

  13. A directional wave measurement attack against the Kish key distribution system. (United States)

    Gunn, Lachlan J; Allison, Andrew; Abbott, Derek


    The Kish key distribution system has been proposed as a classical alternative to quantum key distribution. The idealized Kish scheme elegantly promises secure key distribution by exploiting thermal noise in a transmission line. However, we demonstrate that it is vulnerable to nonidealities in its components, such as the finite resistance of the transmission line connecting its endpoints. We introduce a novel attack against this nonideality using directional wave measurements, and experimentally demonstrate its efficacy.

  14. Electron acoustic solitary waves with non-thermal distribution of electrons

    Directory of Open Access Journals (Sweden)

    S. V. Singh


    Full Text Available Electron-acoustic solitary waves are studied in an unmagnetized plasma consisting of non-thermally distributed electrons, fluid cold electrons and ions. The Sagdeev pseudo-potential technique is used to carry out the analysis. The presence of non-thermal electrons modifies the parametric region where electron acoustic solitons can exist. For parameters representative of auroral zone field lines, the electron acoustic solitons do not exist when either α > 0.225 or Tc/Th > 0.142, where α is the fractional non-thermal electron density, and Tc (Th represents the temperature of cold (hot electrons. Further, for these parameters, the simple model predicts negatively charged potential structures. Inclusion of an electron beam in the model may provide the positive potential solitary structures.

  15. Thermal Gradient Data Acquisition System Documentation

    National Research Council Canada - National Science Library

    Walker, Larry D; Robinson, Scott B; Leon, Lisa


    ... that can be recorded in mice. Since acceptable commercial systems are not available, this system was custom-built to acquire data using National Instruments' versatile hardware components and LabVIEW...

  16. Laser spark distribution and ignition system (United States)

    Woodruff, Steven; McIntyre, Dustin L.


    A laser spark distribution and ignition system that reduces the high power optical requirements for use in a laser ignition and distribution system allowing for the use of optical fibers for delivering the low peak energy pumping pulses to a laser amplifier or laser oscillator. An optical distributor distributes and delivers optical pumping energy from an optical pumping source to multiple combustion chambers incorporating laser oscillators or laser amplifiers for inducing a laser spark within a combustion chamber. The optical distributor preferably includes a single rotating mirror or lens which deflects the optical pumping energy from the axis of rotation and into a plurality of distinct optical fibers each connected to a respective laser media or amplifier coupled to an associated combustion chamber. The laser spark generators preferably produce a high peak power laser spark, from a single low power pulse. The laser spark distribution and ignition system has application in natural gas fueled reciprocating engines, turbine combustors, explosives and laser induced breakdown spectroscopy diagnostic sensors.

  17. Application Guide for Thermal Desorption Systems (United States)


    Flue Gas Cleaning System Used Fabric Filter, Sometimes Includes Wet Scrubber Fabric Filter, HEPA Filter, and Carbon Bed Fabric Filter, Carbon Bed...System Afterburner Afterburner Afterburner Typical Flue Gas Cleaning System Used Filter and Carbon Bed Catalytic Oxidizer Carbon Bed Carbon Bed...Average = 8 tph) Off-gas treatment Afterburner Afterburner operating temperature Over 1,500°F Flue gas cleaning system Fabric filter 8.1.3 Treatability

  18. A Novel Silicon Micromachined Integrated MCM Thermal Management System (United States)

    Kazmierczak, M. J.; Henderson, H. T.; Gerner, F. M.


    "Micromachining" is a chemical means of etching three-dimensional structures, typically in single- crystalline silicon. These techniques are leading toward what is coming to be referred to as MEMS (Micro Electro Mechanical Systems), where in addition to the ordinary two-dimensional (planar) microelectronics, it is possible to build three-dimensional n-ticromotors, electrically- actuated raicrovalves, hydraulic systems and much more on the same microchip. These techniques become possible because of differential etching rates of various crystallographic planes and materials used for semiconductor n-ticrofabfication. The University of Cincinnati group in collaboration with Karl Baker at NASA Lewis were the first to form micro heat pipes in silicon by the above techniques. Current work now in progress using MEMS technology is now directed towards the development of the next generation in MCM (Multi Chip Module) packaging. Here we propose to develop a complete electronic thermal management system which will allow densifica6on in chip stacking by perhaps two orders of magnitude. Furthermore the proposed technique will allow ordinary conu-nercial integrated chips to be utilized. Basically, the new technique involves etching square holes into a silicon substrate and then inserting and bonding commercially available integrated chips into these holes. For example, over a 100 1/4 in. by 1 /4 in. integrated chips can be placed on a 4 in. by 4 in. silicon substrate to form a Multi-Chip Module (MCM). Placing these MCM's in-line within an integrated rack then allows for three-diniensional stacking. Increased miniaturization of microelectronic circuits will lead to very high local heat fluxes. A high performance thermal management system will be specifically designed to remove the generated energy. More specifically, a compact heat exchanger with milli / microchannels will be developed and tested to remove the heat through the back side of this MCM assembly for moderate and high

  19. Thermal and chaotic distributions of plasma in laser driven Coulomb explosions of deuterium clusters

    CERN Document Server

    Barbarino, M; Bonasera, A; Lattuada, D; Bang, W; Quevedo, H J; Consoli, F; De Angelis, R; Andreoli, P; Kimura, S; Dyer, G; Bernstein, A C; Hagel, K; Barbui, M; Schmidt, K; Gaul, E; Donovan, M E; Natowitz, J B; Ditmire, T


    In this work we explore the possibility that the motion of the deuterium ions emitted from Coulomb cluster explosions is chaotic enough to resemble thermalization. We analyze the process of nuclear fusion reactions driven by laser-cluster interactions in experiments conducted at the Texas Petawatt laser facility using a mixture of D2+3He and CD4+3He cluster targets. When clusters explode by Coulomb repulsion, the emission of the energetic ions is nearly isotropic. In the framework of cluster Coulomb explosions, we analyze the energy distributions of the ions using a Maxwell- Boltzmann (MB) distribution, a shifted MB distribution (sMB) and the energy distribution derived from a log-normal (LN) size distribution of clusters. We show that the first two distributions reproduce well the experimentally measured ion energy distributions and the number of fusions from d-d and d-3He reactions. The LN distribution is a good representation of the ion kinetic energy distribution well up to high momenta where the noise be...

  20. Development of MCATHAS system of coupled neutronics/thermal-hydraulics in supercritical water reactor

    Energy Technology Data Exchange (ETDEWEB)

    An, P.; Yao, D. [Science and Tech. on Reactor System Design Tech. Laboratory, Chengdu (China)


    The MCATHAS system of coupled neutronics/Thermal-hydraulics in supercritical water reactor is described, which considers the mutual influence between the obvious axial and radial evolution of material temperature, water density and the relative power distribution. This system can obtain the main neutronics and thermal parameters along with burn-up. MCATHAS system is parallel processing coupling. The MCNP code is used for neutronics analysis with the continuous cross section library at any temperature calculated by interpolation algorithm; The sub-channel code ATHAS is for thermal-hydraulics analysis and the ORIGEN Code for burn-up calculation. We validate the code with the assembly of HPLWR and analyze the assembly SCLWR- H. (author)

  1. Distributed parallel messaging for multiprocessor systems (United States)

    Chen, Dong; Heidelberger, Philip; Salapura, Valentina; Senger, Robert M; Steinmacher-Burrow, Burhard; Sugawara, Yutaka


    A method and apparatus for distributed parallel messaging in a parallel computing system. The apparatus includes, at each node of a multiprocessor network, multiple injection messaging engine units and reception messaging engine units, each implementing a DMA engine and each supporting both multiple packet injection into and multiple reception from a network, in parallel. The reception side of the messaging unit (MU) includes a switch interface enabling writing of data of a packet received from the network to the memory system. The transmission side of the messaging unit, includes switch interface for reading from the memory system when injecting packets into the network.

  2. Electrical and Thermal Performance Analysis for a Highly Concentrating Photovoltaic/Thermal System

    Directory of Open Access Journals (Sweden)

    Ning Xu


    Full Text Available A 30 kW highly concentrating photovoltaic/thermal (HCPV/T system has been constructed and tested outdoors. The HCPV/T system consists of 32 modules, each of which consists of point-focus Fresnel lens and triple-junction solar cells with a geometric concentrating ratio of 1090x. The modules are connected to produce both electrical and thermal energy. Performance analysis has been conducted from the viewpoint of thermodynamics. The experimental results show that highest photovoltaic efficiency of 30% and instantaneous thermal efficiency of 30% can be achieved at the same time, which means the total solar energy conversion efficiency of the HCPV/T system is higher than 60%. The photovoltaic efficiency increases with direct irradiance when the direct irradiance is below 580 W/m2, but it remains nearly unchanged when the direct irradiation is higher than 580 W/m2. The instantaneous thermal efficiency decreases during water heating process. However, the electrical performance of the system is not affected obviously by water temperature. Highest exergetic efficiency of 35.4% can be produced by the HCPV/T system. The exergetic efficiency is mainly affected by irradiation level, which is similar to the characteristics of photovoltaic performance.

  3. Reliability evaluation of distribution systems containing renewable distributed generations (United States)

    Alkuhayli, Abdulaziz Abddullah

    Reliability evaluation of distribution networks, including islanded microgrid cases, is presented. The Monte Carlo simulation algorithm is applied to a test network. The network includes three types of distributed energy resources solar photovoltaic (PV), wind turbine (WT) and gas turbine (GT). These distributed generators contribute to supply part of the load during grid-connected mode, but supply the entire load during islanded microgrid operation. PV and WT stochastic models have been used to simulate the randomness of these resources. This study shows that the implementation of distributed generations can improve the reliability of the distribution networks.

  4. Prediction of thermal coagulation from the instantaneous strain distribution induced by high-intensity focused ultrasound (United States)

    Iwasaki, Ryosuke; Takagi, Ryo; Tomiyasu, Kentaro; Yoshizawa, Shin; Umemura, Shin-ichiro


    The targeting of the ultrasound beam and the prediction of thermal lesion formation in advance are the requirements for monitoring high-intensity focused ultrasound (HIFU) treatment with safety and reproducibility. To visualize the HIFU focal zone, we utilized an acoustic radiation force impulse (ARFI) imaging-based method. After inducing displacements inside tissues with pulsed HIFU called the push pulse exposure, the distribution of axial displacements started expanding and moving. To acquire RF data immediately after and during the HIFU push pulse exposure to improve prediction accuracy, we attempted methods using extrapolation estimation and applying HIFU noise elimination. The distributions going back in the time domain from the end of push pulse exposure are in good agreement with tissue coagulation at the center. The results suggest that the proposed focal zone visualization employing pulsed HIFU entailing the high-speed ARFI imaging method is useful for the prediction of thermal coagulation in advance.

  5. Thermal effects in Yb-doped double-cladding Distributed Modal Filtering rod-type fibers

    DEFF Research Database (Denmark)

    Coscelli, Enrico; Poli, Federica; Jørgensen, Mette Marie


    element method. A DMF fiber design, which is single-mode in the 1030 nm–1064 nm region, is considered, and the effects of thermal load on the transmission characteristics are evaluated. Results show a blue-shift of the single-mode window and the single-mode bandwidth narrowing as the absorbed pump power......The effects of thermally-induced refractive index change in Yb-doped Distributed Modal Filtering (DMF) photonic crystal fibers are investigated, where high-order mode suppression is obtained by resonant coupling with high index elements in the cladding. The temperature distribution on the fiber...... cross-section is calculated with an analytical model, for different pump power values. The consequent refractive index change, due to the thermo-optical effect, is applied to the cross-section of the DMF fiber, whose guiding properties are studied with a full-vector modal solver based on the finite...

  6. Synoptic thermal and oceanographic parameter distribution in the New York Bight Apex on June 23, 1977 (United States)

    Johnson, R. W.; Bahn, G. S.; Thomas, J. P.


    Concurrent surface water measurements made from a moving oceanographic research vessel were used to calibrate and interpret remotely sensed data collected over a plume in the New York Bight Apex on June 23, 1977. Multiple regression techniques were used to develop equations to subsequently map synoptic distributions of water quality parameters, chlorophyll A and total suspended matter, in the remotely sensed scene. Thermal (which did not have surface calibration values) and water quality parameter distributions indicated a cold mass of upwelled water in the Bight Apex with an overflowing nutrient-rich warm water plume that originated in the Sandy Hook Bay and flowed south near the New Jersey shoreline. Additional comparison of remotely sensed thermal and optical properties of the water with shipboard measurements indicated that remotely sensed data may be particularly useful for studying physical and biological processes in the top several meters of surface water at the plume boundaries.

  7. Interior thermal insulation systems for historical building envelopes (United States)

    Jerman, Miloš; Solař, Miloš; Černý, Robert


    The design specifics of interior thermal insulation systems applied for historical building envelopes are described. The vapor-tight systems and systems based on capillary thermal insulation materials are taken into account as two basic options differing in building-physical considerations. The possibilities of hygrothermal analysis of renovated historical envelopes including laboratory methods, computer simulation techniques, and in-situ tests are discussed. It is concluded that the application of computational models for hygrothermal assessment of interior thermal insulation systems should always be performed with a particular care. On one hand, they present a very effective tool for both service life assessment and possible planning of subsequent reconstructions. On the other, the hygrothermal analysis of any historical building can involve quite a few potential uncertainties which may affect negatively the accuracy of obtained results.

  8. Analysis of thermal distribution in two end pumping Nd:YAG laser ...

    Indian Academy of Sciences (India)

    Analysis of thermal distribution in two end pumping Nd:YAG laser rod with. Tt(r, z, t) = TL(r, z, t) + Tp(r, t), where Qp(r, t) is the rate of energy generated from the absorbed part of the pump beam per unit volume, QL(r, z, t) is the rate of energy generated from the absorbed part of the amplified laser radiation per unit volume, k is ...

  9. Evaluation of thermal striping for the plugging system in the secondary auxiliary cooling system in JOYO

    Energy Technology Data Exchange (ETDEWEB)

    Isozaki, Kazunori; Ogawa, Tooru; Kubo, Atsuhiko; Aoki, Hiroshi; Ozawa, Kenji [Power Reactor and Nuclear Fuel Development Corp., Oarai, Ibaraki (Japan). Oarai Engineering Center; Sugaya, Kazushi


    Scrutiny based on the convenient evaluation to verify whether we have the place where thermal striping in the pipe confluence part was thought to be a primary factor for the heavy accident or not has been done in JOYO. As the result, the big temperature difference ({Delta}Tin) existed at the inner pipe confluence part of the plugging system in the secondary main and auxiliary cooling system. Therefore, detailed evaluation of thermal striping was needed. With the thermocouples of high response installed, the temperature fluctuation in outer surface of the pipe was measured on the secondary auxiliary plugging system for the reason why the temperature difference ({Delta}Tin) was the biggest. And, the temperature fluctuation in inner surface of the pipe and stress occurring in the pipe plate thickness direction was evaluated by means of non-linear structure analysis system FINAS`. The above-mentioned evaluation results were as follows. (1) The maximum temperature fluctuation occurring in the pipe was always located from the center of inner pipe confluence to 10 mm position of the down-stream side. (2) The maximum temperature fluctuation range was about 33degC in outer surface of the pipe. And, controlling frequency of the temperature fluctuation was 0.04 Hz and 0.09 Hz. (3) Time delay was almost never contained in the temperature fluctuation elements between inner and outer surface of the pipe. And, the big temperature distribution did not occur in the pipe plate thickness direction was confirmed that the big temperature distribution did not occur in the pipe plate thickness direction. The temperature fluctuation range in the pipe inner surface was almost the same as that of the pipe outer surface. It was confirmed that the stress occurring there was enough lowered than the design fatigue limit of SUS304 which was the materials in the confluence part of the plugging system inner part in the secondary main and auxiliary cooling system. (J.P.N.)

  10. Seasonal thermal energy storage in shallow geothermal systems: thermal equilibrium stage

    Directory of Open Access Journals (Sweden)

    Nowamooz Hossein


    Full Text Available This paper is dedicated to the study of seasonal heat storage in shallow geothermal installations in unsaturated soils for which hydrothermal properties such as degree of saturation and thermal conductivity vary with time throughout the profile. In the model, a semi-analytical model which estimates time-spatial thermal conductivity is coupled with a 2D cylindrical heat transfer modeling using finite difference method. The variation of temperature was obtained after 3 heating and cooling cycles for the different types of loads with maximum thermal load of qmax = 15 W.m−1 with variable angular frequency (8 months of heating and 4 months of cooling.and constant angular frequency (6 months of heating and 6 months of cooling to estimate the necessary number of cycles to reach the thermal equilibrium stage. The results show that we approach a thermal equilibrium stage where the same variation of temperature can be observed in soils after several heating and cooling cycles. Based on these simulations, the necessary number of cycles can be related to the total applied energy on the system and the minimum number of cycles is for a system with the total applied energy of 1.9qmax.

  11. CFD Analysis of Thermal Control System Using NX Thermal and Flow (United States)

    Fortier, C. R.; Harris, M. F. (Editor); McConnell, S. (Editor)


    The Thermal Control Subsystem (TCS) is a key part of the Advanced Plant Habitat (APH) for the International Space Station (ISS). The purpose of this subsystem is to provide thermal control, mainly cooling, to the other APH subsystems. One of these subsystems, the Environmental Control Subsystem (ECS), controls the temperature and humidity of the growth chamber (GC) air to optimize the growth of plants in the habitat. The TCS provides thermal control to the ECS with three cold plates, which use Thermoelectric Coolers (TECs) to heat or cool water as needed to control the air temperature in the ECS system. In order to optimize the TCS design, pressure drop and heat transfer analyses were needed. The analysis for this system was performed in Siemens NX Thermal/Flow software (Version 8.5). NX Thermal/Flow has the ability to perform 1D or 3D flow solutions. The 1D flow solver can be used to represent simple geometries, such as pipes and tubes. The 1D flow method also has the ability to simulate either fluid only or fluid and wall regions. The 3D flow solver is similar to other Computational Fluid Dynamic (CFD) software. TCS performance was analyzed using both the 1D and 3D solvers. Each method produced different results, which will be evaluated and discussed.

  12. Structural design aspects of reusable surface insulation thermal protection systems. (United States)

    Michalak, R. J.; Hess, T. E.; Gluck, R. L.


    Low density fiber ceramic materials coated with refractory ceramics meet the requirements of reusable low weight thermal protection systems. The structural characteristics of this class of material impose unique design and analysis requirements on the application to spacecraft structural elements. Finite element type stress analysis techniques are required to adequately predict the structural response of the system. Parametric analyses have been performed to determine the response of the system to variations in geometry, and to thermal and structural load conditions. Sensitivity of coating, insulation and attachment stresses are presented and critical failure modes are identified.

  13. Alternative High Performance Polymers for Ablative Thermal Protection Systems (United States)

    Boghozian, Tane; Stackpoole, Mairead; Gonzales, Greg


    Ablative thermal protection systems are commonly used as protection from the intense heat during re-entry of a space vehicle and have been used successfully on many missions including Stardust and Mars Science Laboratory both of which used PICA - a phenolic based ablator. Historically, phenolic resin has served as the ablative polymer for many TPS systems. However, it has limitations in both processing and properties such as char yield, glass transition temperature and char stability. Therefore alternative high performance polymers are being considered including cyanate ester resin, polyimide, and polybenzoxazine. Thermal and mechanical properties of these resin systems were characterized and compared with phenolic resin.

  14. Design and performance of Skylab thermal/environmental control system (United States)

    Hopson, G. D.; Littles, J. W.; Patterson, W. C.


    The function of the thermal/environmental control systems was to provide a comfortable thermal environment for the crew, to cool electronic components, to supply a controlled oxygen/nitrogen atmosphere, and to remove moisture, carbon dioxide, odors, and trace contaminants from the atmosphere. A separate refrigeration system was used to chill and freeze food and biomedical samples and to provide cold water for drinking. This paper describes system design and compares in-flight performance to preflight predictions. A discussion of in-flight anomalies and corrective actions is also included.

  15. Finite element analysis of thermal stress distribution in different restorative materials used in class V cavities. (United States)

    Guler, M S; Guler, C; Cakici, F; Cakici, E B; Sen, S


    Cervical lesions are restored with class V preparation. The aim of this study was to use a three-dimensional finite element method to carry out a thermal analysis of the temperature and stress distributions of three different restorative materials used for class V cavities of maxillary molar teeth. A maxillary left first molar tooth was modeled and a class V cavity was prepared on the cervical 1/3 of the buccal surface. This cavity was restored with three different materials (Group I: Resin composite, Group II: Glass ionomer cement, and Group III: Amalgam). Loads of 400 N were applied at an angle of 90° to the longitudinal axis of the tooth on the restorative material at 5 and 55°C temperatures. Von Mises and thermal stress distributions were evaluated. In all groups, the von Mises stress values increased with temperature. The highest von Mises stress distribution was observed at 55°C in Group II (144.53 MPa). The lowest von Mises stress distribution was observed at 5°C in Group III (70.81 MPa). Amalgam is the most suitable restorative material for class V restorations because of minimal stress distribution.

  16. Thermal Characterization of Molten Salt Systems

    Energy Technology Data Exchange (ETDEWEB)

    Toni Y. Gutknecht; Guy L. Fredrickson


    The phase stability of molten salts in an electrorefiner (ER) may be adversely affected by the buildup of sodium, fission products, and transuranics in the electrolyte. Potential situations that need to be avoided are the following: (1) salt freezing due to an unexpected change in the liquidus temperature, (2) phase separation or non-homogeneity of the molten salt due to the precipitation of solids or formation of immiscible liquids, and (3) any mechanism that can result in the separation and concentration of fissile elements from the molten salt. Any of these situations would result in an off-normal condition outside the established safety basis for electrorefiner (ER) operations. The stability (and homogeneity) of the phases can potentially be monitored through the thermal characterization of the salts, which can be a function of impurity concentration. This report describes the experimental results of typical salts compositions, which consist of chlorides of potassium, lithium, strontium, samarium, praseodymium, lanthanum, barium, cerium, cesium, neodymium, sodium and gadolinium chlorides as a surrogate for both uranium and plutonium, used for the processing of used nuclear fuels.

  17. Monitoring of Thermal Protection Systems Using Robust Self-Organizing Optical Fiber Sensing Networks (United States)

    Richards, Lance


    The general aim of this work is to develop and demonstrate a prototype structural health monitoring system for thermal protection systems that incorporates piezoelectric acoustic emission (AE) sensors to detect the occurrence and location of damaging impacts, and an optical fiber Bragg grating (FBG) sensor network to evaluate the effect of detected damage on the thermal conductivity of the TPS material. Following detection of an impact, the TPS would be exposed to a heat source, possibly the sun, and the temperature distribution on the inner surface in the vicinity of the impact measured by the FBG network. A similar procedure could also be carried out as a screening test immediately prior to re-entry. The implications of any detected anomalies in the measured temperature distribution will be evaluated for their significance in relation to the performance of the TPS during re-entry. Such a robust TPS health monitoring system would ensure overall crew safety throughout the mission, especially during reentry

  18. Representation of chromatic distribution for lighting system (United States)

    Rossi, Maurizio; Musante, Fulvio


    For the luminaire manufacturer, the measurement of the lighting intensity distribution (LID) emitted by lighting fixture is based on photometry. So light is measured as an achromatic value of intensity and there is no the possibility to discriminate the measurement of white vs. colored light. At the Laboratorio Luce of Politecnico di Milano a new instrument for the measurement of spectral radiant intensities distribution for lighting system has been built: the goniospectra- radiometer. This new measuring tool is based on a traditional mirror gonio-photometer with a CCD spectraradiometer controlled by a PC. Beside the traditional representation of photometric distribution we have introduced a new representation where, in addition to the information about the distribution of luminous intensity in space, new details about the chromaticity characteristic of the light sources have been implemented. Some of the results of this research have been applied in developing and testing a new line of lighting system "My White Light" (the research project "Light, Environment and Humans" funded in the Italian Lombardy region Metadistretti Design Research Program involving Politecnico di Milano, Artemide, Danese, and some other SME of the Lighting Design district), giving scientific notions and applicative in order to support the assumption that colored light sources can be used for the realization of interior luminaries that, other than just have low power consumption and long life, may positively affect the mood of people.

  19. Building Climate Energy Management in Smart Thermal Grids via Aquifer Thermal Energy Storage Systems

    NARCIS (Netherlands)

    Rostampour, Vahab; Jaxa-Rozen, M.; Bloemendal, J.M.; Keviczky, T.


    This paper proposes a building energy management framework, described by mixed logical dynamical systems due to operating constraints and logic rules, together with an aquifer thermal energy storage (ATES) model. We develop a deterministic model predictive control strategy to meet building

  20. Review of the integrated thermal and nonthermal treatment system studies

    Energy Technology Data Exchange (ETDEWEB)



    This report contains a review and evaluation of three systems analysis studies performed by LITCO on integrated thermal treatment systems and integrated nonthermal treatment systems for the remediation of mixed low-level waste stored throughout the US Department of Energy weapons complex. The review was performed by an independent team of nine researchers from the Energy and Environmental Research Center, Science Applications International Corporation, the Waste Policy Institute, and Virginia Tech. The three studies reviewed were as follows: Integrated Thermal Treatment System Study, Phase 1--issued July 1994; Integrated Thermal Treatment System Study, Phase 2--issued February 1996; and Integrated Nonthermal Treatment System Study--drafted March 1996. The purpose of this review was to (1) determine whether the assumptions of the studies were adequate to produce an unbiased review of both thermal and nonthermal systems, (2) to identify the critical areas of the studies that would benefit from further investigation, and (3) to develop a standard template that could be used in future studies to assure a sound application of systems engineering.

  1. Robust Reconfiguration of A Distribution System

    Energy Technology Data Exchange (ETDEWEB)

    Moradzadeh, Benyamin [University of Tennessee, Knoxville (UTK); Tomsovic, Kevin [University of Tennessee, Knoxville (UTK)


    In this paper, a robust reconfiguration approach based on Mixed Integer Programming (MIP) is proposed to minimize loss in distribution systems. A Depth-First Search (DFS) algorithm to enumerate possible loops provides radiality constraint. This provides a general solution to the radiality constraint for distribution system reconfiguration/expansion problems. Still, imprecision and ambiguity in net loads, i.e. load minus renewable generation, due to lack of sufficient measurements and high utilization of demand response programs and renewable resources, creates challenges for effective reconfiguration. Deterministic optimization of reconfiguration may no lead to optimal/feasible results. Two methods to address these uncertainties are introduced in this paper: one, based on a stochastic MIP (SMIP) formulation and two, based on a fuzzy MIP (FMIP) formulation. Case studies demonstrate the robustness and efficiency of the proposed reconfiguration methods.

  2. SORCE: A design tool for solar organic Rankine cycle systems in distributed generation applications


    Orosz, Matthew; Quoilin, Sylvain; Hemond, Harold


    Recent interest in small-scale solar thermal combined heat and power (CHP) power systems has coincided with demand growth for distributed electricity supplies in areas poorly served by centralized power stations. One potential technical approach to meeting this demand is the parabolic trough solar thermal collector coupled with an organic Rankine cycle (ORC) heat engine. Much existing research touches on aspects of the underlying physics and mechanics of this technology, but a holistic treatm...

  3. 47 CFR 73.6023 - Distributed transmission systems. (United States)


    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Distributed transmission systems. 73.6023... distributed transmission system. ... RADIO BROADCAST SERVICES Class A Television Broadcast Stations § 73.6023 Distributed transmission...

  4. Non-Thermal Plasma System Development for CIDI Exhaust Aftertreatment

    Energy Technology Data Exchange (ETDEWEB)

    Balmer, M. Lou (Pacific Northwest National Laboratory (PNNL)); Tonkyn, Russell (Battelle Pacific Northwest Laboratories (BPNL)); Maupin, Gary; Yoon, Steven; Kolwaite, Ana (PNNL); Barlow, Stephen (BPNL); Domingo, Norberto; Storey, John M. (Oak Ridge National Laboratory); Hoard, John Wm. (Ford Research Laboratory); Howden, Ken (U.S. Dept. of Energy)


    There is a need for an efficient, durable technology to reduce NOx emissions from oxidative exhaust streams such as those produced by compression-ignition, direct injection (CIDI) diesel or lean-burn gasoline engines. A partnership formed between the DOE Office of Advanced Automotive Technology, Pacific Northwest National Laboratory, Oak Ridge National Laboratory and the USCAR Low Emission Technologies Research and Development Partnership is evaluating the effectiveness of a non-thermal plasma in conjunction with catalytic materials to mediate NOx and particulate emissions from diesel fueled light duty (CIDI) engines. Preliminary studies showed that plasma-catalyst systems could reduce up to 70% of NOx emissions at an equivalent cost of 3.5% of the input fuel in simulated diesel exhaust. These studies also showed that the type and concentration of hydrocarbon play a key role in both the plasma gas phase chemistry and the catalyst surface chemistry. More recently, plasma/catalyst systems have been evaluated for NOx reduction and particulate removal on a CIDI engine. Performance results for select plasma-catalyst systems for both simulated and actual CIDI exhaust will be presented. The effect of NOx and hydrocarbon concentration on plasma-catalyst performance will also be shown. SAE Paper SAE-2000-01-1601 {copyright} 2000 SAE International. This paper is published on this website with permission from SAE International. As a user of this website, you are permitted to view this paper on-line, download this pdf file and print one copy of this paper at no cost for your use only. The downloaded pdf file and printout of this SAE paper may not be copied, distributed or forwarded to others or for the use of others.

  5. Byzantine Failure Detection for Dynamic Distributed Systems


    Santos De Lima, Murilo; Greve, Fabiola; Arantes, Luciana; Sens, Pierre


    Byzantine failure detectors provide an elegant abstraction for implementing Byzantine fault tolerance. However, as far as we know, there is no general solution for this problem in a dynamic distributed system over wireless networks with unknown membership. This paper presents thus a first Byzantine failure detector for this context. The protocol has the interesting feature to be time-free, that is, it does not rely on timers to detect omission failures. This characteristic favors its scalabil...

  6. Byzantine-resilient distributed computing systems


    Patnaik, LM; S.Balaji


    This paper is aimed at reviewing the notion of Byzantine-resilient distributed computing systems, the relevant protocols and their possible applications as reported in the literature. The three agreement problems, namely, the consensus problem, the interactive consistency problem, and the generals problem have been discussed. Various agreement protocols for the Byzantine generals problem have been summarized in terms of their performance and level of fault-tolerance. The three classes of Byza...

  7. DNA - A Thermal Energy System Simulator

    DEFF Research Database (Denmark)


    DNA is a general energy system simulator for both steady-state and dynamic simulation. The program includes a * component model library * thermodynamic state models for fluids and solid fuels and * standard numerical solvers for differential and algebraic equation systems and is free and portable...... (open source, open use, standard FORTRAN77). DNA is text-based using whichever editor, you like best. It has been integerated with the emacs editor. This is usually available on unix-like systems. for windows we recommend the Installation instructions for windows: First install emacs and then run...


    Pittman, C. M.


    This program performs a one-dimensional numerical analysis of the transient thermal response of multi-layer insulative systems. The analysis can determine the temperature distribution through a system consisting of from one to four layers, one of which can be an air gap. Concentrated heat sinks at any interface can be included. The computer program based on the analysis will determine the thickness of a specified layer that will satisfy a temperature limit criterion at any point in the insulative system. The program will also automatically calculate the thickness at several points on a system and determine the total system mass. This program was developed as a tool for designing thermal protection systems for high-speed aerospace vehicles but could be adapted to many areas of industry involved in thermal insulation systems. In this package, the equations describing the transient thermal response of a system are developed. The governing differential equation for each layer and boundary condition are put in finite-difference form using a Taylor's series expansion. These equations yield an essentially tridiagonal matrix of unknown temperatures. A procedure based on Gauss' elimination method is used to solve the matrix. This program is written in FORTRAN IV for the CDC RUN compiler and has been implemented on a CDC 6000 series machine operating under SCOPE 3.0. This program requires a minimum of 44K (octal) of 60 bit words of memory.

  9. System Design Description PFP Thermal Stabilization

    Energy Technology Data Exchange (ETDEWEB)



    DOE has authorized in their letter of August 2, 1999, the operation of these three furnaces, quote ''Operation of the three uncompleted muffle furnaces (No.3, No.4, and No.5) located in Room 235B is authorized, using the same feed charge limits as the two existing furnaces (No.1, and No.2) located in Room 230C,''. The above statement incorrectly refers to Room 230C whereas the correct location is Room 230A. The current effort is directed to initiate the operation and to complete the design activities DOE authorized the operation of the furnaces based on their Safety Evaluation Report (SER). Based on analogy and the principle of similarity, the risks and consequences of accidents both onsite and offsite due to operation of three furnaces are not significantly larger than those already evaluated with the two operating furnaces. Thermal stabilization operations and the material of feed for furnaces in Glovebox HA-21 I are essentially the same as those currently being stabilized in furnaces in Glovebox HC-21 C. Therefore the accident analysis has utilized identical accident scenarios in evaluation and no additional failure modes are introduced by HA-21 I muffle furnace operation that would enhance the consequences of accidents. Authorization Basis documents as referenced below (PFP FSAR and DOE Letter authorizing the operation) appear to contradict each other, i.e. one allows and authorizes the operation and the other imposes the restriction on the operation. The purpose of the PFP FSAR restrictions was to review thoroughly the design and installation of three furnaces and perform acceptance testing before approving the startup for operation. With the experience of operating the two furnaces in Glovebox HC-21C, and the knowledge of risks and hazards the facility operation, the plant is adequately prepared to operate these additional furnaces. ECN 653595 has been prepared to incorporate operation of the muffle furnaces in Glovebox HA-21 I into the

  10. Evaluation of an improved air distribution system for aircraft cabin

    DEFF Research Database (Denmark)

    Pang, Liping; Xu, Jie; Fang, Lei


    An improved air distribution system for aircraft cabin was proposed in this paper. Personalized outlets were introduced and placed at the bottom of the baggage hold. Its ratio of fresh air to recirculation air and the conditioned temperature of different types of inlets were also designed carefully...... to meet the goals of high air quality, thermal comfort and energy saving. Some experiments were conducted to evaluate and compare its performances with two other systems. First the Flow Visualization with Green Laser (FVGL) technology was used to analyze the air flow. The top-in-side bottom-out pattern...... results suggest that personalized inlet should be designed to adjust its supply air angle according to the height of the passenger's face to provide a higher fresh air utilization effectiveness and better air quality for passengers in the improved pattern. Some simulations revealed that the improved...

  11. System to Measure Thermal Conductivity and Seebeck Coefficient for Thermoelectrics (United States)

    Kim, Hyun-Jung; Skuza, Jonathan R.; Park, Yeonjoon; King, Glen C.; Choi, Sang H.; Nagavalli, Anita


    The Seebeck coefficient, when combined with thermal and electrical conductivity, is an essential property measurement for evaluating the potential performance of novel thermoelectric materials. However, there is some question as to which measurement technique(s) provides the most accurate determination of the Seebeck coefficient at elevated temperatures. This has led to the implementation of nonstandardized practices that have further complicated the confirmation of reported high ZT materials. The major objective of the procedure described is for the simultaneous measurement of the Seebeck coefficient and thermal diffusivity within a given temperature range. These thermoelectric measurements must be precise, accurate, and reproducible to ensure meaningful interlaboratory comparison of data. The custom-built thermal characterization system described in this NASA-TM is specifically designed to measure the inplane thermal diffusivity, and the Seebeck coefficient for materials in the ranging from 73 K through 373 K.

  12. ISS-CREAM Thermal and Fluid System Design and Analysis (United States)

    Thorpe, Rosemary S.


    Thermal and Fluids Analysis Workshop (TFAWS), Silver Spring MD NCTS 21070-15. The ISS-CREAM (Cosmic Ray Energetics And Mass for the International Space Station) payload is being developed by an international team and will provide significant cosmic ray characterization over a long time frame. Cold fluid provided by the ISS Exposed Facility (EF) is the primary means of cooling for 5 science instruments and over 7 electronics boxes. Thermal fluid integrated design and analysis was performed for CREAM using a Thermal Desktop model. This presentation will provide some specific design and modeling examples from the fluid cooling system, complex SCD (Silicon Charge Detector) and calorimeter hardware, and integrated payload and ISS level modeling. Features of Thermal Desktop such as CAD simplification, meshing of complex hardware, External References (Xrefs), and FloCAD modeling will be discussed.

  13. Solar thermal power systems. Annual technical progress report, FY 1979

    Energy Technology Data Exchange (ETDEWEB)

    Braun, Gerald W.


    The Solar Thermal Power Systems Program is the key element in the national effort to establish solar thermal conversion technologies within the major sectors of the national energy market. It provides for the development of concentrating mirror/lens heat collection and conversion technologies for both central and dispersed receiver applications to produce electricity, provide heat at its point of use in industrial processes, provide heat and electricity in combination for industrial, commercial, and residential needs, and ultimately, drive processes for production of liquid and gaseous fuels. This report is the second Annual Technical Progress Report for the Solar Thermal Power Systems Program and is structured according to the organization of the Solar Thermal Power Systems Program on September 30, 1979. Emphasis is on the technical progress of the projects rather than on activities and individual contractor efforts. Each project description indicates its place in the Solar Thermal Power Systems Program, a brief history, the significant achievements and real progress during FY 1979, also future project activities as well as anticipated significant achievements are forecast. (WHK)

  14. Switching in electrical transmission and distribution systems

    CERN Document Server

    Smeets, René; Kapetanovic, Mirsad; Peelo, David F; Janssen, Anton


    Switching in Electrical Transmission and Distribution Systems presents the issues and technological solutions associated with switching in power systems, from medium to ultra-high voltage. The book systematically discusses the electrical aspects of switching, details the way load and fault currents are interrupted, the impact of fault currents, and compares switching equipment in particular circuit-breakers. The authors also explain all examples of practical switching phenomena by examining real measurements from switching tests. Other highlights include: up to date commentary on new develo

  15. Review of the integrated thermal and nonthermal treatment system studies

    Energy Technology Data Exchange (ETDEWEB)

    Durrani, H.A.; Schmidt, L.J.; Erickson, T.A.; Sondreal, E.A.; Erjavec, J.; Steadman, E.N.; Fabrycky, W.J.; Wilson, J.S.; Musich, M.A.


    This report analyzes three systems engineering (SE) studies performed on integrated thermal treatment systems (ITTSs) and integrated nonthermal treatment systems (INTSs) for the remediation of mixed low-level waste (MLLW) stored throughout the US Department of Energy (DOE) weapons complex. The review was performed by an independent team of nine researchers from the Energy and Environmental Research Center (EERC), Science Applications International Corporation (SAIC), the Waste Policy Institute (WPI), and Virginia Tech (VT). The three studies reviewed were as follows: Integrated Thermal Treatment System Study, Phase 1--issued July 1994; Integrated Thermal Treatment System Study, Phase 2--issued February 1996; and Integrated Nonthermal Treatment System Study--drafted March 1996. The purpose of this review was to (1) determine whether the assumptions taken in the studies might bias the resulting economic evaluations of both thermal and nonthermal systems, (2) identify the critical areas of the studies that would benefit from further investigation, and (3) develop a standard template that could be used in future studies to produce sound SE applications.

  16. Approach to thermal equilibrium of macroscopic quantum systems. (United States)

    Goldstein, Sheldon; Lebowitz, Joel L; Mastrodonato, Christian; Tumulka, Roderich; Zanghi, Nino


    We consider an isolated macroscopic quantum system. Let H be a microcanonical "energy shell," i.e., a subspace of the system's Hilbert space spanned by the (finitely) many energy eigenstates with energies between E and E+deltaE . The thermal equilibrium macrostate at energy E corresponds to a subspace H(eq) of H such that dim H(eq)/dim H is close to 1. We say that a system with state vector psi is the element of H is in thermal equilibrium if psi is "close" to H(eq). We show that for "typical" Hamiltonians with given eigenvalues, all initial state vectors psi(0) evolve in such a way that psi(t) is in thermal equilibrium for most times t. This result is closely related to von Neumann's quantum ergodic theorem of 1929.

  17. Energy demand and thermal comfort of HVAC systems with thermally activated building systems as a function of user profile

    Directory of Open Access Journals (Sweden)

    Pałaszyńska Katarzyna


    Full Text Available Thermally Activated Building Systems (TABS are a way to use building structure as a thermal energy storage. As a result, renewable energy sources may be used more efficiently. The paper presents numerical analysis of a HVAC system with TABS energy demand and indoor thermal comfort of a representative room in a non-residential building (governmental, commercial, educational. The purpose of analysis is to investigate the influence of a user profile on system performance. The time span of the analysis is one year – a typical meteorological year. The model was prepared using a generally accepted simulation tool – TRNSYS 17. The results help to better understand the interaction of a user profile with TABS. Therefore they are important for the development of optimal control algorithms for energy efficient buildings equipped with such systems.

  18. Energy demand and thermal comfort of HVAC systems with thermally activated building systems as a function of user profile (United States)

    Pałaszyńska, Katarzyna; Bandurski, Karol; Porowski, Mieczysław


    Thermally Activated Building Systems (TABS) are a way to use building structure as a thermal energy storage. As a result, renewable energy sources may be used more efficiently. The paper presents numerical analysis of a HVAC system with TABS energy demand and indoor thermal comfort of a representative room in a non-residential building (governmental, commercial, educational). The purpose of analysis is to investigate the influence of a user profile on system performance. The time span of the analysis is one year - a typical meteorological year. The model was prepared using a generally accepted simulation tool - TRNSYS 17. The results help to better understand the interaction of a user profile with TABS. Therefore they are important for the development of optimal control algorithms for energy efficient buildings equipped with such systems.

  19. Disinfection of water distribution systems for Legionella. (United States)

    Lin, Y S; Stout, J E; Yu, V L; Vidic, R D


    Hospital-acquired legionnaires' disease arises from the presence of Legionella in hospital water systems. Legionella not only persists in hot water tanks but is also found in the biofilm throughout the entire water distribution system. Conditions within water systems that promote Legionella colonization include water temperature, configuration and age of the hot water tank, physicochemical constituents of the water, plumbing materials, and commensal microflora. Hospital-acquired legionnaires' disease has been prevented by instituting control measures directed at the water distribution system. These include superheat-and-flush, copper/silver ionization, ultraviolet light, instantaneous heating systems, and hyperchlorination. Each of the above disinfection methods has been proven to be effective in the short-term, but long-term efficacy has been difficult due to limitations associated with each method. The complexities of Legionella disinfection, including advantages and disadvantages of each method, are reviewed. A successful Legionella prevention program requires cooperation and communication among hospital administrative personnel, engineers, and infection control staff. Routine environmental surveillance cultures for Legionella are the critical component for successful long-term disinfection. Culture results document the efficacy of the disinfection method and alert the hospital staff to consider Legionella in hospitalized patients with pneumonia.

  20. Computing Wigner distributions and time correlation functions using the quantum thermal bath method: application to proton transfer spectroscopy. (United States)

    Basire, Marie; Borgis, Daniel; Vuilleumier, Rodolphe


    Langevin dynamics coupled to a quantum thermal bath (QTB) allows for the inclusion of vibrational quantum effects in molecular dynamics simulations at virtually no additional computer cost. We investigate here the ability of the QTB method to reproduce the quantum Wigner distribution of a variety of model potentials, designed to assess the performances and limits of the method. We further compute the infrared spectrum of a multidimensional model of proton transfer in the gas phase and in solution, using classical trajectories sampled initially from the Wigner distribution. It is shown that for this type of system involving large anharmonicities and strong nonlinear coupling to the environment, the quantum thermal bath is able to sample the Wigner distribution satisfactorily and to account for both zero point energy and tunneling effects. It leads to quantum time correlation functions having the correct short-time behavior, and the correct associated spectral frequencies, but that are slightly too overdamped. This is attributed to the classical propagation approximation rather than the generation of the quantized initial conditions themselves.

  1. Smart Operations in Distributed Energy Resources System (United States)

    Wei, Li; Jie, Shu; Zhang-XianYong; Qing, Zhou

    Smart grid capabilities are being proposed to help solve the challenges concerning system operations due to that the trade-offs between energy and environmental needs will be constantly negotiated while a reliable supply of electricity needs even greater assurance in case of that threats of disruption have risen. This paper mainly explores models for distributed energy resources system (DG, storage, and load),and also reviews the evolving nature of electricity markets to deal with this complexity and a change of emphasis on signals from these markets to affect power system control. Smart grid capabilities will also impact reliable operations, while cyber security issues must be solved as a culture change that influences all system design, implementation, and maintenance. Lastly, the paper explores significant questions for further research and the need for a simulation environment that supports such investigation and informs deployments to mitigate operational issues as they arise.

  2. Security of practical quantum key distribution systems

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Nitin


    This thesis deals with practical security aspects of quantum key distribution (QKD) systems. At the heart of the theoretical model of any QKD system lies a quantum-mechanical security proof that guarantees perfect secrecy of messages - based on certain assumptions. However, in practice, deviations between the theoretical model and the physical implementation could be exploited by an attacker to break the security of the system. These deviations may arise from technical limitations and operational imperfections in the physical implementation and/or unrealistic assumptions and insufficient constraints in the theoretical model. In this thesis, we experimentally investigate in depth several such deviations. We demonstrate the resultant vulnerabilities via proof-of-principle attacks on a commercial QKD system from ID Quantique. We also propose countermeasures against the investigated loopholes to secure both existing and future QKD implementations.

  3. Distributed Computation in a Quadrupedal Robotic System

    Directory of Open Access Journals (Sweden)

    Daniel Kuehn


    Full Text Available Today's and future space missions (will have to deal with increasing requirements regarding autonomy and flexibility in the locomotor system. To cope with these requirements, a higher bandwidth for sensor information is needed. In this paper, a robotic system is presented that is equipped with artificial feet and a spine incorporating increased sensing capabilities for walking robots. In the proposed quadrupedal robotic system, the front and rear parts are connected via an actuated spinal structure with six degrees of freedom. In order to increase the robustness of the system's locomotion in terms of traction and stability, a foot-like structure equipped with various sensors has been developed. In terms of distributed local control, both structures are as self-contained as possible with regard to sensing, sensor preprocessing, control and communication. This allows the robot to respond rapidly to occurring events with only minor latency.

  4. States of Cybersecurity: Electricity Distribution System Discussions

    Energy Technology Data Exchange (ETDEWEB)

    Pena, Ivonne [National Renewable Energy Lab. (NREL), Golden, CO (United States); Ingram, Michael [National Renewable Energy Lab. (NREL), Golden, CO (United States); Martin, Maurice [National Renewable Energy Lab. (NREL), Golden, CO (United States)


    State and local entities that oversee the reliable, affordable provision of electricity are faced with growing and evolving threats from cybersecurity risks to our nation's electricity distribution system. All-hazards system resilience is a shared responsibility among electric utilities and their regulators or policy-setting boards of directors. Cybersecurity presents new challenges and should be a focus for states, local governments, and Native American tribes that are developing energy-assurance plans to protect critical infrastructure. This research sought to investigate the implementation of governance and policy at the distribution utility level that facilitates cybersecurity preparedness to inform the U.S. Department of Energy (DOE), Office of Energy Policy and Systems Analysis; states; local governments; and other stakeholders on the challenges, gaps, and opportunities that may exist for future analysis. The need is urgent to identify the challenges and inconsistencies in how cybersecurity practices are being applied across the United States to inform the development of best practices, mitigations, and future research and development investments in securing the electricity infrastructure. By examining the current practices and applications of cybersecurity preparedness, this report seeks to identify the challenges and persistent gaps between policy and execution and reflect the underlying motivations of distinct utility structures as they play out at the local level. This study aims to create an initial baseline of cybersecurity preparedness within the distribution electricity sector. The focus of this study is on distribution utilities not bound by the cybersecurity guidelines of the North American Electric Reliability Corporation (NERC) to examine the range of mechanisms taken by state regulators, city councils that own municipal utilities, and boards of directors of rural cooperatives.

  5. Tehachapi solar thermal system first annual report

    Energy Technology Data Exchange (ETDEWEB)

    Rosenthal, A. [Southwest Technology Development Inst., Las Cruces, NM (US)


    The staff of the Southwest Technology Development Institute (SWTDI), in conjunction with the staff of Industrial Solar Technology (IST), have analyzed the performance, operation, and maintenance of a large solar process heat system in use at the 5,000 inmate California Correctional Institution (CCI) in Tehachapi, CA. This report summarizes the key design features of the solar plant, its construction and maintenance histories through the end of 1991, and the performance data collected at the plant by a dedicated on-site data acquisition system (DAS).

  6. Examination of the CLIC drive beam pipe design for thermal distortion caused by distributed beam loss

    CERN Document Server

    Johnson, C D


    Beam transport programs are widely used to estimate the distribution of power deposited in accelerator structures by particle beams, either intentionally as for targets or beam dumps or accidentally owing to beam loss incidents. While this is usually adequate for considerations of radiation safety, it does not reveal the expected temperature rise and its effect on structural integrity. To find this, thermal diffusion must be taken into account, requiring another step in the analysis. The method that has been proposed is to use the output of a transport program, perhaps modified, as input for a finite element analysis program that can solve the thermal diffusion equation. At CERN, the design of the CLIC drive beam pipe has been treated in this fashion. The power distribution produced in the walls by a distributed beam loss was found using the electron gamma shower code EGS4. The distribution of power density was then used to form the input for the finite element analysis program ANSYS, which was able to find t...

  7. Advanced concepts in ground thermal energy storage systems (United States)

    Woods, Kevin David

    In recent years, ground thermal energy storage has become a topic of interest in the energy community for solar thermal energy storage systems, ground sourced heat pump systems, and data center thermal management systems due to an increase in the energy efficiency of such systems utilizing the ground as a thermal reservoir. The most common method for transferring thermal energy to the ground formation is the geothermal borehole. This dissertation presents the state of the art in geothermal borehole modeling and derives novel analytical functions to model advanced concepts concerning their operation. The novel solutions derived allow a geothermal borehole designer to better understand and design ground energy storage systems. The state of the art in geothermal borehole modeling is the stationary line source solution which is limited to boreholes operating without groundwater flow. Novel solutions for modeling a geothermal borehole with groundwater advection are presented through derivation of a transient moving line source solution as well as a transient moving cylindrical surface source solution. These solutions are applied to model a specific type of open loop geothermal borehole called a standing column well with groundwater advection and are compared to empirical and numerical data for validation. The dissertation then moves into derivation of a property determination method for geothermal boreholes with groundwater advection. The traditional property determination method used to obtain ground formation properties is based on the stationary transient line source method and fails in the presence of groundwater flow. The proposed novel property determination method calculates the thermal conductivity, thermal diffusivity, and superficial flow velocity of groundwater within a ground formation. These methods and solutions are novel tools allowing for geothermal borehole designers to grasp a better understanding of the systems they are designing as well as open other

  8. Thermal Design of a Protomodel Space Infrared Cryogenic System

    Directory of Open Access Journals (Sweden)

    Hyung Suk Yang


    Full Text Available A Protomodel Space Infrared Cryogenic System (PSICS cooled by a stirling cryocooler has been designed. The PSICS has an IR sensor inside the cold box which is cooled by a stirling cryocooler with refrigeration capacity of 500mW at 80K in a vacuum vessel. It is important to minimize the heat load so that the background thermal noise can be reduced. In order to design the cryogenic system with low heat load and to reduce the remained heat load, we have performed numerical analyses. In this paper, we present the design factors and the results obtained by the thermal analysis of the PSICS.

  9. Thermal Battery Systems for Ordnance Fuzing (United States)


    unanswered. the light of current knowledge and re- For example, recent termination of a CaCrO 4 quirements may be helpiul. manufacturing few elec- .ind b king proceo , res.48 The DEB pellets are trochemical systems have been used or uAsuall) made from a homog( ieous powder, studied

  10. Electric vehicles batteries thermal management systems employing phase change materials (United States)

    Ianniciello, Lucia; Biwolé, Pascal Henry; Achard, Patrick


    Battery thermal management is necessary for electric vehicles (EVs), especially for Li-ion batteries, due to the heat dissipation effects on those batteries. Usually, air or coolant circuits are employed as thermal management systems in Li-ion batteries. However, those systems are expensive in terms of investment and operating costs. Phase change materials (PCMs) may represent an alternative which could be cheaper and easier to operate. In fact, PCMs can be used as passive or semi-passive systems, enabling the global system to sustain near-autonomous operations. This article presents the previous developments introducing PCMs for EVs battery cooling. Different systems are reviewed and solutions are proposed to enhance PCMs efficiency in those systems.

  11. FRIB Cryogenic Distribution System and Status

    Energy Technology Data Exchange (ETDEWEB)

    Ganni, Venkatarao [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Dixon, Kelly D. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Laverdure, Nathaniel A. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Yang, Shuo [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Nellis, Timothy [Michigan State Univ., East Lansing, MI (United States); Jones, S. [Michigan State Univ., East Lansing, MI (United States); Casagrande, Fabio [Michigan State Univ., East Lansing, MI (United States)


    The MSU-FRIB cryogenic distribution system supports the 2 K primary, 4 K primary, and 35 - 55 K shield operation of more than 70 loads in the accelerator and the experimental areas. It is based on JLab and SNS experience with bayonet-type disconnects between the loads and the distribution system for phased commissioning and maintenance. The linac transfer line, which features three separate transfer line segments for additional independence during phased commissioning at 4 K and 2 K, connects the folded arrangement of 49 cryomodules and 4 superconducting dipole magnets and a fourth transfer line supports the separator area cryo loads. The pressure reliefs for the transfer line process lines, located in the refrigeration room outside the tunnel/accelerator area, are piped to be vented outdoors. The transfer line designs integrate supply and return flow paths into a combined vacuum space. The main linac distribution segments are produced in a small number of standard configurations; a prototype of one such configuration has been fabricated at Jefferson Lab and has been installed at MSU to support testing of a prototype FRIB cryomodule.

  12. A distributed clinical decision support system architecture

    Directory of Open Access Journals (Sweden)

    Shaker H. El-Sappagh


    Full Text Available This paper proposes an open and distributed clinical decision support system architecture. This technical architecture takes advantage of Electronic Health Record (EHR, data mining techniques, clinical databases, domain expert knowledge bases, available technologies and standards to provide decision-making support for healthcare professionals. The architecture will work extremely well in distributed EHR environments in which each hospital has its own local EHR, and it satisfies the compatibility, interoperability and scalability objectives of an EHR. The system will also have a set of distributed knowledge bases. Each knowledge base will be specialized in a specific domain (i.e., heart disease, and the model achieves cooperation, integration and interoperability between these knowledge bases. Moreover, the model ensures that all knowledge bases are up-to-date by connecting data mining engines to each local knowledge base. These data mining engines continuously mine EHR databases to extract the most recent knowledge, to standardize it and to add it to the knowledge bases. This framework is expected to improve the quality of healthcare, reducing medical errors and guaranteeing the safety of patients by helping clinicians to make correct, accurate, knowledgeable and timely decisions.

  13. Creation of cold nitric oxide by extraction of the cold fraction of a thermal distribution. (United States)

    Bichsel, Bryan J; Alexander, Jason; Dahal, Parshuram; Morrison, Michael A; Shafer-Ray, Neil E; Abraham, E R I


    We describe a device using the Stark effect to extract the cold fraction of nitric oxide molecules from a warmer thermal distribution. Room temperature NO is cryogenically cooled to 72-82 K and injected into a straight, hexapole guide that uses the Stark effect. By blocking line-of-sight trajectories from the input to the output, primarily the slowest molecules are guided around the obstruction and are transferred into a new chamber. We measure the temperature distribution using a field-stabilized Rydberg time-of-flight technique. A superposition of molecular Rydberg states is excited, sufficiently increasing the lifetime of the excited state for a time-of-flight measurement for cold molecular samples. We produce a continuous source of nitric oxide with temperatures ranging from 7 to 20 K in the lowest ro-vibrational state. The output temperature is controlled by the initial temperature distribution and the guide voltage.

  14. Thermal Simulation of a Contactor with Feedback Controlled Magnet System (United States)

    Ji, Liang; Chen, Degui; Liu, Yingyi; Li, Xingwen

    Similarities and differences of the thermal analysis issues between the intelligent and general AC contactors are analyzed. Heat source model of the magnet system is established according to the unique control mode of the intelligent AC contactor. Linking with the features common of the two kinds of contactors, the extension of the thermal analysis method of the general AC contactor to the intelligent AC contactor is demonstrated. Consequently, a comprehensive thermal analysis model considering heat sources of both main circuit and magnet system is constructed for the intelligent AC contactor. With this model, the steady-state temperature rise of the intelligent AC contactor is calculated and compared with the measurements of an actual intelligent AC contactor.

  15. Integrated thermal treatment systems study. Internal review panel report

    Energy Technology Data Exchange (ETDEWEB)

    Cudahy, J.; Escarda, T.; Gimpel, R. [and others


    The U.S. Department of Energy (DOE) Office of Technology Development (OTD) commissioned two studies to evaluate nineteen thermal treatment technologies for treatment of DOE mixed low-level waste. These studies were called the Integrated Thermal Treatment System (ITTS) Phase I and Phase II. With the help of the DOE Office of Environmental Management (EM) Mixed Waste Focus Group, OTD formed an ITTS Internal Review Panel to review and comment on the ITTS studies. This Panel was composed of scientists and engineers from throughout the DOE complex, the U.S. Environmental Protection Agency, the California EPA, and private experts. The Panel met from November 15-18, 1994 to review the ITTS studies and to make recommendations on the most promising thermal treatment systems for DOE mixed low-level wastes and on research and development necessary to prove the performance of the technologies. This report describes the findings and presents the recommendations of the Panel.

  16. Active Wireless Temperature Sensors for Aerospace Thermal Protection Systems (United States)

    Milos, Frank S.; Karunaratne, K.; Arnold, Jim (Technical Monitor)


    Health diagnostics is an area where major improvements have been identified for potential implementation into the design of new reusable launch vehicles in order to reduce life-cycle costs, to increase safety margins, and to improve mission reliability. NASA Ames is leading the effort to advance inspection and health management technologies for thermal protection systems. This paper summarizes a joint project between NASA Ames and Korteks to develop active wireless sensors that can be embedded in the thermal protection system to monitor sub-surface temperature histories. These devices are thermocouples integrated with radio-frequency identification circuitry to enable acquisition and non-contact communication of temperature data through aerospace thermal protection materials. Two generations of prototype sensors are discussed. The advanced prototype collects data from three type-k thermocouples attached to a 2.54-cm square integrated circuit.

  17. Thermally conductive cementitious grout for geothermal heat pump systems (United States)

    Allan, Marita


    A thermally conductive cement-sand grout for use with a geothermal heat pump system. The cement sand grout contains cement, silica sand, a superplasticizer, water and optionally bentonite. The present invention also includes a method of filling boreholes used for geothermal heat pump systems with the thermally conductive cement-sand grout. The cement-sand grout has improved thermal conductivity over neat cement and bentonite grouts, which allows shallower bore holes to be used to provide an equivalent heat transfer capacity. In addition, the cement-sand grouts of the present invention also provide improved bond strengths and decreased permeabilities. The cement-sand grouts can also contain blast furnace slag, fly ash, a thermoplastic air entraining agent, latex, a shrinkage reducing admixture, calcium oxide and combinations thereof.

  18. Projection of distributed-collector solar-thermal electric power plant economics to years 1990-2000 (United States)

    Fujita, T.; Elgabalawi, N.; Herrera, G.; Turner, R. H.


    A preliminary comparative evaluation of distributed-collector solar thermal power plants was undertaken by projecting power plant economics of selected systems to the 1990 to 2000 time frame. The selected systems include: (1) fixed orientation collectors with concentrating reflectors and vacuum tube absorbers, (2) one axis tracking linear concentrator including parabolic trough and variable slat designs, and (3) two axis tracking parabolic dish systems including concepts with small heat engine-electric generator assemblies at each focal point as well as approaches having steam generators at the focal point with pipeline collection to a central power conversion unit. Comparisons are presented primarily in terms of energy cost and capital cost over a wide range of operating load factors. Sensitvity of energy costs for a range of efficiency and cost of major subsystems/components is presented to delineate critical technological development needs.

  19. Conceptual design and analysis of a Dish-Rankine solar thermal power system (United States)

    Pons, R. L.


    A Point Focusing Distributed Receiver (PFDR) solar thermal electric system which employs small Organic Rankine Cycle (ORC) engines is examined with reference to its projected technical/economic performance. With mass-produced power modules (about 100,000 per year), the projected life-cycle energy cost for an optimized no-storage system is estimated at 67 mills/kWh (Levelized Busbar Energy Cost) without the need for advanced development of any of its components. At moderate production rates (about 50 MWe/yr) system energy costs are competitive with conventional power generation systems in special remote-site types of applications.

  20. Next Generation Multimedia Distributed Data Base Systems (United States)

    Pendleton, Stuart E.


    The paradigm of client/server computing is changing. The model of a server running a monolithic application and supporting clients at the desktop is giving way to a different model that blurs the line between client and server. We are on the verge of plunging into the next generation of computing technology--distributed object-oriented computing. This is not only a change in requirements but a change in opportunities, and requires a new way of thinking for Information System (IS) developers. The information system demands caused by global competition are requiring even more access to decision making tools. Simply, object-oriented technology has been developed to supersede the current design process of information systems which is not capable of handling next generation multimedia.

  1. LHCb: Monitoring the DIRAC Distribution System

    CERN Multimedia

    Nandakumar, R; Santinelli, R


    DIRAC is the LHCb gateway to any computing grid infrastructure (currently supporting WLCG) and is intended to reliably run large data mining activities. The DIRAC system consists of various services (which wait to be contacted to perform actions) and agents (which carry out periodic activities) to direct jobs as required. An important part of ensuring the reliability of the infrastructure is the monitoring and logging of these DIRAC distributed systems. The monitoring is done collecting information from two sources - one is from pinging the services or by keeping track of the regular heartbeats of the agents, and the other from the analysis of the error messages generated by both agents and services and collected by the logging system. This allows us to ensure that he components are running properly and to collect useful information regarding their operations. The process status monitoring is displayed using the SLS sensor mechanism which also automatically allows one to plot various quantities and also keep ...

  2. Building a generalized distributed system model (United States)

    Mukkamala, R.


    The key elements in the 1992-93 period of the project are the following: (1) extensive use of the simulator to implement and test - concurrency control algorithms, interactive user interface, and replica control algorithms; and (2) investigations into the applicability of data and process replication in real-time systems. In the 1993-94 period of the project, we intend to accomplish the following: (1) concentrate on efforts to investigate the effects of data and process replication on hard and soft real-time systems - especially we will concentrate on the impact of semantic-based consistency control schemes on a distributed real-time system in terms of improved reliability, improved availability, better resource utilization, and reduced missed task deadlines; and (2) use the prototype to verify the theoretically predicted performance of locking protocols, etc.

  3. Multilayer insulation thermal protection systems technology (United States)

    Hyde, E. H.


    A summary is presented of the work performed by Marshall Space Flight Center (MSFC) and industry toward the development of flight-type multilayer insulation(MLI) systems. The MSFC MLI program is divided into three large categories: (1) the generation and compilation of MLI composite test data; (2) the analysis, design, and testing of heat flow through MLI applied to ducting, seams, electrical feedthroughs, structural supports, and the tank sidewall; and (3) the development, modification, and utilization of new testing procedures, tanks, and the test facilities. Numerous data have been generated, analyzed, and documented on different MLI composites.

  4. Thermal Field Theory in Small Systems (United States)

    Horowitz, W. A.


    We compute the finite size corrections to the partition function in a Cartesian space of finite extent in M directions and of infinite extent in D - M directions for a massless, non-interacting scalar field theory. We then use this partition function to compute numerically the energy density, pressure, entropy density, and speed of sound for this theory for M = 1, 2, and 3 for D = 3 total spatial dimensions. The finite size corrections for the speed of sound are ˜ 600%, which indicates the need to consider these corrections in hydrodynamic simulations of small collision systems in high energy nuclear physics.

  5. Thermal Effects in Gravitational Hartree Systems

    KAUST Repository

    Aki, Gonca L.


    We consider the non-relativistic Hartree model in the gravitational case, i. e. with attractive Coulomb-Newton interaction. For a given mass M > 0, we construct stationary states with non-zero temperature T by minimizing the corresponding free energy functional. It is proved that minimizers exist if and only if the temperature of the system is below a certain threshold T* > 0 (possibly infinite), which itself depends on the specific choice of the entropy functional. We also investigate whether the corresponding minimizers are mixed or pure quantum states and characterize a critical temperature Tc ∈ (0,T*) above which mixed states appear. © 2011 Springer Basel AG.

  6. Thermal effects in gravitational Hartree systems

    Energy Technology Data Exchange (ETDEWEB)

    Aki, Gonca L. [Weierstrass-Institut fuer Angewandte Analysis und Stochastik (WIAS) im Forschungsverbund Berlin e.V. (Germany); Dolbeault, Jean [Paris-Dauphine Univ. (FR). Ceremade (UMR CNRS 7534); Sparber, Christof [Illinois Univ., Chicago, IL (United States). Dept. of Mathematics, Statistics, and Computer Science


    We consider the non-relativistic Hartree model in the gravitational case, i.e. with attractive Coulomb-Newton interaction. For a given mass M>0, we construct stationary states with non-zero temperature T by minimizing the corresponding free energy functional. It is proved that minimizers exist if and only if the temperature of the system is below a certain threshold T*>0 (possibly infinite), which itself depends on the specific choice of the entropy functional. We also investigate whether the corresponding minimizers are mixed or pure quantum states and characterize a critical temperature T{sub c} element of (0,T*) above which mixed states appear. (orig.)

  7. The Rapidity Distributions and the Thermalization Induced Transverse Momentum Distributions in Au-Au Collisions at RHIC Energies

    Directory of Open Access Journals (Sweden)

    Zhi-Jin Jiang


    Full Text Available It is widely believed that the quark-gluon plasma (QGP might be formed in the current heavy ion collisions. It is also widely recognized that the relativistic hydrodynamics is one of the best tools for describing the process of expansion and hadronization of QGP. In this paper, by taking into account the effects of thermalization, a hydrodynamic model including phase transition from QGP state to hadronic state is used to analyze the rapidity and transverse momentum distributions of identified charged particles produced in heavy ion collisions. A comparison is made between the theoretical results and experimental data. The theoretical model gives a good description of the corresponding measurements made in Au-Au collisions at RHIC energies.

  8. Thermal Infrared Remote Sensing of the Yellowstone Geothermal System (United States)

    Vaughan, R. G.; Keszthelyi, L. P.; Heasler, H.; Jaworowski, C.; Lowenstern, J. B.; Schneider, D. J.


    The Yellowstone National Park (YNP) geothermal system is one of the largest in the world, with thousands of individual thermal features ranging in size from a few centimeters to tens of meters across, (e.g., fumaroles, geysers, mud pots and hot spring pools). Together, large concentrations of these thermal features make up dozens of distinct thermal areas, characterized by sparse vegetation, hydrothermally altered rocks, and usually either sinter, travertine, or acid sulfate alteration. The temperature of these thermal features generally ranges from ~30 to ~93 oC, which is the boiling temperature of water at the elevation of Yellowstone. In-situ temperature measurements of various thermal features are sparse in both space and time, but they show a dynamic time-temperature relationship. For example, as geysers erupt and send pulses of warm water down slope, the warm water cools rapidly and is then followed by another pulse of warm water, on time scales of minutes. The total heat flux from the Park’s thermal features has been indirectly estimated from chemical analysis of Cl- flux in water flowing from Yellowstone’s rivers. We are working to provide a more direct measurement, as well as estimates of time variability, of the total heat flux using satellite multispectral thermal infrared (TIR) remote sensing data. Over the last 10 years, NASA’s orbiting ASTER and MODIS instruments have acquired hundreds and thousands of multispectral TIR images, respectively, over the YNP area. Compared with some volcanoes, Yellowstone is a relatively low-temperature geothermal system, with low thermal contrast to the non-geothermal surrounding areas; therefore we are refining existing techniques to extract surface temperature and thermal flux information. This task is complicated by issues such as, during the day, solar heated surfaces may be warmer than nearby geothermal features; and there is some topographic (elevation) influence on surface temperatures, even at night. Still

  9. Review of the integrated thermal and nonthermal treatment system studies

    Energy Technology Data Exchange (ETDEWEB)



    This report contains a review and evaluation of three systems analysis studies performed by LITCO on integrated thermal treatment systems and integrated nonthermal treatment systems for the remediation of mixed low-level waste stored throughout the US Department of Energy weapons complex. The review was performed by an independent team of nine researchers from the Energy and Environmental Research Center, Science Applications International Corporation, the Waste Policy Institute, and Virginia Tech. The purpose of this review was to (1) determine whether the assumptions of the studies were adequate to produce an unbiased review of both thermal and nonthermal systems, (2) to identify the critical areas of the studies that would benefit from further investigation, and (3) to develop a standard template that could be used in future studies to assure a sound application of systems engineering.

  10. A Rewriting-Logic-Based Technique for Modeling Thermal Systems

    Directory of Open Access Journals (Sweden)

    Daniela Lepri


    Full Text Available This paper presents a rewriting-logic-based modeling and analysis technique for physical systems, with focus on thermal systems. The contributions of this paper can be summarized as follows: (i providing a framework for modeling and executing physical systems, where both the physical components and their physical interactions are treated as first-class citizens; (ii showing how heat transfer problems in thermal systems can be modeled in Real-Time Maude; (iii giving the implementation in Real-Time Maude of a basic numerical technique for executing continuous behaviors in object-oriented hybrid systems; and (iv illustrating these techniques with a set of incremental case studies using realistic physical parameters, with examples of simulation and model checking analyses.

  11. Distributed Online Learning in Social Recommender Systems (United States)

    Tekin, Cem; Zhang, Simpson; van der Schaar, Mihaela


    In this paper, we consider decentralized sequential decision making in distributed online recommender systems, where items are recommended to users based on their search query as well as their specific background including history of bought items, gender and age, all of which comprise the context information of the user. In contrast to centralized recommender systems, in which there is a single centralized seller who has access to the complete inventory of items as well as the complete record of sales and user information, in decentralized recommender systems each seller/learner only has access to the inventory of items and user information for its own products and not the products and user information of other sellers, but can get commission if it sells an item of another seller. Therefore the sellers must distributedly find out for an incoming user which items to recommend (from the set of own items or items of another seller), in order to maximize the revenue from own sales and commissions. We formulate this problem as a cooperative contextual bandit problem, analytically bound the performance of the sellers compared to the best recommendation strategy given the complete realization of user arrivals and the inventory of items, as well as the context-dependent purchase probabilities of each item, and verify our results via numerical examples on a distributed data set adapted based on Amazon data. We evaluate the dependence of the performance of a seller on the inventory of items the seller has, the number of connections it has with the other sellers, and the commissions which the seller gets by selling items of other sellers to its users.

  12. Distributed design approach in persistent identifiers systems (United States)

    Golodoniuc, Pavel; Car, Nicholas; Klump, Jens


    The need to identify both digital and physical objects is ubiquitous in our society. Past and present persistent identifier (PID) systems, of which there is a great variety in terms of technical and social implementations, have evolved with the advent of the Internet, which has allowed for globally unique and globally resolvable identifiers. PID systems have catered for identifier uniqueness, integrity, persistence, and trustworthiness, regardless of the identifier's application domain, the scope of which has expanded significantly in the past two decades. Since many PID systems have been largely conceived and developed by small communities, or even a single organisation, they have faced challenges in gaining widespread adoption and, most importantly, the ability to survive change of technology. This has left a legacy of identifiers that still exist and are being used but which have lost their resolution service. We believe that one of the causes of once successful PID systems fading is their reliance on a centralised technical infrastructure or a governing authority. Golodoniuc et al. (2016) proposed an approach to the development of PID systems that combines the use of (a) the Handle system, as a distributed system for the registration and first-degree resolution of persistent identifiers, and (b) the PID Service (Golodoniuc et al., 2015), to enable fine-grained resolution to different information object representations. The proposed approach solved the problem of guaranteed first-degree resolution of identifiers, but left fine-grained resolution and information delivery under the control of a single authoritative source, posing risk to the long-term availability of information resources. Herein, we develop these approaches further and explore the potential of large-scale decentralisation at all levels: (i) persistent identifiers and information resources registration; (ii) identifier resolution; and (iii) data delivery. To achieve large-scale decentralisation

  13. Active Coordinated Operation of Distribution Network System for Many Connections of Distributed Generators (United States)

    Hayashi, Yasuhiro; Kawasaki, Shoji; Matsuki, Junya; Wakao, Shinji; Baba, Junpei; Hojo, Masahide; Yokoyama, Akihiko; Kobayashi, Naoki; Hirai, Takao; Oishi, Kohei

    Recently, total number of distributed generators (DGS) such as photovoltaic generation system and wind turbine generation system connected to an actual distribution network increases drastically. The distribution network connected with many distributed generators must be operated keeping reliability of power supply, power quality and loss minimization. In order to accomplish active distribution network operation to take advantage of many connections of DGS, a new coordinated operation of distribution system with many connections of DGS is necessary. In this paper, the authors propose a coordinated operation of distribution network system connected with many DGS by using newly proposed sectionalizing switches control, sending voltage control and computation of available DG connection capability. In order to check validity of the proposed coordinated operation of distribution system, numerical simulations using the proposed coordinated distribution system operation are carried out in a practical distribution network model.

  14. Storage and distribution system for multimedia information (United States)

    Murakami, Tokumichi


    Recent advances in technologies such as digital signal processing, LSI devices and storage media have led to an explosive growth in multimedia environment. Multimedia information services are expected to provide an information-oriented infrastructure which will integrate visual communication, broadcasting and computer services. International standardizations in video/audio coding accelerate permeation of these services into society. In this paper, from trends of R & D and international standardization in video coding techniques, an outline is given of a storage and distribution system for multimedia information, and a summary of the requirements of digital storage media.

  15. The Design Methodology of Distributed Computer Systems. (United States)


    TRANSMITTAL TO DDC This technical report has been reviewed and is approved for public release lAW AR 190-12 (7b). Distribution is unlimited. A. D. BLOSE...Evaluation of Asynchronous Concurrent System 3.1 Review of Petri Nets 3.1.1 Basic Properties of Petri Nets Petri nets (PET 77, AGE 75) are a formal...the 2nd International Conference on Software Engineering, October, 1976. ([IZ 72) Brinch Hanse , P., "Structure Multiprogramming," Comm. ACM, Vol, 15

  16. European standards for thermal solar systems and components. The finals

    NARCIS (Netherlands)

    Drück, H.; Heidemann, W.; Müller, H.; Veenstra, A.


    In Europe standards for solar collectors, hot water stores and for complete thermal solar systems have been developed during the past six years. This year (2001) these European Standards were established and therefore replaced all corresponding national standards. In the new European standards basic

  17. thermal power stations' reliability evaluation in a hydrothermal system

    African Journals Online (AJOL)

    Dr Obe

    A quantitative tool for the evaluation of thermal power stations reliability in a hydrothermal system is presented. A reliable power station is one which would supply the required power within its installed capacity at any time within the specified voltage and frequency limits. Required for this evaluation are the station's installed ...

  18. Effective thermal conductivity of real two-phase systems using ...

    Indian Academy of Sciences (India)


    non-uniform shape of the particles and non-linear flow of heat flux lines in real systems, incorporating an empirical correction factor in place of physical porosity modifies an expression for ETC. An effort is made to correlate it in terms of the ratio of thermal conductivities of the constituents and the physical porosity. Theo-.

  19. Study of thermally coupled distillation systems for energy-efficient ...

    Indian Academy of Sciences (India)

    Study of thermally coupled distillation systems for energy-efficient distillation. NEHA SAXENA1, NILESH MALI2,* and SATCHIDANAND SATPUTE3. 1 Department of Chemical Engineering, Bharati Vidyapeeth Deemed University College of Engineering,. Pune 411046, India. 2 Chemical Engineering and Process ...

  20. Data management system for distributed virtual screening. (United States)

    Zhou, Ting; Caflisch, Amedeo


    High throughput docking (HTD) using high performance computing platforms is a multidisciplinary challenge. To handle HTD data effectively and efficiently, we have developed a distributed virtual screening data management system (DVSDMS) in which the data handling and the distribution of jobs are realized by the open-source structured query language database software MySQL. The essential concept of DVSDMS is the separation of the data management from the docking and ranking applications. DVSDMS can be used to dock millions of molecules effectively, monitor the process in real time, analyze docking results promptly, and process up to 10(8) poses by energy ranking techniques. In an HTD campaign to identify kinase inhibitors a low cost Linux PC has allowed DVSDMS to efficiently assign the workload to more than 500 computing clients. Notably, in a stress test of DVSDMS that emulated a large number of clients, about 60 molecules per second were distributed to the clients for docking, which indicates that DVSDMS can run efficiently on very large compute cluster (up to about 40000 cores).

  1. Analysis and control of distributed cooperative systems.

    Energy Technology Data Exchange (ETDEWEB)

    Feddema, John Todd; Parker, Eric Paul; Wagner, John S.; Schoenwald, David Alan


    As part of DARPA Information Processing Technology Office (IPTO) Software for Distributed Robotics (SDR) Program, Sandia National Laboratories has developed analysis and control software for coordinating tens to thousands of autonomous cooperative robotic agents (primarily unmanned ground vehicles) performing military operations such as reconnaissance, surveillance and target acquisition; countermine and explosive ordnance disposal; force protection and physical security; and logistics support. Due to the nature of these applications, the control techniques must be distributed, and they must not rely on high bandwidth communication between agents. At the same time, a single soldier must easily direct these large-scale systems. Finally, the control techniques must be provably convergent so as not to cause undo harm to civilians. In this project, provably convergent, moderate communication bandwidth, distributed control algorithms have been developed that can be regulated by a single soldier. We have simulated in great detail the control of low numbers of vehicles (up to 20) navigating throughout a building, and we have simulated in lesser detail the control of larger numbers of vehicles (up to 1000) trying to locate several targets in a large outdoor facility. Finally, we have experimentally validated the resulting control algorithms on smaller numbers of autonomous vehicles.

  2. Physical Effects of Distributed PV Generation on California's Distribution System

    CERN Document Server

    Cohen, Michael A


    Deployment of high-penetration photovoltaic (PV) power is expected to have a range of effects -- both positive and negative -- on the distribution grid. The magnitude of these effects may vary greatly depending upon feeder topology, climate, PV penetration level, and other factors. In this paper we present a simulation study of eight representative distribution feeders in three California climates at PV penetration levels up to 100\\%, supported by a unique database of distributed PV generation data that enables us to capture the impact of PV variability on feeder voltage and voltage regulating equipment. When comparing the influence of feeder location (i.e. climate) versus feeder type on outcomes, we find that location more strongly influences the incidence of reverse power flow, reductions in peak loading and the presence of voltage excursions. On the other hand, we find that feeder characteristics more strongly influence the magnitude of loss reduction and changes in voltage regulator operations. We find th...

  3. Lighting system with thermal management system having point contact synthetic jets (United States)

    Arik, Mehmet; Weaver, Stanton Earl; Kuenzler, Glenn Howard; Wolfe, Jr., Charles Franklin; Sharma, Rajdeep


    Lighting system having unique configurations are provided. For instance, the lighting system may include a light source, a thermal management system and driver electronics, each contained within a housing structure. The light source is configured to provide illumination visible through an opening in the housing structure. The thermal management system includes a plurality of synthetic jets. The synthetic jets are arranged within the lighting system such that they are secured at contact points.

  4. Distribution of copper, silver and gold during thermal treatment with brominated flame retardants

    Energy Technology Data Exchange (ETDEWEB)

    Oleszek, Sylwia, E-mail: [Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, 1,1 Katahira, 2-Chome, Sendai 980-8577 (Japan); Institute of Environmental Engineering of the Polish Academy of Sciences, 34 M. Sklodowska-Curie St., 41-819 Zabrze (Poland); Grabda, Mariusz, E-mail: [Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, 1,1 Katahira, 2-Chome, Sendai 980-8577 (Japan); Institute of Environmental Engineering of the Polish Academy of Sciences, 34 M. Sklodowska-Curie St., 41-819 Zabrze (Poland); Shibata, Etsuro, E-mail: [Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, 1,1 Katahira, 2-Chome, Sendai 980-8577 (Japan); Nakamura, Takashi, E-mail: [Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, 1,1 Katahira, 2-Chome, Sendai 980-8577 (Japan)


    Highlights: • Copper, silver and gold during thermal treatment with brominated flame retardants. • Distribution of copper, silver and gold during thermal processing. • Thermodynamic considerations of the bromination reactions. - Abstract: The growing consumption of electric and electronic equipment results in creating an increasing amount of electronic waste. The most economically and environmentally advantageous methods for the treatment and recycling of waste electric and electronic equipment (WEEE) are the thermal techniques such as direct combustion, co-combustion with plastic wastes, pyrolysis and gasification. Nowadays, this kind of waste is mainly thermally treated in incinerators (e.g. rotary kilns) to decompose the plastics present, and to concentrate metals in bottom ash. The concentrated metals (e.g. copper, precious metals) can be supplied as a secondary raw material to metal smelters, while the pyrolysis of plastics allows the recovery of fuel gases, volatilising agents and, eventually, energy. Indeed, WEEE, such as a printed circuit boards (PCBs) usually contains brominated flame retardants (BFRs). From these materials, hydrobromic acid (HBr) is formed as a product of their thermal decomposition. In the present work, the bromination was studied of copper, silver and gold by HBr, originating from BFRs, such as Tetrabromobisphenol A (TBBPA) and Tetrabromobisphenol A-Tetrabromobisophenol A diglycidyl ether (TTDE) polymer; possible volatilization of the bromides formed was monitored using a thermo-gravimetric analyzer (TGA) and a laboratory-scale furnace for treating samples of metals and BFRs under an inert atmosphere and at a wide range of temperatures. The results obtained indicate that up to about 50% of copper and silver can evolve from sample residues in the form of volatile CuBr and AgBr above 600 and 1000 °C, respectively. The reactions occur in the molten resin phase simultaneously with the decomposition of the brominated resin. Gold is

  5. Load Frequency Control of AC Microgrid Interconnected Thermal Power System (United States)

    Lal, Deepak Kumar; Barisal, Ajit Kumar


    In this paper, a microgrid (MG) power generation system is interconnected with a single area reheat thermal power system for load frequency control study. A new meta-heuristic optimization algorithm i.e. Moth-Flame Optimization (MFO) algorithm is applied to evaluate optimal gains of the fuzzy based proportional, integral and derivative (PID) controllers. The system dynamic performance is studied by comparing the results with MFO optimized classical PI/PID controllers. Also the system performance is investigated with fuzzy PID controller optimized by recently developed grey wolf optimizer (GWO) algorithm, which has proven its superiority over other previously developed algorithm in many interconnected power systems.

  6. Thermal-Induced Refractive Index Change Effects on Distributed Modal Filtering Properties of Rod-Type Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Coscelli, E.; Poli, Federica; Jørgensen, Mette Marie


    The effects of thermally-induced refractive index change on distributed modal filtering rod-type photonic crystal fibers are numerically investigated. Results have shown a significant blue-shift of the single-mode range for increasing temperature.......The effects of thermally-induced refractive index change on distributed modal filtering rod-type photonic crystal fibers are numerically investigated. Results have shown a significant blue-shift of the single-mode range for increasing temperature....

  7. Predictive analysis of thermal distribution and damage in thermotherapy on biological tissue (United States)

    Fanjul-Vélez, Félix; Arce-Diego, José Luis


    The use of optical techniques is increasing the possibilities and success of medical praxis in certain cases, either in tissue characterization or treatment. Photodynamic therapy (PDT) or low intensity laser treatment (LILT) are two examples of the latter. Another very interesting implementation is thermotherapy, which consists of controlling temperature increase in a pathological biological tissue. With this method it is possible to provoke an improvement on specific diseases, but a previous analysis of treatment is needed in order for the patient not to suffer any collateral damage, an essential point due to security margins in medical procedures. In this work, a predictive analysis of thermal distribution in a biological tissue irradiated by an optical source is presented. Optical propagation is based on a RTT (Radiation Transport Theory) model solved via a numerical Monte Carlo method, in a multi-layered tissue. Data obtained are included in a bio-heat equation that models heat transference, taking into account conduction, convection, radiation, blood perfusion and vaporization depending on the specific problem. Spatial-temporal differential bio-heat equation is solved via a numerical finite difference approach. Experimental temperature distributions on animal tissue irradiated by laser radiation are shown. From thermal distribution in tissue, thermal damage is studied, based on an Arrhenius analysis, as a way of predicting harmful effects. The complete model can be used for concrete treatment proposals, as a way of predicting treatment effects and consequently decide which optical source parameters are appropriate for the specific disease, mainly wavelength and optical power, with reasonable security margins in the process.

  8. Magnetization Plateaus and Thermal Entanglement of Spin Systems (United States)

    Ananikian, N.; Burdík, Č.; Ananikyan, L.; Poghosyan, H.


    The geometrically magnetic frustrations and quantum thermal entanglement of antiferromagnetic metal-containing compounds are considered on a diamond chain. We researched the magnetic and thermal properties of the symmetric Hubbard dimers with delocalized interstitial spins and the quantum entanglement states. It is presented magnetization plateaus and negativity in spin-1 Ising-Heisenberg model using transfer matrix technique. Applying the dynamic system approach we study the magnetic curves, Lyapunov exponents and superstable point in the two-dimensional mapping for the partition function of spin-1 classical and Ising-Heisenberg models at T → 0 on a diamond chain.

  9. Distributed Power-Generation Systems and Protection

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Yang, Yongheng; Yang, Dongsheng


    Continuously expanding deployments of distrib¬uted power-generation systems (DPGSs) are transforming the conventional centralized power grid into a mixed distributed electrical network. The modern power grid requires flexible energy utilization but presents challenges in the case of a high...... penetration degree of renewable energy, among which wind and solar photovoltaics are typical sources. The integration level of the DPGS into the grid plays a critical role in developing sustainable and resilient power systems, especially with highly intermittent renewable energy resources. To address...... the challenging issues and, more importantly, to leverage the energy generation, stringent demands from both utility operators and consumers have been imposed on the DPGS. Furthermore, as the core of energy conversion, numerous power electronic converters employing advanced control techniques have been developed...

  10. Distribution in flowing reaction-diffusion systems

    KAUST Repository

    Kamimura, Atsushi


    A power-law distribution is found in the density profile of reacting systems A+B→C+D and 2A→2C under a flow in two and three dimensions. Different densities of reactants A and B are fixed at both ends. For the reaction A+B, the concentration of reactants asymptotically decay in space as x-1/2 and x-3/4 in two dimensions and three dimensions, respectively. For 2A, it decays as log (x) /x in two dimensions. The decay of A+B is explained considering the effect of segregation of reactants in the isotropic case. The decay for 2A is explained by the marginal behavior of two-dimensional diffusion. A logarithmic divergence of the diffusion constant with system size is found in two dimensions. © 2009 The American Physical Society.

  11. Control and Operation of Islanded Distribution System

    DEFF Research Database (Denmark)

    Mahat, Pukar

    with more than one generator connected to the same system. An isochronous controller with feedback has been developed in this research study. It performs relatively well in both islanded and grid connected conditions. Hence, if there is more than one DG unit in the distribution system, employing isochronous...... of power supply provided that various issues with islanding are properly addressed. Some of the issues with islanding are state (islanded or grid connected) detection, control of voltage and frequency, load control and protection. In this dissertation, some of the major technical issues with islanding...... power shift). However, the active technique is used only when the passive technique cannot clearly discriminate between islanded and grid connected conditions. DG units perform the best if they are operated with droop control and power factor control when they are operating parallel to the grid...

  12. Global resilience analysis of water distribution systems. (United States)

    Diao, Kegong; Sweetapple, Chris; Farmani, Raziyeh; Fu, Guangtao; Ward, Sarah; Butler, David


    Evaluating and enhancing resilience in water infrastructure is a crucial step towards more sustainable urban water management. As a prerequisite to enhancing resilience, a detailed understanding is required of the inherent resilience of the underlying system. Differing from traditional risk analysis, here we propose a global resilience analysis (GRA) approach that shifts the objective from analysing multiple and unknown threats to analysing the more identifiable and measurable system responses to extreme conditions, i.e. potential failure modes. GRA aims to evaluate a system's resilience to a possible failure mode regardless of the causal threat(s) (known or unknown, external or internal). The method is applied to test the resilience of four water distribution systems (WDSs) with various features to three typical failure modes (pipe failure, excess demand, and substance intrusion). The study reveals GRA provides an overview of a water system's resilience to various failure modes. For each failure mode, it identifies the range of corresponding failure impacts and reveals extreme scenarios (e.g. the complete loss of water supply with only 5% pipe failure, or still meeting 80% of demand despite over 70% of pipes failing). GRA also reveals that increased resilience to one failure mode may decrease resilience to another and increasing system capacity may delay the system's recovery in some situations. It is also shown that selecting an appropriate level of detail for hydraulic models is of great importance in resilience analysis. The method can be used as a comprehensive diagnostic framework to evaluate a range of interventions for improving system resilience in future studies. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  13. A Simple Adaptive Overcurrent Protection of Distribution Systems With Distributed Generation

    DEFF Research Database (Denmark)

    Mahat, Pukar; Chen, Zhe; Bak-Jensen, Birgitte


    current when the system is connected to the grid and when it is islanded. This paper proposes the use of adaptive protection, using local information, to overcome the challenges of the overcurrent protection in distribution systems with distributed generation. The trip characteristics of the relays......A significant increase in the penetration of distributed generation has resulted in a possibility of operating distribution systems with distributed generation in islanded mode. However, over-current protection of an islanded distribution system is still an issue due to the difference in fault...... and the protection system settings can be updated to clear the fault quicker....

  14. Thermal degradation features of peppermint oil in a binary system with Β- cyclodextrin

    Directory of Open Access Journals (Sweden)

    I. A. Omelchenko


    Full Text Available Aim. One of the most promising ways of changing physical and chemical properties of the active pharmaceutical ingredient is an encapsulation on a molecular level with the use of cyclodextrins. This makes it possible to create products with the desired activity and controlled distribution in the body. Methods and results. We have studied the thermal decomposition of peppermint oil in binary systems with β-cyclodextrin. It has been found that the thermal degradation of mechanical mixture and inclusion complex of the «host-guest» with the composition of 1:1 passes through different mechanisms. Conclusions. It is shown that the given data of thermal stability are useful for the identification of an inclusion complex «β-CD – peppermint oil» and assessing its complexation, and for the development of technology of medicinal forms of supramolecular complex of β-cyclodextrin and peppermint oil

  15. A Remote Tracing Facility For Distributed Systems

    CERN Document Server

    Ehm, F


    Today, CERN's control system is built upon a large number of C++ and Java services producing log events. In such a largely distributed environment these log messages are essential for problem recognition and tracing. Tracing is therefore vital for operation as understanding an issue in a subsystem means analysing log events in an efficient and fast manner. At present 3150 device servers are deployed on 1600 diskless frontends and they send their log messages via the network to an in-house developed central server which, in turn, saves them to files. However, this solution is not able to provide several highly desired features and has performance limitations which led to the development of a new solution. The new distributed tracing facility fulfils these requirements by taking advantage of the Streaming Text Oriented Messaging Protocol (STOMP) and ActiveMQ as the transport layer. The system not only allows storing critical log events centrally in files or in a database but also allows other clients (e.g. grap...

  16. Hot Thermal Storage in a Variable Power, Renewable Energy System (United States)


    commercially proven and available energy collection, conversion , and storage systems and equipment. Chapter IV presents a method for innovative integration of...molten salt. On a grid scale, off-peak electricity, converted by ohmic heating, and thermal energy from a concentrated solar power ( CSP ) plant...renewable generation system with heat storage. It reviews the available energy sources as well as methods for energy conversion and storage. A

  17. Thermal Analysis of a Solar Powered Absorption Cooling System with Fully Mixed Thermal Storage at Startup

    Directory of Open Access Journals (Sweden)

    Camelia Stanciu


    Full Text Available A simple effect one stage ammonia-water absorption cooling system fueled by solar energy is analyzed. The considered system is composed by a parabolic trough collector concentrating solar energy into a tubular receiver for heating water. This is stored in a fully mixed thermal storage tank and used in the vapor generator of the absorption cooling system. Time dependent cooling load is considered for the air conditioning of a residential two-storey house. A parametric study is performed to analyze the operation stability of the cooling system with respect to solar collector and storage tank dimensions. The results emphasized that there is a specific storage tank dimension associated to a specific solar collector dimension that could ensure the longest continuous startup operation of the cooling system when constant mass flow rates inside the system are assumed.

  18. Engineering Aerothermal Analysis for X-34 Thermal Protection System Design (United States)

    Wurster, Kathryn E.; Riley, Christopher J.; Zoby, E. Vincent


    Design of the thermal protection system for any hypersonic flight vehicle requires determination of both the peak temperatures over the surface and the heating-rate history along the flight profile. In this paper, the process used to generate the aerothermal environments required for the X-34 Testbed Technology Demonstrator thermal protection system design is described as it has evolved from a relatively simplistic approach based on engineering methods applied to critical areas to one of detailed analyses over the entire vehicle. A brief description of the trajectory development leading to the selection of the thermal protection system design trajectory is included. Comparisons of engineering heating predictions with wind-tunnel test data and with results obtained using a Navier-Stokes flowfield code and an inviscid/boundary layer method are shown. Good agreement is demonstrated among all these methods for both the ground-test condition and the peak heating flight condition. Finally, the detailed analysis using engineering methods to interpolate the surface-heating-rate results from the inviscid/boundary layer method to predict the required thermal environments is described and results presented.

  19. CTS TEP thermal anomalies: Heat pipe system performance (United States)

    Marcus, B. D.


    A part of the investigation is summarized of the thermal anomalies of the transmitter experiment package (TEP) on the Communications Technology Satellite (CTS) which were observed on four occasions in 1977. Specifically, the possible failure modes of the variable conductance heat pipe system (VCHPS) used for principal thermal control of the high-power traveling wave tube in the TEP are considered. Further, the investigation examines how those malfunctions may have given rise to the TEP thermal anomalies. Using CTS flight data information, ground test results, analysis conclusions, and other relevant information, the investigation concentrated on artery depriming as the most likely VCHPS failure mode. Included in the study as possible depriming mechanisms were freezing of the working fluid, Marangoni flow, and gas evolution within the arteries. The report concludes that while depriming of the heat pipe arteries is consistent with the bulk of the observed data, the factors which cause the arteries to deprime have yet to be identified.

  20. Computational design and experimental validation of new thermal barrier systems

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Shengmin [Louisiana State Univ., Baton Rouge, LA (United States)


    The focus of this project is on the development of a reliable and efficient ab initio based computational high temperature material design method which can be used to assist the Thermal Barrier Coating (TBC) bond-coat and top-coat design. Experimental evaluations on the new TBCs are conducted to confirm the new TBCs’ properties. Southern University is the subcontractor on this project with a focus on the computational simulation method development. We have performed ab initio density functional theory (DFT) method and molecular dynamics simulation on screening the top coats and bond coats for gas turbine thermal barrier coating design and validation applications. For experimental validations, our focus is on the hot corrosion performance of different TBC systems. For example, for one of the top coatings studied, we examined the thermal stability of TaZr2.75O8 and confirmed it’s hot corrosion performance.

  1. Isothiocyanate metabolism, distribution, and interconversion in mice following consumption of thermally processed broccoli sprouts or purified sulforaphane. (United States)

    Bricker, Gregory V; Riedl, Kenneth M; Ralston, Robin A; Tober, Kathleen L; Oberyszyn, Tatiana M; Schwartz, Steven J


    Broccoli sprouts are a rich source of glucosinolates, a group of phytochemicals that when hydrolyzed, are associated with cancer prevention. Our objectives were to investigate the metabolism, distribution, and interconversion of isothiocyanates (ITCs) in mice fed thermally processed broccoli sprout powders (BSPs) or the purified ITC sulforaphane. For 1 wk, mice were fed a control diet (n = 20) or one of four treatment diets (n = 10 each) containing nonheated BSP, 60°C mildly heated BSP, 5-min steamed BSP, or 3 mmol purified sulforaphane. Sulforaphane and erucin metabolite concentrations in skin, liver, kidney, bladder, lung, and plasma were quantified using HPLC-MS/MS. Thermal intensity of BSP processing had disparate effects on ITC metabolite concentrations upon consumption. Mild heating generally resulted in the greatest ITC metabolite concentrations in vivo, followed by the nonheated and steamed BSP diets. We observed interconversion between sulforaphane and erucin species or metabolites, and report that erucin is the favored form in liver, kidney, and bladder, even when only sulforaphane is consumed. ITC metabolites were distributed to all tissues analyzed, suggesting the potential for systemic benefits. We report for the first time tissue-dependent ratio of sulforaphane and erucin, though further investigation is warranted to assess biological activity of individual forms. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Systems Analysis for Thermal Infrared ` THz Torch' Applications (United States)

    Hu, Fangjing; Sun, Jingye; Brindley, Helen E.; Liang, Xiaoxin; Lucyszyn, Stepan


    The ` THz Torch' concept was recently introduced by the authors for providing secure wireless communications over short distances within the thermal infrared (10-100 THz). Unlike conventional systems, thermal infrared can exploit front-end thermodynamics with engineered blackbody radiation. For the first time, a detailed power link budget analysis is given for this new form of wireless link. The mathematical modeling of a short end-to-end link is provided, which integrates thermodynamics into conventional signal and noise power analysis. As expected from the Friis formula for noise, it is found that the noise contribution from the pyroelectric detector dominates intrinsic noise. From output signal and noise voltage measurements, experimental values for signal-to-noise ratio (SNR) are obtained and compared with calculated predictions. As with conventional communications systems, it is shown for the first time that the measured SNR and measured bit error rate found with this thermodynamics-based system resembles classical empirical models. Our system analysis can serve as an invaluable tool for the development of thermal infrared systems, accurately characterizing each individual channel and, thus, enables the performance of multi-channel ` THz Torch' systems to be optimized.

  3. Stability analysis of distributed order fractional chen system. (United States)

    Aminikhah, H; Refahi Sheikhani, A; Rezazadeh, H


    We first investigate sufficient and necessary conditions of stability of nonlinear distributed order fractional system and then we generalize the integer-order Chen system into the distributed order fractional domain. Based on the asymptotic stability theory of nonlinear distributed order fractional systems, the stability of distributed order fractional Chen system is discussed. In addition, we have found that chaos exists in the double fractional order Chen system. Numerical solutions are used to verify the analytical results.

  4. Various startup system designs of HPLWR and their thermal analysis

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Qi [School of Physics and Engineering, Sun Yat-sen University, Guangzhou (China); Cai, Jiejin, E-mail: [School of Physics and Engineering, Sun Yat-sen University, Guangzhou (China); Sino-French Institute of Nuclear Engineering and Technology, Sun Yat-sen University, Guangzhou (China)


    Highlights: • An axial one-dimensional (1D) single channel model is developed for the HPLWR core. • Various startup systems for HPLWR have been investigated and found feasible. • Characteristics of the component required for HPLWR startup designs are studied. -- Abstract: This paper summarizes the results of various startup system designs and their thermal analysis of the high performance light water reactor (HPLWR) which is the European version of the various supercritical water cooled reactor proposals. In order to study the thermal-hydraulic characteristics of the HPLWR core, a simplified axial one-dimensional (1D) single channel model is developed, which consists of fuel, cladding, coolant and moderator. The model is verified by the related results of Seppälä (2008). Both constant pressure startup systems and sliding pressure startup systems of HPLWR are presented. In constant pressure startup system, the reactor starts at supercritical pressure. It appears that compared with other SCWR designs, the weight of the component required for constant pressure startup of HPLWR is medium and reasonable. Constant pressure startup systems are found feasible from thermal analysis. And for sliding pressure startup, the reactor starts at subcritical pressure. The adequate core power of 25% with 28% flow rate and a feedwater temperature of 280 °C are determined during pressurization phase. The thermal analysis results show that the sliding pressure startup systems for HPLWR are also feasible. Considering the same flow rate as the supercritical-pressure light water-cooled fast reactor (SCFR), the component weight required is reduced in HPLWR.

  5. MDSplus automated build and distribution system

    Energy Technology Data Exchange (ETDEWEB)

    Fredian, T., E-mail: [Massachusetts Institute of Technology, 175 Albany Street, Cambridge, MA 02139 (United States); Stillerman, J. [Massachusetts Institute of Technology, 175 Albany Street, Cambridge, MA 02139 (United States); Manduchi, G. [Consorzio RFX, Euratom-ENEA Association, Corso Stati Uniti 4, Padova 35127 (Italy)


    Support of the MDSplus data handling system has been enhanced by the addition of an automated build system which does nightly builds of MDSplus for many computer platforms producing software packages which can now be downloaded using a web browser or via package repositories suitable for automatic updating. The build system was implemented using an extensible continuous integration server product called Hudson which schedules software builds on a collection of VMware based virtual machines. New releases are created based on updates via the MDSplus cvs code repository and versioning are managed using cvs tags and branches. Currently stable, beta and alpha releases of MDSplus are maintained for eleven different platforms including Windows, MacOSX, RedHat Enterprise Linux, Fedora, Ubuntu and Solaris. For some of these platforms, MDSplus packaging has been broken into functional modules so users can pick and choose which MDSplus features they want to install. An added feature to the latest Linux based platforms is the use of package dependencies. When installing MDSplus from the package repositories, any additional required packages used by MDSplus will be installed automatically greatly simplifying the installation of MDSplus. This paper will describe the MDSplus package automated build and distribution system.

  6. Thermal energy storage for a space solar dynamic power system (United States)

    Faget, N. M.; Fraser, W. M., Jr.; Simon, W. E.


    In the past, NASA has employed solar photovoltaic devices for long-duration missions. Thus, the Skylab system has operated with a silicon photovoltaic array and a nickel-cadmium electrochemical system energy storage system. Difficulties regarding the employment of such a system for the larger power requirements of the Space Station are related to a low orbit system efficiency and the large weight of the battery. For this reason the employment of a solar dynamic power system (SDPS) has been considered. The primary components of an SDPS include a concentrating mirror, a heat receiver, a thermal energy storage (TES) system, a thermodynamic heat engine, an alternator, and a heat rejection system. The heat-engine types under consideration are a Brayton cycle engine, an organic Rankine cycle engine, and a free-piston/linear-alternator Stirling cycle engine. Attention is given to a system description, TES integration concepts, and a TES technology assessment.

  7. Concentration and particle size distribution of polycyclic aromatic hydrocarbons formed by thermal cooking. (United States)

    Saito, E; Tanaka, N; Miyazaki, A; Tsuzaki, M


    The concentration and particle size distribution of 19 major polycyclic aromatic hydrocarbons (PAHs) emitted by thermal cooking were investigated. Corn, trout, beef, prawns, and pork were selected for grilling. The PAHs in the oil mist emitted when the food was grilled were collected according to particle size range and analysed by GC/MS. Much higher concentrations of PAHs were detected in the oil mist emitted by grilled pork, trout, and beef samples, which were rich in fat. The main components of the cooking exhaust were 3- and 4-ring PAHs, regardless of food type. The particle size distribution showed that almost all the PAHs were concentrated in particles with diameters of particles with diameters of 90% of the PAHs would reach the alveolar region of the lungs. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Synoptic thermal and oceanographic parameter distributions in the New York Bight Apex (United States)

    Johnson, R. W.; Bahn, G. S.; Thomas, J. P.


    Concurrent surface water measurements made from a moving oceanographic research vessel were used to calibrate and interpret remotely sensed data collected over a plume in the New York Bight Apex on 23 June 1977. Multiple regression techniques were used to develop equations to map synoptic distributions of chlorophyll a and total suspended matter in the remotely sensed scene. Thermal (which did not have surface calibration values) and water quality parameter distributions indicated a cold mass of water in the Bight Apex with an overflowing nutrient-rich warm water plume that originated in the Sandy Hook Bay and flowed south near the New Jersey shoreline. Data analysis indicates that remotely sensed data may be particularly useful for studying physical and biological processes in the top several metres of surface water at plume boundaries.


    Directory of Open Access Journals (Sweden)

    Antônio G.N. Novaes


    Full Text Available The temperature of refrigerated products along the distribution process must be kept within close limits to ensure optimum food safety levels and high product quality. The variation of product temperature along the vehicle routing sequence is represented by non-linear functions. The temperature variability is also correlated with the time required for the refrigerated unit to recover after cargo unloading, due to the cargo discharging process. The vehicle routing optimization methods employed in traditional cargo distribution problems are generally based on the Travelling Salesman Problem with the objective of minimizing travelled distance or time. The thermal quality of routing alternatives is evaluated in this analysis with Process Capability Indices (PCI. Since temperature does not vary linearly with time, a Simulated Annealing algorithm was developed to get the optimal solution in which the minimum vehicle traveling distance is searched, but respecting the quality level expressed by a required minimum PCI value.

  10. Thermal energy storage systems using fluidized bed heat exchangers (United States)

    Ramanathan, V.; Weast, T. E.; Ananth, K. P.


    The viability of using fluidized bed heat exchangers (FBHX) for thermal energy storage (TES) in applications with potential for waste heat recovery was investigated. Of the candidate applications screened, cement plant rotary kilns and steel plant electric arc furnaces were identified, via the chosen selection criteria, as having the best potential for successful use of FBHX/TES system. A computer model of the FBHX/TES systems was developed and the technical feasibility of the two selected applications was verified. Economic and tradeoff evaluations in progress for final optimization of the systems and selection of the most promising system for further concept validation are described.

  11. Git as an Encrypted Distributed Version Control System (United States)


    implementation, Git Virtual Vault (GV2), for users of Git to work on sensitive projects with repositories located in unsecure distributed environments...increasingly popular as software projects are often developed in physically distributed work environments [4]. Git is one such distributed version control...Distributed version control systems are becoming increasingly popular as software projects are often developed in physically distributed work environments

  12. The linewidth of distributed feedback resonators: the combined effect of thermally induced chirp and gain narrowing (United States)

    Kores, Cristine C.; Geskus, Dimitri; Ismail, Nur; Dijkstra, Meindert; Bernhardi, Edward H.; Pollnau, Markus


    Distributed-feedback (DFB) laser resonators are widely recognized for their advantage of generating laser emission with extremely narrow linewidth. Our investigation concerns ytterbium-doped amorphous Al2O3 channel waveguides with a corrugated homogeneous Bragg grating inscribed into its SiO2 top cladding, in which a λ/4 phase-shift provides a resonance and allows for laser emission with a linewidth as narrow as a few kHz. Pump absorption imposes a thermal chirp of the grating period, which has implications for the spectral characteristics of the resonator. Thermal effects on the spectral response of a DFB passive resonator were investigated via simulations using Coupled Mode Theory by considering (i) a constant deviation of the grating period or (ii) a chirp with a linear profile. We report an increase of the resonance linewidth up to 15%. This result is due to two factors, namely changes of the grating reflectivity at the resonance frequency up to 2.4% and of the shift of resonance frequency up to 61 pm due to an accumulated phase shift imposed on the grating by the chirp profile. The linewidth decrease due to gain is on the order of 106, which is a much larger value. Nevertheless, according to the Schawlow-Townes equation the linewidth increase of the passive resonator due to a thermal chirp quadratically increases the laser linewidth.

  13. Nanoscale thermal imaging of dissipation in quantum systems

    CERN Document Server

    Halbertal, Dorri; Shalom, Moshe Ben; Embon, Lior; Shadmi, Nitzan; Anahory, Yonathan; Naren, HR; Sarkar, Jayanta; Uri, Aviram; Ronen, Yuval; Myasoedov, Yury; Levitov, Leonid; Joselevich, Ernesto; Geim, Andre Konstantin; Zeldov, Eli


    Energy dissipation is a fundamental process governing the dynamics of physical, chemical, and biological systems. It is also one of the main characteristics distinguishing quantum and classical phenomena. In condensed matter physics, in particular, scattering mechanisms, loss of quantum information, or breakdown of topological protection are deeply rooted in the intricate details of how and where the dissipation occurs. Despite its vital importance the microscopic behavior of a system is usually not formulated in terms of dissipation because the latter is not a readily measureable quantity on the microscale. Although nanoscale thermometry is gaining much recent interest, the existing thermal imaging methods lack the necessary sensitivity and are unsuitable for low temperature operation required for study of quantum systems. Here we report a superconducting quantum interference nano-thermometer device with sub 50 nm diameter that resides at the apex of a sharp pipette and provides scanning cryogenic thermal se...

  14. Beam-Forming Concentrating Solar Thermal Array Power Systems (United States)

    Cwik, Thomas A. (Inventor); Dimotakis, Paul E. (Inventor); Hoppe, Daniel J. (Inventor)


    The present invention relates to concentrating solar-power systems and, more particularly, beam-forming concentrating solar thermal array power systems. A solar thermal array power system is provided, including a plurality of solar concentrators arranged in pods. Each solar concentrator includes a solar collector, one or more beam-forming elements, and one or more beam-steering elements. The solar collector is dimensioned to collect and divert incoming rays of sunlight. The beam-forming elements intercept the diverted rays of sunlight, and are shaped to concentrate the rays of sunlight into a beam. The steering elements are shaped, dimensioned, positioned, and/or oriented to deflect the beam toward a beam output path. The beams from the concentrators are converted to heat at a receiver, and the heat may be temporarily stored or directly used to generate electricity.

  15. Thermal power systems small power systems application project: Siting issues for solar thermal power plants with small community applications (United States)

    Holbeck, H. J.; Ireland, S. J.


    The siting issues associated with small, dispersed solar thermal power plants for utility/small community applications of less than 10 MWe are reported. Some specific requirements are refered to the first engineering experiment for the Small Power Systems Applications (SPSA) Project. The background for the subsequent issue discussions is provided. The SPSA Project and the requirements for the first engineering experiment are described, and the objectives and scope for the report as a whole. A overview of solar thermal technologies and some technology options are discussed.

  16. Thermal Performance of a Large Low Flow Solar Heating System with a Highly Thermally Stratified Tank

    DEFF Research Database (Denmark)

    Furbo, Simon; Vejen, Niels Kristian; Shah, Louise Jivan


    is performing well in spite of the fact that the solar collectors are far from being orientated optimally. The utilization of the solar radiation on the collectors is higher, 46% in the second year of operation, than for any other system earlier investigated in Denmark, 16%-34%. The reason for the good thermal...... performance and for the excellent utilization of the solar radiation is the high hot-water consumption and the good system design making use of external heat exchangers and stratification inlet pipes.......In year 2000 a 336 m² solar domestic hot water system was built in Sundparken, Elsinore, Denmark. The solar heating system is a low flow system with a 10000 l hot-water tank. Due to the orientation of the buildings half of the solar collectors are facing east, half of the solar collectors...

  17. A prediction model for the effective thermal conductivity of nanofluids considering agglomeration and the radial distribution function of nanoparticles (United States)

    Zheng, Z. M.; Wang, B.


    Conventional heat transfer fluids usually have low thermal conductivity, limiting their efficiency in many applications. Many experiments have shown that adding nanosize solid particles to conventional fluids can greatly enhance their thermal conductivity. To explain this anomalous phenomenon, many theoretical investigations have been conducted in recent years. Some of this research has indicated that the particle agglomeration effect that commonly occurs in nanofluids should play an important role in such enhancement of the thermal conductivity, while some have shown that the enhancement of the effective thermal conductivity might be accounted for by the structure of nanofluids, which can be described using the radial distribution function of particles. However, theoretical predictions from these studies are not in very good agreement with experimental results. This paper proposes a prediction model for the effective thermal conductivity of nanofluids, considering both the agglomeration effect and the radial distribution function of nanoparticles. The resulting theoretical predictions for several sets of nanofluids are highly consistent with experimental data.

  18. High-speed thermal cycling system and method of use (United States)

    Hansen, A.D.A.; Jaklevic, J.M.


    A thermal cycling system and method of use are described. The thermal cycling system is based on the circulation of temperature-controlled water directly to the underside of thin-walled polycarbonate plates. The water flow is selected from a manifold fed by pumps from heated reservoirs. The plate wells are loaded with typically 15-20 microliters of reagent mix for the PCR process. Heat transfer through the thin polycarbonate is sufficiently rapid that the contents reach thermal equilibrium with the water in less than 15 seconds. Complete PCR amplification runs of 40 three-step cycles have been performed in as little as 14.5 minutes, with the results showing substantially enhanced specificity compared to conventional technology requiring run times in excess of 100 minutes. The plate clamping station is designed to be amenable to robotic loading and unloading of the system. It includes a heated lid, thus eliminating the need for mineral oil overlay of the reactants. The present system includes three or more plate holder stations, fed from common reservoirs but operating with independent switching cycles. The system can be modularly expanded. 13 figs.

  19. Optimal capacitor placement in smart distribution systems to improve ...

    African Journals Online (AJOL)

    An energy efficient power distribution network can provide cost-effective and collaborative platform for supporting present and future smart distribution system requirements. Energy efficiency in distribution systems is achieved through reconfiguration of distributed generation and optimal capacitor placement. Though several ...

  20. Three-Dimensional Finite Element Ablative Thermal Response and Thermostructural Design of Thermal Protection Systems (United States)

    Dec, John A.; Braun, Robert D.


    A finite element ablation and thermal response program is presented for simulation of three-dimensional transient thermostructural analysis. The three-dimensional governing differential equations and finite element formulation are summarized. A novel probabilistic design methodology for thermal protection systems is presented. The design methodology is an eight step process beginning with a parameter sensitivity study and is followed by a deterministic analysis whereby an optimum design can determined. The design process concludes with a Monte Carlo simulation where the probabilities of exceeding design specifications are estimated. The design methodology is demonstrated by applying the methodology to the carbon phenolic compression pads of the Crew Exploration Vehicle. The maximum allowed values of bondline temperature and tensile stress are used as the design specifications in this study.

  1. Distributed and Decentralized Control in Fully Distributed Processing Systems. (United States)


    functions appear to be implemented with identical copies resident at each node. Another system based upon a hierarchical organization is the MICRONET ...system [Witt79, Witt80]. MICRONET is a packet switched network of loosely- coupled LSI-11’s which are interconnected by 0.5 Mbyte/sec shared communica...Metc76). Nodes consist of a host and a communication computer. MICROS, the operating system for MICRONET , utilizes a hierarchical control strategy. The

  2. Thermal Vacuum Integrated System Test at B-2 (United States)

    Kudlac, Maureen T.; Weaver, Harold F.; Cmar, Mark D.


    The National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) Plum Brook Station (PBS) Space Propulsion Research Facility, commonly referred to as B-2, is NASA s third largest thermal vacuum facility. It is the largest designed to store and transfer large quantities of liquid hydrogen and liquid oxygen, and is perfectly suited to support developmental testing of chemical propulsion systems as well as fully integrated stages. The facility is also capable of providing thermal-vacuum simulation services to support testing of large lightweight structures, Cryogenic Fluid Management (CFM) systems, electric propulsion test programs, and other In-Space propulsion programs. A recently completed integrated system test demonstrated the refurbished thermal vacuum capabilities of the facility. The test used the modernized data acquisition and control system to monitor the facility during pump down of the vacuum chamber, operation of the liquid nitrogen heat sink (or cold wall) and the infrared lamp array. A vacuum level of 1.3x10(exp -4)Pa (1x10(exp -6)torr) was achieved. The heat sink provided a uniform temperature environment of approximately 77 K (140deg R) along the entire inner surface of the vacuum chamber. The recently rebuilt and modernized infrared lamp array produced a nominal heat flux of 1.4 kW/sq m at a chamber diameter of 6.7 m (22 ft) and along 11 m (36 ft) of the chamber s cylindrical vertical interior. With the lamp array and heat sink operating simultaneously, the thermal systems produced a heat flux pattern simulating radiation to space on one surface and solar exposure on the other surface. The data acquired matched pretest predictions and demonstrated system functionality.

  3. Metal hydride-based thermal energy storage systems (United States)

    Vajo, John J.; Fang, Zhigang


    The invention provides a thermal energy storage system comprising a metal-containing first material with a thermal energy storage density of about 1300 kJ/kg to about 2200 kJ/kg based on hydrogenation; a metal-containing second material with a thermal energy storage density of about 200 kJ/kg to about 1000 kJ/kg based on hydrogenation; and a hydrogen conduit for reversibly transporting hydrogen between the first material and the second material. At a temperature of C. and in 1 hour, at least 90% of the metal is converted to the hydride. At a temperature of C. and in 1 hour, at least 90% of the metal hydride is converted to the metal and hydrogen. The disclosed metal hydride materials have a combination of thermodynamic energy storage densities and kinetic power capabilities that previously have not been demonstrated. This performance enables practical use of thermal energy storage systems for electric vehicle heating and cooling.

  4. Spatial and temporal distribution of ore deposits, in relation with thermal anomalies (United States)

    Harcouet, V.; Bonneville, A.; Guillou-Frottier, L.


    Ore deposits have formed over billion years of Earth's history with a discontinuous distribution in time and space.In time, their formation is episodical, and the data concerning the main deposit types show an alternation of periods with mineralisation followed by time gaps, with no large amount of ore generation. The "Snowball Earth" theory suggests that Banded Iron formations (BIF) are in relation with periods of intense global glaciations of Paleoproterozoic (2500-1600 Ma) and Neoproterozoic (1000-540 Ma) ages. During global glaciations, surface temperatures were of the order of -50°C and an ice layer of about 1km covered almost the entire Earth. We have performed analytical and numerical modelling of such events that shows the development of high thermal anomalies in the crust. These anomalies can reach several tens of degrees for a time lapse that depends on the duration of the glaciation. If the thermal impact is clear, the mechanical impact of the glaciations on the crustal rocks still needs to be evaluated to precisely assess the role of glaciations as a possible cause to some of the gaps in the temporal distribution of ore deposits.Ore deposits have also a heterogeneous spatial distribution: they are located in specific places of the Earth's crust, where thermo-mechanical and hydrothermal conditions have triggered their formation. The temperature pattern corresponding to these cases can prove to be particularly favourable to ore deposits. A good example of such deposits, is the Ashanti belt in Ghana of which we present a detailed study. It is the key district of gold mineralisation in the Paleoproterozoic terrane of West Africa. This is the second giant concentration of gold deposits after South Africa with a potential of about 2500 tons of gold. The Eburnean orogeny operated between 2.13 and 1.98 Ga. Two tectonic phases affected the area, a period of thrusting and a second one corresponding to transcurrent tectonism. A numerical modelling was performed

  5. Physical, thermal and structural properties of Calcium Borotellurite glass system

    Energy Technology Data Exchange (ETDEWEB)

    Paz, E.C. [CCSST – UFMA, Imperatriz, MA (Brazil); IFMA, Açailândia, MA (Brazil); Dias, J.D.M. [CCSST – UFMA, Imperatriz, MA (Brazil); Melo, G.H.A. [CCSST – UFMA, Imperatriz, MA (Brazil); IFMA, Imperatriz, MA (Brazil); Lodi, T.A. [CCSST – UFMA, Imperatriz, MA (Brazil); Carvalho, J.O. [CCSST – UFMA, Imperatriz, MA (Brazil); IFTO, Araguaína, TO (Brazil); Façanha Filho, P.F.; Barboza, M.J.; Pedrochi, F. [CCSST – UFMA, Imperatriz, MA (Brazil); Steimacher, A., E-mail: [CCSST – UFMA, Imperatriz, MA (Brazil)


    In this work the glass forming ability in Calcium Borotellurite (CBTx) glass system was studied. Six glass samples were prepared by melt-quenching technique and the obtained samples are transparent, lightly yellowish, with no visible crystallites. The structural studies were carried out by using XRD, FTIR, Raman Spectra, density measurements, and the thermal analysis by using DTA and specific heat. The results are discussed in terms of tellurium oxide content and their changes in structural and thermal properties of glass samples. The addition of TeO{sub 2} increased the density and thermal stability values and decreased glass transition temperature (Tg). Raman and FTIR spectroscopies indicated that the network structure of CBTx glasses is formed by BO{sub 3}, BO{sub 4}, TeO{sub 3}, TeO{sub 3+1} and TeO{sub 4} units. CBTx system showed good glass formation ability and good thermal stability, which make CBTx glasses suitable for manufacturing process and a candidate for rare-earth doping for several optical applications. - Highlights: • Glass forming ability on Calcium Borotellurite system was studied. • The glass structure was investigated by XRD, Raman and FTIR. • The glass network structure of the CBTx glasses is formed by BO{sub 3}, BO{sub 4}, TeO{sub 3}, TeO{sub 3+1} and TeO{sub 4} units. • The density and thermal stability of the CBTx glass decreases with TeO{sub 2} while the Cp and the Tg decreases. • The obtained CBTx glasses are suitable for manufacturing process and rare-earth doping for several optical applications.

  6. Thermal Contraction Crack Polygon Classification and Distribution: Morphological Variations in Northern Hemisphere Patterned Ground (United States)

    Levy, J.; Head, J.; Marchant, D.


    Polygonally patterned ground has been identified on Mars since the Viking era [1], and has long been interpreted as a signal of the presence of subsurface ice deposits [2-4]. The origin of ice in the shallow martian subsurface, whether by cyclical vapour diffusion or primary deposition, remains an area of active inquiry [5- 9]. Recent modelling suggests that high-latitude terrains on Mars may support buried ice sheets and glaciers, produced by direct atmospheric deposition within the past 5 My [5], overlain by a sublimation lag deposit ranging in thickness from 10s to 100s of cm [8]. These results are consistent with coarse-resolution (100s of km per pixel) neutron-spectrometer results correlating highlatitude patterned ground with subsurface water [4, 10, 11], as well as a suite of geomorphological observations linking young terrains to recently deposited, ice-rich units [5-7]. Polygon classification in terrestrial polar environments is based on morphology, structure, and origin processes. On Earth, thermal contraction crack polygons can be divided into three types: ice-wedge, sand-wedge, and sublimation polygons; each of which forms under a unique set of climate and substrate-composition conditions [12-14]. Although the thermal contraction cracking process under martian conditions is well understood [15], classification systems for polygonally patterned ground on Mars have until now relied primarily on imaging data at resolutions comparable to the scale of the polygons of interest [3]. We build on the identification of sublimation polygons in the NASA Phoenix landing area [16], and preliminary classification of polygons into morphological species (groups distinguishable by characteristic surface morphologies) [17] across the northern hemisphere of Mars. We present an integrated assessment of martian polygon morphological variation as a function of latitude, and suggest links between polygon morphology, origin timing, and global climate conditions. This analysis

  7. A Thermal Management System Using Ammonium Carbamate as an Endothermic Heat Sink (POSTPRINT) (United States)


    introduce and demonstrate a thermal management system (TMS) architecture integrating a vapor compression heat pump, phase change thermal energy...Thermal Engineering journal homepage: www.elsevier .com/locate /apthermengA thermal management system using ammonium carbamate as an endothermic heat...AFRL-RQ-WP-TP-2017-0159 A THERMAL MANAGEMENT SYSTEM USING AMMONIUM CARBAMATE AS AN ENDOTHERMIC HEAT SINK (POSTPRINT) Nicholas P

  8. Experiment Investigation on Electrical and Thermal Performances of a Semitransparent Photovoltaic/Thermal System with Water Cooling

    Directory of Open Access Journals (Sweden)

    Guiqiang Li


    Full Text Available Different from the semitransparent building integrated photovoltaic/thermal (BIPV/T system with air cooling, the semitransparent BIPV/T system with water cooling is rare, especially based on the silicon solar cells. In this paper, a semitransparent photovoltaic/thermal system (SPV/T with water cooling was set up, which not only would provide the electrical power and hot water, but also could attain the natural illumination for the building. The PV efficiency, thermal efficiency, and exergy analysis were all adopted to illustrate the performance of SPV/T system. The results showed that the PV efficiency and the thermal efficiency were about 11.5% and 39.5%, respectively, on the typical sunny day. Furthermore, the PV and thermal efficiencies fit curves were made to demonstrate the SPV/T performance more comprehensively. The performance analysis indicated that the SPV/T system has a good application prospect for building.

  9. Simulation of warehousing and distribution systems

    Directory of Open Access Journals (Sweden)

    Drago Pupavac


    Full Text Available The modern world abounds in simulation models. Thousands of organizations use simulation models to solve business problems. Problems in micro logistics systems are a very important segment of the business problems that can be solved by a simulation method. In most cases logistics simulation models should be developed with a purpose to evaluate the performance of individual value-adding indirect resources of logistics system, their possibilities and operational advantages as well as the flow of logistics entities between the plants, warehouses, and customers. Accordingly, this scientific paper elaborates concisely the theoretical characteristics of simulation models and the domains in which the simulation approach is best suited in logistics. Special attention is paid to simulation modeling of warehousing and distribution subsystems of logistic system and there is an example of spreadsheet application in the function of simulated demand for goods from warehouse. Apart from simulation model induction and deduction methods, the description method and a method of information modeling are applied.

  10. Distributed gas detection system and method

    Energy Technology Data Exchange (ETDEWEB)

    Challener, William Albert; Palit, Sabarni; Karp, Jason Harris; Kasten, Ansas Matthias; Choudhury, Niloy


    A distributed gas detection system includes one or more hollow core fibers disposed in different locations, one or more solid core fibers optically coupled with the one or more hollow core fibers and configured to receive light of one or more wavelengths from a light source, and an interrogator device configured to receive at least some of the light propagating through the one or more solid core fibers and the one or more hollow core fibers. The interrogator device is configured to identify a location of a presence of a gas-of-interest by examining absorption of at least one of the wavelengths of the light at least one of the hollow core fibers.

  11. Improving Newspaper Distribution with Mobile Field Systems

    Directory of Open Access Journals (Sweden)

    Jonas Rehn


    Full Text Available In this paper the information, which is exchanged among the field workers and the operation center in morning newspaper distribution, is described. This information exchange is made via telephone calls and stationary computers, but is also paper based. This study was conducted to find how this information exchange could be improved with a mobile field system and handheld electronic devices.The results showed that there are technologies available today that can be used for electronic information exchange and that this could improve the safety for the truck drivers and carriers. Moreover, the time for solving problems will increase when the information exchange is improved. However, this electronic information exchange will require new working methods for the personnel involved.

  12. Thermal Design for Extra-Terrestrial Regenerative Fuel Cell System (United States)

    Gilligan, R.; Guzik, M.; Jakupca, I.; Bennett, W.; Smith, P.; Fincannon, J.


    The Advanced Exploration Systems (AES) Advanced Modular Power Systems (AMPS) Project is investigating different power systems for various lunar and Martian mission concepts. The AMPS Fuel Cell (FC) team has created two system-level models to evaluate the performance of regenerative fuel cell (RFC) systems employing different fuel cell chemistries. Proton Exchange Membrane fuel cells PEMFCs contain a polymer electrolyte membrane that separates the hydrogen and oxygen cavities and conducts hydrogen cations (protons) across the cell. Solid Oxide fuel cells (SOFCs) operate at high temperatures, using a zirconia-based solid ceramic electrolyte to conduct oxygen anions across the cell. The purpose of the modeling effort is to down select one fuel cell chemistry for a more detailed design effort. Figures of merit include the system mass, volume, round trip efficiency, and electrolyzer charge power required. PEMFCs operate at around 60 C versus SOFCs which operate at temperatures greater than 700 C. Due to the drastically different operating temperatures of the two chemistries the thermal control systems (TCS) differ. The PEM TCS is less complex and is characterized by a single pump cooling loop that uses deionized water coolant and rejects heat generated by the system to the environment via a radiator. The solid oxide TCS has its own unique challenges including the requirement to reject high quality heat and to condense the steam produced in the reaction. This paper discusses the modeling of thermal control systems for an extraterrestrial RFC that utilizes either a PEM or solid oxide fuel cell.

  13. Distributed generation and centralized power system in Thailand

    DEFF Research Database (Denmark)

    Sukkumnoed, Decharut


    The paper examines and discusses conflicts between the development of distributed power and centralized power system.......The paper examines and discusses conflicts between the development of distributed power and centralized power system....

  14. Low-carbon benefit analysis on DG penetration distribution system

    National Research Council Canada - National Science Library

    GE, Shaoyun; XU, Li; LIU, Hong; FANG, Jian


    .... This paper proposes a pseudo-sequential Monte Carlo simulation method for the low-carbon benefit evaluation of distribution system including distributed wind turbines, solar array and battery energy storage systems...

  15. Distributed generation and centralized power system in Thailand

    DEFF Research Database (Denmark)

    Sukkumnoed, Decharut

    The paper examines and discusses conflicts between the development of distributed power and centralized power system in Thailand.......The paper examines and discusses conflicts between the development of distributed power and centralized power system in Thailand....

  16. Quantum chaos and thermalization in isolated systems of interacting particles

    Energy Technology Data Exchange (ETDEWEB)

    Borgonovi, F., E-mail: [Dipartimento di Matematica e Fisica and Interdisciplinary Laboratories for Advanced Materials Physics, Universitá Cattolica, via Musei 41, 25121 Brescia, and INFN, Sezione di Pavia (Italy); Izrailev, F.M., E-mail: [Instituto de Física, Universidad Autónoma de Puebla, Apt. Postal J-48, Puebla, Pue., 72570 (Mexico); NSCL and Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824-1321 (United States); Santos, L.F., E-mail: [Department of Physics, Yeshiva University, 245 Lexington Ave, New York, NY 10016 (United States); Zelevinsky, V.G., E-mail: [NSCL and Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824-1321 (United States)


    This review is devoted to the problem of thermalization in a small isolated conglomerate of interacting constituents. A variety of physically important systems of intensive current interest belong to this category: complex atoms, molecules (including biological molecules), nuclei, small devices of condensed matter and quantum optics on nano- and micro-scale, cold atoms in optical lattices, ion traps. Physical implementations of quantum computers, where there are many interacting qubits, also fall into this group. Statistical regularities come into play through inter-particle interactions, which have two fundamental components: mean field, that along with external conditions, forms the regular component of the dynamics, and residual interactions responsible for the complex structure of the actual stationary states. At sufficiently high level density, the stationary states become exceedingly complicated superpositions of simple quasiparticle excitations. At this stage, regularities typical of quantum chaos emerge and bring in signatures of thermalization. We describe all the stages and the results of the processes leading to thermalization, using analytical and massive numerical examples for realistic atomic, nuclear, and spin systems, as well as for models with random parameters. The structure of stationary states, strength functions of simple configurations, and concepts of entropy and temperature in application to isolated mesoscopic systems are discussed in detail. We conclude with a schematic discussion of the time evolution of such systems to equilibrium.

  17. Layered Thermal Insulation Systems for Industrial and Commercial Applications (United States)

    Fesmire, James E.


    From the high performance arena of cryogenic equipment, several different layered thermal insulation systems have been developed for industrial and commercial applications. In addition to the proven areas in cold-work applications for piping and tanks, the new Layered Composite Insulation for Extreme Environments (LCX) has potential for broader industrial use as well as for commercial applications. The LCX technology provides a unique combination of thermal, mechanical, and weathering performance capability that is both cost-effective and enabling. Industry applications may include, for example, liquid nitrogen (LN2) systems for food processing, liquefied natural gas (LNG) systems for transportation or power, and chilled water cooling facilities. Example commercial applications may include commercial residential building construction, hot water piping, HVAC systems, refrigerated trucks, cold chain shipping containers, and a various consumer products. The LCX system is highly tailorable to the end-use application and can be pre-fabricated or field assembled as needed. Product forms of LCX include rigid sheets, semi-flexible sheets, cylindrical clam-shells, removable covers, or flexible strips for wrapping. With increasing system control and reliability requirements as well as demands for higher energy efficiencies, thermal insulation in harsh environments is a growing challenge. The LCX technology grew out of solving problems in the insulation of mechanically complex cryogenic systems that must operate in outdoor, humid conditions. Insulation for cold work includes equipment for everything from liquid helium to chilled water. And in the middle are systems for LNG, LN2, liquid oxygen (LO2), liquid hydrogen (LH2) that must operate in the ambient environment. Different LCX systems have been demonstrated for sub-ambient conditions but are capable of moderately high temperature applications as well.

  18. A Chance-Constrained Economic Dispatch Model in Wind-Thermal-Energy Storage System

    Directory of Open Access Journals (Sweden)

    Yanzhe Hu


    Full Text Available As a type of renewable energy, wind energy is integrated into the power system with more and more penetration levels. It is challenging for the power system operators (PSOs to cope with the uncertainty and variation of the wind power and its forecasts. A chance-constrained economic dispatch (ED model for the wind-thermal-energy storage system (WTESS is developed in this paper. An optimization model with the wind power and the energy storage system (ESS is first established with the consideration of both the economic benefits of the system and less wind curtailments. The original wind power generation is processed by the ESS to obtain the final wind power output generation (FWPG. A Gaussian mixture model (GMM distribution is adopted to characterize the probabilistic and cumulative distribution functions with an analytical expression. Then, a chance-constrained ED model integrated by the wind-energy storage system (W-ESS is developed by considering both the overestimation costs and the underestimation costs of the system and solved by the sequential linear programming method. Numerical simulation results using the wind power data in four wind farms are performed on the developed ED model with the IEEE 30-bus system. It is verified that the developed ED model is effective to integrate the uncertain and variable wind power. The GMM distribution could accurately fit the actual distribution of the final wind power output, and the ESS could help effectively decrease the operation costs.

  19. A thermally driven differential mutation approach for the structural optimization of large atomic systems (United States)

    Biswas, Katja


    A computational method is presented which is capable to obtain low lying energy structures of topological amorphous systems. The method merges a differential mutation genetic algorithm with simulated annealing. This is done by incorporating a thermal selection criterion, which makes it possible to reliably obtain low lying minima with just a small population size and is suitable for multimodal structural optimization. The method is tested on the structural optimization of amorphous graphene from unbiased atomic starting configurations. With just a population size of six systems, energetically very low structures are obtained. While each of the structures represents a distinctly different arrangement of the atoms, their properties, such as energy, distribution of rings, radial distribution function, coordination number, and distribution of bond angles, are very similar.

  20. Late Lutetian Thermal Maximum—Crossing a Thermal Threshold in Earth's Climate System? (United States)

    Westerhold, T.; Röhl, U.; Donner, B.; Frederichs, T.; Kordesch, W. E. C.; Bohaty, S. M.; Hodell, D. A.; Laskar, J.; Zeebe, R. E.


    Recognizing and deciphering transient global warming events triggered by massive release of carbon into Earth's ocean-atmosphere climate system in the past are important for understanding climate under elevated pCO2 conditions. Here we present new high-resolution geochemical records including benthic foraminiferal stable isotope data with clear evidence of a short-lived (30 kyr) warming event at 41.52 Ma. The event occurs in the late Lutetian within magnetochron C19r and is characterized by a ˜2°C warming of the deep ocean in the southern South Atlantic. The magnitudes of the carbon and oxygen isotope excursions of the Late Lutetian Thermal Maximum are comparable to the H2 event (53.6 Ma) suggesting a similar response of the climate system to carbon cycle perturbations even in an already relatively cooler climate several million years after the Early Eocene Climate Optimum. Coincidence of the event with exceptionally high insolation values in the Northern Hemisphere at 41.52 Ma might indicate that Earth's climate system has a thermal threshold. When this tipping point is crossed, rapid positive feedback mechanisms potentially trigger transient global warming. The orbital configuration in this case could have caused prolonged warm and dry season leading to a massive release of terrestrial carbon into the ocean-atmosphere system initiating environmental change.