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1

Heat Pipe Thermal Conditioning Panel  

NASA Technical Reports Server (NTRS)

The technology involved in designing and fabricating a heat pipe thermal conditioning panel to satisfy a broad range of thermal control system requirements on NASA spacecraft is discussed. The design specifications were developed for a 30 by 30 inch heat pipe panel. The fundamental constraint was a maximum of 15 gradient from source to sink at 300 watts input and a flux density of 2 watts per square inch. The results of the performance tests conducted on the panel are analyzed.

Saaski, E. W.

1973-01-01

2

INNOVATIVE THERMAL DESTRUCTION TECHNOLOGIES  

EPA Science Inventory

Ten innovative technologies for thermally destroying hazardous wastes were selected and described in this paper. hese technologies were either supported by EPA's RCRA or SARA programs or developed by industry since 1980. wo of the important criteria used in selecting these techno...

3

Solar thermal technology  

NASA Astrophysics Data System (ADS)

The accomplishments and progress of the US Department of energy solar thermal technology (STT) program during FY 1983 are documented. The focus of the STT program is research and development leading to the commercial readiness of three primary solar thermal concepts: the central receiver, parabolic dish, and parabolic trough. The hemispherical bowl and salt-gradient solar pond are also being studied. This development effort is complemented by numerous research and planning activities. A brief description of each technology and highlights of the fiscal year's technical activities is given. FY 1983 accomplishments are enumerated and a bibliography, list of contacts, acronyms, and definitions of terms relevant to solar thermal technology and the STT program are included.

1984-08-01

4

Centaur Propellant Thermal Conditioning Study  

NASA Technical Reports Server (NTRS)

A wicking investigation revealed that passive thermal conditioning was feasible and provided considerable weight advantage over active systems using throttled vent fluid in a Centaur D-1s launch vehicle. Experimental wicking correlations were obtained using empirical revisions to the analytical flow model. Thermal subcoolers were evaluated parametrically as a function of tank pressure and NPSP. Results showed that the RL10 category I engine was the best candidate for boost pump replacement and the option showing the lowest weight penalty employed passively cooled acquisition devices, thermal subcoolers, dry ducts between burns and pumping of subcooler coolant back into the tank. A mixing correlation was identified for sizing the thermodynamic vent system mixer. Worst case mixing requirements were determined by surveying Centaur D-1T, D-1S, IUS, and space tug vehicles. Vent system sizing was based upon worst case requirements. Thermodynamic vent system/mixer weights were determined for each vehicle.

Blatt, M. H.; Pleasant, R. L.; Erickson, R. C.

1976-01-01

5

Monitoring Thermal Conditions in Footwear  

NASA Astrophysics Data System (ADS)

Thermal conditions inside the foot were evaluated on a volunteer subject. We have designed and constructed an electronic system which can monitors temperature and humidity of the foot inside the shoe. The data is stored in a battery-powered device for later uploading to a host computer for data analysis. The apparatus potentially can be used to provide feedback to patients who are prone to having skin breakdowns.

Silva-Moreno, Alejandra. A.; Lopez Vela, Martín; Alcalá Ochoa, Noe

2006-09-01

6

High temperature solar thermal technology  

NASA Astrophysics Data System (ADS)

Some advanced technology concepts under development for high-temperature solar thermal energy systems to achieve significant energy cost reductions and performance gains and thus promote the application of solar thermal power technology are presented. Consideration is given to the objectives, current efforts and recent test and analysis results in the development of high-temperature (950-1650 C) ceramic receivers, thermal storage module checker stoves, and the use of reversible chemical reactions to transport collected solar energy. It is pointed out that the analysis and testing of such components will accelerate the commercial deployment of solar energy.

Leibowitz, L. P.; Hanseth, E. J.; Peelgren, M. L.

1980-11-01

7

High temperature solar thermal technology  

NASA Technical Reports Server (NTRS)

Some advanced technology concepts under development for high-temperature solar thermal energy systems to achieve significant energy cost reductions and performance gains and thus promote the application of solar thermal power technology are presented. Consideration is given to the objectives, current efforts and recent test and analysis results in the development of high-temperature (950-1650 C) ceramic receivers, thermal storage module checker stoves, and the use of reversible chemical reactions to transport collected solar energy. It is pointed out that the analysis and testing of such components will accelerate the commercial deployment of solar energy.

Leibowitz, L. P.; Hanseth, E. J.; Peelgren, M. L.

1980-01-01

8

Solar thermal desalination technologies  

Microsoft Academic Search

The use of solar energy in thermal desalination processes is one of the most promising applications of the renewable energies. Solar desalination can either be direct; use solar energy to produce distillate directly in the solar collector, or indirect; combining conventional desalination techniques, such as multistage flash desalination (MSF), vapor compression (VC), reverse osmosis (RO), membrane distillation (MD) and electrodialysis,

Hazim Mohameed Qiblawey; Fawzi Banat

2008-01-01

9

Solar thermal technology  

NASA Astrophysics Data System (ADS)

This annual evaluation report provides the accomplishments and progress of government-funded activities initiated, renewed, or completed during Fiscal Year 1985 (October 1, 1984 through September 30, 1985). It highlights the program tasks conducted by participating national laboratories and by contracting industrial academic, or other research institutions. The focus of the STT Program is research and development leading to the commercial readiness of four primary solar thermal concepts: (1) central receiver; (2) parabolic dish; (3) parabolic trough; and (4) hemispherical bowl.

1986-08-01

10

Thermal neutron analysis technology  

NASA Astrophysics Data System (ADS)

This paper describes the application of thermal neutron analysis (TNA) to a variety of non-intrusive detection problems. TNA is based on the analysis of neutron capture gamma rays from particular elements which are indicative of the material of interest. TNA was developed for detection of concealed explosives in airline luggage during the late 1980s and is now being investigated and tested for new applications. These applications include detection of drugs in passenger luggage, detection of explosives and drugs in small packages, detection of liquid explosives in bottles, and detection of buried land mines and unexploded ordnance. For explosive, land mine and UXO detection, the TNA is based on the 10.8 MeV capture gamma ray from nitrogen, whose high density is uniquely characteristic of modern high explosives. For detection of drugs, the use of capture gamma ray signals from both hydrogen and chlorine (from hydrochloride drug salt) have been investigated, and a specific set of features based on these gamma ray signals selected for the detection algorithm. The research and test results of this wider application of TNA, carried out over the last year are described.

Brown, Douglas R.; Gozani, Tsahi

1997-02-01

11

Conceptual Thermal Treatment Technologies Feasibility Study  

SciTech Connect

This report presents a conceptual Thermal Treatment Technologies Feasibility Study (FS) for the Savannah River Site (SRS) focusing exclusively on thermal treatment technologies for contaminated soil, sediment, or sludge remediation projects.

Suer, A.

1996-02-28

12

Thermally-Choked Combustor Technology  

NASA Technical Reports Server (NTRS)

A program is underway to demonstrate the practical feasibility of thermally-choked combustor technology with particular emphasis on rocket propulsion applications. Rather than induce subsonic to supersonic flow transition in a geometric throat, the goal is to create a thermal throat by adding combustion heat in a diverging nozzle. Such a device would have certain advantages over conventional flow accelerators assuming that the pressure loss due to heat addition does not severely curtail propulsive efficiency. As an aid to evaluation, a generalized one-dimensional compressible flow analysis tool was constructed. Simplified calculations indicate that the process is fluid dynamically and thermodynamically feasible. Experimental work is also being carried out in an attempt to develop, assuming an array of practical issues are surmountable, a practical bench-scale demonstrator using high flame speed H2/O2 combustibles.

Knuth, William H.; Gloyer, P.; Goodman, J.; Litchford, R. J.

1993-01-01

13

Advances in solar thermal electricity technology  

Microsoft Academic Search

Various advanced solar thermal electricity technologies are reviewed with an emphasis on new technology and new market approaches.In single-axis tracking technology, the conventional parabolic trough collector is the mainstream established technology and is under continued development but is soon to face competition from two linear Fresnel reflector (LFR) technologies, the CLFR and Solarmundo. A Solarmundo prototype has been built in

D. Mills

2004-01-01

14

Status of thermal spray technology in japan  

Microsoft Academic Search

This article summarizes the present status and prospects for future progress of the thermal spraying business and technology\\u000a in Japan. Organizations that have supported thermal spraying business and technology consist of coating contract shops, producers\\u000a and suppliers of spray equipment and consumables, and large companies that have been using thermal spray technology in their\\u000a production lines. Moreover, out-side, noncommercial organizations

K. Tani; H. Nakahira

1992-01-01

15

High Performance Thermal Interface Technology Overview  

E-print Network

An overview on recent developments in thermal interfaces is given with a focus on a novel thermal interface technology that allows the formation of 2-3 times thinner bondlines with strongly improved thermal properties at lower assembly pressures. This is achieved using nested hierarchical surface channels to control the particle stacking with highly particle-filled materials. Reliability testing with thermal cycling has also demonstrated a decrease in thermal resistance after extended times with longer overall lifetime compared to a flat interface.

R. Linderman; T. Brunschwiler; B. Smith; B. Michel

2008-01-07

16

NASA/Goddard Thermal Technology Overview 2012  

NASA Technical Reports Server (NTRS)

New Technology program is underway at NASA NASA/GSFC's primary mission of science satellite development is healthy and vibrant, although new missions are scarce Future mission applications promise to be thermally challenging Direct technology funding is still very restricted

Butler, Dan; Swanson, Ted

2012-01-01

17

Advanced thermal management technologies for defense electronics  

NASA Astrophysics Data System (ADS)

Thermal management technology plays a key role in the continuing miniaturization, performance improvements, and higher reliability of electronic systems. For the past decade, and particularly, the past 4 years, the Defense Advanced Research Projects Agency (DARPA) has aggressively pursued the application of micro- and nano-technology to reduce or remove thermal constraints on the performance of defense electronic systems. The DARPA Thermal Management Technologies (TMT) portfolio is comprised of five technical thrust areas: Thermal Ground Plane (TGP), Microtechnologies for Air-Cooled Exchangers (MACE), NanoThermal Interfaces (NTI), Active Cooling Modules (ACM), and Near Junction Thermal Transport (NJTT). An overview of the TMT program will be presented with emphasis on the goals and status of these efforts relative to the current State-of-the-Art. The presentation will close with future challenges and opportunities in the thermal management of defense electronics.

Bloschock, Kristen P.; Bar-Cohen, Avram

2012-05-01

18

NASA thermal control technologies for robotic spacecraft  

Microsoft Academic Search

Technology development is inevitably a dynamic process in search of an elusive goal. It is never truly clear whether the need for a particular technology drives its development, or the existence of a new capability initiates new applications. Technology development for the thermal control of spacecraft presents an excellent example of this situation. Nevertheless, it is imperative to have a

Theodore D. Swanson; Gajanana C. Birur

2003-01-01

19

The future of thermal spray technology  

SciTech Connect

Thermal spray technology is emerging as an important processing tool for both surface protection and advanced materials forming. Despite the technology having been in use for over 100 years, much of its advancement, driven by aerospace applications, has occurred in the past 15 years. Increased understanding of process/structure/property relationships has resulted in the growing application of thermal spray coating technology resulting in new processes; for example, low-pressure plasma spray, high-velocity oxyfuel (HVOF) spray and reactive plasma spray. New equipment, automation and materials have been introduced. This article reviews many of the commercial thermal spray processes, borrowing from educational programs at ASM International and the Hobart Institute of Welding Technology, and reviews the applications and growth potential for emerging thermal spray processing technologies. A review of the needs in education and standardization and comparisons to programs on other countries is also presented.

Smith, R.W. (Materials Resources, Inc., Blue Bell, PA (United States)); Fast, R.D. (Hobart Inst. of Welding Technology, Troy, OH (United States))

1994-07-01

20

UPDATE OF INNOVATIVE THERMAL DESTRUCTION TECHNOLOGIES  

EPA Science Inventory

Five innovative technologies for thermally destroying hazardous wastes were selected and described in the paper. They are Oxygen-Enriched Incineration, Westinghouse/O'Connor Combustor, Circulating Bed Combustion, Infrared System, and Plasma Arc. Two important criteria used in sel...

21

Advanced thermal control technology for commercial applications  

NASA Technical Reports Server (NTRS)

A number of the technologies previously developed for the thermal control of spacecraft have found their way into commercial application. Specialized coatings and heat pipes are but two examples. The thermal control of current and future spacecraft is becoming increasingly more demanding, and a variety of new technologies are being developed to meet these needs. Closed two-phase loops are perceived to be the answer to many of the new requirements. All of these technologies are discussed, and their spacecraft and current terrestrial applications are summarized.

Swanson, Theodore D.

1991-01-01

22

Proceedings of the Solar Thermal Technology Conference  

NASA Astrophysics Data System (ADS)

The Solar Thermal Technology Conference was held on August 26 to 28, 1987, at the Marriott Hotel, Albuquerque, New Mexico. The meeting was sponsored by the United States Department of Energy and Sandia National Laboratories. Topics covered during the conference included a status summary of the Sandia Solar Thermal Development Project, perspectives on central and distributed receiver technology including energy collection and conversion technologies, systems analyses and applications experiments. The proceedings contain summaries (abstracts and principal visual aids) of the presentations made at the conference.

Tyner, C. E.

1987-08-01

23

Commercial application of thermal protection system technology  

NASA Technical Reports Server (NTRS)

The thermal protection system process technology is examined which is used in the manufacture of the External Tank for the Space Shuttle system and how that technology is applied by private business to create new products, new markets, and new American jobs. The term 'technology transfer' means different things to different people and has become one of the buzz words of the 1980s and 1990s. Herein, technology transfer is defined as a means of transferring technology developed by NASA's prime contractors to public and private sector industries.

Dyer, Gordon L.

1991-01-01

24

MSFC nuclear thermal propulsion technology program  

NASA Technical Reports Server (NTRS)

Viewgraphs on non-nuclear materials assessment, nuclear thermal propulsion (NTP) turbomachinery technologies, and high temperature superconducting magnetic bearing technology are presented. The objective of the materials task is to identify and evaluate candidate materials for use in NTP turbomachinery and propellant feed system applications. The objective of the turbomachinery technology task is to develop and validate advanced turbomachinery technologies at the component and turbopump assembly levels. The objective of the high temperature superconductors (HTS) task is to develop and validate advanced technology for HTS passive magnetic/hydrostatic bearing.

Swint, Shane

1993-01-01

25

Thermal conditions in the Anadarko basin, Oklahoma  

SciTech Connect

Heat flow, bottom-hole temperature (BHT), and thermal conductivity data are used to evaluate the present thermal conditions in the Anadarko basin. Heat flow values decrease from 54-62 mWm{sup {minus}2} in the northern part of the basin to 39-53 mWm{sup {minus}2} in the southern portion of the basin. The variation in the regional conductive heat flow is controlled by basin geometry and by the distribution of radiogenic elements in the basement. The heat flow, thermal conductivity, and lithologic information were combined to construct a 3-D model of the temperature structure of the Anadarko basin. The highest temperatures sedimentary rocks older than Pennsylvanian are offset 35 km north-northwest of the deepest part of the basin. This offset is related to the regional increase in heat flow to the north and to the presence of high thermal conductivity granite wash adjacent to the Wichita Mountains. A plot of the temperature difference between the equilibrium temperatures estimated from the model and the measured BHTs as a function of depth is remarkably similar to the published correction curve for BHTs for wells in Oklahoma. Vitrinite reflectance and apatite fission-track (FT) data are used to estimate the paleogeothermal conditions in the basin. Published vitrinite reflectance values are consistent with a past geographic temperature distribution comparable to the observed distribution with the maximum values offset from the basin axis. FT analysis of sandstones from wells in the southeastern portion of the basin indicates that subsurface temperatures were at least 30C higher than at present, suggest the possibility of substantial erosion in this area.

Kelley, S.A.; Gallardo, J.D.; Carter, L.C.; Blackwell, D.D. (Southern Methodist Univ., Dallas, TX (United States))

1991-03-01

26

NASA/Goddard Thermal Technology Overview 2014  

NASA Technical Reports Server (NTRS)

This presentation summarizes the current plans and efforts at NASA Goddard to develop new thermal control technology for anticipated future missions. It will also address some of the programmatic developments currently underway at NASA, especially with respect to the Technology Development Program at NASA. While funding for basic technology development is still scarce, significant efforts are being made in direct support of flight programs. New technology development continues to be driven by the needs of future missions, and applications of these technologies to current Goddard programs will be addressed. Many of these technologies also have broad applicability to DOD, DOE, and commercial programs. Partnerships have been developed with the Air Force, Navy, and various universities to promote technology development. In addition, technology development activities supported by internal research and development (IRAD) program, the Small Business Innovative Research (SBIR) program, and the NASA Engineering and Safety Center (NESC), are reviewed in this presentation. Specific technologies addressed include; two-phase systems applications and issues on NASA missions, latest developments of electro-hydrodynamically pumped systems, development of high electrical conductivity coatings, and various other research activities. New Technology program underway at NASA, although funding is limited center dot NASA/GSFC's primary mission of science satellite development is healthy and vibrant, although new missions are scarce - now have people on overhead working new missions and proposals center dot Future mission applications promise to be thermally challenging center dot Direct technology funding is still very restricted - Projects are the best source for direct application of technology - SBIR thermal subtopic resurrected in FY 14 - Limited Technology development underway via IRAD, NESC, other sources - Administrator pushing to revive technology and educational programs at NASA - new HQ directorate established

Butler, Daniel; Swanson, Theodore D.

2014-01-01

27

JPL Advanced Thermal Control Technology Roadmap - 2008  

NASA Technical Reports Server (NTRS)

This slide presentation reviews the status of thermal control technology at JPL and NASA.It shows the active spacecraft that are in vairous positions in the solar syatem, and beyond the solar system and the future missions that are under development. It then describes the challenges that the past missions posed with the thermal control systems. The various solutions that were implemented duirng the decades prior to 1990 are outlined. A review of hte thermal challenges of the future misions is also included. The exploration plan for Mars is then reviewed. The thermal challenges of the Mars Rovers are then outlined. Also the challenges of systems that would be able to be used in to explore Venus, and Titan are described. The future space telescope missions will also need thermal control technological advances. Included is a review of the thermal requirements for manned missions to the Moon. Both Active and passive technologies that have been used and will be used are reviewed. Those that are described are Mechanically Pumped Fluid Loops (MPFL), Loop Heat Pipes, an M3 Passive Cooler, Heat Siwtch for Space and Mars surface applications, phase change material (PCM) technology, a Gas Gap Actuateor using ZrNiH(x), the Planck Sorption Cooler (PCS), vapor compression -- Hybrid two phase loops, advanced pumps for two phase cooling loops, and heat pumps that are lightweight and energy efficient.

Birur, Gaj

2008-01-01

28

Air Conditioning and Heating Technology--II.  

ERIC Educational Resources Information Center

Twenty-eight chapters and numerous drawings provide information for instructors and students of air conditioning and heating technology. Chapter 1 lists the occupational opportunities in the field. Chapter 2 covers the background or development of the industry of air conditioning and heating technology. Chapter 3 includes some of the principle…

Gattone, Felix

29

Marketing solar thermal technologies: strategies in Europe, experience in Greece  

Microsoft Academic Search

Solar thermal technologies (STTs) are mature in many EU Member States. However, in some EU regions solar applications, and especially the innovative ones (such as solar heating\\/cooling, solar drying, solar-powered desalination), remain at an early stage. The degree of development of each market does not depend on climate conditions (e.g., insolation) or on different technological developments. The major strengths, weaknesses,

Theocharis D Tsoutsos

2002-01-01

30

Literature review on thermal comfort in transient conditions  

Microsoft Academic Search

The conventional theory of thermal comfort in conditions characteristic for dwellings and offices (for example, that of Fanger) assumes steady-state conditions. Yet thermal conditions in buildings are seldom steady, due to the interaction between building structure, climate, occupancy, and HVAC system. This article reviews work on thermal comfort specifically undertaken to examine what variations in indoor temperatures may be acceptable.

J. L. M. Hensen

1990-01-01

31

Thermal Casimir effect with soft boundary conditions.  

PubMed

We consider the thermal Casimir effect in systems of parallel plates coupled to a massless free field theory via quadratic interaction terms which suppress (i) the field on the plates and (ii) the gradient of the field in the plane of the plates. These boundary interactions correspond to (i) the presence of an electrolyte in the plates and (ii) a uniform field of dipoles, in the plates, which are polarizable in the plane of the plates. These boundary interactions lead to Robin-type boundary conditions in the case where there is no field outside the two plates. In the appropriate limit, in both cases Dirichlet boundary conditions are obtained but we show that in case (i) the Dirichlet limit breaks down at short interplate distances and in (ii) it breaks down at large distances. The behavior of the two plate system is also seen to be highly dependent on whether the system is open or closed. In addition we analyze the Casimir force on a third plate placed between two outer plates. The force acting on the central plate is shown to be highly sensitive to whether or not the fluctuating scalar field is present in the region exterior to the two confining plates. PMID:19257002

Dean, David S

2009-01-01

32

Thermal performance of cold storage in thermal battery for air conditioning  

Microsoft Academic Search

This article studies, experimentally and theoretically, the thermal performance of cold storage in thermal battery for air conditioning. Thermal battery utilizes the superior heat transfer characteristics of heat pipe and eliminates drawbacks found in the conventional thermal storage tank. Experimental investigations are first conducted to study the cold storage thermal performance in two experimental systems: the ratio of distance between

Jen-Jie Chieh; Shu-Ju Lin; Sih-Li Chen

2004-01-01

33

NASA's nuclear thermal propulsion technology project  

NASA Technical Reports Server (NTRS)

The nonnuclear subsystem technologies required for incorporating nuclear thermal propulsion (NTP) into space-exploration missions are discussed. Of particular interest to planned missions are such technologies as materials, instrumentation and controls, turbomachinery, CFD modeling, nozzle extension designs and models, and analyses of exhaust plumes. NASA studies are described and/or proposed for refractory metals and alloys, robotic NTP controls, and turbopump materials candidates. Alternative nozzle concepts such as aerospikes and truncated plugs are proposed, and numerical simulations are set forth for studying heavy molecules and the backstreaming of highly reactive free-radical hydrogen in the exhaust plume. The critical technologies described in the paper are central to the development of NTP, and NTP has the potential to facilitate a range of space exploration activities.

Peecook, Keith M.; Stone, James R.

1992-01-01

34

Control of thermal conditions during crystal growth by inverse modeling  

NASA Astrophysics Data System (ADS)

A numerical modeling algorithm is developed which is able to calculate the powers of an arbitrary number of heaters in a crystal growth configuration in order to obtain a prescribed temperature distribution in a growing crystal. Such a mathematical procedure is called inverse modeling. The algorithm is implemented in our software system CrysVUN++ for global thermal simulation of crystal growth processes. The efficiency of this new strategy of inverse modeling is demonstrated by applying it to an industrial vertical gradient freeze (VGF) process for the growth of GaAs crystals with 3? diameter. As a result we obtain optimized growth conditions which will be discussed in comparison to the state of the art of VGF technology.

Kurz, M.; Müller, G.

2000-01-01

35

Integrated Vehicle Thermal Management for Advanced Vehicle Propulsion Technologies  

SciTech Connect

A critical element to the success of new propulsion technologies that enable reductions in fuel use is the integration of component thermal management technologies within a viable vehicle package. Vehicle operation requires vehicle thermal management systems capable of balancing the needs of multiple vehicle systems that may require heat for operation, require cooling to reject heat, or require operation within specified temperature ranges. As vehicle propulsion transitions away from a single form of vehicle propulsion based solely on conventional internal combustion engines (ICEs) toward a wider array of choices including more electrically dominant systems such as plug-in hybrid electric vehicles (PHEVs), new challenges arise associated with vehicle thermal management. As the number of components that require active thermal management increase, so do the costs in terms of dollars, weight, and size. Integrated vehicle thermal management is one pathway to address the cost, weight, and size challenges. The integration of the power electronics and electric machine (PEEM) thermal management with other existing vehicle systems is one path for reducing the cost of electric drive systems. This work demonstrates techniques for evaluating and quantifying the integrated transient and continuous heat loads of combined systems incorporating electric drive systems that operate primarily under transient duty cycles, but the approach can be extended to include additional steady-state duty cycles typical for designing vehicle thermal management systems of conventional vehicles. The work compares opportunities to create an integrated low temperature coolant loop combining the power electronics and electric machine with the air conditioning system in contrast to a high temperature system integrated with the ICE cooling system.

Bennion, K.; Thornton, M.

2010-04-01

36

Behavior of Materials Under Conditions of Thermal Stress  

NASA Technical Reports Server (NTRS)

A review is presented of available information on the behavior of brittle and ductile materials under conditions of thermal stress and thermal shock. For brittle materials, a simple formula relating physical properties to thermal-shock resistance is derived and used to determine the relative significance of two indices currently in use for rating materials. For ductile materials, thermal-shock resistance depends upon the complex interrelation among several metallurgical variables which seriously affect strength and ductility. These variables are briefly discussed and illustrated from literature sources. The importance of simulating operating conditions in tests for rating materials is especially to be emphasized because of the importance of testing conditions in metallurgy. A number of practical methods that have been used to minimize the deleterious effects of thermal stress and thermal shock are outlined.

Manson, S S

1954-01-01

37

APPLICATION OF THERMAL DESORPTION TECHNOLOGIES TO HAZARDOUS WASTE SITES  

EPA Science Inventory

Thermal desorption is a separation process frequently used to remediate many Superfund sites. Thermal desorption technologies are recommended and used because of (1) the wide range of organic contaminants effectively treated, (2) availability and mobility of commercial systems, ...

38

Optimal working conditions for thermoelectric generators with realistic thermal coupling  

E-print Network

We study how maximum output power can be obtained from a thermoelectric generator(TEG) with nonideal heat exchangers. We demonstrate with an analytic approach based on a force-flux formalism that the sole improvement of the intrinsic characteristics of thermoelectric modules including the enhancement of the figure of merit is of limited interest: the constraints imposed by the working conditions of the TEG must be considered on the same footing. Introducing an effective thermal conductance we derive the conditions which permit maximization of both efficiency and power production of the TEG dissipatively coupled to heat reservoirs. Thermal impedance matching must be accounted for as well as electrical impedance matching in order to maximize the output power. Our calculations also show that the thermal impedance does not only depend on the thermal conductivity at zero electrical current: it also depends on the TEG figure of merit. Our analysis thus yields both electrical and thermal conditions permitting optima...

Apertet, Y; Glavatskaya, O; Goupil, C; Lecoeur, P

2011-01-01

39

Thermal comfort in air-conditioned learning environment  

Microsoft Academic Search

This paper appraises the thermal comfort condition of in air conditioned learning environment of the new learning campus in Universiti Teknologi MARA, Puncak Alam. The physical measurement and survey questionnaires have been thoroughly measured among the occupants (235 respondents) in four air conditioned classrooms along with four lecture theatres. The result shows relative humidity and air velocity are within the

Siti Rohana Mohd Yatim; Meor Ahmad Mustaqim Meor Mohd Zain; Fairus Muhamad Darus; Zitty Sarah Ismail

2011-01-01

40

Mathematical modeling of critical conditions in the thermal explosion  

E-print Network

Mathematical modeling of critical conditions in the thermal explosion problem G. N. Gorelov and V. A. Sobolev1 Samara State University, Russia Abstract The paper is devoted to the thermal explosion of critical regimes thought of as regimes sep- arating the regions of explosive and nonexplosive ways

Schellekens, Michel P.

41

Influence of contact conditions on thermal responses of the hand  

E-print Network

The objective of the research conducted for this thesis was to evaluate the influence of contact conditions on the thermal responses of the finger pad and their perceptual effects. A series of experiments investigated the ...

Galie, Jessica Anne

2009-01-01

42

Solar thermal technology report, FY 1981. Volume 1: Executive summary  

NASA Astrophysics Data System (ADS)

The activities of the Department of Energy's Solar Thermal Technology Program are discussed. Highlights of technical activities and brief descriptions of each technology are given. Solar thermal conversion concepts are discussed in detail, particularily concentrating collectors and salt-gradient solar ponds.

1982-06-01

43

Solar thermal technology report, FY 1981. Volume 1: Executive summary  

NASA Technical Reports Server (NTRS)

The activities of the Department of Energy's Solar Thermal Technology Program are discussed. Highlights of technical activities and brief descriptions of each technology are given. Solar thermal conversion concepts are discussed in detail, particularily concentrating collectors and salt-gradient solar ponds.

1982-01-01

44

Concepts of learning and experience in developing solar thermal technologies  

Microsoft Academic Search

This study presents a picture of development of solar thermal technology, using the learning and experience curve concepts. The cost estimates for solar thermal energy technologies are made assuming a fixed production process, characterized by standard capacity factors, overhead, and labor costs. The learning curve is suggested as a generalization of the costs of potential solar energy system. The concept

F Krawiec

1983-01-01

45

Current Technology for Thermal Protection Systems  

NASA Technical Reports Server (NTRS)

Interest in thermal protection systems for high-speed vehicles is increasing because of the stringent requirements of such new projects as the Space Exploration Initiative, the National Aero-Space Plane, and the High-Speed Civil Transport, as well as the needs for improved capabilities in existing thermal protection systems in the Space Shuttle and in turbojet engines. This selection of 13 papers from NASA and industry summarizes the history and operational experience of thermal protection systems utilized in the national space program to date, and also covers recent development efforts in thermal insulation, refractory materials and coatings, actively cooled structures, and two-phase thermal control systems.

Scotti, Stephen J. (compiler)

1992-01-01

46

Saline ice thickness retrieval under diurnal thermal cycling conditions  

Microsoft Academic Search

An inverse scattering algorithm is presented that reconstructs ice growth under thermal cycling conditions by using time-series active microwave measurements. The algorithm uses a direct scattering model consisting of a physically based electromagnetic model that accounts for thermal and electromagnetic properties of ice and combined volume and surface scattering effects as well as a one-dimensional (1D) thermodynamic model of saline

Shih-En Shih; Kung-Hau Ding; Jin Au Kong; S. V. Nghiem; A. K. Jordan

1998-01-01

47

Thermal human biometeorological conditions and subjective thermal sensation in pedestrian streets in Chengdu, China  

NASA Astrophysics Data System (ADS)

The outdoor thermal environment of a public space is highly relevant to the thermal perception of individuals, thereby affecting the use of space. This study aims to connect thermal human biometeorological conditions and subjective thermal sensation in hot and humid regions and to find its influence on street use. We performed a thermal comfort survey at three locations in a pedestrian precinct of Chengdu, China. Meteorological measurements and questionnaire surveys were used to assess the thermal sensation of respondents. The number of people visiting the streets was counted. Meanwhile, mean radiant temperature (T mrt) and the physiological equivalent temperature (PET) index were used to evaluate the thermal environment. Analytical results reveal that weather and street design drive the trend of diurnal micrometeorological conditions of the street. With the same geometry and orientation, a street with no trees had wider ranges of meteorological parameters and a longer period of discomfort. The neutral temperature in Chengdu (24.4 °C PET) is similar to that in Taiwan, demonstrating substantial human tolerance to hot conditions in hot and humid regions. Visitors' thermal sensation votes showed the strongest positive relationships with air temperature. Overall comfort level was strongly related to every corresponding meteorological parameter, indicating the complexity of people's comfort in outdoor environments. In major alleys with multiple functions, the number of people in the street decreased as thermal indices increased; T mrt and PET had significant negative correlations with the number of people. This study aids in understanding pedestrian street use in hot and humid regions.

Zeng, YuLang; Dong, Liang

2014-08-01

48

Damage Accumulation and Failure of Plasma-Sprayed Thermal Barrier Coatings under Thermal Gradient Cyclic Conditions  

NASA Technical Reports Server (NTRS)

Thermal barrier coatings will be more aggressively designed to protect gas turbine engine hot-section components in order to meet future engine higher fuel efficiency and lower emission goals. A fundamental understanding of the sintering and thermal cycling induced delamination of thermal barrier coating systems under engine-like heat flux conditions will potentially help to improve the coating temperature capability. In this study, a test approach is established to emphasize the real-time monitoring and assessment of the coating thermal conductivity, which can initially increase under the steady-state high temperature thermal gradient test due to coating sintering, and later decrease under the thermal gradient cyclic test due to coating cracking and delamination. Thermal conductivity prediction models have been established for a ZrO2-(7- 8wt%)Y2O3 model coating system in terms of heat flux, time, and testing temperatures. The coating delamination accumulation is then assessed based on the observed thermal conductivity response under the combined steady-state and cyclic thermal gradient tests. The coating thermal gradient cycling associated delaminations and failure mechanisms under simulated engine heat-flux conditions will be discussed in conjunction with the coating sintering and fracture testing results.

Zhu, Dongming; Choi, Sung R.; Ghosn, Louis J.; Miller, rober A.

2005-01-01

49

Current technology for thermal protection systems  

SciTech Connect

Interest in thermal protection systems for high-speed vehicles is increasing because of the stringent requirements of such new projects as the Space Exploration Initiative, the National Aero-Space Plane, and the High-Speed Civil Transport, as well as the needs for improved capabilities in existing thermal protection systems in the Space Shuttle and in turbojet engines. This selection of 13 papers from NASA and industry summarizes the history and operational experience of thermal protection systems utilized in the national space program to date, and also covers recent development efforts in thermal insulation, refractory materials and coatings, actively cooled structures, and two-phase thermal control systems. Separate abstracts were prepared for papers of this report.

Scotti, S.J.

1992-10-01

50

ALTERNATIVE TECHNOLOGIES FOR REFRIGERATION AND AIR-CONDITIONING APPLICATIONS  

EPA Science Inventory

The report gives results of an assessment of refrigeration technologies that are alternatives to vapor compression refrigeration for use in five application categories: domestic air conditioning, commercial air conditioning, mobile air conditioning, domestic refrigeration, and co...

51

Demonstration of Passive Fuel Cell Thermal Management Technology  

NASA Technical Reports Server (NTRS)

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. The passive thermal management system relies on heat conduction within highly thermally conductive cooling plates to move the heat from the central portion of the cell stack out to the edges of the fuel cell stack. Using the passive approach eliminates the need for a coolant pump and other cooling loop components within the fuel cell system which reduces mass and improves overall system reliability. Previous development demonstrated the performance of suitable highly thermally conductive cooling plates and integrated heat exchanger technology to collect the heat from the cooling plates (Ref. 1). The next step in the development of this passive thermal approach was the demonstration of the control of the heat removal process and the demonstration of the passive thermal control technology in actual fuel cell stacks. Tests were run with a simulated fuel cell stack passive thermal management system outfitted with passive cooling plates, an integrated heat exchanger and two types of cooling flow control valves. The tests were run to demonstrate the controllability of the passive thermal control approach. Finally, successful demonstrations of passive thermal control technology were conducted with fuel cell stacks from two fuel cell stack vendors.

Burke, Kenneth A.; Jakupca, Ian; Colozza, Anthony; Wynne, Robert; Miller, Michael; Meyer, Al; Smith, William

2012-01-01

52

Overview of NASA's Thermal Control Technology Development Project  

NASA Technical Reports Server (NTRS)

NASA?s Constellation Program included the Orion, Altair, and Lunar Surface Systems project offices. The first two elements, Orion and Altair, were planned to be manned space vehicles while the third element was much broader and included several sub-elements including Rovers and a Lunar Habitat. The planned missions involving these systems and vehicles included several risks and design challenges. Due to the unique thermal operating environment, many of these risks and challenges were associated with the vehicles? thermal control system. NASA?s Exploration Technology Development Program (ETDP) consisted of several technology development projects. The project chartered with mitigating the aforementioned thermal risks and design challenges was the Thermal Control System Development for Exploration Project. These risks and design challenges were being addressed through a rigorous technology development process that was planned to culminate with an integrated thermal control system test. Although these Constellation elements have been cancelled or significantly changed, the thermal technology development process is being continued within a new program entitled Enabling Technology Development and Demonstration (ETDD). The current paper summarizes the development efforts being performed by the technology development project. The development efforts involve heat acquisition and heat rejection hardware including radiators, heat exchangers, and evaporators. The project has also been developing advanced phase change material heat sinks and performing a material compatibility assessment for a promising thermal control system working fluid. The to-date progress and lessons-learned from these development efforts will be discussed throughout the paper.

Stephan, Ryan A.

2010-01-01

53

Light cone condition for a thermalized QED vacuum  

Microsoft Academic Search

Within the QED effective action approach, we study the propagation of low-frequency light at finite temperature. Starting from a general effective Lagrangian for slowly varying fields whose structure is solely dictated by Lorentz covariance and gauge invariance, we derive the light cone condition for light propagating in a thermalized QED vacuum. As an application, we calculate the velocity shifts, i.e.,

Holger Gies; Auf der Morgenstelle

1999-01-01

54

Estimating Thermal Inertia with a Maximum Entropy Boundary Condition  

NASA Astrophysics Data System (ADS)

Thermal inertia, P [Jm-2s-1/2K-1], is a physical property the land surface which determines resistance to temperature change under seasonal or diurnal heating. It is a function of volumetric heat capacity, c [Jm-3K-1], and thermal conductivity, k [Wm-1K-1] of the soil near the surface: P=?ck. Thermal inertia of soil varies with moisture content due the difference between thermal properties of water and air, and a number of studies have demonstrated that it is feasible to estimate soil moisture given thermal inertia (e.g. Lu et al, 2009, Murray and Verhoef, 2007). We take the common approach to estimating thermal inertia using measurements of surface temperature by modeling the Earth's surface as a 1-dimensional homogeneous diffusive half-space. In this case, surface temperature is a function of the ground heat flux (G) boundary condition and thermal inertia and a daily value of P was estimated by matching measured and modeled diurnal surface temperature fluctuations. The difficulty is in measuring G; we demonstrate that the new maximum entropy production (MEP) method for partitioning net radiation into surface energy fluxes (Wang and Bras, 2011) provides a suitable boundary condition for estimating P. Adding the diffusion representation of heat transfer in the soil reduces the number of free parameters in the MEP model from two to one, and we provided a sensitivity analysis which suggests that, for the purpose of estimating P, it is preferable to parameterize the coupled MEP-diffusion model by the ratio of thermal inertia of the soil to the effective thermal inertia of convective heat transfer to the atmosphere. We used this technique to estimate thermal inertia at two semiarid, non-vegetated locations in the Walnut Gulch Experimental Watershed in southeast AZ, USA and compared these estimates to estimates of P made using the Xue and Cracknell (1995) solution for a linearized ground heat flux boundary condition, and we found that the MEP-diffusion model produced superior thermal inertia estimates. The MEP-diffusion estimates also agreed well with P estimates made using a boundary condition measured with buried flux plates. We further demonstrated the new method using diurnal surface temperature fluctuations estimated from day/night MODIS image pairs and, excluding instances where the soil was extremely dry, found a strong relationship between estimated thermal inertia and measured 5 cm soil moisture. Lu, S., Ju, Z.Q., Ren, T.S. & Horton, R. (2009). A general approach to estimate soil water content from thermal inertia. Agricultural and Forest Meteorology, 149, 1693-1698. Murray, T. & Verhoef, A. (2007). Moving towards a more mechanistic approach in the determination of soil heat flux from remote measurements - I. A universal approach to calculate thermal inertia. Agricultural and Forest Meteorology, 147, 80-87. Wang, J.F. & Bras, R.L. (2011). A model of evapotranspiration based on the theory of maximum entropy production. Water Resources Research, 47. Xue, Y. & Cracknell, A.P. (1995). Advanced thermal inertia modeling. International Journal of Remote Sensing, 16, 431-446.

Nearing, G.; Moran, M. S.; Scott, R.; Ponce-Campos, G.

2012-04-01

55

Automated rapid thermal imaging systems technology  

E-print Network

A major source of energy savings occurs on the thermal envelop of buildings, which amounts to approximately 10% of annual energy usage in the United States. To pursue these savings, energy auditors use closed loop energy ...

Phan, Long N., 1976-

2012-01-01

56

Current Technology for Thermal Protection Systems  

Microsoft Academic Search

Interest in thermal protection systems for high-speed vehicles is increasing because of the stringent requirements of such new projects as the Space Exploration Initiative, the National Aero-Space Plane, and the High-Speed Civil Transport, as well as the needs for improved capabilities in existing thermal protection systems in the Space Shuttle and in turbojet engines. This selection of 13 papers from

Stephen J. Scotti

1992-01-01

57

TREATMENT OF HAZARDOUS PETROLEUM CONTAMINATED SOILS BY THERMAL DESORPTION TECHNOLOGIES  

EPA Science Inventory

Spills, leaks, and accidental discharges of petroleum products have contaminated soil at thousands of sites in the United States. ne remedial action technique for treating petroleum contaminated soil is the use of thermal desorption technologies. his paper describes key elements ...

58

APPLICATION OF THERMAL DESORPTION TECHNOLOGIES TO HAZARDOUS WASTE SITES  

EPA Science Inventory

Thermal desorption is a separation process frequently used to remediate many Superfund sites. hermal desorption technologies are recommended and used because of (1) the wide range of organic contaminants effectively treated, (2) availability and mobility of commercial systems, an...

59

Solar thermal technology evaluation, fiscal year 1982. Volume 2: Technical  

NASA Technical Reports Server (NTRS)

The technology base of solar thermal energy is investigated. The materials, components, subsystems, and processes capable of meeting specific energy cost targets are emphasized, as are system efficiency and reliability.

1983-01-01

60

Porous materials for thermal management under extreme conditions.  

PubMed

A brief analysis is presented of how heat transfer takes place in porous materials of various types. The emphasis is on materials able to withstand extremes of temperature, gas pressure, irradiation, etc. i.e. metals and ceramics, rather than polymers. A primary aim is commonly to maximize either the thermal resistance (i.e. provide insulation) or the rate of thermal equilibration between the material and a fluid passing through it (i.e. to facilitate heat exchange). The main structural characteristics concern porosity (void content), anisotropy, pore connectivity and scale. The effect of scale is complex, since the permeability decreases as the structure is refined, but the interfacial area for fluid-solid heat exchange is, thereby, raised. The durability of the pore structure may also be an issue, with a possible disadvantage of finer scale structures being poor microstructural stability under service conditions. Finally, good mechanical properties may be required, since the development of thermal gradients, high fluid fluxes, etc. can generate substantial levels of stress. There are, thus, some complex interplays between service conditions, pore architecture/scale, fluid permeation characteristics, convective heat flow, thermal conduction and radiative heat transfer. Such interplays are illustrated with reference to three examples: (i) a thermal barrier coating in a gas turbine engine; (ii) a Space Shuttle tile; and (iii) a Stirling engine heat exchanger. Highly porous, permeable materials are often made by bonding fibres together into a network structure and much of the analysis presented here is oriented towards such materials. PMID:18272456

Clyne, T W; Golosnoy, I O; Tan, J C; Markaki, A E

2006-01-15

61

Thermal Cyclic Behavior of Thermal and Environmental Barrier Coatings Investigated Under High-Heat-Flux Conditions  

NASA Technical Reports Server (NTRS)

Environmental barrier coatings (EBC's) have been developed to protect silicon-carbide- (SiC) based ceramic components in gas turbine engines from high-temperature environmental attack. With continuously increasing demands for significantly higher engine operating temperature, future EBC systems must be designed for both thermal and environmental protection of the engine components in combustion gases. In particular, the thermal barrier functions of EBC's become a necessity for reducing the engine-component thermal loads and chemical reaction rates, thus maintaining the required mechanical properties and durability of these components. Advances in the development of thermal and environmental barrier coatings (TBC's and EBC's, respectively) will directly impact the successful use of ceramic components in advanced engines. To develop high-performance coating systems, researchers must establish advanced test approaches. In this study, a laser high-heat-flux technique was employed to investigate the thermal cyclic behavior of TBC's and EBC's on SiC-reinforced SiC ceramic matrix composite substrates (SiC/SiC) under high thermal gradient and thermal cycling conditions. Because the laser heat flux test approach can monitor the coating's real-time thermal conductivity variations at high temperature, the coating thermal insulation performance, sintering, and delamination can all be obtained during thermal cycling tests. Plasma-sprayed yttria-stabilized zirconia (ZrO2-8 wt% Y2O3) thermal barrier and barium strontium aluminosilicate-based environmental barrier coatings (BSAS/BSAS+mullite/Si) on SiC/SiC ceramic matrix composites were investigated in this study. These coatings were laser tested in air under thermal gradients (the surface and interface temperatures were approximately 1482 and 1300 C, respectively). Some coating specimens were also subject to alternating furnace cycling (in a 90-percent water vapor environment at 1300 C) and laser thermal gradient cycling tests (in air), to investigate the water vapor effect. All cyclic tests were conducted using a 60-min hot-time temperature.

Zhu, Dongming; Lee, Kang N.; Miller, Robert A.

2002-01-01

62

Thermal and Mechanical Microspacecraft Technologies for X-2000 Future Deliveries  

NASA Technical Reports Server (NTRS)

Thermal and mechanical technologies are an important part of the X-2000 Future Delivery (X-2000 FD) microspacecraft. A wide range of future space missions are expected to utilize the technologies and the architecture developed by the X-2000 FD. These technologies, besides being small in physical size, make the tiny spacecraft robust and flexible. The X2000 FD architecture is designed to be highly reliable and suitable for a wide range of missions such as planetary landers/orbiters/flybys, earth orbiters, cometary flybys/landers/sample returns, etc. One of the key ideas used in the development of these technologies and architecture is that several functions be in included in each of the thermal and mechanical elements. One of the thermal architecture being explored for the X-2000 FD microspacecraft is integrated thermal energy management of the complete spacecraft using a fluid loop. The robustness and the simplicity of the loop and the flexibility with which it can be integrated in the spacecraft have made it attractive for applications to X-2000 FD. Some of the thermal technologies to be developed as a part of this architecture are passive and active cooling loops, electrically variable emittance surfaces, miniature thermal switches, and specific high density electronic cooling technologies. In the mechanical area, multifunction architecture for the structural elements will be developed. The multifunction aspect is expected to substantially reduce the mass and volume of the spacecraft. Some of the technologies that will be developed are composite material panels incorporating electronics, cabling, and thermal elements in them. The paper to be presented at the 1999 conference, will describe the progress made so far in the microspacecraft thermal and mechanical technologies and approaches for the X2000 Future Deliveries microspacecraft.

Birur, Gaj; Bruno, Robin

1999-01-01

63

Solar thermal powered desalination: membrane versus distillation technologies  

Microsoft Academic Search

Multiple Effect Distillation (MED) is generally considered to be the desalination technology most suited to integration with concentrating solar thermal collectors on a medium to large scale. However the cost and energy requirement of Reverse Osmosis (RO) have fallen significantly in recent years, so that solar thermal powered RO deserves consideration. We compare commercial desalination processes on the basis of

G. Burgess; K. Lovegrove

64

The Effects of Nonuniform Thermal Boundary Condition on Thermal Stress Calculation of Water-Cooled W/Cu Divertors  

NASA Astrophysics Data System (ADS)

The thermal boundary condition has very important effects on the accuracy of thermal stress calculation of a water-cooled W/Cu divertor. In this paper, phase-change heat transfer was simulated based on the Euler homogeneous phase model, and local differences of liquid physical properties were considered under one-sided high heating conditions. The steady-state temperature field and thermal stress field under nonuniform thermal boundary conditions were obtained through numerical calculation. By comparison with the case of traditional uniform thermal boundary conditions, the results show that the distribution of thermal stress under nonuniform thermal boundary conditions exhibits the same trend as that under uniform thermal boundary conditions, but is larger in value. The maximum difference of maximum von Mises stress is up to 42% under the highest heating conditions. These results provide a valuable reference for the thermal stress calculation of water-cooled W/Cu divertors.

Han, Le; Chang, Haiping; Zhang, Jingyang; Liu, Nan; Xu, Tiejun

2014-10-01

65

Thermal Performance Testing of Glass Microspheres under Cryogenic Vacuum Conditions  

NASA Astrophysics Data System (ADS)

A key element of space launch vehicles and systems is thermal insulation for cryogenic tanks and piping. Glass microspheres, or glass bubbles, represent an alternative insulation material for a number of applications. Composite materials and engineered thermal insulation systems are also being developed based on the use of glass bubbles as the main constituent material. Commonly used materials, such as spray-on foam insulation, or SOFI, for vehicle tanks and perlite powder for ground storage tanks, are targeted for replacement with the new-technology systems that use glass bubbles. Complete thermal characterization of the glass bubbles is the first step toward producing the engineering solutions required for the energy-efficient, low-maintenance cryogenic systems of the future. Thermal performance testing of the glass microsphere material was successfully completed at the Cryogenics Test Laboratory of NASA Kennedy Space Center. The test measurements were made at the full temperature difference (typical boundary temperatures of 78 kelvin [K] and 293 K) and included the full cold-vacuum pressure range. The results are reported in apparent thermal conductivity (k-value) and mean heat flux.

Fesmire, J. E.; Augustynowicz, S. D.

2004-06-01

66

A Study on Zoning Regulations' Impact on Thermal Comfort Conditions in Non-conditioned Apartment Buildings in Dhaka City  

E-print Network

on thermal comfort conditions, namely indoor temperature and air velocity. The simulation results were compared to see which zoning schemes provided the most favorable thermal comfort conditions. This research found one of the in-between schemes (60...

Islam, Saiful

2012-02-14

67

Thermal momentum distribution from path integrals with shifted boundary conditions.  

PubMed

For a thermal field theory formulated in the grand canonical ensemble, the distribution of the total momentum is an observable characterizing the thermal state. We show that its cumulants are related to thermodynamic potentials. In a relativistic system, for instance, the thermal variance of the total momentum is a direct measure of the enthalpy. We relate the generating function of the cumulants to the ratio of (a) a partition function expressed as a Matsubara path integral with shifted boundary conditions in the compact direction and (b) the ordinary partition function. In this form the generating function is well suited for Monte Carlo evaluation, and the cumulants can be extracted straightforwardly. We test the method in the SU(3) Yang-Mills theory and obtain the entropy density at three different temperatures. PMID:21517372

Giusti, Leonardo; Meyer, Harvey B

2011-04-01

68

Thermal photon $v_3$ at LHC from fluctuating initial conditions  

E-print Network

We calculate the triangular flow parameter $v_3$ of thermal photons for 0--40\\% central collisions of Pb nuclei at LHC using an event-by-event hydrodynamic model with fluctuating initial conditions. Thermal photon $v_3$ with respect to the the participant plane angle is found to be positive and significant compared to the elliptic flow parameter $v_2$ of thermal photons. In addition, photon $v_3$ as a function of $p_T$ shows similar qualitative nature to photon $v_2$ in the region $1< p_T <6$ GeV/$c$. We argue that while $v_3$ originates from $\\epsilon_3$ deformations of the initial state density distribution, fast buildup of radial flow due to fluctuations is the main driving mechanism for the observed large value.

Rupa Chatterjee; Dinesh K. Srivastava; Thorsten Renk

2014-07-31

69

Experimental investigation of thermal sensors under varying pressure conditions  

NASA Astrophysics Data System (ADS)

The effective thermal conductivity of the granular material covering the top few meters of the surfaces of many extraterrestrial bodies like the Moon, Mars, or asteroids is a key parameter for planetary modeling. The extreme temperatures and pressures dominating many of these bodies are influencing the effective thermal conductivity of the top surface layers as well as the measurement of this parameter. On earth the perhaps most commonly used method for measuring the thermal conductivity of soils and sands in-situ is the line heat source technique. Therefore it is tempting to use it also on planetary surfaces. The already well known line heat method was investigated for application in a low pressure/vacuum environment. Laboratory experiments with five different line heat sensors were performed under varying pressure conditions on various granular analogue materials like glass beads, broken lava or the JSC-1A lunar mare analogue.

Hütter, Erika S.; Kömle, Norbert

2010-05-01

70

Thermal Momentum Distribution from Path Integrals with Shifted Boundary Conditions  

SciTech Connect

For a thermal field theory formulated in the grand canonical ensemble, the distribution of the total momentum is an observable characterizing the thermal state. We show that its cumulants are related to thermodynamic potentials. In a relativistic system, for instance, the thermal variance of the total momentum is a direct measure of the enthalpy. We relate the generating function of the cumulants to the ratio of (a) a partition function expressed as a Matsubara path integral with shifted boundary conditions in the compact direction and (b) the ordinary partition function. In this form the generating function is well suited for Monte Carlo evaluation, and the cumulants can be extracted straightforwardly. We test the method in the SU(3) Yang-Mills theory and obtain the entropy density at three different temperatures.

Giusti, Leonardo [Physics Department, CERN, CH-1211 Geneva 23 (Switzerland); Dipartimento di Fisica, Universita di Milano Bicocca, Piazza della Scienza 3, I-20126 Milano (Italy); Meyer, Harvey B. [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet Mainz, D-55099 Mainz (Germany)

2011-04-01

71

COMPARISON OF INNOVATIVE TECHNOLOGY FOR THERMAL DESTRUCTION OF HAZARDOUS WASTE  

EPA Science Inventory

This paper briefly summaries and compares six technologies which are considered to be innovative to the thermal destruction of hazardous wastes. The six technologies are: Fluidized Bed, Molten Salt, High Temperature Fluid Wall, Plasma Arc, Wet Air Oxidation and Supercritical Wate...

72

Thermal coefficients of technology assimilation by natural systems  

NASA Technical Reports Server (NTRS)

Estimates of thermal coefficients of the rates of technology assimilation processes was made. Consideration of such processes as vegetation and soil recovery and pollution assimilation indicates that these processes proceed ten to several hundred times more slowly in earth's cold regions than in temperate regions. It was suggested that these differential assimilation rates are important data in planning for technological expansion in Arctic regions.

Mueller, R. F.

1971-01-01

73

High-Temperature Adhesives for Thermally Stable Aero-Assist Technologies  

NASA Technical Reports Server (NTRS)

Aero-assist technologies are used to control the velocity of exploration vehicles (EVs) when entering Earth or other planetary atmospheres. Since entry of EVs in planetary atmospheres results in significant heating, thermally stable aero-assist technologies are required to avoid the high heating rates while maintaining low mass. Polymer adhesives are used in aero-assist structures because of the need for high flexibility and good bonding between layers of polymer films or fabrics. However, current polymer adhesives cannot withstand temperatures above 400 C. This innovation utilizes nanotechnology capabilities to address this need, leading to the development of high-temperature adhesives that exhibit high thermal conductivity in addition to increased thermal decomposition temperature. Enhanced thermal conductivity will help to dissipate heat quickly and effectively to avoid temperature rising to harmful levels. This, together with increased thermal decomposition temperature, will enable the adhesives to sustain transient high-temperature conditions.

Eberts, Kenneth; Ou, Runqing

2013-01-01

74

Hypothetical accident conditions thermal analysis of the 5320 package  

SciTech Connect

An axisymmetric model of the 5320 package was created to perform hypothetical accident conditions (HAC) thermal calculations. The analyses assume the 5320 package contains 359 grams of plutonium-238 (203 Watts) in the form of an oxide powder at a minimum density of 2.4 g/cc or at a maximum density of 11.2 g/cc. The solution from a non-solar 100 F ambient steady-state analysis was used as the initial conditions for the fire transient. A 30 minute 1,475 F fire transient followed by cooling via natural convection and thermal radiation to a 100 F non-solar environment was analyzed to determine peak component temperatures and vessel pressures. The 5320 package was considered to be horizontally suspended within the fire during the entire transient.

Hensel, S.J.; Gromada, R.J.

1995-12-31

75

Thermal and catalytic cracking of polyethylene under mild conditions  

Microsoft Academic Search

Thermal and catalytic cracking of both high and low-density polyethylene (HDPE and LDPE, respectively) under mild conditions have been investigated in order to study the properties of the solid waxy product so obtained. The catalysts employed were n-HZSM-5 and HY zeolites, amorphous silica–alumina, activated carbon, Pd charcoal powder and mesoporous aluminosilicate materials (MCM-41), with and without impregnated Pd. The best

R van Grieken; D. P Serrano; J Aguado; R Garc??a; C Rojo

2001-01-01

76

Advancements in thermal spallation drilling technology  

SciTech Connect

Thermal spallation of hard rocks has been used commercially for many years to cut granite in quarries and to produce blasting holes in taconite mines. It is potentially an economic process for creating cavities in hard rocks that are difficult to drill or mine by conventional methods. These cavities might have application for storage of liquids and gases and of energy in several forms. They may also be used as high-pressure, naturally heated retorts for certain chemical processes. This report describes the spallation process, including the fluid dynamics and heat transfer from flame jets to the rock and subsequent rock failure. Our model of the spallation process predicts with good accuracy the surface temperatures and heat-transfer rates required to maintain desired drilling rates. Field tests, including site selection, equipment, field operations, and accomplishments, are also described in detail. 31 refs., 13 figs., 1 tab.

Williams, R.E.; Dey, T.; Rauenzahn, R.; Kranz, R.; Tester, J.; Potter, R.; Murphy, H.

1988-09-01

77

Lightweight Nonmetallic Thermal Protection Materials Technology  

NASA Technical Reports Server (NTRS)

To fulfill President George W. Bush's "Vision for Space Exploration" (2004) - successful human and robotic missions to and from other solar system bodies in order to explore their atmospheres and surfaces - the National Aeronautics and Space Administration (NASA) must reduce the trip time, cost, and vehicle weight so that the payload and scientific experiments' capabilities can be maximized. The new project described in this paper will generate thermal protection system (TPS) product that will enable greater fidelity in mission/vehicle design trade studies, support risk reduction for material selections, assist in the optimization of vehicle weights, and provide materials and processes templates for use in the development of human-rated TPS qualification and certification plans.

Valentine, Peter G.; Lawrence, Timothy W.; Gubert, Michael K.; Milos, Frank S.; Levine, Stanley R.; Ohlhorst, Craig W.; Koenig, John R.

2005-01-01

78

Ceramic technology for solar thermal receivers  

NASA Technical Reports Server (NTRS)

The high-temperature capability, resistance to corrosive environments and non-strategic nature of ceramics have prompted applications in the solar thermal field whose advantages over metallic devices of comparable performance may begin to be assessed. It is shown by a survey of point-focusing receiver designs employing a variety of ceramic compositions and fabrication methods that the state-of-the-art in structural ceramics is not sufficiently advanced to fully realize the promised benefits of higher temperature capabilities at lower cost than metallic alternatives. The ceramics considered include alumina, berylia, magnesia, stabilized zirconia, fused silica, silicon nitride, silicon carbide, mullite and cordierite, processed by such methods as isostatic pressing, dry pressing, slip casting, extrusion, calendaring and injection molding.

Kudirka, A. A.; Smoak, R. H.

1981-01-01

79

Thermal modeling and management in ultrathin chip stack technology  

Microsoft Academic Search

This paper presents a thermal modeling for power management of a new three-dimensional (3-D) thinned dies stacking process. Besides the high concentration of power dissipating sources, which is the direct consequence of the very interesting integration efficiency increase, this new ultra-compact packaging technology can suffer of the poor thermal conductivity (about 700 times smaller than silicon one) of the benzocyclobutene

Stéphane Pinel; Antoine Marty; Josiane Tasselli; Jean-Pierre Bailbe; Eric Beyne; Rita Van Hoof; Santiago Marco; Joan Ramon Morante; Olivier Vendier; Marc Huan

2002-01-01

80

Thermal and electrical conductivity of iron at Earth's core conditions.  

PubMed

The Earth acts as a gigantic heat engine driven by the decay of radiogenic isotopes and slow cooling, which gives rise to plate tectonics, volcanoes and mountain building. Another key product is the geomagnetic field, generated in the liquid iron core by a dynamo running on heat released by cooling and freezing (as the solid inner core grows), and on chemical convection (due to light elements expelled from the liquid on freezing). The power supplied to the geodynamo, measured by the heat flux across the core-mantle boundary (CMB), places constraints on Earth's evolution. Estimates of CMB heat flux depend on properties of iron mixtures under the extreme pressure and temperature conditions in the core, most critically on the thermal and electrical conductivities. These quantities remain poorly known because of inherent experimental and theoretical difficulties. Here we use density functional theory to compute these conductivities in liquid iron mixtures at core conditions from first principles--unlike previous estimates, which relied on extrapolations. The mixtures of iron, oxygen, sulphur and silicon are taken from earlier work and fit the seismologically determined core density and inner-core boundary density jump. We find both conductivities to be two to three times higher than estimates in current use. The changes are so large that core thermal histories and power requirements need to be reassessed. New estimates indicate that the adiabatic heat flux is 15 to 16 terawatts at the CMB, higher than present estimates of CMB heat flux based on mantle convection; the top of the core must be thermally stratified and any convection in the upper core must be driven by chemical convection against the adverse thermal buoyancy or lateral variations in CMB heat flow. Power for the geodynamo is greatly restricted, and future models of mantle evolution will need to incorporate a high CMB heat flux and explain the recent formation of the inner core. PMID:22495307

Pozzo, Monica; Davies, Chris; Gubbins, David; Alfè, Dario

2012-05-17

81

Thermal batteries: A technology review and future directions  

SciTech Connect

Thermally activated (``thermal``) batteries have been used for ordnance applications (e.g., proximity fuzes) since World War II and, subsequent to that, in nuclear weapons. This technology was developed by the Germans as a power source for their V2 rockets. It was obtained by the Allies by interrogation of captured German scientists after the war. The technology developed rapidly from the initial primitive systems used by the Germans to one based on Ca/CaCrO{sub 4}. This system was used very successfully into the late 1970s, when it was replaced by the Li-alloy/FeS{sub 2} electrochemical system. This paper describes the predominant electrochemical couples that have been used in thermal batteries over the years. Major emphasis is placed on the chemistry and electrochemistry of the Ca/CaCrO{sub 4} and Li-alloy/FeS{sub 2} systems. The reason for this is to give the reader a better appreciation for the advances in thermal-battery technology for which these two systems are directly responsible. Improvements to date in the current Li-alloy/FeS{sub 2} and related systems are discussed and areas for possible future research and development involving anodes, cathodes, electrolytes, and insulations are outlined. New areas where thermal-battery technology has potential applications are also examined.

Guidotti, R.A.

1995-07-01

82

Current Issues in Human Spacecraft Thermal Control Technology  

NASA Technical Reports Server (NTRS)

Efficient thermal management of Earth-orbiting human spacecraft, lunar transit spacecraft and landers, as well as a lunar habitat will require advanced thermal technology. These future spacecraft will require more sophisticated thermal control systems that can dissipate or reject greater heat loads at higher input heat fluxes while using fewer of the limited spacecraft mass, volume and power resources. The thermal control designs also must accommodate the harsh environments associated with these missions including dust and high sink temperatures. The lunar environment presents several challenges to the design and operation of active thermal control systems. During the Apollo program, landings were located and timed to occur at lunar twilight, resulting in a benign thermal environment. The long duration polar lunar bases that are foreseen in 15 years will see extremely cold thermal environments. Long sojourns remote from low-Earth orbit will require lightweight, but robust and reliable systems. Innovative thermal management components and systems are needed to accomplish the rejection of heat from lunar bases. Advances are required in the general areas of radiators, thermal control loops and equipment. Radiators on the Moon's poles must operate and survive in very cold environments. Also, the dusty environment of an active lunar base may require dust mitigation and removal techniques to maintain radiator performance over the long term.

Ungar, Eugene K.

2008-01-01

83

Cyclic Failure Mechanisms of Thermal and Environmental Barrier Coating Systems Under Thermal Gradient Test Conditions  

NASA Technical Reports Server (NTRS)

Plasma-sprayed ZrO2-8wt%Y2O3 and mullite+BSAS/Si multilayer thermal and environmental barrier coating (TBC-EBC) systems on SiC/SiC ceramic matrix composite (CMC) substrates were thermally cyclic tested under high thermal gradients using a laser high-heat-flux rig in conjunction with furnace exposure in water-vapor environments. Coating sintering and interface damage were assessed by monitoring the real-time thermal conductivity changes during the laser heat-flux tests and by examining the microstructural changes after exposure. Sintering kinetics of the coating systems were also independently characterized using a dilatometer. It was found that the coating failure involved both the time-temperature dependent sintering and the cycle frequency dependent cyclic fatigue processes. The water vapor environments not only facilitated the initial coating conductivity increases due to enhanced sintering and interface reaction, but also promoted later conductivity reductions due to the accelerated coating cracking and delamination. The failure mechanisms of the coating systems are also discussed based on the cyclic test results and are correlated to the sintering and thermal stress behavior under the thermal gradient test conditions.

Zhu, Dongming; Lee, Kang N.; Miller, Robert A.

2002-01-01

84

Low-thrust chemical propulsion system propellant expulsion and thermal conditioning study  

NASA Technical Reports Server (NTRS)

Thermal conditioning systems for satisfying engine net positive suction pressure (NPSP) requirements, and propellant expulsion systems for achieving propellant dump during a return-to-launch site (RTLS) abort were studied for LH2/LO2 and LCH4/LO2 upper stage propellant combinations. A state-of-the-art thermal conditioning system employing helium injection beneath the liquid surface shows the lowest weight penalty for LO2 and LCH4. A technology system incorporating a thermal subcooler (heat exchanger) for engine NPSP results in the lowest weight penalty for the LH2 tank. A preliminary design of two state-of-the-art and two new technology systems indicates a weight penalty difference too small to warrant development of a LH2 thermal subcooler. Analysis results showed that the LH2/LO2 propellant expulsion system is optimized for maximum dump line diameters, whereas the LCH4/LO2 system is optimized for minimum dump line diameter (LCH4) and maximum dump line diameter (LO2). The primary uncertainty is the accurate determination of two-phase flow rates through the dump system; experimentation is not recommended because this uncertainty is not considered significant.

Merino, F.; Wakabayashi, I.; Pleasant, R. L.; Hill, M.

1982-01-01

85

Thermal Conductivity and Elastic Modulus Evolution of Thermal Barrier Coatings under High Heat Flux Conditions  

NASA Technical Reports Server (NTRS)

Laser high heat flux test approaches have been established to obtain critical properties of ceramic thermal barrier coatings (TBCs) under near-realistic temperature and thermal gradients that may he encountered in advanced engine systems. Thermal conductivity change kinetics of a thin ceramic coating were continuously monitored in real time at various test temperatures. A significant thermal conductivity increase was observed during the laser simulated engine heat flux tests. For a 0.25 mm thick ZrO2-8%Y2O3 coating system, the overall thermal conductivity increased from the initial value of 1.0 W/m-K to 1. 15 W/m-K, 1. 19 W/m-K and 1.5 W/m-K after 30 hour testing at surface temperatures of 990C, 1100C, and 1320C. respectively. Hardness and modulus gradients across a 1.5 mm thick TBC system were also determined as a function of laser testing time using the laser sintering/creep and micro-indentation techniques. The coating Knoop hardness values increased from the initial hardness value of 4 GPa to 5 GPa near the ceramic/bond coat interface, and to 7.5 GPa at the ceramic coating surface after 120 hour testing. The ceramic surface modulus increased from an initial value of about 70 GPa to a final value of 125 GPa. The increase in thermal conductivity and the evolution of significant hardness and modulus gradients in the TBC systems are attributed to sintering-induced micro-porosity gradients under the laser-imposed high thermal gradient conditions. The test techniques provide a viable means for obtaining coating data for use in design, development, stress modeling, and life prediction for various thermal barrier coating applications.

Zhu, Dongming; Miller, Robert A.

1999-01-01

86

Overall Thermal Performance of Flexible Piping Under Simulated Bending Conditions  

NASA Technical Reports Server (NTRS)

Flexible, vacuum-insulated transfer lines for low-temperature applications have higher thermal losses than comparable rigid lines. Typical flexible piping construction uses corrugated tubes, inner and outer, with a multilayer insulation (MLI) system in the annular space. Experiments on vacuum insulation systems in a flexible geometry were conducted at the Cryogenics Test Laboratory of NASA Kennedy Space Center. The effects of bending were simulated by causing the inner tube to be eccentric with the outer tube. The effects of spacers were simulated in a controlled way by inserting spacer tubes for the length of the cylindrical test articles. Two material systems, standard MLI and a layered composite insulation (LCI), were tested under the full range of vacuum levels using a liquid nitrogen boiloff calorimeter to determine the apparent thermal conductivity (k-value). The results indicate that the flexible piping under simulated bending conditions significantly degrades the thermal performance of the insulation system. These data are compared to standard MLI for both straight and flexible piping configurations. The definition of an overall k-value for actual field installations (k(sub oafi)) is described for use in design and analysis of cryogenic piping systems.

Fesmire, James E.; Augustynowicz, S. D.; Demko, J. A.; Thompson, Karen (Technical Monitor)

2001-01-01

87

Heavy oil reservoirs recoverable by thermal technology  

NASA Astrophysics Data System (ADS)

Data are presented on reservoirs that contain heavy oil in the 8 to 25(0) API gravity range, contain at least ten million barrels of oil currently in place, and are noncarbonate in lithology. The reservoirs within these constraints were analyzed in light of applicable recovery technology, either steam drive or in situ combustion, and then ranked hierarchically as candidate reservoirs. An extensive basis for heavy oil development is provided, however, it is recommended that data on carbonate reservoirs, and tar sands be compiled. It was discovered that operators, and industrial and government analysts will lump heavy oil reservoirs as poor producers, however, it was found that upon detailed analysis, a large number, so categorized, were producing very well. A big problem in producing heavy oil is that of regulation; specifically, it was found that the regulatory constraints are so fluid and changing that one cannot settle on a favorable recovery and production plan with enough confidence in the regulatory requirements to commit capital to the project.

Kujawa, P.

1981-02-01

88

Application of Nanofiber Technology to Nonwoven Thermal Insulation  

Microsoft Academic Search

Nanofiber technology (fiber diameter less than 1 micrometer) is under development for future Army lightweight protective clothing systems. Nanofiber applications for ballistic and chemical\\/biological protection are being actively investigated, but the thermal properties of nanofibers and their potential protection against cold environments are relatively unknown. Previous studies have shown that radiative heat transfer in fibrous battings is minimized at fiber

Phillip W. Gibson; Calvin Lee; Frank Ko; Darrell Reneker

89

Treatment and recycling of incinerated ash using thermal plasma technology  

Microsoft Academic Search

To treat incinerated ash is an important issue in Taiwan. Incinerated ashes contain a considerable amount of hazardous materials such as dioxins and heavy metals. If these hazardous materials are improperly treated or disposed of, they shall cause detrimental secondary contamination. Thermal plasma vitrification is a robust technology to treat and recycle the ash residues. Under the high temperature plasma

T. W Cheng; J. P Chu; C. C Tzeng; Y. S Chen

2002-01-01

90

Advances in NASA's Nuclear Thermal Propulsion Technology project  

NASA Technical Reports Server (NTRS)

The status of the Nuclear Thermal Propulsion (NTP) project for space exploration and the future plans for NTP technology are discussed. Current activities in the framework of the NTP project deal with nonnuclear material tests; instrumentation, controls, and health management; turbopumps; nozzles and nozzle extension; and an exhaust plume.

Peecook, Keith M.; Stone, James R.

1993-01-01

91

Proceedings of the Distributed Receiver Solar Thermal Technology Conference  

NASA Astrophysics Data System (ADS)

The Distributed Receiver Solar Thermal Technology Conference was held on April 24 and 25, 1985 at the Classic Hotel, Albuquerque, New Mexico. The meeting was sponsored by the United States Department of Energy and Sandia National Laboratories. Topics covered during the conference included a status summary of the Sandia Distributed Receiver Development project, perspectives on distributed electric technology and distributed receiver energy collection and conversion, technologies, systems analyses and applications experiments. The proceedings contain summaries (abstracts plus principal visual aids) of the presentations made at the conference.

Muire, J. F.

1985-04-01

92

Eye Contact Conditioning in Autistic Children Using Virtual Reality Technology  

E-print Network

Eye Contact Conditioning in Autistic Children Using Virtual Reality Technology Xi Wang1 , Nicholas notable indicators of Autism Spectrum Disorder is a deficit in eye contact [1][2]. In early development

Gnawali, Omprakash

93

Heating, Ventilating, and Air Conditioning. Energy Technology Series.  

ERIC Educational Resources Information Center

This course in heating, ventilating, and air conditioning is one of 16 courses in the Energy Technology Series developed for an Energy Conservation-and-Use Technology curriculum. Intended for use in two-year postsecondary technical institutions to prepare technicians for employment, the courses are also useful in industry for updating employees in…

Center for Occupational Research and Development, Inc., Waco, TX.

94

Experiments and models of active and thermal imaging under bad weather conditions  

NASA Astrophysics Data System (ADS)

Thermal imaging cameras are widely used in military contexts for their night vision capabilities and their observation range; there are based on passive infrared sensors (e.g. MWIR or LWIR range). Under bad weather conditions or when the target is partially hidden (e.g. foliage, military camouflage) they are more and more complemented by active imaging systems, a key technology to perform target identification at long range. The 2D flash imaging technique is based on a high powered pulsed laser source that illuminates the entire scene and a fast gated camera as the imaging system. Both technologies are well experienced under clear meteorological conditions; models including atmospheric effects such as turbulence are able to predict accurately their performances. However, under bad weather conditions such as rain, haze or snow, these models are not relevant. This paper introduces new models to predict performances under bad weather conditions for both active and infrared imaging systems. We point out their effects on controlled physical parameters (extinction, transmission, spatial resolution, thermal background, speckle, turbulence). Then we develop physical models to describe their intrinsic characteristics and their impact on the imaging system performances. Finally, we approximate these models to have a "first order" model easy to deploy for industrial applications. This theoretical work will be validated on real active and infrared data.

Bernard, Erwan; Riviere, Nicolas; Renaudat, Mathieu; Guiset, Pierrick; Pealat, Michel; Zenou, Emmanuel

2013-10-01

95

Peptide Formation Mechanism on Montmorillonite Under Thermal Conditions  

NASA Astrophysics Data System (ADS)

The oligomerization of amino acids is an essential process in the chemical evolution of proteins, which are precursors to life on Earth. Although some researchers have observed peptide formation on clay mineral surfaces, the mechanism of peptide bond formation on the clay mineral surface has not been clarified. In this study, the thermal behavior of glycine (Gly) adsorbed on montmorillonite was observed during heating experiments conducted at 150 °C for 336 h under dry, wet, and dry-wet conditions to clarify the mechanism. Approximately 13.9 % of the Gly monomers became peptides on montmorillonite under dry conditions, with diketopiperazine (cyclic dimer) being the main product. On the other hand, peptides were not synthesized in the absence of montmorillonite. Results of IR analysis showed that the Gly monomer was mainly adsorbed via hydrogen bonding between the positively charged amino groups and negatively charged surface sites (i.e., Lewis base sites) on the montmorillonite surface, indicating that the Lewis base site acts as a catalyst for peptide formation. In contrast, peptides were not detected on montmorillonite heated under wet conditions, since excess water shifted the equilibrium towards hydrolysis of the peptides. The presence of water is likely to control thermodynamic peptide production, and clay minerals, especially those with electrophilic defect sites, seem to act as a kinetic catalyst for the peptide formation reaction.

Fuchida, Shigeshi; Masuda, Harue; Shinoda, Keiji

2014-02-01

96

Limiting factors to advancing thermal battery technology for naval applications  

NASA Astrophysics Data System (ADS)

Thermal batteries are primary reserve electrochemical power sources using molten salt electrolyte which experience little effective aging while in storage or dormant deployment. Thermal batteries are primarily used in military applications, and are currently used in a wide variety of Navy devices such as missiles, torpedoes, decays, and training targets, usually as power supplies in guidance, propulsion, and Safe/Arm applications. Technology developments have increased the available energy and power density ratings by an order of magnitude in the last ten years. Present thermal batteries, using lithium anodes and metal sulfide cathodes, are capable of performing applications where only less rugged and more expensive silver oxide/zinc or silver/magnesium chloride seawater batteries could serve previously. Additionally, these batteries are capable of supplanting lithium/thionyl chloride reserve batteries in a variety of specifically optimized designs. Increases in thermal battery energy and power density capabilities are not projected to continue with the current available technology. Several battery designs are now at the edge of feasibility and safety. Since future naval systems are likely to require continued growth of battery energy and power densities, there must be significant advances in battery technology. Specifically, anode alloy composition and new cathode materials must be investigated to allow for safe development and deployment of these high power, higher energy density batteries.

Davis, Patrick B.; Winchester, Clinton S.

1991-10-01

97

A cost analysis of photovoltaic technologies under Jamaica'S climatic conditions  

Microsoft Academic Search

With the spiraling cost of imported fossil fuels and high values of insolation, the Caribbean region hopes that photovoltaic (PV) technologies will provide a more cost effective and secure energy solution. PV performance parameters are given under Standard Test Conditions (STC). Since STC is never realised under normal operational conditions (NOC) within Jamaica's climate, it is essential that we investigate

Darlene A. Field; Claude McNamarah

2010-01-01

98

Thermal Plasma Technology: Where Do We Stand and Where Are We Going?  

Microsoft Academic Search

In this overview, an attempt is made to assess the present and future research and development in thermal plasma processing of materials restricted to (1) thermal plasma coating technologies, (2) thermal plasma synthesis of fine powders, (3) thermal plasma waste destruction, and (4) thermal plasma spheroidization and densification. Since thermal plasma processing is, in general, governed by a large number

E. Pfender

1999-01-01

99

INTEGRATION OF DISTRIBUTED ENERGY RESOURCES AND THERMALLY-ACTIVATED TECHNOLOGIES  

Microsoft Academic Search

A new CHP Integration Test Facility has been commissioned at the Oak Ridge National Laboratory (ORNL) for the testing of distributed energy resources (DER) combined with thermally-activated technologies for combined cooling, heating, and power (CHP). Presently, it has been set up to test a 30-kW microturbine with both direct and indirect-fired desiccant dehumidification systems and a 10-ton indirect-fired single-effect absorption

D. Tom Rizy; Abdi Zaltash; Solomon Labinov; Andrei Petrov; Phil Fairchild

100

Development of Passive Fuel Cell Thermal Management Technology  

NASA Technical Reports Server (NTRS)

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. The passive thermal management system relies on heat conduction within the cooling plate to move the heat from the central portion of the cell stack out to the edges of the fuel cell stack rather than using a pumped loop cooling system to convectively remove the heat. Using the passive approach eliminates the need for a coolant pump and other cooling loop components which reduces fuel cell system mass and improves overall system reliability. Previous analysis had identified that low density, ultra-high thermal conductivity materials would be needed for the cooling plates in order to achieve the desired reductions in mass and the highly uniform thermal heat sink for each cell within a fuel cell stack. A pyrolytic graphite material was identified and fabricated into a thin plate using different methods. Also a development project with Thermacore, Inc. resulted in a planar heat pipe. Thermal conductivity tests were done using these materials. The results indicated that lightweight passive fuel cell cooling is feasible.

Burke, Kenneth A.; Jakupca, Ian; Colozza, Anthony

2011-01-01

101

Non-thermal plasma: An emerging technology for VOCs control  

SciTech Connect

The effectiveness of applying non-thermal plasma for destroying VOCs from gas streams is experimentally investigated in this study. p-Xylene, designated as air toxics in the 1990 US Clean Air Act Amendment, is selected as target pollutants due to its wide use in industrial processes. Exposure to fairly low levels of p-xylene (a few ppm) can cause irritation to nose, skin and eyes. In addition, it is odor-causing VOCs which has received much public concern especially in Taiwan due to its high population density. Various technologies have been developed for removing VOCs, e.g., condensation, activated carbon adsorption, thermal decomposition, heterogeneous catalysis and biofiltration. However, there are some limitations with these technologies. Recently, non-thermal plasma technologies have been proposed as an innovative way for VOCs control. Non-thermal plasma can be generated via various methods including dielectric barrier discharge, corona discharge, DC discharge, packed-bed discharge and RF discharge. The sinks of xylene in atmosphere are primarily involved with the reactions with O and OH atoms. Interestingly, O and OH atoms can be effectively generated via nonthermal plasma processes. A laboratory-scale reactor is designed and constructed for evaluating the effectiveness of nonthermal plasma for destroying p-xylene molecules. The nonthermal plasma is generated with dielectric barrier discharge operating at atmospheric pressure. Operating parameters investigated in this study include applied voltage, temperature and composition of the gas stream. Results indicate that as high as 100% p-xylene removal efficiencies can be achieved.

Lee, H.M.; Chang, M.B. [National Central Univ., Chungli (Taiwan, Province of China). Graduate Inst. of Environmental Engineering

1998-12-31

102

Evaluation of thermal comfort conditions in Ourmieh Lake, Iran  

NASA Astrophysics Data System (ADS)

Research in developing countries concerning the relationship of weather and climate conditions with tourism shows a high importance not only because of financial aspects but also an important part of the region's tourism resource base. Monthly mean air temperature, relative humidity, precipitation, vapor pressure, wind velocity, and cloud cover for the period 1985-2005 data collected from four meteorological stations Tabriz, Maragheh, Orumieh, and Khoy were selected. The purpose of this study is to determine the most suitable months for human thermal comfort in Ourmieh Lake, a salt sea in the northwest of Iran. To achieve this, the cooling power and physiologically equivalent temperature (PET) calculated by the RayMan model and the Climate Tourism/Transfer Information Scheme (CTIS) were used. The results based on cooling power indicate that the most favorable period for tourism, sporting, and recreational activities in Ourmieh Lake is between June and October and based on PET between June to September. In addition, the CTIS shows a detailed quantification of the relevant climate-tourism factors.

Farajzadeh, Hassan; Matzarakis, Andreas

2012-02-01

103

On the sensitivity of 4 different CPV module technologies to relevant ambient and operation conditions  

NASA Astrophysics Data System (ADS)

The sensitivity of four different CPV module technologies to most operating conditions relevant to CPV systems has been studied, namely DNI, spectrum, cell and lens temperature and clearness of the sky. In order to isolate the influence of a single operation parameter, the analysis of long-term outdoor monitoring data is required. The effect of lens temperature on cell current has been found to vary greatly between modules due to the different optical architectures studied. Maximum sensitivity is found for silicone-on-glass primary lenses. The VOC thermal coefficient was found to vary between module technologies, probably due to differences in maximum local effective concentration.

Domínguez, César; Besson, Pierre

2014-09-01

104

First responder thermal imaging cameras: establishment of representative performance testing conditions  

NASA Astrophysics Data System (ADS)

Thermal imaging cameras are rapidly becoming integral equipment for first responders for use in structure fires and other emergencies. Currently there are no standardized performance metrics or test methods available to the users and manufacturers of these instruments. The Building and Fire Research Laboratory (BFRL) at the National Institute of Standards and Technology is conducting research to establish test conditions that best represent the environment in which these cameras are used. First responders may use thermal imagers for field operations ranging from fire attack and search/rescue in burning structures, to hot spot detection in overhaul activities, to detecting the location of hazardous materials. In order to develop standardized performance metrics and test methods that capture the harsh environment in which these cameras may be used, information has been collected from the literature, and from full-scale tests that have been conducted at BFRL. Initial experimental work has focused on temperature extremes and the presence of obscuring media such as smoke. In full-scale tests, thermal imagers viewed a target through smoke, dust, and steam, with and without flames in the field of view. The fuels tested were hydrocarbons (methanol, heptane, propylene, toluene), wood, upholstered cushions, and carpeting with padding. Gas temperatures, CO, CO II, and O II volume fraction, emission spectra, and smoke concentrations were measured. Simple thermal bar targets and a heated mannequin fitted in firefighter gear were used as targets. The imagers were placed at three distances from the targets, ranging from 3 m to 12 m.

Amon, Francine; Hamins, Anthony; Rowe, Justin

2006-04-01

105

Evaluation Framework and Analyses for Thermal Energy Storage Integrated with Packaged Air Conditioning  

SciTech Connect

Few third-party guidance documents or tools are available for evaluating thermal energy storage (TES) integrated with packaged air conditioning (AC), as this type of TES is relatively new compared to TES integrated with chillers or hot water systems. To address this gap, researchers at the National Renewable Energy Laboratory conducted a project to improve the ability of potential technology adopters to evaluate TES technologies. Major project outcomes included: development of an evaluation framework to describe key metrics, methodologies, and issues to consider when assessing the performance of TES systems integrated with packaged AC; application of multiple concepts from the evaluation framework to analyze performance data from four demonstration sites; and production of a new simulation capability that enables modeling of TES integrated with packaged AC in EnergyPlus. This report includes the evaluation framework and analysis results from the project.

Kung, F.; Deru, M.; Bonnema, E.

2013-10-01

106

Distributed automatic control of technological processes in conditions of weightlessness  

NASA Technical Reports Server (NTRS)

Some problems associated with the automatic control of liquid metal and plasma systems under conditions of weightlessness are examined, with particular reference to the problem of stability of liquid equilibrium configurations. The theoretical fundamentals of automatic control of processes in electrically conducting continuous media are outlined, and means of using electromagnetic fields for simulating technological processes in a space environment are discussed.

Kukhtenko, A. I.; Merkulov, V. I.; Samoylenko, Y. I.; Ladikov-Royev, Y. P.

1986-01-01

107

Battery condition monitoring (BCM) technologies about lead–acid batteries  

Microsoft Academic Search

A novel battery condition monitoring (BCM) technology for lead–acid batteries has been developed. We have developed a highly reliable SOC monitor that improves the estimated precision of the stored capacity to ±5% for both the flooded type and VRLA. A novel SOC estimation algorithm was also developed. The SOC value was obtained by the weighting combination of the values from

Tetsuro Okoshi; Keizo Yamada; Tokiyoshi Hirasawa; Akihiko Emori

2006-01-01

108

High temperature solar thermal technology: The North Africa Market  

SciTech Connect

High temperature solar thermal (HTST) technology offers an attractive option for both industrialized and non-industrialized countries to generate electricity and industrial process steam. The purpose of this report is to assess the potential market for solar thermal applications in the North African countries of Algeria, Egypt, Morocco and Tunisia. North Africa was selected because of its outstanding solar resource base and the variety of applications to be found there. Diminishing oil and gas resources, coupled with expanding energy needs, opens a large potential market for the US industry. The US high temperature solar trough industry has little competition globally and could build a large market in these areas. The US is already familiar with certain solar markets in North Africa due to the supplying of substantial quantities of US-manufactured flat plate collectors to this region.

Not Available

1990-12-01

109

Poaceae pollen in the air depending on the thermal conditions  

NASA Astrophysics Data System (ADS)

The relationship between the meteorological elements, especially the thermal conditions and the Poaceae pollen appearance in the air, were analysed as a basis to construct a useful model predicting the grass season start. Poaceae pollen concentrations were monitored in 1991-2012 in Kraków using the volumetric method. Cumulative temperature and effective cumulative temperature significantly influenced the season start in this period. The strongest correlation was seen as the sum of mean daily temperature amplitudes from April 1 to April 14, with mean daily temperature >15 °C and effective cumulative temperature >3 °C during that period. The proposed model, based on multiple regression, explained 57 % of variation of the Poaceae season starts in 1991-2010. When cumulative mean daily temperature increased by 10 °C, the season start was accelerated by 1 day. The input of the interaction between these two independent variables into the factor regression model caused the increase in goodness of model fitting. In 2011 the season started 5 days earlier in comparison with the predicted value, while in 2012 the season start was observed 2 days later compared to the predicted day. Depending on the value of mean daily temperature from March 18th to the 31st and the sum of mean daily temperature amplitudes from April 1st to the 14th, the grass pollen seasons were divided into five groups referring to the time of season start occurrence, whereby the early and moderate season starts were the most frequent in the studied period and they were especially related to mean daily temperature in the second half of March.

Myszkowska, Dorota

2014-07-01

110

Thermal energy storage technologies for heating and cooling applications  

NASA Astrophysics Data System (ADS)

Recent results from selected thermal energy storage (TES) research activities in Germany and Sweden are discussed. In addition, several new technologies for heating and cooling of buildings and automobiles were reviewed and found to benefit similar efforts in the United states. Details of a meeting with Didier-Werke AG, a leading German ceramics manufacturer who will provide TES media necessary for the United States to complete field tests of an advanced high temperature latent heat storage material, are presented. Finally, an overview of the December 1990 International Energy Agency (IEA) Executive Committee deliberations on TES is presented.

Tomlinson, John J.

1990-12-01

111

Coated columbium thermal protection systems: An assessment of technological readiness  

NASA Technical Reports Server (NTRS)

Evaluation and development to date show that of the coated columbium alloys FS-85 coated with R512E shows significant promise for a reusable thermal protection system (TPS) as judged by environmental resistance and the retention of mechanical properties and structural integrity of panels upon repeated reentry simulation. Production of the alloy, the coating, and full-sized TPS panels is well within current manufacturing technology. Small defects which arise from impact damage or from local coating breakdown do not appear to have serious immediate consequences in the use environment anticipated for the space shuttle orbiter TPS.

Levine, S. R.; Grisaffe, S. J.

1973-01-01

112

Advanced solar thermal technologies for the 21st century  

NASA Technical Reports Server (NTRS)

The paper considers the present status of solar thermal dynamic space power technologies and projects the various attributes of these systems into the future, to the years 2000 and 2010. By the year 2000, collector weights should decrease from 1.25 kg/sq m (1985 value) to about 1.0 kg/sq m. The specific weight is also expected to decrease from 6.0 kg/kw. By the year 2010, slight improvements in the free piston Stirling energy conversion system are postulated with efficiencies reaching 32 percent. In addition, advanced concentrator concepts should be operational.

Kohout, L. L.; Perez-Davis, M. E.

1986-01-01

113

Gaseous and particulate emissions from thermal power plants operating on different technologies.  

PubMed

This paper presents the assessment of gaseous and particulate emissions from thermal power plants operating on different combustion technologies. Four thermal power plants operating on heavy furnace oil were selected for the study, among which three were based on diesel engine technology, while the fourth plant was based on oil-fired steam turbine technology. The stack emissions were monitored for critical air pollutants carbon monoxide, carbon dioxide, oxides of nitrogen, sulfur dioxide, particulate matter, lead, and mercury. The pollutant emissions were measured at optimum load conditions for a period of 6 months with an interval of 1 month. The results of stack emissions were compared with National Environmental Quality Standards of Pakistan and World Bank guidelines for thermal power plants, and few parameters were found higher than the permissible limits of emissions. It was observed that the emissions carbon monoxide, oxides of nitrogen, and particulate matters from diesel engine-based power plants were comparatively higher than the turbine-based power plants. The emissions of sulfur dioxide were high in all the plants, even the plants with different technologies, which was mainly due to high sulfur contents in fuel. PMID:19533397

Athar, Makshoof; Ali, Mahboob; Khan, Misbahul Ain

2010-07-01

114

Hydraulic fracturing theory for conditions of thermal stress  

Microsoft Academic Search

Thermal stresses associated with a temperature change of only 10°C are on the order of 10 to 100 bars. This illustrates the important influence thermal stresses can impose on the results of rock stress measurements by the hydraulic fracturing method. In order to examine the problem, expressions are derived to describe the stress field produced by non-steady state heat conduction

G. Stephens; B. Voight

1982-01-01

115

Effects of Black Spot Disease on Thermal Tolerances and Condition Factors of Three Cyprinid Fishes  

Microsoft Academic Search

The influence of black spot disease, a metacercarial infestation, on thermal tolerances (critical thermal maximum, CTMax, and critical thermal minimum, CTMin) and fish condition factor (KTL) was examined in three cyprinid fish species: spotfin shiner Notropis spilopterus, bluntnose minnow Pimephales notatus, and striped shiner Notropis chrysocephalus. Metacercarial counts of 2 to 535 per fish had little or no effect on

Christopher T. Hockett; Neal D. Mundahl

1989-01-01

116

Bottom Anti-Reflective Coatings for DUV lithography: Determination of optimum thermal process conditions  

Microsoft Academic Search

This paper investigates the thermal process conditions of the CD11 Bottom Anti-Reflective Coating for DUV lithography using various characterization techniques such as TGA and DSC. The thermal modifications of the material are related to the variations in its functional properties, namely degree of solubility, absorption, thickness and reflectivity. A thermal process window is defined to obtain maximum improvement from this

A. Schiltz; J. F. Terpan; G. Amblard; P. J. Paniez

1997-01-01

117

Evaluation of airborne thermal, magnetic, and electromagnetic characterization technologies  

SciTech Connect

The identification of Buried Structures (IBS) or Aerial Surveillance Project was initiated by the US Department of Energy (DOE) Office of Technology Development to demonstrate airborne methods for locating and identifying buried waste and ordnance at the Idaho National Engineering Laboratory (INEL). Two technologies were demonstrated: (a) a thermal infrared imaging system built by Martin Marietta Missile Systems and (b) a magnetic and electromagnetic (EM) geophysical surveying system operated by EBASCO Environmental. The thermal system detects small differences in ground temperature caused by uneven heating and cooling of the ground by the sun. Waste materials on the ground can be detected when the temperature of the waste is different than the background temperature. The geophysical system uses conventional magnetic and EM sensors. These sensors detect disturbances caused by magnetic or conductive waste and naturally occurring magnetic or conductive features of subsurface soils and rock. Both systems are deployed by helicopter. Data were collected at four INEL sites. Tests at the Naval Ordnance Disposal Area (NODA) were made to evaluate capabilities for detecting ordnance on the ground surface. Tests at the Cold Simulated Waste Demonstration Pit were made to evaluate capabilities for detecting buried waste at a controlled site, where the location and depth of buried materials are known. Tests at the Subsurface Disposal Area and Stationary Low-Power Reactor-1 burial area were made to evaluate capabilities for characterizing hazardous waste at sites that are typical of DOE buried waste sites nationwide.

Josten, N.E.

1992-03-01

118

Mercury emissions control technologies for mixed waste thermal treatment  

SciTech Connect

EPA has identified wet scrubbing at low mercury feedrates, as well as carbon adsorption via carbon injection into the offgas or via flow through fixed carbon beds, as control technologies that can be used to meet the proposed Maximum Achievable Control Technology (MACT) rule limit for mercury emissions from hazardous waste incinerators. DOE is currently funding demonstrations of gold amalgamation that may also control mercury to the desired levels. Performance data from a variety of sources was reviewed to determine ranges of achievable mercury control. Preliminary costs were estimated for using these technologies to control mercury emissions from mixed waste incineration. Mercury emissions control for mixed waste incineration may need to be more efficient than for incineration of other hazardous wastes because of higher mercury concentrations in some mixed waste streams. However, mercury control performance data for wet scrubbing and carbon adsorption is highly variable. More information is needed to demonstrate control efficiencies that are achievable under various design and operating conditions for wet scrubbing, carbon adsorption, and gold amalgamation technologies. Given certain assumptions made in this study, capital costs, operating costs, and lifecycle costs for carbon injection, carbon beds, and gold amalgamation generally vary for different assumed mercury feedrates and for different offgas flowrates. Assuming that these technologies can in fact provide the necessary mercury control performance, each of these technologies may be less costly than the others for certain mercury feedrates and the offgas flowrates.

Chambers, A.; Knecht, M.; Soelberg, N.; Eaton, D. [Lockheed Martin Idaho Technologies Co., Idaho Falls, ID (United States). Idaho National Engineering and Environmental Lab.; Roberts, D.; Broderick, T. [ADA Technologies, Englewood, CO (United States)

1997-12-31

119

Investigation of Thermal Stress Convection in Nonisothermal Gases Under Microgravity Conditions  

NASA Technical Reports Server (NTRS)

Microgravity conditions offer an environment in which convection in a nonisothermal gas could be driven primarily by thermal stress. A direct examination of thermal stress flows would be invaluable in assessing the accuracy of the Burnett terms in the fluid stress tensor. We present a preliminary numerical investigation of the competing effects of thermal stress, thermal creep at the side walls, and buoyancy on gas convection in nonuniformly heated containers under normal and reduced gravity levels. Conditions in which thermal stress convection becomes dominant are identified, and issues regarding the experimental measurement of the flows are discussed.

Mackowski, Daniel W.; Knight, Roy W.

1996-01-01

120

Thermal conductivity and elastic modulus evolution of thermal barrier coatings under high heat flux conditions  

Microsoft Academic Search

Laser high heat flux test approaches have been established to obtain critical properties of ceramic thermal barrier coatings\\u000a (TBCs) under near-realistic temperature and thermal gradients that may be encountered in advanced engine systems. Thermal\\u000a conductivity change kinetics of a thin ceramic coating were continuously monitored in real time at various test temperatures.\\u000a A significant thermal conductivity increase was observed during

Dongming Zhu; Robert A. Miller

2000-01-01

121

Molten-salt thermal energy storage in thermoclines under different environmental boundary conditions  

Microsoft Academic Search

Operation during the charge and discharge cycles of molten-salt thermoclines used for solar thermal energy storage depends strongly on the environmental boundary conditions to which the tanks are exposed. A comprehensive model which accounts for thermal transport in the molten-salt heat transfer fluid and the filler material in the tank is developed for exploring the effects of boundary conditions on

Zhen Yang; Suresh V. Garimella

2010-01-01

122

Carbon monoxide oxidation rates computed for automobile thermal reactor conditions  

NASA Technical Reports Server (NTRS)

Carbon monoxide oxidation rates in thermal reactors for exhaust manifolds are computed by integrating differential equations for system of twenty-nine reversible chemical reactions. Reactors are noncatalytic replacements for conventional exhaust manifolds and are a system for reducing carbon monoxide and hydrocarbons in automobile exhausts.

Brokaw, R. S.; Bittker, D. A.

1972-01-01

123

ABIOTIC DEGRADATION OF TRICHLOROETHYLENE UNDER THERMAL REMEDIATION CONDITIONS  

EPA Science Inventory

The degradation of TCE (C2HCl3) to carbon dioxide (CO2) and chloride (Cl-) has been reported to occur during thermal remediation of subsurface environments. The overall goal of this study was to evaluate abiotic degradation of TCE at el...

124

MOBILE AIR CONDITIONING FUEL CONSUMPTION & THERMAL COMFORT ASSESSMENT PROCEDURE  

Microsoft Academic Search

The paper describes a proposal for method to assess the fuel consumption and the perceived thermal comfort level during Climatic room testing. The procedure has been elaborated in the framework of the EU funded project BCOOL and constitutes one of the project outputs. The BCOOL project is focused to the development of a low cost and high efficiency CO2 Mobile

C. Malvicino; S. Mola; D. Clodic; Centro Ricerche Fiat; Strada Torino

125

Thermal Modeling and Device Noise Properties of Three-Dimensional-SOI Technology  

E-print Network

Thermal test structures and ring oscillators (ROs) are fabricated in 0.18-mum three-dimensional (3-D)-SOI technology. Measurements and electrothermal simulations show that thermal and parasitic effects due to 3-D packaging ...

Chen, Tze Wee

126

Numerical modeling of physical vapor transport under microgravity conditions: Effect of thermal creep and stress  

NASA Technical Reports Server (NTRS)

One of the most promising applications of microgravity (micro-g) environments is the manufacture of exotic and high-quality crystals in closed cylindrical ampoules using physical vapor transport (PVT) processes. The quality enhancements are believed to be due to the absence of buoyant convection in the weightless environment - resulting in diffusion-limited transport of the vapor. In a typical experiment, solid-phase sample material is initially contained at one end of the ampoule. The sample is made to sublime into the vapor phase and deposit onto the opposite end by maintaining the source at an elevated temperature with respect to the deposit. Identification of the physical factors governing both the rates and uniformity of crystal growth, and the optimization of the micro-g technology, will require an accurate modeling of the vapor transport within the ampoule. Previous micro-g modeling efforts have approached the problem from a 'classical' convective/diffusion formulation, in which convection is driven by the action of buoyancy on thermal and solutal density differences. The general conclusion of these works have been that in low gravity environments the effect of buoyancy on vapor transport is negligible, and vapor transport occurs in a diffusion-limited mode. However, it has been recently recognized than in the non-isothermal (and often low total pressure) conditions encountered in ampoules, the commonly-assumed no-slip boundary condition to the differential equations governing fluid motion can be grossly unrepresentative of the actual situation. Specifically, the temperature gradients can give rise to thermal creep flows at the ampoule side walls. In addition, temperature gradients in the vapor itself can, through the action of thermal stress, lead to bulk fluid convection.

Mackowski, Daniel W.; Knight, Roy W.

1993-01-01

127

Task 4 supporting technology. Part 2: Detailed test plan for thermal seals. Thermal seals evaluation, improvement and test. CAN8-1, Reusable Launch Vehicle (RLV), advanced technology demonstrator: X-33. Leading edge and seals thermal protection system technology demonstration  

NASA Technical Reports Server (NTRS)

The objective is to develop the advanced thermal seals to a technology readiness level (TRL) of 6 to support the rapid turnaround time and low maintenance requirements of the X-33 and the future reusable launch vehicle (RLV). This program is divided into three subtasks: (1) orbiter thermal seals operation history review; (2) material, process, and design improvement; and (3) fabrication and evaluation of the advanced thermal seals.

Hogenson, P. A.; Lu, Tina

1995-01-01

128

Task 4 supporting technology. Part 2: Detailed test plan for thermal seals. Thermal seals evaluation, improvement and test. CAN8-1, Reusable Launch Vehicle (RLV), advanced technology demonstrator: X-33. Leading edge and seals thermal protection system technology demonstration  

NASA Astrophysics Data System (ADS)

The objective is to develop the advanced thermal seals to a technology readiness level (TRL) of 6 to support the rapid turnaround time and low maintenance requirements of the X-33 and the future reusable launch vehicle (RLV). This program is divided into three subtasks: (1) orbiter thermal seals operation history review; (2) material, process, and design improvement; and (3) fabrication and evaluation of the advanced thermal seals.

Hogenson, P. A.; Lu, Tina

1995-05-01

129

ANALYSIS OF THERMAL DECOMPOSITION PRODUCTS OF FLUE GAS CONDITIONING AGENTS  

EPA Science Inventory

The report gives results of a study of reactions of several flue gas conditioning agents in a laboratory-scale facility simulating conditions in the flue gas train of a coal-burning power plant. Primary purposes of the study were to characterize the chemical species resulting fro...

130

Determining Adaptability Performance of Artificial Neural Network-Based Thermal Control Logics for Envelope Conditions in Residential Buildings  

E-print Network

This study examines the performance and adaptability of Artificial Neural Network (ANN)-based thermal control strategies for diverse thermal properties of building envelope conditions applied to residential buildings. The thermal performance using...

Moon, Jin Woo; Chang, Jae D.; Kim, Sooyoung

2013-07-18

131

Transition from thermal to athermal friction under cryogenic conditions.  

PubMed

Atomic scale frictional forces encountered as a function of temperature for the contact of a Si3N4 probe tip and the basal plane of MoS2 have been measured with atomic force microcopy over the temperature range 100-500 K. Friction is observed to increase exponentially with decreasing temperature from 500 to 220 K. An Arrhenius analysis of the temperature dependent friction over this range yields an effective activation energy of approximately 0.3 eV for the thermally activated stick-slip motion of the probe tip on this surface. As temperature is reduced further below 220 K, a distinct transition to a largely athermal behavior is detected and is shown to result from the onset of interfacial wear, entailing an alternative energy dissipation pathway. PMID:19518889

Zhao, Xueying; Phillpot, Simon R; Sawyer, W Gregory; Sinnott, Susan B; Perry, Scott S

2009-05-01

132

Thermal storage HVAC system retrofit provides economical air conditioning  

SciTech Connect

This article describes an EMS-controlled HVAC system that meets the ventilation and cooling needs of an 18,000-seat indoor ice hockey arena. The Buffalo Memorial Auditorium (affectionately referred to as the Aud) was built in 1937 under the Works Project Administration of the federal government. Its original configuration included a 12,000-seat arena with an ice skating rink. By the late 1980s, the city was unsuccessfully attempting to attract events and tenants to the auditorium, which lacked air conditioning and other modern amenities. Thus, it was decided to renovate the facility to make it marketable. The first phase of the renovation included installing an air-conditioning system in the arena and repairing the existing building systems that were inoperable because of deferred maintenance. After considering the existing conditions (such as size of the space, intermittent usage, construction restrictions, operating budgets and the limited operations staff), the engineering team designed an innovative HVAC system. The system's features include: a carbon dioxide monitoring device that controls the intake of outside air; an ice storage system that provides chilled water and shifts electrical demand to off-peak hours; and a design that uses the building mass as a heat sink. A new energy management system (EMS) determines building cooling needs based on the type of event, ambient conditions and projected audience size. Then, it selects the most economical method to obtain the desired arena temperature.

Smith, S.F. (Wendel Engineers, P.C., Buffalo, NY (United States))

1993-03-01

133

A Study on the Thermal Fatigue Behavior of Solder Joints Under Power Cycling Conditions  

Microsoft Academic Search

Failure mechanisms exposed by environmental accelerating testing methods such as thermal cycling or thermal shock test, may differ from those at service operating conditions. While the device is heated up or cooled down evenly on its external surface during environmental testing, real operating powered devices experience temperature gradients caused by internal local heating, components' different heat dissipation capability, and ambient

Se Young Yang; Ilho Kim; Soon-Bok Lee

2008-01-01

134

Energy efficient engine, high pressure turbine thermal barrier coating. Support technology report  

NASA Technical Reports Server (NTRS)

This report describes the work performed on a thermal barrier coating support technology task of the Energy Efficient Engine Component Development Program. A thermal barrier coating (TBC) system consisting of a Ni-Cr-Al-Y bond cost layer and ZrO2-Y2O3 ceramic layer was selected from eight candidate coating systems on the basis of laboratory tests. The selection was based on coating microstructure, crystallographic phase composition, tensile bond and bend test results, erosion and impact test results, furnace exposure, thermal cycle, and high velocity dynamic oxidation test results. Procedures were developed for applying the selected TBC to CF6-50, high pressure turbine blades and vanes. Coated HPT components were tested in three kinds of tests. Stage 1 blades were tested in a cascade cyclic test rig, Stage 2 blades were component high cycle fatigue tested to qualify thermal barrier coated blades for engine testing, and Stage 2 blades and Stage 1 and 2 vanes were run in factory engine tests. After completion of the 1000 cycle engine test, the TBC on the blades was in excellent condition over all of the platform and airfoil except at the leading edge above midspan on the suction side of the airfoil. The coating damage appeared to be caused by particle impingement; adjacent blades without TBC also showed evidence of particle impingement.

Duderstadt, E. C.; Agarwal, P.

1983-01-01

135

Mechanical and thermal buckling analysis of rectangular sandwich panels under different edge conditions  

NASA Technical Reports Server (NTRS)

The combined load (mechanical or thermal load) buckling equations were established for orthotropic rectangular sandwich panels under four different edge conditions by using the Rayleigh-Ritz method of minimizing the total potential energy of a structural system. Two-dimensional buckling interaction curves and three-dimensional buckling interaction surfaces were constructed for high-temperature honeycomb-core sandwich panels supported under four different edge conditions. The interaction surfaces provide overall comparison of the panel buckling strengths and the domains of symmetrical and antisymmetrical buckling associated with the different edge conditions. In addition, thermal buckling curves of these sandwich panels are presented. The thermal buckling conditions for the cases with and without thermal moments were found to be identical for the small deformation theory.

Ko, William L.

1994-01-01

136

Energy Comparison Between Conventional and Chilled Water Thermal Storage Air Conditioning Systems  

E-print Network

, encouraged by government subsidies and driven by the rapid and continual expansion in building construction, urban development, and the heavy reliance on Air Conditioning (AC) systems for the cooling of buildings. The Chilled Water Thermal Storage (CWTS...

Sebzali, M.; Hussain, H. J.; Ameer, B.

2010-01-01

137

Thermal Synthesis of Nucleoside H-Phosphonates Under Mild Conditions  

NASA Astrophysics Data System (ADS)

Nucleosides react rapidly with ammonium phosphite ((NH4)2HPO3) at 60 °C to produce good yields of nucleoside-5’-phosphite monoesters within 24 h. Under the same conditions, ammonium phosphate is unreactive, producing low yields of nucleotide only after extended reactions. These results confirm earlier suggestions that nucleoside H-phosphonates and their possible condensation products may have been produced on the primitive earth more easily than nucleotides.

de Graaf, R. M.; Schwartz, Alan W.

2005-02-01

138

IEEE TRANSACTIONS ON CONTROL SYSTEM TECHNOLOGY 1 Online Parameterization of Lumped Thermal  

E-print Network

of the battery temperature is the key to an effective thermal management system and to maintain safety (PHEV) and battery electric vehicles (BEV). Thermal management is a critical issue for onboard lithiumIEEE TRANSACTIONS ON CONTROL SYSTEM TECHNOLOGY 1 Online Parameterization of Lumped Thermal Dynamics

Stefanopoulou, Anna

139

Limiting Factors to Advancing Thermal Battery Technology for Naval Applications.  

National Technical Information Service (NTIS)

Thermal batteries are primary reserve electrochemical power sources using molten salt electrolyte which experience little effective aging while in storage or dormant deployment. Thermal batteries are primarily used in military applications, and are curren...

P. B. Davis, C. S. Winchester

1991-01-01

140

Science and technology of the mechanical thermal dewatering.  

E-print Network

??In the work at hand basic experimental results are presented for the mechanical/thermal dewatering (MTE, German abbreviation for ‘Mechanisch/Thermische Entwässerung’, also used for ‘mechanical/thermal expression’… (more)

Bergins, Christian

2008-01-01

141

Thermal conductivity measurements of glass beads and regolith simulant under vacuum conditions  

NASA Astrophysics Data System (ADS)

Past studies of in-situ and laboratory measurements of lunar regolith thermal conductivity imply that the conductivity would vary with depth due to change of density and self-weighted stress. In this study, we experimentally investigated the effect of the compressional stress on the thermal conductivity of the glass beads and regolith simulant using a new stress controlling system under vacuum conditions. We experimentally confirmed that the thermal conductivity increases with the compressional stress, which indicates that the regolith layer on the airless terrestrial bodies has various thermal conductivities according to the depth and their gravity.

Sakatani, N.; Ogawa, K.; Iijima, Y.; Tsuda, S.; Honda, R.; Tanaka, S.

2013-09-01

142

NASA Office of Aeronautics and Space Technology Summer Workshop. Volume 8: Thermal control panel  

NASA Technical Reports Server (NTRS)

Technology deficiencies in the area of thermal control for future space missions are identified with emphasis on large space structures and cold controlled environments. Thermal control surfaces, heat pipes, and contamination are considered along with cryogenics, insulation, and design techniques. Major directions forecast for thermal control technology development and space experiments are: (1) extend the useful lifetime of cryogenic systems for space, (2) reduce temperature gradients, and (3) improve temperature stability.

1975-01-01

143

NON-THERMAL PLASMA TECHNOLOGY FOR DEGRADATION OF ORGANIC COMPOUNDS IN WASTEWATER CONTROL: A CRITICAL REVIEW  

Microsoft Academic Search

Non-thermal plasma is an emerging technique in environmental pollution control technology, produced by the high-voltage discharge processes and therefore a large amount of high energy electrons and active species are generated. The degradation of difficult-degraded organic pollutions will be greatly enhanced by the active species generated from non-thermal plasma process. However, research on non-thermal plasma technology on organic wastewater cleaning

Hsu-Hui Cheng; Shiao-Shing Chen; Yu-Chi Wu; Din-Lit Ho

144

Status of thermal imaging technology as applied to conservation-update 1  

SciTech Connect

This document updates the 1978 report on the status of thermal imaging technology as applied to energy conservation in buildings. Thermal imaging technology is discussed in terms of airborne surveys, ground survey programs, and application needs such as standards development and lower cost equipment. Information on the various thermal imaging devices was obtained from manufacturer's standard product literature. Listings are provided of infrared projects of the DOE building diagnostics program, of aerial thermographic firms, and of aerial survey programs. (LCL)

Snow, F.J.; Wood, J.T.; Barthle, R.C.

1980-07-01

145

Influence of thermalization on the initial condition for heavy ion collisions  

NASA Astrophysics Data System (ADS)

In this paper, we discuss the important role of the thermalization process in the initial distribution of QGP. We find that the negligible heat conduction inside QGP can be expressed as an effective Fourier law and we further analyse qualitatively the results caused by a thermalized initial condition. Based on this arguments, we construct a simple phenomenological model and work with the hydro code, and then we compare our results with the experimental data and the results of the standard initial model. It is found that, as we have argued, a thermalized initial condition suppresses the value of the elliptic flow.

Zhao, AMeng; Sun, WeiMin; Zong, HongShi

2014-08-01

146

Inverse Thermal Analysis of a Titanium Laser Weld Using Multiple Constraint Conditions  

NASA Astrophysics Data System (ADS)

Inverse thermal analysis of a titanium laser weld using multiple constraint conditions is presented. This analysis employs a methodology that is in terms of numerical-analytical basis functions for inverse thermal analysis of steady-state energy deposition in plate structures. The results of this type of analysis provide parametric representations of weld temperature histories that can be adopted as input data to various types of computational procedures, such as those for prediction of solid-state phase transformations. In addition, these temperature histories can be used to construct parametric-function representations for inverse thermal analysis of welds corresponding to other process parameters or welding processes whose process conditions are within similar regimes. The present study extends an inverse thermal analysis procedure applied in previous studies. This extension provides for the inclusion of constraint conditions associated with both solidification and phase transformation boundaries.

Lambrakos, S. G.; Shabaev, A.; Huang, L.

2014-06-01

147

Research on Thermal Properties in a Phase Change Wallboard Room Based on Air Conditioning Cold Storage  

E-print Network

of Science and Technology Press, 1996. [2] J.Kelly kissock, J Michael Hannig, Thomas I. Whitney et al. Early results from testing phase change wallboard, IEA Annex10? phase change materials and chemical reactions for thermal energy storage first... Acta,1998,317:39? 45. [5] Feldman D,Banu D,Hawes D. Low chain esters of ICEBO2006, Shenzhen, China Envelope Technologies for Building Energy Efficiency Vol.II-2-3 stearic acid as phase change materials for thermal energy storage...

Feng, G.; Li, W.; Chen, X.

2006-01-01

148

Thermal and Mechanical Microspacecraft Technologies for Deep Space Systems Program X2000 Future Deliveries  

NASA Technical Reports Server (NTRS)

Thermal and mechanical technologies are an important part of the Deep Space Systems Technology (DSST) Program X2000 Future Deliveries (FD) microspacecraft. A wide range of future space missions are expected to utilize the technologies and the architecture developed by DSST FD. These technologies, besides being small in physical size, make the tiny spacecraft robust and flexible. The DSST FD architecture is designed to be highly reliable and suitable for a wide range of missions such as planetary landers/orbiters/flybys, earth orbiters, cometary flybys/landers/sample returns, etc. Two of the key ideas used in the development of thermal and mechanical technologies and architectures are: 1) to include several of the thermal and mechanical functions in any given single spacecraft element and 2) the architecture be modular so that it can easily be adapted to any of the future missions. One of the thermal architectures being explored for the DSST FD microspacecraft is the integrated thermal energy management of the complete spacecraft using a fluid loop. The robustness and the simplicity of the loop and the flexibility with which it can be integrated in the spacecraft have made it attractive for applications to DSST FD. Some of the thermal technologies to be developed as a part of this architecture are passive and active cooling loops, electrically variable emittance surfaces, miniature thermal switches, and specific high density electronic cooling technologies. In the mechanical area, multifunction architecture for the structural elements will be developed. The multifunction aspect is expected to substantially reduce the mass and volume of the spacecraft. Some of the technologies that will be developed are composite material panels incorporating electronics, cabling, and thermal elements in them. The paper describes the current state of the technologies and progress to be made in the thermal and mechanical technologies and approaches for the DSST Future Deliveries microspacecraft.

Birur, Gajanana C.; Bruno, Robin J.

1999-01-01

149

INFLUENCE OF THERMAL CHALLENGE ON CONDITIONED FEEDING FORAYS OF JUVENILE RAINBOW TROUT  

EPA Science Inventory

Juvenile rainbow trout (Salmo gairdneri) conditioned to traverse a 2.4-m-long channel to receive a food reward where subjected to in-transit thermal challenges. Conditioning was to a criterion that required 80% of the fish to leave the 'home' area and reach the 'reward' area with...

150

Empirical validation of thermal dynamics in a silicon microthruster: influence of boundary conditions  

Microsoft Academic Search

This paper investigates the influence of boundary conditions on the validation of a dynamic compact thermal model. The applied boundary conditions are used to consider the effect of the non-modelled parts of the microthruster. The values obtained through different optimization processes show the presence of local minima. This effect is overcome through a design of experiments, based on a central

M. Salleras; I. Garcia; J. Palacin; M. Puig; J. Samitier; S. Marco

2004-01-01

151

Performance Testing of Thermal Interface Filler Materials in a Bolted Aluminum Interface Under Thermal/Vacuum Conditions  

NASA Technical Reports Server (NTRS)

A thermal interface material is one of the many tools often used as part of the thermal control scheme for space-based applications. Historically, at Marshall Space Flight Center, CHO-THERM 1671 has primarily been used for applications where an interface material was deemed necessary. However, numerous alternatives have come on the market in recent years. It was decided that a number of these materials should be tested against each other to see if there were better performing alternatives. The tests were done strictly to compare the thermal performance of the materials relative to each other under repeatable conditions and do not take into consideration other design issues, such as off-gassing, electrical conduction, isolation, etc. The purpose of this Technical Memorandum is to detail the materials tested, test apparatus, procedures, and results of these tests. The results show that there are a number of better performing alternatives now available.

Glasgow, S. D.; Kittredge, K. B.

2003-01-01

152

Thermal bioclimatic conditions and patterns of behaviour in an urban park in Göteborg, Sweden  

NASA Astrophysics Data System (ADS)

. People in urban areas frequently use parks for recreation and outdoor activities. Owing to the complexity of the outdoor environment, there have only been a few attempts to understand the effect of the thermal environment on people's use of outdoor spaces. This paper therefore seeks to determine the relationship between the thermal environment, park use and behavioural patterns in an urban area of Sweden. The methods used include structured interviews, unobtrusive observations of the naturally occurring behaviour and simultaneous measurements of thermal comfort variables, i.e., air temperature, air humidity, wind speed and global radiation. The thermal environment is investigated through the mean radiant temperature (Tmrt) and the predicted mean vote (PMV) index. The outcome is compared to the subjective behaviour and thermal sensation of the interviewees. It is found that the thermal environment, access and design are important factors in the use of the park. In order to continue to use the park when the thermal conditions become too cold or too hot for comfort, people improve their comfort conditions by modifying their clothing and by choosing the most supportive thermal opportunities available within the place. The study also shows that psychological aspects such as time of exposure, expectations, experience and perceived control may influence the subjective assessment. Comparison between the thermal sensation of the interviewees and the thermal sensation assessed by the PMV index indicates that steady-state models such as the PMV index may not be appropriate for the assessment of short-term outdoor thermal comfort, mainly because they are unable to analyse transient exposure.

Thorsson, Sofia; Lindqvist, Maria; Lindqvist, Sven

153

Thermal characteristics of the 12-gigahertz, 200-watt output stage tube for the communications technology satellite  

NASA Technical Reports Server (NTRS)

A description of the methods used to measure component temperatures and heat-rejection rates in a simulated space environment on output stage tubes (OST's) developed for the Communications Technology Satellite is presented along with summaries of experimentally determined values. The OST's were operated over the entire anticipated operating drive range, from the dc beam (zero drive) condition to the 6-db overdrive condition. The baseplate temperature was varied from -10 to 58 C with emphasis placed on the testing done at 45 C, the normal anticipated operating temperature. The heat-rejection rate of the OST baseplate ranged from 7.6 W at the dc beam condition to 184.5 W at the 6-db overdrive condition; the heat-rejection rate of the multistage depressed collector (MDC) cover ranged from 192.2 to 155.9 W for the same conditions. The maximum OST temperature measured on the MDC cover was 227 C during a dc beam test. The minimum temperature measured, also on the MDC cover, was -67.5 C at the end of an extended simulated eclipse test period. No effects were observed on the OST thermal characteristics due to vibration testing or temperature-reversal cycle testing.

Curren, A. N.

1978-01-01

154

Limiting factors to advancing thermal battery technology for naval applications  

Microsoft Academic Search

Thermal batteries are primary reserve electrochemical power sources using molten salt electrolyte which experience little effective aging while in storage or dormant deployment. Thermal batteries are primarily used in military applications, and are currently used in a wide variety of Navy devices such as missiles, torpedoes, decays, and training targets, usually as power supplies in guidance, propulsion, and Safe\\/Arm applications.

Patrick B. Davis; Clinton S. Winchester

1991-01-01

155

Thermal storage technologies for solar industrial process heat applications  

NASA Technical Reports Server (NTRS)

The state-of-the-art of thermal storage subsystems for the intermediate and high temperature (100 C to 600 C) solar industrial process heat generation is presented. Primary emphasis is focused on buffering and diurnal storage as well as total energy transport. In addition, advanced thermal storage concepts which appear promising for future solar industrial process heat applications are discussed.

Gordon, L. H.

1979-01-01

156

Mechanically Pumped Fluid Loop (MPFL) Technologies for Thermal Control of Future Mars Rovers  

NASA Technical Reports Server (NTRS)

Mechanically pumped fluid loop has been the basis of thermal control architecture for the last two Mars lander and rover missions and is the key part of the MSL thermal architecture. Several MPFL technologies are being developed for the MSL rover include long-life pumps, thermal control valves, mechanical fittings for use with CFC-11 at elevated temperatures of approx.100 C. Over three years of life tests and chemical compatibility tests on these MPFL components show that MPFL technology is mature for use on MSL. The advances in MPFL technologies for MSL Rover will benefit any future MPFL applications on NASA s Moon, Mars and Beyond Program.

Birur, Gaj; Bhandari, Pradeep; Prina, Mauro; Bame, Dave; Yavrouian, Andre; Plett, Gary

2006-01-01

157

SSTAC/ARTS review of the draft Integrated Technology Plan (ITP). Volume 3: Space power and thermal management  

NASA Technical Reports Server (NTRS)

Viewgraphs of briefings from the SSTAC/ARTS review of the draft integrated technology plan on thermal power and thermal management are presented. Topics covered include: space energy conversion research and technology; space photovoltaic energy conversion; chemical energy conversion and storage; thermal energy conversion; power management; thermal management; space nuclear power; high capacity power; surface power and thermal management; space platforms power and thermal management; and project SELENE.

1991-01-01

158

Theoretical analysis of the conditions required for rendering metallic alloys amorphous during gas-thermal spraying  

Microsoft Academic Search

During gas-thermal spraying, a coating is obtained under the conditions of extremely high rates of cooling (splat cooling) of the molten material that frequently lead to the formation of metastable crystalline and amorphous phases [1-4]. Some of the eutectic alloys are rendered amorphous using virtually any of the available methods of gas-thermal spraying, viz., gas-flame [2], plasma-arc [3], and detonation-gas

V. N. Korzhik

1992-01-01

159

MEASUREMENT AND SIMULATION OF THE THERMAL BEHAVIOR OF A MASSIVE BUILDING WITH PASSIVE SOLAR CONDITIONING  

Microsoft Academic Search

The measured thermal behavior of a massive building that uses passive techniques for indoor air conditioning is presented. The building thermal transient behavior was simulated with SIMEDIF code. The measured mean indoor temperatures fall between 20 and 23.5ºC, while the outdoor temperature is around 15ºC. Because of the symmetry of the building with respect to the north-south plane, the assumption

Silvana Flores Larseni; Alejandro Hernández; Graciela Lesinoii; Nahuel Salvo; Silvana Flores Larsen; Graciela Lesino

160

Technology for Space Station Evolution. Volume 5: Structures and Materials/Thermal Control System  

NASA Technical Reports Server (NTRS)

NASA's Office of Aeronautics and Space Technology (OAST) conducted a workshop on technology for space station evolution on 16-19 Jan. 1990. The purpose of this workshop was to collect and clarify Space Station Freedom technology requirements for evolution and to describe technologies that can potentially fill those requirements. These proceedings are organized into an Executive Summary and Overview and five volumes containing the Technology Discipline Presentations. Volume 5 consists of the technology discipline sections for Structures/Materials and the Thermal Control System. For each technology discipline, there is a level 3 subsystem description, along with papers.

1990-01-01

161

Thermal anomalies of the transmitter experiment package on the communications technology satellite  

NASA Technical Reports Server (NTRS)

The causes of four temporary thermal-control-system malfunctions that gave rise to unexpected temperature excursions in the 12-gigahertz, 200-watt transmitter experiment package (TEP) on the Communications Technology Satellite were investigated. The TEP consists of a nominal 200-watt output stage tube (OST), a supporting power-processing system (PPS), and a variable-conductance heat-pipe system (VCHPS). The VCHPS, which uses three heat pipes to conduct heat from the body of the OST to a radiator fin, was designed to maintain the TEP at safe operating temperatures at all operating conditions. On four occasions during 1977, all near the spring and fall equinoxes, the OST body temperature and related temperatures displayed sudden, rapid, and unexpected rises above normal levels while the TEP was operating at essentially constant, normal conditions. The temperature excursions were terminated without TEP damage by reducing the radio frequency (RF) output power of the OST. Between the anomalies and since the fourth, the thermal control system has apparently functioned as designed. The results indicate the most probable cause of the temperature anomalies is depriming of the arteries in the variable-conductance heat pipes. A mode was identified in which the TEP, as presently configured, may operate with stable temperatures and with minimum change in performance level.

Alexovich, R. E.; Curren, A. N.

1979-01-01

162

Thermal performance of MSFC hot air collectors under natural and simulated conditions  

NASA Technical Reports Server (NTRS)

The procedures used and the results obtained from an evaluation test program conducted to determine the thermal performance and structural characteristics of selected MSFC--designed hot air collectors under both real and simulated environmental conditions are described. Five collectors were tested in the three phased program. A series of outdoor tests were conducted to determine stagnation temperatures on a typical bright day and to determine each collector's ability to withstand these temperatures. Two of the collectors experienced structural deformation sufficient to eliminate them from the remainder of the test program. A series of outdoor tests to evaluate the thermal performance of collector S/N 10 under certain test conditions were performed followed by a series of indoor tests to evaluate the thermal performance of the collector under closely controlled simulated conditions.

Shih, K., Sr.

1977-01-01

163

Overview of non-thermal mixed waste treatment technologies: Treatment of mixed waste (ex situ); Technologies and short descriptions  

SciTech Connect

This compendium contains brief summaries of new and developing non- thermal treatment technologies that are candidates for treating hazardous or mixed (hazardous plus low-level radioactive) wastes. It is written to be all-encompassing, sometimes including concepts that presently constitute little more than informed ``ideas``. It bounds the universe of existing technologies being thought about or considered for application on the treatment of such wastes. This compendium is intended to be the very first step in a winnowing process to identify non-thermal treatment systems that can be fashioned into complete ``cradle-to-grave`` systems for study. The purpose of the subsequent systems paper studies is to investigate the cost and likely performance of such systems treating a representative sample of U.S. Department of Energy (DOE) mixed low level wastes (MLLW). The studies are called Integrated Non-thermal Treatment Systems (INTS) Studies and are being conducted by the Office of Science and Technology (OST) of the Environmental Management (EM) of the US Department of Energy. Similar studies on Integrated Thermal Treatment Systems have recently been published. These are not designed nor intended to be a ``downselection`` of such technologies; rather, they are simply a systems evaluation of the likely costs and performance of various non- thermal technologies that have been arranged into systems to treat sludges, organics, metals, soils, and debris prevalent in MLLW.

NONE

1995-07-01

164

A Transient Thermal Model for Friction Stir Weld. Part II: Effects of Weld Conditions  

NASA Astrophysics Data System (ADS)

In Part II of this series of articles, the transient thermal model, which was introduced in Part I, is used to explore the effects of welding conditions on the heat generation and temperature. FSW of the 6061-T651 aluminum alloy is modeled to demonstrate the model. The following two steps are adopted to study the influence of welding conditions on the heat generation and temperature. First, the thermal model is used to compute the heat generation and temperature for different welding conditions, the calculated results are compared with the reported experimental temperature, and a good agreement is observed. Second, the analytical method is used to explore the approximate functions describing the effect of welding conditions on the heat generation and temperature. Based on the computed results, we discuss the relationship between the welding conditions, heat generation, temperature, and friction coefficient, and propose a relationship map between them for the first time at the end.

Zhang, X. X.; Xiao, B. L.; Ma, Z. Y.

2011-10-01

165

Evaluation of thermal comfort conditions in a classroom equipped with radiant cooling systems and subjected to uniform convective environment  

Microsoft Academic Search

The aim of this work is to evaluate numerically the human thermal response that 24 students and 1 teacher feel in a classroom equipped with radiant cooling systems and subjected to uniform convective environments, in lightly warm conditions. The evolution of thermal comfort conditions, using the PMV index, is made by the multi-nodal human thermal comfort model.In this numerical model,

Eusébio Z. E. Conceição; M Lúcio

2011-01-01

166

Thermal management technology for series-parallel HEV  

Microsoft Academic Search

Advanced thermal management system (TMS) has the potential to increase the life of the vehicle's propulsion device and cooling system components as well as decrease fuel consumption and pollutant emission. In this paper a newly advanced TMS with the brake resistor oil cooling sub-system which is suitable for the series-parallel HEV is presented. Two typical thermal management systems for series-parallel

Sun Xiaoxia; Wang Yichun; Wang Facheng

2010-01-01

167

Likely near-term solar-thermal water splitting technologies  

Microsoft Academic Search

Thermodynamic and materials considerations were made for some two- and three-step thermochemical cycles to split water using solar-thermal processing. The direct thermolysis of water to produce H2 using solar-thermal processing is unlikely in the near term due to ultra-high-temperature requirements exceeding 3000K and the need to separate H2 from O2 at these temperatures. However, several lower temperature (<2500K) thermochemical cycles

Christopher Perkins; Alan W. Weimer

2004-01-01

168

Correlation lengths of thermal electromagnetic fields in equilibrium and out of equilibrium conditions  

NASA Astrophysics Data System (ADS)

Spatial coherence of thermal fields in far- and near-field zones generated by heated half-space into vacuum is studied at essentially different thermodynamical conditions. It is shown that correlation lengths of fields in any field zone are different in equilibrium and out of equilibrium systems. In wide range of distances from sample surface correlation functions are should be calculated using a total sum of evanescent and propagating contributions due to their mutual compensation at some conditions because of anticorrelations. It is demonstrated that correlation lengths as calculated with a proposed formula are in agreement with a behavior of correlation functions of thermal fields in spectral range of surface excitations

Dorofeyev, Illarion

2014-11-01

169

The effect of process parameters on the thermal conditions during moving mold ESR  

SciTech Connect

Several experimental melts were conducted using a moving mold electroslag remelting furnace. The conditions of electrode immersion depth, slag cap thickness, and melt current were varied. Mold wall temperatures and slag pool temperatures were measured and the heat flux through the mold wall was calculated. The relationships between varying ESR melt parameters and the resultant thermal conditions were examined. The thermal profile of the mold, the heat transfer to the mold coolant total and fractional, and the formation of a slag skin were studied.

Heilman, J.E. [Carpenter Technology Corp., Reading, PA (United States); Damkroger, B.K. [Sandia National Labs., Albuquerque, NM (United States)

1994-09-01

170

Implementations of electric vehicle system based on solar energy in Singapore assessment of solar thermal technologies  

E-print Network

To build an electric car plus renewable energy system for Singapore, solar thermal technologies were investigated in this report in the hope to find a suitable "green" energy source for this small island country. Among all ...

Liu, Xiaogang, M. Eng. Massachusetts Institute of Technology

2009-01-01

171

OVERVIEW OF CONVENTIONAL AND INNOVATIVE LAND-BASED THERMAL TECHNOLOGIES FOR WASTE DISPOSAL  

EPA Science Inventory

For more than the past two decades, the USEPA has been aggressive in its research, development, performance testing, and in encouragement of the regulated use of proven thermal destruction (or incineration) technologies for the environmentally acceptable treatment and disposal of...

172

Technological change in Swiss thermal waste treatment: An expert-based socio-technical analysis  

SciTech Connect

Understanding technological change provides a crucial basis for governing sustainability transitions. In this paper we present an analysis of technological change using the example of Swiss thermal waste processing. In recent years, increased concerns about the low quality of residues from grate-firing systems led to the examination of alternative technologies. Yet despite clear indications of a potential better performance with respect to residue quality, none of these alternatives has been adopted. Based on a two-stage knowledge integration among 15 leading experts, in a retrospective analysis we identified factors that have significantly affected technological change in Swiss thermal waste processing. These factors were then related to three technological options representing different types of technological change, i.e., from incremental improvements of the existing to the implementation of a new technology. The results indicate that technological change is currently in a technological lock-in and provide detailed insights on the causes. The lock-in results in the step-wise further development of the status quo grate-firing system despite its limitations for improving the residue qualities. Almost all factors (legal, economic, societal, technological) of the existing 'thermal waste management' system have been well adapted to the cost- and energy-efficient grate-firing technology, blocking innovative technologies from entering the Swiss market. In addition, pressures from the context, e.g., societal pressure related to landfill risks, have not been strong enough to promote non-incremental change.

Spoerri, Andy, E-mail: andy.spoerri@env.ethz.c [Institute for Environmental Decisions, Natural and Social Science Interface, ETH Zurich, Universitaetstrasse 22, 8092 Zurich (Switzerland); Lang, Daniel J. [Institute for Environmental Decisions, Natural and Social Science Interface, ETH Zurich, Universitaetstrasse 22, 8092 Zurich (Switzerland); Staeubli, Beat [AWEL, Amt fuer Abfall, Wasser, Energie und Luft, Walchetor, CH-8090 Zurich (Switzerland); Scholz, Roland W. [Institute for Environmental Decisions, Natural and Social Science Interface, ETH Zurich, Universitaetstrasse 22, 8092 Zurich (Switzerland)

2010-07-15

173

Percolation theory applied to the analysis of thermal interface materials in flip-chip technology  

Microsoft Academic Search

A very important aspect in chip design in flip chip technology is the heat dissipation. As the surfaces of the heat sink, the heat spreader and the chip are rough there are imperfect contacts leading to higher thermal resistance due to the contact resistance. A method to decrease this contact resistance is by the use of thermal interface material. These

Amit Devpura; P. E. Phelan; Ravi S. Prasher

2000-01-01

174

Area optimization for leakage reduction and thermal stability in nanometer scale technologies  

Microsoft Academic Search

Traditionally, minimum possible area of a VLSI layout is considered the best for delay and power minimization due to decreased interconnect capacitance. This paper shows however that the use of minimum area does not result in the minimum power and\\/or delay in nanometer scale technologies due to thermal effects, and in some cases, may result in thermal runaway. A methodology

Ja Chun Ku; Yehea Ismail

2006-01-01

175

Thermal Energy for Space Cooling--Federal Technology Alert  

SciTech Connect

Cool storage technology can be used to significantly reduce energy costs by allowing energy-intensive, electrically driven cooling equipment to be predominantly operated during off peak hours when electricity rates are lower. This Federal Technology Alert, which is sponsored by DOE's Federal Energy Management Program (FEMP), describes the basic types of cool storage technologies and cooling system integration options. In addition, it defines the savings potential in the federal sector, presents application advice, and describes the performance experience of specific federal users. The results of a case study of a GSA building using cool storage technology are also provided.

Brown, Daryl R.

2000-12-31

176

Thermal Energy Storage for Space Cooling--Federal Technology Alert  

SciTech Connect

Cool storage technology can be used to significantly reduce energy costs by allowing energy-intensive, electrically driven cooling equipment to be predominantly operated during off peak hours when electricity rates are lower. This Federal Technology Alert, which is sponsored by DOE's Federal Energy Management Program (FEMP), describes the basic types of cool storage technologies and cooling system integration options. In addition, it defines the savings potential in the federal sector, presents application advice, and describes the performance experience of specific federal users. The results of a case study of a GSA building using cool storage technology are also provided.

Brown, Daryl R

2000-12-31

177

Real-time condition monitoring of thermal power plants feed-pumps by rolling bearings supports vibration  

NASA Astrophysics Data System (ADS)

The report addresses the real-time condition monitoring of technical state and automatic diagnosis of auxiliary equipment for bearings supports vibration, for example, control of the feed-pump operating modes of thermal power stations. The causes that lead to premature birth and development of defects in rolling bearings are identified and the development of activities ensuring safe and continuous operation of the auxiliary equipment of thermal power stations is carried out. Collection and analysis of vibration parameters of pumping units during their operation at the operating modes of the technological process are realized by means of real-time technical condition monitoring. Spectral analysis of vibration parameters of one of the pumps showed the presence of frequency components, which mark violations in the operating practices of the pump, the imbalance development and, as a consequence, the development of defects in the bearings by long-term operation of the unit. Timely warning of the personnel on the operation of the unit with the "INTOLERABLE" technical state and automatic warning issuance of the need to change the technological process allowed to recover the estimated pump operation mode in due time and prevent further development of defects in equipment.

Kostyukov, V. N.; Tarasov, E. V.

2012-05-01

178

Fuel Savings and Emission Reductions from Next-Generation Mobile Air Conditioning Technology in India  

SciTech Connect

Up to 19.4% of vehicle fuel consumption in India is devoted to air conditioning (A/C). Indian A/C fuel consumption is almost four times the fuel penalty in the United States and close to six times that in the European Union because India's temperature and humidity are higher and because road congestion forces vehicles to operate inefficiently. Car A/C efficiency in India is an issue worthy of national attention considering the rate of increase of A/C penetration into the new car market, India's hot climatic conditions and high fuel costs. Car A/C systems originally posed an ozone layer depletion concern. Now that industrialized and many developing countries have moved away from ozone-depleting substances per Montreal Protocol obligations, car A/C impact on climate has captured the attention of policy makers and corporate leaders. Car A/C systems have a climate impact from potent global warming potential gas emissions and from fuel used to power the car A/Cs. This paper focuses on car A/C fuel consumption in the context of the rapidly expanding Indian car market and how new technological improvements can result in significant fuel savings and consequently, emission reductions. A 19.4% fuel penalty is associated with A/C use in the typical Indian passenger car. Car A/C fuel use and associated tailpipe emissions are strong functions of vehicle design, vehicle use, and climate conditions. Several techniques: reducing thermal load, improving vehicle design, improving occupants thermal comfort design, improving equipment, educating consumers on impacts of driver behaviour on MAC fuel use, and others - can lead to reduced A/C fuel consumption.

Chaney, L.; Thundiyil, K.; Andersen, S.; Chidambaram, S.; Abbi, Y. P.

2007-01-01

179

A Thermal Model for the Evaluation of Subway Ventilation and Air Conditioning  

Microsoft Academic Search

A thermal model of an existing subway station and 1\\/2 mi of adjacent tunnels are described. The model, developed to evaluate a number of car-cooling and air-conditioning concepts for improved passenger comfort, was programmed for a digital computer to account for transient effects due to train and passenger flow, out-door temperature, humidity conditions, and heat storage in tunnel walls and

William Lassow; E. L. Lustenader; Karl F. Schoch

1972-01-01

180

Heat loss of heat pipelines in moisture conditions of thermal insulation  

NASA Astrophysics Data System (ADS)

Results of numerical simulation of heat and mass transfer in a wet fibroporous material in conditions of evaporation and steam diffusion were obtained. Values of heat and mass fluxes were established. The contribution of evaporation effect to total heat flux and need to consider volume fractions of water and steam into the structure of fibroporous material in calculation of effective thermal conductivity were shown. Nonstationarity of heat and mass transfer in conditions of considered problem can be ignored.

Polovnikov, V. Yu.; Gubina, E. V.

2014-08-01

181

Thermal comfort of an air-conditioned office through different windows-door opening arrangements  

Microsoft Academic Search

This paper investigates the thermal comfort level of an office room through various windows-door opening arrangements in hot and humid climate. To determine the windows-door opening performance, 14 opening configurations have been considered and the combination of opening arrangements was carried out in an air-conditioned office at UPM, Malaysia. After conducting objective measurement for each condition, Predicted Mean Vote (PMV)

R. Daghigh; NM Adam; K. Sopian; BB Sahari

2009-01-01

182

Comparing Microchannel Technologies to Minimize the Thermal Stack and Improve Thermal Performance in Hybrid Electric Vehicles  

Microsoft Academic Search

Hybrid electric vehicles for military applications require advanced cooling to ensure peak power electronics performance and reliability. Two methods of reducing overall thermal resistivity by integrating microchannel coolers into the power electronics thermal stack are explored. The first approach involves silicon manifold microchannel coolers with direct fluid impingement on the semiconductor die. The second involves fabricating standard, parallel microchannels into

Nicholas R. Jankowski; Lauren Everhart; Brian Morgan; Bruce Geil; Patrick McCluskey

2007-01-01

183

Thermal Infrared Imaging Spectrometer - An advanced optics technology instrument  

NASA Technical Reports Server (NTRS)

Through the use of a special optical filter, the Thermal Infrared Imaging Spectrometer, an airborne multispectral IR imaging instrument operating in the thermal emission region (7.5-14 microns), will achieve signal-to-noise ratios greater than 600 with ambient temperature optics. This instrument will be used to do compositional surface mapping of the terrain, and will refine the ability to categorize rock families and types by providing much higher spectral resolution in the emission region than was previously available. Details of the optical system, the detector, the cooler system, and the support electronics are described.

Mahoney, Colin; Labaw, Clayton; Sobel, Harold; Kahle, Anne

1990-01-01

184

Thermal and structural performance of GRP panels and short columns under fire conditions  

Microsoft Academic Search

This paper presents the results of an experimental study of the behaviour of different types of GRP structures under fire conditions. The experiments were conducted in two stages. The first part is concerned with the thermal performance of GRP sandwich panels and stringer systems when exposed to fire on one side. The objective of this study is to provide experimental

P. M. Currie; Yong Wang; J. M. Davies

2003-01-01

185

Thermal hazard analysis of styrene monomer at Low temperature conditions during storage and transportation  

E-print Network

1 Thermal hazard analysis of styrene monomer at Low temperature conditions during storage Abstract Styrene Monomer (SM) has been widely used for producing polystyrene (PS), acrylonitrile-butadiene-styrene (ABS) and styrene-acryonitrile (SAN) in the petrochemical industry. From 1994 to 2001, several serious

Chen, Shu-Ching

186

Onset of natural convection in a horizontal porous medium with mixed thermal boundary conditions  

Microsoft Academic Search

The mathematical formalism developed by Nield (1968) has been used to calculate critical Rayleigh numbers and critical wavenumbers for the onset of natural convection in a horizontal porous medium subject to mixed thermal boundary conditions. Two practically important cases were examined. The first case corresponds to impermeable top and bottom boundaries, and the second corresponds to an impermeable bottom boundary

K. E. Wilkes

1995-01-01

187

Direct Measurement of the Thermal Diffusivity of Molten Iron at Outer Core Conditions  

NASA Astrophysics Data System (ADS)

The thermal conductivity of liquid core is an important physical property for both the thermal evolution of the core and the operation of the geodynamo. Unlike the situation in the mantle, the high conductivity of liquid metal in the core permits a substantial fraction of the heat flow through the core to be carried by conduction along the adiabatic gradient. Only the residual heat flow in excess of that conducted along the adiabatic gradient is available to power the geodynamo. Current estimates suggest that 50% or more of the heat flow out of the core is carried by conduction along the adiabat. Additional sources of energy for the geodynamo are supplied at the present time by latent heat release and chemical fractionation as the liquid core solidifies. Prior to the formation of the solid inner core the geodynamo must run on heat alone, and the high thermal conductivity places a heavy demand on primordial heat when there are no other sources of heat (such as radioactivity). Numerous studies have proposed radioactive heat sources in the core to avoid implausibly high temperatures in the core at early times. An alternative solution could be found by lowering the thermal conductivity, which lowers the heat flow needed to power the geodynamo prior to the formation of the inner core. A 50% reduction in current estimates of the thermal conductivity maybe sufficient to eliminate the need for radioactive heating, and is within the current uncertainties for this important parameter. A new experimental technique for measuring thermal diffusivity of liquids at outer core conditions will be presented. This technique departs from conventional approaches that rely on the transmission of thermal pulses. Instead, the method uses scattered light and its interaction with thermal dissipation mechanisms to determine the total thermal diffusivity (vibrational and electronic contributions). Preliminary data for molten iron will be presented.

Heinz, D. L.; Buffett, B. A.

2008-05-01

188

Porous materials produced from incineration ash using thermal plasma technology.  

PubMed

This study presents a novel thermal plasma melting technique for neutralizing and recycling municipal solid waste incinerator (MSWI) ash residues. MSWI ash residues were converted into water-quenched vitrified slag using plasma vitrification, which is environmentally benign. Slag is adopted as a raw material in producing porous materials for architectural and decorative applications, eliminating the problem of its disposal. Porous materials are produced using water-quenched vitrified slag with Portland cement and foaming agent. The true density, bulk density, porosity and water absorption ratio of the foamed specimens are studied here by varying the size of the slag particles, the water-to-solid ratio, and the ratio of the weights of the core materials, including the water-quenched vitrified slag and cement. The thermal conductivity and flexural strength of porous panels are also determined. The experimental results show the bulk density and the porosity of the porous materials are 0.9-1.2 g cm(-3) and 50-60%, respectively, and the pore structure has a closed form. The thermal conductivity of the porous material is 0.1946 W m(-1) K(-1). Therefore, the slag composite materials are lightweight and thermal insulators having considerable potential for building applications. PMID:23948051

Yang, Sheng-Fu; Chiu, Wen-Tung; Wang, To-Mai; Chen, Ching-Ting; Tzeng, Chin-Ching

2014-06-01

189

TECHNOLOGY ASSESSMENT OF SOLAR THERMAL ENERGY APPLICATIONS IN WASTEWATER TREATMENT  

EPA Science Inventory

Three major areas were identified for which solar thermal energy usage has potential applicability in Publicly Owned Treatment Works. These areas include space and domestic water heating, anaerobic digester heating, and sludge drying. The report contains a detailed analysis of so...

190

CALORSTOCK 1994: Thermal energy storage. Better economy, environment, technology  

NASA Astrophysics Data System (ADS)

This publication is the second volume of the Proceedings of CALORSTOCK'94, the Sixth International Conference on Thermal Energy Storage held in Espoo, Finland on 22-25 Aug. 1994. This volume contains 51 presentations from the following six sessions: Chemical storage; Heat storage and environment; Central solar heating plants with seasonal storage; Water storage pits and tanks; Cooling; and National activities.

Kangas, M. T.; Lund, P. D.

191

SITE TECHNOLOGY CAPSULE: CLEAN BERKSHIRES, INC. THERMAL DESORPTION SYSTEM  

EPA Science Inventory

The thermal desorption process devised by Clean Berkshires, Inc., works by vaporizing the organic contaminants from the soil with heat, isolating the contaminant! in a gas stream, and then destroying them in a high efficiency afterburner. The processed solids are either replaced ...

192

SITE TECHNOLOGY CAPSULE: CLEAN BERKSHIRES, INC. - THERMAL DESORPTION SYSTEM  

EPA Science Inventory

The thermal desorption process devised by Clean Berkshires, Inc., works by vaporizing the organic contaminants from the soil with heat, isolating the contaminant! in a gas stream, and then destroying them in a high efficiency afterburner. he processed solids are either replaced f...

193

Thermal neutral format based on the step technology  

NASA Technical Reports Server (NTRS)

The exchange of models is one of the most serious problems currently encountered in the practice of spacecraft thermal analysis. Essentially, the problem originates in the diversity of computing environments that are used across different sites, and the consequent proliferation of native tool formats. Furthermore, increasing pressure to reduce the development's life cycle time has originated a growing interest in the so-called spacecraft concurrent engineering. In this context, the realization of the interdependencies between different disciplines and the proper communication between them become critical issues. The use of a neutral format represents a step forward in addressing these problems. Such a means of communication is adopted by consensus. A neutral format is not directly tied to any specific tool and it is kept under stringent change control. Currently, most of the groups promoting exchange formats are contributing with their experience to STEP, the Standard for Exchange of Product Model Data, which is being developed under the auspices of the International Standards Organization (ISO 10303). This paper presents the different efforts made in Europe to provide the spacecraft thermal analysis community with a Thermal Neutral Format (TNF) based on STEP. Following an introduction with some background information, the paper presents the characteristics of the STEP standard. Later, the first efforts to produce a STEP Spacecraft Thermal Application Protocol are described. Finally, the paper presents the currently harmonized European activities that follow up and extend earlier work on the area.

Almazan, P. Planas; Legal, J. L.

1995-01-01

194

Real-time bicycle detection at signalized intersections using thermal imaging technology  

NASA Astrophysics Data System (ADS)

More and more governments and authorities around the world are promoting the use of bicycles in cities, as this is healthy for the bicyclist and improves the quality of life in general. Safety and efficiency of bicyclists has become a major focus. To achieve this, there is a need for a smarter approach towards the control of signalized intersections. Various traditional detection technologies, such as video, microwave radar and electromagnetic loops, can be used to detect vehicles at signalized intersections, but none of these can consistently separate bikes from other traffic, day and night and in various weather conditions. As bikes should get a higher priority and also require longer green time to safely cross the signalized intersection, traffic managers are looking for alternative detection systems that can make the distinction between bicycles and other vehicles near the stop bar. In this paper, the drawbacks of a video-based approach are presented, next to the benefits of a thermal-video-based approach for vehicle presence detection with separation of bicycles. Also, the specific technical challenges are highlighted in developing a system that combines thermal image capturing, image processing and output triggering to the traffic light controller in near real-time and in a single housing.

Collaert, Robin

2013-02-01

195

Impact of technological processing conditions on optical properties of inorganic-organic hybrid polymers  

NASA Astrophysics Data System (ADS)

Nanostructured materials are intensively investigated due to their wide range of physical and chemical properties which result in a large variety of applications. From an industrial point of view, emphasis has not only to be on materials performance and on control of their properties, but also on cost reduction either for the materials, the processes, or for both. Materials are searched for which enable different processing technologies, feature sizes and shapes as well as an integration up to a centimeter scale. The combination of low-cost materials with tunable material parameters such as low optical absorption, tunable refractive index, good processability as well as high chemical, thermal and mechanical stability, is very attractive for integrated optical applications. A particular class of low-cost nanoscale materials which fulfills these requirements is the class of inorganic-organic hybrid polymers (ORMOCER(R)s1) which are synthesized by catalytically controlled hydrolysis/ polycondensation reactions, resulting in storage-stable, photo-sensitive resins. The material properties, for example refractive index or optical absorption, can be widely varied by choice of alkoxysilane precursors or synthesis conditions such as catalysts or solvents. In addition, the material properties can also be significantly influenced by the technological processing conditions. For example, the degree of organic cross-linking can be adjusted by variation of UV initiator kind and concentration, or by various exposure doses. This, consequently, is directly correlated to the refractive index. The impact of processing conditions on the refractive index was investigated by FTIR spectroscopy and refractive index measurements. The refractive indices are correlated to the material's degree of organic cross-linking, and application examples will be given.

Bock, Anne; Pieper, Torsten; Houbertz, Ruth; Sextl, Gerhard

2009-02-01

196

Performance Testing of Thermal Interface Filler Materials in a Bolted Aluminum Interface Under Thermal/Vacuum Conditions  

NASA Technical Reports Server (NTRS)

A thermal interface material is one of the many tools that are often used as part of the thermal control scheme for space-based applications. These materials are placed between, for example, an avionics box and a cold plate, in order to improve the conduction heat transfer so that proper temperatures can be maintained. Historically at Marshall Space Flight Center, CHO-THERM@ 1671 has primarily been used for applications where an interface material was deemed necessary. However, there have been numerous alternatives come on the market in recent years. It was decided that a number of these materials should be tested against each other to see if there were better performing alternatives. The tests were done strictly to compare the thermal performance of the materials relative to each other under repeatable conditions and they do not take into consideration other design issues such as off-gassing, electrical conduction or isolation, etc. This paper details the materials tested, test apparatus, procedures, and results of these tests.

Glasgow, Shaun; Kittredge, Ken

2003-01-01

197

Effect of soil water content on soil thermal conductivity under field conditions  

NASA Astrophysics Data System (ADS)

Knowledge of the thermal properties of soils is required in many areas of engineering, meteorology, agronomy, and ecosystem and soil science. Soil thermal conductivity varies in time and space, since it is influenced by soil properties as well as soil temperature and moisture conditions. We use the one dimensional heat conduction equation in conjunction with two-year data measured in a grass-covered field in North Carolina Piedmont to estimate soil thermal conductivity and to investigate how it is impacted by water content. In agreement with laboratory experiments reported in the literature, our results suggest that under dry conditions soil thermal conductivity increases across a relatively narrow range of soil water contents, above which a further increase in water content does not significantly change thermal conductivity. However, when soil approaches saturation, heat transfer is further improved, a fact not previously noted. This nonlinear behavior is consistent with the formation at high water contents of a continuous film of liquid water in soil aggregates of mineral and organic matter.

Vico, G.; Daly, E.; Manzoni, S.; Porporato, A.

2008-12-01

198

Stability of Lysozyme in Aqueous Extremolyte Solutions during Heat Shock and Accelerated Thermal Conditions  

PubMed Central

The purpose of this study was to investigate the stability of lysozyme in aqueous solutions in the presence of various extremolytes (betaine, hydroxyectoine, trehalose, ectoine, and firoin) under different stress conditions. The stability of lysozyme was determined by Nile red Fluorescence Spectroscopy and a bioactivity assay. During heat shock (10 min at 70°C), betaine, trehalose, ectoin and firoin protected lysozyme against inactivation while hydroxyectoine, did not have a significant effect. During accelerated thermal conditions (4 weeks at 55°C), firoin also acted as a stabilizer. In contrast, betaine, hydroxyectoine, trehalose and ectoine destabilized lysozyme under this condition. These findings surprisingly indicate that some extremolytes can stabilize a protein under certain stress conditions but destabilize the same protein under other stress conditions. Therefore it is suggested that for the screening extremolytes to be used for protein stabilization, an appropriate storage conditions should also be taken into account. PMID:24465983

van Streun, Erwin L. P.; Frijlink, Henderik W.; Hinrichs, Wouter L. J.

2014-01-01

199

Determination of the effective thermal conductivity of granular materials under varying pressure conditions  

NASA Astrophysics Data System (ADS)

We report on thermal conductivity measurements performed on glass spheres of different grain sizes under varying pressure conditions ranging from 10-5 up to 1000 hPa. Glass spheres of 0.1 up to 4.3 mm were used as an analogue for the coarse-grained fractions of planetary regolith. From the obtained conductivity versus pressure data, sample pore sizes were derived and compared to estimated pore sizes. An increasing difference between derived and estimated pore size with increasing grain size was found. The behavior of the granular matter with decreasing pressure was analyzed by estimating the Knudsen number for the given system. The results indicate a high variability of the effective thermal conductivity for Martian conditions. Furthermore, the results imply that the thermal conductivity reaches a grain size-dependent, but pressure-independent, value for pressures below 0.01 hPa. For vacuum conditions a linear relation between grain size and effective thermal conductivity was found. Additionally, a mixture was analyzed, which showed a stronger decrease with gas pressure compared to the single-sized samples. From the pore size derived for the mixture an ``effective'' grain size composed of weighted mean of the mixture components was determined.

Huetter, E. S.; Koemle, N. I.; Kargl, G.; Kaufmann, E.

2008-12-01

200

Desalination of Seawater by Thermal Distillation and Electrodialysis Technologies  

Microsoft Academic Search

\\u000a Freshwater is one of the scarce resources in the world. In many countries, due to freshwater shortages, searching for freshwater\\u000a resources has become extremely important and desalination is known to be an essential available solution for this. In this\\u000a chapter, the thermal distillation of multistage flash distillation, multieffect distillation and vapor compression and electrodialysis\\u000a processes for seawater desalination are presented.

Jiaping Paul Chen; Lawrence K. Wang; Lei Yang; Yu-Ming Zheng

201

Emerging MOSFET packaging technologies and their thermal evaluation  

Microsoft Academic Search

Major MOSFET manufacturers have recently introduced innovative packaging options to achieve the next level of breakthroughs in electrical and thermal performance. Some of the innovations involve replacement of wire-bonds with solder-bumps for device interconnections in power devices and reduction in number of interfaces\\/paths for heat dissipation. The overall goal is to achieve small form factor MOSFET packages with significant improvements

Xuejun Fan; S. Haque

2002-01-01

202

Supporting technology for enhanced oil recovery - EOR thermal processes  

SciTech Connect

This report contains the results of efforts under the six tasks of the Eighth Amendment and Extension of Annex IV, Enhanced Oil Recovery Thermal Processes of the Venezuela/USA Agreement. The report is presented in sections and each section contains one or more reports prepared by various individuals or groups describing the results of efforts under each of the tasks. A statement of each task, taken from the agreement, is presented on the first page of each section.

NONE

1995-03-01

203

Rapid thermal technologies for high-efficiency silicon solar cells  

Microsoft Academic Search

This paper shows that rapidly formed emitters in less than 6min in the hot zone of a conveyor belt furnace or in 3min in an rapid thermal processing (RTP) system, in conjunction with a screen-printed (SP) RTP Al-BSF and passivating oxide formed simultaneously in 2min can produce very simple high-efficiency n+-p-p+ cells with no surface texturing, point contacts, or selective

A. Ebong; Y. H. Cho; M. Hilali; A. Rohatgi; D. Ruby

2002-01-01

204

Technology Demonstration: Acoustic Condition Assessment of Wastewater Collection Systems  

EPA Science Inventory

The overall objective of this demonstration project was to evaluate technologies that are designed for rapid deployment using portable equipment that can result in significant cost-savings to wastewater utilities. Smaller diameter pipes (i.e., less than 12-inch diameter) are gen...

205

Comparison of Dynamic Characteristics for an Inflatable Solar Concentrator in Atmospheric and Thermal Vacuum Conditions  

NASA Technical Reports Server (NTRS)

Dynamic testing of an inflatable solar concentrator structure in a thermal vacuum chamber as well as in ambient laboratory conditions is described in detail. Unique aspects of modal testing for the extremely lightweight inflatable are identified, including the use of a noncontacting laser vibrometer measurement system. For the thermal vacuum environment, mode shapes and frequency response functions are compared for three different test article inflation pressures at room temperature. Modes that persist through all the inflation pressure regimes are identified, as well as modes that are unique for each pressure. In atmospheric pressure and room temperature conditions, dynamic measurements were obtained for the expected operational inflation pressure of 0.5 psig. Experimental mode shapes and frequency response functions for ambient conditions are described and compared to the 0.5 psig results from the thermal vacuum tests. Only a few mode shapes were identified that occurred in both vacuum and atmospheric environments. This somewhat surprising result is discussed in detail, and attributed at least partly to 1.) large differences in modal damping, and 2.) significant differences in the mass of air contained by the structure, in the two environments. Results of this investigation point out the necessity of testing inflatable space structures in vacuum conditions before they can be launched. Ground testing in atmospheric pressure is not sufficient for predicting on-orbit dynamics of non-rigidized inflatable systems.

Slade, Kara N.; Tinker, Michael L.; Lassiter, John O.; Engberg, Robert

2000-01-01

206

A new power module packaging technology for enhanced thermal performance  

Microsoft Academic Search

A new approach to packaging high performance power devices, Chip on Flex Power Overlay (POL) was presented. It was shown that the GE's cost effective POL power packaging technology is ideally suited for high heat flux and high performance applications. This is primarily due to the elimination of bond wires and the planar geometry which offers cooling of power devices

B. Ozmat; C. S. Korman; P. McConnelee; M. Kheraluwala; E. Delgado; R. Fillion

2000-01-01

207

Evaluation of critical nuclear power plant electrical cable response to severe thermal fire conditions  

NASA Astrophysics Data System (ADS)

The failure of electrical cables exposed to severe thermal fire conditions are a safety concern for operating commercial nuclear power plants (NPPs). The Nuclear Regulatory Commission (NRC) has promoted the use of risk-informed and performance-based methods for fire protection which resulted in a need to develop realistic methods to quantify the risk of fire to NPP safety. Recent electrical cable testing has been conducted to provide empirical data on the failure modes and likelihood of fire-induced damage. This thesis evaluated numerous aspects of the data. Circuit characteristics affecting fire-induced electrical cable failure modes have been evaluated. In addition, thermal failure temperatures corresponding to cable functional failures have been evaluated to develop realistic single point thermal failure thresholds and probability distributions for specific cable insulation types. Finally, the data was used to evaluate the prediction capabilities of a one-dimension conductive heat transfer model used to predict cable failure.

Taylor, Gabriel James

208

Formation of separating layers under conditions of the thermal aging of sorbents modified by fluorinated polyimide  

NASA Astrophysics Data System (ADS)

Thermogravimetry, elemental analysis, low-temperature nitrogen adsorption, high-resolution electron microscopy, and gas chromatography are used to study the effect of the content of perfluorinated polyimide when used as a stationary phase for modifying Chromosorb P NAW diatomite supports and aluminum oxide, and the effect of thermal aging conditions on changes in their texture and chromatographic characteristics. It is shown that Chromosorb P NAW + 5 wt % of polyimide (PI) adsorbent thermally aged at 700°C in a flow of inert gas exhibits properties of carbon molecular sieves, while aluminum oxide impregnated with 10 wt % of PI and thermally aged at 250°C allows us to selectively separate permanent and organic gases, as well separate saturated and unsaturated hydrocarbons.

Yakovleva, E. Yu.; Shundrina, I. K.; Gerasimov, E. Yu.; Vaganova, T. A.

2014-03-01

209

Development of adsorption air-conditioning technology using modified activated carbon – A review  

Microsoft Academic Search

Adsorption air-conditioning technology has attracted much attention recently due to its environmental friendly property. Some successes have been reported in the literature on the adsorption technology for air-conditioning applications. This paper presents an overview of the researches which had been carried out on adsorption refrigeration system with the commonly used adsorbent and adsorbate working pairs, solar adsorption refrigeration and adsorption

T. H. C. Yeo; I. A. W. Tan; M. O. Abdullah

2012-01-01

210

A Rubric for Self-Assessment of Essential Technology Conditions in Schools  

ERIC Educational Resources Information Center

This article describes the development of a Web-based instrument that is part of a strategic planning initiative in technology in K-12 schools in Nebraska. The instrument provides rubrics for self-assessment of essential conditions necessary for integrating and adopting of technology. Essential conditions were defined by an extended panel of…

Steckelberg, Allen L.; Li, Lan; Liu, Xiongyi; Kozak, Mike

2008-01-01

211

Field Demonstration of Electro-Scan Defect Location Technology for Condition Assessment of Wastewater Collection Systems  

EPA Science Inventory

The purpose of the field demonstration program is to gather technically reliable cost and performance information on selected condition assessment technologies under defined field conditions. The selected technologies include zoom camera, electro-scan (FELL-41), and a multi-sens...

212

Systematic comparison of mechanical and thermal sludge disintegration technologies.  

PubMed

This study presents a systematic comparison and evaluation of sewage sludge pre-treatment by mechanical and thermal techniques. Waste activated sludge (WAS) was pre-treated by separate full scale Thermo-Pressure-Hydrolysis (TDH) and ball milling facilities. Then the sludge was processed in pilot-scale digestion experiments. The results indicated that a significant increase in soluble organic matter could be achieved. TDH and ball milling pre-treatment could offer a feasible treatment method to efficiently disintegrate sludge and enhance biogas yield of digestion. The TDH increased biogas production by ca. 75% whereas ball milling allowed for an approximately 41% increase. The mechanisms of pre-treatment were investigated by numerical modeling based on Anaerobic Digestion Model No. 1 (ADM1) in the MatLab/SIMBA environment. TDH process induced advanced COD-solubilisation (COD(soluble)/COD(total)=43%) and specifically complete destruction of cell mass which is hardly degradable in conventional digestion. While the ball mill technique achieved a lower solubilisation rate (COD(soluble)/COD(total)=28%) and only a partial destruction of microbial decay products. From a whole-plant prospective relevant release of ammonia and formation of soluble inerts have been observed especially from thermal hydrolysis. PMID:20060704

Wett, B; Phothilangka, P; Eladawy, A

2010-06-01

213

Thermoelectric power enhancement by way of flow impedance for fixed thermal input conditions  

NASA Astrophysics Data System (ADS)

Liquid-to-liquid thermoelectric generators are now being considered for the purpose of converting low cost heat to electricity for local energy uses. The importance in investigating their system efficiency lies in the fact that the generator's purpose is to maintain a heat source and a heat sink for its embedded thermoelectric modules. Of particular importance is the generator's ability to maintain an asymmetric thermal field across its embedded modules since this mechanism partially dictates the devices' thermal to electric conversion efficiency. Indeed, since the modules' semiconductor materials' ability to generate an electromotive force is dependent on the quality of the thermal dipole across the material, gains in thermoelectric generator energy conversion efficiency are made possible with thermal system management. In an effort to improve the system conversion efficiency of a liquid-to-liquid thermoelectric generator (TEG), the present work builds upon recent advancements in TEG inner pipe flow optimisation by investigating the thermoelectric power enhancement brought upon by flow impeding panel inserts in a thermoelectric generator's flow channels for fixed thermal input conditions and with respect to varying insert panel densities. The pumping penalty associated with the flow impedance is measured in order to present and to discuss the net thermoelectric power enhancement.

Amaral, Calil; Brandão, Caio; Sempels, Éric V.; Lesage, Frédéric J.

2014-12-01

214

Graphite Ablation and Thermal Response Simulation Under Arc-Jet Flow Conditions  

NASA Technical Reports Server (NTRS)

The Two-dimensional Implicit Thermal Response and Ablation program, TITAN, was developed and integrated with a Navier-Stokes solver, GIANTS, for multidimensional ablation and shape change simulation of thermal protection systems in hypersonic flow environments. The governing equations in both codes are demoralized using the same finite-volume approximation with a general body-fitted coordinate system. Time-dependent solutions are achieved by an implicit time marching technique using Gauess-Siedel line relaxation with alternating sweeps. As the first part of a code validation study, this paper compares TITAN-GIANTS predictions with thermal response and recession data obtained from arc-jet tests recently conducted in the Interaction Heating Facility (IHF) at NASA Ames Research Center. The test models are graphite sphere-cones. Graphite was selected as a test material to minimize the uncertainties from material properties. Recession and thermal response data were obtained from two separate arc-jet test series. The first series was at a heat flux where graphite ablation is mainly due to sublimation, and the second series was at a relatively low heat flux where recession is the result of diffusion-controlled oxidation. Ablation and thermal response solutions for both sets of conditions, as calculated by TITAN-GIANTS, are presented and discussed in detail. Predicted shape change and temperature histories generally agree well with the data obtained from the arc-jet tests.

Chen, Y.-K.; Milos, F. S.; Reda, D. C.; Stewart, D. A.; Venkatapathy, Ethiraj (Technical Monitor)

2002-01-01

215

Technology to Empower Patients with Chronic Conditions Kay Connelly  

E-print Network

have saved to determine that she needed to remove sugar from her diet? This is a true story. This is my of a condition, giving the #12;patient time to take defensive measures (e.g. take a migraine pill). The second

Connelly, Kay

216

Potential of Using New Technology for Estimating Body Condition Scores  

Microsoft Academic Search

Although the benefits of body condition scoring (BCS) are intuitive to most dairy industry professionals, relatively few dairy farms have incorporated it as part of their routine management strategy. The lack of adoption of this technique is largely attributable to subjectivity and time requirements. An automated BCS system would be less demanding of time by trained personnel, less stressful to

Jeffrey M. Bewley; Michael M. Schutz

2009-01-01

217

Optimization of Remediation Conditions using Vadose Zone Monitoring Technology  

NASA Astrophysics Data System (ADS)

Success of in-situ bio-remediation of the vadose zone depends mainly on the ability to change and control hydrological, physical and chemical conditions of subsurface. These manipulations enables the development of specific, indigenous, pollutants degrading bacteria or set the environmental conditions for seeded bacteria. As such, the remediation efficiency is dependent on the ability to implement optimal hydraulic and chemical conditions in deep sections of the vadose zone. Enhanced bioremediation of the vadose zone is achieved under field conditions through infiltration of water enriched with chemical additives. Yet, water percolation and solute transport in unsaturated conditions is a complex process and application of water with specific chemical conditions near land surface dose not necessarily result in promoting of desired chemical and hydraulic conditions in deeper sections of the vadose zone. A newly developed vadose-zone monitoring system (VMS) allows continuous monitoring of the hydrological and chemical properties of the percolating water along deep sections of the vadose zone. Implementation of the VMS at sites that undergoes active remediation provides real time information on the chemical and hydrological conditions in the vadose zone as the remediation process progresses. Manipulating subsurface conditions for optimal biodegradation of hydrocarbons is demonstrated through enhanced bio-remediation of the vadose zone at a site that has been contaminated with gasoline products in Tel Aviv. The vadose zone at the site is composed of 6 m clay layer overlying a sandy formation extending to the water table at depth of 20 m bls. The upper 5 m of contaminated soil were removed for ex-situ treatment, and the remaining 15 m vadose zone is treated in-situ through enhanced bioremedaition. Underground drip irrigation system was installed below the surface on the bottom of the excavation. Oxygen and nutrients releasing powder (EHCO, Adventus) was spread below the irrigation system to enrich the percolating water. The vadose zone monitoring system that was installed at the site allowed accurate monitoring of the wetting cycles, including: (1) wetting front propagation velocities, (2) temporal variation of the sediment water content, (2) chemical composition of the percolating water, (3) isotopic composition of BTEX compounds, (4) variations in nutrient concentration, and (5) variations in the vadose zone redox potential. Preliminary results showed that the wetting front crossed the entire vadose zone in four days reaching maximum water content values of 12 to 18 %. Temporal variation in the sediment BTEX concentrations indicated significant reduction in highly soluble and mobile compounds such as MTBE. Yet the chemical composition of the water samples through the first sampling campaign indicated that the limiting factor for biodegradation at the first wetting cycle was insufficient nitrogen. Results from each wetting cycles were used to improve the following wetting cycles in order to optimize the vadose zone conditions for microbial activity while minimizing leaching of contaminants to the groundwater.

Dahan, O.; Mandelbaum, R.; Ronen, Z.

2010-12-01

218

The effect of solar radiation on the thermal environment inside the air-conditioned automobile chamber  

SciTech Connect

The distribution of solar radiant energy inside the specific air-conditioned automobile chamber is studied on the basis of the unique wavelength spectrum. Some important optical parameters of the internal materials are mostly determined by experiments with monochromator, electron-multiplier phototube, etc. Some optical parameters of the thin transparent object are analyzed theoretically. Based on random model, Monte Carlo method is adopted to get the detailed distribution of solar radiant energy. The procedures of absorptivity, reflection and transmission of each ray are simulated and traced during the calculation. The universal software calculates two cases with different kind of glass. The relevant results show the importance of solar radiant energy on the thermal environment inside the air-conditioned automobile chamber. Furthermore, the necessity of shield quality of the automobile glass is also obvious. This study is also the basis of the following researches on fluid and temperature fields. The results are also useful for further thermal comfort design.

Tong, L.; Yang, K.; Chen, Z.

1999-07-01

219

Flip-chip interconnection technology for advanced thermal conduction modules  

Microsoft Academic Search

Area array solder bumps on silicon devices, known as C4 balls, have been successfully used in terminating logic and memory devices to ceramic substrates in numerous IBM products over two decades. With the IBM System 390\\/ES9000 series of mainframe computers, this highly reliable chip termination technology has achieved improved interconnection density and total number of chip I\\/O connections per module.

S. K. Ray; K. Beckham; R. Master

1991-01-01

220

Hypothetical accident conditions, free drop and thermal tests: Specification 6M  

Microsoft Academic Search

The 30 gallon Specification 6M shipping container with rolled-top food pack cans as inner containers is evaluated under conditions required by 10 CFR 71.42. One kilogram of depleted uranium as UOâ was packaged in each of the inner containers. After completion of a free drop test and a simulated thermal test, the maximum observed leakage of UOâ for the following

1980-01-01

221

Distribution of coral reefs in the Pearl Islands (Gulf of Panama) in relation to thermal conditions  

Microsoft Academic Search

The hypothesis that coral reefs are largely confined to the north and east sides of islands because of favorable thermal conditions was tested and confirmed in the Pearl Islands, Panama. The growth rate of Pocillopom dumicornis, the chief reef-building species, declined mark- edly or ceased on shores exposed to temperatures in the range 2%21°C when median growth rates dropped to

PETER W. GLYNN; ROBERT H. STEWART

1973-01-01

222

Numerical Investigation of Thermal Stress Convention in Nonisothermal Gases Under Microgravity Conditions  

NASA Technical Reports Server (NTRS)

Reported here are our results of our numerical/theoretical investigation into the effects of thermal stress in nonisothermal gases under microgravity conditions. The first part of the report consists of a brief summary of the accomplishments and conclusions of our work. The second part consists of two manuscripts, one being a paper presented at the 1998 MSAD Fluid Physics workshop, and the other to appear in Physics of Fluids.

Mackowski, D. W.

1999-01-01

223

Internal thermotopography and shifts in general thermal balance in man under special heat transfer conditions  

NASA Technical Reports Server (NTRS)

Thermal regulation for astronauts working in pressure suits in open space provides for protection by a system of artificial heat removal and compensation to counteract possible changes in the heat regulating function of the human body that occur under the complex effects of space flight conditions. Most important of these factors are prolonged weightlessness, prolonged limitation of motor activity, and possible deviations of microclimatic environmental parameters.

Gorodinskiy, S. M.; Gramenitskiy, P. M.; Kuznets, Y. I.; Ozerov, O. Y.; Yakovleva, E. V.; Groza, P.; Kozlovskiy, S.; Naremski, Y.

1974-01-01

224

Changes induced in the thermal properties of Galizian soils by the heating in laboratory conditions  

Microsoft Academic Search

The soil properties can be strongly affected by wildfires, causing direct effects on ecosystem productivity and sustainability.\\u000a These effects depend, among other things, on the soil type and on the temperature reached during the fire. The variations\\u000a of thermal properties of several Galizian soils heated in an oven in laboratory conditions at different temperatures (200–500 °C)\\u000a during 15 min have been examined

P. V. Verdes; J. Salgado

2011-01-01

225

Technology update: bronchoscopic thermal vapor ablation for managing severe emphysema  

PubMed Central

Bronchoscopic thermal vapor ablation (BTVA) is an endoscopic lung volume reduction therapy that presents an effective treatment approach in patients with severe upper lobe-predominant emphysema. By instillation of heated water vapor, an inflammatory reaction is induced, leading to fibrosis and scarring of the lung parenchyma, resulting in lobar volume reduction. Clinical single-arm trials demonstrated great outcomes, with significant improvement of lung function, exercise capacity, and quality of life. As the BTVA-induced local inflammatory response that seems to be essential for the desired lobar volume reduction can be associated with transient clinical worsening, strict monitoring of the patients is required. In future, the balance between efficacy and safety will constitute a major challenge. This review summarizes the BTVA procedure, the mechanism of action, and the results of the clinical trials, including the efficacy and safety data. PMID:25336993

Gompelmann, Daniela; Eberhardt, Ralf; Herth, Felix JF

2014-01-01

226

Development of the Variable Emittance Thermal Suite for the Space Technology 5 Microsatellite  

NASA Technical Reports Server (NTRS)

The advent of very small satellites, such as nano and microsatellites, logically leads to a requirement for smaller thermal control subsystems. In addition, the thermal control needs of the smaller spacecraft/instrument may well be different from more traditional situations. For example, power for traditional heaters may be very limited or unavailable, mass allocations may be severely limited, and fleets of nano/microsatellites will require a generic thermal design as the cost of unique designs will be prohibitive. Some applications may require significantly increased power levels while others may require extremely low heat loss for extended periods. Small spacecraft will have low thermal capacitance thus subjecting them to large temperature swings when either the heat generation rate changes or the thermal sink temperature changes. This situation, combined with the need for tighter temperature control, will present a challenging situation during transient operation. The use of "off-the-shelf" commercial spacecraft buses for science instruments will also present challenges. Older thermal technology, such as heaters, thermostats, and heat pipes, will almost certainly not be sufficient to meet the requirements of these new spacecraft/instruments. They are generally too heavy, not scalable to very small sizes, and may consume inordinate amounts of power. Hence there is a strong driver to develop new technology to meet these emerging needs. Variable emittance coatings offer an exciting alternative to traditional control methodologies and are one of the technologies that will be flown on Space Technology 5, a mission of three microsatellites designed to validate "enabling" technologies. Several studies have identified variable emittance coatings as applicable to a wide range of spacecraft, and to potentially offer substantial savings in mass and/or power over traditional approaches. This paper discusses the development of the variable emittance thermal suite for ST-5. More specifically, it provides a description of and the infusion and validation plans for the variable emittance coatings.

Douglas, Donya M.; Swanson, Theodore; Osiander, Robert; Champion, John; Darrin, Ann Garrison; Biter, William; Chandrasekhar, Prasanna; Obenschain, Arthur (Technical Monitor)

2001-01-01

227

Integration of Thermal Indoor Conditions into Operational Heat Health Warning Systems  

NASA Astrophysics Data System (ADS)

The 2003 heat wave in Western Europe with altogether 35,000 to 50,000 deaths in Europe, several thousands of which occurred in Germany, has clearly pointed out the danger arising from long periods with high heat load. As a consequence, Germany, as many other European countries, has started to implement a Heat Health Warning System (HHWS). The German HHWS is based on the ‘Perceived Temperature'. The 'Perceived Temperature' is determined through a heat budget model of the human organism which includes the main thermophysiologically relevant mechanisms of heat exchange with the atmosphere. The most important meteorological ambience parameters included in the model are air temperature, humidity, wind speed and radiation fluxes in the short-wave and long-wave ranges. In addition to using a heat budget model for the assessment of the thermal load, the German HHWS also takes into account that the human body reacts in different ways to its thermal environment due to physiological adaptation (short-term acclimatisation) and short-term behavioural adaptation. The restriction of such an approach, like the majority of approaches used to issue heat warnings, is that the threshold for a warning is generally derived from meteorological observations and that warnings are issued on the basis of weather forecasts. Both, the observed data and the weather forecasts are only available for outside conditions. The group of people who are most at risk of suffering from a heat wave, however, are the elderly and frail who mainly stay inside. The indoor situation, which varies largely from the conditions outside, is not taken into account by most of the warning systems. To overcome this limitation the DWD, in co-operation with the Fraunhofer Institute for Solar Energy Systems, has developed a model which simulates the thermal conditions in the indoor environment. As air-conditioning in private housing in Germany is not very common, the thermal indoor conditions depend on the outside conditions, on the building characteristics, and on the inhabitants' behaviour. The thermal building simulation model estimates the indoor heat load based of the predicted meteorological outside conditions by calculating the operative indoor temperature. The building types prevailing in Germany are quite heterogeneous. It was therefore decided to use for the thermal simulation a so-called "realistic worst-case” building type. In addition, a differentiation is made between two types of user behaviour: the active user opens the windows during the cold hours of the day and uses shading devices whereas the passive user does nothing to keep the heat outside. Since 2007, the DWD has been using the simulation of the indoor thermal conditions as an additional source of information for heat warnings. The information on the indoor conditions has proved very valuable for the decision whether to issue a heat warning or not.

Koppe, C.; Becker, P.; Pfafferott, J.

2009-09-01

228

Combined effects of Fenton peroxidation and CaO conditioning on sewage sludge thermal drying.  

PubMed

Joint application of Fenton's reagent and CaO can dramatically enhance sludge dewaterability, thus are also likely to affect subsequent thermal drying process. This study investigated the synergistic effects of the two conditioners on the thermal drying behavior of sewage sludge and the emission characteristics of main sulfur-/nitrogen-containing gases. According to the results, Fenton peroxidation combined with CaO conditioning efficiently promoted sludge heat transfer, reduced the amounts of both free and bound water, and created porous structure in solids to provide evaporation channels, thus producing significant positive effects on sludge drying performance. In this case, the required time for drying was shortened to one-third. Additionally, joint usage of Fenton's reagent and CaO did not increase the losses of organic matter during sludge drying process. Meanwhile, they facilitated the formation of sulfate and sulfonic acid/sulfone, leading to sulfur retention in dried sludge. Both of Fenton peroxidation and CaO conditioning promoted the oxidation, decomposition, and/or dissolution of protein and inorganic nitrogen in sludge pre-treatment. As a consequence, the emissions of sulfurous and nitrogenous gases from dewatered sludge drying were greatly suppressed. These indicate that combining Fenton peroxidation with CaO conditioning is a promising strategy to improve drying efficiency of sewage sludge and to control sulfur and nitrogen contaminants during sludge thermal drying process. PMID:25289973

Liu, Huan; Liu, Peng; Hu, Hongyun; Zhang, Qiang; Wu, Zhenyu; Yang, Jiakuan; Yao, Hong

2014-12-01

229

Supercritical carbon dioxide tubular flow under temporally varying thermal boundary condition  

SciTech Connect

During transient operation of fusion power plants the amount of thermal energy transferred from plasma to surrounding blanket modules will be varied over time, and will affect behavior of the working fluid inside the blanket and power conversion system where the coolant is in a supercritical state. Transient behavior of the power is in pulsed state in tokamak. The Optimized Supercritical Cycle Operation (OSCO) loop is constructed to investigate the thermohydraulic characteristics of the supercritical fluid under temporally varying thermal boundary condition. In this study the tube outer wall temperature data are measured for abrupt change in thermal power as a preliminary power transient test. The OSCO test conditions are selected to include the erratic behavior of the supercritical fluid under pseudo-critical condition during transient. In order to incorporate the delayed response of utilized thermocouples, a time constant is applied to adjust the obtained results. Along with the experimental study, computational fluid dynamic software is used to perform detailed analysis over the test section geometry. The preliminary test results are presented for comparison against the available correlations from the literature. (authors)

Son, H. M.; Halimi, B. [Seoul National Univ., Seoul 151-744 (Korea, Republic of); Suh, K. Y. [Seoul National Univ., Seoul 151-744 (Korea, Republic of); PHILOSOPHIA, 1 Gwanak Ro, Gwanak Gu, Seoul 151-744 (Korea, Republic of)

2012-07-01

230

Suitable features selection for monitoring thermal condition of electrical equipment using infrared thermography  

NASA Astrophysics Data System (ADS)

Monitoring the thermal condition of electrical equipment is necessary for maintaining the reliability of electrical system. The degradation of electrical equipment can cause excessive overheating, which can lead to the eventual failure of the equipment. Additionally, failure of equipment requires a lot of maintenance cost, manpower and can also be catastrophic- causing injuries or even deaths. Therefore, the recognition processof equipment conditions as normal and defective is an essential step towards maintaining reliability and stability of the system. The study introduces infrared thermography based condition monitoring of electrical equipment. Manual analysis of thermal image for detecting defects and classifying the status of equipment take a lot of time, efforts and can also lead to incorrect diagnosis results. An intelligent system that can separate the equipment automatically could help to overcome these problems. This paper discusses an intelligent classification system for the conditions of equipment using neural networks. Three sets of features namely first order histogram based statistical, grey level co-occurrence matrix and component based intensity features are extracted by image analysis, which are used as input data for the neural networks. The multilayered perceptron networks are trained using four different training algorithms namely Resilient back propagation, Bayesian Regulazation, Levenberg-Marquardt and Scale conjugate gradient. The experimental results show that the component based intensity features perform better compared to other two sets of features. Finally, after selecting the best features, multilayered perceptron network trained using Levenberg-Marquardt algorithm achieved the best results to classify the conditions of electrical equipment.

Huda, A. S. N.; Taib, S.

2013-11-01

231

Overview of Altair's Thermal Control System and the Associated Technology Development Efforts  

NASA Technical Reports Server (NTRS)

Abstract In early 2004, President Bush announced a bold vision for space exploration. One of the goals included in this vision is a return to the moon by 2020. In response to this vision, NASA established the Constellation Program, which includes several project offices. One of the Constellation projects is Altair, which is the next generation Lunar Lander. The future Altair missions are very different than the Lunar missions accomplished during the Apollo era. As such, there are several project risks and design challenges that have never before been addressed. Due to the unique thermal environment associated with this mission, many of these risks and design challenges are associated with the vehicle's thermal control system. NASA's Exploration Systems Mission Directorate (ESMD) includes the Exploration Technology Development Program (ETDP). ETDP consists of several technology development projects. The project chartered with mitigating the aforementioned risks and design challenges is the Thermal Control System Development for Exploration Project. The current paper will summarize the Altair mission profile, the operational phases, and the thermal design challenges unique to this particular vehicle. The paper will also describe the technology development efforts being performed to mitigate the risks and design challenges. The technology development project is performing a rigorous development effort that includes thermal control system fluids, evaporators, heat exchangers, and Lunar surface radiators. Constellation Program, there are several project offices. One of these projects includes the development of NASA's new lunar lander vehicle. The overall mission architecture for this vehicle, Altair, is very similar to Apollo's architecture. This paper will provide the reader with an overview of the Altair vehicle. In addition, Altair's thermal control system, including the functionality and the hardware, will be discussed. The paper will also describe the technology development process and the various technology developments currently underway.

Stephan, Ryan A.

2009-01-01

232

(Thermal energy storage technologies for heating and cooling applications)  

SciTech Connect

Recent results from selected TES research activities in Germany and Sweden under an associated IEA annex are discussed. In addition, several new technologies for heating and cooling of buildings and automobiles were reviewed and found to benefit similar efforts in the United states. Details of a meeting with Didier-Werke AG, a leading German ceramics manufacturer who will provide TES media necessary for the United States to complete field tests of an advanced high temperature latent heat storage material, are presented. Finally, an overview of the December 1990 IEA Executive Committee deliberations on TES is presented.

Tomlinson, J.J.

1990-12-19

233

Photothermal tomography of optical coatings based on surface thermal lensing technology  

NASA Astrophysics Data System (ADS)

Surface thermal lensing (STL) technology was developed into an effective apparatus for the measurement and analysis of weak-absorption optical coatings. Previous work focused on the measurement of the whole sample and was based on the assumption that the film is very thin. In this paper, by changing the modulated frequency of the pump laser from 1 Hz to 101 kHz, we accurately controlled the thermal diffusion length and got both the amplitude and phase of the photothermal signal of different samples. Based on the comparison of these signals, some analysis of 1) the thermal conductivity measurement and 2) the depth localization of strongly absorbing layer was performed.

Xu, Junhai; Zhu, Meiping; Zhao, Yuanan; Yi, Kui; Shao, Jianda

2011-12-01

234

solar thermal power systems advanced solar thermal technology project, advanced subsystems development  

NASA Technical Reports Server (NTRS)

The preliminary design for a prototype small (20 kWe) solar thermal electric generating unit was completed, consisting of several subsystems. The concentrator and the receiver collect solar energy and a thermal buffer storage with a transport system is used to provide a partially smoothed heat input to the Stirling engine. A fossil-fuel combustor is included in the receiver designs to permit operation with partial or no solar insolation (hybrid). The engine converts the heat input into mechanical action that powers a generator. To obtain electric power on a large scale, multiple solar modules will be required to operate in parallel. The small solar electric power plant used as a baseline design will provide electricity at remote sites and small communities.

1979-01-01

235

Residential photovoltaic power conditioning technology for grid connected applications  

NASA Technical Reports Server (NTRS)

Major advances in photovoltaic (PV) Power Conditioning (PC) with respect to performance and low-cost potential have been made. Solutions have been obtained to interface and control problems related to adapting available inverter designs to the grid-connected, residential photovoltaic experiments. A description is presented to contributing research and development activities. Attention is given to aspects of residential systems experience, conceptual design studies, questions of optimum topology development, and promising advanced designs for residential PV provided by development efforts of the private sector.

Key, T. S.; Klein, J. W.

1982-01-01

236

Effect of boundary conditions on the heat flux to the wall in two-temperature modeling of ‘thermal’ plasmas  

NASA Astrophysics Data System (ADS)

In this paper we propose new boundary conditions at floating and biased walls for two-temperature thermal arc models. In the derived boundary conditions the walls are assumed to be cold and therefore there is no thermionic electron emission and erosion of the wall. The boundary conditions previously used in modeling high-pressure thermal arcs ignore the formation of a plasma sheath at floating walls. As shown in the paper, using the sheath boundary conditions lead to a drastic increase in the heat flux to the wall that has to be taken into account in modeling thermal arcs and heat transfer.

Pekker, L.; Hussary, N.

2014-11-01

237

A self-packaged thermal flow sensor by CMOS MEMS technology  

Microsoft Academic Search

An integrated two-dimensional self-packaged flow sensor using CMOS MEMS technology is presented. Heater resistors formed by diffusion of boron into an n-type Si substrate are located in the center of the chip, and four poly\\/Al thermopiles for temperature sensing surround the heaters symmetrically. A trench by ICP technology between the heater and the temperature sensor was made for thermal isolation.

Dong-Hui Gao; Ming Qin; Hai-Yang Chen; Qing-An Huang

2004-01-01

238

Heart Rate Variability in Sleeping Preterm Neonates Exposed to Cool and Warm Thermal Conditions  

PubMed Central

Sudden infant death syndrome (SIDS) remains the main cause of postneonatal infant death. Thermal stress is a major risk factor and makes infants more vulnerable to SIDS. Although it has been suggested that thermal stress could lead to SIDS by disrupting autonomic functions, clinical and physiopathological data on this hypothesis are scarce. We evaluated the influence of ambient temperature on autonomic nervous activity during sleep in thirty-four preterm neonates (mean ± SD gestational age: 31.4±1.5 weeks, postmenstrual age: 36.2±0.9 weeks). Heart rate variability was assessed as a function of the sleep stage at three different ambient temperatures (thermoneutrality and warm and cool thermal conditions). An elevated ambient temperature was associated with a higher basal heart rate and lower short- and long-term variability in all sleep stages, together with higher sympathetic activity and lower parasympathetic activity. Our study results showed that modification of the ambient temperature led to significant changes in autonomic nervous system control in sleeping preterm neonates. The latter changes are very similar to those observed in infants at risk of SIDS. Our findings may provide greater insight into the thermally-induced disease mechanisms related to SIDS and may help improve prevention strategies. PMID:23840888

Stephan-Blanchard, Erwan; Chardon, Karen; Leke, Andre; Delanaud, Stephane; Bach, Veronique; Telliez, Frederic

2013-01-01

239

Conditions for thermal instability in the Galactic Centre mini-spiral region  

NASA Astrophysics Data System (ADS)

We explore the conditions for thermal instability to operate in the mini-spiral region of the Galactic Centre (Sgr A*), where both hot and cold media are known to coexist. The photoionization Cloudy calculations are performed for different physical states of plasma. We neglect the dynamics of the material and concentrate on studying the parameter ranges where thermal instability may operate, taking into account the past history of Sgr A*'s bolometric luminosity. We show that thermal instability does not operate at the present very low level of Sgr A* activity. However, Sgr A* was much more luminous in the past. For the highest luminosity states, the two-phase medium can be created up to 1.4 pc from the centre. Dust grains tend to suppress the instability, but the dust is destroyed in a strong radiation field and hot plasma. Clumpiness is thus induced in the high-activity period, and the cooling/heating timescales are long enough to preserve the past multi-phase structure. The instability enhances the clumpiness of the mini-spiral medium and creates the possibility for episodes of enhanced accretion of cold clumps towards Sgr A*. The mechanism determines the range of masses and sizes of clouds; under the conditions of Sgr A*, the likely values are 1-102 M? for the cloud's typical mass.

Ró?a?ska, A.; Czerny, B.; Kunneriath, D.; Adhikari, T. P.; Karas, V.; Mo?cibrodzka, M.

2014-12-01

240

Mathematical modelling of thermal process to aquatic environment with different hydrometeorological conditions.  

PubMed

This paper presents the mathematical model of the thermal process from thermal power plant to aquatic environment of the reservoir-cooler, which is located in the Pavlodar region, 17 Km to the north-east of Ekibastuz town. The thermal process in reservoir-cooler with different hydrometeorological conditions is considered, which is solved by three-dimensional Navier-Stokes equations and temperature equation for an incompressible flow in a stratified medium. A numerical method based on the projection method, divides the problem into three stages. At the first stage, it is assumed that the transfer of momentum occurs only by convection and diffusion. Intermediate velocity field is solved by fractional steps method. At the second stage, three-dimensional Poisson equation is solved by the Fourier method in combination with tridiagonal matrix method (Thomas algorithm). Finally, at the third stage, it is expected that the transfer is only due to the pressure gradient. Numerical method determines the basic laws of the hydrothermal processes that qualitatively and quantitatively are approximated depending on different hydrometeorological conditions. PMID:24991644

Issakhov, Alibek

2014-01-01

241

Mathematical Modelling of Thermal Process to Aquatic Environment with Different Hydrometeorological Conditions  

PubMed Central

This paper presents the mathematical model of the thermal process from thermal power plant to aquatic environment of the reservoir-cooler, which is located in the Pavlodar region, 17?Km to the north-east of Ekibastuz town. The thermal process in reservoir-cooler with different hydrometeorological conditions is considered, which is solved by three-dimensional Navier-Stokes equations and temperature equation for an incompressible flow in a stratified medium. A numerical method based on the projection method, divides the problem into three stages. At the first stage, it is assumed that the transfer of momentum occurs only by convection and diffusion. Intermediate velocity field is solved by fractional steps method. At the second stage, three-dimensional Poisson equation is solved by the Fourier method in combination with tridiagonal matrix method (Thomas algorithm). Finally, at the third stage, it is expected that the transfer is only due to the pressure gradient. Numerical method determines the basic laws of the hydrothermal processes that qualitatively and quantitatively are approximated depending on different hydrometeorological conditions. PMID:24991644

Issakhov, Alibek

2014-01-01

242

Erosion resistance of cooled thermal sprayed coatings under simulated erosion conditions at waterwall in FBCs  

SciTech Connect

The erosion-corrosion (E-C) behavior of cooled 1018 steel and several thermal sprayed coatings by bed ash, retrieved from an operating circulating fluidized bed combustor (CFBC) boiler firing biomass, was determined in laboratory tests using a nozzle type elevated temperature erosion tester. Test conditions attempted but not exactly to simulate the erosion conditions found at the refractory/bare-tube interface at the combustor waterwall of FBC boilers. The specimens were water-cooled on the backside. Material wastage rates were determined from the thickness loss measurements of specimens. Test results were compared with erosion-corrosion test results for isothermal specimens. The morphology of specimens was examined by scanning electron microscopy (SEM). It was found that the cooled specimens demonstrated higher erosion-corrosion wastage than those of the isothermal specimens. At a shallow impact angle of 30{degree} the effect of cooling specimens on the erosion wastage for thermal sprayed coatings was less than that for 1018 steel, while at a steep impact angle of 90{degree} this effect for thermal sprayed coatings was greater than that for 1018 steel. The hypersonic velocity oxygen fuel (HVOF) Cr{sub 3}C{sub 2} ceramic coating exhibited the highest E-C resistance due to its favorable composition and fine structure. The poor E-C resistance of arc-sprayed FeCrSiB coating was attributed to larger splat size, higher porosity and the presence of radial and tangential microcracks within the coating.

Wang, B.Q. [Metalspray USA, Inc., Richmond, VA (United States). Metallurgical Lab.; Lee, S.W. [Morgan State Univ., Baltimore, MD (United States). School of Engineering

1997-12-31

243

Diurnal cool thermal energy storage: Research programs, technological developments, and commercial status  

NASA Astrophysics Data System (ADS)

This report presents an overview of the major federal and private research and development efforts in diurnal cool thermal energy storage for electric load management in buildings. Included are brief technical descriptions and research histories of the technologies and applications of cool thermal storage. The goals, accomplishments, and funding levels of major thermal storage research programs also are summarized. The report concludes with the results of recent field performance evaluations of cool thermal storage installations and a discussion of the current commercial status of thermal storage equipment, including utility participation programs. This report was sponsored by the Technology and Consumer Products (TCP) Division within the Office of Conservation of the U.S. Department of Energy. This report is part of TCP's ongoing effort to examine and evaluate technology developments and research efforts in the areas of lighting, space heating and cooling, water heating, refrigeration, and other building energy conversion equipment. Information obtained through this effort is used as an input in developing the U.S. research agenda in these areas.

Wise, M. A.

1992-01-01

244

Thermal Analysis Of The NASA Integrated Vehicle Health Monitoring Experiment Technology For X-Vehicles (NITEX)  

NASA Technical Reports Server (NTRS)

The purpose of this project was to perform a thermal analysis for the NASA Integrated Vehicle Health Monitoring (IVHM) Technology Experiment for X-vehicles (NITEX). This electronics package monitors vehicle sensor information in flight and downlinks vehicle health summary information via telemetry. The experiment will be tested on the X-34 in an unpressurized compartment, in the vicinity of one of the vehicle's liquid oxygen tanks. The transient temperature profile for the electronics package has been determined using finite element analysis for possible mission profiles that will most likely expose the package to the most extreme hot and cold environmental conditions. From the analyses, it was determined that temperature limits for the electronics would be exceeded for the worst case cold environment mission profile. The finite element model used for the analyses was modified to examine the use of insulation to address this problem. Recommendations for insulating the experiment for the cold environment are presented, and were analyzed to determine their effect on a nominal mission profile.

Hegab, Hisham E.

2001-01-01

245

Area Optimization for Leakage Reduction and Thermal Stability in Nanometer-Scale Technologies  

Microsoft Academic Search

Traditionally, the minimum possible area of a very large scale integration (VLSI) layout is considered to be the best for delay and power minimization due to decreased interconnect capacitance. This paper, however, shows that the use of minimum area does not result in minimum power and\\/or delay in nanometer-scale technologies due to thermal effects and, in some cases, may cause

Ja Chun Ku; Yehea I. Ismail

2008-01-01

246

Heavy oil reservoirs recoverable by thermal technology. Annual report  

SciTech Connect

The purpose of this study was to compile data on reservoirs that contain heavy oil in the 8 to 25/sup 0/ API gravity range, contain at least ten million barrels of oil currently in place, and are non-carbonate in lithology. The reservoirs within these constraints were then analyzed in light of applicable recovery technology, either steam-drive or in situ combustion, and then ranked hierarchically as candidate reservoirs. The study is presented in three volumes. Volume I presents the project background and approach, the screening analysis, ranking criteria, and listing of candidate reservoirs. The economic and environmental aspects of heavy oil recovery are included in appendices to this volume. This study provides an extensive basis for heavy oil development, but should be extended to include carbonate reservoirs and tar sands. It is imperative to look at heavy oil reservoirs and projects on an individual basis; it was discovered that operators, and industrial and government analysts will lump heavy oil reservoirs as poor producers, however, it was found that upon detailed analysis, a large number, so categorized, were producing very well. A study also should be conducted on abandoned reservoirs. To utilize heavy oil, refiners will have to add various unit operations to their processes, such as hydrotreaters and hydrodesulfurizers and will require, in most cases, a lighter blending stock. A big problem in producing heavy oil is that of regulation; specifically, it was found that the regulatory constraints are so fluid and changing that one cannot settle on a favorable recovery and production plan with enough confidence in the regulatory requirements to commit capital to the project.

Kujawa, P.

1981-02-01

247

Thermalization, Isotropization and Elliptic Flow from Nonequilibrium Initial Conditions with a Saturation Scale  

E-print Network

In this article we report on our results about the computation of the elliptic flow of the quark-gluon-plasma produced in relativistic heavy ion collisions, simulating the expansion of the fireball by solving the relativistic Boltzmann equation for the parton distribution function tuned at a fixed shear viscosity to entropy density ratio $\\eta/s$. Our main goal is to put emphasis on the role of a saturation scale in the initial gluon spectrum, which makes the initial distribution far from a thermalized one. We find that the presence of the saturation scale reduces the efficiency in building-up the elliptic flow, even if the thermalization process is quite fast $\\tau_{therm} \\approx 0.8 \\,\\rm fm/c$ and the pressure isotropization even faster $\\tau_{isotr} \\approx 0.3 \\,\\rm fm/c$. The impact of the non-equilibrium implied by the saturation scale manifests for non-central collisions and can modify the estimate of the viscosity respect to the assumption of full thermalization in $p_T$-space. We find that the estimate of $\\eta/s$ is modified from $\\eta/s \\approx 2/4\\pi$ to $\\eta/s \\approx 1/4\\pi$ at RHIC and from $\\eta/s \\approx 3/4\\pi$ to $\\eta/s \\approx 2/4\\pi$ at LHC. We complete our investigation by a study of the thermalization and isotropization times of the fireball for different initial conditions and values of $\\eta/s$ showing how the latter affects both isotropization and thermalization. Lastly, we have seen that the range of values explored by the phase-space distribution function $f$ is such that at $p_T<0.5\\, \\rm GeV$ the inner part of the fireball stays with occupation number significantly larger than unity despite the fast longitudinal expansion, which might suggest the possibility of the formation of a transient Bose-Einstein Condensate.

Marco Ruggieri; Francesco Scardina; Salvatore Plumari; Vincenzo Greco

2013-12-20

248

Thermalization, isotropization, and elliptic flow from nonequilibrium initial conditions with a saturation scale  

NASA Astrophysics Data System (ADS)

In this article we report on our results about the computation of the elliptic flow of the quark-gluon plasma produced in relativistic heavy-ion collisions, simulating the expansion of the fireball by solving the relativistic Boltzmann equation for the parton distribution function tuned at a fixed shear-viscosity to entropy-density ratio ? /s. Our main goal is to put emphasis on the role of a saturation scale in the initial gluon spectrum, which makes the initial distribution far from a thermalized one. We find that the presence of the saturation scale reduces the efficiency in building up the elliptic flow, even if the thermalization process is quite fast ?therm?0.8fm/c and the pressure isotropization is even faster ?isotr?0.5fm/c. The impact of the nonequilibrium implied by the saturation scale manifests for noncentral collisions and can modify the estimate of the viscosity with respect to the assumption of full thermalization in pT space. We find that the estimate of ? /s is modified from ? /s?2/4? to ? /s?1/4? at the Relativistic Heavy-Ion Collider and from ? /s?3/4? to ? /s?2/4? at the Large Hadron Collider. We complete our investigation with a study of the thermalization and isotropization times of the fireball for different initial conditions and values of ? /s showing how the latter affects both isotropization and thermalization. Last, we have seen that the range of values explored by the phase-space distribution function f is such that at pT<0.5GeV the inner part of the fireball stays with occupation number significantly larger than unity despite the fast longitudinal expansion, which might suggest the possibility of the formation of a transient Bose-Einstein condensate.

Ruggieri, M.; Scardina, F.; Plumari, S.; Greco, V.

2014-05-01

249

Nuclear Thermal Propulsion Technology - Summary of FY 1991 Interagency Panel Planning  

NASA Technical Reports Server (NTRS)

An Interagency (NASA/DOE/DOD) technical panel has been working in 1991 to evaluate nuclear thermal propulsion (NTP) concepts on a consistent basis, and to continue technology development project planning for a joint project in nuclear propulsion for Space Exploration Initiative (SEI). This paper summarizes the efforts of the panel to date and summarizes the technology plans defined for NTP. Concepts were categorized based on probable technology readiness data, and innovative 'proof-of-concept' tests and analyses were defined. While further studies will be required to provide a consistent comparison of all of the NTP concepts, the current status of the studies is presented.

Clark, John S.; Mcdaniel, Patrick; Howe, Steven; Stanley, Marland

1991-01-01

250

Modeling of Thermal Performance of Multiphase Nuclear Fuel Cell Under Variable Gravity Conditions  

NASA Technical Reports Server (NTRS)

A unique numerical method has been developed to model the dynamic processes of bulk evaporation and condensation processes, associated with internal heat generation and natural convection under different gravity levels. The internal energy formulation, for the bulk liquid-vapor phase change problems in an encapsulated container, was employed. The equations, governing the conservation of mass, momentum and energy for both phases involved in phase change, were solved. The thermal performance of a multiphase uranium tetra-fluoride fuel element under zero gravity, micro-gravity and normal gravity conditions has been investigated. The modeling yielded results including the evolution of the bulk liquid-vapor phase change process, the evolution of the liquid-vapor interface, the formation and development of the liquid film covering the side wall surface, the temperature distribution and the convection flow field in the fuel element. The strong dependence of the thermal performance of such multiphase nuclear fuel cell on the gravity condition has been revealed. Under all three gravity conditions, 0-g, 10(exp -3)-g, and 1-g, the liquid film is formed and covers the entire side wall. The liquid film covering the side wall is more isothermalized at the wall surface, which can prevent the side wall from being over-heated. As the gravity increases, the liquid film is thinner, the temperature gradient is larger across the liquid film and smaller across the vapor phase. This investigation provides valuable information about the thermal performance of multi-phase nuclear fuel element for the potential space and ground applications.

Ding, Z.; Anghaie, S.

1996-01-01

251

Role of atomic vacancies and boundary conditions on ballistic thermal transport in graphene nanoribbons  

NASA Astrophysics Data System (ADS)

Quantum thermal transport in armchair and zigzag graphene nanoribbons is investigated in the presence of single atomic vacancies and subject to different boundary conditions. We start with a full comparison of the phonon polarizations and energy dispersions as given by a fifth-nearest-neighbor force-constant model (5NNFCM) and by elasticity theory of continuum membranes (ETCM). For free-edge ribbons, we discuss the behavior of an additional acoustic edge-localized flexural mode, known as fourth acoustic branch (4ZA), which has a small gap when it is obtained by the 5NNFCM. Then, we show that ribbons with supported edges have a sample-size dependent energy gap in the phonon spectrum which is particularly large for in-plane modes. Irrespective to the calculation method and the boundary condition, the dependence of the energy gap for the low-energy optical phonon modes against the ribbon width W is found to be proportional to 1/W for in-plane, and 1/W2 for out-of-plane phonon modes. Using the 5NNFCM, the ballistic thermal conductance and its contributions from every single phonon mode are then obtained by the nonequilibrium Green's function technique. We found that, while edge and central localized single atomic vacancies do not affect the low-energy transmission function of in-plane phonon modes, they reduce considerably the contributions of the flexural modes. On the other hand, in-plane modes contributions are strongly dependent on the boundary conditions and at low temperatures can be highly reduced in supported-edge samples. These findings could open a route to engineer graphene based devices where it is possible to discriminate the relative contribution of polarized phonons and to tune the thermal transport on the nanoscale.

Scuracchio, P.; Costamagna, S.; Peeters, F. M.; Dobry, A.

2014-07-01

252

Human thermal bioclimatic conditions associated with acute cardiovascular syndromes in Crete Island, Greece  

NASA Astrophysics Data System (ADS)

The aim of this study is to quantify the association between bioclimatic conditions and daily counts of admissions for non-fatal acute cardiovascular (acute coronary syndrome, arrhythmia, decompensation of heart failure) syndromes (ACS) registered by the two main hospitals in Heraklion, Crete Island, during a five-year period 2008-2012. The bioclimatic conditions analyzed are based on human thermal bioclimatic indices such as the Physiological Equivalent Temperature (PET) and the Universal Thermal Climate Index (UTCI). Mean daily meteorological parameters, such as air temperature, relative humidity, wind speed and cloudiness, were acquired from the meteorological station of Heraklion (Hellenic National Meteorological Service). These parameters were used as input variables in modeling the aforementioned thermal indices, in order to interpret the grade of the thermo-physiological stress. The PET and UTCI analysis was performed by the use of the radiation and bioclimate model, "RayMan", which is well-suited to calculate radiation fluxes and human biometeorological indices. Generalized linear models (GLM) were applied to time series of daily numbers of outpatients with ACS against bioclimatic variations, after controlling for possible confounders and adjustment for season and trends. The interpretation of the results of this analysis suggests a significant association between cold weather and increased coronary heart disease incidence, especially in the elderly and males. Additionally, heat stress plays an important role in the configuration of daily ACS outpatients, even in temperate climate, as that in Crete Island. In this point it is worth mentioning that Crete Island is frequently affected by Saharan outbreaks, which are associated in many cases with miscellaneous phenomena, such as Föhn winds - hot and dry winds - causing extreme bioclimatic conditions (strong heat stress). Taking into consideration the projected increased ambient temperature in the future, ACS exacerbation is very likely to happen during the warm period, against mitigation during the cold period of the year.

Bleta, Anastasia G.; Nastos, Panagiotis T.

2013-04-01

253

The optimum levels of the thermal protection of residential buildings under climatic conditions of Russia  

NASA Astrophysics Data System (ADS)

The present paper reports the results of determining the optimum values of the resistance of building envelopes to heat transfer for both existing and newly constructed buildings for regions of Russia with different climatic conditions. An analysis for the sensitivity of obtained optimum solutions to changes in external factors has been made. The potential of energy saving in both the existing housing stock and in newly constructed buildings due to the improvement of thermal protection performance of buildings to the optimum level has been determined.

Filippov, S. P.; Dil'man, M. D.; Ionov, M. S.

2013-11-01

254

Computer Modeling of Flow, Thermal Condition and Ash Deposition in a Hot-Gas Filtration Device  

SciTech Connect

The objective of the present study is to develop a computational model for simulating the gas flow, thermal condition and ash transport and deposition pattern in the hot-gas filtration systems. The computational model is to provide a virtual tool for design and operation modifications. Particular attention is given to the Particle Control Device (PCD) at the Power Systems Development Facility (PSDF) in Wilsonville, Alabama. For evaluation of gas velocity and temperature field in the vessel, the FLUENT commercial CFD computer code is used. Ash particle transport and deposition pattern was analyzed with the Lagrangian particle tracking approach.

Ahmadi, G.; Mazaheri, A.; Liu, C.; Gamwo, I.K.

2002-09-19

255

Hypothetical accident condition thermal analysis and testing of a Type B drum package  

SciTech Connect

A thermophysical property model developed to analytically determine the thermal response of cane fiberboard when exposed to temperatures and heat fluxes associated with the 10 CFR 71 hypothetical accident condition (HAC) has been benchmarked against two Type B drum package fire test results. The model 9973 package was fire tested after a 30 ft. top down drop and puncture, and an undamaged model 9975 package containing a heater (21W) was fire tested to determine content heat source effects. Analysis results using a refined version of a previously developed HAC fiberboard model compared well against the test data from both the 9973 and 9975 packages.

Hensel, S.J.; Alstine, M.N. Van; Gromada, R.J.

1995-07-01

256

Thermal Analysis of the Advanced Technology Large Aperture Space Telescope (ATLAST) 8 Meter Primary Mirror  

NASA Technical Reports Server (NTRS)

The Advanced Technology Large Aperture Space Telescope (ATLAST) preliminary design concept consists of an 8 meter diameter monolithic primary mirror enclosed in an insulated, optical tube with stray light baffles and a sunshade. ATLAST will be placed in orbit about the Sun-Earth L2 and will experience constant exposure to the sun. The insulation on the optical tube and sunshade serve to cold bias the telescope which helps to minimize thermal gradients. The primary mirror will be maintained at 280K with an active thermal control system. The geometric model of the primary mirror, optical tube, sun baffles, and sunshade was developed using Thermal Desktop(R) SINDA/FLUINT(R) was used for the thermal analysis and the radiation environment was analyzed using RADCAD(R). A XX node model was executed in order to characterize the static performance and thermal stability of the mirror during maneuvers. This is important because long exposure observations, such as extra-solar terrestrial planet finding and characterization, require a very stable observatory wave front. Steady state thermal analyses served to predict mirror temperatures for several different sun angles. Transient analyses were performed in order to predict thermal time constant of the primary mirror for a 20 degree slew or 30 degree roll maneuver. This paper describes the thermal model and provides details of the geometry, thermo-optical properties, and the environment which influences the thermal performance. All assumptions that were used in the analysis are also documented. Parametric analyses are summarized for design parameters including primary mirror coatings and sunshade configuration. Estimates of mirror heater power requirements are reported. The thermal model demonstrates results for the primary mirror heated from the back side and edges using a heater system with multiple independently controlled zones.

Hornsby, Linda; Stahl, H. Philip; Hopkins, Randall C.

2010-01-01

257

Fusion Engineering and Design 81 (2006) 11311144 Physics and technology conditions for attaining tritium  

E-print Network

Fusion Engineering and Design 81 (2006) 1131­1144 Physics and technology conditions for attaining tritium self-sufficiency for the DT fuel cycle M.E. Sawana,, M.A. Abdoub a Fusion Technology Institute than the required TBR. The potential of achieving tritium self-sufficiency depends on many system

Abdou, Mohamed

258

Fast access to the CMS detector condition data employing HTML5 technologies  

Microsoft Academic Search

This paper focuses on using HTML version 5 (HTML5) for accessing condition data for the CMS experiment, evaluating the benefits and risks posed by the use of this technology. According to the authors of HTML5, this technology attempts to solve issues found in previous iterations of HTML and addresses the needs of web applications, an area previously not adequately covered

Giuseppe Antonio Pierro; Francesca Cavallari; Salvatore Di Guida; Vincenzo Innocente

2011-01-01

259

Indoor air quality and thermal comfort studies of an under-floor air-conditioning system in the tropics  

Microsoft Academic Search

This paper reports thermal comfort and indoor air quality (IAQ) studies of an under-floor air-conditioning (UFAC) system in hot and humid climate. Thermal comfort parameters were measured at predetermined grid points within an imaginary plane to predict the airflow pattern of the supply air jet as well as to determine the occurrence of thermal stratification in the office space. Fanger’s

S. C. Sekhar; C. S. Ching

2002-01-01

260

Improving thermal conductivity of Sm 2O 3-doped AlN ceramics by changing sintering conditions  

Microsoft Academic Search

The effects of sintering conditions including soaking time and packing powder on the thermal conductivity of Aluminum nitride (AlN) ceramics with Sm2O3 additives were investigated. The thermal conductivity values of AlN ceramics sintered were improved after increasing soaking time, but not considerably due to the interconnected secondary phases. While the specimen sintered without packing powder showed much higher thermal conductivity

Xinrui Xu; Hanrui Zhuang; Wenlan Li; Suying Xu; Baolin Zhang; Xiren Fu

2003-01-01

261

Genotypic Influence on Aversive Conditioning in Honeybees, Using a Novel Thermal Reinforcement Procedure  

PubMed Central

In Pavlovian conditioning, animals learn to associate initially neutral stimuli with positive or negative outcomes, leading to appetitive and aversive learning respectively. The honeybee (Apis mellifera) is a prominent invertebrate model for studying both versions of olfactory learning and for unraveling the influence of genotype. As a queen bee mates with about 15 males, her worker offspring belong to as many, genetically-different patrilines. While the genetic dependency of appetitive learning is well established in bees, it is not the case for aversive learning, as a robust protocol was only developed recently. In the original conditioning of the sting extension response (SER), bees learn to associate an odor (conditioned stimulus - CS) with an electric shock (unconditioned stimulus - US). This US is however not a natural stimulus for bees, which may represent a potential caveat for dissecting the genetics underlying aversive learning. We thus first tested heat as a potential new US for SER conditioning. We show that thermal stimulation of several sensory structures on the bee’s body triggers the SER, in a temperature-dependent manner. Moreover, heat applied to the antennae, mouthparts or legs is an efficient US for SER conditioning. Then, using microsatellite analysis, we analyzed heat sensitivity and aversive learning performances in ten worker patrilines issued from a naturally inseminated queen. We demonstrate a strong influence of genotype on aversive learning, possibly indicating the existence of a genetic determinism of this capacity. Such determinism could be instrumental for efficient task partitioning within the hive. PMID:24828422

Junca, Pierre; Carcaud, Julie; Moulin, Sibyle; Garnery, Lionel; Sandoz, Jean-Christophe

2014-01-01

262

Conditions for the Thermal Instability in the Galactic Centre Mini-spiral region  

E-print Network

We explore the conditions for the thermal instability to operate in the mini-spiral region of the Galactic centre (Sgr A*), where both the hot and cold media are known to coexist. The photoionisation Cloudy calculations are performed for different physical states of plasma. We neglect the dynamics of the material and concentrate on the study of the parameter ranges where the thermal instability may operate, taking into account the past history of Sgr A* bolometric luminosity. We show that the thermal instability does not operate at the present very low level of the Sgr A* activity. However, Sgr A* was much more luminous in the past. For the highest luminosity states the two-phase medium can be created up to 1.4 pc from the centre. The presence of dust grains tends to suppress the instability, but the dust is destroyed in the presence of strong radiation field and hot plasma. The clumpiness is thus induced in the high activity period, and the cooling/heating timescales are long enough to preserve later the pas...

Ró?a?ska, A; Kunneriath, D; Adhikari, T P; Karas, V; Mo?cibirodzka, M

2014-01-01

263

Three-Dimensional Mixed Convection Flow of Viscoelastic Fluid with Thermal Radiation and Convective Conditions  

PubMed Central

The objective of present research is to examine the thermal radiation effect in three-dimensional mixed convection flow of viscoelastic fluid. The boundary layer analysis has been discussed for flow by an exponentially stretching surface with convective conditions. The resulting partial differential equations are reduced into a system of nonlinear ordinary differential equations using appropriate transformations. The series solutions are developed through a modern technique known as the homotopy analysis method. The convergent expressions of velocity components and temperature are derived. The solutions obtained are dependent on seven sundry parameters including the viscoelastic parameter, mixed convection parameter, ratio parameter, temperature exponent, Prandtl number, Biot number and radiation parameter. A systematic study is performed to analyze the impacts of these influential parameters on the velocity and temperature, the skin friction coefficients and the local Nusselt number. It is observed that mixed convection parameter in momentum and thermal boundary layers has opposite role. Thermal boundary layer is found to decrease when ratio parameter, Prandtl number and temperature exponent are increased. Local Nusselt number is increasing function of viscoelastic parameter and Biot number. Radiation parameter on the Nusselt number has opposite effects when compared with viscoelastic parameter. PMID:24608594

Hayat, Tasawar; Ashraf, Muhammad Bilal; Alsulami, Hamed H.; Alhuthali, Muhammad Shahab

2014-01-01

264

Hypothetical accident conditions, free drop and thermal tests: Specification 6M  

SciTech Connect

The 30 gallon Specification 6M shipping container with rolled-top food pack cans as inner containers is evaluated under conditions required by 10 CFR 71.42. One kilogram of depleted uranium as UO/sub 2/ was packaged in each of the inner containers. After completion of a free drop test and a simulated thermal test, the maximum observed leakage of UO/sub 2/ for the following week was 3.2 ..mu..g. This leakage is well below the allowable leakage per week for most plutonium isotopic mixtures. Using the examples provided, any plutonium isotopic mixture can be easily compared with the allowable leakage per week. Test conditions and results are reported.

Blankenship, R.W.

1980-05-01

265

A novel underground solar thermal heat storage unit cum heat exchanger for non air-conditioned buildings  

Microsoft Academic Search

A novel passive space conditioning configuration is presented, integrating a Solar Collector System, Underground Storage Tank and Novel Heat Exchanger. This Underground Solar Thermal Heat Exchanger (USTHE) provided improved sensible heating\\/cooling of air by employing a Novel Heat Exchanger (NHX). The dynamic performance of the storage tank in USTHE is modelled using the finite difference method accounting thermal stratification of

Rakesh Kumar; S. C. Kaushik

2003-01-01

266

Limiting factors to advancing thermal-battery technology for naval applications  

SciTech Connect

Thermal batteries are primary reserve electrochemical power sources using molten salt electrolyte which experience little effective aging while in storage or dormant deployment. Thermal batteries are primarily used in military applications, and are currently used in a wide variety of Navy devices such as missiles, torpedoes, decays, and training targets, usually as power supplies in guidance, propulsion, and Safe/Arm applications. Technology developments have increased the available energy and power density ratings by an order of magnitude in the last ten years. Present thermal batteries, using lithium anodes and metal sulfide cathodes, are capable of performing applications where only less rugged and more expensive silver oxide/zinc or silver/magnesium chloride seawater batteries could serve previously. Additionally, these batteries are capable of supplanting lithium/thionyl chloride reserve batteries in a variety of specifically optimized designs. Increases in thermal battery energy and power density capabilities are not projected to continue with the current available technology. Several battery designs are now at the edge of feasibility and safety. Since future naval systems are likely to require continued growth of battery energy and Power densities, there must be significant advances in battery technology. Specifically, anode alloy composition and new cathode materials must be investigated to allow for safe development and deployment of these high power, higher energy density batteries.

Davis, P.B.; Winchester, C.S.

1991-10-01

267

Design, technology, and application of integrated piezoresistive scanning thermal microscopy (SThM) microcantilever  

NASA Astrophysics Data System (ADS)

In this article we describe a novel piezoresistive cantilever technology The described cantilever can be also applied in the investigations of the thermal surface properties in all Scanning Thermal Microscopy (SThM) techniques. Batch lithography/etch patterning process combined with focused ion beam (FIB) modification allows to manufacture thermally active, resistive tips with a nanometer radius of curvature. This design makes the proposed nanoprobes especially attractive for their application in the measurement of the thermal behavior of micro- and nanoelectronic devices. Developed microcantilever is equipped with piezoresistive deflection sensor. The proposed architecture of the cantilever probe enables easy its easy integration with micro- and nanomanipulators and scanning electron microscopes.In order to approach very precisely the microcantilever near to the location to be characterized, it is mounted on a compact nanomanipulator based on a novel mobile technology. This technology allows very stable positioning, with a nanometric resolution over several centimeters which is for example useful for large samples investigations. Moreover, thanks to the vacuum-compatibility, the experiments can be carried out inside scanning electron microscopes.

Janus, Pawe?; Grabiec, Piotr; Sierakowski, Andrzej; Gotszalk, Teodor; Rudek, Maciej; Kopiec, Daniel; Majstrzyk, Wojciech; Boetsch, Guillaume; Koehler, Bernd

2014-09-01

268

Thermal Comfort under Transient Metabolic and Dynamic Localized Airflow Conditions Combined with Neutral and Warm Ambient Temperatures  

E-print Network

, in practice, people move between spaces, and thermal conditions such as metabolic rate, surface temperatures, airflow speed and direction vary in a typical day. A human subject test was designed to determine the transient relationship between the people...

Ugursal, Ahmet

2012-02-14

269

Numerical simulation of the thermal conditions in a sea bay water area used for water supply to nuclear power plants  

SciTech Connect

Consideration is given to the numerical simulation of the thermal conditions in sea water areas used for both water supply to and dissipation of low-grade heat from a nuclear power plant on the shore of a sea bay.

Sokolov, A. S. [JSC 'B. E. Vedeneev All-Russia Research Institute of Hydraulic Engineering (VNIIG)' (Russian Federation)] [JSC 'B. E. Vedeneev All-Russia Research Institute of Hydraulic Engineering (VNIIG)' (Russian Federation)

2013-07-15

270

Reply to the Comment on "Optimal working conditions for thermoelectric generators with realistic thermal coupling" by S. Su et al  

E-print Network

We reply to the comment made by Su et al. on "Optimal working conditions for thermoelectric generators with realistic thermal coupling". In particular we justify the efficiency definition used in the main paper.

Apertet, Y; Glavatskaya, O; Goupil, C; Lecoeur, P; 10.1209/0295-5075/101/68008

2013-01-01

271

Influence of thermal challenge on conditioned feeding forays of juvenile rainbow trout  

SciTech Connect

Juvenile rainbow trout (Salmo gairdneri) conditioned to traverse a 2.4-m-long channel to receive a food reward were subjected to in-transit thermal challenges. Conditioning was to a criterion that required 80% of the fish to leave the home area and reach the reward area within 2 minutes of release. Challenges were at successive 3 C increments above acclimation or the previous challenge temperature. Fish were first observed to delay their entrance into the intervening heated water at challenge temperatures of 12 to 15 C above acclimation. At each increment above 12 to 15 C over acclimation temperature, delay in transit increased; however, complete group inhibition was never achieved. Above their critical thermal maximum (CTM) the reward was achieved even at the expense of deaths among the achievers. Responses were the same whether fish were challenged individually or as groups. Fish exposed to their CTM without prior challenges at less stressful temperatures responded similarly to those receiving progressively greater challenges.

Munson, B.H.; McCormick, J.H.; Collins, H.L.

1980-01-01

272

Behavioural Responses to Thermal Conditions Affect Seasonal Mass Change in a Heat-Sensitive Northern Ungulate  

PubMed Central

Background Empirical tests that link temperature-mediated changes in behaviour (activity and resource selection) to individual fitness or condition are currently lacking for endotherms yet may be critical to understanding the effect of climate change on population dynamics. Moose (Alces alces) are thought to suffer from heat stress in all seasons so provide a good biological model to test whether exposure to non-optimal ambient temperatures influence seasonal changes in body mass. Seasonal mass change is an important fitness correlate of large herbivores and affects reproductive success of female moose. Methodology/Principal Findings Using GPS-collared adult female moose from two populations in southern Norway we quantified individual differences in seasonal activity budget and resource selection patterns as a function of seasonal temperatures thought to induce heat stress in moose. Individual body mass was recorded in early and late winter, and autumn to calculate seasonal mass changes (n?=?52 over winter, n?=?47 over summer). We found large individual differences in temperature-dependent resource selection patterns as well as within and between season variability in thermoregulatory strategies. As expected, individuals using an optimal strategy, selecting young successional forest (foraging habitat) at low ambient temperatures and mature coniferous forest (thermal shelter) during thermally stressful conditions, lost less mass in winter and gained more mass in summer. Conclusions/Significance This study provides evidence that behavioural responses to temperature have important consequences for seasonal mass change in moose living in the south of their distribution in Norway, and may be a contributing factor to recently observed declines in moose demographic performance. Although the mechanisms that underlie the observed temperature mediated habitat-fitness relationship remain to be tested, physiological state and individual variation in thermal tolerance are likely contributory factors. Climate-related effects on animal behaviour, and subsequently fitness, are expected to intensify as global warming continues. PMID:23776584

van Beest, Floris M.; Milner, Jos M.

2013-01-01

273

Effects of service condition on rolling contact fatigue failure mechanism and lifetime of thermal spray coatings—A review  

NASA Astrophysics Data System (ADS)

The service condition determines the Rolling Contact Fatigue(RCF) failure mechanism and lifetime under ascertain material structure integrity parameter of thermal spray coating. The available literature on the RCF testing of thermal spray coatings under various condition services is considerable; it is generally difficult to synthesize all of the result to obtain a comprehensive understanding of the parameters which has a great effect on a thermal spray coating's resistance of RCF. The effects of service conditions(lubrication states, contact stresses, revolve speed, and slip ratio) on the changing of thermal spray coatings' contact fatigue lifetime is introduced systematically. The effects of different service condition on RCF failure mechanism of thermal spray coating from the change of material structure integrity are also summarized. Moreover, In order to enhance the RCF performance, the parameter optimal design formula of service condition and material structure integrity is proposed based on the effect of service condition on thermal spray coatings' contact fatigue lifetime and RCF failure mechanism. The shortage of available literature and the forecast focus in future researches are discussed based on available research. The explicit result of RCF lifetime law and parameter optimal design formula in term of lubrication states, contact stresses, revolve speed, and slip ratio, is significant to improve the RCF performance on the engineering application.

Cui, Huawei; Cui, Xiufang; Wang, Haidou; Xing, Zhiguo; Jin, Guo

2014-10-01

274

NREL's Energy-Saving Technology for Air Conditioning Cuts Peak Power Loads Without Using Harmful Refrigerants (Fact Sheet)  

SciTech Connect

This fact sheet describes how the DEVAP air conditioner was invented, explains how the technology works, and why it won an R&D 100 Award. Desiccant-enhanced evaporative (DEVAP) air-conditioning will provide superior comfort for commercial buildings in any climate at a small fraction of the electricity costs of conventional air-conditioning equipment, releasing far less carbon dioxide and cutting costly peak electrical demand by an estimated 80%. Air conditioning currently consumes about 15% of the electricity generated in the United States and is a major contributor to peak electrical demand on hot summer days, which can lead to escalating power costs, brownouts, and rolling blackouts. DEVAP employs an innovative combination of air-cooling technologies to reduce energy use by up to 81%. DEVAP also shifts most of the energy needs to thermal energy sources, reducing annual electricity use by up to 90%. In doing so, DEVAP is estimated to cut peak electrical demand by nearly 80% in all climates. Widespread use of this cooling cycle would dramatically cut peak electrical loads throughout the country, saving billions of dollars in investments and operating costs for our nation's electrical utilities. Water is already used as a refrigerant in evaporative coolers, a common and widely used energy-saving technology for arid regions. The technology cools incoming hot, dry air by evaporating water into it. The energy absorbed by the water as it evaporates, known as the latent heat of vaporization, cools the air while humidifying it. However, evaporative coolers only function when the air is dry, and they deliver humid air that can lower the comfort level for building occupants. And even many dry climates like Phoenix, Arizona, have a humid season when evaporative cooling won't work well. DEVAP extends the applicability of evaporative cooling by first using a liquid desiccant-a water-absorbing material-to dry the air. The dry air is then passed to an indirect evaporative cooling stage, in which the incoming air is in thermal contact with a moistened surface that evaporates the water into a separate air stream. As the evaporation cools the moistened surface, it draws heat from the incoming air without adding humidity to it. A number of cooling cycles have been developed that employ indirect evaporative cooling, but DEVAP achieves a superior efficiency relative to its technological siblings.

Not Available

2012-07-01

275

A long-term strategic plan for development of solar thermal electric technology  

SciTech Connect

Solar thermal electric (STE) technologies--parabolic troughs, power towers, and dish/engine systems--can convert sunlight into electricity efficiently and with minimum effect on the environment. These technologies currently range from developmental to early commercial stages of maturity. This paper summarizes the results of a recent strategic planning effort conducted by the US Department of Energy (DOE) to develop a long-term strategy for the development of STE technologies (DOE, 1996). The planning team led by DOE included representatives from the solar thermal industry, domestic utilities, state energy offices, and Sun-Lab (the cooperative Sandia National Laboratories/National Renewable Energy Laboratory partnership that supports the STE Program) as well as project developers. The plan was aimed at identifying specific activities necessary to achieve the DOE vision of 20 gigawatts of installed STE capacity by the year 2020. The planning team developed five strategies that both build on the strengths of, and opportunities for, STE technology and address weaknesses and threats. These strategies are to support future commercial opportunities for STE technologies; demonstrate improved performance and reliability of STE components and systems; reduce STE energy costs; develop advanced STE systems and applications; and address nontechnical barriers and champion STE power. The details of each of these strategies are discussed.

Williams, T.A. [National Renewable Energy Lab., Golden, CO (United States); Burch, G.D. [Dept. of Energy, Washington, DC (United States); Chavez, J.M.; Mancini, T.R.; Tyner, C.E. [Sandia National Labs., Albuquerque, NM (United States)

1997-06-01

276

Thermal power systems, point-focusing distributed receiver technology project. Volume 2: Detailed report  

NASA Technical Reports Server (NTRS)

Thermal or electrical power from the sun's radiated energy through Point-Focusing Distributed Receiver technology is the goal of this Project. The energy thus produced must be economically competitive with other sources. The Project supports the industrial development of technology and hardware for extracting energy from solar power to achieve the stated goal. Present studies are working to concentrate the solar energy through mirrors or lenses, to a working fluid or gas, and through a power converter change to an energy source useful to man. Rankine-cycle and Brayton-cycle engines are currently being developed as the most promising energy converters for our near future needs.

Lucas, J.

1979-01-01

277

Innovative nuclear thermal propulsion technology evaluation - Results of the NASA/DOE task team study  

NASA Technical Reports Server (NTRS)

In response to findings from two NASA/DOE nuclear propulsion workshops, six task teams were created to continue evaluation of various propulsion concepts, from which evolved an innovative concepts subpanel to evaluate thermal propulsion concepts which did not utilize solid fuel. This subpanel endeavored to evaluate each concept on a level technology basis, and to identify critical issues, technologies, and early proof-of-concept experiments. Results of the concept studies including the liquid core fission, the gas core fission, the fission foil reactors, explosively driven systems, fusion, and antimatter are presented.

Howe, Steven D.; Borowski, Stanley; Motloch, Chet; Helms, Ira; Diaz, Nils; Anghaie, Samim; Latham, Thomas

1991-01-01

278

Aerial visible-thermal infrared hyperspectral feature extraction technology and its application to object identification  

NASA Astrophysics Data System (ADS)

Based on aerial visible-thermal infrared hyperspectral imaging system (CASI/SASI/TASI) data, field spectrometer data and multi-source geological information, this paper utilizes the hyperspectral data processing and feature extraction technology to identify uranium mineralization factors, the spectral features of typical tetravalent, hexavalent uranium minerals and mineralization factors are established, and hyperspectral logging technology for drill cores and trench also are developed, the relationships between radioactive intensity and spectral characteristics are built. Above methods have been applied to characterize uranium mineralization setting of granite-type and sandstone-type uranium deposits in south and northwest China, the successful outcomes of uranium prospecting have been achieved.

Jie-lin, Zhang; Jun-hu, Wang; Mi, Zhou; Yan-ju, Huang; Ding, Wu

2014-03-01

279

Active infrared thermal imaging technology to detect the corrosion defects in aircraft cargo door  

NASA Astrophysics Data System (ADS)

Aircraft fuselage material corrosion problems have been major aviation security issues, which hinder the development of aviation industry. How can we use non-destructive testing methods to detect the internal corrosion defects from the outside of the fuselage, to find the hidden safety problems in advance and update the defective equipment and materials, has great significance for the prevention of accidents. Nowadays, the active infrared thermal imaging technology as a new nondestructive technology has been gradually used on a wide variety of materials, such as composite, metal and so on. This article makes use of this technology on an aircraft cargo door specimen to detect the corrosion defects. Firstly, use High-energy flash pulse to excite the specimen, and use the thermal image processing software to splice the thermal images, so the thermal images of the overall specimen can be showed. Then, heat the defects by ultrasonic excitation, this will cause vibration and friction or thermoelastic effects in the places of defects, so the ultrasonic energy will dissipate into heat and manifested in the uneven temperature of surface. An Infrared camera to capture the changes of temperature of material surface, send data to the computer and records the thermal information of the defects. Finally, extracting data and drawing infrared radiation-time curve of some selected points of interest to analyze the signal changes in heat of defects further more. The results of the experiments show that both of the two ways of heat excitation show a clear position and shape of defects, and the ultrasonic method has more obvious effect of excitation to the defects, and a higher signal to noise ratio than the flash pulse excitation, but flash pulse method do not contact the specimen in the process of excitation, and shows the location and shape of defects in the overall of the specimen has its advantages.

Chen, Dapeng; Zhang, Cunlin; Zeng, Zhi; Xing, Chunfei; Li, Yanhong

2009-11-01

280

Thermal comfort in the humid tropics: Field experiments in air conditioned and naturally ventilated buildings in Singapore  

NASA Astrophysics Data System (ADS)

Thermal comfort field experiments were conducted in Singapore in both naturally ventilated highrise residential buildings and air conditioned office buildings. Each of the 818 questionnaire responses was made simultaneously with a detailed set of indoor climatic measurements, and estimates of clothing insulation and metabolic rate. Results for the air conditioned sample indicated that office buildings were overcooled, causing up to one-third of their occupants to experience cool thermal comfort sensations. These observations in air conditioned buildings were broadly consistent with the ISO, ASHRAE and Singapore indoor climatic standards. Indoor climates of the naturally ventilated apartments during the day and early evening were on average three degrees warmer than the ISO comfort standard prescriptions, but caused much less thermal discomfort than expected. Discrepancies between thermal comfort responses in apartment blocks and office buildings are discussed in terms of contemporary perceptual theory.

de Dear, R. J.; Leow, K. G.; Foo, S. C.

1991-12-01

281

Effects of Thermal and Cryogenic Conditionings on Flexural Behavior of Thermally Shocked Cu-Al2O3 Micro and NanoComposites  

NASA Astrophysics Data System (ADS)

This investigation has used flexural test to explore the effects of thermal treatments, i.e., high-temperature and cryogenic environments on the mechanical property of Al2O3 particulate-reinforced Cu metal matrix micro and nanocomposites in ex-situ and in-situ conditions. Cu-5 vol. pct Al2O3 micro (10 ?m)- and nanocomposites (<50 nm) fabricated by powder metallurgy route were subjected to up-thermal shock cycle [193 K to 353 K (-80 °C to 80 °C)] and down-thermal shock cycle [353 K to 193 K (from 80 °C to -80 °C)] for different time periods followed by 3-point bend test. One batch of specimens (micro and nanocomposites) was conditioned at 353 K and 193 K (80 °C and -80 °C) separately followed by 3-point flexural test. High-temperature flexural test was performed at 373 K and 523 K (80 °C and 250 °C) on the micro and nanocomposites. All the fractured samples obtained after various thermal treatments were studied under scanning electron microscope (SEM). The development of thermal stresses quite often results in concentration of residual stresses at the particle/matrix interface eventually weakening it. Enhancement of flexural strength was recorded for down- as well as for up-thermal shock in microcomposites. The high-temperature flexural strengths of micro and nanocomposites are lower than those at ambient temperature. The amelioration and declination in mechanical properties as a consequence of thermal shock, thermal conditioning, and high-temperature flexural testing have been discussed in the light of fractography.

Dash, Khushbu; Panda, Sujata; Ray, Bankim Chandra

2013-10-01

282

Building Thermal Envelope Systems and Materials (BTESM) and research utilization/technology transfer  

SciTech Connect

The Monthly Report of the Building Thermal Envelope Systems and Materials (BTESM) Programs is a monthly update of both in-house ORNL projects and subcontract activities in the research areas of building materials, wall systems, foundations, roofs, building diagnostics, and research utilization and technology transfer. Presentations are not stand-alone paragraphs every month. Their principal values are the short-time lapse between accomplishment and reporting and their evolution over a period of several months..

Burn, G. (comp.)

1990-07-01

283

Building Thermal Envelope Systems and Materials (BTESM) and research utilization\\/technology transfer  

Microsoft Academic Search

The Monthly Report of the Building Thermal Envelope Systems and Materials (BTESM) Programs is a monthly update of both in-house ORNL projects and subcontract activities in the research areas of building materials, wall systems, foundations, roofs, building diagnostics, and research utilization and technology transfer. Presentations are not stand-alone paragraphs every month. Their principal values are the short-time lapse between accomplishment

Burn

1990-01-01

284

Solvated Electron Technology{sup TM}. Non-Thermal Alternative to Waste Incineration  

Microsoft Academic Search

Solvated Electron Technology (SET{sup TM}) is a patented non-thermal alternative to incineration for treating Toxic Substances Control Act (TSCA) and other mixed waste by destroying organic hazardous components. SET{sup TM} is a treatment process that destroys the hazardous components in mixed waste by chemical reduction. The residual material meets land disposal restriction (LDR) and TSCA requirements for disposal. In application,

W. L. Foutz; J. E. Rogers; J. D. Mather

2008-01-01

285

Integration of screen-printing and rapid thermal processing technologies for silicon solar cell fabrication  

Microsoft Academic Search

For the first time, the potentially cost-effective technologies of rapid thermal processing (RTP) and screen-printing (SP) have been combined into a single process sequence to achieve solar cell efficiencies as high as 14.7% on 0.2 ?-cm FZ and 14.8% on 3 ?-cm Cz silicon. These results were achieved without application of a nonhomogeneous (selective) emitter, texturing, or oxide passivation. By

P. Doshi; J. Mejia; K. Tate; A. Rohatgi

1996-01-01

286

Thermal conditions during juvenile development affect adult dispersal in a spider  

PubMed Central

Understanding the causes and consequences of dispersal is a prerequisite for the effective management of natural populations. Rather than treating dispersal as a fixed trait, it should be considered a plastic process that responds to both genetic and environmental conditions. Here, we consider how the ambient temperature experienced by juvenile Erigone atra, a spider inhabiting crop habitat, influences adult dispersal. This species exhibits 2 distinct forms of dispersal, ballooning (long distance) and rappelling (short distance). Using a half-sib design we raised individuals under 4 different temperature regimes and quantified the spiders' propensity to balloon and to rappel. Additionally, as an indicator of investment in settlement, we determined the size of the webs build by the spiders following dispersal. The optimal temperature regimes for reproduction and overall dispersal investment were 20 °C and 25 °C. Propensity to perform short-distance movements was lowest at 15 °C, whereas for long-distance dispersal it was lowest at 30 °C. Plasticity in dispersal was in the direction predicted on the basis of the risks associated with seasonal changes in habitat availability; long-distance ballooning occurred more frequently under cooler, spring-like conditions and short-distance rappelling under warmer, summer-like conditions. Based on these findings, we conclude that thermal conditions during development provide juvenile spiders with information about the environmental conditions they are likely to encounter as adults and that this information influences the spider's dispersal strategy. Climate change may result in suboptimal adult dispersal behavior, with potentially deleterious population level consequences. PMID:18974219

Bonte, Dries; Travis, Justin M. J.; De Clercq, Nele; Zwertvaegher, Ingrid; Lens, Luc

2008-01-01

287

Thermal Energy for Lunar In Situ Resource Utilization: Technical Challenges and Technology Opportunities  

NASA Technical Reports Server (NTRS)

Oxygen production from lunar raw materials is critical for sustaining a manned lunar base but is very power intensive. Solar concentrators are a well-developed technology for harnessing the Sun s energy to heat regolith to high temperatures (over 1375 K). The high temperature and potential material incompatibilities present numerous technical challenges. This study compares and contrasts different solar concentrator designs that have been developed, such as Cassegrains, offset parabolas, compound parabolic concentrators, and secondary concentrators. Differences between concentrators made from lenses and mirrors, and between rigid and flexible concentrators are also discussed. Possible substrate elements for a rigid mirror concentrator are selected and then compared, using the following (target) criteria: (low) coefficient of thermal expansion, (high) modulus of elasticity, and (low) density. Several potential lunar locations for solar concentrators are compared; environmental and processing-related challenges related to dust and optical surfaces are addressed. This brief technology survey examines various sources of thermal energy that can be utilized for materials processing on the lunar surface. These include heat from nuclear or electric sources and solar concentrators. Options for collecting and transporting thermal energy to processing reactors for each source are examined. Overall system requirements for each thermal source are compared and system limitations, such as maximum achievable temperature are discussed.

Gordon, Pierce E. C.; Colozza, Anthony J.; Hepp, Aloysius F.; Heller, Richard S.; Gustafson, Robert; Stern, Ted; Nakamura, Takashi

2011-01-01

288

Optimization of the thermal conditions for processing hatchery waste eggs as meal for feed.  

PubMed

The purpose of this study was to optimize the thermal conditions for processing hatchery waste eggs (HWE) into rich feedstuff with lower electricity consumption by using response surface methodology. In the study, the effects of processing temperature and time on HWE meal (HWEM) quality and production were evaluated. As the results indicate, optimization was obtained when the processing lasted for 23 h at the fixed temperature of 65°C, resulting in higher protein digestibility in vitro (89.6%) and DM (88.5%) content of HWEM with lower electricity consumption (82.4 kWh/60 kg of HWE). No significant differences existed between the quality values predicted by mathematical formulae and those obtained through practical analyses in DM (87 vs. 88.5%), CP (39.2 vs. 38.3%), protein digestibility in vitro (90.7 vs. 89.6%), and electricity consumed (80.8 vs. 82.4 kWh/60 kg of HWE). Furthermore, the product derived from the optimized processing conditions had better biosecurity; Salmonella spp. were not found and Escherichia coli levels were substantially reduced (from 10(7) to 10(4) cfu/g). In summary, HWEM of superior quality can be produced when the processing conditions optimized in the current research are utilized. PMID:21489958

Chiu, W Z; Wei, H W

2011-05-01

289

INCREASING HEAVY OIL RESERVES IN THE WILMINGTON OIL FIELD THROUGH ADVANCED RESERVOIR CHARACTERIZATION AND THERMAL PRODUCTION TECHNOLOGIES  

Microsoft Academic Search

The objective of this project is to increase the recoverable heavy oil reserves within sections of the Wilmington Oil Field, near Long Beach, California, through the testing and application of advanced reservoir characterization and thermal production technologies. The hope is that successful application of these technologies will result in their implementation throughout the Wilmington Field and, through technology transfer, will

2001-01-01

290

Simulation of the ocean's spectral radiant thermal source and boundary conditions  

NASA Astrophysics Data System (ADS)

This article considers the analysis of radiant heat transfer for semitransparent natural and polluted seawaters and its physical interpretations. Technogenic or natural pollutions are considered as ensembles of selective scattering, absorbing and emitting particles with complex refractive indices in difference spectral ranges of external radiation. Simulation of spectral radiant thermal sources within short wavelength of solar penetrating radiation for upper oceanic depth was carried out for deep seawater on regions from ˜ 300 to ˜ 600 nm and for subsurface layers (not more ˜ 1 m) - on one ˜ 600 - 1200 nm. Model boundary conditions on exposed oceanic surface are defined by (1) emittance of atmosphere and seawater within long wavelength radiation ˜ 9000 nm, (2) convection, and (3) thermal losses due to evaporation. Spatial and temporal variability of inherent optical properties, temperature distributions of the upper overheated layer of seawater, the appearance of a subsurface temperature maximum and a cool surface skin layer in response to penetrating solar radiation are explained first of all by the effects of volumetric scattering (absorption) and surface cooling of polluted seawater. The suggested analysis can become an important and useful subject of research for oceanographers and climatologists.

Merzlikin, Vladimir; Krass, Maxim; Cheranev, Svyatoslav; Aloric, Aleksandra

2013-05-01

291

[Optimizing remediation conditions of non-thermal plasma for DDTs heavily contaminated soil].  

PubMed

A series of experiments were carried out in a non-thermal reactor to remove DDTs in heavily contaminated soil by dielectric barrier discharge (DBD). The study aims to investigate the effects of soil properties (including soil particle size and soil water content) and equipment working parameters (e. g. the plasma power, the processing time and discharge atmosphere) on the removal of DDTs from soil. The results showed that DDTs in soil were significantly degraded by the non-thermal plasma produced by dielectric barrier discharge. Removal rate of DDTs increased with increasing processing time. The removal efficiency of DDTs ranged from 95.3% to 99.9% in 20 minutes. The optimum conditions were as follows: 1 kW of the plasma power, 20 minutes of processing time in air discharge atmosphere, 0-0.9 mm soil particle size and 4.5% -10.5% of soil moisture content. The results also showed that o,p'-DDE might be the intermediate dechlorination and dehydrogenation product of the o,p'-DDT after the oxidization. PMID:23487955

Chen, Hai-Hong; Luo, Yong-Ming; Teng, Ying; Liu, Wu-Xing; Pan, Cheng; Li, Zhen-Gao; Huang, Yu-Juan

2013-01-01

292

Influence of thermal environment on optimal working conditions of thermoelectric generators  

NASA Astrophysics Data System (ADS)

Optimization analysis of thermoelectric generators operation is of importance both for practical applications and theoretical considerations. Depending on the desired goal, two different strategies are possible to achieve high performance: through optimization one may seek either power output maximization or conversion efficiency maximization. Recent literature reveals the persistent flawed notion that these two optimal working conditions may be achieved simultaneously. In this article, we lift all source of confusion by correctly posing the problem and solving it. We assume and discuss two possibilities for the environment of the generator to govern its operation: constant incoming heat flux, and constant temperature difference between the heat reservoirs. We demonstrate that, while power and efficiency are maximized simultaneously if the first assumption is considered, this is not possible with the second assumption. This latter corresponds to the seminal analyses of Ioffe who put forth and stressed the importance of the thermoelectric figure of merit ZT. We also provide a simple procedure to determine the different optimal design parameters of a thermoelectric generator connected to heat reservoirs through thermal contacts with a finite and fixed thermal conductance.

Apertet, Y.; Ouerdane, H.; Goupil, C.; Lecoeur, Ph.

2014-10-01

293

Thermal conditions in a hot evaporating cathode in a stationary vacuum arc with diffuse cathode emission  

SciTech Connect

A study has been made of an arc on a thermally insulated metal cathode with indirect electron-beam heating. The cathode material (gadolinium) resembles ordinary refractory metals in having a small ratio of the evaporated-atom flux to the thermionic-emission electron one. At cathode temperatures T /SUB c/ greater than or equal to 1900/sup 0/K and saturation-vapor pressures greater than or equal to Pa, one gets stationary diffuse cathode emission with a mean current density of 10-100 A/cm/sup 2/. A method has been developed from measuring the heat flux Q*c, which is the difference between the flux from the plasma to the cathode and the flux transported from the cathode by electron emission. As the heating power and correspondingly T /SUB c/ increase, Q*c decreases, and there is a continuous transition from the self-heated condition with Q*c > O to the externally heated one Q*c < O. This Q*c(Tc) dependence provides for thermal stability of the diffuse cathode emission. In the first state, the ratio of the thermionic emission current to the arc current is about1, while in the second it is >1. To explain the cathode heating at maximal values Q*c > O by the ion flux from the plasma, it has to be assumed that there are highly charged ions with energies of about200 eV.

Paranin, S.N.; Polishchuk, V.P.; Shabashov, V.I.; Sychev, P.E.; Yartsev, I.M.

1986-11-01

294

On the effective thermal conductivity of wetted zeolite under the working conditions of an adsorption chiller  

Microsoft Academic Search

This paper presents a theoretical model for predicting the effective thermal conductivity of wetted zeolite. The model comprises the thermal conductivities of the zeolite crystal as well as of the adsorbed water. The temperature dependence of both thermal conductivities is considered. Moreover, the contribution to the effective thermal conductivity due to vapor conductance is also taken into account. The effective

B. Dawoud; M. Imroz Sohel; A. Freni; S. Vasta; G. Restuccia

2011-01-01

295

Numerical simulations of thermal convection in rotating spherical shells under laboratory conditions  

NASA Astrophysics Data System (ADS)

An exhaustive study, based on numerical three-dimensional simulations, of the Boussinesq thermal convection of a fluid confined in a rotating spherical shell is presented. A moderately low Prandtl number fluid (?=0.1) bounded by differentially-heated solid spherical shells is mainly considered. Asymptotic power laws for the mean physical properties of the flows are obtained in the limit of low Rossby number and compared with laboratory experiments and with previous numerical results computed by taking either stress-free boundary conditions or quasi-geostrophic restrictions, and with geodynamo models. Finally, using parameters as close as possible to those of the Earth's outer core, some estimations of the characteristic time and length scales of convection are given.

Garcia, Ferran; Sánchez, Juan; Net, Marta

2014-05-01

296

Mineralization behavior of fluorine in perfluorooctanesulfonate (PFOS) during thermal treatment of lime-conditioned sludge.  

PubMed

The fate and transport of the fluorine in perfluorooctanesulfonate (PFOS) during the thermal treatment of lime-conditioned sludge were observed using both qualitative and quantitative X-ray diffraction techniques. Two main fluorine mineralization mechanisms leading to the substantial formation of CaF2 and Ca5(PO4)3F phases were observed. They had a close relationship with the thermal treatment condition and the PFOS content of the sludge. At low temperatures (300-600 °C), CaF2 dominated in the product and increases in treatment time and temperature generally enhanced the fluorine transformation. However, at higher temperatures (700-900 °C), increases in treatment time and temperature had a negative effect on the overall efficiency of the fluorine crystallization. The results suggest that in the high temperature environment there were greater losses of gaseous products such as HF and SiF4 in the transformation of CaF2 to Ca5(PO4)3F, the hydrolysis of CaF2, and the reaction with SiO2. The quantitative analysis also showed that when treating sludge with low PFOS content at high temperatures, the formation of Ca5(PO4)3F may be the primary mechanism for the mineralization of the fluorine in PFOS. The overall results clearly indicate the variations in the fate and transport of fluorine in PFOS when the sludge is subject to different PFOS contents and treatment types, such as heat drying or incineration. PMID:23360134

Wang, Fei; Shih, Kaimin; Lu, Xingwen; Liu, Chengshuai

2013-03-19

297

Hydrodynamic behaviour of micro/nanoscale Poiseuille flow under thermal creep condition  

NASA Astrophysics Data System (ADS)

Current work investigates the effect of thermal creep on the behavior of rarefied gas flow through micro/nanochannels using the direct simulation Monte Carlo method. Thermal creep effects are studied on velocity profiles, streamwise velocity and pressure, and thermal mass flow rate. The strength of thermal creep is examined at different Knudsen number, channel pressure ratio, and bulk temperature. The thermal mass flow rate variation is investigated over a wide range of flow rarefaction from the slip to free molecular regime.

Akhlaghi, Hassan; Balaj, Mojtaba; Roohi, Ehsan

2013-08-01

298

Thermal energy recovery of air conditioning system––heat recovery system calculation and phase change materials development  

Microsoft Academic Search

Latent heat thermal energy storage systems can be used to recover the rejected heat from air conditioning systems, which can be used to generate low-temperature hot water. It decreases not only the consumption of primary energy for heating domestic hot water but also the calefaction to the surroundings due to the rejection of heat from air conditioning systems. A recovery

Zhaolin Gu; Hongjuan Liu; Yun Li

2004-01-01

299

The effects of stationary periods and external temperature and humidity on thermal stress conditions within sheep transport vehicles  

Microsoft Academic Search

AIM: To identify the contributions of stationary periods and external climatic environments to thermal stress conditions for sheep on livestock transport vehicles during journeys in summer.METHODS: Two livestock transport vehicles carrying sheep, operating under commercial conditions in New Zealand, were monitored during February and March 2002. Temperature and humidity were logged in five pens inside each vehicle, as well as

AD Fisher; M Stewart; DM Duganzich; J Tacon; LR Matthews

2005-01-01

300

Effect of fee-for-service air-conditioning management in balancing thermal comfort and energy usage.  

PubMed

Balancing thermal comfort with the requirement of energy conservation presents a challenge in hot and humid areas where air-conditioning (AC) is frequently used in cooling indoor air. A field survey was conducted in Taiwan to demonstrate the adaptive behaviors of occupants in relation to the use of fans and AC in a school building employing mixed-mode ventilation where AC use was managed under a fee-for-service mechanism. The patterns of using windows, fans, and AC as well as the perceptions of students toward the thermal environment were examined. The results of thermal perception evaluation in relation to the indoor thermal conditions were compared to the levels of thermal comfort predicted by the adaptive models described in the American Society of Heating, Refrigerating, and Air-Conditioning Engineers Standard 55 and EN 15251 and to that of a local model for evaluating thermal adaption in naturally ventilated buildings. A thermal comfort-driven adaptive behavior model was established to illustrate the probability of fans/AC use at specific temperature and compared to the temperature threshold approach to illustrate the potential energy saving the fee-for-service mechanism provided. The findings of this study may be applied as a reference for regulating the operation of AC in school buildings of subtropical regions. PMID:24510118

Chen, Chen-Peng; Hwang, Ruey-Lung; Shih, Wen-Mei

2014-11-01

301

A comparative analysis of human thermal conditions in outdoor urban spaces in the summer season in Singapore and Changsha, China.  

PubMed

This paper presents the comparative analysis between the findings from two field surveys of human thermal conditions in outdoor urban spaces during the summer season. The first survey was carried out from August 2010 to May 2011 in Singapore and the second survey was carried out from June 2010 to August 2010 in Changsha, China. The physiologically equivalent temperature (PET) was utilized as the thermal index to assess the thermal conditions. Differences were found between the two city respondents in terms of thermal sensation, humidity sensation, and wind speed sensation. No big difference was found between the two city respondents regarding the sun sensation. The two city respondents had similar neutral PET of 28.1 °C for Singapore and 27.9 °C for Changsha, respectively. However, Singapore respondents were more sensitive to PET change than Changsha respondents and the acceptable PET range for Changsha respondents was wider than that for Singapore respondents. Besides, the two city respondents had different thermal expectations with the preferred PET of 25.2 °C and 22.1 °C for Singapore and Changsha, respectively. The results also reveal that Changsha respondents were more tolerant than Singapore respondents under hot conditions. Finally, two regression models were proposed for Singapore and Changsha to predict the human thermal sensation in a given outdoor thermal environment. PMID:23250734

Yang, Wei; Wong, Nyuk Hien; Zhang, Guoqiang

2013-11-01

302

Effect of fee-for-service air-conditioning management in balancing thermal comfort and energy usage  

NASA Astrophysics Data System (ADS)

Balancing thermal comfort with the requirement of energy conservation presents a challenge in hot and humid areas where air-conditioning (AC) is frequently used in cooling indoor air. A field survey was conducted in Taiwan to demonstrate the adaptive behaviors of occupants in relation to the use of fans and AC in a school building employing mixed-mode ventilation where AC use was managed under a fee-for-service mechanism. The patterns of using windows, fans, and AC as well as the perceptions of students toward the thermal environment were examined. The results of thermal perception evaluation in relation to the indoor thermal conditions were compared to the levels of thermal comfort predicted by the adaptive models described in the American Society of Heating, Refrigerating, and Air-Conditioning Engineers Standard 55 and EN 15251 and to that of a local model for evaluating thermal adaption in naturally ventilated buildings. A thermal comfort-driven adaptive behavior model was established to illustrate the probability of fans/AC use at specific temperature and compared to the temperature threshold approach to illustrate the potential energy saving the fee-for-service mechanism provided. The findings of this study may be applied as a reference for regulating the operation of AC in school buildings of subtropical regions.

Chen, Chen-Peng; Hwang, Ruey-Lung; Shih, Wen-Mei

2014-02-01

303

Thermal-hydraulic instabilities in natural circulation flow loops under supercritical conditions  

NASA Astrophysics Data System (ADS)

In recent years, a growing interest has been generated in investigating the thermal hydraulics and flow stability phenomenon in supercritical natural circulation loops. These flow conditions are relevant to some of the innovative passive safety designs proposed for the Gen-IV Supercritical Water Reactor (SCWR) concepts. A computational model has been developed at UW Madison which provides a good basic simulation tool for the steady state and transient analysis of one dimensional natural circulation flow, and can be applied to conduct stability analysis. Several modifications and improvements were incorporated in an earlier numerical scheme before applying it to investigate the transient behavior of two experimental loops, namely, the supercritical water loop at UW-Madison and the supercritical carbon-dioxide (SCCO2) loop at Argonne National Laboratories. Although the model predicted development of instabilities for both SCW and SCCO2 loop which agrees with some previous work, the experiments conducted at SCCO2 loop exhibited stable behavior under similar conditions. To distinguish between numerical effects and physical processes, a linear stability approach has also been developed to investigate the stability characteristics associated with the natural circulation loop systems for various inlet conditions, input powers and geometries. The linear stability results for the SCW and SCCO2 loops exhibited differences with the corresponding transient simulations. This linear model also predicted the presence of instability in the SCCO 2 loop for certain high input powers contradictory to the experimental findings. Dimensionless parameters were proposed which would generalize the stability characteristics of the natural circulation flow loops under supercritical conditions.

Jain, Rachna

304

Mt. Washington Icing Sensors Project (MWISP) Tests Technologies for Remote Sensing of Icing Conditions  

NASA Technical Reports Server (NTRS)

The Mt. Washington Icing Sensors Project (MWISP) was an intensive multiagency field test of remote-sensing technologies and methods for in-flight icing detection. This field test was the first comprehensive examination of multiple remote-sensing technologies, and it included ground and airborne in situ measurements for comparison. The data gathered will allow the assessment of icing remote-sensing technologies leading toward the development of ground-based and airborne systems. These systems will provide flight crews with the information required for avoiding or exiting hazardous icing conditions.

Reehorst, Andrew L.

2000-01-01

305

Thermal power systems point-focusing distributed receiver technology project. Volume 1: Executive summary  

NASA Technical Reports Server (NTRS)

Thermal or electrical power from the sun's radiated energy through Point-Focusing Distributed Receiver Technology is the goal of this project. The energy thus produced must be technically, as well as economically, competitive with other energy sources. This project is to support the industrial development of the required technology to achieve the above stated goal. Solar energy is concentrated by either a reflecting surface or a lense to a receiver where it is transferred to a working liquid or gas. Receiver temperatures are in the 1000 - 2000 F range. Conceptual design studies are expected to identify power conversion units with a viable place in the solar energy future. Rankine and Brayton cycle engines are under investigation. This report details the Jet Propulsion Laboratory's accomplishments with point-focusing technology in Fy 1978.

Lucas, J.

1979-01-01

306

Fast access to the CMS detector condition data employing HTML5 technologies  

NASA Astrophysics Data System (ADS)

This paper focuses on using HTML version 5 (HTML5) for accessing condition data for the CMS experiment, evaluating the benefits and risks posed by the use of this technology. According to the authors of HTML5, this technology attempts to solve issues found in previous iterations of HTML and addresses the needs of web applications, an area previously not adequately covered by HTML. We demonstrate that employing HTML5 brings important benefits in terms of access performance to the CMS condition data. The combined use of web storage and web sockets allows increasing the performance and reducing the costs in term of computation power, memory usage and network bandwidth for client and server. Above all, the web workers allow creating different scripts that can be executed using multi-thread mode, exploiting multi-core microprocessors. Web workers have been employed in order to substantially decrease the web page rendering time to display the condition data stored in the CMS condition database.

Pierro, Giuseppe Antonio; Cavallari, Francesca; Di Guida, Salvatore; Innocente, Vincenzo

2011-12-01

307

Application and development of technologies for engine-condition-based maintenance of emergency diesel generators  

SciTech Connect

The emergency diesel generator (EDG) of a nuclear power plant has the role of supplying emergency electric power to protect the reactor core system in the event of the loss of offsite power supply. Therefore, EDGs should be subject to periodic surveillance testing to verify their ability to supply specified frequencies and voltages at design power levels within a limited time. To maintain optimal reliability of EDGs, condition monitoring/diagnosis technologies must be developed. Changing from periodic disassemble maintenance to condition-based maintenance (CBM) according to predictions of equipment condition is recommended. In this paper, the development of diagnosis technology for CBM and the application of a diesel engine condition-analysis system are described. (authors)

Choi, K. H.; Sang, G.; Choi, L. Y. S.; Lee, B. O. [Korea Hydro and Nuclear Power Company Central Research Institue, 70, 1312 -gil Yuseong-daero Yuseong-gu, Daejeon 305-343 (Korea, Republic of)

2012-07-01

308

Effects of thermal curing conditions on drug release from polyvinyl acetate-polyvinyl pyrrolidone matrices.  

PubMed

This study aimed to investigate the effects of dry and humid heat curing on the physical and drug release properties of polyvinyl acetate-polyvinyl pyrrolidone matrices. Both conditions resulted in increased tablet hardness; tablets stored under humid conditions showed high plasticity and deformed during hardness testing. Release from the matrices was dependent on the filler's type and level. Release profiles showed significant changes, as a result of exposure to thermal stress, none of the fillers used stabilized matrices against these changes. Density of neat polymeric compacts increased upon exposure to heat; the effect of humid heat was more evident than dry heat. Thermograms of samples cured under dry heat did not show changes, while those of samples stored under high humidity showed significant enlargement of the dehydration endotherm masking the glass transition of polyvinyl acetate. The change of the physical and release properties of matrices could be explained by the hygroscopic nature of polyvinyl pyrrolidone causing water uptake; absorbed water then acts as a plasticizer of polyvinyl acetate promoting plastic flow, deformation, and coalescence of particles, and altering the matrices internal structure. Results suggest that humid heat is more effective as a curing environment than dry heat for polyvinyl acetate-polyvinyl pyrrolidone matrices. PMID:20174981

Alkhatib, Hatim S; Hamed, Saja; Mohammad, Mohammad K; Bustanji, Yasser; Alkhalidi, Bashar; Aiedeh, Khaled M; Najjar, Samer

2010-03-01

309

Gypsum scale formation on a heated copper plate under natural convection conditions and produced water remediation technologies review  

E-print Network

Scaling or crystallization fouling of unwanted salts is one of the most challenging and expensive problems encountered in different applications such as heat exchangers and thermal water treatment technologies. Formation ...

Mirhi, Mohamad H. (Mohamad Hussein)

2013-01-01

310

Real-time determination of optimal indoor-air condition for thermal comfort, air quality and efficient energy usage  

Microsoft Academic Search

For building, “surroundings” that effect on indoor-air condition change with respect to the time. Without proper determination of the desired indoor-air condition to heating, ventilating and air-conditioning (HVAC) system, it may not be feasible to provide simultaneously occupants with thermal comfort and acceptable air quality with efficient energy consumption all the time. This paper presents an alternative methodology of real-time

S Atthajariyakul; T Leephakpreeda

2004-01-01

311

Multilayer SiC for thermal protection system of space vehicles: Manufacturing and testing under simulated re-entry conditions  

Microsoft Academic Search

Two types of laminated multilayer silicon carbide plates were processed by tape casting, de-binding and pressureless sintering. The specimens were subject to thermal re-entry testing under conditions as derived from the HERMES study: up to 100 combined thermal and air pressure cycles were performed. After the first cycle, all samples lost about 1.5% of their initial mass. This was caused

S. Biamino; V. Liedtke; C. Badini; G. Euchberger; I. Huertas Olivares; M. Pavese; P. Fino

2008-01-01

312

Assessment of thermal load on transported goats administered with ascorbic acid during the hot-dry conditions  

Microsoft Academic Search

The major factor in the induction of physiological stress during road transportation of livestock is the complex fluctuations\\u000a of the thermal transport microenvironment, encountered when animals are transported across different ecological zones. Recommended\\u000a guidelines on optimum “on-board” conditions in which goats should be transported are lacking, and there are no acceptable\\u000a ranges and limits for the thermal loads to which

N. S. Minka; J. O. Ayo

313

TECHNOLOGY DEMONSTRATION SUMMARY: THE AMERICAN COMBUSTION PYRETRON THERMAL DESTRUCTION SYSTEM AT THE U.S. EPA'S COMBUSTION FACILITY  

EPA Science Inventory

The American Combustion Pyretron Thermal Destruction System at the U.S. EPA's Combustion Research Facility. Under the auspices of the Superfund Innovative Technology Evaluation, or SITE, program, a critical assessment was made of the American Combustion Pyretron? oxygen enha...

314

Thermal modeling of nickel-hydrogen battery cells operating under transient orbital conditions  

NASA Technical Reports Server (NTRS)

An analytical study of the thermal operating characteristics of nickel-hydrogen battery cells is presented. Combined finite-element and finite-difference techniques are employed to arrive at a computationally efficient composite thermal model representing a series-cell arrangement operating in conjunction with a radiately coupled baseplate and coldplate thermal bus. An aggressive, low-mass design approach indicates that thermal considerations can and should direct the design of the thermal bus arrangement. Special consideration is given to the potential for mixed conductive and convective processes across the hydrogen gap. Results of a compressible flow model are presented and indicate the transfer process is suitably represented by molecular conduction. A high-fidelity thermal model of the cell stack (and related components) indicates the presence of axial and radial temperature gradients. A detailed model of the thermal bus reveals the thermal interaction of individual cells and is imperative for assessing the intercell temperature gradients.

Schrage, Dean S.

1991-01-01

315

Thermal modeling of nickel-hydrogen battery cells operating under transient orbital conditions  

NASA Astrophysics Data System (ADS)

An analytical study of the thermal operating characteristics of nickel-hydrogen battery cells is presented. Combined finite-element and finite-difference techniques are employed to arrive at a computationally efficient composite thermal model representing a series-cell arrangement operating in conjunction with a radiately coupled baseplate and coldplate thermal bus. An aggressive, low-mass design approach indicates that thermal considerations can and should direct the design of the thermal bus arrangement. Special consideration is given to the potential for mixed conductive and convective processes across the hydrogen gap. Results of a compressible flow model are presented and indicate the transfer process is suitably represented by molecular conduction. A high-fidelity thermal model of the cell stack (and related components) indicates the presence of axial and radial temperature gradients. A detailed model of the thermal bus reveals the thermal interaction of individual cells and is imperative for assessing the intercell temperature gradients.

Schrage, Dean S.

316

Mercury recovery from cold cathode fluorescent lamps using thermal desorption technology.  

PubMed

Cold cathode fluorescent lamps (CCFLs) are globally used components of high technology products. A large amount of mercury in waste CCFLs is being recovered by thermal desorption technology in Taiwan. However, the complexity of the samples affects the thermal desorption efficiency and increases costs. This study identifies the mercury release behaviour of amalgam, phosphor and mercury-containing components as well as waste CCFLs by bench scale thermal desorption test. The results show that the mercury was released from amalgam and mercury/fluorescent powder from a real treatment plant at temperatures between 550 degrees C to 850 degrees C, which is much higher than from cinnabar at 300 degrees C to 380 degrees C and that of pure mercury, high pressure mercury lamps, and fluorescent tubes containing mercury/fluorescent-powder at 50 degrees C to 250 degrees C. In addition, the experiment also showed the mercury release peak of the mercury/fluorescent powders from a real treatment plant occurs at much higher temperatures than that of commercial phosphor at 50 degrees C to 200 degrees C. Thus, complete separation of the cracked CCFLs is necessary to effectively recover phosphor and mercury at low financial and energy cost. PMID:19723829

Chang, T C; Chen, C M; Lee, Y F; You, S J

2010-05-01

317

Condition Assessment of Ferrous Water Transmission and Distribution Systems State of Technology Review Report  

EPA Science Inventory

This White Paper was developed to serve as the basis for discussion at a Technology Forum on Condition Assessment of Water Transmission and Distribution Systems that was held on September 9 and 10, 2008, at Edison, NJ. It was distributed to the Forum participants for review in a...

318

Japanese power electronics inverter technology and its impact on the American air conditioning industry  

Microsoft Academic Search

Since 1983, technological advances and market growth of inverter-driven variable-speed heat pumps in Japan have been dramatic. The high level of market penetration was promoted by a combination of political, economic, and trade policies in Japan. A unique environment was created in which the leading domestic industries, microprocessor manufacturing, compressors for air conditioning and refrigerators, and power electronic devices, were

Kenji Ushimaru

1990-01-01

319

EPA FIELD DEMONSTRATION OF INNOVATIVE CONDITION ASSESSMENT TECHNOLOGIES FOR WATER MAINS AT LOUISVILLE, KY  

EPA Science Inventory

This presentation will describe a series of field demonstrations of innovative leak detection/location and condition assessment technologies that was sponsored by the U.S. Environmental Protection Agency (EPA), conducted by EPA?s contractor (Battelle), and hosted by the Louisvil...

320

Field Demonstration of Innovative Condition Assessment Technologies for Water Mains: Leak Detection and Location  

EPA Science Inventory

Three leak detection/location technologies were demonstrated on a 76-year-old, 2,057-ft-long portion of a cement-lined, 24-in. cast iron water main in Louisville, KY. This activity was part of a series of field demonstrations of innovative leak detection/location and condition a...

321

EPA Field Demonstration of Innovative Condition Assessment Technologies for Water Mains at Louisville, KY - slides  

EPA Science Inventory

This presentation will describe a series of field demonstrations of innovative leak detection/location and condition assessment technologies that was sponsored by the U.S. Environmental Protection Agency (EPA), conducted by EPA?s contractor (Battelle), and hosted by the Louisvill...

322

On-site mercury-contaminated soils remediation by using thermal desorption technology  

Microsoft Academic Search

In this study, the thermal desorption process was used to treat a mercury-contaminated soils in Taipei. A series of bench or pilot plant experiments were also performed the optimized operation condition. The results showed that the concentrations of residual mercury in all treated soils were below 2mg\\/kg, some even lower than 0.05mg\\/kg. The supernatant and exhaust gas stream of the

T. C. Chang; J. H. Yen

2006-01-01

323

A nonmolecular derivation of Maxwell's thermal-creep boundary condition in gases and liquids via application of the LeChatelier-Braun principle to Maxwell's thermal stress  

NASA Astrophysics Data System (ADS)

According to the LeChatelier-Braun principle, when a closed quiescent system initially in an equilibrium or unstressed steady state is subjected to an externally imposed "stress" it responds in a manner tending to alleviate that stress. Use of this entropically based qualitative rule, in combination with the notion of Maxwell thermal stresses existing in nonisothermal gases and liquids, enables one to (i) derive Maxwell's thermal-creep boundary condition prevailing at the boundary between a solid and a fluid (either gas or liquid) and (ii) rationalize the phenomenon of thermophoresis in liquids, for which, in contrast with the case of gases, an elementary explanation is currently lacking. These two objectives are achieved by quantitatively interpreting the heretofore qualitative LeChatelier-Braun notion of stress in the present context as being the fluid's stress tensor, the latter including Maxwell's thermal stress. In effect, thermophoretic particle motion is interpreted as the manifestation of the fluid's attempt to expel the particle from its interior so as to alleviate the thermal stress that would otherwise ensue were the particle to remain at rest (thus obeying the traditional no slip rather than thermal-creep boundary condition) following its introduction into the previously stress-free quiescent fluid. With Kn the Knudsen number in the case of rarefied gases, Maxwell's thermal stress constitutes a noncontinuum phenomenon of O(Kn2), whereas his thermal-creep phenomenon constitutes a continuum phenomenon of O(Kn). That these two phenomena can, nevertheless, be proved to be synonymous (in the sense, so to speak, of being two sides of the same coin), as is done in the present paper, supports the "ghost effect" findings of Sone [Y. Sone, "Flows induced by temperature fields in a rarefied gas and their ghost effect on the behavior of a gas in the continuum limit," Annu. Rev. Fluid Mech 32, 779 (2000)], which, philosophically, imply the artificiality of the distinction currently existing between continuum- and noncontinuum-level phenomena.

Brenner, Howard

2009-05-01

324

Carbon-rich Giant Planets: Atmospheric Chemistry, Thermal Inversions, Spectra, and Formation Conditions  

NASA Astrophysics Data System (ADS)

The recent inference of a carbon-rich atmosphere, with C/O >= 1, in the hot Jupiter WASP-12b motivates the exotic new class of carbon-rich planets (CRPs). We report a detailed study of the atmospheric chemistry and spectroscopic signatures of carbon-rich giant (CRG) planets, the possibility of thermal inversions in their atmospheres, the compositions of icy planetesimals required for their formation via core accretion, and the apportionment of ices, rock, and volatiles in their envelopes. Our results show that CRG atmospheres probe a unique region in composition space, especially at high temperature (T). For atmospheres with C/O >= 1, and T >~ 1400 K in the observable atmosphere, most of the oxygen is bound up in CO, while H2O is depleted and CH4 is enhanced by up to two or three orders of magnitude each, compared to equilibrium compositions with solar abundances (C/O = 0.54). These differences in the spectroscopically dominant species for the different C/O ratios cause equally distinct observable signatures in the spectra. As such, highly irradiated transiting giant exoplanets form ideal candidates to estimate atmospheric C/O ratios and to search for CRPs. We also find that the C/O ratio strongly affects the abundances of TiO and VO, which have been suggested to cause thermal inversions in highly irradiated hot Jupiter atmospheres. A C/O = 1 yields TiO and VO abundances of ~100 times lower than those obtained with equilibrium chemistry assuming solar abundances, at P ~ 1 bar. Such a depletion is adequate to rule out thermal inversions due to TiO/VO even in the most highly irradiated hot Jupiters, such as WASP-12b. We estimate the compositions of the protoplanetary disk, the planetesimals, and the envelope of WASP-12b, and the mass of ices dissolved in the envelope, based on the observed atmospheric abundances. Adopting stellar abundances (C/O = 0.44) for the primordial disk composition and low-temperature formation conditions (T <~ 30 K) for WASP-12b lead to a C/O ratio of 0.27 in accreted planetesimals, and, consequently, in the planet's envelope. In contrast, a C/O ratio of 1 in the envelope of WASP-12b requires a substantial depletion of oxygen in the disk, i.e., by a factor of ~0.41 for the same formation conditions. This scenario also satisfies the constraints on the C/H and O/H ratios reported for WASP-12b. If, alternatively, hotter conditions prevailed in a stellar composition disk such that only H2O is condensed, the remaining gas can potentially have a C/O ~ 1. However, a high C/O in WASP-12b caused predominantly by gas accretion would preclude superstellar C/H ratios which also fit the data.

Madhusudhan, Nikku; Mousis, Olivier; Johnson, Torrence V.; Lunine, Jonathan I.

2011-12-01

325

CARBON-RICH GIANT PLANETS: ATMOSPHERIC CHEMISTRY, THERMAL INVERSIONS, SPECTRA, AND FORMATION CONDITIONS  

SciTech Connect

The recent inference of a carbon-rich atmosphere, with C/O {>=} 1, in the hot Jupiter WASP-12b motivates the exotic new class of carbon-rich planets (CRPs). We report a detailed study of the atmospheric chemistry and spectroscopic signatures of carbon-rich giant (CRG) planets, the possibility of thermal inversions in their atmospheres, the compositions of icy planetesimals required for their formation via core accretion, and the apportionment of ices, rock, and volatiles in their envelopes. Our results show that CRG atmospheres probe a unique region in composition space, especially at high temperature (T). For atmospheres with C/O {>=} 1, and T {approx}> 1400 K in the observable atmosphere, most of the oxygen is bound up in CO, while H{sub 2}O is depleted and CH{sub 4} is enhanced by up to two or three orders of magnitude each, compared to equilibrium compositions with solar abundances (C/O = 0.54). These differences in the spectroscopically dominant species for the different C/O ratios cause equally distinct observable signatures in the spectra. As such, highly irradiated transiting giant exoplanets form ideal candidates to estimate atmospheric C/O ratios and to search for CRPs. We also find that the C/O ratio strongly affects the abundances of TiO and VO, which have been suggested to cause thermal inversions in highly irradiated hot Jupiter atmospheres. A C/O = 1 yields TiO and VO abundances of {approx}100 times lower than those obtained with equilibrium chemistry assuming solar abundances, at P {approx} 1 bar. Such a depletion is adequate to rule out thermal inversions due to TiO/VO even in the most highly irradiated hot Jupiters, such as WASP-12b. We estimate the compositions of the protoplanetary disk, the planetesimals, and the envelope of WASP-12b, and the mass of ices dissolved in the envelope, based on the observed atmospheric abundances. Adopting stellar abundances (C/O = 0.44) for the primordial disk composition and low-temperature formation conditions (T {approx}< 30 K) for WASP-12b lead to a C/O ratio of 0.27 in accreted planetesimals, and, consequently, in the planet's envelope. In contrast, a C/O ratio of 1 in the envelope of WASP-12b requires a substantial depletion of oxygen in the disk, i.e., by a factor of {approx}0.41 for the same formation conditions. This scenario also satisfies the constraints on the C/H and O/H ratios reported for WASP-12b. If, alternatively, hotter conditions prevailed in a stellar composition disk such that only H{sub 2}O is condensed, the remaining gas can potentially have a C/O {approx} 1. However, a high C/O in WASP-12b caused predominantly by gas accretion would preclude superstellar C/H ratios which also fit the data.

Madhusudhan, Nikku [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Mousis, Olivier [Institut UTINAM, CNRS-UMR 6213, Observatoire de Besancon, BP 1615, F-25010 Besancon Cedex (France); Johnson, Torrence V. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Lunine, Jonathan I., E-mail: nmadhu@astro.princeton.edu [Department of Astronomy, Cornell University, Ithaca, NY 14853 (United States)

2011-12-20

326

Experimental investigation on the photovoltaic-thermal solar heat pump air-conditioning system on water-heating mode  

SciTech Connect

An experimental study on operation performance of photovoltaic-thermal solar heat pump air-conditioning system was conducted in this paper. The experimental system of photovoltaic-thermal solar heat pump air-conditioning system was set up. The performance parameters such as the evaporation pressure, the condensation pressure and the coefficient of performance (COP) of heat pump air-conditioning system, the water temperature and receiving heat capacity in water heater, the photovoltaic (PV) module temperature and the photovoltaic efficiency were investigated. The experimental results show that the mean photovoltaic efficiency of photovoltaic-thermal (PV/T) solar heat pump air-conditioning system reaches 10.4%, and can improve 23.8% in comparison with that of the conventional photovoltaic module, the mean COP of heat pump air-conditioning system may attain 2.88 and the water temperature in water heater can increase to 42 C. These results indicate that the photovoltaic-thermal solar heat pump air-conditioning system has better performances and can stably work. (author)

Fang, Guiyin; Hu, Hainan; Liu, Xu [Department of Physics, Nanjing University, Nanjing 210093 (China)

2010-09-15

327

Investigation on the asymmetry of thermal condition and grain defect formation in the customary directional solidification process  

NASA Astrophysics Data System (ADS)

In the present study, the non-uniformity of the thermal condition and the corresponding grain defect formation in the customary Bridgman process were investigated. The casting clusters in radial alignment were directionally solidified in a Bridgman furnace. It was found that in the casting cluster, the shadow side facing the central rod was ineffectively heated in the hot zone and ineffectively cooled in the cooling zone during withdrawal, compared with the heater side facing the furnace heater. The metallographic examination of the simplified turbine blades exhibited that the platforms on the shadow side are very prone to stray grain formation, while the heater side reveals a markedly lower tendency for that. The asymmetric thermal condition causes the asymmetrical formation of these grain defects. This non-uniformity of the thermal condition should be minimized as far as possible, in order to effectively optimize the quality of the SC superalloy components.

Ma, D.; Wu, Q.; Hollad, S.; Bührig-Polaczek, A.

2012-01-01

328

Multi-Evaporator Miniature Loop Heat Pipe for Small Spacecraft Thermal Control. Part 1; New Technologies and Validation Approach  

NASA Technical Reports Server (NTRS)

Under NASA s New Millennium Program Space Technology 8 (ST 8) Project, four experiments Thermal Loop, Dependable Microprocessor, SAILMAST, and UltraFlex - were conducted to advance the maturity of individual technologies from proof of concept to prototype demonstration in a relevant environment , i.e. from a technology readiness level (TRL) of 3 to a level of 6. This paper presents the new technologies and validation approach of the Thermal Loop experiment. The Thermal Loop is an advanced thermal control system consisting of a miniature loop heat pipe (MLHP) with multiple evaporators and multiple condensers designed for future small system applications requiring low mass, low power, and compactness. The MLHP retains all features of state-of-the-art loop heat pipes (LHPs) and offers additional advantages to enhance the functionality, performance, versatility, and reliability of the system. Details of the thermal loop concept, technical advances, benefits, objectives, level 1 requirements, and performance characteristics are described. Also included in the paper are descriptions of the test articles and mathematical modeling used for the technology validation. An MLHP breadboard was built and tested in the laboratory and thermal vacuum environments for TRL 4 and TRL 5 validations, and an MLHP proto-flight unit was built and tested in a thermal vacuum chamber for the TRL 6 validation. In addition, an analytical model was developed to simulate the steady state and transient behaviors of the MLHP during various validation tests. Capabilities and limitations of the analytical model are also addressed.

Ku, Jentung; Ottenstein, Laura; Douglas, Donya; Hoang, Triem

2010-01-01

329

Latitudinal Discontinuity in Thermal Conditions along the Nearshore of Central-Northern Chile.  

PubMed

Over the past decade, evidence of abrupt latitudinal changes in the dynamics, structure and genetic variability of intertidal and subtidal benthic communities along central-northern Chile has been found consistently at 30-32°S. Changes in the advective and thermal environment in nearshore waters have been inferred from ecological patterns, since analyses of in situ physical data have thus far been missing. Here we analyze a unique set of shoreline temperature data, gathered over 4-10 years at 15 sites between 28-35°S, and combine it with satellite-derived winds and sea surface temperatures to investigate the latitudinal transition in nearshore oceanographic conditions suggested by recent ecological studies. Our results show a marked transition in thermal conditions at 30-31°S, superimposed on a broad latitudinal trend, and small-scale structures associated with cape-and-bay topography. The seasonal cycle dominated temperature variability throughout the region, but its relative importance decreased abruptly south of 30-31°S, as variability at synoptic and intra-seasonal scales became more important. The response of shoreline temperatures to meridional wind stress also changed abruptly at the transition, leading to a sharp drop in the occurrence of low-temperature waters at northern sites, and a concurrent decrease in corticated algal biomass. Together, these results suggest a limitation of nitrate availability in nearshore waters north of the transition. The localized alongshore change results from the interaction of latitudinal trends (e.g., wind stress, surface warming, inertial period) with a major headland-bay system (Punta Lengua de Vaca at 30.25°S), which juxtaposes a southern stretch of coast characterized by upwelling with a northern stretch of coast characterized by warm surface waters and stratification. This transition likely generates a number of latitude-dependent controls on ecological processes in the nearshore that can explain species-specific effects, and add strength to the suggestion of an oceanography-driven, major spatial transition in coastal communities at 30-31°S. PMID:25334020

Tapia, Fabian J; Largier, John L; Castillo, Manuel; Wieters, Evie A; Navarrete, Sergio A

2014-01-01

330

Latitudinal Discontinuity in Thermal Conditions along the Nearshore of Central-Northern Chile  

PubMed Central

Over the past decade, evidence of abrupt latitudinal changes in the dynamics, structure and genetic variability of intertidal and subtidal benthic communities along central-northern Chile has been found consistently at 30–32°S. Changes in the advective and thermal environment in nearshore waters have been inferred from ecological patterns, since analyses of in situ physical data have thus far been missing. Here we analyze a unique set of shoreline temperature data, gathered over 4–10 years at 15 sites between 28–35°S, and combine it with satellite-derived winds and sea surface temperatures to investigate the latitudinal transition in nearshore oceanographic conditions suggested by recent ecological studies. Our results show a marked transition in thermal conditions at 30–31°S, superimposed on a broad latitudinal trend, and small-scale structures associated with cape-and-bay topography. The seasonal cycle dominated temperature variability throughout the region, but its relative importance decreased abruptly south of 30–31°S, as variability at synoptic and intra-seasonal scales became more important. The response of shoreline temperatures to meridional wind stress also changed abruptly at the transition, leading to a sharp drop in the occurrence of low-temperature waters at northern sites, and a concurrent decrease in corticated algal biomass. Together, these results suggest a limitation of nitrate availability in nearshore waters north of the transition. The localized alongshore change results from the interaction of latitudinal trends (e.g., wind stress, surface warming, inertial period) with a major headland-bay system (Punta Lengua de Vaca at 30.25°S), which juxtaposes a southern stretch of coast characterized by upwelling with a northern stretch of coast characterized by warm surface waters and stratification. This transition likely generates a number of latitude-dependent controls on ecological processes in the nearshore that can explain species-specific effects, and add strength to the suggestion of an oceanography-driven, major spatial transition in coastal communities at 30–31°S. PMID:25334020

Tapia, Fabian J.; Largier, John L.; Castillo, Manuel; Wieters, Evie A.; Navarrete, Sergio A.

2014-01-01

331

Design of the Thermal Control System for the Space Technology 5 Microsatellite  

NASA Technical Reports Server (NTRS)

The New Millennium Program's (NMP) Space Technology 5 (ST-5) Project, currently in Phase B of the design process, is slated to launch three 20-kg class spin stabilized microsatellites in late 2003. The proposed orbit is highly elliptical and could result in an earth shadow eclipse of almost 2 hours. Although ST-5's maximum eclipse is only 2 hours, future missions could involve eclipses as long as 8 hours. As spacecraft size, mass, and available resources decrease and eclipse duration increases, thermal engineers will be challenged to design simple but robust thermal control systems that meet temperature requirements for all phases of the mission. This paper presents the results of a study of three design concepts and preliminary analysis of the design selected for ST-5.

Douglas, Donya; Michalek, Ted; Swanson, Ted; Brodeur, Stephen (Technical Monitor)

2001-01-01

332

Condition Monitoring and Fault Diagnosis of Wet-Shift Clutch Transmission Based on Multi-technology  

NASA Astrophysics Data System (ADS)

Based on the construction feature and operating principle of the wet-shift clutch transmission, the condition monitoring and fault diagnosis for the transmission of the tracklayer with wet-shift clutch were implemented with using the oil analysis technology, function parameter test method and vibration analysis technology. The new fault diagnosis methods were proposed, which are to build the gray modeling with the oil analysis data, and to test the function parameter of the clutch press, the rotate speed of each gear, the oil press of the steer system and lubrication system and the hydraulic torque converter. It's validated that the representative function signals were chosen to execute the condition monitoring analysis, when the fault symptoms were found, and the oil analysis data were used to apply the gray modeling to forecast the fault occurs time can satisfy the demand of the condition monitoring and fault diagnosis for the transmission regular work.

Chen, Man; Wang, Liyong; Ma, Biao

333

Improving heat pumps and air conditioning  

Microsoft Academic Search

This article reports that the search for technological advances is focusing on refrigerant replacements, mobile air conditioning and vapor compression technologies, and absorption and geothermal heat pumps. Heat pumps are devices that use an energy input to take thermal energy from a low-temperature thermal source (such as air, water, or the ground) and move it to a thermal sink that

K. D. Braven; S. Penoncello; K. Herold; Viung Mei; D. ONeal

1993-01-01

334

Scar prevention by laser-assisted scar healing (LASH) using thermal post-conditioning  

NASA Astrophysics Data System (ADS)

An 810-nm diode laser system was developed to accelerate and improve the healing process in surgical scars. Using thermal post-conditioning, the laser system provides a localised moderate heating whose maximum temperature is controlled to prevent tissue damage and stimulate the heat shock proteins (HSP) synthesis. The 810-nm wavelength allows a deep penetration of the light into the dermis, without damaging the epidermis. The time along which surgical incision is treated (continuous wave) must therefore be selected carefully with respect to the temperature precision achieved within the heated volume. A top-hat profile is preferred to a Gaussian profile in order to ensure the skin surface temperature is homogenised, as is the temperature of the heated volume. The spot shape will depend on the medical indication. The treatment should be made safe and controlled by means of a safety strip containing an RFID chip which will transmit the various operating settings to the laser device. A clinical trial aims at evaluating the 810 nm-diode laser in surgical incisions, with only one laser treatment immediately after skin closure, of patients with Fitzpatrick skin types I to IV. Surgical incisions were divided into two fields, with only portions randomly selected receiving laser treatment. At the final scar analysis (12 months) of the pilot study, the treated portion scored significantly better for both surgeon (P = 0.046) and patients (P = 0.025). Further studies may be warranted to better understand the cellular mechanisms leading to Laser-Assisted Skin Healing (LASH).

Gossé, Alban; Iarmarcovai, Gwen; Capon, Alexandre; Cornil, Alain; Mordon, Serge

2009-02-01

335

Optical stimulation of the hearing and deaf cochlea under thermal and stress confinement condition  

NASA Astrophysics Data System (ADS)

There is a controversy, to which extend cochlear stimulation with near infrared laser pulses at a wavelength of 1860 nm is based on optoacoustic stimulation of intact hair cells or -in contrast- is based on direct stimulation of the nerve cells in absence of functional hair cells. Thermal and stress confinement conditions apply, because of the pulse duration range (5 ns, 10 ?s-20 ms) of the two lasers used. The dependency of the signal characteristics on pulse peak power and pulse duration was investigated in this study. The compound action potential (CAP) was measured during stimulation of the cochlea of four anaesthetized guinea pigs, which were hearing at first and afterwards acutely deafened using intracochlear neomycin-rinsing. For comparison hydrophone measurements in a water tank were performed to investigate the optoacoustic signals at different laser interaction regimes. With rising pulse peak power CAPs of the hearing animals showed first a threshold, then a positively correlated and finally a saturating dependency. CAPs also showed distinct responses at laser onset and offset separated with the pulse duration. At pulse durations shorter than physiological response times the signals merged. Basically the same signal characteristics were observed in the optoacoustic hydrophone measurements, scaled with the sensitivity and response time of the hydrophone. Taking together the qualitative correspondence in the signal response and the absence of any CAPs in deafened animals our results speak in favor of an optoacoustic stimulation of intact hair cells rather than a direct stimulation of nerve cells.

Schultz, M.; Baumhoff, P.; Kallweit, N.; Sato, M.; Krüger, A.; Ripken, T.; Lenarz, T.; Kral, A.

2014-03-01

336

Thermal stabilities of drops of burning thermoplastics under the UL 94 vertical test conditions.  

PubMed

The properties of polymer melts will strongly affect the fire hazard of the pool induced by polymer melt flow. In this study the thermal stabilities of eight thermoplastic polymers as well as their melting drops generated under the UL 94 vertical burning test conditions were investigated by thermogravimetric experiments. It was found that the kinetic compensation effect existed for the decomposition reactions of the polymers and their drops. For polymethylmethacrylate (PMMA), high impact polystyrene (HIPS), poly(acrylonitrile-butadiene-styrene) (ABS), polyamide 6 (PA6), polypropylene (PP) and low density polyethylene (LDPE), the onset decomposition temperature and the two decomposition kinetic parameters (the pre-exponential factor and the activation energy) of the drop were less than those of the polymer. However, the onset decomposition temperature and the two kinetic parameters of PC's drop were greater than those of polycarbonate (PC). Interestingly, for polyethylenevinylacetate (EVA18) the drop hardly contained the vinyl acetate chain segments. Similarly, for the PMMA/LDPE blends and the PMMA/PP blends, when the volume fraction of PMMA was less than 50% the drop hardly contained PMMA, implying that the blend would not drip until PMMA burned away and its surface temperature approached the decomposition temperature of the continuous phase composed of LDPE or PP. PMID:23298738

Wang, Yong; Zhang, Jun

2013-02-15

337

Seasonal flows on dark martian slopes, thermal condition for liquescence of salts  

NASA Astrophysics Data System (ADS)

RSLs are narrow, dark albedo features on relatively steep slopes that appear during warm seasons and fade in the cold ones. So far they have only been observed in mid-latitudes where surface temperature is too high, periodically exceeding 300 K, for the presence of shallow ground ice. We attempt to determine what conditions are needed for the liquescence of salt to occur exactly when the RSLs are observed. If the eutectic temperature is exceeded, and humidity is high enough, salts may produce liquid brines through absorption of water vapor and liquescence. We calculate regolith temperature as a function of time and depth, for different macroscopic distributions of salt, for two different microphysical models of the distribution of salt on the regolith grains. Model parameters which are varied include surface albedo, thermal inertia of the dry regolith, the depths at which salt is present, and the salt content. We find that it is possible, for liquescence of magnesium perchlorate to occur where and when RSLs have been observed, but only within a very narrow range of parameters.

Kossacki, Konrad J.; Markiewicz, Wojciech J.

2014-05-01

338

Influence of in-tunnel environment to in-bus air quality and thermal condition in Hong Kong.  

PubMed

In this study, the potential exposure of bus commuters to significant air parameters (CO(2), CO and RSP) and thermal environment (air temperature and relative humidity) when buses traveled through tunnels in Hong Kong was investigated. It was found that air-conditioned buses provided a better commuting environment than non-air-conditioned buses. The blate increasing trend was found on air-conditioned buses as the in-bus air parameters concentration levels rose slowly throughout the traveling process. In contrast, the in-bus environment varied rapidly on non-air-conditioned buses as it depended on the out-bus environment. The measured in-bus CO concentration was 2.9 ppm on air-conditioned buses, while it was 4.6 ppm (even reaching the highest level at 12.0 ppm) on non-air-conditioned buses. Considering the in-bus thermal environment, air-conditioned buses provided thermally comfortable cabins (about 24 degrees C and 59% of relative humidity). However, on non-air-conditioned buses, the thermal environment varied with the out-bus environment. The mean in-bus air temperature was about 34 degrees C and 66% of relative humidity, and the in-bus air temperature varied between 29 and 38 degrees C. Also, the lower-deck to upper-deck air parameters concentration ratios indicated that the vertical dispersion of air pollutants in tunnels influenced non-air-conditioned buses as higher air parameters concentration levels were obtained on the lower-deck cabins. PMID:16084976

Mui, K W; Shek, K W

2005-07-15

339

Recommendations for strengthening the infrared technology component of any condition monitoring program  

NASA Astrophysics Data System (ADS)

This presentation provides insights of a long term 'champion' of many condition monitoring technologies and a Level III infra red thermographer. The co-authors present recommendations based on their observations of infra red and other components of predictive, condition monitoring programs in manufacturing, utility and government defense and energy activities. As predictive maintenance service providers, trainers, informal observers and formal auditors of such programs, the co-authors provide a unique perspective that can be useful to practitioners, managers and customers of advanced programs. Each has over 30 years experience in the field of machinery operation, maintenance, and support the origins of which can be traced to and through the demanding requirements of the U.S. Navy nuclear submarine forces. They have over 10 years each of experience with programs in many different countries on 3 continents. Recommendations are provided on the following: (1) Leadership and Management Support (For survival); (2) Life Cycle View (For establishment of a firm and stable foundation for a program); (3) Training and Orientation (For thermographers as well as operators, managers and others); (4) Analyst Flexibility (To innovate, explore and develop their understanding of machinery condition); (5) Reports and Program Justification (For program visibility and continued expansion); (6) Commitment to Continuous Improvement of Capability and Productivity (Through application of updated hardware and software); (7) Mutual Support by Analysts (By those inside and outside of the immediate organization); (8) Use of Multiple Technologies and System Experts to Help Define Problems (Through the use of correlation analysis of data from up to 15 technologies. An example correlation analysis table for AC and DC motors is provided.); (9) Root Cause Analysis (Allows a shift from reactive to proactive stance for a program); (10) Master Equipment Identification and Technology Application (To place the condition monitoring program in perspective); (11) Use of procedures for Predictive, Condition Monitoring and maintenance in general (To get consistent results); (12) Developing a scheme for predictive, condition monitoring personnel qualification and certification (To provide a career path and incentive to advance skill level and value to the company); (13) Analyst Assignment to Technologies and Related Duties (To make intelligent use of the skills of individuals assigned); (14) Condition Monitoring Analyst Selection Criteria (Key attributes for success are mentioned.); (15) Design and Modification to Support Monitoring (For old and new machinery to facilitate data acquisition); (16) Establishment of a Museum of Components and Samples Pulled from Service for Cause (For orientation and awareness training of operators and managers and exchange of information between analysts); (17) Goals (To promote a proactive program approach for machinery condition improvement).

Nicholas, Jack R., Jr.; Young, R. K.

1999-03-01

340

Energy conversion processes supporting advanced thermal energy storage technologies. [Particle catalyzed solar photodissociation; solid state radiative heat pump  

Microsoft Academic Search

Research that focuses on fundamental aspects of energy conversion could lead to innovative and improved energy storage technologies. Research progress in two energy conversion processes is summarized and the associated storage technologies described. These two processes are particle catalyzed solar photodissociation for thermochemical energy conversion and storage, and the controlled emission of thermal radiation using narrow-bandgap semiconductor materials.

R. J. Otto; P. Berdahl; A. J. Hunt

1986-01-01

341

Magnetohydrodynamic effects on stagnation point flow past a stretching sheet in presence of thermal radiation with convective boundary conditions  

NASA Astrophysics Data System (ADS)

In this study, the mathematical modeling for magnetohydrodynamic effects on stagnation point flow past a stretching sheet in presence of thermal radiation and convective boundary conditions is considered. The transformed boundary layer equations are solved numerically using the Keller-box method. Numerical solutions are obtained for the local heat transfer coefficient, the surface temperature as well as the temperature profiles. The features of the flow and heat transfer characteristics for various values of the Prandtl number, stretching parameter, magnetic parameter, thermal radiation parameter and conjugate parameter are analyzed and discussed. In conclusion, the thermal boundary layer thickness depends strongly on these five parameters. It is found that, as Prandtl number, stretching parameter and thermal radiation parameter increase, the temperature profiles decrease. While, as magnetic parameter and conjugate parameter increase, the temperature profiles also increase.

Mohamed, M. K. A.; Anwar, M. I.; Shafie, S.; Salleh, M. Z.; Ishak, A.

2013-04-01

342

A novel test approach for plasma-sprayed coatings tested simultaneously under CMAS and thermal gradient cycling conditions  

Microsoft Academic Search

Plasma-sprayed ceramic coatings, used as thermal barrier or abradable coatings in high-pressure stages of gas turbines, are exposed to high thermo-mechanical loading due to harsh operating conditions. Under certain conditions they also have to withstand attack by calcium-magnesium-alumino-silicate (CMAS) deposits resulting from the ingestion of siliceous minerals with the intake air.Resistance to this kind of attack becomes more important at

Tanja Steinke; Doris Sebold; Daniel E. Mack; Robert Vaßen; Detlev Stöver

2010-01-01

343

Characteristics of the boundary layer with hydrogen combustion with variations of thermal conditions on a permeable wall  

Microsoft Academic Search

The paper describes a numerical study of the influence of thermal and boundary conditions on the structure of laminar and\\u000a turbulent diffusion flames in the cases with hydrogen injection through a porous surface and with hydrogen combustion in an\\u000a air flow. Two types of boundary conditions are compared: with a given constant temperature T\\u000a \\u000a w\\u000a = const over the length

É. P. Volchkov; V. V. Terekhov; V. I. Terekhov

2009-01-01

344

Non-thermal plasma based technologies for the after-treatment of automotive exhaust particulates and marine diesel exhaust NOx  

SciTech Connect

The trend in environmental legislation is such that primary engine modifications will not be sufficient to meet all future emissions requirements and exhaust aftertreatment technologies will need to be employed. One potential solution that is well placed to meet those requirements is non-thermal plasma technology. This paper will describe our work with some of our partners in the development of a plasma based diesel particulate filter (DPF) and plasma assisted catalytic reduction (PACR) for NOx removal. This paper describes the development of non-thermal plasma technology for the aftertreatment of particulates from a passenger car engine and NOx from a marine diesel exhaust application.

McAdams, R; Beech, P; Gillespie, R; Guy, C; Jones,S; Liddell, T; Morgan, R; Shawcross, J; Weeks, D; Hughes, D; Oesterle, J; Eberspdcher,

2003-08-24

345

Influence of deposition conditions on the morphology and phase of tungsten oxide nanorods synthesized by thermal oxidation  

Microsoft Academic Search

When synthesizing tungsten oxide nanorods using thermal oxidation, the deposition conditions play an important role in the\\u000a morphology and phase structure. The evaporation voltage greatly influences the average diameter of the nanorods. The evaporation\\u000a time controls the deposit thickness, while the deposition temperature determines the phase structure.

Floriane Galléa; Zhengcao Li; Zhengjun Zhang

2007-01-01

346

Shallow Thermal Conditions in the Central and Southern Cascadia Subduction Zone J.R. McKenna1  

E-print Network

Shallow Thermal Conditions in the Central and Southern Cascadia Subduction Zone J.R. McKenna1 and D quiescent central and southern Cascadia subduction zone (CSZ) to gain insight into hypothesized great (Mw. The anomalous character of the Cascadia Subduction Zone (CSZ) is immediately obvious because, based

Southern Methodist University

347

Calculation and visual displaying of the water chemistry conditions in return cooling systems at thermal power stations  

NASA Astrophysics Data System (ADS)

Matters concerned with treatment of cooling water at thermal power stations are addressed. Problems arising during operation of return cooling systems equipped with cooling towers are analyzed. The software used for monitoring, control, and indication of the hydraulic and water chemistry operating conditions of the circulation system at the Yaivinsk district power station is considered.

Ochkov, V. F.; Orlov, K. A.; Ivanov, E. N.; Makushin, A. A.

2013-07-01

348

Increasing Heavy Oil Reserves in the Wilmington Oil Field Through Advanced Reservoir Characterization and Thermal Production Technologies, Class III  

SciTech Connect

The objective of this project was to increase the recoverable heavy oil reserves within sections of the Wilmington Oil Field, near Long Beach, California through the testing and application of advanced reservoir characterization and thermal production technologies. The successful application of these technologies would result in expanding their implementation throughout the Wilmington Field and, through technology transfer, to other slope and basin clastic (SBC) reservoirs.

City of Long Beach; Tidelands Oil Production Company; University of Southern California; David K. Davies and Associates

2002-09-30

349

Increasing Heavy Oil Reserves in the Wilmington Oil Field Through Advanced Reservoir Characterization and Thermal Production Technologies, Class III  

SciTech Connect

The objective of this project was to increase the recoverable heavy oil reserves within sections of the Wilmington Oil Field, near Long Beach, California through the testing and application of advanced reservoir characterization and thermal production technologies. It was hoped that the successful application of these technologies would result in their implementation throughout the Wilmington Field and, through technology transfer, will be extended to increase the recoverable oil reserves in other slope and basin clastic (SBC) reservoirs.

City of Long Beach; Tidelands Oil Production Company; University of Southern California; David K. Davies and Associates

2002-09-30

350

Assessment of the State of the Art of Flight Control Technologies as Applicable to Adverse Conditions  

NASA Technical Reports Server (NTRS)

Literature from academia, industry, and other Government agencies was surveyed to assess the state of the art in current Integrated Resilient Aircraft Control (IRAC) aircraft technologies. Over 100 papers from 25 conferences from the time period 2004 to 2009 were reviewed. An assessment of the general state of the art in adaptive flight control is summarized first, followed by an assessment of the state of the art as applicable to 13 identified adverse conditions. Specific areas addressed in the general assessment include flight control when compensating for damage or reduced performance, retrofit software upgrades to flight controllers, flight control through engine response, and finally test and validation of new adaptive controllers. The state-of-the-art assessment applicable to the adverse conditions include technologies not specifically related to flight control, but may serve as inputs to a future flight control algorithm. This study illustrates existing gaps and opportunities for additional research by the NASA IRAC Project

Reveley, Mary s.; Briggs, Jeffrey L.; Leone, Karen M.; Kurtoglu, Tolga; Withrow, Colleen A.

2010-01-01

351

Development of air conditioning technologies to reduce CO2 emissions in the commercial sector  

PubMed Central

Background Architectural methods that take into account global environmental conservation generally concentrate on mitigating the heat load of buildings. Here, we evaluate the reduction of carbon dioxide (CO2) emissions that can be achieved by improving heating, ventilating, and air conditioning (HVAC) technologies. Results The Climate Change Research Hall (CCRH) of the National Institute for Environmental Studies (NIES) is used as a case study. CCRH was built in line with the "Green Government Buildings" program of the Government Buildings Department at the Ministry of Land, Infrastructure and Transport in Japan. We have assessed the technology used in this building, and found that there is a possibility to reduce energy consumption in the HVAC system by 30%. Conclusion Saving energy reduces CO2 emissions in the commercial sector, although emission factors depend on the country or region. Consequently, energy savings potential may serve as a criterion in selecting HVAC technologies with respect to emission reduction targets. PMID:17062161

Yoshida, Yukiko

2006-01-01

352

Influence of free edge intralaminar stresses on damage process in CFRP laminates under thermal cycling conditions  

Microsoft Academic Search

The purpose of this study is to understand the damage mechanisms of CFRP laminate subjected to repeated thermo-mechanical loads. Thermal cycling tests in oxygen show that the oxidation at high temperature associated with the “fatigue” phenomenon due to the cyclic thermal stresses lead to many matrix cracks. By means of optical microscopy and X-ray technique, some observations permit to characterize

M. C. Lafarie-Frenot; N. Q. Ho

2006-01-01

353

Ground thermal conditions and active layer processes within two glacier forefields with heterogeneous permafrost occurrence  

NASA Astrophysics Data System (ADS)

The patchy occurrence of frozen ground in the alpine discontinuous permafrost zone is well known and often restricted to block fields and areas with coarse surface substrate. External factors that account for this heterogeneous distribution on a local scale are snow depth, snow cover evolution, local topography, nature of substrate and glacial history. We present temperature and geoelectrical monitoring data from two glacier forefields in the Swiss Alps, both deglaciated since the Little Ice Age. Two boreholes were drilled in 2006 at Val Murgal (8 m) and another two in 2008 within glacier forefield Vadret dal Murtèl (10 m) each equipped with temperature sensors in variable depths. Additionally, temperature data loggers were placed at both sites. Boreholes and miniloggers were installed at locations with different substrate to cover the range in grain sizes from sand to boulders that dominate in this kind of alpine environment. Geoelectrical measurements were conducted across the boreholes to correlate thermal conditions with physical properties of the near surface layer. Whereas in Val Muragl measurements were repeated several times a year since 2005, an automatic monitoring was installed in March 2011 in glacier forefield Murtèl. With the monitoring system changes in subsurface electrical resistivity can be resolved on a diurnal scale. Together with borehole temperatures these data enhance the understanding of processes during snow melt in spring and freeze-back in autumn within the active layer. Temperature data show a constant depth of the active layer for the 6-year record of Val Muragl. While the blocky debris thaws down to 2 m during summer, the active layer is 5 m at the site with finer till. A contrary trend is visible at the lowermost sensor in 8 m depth that indicates a slight warming at the coarse site. Within the fine debris temperatures dropped from -0.3 °C to -0.7 °C since 2009 and at the same time the annual signal diminished. The 3-year record from Murtèl site shows a constant temperature slightly below the freezing point at the 10 m sensor without any trend at the blocky site. The second borehole in morainic till has seasonal frost conditions. Data from miniloggers document a strong heterogeneity in the thermal regime at the ground surface on a local scale. Mean annual ground surface temperatures differ by more than 3 °C within short distances and show a correlation with grain size. However, outliers with cold MAGST indicate that permafrost may exist even at sites with finer debris. Results from geoelectrical measurements indicate a fast reduction in ground resistivity within the active layer that occurs immediately when the snow cover gets isothermal and snow melt sets in. Resistivity values decreased by more than 60 per cent during a 6 day period in May 2011.

Rödder, T.; Kneisel, C.

2012-04-01

354

Remote Sensing of In-Flight Icing Conditions: Operational, Meteorological, and Technological Considerations  

NASA Technical Reports Server (NTRS)

Remote-sensing systems that map aircraft icing conditions in the flight path from airports or aircraft would allow icing to be avoided and exited. Icing remote-sensing system development requires consideration of the operational environment, the meteorological environment, and the technology available. Operationally, pilots need unambiguous cockpit icing displays for risk management decision-making. Human factors, aircraft integration, integration of remotely sensed icing information into the weather system infrastructures, and avoid-and-exit issues need resolution. Cost, maintenance, power, weight, and space concern manufacturers, operators, and regulators. An icing remote-sensing system detects cloud and precipitation liquid water, drop size, and temperature. An algorithm is needed to convert these conditions into icing potential estimates for cockpit display. Specification development requires that magnitudes of cloud microphysical conditions and their spatial and temporal variability be understood at multiple scales. The core of an icing remote-sensing system is the technology that senses icing microphysical conditions. Radar and microwave radiometers penetrate clouds and can estimate liquid water and drop size. Retrieval development is needed; differential attenuation and neural network assessment of multiple-band radar returns are most promising to date. Airport-based radar or radiometers are the most viable near-term technologies. A radiometer that profiles cloud liquid water, and experimental techniques to use radiometers horizontally, are promising. The most critical operational research needs are to assess cockpit and aircraft system integration, develop avoid-and-exit protocols, assess human factors, and integrate remote-sensing information into weather and air traffic control infrastructures. Improved spatial characterization of cloud and precipitation liquid-water content, drop-size spectra, and temperature are needed, as well as an algorithm to convert sensed conditions into a measure of icing potential. Technology development also requires refinement of inversion techniques. These goals can be accomplished with collaboration among federal agencies including NASA, the FAA, the National Center for Atmospheric Research, NOAA, and the Department of Defense. This report reviews operational, meteorological, and technological considerations in developing the capability to remotely map in-flight icing conditions from the ground and from the air.

Ryerson, Charles C.

2000-01-01

355

Potential Applications of Concentrated Solar Thermal Technologies in the Australian Minerals Processing and Extractive Metallurgical Industry  

NASA Astrophysics Data System (ADS)

The Australian minerals processing and extractive metallurgy industries are responsible for about 20% of Australia's total greenhouse gas (GHG) emissions. This article reviews the potential applications of concentrated solar thermal (CST) energy in the Australian minerals processing industry to reduce this impact. Integrating CST energy into these industries would reduce their reliance upon conventional fossil fuels and reduce GHG emissions. As CST technologies become more widely deployed and cheaper, and as fuel prices rise, CST energy will progressively become more competitive with conventional energy sources. Some of the applications identified in this article are expected to become commercially competitive provided the costs for pollution abatement and GHG mitigation are internalized. The areas of potential for CST integration identified in this study can be classed as either medium/low-temperature or high-temperature applications. The most promising medium/low-grade applications are electricity generation and low grade heating of liquids. Electricity generation with CST energy—also known as concentrated solar power—has the greatest potential to reduce GHG emissions out of all the potential applications identified because of the 24/7 dispatchability when integrated with thermal storage. High-temperature applications identified include the thermal decomposition of alumina and the calcination of limestone to lime in solar kilns, as well as the production of syngas from natural gas and carbonaceous materials for various metallurgical processes including nickel and direct reduced iron production. Hybridization and integration with thermal storage could enable CST to sustain these energy-intensive metallurgical processes continuously. High-temperature applications are the focus of this paper.

Eglinton, Thomas; Hinkley, Jim; Beath, Andrew; Dell'Amico, Mark

2013-12-01

356

Analytical Solution of Thermal Wave Models on Skin Tissue Under Arbitrary Periodic Boundary Conditions  

NASA Astrophysics Data System (ADS)

Modeling and understanding the heat transfer in biological tissues is important in medical thermal therapeutic applications. The biothermomechanics of skin involves interdisciplinary features, such as bioheat transfer, biomechanics, and burn damage. The hyperbolic thermal wave model of bioheat transfer and the parabolic Pennes bioheat transfer equations with blood perfusion and metabolic heat generation are applied for the skin tissue as a finite and semi-infinite domain when the skin surface temperature is suddenly exposed to a source of an arbitrary periodic temperature. These equations are solved analytically by Laplace transform methods. The thermal wave model results indicate that a non-Fourier model has predicted the thermal behavior correctly, compared to that of previous experiments. The results of the thermal wave model show that when the first thermal wave moves from the first boundary, the temperature profiles for finite and semi-infinite domains of skin become separated for these phenomena; the discrepancy between these profiles is negligible. The accuracy of the obtained results is validated through comparisons with existing numerical results. The results demonstrate that the non-Fourier model is significant in describing the thermal behavior of skin tissue.

Fazlali, R.; Ahmadikia, H.

2013-01-01

357

Influence of heatsink from upper boundary on the industrial premises thermal conditions at gas infrared emitter operation  

NASA Astrophysics Data System (ADS)

The results of mathematical simulation of the heat transfer processes in the closed domain, which corresponds to production accomodation with the gas infrared emitter operation condition are presented. The system of differential Navier-Stokes equations in the approximation of Boussinesq is solved. The comparative analysis of thermal conditions formation in the closed domain is carried out taking into account heat withdrawal through the upper enclosing construction and under the conditions of its heat insulation. The essential transiency of the analyzed heat transfer process and the influence of heat withdrawal from one of the outer boundaries on the mean temperatures values in large-dimension industrial premises are established.

Maksimov, Vyacheslav I.; Nagornova, Tatiana A.

2014-08-01

358

Investigation of Thermal Stress Convection in Nonisothermal Gases under Microgravity Conditions  

NASA Technical Reports Server (NTRS)

The project has sought to ascertain the veracity of the Burnett relations, as applied to slow moving, highly nonisothermal gases, by comparison of convection and stress predictions with those generated by the DSMC method. The Burnett equations were found to provide reasonable descriptions of the pressure distribution and normal stress in stationary gases with a 1-D temperature gradient. Continuum/Burnett predictions of thermal stress convection in 2-D heated enclosures, however, are not quantitatively supported by DSMC results. For such situations, it appears that thermal creep flows, generated at the boundaries of the enclosure, will be significantly larger than the flows resulting from thermal stress in the gas.

Mackowski, Daniel W.

1999-01-01

359

Thermal conductivity of vertically aligned carbon nanotube arrays: Growth conditions and tube inhomogeneity  

NASA Astrophysics Data System (ADS)

The thermal conductivity of vertically aligned carbon nanotube arrays (VACNTAs) grown on silicon dioxide substrates via chemical vapor deposition is measured using a 3? technique. For each sample, the VACNTA layer and substrate are pressed to a heating line at varying pressures to extract the sample's thermophysical properties. The nanotubes' structure is observed via transmission electron microscopy and Raman spectroscopy. The presence of hydrogen and water vapor in the fabrication process is tuned to observe the effect on measured thermal properties. The presence of iron catalyst particles within the individual nanotubes prevents the array from achieving the overall thermal conductivity anticipated based on reported measurements of individual nanotubes and the packing density.

Bauer, Matthew L.; Pham, Quang N.; Saltonstall, Christopher B.; Norris, Pamela M.

2014-10-01

360

Robust vehicle detection under various environmental conditions using an infrared thermal camera and its application to road traffic flow monitoring.  

PubMed

We have already proposed a method for detecting vehicle positions and their movements (henceforth referred to as "our previous method") using thermal images taken with an infrared thermal camera. Our experiments have shown that our previous method detects vehicles robustly under four different environmental conditions which involve poor visibility conditions in snow and thick fog. Our previous method uses the windshield and its surroundings as the target of the Viola-Jones detector. Some experiments in winter show that the vehicle detection accuracy decreases because the temperatures of many windshields approximate those of the exterior of the windshields. In this paper, we propose a new vehicle detection method (henceforth referred to as "our new method"). Our new method detects vehicles based on tires' thermal energy reflection. We have done experiments using three series of thermal images for which the vehicle detection accuracies of our previous method are low. Our new method detects 1,417 vehicles (92.8%) out of 1,527 vehicles, and the number of false detection is 52 in total. Therefore, by combining our two methods, high vehicle detection accuracies are maintained under various environmental conditions. Finally, we apply the traffic information obtained by our two methods to traffic flow automatic monitoring, and show the effectiveness of our proposal. PMID:23774988

Iwasaki, Yoichiro; Misumi, Masato; Nakamiya, Toshiyuki

2013-01-01

361

Forced convection of gaseous slip-flow in porous micro-channels under Local Thermal Non-Equilibrium conditions  

Microsoft Academic Search

Steady laminar forced convection gaseous slip-flow through parallel-plates micro-channel filled with porous medium under Local\\u000a Thermal Non-Equilibrium (LTNE) condition is studied numerically. We consider incompressible Newtonian gas flow, which is hydrodynamically\\u000a fully developed while thermally is developing. The Darcy–Brinkman–Forchheimer model embedded in the Navier–Stokes equations\\u000a is used to model the flow within the porous domain. The present study reports the

O. M. Haddad; M. A. Al-Nimr; J. Sh. Al-Omary

2007-01-01

362

Study on the Technology and Method of Land Cover Classification for Geographic National Conditions Surveying  

NASA Astrophysics Data System (ADS)

Land Cover is the basis of geographic national conditions monitoring, extracting land cover information timely and accurately has become one of important tasks in the geographic national conditions surveying project. For the current situation of complex land cover type and large amount of data, there has emerged various new classification techniques and methods. However, the big difficult of classification?the large amount of data, the heavy workload of post-editing and other factors have seriously hampered the progress of the project. In this paper, it chooses high-resolution remote sensing image as original data, comprehensivly elaborates present research situation of oriented land cover classification. By the systematical analysis and summary of the basic and key problems of the land cover classification technology, relying on the geographic national information classification and standard system, discusses the available methods preliminarily to improve the accuracy of land cover classification which based on geographic national conditions surveying.

Jia, Y.; Li, H. T.; Gu, H. Y.; Han, Y. S.

2013-07-01

363

Turonian Ultra-thermal Conditions as Recorded in the High Canadian Arctic: Faunal Controls and Tectomagmatic Boundary Conditions  

NASA Astrophysics Data System (ADS)

Fossil vertebrate discoveries in the High Canadian Arctic over the last decade are reviewed here. These have defined an interval of extreme climatic warmth in the Arctic region during Turonian (ca 90 Ma) times. The discussion is broadened to include a review of Arctic tectonic and magmatic conditions during the Late Cretaceous, and will include an outline of work to further refine paleotemperature estimates. The discovery of fossil champsosaurs from sedimentary rocks of Axel Heiberg Island suggested a minimum mean annual temperature of 14 degrees C (Tarduno et. al., 1998) when paleomagnetic data indicate that the site was at Arctic paleolatitudes (Tarduno et al., 2002). Work conducted on several faunal groups support the initial report of warm conditions. Fish fossils record an expansion of ranges toward the poles (Friedman et al., 2003), whereas turtle diversity is unusually high, consistent with warm temperatures (Brinkman and Tarduno, 2005). The fossil champsosaurs define a population dominated by juveniles, incompatible with cold conditions (Vandermark et al., 2007). Aurorachelys gaffneyi, a large macrobaenid fossil turtle with affinities to Asia, suggests the possibility of migration over a warm brackish Arctic Ocean, possibly dotted with islands related to unusually vigorous magmatic activity (Vandermark et al., 2009). The fossil vertebrates were found in sedimentary rocks overlying continental flood basalts of the Strand Fiord Formation, which may be the onland expression of magmatism that formed Alpha Ridge of the Arctic Ocean. If correct, CO2 outgassing related to this volcanism, together with outgassing at several other sites of coeval magmatism, may have been responsible for the interval of extreme climatic warmth.

Bono, R.; Tarduno, J. A.; Cottrell, R. D.; Higgins, P.; Brinkman, D. B.

2010-12-01

364

Measurements of nuclear thermal relaxation times under conditions of high resolution  

E-print Network

. . . ?0 TABLE OF CONTENTS CHAPTER PAGE V. DATA AND RESULTS (continued) Thermal Relaxation Times of Proton Groups in Pure Organic Liquids.................... 51 Variation of the Relaxation Time with Dilution............ .................. M VI.... Graphical method used to determine the relaxation time T ^ .................... .. . **9 3. Variation of the reciprocal of the thermal relaxation time of the methyl and ring protons of toluene in carbon disulfide. . . . 59 LIST OF TABLES TABLES PAGE 1...

Hildebrandt, Alvin Frank

2013-10-04

365

Kinetic calculations for the thermal decomposition of calcium propionate under non-isothermal conditions  

Microsoft Academic Search

Calcium propionate (CP) is shown to be useful for simultaneous SO2\\/NO reduction in coal-fired power plants and its thermal decomposition characteristics are measured by thermogravimetric analysis\\u000a in a feasibility study into more complete reduction of these hazardous gases. Calcium carbonate (CC), which has been used\\u000a primarily for in-furnace desulfuration, was used for comparison. The thermal decomposition of this organic calcium-based

ShengLi Niu; KuiHua Han; ChunMei Lu

2011-01-01

366

Numerical simulations of heat and moisture transport in thermal protective clothing under flash fire conditions.  

PubMed

A numerical model of heat and moisture transport in thermal protective clothing during exposure to a flash fire was introduced. The model was developed with the assumption that textiles are treated as porous media. The numerical model predictions were compared with experimental data from different fabric systems and configurations. Additionally, with the introduction of a skin model, the parameters that affect the performance of thermal protective clothing were investigated. PMID:18394330

Song, Guowen; Chitrphiromsri, Patirop; Ding, Dan

2008-01-01

367

Study over thermal state of gas turbine engine metal-ceramic rotor blades and nozzle guide vanes under thermal shock and thermal-cyclic loading conditions  

NASA Astrophysics Data System (ADS)

To ensure a reliable operation of the 2.5 MW gas turbine engine (GTE- 2.5)[1] with the inlet gas temperature TIT=1623 K, studies were performed over the thermal state of the nozzle guide vanes and rotor blades with the temperatures, rates and flows of the working media and cooling air simulating all the potential turbine stage operating duties. The steady state and thermal-cyclic tests having been accomplished, there was no visible defect on the rotor blades and the nozzle vanes. Afterwards, they survived the endurance tests at the rated cooling. Therefore, the functionality of the shell thin-wall hybrid nozzle vanes and rotor blades under the variable operating duties of the gas turbine at the “shock” and “cyclic” loads of the working media temperature variations has been demonstrated.

Soudarev, A. V.; Souryaninov, A. A.; Podgorets, V. Ya.; Grishaev, V. V.; Tikhoplav, V. Yu; Molchanov, A. S.; Soudarev, B. V.

2004-05-01

368

Solar thermal technology development: Estimated market size and energy cost savings. Volume 1: Executive summary  

NASA Astrophysics Data System (ADS)

Estimated future energy cost savings associated with the development of cost-competitive solar thermal technologies (STT) are discussed. Analysis is restricted to STT in electric applications for 16 high-insolation/high-energy-price states. The fuel price scenarios and three 1990 STT system costs are considered, reflecting uncertainty over future fuel prices and STT cost projections. STT R&D is found to be unacceptably risky for private industry in the absence of federal support. Energy cost savings were projected to range from $0 to $10 billion (1990 values in 1981 dollars), dependng on the system cost and fuel price scenario. Normal R&D investment risks are accentuated because the Organization of Petroleum Exporting Countries (OPEC) cartel can artificially manipulate oil prices and undercut growth of alternative energy sources. Federal participation in STT R&D to help capture the potential benefits of developing cost-competitive STT was found to be in the national interest.

Gates, W. R.

1983-02-01

369

Potential impact of ZT = 4 thermoelectric materials on solar thermal energy conversion technologies.  

PubMed

State-of-the-art methodologies for the conversion of solar thermal power to electricity are based on conventional electromagnetic induction techniques. If appropriate ZT = 4 thermoelectric materials were available, it is likely that conversion efficiencies of 30-40% could be achieved. The availability of all solid state electricity generation would be a long awaited development in part because of the elimination of moving parts. This paper presents a preliminary examination of the potential performance of ZT = 4 power generators in comparison with Stirling engines taking into account specific mass, volume and cost as well as system reliability. High-performance thermoelectrics appear to have distinct advantages over magnetic induction technologies. PMID:20196558

Xie, Ming; Gruen, Dieter M

2010-11-18

370

Building America Best Practices Series, Volume 6: High-Performance Home Technologies: Solar Thermal & Photovoltaic Systems  

SciTech Connect

This guide is was written by PNNL for the US Department of Energy's Building America program to provide information for residential production builders interested in building near zero energy homes. The guide provides indepth descriptions of various roof-top photovoltaic power generating systems for homes. The guide also provides extensive information on various designs of solar thermal water heating systems for homes. The guide also provides construction company owners and managers with an understanding of how solar technologies can be added to their homes in a way that is cost effective, practical, and marketable. Twelve case studies provide examples of production builders across the United States who are building energy-efficient homes with photovoltaic or solar water heating systems.

Baechler, Michael C.; Gilbride, Theresa L.; Ruiz, Kathleen A.; Steward, Heidi E.; Love, Pat M.

2007-06-04

371

A new 3He-free thermal neutrons detector concept based on the GEM technology  

NASA Astrophysics Data System (ADS)

A thermal neutron detector based on the Gas Electron Multiplier technology is presented. It is configured to let a neutron beam interact with a series of borated glass layers placed in sequence along the neutron path inside the device. The detector has been tested on beam both at the ISIS (UK) spallation neutron source and at the TRIGA reactor of ENEA, at the Casaccia Research Center, near Rome in Italy. For a complete characterization and description of the physical mechanism underlying the detector operation, several Monte Carlo simulations were performed using both Fluka and Geant4 code. These simulations are intended to help in seeking the optimal geometrical set-up and material thickness (converter layer, gas gap, sheet substrate) to improve the final detector design in terms of achieving the best detector efficiency possible.

Pietropaolo, A.; Murtas, F.; Claps, G.; Quintieri, L.; Raspino, D.; Celentano, G.; Vannozzi, A.; Frasciello, O.

2013-11-01

372

Plasticity of the thermal requirements of exotherms and adaptation to environmental conditions  

PubMed Central

In exothermal organisms, temperature is an important determinant of the rate of ecophysiological processes, which monotonically increase between the minimum (td min) and maximum (td max) temperatures typical for each species. In insects, td min and td max are correlated and there is a approximately 20°C interval (thermal window WT = td max ? td min) between them over which insects can develop. We assumed that other exotherms have similar thermal windows because the thermal kinetics of their physiological processes are similar. In this study, we determined the thermal requirements for germination in plants. Seeds of 125 species of Central European wild herbaceous and crop plants were germinated at nine constant temperatures between 5 and 37°C, and the time to germination of 50% of the seeds D and rate of germination R (=1/D) were determined for each temperature and the Lactin model used to determine td min, td max, and WT. The average width of the thermal windows for seeds was significantly wider (mean 24°C, 95% CI 22.7–24.2°C), varied more (between 14.5 and 37.5°C) and development occurred at lower temperatures than recorded for insects. The limiting temperatures for germination, td min and td max, were not coupled, so the width of the thermal window increased with both a decrease in td min and/or increase in td max. Variation in WT was not associated with taxonomic affiliation, adult longevity, or domestication of the different species, but tends to vary with seed size. Plants are poor at regulating their temperature and cannot move to a more suitable location and as a consequence have to cope with wider ranges in temperatures than insects and possibly do this by having wider thermal windows. Synthesis: The study indicated specificity of WT in different exotherm taxa and/or their development stages. PMID:25247067

Honek, Alois; Martinkova, Zdenka; Lukas, Jan; Dixon, Anthony F G

2014-01-01

373

Assessment of thermal load on transported goats administered with ascorbic acid during the hot-dry conditions  

NASA Astrophysics Data System (ADS)

The major factor in the induction of physiological stress during road transportation of livestock is the complex fluctuations of the thermal transport microenvironment, encountered when animals are transported across different ecological zones. Recommended guidelines on optimum "on-board" conditions in which goats should be transported are lacking, and there are no acceptable ranges and limits for the thermal loads to which goats may be subjected during long-distance road transportation in hot-dry conditions. Panting score (PS), rectal temperature (RT), heart rate (HR) and respiratory rate (RR) were employed as reliable stress indices to assess the effects of different thermal loads, measured as temperature humidity index (THI), encountered in the vehicle during 12 h of road transportation of 40 goats, and to suggest the administration of 100 mg/kg body weight of ascorbic acid (AA) as an ameliorating agent. The results obtained showed that the PS, RT, HR and RR rose above normal reference values with increase in the THI and journey duration. The rise in PS value, which is a visual indicator of the severity of thermal load, was the most pronounced. The results suggest that values of THI in the vehicle up to 94.6 constitute no risk, while at of 100 it presents a moderate risk and above 100 may result in severe stress. The relationships between the thermal load and the physiological variables were positive and significant ( P < 0.05). They reflect the degree of stress imposed by each THI value during the transportation, and may be used as recommended ranges and limit thermal load values in transported goats. The results demonstrated that administration of 100 mg/kg body weight of AA before road transportation mitigated the risk of adverse effects of high THI values and other stress factors due to road transportation in goats.

Minka, N. S.; Ayo, J. O.

2012-03-01

374

Infrared thermal wave nondestructive technology on the defect in the shell of solid rocket motor  

NASA Astrophysics Data System (ADS)

Based on the active infrared thermography nondestructive testing (NDT) technology, which is an emerging method and developed in the areas of aviation, spaceflight and national defence, the samples including glass fiber flat bottom hole sample, glass fiber inclusion sample and steel flat bottom hole sample that the shell materials of Solid Rocket Motor (SRM) were heated by a high energy flash lamp. The subsurface flaws can be detected through measuring temperature difference between flaws and materials. The results of the experiments show that: 1) the technique is a fast and effective inspection method, which is used for detecting the composites more easily than the metals. And it also can primarily identify the defect position and size according to the thermal image maps. 2) A best inspection time at when the area of hot spot is the same with that of defect is exited, which can be used to estimate the defect size. The bigger the defect area, the easier it could be detected and also the less of the error for estimating defect area. 3). The infrared thermal images obtained from experiments always have high noise, especially for metal materials due to high reflectivity and environmental factors, which need to be further processed.

Zhang, Wei; Song, Yuanjia; Yang, Zhengwei; Li, Ming; Tian, Gan

2010-10-01

375

Survey of the supporting research and technology for the thermal protection of the Galileo Probe  

NASA Technical Reports Server (NTRS)

The Galileo Probe, which is scheduled to be launched in 1985 and to enter the hydrogen-helium atmosphere of Jupiter up to 1,475 days later, presents thermal protection problems that are far more difficult than those experienced in previous planetary entry missions. The high entry speed of the Probe will cause forebody heating rates orders of magnitude greater than those encountered in the Apollo and Pioneer Venus missions, severe afterbody heating from base-flow radiation, and thermochemical ablation rates for carbon phenolic that rival the free-stream mass flux. This paper presents a comprehensive survey of the experimental work and computational research that provide technological support for the Probe's heat-shield design effort. The survey includes atmospheric modeling; both approximate and first-principle computations of flow fields and heat-shield material response; base heating; turbulence modelling; new computational techniques; experimental heating and materials studies; code validation efforts; and a set of 'consensus' first-principle flow-field solutions through the entry maneuver, with predictions of the corresponding thermal protection requirements.

Howe, J. T.; Pitts, W. C.; Lundell, J. H.

1981-01-01

376

The small community solar thermal power experiment. Parabolic dish technology for industrial process heat application  

NASA Technical Reports Server (NTRS)

Aspects of incorporating a thermal energy transport system (ETS) into a field of parabolic dish collectors for industrial process heat (IPH) applications were investigated. Specific objectives are to: (1) verify the mathematical optimization of pipe diameters and insulation thicknesses calculated by a computer code; (2) verify the cost model for pipe network costs using conventional pipe network construction; (3) develop a design and the associated production costs for incorporating risers and downcomers on a low cost concentrator (LCC); (4) investigate the cost reduction of using unconventional pipe construction technology. The pipe network design and costs for a particular IPH application, specifically solar thermally enhanced oil recovery (STEOR) are analyzed. The application involves the hybrid operation of a solar powered steam generator in conjunction with a steam generator using fossil fuels to generate STEOR steam for wells. It is concluded that the STEOR application provides a baseline pipe network geometry used for optimization studies of pipe diameter and insulation thickness, and for development of comparative cost data, and operating parameters for the design of riser/downcomer modifications to the low cost concentrator.

Polzien, R. E.; Rodriguez, D.

1981-01-01

377

Analytical Predictions of Thermal Stress in the Stardust PICA Heatshield Under Reentry Flight Conditions  

NASA Technical Reports Server (NTRS)

We performed finite element analyses on a model of the Phenolic Impregnated Carbon Ablator (PICA) heatshield from the Stardust sample return capsule (SRC) to predict the thermal stresses in the PICA material during reentry. The heatshield on the Stardust SRC was a 0.83 m sphere cone, fabricated from a single piece of 5.82 cm-thick PICA. The heatshield performed successfully during Earth reentry of the SRC in January 2006. Material response analyses of the full, axisymmetric PICA heatshield were run using the Two-Dimensional Implicit Ablation, Pyrolysis, and Thermal Response Program (TITAN). Peak surface temperatures were predicted to be 3385K, while the temperature at the PICA backface remained at the estimated initial cold-soak temperature of 278K. Surface recession and temperature distribution results from TITAN, at several points in the reentry trajectory, were mapped onto an axisymmetric finite element model of the heatshield. We used the finite element model to predict the thermal stresses in the PICA from differential thermal expansion. The predicted peak compressive stress in the PICA heatshield was 1.38 MPa. Although this level of stress exceeded the chosen design limit for compressive stresses in PICA tiles for the design of the Orion crew exploration vehicle heatshield, the Stardust heatshield exhibited no obvious mechanical failures from thermal stress. The analyses of the Stardust heatshield were used to assess and adjust the level of conservatism in the finite element analyses in support of the Orion heatshield design.

Squire, Thomas; Milos, Frank; Agrawal, Parul

2009-01-01

378

Study Task for Determining the Effects of Boost-Phase Environments on Densified Propellants Thermal Conditions for Expendable Launch Vehicles  

NASA Technical Reports Server (NTRS)

A thermodynamic study has been conducted that investigated the effects of the boost-phase environment on densified propellant thermal conditions for expendable launch vehicles. Two thermodynamic models were developed and utilized to bound the expected thermodynamic conditions inside the cryogenic liquid hydrogen and oxygen propellant tanks of an Atlas IIAS/Centaur launch vehicle during the initial phases of flight. The ideal isentropic compression model was developed to predict minimum pressurant gas requirements. The thermal equilibrium model was developed to predict the maximum pressurant gas requirements. The models were modified to simulate the required flight tank pressure profiles through ramp pressurization, liquid expulsion, and tank venting. The transient parameters investigated were: liquid temperature, liquid level, and pressurant gas consumption. Several mission scenarios were analyzed using the thermodynamic models, and the results indicate that flying an Atlas IIAS launch vehicle with densified propellants is feasible and beneficial but may require some minor changes to the vehicle.

Haberbusch, Mark S.; Meyer, Michael L. (Technical Monitor)

2002-01-01

379

Power conditioning subsystems for photovoltaic central-station power plants - Technology and performance  

NASA Technical Reports Server (NTRS)

Central-Station (CS) Photovoltaic (PV) systems have the potential of economically displacing significant amounts of centrally generated electricity. However, the technical viability and, to some extent, the economic viability of central-station PV generation technology will depend upon the availability of large power conditioners that are efficient, safe, reliable, and economical. This paper is an overview of the technical and cost requirements that must be met to develop economically viable power conditioning subsystems (PCS) for central-station power plants. The paper also examines various already commercially available PCS hardware that may be suitable for use in today's central PV power stations.

Krauthamer, S.; Das, R.; Bulawka, A.

1985-01-01

380

On the influence of process variables on the thermal conditions and properties of high pressure die-cast magnesium alloys  

Microsoft Academic Search

The influence of pressure and velocity in high-pressure magnesium die casting on the thermal conditions and on the casting properties is studied. Specimens with the shape of a tensile test plate with a thickness of 12 mm and a length of 295 mm were cast using the alloys AM20HP, AM50HP, AS41, AE42, AZ91HP. Two gate velocities of the liquid metal

Nahed A. El-Mahallawy; Mohamed A Taha; Engenius Pokora; Friedrich Klein

1998-01-01

381

Features of the structure, microstructure, and magnetic properties of manganese-aluminum spinels obtained in various thermal treatment conditions  

NASA Astrophysics Data System (ADS)

The structural, microstructural, and magnetic properties of aluminum-manganese oxide in the ratio Mn: Al = 1: 1 in the well-crystallized and nanoheterogeneous states have been investigated. This oxide is obtained under various thermal treatment conditions and at different partial pressures of oxygen. The composition and cation distribution of the manganese and aluminum ions in spinel sites are determined. It is shown that the studied compound is a ferrimagnet with the Curie point T C ? 26 K.

Balaev, D. A.; Bulavchenko, O. A.; Dubrovskii, A. A.; Tsybulya, S. V.; Cherepanova, S. V.; Gerasimov, E. Yu.; Shaikhutdinov, K. A.

2013-07-01

382

Thermal simulation: Response factor analysis using three-dimensional CFD in the simulation of air conditioning control  

Microsoft Academic Search

The heat generated from an air-conditioning equipment or other thermal loads is distributed throughout a room by a three-dimensional\\u000a airflow. This three-dimensional airflow creates a three-dimensional heat distribution in a room. To better understand building\\u000a performance, we must integrate this spatial distribution into building simulations. Thus, three-dimensional computational\\u000a fluid dynamics (CFD) analysis is necessary in design process because most conventional

Kyosuke Hiyama; Shinsuke Kato; Yoshihiro Ishida

2010-01-01

383

Solar thermal technologies - Potential benefits to U.S. utilities and industry  

NASA Technical Reports Server (NTRS)

Solar energy systems were investigated which complement nuclear and coal technologies as a means of reducing the U.S. dependence on imported petroleum. Solar Thermal Energy Systems (STES) represents an important category of solar energy technologies. STES can be utilized in a broad range of applications servicing a variety of economic sectors, and they can be deployed in both near-term and long-term markets. The net present value of the energy cost savings attributable to electric utility and IPH applications of STES were estimated for a variety of future energy cost scenarios and levels of R&D success. This analysis indicated that the expected net benefits of developing an STES option are significantly greater than the expected costs of completing the required R&D. In addition, transportable fuels and chemical feedstocks represent a substantial future potential market for STES. Due to the basic nature of this R&D activity, however, it is currently impossible to estimate the value of STES in these markets. Despite this fact, private investment in STES R&D is not anticipated due to the high level of uncertainty characterizing the expected payoffs. Previously announced in STAR as N83-10547

Terasawa, K. L.; Gates, W. R.

1983-01-01

384

Apparatus for determining past-service conditions and remaining life of thermal barrier coatings and components having such coatings  

DOEpatents

An apparatus for determining past-service conditions and/or remaining useful life of a component of a combustion engine and/or a thermal barrier coating ("TBC") of the component comprises a radiation source that provides the exciting radiation to the TBC to excite a photoluminescent ("PL") material contained therein, a radiation detector for detecting radiation emitted by the PL material, and means for relating a characteristic of an emission spectrum of the PL material to the amount of a crystalline phase in the TBC, thereby inferring the past-service conditions or the remaining useful life of the component or the TBC.

Srivastava, Alok Mani (Niskayuna, NY); Setlur, Anant Achyut (Niskayuna, NY); Comanzo, Holly Ann (Niskayuna, NY); Devitt, John William (Clifton Park, NY); Ruud, James Anthony (Delmar, NY); Brewer, Luke Nathaniel (Rexford, NY)

2004-05-04

385

Micromachined thermally based CMOS microsensors  

Microsoft Academic Search

An integrated circuit (IC) approach to thermal microsensors is presented. The focus is on thermal sensors with on-chip bias and signal conditioning circuits made by industrial complementary metal-oxide-semiconductor (CMOS) IC technology in combination with post-CMOS micromachining or deposition techniques. CMOS materials and physical effects pertinent to thermal sensors are summarized together with basic structures used for microheaters, thermistors, thermocouples, thermal

HENRY BALTES; OLIVER PAUL; OLIVER BRAND

1998-01-01

386

Low-thrust chemical propulsion system propellant expulsion and thermal conditioning study. Executive summary  

NASA Technical Reports Server (NTRS)

Preferred techniques for providing abort pressurization and engine feed system net positive suction pressure (NPSP) for low thrust chemical propulsion systems (LTPS) were determined. A representative LTPS vehicle configuration is presented. Analysis tasks include: propellant heating analysis; pressurant requirements for abort propellant dump; and comparative analysis of pressurization techniques and thermal subcoolers.

Merino, F.; Wakabayashi, I.; Pleasant, R. L.; Hill, M.

1982-01-01

387

Relationship of ambient deposition conditions to formation of thermally activated voids in Al/Si interconnects  

SciTech Connect

The failure of microelectronics chips due to formation of stress-induced voids in Al/Si alloy interconnects is discussed. The propensity for thermal voiding in Al/Si is associated with a particular microstructural and compositional state derived from poor vacuum coditions during deposition.(AIP)

Tice, W.; Slusser, G. (IBM General Technology Division, Essex Junction, Vermont 05452 (US))

1990-01-01

388

Control properties of thermally coupled distillation sequences for different operating conditions  

Microsoft Academic Search

The understanding of the dynamic behavior of distillation columns has received considerable attention due to the fact that distillation is one of the most widely used unit operations in chemical process industries. Thermally coupled distillation sequences (TCDS) can provide significant energy savings with respect to the operation of sequences based on conventional distillation columns. TCDS exhibit a complex structure, with

Juan Gabriel Segovia-hernández; Esteban Abelardo Hernández-vargas; Jorge Alberto Márquez-muñoz

2007-01-01

389

Partial and whole-body thermal sensation and comfort— Part I: Uniform environmental conditions  

Microsoft Academic Search

Subjects exposed to uniform environments were polled for their local and overall (whole-body) thermal sensation and comfort. Sensation and comfort for local body parts vary greatly. In cool environments, hands and feet feel colder than other body parts. The head, insensitive to cold but sensitive to warm, feels warmer than the rest of the body in warm environments. Overall sensation

Edward Arens; Hui Zhang; Charlie Huizenga

2006-01-01

390

[Effect of thermal power stations on the sanitary and biological conditions of water reservoirs].  

PubMed

Discharge of thermal waters from power stations can result in the development of thermophilic microorganisms in the water reservoirs and increased water pollution. Increased water temperature changes relationships between lysozyme-active and antilysozyme-active bacteria. The quality of water gets worse. PMID:11013739

Solovykh, G N; Fabarisova, L G; Nefedova, E M; Karnaukhova, I V; Raimova, E K

1998-01-01

391

Boundary condition independent dynamic compact models of packages and heat sinks from thermal transient measurements  

Microsoft Academic Search

In this paper a methodology developed for the generation of transient compact models of packages and heat sinks from measured thermal transient results is described. The main advantage of generating dynamic compact models solely from measured results is the time-gain: the lengthy transient simulations, suggested by the DELPHI methodology can be omitted. After summarizing the procedure of generating the compact

M. Rencz; G. Farkas; V. Szekely; A. Poppe; B. Courtois

2003-01-01

392

Thermal convection of non-Newtonian fluids under low gravity conditions  

Microsoft Academic Search

Thermal buoyancy convection under the influence of weak mass forces is studied. Different models of nonlinear viscous and viscoplastic behavior and different orientations of the temperature gradient with respect to the vector of mass force acceleration are considered. Analytical methods of the theory, variational methods, and the numerical finite-difference method are used. The finite-amplitude character of the onset of convection

T. P. Lyubimova

1992-01-01

393

Characterization of Al2O3 Supported Nickel Catalysts Derived from RFNon-thermal Plasma Technology  

SciTech Connect

Catalysts derived from non-thermal plasma techniques have previously shown unusual and highly advantageous catalytic properties including room temperature reduction, unusual metal particle structure and metal-support interactions, and enhanced selectivity and stability. This study focuses on the characterization of Al2O3 supported Ni catalysts derived from the RF non-thermal plasma technique with in-situ XRD, TPR-MS and STEM and on relating the results to the enhanced activity and stability of benzene hydrogenation. The results suggest that catalysts with plasma treatments before impregnation are relatively easier to be reduced and result in better activities under mild reduction conditions. These plasma treatments stabilize the nickel particle sizes of air(B) and H2(B) catalysts at 600 C by slowing down the sintering process. Plasma treatments after the impregnation of precursors, on the other hand, tend to delay the growth of nickel particles below 600 C, forming smaller Ni particles, but with a sudden increase in particle size near 600 C. It suggests that the structure of Ni nitrate and the metal-support interaction have been altered by the plasma treatments. The reduction patterns of plasma 1 treated catalysts are, therefore, changed. The catalyst with a combination plasma treatment demonstrates that the effect of a combination plasma treatment is larger than either the plasma treatment before or after the impregnation alone. Both plasma treatments before and after the impregnation of metal precursor play important roles in modifying supported metal catalysts.

Jang, Ben W [ORNL; Helleson, Michael J [ORNL; Shi, Chunkai [ORNL; Rondinone, Adam Justin [ORNL; Schwartz, Viviane [ORNL; Liang, Chengdu [ORNL; Overbury, Steven {Steve} H [ORNL

2008-01-01

394

On process variation tolerant low cost thermal sensor design in 32nm CMOS technology  

Microsoft Academic Search

Thermal management has emerged as an important design issue in a range of designs from portable devices to server systems. Internal thermal sensors are an integral part of such a management system. Process variations in CMOS circuits cause accuracy problems for thermal sensors which can be fixed by calibration tables. Stand-alone thermal sensors are calibrated to fix such problems. However,

Spandana Remarsu; Sandip Kundu

2009-01-01

395

Thermal management of electronic equipment - A review of technology and research topics  

Microsoft Academic Search

The definition of thermal design criteria, and the establishment of a thermal packaging database, in electronic heat transfer research are discussed. The examples of DRAM chips, flat-leaded packages of logic chips, and modules with dismountable heat sinks are used to address thermal stress problems, the problems of fin design, and thermal interface management, respectively. Natural convection cooling is discussed, assessing

Wataru Nakayama

1986-01-01

396

Sensing technologies to measure metabolic activities in soil and assess its health conditions  

NASA Astrophysics Data System (ADS)

Soil is a complex ecosystem comprised of several and mutually interacting components, both abiotic (organo-mineral associations) and biotic (microbial and pedofaunal populations and plants), where a single parameter depends on other factors and affects the same and other factors, so that a network of influences among organisms coexists with the reciprocal actions between organisms and their environment. Therefore, it is difficult to undoubtedly determine what is the cause and what the effect within relationships between factors and processes. Soil is commonly studied through the evaluation and measurement of single parameters (e.g. the content of soil organic matter (SOM), microbial biomass, enzyme activities, pH, etc.), events (e.g. soil erosion, compaction, etc.) and processes (e.g. soil respiration, carbon fluxes, nitrification/denitrification, etc.), often carried out in laboratory conditions in order to limit the number of factors acting within the ecosystem under study, but missing the information about the global soil environment that way. In the last decade, several scientists have proposed and suggested the need for a holistic approach to soil ecosystems in different contexts. Recently, we have applied a sensing system developed in the last decades and capable of analysing complex mixtures of gases and volatiles (odours or aromas) in atmospheres, namely called electronic nose (EN). Typically, ENs are devices consisting of an array of differentially and partially specific, despite selective, sensors upon diverse coatings of sensitive films, i.e. interacting with single analytes of the same chemical class, despite not highly specific for a single substance, only, but showing also lower extent of cross-selectivity towards compounds of other chemical classes. ENs can be used in the classifications of odours by processing the collected responses of all sensors in the array through pattern recognition analyses, in order to obtain a chemical fingerprint (olfactory fingerprint) typical of the analysed air sample. Due to these features, we decided to apply such a sensing technology to the analyses of soil atmospheres, because several processes in soil, both abiotic and biotic, result in gas and/or volatile production and the dynamics of such releases may also be affected by several additional environmental factors, such as soil moisture, temperature, gas exchange rates with outer atmosphere, adsorption/desorption processes, etc. Then, the analysis of soil atmosphere may provide information about global soil conditions (e.g. soil quality and health), according to a holistic approach, where several factors are contemporarily taken into account. At the same time, the use of such a technology, if adequately trained on purpose, can supply information about a single or a pool of processes sharing similar features, which occur in soil over a certain period of time and mostly affecting soil atmosphere. According to these premises and hypotheses, we demonstrated that EN is an useful technology to measure soil microbial activity, through its correlation to specific metabolic activities occurring in soil (i.e. global and specific respiration and some enzyme activities), but also soil microbial biomass. On the basis of such evidences, we also were able to use this technology to assess the quality and health conditions of soil ecosystems in terms of metabolic indices previously identified, according to some metabolic parameters and biomass quantification of microbial populations. In other studies, we also applied EN technology, despite using a different set of sensors in the array, to analyse the atmosphere of soil ecosystems in order to assess their environmental conditions after contamination with polycyclic aromatic hydrocarbons (PAHs) (i.e. semivolatile - SVOCs - organic pollutants). In this case, EN technology resulted capable of distinguishing between contaminated and uncontaminated soils, according to the differences in a list of substances, occurring in the atmospheres of differently treated soils, which were identified throu

De Cesare, Fabrizio; Macagnano, Antonella

2013-04-01

397

Advanced Technology Thermal Energy Storage and Heat Exchange Systems for Solar Applications: A Survey of Current Research.  

National Technical Information Service (NTIS)

A survey is presented of the advanced research and development projects underway in the U.S. in all of the known media and methods for storing and transferring thermal energy in solar applications. The technologies reviewed include innovative heat exchang...

A. I. Michaels

1978-01-01

398

Removal of volatile organic compounds from air streams and industrial flue gases by non-thermal plasma technology  

Microsoft Academic Search

Gaseous pollution control technologies for acid gases (NOx , SOx, etc.), volatile organic compounds (VOC), greenhouse gases, ozone layer depleting substance (ODS), etc., have been commercialized based on catalysis, incineration and adsorption methods. However, non-thermal plasma techniques based on electron beams and corona discharges become significant due to advantages such as lower cost, higher removal efficiency, smaller space volume, etc.

Kuniko Urashima; Jen-Shih Chang

2000-01-01

399

Advanced technology thermal energy storage and heat exchange systems for solar applications: a survey of current research  

Microsoft Academic Search

A survey is presented of the advanced research and development projects underway in the U.S. in all of the known media and methods for storing and transferring thermal energy in solar applications. The technologies reviewed include innovative heat exchange and heat transport methods, advanced sensible heat storage in water, rocks, earth and combinations of these for both short term and

Michaels

1978-01-01

400

Building Thermal Envelope Systems and Materials (BTESM) and research utilization\\/technology transfer: Monthly progress report, March 1988  

Microsoft Academic Search

The Monthly Report of the Building Thermal Envelope Systems and Materials (BTESM) Program is a monthly update of both in-house ORNL projects and subcontract activities in the research areas of building materials, wall systems, foundations, roofs, building diagnostics, and research utilization and technology transfer.

S. D. Samples; G. L. Coleman

1988-01-01

401

Thermal monitoring of transport infrastructures by infrared thermography coupled with inline local atmospheric conditions survey  

NASA Astrophysics Data System (ADS)

An infrared system architecture (software and hardware) has been studied and developed to allow long term monitoring of transport infrastructures in a standalone configuration. It is based on the implementation of low cost infrared thermal cameras (equipped with uncooled microbolometer focal plane array) available on the market coupled with other measurement systems. All data collected feed simplified radiative models running on GPU available on small PC to produce corrected thermal map of the surveyed structure at selected time step. Furthermore, added Web-enabled capabilities of this new infrared measurement system are also presented and discussed. A prototype of this system was tested and evaluated on real infrastructure opened to traffic. Results obtained by image and signal processing are presented. Finally, conclusions and perspectives for new implementation and new functionalities are presented and discussed.

Dumoulin, J.

2013-09-01

402

Effects of load and thermal conditions on Pb-free solder joint reliability  

Microsoft Academic Search

Reliability of lead-free solder joints has been a hot topic widely debated in the electronic industry. Most published data\\u000a indicate that a change to lead-free soldering has the potential benefit of more reliable solder joints than the current Sn-Pb\\u000a eutectic solder joints. However, in reality many mechanical, metallurgical, thermal, and environmental factors affect the\\u000a service reliability of solder joints. This

J. Liang; S. Downes; N. Dariavach; D. Shangguan; S. M. Heinrich

2004-01-01

403

Normal Condition on Transport Thermal Analysis and Testing of a Type B Drum Package  

SciTech Connect

Increasing the content limits of radioactive material packagings can save money and increase transportation safety by decreasing the total number of shipments required to transport large quantities of material. The contents of drum packages can be limited by unacceptable containment vessel pressures and temperatures due to the thermal properties of the insulation. The purpose of this work is to understand and predict the effects of insulation properties on containment system performance.

Jerrell, J.W.; van Alstine, M.N.; Gromada, R.J.

1995-03-21

404

Influence of thermal boundary conditions on heat transfer from a cylinder in cross flow  

Microsoft Academic Search

Local heat transfer data over the leading surface of a cylinder in crossflow were obtained for a Reynolds number range of 50,000. The cylinder was operated at both uniform-wall-temperature and uniform-heat-flux thermal ance of 80 deg from the front stagnation point, the uniform-wall-temperature heat transfer coefficients were as much as 66 percent lower than the uniform-heat-flux data. Between the stagnation

S. S. Papell

1981-01-01

405

Thermal conditions in a hot evaporating cathode in a stationary vacuum arc with diffuse cathode emission  

Microsoft Academic Search

A study has been made of an arc on a thermally insulated metal cathode with indirect electron-beam heating. The cathode material (gadolinium) resembles ordinary refractory metals in having a small ratio of the evaporated-atom flux to the thermionic-emission electron one. At cathode temperatures T \\/SUB c\\/ greater than or equal to 1900°K and saturation-vapor pressures greater than or equal to

S. N. Paranin; V. P. Polishchuk; V. I. Shabashov; P. E. Sychev; I. M. Yartsev

1986-01-01

406

Influence of electrical current variance and thermal resistances on optimum working conditions and geometry for thermoelectric energy harvesting  

NASA Astrophysics Data System (ADS)

Recent reports on enhanced thermoelectric figure of merits based on nanoscale effects have revived interest in potential applications of thermoelectric modules for waste heat recovery and distributed power generation. However, studies of optimized working conditions have not been thoroughly investigated. The majority of the previous studies on optimum load resistance for maximum power output or maximum efficiency assume temperatures at the ends of thermoelectric materials are known and constant. In reality, temperature should be determined by the energy conservation equations, which are functions of the load resistance, as well as the thermal resistances of the heat source, heat sink, and contact pads. This work exploits a numerical method to determine the actual temperature of thermoelectric materials, and optimum working conditions for thermoelectric energy harvesting are presented. The proposed model considers the effect of thermal resistances between a thermoelectric module and heat reservoirs, and the electrical current variation with respect to load resistance. The optimum condition for load resistance ratio was observed to occur at larger values than those obtained from traditional optimization work. Additionally, optimum geometry for a thermoelectric module is suggested for energy harvesting methods, where forced convection or oversized heat sinks cannot be used. Experimental results obtained from a commercial thermoelectric module are also presented to validate the proposed model. This work forms a basis to predict optimum working conditions in various thermoelectric energy harvesting applications.

Gomez, Miguel; Reid, Rachel; Ohara, Brandon; Lee, Hohyun

2013-05-01

407

Waking the sleeping giant: Introducing new heat exchanger technology into the residential air-conditioning marketplace  

SciTech Connect

The Air Conditioning Industry has made tremendous strides in improvements to the energy efficiency and reliability of its product offerings over the past 40 years. These improvement can be attributed to enhancements of components, optimization of the energy cycle, and modernized and refined manufacturing techniques. During this same period, energy consumption for space cooling has grown significantly. In January of 1992, the minimum efficiency requirement for central air conditioning equipment was raised to 10 SEER. This efficiency level is likely to increase further under the auspices of the National Appliance Energy Conservation Act (NAECA). A new type of heat exchanger was developed for air conditioning equipment by Modine Manufacturing Company in the early 1990's. Despite significant advantages in terms of energy efficiency, dehumidification, durability, and refrigerant charge there has been little interest expressed by the air conditioning industry. A cooperative effort between Modine, various utilities, and several state energy offices has been organized to test and demonstrate the viability of this heat exchanger design throughout the nation. This paper will review the fundamentals of heat exchanger design and document this simple, yet novel technology. These experiences involving equipment retrofits have been documented with respect to the performance potential of air conditioning system constructed with PF{trademark} Heat Exchangers (generically referred to as microchannel heat exchangers) from both an energy efficiency as well as a comfort perspective. The paper will also detail the current plan to introduce 16 to 24 systems into an extended field test throughout the US which commenced in the Fall of 1997.

Chapp, T.; Voss, M.; Stephens, C.

1998-07-01

408

Advanced technologies for scalable ATLAS conditions database access on the grid  

NASA Astrophysics Data System (ADS)

During massive data reprocessing operations an ATLAS Conditions Database application must support concurrent access from numerous ATLAS data processing jobs running on the Grid. By simulating realistic work-flow, ATLAS database scalability tests provided feedback for Conditions Db software optimization and allowed precise determination of required distributed database resources. In distributed data processing one must take into account the chaotic nature of Grid computing characterized by peak loads, which can be much higher than average access rates. To validate database performance at peak loads, we tested database scalability at very high concurrent jobs rates. This has been achieved through coordinated database stress tests performed in series of ATLAS reprocessing exercises at the Tier-1 sites. The goal of database stress tests is to detect scalability limits of the hardware deployed at the Tier-1 sites, so that the server overload conditions can be safely avoided in a production environment. Our analysis of server performance under stress tests indicates that Conditions Db data access is limited by the disk I/O throughput. An unacceptable side-effect of the disk I/O saturation is a degradation of the WLCG 3D Services that update Conditions Db data at all ten ATLAS Tier-1 sites using the technology of Oracle Streams. To avoid such bottlenecks we prototyped and tested a novel approach for database peak load avoidance in Grid computing. Our approach is based upon the proven idea of pilot job submission on the Grid: instead of the actual query, an ATLAS utility library sends to the database server a pilot query first.

Basset, R.; Canali, L.; Dimitrov, G.; Girone, M.; Hawkings, R.; Nevski, P.; Valassi, A.; Vaniachine, A.; Viegas, F.; Walker, R.; Wong, A.

2010-04-01

409

A study of the thermal decomposition of adulterated cocaine samples under optimized aerobic pyrolytic conditions  

Microsoft Academic Search

The pyrolysis behaviour of pure cocaine base as well as the influence of various additives was studied using conditions that are relevant to the smoking of illicit cocaine by humans. For this purpose an aerobic pyrolysis device was developed and the experimental conditions were optimized. In the first part of our study the optimization of some basic experimental parameters of

T. Gosti?; S. Klemenc; B. Štefane

2009-01-01

410

Status of not-in-kind refrigeration technologies for household space conditioning, water heating and food refrigeration  

SciTech Connect

This paper presents a review of the next generation not-in-kind technologies to replace conventional vapor compression refrigeration technology for household applications. Such technologies are sought to provide energy savings or other environmental benefits for space conditioning, water heating and refrigeration for domestic use. These alternative technologies include: thermoacoustic refrigeration, thermoelectric refrigeration, thermotunneling, magnetic refrigeration, Stirling cycle refrigeration, pulse tube refrigeration, Malone cycle refrigeration, absorption refrigeration, adsorption refrigeration, and compressor driven metal hydride heat pumps. Furthermore, heat pump water heating and integrated heat pump systems are also discussed due to their significant energy saving potential for water heating and space conditioning in households. The paper provides a snapshot of the future R&D needs for each of the technologies along with the associated barriers. Both thermoelectric and magnetic technologies look relatively attractive due to recent developments in the materials and prototypes being manufactured.

Bansal, Pradeep [ORNL; Vineyard, Edward Allan [ORNL; Abdelaziz, Omar [ORNL

2012-01-01

411

Cultural repertoires and food-related household technology within colonia households under conditions of material hardship  

PubMed Central

Introduction Mexican-origin women in the U.S. living in colonias (new-destination Mexican-immigrant communities) along the Texas-Mexico border suffer from a high incidence of food insecurity and diet-related chronic disease. Understanding environmental factors that influence food-related behaviors among this population will be important to improving the well-being of colonia households. This article focuses on cultural repertoires that enable food choice and the everyday uses of technology in food-related practice by Mexican-immigrant women in colonia households under conditions of material hardship. Findings are presented within a conceptual framework informed by concepts drawn from sociological accounts of technology, food choice, culture, and material hardship. Methods Field notes were provided by teams of promotora-researchers (indigenous community health workers) and public-health professionals trained as participant observers. They conducted observations on three separate occasions (two half-days during the week and one weekend day) within eight family residences located in colonias near the towns of Alton and San Carlos, Texas. English observations were coded inductively and early observations stressed the importance of technology and material hardship in food-related behavior. These observations were further explored and coded using the qualitative data package Atlas.ti. Results Technology included kitchen implements used in standard and adapted configurations and household infrastructure. Residents employed tools across a range of food-related activities identified as forms of food acquisition, storage, preparation, serving, feeding and eating, cleaning, and waste processing. Material hardships included the quality, quantity, acceptability, and uncertainty dimensions of food insecurity, and insufficient consumption of housing, clothing and medical care. Cultural repertoires for coping with material hardship included reliance on inexpensive staple foods and dishes, and conventional and innovative technological practices. These repertoires expressed the creative agency of women colonia residents. Food-related practices were constrained by climate, animal and insect pests, women’s gender roles, limitations in neighborhood and household infrastructure, and economic and material resources. Conclusions This research points to the importance of socioeconomic and structural factors such as gender roles, economic poverty and material hardship as constraints on food choice and food-related behavior. In turn, it emphasizes the innovative practices employed by women residents of colonias to prepare meals under these constraints. PMID:22587790

2012-01-01

412

Kinetics of thermal de-chlorination of PVC under pyrolytic conditions  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer Several tests were performed in DTA/TGA for understanding the thermal behavior of pure PVC. Black-Right-Pointing-Pointer We did a kinetic model for the de-chlorination of PVC molecule. Black-Right-Pointing-Pointer A temperature of 340 Degree-Sign C was defined as the optimum temperature for breaking the bond of chlorine in the PVC molecule. Black-Right-Pointing-Pointer The experimental validation of this temperature, led to a removal rate of 99.9% chlorine. - Abstract: Although PVC-containing wastes are an important potential source of energy they are frequently disposed in landfill. In thermal treatment processes such as pyrolysis and gasification, the presence of poly(vinyl chloride) (PVC), a compound with 56.7% of chlorine, may cause problems concerned with environmental protection, as consequence of the formation of hydrochloric acid, chlorine gas and dioxins, as well as corrosion phenomena of the reactor/equipment materials. Thus, a possible solution may involve a previous removal of the chlorine from PVC containing waste through a pyrolysis process at low temperatures before the material being submitted to a subsequent thermal treatment, for energetic valorization. In this work, a kinetic model for the thermal decomposition of PVC has been developed, in view of its de-chlorination. DTA/TGA testing at different temperatures indicated a first order reaction and an activation energy of 133,800 J/mol. An almost completed de-chlorination reaction was obtained at 340 Degree-Sign C under an inert atmosphere. The resulted material is a C{sub n}H{sub n} type polymer with potential to be used in an energy recovery process. Validation test performed at laboratory scale indicate that the temperature of 340 Degree-Sign C enables the removal of {approx}99.9% of the chlorine present in PVC. The chloride can be fixed in the form of an aqueous solution of HCl or calcium chloride, driving to an alternative full process with environmental benefits and reduction of the costs associated to the PCV - containing materials/wastes management.

Castro, Alexandra, E-mail: acastro@cvresiduos.pt [CVR - Centro para a Valorizacao de Residuos (Center for Waste Valorization), Guimaraes (Portugal); CT2M - Centre for Mechanical and Materials Technologies, Mechanical Engineering Department of Minho University, Guimaraes (Portugal); Soares, Delfim; Vilarinho, Candida; Castro, Fernando [CT2M - Centre for Mechanical and Materials Technologies, Mechanical Engineering Department of Minho University, Guimaraes (Portugal)

2012-05-15

413

ASi Photovoltaic\\/Thermal Solar Air-Conditioning System in Thailand  

Microsoft Academic Search

This work is concerned about using PVT solar system with air-conditioning system. This system is the first development of PVT air conditioning system in Thailand. The electricity produced from a-Si PV array is connected into grid by using DC\\/AC inverter. Hot water from the system is supplied to 20 RT adsorption chiller machine for producing cold water. Present estimated electricity

J. Phongsitong; S. Jaikla; T. Nualboonrueng; P. Sichanutgrist

2006-01-01

414

Fuel Used for Vehicle Air Conditioning: A State-by-State Thermal Comfort-Based Approach  

Microsoft Academic Search

How much fuel does vehicle air conditioning actually use? This study attempts to answer that question to determine the national and state-by-state fuel use impact seen by using air conditioning in light duty gasoline vehicles. The study used data from US cities, representative of averages over the past 30 years, 1X—see Definitions, the Toyota Prius, the Honda Insight, a 3X

Valerie H. Johnson

415

Clutter sensitivity test under controlled field conditions Resonant Microstrip Patch Antenna (RMPA) sensor technology  

SciTech Connect

Theoretical research, controlled laboratory tests, and these field test results show that nonmetallic (and metallic) shallowly buried objects can be detected and imaged with the Resonant Microstrip Patch Antenna (RMPA) sensor. The sensor can be modeled as a high Q cavity which capitalizes on its resonant condition sensitivity to scattered waves from buried objects. When the RMPA sensor is swept over a shallowly buried object, the RMPA fed-point impedance (resistance), measured with a Maxwell bridge, changes by tens of percent. The significant change in unprocessed impedance data can be presented in two-dimensional and three-dimensional graphical displays over the survey area. This forms silhouette images of the objects without the application of computationally intensive data processing algorithms. Because RMPA employed electromagnetic waves to illuminate the shallowly buried object, a number of questions and issues arise in the decision to fund or deny funding of the reconfiguration of the RMPA technology into a nonmetallic (metallic) land mine detector.

NONE

1996-06-27

416

Japanese power electronics inverter technology and its impact on the American air conditioning industry  

SciTech Connect

Since 1983, technological advances and market growth of inverter- driven variable-speed heat pumps in Japan have been dramatic. The high level of market penetration was promoted by a combination of political, economic, and trade policies in Japan. A unique environment was created in which the leading domestic industries-- microprocessor manufacturing, compressors for air conditioning and refrigerators, and power electronic devices--were able to direct the development and market success of inverter-driven heat pumps. As a result, leading US variable-speed heat pump manufacturers should expect a challenge from the Japanese producers of power devices and microprocessors. Because of the vertically-integrated production structure in Japan, in contrast to the out-sourcing culture of the United States, price competition at the component level (such as inverters, sensors, and controls) may impact the structure of the industry more severely than final product sales. 54 refs., 47 figs., 1 tab.

Ushimaru, Kenji.

1990-08-01

417

Introduction Analysis of Refrigerating and Air-Conditioning Technologies in Micro Grid Type Food Industrial Park  

NASA Astrophysics Data System (ADS)

The aim of this study was to evaluate the refrigerating and air-conditioning technologies in cases of introducing both cogeneration system and energy network in food industrial park. The energy data of 14 factories were classified into steam, hot water, heating, cooling, refrigerating, freezing and electric power by interviews. The author developed a micro grid model based on linear programming so as to minimize the total system costs. The industrial park was divided into the 2,500 square meter mesh in order to take steam transport into consideration. Four cases were investigated. It was found that the electric power driven freezer was introduced compared with the ammonia absorption freezer. The ammonia absorption freezer was introduced in the factory that there is a little steam demand and large freezing demand at the same time.

Shimazaki, Yoichi

418

Technology development plan: Geotechnical survey systems for OTEC (Ocean Thermal Energy Conversion) cold water pipes  

NASA Astrophysics Data System (ADS)

An overview is given of current and developing technologies and techniques for performing geotechnical investigations for siting and designing Cold Water Pipes (CWP) for shelf-resting Ocean Thermal Energy Conversion (OTEC) power plants. The geotechnical in situ tools used to measure the required parameters and the equipment/systems used to deploy these tools are identified. The capabilities of these geotechnical tools and deployment systems are compared to the data requirements for the CWP foundation/anchor design, and shortfalls are identified. For the last phase of geotechnical data gathering for design, a drillship will be required to perform soil boring work, to obtain required high quality sediment samples for laboratory dynamic testing, and to perform deep penetration in situ tests. To remedy shortfalls and to reduce the future OTEC CWP geotechnical survey costs, it is recommended that a seafloor resting machine be developed to advance the friction cone penetrometer, and also probably a pressuremeter, to provide geotechnical parameters to shallow subseafloor penetrations on slopes of 35 deg and in water depths to 1300 m.

Valent, Philip J.; Riggins, Michael

1989-04-01

419

Solar-thermal technology development: estimated market size and energy cost savings. Volume I. Executive summary  

SciTech Connect

Estimated future energy cost savings associated with the development of cost-competitive solar thermal technologies (STT) are discussed. Analysis is restricted to STT in electric applications for 16 high-insolation/high-energy-price states. Three fuel price scenarios and three 1990 STT system costs are considered, reflecting uncertainty over future fuel prices and STT cost projections. STT R and D is found to be unacceptably risky for private industry in the absence of federal support. Energy cost savings were projected to range from $0 to $10 billion (1990 values in 1981 dollars), depending on the system cost and fuel price scenario. Normal R and D investment risks are accentuated because the Organization of Petroleum Exporting Countries (OPEC) cartel can artifically manipulate oil prices and undercut growth of alternative energy sources. Federal participation in STT R and D to help capture the potential benefits of developing cost-competitive STT was found to be in the national interest. Analysis is also provided regarding two federal incentives currently in use: the Federal Business Energy Tax Credit and direct R and D funding. These mecahnisms can be expected to provide the required incentives to establish a viable self-sustaining private STT industry. Discussions of STT impacts on the environment and oil imports are also included.

Gates, W.R.

1983-02-01

420

Solar-thermal technologies benefits assessment: objectives, methodologies, and results for 1981  

SciTech Connect

The future economic and social benefits of developing cost-competitive solar thermal technologies (STT) were assessed during FY 81. The analysis was restricted to STT in electric applications for 16 high-insolation/high-energy-price states. Three fuel price scenarios and three 1990 STT system costs were considered, reflecting uncertainty over future fuel prices and STT cost projections. After considering the numerous benefits of introducing STT into the energy market, three primary benefits were identified and evaluated: (1) direct energy cost savings were estimated to range from zero to $50 billion; (2) oil imports may be reduced by up to 9 percent, improving national security; (3) significant environmental benefits can be realized in air basins where electric power plant emissions create substantial air pollution problems. STT R and D was found to be unacceptably risky for private industry in the absence of federal support. The normal risks associated with investments in R and D are accentuated because the OPEC cartel can artificially manipulate oil prices and undercut the growth of alternative energy sources. When this fact was weighed against the potential benefits of developing cost-competitive STT, Federal participation in STT R and D was found to be in the national interest.

Gates, W.R.

1982-07-01

421

Metallic Thermal Protection System Technology Development: Concepts, Requirements and Assessment Overview  

NASA Technical Reports Server (NTRS)

A technology development program was conducted to evolve an earlier metallic thermal protection system (TPS) panel design, with the goals of: improving operations features, increasing adaptability (ease of attaching to a variety of tank shapes and structural concepts), and reducing weight. The resulting Adaptable Robust Metallic Operable Reusable (ARMOR) TPS system incorporates a high degree of design flexibility (allowing weight and operability to be traded and balanced) and can also be easily integrated with a large variety of tank shapes, airframe structural arrangements and airframe structure/material concepts. An initial attempt has been made to establish a set of performance based TPS design requirements. A set of general (FARtype) requirements have been proposed, focusing on defining categories that must be included for a comprehensive design. Load cases required for TPS design must reflect the full flight envelope, including a comprehensive set of limit loads, However, including additional loads. such as ascent abort trajectories, as ultimate load cases, and on-orbit debris/micro-meteoroid hypervelocity impact, as one of the discrete -source -damage load cases, will have a significant impact on system design and resulting performance, reliability and operability. Although these load cases have not been established, they are of paramount importance for reusable vehicles, and until properly included, all sizing results and assessments of reliability and operability must be considered optimistic at a minimum.

Dorsey, John T.; Poteet, Carl C.; Chen, Roger R.; Wurster, Kathryn E.

2002-01-01

422

Solar thermal technologies benefits assessment: Objectives, methodologies and results for 1981  

NASA Astrophysics Data System (ADS)

The economic and social benefits of developing cost competitive solar thermal technologies (STT) were assessed. The analysis was restricted to STT in electric applications for 16 high insolation/high energy price states. Three fuel price scenarios and three 1990 STT system costs were considered, reflecting uncertainty over fuel prices and STT cost projections. After considering the numerous benefits of introducing STT into the energy market, three primary benefits were identified and evaluated: (1) direct energy cost savings were estimated to range from zero to $50 billion; (2) oil imports may be reduced by up to 9 percent, improving national security; and (3) significant environmental benefits can be realized in air basins where electric power plant emissions create substantial air pollution problems. STT research and development was found to be unacceptably risky for private industry in the absence of federal support. The normal risks associated with investments in research and development are accentuated because the OPEC cartel can artificially manipulate oil prices and undercut the growth of alternative energy sources.

Gates, W. R.

1982-07-01

423

Solar thermal technologies benefits assessment: Objectives, methodologies and results for 1981  

NASA Technical Reports Server (NTRS)

The economic and social benefits of developing cost competitive solar thermal technologies (STT) were assessed. The analysis was restricted to STT in electric applications for 16 high insolation/high energy price states. Three fuel price scenarios and three 1990 STT system costs were considered, reflecting uncertainty over fuel prices and STT cost projections. After considering the numerous benefits of introducing STT into the energy market, three primary benefits were identified and evaluated: (1) direct energy cost savings were estimated to range from zero to $50 billion; (2) oil imports may be reduced by up to 9 percent, improving national security; and (3) significant environmental benefits can be realized in air basins where electric power plant emissions create substantial air pollution problems. STT research and development was found to be unacceptably risky for private industry in the absence of federal support. The normal risks associated with investments in research and development are accentuated because the OPEC cartel can artificially manipulate oil prices and undercut the growth of alternative energy sources.

Gates, W. R.

1982-01-01

424

Thermal performance simulation of a solar cavity receiver under windy conditions  

SciTech Connect

Solar cavity receiver plays a dominant role in the light-heat conversion. Its performance can directly affect the efficiency of the whole power generation system. A combined calculation method for evaluating the thermal performance of the solar cavity receiver is raised in this paper. This method couples the Monte-Carlo method, the correlations of the flow boiling heat transfer, and the calculation of air flow field. And this method can ultimately figure out the surface heat flux inside the cavity, the wall temperature of the boiling tubes, and the heat loss of the solar receiver with an iterative solution. With this method, the thermal performance of a solar cavity receiver, a saturated steam receiver, is simulated under different wind environments. The highest wall temperature of the boiling tubes is about 150 C higher than the water saturation temperature. And it appears in the upper middle parts of the absorbing panels. Changing the wind angle or velocity can obviously affect the air velocity inside the receiver. The air velocity reaches the maximum value when the wind comes from the side of the receiver (flow angle {alpha} = 90 ). The heat loss of the solar cavity receiver also reaches a maximum for the side-on wind. (author)

Fang, J.B.; Wei, J.J.; Dong, X.W.; Wang, Y.S. [State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an 710049 (China)

2011-01-15

425

Annealing condition influences thermal hysteresis of fungal type ice-binding proteins.  

PubMed

The Antarctic sea ice diatom Navicular glaciei produced ice-binding protein (NagIBP) that is similar to the antifreeze protein (TisAFP) from snow mold Typhula ishikariensis. In the thermal hysteresis range of NagIBP, ice growth was completely inhibited. At the freezing point, the ice grew in a burst to 6 direction perdicular to the c-axis of ice crystal. This burst pattern is similar to TisAFP and other hyperactive AFPs. The thermal hysteresis of NagIBP and TisAFP could be increased by decreasing a cooling rate to allow more time for the proteins to bind ice. This suggests the possible second binding of proteins occurs on the ice surface, which might increase the hysteresises to a sufficient level to prevent freezing of the brine pockets which habitat of N. glaciei. The secondary ice binding was described as that after AFP molecules bind onto the flat ice plane irreversibly, which was based on adsorption-inhibition mechanism model at the ice-water interface, convex ice front was formed and overgrew during normal TH measurement (no annealing) until uncontrolled growth at the nonequilibrium freezing point. The results suggested that NagIBP is a hyperactive AFP that is expressed for freezing avoidance. PMID:24201106

Xiao, Nan; Hanada, Yuichi; Seki, Haruhiko; Kondo, Hidemasa; Tsuda, Sakae; Hoshino, Tamotsu

2014-02-01

426

Resource allocation between reproductive phases: the importance of thermal conditions in determining the cost of incubation.  

PubMed Central

Changes in the resources allocated to particular stages of reproduction are expected to influence allocation to, and performance in, subsequent reproductive stages. Experimental manipulation of individual investment patterns provides important evidence that such physiological trade-offs occur, and can highlight the key environmental variables that influence reproductive costs. By temporarily altering the thermal properties of starling nests, we reduced the energetic demand of first-clutch incubation, and examined the effect of this manipulation on performance during the same and the subsequent reproductive attempts. Compared with controls, starlings investing less in incubation were more successful in fledging young, and were more likely to hatch all their eggs if a subsequent reproductive attempt was made. Our results show that incubation demands can limit reproductive success, and that resources saved during incubation can be reallocated to later stages of the same reproductive attempt and to future reproductive attempts. This study also shows that small changes in thermal environment can affect breeding success by altering the energetic demands imposed on incubating parents, independently of the effect of temperature on other environmental variables such as food supply. PMID:10670950

Reid, J M; Monaghan, P; Ruxton, G D

2000-01-01

427

Thermophysical properties of nitrogen plasmas under thermal equilibrium and non-equilibrium conditions  

SciTech Connect

Calculated thermophysical properties of nitrogen plasmas in and out of thermal equilibrium are presented. The cut-off of the partition functions due to the lowering of the ionization potential has been taken into account, together with the contributions from different core excited electronic states. The species composition and thermodynamic properties are determined numerically using the Newton-Raphson iterative method, taking into account the corrections due to Coulomb interactions. The transport properties including diffusion coefficient, viscosity, thermal conductivity, and electrical conductivity are calculated using the most recent collision interaction potentials by adopting Devoto's electron and heavy particle decoupling approach, expanded to the third-order approximation (second-order for viscosity) in the framework of Chapman-Enskog method. Results are presented in the pressure range of 0.1 atm-10 atm and in electron temperature range from 300 to 40 000 K, with the ratio of electron temperature to heavy-particle temperature varied from 1 to 20. Results are compared with those from previous works, and the influences of different definitions of the Debye length are discussed.

Wang Weizong [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an Shaanxi 710049 (China); Department of Electrical Engineering and Electronics, University of Liverpool, Brownlow Hill, Liverpool L69 3GJ (United Kingdom); Rong Mingzhe [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an Shaanxi 710049 (China); Yan, J. D.; Spencer, Joseph W. [Department of Electrical Engineering and Electronics, University of Liverpool, Brownlow Hill, Liverpool L69 3GJ (United Kingdom); Murphy, A. B. [CSIRO Materials Science and Engineering, P.O. Box 218, Lindfield NSW 2070 (Australia)

2011-11-15

428

Nuclear Thermal Propulsion (NTP): A Proven Growth Technology for Human NEO/Mars Exploration Missions  

NASA Technical Reports Server (NTRS)

The nuclear thermal rocket (NTR) represents the next "evolutionary step" in high performance rocket propulsion. Unlike conventional chemical rockets that produce their energy through combustion, the NTR derives its energy from fission of Uranium-235 atoms contained within fuel elements that comprise the engine s reactor core. Using an "expander" cycle for turbopump drive power, hydrogen propellant is raised to a high pressure and pumped through coolant channels in the fuel elements where it is superheated then expanded out a supersonic nozzle to generate high thrust. By using hydrogen for both the reactor coolant and propellant, the NTR can achieve specific impulse (Isp) values of 900 seconds (s) or more - twice that of today s best chemical rockets. From 1955 - 1972, twenty rocket reactors were designed, built and ground tested in the Rover and NERVA (Nuclear Engine for Rocket Vehicle Applications) programs. These programs demonstrated: (1) high temperature carbide-based nuclear fuels; (2) a wide range of thrust levels; (3) sustained engine operation; (4) accumulated lifetime at full power; and (5) restart capability - all the requirements needed for a human Mars mission. Ceramic metal "cermet" fuel was pursued as well, as a backup option. The NTR also has significant "evolution and growth" capability. Configured as a "bimodal" system, it can generate its own electrical power to support spacecraft operational needs. Adding an oxygen "afterburner" nozzle introduces a variable thrust and Isp capability and allows bipropellant operation. In NASA s recent Mars Design Reference Architecture (DRA) 5.0 study, the NTR was selected as the preferred propulsion option because of its proven technology, higher performance, lower launch mass, versatile vehicle design, simple assembly, and growth potential. In contrast to other advanced propulsion options, no large technology scale-ups are required for NTP either. In fact, the smallest engine tested during the Rover program - the 25,000 lbf (25 klbf) "Pewee" engine is sufficient when used in a clustered engine arrangement. The "Copernicus" crewed spacecraft design developed in DRA 5.0 has significant capability and a human exploration strategy is outlined here that uses Copernicus and its key components for precursor near Earth object (NEO) and Mars orbital missions prior to a Mars landing mission. The paper also discusses NASA s current activities and future plans for NTP development that include system-level Technology Demonstrations - specifically ground testing a small, scalable NTR by 2020, with a flight test shortly thereafter.

Borowski, Stanley K.; McCurdy, David R.; Packard, Thomas W.

2012-01-01

429

Boundary Conditions and Correlations in Path Integrals for Quantum Field Theory of Thermal and Non-Equilibrium States  

E-print Network

For thermal equilibrium systems it is shown, how the Kubo-Martin-Schwinger boundary condition may be used to factorize the generating functional of Green functions at least on the level of the full two-point function. Genuine non-equilibrium system exhibit correlations that one may also incorporate in the path integral. One one hand this provides a natural tool for a perturbative expansion including these correlations. On the other hand it allows to prove that in general non-equilibrium systems the generating functional does not factorize.

P. A. Henning; R. Fauser

1996-05-22

430

Gene pleiotropy constrains gene expression changes in fish adapted to different thermal conditions  

PubMed Central

Understanding the factors that shape the evolution of gene expression is a central goal in biology, but the molecular mechanisms behind this remain controversial. A related major goal is ascertaining how such factors may affect the adaptive potential of a species or population. Here we demonstrate that temperature-driven gene expression changes in fish adapted to differing thermal environments are constrained by the level of gene pleiotropy estimated by either the number of protein interactions or gene biological processes. Genes with low pleiotropy levels were the main drivers of both plastic and evolutionary global expression profile changes, while highly pleiotropic genes had limited expression response to temperature treatment. Our study provides critical insights into the molecular mechanisms by which natural populations can adapt to changing environments. In addition to having important implications for climate change adaptation, these results suggest that gene pleiotropy should be considered more carefully when interpreting expression profiling data. PMID:24892934

Papakostas, Spiros; V?llestad, L. Asbj?rn; Bruneaux, Matthieu; Aykanat, Tutku; Vanoverbeke, Joost; Ning, Mei; Primmer, Craig R.; Leder, Erica H.

2014-01-01

431