Science.gov

Sample records for regional heat sources

  1. Heat sources for tertiary metamorphism and anatexis in the Annapurna-Manaslu region, central Nepal

    NASA Technical Reports Server (NTRS)

    England, Philip; Le Fort, Patrick; Molnar, Peter; Pecher, Arnaud

    1992-01-01

    The metamorphic evolution of the rocks near the Main Central Thrust in the Annapurna-Manaslu region of central Nepal is examined. In this region, all three types of metamorphic features can be observed: regional metamorphism, anatectic granitoids, and inverted metamorphic isograds. In this work, each phase of metamorphism is treated separately to estimate the heat sources required for each process. This approach makes it possible to identify the important parameters for each process, to draw preliminary conclusions about the heat sources required for each of these phases, and to determine which parameters need to be measured more precisely in order to constrain these heat sources.

  2. UNVEILING THE MAIN HEATING SOURCES IN THE CEPHEUS A HW2 REGION

    SciTech Connect

    Jimenez-Serra, I.; Caselli, P.; MartIn-Pintado, J.; Rodriguez-Franco, A.; Martin, S.; Chandler, C.; Winters, J. M. E-mail: P.Caselli@leeds.ac.u E-mail: arturo@damir.iem.csic.e E-mail: cchandle@nrao.ed

    2009-10-01

    We present high angular resolution Plateau de Bure Interferometer images (beam of approx0.''33) of the J = 27 -> 26 line from several vibrational levels (v {sub 7} = 1 and v {sub 6} = 1) of HC{sub 3}N toward Cepheus A HW2. These images reveal the two main heating sources in the cluster: one centered in the disk collimating the HW2 radio jet (the HW2 disk), and the other associated with a hot core 0.''3 northeast HW2 (the HC). This is the first time that vibrationally excited emission of HC{sub 3}N is spatially resolved in a disk. The kinematics of this emission shows that the HW2 disk rotates following a Keplerian law. We derive the temperature profiles in the two objects from the excitation of HC{sub 3}N along the HW2 disk and the HC. These profiles reveal that both objects are centrally heated and show temperature gradients. The inner and hotter regions have temperatures of 350 +- 30 K and 270 +- 20 K for the HW2 disk and the HC, respectively. In the cooler and outer regions, the temperature drops to 250 +- 30 K in the HW2 disk, and to 220 +- 15 K in the HC. The estimated luminosity of the heating source of the HW2 disk is approx2.2 x 10{sup 4} L {sub sun}, and approx3000 L {sub sun} for the HC. The most massive protostar in the HW2 region is the powering source of the HW2 radio jet. We discuss the formation of multiple systems in this cluster. The proximity of the HC to HW2 suggests that these sources likely form a binary system of B stars, explaining the observed precession of the HW2 radio jet.

  3. New geophysical models related to heat sources in the geysers-clear lake region, California

    USGS Publications Warehouse

    Stanley, W.D.; Blakely, R.J.

    1993-01-01

    We present an updated view of the geological and geophysical complexities of the upper crust in The Geysers-Clear Lake region in order to provide additional information regarding local structures and possible heat sources. New models and ideal-body analysis of the gravity data, new electromagnetic sounding models, and arguments made from other geophysical data sets suggest that many of the geophysical anomalies may be significantly affected by rock-property and physical-state variations in the upper 7 km, and not just to 'magma' at greater depths. We developed the new geophysical models in order to better understand constraints on the location of magma bodies.

  4. Dual source heat pump

    DOEpatents

    Ecker, Amir L.; Pietsch, Joseph A.

    1982-01-01

    What is disclosed is a heat pump apparatus for conditioning a fluid characterized by a fluid handler and path for circulating the fluid in heat exchange relationship with a refrigerant fluid; at least two refrigerant heat exchangers, one for effecting heat exchange with the fluid and a second for effecting heat exchange between refrigerant and a heat exchange fluid and the ambient air; a compressor for efficiently compressing the refrigerant; at least one throttling valve for throttling liquid refrigerant; a refrigerant circuit; refrigerant; a source of heat exchange fluid; heat exchange fluid circulating device and heat exchange fluid circuit for circulating the heat exchange fluid in heat exchange relationship with the refrigerant; and valves or switches for selecting the heat exchangers and direction of flow of the refrigerant therethrough for selecting a particular mode of operation. The heat exchange fluid provides energy for defrosting the second heat exchanger when operating in the air source mode and also provides a alternate source of heat.

  5. Thulium-170 heat source

    SciTech Connect

    Walter, C.E.; Van Konynenburg, R.; Van Sant, J.H.

    1992-01-21

    This patent describes an isotopic heat source. It comprises; at least one isotopic fuel stack, comprising alternating layers of: thulium oxide; and a low atomic weight diluent for thulium oxide; a heat block defining holes into which the fuel stacks can be placed; at least one heat pipe for heat removal, with the heat pipe being positioned in the heat block in thermal connection with the fuel stack; and a structural container surrounding the heat block.

  6. Multiple source heat pump

    DOEpatents

    Ecker, Amir L.

    1983-01-01

    A heat pump apparatus for conditioning a fluid characterized by a fluid handler and path for circulating a fluid in heat exchange relationship with a refrigerant fluid, at least three refrigerant heat exchangers, one for effecting heat exchange with the fluid, a second for effecting heat exchange with a heat exchange fluid, and a third for effecting heat exchange with ambient air; a compressor for compressing the refrigerant; at least one throttling valve connected at the inlet side of a heat exchanger in which liquid refrigerant is vaporized; a refrigerant circuit; refrigerant; a source of heat exchange fluid; heat exchange fluid circuit and pump for circulating the heat exchange fluid in heat exchange relationship with the refrigerant; and valves or switches for selecting the heat exchangers and directional flow of refrigerant therethrough for selecting a particular mode of operation. Also disclosed are a variety of embodiments, modes of operation, and schematics therefor.

  7. Radioisotopic heat source

    DOEpatents

    Sayell, E.H.

    1973-10-23

    A radioisotopic heat source is described which includes a core of heat productive, radioisotopic material, an impact resistant layer of graphite surrounding said core, and a shell of iridium metal intermediate the core and the impact layer. The source may also include a compliant mat of iridium between the core and the iridium shell, as well as an outer covering of iridium metal about the entire heat source. (Official Gazette)

  8. Thulium-170 heat source

    SciTech Connect

    Walter, C.E.; Van Konynenburg, R.; VanSant, J.H.

    1990-09-06

    An isotopic heat source is formed using stacks of thin individual layers of a refractory isotopic fuel, preferably thulium oxide, alternating with layers of a low atomic weight diluent, preferably graphite. The graphite serves several functions: to act as a moderator during neutron irradiation, to minimize bremsstrahlung radiation, and to facilitate heat transfer. The fuel stacks are inserted into a heat block, which is encased in a sealed, insulated and shielded structural container. Heat pipes are inserted in the heat block and contain a working fluid. The heat pipe working fluid transfers heat from the heat block to a heat exchanger for power conversion. Single phase gas pressure controls the flow of the working fluid for maximum heat exchange and to provide passive cooling.

  9. Thulium-170 heat source

    DOEpatents

    Walter, Carl E.; Van Konynenburg, Richard; VanSant, James H.

    1992-01-01

    An isotopic heat source is formed using stacks of thin individual layers of a refractory isotopic fuel, preferably thulium oxide, alternating with layers of a low atomic weight diluent, preferably graphite. The graphite serves several functions: to act as a moderator during neutron irradiation, to minimize bremsstrahlung radiation, and to facilitate heat transfer. The fuel stacks are inserted into a heat block, which is encased in a sealed, insulated and shielded structural container. Heat pipes are inserted in the heat block and contain a working fluid. The heat pipe working fluid transfers heat from the heat block to a heat exchanger for power conversion. Single phase gas pressure controls the flow of the working fluid for maximum heat exchange and to provide passive cooling.

  10. Radioisotopic heat source

    DOEpatents

    Jones, G.J.; Selle, J.E.; Teaney, P.E.

    1975-09-30

    Disclosed is a radioisotopic heat source and method for a long life electrical generator. The source includes plutonium dioxide shards and yttrium or hafnium in a container of tantalum-tungsten-hafnium alloy, all being in a nickel alloy outer container, and subjected to heat treatment of from about 1570$sup 0$F to about 1720$sup 0$F for about one h. (auth)

  11. Regional Heat Sources and the Active and Break Phases of Boreal Summer Intraseasonal Variability

    SciTech Connect

    Annamalai, H; Sperber, K R

    2003-12-15

    The boreal summer intraseasonal variability (BSISV) associated with the 30-50 day mode is represented by the co-existence of three components, poleward propagation of convection over the Indian and tropical west Pacific longitudes and eastward propagation along the equator. The hypothesis that the three components influence each other has been investigated using observed OLR, NCEP-NCAR reanalysis, and solutions from an idealized linear model. The null hypothesis is that the three components are mutually independent. Cyclostationary EOF (CsEOF) analysis is applied on filtered OLR to extract the life-cycle of the BSISV. The dominant mode of CsEOF is significantly tied to observed rainfall over the Indian subcontinent. The components of the heating patterns from CsEOF analysis serve as prescribed forcings for the linear model. This allows us to ascertain which heat sources and sinks are instrumental in driving the large-scale monsoon circulation during the BSISV life-cycle. We identify three new findings: (1) the circulation anomalies that develop as a Rossby wave response to suppressed convection over the equatorial Indian Ocean associated with the previous break phase of the BSISV precondition the ocean-atmosphere system in the western Indian Ocean and trigger the next active phase of the BSISV, (2) the development of convection over the tropical west Pacific forces descent anomalies to the west. This, in conjunction with the weakened cross-equatorial flow due to suppressed convective anomalies over the equatorial Indian Ocean reduce the tropospheric moisture over the Arabian Sea, and promote westerly wind anomalies that do not recurve over India. As a result the low-level cyclonic vorticity shifts from India to southeast Asia and break conditions are initiated over India, and (3) the circulation anomalies forced by equatorial Indian Ocean convective anomalies significantly influence the active/break phases over the tropical west Pacific. Our model solutions support

  12. A Model for coupled heat and moisture transfer in permafrost regions of three rivers source areas, Qinghai, China

    NASA Astrophysics Data System (ADS)

    Wu, X. L.; Xiang, X. H.; Wang, C. H.; Shao, Q. Q.

    2012-04-01

    Soil freezing occurs in winter in many parts of the world. The transfer of heat and moisture in freezing and thawing soil is interrelated, and this heat and moisture transport plays an important role in hydrological activity of seasonal frozen region especially for three rivers sources area of China. Soil freezing depth and ice content in frozen zone will significantly influence runoff and groundwater recharge. The purpose of this research is to develop a numerical model to simulate water and heat movement in the soil under freezing and thawing conditions. The basic elements of the model are the heat and water flow equations, which are heat conduction equation and unsaturated soil fluid mass conservation equation. A full-implicit finite volume scheme is used to solve the coupled equations in space. The model is calibrated and verified against the observed moisture and temperature of soil during freezing and thawing period from 2005 to 2007. Different characters of heat and moisture transfer are testified, such as frozen depth, temperature field of 40 cm depth and topsoil moisture content, et al. The model is calibrated and verified against observed value, which indicate that the new model can be used successfully to simulate numerically the coupled heat and mass transfer process in permafrost regions. By simulating the runoff generation process and the driven factors of seasonal changes, the agreement illustrates that the coupled model can be used to describe the local phonemes of hydrologic activities and provide a support to the local Ecosystem services. This research was supported by the National Natural Science Foundation of China (No. 51009045; 40930635; 41001011; 41101018; 51079038), the National Key Program for Developing Basic Science (No. 2009CB421105), the Fundamental Research Funds for the Central Universities (No. 2009B06614; 2010B00414), the National Non Profit Research Program of China (No. 200905013-8; 201101024; 20101224).

  13. Regional impact of the Armenian highland as an elevated heat source: ERA-Interim reanalysis and observations

    NASA Astrophysics Data System (ADS)

    Gevorgyan, Artur; Melkonyan, Hamlet

    2015-03-01

    The heat-driven plain-plateau circulation producing strong summertime winds in Yerevan has been examined. The study indicates that the formation of plain-plateau circulation over the Armenian Highland is the combined product of large-scale and local circulations. There is significant enhancement of the westerly subtropical jet over the study region, Caspian Sea and further to the east in the upper troposphere in days with severe wind gusts in Yerevan. Further, the influence of major monsoon systems (Indian and African) on the plain-plateau circulation over the Armenian Highland is considered in this study. Both observations and ERA-Interim reanalysis data show the existence of intense heat source over the southeastern and southern parts of the Armenian Highland which produces an extra daytime warming exceeding 2.1 °C on average at the ground surface during days with severe gusts in Yerevan. This warm center is maintained through 700 hPa level and it disappears in the middle and upper troposphere. The plateau atmospheric boundary layer can extend beyond 4,000 m above mean sea level (up to the middle troposphere) during the afternoon. By contrast, exposed mountain ranges stretching along the Black and Caspian seas are characterized by significant negative temperature differences. It should be noted that ERA-Interim reanalysis data strongly underestimate the significant negative differences in mean daytime temperatures over northeastern, southeastern parts of Armenia and over Sevan Lake basin found in observed data. The results suggest intensification of the plain-plateau circulation over the Armenian Highland induced by recent surface warming over the study region. Temperature projections over the study region for the twenty-first century show that the enhancement of the plain-plateau circulation can be expected under future climate conditions.

  14. Sudurnes Regional Heating Corp.

    SciTech Connect

    Lienau, P.J.

    1996-11-01

    The Svartsengi geothermal area is close to the town of Grindavik on the Rekjanes peninsula and is part of an active fissure swarm, lined with crater-rows and open fissures and faults. The high-temperature area has an area of 2 sq. km and shows only limited signs of geothermal activity at the surface. The reservoir, however, contains lots of energy and at least 8 wells supply the Svartsengi Power Plant with steam. The steam is not useable for domestic heating purposes so that heat exchangers are used to heat cold groundwater with the steam. Some steam is also used for producing 16.4 MW{sub e} of electrical power. The article shows the distribution system piping hot water to nine towns and the Keflavik International Airport. The effluent brine from the Svartsengi Plant is disposed of into a surface pond, called the Blue Lagoon, popular to tourists and people suffering from psoriasis and other forms of eczema seeking therapeutic effects from the silica rich brine. This combined power plant and regional district heating system (cogeneration) is an interesting and unique design for the application of geothermal energy.

  15. General Purpose Heat Source Simulator

    NASA Technical Reports Server (NTRS)

    Emrich, William J., Jr.

    2008-01-01

    The General Purpose Heat Source (GPHS) project seeks to combine the development of an electrically heated, single GPHS module simulator with the evaluation of potential nuclear surface power systems. The simulator is designed to match the form, fit, and function of actual GPHS modules which normally generate heat through the radioactive decay of Pu238. The use of electrically heated modules rather than modules containing Pu238 facilitates the testing of the subsystems and systems without sacrificing the quantity and quality of the test data gathered. Current GPHS activities are centered on developing robust heater designs with sizes and weights which closely match those of actual Pu238 fueled GPHS blocks. Designs are being pursued which will allow operation up to 1100 C.

  16. Reull Vallis Source Region

    NASA Technical Reports Server (NTRS)

    2002-01-01

    [figure removed for brevity, see original site] (Released 1 July 2002) The jumbled, chaotic terrain in this THEMIS image may represent a source region for the Reull Vallis, one of the larger channel systems in the southern hemisphere of Mars. Such regions of chaos are thought to form by the catastrophic release of groundwater. If this was the case, then the water would have flowed down gradient to the south and may have contributed to the formation of the Reull Vallis. The top of the image shows two short segments of channels that are interrupted by the chaos, demonstrating that there was a channel system in place before the ground foundered to produce the chaos. One of the more intriguing features seen among the jumbled blocks are narrow ledges that vaguely resemble bath tub rings in the way they conform to the topography. Two good examples are seen running roughly left-right across the image about a fourth of the way down. At first they appear to be layers protruding from the cliff faces, but upon closer inspection a more ledge-like character is evident. Note how they appear different between the south-facing and north facing cliffs. The occurrence of one of these features on the south-facing interior rim of the largest crater in the image but nowhere else around the rim argues against the idea that the ledges are due to a layer of rock cropping out throughout the landscape. Instead, they appear more like the edges of a layer of sediment that drapes the topography. It is possible that the sediment is mixed with ice and is best preserved in the shadowed portions of the terrain. There is no easy explanation for these unusual features. They represent one more Martian enigma.

  17. Performance characteristic of thermosyphon heat pipe at radiant heat source

    NASA Astrophysics Data System (ADS)

    Hrabovský, Peter; Papučík, Štefan; Kaduchová, Katarína

    2016-06-01

    This article discusses about device, which is called heat pipe. This device is with heat source with radiant heat source. Heat pipe is device with high efficiency of heat transfer. The heat pipe, which is describe in this article is termosyphon heat pipe. The experiment with termosyphon heat pipe get a result. On the base of result, it will be in future to create mathematical model in Ansys. Thermosyphon heat pipe is made of copper and distilled water is working fluid. The significance of this experiment consists in getting of the heat transfer and performance characteristic. On the basis of measured and calculated data can be constructed the plots.

  18. General Purpose Heat Source Simulator

    NASA Technical Reports Server (NTRS)

    Emrich, Bill

    2008-01-01

    The General Purpose Heat Source (GPHS) simulator project is designed to replicate through the use of electrical heaters, the form, fit, and function of actual GPHS modules which generate heat through the radioactive decay of Pu238. The use of electrically heated modules rather than modules containing Pu238 facilitates the testing of spacecraft subsystems and systems without sacrificing the quantity and quality of the test data gathered. Previous GPHS activities are centered around developing robust heater designs with sizes and weights that closely matched those of actual Pu238 fueled GPHS blocks. These efforts were successful, although their maximum temperature capabilities were limited to around 850 C. New designs are being pursued which also replicate the sizes and weights of actual Pu238 fueled GPHS blocks but will allow operation up to 1100 C.

  19. Ion plating with an induction heating source

    NASA Technical Reports Server (NTRS)

    Spalvins, T.; Brainard, W. A.

    1976-01-01

    Induction heating is introduced as an evaporation heat source in ion plating. A bare induction coil without shielding can be directly used in the glow discharge region with no arcing. The only requirement is to utilize an rf inductive generator with low operating frequency of 75 kHz. Mechanical simplicity of the ion plating apparatus and ease of operation is a great asset for industrial applications; practically any metal such as nickel, iron, and the high temperature refractories can be evaporated and ion plated.

  20. 30 CFR 56.4500 - Heat sources.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Heat sources. 56.4500 Section 56.4500 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Installation/construction/maintenance § 56.4500 Heat sources. Heat sources capable of producing...

  1. 30 CFR 56.4500 - Heat sources.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Heat sources. 56.4500 Section 56.4500 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Installation/construction/maintenance § 56.4500 Heat sources. Heat sources capable of producing...

  2. 30 CFR 57.4500 - Heat sources.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Heat sources. 57.4500 Section 57.4500 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Installation/construction/maintenance § 57.4500 Heat sources. Heat sources capable of producing...

  3. 30 CFR 57.4500 - Heat sources.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Heat sources. 57.4500 Section 57.4500 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Installation/construction/maintenance § 57.4500 Heat sources. Heat sources capable of producing...

  4. 30 CFR 56.4500 - Heat sources.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Heat sources. 56.4500 Section 56.4500 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Installation/construction/maintenance § 56.4500 Heat sources. Heat sources capable of producing...

  5. 30 CFR 57.4500 - Heat sources.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Heat sources. 57.4500 Section 57.4500 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Installation/construction/maintenance § 57.4500 Heat sources. Heat sources capable of producing...

  6. 30 CFR 56.4500 - Heat sources.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Heat sources. 56.4500 Section 56.4500 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Installation/construction/maintenance § 56.4500 Heat sources. Heat sources capable of producing...

  7. 30 CFR 57.4500 - Heat sources.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Heat sources. 57.4500 Section 57.4500 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Installation/construction/maintenance § 57.4500 Heat sources. Heat sources capable of producing...

  8. 30 CFR 57.4500 - Heat sources.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Heat sources. 57.4500 Section 57.4500 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Installation/construction/maintenance § 57.4500 Heat sources. Heat sources capable of producing...

  9. 30 CFR 56.4500 - Heat sources.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Heat sources. 56.4500 Section 56.4500 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Installation/construction/maintenance § 56.4500 Heat sources. Heat sources capable of producing...

  10. Stress state of a plate heated by a heat source

    SciTech Connect

    Motovilovets, I.A.

    1995-11-01

    THis article presents the solution to a thermoelastic problem concerning the stress-strain of an infinite plate heated by a heat source. It is assumed that the temperature and the source of heat change linearly through the thickness of the plate. Errors made in [2,5,6] in the derivation of the thermoelastic equations of state are explained.

  11. Carbothermic reduction with parallel heat sources

    DOEpatents

    Troup, Robert L.; Stevenson, David T.

    1984-12-04

    Disclosed are apparatus and method of carbothermic direct reduction for producing an aluminum alloy from a raw material mix including aluminum oxide, silicon oxide, and carbon wherein parallel heat sources are provided by a combustion heat source and by an electrical heat source at essentially the same position in the reactor, e.g., such as at the same horizontal level in the path of a gravity-fed moving bed in a vertical reactor. The present invention includes providing at least 79% of the heat energy required in the process by the electrical heat source.

  12. Thulium heat sources for space power applications

    SciTech Connect

    Alderman, C.J.

    1992-05-01

    Reliable power supplies for use in transportation and remote systems will be an important part of space exploration terrestrial activities. A potential power source is available in the rare earth metal, thulium. Fuel sources can be produced by activating Tm-169 targets in the space station reactor. The resulting Tm-170 heat sources can be used in thermoelectric generators to power instrumentation and telecommunications located at remote sites such as weather stations. As the heat source in a dynamic Sterling or Brayton cycle system, the heat source can provide a lightweight power source for rovers or other terrestrial transportation systems.

  13. Thulium heat sources for space power application

    SciTech Connect

    Alderman, C.J. )

    1993-01-15

    Reliable electrical power supplies for use in transportation and remote systems will be an important part of space exploration activities on planet surfaces. A potential power source is available through the use of thulium, a rare earth metal. Heat sources can be produced by neutron activation of naturally occurring thulium (Tm-169) targets in the base station nuclear power reactor. The resulting Tm-170 heat sources can be used in thermoelectric generators to power instrumentation and telecommunications systems located at remote sites. Combined with a dynamic Sterling or Brayton cycle conversion system, the heat source can power a lightweight electrical source for rovers or other surface transportation systems.

  14. Heat source reentry vehicle design study

    NASA Technical Reports Server (NTRS)

    Ryan, R. L.

    1971-01-01

    The design details are presented of a flight-type heat source reentry vehicle and heat exchanger compatible with the isotope Brayton power conversion system. The reference reentry vehicle and heat exchanger were modified, orbital and superorbital capability was assessed, and a complete set of detail design layout drawings were provided.

  15. Mini-Brayton heat source assembly development

    NASA Technical Reports Server (NTRS)

    Wein, D.; Zimmerman, W. F.

    1978-01-01

    The work accomplished on the Mini-Brayton Heat Source Assembly program is summarized. Required technologies to design, fabricate and assemble components for a high temperature Heat Source Assembly (HSA) which would generate and transfer the thermal energy for a spaceborne Brayton Isotope Power System (BIPS) were developed.

  16. The heat treating source book

    SciTech Connect

    Gupton, P.S.

    1986-01-01

    The first section of this book reviews current trends and is followed by an article describing how to design for lower cost and high-quality heat treatment. Two separate sections deal with ferrous materials and non-ferrous metals. Coverage includes stress-relief heat treating, normalizing and cold treating of steel; ultrahigh-strength steels; tool steels; maraging steels; austenitic stainless steels and cast irons, as well as aluminum alloys, titanium and its alloys, nickel-base superalloys, special purpose alloys and lead and its alloys. Other topics discussed are carburizing, carbonitriding and nitriding; vacuum methods; salt bath processing; methods of measuring case depth; and atmosphere control and nitrogen as all-purpose atmosphere. Also, information is provided on energy-efficient operations, production systems, selecting and handling quenching fluids, furnace control instrumentation, and guidelines for heat treating powdered metal parts.

  17. Pacific Regional Solar Heating Handbook. Second Edition.

    ERIC Educational Resources Information Center

    Writers' Development Trust, Toronto (Ontario).

    This handbook is intended as a guide for engineers, architects, and individuals familiar with heating and ventilating applications who wish to design a solar heating system for a residential or small commercial building in the Pacific Coast Region. The climate of the region is discussed by selected cities in terms of the effect of climate on solar…

  18. Advanced radioisotope heat source for Stirling Engines

    NASA Astrophysics Data System (ADS)

    Dobry, T. J.; Walberg, G.

    2001-02-01

    The heat exchanger on a Stirling Engine requires a thermal energy transfer from a heat source to the engine through a very limited area on the heater head circumference. Designing an effective means to assure maximum transfer efficiency is challenging. A single General Purpose Heat Source (GPHS), which has been qualified for space operations, would satisfy thermal requirements for a single Stirling Engine that would produce 55 electrical watts. However, it is not efficient to transfer its thermal energy to the engine heat exchanger from its rectangular geometry. This paper describes a conceptual design of a heat source to improve energy transfer for Stirling Engines that may be deployed to power instrumentation on space missions. .

  19. Pulsating aurora: Source region & morphology

    NASA Astrophysics Data System (ADS)

    Jaynes, Allison

    Pulsating aurora, a common phenomenon in the polar night sky, offers a unique opportunity to study the precipitating particle populations responsible for this subtle yet fascinating display of lights. The conjecture that the source of these electrons originates near the equator, made decades ago, has now been confirmed using in-situ measurements. In this thesis, we present these results that compare the frequencies of equatorial electron flux pulsations and pulsating aurora luminosity fluctuations at the ionospheric footprint. We use simultaneous satellite-based data from GOES 13 and ground-based data from the THEMIS allsky imager array to show that there is a direct correlation between luminosity fluctuations near the ground and particle pulsations in equatorial space; the source region of the pulsating aurora. Pulsating aurora almost exclusively occurs embedded within a region of diffuse aurora. By studying the two particle populations, one can contribute to the theory behind auroral pulsations. The interplay between the two auroral types, and the systems that control them, are not yet well known. We analyze ground optical observations of pulsating aurora events to attempt to characterize the relationship between the two types of auroral precipitation. Pulsating aurora is a significant component of energy transfer within the framework of magnetosphere-ionosphere coupling. Further study of the morphology, total energy deposition, and the pulsation mechanism of pulsating aurora is key to a better understanding of our earth-sun system.

  20. REGIONAL AIR POLLUTION STUDY: HEAT EMISSION INVENTORY

    EPA Science Inventory

    As part of the St. Louis Regional Air Pollution Study (RAPS), a heat emission inventory has been assembled. Heat emissions to the atmosphere originate, directly or indirectly, from the combustion of fossil fuels (there are no nuclear plants in the St. Louis AQCR). With the except...

  1. Characterization and modeling of the heat source

    SciTech Connect

    Glickstein, S.S.; Friedman, E.

    1993-10-01

    A description of the input energy source is basic to any numerical modeling formulation designed to predict the outcome of the welding process. The source is fundamental and unique to each joining process. The resultant output of any numerical model will be affected by the initial description of both the magnitude and distribution of the input energy of the heat source. Thus, calculated weld shape, residual stresses, weld distortion, cooling rates, metallurgical structure, material changes due to excessive temperatures and potential weld defects are all influenced by the initial characterization of the heat source. Understandings of both the physics and the mathematical formulation of these sources are essential for describing the input energy distribution. This section provides a brief review of the physical phenomena that influence the input energy distributions and discusses several different models of heat sources that have been used in simulating arc welding, high energy density welding and resistance welding processes. Both simplified and detailed models of the heat source are discussed.

  2. Effect of the Heat Pipe Adiabatic Region.

    PubMed

    Brahim, Taoufik; Jemni, Abdelmajid

    2014-04-01

    The main motivation of conducting this work is to present a rigorous analysis and investigation of the potential effect of the heat pipe adiabatic region on the flow and heat transfer performance of a heat pipe under varying evaporator and condenser conditions. A two-dimensional steady-state model for a cylindrical heat pipe coupling, for both regions, is presented, where the flow of the fluid in the porous structure is described by Darcy-Brinkman-Forchheimer model which accounts for the boundary and inertial effects. The model is solved numerically by using the finite volumes method, and a fortran code was developed to solve the system of equations obtained. The results show that a phase change can occur in the adiabatic region due to temperature gradient created in the porous structure as the heat input increases and the heat pipe boundary conditions change. A recirculation zone may be created at the condenser end section. The effect of the heat transfer rate on the vapor radial velocities and the performance of the heat pipe are discussed. PMID:24895467

  3. Conjugate Heat Transfer in a Closed Volume with the Local Heat Sources and Non-Uniform Heat Dissipation on the Boundaries of Heat Conducting Walls

    NASA Astrophysics Data System (ADS)

    Maksimov, Vyacheslav I.; Nagornova, Tatiana A.; Glazyrin, Viktor P.

    2016-02-01

    Is solved the problem of heat transfer in the closed volume, limited by heat-conducting walls, with the local source of heat emission and the heterogeneous conditions of heat sink on the outer boundaries of solution area. The problem of convective heat transfer is solved with using a system of differential Navier-Stokes equations in the Boussinesq approximation. The simulation of turbulent flow conditions of heated air is carried out within the framework to k-ɛ model. On the basis the analysis of the obtained temperature field and the contour lines of stream functions is made conclusion about the essential transiency of the process in question. The obtained values of temperatures and speeds in different sections of region illustrate turbulence of the process. Are investigated laws governing the formation of temperature fields in closed areas with a local heat emission source under the conditions of intensive local heat sink into environment and accumulation of heat in the enclosing constructions.

  4. Application of Heat Pipes in Cold Region

    NASA Astrophysics Data System (ADS)

    Mochizuki, Masataka

    Recently, there has been put into practical use of heat pipes as space application, electronics cooling, and waste heat recovery. Especially, the low temperature heat pipe which can be used in below atmospheric temperature are also actively developed and applied in terrestrial field. These are based on utilization of natural energy in cold region. This paper is described about application of snow melting and deicing system on a road and roof, snow damage prevention system for electric pole branch wire, artificial permafrost storage system as a reverse utilization of cold atmosphere, and cryo-anchor applied in Alaska and northern Canada.

  5. Circulatory heat sources for canine respiratory heat exchange.

    PubMed Central

    Solway, J; Leff, A R; Dreshaj, I; Munoz, N M; Ingenito, E P; Michaels, D; Ingram, R H; Drazen, J M

    1986-01-01

    We assessed the roles of the pulmonary and bronchial circulations as potential heat sources to the pulmonary airways during respiratory heat loss, by observing the changes in airstream temperature that accompanied temporary occlusion of the pulmonary or bronchial circulations. Baseline end-expiratory and end-inspiratory airstream temperatures were 35.4 +/- 0.2 degrees C (SEM) and 30.9 +/- 0.3 degrees C, respectively, among all trials. With occlusion of the lower lobe pulmonary arteries for 3 min ipsilateral end-expiratory and end-inspiratory airstream temperatures fell by 2.8 +/- 0.2 and 1.1 +/- 0.2 degrees C, respectively, during hyperpnea with room temperature air, and by 3.5 +/- 0.5 and 1.8 +/- 0.2 degrees C, respectively, during hyperpnea with frigid air. In marked contrast, interruption of the bronchial circulation for 3 min had no effect on airstream temperatures. These data indicate that under these conditions, the pulmonary circulation, but not the bronchial circulation, serves as an important local heat source for respiratory heat exchange within the pulmonary airways. Images PMID:3760181

  6. Models of Impulsively Heated Solar Active Regions

    NASA Astrophysics Data System (ADS)

    Airapetian, Vladimir; Klimchuk, J.

    2009-05-01

    A number of attempts to model solar active regions with steady coronal heating have been modestly successful at reproducing the observed soft X-ray emission, but they fail dramatically at explaining EUV observations. Since impulsive heating (nanoflare) models can reproduce individual EUV loops, it seems reasonable to consider that entire active regions are impulsively heated. However, nanoflares are characterized by many parameters, such as magnitude, duration, and time delay between successive events, and these parameters may depend on the strength of the magnetic field or the length of field lines, for example, so a wide range of active region models must be examined. We have recently begun such a study. Each model begins with a magnetic "skeleton” obtained by extrapolating an observed photospheric magnetogram into the corona. Field lines are populated with plasma using our highly efficient hydro code called Enthalpy Based Thermal Evolution of Loops (EBTEL). We then produce synthetic images corresponding to emission line or broad-band observations. By determining which set of nanoflare parameters best reproduces actual observations, we hope to constrain the properties of the heating and ultimately to reveal the physical mechanism. We here report on the initial progress of our study.

  7. Source regions of the solar wind

    NASA Technical Reports Server (NTRS)

    Wang, Y.-M.; Sheeley, N. R., Jr.

    1995-01-01

    Using Skylab XUV data, we examine some properties of the source regions of the solar wind. In particular, we discuss the physical nature of polar plumes and their relationship to the polar wind, the nature of the source regions of the slow solar wind, and the relationship between abundance anomalies (the FIP effect) determined from the Skylab data and the sources of fast and slow wind.

  8. Source Region Identification Using Kernel Smoothing

    EPA Science Inventory

    As described in this paper, Nonparametric Wind Regression is a source-to-receptor source apportionment model that can be used to identify and quantify the impact of possible source regions of pollutants as defined by wind direction sectors. It is described in detail with an exam...

  9. Modified Beamformers for Coherent Source Region Suppression

    PubMed Central

    Sekihara, Kensuke; Nagarajan, Srikantan S.

    2011-01-01

    Many tomographic source localization algorithms used in biomagnetic imaging assume, explicitly or sometimes implicitly, that the source activity at different brain locations are either independent or that the correlation structure between sources is known. Among these algorithms is a class of adaptive spatial filters known as beamformers, which have superior spatiotemporal resolution abilities. The performance of beamformers is robust to weakly coherent sources. However, these algorithms are extremely sensitive to the presence of strongly coherent sources. A frequent mode of failure in beamformers occurs with reconstruction of auditory evoked fields (AEFs), in which bilateral auditory cortices are highly coherent in their activation. Here, we present a novel beamformer that suppresses activation from regions with interfering coherent sources. First, a volume containing the interfering sources is defined. The lead field matrix for this volume is computed and reduced into a few significant columns using singular value decomposition (SVD). A vector beamformer is then constructed by rejecting the contribution of sources in the suppression region while allowing for source reconstruction at other specified regions. Performance of this algorithm was first validated with simulated data. Subsequent tests of this modified beamformer were performed on bilateral AEF data. An unmodified vector beamformer using whole head coverage misplaces the source medially. After defining a suppression region containing the temporal cortex on one side, the described method consistently results in clear focal activations at expected regions of the contralateral superior temporal plane. PMID:16830939

  10. Convection of ion cyclotron waves to ion-heating regions

    SciTech Connect

    Roennmark, K.; Andre, M. )

    1991-10-01

    Low-frequency waves associated with ion conics have been observed in the central plasma sheet, in a region where there are no obvious sources of free energy that could destabilize these waves locally. The authors consider ion cyclotron waves generated in the equatorial plane by a proton temperature anisotropy and use computed growth rates to create a model wave distribution. Using ray tracing and conservation of the wave distribution function along phase space rays, they then map the wave intensities form the equatorial plane to the top of the ion-heating region. They find that the spectral density at a geocentric distance of 2.8 R{sub E} will be about 10 times higher than that in the equatorial region. Thus, convection from the equatorial plane could explain the observed spectral density of 10{sup {minus}6} V{sup 2} m{sup {minus}2} Hz{sup {minus}1} and the associated oxygen ion heating.

  11. Thermoelectricity without absorbing energy from the heat sources

    NASA Astrophysics Data System (ADS)

    Whitney, Robert S.; Sánchez, Rafael; Haupt, Federica; Splettstoesser, Janine

    2016-01-01

    We analyze the power output of a quantum dot machine coupled to two electronic reservoirs via thermoelectric contacts, and to two thermal reservoirs - one hot and one cold. This machine is a nanoscale analogue of a conventional thermocouple heat-engine, in which the active region being heated is unavoidably also exchanging heat with its cold environment. Heat exchange between the dot and the thermal reservoirs is treated as a capacitive coupling to electronic fluctuations in localized levels, modeled as two additional quantum dots. The resulting multiple-dot setup is described using a master equation approach. We observe an "exotic" power generation, which remains finite even when the heat absorbed from the thermal reservoirs is zero (in other words the heat coming from the hot reservoir all escapes into the cold environment). This effect can be understood in terms of a non-local effect in which the heat flow from heat source to the cold environment generates power via a mechanism which we refer to as Coulomb heat drag. It relies on the fact that there is no relaxation in the quantum dot system, so electrons within it have a non-thermal energy distribution. More poetically, one can say that we find a spatial separation of the first-law of thermodynamics (heat to work conversion) from the second-law of thermodynamics (generation of entropy). We present circumstances in which this non-thermal system can generate more power than any conventional macroscopic thermocouple (with local thermalization), even when the latter works with Carnot efficiency.

  12. Reprint of : Thermoelectricity without absorbing energy from the heat sources

    NASA Astrophysics Data System (ADS)

    Whitney, Robert S.; Sánchez, Rafael; Haupt, Federica; Splettstoesser, Janine

    2016-08-01

    We analyze the power output of a quantum dot machine coupled to two electronic reservoirs via thermoelectric contacts, and to two thermal reservoirs - one hot and one cold. This machine is a nanoscale analogue of a conventional thermocouple heat-engine, in which the active region being heated is unavoidably also exchanging heat with its cold environment. Heat exchange between the dot and the thermal reservoirs is treated as a capacitive coupling to electronic fluctuations in localized levels, modeled as two additional quantum dots. The resulting multiple-dot setup is described using a master equation approach. We observe an "exotic" power generation, which remains finite even when the heat absorbed from the thermal reservoirs is zero (in other words the heat coming from the hot reservoir all escapes into the cold environment). This effect can be understood in terms of a non-local effect in which the heat flow from heat source to the cold environment generates power via a mechanism which we refer to as Coulomb heat drag. It relies on the fact that there is no relaxation in the quantum dot system, so electrons within it have a non-thermal energy distribution. More poetically, one can say that we find a spatial separation of the first-law of thermodynamics (heat to work conversion) from the second-law of thermodynamics (generation of entropy). We present circumstances in which this non-thermal system can generate more power than any conventional macroscopic thermocouple (with local thermalization), even when the latter works with Carnot efficiency.

  13. 21 CFR 872.6475 - Heat source for bleaching teeth.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Heat source for bleaching teeth. 872.6475 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6475 Heat source for bleaching teeth. (a) Identification. A heat source for bleaching teeth is an AC-powered device that consists of...

  14. 21 CFR 872.6475 - Heat source for bleaching teeth.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Heat source for bleaching teeth. 872.6475 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6475 Heat source for bleaching teeth. (a) Identification. A heat source for bleaching teeth is an AC-powered device that consists of...

  15. 21 CFR 872.6475 - Heat source for bleaching teeth.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Heat source for bleaching teeth. 872.6475 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6475 Heat source for bleaching teeth. (a) Identification. A heat source for bleaching teeth is an AC-powered device that consists of...

  16. 21 CFR 872.6475 - Heat source for bleaching teeth.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Heat source for bleaching teeth. 872.6475 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6475 Heat source for bleaching teeth. (a) Identification. A heat source for bleaching teeth is an AC-powered device that consists of...

  17. 21 CFR 872.6475 - Heat source for bleaching teeth.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Heat source for bleaching teeth. 872.6475 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6475 Heat source for bleaching teeth. (a) Identification. A heat source for bleaching teeth is an AC-powered device that consists of...

  18. Optimal Ground Source Heat Pump System Design

    SciTech Connect

    Ozbek, Metin; Yavuzturk, Cy; Pinder, George

    2015-04-15

    Despite the facts that GSHPs first gained popularity as early as the 1940’s and they can achieve 30 to 60 percent in energy savings and carbon emission reductions relative to conventional HVAC systems, the use of geothermal energy in the U.S. has been less than 1 percent of the total energy consumption. The key barriers preventing this technically-mature technology from reaching its full commercial potential have been its high installation cost and limited consumer knowledge and trust in GSHP systems to deliver the technology in a cost-effective manner in the market place. Led by ENVIRON, with support from University Hartford and University of Vermont, the team developed and tested a software-based a decision making tool (‘OptGSHP’) for the least-cost design of ground-source heat pump (‘GSHP’) systems. OptGSHP combines state of the art optimization algorithms with GSHP-specific HVAC and groundwater flow and heat transport simulation. The particular strength of OptGSHP is in integrating heat transport due to groundwater flow into the design, which most of the GSHP designs do not get credit for and therefore are overdesigned.

  19. Electron cyclotron resonance heating by magnetic filter field in a negative hydrogen ion source.

    PubMed

    Kim, June Young; Cho, Won-Hwi; Dang, Jeong-Jeung; Chung, Kyoung-Jae; Hwang, Y S

    2016-02-01

    The influence of magnetic filter field on plasma properties in the heating region has been investigated in a planar-type inductively coupled radio-frequency (RF) H(-) ion source. Besides filtering high energy electrons near the extraction region, the magnetic filter field is clearly observed to increase the electron temperature in the heating region at low pressure discharge. With increasing the operating pressure, enhancement of electron temperature in the heating region is reduced. The possibility of electron cyclotron resonance (ECR) heating in the heating region due to stray magnetic field generated by a filter magnet located at the extraction region is examined. It is found that ECR heating by RF wave field in the discharge region, where the strength of an axial magnetic field is approximately ∼4.8 G, can effectively heat low energy electrons. Depletion of low energy electrons in the electron energy distribution function measured at the heating region supports the occurrence of ECR heating. The present study suggests that addition of axial magnetic field as small as several G by an external electromagnet or permanent magnets can greatly increase the generation of highly ro-vibrationally excited hydrogen molecules in the heating region, thus improving the performance of H(-) ion generation in volume-produced negative hydrogen ion sources. PMID:26931999

  20. Electron cyclotron resonance heating by magnetic filter field in a negative hydrogen ion source

    NASA Astrophysics Data System (ADS)

    Kim, June Young; Cho, Won-Hwi; Dang, Jeong-Jeung; Chung, Kyoung-Jae; Hwang, Y. S.

    2016-02-01

    The influence of magnetic filter field on plasma properties in the heating region has been investigated in a planar-type inductively coupled radio-frequency (RF) H- ion source. Besides filtering high energy electrons near the extraction region, the magnetic filter field is clearly observed to increase the electron temperature in the heating region at low pressure discharge. With increasing the operating pressure, enhancement of electron temperature in the heating region is reduced. The possibility of electron cyclotron resonance (ECR) heating in the heating region due to stray magnetic field generated by a filter magnet located at the extraction region is examined. It is found that ECR heating by RF wave field in the discharge region, where the strength of an axial magnetic field is approximately ˜4.8 G, can effectively heat low energy electrons. Depletion of low energy electrons in the electron energy distribution function measured at the heating region supports the occurrence of ECR heating. The present study suggests that addition of axial magnetic field as small as several G by an external electromagnet or permanent magnets can greatly increase the generation of highly ro-vibrationally excited hydrogen molecules in the heating region, thus improving the performance of H- ion generation in volume-produced negative hydrogen ion sources.

  1. Alternative Radioisotopes for Heat and Power Sources

    NASA Astrophysics Data System (ADS)

    Tinsley, T.; Sarsfield, M.; Rice, T.

    Production of 238Pu requires considerable facilities including a nuclear reactor and reprocessing plants that are very expensive to build and operate. Thus, a more economical alternative is very attractive to the industry. There are many alternative radioisotopes that exist but few that satisfy the criteria of performance, availability and cost to produce. Any alternative to 238Pu must exist in a chemical form that is compatible with the materials required to safely encapsulate the heat source at the high temperatures of operation and potential launch failure scenarios. The chemical form must also have suitable thermal properties to ensure maximum energy conversion efficiencies when integrated into radioisotope thermoelectric generators over the required mission durations. In addition, the radiation dose must be low enough for operators during production and not so prohibitive that excessive shielding mass is required on the space craft. This paper will focus on the preferred European alternative of 241Am, and the issues that will need to be addressed.

  2. Desalination using low grade heat sources

    NASA Astrophysics Data System (ADS)

    Gude, Veera Gnaneswar

    A new, low temperature, energy-efficient and sustainable desalination system has been developed in this research. This system operates under near-vacuum conditions created by exploiting natural means of gravity and barometric pressure head. The system can be driven by low grade heat sources such as solar energy or waste heat streams. Both theoretical and experimental studies were conducted under this research to evaluate and demonstrate the feasibility of the proposed process. Theoretical studies included thermodynamic analysis and process modeling to evaluate the performance of the process using the following alternate energy sources for driving the process: solar thermal energy, solar photovoltaic/thermal energy, geothermal energy, and process waste heat emissions. Experimental studies included prototype scale demonstration of the process using grid power as well as solar photovoltaic/thermal sources. Finally, the feasibility of the process in reclaiming potable-quality water from the effluent of the city wastewater treatment plant was studied. The following results have been obtained from theoretical analysis and modeling: (1) The proposed process can produce up to 8 L/d of freshwater for 1 m2 area of solar collector and evaporation chamber respectively with a specific energy requirement of 3122 kJ for 1 kg of freshwater production. (2) Photovoltaic/thermal (PV/T) energy can produce up to 200 L/d of freshwater with a 25 m2 PV/T module which meets the electricity needs of 21 kWh/d of a typical household as well. This configuration requires a specific energy of 3122 kJ for 1 kg of freshwater production. (3) 100 kg/hr of geothermal water at 60°C as heat source can produce up to 60 L/d of freshwater with a specific energy requirement of 3078 kJ for 1 kg of freshwater production. (4) Waste heat released from an air conditioning system rated at 3.25 kW cooling, can produce up to 125 L/d of freshwater. This configuration requires an additional energy of 208 kJ/kg of

  3. Investigation of Vapour Chamber Performance with a Concentrated Heat Source

    NASA Astrophysics Data System (ADS)

    Ravache, E.; Siedel, S.; Kempers, R.; Robinson, A. J.

    2014-07-01

    This work aims to characterize the performance of a commercially available solid heat sink (SHS) and a vapour chamber heat sink (VCHS) with a small localized heat source. The heat sinks were tested under forced convection conditions in a dedicated wind tunnel. Heat transfer and temperature measurements facilitated the estimation of the source-to-sink thermal resistance whilst thermal imaging on the air side of the heat sink was used to gauge the level of heat spreading. The results indicate that the VCHS was capable of spreading the heat from the localized source over a greater surface area of the heat sink compared with the SHS. However, the improved spreading resistance of the VCHS was offset by the additional contact resistance and/or the thermal resistance of the internal wick structure resulting in a source-to-sink thermal resistance and heater temperature which was commensurate with the SHS. As a result there was no thermal benefit of the VCHS.

  4. Regional heat flow variations in the northern Michigan and Lake Superior region determined using the silica heat flow estimator

    USGS Publications Warehouse

    Vugrinovich, R.

    1987-01-01

    Conventional heat flow data are sparse for northern Michigan. The groundwater silica heat flow estimator expands the database sufficiently to allow regional variations in heat flow to be examined. Heat flow shows a pattern of alternating highs and lows trending ESE across the Upper Peninsula and Lake Superior. The informal names given to these features, their characteristic heat flow and inferred causes are listed: {A table is presented} The results suggest that, for the study area, regional variations in heat flow cannot be interpreted solely in terms of regional variations of the heat generation rate of basement rocks. ?? 1987.

  5. Ground-source Heat Pumps Applied to Commercial Buildings

    SciTech Connect

    Parker, Steven A.; Hadley, Donald L.

    2009-07-14

    Ground-source heat pumps can provide an energy-efficient, cost-effective way to heat and cool commercial facilities. While ground-source heat pumps are well established in the residential sector, their application in larger, commercial-style, facilities is lagging, in part because of a lack of experience with the technology by those in decision-making positions. Through the use of a ground-coupling system, a conventional water-source heat pump design is transformed to a unique means of utilizing thermodynamic properties of earth and groundwater for efficient operation throughout the year in most climates. In essence, the ground (or groundwater) serves as a heat source during winter operation and a heat sink for summer cooling. Many varieties in design are available, so the technology can be adapted to almost any site. Ground-source heat pump systems can be used widely in commercial-building applications and, with proper installation, offer great potential for the commercial sector, where increased efficiency and reduced heating and cooling costs are important. Ground-source heat pump systems require less refrigerant than conventional air-source heat pumps or air-conditioning systems, with the exception of direct-expansion-type ground-source heat pump systems. This chapter provides information and procedures that an energy manager can use to evaluate most ground-source heat pump applications. Ground-source heat pump operation, system types, design variations, energy savings, and other benefits are explained. Guidelines are provided for appropriate application and installation. Two case studies are presented to give the reader a sense of the actual costs and energy savings. A list of manufacturers and references for further reading are included for prospective users who have specific or highly technical questions not fully addressed in this chapter. Sample case spreadsheets are provided in Appendix A. Additional appendixes provide other information on the ground-source

  6. Irregular spacing of heat sources for treating hydrocarbon containing formations

    DOEpatents

    Miller, David Scott; Uwechue, Uzo Philip

    2012-06-12

    A method for treating a hydrocarbon containing formation includes providing heat input to a first section of the formation from one or more heat sources located in the first section. Fluids are produced from the first section through a production well located at or near the center of the first section. The heat sources are configured such that the average heat input per volume of formation in the first section increases with distance from the production well.

  7. Thulium heat source: IR D project 91-031

    SciTech Connect

    Walter, C.E.; Kammeraad, J.E.; Newman, J.G.; Van Konynenburg, R.; VanSant, J.H.

    1991-04-10

    The goal of the Thulium Heat Source study is to determine the performance capability and evaluate the safety and environmental aspects of a thulium-170 heat source. Our approach is to study parametrically the performance of thulium-170 heat source designs in the power range of 5--50 kW{sub th}. At least three heat source designs will be characterized in this power range and integrated with various power conversion subsystems to assess their performance, mass, and volume. We will determine shielding requirements, and consider the safety and environmental aspects of their use.

  8. Passive rejection of heat from an isotope heat source through an open door

    NASA Technical Reports Server (NTRS)

    Burns, R. K.

    1971-01-01

    The isotope heat-source design for a Brayton power system includes a door in the thermal insulation through which the heat can be passively rejected to space when the power system is not operating. The results of an analysis to predict the heat-source surface temperature and the heat-source heat-exchanger temperature during passive heat rejection as a function of insulation door opening angle are presented. They show that for a door opening angle greater than 20 deg, the temperatures are less than the steady-state temperatures during power system operation.

  9. The Source of Alfven Waves That Heat the Solar Corona

    NASA Technical Reports Server (NTRS)

    Ruzmaikin, A.; Berger, M. A.

    1998-01-01

    We suggest a source for high-frequency Alfven waves invoked in coronal heating and acceleration of the solar wind. The source is associated with small-scale magnetic loops in the chromospheric network.

  10. Radiant heat source, vacuum bag, provide portable bonding oven

    NASA Technical Reports Server (NTRS)

    Nicholls, A. H.

    1967-01-01

    Portable bonding oven is formed to any desired size or configuration to attach doublers and brackets to the surfaces of large structures. A radiant heat source is used in combination with a heat resistant transport vacuum bag and a black heat absorbing cloth.

  11. Heating the sun's lower transition region with fine-scale electric currents

    NASA Technical Reports Server (NTRS)

    Rabin, D.; Moore, R.

    1984-01-01

    Analytical and observational data are presented to show that the lower transition zone, a 100 km thick region at 10,000-200,000 K between the solar chromosphere and corona, is heated by local electric currents. The study was spurred by correlations between the enhanced atmospheric heating and magnetospheric flux in the chromospheric network and active regions. Field aligned current heated flux loops are asserted to mainly reside in and make up most of the transition region. It is shown that thermal conduction from the sides of hot gas columns generated by the current dissipation is the source of the observed temperature distribution in the transition regions.

  12. Loop Heat Pipe Operation Using Heat Source Temperature for Set Point Control

    NASA Technical Reports Server (NTRS)

    Ku, Jentung; Paiva, Kleber; Mantelli, Marcia

    2011-01-01

    The LHP operating temperature is governed by the saturation temperature of its reservoir. Controlling the reservoir saturation temperature is commonly accomplished by cold biasing the reservoir and using electrical heaters to provide the required control power. Using this method, the loop operating temperature can be controlled within +/- 0.5K. However, because of the thermal resistance that exists between the heat source and the LHP evaporator, the heat source temperature will vary with its heat output even if LHP operating temperature is kept constant. Since maintaining a constant heat source temperature is of most interest, a question often raised is whether the heat source temperature can be used for LHP set point temperature control. A test program with a miniature LHP has been carried out to investigate the effects on the LHP operation when the control temperature sensor is placed on the heat source instead of the reservoir. In these tests, the LHP reservoir is cold-biased and is heated by a control heater. Tests results show that it is feasible to use the heat source temperature for feedback control of the LHP operation. Using this method, the heat source temperature can be maintained within a tight range for moderate and high powers. At low powers, however, temperature oscillations may occur due to interactions among the reservoir control heater power, the heat source mass, and the heat output from the heat source. In addition, the heat source temperature could temporarily deviate from its set point during fast thermal transients. The implication is that more sophisticated feedback control algorithms need to be implemented for LHP transient operation when the heat source temperature is used for feedback control.

  13. Heat-source specification 500 watt(e) RTG

    SciTech Connect

    Not Available

    1983-02-01

    This specification establishes the requirements for a /sup 90/SrF/sub 2/ heat source and its fuel capsule for application in a 500 W(e) thermoelectric generator. The specification covers: fuel composition and quantity; the Hastelloy S fuel capsule material and fabrication; and the quality assurance requirements for the assembled heat source. (LCL)

  14. Loop Heat Pipe Operation Using Heat Source Temperature for Set Point Control

    NASA Technical Reports Server (NTRS)

    Ku, Jentung; Paiva, Kleber; Mantelli, Marcia

    2011-01-01

    Loop heat pipes (LHPs) have been used for thermal control of several NASA and commercial orbiting spacecraft. The LHP operating temperature is governed by the saturation temperature of its compensation chamber (CC). Most LHPs use the CC temperature for feedback control of its operating temperature. There exists a thermal resistance between the heat source to be cooled by the LHP and the LHP's CC. Even if the CC set point temperature is controlled precisely, the heat source temperature will still vary with its heat output. For most applications, controlling the heat source temperature is of most interest. A logical question to ask is: "Can the heat source temperature be used for feedback control of the LHP operation?" A test program has been implemented to answer the above question. Objective is to investigate the LHP performance using the CC temperature and the heat source temperature for feedback control

  15. Effects of a Ground Source Heat Pump in Discontinuous Permafrost

    NASA Astrophysics Data System (ADS)

    Peterson, R.; Garber-Slaght, R.; Daanen, R. P.

    2015-12-01

    A ground source heat pump (GSHP) was installed in a discontinuous permafrost region of Fairbanks Alaska in 2013 with the primary aim of determining the effect of different ground cover options on the long-term subterranean temperature regime. Three different surface treatments were applied to separate loops of the GSHP; grass, sand, and gravel, and temperature monitoring was established at several depths above and below the heat sink loops. The GSHP has been actively utilized to supplement the heat in a hydronic heating system of a neighboring 5000 ft2 research facility. The ground immediately surrounding the GSHP was not permafrost when initially installed. Numerical modeling simulations were used to predict the long-term ground temperature regime surrounding the GSHP loops, and results indicate that permafrost would begin to form after the first year. A pseudo-steady state temperature regime would establish in approximately 8 years with a yearly fluctuation of -14°C to -2°C. Simulations also indicate that permafrost could be prevented with a 15 W/m recharge during the summer, such as from a solar thermal system. The ground surface treatments have negligible effect on the ground temperature below 1 meter and therefore have no long-term effect on the active region the GSHP. Data collected from thermistors in the two years since installation indicate that permafrost has not yet been established, although the ground is now becoming seasonally frozen due to the GSHP energy removal. Yearly average temperatures are declining, and extrapolation indicates that permafrost will establish in future years. The GSHP coefficient of performance (COP) was initially 3.6 and is declining with the decreasing ground temperatures. Economic modeling indicates that the system may become uneconomical in future years, although volatile energy costs have a substantial effect of the prediction.

  16. An analysis of the vapor flow and the heat conduction through the liquid-wick and pipe wall in a heat pipe with single or multiple heat sources

    NASA Technical Reports Server (NTRS)

    Chen, Ming-Ming; Faghri, Amir

    1990-01-01

    A numerical analysis is presented for the overall performance of heat pipes with single or multiple heat sources. The analysis includes the heat conduction in the wall and liquid-wick regions as well as the compressibility effect of the vapor inside the heat pipe. The two-dimensional elliptic governing equations in conjunction with the thermodynamic equilibrium relation and appropriate boundary conditions are solved numerically. The solutions are in agreement with existing experimental data for the vapor and wall temperatures at both low and high operating temperatures.

  17. Ground Source Heat Pump Computational Results

    DOE Data Explorer

    James Menart

    2013-07-31

    This data submission includes simulation results for ground loop heat pump systems located in 6 different cities across the United States. The cities are Boston, MA, Dayton, OH, Omaha, NE, Orlando, FL, Sacramento, CA, and St. Paul, MN. These results were obtained from the two-dimensional geothermal computer code called GEO2D. GEO2D was written as part of this DOE funded grant. The results included in this submission for each of the 6 cities listed above are: 1) specific information on the building being heated or cooled by the ground loop geothermal system, 2) some extreme values for the building heating and cooling loads during the year, 3) the inputs required to carry out the simulation, 4) a plot of the hourly building heating and cooling loads throughout the year, 5) a plot of the fluid temperature exiting the ground loop for a 20 year period, 6) a plot of the heat exchange between the ground loop and the ground for a 20 year period, and 7) ground and ground loop temperature contour plots at different times of the year for the 20 year period.

  18. Monitoring and evaluating ground-source heat pump. Final report

    SciTech Connect

    Stoltz, S.V.; Cade, D.; Mason, G.

    1996-05-01

    This report presents the measured performance of four advanced residential ground-source heat pump (GSHP) systems. The GSHP systems were developed by WaterFurnace International to minimize the need for electric resistance backup heating and featured multiple speed compressors, supplemental water heating, and at most sites, multiple-speed fans. Detailed data collected for a complete year starting in June 1994 shows that the advanced design is capable of maintaining comfort without the use of electric resistance backup heating. In comparison with a conventional air-source heat pump, the advanced-design GSHP reduced peak heating demand by more than 12 kilowatts (kW) per residence and provided energy savings. The report describes the cooling and heating season operation of the systems, including estimated seasonal efficiency, hours of operation, and load profiles for average days and peak days. The electrical energy input, cooling output, and efficiency are presented as a function of return air temperature and ground loop temperature.

  19. Study Of Heating Of The Base Region Of A Rocket

    NASA Technical Reports Server (NTRS)

    Ascoli, Edward P.; Heiba, Adel A.; Hsu, Yann-Fu; Lagnado, Ronald R.; Lynch, Edward D.; Ungewitter, Ronald J.

    1994-01-01

    Report describes theoretical study of heating in base region of proposed rocket called "NLS 1.5 stage reference vehicle." Study employed approach based on computational fluid dynamics (CFD). Involved numerical simulations of flow field in base region and in main exhaust plume of cluster of six engines with heat shields.

  20. Studies of heat source driven natural convection

    NASA Technical Reports Server (NTRS)

    Kulacki, F. A.; Nagle, M. E.; Cassen, P.

    1974-01-01

    Natural convection energy transport in a horizontal layer of internally heated fluid with a zero heat flux lower boundary, and an isothermal upper boundary, has been studied. Quantitative information on the time-mean temperature distribution and the fluctuating component of temperature about the mean temperature in steady turbulent convection are obtained from a small thermocouple inserted into the layer through the upper bounding plate. Data are also presented on the development of temperature at several vertical positions when the layer is subject to both a sudden increase and to a sudden decrease in power input. For changes of power input from zero to a value corresponding to a Rayleigh number much greater than the critical linear stability theory value, a slight hysteresis in temperature profiles near the upper boundary is observed between the heat-up and cool-down modes.

  1. [Sources of Methane in the Boreal Region

    NASA Technical Reports Server (NTRS)

    1998-01-01

    In determining the global methane budget the sources of methane must be balanced with the sinks and atmospheric inventory. The approximate contribution of the different methane sources to the budget has been establish showing the major terrestrial inputs as rice, wetlands, bogs, fens, and tundra. Measurements and modeling of production in these sources suggest that temperature, water table height and saturation along with substratum composition are important in controlling methane production and emission. The isotopic budget of 13 C and D/H in methane can be used as a tool to clarify the global budget. This approach has achieved success at constraining the inputs. Studies using the isotopic approach place constraints on global methane production from different sources. Also, the relation between the two biogenic production pathways, acetate fermentation and CO2 reduction, and the effect of substratum composition can be made using isotope measurements shows the relation between the different biogenic, thermogenic and anthropogenic sources of methane as a function of the carbon and hydrogen isotope values for each source and the atmosphere, tropospheric composition. Methane emissions from ponds and fens are a significant source in the methane budget of the boreal region. An initial study in 1993 and 1994 on the isotopic composition of this methane source and the isotopic composition in relation to oxidation of methane at the sediment surface of the ponds or fen was conducted as part of our BOREAS project. The isotopic composition of methane emitted by saturated anoxic sediment is dependent on the sediment composition and geochemistry, but will be influenced by in situ oxidation, in part, a function of rooted plant activity. The influence of oxidation mediated by rooted plant activities on the isotopic composition of methane is not well known and will depend on the plant type, sediment temperature, and numerous other variables. Information on this isotopic composition

  2. DUAL HEATED ION SOURCE STRUCTURE HAVING ARC SHIFTING MEANS

    DOEpatents

    Lawrence, E.O.

    1959-04-14

    An ion source is presented for calutrons, particularly an electrode arrangement for the ion generator of a calutron ion source. The ion source arc chamber is heated and an exit opening with thermally conductive plates defines the margins of the opening. These plates are electrically insulated from the body of the ion source and are connected to a suitable source of voltage to serve as electrodes for shaping the ion beam egressing from the arc chamber.

  3. DE 1 particle and wave observations in Auroral Kilometric Radiation (AKR) source regions

    NASA Technical Reports Server (NTRS)

    Menietti, J. D.; Burch, J. L.; Winglee, R. M.; Gurnett, D. A.

    1993-01-01

    The high-altitude plasma instrument on board the DE 1 satellite was operating during several near crossings of the AKR source in the nightside auroral region. Observations of electron distributions indicate a region of perpendicular heating adjacent to, and within, the source region. Loss cones, trapped particles, beams, and electron conical distributions are also observed near and within the source region, which extends perpendicular to the magnetic field line for at least 20 km. Near the AKR source region wave-particle interactions appear to have modified the observed electron distributions. We compare the observations to those predicted by recently published numerical simulations.

  4. Arena retrofit includes ground-source heat pump

    SciTech Connect

    Hodgson, S.F.

    1996-01-01

    The venue for Sacramento`s first professional basketball games was the {open_quotes}old Arco Arena,{close_quotes} built in 1985 just north of the downtown area and converted to offices after a large, permanent arena was constructed. In 1994, the {open_quotes}old arena{close_quotes} was acquired by a California general partnership called Del Paso Venture. To heat and cool the 3-story, 211,000-square foot structure, Del Paso has installed a ground-source heat pump system. The project is significant for the ground-source heat pump industry, because this is the first ground-source heat pump site ever designed specifically for the energy load of the building it will serve. Other projects have been calculated by rule-of-thumb. The installation and cost of the heat pump system are discussed.

  5. Interfacing primary heat sources and cycles for thermochemical hydrogen production

    SciTech Connect

    Bowman, M.G.

    1980-01-01

    Advantages cited for hydrogen production from water by coupling thermochemical cycles with primary heat include the possibility of high efficiencies. These can be realized only if the cycle approximates the criteria required to match the characteristics of the heat source. Different types of cycles may be necessary for fission reactors, for fusion reactors or for solar furnaces. Very high temperature processes based on decomposition of gaseous H/sub 2/O or CO/sub 2/ appear impractical even for projected solar technology. Cycles based on CdO decomposition are potentially quite efficient and require isothermal heat at temperatures that may be available from solar furnaces of fusion reactors. Sulfuric acid and solid sulfate cycles are potentially useful at temperatures available from each heat source. Solid sulfate cycles offer advantages for isothermal heat sources. All cycles under development include concentration and drying steps. Novel methods for improving such operations would be beneficial.

  6. Feasibility of a free-standing insertable heat source

    NASA Astrophysics Data System (ADS)

    Munger, A. C.; Mohler, J. H.; Kelly, M. D.

    The feasibility of a free-standing insertable heat source to replace an existing heat powder charge has been demonstrated. Successful development of this design eliminates the need for three laser weld joints, a high pressure interface and various manufacturing processes in the next assembly. Previous work yielded a component consisting of a stainless steel tube loaded with Fe/KC104 heat powder and a pyrotechnic ignitor. Although this design is adequate for the function, the advantages of an insertable heat source prompted the present development. The initial concept was to load a heat powder into a thin-walled container that could be inserted later. Varying air gaps prevented proper heat transmission. A freestanding thermite compact pressed to the inside contour of the stainless steel tube was then developed. This compact was attached to an ignitor which could then be threaded into the next assembly. Various thermite materials were evaluated.

  7. Thulium heat source IR D Project 91-031

    SciTech Connect

    Walter, C.E.; Kammeraad, J.E.; Newman, J.G.; Van Konynenburg, R.; VanSant, J.H.

    1991-01-01

    The goal of the Thulium Heat Source study is to determine the performance capability and evaluate the safety and environmental aspects of a thulium-170 heat source. Thulium-170 has several attractive features, including the fact that it decays to a stable, chemically innocuous isotope in a relatively short time. A longer-range goal is to attract government funding for the development, fabrication, and demonstration testing in an Autonomous Underwater Vehicle (AUV) of one or more thulium isotope power (TIP) prototype systems. The approach is to study parametrically the performance of thulium-170 heat source designs in the power range of 5-50 kW{sub th}. At least three heat source designs will be characterized in this power range to assess their performance, mass, and volume. The authors will determine shielding requirements, and consider the safety and environmental aspects of their use.

  8. Heat Transfer in Regions of Separated and Reattached Flows

    NASA Technical Reports Server (NTRS)

    Crawford, Davis H; Rumsey, Charles B

    1957-01-01

    Past experimental work has indicated that separated flow can greatly increase the heat transfer to a surface; whereas, some theoretical studies have indicated a possible decrease. Recent investigations have helped to clarify the effects of separation on heat transfer and have indicated a method of reducing separation. This paper considers the results of some of these investigations and shows the heat transfer in regions of separation and reattachment for a few specific shapes. These results show that the heat transfer in a separated region is strongly affected by the extent of separation, the location of the reattachment point, and the location of transition along the separated boundary.

  9. Melt segregation from partially molten source regions - The importance of melt density and source region size

    NASA Technical Reports Server (NTRS)

    Stolper, E.; Hager, B. H.; Walker, D.; Hays, J. F.

    1981-01-01

    An investigation is conducted regarding the changes expected in the density contrast between basic melts and peridotites with increasing pressure using the limited data available on the compressibilities of silicate melts and data on the densities of mantle minerals. It is concluded that since compressibilities of silicate melts are about an order of magnitude greater than those of mantle minerals, the density contrast between basic melts and mantle minerals must diminish significantly with increasing pressure. An earlier analysis regarding the migration of liquid in partially molten source regions conducted by Walker et al. (1978) is extended, giving particular attention to the influence of the diminished density contrast between melt and residual crystals with increasing source region depth and to the influence of source region size. This analysis leads to several generalizations concerning the factors influencing the depths at which magmas will segregate from their source regions and the degrees of partial melting that can be achieved in these source regions before melt segregation occurs.

  10. Rankine vortex evolution in a gas with heat release source

    NASA Astrophysics Data System (ADS)

    Zavershinskii, I. P.; Klimov, A. I.; Molevich, N. E.; Porfir'ev, D. P.

    2009-04-01

    The influence of a heat release source with temperature-dependent power on the stability of a Rankine vortex has been studied. A condition for the formation of a radially convergent swirling flow with increasing vorticity is found for a medium with a positive feedback between nonequilibrium heat release perturbations and the pressure at the vortex core.

  11. Pyrotechnic device provides one-shot heat source

    NASA Technical Reports Server (NTRS)

    Haller, H. C.; Lalli, V. R.

    1968-01-01

    Pyrotechnic heater provides a one-shot heat source capable of creating a predetermined temperature around sealed packages. It is composed of a blend of an active chemical element and another compound which reacts exothermically when ignited and produces fixed quantities of heat.

  12. Tests confirm gas heat as monoxide source

    SciTech Connect

    Besch, E.

    1984-03-01

    Six tests were conducted to demonstrate the potential for natural gas or oil-fired forced warm air heating equipment to produce carbon monoxide emission when the combustion process is impeded by typical causes found in households. In the case of the gas-fired units, impeded combustion produced a smell of aldehyde and various levels of carbon monoxide emission; all within the level dangerous to health. It was concluded that oil-fired warm air systems do not pose a carbon monoxide danger but that natural gas warm air systems do pose a real danger and should be so identified.

  13. Complex source description of focal regions.

    PubMed

    Monzon, Cesar; Forester, Donald W; Moore, Peter

    2006-04-01

    Closed-form solutions of the two-dimensional homogeneous wave equation are presented that provide focal-region descriptions corresponding to a converging bundle of rays. The solutions do have evanescent wave content and can be described as a source-sink pair or particle-antiparticle pair, collocated in complex space, with the complex location being critical in the determination of beam shape and focal region size. The wave solutions are not plagued by singularities, have a finite energy, and have a limitation on how small the focal size can get, with a penalty for limiting small spot sizes in the form of impractically high associated reactive energy. The electric-field-defined spot-size limiting value is 0.35lambda x 0.35lambda, which is about 38% of the Poynting-vector-defined minimum spot size (0.8lambda x 0.4lambda) and corresponds to a condition related to the maximum possible beam angle. A multiple set of solutions is introduced, and the elementary solutions are used to produce new solutions via superposition, resulting in fields with chiral character or with increased depth of focus. We do not claim generality, as the size of focal regions exhibited by the closed-form solutions has a lower bound and hence is not able to account for Pendry's "ideal lens" scenario. PMID:16604758

  14. Nuclear heat source component design considerations for HTGR process heat reactor plant concept

    SciTech Connect

    McDonald, C.F.; Kapich, D.; King, J.H.; Venkatesh, M.C.

    1982-05-01

    The coupling of a high-temperature gas-cooled reactor (HTGR) and a chemical process facility has the potential for long-term synthetic fuel production (i.e., oil, gasoline, aviation fuel, hydrogen, etc) using coal as the carbon source. Studies are in progress to exploit the high-temperature capability of an advanced HTGR variant for nuclear process heat. The process heat plant discussed in this paper has a 1170-MW(t) reactor as the heat source and the concept is based on indirect reforming, i.e., the high-temperature nuclear thermal energy is transported (via an intermediate heat exchanger (IHX)) to the externally located process plant by a secondary helium transport loop. Emphasis is placed on design considerations for the major nuclear heat source (NHS) components, and discussions are presented for the reactor core, prestressed concrete reactor vessel (PCRV), rotating machinery, and heat exchangers.

  15. Wake-induced unsteady stagnation-region heat transfer measurements

    SciTech Connect

    Magari, P.J.; LaGraff, L.E. . Dept. of Mechanical and Aerospace Engineering)

    1994-01-01

    An experimental investigation of wake-induced unsteady heat transfer in the stagnation region of a cylinder was conducted. The objective of the study was to create a quasi-steady representation of the stator/rotor interaction in a gas turbine using two stationary cylinders in crossflow. In this simulation, a larger cylinder, representing the leading-edge region of a rotor blade, was immersed in the wake of a smaller cylinder, representing the trailing-edge region of a stator vane. Time-averaged and time-resolved heat transfer results were obtained over a wide range of Reynolds number at two Mach number: one incompressible and one transonic. The tests were conducted at Reynolds numbers, Mach numbers, and gas-to-wall temperature ratios characteristic of turbine engine conditions in an isentropic compression-heated transient wind tunnel (LICH tube). The augmentation of the heat transfer in the stagnation region due to wake unsteadiness was documented by comparison with isolated cylinder tests. It was found that the time-averaged heat transfer rate at the stagnation line, expressed in terms of the Frossling number (Nu/[radical]RE), reached a maximum independent of the Reynolds number. The power spectra and cross-correlation of the heat transfer signals in the stagnation region revealed the importance of large vortical structures shed from upstream wake generator. These structures caused large positive and negative excursions about the mean heat transfer rate in the stagnation region.

  16. [Urban heat island effect based on urban heat island source and sink indices in Shenyang, Northeast China].

    PubMed

    Li, Li-Guang; Xu, Shen-Lai; Wang, Hong-Bo; Zhao, Zi-Qi; Cai, Fu; Wu, Jin-Wen; Chen, Peng-Shi; Zhang, Yu-Shu

    2013-12-01

    Based on the remote images in 2001 and 2010, the source and sink areas of urban heat island (UHI) in Shenyang City, Northeast China were determined by GIS technique. The effect of urban regional landscape pattern on UHI effect was assessed with land surface temperature (LST), area rate index (CI) of the source and sink areas and intensity index (LI) of heat island. The results indicated that the land use type changed significantly from 2001 to 2010, which significantly changed the source and sink areas of UHI, especially in the second and third circle regions. The source and sink areas were 94.3% and 5.7% in the first circle region, 64.0% and 36.0% in the third circle region in 2001, while they were 93.4% and 6.6%, 70.2% and 29.8% in 2010, respectively. It suggested that the land use pattern extended by a round shape in Shenyang led to the corresponding UHI pattern. The LST in the study area tended to decrease from the first circle region to the third. The UHI intensity was characterized with a single center in 2001 and with several centers in 2010, and the grade of UHI intensity was in a decreasing trend from 2001 to 2010. The absolute value of CI increased from the first circle region to the third, and the L1 was close to 1, suggesting the change in land use pattern had no significant influence on UHI in Shenyang. PMID:24697063

  17. Tracing meteorite source regions through asteroid spectroscopy

    NASA Astrophysics Data System (ADS)

    Thomas, Cristina Ana

    By virtue of their landing on Earth, meteorites reside in near-Earth object (NEO) orbits prior to their arrival. Thus the population of observable NEOs, in principle, gives the best representation of meteorite source bodies. By linking meteorites to NEOs, and linking NEOs to their most likely main-belt source locations, we seek to gain insight into the original solar system formation locations for different meteorite classes. To forge the first link between meteorites and NEOs, we have developed a three dimensional method for quantitative comparisons between laboratory measurements of meteorites and telescopic measurements of near-Earth objects. We utilize meteorite spectra from the Reflectance Experiment Laboratory (RELAB) database and NEO data from the SpeX instrument on the NASA Infrared Telescope Facility (IRTF). Using the Modified Gaussian Model (MGM) as a mathematical tool, we treat asteroid and meteorite spectra identically in the calculation of 1-micron and 2-micron geometric band centers and their band area ratios (BARs). Using these identical numerical parameters we quantitatively compare the spectral properties of S-, Sq-, Q- and V-type NEOs with the spectral properties of the meteorites in the H, L, LL and HED meteorite classes. For each NEO spectrum, we assign a set of probabilities for it being related to each of these meteorite classes. Our NEO- meteorite correlation probabilities are then convolved with NEO-source region probabilities to yield a final set of meteorite-source region correlations. An apparent (significant at the 2.1-sigma level) source region signature is found for the H chondrites to be preferentially delivered to the inner solar system through the 3:1 mean motion resonance. A 3:1 resonance H chondrite source region is consistent with the short cosmic ray exposure ages known for H chondrites. The spectroscopy of asteroids is subject to several sources of inherent error. The source region model used a variety of S-type spectra without

  18. Identifying the source region of plasmaspheric hiss

    NASA Astrophysics Data System (ADS)

    Laakso, Harri; Santolik, Ondrej; Horne, Richard; Kolmasová, Ivana; Escoubet, Philippe; Masson, Arnaud; Taylor, Matthew

    2015-05-01

    The presence of the plasmaspheric hiss emission around the Earth has been known for more than 50 years, but its origin has remained unknown in terms of source location and mechanism. The hiss, made of whistler mode waves, exists for most of the time in the plasmasphere and is believed to control the radiation belt surrounding the Earth which makes its understanding very important. This paper presents direct observational evidence that the plasmaspheric hiss originates in the equatorial region of the plasmaspheric drainage plumes. It shows that the emissions propagate along the magnetic field lines and away from the equator in the plumes but toward the equator at lower L shells inside the plasmasphere. The observations also suggest that the hiss waves inside the plasmasphere are absorbed as they cross the equator.

  19. Characterization of Pu-238 heat source granule containment

    SciTech Connect

    Richardson Ii, P D; Thronas, D L; Romero, J P; Sandoval, F E; Neuman, A D; Duncan, W S

    2008-01-01

    The Milliwatt Radioisotopic Thermoelectric Generator (RTG) provides power for permissive-action links. These nuclear batteries convert thermal energy to electrical energy using a doped silicon-germanium thermopile. The thermal energy is provided by a heat source made of {sup 238}Pu, in the form of {sup 238}PuO{sub 2} granules. The granules are contained in 3 layers of encapsulation. A thin T-111 liner surrounds the {sup 238}PuO{sub 2} granules and protects the second layer (strength member) from exposure to the fuel granules. The T-111 strength member contains the fuel under impact condition. An outer clad of Hastelloy-C protects the T-111 from oxygen embrittlement. The T-111 strength member is considered the critical component in this {sup 238}PuO{sub 2} containment system. Any compromise in the strength member is something that needs to be characterized. Consequently, the T-111 strength member is characterized upon it's decommissioning through Scanning Electron Microscopy (SEM), and Metallography. SEM is used in Secondary Electron mode to reveal possible grain boundary deformation and/or cracking in the region of the strength member weld. Deformation and cracking uncovered by SEM are further characterized by Metallography. Metallography sections are mounted and polished, observed using optical microscopy, then documented in the form of photomicrographs. SEM may further be used to examine polished Metallography mounts to characterize elements using the SEM mode of Energy Dispersive X-ray Spectroscopy (EDS). This paper describes the characterization of the metallurgical condition of decommissioned RTG heat sources.

  20. Analysis and performance evaluation of heat pipes with multiple heat sources

    NASA Astrophysics Data System (ADS)

    Gernert, N. J.

    1986-06-01

    A mathematical model was developed and experimentally verified for predicting the performance of cylindrical heat pipes which have multiple evaporators in series along the heat flow path, separated by finite distances. This model is an extension of the existing equations that calculate the performance of single evaporator heat pipes. The treatment of the several evaporators separated by adiabatic zones was handled by inserting the mathematical model into a user interactive heat pipe computer program. The computer model was then verified using a 1.5 meter long copper/water heat pipe system operating in the 90 to 120 C temperature range. This heat pipe was equipped with five independent evaporators. Accordingly, any combination of the five evaporators could be used to investigate multiple evaporator effects including heat flux density and heat source location.

  1. Air Source Heat Pumps for Cold Climate Applications: Recent U. S. R&D Results from IEA HPP Annex 41

    SciTech Connect

    Baxter, Van D; Groll, Dr. Eckhard A.; Shen, Bo

    2014-01-01

    Air source heat pumps are easily applied to buildings almost anywhere. They are widespread in milder climate regions but their use in cold regions is hampered due to low efficiency and heating capacity at cold outdoor temperatures. This article describes selected R&D activities aimed at improving their cold weather performance.

  2. Modeling Heat Flow for a Distributed Moving Heat Source in Micro-Laser Welding of Plastics

    NASA Astrophysics Data System (ADS)

    Grewell, David; Benatar, Avraham

    2004-06-01

    Polymer use in micro-devices, especially in the medical industry has been rapidly increasing. During assembly of micro-devices it is desirable to produce weld joints that are about 100 μm in width. This paper reviews the modeling of heat flow during through transmission infrared micro-welding of plastic using fiber coupled laser diodes. Two models were used to predict the temperature distributions within welded samples. Both models were based on a moving heat source and moving coordinate system. For the simpler model a moving point heat source was used and for the more complex model a Gaussian distributed heat source was used. It was found that the distributed model can accurately predict temperature fields in plastic laser welds for all ranges of the parameters evaluated. However, the point heat source model was only able to accurately predict temperature fields with a relatively small laser focal spot (25 μm). In addition it was found that for micro-welding of plastics, when the dimensionless distribution parameter is less than two, a point heat source model predicts similar widths to those predicted by a distributed heat source model.

  3. Mini-Brayton heat source assembly design study. Volume 2: Titan 3C mission. [minimum weight modifications

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Major conclusions of the space shuttle heat source assembly study are reported that project a minimum weight design for a Titan 3 C synchronous orbit mission; requirements to recover the heat source in orbit are eliminated. This concept permits location of the heat source end enclosure supports and heat source assembly support housing in a low temperature region external to the insulation enclosure and considers titanium and beryllium alloys for these support elements. A high melting insulation blanket consisting of nickel foil coated with zirconia, or of gold foil separated with glass fiber layers, is selected to provide emergency cooling in the range 2000 to 2700 F to prevent the isotope heat source from reaching unsafe temperatures. A graphic view of the baseline heat source assembly is included.

  4. Alpha particle heating at comet-solar wind interaction regions

    NASA Technical Reports Server (NTRS)

    Sharma, A. S.; Papadopoulos, K.

    1995-01-01

    The satellite observations at comet Halley have shown strong heating of solar wind alpha particles over an extended region dominated by high-intensity, low-frequency turbulence. These waves are excited by the water group pickup ions and can energize the solar wind plasma by different heating processes. The alpha particle heating by the Landau damping of kinetic Alfven waves and the transit time damping of low-frequency hydromagnetic waves in this region of high plasma beta are studied in this paper. The Alfven wave heating was shown to be the dominant mechanism for the observed proton heating, but it is found to be insufficient to account for the observed alpha particle heating. The transit time damping due to the interaction of the ions with the electric fields associated with the magnetic field compressions of magnetohydrodynamic waves is found to heat the alpha particles preferentially over the protons. Comparison of the calculated heating times for the transit time damping with the observations from comet Halley shows good agreement. These processes contribute to the thermalization of the solar wind by the conversion of its directed energy into the thermal energy in the transition region at comet-solar wind interaction.

  5. Ground source heat pumps (GSHP) for heating and cooling in Greece

    NASA Astrophysics Data System (ADS)

    Dimera, Nikoletta

    This report presents the results of a theoretical study about the feasibility of closed loop Ground Source Heat Pumps (GSHP) for heating and cooling in Greece in terms of their impact on the capital and running costs of the building services systems of the buildings. The main aim of carrying out this study was to investigate if the heating and cooling potential of the ground could be utilized cost efficiently to serve the buildings energy demand in the Greek region. At first, an existing implementation of a closed loop GSHP system in Greece is presented and its efficiency is discussed. The aim of doing so was to understand the way of sizing such systems and the efficiency of this technology in Greek climatic and ground conditions. In a separate part of this report, the impact of different user behaviour and of various ways of sizing a GSHP system is investigated in terms of the cost impact of the examined different options as well as of their effect on the internal health and comfort conditions. After the building simulation under different scenarios, it was concluded that the user behavior - the operation of windows mostly - can result in great savings on the annual energy bills. The conclusions of this first part of the report about the user behaviour and the way of sizing GSHP systems were utilized in the next part of it, where a GSHP system is proposed for a building currently under construction in central Greece. A simple 30-year cost analysis was used in order to estimate the performance of the proposed GSHP system in economic terms and to compare it with the conventional HVAC system commonly used in Greece. According to the results of the analysis, the capital cost of installing a GSHP system for heating and cooling in buildings in Greece appears higher than the cost of conventional HVAC systems. More specifically, the capital cost of an installation for heating including gas boilers and a cooling system based on air conditioning split units is about the

  6. Heating of active region cores: Impulsive or steady?

    NASA Astrophysics Data System (ADS)

    Tripathi, Durgesh

    The question of active region heating has proven to be highly challenging since its discovery in 1940s. The recent observational facilities have shed new lights towards the understanding of this problem. In this paper we review some of the new measurements to study the heating mechanisms in the hot core loops of active regions using the observations recorded by Solar Ultraviolet Measurements of Emitted Radiation (SUMER) onboard SoHO and the Extreme-ultraviolet Imaging Spectrometer (EIS) aboard Hinode. These new measurements show that the properties of hot core loops are consistent with by impulsive heating -- low frequency nanoflare - scenario. However, the evidences are not strong enough to rule-out steady heating completely. Further measurement using better spectral resolution and temperature coverage is required, which will be provided by Interface Region Imaging Spectrometer (IRIS) and Solar-C in near future.

  7. Life cycle assessment of base-load heat sources for district heating system options

    SciTech Connect

    Ghafghazi, Saeed; Sowlati, T.; Sokhansanj, Shahabaddine; Melin, Staffan

    2011-03-01

    Purpose There has been an increased interest in utilizing renewable energy sources in district heating systems. District heating systems are centralized systems that provide heat for residential and commercial buildings in a community. While various renewable and conventional energy sources can be used in such systems, many stakeholders are interested in choosing the feasible option with the least environmental impacts. This paper evaluates and compares environmental burdens of alternative energy source options for the base load of a district heating center in Vancouver, British Columbia (BC) using the life cycle assessment method. The considered energy sources include natural gas, wood pellet, sewer heat, and ground heat. Methods The life cycle stages considered in the LCA model cover all stages from fuel production, fuel transmission/transportation, construction, operation, and finally demolition of the district heating system. The impact categories were analyzed based on the IMPACT 2002+ method. Results and discussion On a life-cycle basis, the global warming effect of renewable energy options were at least 200 kgeqCO2 less than that of the natural gas option per MWh of heat produced by the base load system. It was concluded that less than 25% of the upstream global warming impact associated with the wood pellet energy source option was due to transportation activities and about 50% of that was resulted from wood pellet production processes. In comparison with other energy options, the wood pellets option has higher impacts on respiratory of inorganics, terrestrial ecotoxicity, acidification, and nutrification categories. Among renewable options, the global warming impact of heat pump options in the studied case in Vancouver, BC, were lower than the wood pellet option due to BC's low carbon electricity generation profile. Ozone layer depletion and mineral extraction were the highest for the heat pump options due to extensive construction required for these

  8. Diffusion of Heat from a Line Source in Isotropic Turbulence

    NASA Technical Reports Server (NTRS)

    Uberoi, Mahinder S; Corrsin, Stanley

    1953-01-01

    An experimental and analytical study has been made of some features of the turbulent heat diffusion behind a line heated wire stretched perpendicular to a flowing isotropic turbulence. The mean temperature distributions have been measured with systematic variations in wind speed, size of turbulence-producing grid, and downstream location of heat source. The nature of the temperature fluctuation field has been studied. A comparison of Lagrangian and Eulerian analyses for diffusion in a nondecaying turbulence yields an expression for turbulent-heat-transfer coefficient in terms of turbulence velocity and a Lagrangian "scale." the ratio of Eulerian to Lagrangian microscale has been determined theoretically by generalization of a result of Heisenberg and with arbitrary constants taken from independent sources, shows rough agreement with experimental results. A convenient form has been deduced for the criterion of interchangeability of instantaneous space and time derivatives in a flowing turbulence.

  9. Assessment of dynamic energy conversion systems for radioisotope heat sources

    SciTech Connect

    Thayer, G.R.; Mangeng, C.A.

    1985-06-01

    The use of dynamic conversion systems to convert the heat generated in a 7500 W(t) 90 Sr radioisotopic heat source to electricity is examined. The systems studies were Stirling; Brayton Cycle; three organic Rankines (ORCs) (Barber-Nichols/ORMAT, Sundstrand, and TRW); and an organic Rankine plus thermoelectrics. The systems were ranked for a North Warning System mission using a Los Alamos Multiattribute Decision Theory code. Three different heat source designs were used: case I with a beginning of life (BOL) source temperature of 640 C, case II with a BOL source temperature of 745/sup 0/C, and case III with a BOL source temperature of 945/sup 0/C. The Stirling engine system was the top-ranked system of cases I and II, closely followed by the ORC systems in case I and ORC plus thermoelectrics in case II. The Brayton cycle system was top-ranked for case III, with the Stirling engine system a close second. The use of /sup 238/Pu in heat source sizes of 7500 W(t) was examined and found to be questionable because of cost and material availability and because of additional requirements for analysis of safeguards and critical mass.

  10. Assessment of dynamic energy conversion systems for radioisotope heat sources

    NASA Astrophysics Data System (ADS)

    Thayer, G. R.; Mangeng, C. A.

    1985-06-01

    The use of dynamic conversion systems to convert the heat generated in a 7500 W(t) 90 Sr radioisotopic heat source to electricity is examined. The systems studies were: Stirling; Brayton cycle; three organic Rankines (ORCs) (Barber-Nichols/ORMAT, Sundstrand, and TRW); and an organic Rankine plus thermoelectrics. The systems were ranked for a North Warning System mission using a Los Alamos multiattribute decision theory code. Three different heat source designs were used: case 1 with a beginning of life (BOL) source temperature of 640 C, case 2 with a BOL source temperature of 745 C, and case 3 with a BOL source temperature of 945 C. The Stirling engine system was the top-ranked system of case 1 and 2, closely followed by the ORC systems in case 1 and ORC plus thermoelectrics in case 2. The Brayton cycle system was top-ranked for case 3, with the Stirling engine system a close second. The use of (238) Pu in heat source sizes of 7500 W(t) is examined and it is found to be questionable because of cost and material availability and because of additional requirements for anlaysis of safeguards and critical mass.

  11. Lunar heat flow: Regional prospective of the Apollo landing sites

    NASA Astrophysics Data System (ADS)

    Siegler, M. A.; Smrekar, S. E.

    2014-01-01

    reexamine the Apollo Heat Flow Experiment in light of new orbital data. Using three-dimensional thermal conduction models, we examine effects of crustal thickness, density, and radiogenic abundance on measured heat flow values at the Apollo 15 and 17 sites. These models show the importance of regional context on heat flux measurements. We find that measured heat flux can be greatly altered by deep subsurface radiogenic content and crustal density. However, total crustal thickness and the presence of a near-surface radiogenic-rich ejecta provide less leverage, representing only minor (<1.5 mW m-2) perturbations on surface heat flux. Using models of the crust implied by Gravity Recovery and Interior Laboratory results, we found that a roughly 9-13 mW m-2 mantle heat flux best approximate the observed heat flux. This equates to a total mantle heat production of 2.8-4.1 × 1011 W. These heat flow values could imply that the lunar interior is slightly less radiogenic than the Earth's mantle, perhaps implying that a considerable fraction of terrestrial mantle material was incorporated at the time of formation. These results may also imply that heat flux at the crust-mantle boundary beneath the Procellarum potassium, rare earth element, and phosphorus (KREEP) Terrane (PKT) is anomalously elevated compared to the rest of the Moon. These results also suggest that a limited KREEP-rich layer exists beneath the PKT crust. If a subcrustal KREEP-rich layer extends below the Apollo 17 landing site, required mantle heat flux can drop to roughly 7 mW m-2, underlining the need for future heat flux measurements outside of the radiogenic-rich PKT region.

  12. TRMM observations of latent heat distribution over the Indian summer monsoon region and associated dynamics

    NASA Astrophysics Data System (ADS)

    Subrahmanyam, Kandula V.; Kishore Kumar, Karanam

    2016-05-01

    The latent heat released/absorbed in the Earth's atmosphere due to phase change of water molecule plays a vital role in various atmospheric processes. It is now well established that the latent heat released in the clouds is the secondary source of energy for driving the atmosphere, the Sun being the primary. In this context, studies on latent heat released in the atmosphere become important to understand the some of the physical processes taking place in the atmosphere. One of the important implications of latent heat release is its role in driving the circulations on various temporal and spatial scales. Realizing the importance of latent heat released in the clouds, a comprehensive study is carried out to understand its role in driving the mesoscale circulation. As Indian summer monsoon (ISM) serves as natural laboratory for studying the clouds and their microphysics, an attempt is made to explore the latent heat distribution over this region using 13 years of Tropical Rainfall Measuring Mission (TRMM) observations. The observed profiles of latent heating over ISM region showed large spatial and temporal variability in the magnitude thus reflecting the presence of organization of convection on mesoscale. The latent profiles in convective and stratiform regions are segregated to study the differences in their interaction with large-scale environment. Various re-analysis dataset were used to examine the role of latent heating distribution on the mesoscale circulation. The significance of the present study lies in establishing the vertical distribution of latent heating and their impact on the background circulation.

  13. DE 1 particle and wave observations in auroral kilometric radiation (AKR) source regions

    SciTech Connect

    Menietti, J.D.; Burch, J.L. ); Winglee, R.M. ); Gurnett, D.A. )

    1993-04-01

    The authors report on data collected by the DE 1 satellite on several near crossings of the auroral kilometric radiation (AKR) source in the nightside auroral region. Plasma instruments aboard the high altitude satellite observed regions with strong perpendicular heating (T[sub [perpendicular

  14. TEM Pump With External Heat Source And Sink

    NASA Technical Reports Server (NTRS)

    Nesmith, Bill J.

    1991-01-01

    Proposed thermoelectric/electromagnetic (TEM) pump driven by external source of heat and by two or more heat pipe radiator heat sink(s). Thermoelectrics generate electrical current to circulate liquid metal in secondary loop of two-fluid-loop system. Intended for use with space and terrestrial dual loop liquid metal nuclear reactors. Applications include spacecraft on long missions or terrestrial beacons or scientific instruments having to operate in remote areas for long times. Design modified to include multiple radiators, converters, and ducts, as dictated by particular application.

  15. Fluid dynamics at transition regions of enhanced heat transfer channels

    NASA Astrophysics Data System (ADS)

    Case, Jennifer C.; Pohlman, Nicholas A.

    2012-11-01

    Helical wire coil inserts are used to enhance heat transfer in high heat flux cooling channels. Past research using temperature probes has sufficiently proven that wire coils increase heat transfer by factors of three to five through the disruption of the boundary layer in the channels. The coils are passive devices that are inexpensive to manufacture and easily integrate into existing heat exchangers given the limited pressure drop they produce. Most of the fluid mechanics research in flow over helical coils has focused on the dynamics and vortex structure in fully developed regions rather than the short transition region where the enhanced heat transfer is often expected. Understanding how the development of the flow occurs over the axial length of the cooling channel will determine minimum dimensions necessary for enhanced heat transfer. Results of particle-shadow velocimetry (PSV) measurements report on the flow velocities and turbulence that occurs in the transition regions at the beginning of wire coil inserts. The ability to relate parameters such as flow rate, wire diameter, coil pitch, and the total tube length will increase fundamental knowledge and will allow for more efficient heat exchanger designs. Funding provided by NIU's Undergraduate Special Opportunities in Artistry & Research grant program.

  16. Stagnation region heat transfer augmentation at very high turbulence levels

    DOE PAGESBeta

    Kingery, Joseph E.; Ames, Forrest E.

    2016-08-01

    Current land-based gas turbines are growing in size producing higher approach flow Reynolds numbers at the leading edge of turbine nozzles. These vanes are subjected to high intensity large scale turbulence. This present paper reports on the research which significantly expands the parameter range for stagnation region heat transfer augmenta-tion due to high intensity turbulence. Heat transfer measurements were acquired over two constant heat flux test surfaces with large diameter leading edges (10.16 cm and 40.64 cm). The test surfaces were placed downstream from a new high intensity (17.4%) mock combustor and tested over an eight to one range inmore » approach flow Reynolds number for each test surface. Stagnation region heat transfer augmentation for the smaller (ReD = 15,625–125,000) and larger (ReD = 62,500–500,000) leading edge regions ranged from 45% to 81% and 80% to 136%, respectively. Furthermore, these data also include heat transfer distributions over the full test surface compared with the earlier data acquired at six additional inlet turbulence conditions. These surfaces exhibit continued but more moderate acceleration downstream from the stagnation regions and these data are expected to be useful in testing bypass transition predictive approaches. This database will be useful to gas turbine heat transfer design engineers. [DOI: 10.1115/1.4032677]« less

  17. Step - wise transient method - Influence of heat source inertia

    NASA Astrophysics Data System (ADS)

    Malinarič, Svetozár; Dieška, Peter

    2016-07-01

    Step-wise transient (SWT) method is an experimental technique for measuring the thermal diffusivity and conductivity of materials. Theoretical models and experimental apparatus are presented and the influence of the heat source capacity are investigated using the experiment simulation. The specimens from low density polyethylene (LDPE) were measured yielding the thermal diffusivity 0.165 mm2/s and thermal conductivity 0.351 W/mK with the coefficient of variation less than 1.4 %. The heat source capacity caused the systematic error of the results smaller than 1 %.

  18. Characterization of Pu-238 Heat Source Granule Containment

    SciTech Connect

    Richardson, Paul Dean II; Sanchez, Joey Leo; Wall, Angelique Dinorah; Chavarria, Rene

    2015-02-11

    The Milliwatt Radioisotopic Themoelectric Generator (RTG) provides power for permissive-action links. Essentially these are nuclear batteries that convert thermal energy to electrical energy using a doped silicon-germanium thermopile. The thermal energy is provided by a heat source made of 238Pu, in the form of 238PuO2 granules. The granules are contained by 3 layers of encapsulation. A thin T-111 liner surrounds the 238PuO2 granules and protects the second layer (strength member) from exposure to the fuel granules. An outer layer of Hastalloy-C protects the T-111 from oxygen embrittlement. The T-111 strength member is considered the critical component in this 238PuO2 containment system. Any compromise in the strength member seen during destructive testing required by the RTG surveillance program is characterized. The T-111 strength member is characterized through Scanning Electron Microscopy (SEM), and Metallography. SEM is used in the Secondary Electron mode to reveal possible grain boundary deformation and/or cracking in the region of the strength member weld. Deformation and cracking uncovered by SEM are further characterized by Metallography. Metallography sections are mounted and polished, observed using optical microscopy, then documented in the form of microphotographs. SEM mat further be used to examine polished Metallography mounts to characterize elements using the SEM mode of Energy Dispersive X-ray spectroscopy (EDS).

  19. Prandtl Number Dependent Natural Convection with Internal Heat Sources

    SciTech Connect

    Kang Hee Lee; Seung Dong Lee; Kune Y. Suh; Joy L. Rempe; Fan-Bill Cheung; Sang B. Kim

    2004-06-01

    Natural convection plays an important role in determining the thermal load from debris accumulated in the reactor vessel lower head during a severe accident. Recently, attention is being paid to the feasibility of external vessel flooding as a severe accident management strategy and to the phenomena affecting the success path for retaining the molten core material inside the vessel. The heat transfer inside the molten core material can be characterized by the strong buoyancy-induced flows resulting from internal heating due to decay of fission products. The thermo-fluid dynamic characteristics of such flow depend strongly on the thermal boundary conditions. The spatial and temporal variation of heat flux on the pool wall boundaries and the pool superheat are mainly characterized by the natural convection flow inside the molten pool. In general, the natural convection heat transfer phenomena involving the internal heat generation are represented by the modified Rayleigh number (Ra’), which quantifies the internal heat source and hence the strength of the buoyancy force. In this study, tests were conducted in a rectangular section 250 mm high, 500 mm long and 160 mm wide. Twenty-four T-type thermocouples were installed in the test section to measure temperatures. Four T-type thermocouples were used to measure the boundary temperatures. The thermocouples were placed in designated locations after calibration. A direct heating method was adopted in this test to simulate the uniform heat generation. The experiments covered a range of Ra' between 1.5x106 and 7.42x1015 and the Prandtl number (Pr) between 0.7 and 6.5. Tests were conducted with water and air as simulant. The upper and lower boundary conditions were maintained uniform. The results demonstrated feasibility of the direct heating method to simulate uniform volumetric heat generation. Particular attentions were paid to the effect of Pr on natural convection heat transfer within the rectangular pool.

  20. The identification of source regions of black carbon at a receptor site off the eastern coast of China

    NASA Astrophysics Data System (ADS)

    Guo, Qingfeng; Hu, Min; Guo, Song; Wu, Zhijun; Hu, Weiwei; Peng, Jianfei; Hu, Wei; Wu, Yusheng; Yuan, Bin; Zhang, Qiang; Song, Yu

    2015-01-01

    The black carbon (BC) mass concentration and the particle chemical compositions were continually measured at Changdao Island, which is a regional receptor site off the eastern coast of China. This island is in the transport passage of the continental outflow to the Pacific Ocean when the East Asia monsoon prevails in the winter and spring. The campaign period was for March and April 2011, which corresponded to heating and non-heating periods in northern China. The effect of BC emission source regions on BC measured at Changdao Island between the heating and non-heating periods was determined by integrating the total potential source contribution function (TPSCF) model with the new monthly emission inventory in 2010 and the fire counts retrieved from MODIS during the campaign. BC concentrations were determined to be highest for similar times of day for both the heating and non-heating periods: 4.27 μg m-3 at 8:00 AM and 3.06 μg m-3 at 9:00 AM, respectively. The probable source regions for BC were primarily located in Shandong and Jiangsu provinces (and in other neighboring provinces) for both periods. However, the source regions for the non-heating period extended more to the north and southwest than those of the heating period. TPSCF values were correlated with the emission rates from residential, industry, transportation, and power plants sources in the anthropogenic emission inventory. This correlation provides an indirect and qualitative process to verify the emission inventory. In the heating period, the predominant source was the residential source in the emission inventory, and this source had a significant effect on the BC concentration. The differing peak concentrations between the two periods may be observed because of the increased residential heating during the heating period, which suggested that the measures employed by the government and environmental managers to reduce the emissions of pollutants should be stricter in the identified source regions

  1. RF Heating in Electron Cyclotron Resonance Ion Sources

    NASA Astrophysics Data System (ADS)

    Mascali, D.; Gammino, S.; Celona, L.; Ciavola, G.

    2011-12-01

    ECRIS—Electron Cyclotron Resonance Ion Sources are able to feed accelerators with intense currents of highly charged ions. In ECRIS a high density—high temperature plasma is generated by means of the Electron Cyclotron Resonance Heating inside a B-min, MHD stable trap. The state of the art about the principal heating mechanisms will be given. The paper will specially discuss the most critical and still open issues concerning the influence of the magnetic field and of the RF frequency on the plasma heating, as well as the impact of possible non-linear pumping wave—to—plasma interactions. The contribution of INFN-LNS will be specifically underlined. A short review on the future perspectives for the design of new generation ion sources will be given in conclusion.

  2. Role of Internal Heat Source for Eruptive Plumes on Triton

    NASA Technical Reports Server (NTRS)

    Duxbury, N. S.; Brown, R. H.

    1996-01-01

    For the first time the role of the internal heat source, due to radioactive decay in Triton's core, is investigate with respect to geyser-like plumes...A new mechanism of energy supply to the Tritonian eruptive plumes is proposed...We present the critical values of these parameters for Triton. A possible origin of the subsurface vents on Triton is also suggested.

  3. Spallation neutron source cryomodule heat loads and thermal design

    SciTech Connect

    E. F. Daly; V. Ganni; C. H. Rode; W. J. Schneider; K. M. Wilson; M. A. Wiseman

    2002-05-10

    When complete, the Spallation Neutron Source (SNS) will provide a 1 GeV, 2 MW beam for experiments. One portion of the machine's linac consists of over 80 Superconducting Radio Frequency (SRF) 805 MHz cavities housed in a minimum of 23 cryomodules operating at a saturation temperature of 2.1 K. Minimization of the total heat load is critical to machine performance and for efficient operation of the system. The total heat load of the cryomodules consists of the fixed static load and the dynamic load, which is proportional to the cavity performance. The helium refrigerator supports mainly the cryomodule loads and to a lesser extent the distribution system loads. The estimated heat loads and calculated thermal performance are discussed along with two unique features of this design: the helium heat exchanger housed in the cryomodule return end can and the helium gas cooled fundamental power coupler.

  4. Titanium-boron mixtures as variable heat sources

    SciTech Connect

    Begeal, D.R. ); Munger, A.C. )

    1990-01-01

    The reaction between titanium and boron to form titanium diboride is one of the hottest pyrotechnic reactions in common usage and offers the advantage of being a solid state gasless reaction. Based on the work of Hart, a heat source with a variable output has been developed that utilizes this pyrotechnic. The device was designed to deliver the heat across a 0.26 inch inner diameter hemispherical bulkhead of a material and thickness that can be specified by the user. For evaluation purposes, the bulkhead was 0.036 inches thick stainless steel. The maximum temperature on the tip of the bulkhead was 950{degree}C for the pure reactants and 680{degree}C for blends diluted with 30 weight percent of alumina. Further, the temperature was uniform within {plus minus}20{degree}C across a 2 millimeter diameter on the tip of the bulkhead, and the temperature rise characteristics were repeatable. Ignition of the titanium/boron heat powder was accomplished by first igniting an adjacent charge of titanium subhydride/potassium perchlorate with a one ohm bridge wire. The header was constructed of inconel, a glass ceramic insulator, and hastelloy pins. The ignition and subsequent burn of the titanium/boron was nearly instantaneous, thus the thermal output was dependent only on the heat transfer properties of the materials and geometry involved. Therefore, the user can tailor the blend dilution and the bulkhead characteristics to provide a large range of precise heat outputs. Typical uses of this heat source include timely ignition of other materials, or heating confined gas to perform useful mechanical work. Achievement of the precise heat output required special attention to the purity of the titanium and boron and to the blending process. These aspects, as well as those described above will be described. 6 refs., 9 figs., 3 tabs.

  5. Effectiveness of an ammonia-water mixture turbine system to hot water heat source

    SciTech Connect

    Suzuki, Takashi; Noguchi, Hideki; Amano, Yoshiharu; Hashizume, Takumi; Akiba, Masashi; Tanzawa, Yoshiaki; Usui, Akira

    1999-07-01

    An ammonia-water mixture (AWM) turbine system is proposed in the paper. The authors call this Waseda ammonia-water Mixture Turbine System (W-MTS). The paper presents some results of the investigation for design of a bottoming cycle that is supplied steam as heat source. The results of the cycle simulation show that the W-MTS is superior to the other simple Kalina cycles (KCS1 and KCS34) to pressurized hot water and steam as a latent and a sensible heat source at a temperature of 160 C. The main components of the W-MTS are a heat recovery vapor generator, two condensers, an AWM turbine and two separators. The W-MTS features two simple Kalina cycles, KCS-1 and KCS-34. The W-MTS behaves like KCS-1 at low ammonia mass fraction region, and like KCS-34 at high ammonia mass fraction region. The W-MTS shows the higher output power rather than the two simple Kalina cycles at all over the ammonia mass fraction. The W-MTS is expected to be effective with the heat recovery of two preheaters in a AWM-vapor generation not only to sensible heat sources, such as exhaust gas that comes from gas turbine, hot water from a waste heat recovery system, etc., but also latent heat source e.g. steam. The results of the simulation show that the ammonia mass fraction at the inlet of the heat recovery vapor generator, turbine inlet pressure and temperature in the separator are the key parameters for optimizing the operating conditions of the cycles. In the temperature rage between 120 C and 200 C, the W-MTS generates more power rather than two simple Kaline cycles.

  6. Stagnation Region Heat Transfer Augmentation at Very High Turbulence Levels

    SciTech Connect

    Ames, Forrest; Kingery, Joseph E.

    2015-06-17

    A database for stagnation region heat transfer has been extended to include heat transfer measurements acquired downstream from a new high intensity turbulence generator. This work was motivated by gas turbine industry heat transfer designers who deal with heat transfer environments with increasing Reynolds numbers and very high turbulence levels. The new mock aero-combustor turbulence generator produces turbulence levels which average 17.4%, which is 37% higher than the older turbulence generator. The increased level of turbulence is caused by the reduced contraction ratio from the liner to the exit. Heat transfer measurements were acquired on two large cylindrical leading edge test surfaces having a four to one range in leading edge diameter (40.64 cm and 10.16 cm). Gandvarapu and Ames [1] previously acquired heat transfer measurements for six turbulence conditions including three grid conditions, two lower turbulence aero-combustor conditions, and a low turbulence condition. The data are documented and tabulated for an eight to one range in Reynolds numbers for each test surface with Reynolds numbers ranging from 62,500 to 500,000 for the large leading edge and 15,625 to 125,000 for the smaller leading edge. The data show augmentation levels of up to 136% in the stagnation region for the large leading edge. This heat transfer rate is an increase over the previous aero-combustor turbulence generator which had augmentation levels up to 110%. Note, the rate of increase in heat transfer augmentation decreases for the large cylindrical leading edge inferring only a limited level of turbulence intensification in the stagnation region. The smaller cylindrical leading edge shows more consistency with earlier stagnation region heat transfer results correlated on the TRL (Turbulence, Reynolds number, Length scale) parameter. The downstream regions of both test surfaces continue to accelerate the flow but at a much lower rate than the leading edge. Bypass transition occurs

  7. Coupled Groundwater and Heat Flow in the Tahoe Basin Region

    NASA Astrophysics Data System (ADS)

    Trask, J. C.

    2002-12-01

    We propose that recent developments in available temperature probe technology and improvements in appropriate modeling software, together with the advent of desktop high-speed computing, have enabled the thermal analysis approach to be an inexpensive, robust, and practical way to constrain groundwater flow fields in a wide variety of environments. We present field measurements and numerical models of coupled heat and groundwater flow in the Tahoe Basin region. In montane regions such as the Tahoe Basin, steep topography provides a driving force for deep groundwater flow. Deep groundwater flow re-routes subsurface heat flow, impacting temperature gradients to depth, including the shallow subsurface (<100m depth). In the Tahoe Basin region, the magnitude of deep groundwater flow on the areal or regional scale has been largely unknown. We present examples of borehole temperature profiles that constrain possible areal groundwater flow patterns, including the magnitude of flow beneath the bottom of boreholes probed.

  8. Ground Source Heat Pump Sub-Slab Heat Exchange Loop Performance in a Cold Climate

    SciTech Connect

    Mittereder, N.; Poerschke, A.

    2013-11-01

    This report presents a cold-climate project that examines an alternative approach to ground source heat pump (GSHP) ground loop design. The innovative ground loop design is an attempt to reduce the installed cost of the ground loop heat exchange portion of the system by containing the entire ground loop within the excavated location beneath the basement slab. Prior to the installation and operation of the sub-slab heat exchanger, energy modeling using TRNSYS software and concurrent design efforts were performed to determine the size and orientation of the system. One key parameter in the design is the installation of the GSHP in a low-load home, which considerably reduces the needed capacity of the ground loop heat exchanger. This report analyzes data from two cooling seasons and one heating season. Upon completion of the monitoring phase, measurements revealed that the initial TRNSYS simulated horizontal sub-slab ground loop heat exchanger fluid temperatures and heat transfer rates differed from the measured values. To determine the cause of this discrepancy, an updated model was developed utilizing a new TRNSYS subroutine for simulating sub-slab heat exchangers. Measurements of fluid temperature, soil temperature, and heat transfer were used to validate the updated model.

  9. Self-Heating Effects In Polysilicon Source Gated Transistors

    PubMed Central

    Sporea, R. A.; Burridge, T.; Silva, S. R. P.

    2015-01-01

    Source-gated transistors (SGTs) are thin-film devices which rely on a potential barrier at the source to achieve high gain, tolerance to fabrication variability, and low series voltage drop, relevant to a multitude of energy-efficient, large-area, cost effective applications. The current through the reverse-biased source barrier has a potentially high positive temperature coefficient, which may lead to undesirable thermal runaway effects and even device failure through self-heating. Using numerical simulations we show that, even in highly thermally-confined scenarios and at high current levels, self-heating is insufficient to compromise device integrity. Performance is minimally affected through a modest increase in output conductance, which may limit the maximum attainable gain. Measurements on polysilicon devices confirm the simulated results, with even smaller penalties in performance, largely due to improved heat dissipation through metal contacts. We conclude that SGTs can be reliably used for high gain, power efficient analog and digital circuits without significant performance impact due to self-heating. This further demonstrates the robustness of SGTs. PMID:26351099

  10. Self-Heating Effects In Polysilicon Source Gated Transistors.

    PubMed

    Sporea, R A; Burridge, T; Silva, S R P

    2015-01-01

    Source-gated transistors (SGTs) are thin-film devices which rely on a potential barrier at the source to achieve high gain, tolerance to fabrication variability, and low series voltage drop, relevant to a multitude of energy-efficient, large-area, cost effective applications. The current through the reverse-biased source barrier has a potentially high positive temperature coefficient, which may lead to undesirable thermal runaway effects and even device failure through self-heating. Using numerical simulations we show that, even in highly thermally-confined scenarios and at high current levels, self-heating is insufficient to compromise device integrity. Performance is minimally affected through a modest increase in output conductance, which may limit the maximum attainable gain. Measurements on polysilicon devices confirm the simulated results, with even smaller penalties in performance, largely due to improved heat dissipation through metal contacts. We conclude that SGTs can be reliably used for high gain, power efficient analog and digital circuits without significant performance impact due to self-heating. This further demonstrates the robustness of SGTs. PMID:26351099

  11. Self-Heating Effects In Polysilicon Source Gated Transistors

    NASA Astrophysics Data System (ADS)

    Sporea, R. A.; Burridge, T.; Silva, S. R. P.

    2015-09-01

    Source-gated transistors (SGTs) are thin-film devices which rely on a potential barrier at the source to achieve high gain, tolerance to fabrication variability, and low series voltage drop, relevant to a multitude of energy-efficient, large-area, cost effective applications. The current through the reverse-biased source barrier has a potentially high positive temperature coefficient, which may lead to undesirable thermal runaway effects and even device failure through self-heating. Using numerical simulations we show that, even in highly thermally-confined scenarios and at high current levels, self-heating is insufficient to compromise device integrity. Performance is minimally affected through a modest increase in output conductance, which may limit the maximum attainable gain. Measurements on polysilicon devices confirm the simulated results, with even smaller penalties in performance, largely due to improved heat dissipation through metal contacts. We conclude that SGTs can be reliably used for high gain, power efficient analog and digital circuits without significant performance impact due to self-heating. This further demonstrates the robustness of SGTs.

  12. Ground Source Heat Pump Sub-Slab Heat Exchange Loop Performance in a Cold Climate

    SciTech Connect

    Mittereder, Nick; Poerschke, Andrew

    2013-11-01

    This report presents a cold-climate project that examines an alternative approach to ground source heat pump (GSHP) ground loop design. The innovative ground loop design is an attempt to reduce the installed cost of the ground loop heat exchange portion of the system by containing the entire ground loop within the excavated location beneath the basement slab. Prior to the installation and operation of the sub-slab heat exchanger, energy modeling using TRNSYS software and concurrent design efforts were performed to determine the size and orientation of the system. One key parameter in the design is the installation of the GSHP in a low-load home, which considerably reduces the needed capacity of the ground loop heat exchanger. This report analyzes data from two cooling seasons and one heating season.

  13. The rotating heat pipe - Implementation as a uniform-temperature heat source

    NASA Astrophysics Data System (ADS)

    Limoges, R. F.

    1981-11-01

    A wickless rotating heat pipe, if properly controlled, is a uniform heat source. The data presented are based on work done with 12.7 cm diameter x 76 cm long rotating heat pipes operating between 120 and 140 C. The major areas reviewed are: materials of fabrication, working fluids, sealing, temperature control, heaters, and safety. The optimum rotating heat pipe defined by these studies is fabricated of type 304 stainless steel, uses water as the working fluid, is sealed with welded joints, and utilizes a pressure switch and a fast-response quartz lamp for temperature control. Surface-temperature control of + or - 0.15 C and temperature uniformity within 0.8 C are obtained. Results of experiments designed to study the effects of hydrogen in the enclosed volume of the heat pipe are presented.

  14. Estimation of human heat loss in five Mediterranean regions.

    PubMed

    Bilgili, M; Simsek, E; Sahin, B; Yasar, A; Ozbek, A

    2015-10-01

    This study investigates the effects of seasonal weather differences on the human body's heat losses in the Mediterranean region of Turkey. The provinces of Adana, Antakya, Osmaniye, Mersin and Antalya were chosen for the research, and monthly atmospheric temperatures, relative humidity, wind speed and atmospheric pressure data from 2007 were used. In all these provinces, radiative, convective and evaporative heat losses from the human body based on skin surface and respiration were analyzed from meteorological data by using the heat balance equation. According to the results, the rate of radiative, convective and evaporative heat losses from the human body varies considerably from season to season. In all the provinces, 90% of heat loss was caused by heat transfer from the skin, with the remaining 10% taking place through respiration. Furthermore, radiative and convective heat loss through the skin reached the highest values in the winter months at approximately between 110 and 140W/m(2), with the lowest values coming in the summer months at roughly 30-50W/m(2). PMID:26025784

  15. 60-watt isotopic heat source for terrestrial applications

    SciTech Connect

    Brittain, W.M.

    1995-01-20

    A sealed isotopic heat source (IHS) with a nominal thermal inventory of 60 watts is being developed by the U.S. Department of Energy (DOE) for use in remote terrestrial applications that require isotopic power for electrical power generation. Emphasis is on use in radioisotope thermoelectric generators (RTGs) and dynamic cycle power units. The selected IHS design incorporates technologies developed for prior space and terrestrial IHSs to minimize development cost and span time. A General Purpose Heat Source (GPHS) Fueled Clad (FC), comprised of a plutonium-238 enriched pressed-plutonia pellet contained within a vented iridium clad, is the source for thermal energy. The GPHS FC technology was developed by DOE for use in space RTGs. The GPHS FC is, in turn, enclosed within a three-layer cladding system similar to that developed by DOE for earlier terrestrial heat sources. The cladding system provides for retention of the helium gas generated by the decay of the isotopic fuel and containment of the isotopic fuel under normal operating and accident conditions. Test hardware is currently being fabricated and safety demonstration testing is scheduled to be completed in early 1995. {copyright} 1995 {ital American} {ital Institute} {ital of} {ital Physics}

  16. Development of a Residential Ground-Source Integrated Heat Pump

    SciTech Connect

    Rice, C Keith; Baxter, Van D; Hern, Shawn; McDowell, Tim; Munk, Jeffrey D; Shen, Bo

    2013-01-01

    A residential-size ground-source integrated heat pump (GSIHP) system has been developed and is currently being field tested. The system is a nominal 2-ton (7 kW) cooling capacity, variable-speed unit, which is multi-functional, e.g. space cooling, space heating, dedicated water heating, and simultaneous space cooling and water heating. High-efficiency brushless permanent-magnet (BPM) motors are used for the compressor, indoor blower, and pumps to obtain the highest component performance and system control flexibility. Laboratory test data were used to calibrate a vapor-compression simulation model (HPDM) for each of the four primary modes of operation. The model was used to optimize the internal control options and to simulate the selected internal control strategies, such as controlling to a constant air supply temperature in the space heating mode and a fixed water temperature rise in water heating modes. Equipment performance maps were generated for each operation mode as functions of all independent variables for use in TRNSYS annual energy simulations. These were performed for the GSIHP installed in a well-insulated 2600 ft2(242 m2) house and connected to a vertical ground loop heat exchanger(GLHE). We selected a 13 SEER (3.8 CSPF )/7.7 HSPF (2.3 HSPF, W/W) ASHP unit with 0.90 Energy Factor (EF) resistance water heater as the baseline for energy savings comparisons. The annual energy simulations were conducted over five US climate zones. In addition, appropriate ground loop sizes were determined for each location to meet 10-year minimum and maximum design entering water temperatures (EWTs) to the equipment. The prototype GSIHP system was predicted to use 52 to 59% less energy than the baseline system while meeting total annual space conditioning and water heating loads.

  17. Desiccant Humidity Control System Using Waste Heat of Water Source Heat Pump

    NASA Astrophysics Data System (ADS)

    Wada, Kazuki; Mashimo, Kouichi; Takahashi, Mikio; Tanaka, Kitoshi; Toya, Saburo; Tateyama, Ryotaro; Miyamoto, Kazuhiro; Yamaguchi, Masahiro

    The authors hope to develop an air-conditioning system that processes the latent heat load and the sensible heat load separately. This would enable the efficiency of the chilling unit to be improved because the temperature of the chilled water used for cooling would be higher than normal. However, if lukewarm water is used, there is insufficient cooling and dehumidification. Therefore, a dehumidifier such as a desiccant air-conditioning system is needed. Using the waste heat generated when the desiccant air-conditioning system is in operation increases efficiency. The authors are developing a prototype desiccant humidity control system that makes use of the waste heat generated by a water source heat pump. This paper describes the results of an experiment that was conducted for this prototype based on the assumption that it would be installed in an office building. The dehumidification performance achieved was sufficient to process the indoor latent heat load. The prototype was able to adjust the indoor relative humidity from 40% to 60% under conditions in which the indoor latent heat load varied. Humidification without the use of water was possible even in the absence of an indoor latent heat load when the outdoor absolute humidity was 3.5 g/kg' or more.

  18. The impact of municipal waste combustion in small heat sources

    NASA Astrophysics Data System (ADS)

    Vantúch, Martin; Kaduchová, Katarína; Lenhard, Richard

    2016-06-01

    At present there is a tendency to make greater use for heating houses for burning solid fuel, such as pieces of wood, coal, coke, local sources of heat to burn natural gas. This tendency is given both the high price of natural gas as well as the availability of cheaper solid fuel. In many cases, in the context saving heating costs, respectively in the context of the disposal of waste is co-incinerated with municipal solid fuels and wastes of different composition. This co entails increased production emissions such as CO (carbon monoxide), NOx (nitrogen oxides), particulate matter (particulate matter), PM10, HCl (hydrogen chloride), PCDD/F (polychlorinated dibenzodioxins and dibenzofurans), PCBs (polychlorinated biphenyls) and others. The experiment was focused on the emission factors from the combustion of fossil fuels in combination with municipal waste in conventional boilers designed to burn solid fuel.

  19. Recent progress in understanding the regional characteristics of mineral dust composition and identification of source regions

    NASA Astrophysics Data System (ADS)

    Formenti, P.

    2009-04-01

    The environmental and climatic impacts of mineral dust particles issued from arid and semi-arid regions of the globe strongly depend on their physico-chemical properties, that is, composition, size distribution, and shape. Mineral dust particles are mainly aggregates of silicates (quartz, clay minerals, feldspars) and carbonates (calcite, dolomite, gypsum) with diameters up to tenths of microns. Surface and bulk chemical compositions determine their optical properties regarding scattering and absorption of solar and terrestrial radiation, but also their role in supplying nutrient to the ocean water. The surface chemistry (hygroscopicity, coatings, etc) also determine their ability to act as cloud condensation- and ice nuclei, and thus affect cloud and precipitation formation. Finally, they offer reaction and adsorption surface for numerous organic and inorganic reactions of particulate matter and trace gases; therefore, playing an important role in the removal of atmospheric trace and pollution constituents. In this presentation we will focus on the regional variability of the elemental bulk composition of mineral dust which is needed to predict the variability of its impacts at the regional and continental scales. The current state of knowledge is mainly determined by numerous investigations from the Sahara and from the Chinese deserts. Many conclusions are based on measurements performed in surface air or in the lower boundary layer over the deserts and adjacent oceans. Compositional differences (elemental, mineral and isotopic) of desert aerosol are strong indicators for distinct major regions. Source apportionment seems to be possible using compositional data for a local and regional type of transport. During long-range transport, source characteristics can get lost when large scale mixing is taking place. Any final conclusion regarding the actual source requires additional application of tools like 3-D air mass trajectory analysis, use of satellite imagery etc

  20. Investigation of Hypersonic Laminar Heating Augmentation in the Stagnation Region

    NASA Technical Reports Server (NTRS)

    Marineau, Eric C.; Lewis, Daniel R.; Smith, Michael S.; Lafferty, John F.; White, Molly E.; Amar, Adam J.

    2012-01-01

    Laminar stagnation region heating augmentation is investigated in the AEDC Tunnel 9 at Mach 10 by performing high frequency surface pressure and heat transfer measurements on the Orion CEV capsule at zero degree angle-of-attack for unit Reynolds numbers between 0.5 and 15 million per foot. Heating augmentation increases with Reynolds number, but is also model size dependent as it is absent on a 1.25-inch diameter model at Reynolds numbers where it reaches up to 15% on a 7-inch model. Heat transfer space-time correlations on the 7-inch model show that disturbances convect at the boundary layer edge velocity and that the streamwise integral scale increases with distance. Therefore, vorticity amplification due to stretching and piling-up in the stagnation region appears to be responsible for the stagnation point heating augmentation on the larger model. This assumption is reinforced by the f(exp -11/3) dependence of the surface pressure spectrum compared to the f(exp -1) dependence in the free stream. Vorticity amplification does not occur on the 1.25- inch model because the disturbances are too large. Improved free stream fluctuation measurements will be required to determine if significant vorticity is present upstream or mostly generated behind the bow shock.

  1. EVIDENCE OF IMPULSIVE HEATING IN ACTIVE REGION CORE LOOPS

    SciTech Connect

    Tripathi, Durgesh; Mason, Helen E.; Klimchuk, James A.

    2010-11-01

    Using a full spectral scan of an active region from the Extreme-Ultraviolet Imaging Spectrometer (EIS) we have obtained emission measure EM(T) distributions in two different moss regions within the same active region. We have compared these with theoretical transition region EMs derived for three limiting cases, namely, static equilibrium, strong condensation, and strong evaporation from Klimchuk et al. The EM distributions in both the moss regions are strikingly similar and show a monotonically increasing trend from log T[K] = 5.15-6.3. Using photospheric abundances, we obtain a consistent EM distribution for all ions. Comparing the observed and theoretical EM distributions, we find that the observed EM distribution is best explained by the strong condensation case (EM{sub con}), suggesting that a downward enthalpy flux plays an important and possibly dominant role in powering the transition region moss emission. The downflows could be due to unresolved coronal plasma that is cooling and draining after having been impulsively heated. This supports the idea that the hot loops (with temperatures of 3-5 MK) seen in the core of active regions are heated by nanoflares.

  2. North Village Ground Source Heat Pump Demonstration Project

    SciTech Connect

    Redderson, Jeff

    2015-08-03

    This project demonstrated the feasibility of converting from a traditional direct exchange system to a ground source heat pump system on a large scale, multiple building apartment complex on a university campus. A total of ten apartment buildings were converted using vertical well fields and a ground source loop that connected the 24 apartments in each building into a common system. The system has yielded significant operational savings in both energy and maintenance and transformed the living environments of these residential buildings for our students.

  3. Overview of the Lombardy Region (I) Source Apportionment Study

    NASA Astrophysics Data System (ADS)

    Larsen, B. R.

    2009-04-01

    analysis of 700 filters including the bulk compounds OC, EC, nitrate, sulfate and ammonium together with a number of source marker compounds such as levoglucosan, K, Rb, PAH (wood combustion); linear alkanes (fuel/biogenic emissions); (Fe, Cu, Sn, Sb, and Mo (break-ware); Ce, Rh, Pt, and Pd (vehicle exhaust catalysts), Ca, Al, Fe, Mg, K, Ti, Ce, and Sr (soil/dust re-suspension), Na, Cl (road salt); V and Ni (fuel oil); Zn (tire-ware/tire combustion); Fe, Mn, Cr (railroad steel abrasion). The 76 ± 33 ug/m3 average PM10 concentration over the whole region was apportioned into ‘Secondary Aerosol - mostly inorganics' (30-40%), 'Transport - including re-suspension' (30-40%), and 'Residential Heating - mostly wood burning' (10-18% - 28% in Sondrio) and shows that reduction of industrial emissions of inorganic gaseous PM precursors should not be left out of the regions PM abatement strategy. Minor specific sources were also revealed. A detailed presentation will be given of the obtained data and results for the nine sites in the Po Valley in comparison with the site in the Valtelline Valley (Sondrio).

  4. The partition of energy associated with tropical heat sources

    NASA Technical Reports Server (NTRS)

    Silva-Dias, P. L.; Paegle, J. N.

    1985-01-01

    Data sets derived from observations during the First GARP Global Experiment (FGGE) have permitted the study of the behavior of the tropical atmosphere to an extent not possible before. The present summary discusses characteristics of the tropical atmosphere which may be a result of tropical heating. It is shown that the meridional component of the divergent wind is of the same order of magnitude an he rotational meridional wind for the planetary tropical scales. Furthermore, the first and second internal modes dominate over most of the tropics, and it is shown that gravity and Kelvin codes are the main contributors to the total tropical divergence. Comparison with averaged station precipitation data and heating estimates obtained from Goddard Laboratory for Atmospheric Science (GLAS)/National Aeronautics and Space Administration (NASA) show good correspondence between areas with maximum internal mode energy and regions with pronounced latent heat release.

  5. Nanofluid Flow and Heat Transfer in Channel Entrance Region

    NASA Astrophysics Data System (ADS)

    Liu, Joseph T. C.; Puliti, Gianluca

    2014-11-01

    The present work uses the continuum description of nanofluid flow to study the flow, heat and mass transfer in the entrance and developing region of channels or tubes, where the viscous and heat conduction layers are thin and the heat transfer is much more intense than fully developed flow. Instead of supplementing the formulation with thermodynamic properties based on mixture calculations, use is made of recent molecular dynamical computations of such properties, specifically, the density and heat capacity of gold-water nanofluids. The more general formulation results, within the Rayleigh-Stokes (plug flow) approximation and perturbation for small volume fraction, show that the nanofluid density-heat capacity has an enormous effect in the inertia mechanism in causing the nanofluid temperature profile to steepen. The nanofluid thermal conductivity though has an explicit enhancement of the surface heat transfer rate has the almost hidden effect of stretching the nanofluid temperature profile thus giving the opposite effect of enhancement. Quantitative results for Gold-Water nanofluid is presented.

  6. The asteroidal source region of ordinary chondrites

    NASA Technical Reports Server (NTRS)

    Wetherill, G. W.

    1984-01-01

    The final, Earth-impacting orbits of ordinary chondritic meteorites have a very special distribution. By use of visual radiant and time of fall data, as well as photographic fireball orbits (1) it is inferred that chondrite perihelia are concentrated near 1 A.U., eccentricities are usually rather high (approximately 0.5), and inclinations are low (approximately 10 deg). Velocity selection resulting from atmospheric ablation plays a significant role in determining this orbital distribution, but by no means suffices to explain it. The observed distribution is a fragile one, and can easily be destroyed by Earth and Venus perturbations. This places severe constraints on the location of the original source bodies, of which these meteorites are fragments. New calculations were made of the expected distribution of final orbits from a range of initial sources, taking into consideration close encounter planetary perturbations, secular resonance, destruction by collision in space, and atmospheric ablation.

  7. Environmental Assessment of Ground Source Heat Pump Systems

    NASA Astrophysics Data System (ADS)

    Bayer, P.; Saner, D.; Juraske, R.; Kübert, M.

    2009-12-01

    Ground source heat pump systems (GSHPs) represent the most frequent geothermal application. Because of the economic and environmental benefits of GSHPs in comparison with other technologies for space-heating, cooling, and warm-water provision, an exponential growth rate for these systems is predicted for the coming decades. GSHPs are considered to have a low environmental impact. However, they are not fully renewable. Devices such as borehole heat exchangers have to be installed and maintained, and during operation a heat pump continuously consumes electricity from the grid. In order to assess the environmental benefits of such technologies, the complete life-cycle of all technological elements has to be examined. This life-cycle includes drilling, installation, operation and disposal phase of GSHP application, and all background process for device production, transport and power generation. This paper presents a comprehensive analysis of a GSHP life cycle. The environmental relevance of individual technological elements is rated for a number of environmental indicators, including CO2 savings potential, ozone layer depletion, soil ecotoxicological potential, and impacts on the local aquifer. The role of primary energy used for heat pump operation is discussed, and comparison is made with alternative conventional space-conditioning systems.

  8. Lunar Surface Stirling Power Systems Using Isotope Heat Sources

    NASA Technical Reports Server (NTRS)

    Schmitz, Paul C.; Penswick, L. Barry; Shaltens, Richard K.

    2010-01-01

    For many years, NASA has used the decay of plutonium-238 (Pu-238) (in the form of the General Purpose Heat Source (GPHS)) as a heat source for Radioisotope Thermoelectric Generators (RTGs), which have provided electrical power for many NASA missions. While RTGs have an impressive reliability record for the missions in which they have been used, their relatively low thermal to electric conversion efficiency and the scarcity of plutonium-238 (Pu-238) has led NASA to consider other power conversion technologies. NASA is considering returning both robotic and human missions to the lunar surface and, because of the long lunar nights (14.75 Earth days), isotope power systems are an attractive candidate to generate electrical power. NASA is currently developing the Advanced Stirling Radioisotope Generator (ASRG) as a candidate higher efficiency power system that produces greater than 160 W with two GPHS modules at the beginning of life (BOL) (32% efficiency). The ASRG uses the same Pu-238 GPHS modules, which are used in RTG, but by coupling them to a Stirling convertor provides a four-fold reduction in the number of GPHS modules. This study considers the use of americium-241 (Am-241) as a substitute for the Pu-238 in Stirling- convertor-based Radioisotope Power Systems (RPS) for power levels from tens of watts to 5 kWe. The Am-241 is used as a substitute for the Pu-238 in GPHS modules. Depending on power level, different Stirling heat input and removal systems are modeled. It was found that substituting Am-241 GPHS modules into the ASRG reduces power output by about one-fifth while maintaining approximately the same system mass. In order to obtain the nominal 160 W of electrical output of the Pu-238 ASRG requires 10 Am-241 GPHS modules. Higher power systems require changing from conductive coupling heat input and removal from the Stirling convertor to either pumped loops or heat pipes. Liquid metal pumped loops are considered as the primary heat transportation on the hot

  9. Effects of wake passing on stagnation region heat transfer

    NASA Astrophysics Data System (ADS)

    O'Brien, J. E.

    In the present experimental study, an annular-flow wind tunnel fitted with a spoked-wheel wake generator was used to ascertain both time-averaged and time-resolved effects of wake passing in a cylinder stagnation region; the cylindrical spokes generated wakes simulating those of a turbine inlet guide vanes. The time-averaged heat transfer results obtained indicate an asymmetric heat-transfer coefficient distribution about the stagnation line, with higher heat-transfer coefficients on the side corresponding to the suction side of the turbine blade. Spectra of the hot-film records indicate that vortex-shedding is a major contributor to the unsteady buffeting of the test-cylinder boundary layer at circumferential stations located at both + and -60 deg from the stagnation line, despite making only a minor contribution to the stagnation line itself.

  10. Urban heat islands in the subsurface as sustainable source for geothermal energy

    NASA Astrophysics Data System (ADS)

    Menberg, Kathrin; Bayer, Peter; Blum, Philipp

    2014-05-01

    heating capacity of the thermal anomalies in the subsurface of the individual cities. The potential heat content of the individual aquifers, which accumulated in the aquifer, could cover the space heating of the studied cities for 1.6-4.5 years. The evaluation of the heat flux processes in Cologne and Karlsruhe shows, that the heat loss from basements and heat input from increased GST are the dominant heat sources, while the other processes are only of minor importance for the regional subsurface warming. However, site-specific heat sources, such as sewage leakages or reinjections of thermal waste water are found to cause pronounced local heat anomalies. The overall annual thermal energy input into the urban aquifer accounts up to 2.4 PJ for the study area in Cologne and 1.5 PJ in Karlsruhe. Thus, nearly 20% of the space heating demand in Karlsruhe could theoretically be covered sustainably by recycling the annual anthropogenic heat input into the urban aquifer.

  11. Heat Transfer of Viscoelastic Fluid Flow due to Nonlinear Stretching Sheet with Internal Heat Source

    NASA Astrophysics Data System (ADS)

    Nandeppanavar, M. M.; Siddalingappa, M. N.; Jyoti, H.

    2013-08-01

    In the present paper, a viscoelastic boundary layer flow and heat transfer over an exponentially stretching continuous sheet in the presence of a heat source/sink has been examined. Loss of energy due to viscous dissipation of the non-Newtonian fluid has been taken into account in this study. Approximate analytical local similar solutions of the highly non-linear momentum equation are obtained for velocity distribution by transforming the equation into Riccati-type and then solving this sequentially. Accuracy of the zero-order analytical solutions for the stream function and velocity are verified by numerical solutions obtained by employing the Runge-Kutta fourth order method involving shooting. Similarity solutions of the temperature equation for non-isothermal boundary conditions are obtained in the form of confluent hypergeometric functions. The effect of various physical parameters on the local skin-friction coefficient and heat transfer characteristics are discussed in detail. It is seen that the rate of heat transfer from the stretching sheet to the fluid can be controlled by suitably choosing the values of the Prandtl number Pr and local Eckert number E, local viscioelastic parameter k*1 and local heat source/ sink parameter β*

  12. Anomalous electron heating effects on the E region ionosphere in TIEGCM

    NASA Astrophysics Data System (ADS)

    Liu, Jing; Wang, Wenbin; Oppenheim, Meers; Dimant, Yakov; Wiltberger, Michael; Merkin, Slava

    2016-03-01

    We have recently implemented a new module that includes both the anomalous electron heating and the electron-neutral cooling rate correction associated with the Farley-Buneman Instability (FBI) in the thermosphere-ionosphere electrodynamics global circulation model (TIEGCM). This implementation provides, for the first time, a modeling capability to describe macroscopic effects of the FBI on the ionosphere and thermosphere in the context of a first-principle, self-consistent model. The added heating sources primarily operate between 100 and 130 km altitude, and their magnitudes often exceed auroral precipitation heating in the TIEGCM. The induced changes in E region electron temperature in the auroral oval and polar cap by the FBI are remarkable with a maximum Te approaching 2200 K. This is about 4 times larger than the TIEGCM run without FBI heating. This investigation demonstrates how researchers can add the important effects of the FBI to magnetosphere-ionosphere-thermosphere models and simulators.

  13. Heated birthing pools as a source of Legionnaires' disease.

    PubMed

    Collins, S L; Afshar, B; Walker, J T; Aird, H; Naik, F; Parry-Ford, F; Phin, N; Harrison, T G; Chalker, V J; Sorrell, S; Cresswell, T

    2016-03-01

    In June 2014 Public Health England confirmed a case of Legionnaires' disease (LD) in a neonate following birth at home in a hired birthing pool incorporating a heater and a recirculation pump which had been filled in advance of labour. The case triggered a public health investigation and a microbiological survey of an additional ten heated birthing pools hired or recently hired to the general public across England. The birthing pool used by the parent of the confirmed case was identified as the source of the neonate's infection following detection of Legionella pneumophila ST48 in both patient and environmental samples. Legionella species were detected by quantitative polymerase chain reaction but not culture in a further three pools together with other opportunistic pathogens identified by culture and matrix-assisted laser desorption ionization-time of flight (MALDI-ToF) mass spectrometry. A Patient Safety Alert from NHS England and Public Health England was issued stating that heated birthing pools filled in advance of labour should not be used for home births. This recommendation remains in place. This investigation in conjunction with other recent reports has highlighted a lack of awareness regarding the microbiological safety of heated birthing pools and their potential to be a source of LD and other opportunistic infections. Furthermore, the investigation raised important considerations with regards to microbiological sampling and testing in such incidents. Public health authorities and clinicians should consider LD in the differential diagnosis of severe respiratory infection in neonates within 14 days of a water birth. PMID:26289365

  14. Nondestructive inspection of General Purpose Heat Source (GPHS) girth welds

    SciTech Connect

    Reimus, M.A.H.; George, T.G.; Lynch, C.

    1998-12-31

    The General-Purpose Heat Source (GPHS) provides power for space missions by transmitting the heat of {sup 238}Pu decay to an array of thermoelectric elements. The GPHS is fabricated using iridium capsules, TIG welded, to contain the {sup 238}PuO{sub 2} fuel pellet. GPHS capsules will be utilized in the upcoming Cassini mission to explore Saturn and its moons. The physical integrity of the girth weld is important to mission safety and performance. Since experience in the past had revealed a potential for initiation of small cracks in the girth weld overlap zone, a nondestructive inspection of the capsule weld is required. A ultrasonic method was used to inspect the welds of capsules fabricated for the Galileo mission. The instrument, transducer, and method used were state of the art at the time (early 1980s). The ultrasonic instrumentation and methods used to inspect the Cassini GPHSs was significantly upgraded from those used for the Galileo mission. GPHSs that had ultrasonic reflectors that exceeded the reject specification level were subsequently inspected with radiography to provide additional engineering data used to accept/reject the heat source. This paper describes the Galileo-era ultrasonic instrumentation and methods and the subsequent upgrades made to support testing of Cassini GPHSs. Also discussed is the data obtained from radiographic examination and correlation to ultrasonic examination results.

  15. Ground-source heat pump case studies and utility programs

    SciTech Connect

    Lienau, P.J.; Boyd, T.L.; Rogers, R.L.

    1995-04-01

    Ground-source heat pump systems are one of the promising new energy technologies that has shown rapid increase in usage over the past ten years in the United States. These systems offer substantial benefits to consumers and utilities in energy (kWh) and demand (kW) savings. The purpose of this study was to determine what existing monitored data was available mainly from electric utilities on heat pump performance, energy savings and demand reduction for residential, school and commercial building applications. In order to verify the performance, information was collected for 253 case studies from mainly utilities throughout the United States. The case studies were compiled into a database. The database was organized into general information, system information, ground system information, system performance, and additional information. Information was developed on the status of demand-side management of ground-source heat pump programs for about 60 electric utility and rural electric cooperatives on marketing, incentive programs, barriers to market penetration, number units installed in service area, and benefits.

  16. PBMR as an Ideal Heat Source for High-Temperature Process Heat Applications

    SciTech Connect

    Correia, Michael; Greyvenstein, Renee; Silady, Fred; Penfield, Scott

    2006-07-01

    The Pebble Bed Modular Reactor (PBMR) is an advanced helium-cooled, graphite-moderated High Temperature Gas-cooled Reactor (HTGR). A 400 MWt PBMR Demonstration Power Plant (DPP) for the production of electricity is being developed in South Africa. This PBMR technology is also an ideal heat source for process heat applications, including Steam Methane Reforming, steam for Oil Sands bitumen recovery, Hydrogen Production and co-generation (process heat and/or electricity and/or process steam) for petrochemical industries. The cycle configuration used to transport the heat of the reactor to the process plant or to convert the reactor's heat into electricity or steam directly influences the cycle efficiency and plant economics. The choice of cycle configuration depends on the process requirements and is influenced by practical considerations, component and material limitations, maintenance, controllability, safety, performance, risk and cost. This paper provides an overview of the use of a PBMR reactor for process applications and possible cycle configurations are presented for applications which require high temperature process heat and/or electricity. (authors)

  17. HTGR nuclear heat source component design and experience

    SciTech Connect

    Peinado, C.O.; Wunderlich, R.G.; Simon, W.A.

    1982-05-01

    The high-temperature gas-cooled reactor (HTGR) nuclear heat source components have been under design and development since the mid-1950's. Two power plants have been designed, constructed, and operated: the Peach Bottom Atomic Power Station and the Fort St. Vrain Nuclear Generating Station. Recently, development has focused on the primary system components for a 2240-MW(t) steam cycle HTGR capable of generating about 900 MW(e) electric power or alternately producing high-grade steam and cogenerating electric power. These components include the steam generators, core auxiliary heat exchangers, primary and auxiliary circulators, reactor internals, and thermal barrier system. A discussion of the design and operating experience of these components is included.

  18. Low Temperature Heat Source Utilization Current and Advanced Technology

    SciTech Connect

    Anderson, James H. Jr.; Dambly, Benjamin W.

    1992-06-01

    Once a geothermal heat source has been identified as having the potential for development, and its thermal, physical, and chemical characteristics have been determined, a method of utilization must be decided upon. This compendium will touch upon some of these concerns, and hopefully will provide the reader with a better understanding of technologies being developed that will be applicable to geothermal development in East Africa, as well as other parts of the world. The appendices contain detailed reports on Down-the-Well Turbo Pump, The Vapor-Turbine Cycle for Geothermal Power Generation, Heat Exchanger Design for Geothermal Power Plants, and a Feasibility Study of Combined Power and Water Desalting Plant Using Hot Geothermal Water. [DJE-2005

  19. Physical Conditions in the Source Region of a Zebra Structure

    NASA Astrophysics Data System (ADS)

    Yasnov, L. V.; Karlický, M.; Stupishin, A. G.

    2016-07-01

    We analyze the physical conditions in the source region of a zebra structure, observed with the Ondřejov radiospectrograph during the 1 August 2010 solar flare. To determine the gyro-frequency harmonic numbers of the observed zebra lines, we compute the magnetic field strength, the electron density, and their spatial scales in the source region of the zebra structure. The region where the flare occurred is analyzed using EUV (171 Å and 335 Å) observations. To determine the conditions in the zebra source region, the magnetic field structure is reconstructed using observed photospheric magnetic field data. By computing the dependence of the magnetic field vs. height in this reconstruction and by comparing the magnetic field strength derived from the zebra structure, we determine the dependence of the electron density vs. height in the zebra source-region. We identify the loops where the zebra structure was generated at heights of about 2.5 - 3.3 Mm. Assuming the barometric law for the electron density, we determine the temperature in the zebra source-region to be T ≈ 2.0 × 104 K. Comparing the obtained values of the temperature and electron density in the zebra source-region with a model of the solar atmosphere, we find that the zebra structure was generated in the transition region, in agreement with our previous results.

  20. Physical Conditions in the Source Region of a Zebra Structure

    NASA Astrophysics Data System (ADS)

    Yasnov, L. V.; Karlický, M.; Stupishin, A. G.

    2016-08-01

    We analyze the physical conditions in the source region of a zebra structure, observed with the Ondřejov radiospectrograph during the 1 August 2010 solar flare. To determine the gyro-frequency harmonic numbers of the observed zebra lines, we compute the magnetic field strength, the electron density, and their spatial scales in the source region of the zebra structure. The region where the flare occurred is analyzed using EUV (171 Å and 335 Å) observations. To determine the conditions in the zebra source region, the magnetic field structure is reconstructed using observed photospheric magnetic field data. By computing the dependence of the magnetic field vs. height in this reconstruction and by comparing the magnetic field strength derived from the zebra structure, we determine the dependence of the electron density vs. height in the zebra source-region. We identify the loops where the zebra structure was generated at heights of about 2.5 - 3.3 Mm. Assuming the barometric law for the electron density, we determine the temperature in the zebra source-region to be T ≈ 2.0 × 104~K. Comparing the obtained values of the temperature and electron density in the zebra source-region with a model of the solar atmosphere, we find that the zebra structure was generated in the transition region, in agreement with our previous results.

  1. Work output and efficiency at maximum power of linear irreversible heat engines operating with a finite-sized heat source.

    PubMed

    Izumida, Yuki; Okuda, Koji

    2014-05-01

    We formulate the work output and efficiency for linear irreversible heat engines working between a finite-sized hot heat source and an infinite-sized cold heat reservoir until the total system reaches the final thermal equilibrium state with a uniform temperature. We prove that when the heat engines operate at the maximum power under the tight-coupling condition without heat leakage the work output is just half of the exergy, which is known as the maximum available work extracted from a heat source. As a consequence, the corresponding efficiency is also half of its quasistatic counterpart. PMID:24856684

  2. Work Output and Efficiency at Maximum Power of Linear Irreversible Heat Engines Operating with a Finite-Sized Heat Source

    NASA Astrophysics Data System (ADS)

    Izumida, Yuki; Okuda, Koji

    2014-05-01

    We formulate the work output and efficiency for linear irreversible heat engines working between a finite-sized hot heat source and an infinite-sized cold heat reservoir until the total system reaches the final thermal equilibrium state with a uniform temperature. We prove that when the heat engines operate at the maximum power under the tight-coupling condition without heat leakage the work output is just half of the exergy, which is known as the maximum available work extracted from a heat source. As a consequence, the corresponding efficiency is also half of its quasistatic counterpart.

  3. Acoustic focusing by an array of heat sources in air

    NASA Astrophysics Data System (ADS)

    Ge, Yong; Sun, Hong-xiang; Liu, Chen; Qian, Jiao; Yuan, Shou-qi; Xia, Jian-ping; Guan, Yi-jun; Zhang, Shu-yi

    2016-06-01

    We report on a broadband acoustic focusing lens comprising 20 heat sources of different temperatures, 10 on each side of the array, in air. This focusing phenomenon is attributed to temperature gradients inducing the desired refractive index in one medium (air) and to the continuously changing acoustic impedance, which avoids any acoustic impedance difference that would occur between a lens and air. The results indicate that this focusing lens has a broader bandwidth (>3.5 kHz), higher intensity amplification (about 5.0 times), and a simpler structure. This focusing lens has great potential for applications in ultrasonic devices.

  4. Timing and heat sources for the Barrovian metamorphism, Scotland

    NASA Astrophysics Data System (ADS)

    Viete, Daniel R.; Oliver, Grahame J. H.; Fraser, Geoff L.; Forster, Marnie A.; Lister, Gordon S.

    2013-09-01

    New SHRIMP U/Pb zircon ages of 472.2 ± 5.8 Ma and 471.2 ± 5.9 Ma are presented for the age of peak metamorphism of Barrovian migmatites. 40Ar/39Ar ages for white mica from the Barrovian metamorphic series are presented, and are recalculated using recently-proposed revisions to the 40K decay constants to allow more precise and accurate comparison with U/Pb ages. The 40Ar/39Ar ages are found to vary systematically with increasing metamorphic grade, between c. 465 Ma for the biotite zone and c. 461 Ma for the sillimanite zone. There is no evidence for any significant metamorphic heating during the first 15 Myr of the Grampian Orogeny (before c. 473 Ma) or the final 4 Myr (after c. 465 Ma). The Barrovian metamorphism occurred over a period of ~ 8 Myr within the ~ 27-Myr Grampian Orogeny. The Barrovian metamorphism records punctuated heating, was temporally and spatially associated with large-scale bimodal magmatism, and developed within crust that was not overthickened. The temporally distinct nature of the Barrovian metamorphic episode within the Grampian Orogeny, and its heating pattern and tectonic context, are not consistent with significant heat contribution from thermal equilibration of overthickened crust. Rather, the Barrovian metamorphism records a transient phase of crustal thermal disequilibrium during the Grampian Orogeny. Temporal and spatial association with Grampian bimodal magmatism is consistent with production of the Barrovian metamorphic series within the middle crust as the result of advection of heat from the lower crust and/or mantle. The Barrovian metamorphic series - the classic example of ‘orogenic regional metamorphism’ - did not form in response to crustal thickening and thermal relaxation, but appears to record large-scale contact metamorphism.

  5. Transition Region Abundance Measurements During Impulsive Heating Events

    NASA Astrophysics Data System (ADS)

    Warren, Harry P.; Brooks, David H.; Doschek, George A.; Feldman, Uri

    2016-06-01

    It is well established that elemental abundances vary in the solar atmosphere and that this variation is organized by first ionization potential (FIP). Previous studies have shown that in the solar corona, low-FIP elements such as Fe, Si, Mg, and Ca, are generally enriched relative to high-FIP elements such as C, N, O, Ar, and Ne. In this paper we report on measurements of plasma composition made during impulsive heating events observed at transition region temperatures with the Extreme Ultraviolet Imaging Spectrometer (EIS) on Hinode. During these events the intensities of O iv, v, and vi emission lines are enhanced relative to emission lines from Mg v, vi, and vii and Si vi and vii, and indicate a composition close to that of the photosphere. Long-lived coronal fan structures, in contrast, show an enrichment of low-FIP elements. We conjecture that the plasma composition is an important signature of the coronal heating process, with impulsive heating leading to the evaporation of unfractionated material from the lower layers of the solar atmosphere and higher-frequency heating leading to long-lived structures and the accumulation of low-FIP elements in the corona.

  6. An Empirical Temperature Variance Source Model in Heated Jets

    NASA Technical Reports Server (NTRS)

    Khavaran, Abbas; Bridges, James

    2012-01-01

    An acoustic analogy approach is implemented that models the sources of jet noise in heated jets. The equivalent sources of turbulent mixing noise are recognized as the differences between the fluctuating and Favre-averaged Reynolds stresses and enthalpy fluxes. While in a conventional acoustic analogy only Reynolds stress components are scrutinized for their noise generation properties, it is now accepted that a comprehensive source model should include the additional entropy source term. Following Goldstein s generalized acoustic analogy, the set of Euler equations are divided into two sets of equations that govern a non-radiating base flow plus its residual components. When the base flow is considered as a locally parallel mean flow, the residual equations may be rearranged to form an inhomogeneous third-order wave equation. A general solution is written subsequently using a Green s function method while all non-linear terms are treated as the equivalent sources of aerodynamic sound and are modeled accordingly. In a previous study, a specialized Reynolds-averaged Navier-Stokes (RANS) solver was implemented to compute the variance of thermal fluctuations that determine the enthalpy flux source strength. The main objective here is to present an empirical model capable of providing a reasonable estimate of the stagnation temperature variance in a jet. Such a model is parameterized as a function of the mean stagnation temperature gradient in the jet, and is evaluated using commonly available RANS solvers. The ensuing thermal source distribution is compared with measurements as well as computational result from a dedicated RANS solver that employs an enthalpy variance and dissipation rate model. Turbulent mixing noise predictions are presented for a wide range of jet temperature ratios from 1.0 to 3.20.

  7. Effects of aqueous humor hydrodynamics on human eye heat transfer under external heat sources.

    PubMed

    Tiang, Kor L; Ooi, Ean H

    2016-08-01

    The majority of the eye models developed in the late 90s and early 00s considers only heat conduction inside the eye. This assumption is not entirely correct, since the anterior and posterior chambers are filled aqueous humor (AH) that is constantly in motion due to thermally-induced buoyancy. In this paper, a three-dimensional model of the human eye is developed to investigate the effects AH hydrodynamics have on the human eye temperature under exposure to external heat sources. If the effects of AH flow are negligible, then future models can be developed without taking them into account, thus simplifying the modeling process. Two types of external thermal loads are considered; volumetric and surface irradiation. Results showed that heat convection due to AH flow contributes to nearly 95% of the total heat flow inside the anterior chamber. Moreover, the circulation inside the anterior chamber can cause an upward shift of the location of hotspot. This can have significant consequences to our understanding of heat-induced cataractogenesis. PMID:27340100

  8. Two possible source regions for central Greenland last glacial dust

    NASA Astrophysics Data System (ADS)

    Újvári, Gábor; Stevens, Thomas; Svensson, Anders; Klötzli, Urs S.; Manning, Christina; Németh, Tibor; Kovács, János; Sweeney, Mark R.; Gocke, Martina; Wiesenberg, Guido L. B.; Markovic, Slobodan B.; Zech, Michael

    2015-12-01

    Dust in Greenland ice cores is used to reconstruct the activity of dust-emitting regions and atmospheric circulation. However, the source of dust material to Greenland over the last glacial period is the subject of considerable uncertainty. Here we use new clay mineral and <10 µm Sr-Nd isotopic data from a range of Northern Hemisphere loess deposits in possible source regions alongside existing isotopic data to show that these methods cannot discriminate between two competing hypothetical origins for Greenland dust: an East Asian and/or central European source. In contrast, Hf isotopes (<10 µm fraction) of loess samples show considerable differences between the potential source regions. We attribute this to a first-order clay mineralogy dependence of Hf isotopic signatures in the finest silt/clay fractions, due to absence of zircons. As zircons would also be absent in Greenland dust, this provides a new way to discriminate between hypotheses for Greenland dust sources.

  9. Temperature Profiles Along the Root with Gutta-percha Warmed through Different Heat Sources

    PubMed Central

    Simeone, Michele; Santis, Roberto De; Ametrano, Gianluca; Prisco, Davide; Borrelli, Marino; Paduano, Sergio; Riccitiello, Francesco; Spagnuolo, Gianrico

    2014-01-01

    Objectives: To evaluate temperature profiles developing in the root during warm compaction of gutta-percha with the heat sources System B and System MB Obtura (Analityc Technology, Redmond, WA, USA). Thirty extracted human incisor teeth were used. Root canals were cleaned and shaped by means of Protaper rotary files (Dentsply-Maillefer, Belgium), and imaging was performed by micro-CT (Skyscan 1072, Aartselaar, Belgium). Methods: Teeth were instrumented with K-type thermocouples, and the roots were filled with thermoplastic gutta-percha. Vertical compaction was achieved through the heat sources System B and System MB, and temperature profiles were detect-ed by means of NI Dac Interface controlled by the LabView System. With both heat sources, higher temperature levels were recorded in the region of the root far from the apex. When the warm plugger tip was positioned at a distance of 3 mm from the root apex, temperature levels of about 180°C were used to soften gutta-percha, and no statistically significant differences were observed between peak temperatures developed by the two heating sources at the root apex. However, a temperature level higher than 40°C was maintained for a longer time with System MB. Results: Statistically significant differences were observed in peak temperature levels recorded far from the root apex. Thus, with a temperature of about 180°C and the warm plugger positioned at 3 mm from the root apex, both heating sources led to a temperature slightly higher than 40°C at the apex of the root, suggesting that the gutta-percha was properly softened. Significance: A temperature level higher than 40°C was maintained for a longer time with System MB, thus providing an ad-equate time for warm compaction of the gutta-percha. PMID:25614768

  10. Transition Region and Chromospheric Signatures of Impulsive Heating Events

    NASA Astrophysics Data System (ADS)

    Warren, Harry; Reep, Jeffrey; Crump, Nicholas

    2016-05-01

    We exploit the high spatial resolution and high cadence of the Interface Region Imaging Spectrograph (IRIS) to investigate the response of the transition region and chromosphere to energy deposition during several small flares. We find that during the impulsive phase of these events the intensities of the C II 1334.535 and Si IV 1402.770 A emission lines are characterized by numerous, small-scale impulsive bursts typically lasting 60 s or less followed by a slower decay over several minutes. These variations in intensity are usually accompanied by impulsive redshifts of 20–40 km/s, although some blueshifted profiles are also observed. For one particularly well observed event we combine the IRIS observations with co-temporal measurements of hard X-ray emission from RHESSSI, transition region density from EIS, and high-temperature coronal loops with XRT and AIA to constrain 1D hydrodynamic models of loop evolution. Many aspects of the observations can be explained with simple heating scenarios, but some cannot. The simulated Doppler shifts, for example, show very short-duration redshifts during the initial phase of the heating while the observed redshifts persist over several minutes.

  11. Effects of source-region phenomenology on seismic discrimination

    NASA Astrophysics Data System (ADS)

    Taylor, S. R.

    1992-06-01

    Seismic discrimination and yield-estimation studies have demonstrated the importance of explosion-source region phenomenology to the monitoring of nuclear test ban treaties. In this paper, we examine source-region factors that control spectral ratio discrimination of NTS nuclear explosions and western US earthquakes. We discuss how near-source geology controls the shape of the spectral-ratio curve for explosions. An explosion-source model derived by Denny and Johnson (1991) is used to fit the spectral-ratio data and illustrates the dependence of the pressure-time history acting at the elastic radius on the physical state of the materials on the near-source region. We then summarize two detailed studies of a missed violation (a nuclear explosion that looks like an earthquake) and a false alarm (a naturally occurring event that looks like a nuclear explosion). In both cases, source-region effects could be modeled that resulted in the radiation of anomalous seismic spectrum. These studies underscore the importance that an improved understanding of source-region phenomenology has on predicting monitoring capabilities in widely different geologic environments, assessing opportunities for evasion, and for the resolution of false alarms.

  12. A capital cost comparison of commercial ground-source heat pump systems

    SciTech Connect

    Rafferty, K.

    1994-06-01

    The purpose of the report is to compare capital costs associated with the three designs of ground source heat pumps. Specifically, the costs considered are those associated with the heat source/heat sink or ground source portion of the system. In order to standardize the heat rejection over the three designs, it was assumed that the heat pump loop would operate at a temperature range of 85{degree} (to the heat pumps) to 95{degree} (from the heat pumps) under peak conditions. The assumption of constant loop temperature conditions for all three permits an apples-to-apples comparison of the alternatives.

  13. Emission Measure Distribution and Heating of Two Active Region Cores

    NASA Technical Reports Server (NTRS)

    Tripathi, Durgesh; Klimchuk, James A.; Mason, Helen E.

    2011-01-01

    Using data from the Extreme-ultraviolet Imaging Spectrometer aboard Hinode, we have studied the coronal plasma in the core of two active regions. Concentrating on the area between opposite polarity moss, we found emission measure distributions having an approximate power-law form EM/T(exp 2.4) from log T = 5.55 up to a peak at log T = 6.57. The observations are explained extremely well by a simple nanoflare model. However, in the absence of additional constraints, the observations could possibly also be explained by steady heating.

  14. Source regional contributions to PM2.5 in a megacity in China using an advanced source regional apportionment method.

    PubMed

    Tian, Ying-Ze; Chen, Gang; Wang, Hai-Ting; Huang-Fu, Yan-Qi; Shi, Guo-Liang; Han, Bo; Feng, Yin-Chang

    2016-03-01

    To quantify contributions of individual source categories from diverse regions to PM2.5, PM2.5 samples were collected in a megacity in China and analyzed through a newly developed source regional apportionment (SRA) method. Levels, compositions and seasonal variations of speciated PM2.5 dataset were investigated. Sources were determined by Multilinear Engine 2 (ME2) model, and results showed that the PM2.5 in Tianjin was mainly influenced by secondary sulphate & secondary organic carbon SOC (percent contribution of 26.2%), coal combustion (24.6%), crustal dust & cement dust (20.3%), secondary nitrate (14.9%) and traffic emissions (14.0%). The SRA method showed that northwest region R2 was the highest regional contributor to secondary sources, with percent contributions to PM2.5 being 9.7% for secondary sulphate & SOC and 6.0% for secondary nitrates; the highest coal combustion was from local region R1 (6.2%) and northwest R2 (8.0%); the maximum contributing region to crustal & cement dust was southeast region R4 (5.0%); and contributions of traffic emissions were relatively spatial homogeneous. The seasonal variation of regional source contributions was observed: in spring, the crustal and cement dust contributed a higher percentage and the R4 was an important contributor; the secondary process attributed an increase fraction in summer; the mixed coal combustion from southwest R5 enhanced in autumn. PMID:26766363

  15. Recovery Act: Cedarville School District Retrofit of Heating and Cooling Systems with Geothermal Heat Pumps and Ground Source Water Loops

    SciTech Connect

    Jarrell, Mark

    2013-09-30

    Cedarville School District retrofitted the heating and cooling systems in three campus areas (High School, Middle School, and Upper Elementary School) with geothermal heat pumps and ground source water loops, as a demonstration project for the effective implementation of geothermal heat pump systems and other energy efficiency and air quality improvements.

  16. Plasmonic Photothermal Heating of Intraperitoneal Tumors through the Use of an Implanted Near-Infrared Source

    PubMed Central

    2013-01-01

    Plasmonic nanomaterials including gold nanorods are effective agents for inducing heating in tumors. Because near-infrared (NIR) light has traditionally been delivered using extracorporeal sources, most applications of plasmonic photothermal therapy have focused on isolated subcutaneous tumors. For more complex models of disease such as advanced ovarian cancer, one of the primary barriers to gold nanorod-based strategies is the adequate delivery of NIR light to tumors located at varying depths within the body. To address this limitation, a series of implanted NIR illumination sources are described for the specific heating of gold nanorod-containing tissues. Through computational modeling and ex vivo studies, a candidate device is identified and validated in a model of orthotopic ovarian cancer. As the therapeutic, imaging, and diagnostic applications of plasmonic nanomaterials progress, effective methods for NIR light delivery to challenging anatomical regions will complement ongoing efforts to advance plasmonic photothermal therapy toward clinical use. PMID:23961973

  17. Heat transfer in a turbulent separation region with superimposed stream pulsations

    NASA Astrophysics Data System (ADS)

    Davletshin, I. A.; Mikheev, N. I.; Molochnikov, V. M.

    2008-06-01

    Experimental data on heat transfer in turbulent separation region behind obstacle in a broad frequency range of superimposed free-stream pulsations are reported. The heat-transfer coefficient was determined by solving an inverse non-stationary heat conduction problem based on experimentally measured wall transient temperature. Substantial heat-transfer intensification in the separation region of the pulsating flow was identified.

  18. Ground Source Integrated Heat Pump (GS-IHP) Development

    SciTech Connect

    Baxter, V. D.; Rice, K.; Murphy, R.; Munk, J.; Ally, Moonis; Shen, Bo; Craddick, William; Hearn, Shawn A.

    2013-05-24

    Between October 2008 and May 2013 ORNL and ClimateMaster, Inc. (CM) engaged in a Cooperative Research and Development Agreement (CRADA) to develop a groundsource integrated heat pump (GS-IHP) system for the US residential market. A initial prototype was designed and fabricated, lab-tested, and modeled in TRNSYS (SOLAR Energy Laboratory, et al, 2010) to predict annual performance relative to 1) a baseline suite of equipment meeting minimum efficiency standards in effect in 2006 (combination of air-source heat pump (ASHP) and resistance water heater) and 2) a state-of-the-art (SOA) two-capacity ground-source heat pump with desuperheater water heater (WH) option (GSHPwDS). Predicted total annual energy savings, while providing space conditioning and water heating for a 2600 ft{sup 2} (242 m{sup 2}) house at 5 U.S. locations, ranged from 52 to 59%, averaging 55%, relative to the minimum efficiency suite. Predicted energy use for water heating was reduced 68 to 78% relative to resistance WH. Predicted total annual savings for the GSHPwDS relative to the same baseline averaged 22.6% with water heating energy use reduced by 10 to 30% from desuperheater contributions. The 1st generation (or alpha) prototype design for the GS-IHP was finalized in 2010 and field test samples were fabricated for testing by CM and by ORNL. Two of the alpha units were installed in 3700 ft{sup 2} (345 m{sup 2}) houses at the ZEBRAlliance site in Oak Ridge and field tested during 2011. Based on the steady-state performance demonstrated by the GS-IHPs it was projected that it would achieve >52% energy savings relative to the minimum efficiency suite at this specific site. A number of operational issues with the alpha units were identified indicating design changes needed to the system before market introduction could be accomplished. These were communicated to CM throughout the field test period. Based on the alpha unit test results and the diagnostic information coming from the field test

  19. On the efficient use of a lowtemperature heat source by the organic Rankine cycle

    NASA Astrophysics Data System (ADS)

    Mikielewicz, Dariusz; Mikielewicz, Jarosław

    2013-09-01

    The evaporation temperature is regarded as one of the major parameters influencing the organic Rankine cycle (ORC) efficiency. Majority of contributions in literature for ORC cycle analyses treat the heat source as if it had an infinite heat capacity. Such analyses are not valuable as the resulting temperature drops of the heat source needs to be small. That leads to the fact that the heat source is not well explored and in the case of waste heat utilization it can prove the poor economics of the ORC. In the present study cooperation of the ORC cycle with the heat source available as a single phase or phase changing fluids is considered. The analytical heat balance models have been developed, which enable in a simple way calculation of heating fluid temperature variation as well as the ratio of flow rates of heating and working fluids in ORC cycle. The developed analytical expressions enable also calculation of the outlet temperature of the heating fluid.

  20. Regional Heat Flow Map and the Continental Thermal Isostasy Understanding of México

    NASA Astrophysics Data System (ADS)

    Espinoza-Ojeda, O. M.; Harris, R. N.

    2014-12-01

    The first heat flow values made in Mexico were reported by Von Herzen [Science, 1963] for the marine environment and Smith [EPSL, 1974] for the continent. Since that time the number of measurements has increased greatly but are mostly from oil and gas exploration and in and around geothermal areas. We have compiled published values of conductive heat flow for Mexico and the Gulf of California to generate a new regional heat flow map consisting of 261 values. In addition to those original values, published heat flow sources include, Lee and Henyey [JGR, 1975], Lawver and Williams [JGR, 1979] Smith et al. [JGR, 1979], Lachenbruch et al. [JGR, 1985], and Ziagos et al. [JGR, 1985]. Although the geographic distribution is uneven, heat flow data are present in each of the eight main tectonic provinces. Our new compilation indicates relatively high regional heat flow averages in the Gulf Extensional Province (n=114, 92±22 mW/m2) and Mexican Basin and Range (n=21, 82±20 mW/m2) and are consistent with geologic estimates of extension. Lower regional averages are found in the Baja California Microplate (n=91, 75±19 mW/m2), the Sierra Madre Occidental (n=9, 75±12 mW/m2), the Sierra Madre Oriental (n=4, 68±15 mW/m2) and Mesa Central (n=X 77±23 mW/m2). In contrast low and variable heat flow value characterize the forearc region of the Middle America Trench (n=6, 35±16 mW/m2). A higher mean heat flow is associated with the Trans-Mexican Volcanic Belt (n=6, 78±26 mW/m2). Continental elevation results from a combination of buoyancy (i.e. compositional and thermal) and geodynamic forces. We combine these regional heat flow values with estimates of crustal thickness and density for each tectonic province and compute the thermal and compositional buoyancy following the approach of Hasterok and Chapman [JGR, 2007a,b]. We find that within uncertainties most provinces lie near the theoretical isostatic relationship with the exception of the Mesa Central and Sierra Madre del Sur

  1. Probing the severe haze pollution in three typical regions of China: Characteristics, sources and regional impacts

    NASA Astrophysics Data System (ADS)

    Wang, Qiongzhen; Zhuang, Guoshun; Huang, Kan; Liu, Tingna; Deng, Congrui; Xu, Jian; Lin, Yanfen; Guo, Zhigang; Chen, Ying; Fu, Qingyan; Fu, Joshua S.; Chen, Jiakuan

    2015-11-01

    PM2.5 with its major chemical components were measured and analyzed during a concurrent haze in Jan. 1-19, 2013 at three sites (Shanghai, Beijing, and Huaniao, a remote isle over the East China Sea) to probe the sources and formation process of such a severe haze over three typical regions in China. The mean PM2.5 concentrations during the severely polluted days reached 180.8 μg m-3, 299.2 μg m-3, and 131.1 μg m-3 in Shanghai, Beijing, and the Huaniao Isle, respectively. The mass ratio of the sum of SO42- , NO3-, and NH4+ to PM2.5 were over 1/3 during the polluted days at all the three sites. Promoted gas-to-particle transformations from acidic SO2 and NOx to SO42- and NO3- under high relative humidity conditions played a major role in the formation of this severe haze. Significant contribution of traffic emissions to the haze formation over China was suggested to be one of the major sources in triggering the heavy haze over China. Specifically, there was a more contribution from traffic in Shanghai than in Beijing as indicated by the higher NO3-/SO42- ratio in Shanghai. In Beijing, the enhanced coal combustion for winter heating along with the traffic emission was suggested to be the major two sources of this haze episode. Typical pollution elements such as As, Cd, and Pb as well as Cl- and K+ were substantially enhanced in the severely polluted days. Although the Huaniao Isle is located in the remote oceanic area as a background site, pollution elements, secondary ions, and K+ all increased substantially during the polluted days. As visualized by the backward air mass trajectories associated with the potential source region identification technique, air masses that passed over Northern China and Yangtze River Delta evidently invaded the offshore areas of Eastern China. The ratios of As, Cd, Cu, Zn, and K+ to Al at the Huaniao Isle were closer to those of Beijing rather than Shanghai, indicating that the marine aerosol over the East China Sea had been

  2. The planetary distribution of heat sources and sinks during FGGE

    NASA Technical Reports Server (NTRS)

    Johnson, D. R.; Wei, M. Y.

    1985-01-01

    Heating distributions from analysis of the National Meteorological Center and European Center for Medium Range Weather Forecasts data sets; methods used and problems involved in the inference of diabatic heating; the relationship between differential heating and energy transport; and recommendations on the inference of heat soruces and heat sinks for the planetary show are discussed.

  3. External Pressure Testing of the 60-Watt Isotopic Heat Source

    SciTech Connect

    Frazier, T. A.; Christenbury, S. T.

    1995-03-15

    The purpose of this manual is to establish the capability of the IHS generator system to contain its radioisotopic source under an accident scenario in which the generator is deposited in the ocean at great depth. This procedure is to be used on assemblies designated to demonstrate the capability of the 60-watt IHS in external pressure environments. A qualified helium leak technician (NDE) performs evaluations during post test activities. Quality Engineering (QE) is present during testing to monitor activities. Testing involves a 60-watt IHS/Heater Head Assembly with the simulant yttria in place of the isotopic fuel. The standard length 0.094 inch diameter SST dowel pin is replaced with a longer pin to facilitate disassembly. The assembly is tested to 1000 atmospheres (-15,000 psi). It is then evaluated. If it shows no evidence of collapse, an additional test is conducted for information only. The Source Document is "Safety Test Program Plan for the 60-Watt Isotopic Heat Source (IHS)", TBE-32156-IHS-008 Issue

  4. Regionalization of surface heat fluxes and evapotranspiration over heterogeneous landscape of the Third Pole region

    NASA Astrophysics Data System (ADS)

    Ma, Yaoming

    2016-04-01

    Like Antarctica and the Arctic, the Third Pole region is drawing increased attention among the international academic community. It is centered on the Tibetan Plateau, stretching from the Pamir Plateau and Hindu-Kush on the west to the Hengduan Mountains on the east, and from the Kunlun and Qilian Mts on the north to the Himalayas on the south. Covering over 5,000,000 km2 in total and with an average elevation surpassing 4000 m. The exchange of energy and evapotranspiration (ET) between land surface and atmosphere over the Third Pole region play an important role in the Asian monsoon system, which in turn is a major component of both the energy and water cycles of the global climate system. The parameterization methods based on satellite data and Atmospheric Boundary Layer (ABL) observations have been proposed and tested for deriving regional distribution of surface reflectance, surface temperature, net radiation flux, soil heat flux, sensible heat flux, latent heat flux and ET over heterogeneous landscape. As cases study, the methods were applied to the whole Tibetan Plateau area and Nepal area. To validate the proposed methods, the ground-measured surface reflectance, surface temperature, net radiation flux, soil heat flux, sensible heat flux and latent heat flux in the Third Pole Environment Programme (TPE) Research Platform (TPEP) TPEP are compared to the derived values. The results show that the derived surface variables, land surface heat fluxes and ET over the study area are in good accordance with the land surface status. These parameters show a wide range due to the strong contrast of surface features. And the estimated land surface variables and land surface heat fluxes are in good agreement with ground measurements, and all the absolute percent difference is less than 10% in the validation sites. It is therefore concluded that the proposed methods are successful for the retrieval of land surface variables and land surface heat fluxes over heterogeneous

  5. The role of heat source for spatio-temporal variations of mantle plumes

    NASA Astrophysics Data System (ADS)

    Kumagai, I.; Yamagishi, Y.; Davaille, A.

    2014-12-01

    Hot mantle plumes ascending from the core-mantle boundary experience a filtering effect by the endothermic phase change at the 660-km discontinuity. Fluid dynamics predicts that some hot mantle plumes stagnate at the phase boundary and locally heat the bottom of the upper mantle. This generates the secondary plumes in the upper mantle originating hotspots volcanic activities on the Earth's surface. Recently, seismic tomographic images around the upper-lower mantle boundary showed that the horizontal scale of the low velocity regions, which corresponds to that of the thermally buoyant heat sources, is the order of 100-1000 km. Although most of the fluid dynamic theories on the thermal plumes have been developed using an assumption that the heat source effect is negligible, the behaviors of the starting plumes in the upper mantle should depend on the size of heat source, which is generated by the hotter plume from the CMB. In order to understand the effects of heater size on the starting plume generation, we have experimentally investigated the behaviors of thermally buoyant plumes using a localized heat source (circular plate heater). The combination of quantitative visualization techniques of temperature (Thermochromic Liquid Crystals) and velocity (Particle Image Velocimetry) fields reveals the transient nature of the plume evolution: a variety of the spatio-tempotal distribution of plumes. Simple scaling laws for their ascent velocity and spacing of the plumes are experimentally determined. We also estimate the onset time of the secondary plumes in the upper mantle which depends on the local characteristics of the thermal boundary layer developing at the upper-lower mantle boundary.

  6. Environmental assessment for radioisotope heat source fuel processing and fabrication

    SciTech Connect

    Not Available

    1991-07-01

    DOE has prepared an Environmental Assessment (EA) for radioisotope heat source fuel processing and fabrication involving existing facilities at the Savannah River Site (SRS) near Aiken, South Carolina and the Los Alamos National Laboratory (LANL) near Los Alamos, New Mexico. The proposed action is needed to provide Radioisotope Thermoelectric Generators (RTG) to support the National Aeronautics and Space Administration's (NASA) CRAF and Cassini Missions. Based on the analysis in the EA, DOE has determined that the proposed action does not constitute a major Federal action significantly affecting the quality of the human environment within the meaning of the National Environmental Policy Act (NEPA) of 1969. Therefore, an Environmental Impact Statement is not required. 30 refs., 5 figs.

  7. Tabulation of Fundamental Assembly Heat and Radiation Source Files

    SciTech Connect

    T. deBues; J.C. Ryman

    2006-10-25

    The purpose of this calculation is to tabulate a set of computer files for use as input to the WPLOAD thermal loading software. These files contain details regarding heat and radiation from pressurized water reactor (PWR) assemblies and boiling water reactor (BWR) assemblies. The scope of this calculation is limited to rearranging and reducing the existing file information into a more streamlined set of tables for use as input to WPLOAD. The electronic source term files used as input to this calculation were generated from the output files of the SAS2H/ORIGIN-S sequence of the SCALE Version 4.3 modular code system, as documented in References 2.1.1 and 2.1.2, and are included in Attachment II.

  8. Hydrogen production from coal using a nuclear heat source

    NASA Technical Reports Server (NTRS)

    Quade, R. N.

    1976-01-01

    A strong candidate for hydrogen production in the intermediate time frame of 1985 to 1995 is a coal-based process using a high-temperature gas-cooled reactor (HTGR) as a heat source. Expected process efficiencies in the range of 60 to 70% are considerably higher than all other hydrogen production processes except steam reforming of a natural gas. The process involves the preparation of a coal liquid, hydrogasification of that liquid, and steam reforming of the resulting gaseous or light liquid product. A study showing process efficiency and cost of hydrogen vs nuclear reactor core outlet temperature has been completed, and shows diminishing returns at process temperatures above about 1500 F. A possible scenario combining the relatively abundant and low-cost Western coal deposits with the Gulf Coast hydrogen users is presented which provides high-energy density transportation utilizing coal liquids and uranium.

  9. Technology and fabrication of plutonium-238 radionuclide heat sources

    NASA Astrophysics Data System (ADS)

    Malikh, Y. A.; Aldoshin, A. I.; Danilkin, E. A.

    1996-03-01

    This paper outlines a brief technical description of the facility for production of plutonium-238 and fabrication of Radionuclide Heat Sources (RHS) containing Pu-238. Technical capabilities of the RHS fabrication facility are presented. The results of development of the RHS design for sea application are discussed. RHS fuel pellet comprises the tantalum shell with an annular slot intended for release of radiogenic helium and the Pu-238 dioxide core with reinforcing elements inside which contact with the shell. RHS is a double encapsulation consisting of the inner ``power'' capsule and the outer corrosion-resistant capsule. The chromium-nickel-molybdenum XH65MB alloy which is equivalent to Hastelloy-C alloy has been selected as a material for both capsules. Upon expiration of working life, RHS design is capable of withstanding the internal pressure of radiogenic helium at 1073 K within 30 minutes and the external hydrostatic pressure of 100 MPa at normal temperature.

  10. Dose distributions in regions containing beta sources: Uniform spherical source regions in homogeneous media

    SciTech Connect

    Werner, B.L.; Rahman, M.; Salk, W.N. ); Kwok, C.S. )

    1991-11-01

    The energy-averaged transport model for the calculation of dose rate distributions is applied to uniform, spherical source distributions in homogeneous media for radii smaller than the electron range. The model agrees well with Monte Carlo based calculations for source distributions with radii greater than half the continuous slowing down approximation range. The dose rate distributions can be written in the medical internal radiation dose (MIRD) formalism.

  11. Solar Jets as Sources of Outflows, Heating and Waves

    NASA Astrophysics Data System (ADS)

    Nishizuka, N.

    2013-05-01

    Recent space solar observations of the Sun, such as Hinode and SDO, have revealed that magnetic reconnection is ubiquitous in the solar atmosphere, ranging from small scale reconnection (observed as nanoflares) to large scale one (observed as long duration flares or giant arcades). Especially recent Hinode observations has found various types of tiny chromospheric jets, such as chromospheric anemone jets, penumbral microjets and light bridge jets from sunspot umbra. It was also found that the corona is full of tiny X-ray jets. Often they are seen as helical spinning jets with Alfvenic waves in the corona. Sometimes they are seen as chromospheric jets with slow-mode magnetoacoustic waves and sometimes as unresolved jet-like events at the footpoint of recurrent outflows and waves at the edge of the active region. There is increasing evidence of magnetic reconnection in these tiny jets and its association with waves. The origin of outflows and waves is one of the issues concerning coronal heating and solar wind acceleration. To answer this question, we had a challenge to reproduce solar jets with laboratory plasma experiment and directly measured outflows and waves. As a result, we could find a propagating wave excited by magnetic reconnection, whose energy flux is 10% of the released magnetic energy. That is enough for solar wind acceleration and locally enough for coronal heating, consistent with numerical MHD simulations of solar jets. Here we would discuss recent observations with Hinode, theories and experimental results related to jets and waves by magnetic reconnection, and discuss possible implication to reconnection physics, coronal heating and solar wind acceleration.

  12. Source-Type Identification Analysis Using Regional Seismic Moment Tensors

    NASA Astrophysics Data System (ADS)

    Chiang, A.; Dreger, D. S.; Ford, S. R.; Walter, W. R.

    2012-12-01

    Waveform inversion to determine the seismic moment tensor is a standard approach in determining the source mechanism of natural and manmade seismicity, and may be used to identify, or discriminate different types of seismic sources. The successful applications of the regional moment tensor method at the Nevada Test Site (NTS) and the 2006 and 2009 North Korean nuclear tests (Ford et al., 2009a, 2009b, 2010) show that the method is robust and capable for source-type discrimination at regional distances. The well-separated populations of explosions, earthquakes and collapses on a Hudson et al., (1989) source-type diagram enables source-type discrimination; however the question remains whether or not the separation of events is universal in other regions, where we have limited station coverage and knowledge of Earth structure. Ford et al., (2012) have shown that combining regional waveform data and P-wave first motions removes the CLVD-isotropic tradeoff and uniquely discriminating the 2009 North Korean test as an explosion. Therefore, including additional constraints from regional and teleseismic P-wave first motions enables source-type discrimination at regions with limited station coverage. We present moment tensor analysis of earthquakes and explosions (M6) from Lop Nor and Semipalatinsk test sites for station paths crossing Kazakhstan and Western China. We also present analyses of smaller events from industrial sites. In these sparse coverage situations we combine regional long-period waveforms, and high-frequency P-wave polarity from the same stations, as well as from teleseismic arrays to constrain the source type. Discrimination capability with respect to velocity model and station coverage is examined, and additionally we investigate the velocity model dependence of vanishing free-surface traction effects on seismic moment tensor inversion of shallow sources and recovery of explosive scalar moment. Our synthetic data tests indicate that biases in scalar

  13. Calculated temperatures in overthrust terrains and possible combinations of heat sources responsible for the tertiary granites in the greater Himalaya

    SciTech Connect

    Molnar, P.; Chen, W.; Padovani, E.

    1983-08-10

    There are three obvious sources of heat that affect the temperature in a region of thrust faulting: heat supplied from below the lower thrust plate, radiogenic heating within the crusts of both the upper and, especially, the lower plates, and frictional heating along the fault. We assume that heat is conducted primarily in the vertical direction and that solutions to the one-dimensional, time-dependent heat conduction equation can be used to describe the temperature field in overthrust zones. The effects of these three sources of heating can be isolated from one another, treated separately, and then combined in ratios proportional to various assumed rates of heating provided by each. We then use calculations for a range of possible combinations of heat sources that may have caused two-media granites of late Tertiary age in the Greater Himalaya. Because of the uncertainties in the age of the granites, in the depth at which they formed, in the amounts of heat flux supplied to the base of the lithosphere and of radiogenic heat production in the crust, inb the value of the coefficient of thermal conductivity and in other parameters, a broad range of possible combinations of parameters is possible. Temperature can reach the solidus for granite melts with various plausible combinations of parameters both that include no shear heating and that require frictional stresses of 100's of MPa on the Main Central Thrust. For instance, if the initial steady state geotherm in the crust now comprising the Himalaya were that of a typical shield, then frictional heating with a stress in excess of 100 MPa (1 kbar) would be necessary to raise the temperature of material near a thrust fault at 20 or 30 km depth to 650 /sup 0/C.

  14. Sources and sinks of carbon dioxide in the Arctic regions

    SciTech Connect

    Gosink, T. A.; Kelley, J. J.

    1982-01-01

    The data base required to adequately ascertain seasonal source and sink strengths in the arctic regions is difficult to obtain. However, there are now a reasonable quantity of data for this polar region to estimate sources and sinks within the Arctic which may contribute significantly to the annual tropospheric CO/sub 2/ concentration fluctuation. The sea-ice-air and the sea-air interfaces account for most of the contribution to the sources and sinks for carbon dioxide. Although the arctic and subarctic region is small in extent, it certainly is not impervious and ice sealed. Our estimate, based on historical data and current research, indicates that the Arctic, which is about 4% of the earth's surface, is an annual net sink for approx. 10/sup 15/ g CO/sub 2/ accounting for an equivalent of approx. 3% of the annual anthropogenic contribution of CO/sub 2/ to the troposphere.

  15. Collective Space-Charge Phenomena in the Source Region

    SciTech Connect

    Haber, I.; Bernal, S.; Celata, C.M.; Friedman, A.; Grote, D.P.; Kishek,R.A.; Quinn, B.; O'Shea, P.G.; Reiser, M.; Vay, J.-L.

    2004-09-18

    For many devices space-charge-dominated behavior, including the excitation of space-charge collective modes, can occur in the source region, even when the downstream characteristics are not space-charge-dominated. Furthermore, these modes can remain undamped for many focusing periods. Traditional studies of the source region in particle beam systems have emphasized the behavior of averaged beam characteristics, such as total current, rms beam size, or emittance, rather than the details of the full beam distribution function that are necessary to predict the excitation of collective modes. A primary tool for understanding the detailed evolution of a space-charge dominated beam in the source region has been the use of simulation in concert with detailed experimental measurement. However, ''first-principle'' simulations beginning from the emitter surface have often displayed substantial differences from what is measured. This is believed to result from sensitivities in the beam dynamics to small changes in the mechanical characteristics of the gun structure, as well as to similar sensitivities in the numerical methods. Simulations of the beam in the source region using the particle-in-cell WARP code and comparisons to experimental measurements at the University of Maryland are presented to illustrate the complexity in beam characteristics that can occur in the source region. In addition, direct measurement of the beam characteristics can be limited by lack of access to the source region or by difficulties in obtaining enough data to completely characterize the distribution function. Methods are therefore discussed for using simulation to infer characteristics of the beam distribution from the data that can be obtained.

  16. Measured Performance of a Low Temperature Air Source Heat Pump

    SciTech Connect

    R.K. Johnson

    2013-09-01

    A 4-ton Low Temperature Heat Pump (LTHP) manufactured by Hallowell International was installed in a residence near New Haven, Connecticut and monitored over two winters of operation. After attending to some significant service issues, the heat pump operated as designed. This report should be considered a review of the dual compressor “boosted heat pump” technology. The Low Temperature Heat Pump system operates with four increasing levels of capacity (heat output) as the outdoor temperature drops.

  17. Renewable energy sources for sustainable tourism in the Carpathian region

    NASA Astrophysics Data System (ADS)

    Mandryk, O. M.; Arkhypova, L. M.; Pobigun, O. V.; Maniuk, O. R.

    2016-08-01

    The use of renewable energy in sustainable tourism development of the region is grounded in the paper. There are three stages of selecting areas for projects of renewable energy sources: selection of potentially suitable area; consideration of exclusion criteria, detailed assessment of potential sites or areas. The factors of impact on spatial constraints and opportunities for building wind, solar and small hydro power plants on the parameters of sustainable tourism development in the Carpathian region were determined.

  18. Real-Time MEG Source Localization Using Regional Clustering.

    PubMed

    Dinh, Christoph; Strohmeier, Daniel; Luessi, Martin; Güllmar, Daniel; Baumgarten, Daniel; Haueisen, Jens; Hämäläinen, Matti S

    2015-11-01

    With its millisecond temporal resolution, Magnetoencephalography (MEG) is well suited for real-time monitoring of brain activity. Real-time feedback allows the adaption of the experiment to the subject's reaction and increases time efficiency by shortening acquisition and off-line analysis. Two formidable challenges exist in real-time analysis: the low signal-to-noise ratio (SNR) and the limited time available for computations. Since the low SNR reduces the number of distinguishable sources, we propose an approach which downsizes the source space based on a cortical atlas and allows to discern the sources in the presence of noise. Each cortical region is represented by a small set of dipoles, which is obtained by a clustering algorithm. Using this approach, we adapted dynamic statistical parametric mapping for real-time source localization. In terms of point spread and crosstalk between regions the proposed clustering technique performs better than selecting spatially evenly distributed dipoles. We conducted real-time source localization on MEG data from an auditory experiment. The results demonstrate that the proposed real-time method localizes sources reliably in the superior temporal gyrus. We conclude that real-time source estimation based on MEG is a feasible, useful addition to the standard on-line processing methods, and enables feedback based on neural activity during the measurements. PMID:25782980

  19. Cogeneration technology alternatives study. Volume 4: Heat Sources, balance of plant and auxiliary systems

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Data and information established for heat sources balance of plant items, thermal energy storage, and heat pumps are presented. Design case descriptions are given along with projected performance values. Capital cost estimates for representative cogeneration plants are also presented.

  20. Identifying meteorite source regions through near-Earth object spectroscopy

    NASA Astrophysics Data System (ADS)

    Thomas, Cristina A.; Binzel, Richard P.

    2010-02-01

    By virtue of their landing on Earth, meteorites reside in near-Earth object (NEO) orbits prior to their arrival. Thus the population of observable NEOs, in principle, gives important representation of meteorite source bodies. By linking meteorites to NEOs, and linking NEOs to their most likely main-belt source locations, we seek to gain insight into the original Solar System formation locations for different meteorite classes. To forge possible links between meteorites and NEOs, we have developed a three dimensional method for quantitative comparisons between laboratory measurements of meteorites and telescopic measurements of near-Earth objects. We utilize meteorite spectra from the Reflectance Experiment Laboratory (RELAB) database and NEO data from the SpeX instrument on the NASA Infrared Telescope Facility (IRTF). Using the Modified Gaussian Model (MGM) as a mathematical tool, we treat asteroid and meteorite spectra identically in the calculation of 1-μm and 2-μm Geometric Band Centers and their Band Area Ratios (BARs). Using these identical numerical parameters we quantitatively compare the spectral properties of S-, Sq-, Q- and V-type NEOs with the spectral properties of the meteorites in four classes: H, L, LL and HED. For each NEO spectrum, we assign a set of probabilities for it being related to each of these four meteorite classes. Our NEO-meteorite correlation probabilities are then convolved with NEO-source region probabilities to yield a final set of meteorite-source region correlations. While the ν6 resonance dominates the delivery for all four meteorite classes, an excess (significant at the 2.1-sigma level) source region signature is found for the H chondrites through the 3:1 mean motion resonance. This results suggest an H chondrite source with a higher than average delivery preference through the 3:1 resonance. A 3:1 resonance H chondrite source region is consistent with the short cosmic ray exposure ages known for H chondrites.

  1. Loop Heat Pipe Transient Behavior Using Heat Source Temperature for Set Point Control with Thermoelectric Converter on Reservoir

    NASA Technical Reports Server (NTRS)

    Ku, Jentung; Paiva, Kleber; Mantelli, Marcia

    2011-01-01

    The LHP operating temperature is governed by the saturation temperature of its reservoir. Controlling the reservoir saturation temperature is commonly done by cold biasing the reservoir and using electrical heaters to provide the required control power. With this method, the loop operating temperature can be controlled within 0.5K or better. However, because the thermal resistance that exists between the heat source and the LHP evaporator, the heat source temperature will vary with its heat output even if the LHP operating temperature is kept constant. Since maintaining a constant heat source temperature is of most interest, a question often raised is whether the heat source temperature can be used for LHP set point temperature control. A test program with a miniature LHP was carried out to investigate the effects on the LHP operation when the control temperature sensor was placed on the heat source instead of the reservoir. In these tests, the LHP reservoir was cold-biased and was heated by a control heater. Test results show that it was feasible to use the heat source temperature for feedback control of the LHP operation. In particular, when a thermoelectric converter was used as the reservoir control heater, the heat source temperature could be maintained within a tight range using a proportional-integral-derivative or on/off control algorithm. Moreover, because the TEC could provide both heating and cooling to the reservoir, temperature oscillations during fast transients such as loop startup could be eliminated or substantially reduced when compared to using an electrical heater as the control heater.

  2. Investigation of acoustic gravity waves created by anomalous heat sources: experiments and theoretical analysis

    NASA Astrophysics Data System (ADS)

    Pradipta, R.; Lee, M. C.

    2013-07-01

    We have been investigating high-power radio wave-induced acoustic gravity waves (AGWs) at Gakona, Alaska, using the High-frequency Active Aurora Research Program (HAARP) heating facility (i.e. HF heater) and extensive diagnostic instruments. This work was aimed at performing a controlled study of the space plasma turbulence triggered by the AGWs originating from anomalous heat sources, as observed in our earlier experiments at Arecibo, Puerto Rico (Pradipta 2007 MS Thesis MIT Press, Cambridge, MA). The HF heater operated in continuous wave (CW) O-mode can heat ionospheric plasmas effectively to yield a depleted magnetic flux tube as rising plasma bubbles (Lee et al 1998 Geophys. Res. Lett. 25 579). Two processes are responsible for the depletion of the magnetic flux tube: (i) thermal expansion and (ii) chemical reactions caused by heated ions. The depleted plasmas create large density gradients that can augment spread F processes via generalized Rayleigh-Taylor instabilities (Lee et al 1999 Geophys. Res. Lett. 26 37). It is thus expected that the temperature of neutral particles in the heated ionospheric region can be increased. Such a heat source in the neutral atmosphere may potentially generate AGWs in the form of traveling ionospheric plasma disturbances (TIPDs). We should point out that these TIPDs have features distinctively different from electric and magnetic field (ExB) drifts of HF wave-induced large-scale non-propagating plasma structures. Moreover, it was noted in our recent study of naturally occurring AGW-induced TIDs that only large-scale AGWs can propagate upward to reach higher altitudes. Thus, in our Gakona experiments we select optimum heating schemes for HF wave-induced AGWs that can be distinguished from the naturally occurring ones. The generation and propagation of AGWs are monitored by MUIR (Modular Ultra high-frequency Ionospheric Radar), Digisonde and GPS/low-earth-orbit satellites. Our theoretical and experimental studies have shown that

  3. Application of sorption heat pumps for increasing of new power sources efficiency

    NASA Astrophysics Data System (ADS)

    Vasiliev, L.; Filatova, O.; Tsitovich, A.

    2010-07-01

    In the 21st century the way to increase the efficiency of new sources of energy is directly related with extended exploration of renewable energy. This modern tendency ensures the fuel economy needs to be realized with nature protection. The increasing of new power sources efficiency (cogeneration, trigeneration systems, fuel cells, photovoltaic systems) can be performed by application of solid sorption heat pumps, regrigerators, heat and cold accumulators, heat transformers, natural gas and hydrogen storage systems and efficient heat exchangers.

  4. Biographical Sources: General, National, and Regional. Bibliographic Series No. 15.

    ERIC Educational Resources Information Center

    Roberts, Joan

    The sources for national, international, and regional general biographical materials held by the Arkansas University library which are listed include bibliographies, biographies, handbooks, dictionaries, and directories. The materials cited cover the United States, Canada, Latin America, Great Britain, France, Germany, Italy, Russia, Spain,…

  5. Regional source properties of the North Korean nuclear explosions

    NASA Astrophysics Data System (ADS)

    Hong, T.

    2009-12-01

    Seismic analyses based on regional waveforms receive increasing attention for discrimination and source studies of recent moderate-size underground nuclear explosions (UNEs). Two North Korean underground nuclear explosion tests were conducted in 9 October 2006 and 25 May 2009. The Noth Korean UNEs were well observed by dense regional seismic networks with high signal-to-noise ratios. The source properties of the two North Korean UNEs are estimated using source-spectral inversions of regional phases. Ray-path effects including attenuation are corrected in the inversion. The source properties of the UNEs are compared each other. The apparent moments of high-frequency regional phases of the 2009 UNE are estimated to be about 5 times greater than those of the 2006 UNE. The corner frequencies and overshoot parameters are determined to be similar between the UNEs. The North Korean UNEs are well discriminated from natural earthquakes using P/S spectral ratios. The S waves from the North Korean UNEs display fairly weak overshooting feature in the spectra unlike P waves.

  6. Mare basalt magma source region and mare basalt magma genesis

    SciTech Connect

    Binder, A.B.

    1982-11-15

    Given the available data, we find that the wide range of mare basaltic material characteristics can be explained by a model in which: (1) The mare basalt magma source region lies between the crust-mantle boundary and a maximum depth of 200 km and consists of a relatively uniform peridotite containing 73--80% olivine, 11--14% pyroxene, 4--8% plagioclase, 0.2--9% ilmenite and 1--1.5% chromite. (2) The source region consists of two or more density-graded rhythmic bands, whose compositions grade from that of the very low TiO/sub 2/ magma source regions (0.2% ilmenite) to that of the very high TiO/sub 2/ magma source regions (9% ilmenite). These density-graded bands are proposed to have formed as co-crystallizing olivine, pyroxene, plagioclase, ilmenite, and chromite settled out of a convecting magma (which was also parental to the crust) in which these crystals were suspended. Since the settling rates of the different minerals were governed by Stoke's law, the heavier minerals settled out more rapidly and therefore earlier than the lighter minerals. Thus the crystal assemblages deposited nearest the descending side of each convection cell were enriched in heavy ilmenite and chromite with respect to lighter olivine and pyroxene and very much lighter plagioclase. The reverse being the case for those units deposited near the ascending sides of the convection cells.

  7. Field Test of High Efficiency Residential Buildings with Ground-source and Air-source Heat Pump Systems

    SciTech Connect

    Ally, Moonis Raza; Munk, Jeffrey D; Baxter, Van D

    2011-01-01

    This paper describes the field performance of space conditioning and water heating equipment in four single-family residential structures with advanced thermal envelopes. Each structure features a different, advanced thermal envelope design: structural insulated panel (SIP); optimum value framing (OVF); insulation with embedded phase change materials (PCM) for thermal storage; and exterior insulation finish system (EIFS). Three of the homes feature ground-source heat pumps (GSHPs) for space conditioning and water heating while the fourth has a two-capacity air-source heat pump (ASHP) and a heat pump water heater (HPWH). Two of the GCHP-equipped homes feature horizontal ground heat exchange (GHX) loops that utillize the existing foundation and utility service trenches while the third features a vertical borehole with vertical u-tube GHX. All of the houses were operated under the same simulated occupancy conditions. Operational data on the house HVAC/Water heating (WH) systems are presented and factors influencing overall performance are summarized.

  8. Transverse Dimensions of Chorus in the Source Region

    NASA Technical Reports Server (NTRS)

    Santolik, O.; Gurnett, D. A.

    2003-01-01

    We report measurement of whistler-mode chorus by the four Cluster spacecraft at close separations. We focus our analysis on the generation region close to the magnetic equatorial plane at a radial distance of 4.4 Earth's radii. We use both linear and rank correlation analysis to define perpendicular dimensions of the sources of chorus elements below one half of the electron cyclotron frequency. Correlation is significant throughout the range of separation distances of 60-260 km parallel to the field line and 7-100 km in the perpendicular plane. At these scales, the correlation coefficient is independent for parallel separations, and decreases with perpendicular separation. The observations are consistent with a statistical model of the source region assuming individual sources as gaussian peaks of radiated power with a common half-width of 35 km perpendicular to the magnetic field. This characteristic scale is comparable to the wavelength of observed waves.

  9. local alternative sources for cogeneration combined heat and power system

    NASA Astrophysics Data System (ADS)

    Agll, Abdulhakim Amer

    Global demand for energy continues to grow while countries around the globe race to reduce their reliance on fossil fuels and greenhouse gas emissions by implementing policy measures and advancing technology. Sustainability has become an important issue in transportation and infrastructure development projects. While several agencies are trying to incorporate a range of sustainability measures in their goals and missions, only a few planning agencies have been able to implement these policies and they are far from perfect. The low rate of success in implementing sustainable policies is primarily due to incomplete understanding of the system and the interaction between various elements of the system. The conventional planning efforts focuses mainly on performance measures pertaining to the system and its impact on the environment but seldom on the social and economic impacts. The objective of this study is to use clean and alternative energy can be produced from many sources, and even use existing materials for energy generation. One such pathway is using wastewater, animal and organic waste, or landfills to create biogas for energy production. There are three tasks for this study. In topic one evaluated the energy saving that produced from combined hydrogen, heat, and power and mitigate greenhouse gas emissions by using local sustainable energy at the Missouri S&T campus to reduce energy consumption and fossil fuel usage. Second topic aimed to estimate energy recovery and power generation from alternative energy source by using Rankin steam cycle from municipal solid waste at Benghazi-Libya. And the last task is in progress. The results for topics one and two have been presented.

  10. Dose characterization in the near-source region for two high dose rate brachytherapy sources.

    PubMed

    Wang, Ruqing; Li, X Allen

    2002-08-01

    High dose rate (HDR) 192Ir sources are currently used in intravascular brachytherapy (IVB) for the peripheral arterial system. This poses a demand on evaluating accurate dose parameters in the near-source region for such sources. The purpose of this work is to calculate the dose parameters for the old VariSource HDR 192Ir source and the new microSelectron HDR 192Ir source, using Monte Carlo electron and photon transport simulation. The two-dimensional (2D) dose rate distributions and the air kerma strengths for the two HDR sources were calculated by EGSnrc and EGS4 Monte Carlo codes. Based on these data, the dose parameters proposed in the AAPM TG-60 protocol were derived. The dose rate constants obtained are 13.119+/-0.028 cGy h(-1) U(-1) for the old VariSource source, and 22.751+/-0.031 cGy h(-1) U(-1) for the new microSelectron source at the reference point (r0 = 2 mm, theta = pi/2). The 2D dose rate distributions, the radial dose functions, and the anisotropy functions presented for the two sources cover radial distances ranging from 0.5 to 10 mm. In the near-source region on the transverse plane, the dose effects of the charged particle nonequilibrium and the beta-particle dose contribution were studied. It is found that at radial distances ranging from 0.5 to 2 mm, these effects increase the calculated dose rates by up to 29% for the old VariSource source, and by up to 12% for the new microSelectron source, which, in turn, change values of the radial dose function and the anisotropy function. The present dose parameters, which account for the charged particle nonequilibrium and the beta particle contribution, may be used for accurate IVB dose calculation. PMID:12201413

  11. Comparison of local and regional heat transport processes into the subsurface urban heat island of Karlsruhe, Germany

    NASA Astrophysics Data System (ADS)

    Benz, Susanne; Bayer, Peter; Menberg, Kathrin; Blum, Philipp

    2014-05-01

    Temperatures in shallow urban ground are typically elevated. They manifest as subsurface urban heat islands, which are observed worldwide in different metropolitan areas and which have a site-specific areal extent and intensity. As of right now the governing heat transport processes accumulating heat in the subsurface of cities are insufficiently understood. Based on a spatial assessment of groundwater temperatures, six individual heat flux processes could be identified: (1) heat flux from elevated ground surface temperatures (GST), (2) heat flux from basements of buildings, (3) reinjection of thermal waste water, (4) sewage drains, (5) sewage leakage, and (6) district heating. In this study, the contributions of these processes are quantified on local and regional scales for the city of Karlsruhe in Germany. For the regional scale, the Regionalized Monte Carlo (RMC) method is used. This method applies a single Monte Carlo (MC) simulation for the entire study area. At relatively low data demand, the RMC method provides basic insights into the heat contribution for the entire city. For the local scale, the Local Monte Carlo (LMC) method was developed and applied. This method analyzes all dominant heat fluxes spatially dependent by performing an MC simulation for each arbitrary sized pixel of the study area (here 10 x 10 m). This more intricate approach allows for a spatial representation of all heat flux processes, which is necessary for the local planning of geothermal energy use. In order to evaluate the heat transport processes on a regional scale, we compared the mean annual thermal energies that result from the individual heat flux processes. Both methods identify the heat flux from elevated GST and the heat flux from buildings as the dominant regional processes. However, reinjection of thermal wastewater is by far the most dominant local heat flux processes with an average heat flux of 16 ± 2 W/m2 in the affected areas. Although being dominant on the regional

  12. Environmental assessment for the relocation and storage of isotopic heat sources, Hanford Site, Richland, Washington

    SciTech Connect

    1997-06-01

    As part of a bilateral agreement between the Federal Minister for Research and Technology of the Federal Republic of Germany (FRG) and the DOE, Pacific Northwest National Laboratory (PNNL) developed processes for the treatment and immobilization of high-level radioactive waste. One element of this bilateral agreement was the production of sealed isotopic heat sources. During the mid-1980s, 30 sealed isotopic heat sources were manufactured. The sources contain a total of approximately 8.3 million curies consisting predominantly of cesium-137 and strontium-90 with trace amounts of transuranic contamination. Currently, the sources are stored in A-Cell of the 324 Building. Intense radiation fields from the sources are causing the cell windows and equipment to deteriorate. Originally, it was not intended to store the isotopic heat sources for this length of time in A-cell. The 34 isotopic heat sources are classified as remote handled transuranic wastes. Thirty-one of the isotopic heat sources are sealed, and seals on the three remaining isotopic heat sources have not been verified. However, a decision has been made to place the remaining three isotopic heat sources in the CASTOR cask(s). The Washington State Department of Health (WDOH) has concurred that isotopic heat sources with verified seals or those placed into CASTOR cask(s) can be considered sealed (no potential to emit radioactive air emissions) and are exempt from WAC Chapter 246-247, Radiation Protection-Air Emissions.

  13. Mapping the Solar Wind from its Source Region into the Outer Corona

    NASA Technical Reports Server (NTRS)

    Esser, Ruth

    1997-01-01

    Knowledge of the radial variation of the plasma conditions in the coronal source region of the solar wind is essential to exploring coronal heating and solar wind acceleration mechanisms. The goal of the proposal was to determine as many plasma parameters in the solar wind acceleration region and beyond as possible by coordinating different observational techniques, such as Interplanetary Scintillation Observations, spectral line intensity observations, polarization brightness measurements and X-ray observations. The inferred plasma parameters were then used to constrain solar wind models.

  14. Welding isotopic heat sources for the cassini mission to Saturn

    SciTech Connect

    Franco-Ferreira, E.A.; George, T.G.

    1994-12-31

    In 1997 NASA will launch the Cassini scientific probe to the planet Saturn. Electric power for this probe will be provided by radioisotope thermoelecric generators thermally driven by general-purpose heat source modules. Each module contains four, 150-g pellets of {sup 238}PuO{sub 2}, individually encapsulated within a thin wall iridium-alloy shell. For the Galileo/Ulysses missions, assembly and welding took an average of 90 min per capsule. the work was done in a hot cell and the potential for personnel radiation exposure was not unduly high. The iridium alloy, from which the clad cups are made, contains a small amount of thorium to improve ductility and minimize grain growth. It has been shown that the thorium contributes to hot shortness which caused significant weld cracking during Galileo/Ulysses production. program requirements dictated that all operations provide high levels of process quality assurance. As a result, the welding system was configured to acquire copious amounts of digitized QA information. Early production operation of the welding systems has proven the ability to meet all program goals. For example, in the course of making approximately 60 girth welds during procedure qualification and safety impact testing, no rejectable weld defects have been found.

  15. A proposal for a novel H ion source based on electron cyclotron resonance heating and surface ionization

    SciTech Connect

    Tarvainen, Ollie A; Kurennoy, Sergey

    2008-01-01

    A design for a novel H{sup -} ion source based on electron cyclotron resonance plasma heating and surface ionization is presented. The plasma chamber of the source is an rf-cavity designed for TE{sub 111} eigenmode at 2.45 GHz. The desired mode is excited with a loop antenna. The ionization process takes place on a cesiated surface of a biased converter electrode. The H{sup -} ion beam is further 'self-extracted' through the plasma region. The magnetic field of the source is optimized for plasma generation by electron cyclotron resonance heating, and beam extraction. The design features of the source are discussed in detail and the attainable H{sup -} ion current, beam emittance and duty factor of the novel source are estimated.

  16. Mobile measurements of ammonia: Sources and spatial variations in the Wallis region and Zurich (Switzerland)

    NASA Astrophysics Data System (ADS)

    Elser, Miriam; El Haddad, Imad; Bruns, Emily; Pieber, Simone; Wolf, Robert; Krishna Kumar, Nivedita; Prévôt, André; Baltensperger, Urs

    2014-05-01

    Ammonia (NH3) has negative impacts on human health, climate, ecosystems and materials. Moreover, it is also an important precursor for the formation of secondary aerosols in the form of ammonium salts (ammonium nitrate, ammonium sulfate and ammonium chloride). Previous studies have shown that the vast majority of the ammonia emissions come from the agricultural sector (mostly from livestock farming and fertilizing activities). Other sources such as road transport, waste deposit, energy use and supply can also contribute to the ammonia levels in the urban areas. High concentrations of ammonia are commonly measured at the National Air Pollution Monitoring Network (NABEL) stations in Switzerland. Mobile measurements of ammonia and other pollutants (including BC, CO2, NOx and NR-PM) were conducted in the Wallis region and in Zurich in 2013 to study the spatial distribution of ammonia in Switzerland and identify its major emission sources in these regions. A new heated inlet setup was developed to improve the response time of the ammonia measurements, so that even very local sources could be identified. For both, the Wallis region and Zurich, it was observed that the background values of ammonia have a regional origin, as other pollutants affected by regional changes show similar background trends. These regional background values varied between 5 to 10 ppb during the different days of measurements. Moreover, no big differences were observed in the background values between the city center, the surrounding areas, the highway and the rural areas. The major local source of ammonia observed during these measurements was road transport, producing increases on the NH3 levels up to 4 times the background values. Based on emission factors estimated from tunnel measurements, the traffic was estimated to contribute between 20 -30% of the measured ammonia levels on a daily average in Zurich. Other sources of ammonia that can also contribute significantly to the levels of ammonia

  17. Numerical simulations of the impact of seasonal heat storage on source zone emission in a TCE contaminated aquifer

    NASA Astrophysics Data System (ADS)

    Popp, Steffi; Beyer, Christof; Dahmke, Andreas; Bauer, Sebastian

    2016-04-01

    In urban regions, with high population densities and heat demand, seasonal high temperature heat storage in the shallow subsurface represents an attractive and efficient option for a sustainable heat supply. In fact, the major fraction of energy consumed in German households is used for room heating and hot water production. Especially in urbanized areas, however, the installation of high temperature heat storage systems is currently restricted due to concerns on negative influences on groundwater quality caused e.g. by possible interactions between heat storages and subsurface contaminants, which are a common problem in the urban subsurface. Detailed studies on the overall impact of the operation of high temperature heat storages on groundwater quality are scarce. Therefore, this work investigates possible interactions between groundwater temperature changes induced by heat storage via borehole heat exchangers and subsurface contaminations by numerical scenario analysis. For the simulation of non-isothermal groundwater flow, and reactive transport processes the OpenGeoSys code is used. A 2D horizontal cross section of a shallow groundwater aquifer is assumed in the simulated scenario, consisting of a sandy sediment typical for Northern Germany. Within the aquifer a residual trichloroethene (TCE) contaminant source zone is present. Temperature changes are induced by a seasonal heat storage placed within the aquifer with scenarios of maximum temperatures of 20°C, 40°C and 60°C, respectively, during heat injection and minimum temperatures of 2°C during heat extraction. In the scenario analysis also the location of the heat storage relative to the TCE source zone and plume was modified. Simulations were performed in a homogeneous aquifer as well as in a set of heterogeneous aquifers with hydraulic conductivity as spatially correlated random fields. In both cases, results show that the temperature increase in the heat plume and the consequential reduction of water

  18. Existing climate data sources and Their Use in Heat IslandResearch

    SciTech Connect

    Akbari, Hashem; Pon, Brian; Smith, Craig Kenton; Stamper-Kurn, Dan Moses

    1998-10-01

    Existing climate data sources can be used in two general types of analysis for the detection of urban heat islands. Historical analyses use long-term data records-preferentially from several locations in and around an urban area-to trace the gradual influence of urban development on its climate. Primary sources of such data include the cooperative network, first-order National Weather Service stations, and military weather stations. Analyses of short-term data use information from a dense urban weather station network to discern the location, extent, and magnitude of urban heat islands. Such analyses may use the aforementioned national networks or regional networks such as agricultural, air quality monitoring, or utility networks. We demonstrate the use of existing data sources with a historical analysis of temperature trends in Los Angeles, California, and an analysis of short-term data of the urban temperature profile for Phoenix, Arizona. The Los Angeles climate was examined with eleven long-term data records from the cooperative network. Statistically significant trends of rising temperature were detected at Los Angeles Civic Center and other stations over some parts of the year, although timing of the increase varied from station to station. Observed increases in temperatures maybe due to long-term climate changes, microclimate influences, or local-scale heat islands. The analysis of short-term data was made for Phoenix using the PRISMS station network. Mean diurnal temperature profiles for a month were examined and compared with those for adjacent rural areas. Data fi-om stations in the center of Phoenix showed clear and significant nighttime and daytime temperature differences of 1- 2K (3 - 4"F). These temperature increases maybe attributable to a local-scale heat island.

  19. Numerical study of conductive heat losses from a magmatic source at Phlegraean Fields

    NASA Astrophysics Data System (ADS)

    Di Maio, Rosa; Piegari, Ester; Mancini, Cecilia; Scandone, R.

    2015-01-01

    The thermal evolution of the Phlegraean magmatic system (southern Italy) is studied by analyzing the influence of the thermal property variations on the solution of the heat conduction equation. The aim of this paper is to verify if appropriate choices of thermal parameters can reproduce, at least to greater depths, the high temperatures measured in the geothermal wells, drilled inside the caldera, under the assumption of heat loss from a magma chamber by conduction. Since the main purpose is to verify the plausibility of such an assumption, rather simple models of the magmatic system are adopted and only major volcanic events (i.e., the Campanian Ignimbrite and the Neapolitan Yellow Tuff eruptions) are considered. The results of the simulated two-dimensional model scenarios show that by assuming an extended source region, whose emplacement time is longer than 40 ka, heat conduction mechanisms can provide temperatures as high as those measured at depths deeper than about 2000 m. On the other hand, the 1D simulations show that appropriate choices for the thermal conductivity depth profiles can reproduce the observed temperatures at depths deeper than about 1000 m. These findings question the apparent consensus that convection is the only dominant form of heat transfer at Phlegraean Fields and might motivate new research for reconstructing the thermal evolution of the Phlegraean magmatic system.

  20. Three-dimensional magnetic field topology in a region of solar coronal heating.

    PubMed

    Solanki, S K; Lagg, A; Woch, J; Krupp, N; Collados, M

    2003-10-16

    Flares and X-ray jets on the Sun arise in active regions where magnetic flux emerges from the solar interior amd interacts with the ambient magnetic field. The interactions are believed to occur in electric current sheets separating regions of opposite magnetic polarity. The current sheets located in the corona or upper chromosphere have long been thought to act as an important source of coronal heating, requiring their location in the corona or upper chromosphere. The dynamics and energetics of these sheets are governed by a complex magnetic field structure that, until now, has been difficult to measure. Here we report the determination of the full magnetic vector in an interaction region near the base of the solar corona. The observations reveal two magnetic features that characterize young active regions on the Sun: a set of rising magnetic loops and a tangential discontinuity of the magnetic field direction, the latter being the observational signature of an electric current sheet. This provides strong support for coronal heating models based on the dissipation of magnetic energy at current sheets. PMID:14562096

  1. Organization of ice flow by localized regions of elevated geothermal heat flux

    NASA Astrophysics Data System (ADS)

    Pittard, M. L.; Galton-Fenzi, B. K.; Roberts, J. L.; Watson, C. S.

    2016-04-01

    The impact of localized regions of elevated geothermal heat flux on ice sheet dynamics is largely unknown. Simulations of ice dynamics are produced using poorly resolved and low-resolution estimates of geothermal heat flux. Observations of crustal heat production within the continental crust underneath the Lambert-Amery glacial system in East Antarctica indicate that high heat flux regions of at least 120 mW m-2 exist. Here we investigate the influence of simulated but plausible, localized regions of elevated geothermal heat flux on ice dynamics using a numerical ice sheet model of the Lambert-Amery glacial system. We find that high heat flux regions have a significant effect across areas of slow-moving ice with the influence extending both upstream and downstream of the geothermal anomaly, while fast-moving ice is relatively unaffected. Our results suggest that localized regions of elevated geothermal heat flux may play an important role in the organization of ice sheet flow.

  2. Variable Conductance Heat Pipe Cooling of Stirling Convertor and General Purpose Heat Source

    NASA Technical Reports Server (NTRS)

    Tarau, Calin; Schwendeman, Carl; Anderson, William G.; Cornell, Peggy A.; Schifer, Nicholas A.

    2013-01-01

    In a Stirling Radioisotope Power System (RPS), heat must be continuously removed from the General Purpose Heat Source (GPHS) modules to maintain the modules and surrounding insulation at acceptable temperatures. The Stirling convertor normally provides this cooling. If the Stirling convertor stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS at the cost of an early termination of the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) can be used to passively allow multiple stops and restarts of the Stirling convertor. In a previous NASA SBIR Program, Advanced Cooling Technologies, Inc. (ACT) developed a series of sodium VCHPs as backup cooling systems for Stirling RPS. The operation of these VCHPs was demonstrated using Stirling heater head simulators and GPHS simulators. In the most recent effort, a sodium VCHP with a stainless steel envelope was designed, fabricated and tested at NASA Glenn Research Center (GRC) with a Stirling convertor for two concepts; one for the Advanced Stirling Radioisotope Generator (ASRG) back up cooling system and one for the Long-lived Venus Lander thermal management system. The VCHP is designed to activate and remove heat from the stopped convertor at a 19 degC temperature increase from the nominal vapor temperature. The 19 degC temperature increase from nominal is low enough to avoid risking standard ASRG operation and spoiling of the Multi-Layer Insulation (MLI). In addition, the same backup cooling system can be applied to the Stirling convertor used for the refrigeration system of the Long-lived Venus Lander. The VCHP will allow the refrigeration system to: 1) rest during transit at a lower temperature than nominal; 2) pre-cool the modules to an even lower temperature before the entry in Venus atmosphere; 3) work at nominal temperature on Venus surface; 4) briefly stop multiple times on the Venus surface to allow scientific measurements. This paper presents the experimental

  3. ELF/VLF wave generation from the beating of two HF ionospheric heating sources

    NASA Astrophysics Data System (ADS)

    Cohen, M. B.; Moore, R. C.; Golkowski, M.; Lehtinen, N. G.

    2012-12-01

    It is well established that Extremely Low Frequency (ELF, 0.3-3 kHz) and Very Low Frequency (VLF, 3-30 kHz) radio waves can be generated via modulated High Frequency (HF, 3-10 MHz) heating of the lower ionosphere (60-100 km). The ionospheric absorption of HF power modifies the conductivity of the lower ionosphere, which in the presence of natural currents such as the auroral electrojet, creates an `antenna in the sky.' We utilize a theoretical model of the HF to ELF/VLF conversion and the ELF/VLF propagation, and calculate the amplitudes of the generated ELF/VLF waves when two HF heating waves, separated by the ELF/VLF frequency, are transmitted from two adjacent locations. The resulting ELF/VLF radiation pattern exhibits a strong directional dependence (as much as 15 dB) that depends on the physical spacing of the two HF sources. This beat wave source can produce signals 10-20 dB stronger than those generated using amplitude modulation, particularly for frequencies greater than 5-10 kHz. We evaluate recent suggestions that beating two HF waves generates ELF/VLF waves in the F-region (>150 km), and conclude that those experimental results may have misinterpreted, and can be explained strictly by the much more well established D region mechanism.

  4. Performance evaluation of ground-source heat pump system and development of suitability map for its installation

    NASA Astrophysics Data System (ADS)

    Shrestha, G.; Uchida, Y.; Yoshioka, M.; Kuronuma, S.

    2015-12-01

    Ground-source heat pump (GSHP) system is an energy efficient and environment friendly technology that uses natural subsurface heat energy stored in the shallow depth for space-heating, space-cooling, snow-melting, hot water supply etc. In Japan, development of this system is gradually increasing, however the rate is still limited due to higher initial cost caused by oversized design of ground heat exchangers. An efficient system that can lower the installation cost should be developed and evaluated for its performance in order to expand the growth of GSHP system in Japan. In addition, development of suitability map to assess appropriate locations for the system installation is essential for optimum design and sustainability. In this study, GSHP system was constructed utilizing an artesian well as ground heat exchanger (GHE) and evaluated its performance. The objective of this study is to develop low cost and high efficiency system. In areas with abundant groundwater and its flow, higher heat exchange rate can be expected leading to cost reduction and energy saving. Further, suitability map was prepared in regional scale to assess the suitable locations where this type of system can be installed. The suitability map was prepared considering local hydrogeological and thermal data. Average coefficient of performance (COP) was found to be 7 during space-cooling operation and 5 during space-heating operation. These values of COP are higher than that of normal air conditioner (air-source heat pump system).

  5. Active region emission measure distributions and implications for nanoflare heating

    SciTech Connect

    Cargill, P. J.

    2014-03-20

    The temperature dependence of the emission measure (EM) in the core of active regions coronal loops is an important diagnostic of heating processes. Observations indicate that EM(T) ∼ T{sup a} below approximately 4 MK, with 2 < a < 5. Zero-dimensional hydrodynamic simulations of nanoflare trains are used to demonstrate the dependence of a on the time between individual nanoflares (T{sub N} ) and the distribution of nanoflare energies. If T{sub N} is greater than a few thousand seconds, a < 3. For smaller values, trains of equally spaced nanoflares cannot account for the observed range of a if the distribution of nanoflare energies is either constant, randomly distributed, or a power law. Power law distributions where there is a delay between consecutive nanoflares proportional to the energy of the second nanoflare do lead to the observed range of a. However, T{sub N} must then be of the order of hundreds to no more than a few thousand seconds. If a nanoflare leads to the relaxation of a stressed coronal field to a near-potential state, the time taken to build up the required magnetic energy is thus too long to account for the EM measurements. Instead, it is suggested that a nanoflare involves the relaxation from one stressed coronal state to another, dissipating only a small fraction of the available magnetic energy. A consequence is that nanoflare energies may be smaller than previously envisioned.

  6. Harvesting Nanocatalytic Heat Localized in Nanoalloy Catalyst as a Heat Source in a Nanocomposite Thin Film Thermoelectric Device.

    PubMed

    Zhao, Wei; Shan, Shiyao; Luo, Jin; Mott, Derrick M; Maenosono, Shinya; Zhong, Chuan-Jian

    2015-10-20

    This report describes findings of an investigation of harvesting nanocatalytic heat localized in a nanoalloy catalyst layer as a heat source in a nanocomposite thin film thermoelectric device for thermoelectric energy conversion. This device couples a heterostructured copper-zinc sulfide nanocomposite for thermoelectrics and low-temperature combustion of methanol fuels over a platinum-cobalt nanoalloy catalyst for producing heat localized in the nanocatalyst layer. The possibility of tuning nanocatalytic heat in the nanocatalyst and thin film thermoelectric properties by compositions points to a promising pathway in thermoelectric energy conversion. PMID:26444621

  7. Investigation of direct expansion in ground source heat pumps

    NASA Astrophysics Data System (ADS)

    Kalman, M. D.

    A fully instrumented subscale ground coupled heat pump system was developed, and built, and used to test and obtain data on three different earth heat exchanger configurations under heating conditions (ground cooling). Various refrigerant flow control and compressor protection devices were tested for their applicability to the direct expansion system. Undistributed Earth temperature data were acquired at various depths. The problem of oil return at low evaporator temperatures and low refrigerant velocities was addressed. An analysis was performed to theoretically determine what evaporator temperature can be expected with an isolated ground pipe configuration with given length, pipe size, soil conditions and constant heat load. Technical accomplishments to data are summarized.

  8. An MHD heat source based on intermetallic reactions

    SciTech Connect

    Sadjian, H.; Zavitsanos, P. ); Marston, C.H. )

    1991-05-06

    The main objective of this program was the development of an MHD heat source of potential use in Space - Based Multi Megawatt, MHD Power Systems. The approach is based on extension of high temperature chemical/ion release technology developed by the General Sciences, Incorporated (GSI) team and successfully applied in other Space Applications. Solid state reactions have been identified which can deliver energy densities and electrons in excess of those from high energy explosives as well as other conventional fuels. The use of intermetallic reactions can be used to generate hot hydrogen plasma from the reaction, to create a high level of seedant ionization, can be packaged as a cartridge type fuels for discrete pulses. The estimated weight for energizing a (100 MW - 1000 sec) Pulsed MHD Power System can range from 12 to 25 {times} 10{sup 3} kg depending on reaction system and strength of the magnetic field. The program consisted of two major tasks with eight subtasks designed to systematically evaluate these concepts in order to reduce fuel weight requirements. Laboratory measurements on energy release, reaction product identification and levels of ionization were conducted in the first task to screen candidate fuels. The second task addressed the development of a reaction chamber in which conductivity, temperature and pressure were measured. Instrumentation was developed to measure these parameters under high temperature pulsed conditions in addition to computer programs to reduce the raw data. Measurements were conducted at GSI laboratories for fuel weights of up to 120 grams and at the Franklin Research Center* for fuel weights up to 1 kilogram. The results indicate that fuel weight can be scaled using modular packaging. Estimates are presented for fuel weight requirements. 15 refs.

  9. Steady temperature and density distributions in a gas containing heat sources

    NASA Technical Reports Server (NTRS)

    Davison, H. W.

    1971-01-01

    Computer program, STADDIG, is based on steady state, one dimensional heat transfer calculation using cylindrical coordinates. Program allows for conduction across gas and container walls. Heat is dissipated from walls by forced convection cooling with incompressible coolant. Heat sources are included in coolant, gas, and walls.

  10. Source-rock distribution model of the periadriatic region

    SciTech Connect

    Zappaterra, E. )

    1994-03-01

    The Periadriatic area is a mosaic of geological provinces comprised of spatially and temporally similar tectonic-sedimentary cycles. Tectonic evolution progressed from a Triassic-Early Jurassic (Liassic) continental rifting stage on the northern edge of the African craton, through an Early Jurassic (Middle Liassic)-Late Cretaceous/Eocene oceanic rifting stage and passive margin formation, to a final continental collision and active margin deformation stage in the Late Cretaceous/Eocene to Holocene. Extensive shallow-water carbonate platform deposits covered large parts of the Periadriatic region in the Late Triassic. Platform breakup and development of a platform-to-basin carbonate shelf morphology began in the Late Triassic and extended through the Cretaceous. On the basis of this paleogeographic evolution, the regional geology of the Periadriatic region can be expressed in terms of three main Upper Triassic-Paleogene sedimentary sequences: (A), the platform sequence; (B), the platform to basin sequence; and (C), the basin sequence. These sequences developed during the initial rifting and subsequent passive-margin formation tectonic stages. The principal Triassic source basins and most of the surface hydrocarbon indications and economically important oil fields of the Periadriatic region are associated with sequence B areas. No major hydrocarbon accumulations can be directly attributed to the Jurassic-Cretaceous epioceanic and intraplatform source rock sequences. The third episode of source bed deposition characterizes the final active margin deformation stage and is represented by Upper Tertiary organic-rich terrigenous units, mostly gas-prone. These are essentially associated with turbiditic and flysch sequences of foredeep basins and have generated the greater part of the commercial biogenic gases of the Periadriatic region. 82 refs., 11 figs., 2 tabs.

  11. Measured Performance of a Low Temperature Air Source Heat Pump

    SciTech Connect

    Johnson, R. K.

    2013-09-01

    A 4-ton Low Temperature Heat Pump (LTHP) manufactured by Hallowell International was installed in a residence near New Haven, Connecticut and monitored over two winters of operation. After attending to some significant service issues, the heat pump operated as designed. This report should be considered a review of the dual compressor 'boosted heat pump' technology. The Low Temperature Heat Pumpsystem operates with four increasing levels of capacity (heat output) as the outdoor temperature drops. The system was shown to select capacity correctly, supplying the appropriate amount of heat to the house across the full range of outdoor temperatures. The system's Coefficient of Performance (Seasonal COP, or SCOP) over two entire winters was calculated, based on measured data, to be 3.29over the first winter and 2.68 over the second winter. A second seasonal efficiency calculation by a different method yielded a SCOP of 2.78 for the first winter and 2.83 for the second winter. This second seasonal efficiency calculation was determined by comparing measured heat pump energy use to the in situ energy use with resistance heat alone. This method is the ratio of the slopes of thedaily energy use load lines.

  12. THEMIS Observations of the Magnetopause Electron Diffusion Region: Large Amplitude Waves and Heated Electrons

    NASA Technical Reports Server (NTRS)

    Tang, Xiangwei; Cattell, Cynthia; Dombeck, John; Dai, Lei; Wilson, Lynn B. III; Breneman, Aaron; Hupack, Adam

    2013-01-01

    We present the first observations of large amplitude waves in a well-defined electron diffusion region based on the criteria described by Scudder et al at the subsolar magnetopause using data from one Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellite. These waves identified as whistler mode waves, electrostatic solitary waves, lower hybrid waves, and electrostatic electron cyclotron waves, are observed in the same 12 s waveform capture and in association with signatures of active magnetic reconnection. The large amplitude waves in the electron diffusion region are coincident with abrupt increases in electron parallel temperature suggesting strong wave heating. The whistler mode waves, which are at the electron scale and which enable us to probe electron dynamics in the diffusion region were analyzed in detail. The energetic electrons (approx. 30 keV) within the electron diffusion region have anisotropic distributions with T(sub e(right angle))/T(sub e(parallel)) > 1 that may provide the free energy for the whistler mode waves. The energetic anisotropic electrons may be produced during the reconnection process. The whistler mode waves propagate away from the center of the "X-line" along magnetic field lines, suggesting that the electron diffusion region is a possible source region of the whistler mode waves.

  13. Linear ion source with closed drift and extended acceleration region

    SciTech Connect

    Park, Dong-Hee; Kim, Ji-Hwan; Ermakov, Yury; Choi, Won-Kook

    2008-02-15

    Ion source with closed drift, which is caused by ExB field, and extended acceleration region is discussed. Though conventional circular-type closed drift ion source has advantages of high efficiency of gas ionization and low ion beam energy, there is a limitation in enlarging the beam size. Linear ion source with horse-track shape with 270 mm ceramic channel width is newly designed and tested. Inert gas (Ar) and reactive gas (O{sub 2}) are discharged. Discharge is ignited with voltage of 90 V. Discharge current is proportional to discharge voltage and increases up to 16.3 A in argon and 15.6 A in oxygen at discharge voltage of 320 V. Extracted ion beam current is also proportional to discharge voltage and is saturated after 280 V for both gases. It is measured up to 0.78 mA/cm{sup 2} in argon beam and 0.73 mA/cm{sup 2} in oxygen beam at a distance of 100 mm from the ion source. Argon ion beam shows better space uniformity than oxygen across the beam extraction region.

  14. Source regions of stratospheric VSLS in the Indian Ocean

    NASA Astrophysics Data System (ADS)

    Quack, Birgit; Hepach, Helmke; Atlas, Elliot; Bracher, Astrid; Endres, Sonja; Arevalo-Martinez, Damian; Bange, Hermann; Lennartz, Sinikka; Steinhoff, Tobias; Booge, Dennis; Zarvasky, Alexander; Marandino, Christa; Patey, Matt; Achterberg, Eric; Dengler, Markus; Fiehn, Alina; Tegtmeier, Susann; Krüger, Kirstin

    2016-04-01

    Halogenated very-short-lived substances (VSLS), which are naturally produced in the ocean, play a significant role in present day ozone depletion, in particular in combination with enhanced stratospheric sulfate aerosol, which is also partly derived from oceanic VSLS. The decline of anthropogenic chlorine in the stratosphere within the 21st century will increase the relative importance of the natural emissions on stratospheric ozone destruction. Especially, oceanic sources and source regions of the compounds need to be better constrained, in order to improve the future prediction. During boreal summer the Asian monsoon circulation transports air masses from the Indian Ocean to the stratosphere, while the contribution of VSLS from this ocean to stratospheric halogen and sulfur is unknown. During the research cruises SO 234/2 and SO 235 in July-August 2014 onboard RV SONNE oceanic and atmospheric halogenated VSLS such as bromoform (CHBr3), dibromomethane (CH2Br2) and methyl iodide (CH3I) were measured in the subtropical and tropical West Indian Ocean for the first time. Here we present the oceanic sources of the halogenated compounds and their relation to other biogeochemical parameters (short- and longlived trace gases, phytoplankton and nutrients) along the cruise track, which covered coastal, upwelling and open ocean regimes and the Seychelles-Chagos thermocline ridge as important source region for stratospheric bromine.

  15. Designing, selecting and installing a residential ground-source heat pump system

    SciTech Connect

    Hughes, Patrick; Liu, Xiaobing; Munk, Jeffrey D

    2010-01-01

    It's a compelling proposition: Use the near-constant-temperature heat underground to heat and cool your home and heat domestic water, slashing your energy bills. Yet despite studies demonstrating significant energy savings from ground-source heat pump (GSHP) systems, their adoption has been hindered by high upfront costs. Fewer than 1% of US homes use a GSHP system. However, compared to a minimum-code-compliant conventional space-conditioning system, when properly designed and installed, a GSHP retrofit at current market prices offers simple payback of 4.3 years on national average, considering existing federal tax credits. Most people understand how air-source heat pumps work: they move heat from indoor air to outdoor air when cooling and from outdoor air to indoor air when heating. The ground-source heat pump operates on the same principle, except that it moves heat to or from the ground source instead of outdoor air. The ground source is usually a vertical or horiontal ground heat exchanger. Because the ground usually has a more favorable temperature than ambient air for the heating and cooling operation of the vapor-compression refrigeration cycle, GSHP sysems can operate with much higher energy efficiencies than air-source heat pump systems when properly designed and installed. A GSHP system used in a residual building typically provides space conditioning and hot water and comprises three major components: a water-source heat pump unit designed to operate at a wider range of entering fluid temperatures (typically from 30 F to 110 F, or 1 C to 43 C) than a conventional water-source heat pump unit; a ground heat exchanger (GHX); and distribution systems to deliver hot water to the storage tank and heating or cooling to the conditioned rooms. In most residual GSHP systems, the circulation pumps and associated valves are integrated with the heat pump to circulate the heat-carrier fluid (water or aqueous antifreeze solution) through the heat pump and the GHX. A

  16. Possibilities of utilizing alternative energy sources for combined heat supply systems in the Baltic

    SciTech Connect

    Shipkovs, P.; Grislis, V.; Zebergs, V. )

    1991-01-01

    The problem of alternative energy sources is an issue of major importance for the Baltic republics because of the limited supply of conventional energy resources. One of the ways to solve this problem could be the introduction of combined heat supply systems (CHSS). The combined heat supply systems are such systems where various energy sources in different regimes are made use of to ensure the optimum temperature on residential and industrial premises. The influence of climatic conditions on the selection of heat supply systems has been studied at large. In the present paper the use of alternative energy sources (AES) in combined heat supply systems (CHSS) is described.

  17. A capital cost comparison of commercial ground-source heat pump systems

    SciTech Connect

    Rafferty, K.

    1995-02-01

    In the March 1994 issue of the Quarterly Bulletin, a Geo-Heat Center Research Project involving ground-source heat pumps (GSHP) systems for commercial buildings was introduced. This project which evaluated the capital costs associated with three different ground-source designs was completed in June 1994. As a result of this work, a final report {open_quotes}A Capital Cost Comparison of Commercial Ground-Source Heat Pump Systems{close_quotes} was issued. This article is a summary of that report. The full report is available from the Geo-Heat Center.

  18. Temperature and Humidity Independent Control Research on Ground Source Heat Pump Air Conditioning System

    NASA Astrophysics Data System (ADS)

    Chen, G.; Wang, L. L.

    Taking green demonstration center building air conditioning system as an example, this paper presents the temperature and humidity independent control system combined with ground source heat pump system, emphasis on the design of dry terminal device system, fresh air system and ground source heat pump system.

  19. Heat source for an amagmatic hydrothermal system, Noto Peninsula, Central Japan

    NASA Astrophysics Data System (ADS)

    Umeda, Koji; Ninomiya, Atusi; Negi, Tateyuki

    2009-01-01

    Although there is no evidence of volcanism in the Noto Peninsula since the late Miocene, the peninsula has long been known to be unusual and atypical of non-volcanic regions, as indicated by high-temperature hot springs and a geothermal gradient greater than 50 K/km. In order to provide geochemical constraints on the heat source for amagmatic hydrothermal activity, the chemical and isotopic compositions of 14 gas and water samples from hot springs were measured. The observed 3He/4He ratios of most hot spring gases range from 0.03 to 1.2 RA (RA denotes the atmospheric 3He/4He ratio of 1.4 × 10-6). In these samples, mantle helium composes less than 10% of the total helium, indicating an insignificant contribution of mantle-derived volatiles from, for example, newly ascending magma and/or aqueous fluid generated by dehydration of the subducting slab. The Noto Peninsula mainly consists of Neogene volcaniclastic and sedimentary rocks overlying Paleozoic to Mesozoic basement rocks associated with uranium-bearing granite pegmatite containing elevated concentrations of heat generating elements such as uranium, thorium, and potassium. A plausible heat source for the amagmatic hydrothermal activity can be attributed to this distinctive geological environment where high heat producing granitic rocks are buried under Neogene sedimentary rocks with low thermal conductivities that act as thermal blankets. Most Noto Peninsula hot springs are found in areas of active faulting, where stress concentrations since the late Miocene could open an existing fault pathway because the fluid pressure is close to the lithostatic pressure. Meteoric waters circulating through hot basement rock come to the surface along these permeable conduits with minimal mixing with shallow groundwater, resulting in emanation of high-temperature hot springs with low 3He/4He ratio gases along active fault zones.

  20. Influence of water grid on combustion process in small dendromass heat source

    NASA Astrophysics Data System (ADS)

    Papučík, Štefan; Pilát, Peter; Hrabovský, Peter; Patsch, Marek

    2016-06-01

    For achieving of low emission in compliance of required performance parameters of small heat source affects a number of factors. It's not just about redistribution and intensity of combustion air or flue gas temperature in the chimney. An important role in the combustion process also have a combustion chamber shape, size of embers, placing of the fuel in the chamber, positioning, distribution and temperature of combustion air entering into the combustion process, the tightness of the measured heat source or temperature of the combustion chamber. The bigger problem with the achievement of low emission limits occurs at the operation of gasification heat source in lower performance. The article discusses about the effects on the combustion process is simple structural adjustment of heat source - removal of water grate during operation at reduced performance. On measuring were used identical small heat sources (with and without lambda probe oxygen sensor, with water and without water grate), which uses principle of biomass gasification.

  1. Optimum load distribution between heat sources based on the Cournot model

    NASA Astrophysics Data System (ADS)

    Penkovskii, A. V.; Stennikov, V. A.; Khamisov, O. V.

    2015-08-01

    One of the widespread models of the heat supply of consumers, which is represented in the "Single buyer" format, is considered. The methodological base proposed for its description and investigation presents the use of principles of the theory of games, basic propositions of microeconomics, and models and methods of the theory of hydraulic circuits. The original mathematical model of the heat supply system operating under conditions of the "Single buyer" organizational structure provides the derivation of a solution satisfying the market Nash equilibrium. The distinctive feature of the developed mathematical model is that, along with problems solved traditionally within the bounds of bilateral relations of heat energy sources-heat consumer, it considers a network component with its inherent physicotechnical properties of the heat network and business factors connected with costs of the production and transportation of heat energy. This approach gives the possibility to determine optimum levels of load of heat energy sources. These levels provide the given heat energy demand of consumers subject to the maximum profit earning of heat energy sources and the fulfillment of conditions for formation of minimum heat network costs for a specified time. The practical realization of the search of market equilibrium is considered by the example of a heat supply system with two heat energy sources operating on integrated heat networks. The mathematical approach to the solution search is represented in the graphical form and illustrates computations based on the stepwise iteration procedure for optimization of levels of loading of heat energy sources (groping procedure by Cournot) with the corresponding computation of the heat energy price for consumers.

  2. Sources and contributions of wood smoke during winter in London: assessing local and regional influences

    NASA Astrophysics Data System (ADS)

    Crilley, L. R.; Bloss, W. J.; Yin, J.; Beddows, D. C. S.; Harrison, R. M.; Allan, J. D.; Young, D. E.; Flynn, M.; Williams, P.; Zotter, P.; Prevot, A. S. H.; Heal, M. R.; Barlow, J. F.; Halios, C. H.; Lee, J. D.; Szidat, S.; Mohr, C.

    2014-10-01

    Determining the contribution of wood smoke to air pollution in large cities such as London is becoming increasingly important due to the changing nature of domestic heating in urban areas. During winter, biomass burning emissions can exceed the contributions from traffic emissions, and have been identified as a major cause of exceedences of European air quality limits. The aim of this work was to quantify the contribution of biomass burning in London to concentrations of PM2.5 and determine whether local emissions or regional contributions were the main source of biomass smoke. To achieve this, a number of biomass burning chemical tracers were analysed at a site within central London and two sites in surrounding rural areas. Concentrations of levoglucosan, elemental carbon (EC), organic carbon (OC) and K+ were generally well correlated across the three sites. At all the sites, biomass burning was found to be a source of OC and EC, with the largest contribution of EC from traffic emissions, while for OC the dominant fraction likely included contributions from secondary organic aerosols, primary biogenic and cooking sources. Source apportionment of the EC and OC using average source ratios from published data was found to give reasonable estimation of the total carbon from non-fossil and fossil fuel sources based upon comparison with estimates derived from 14C analysis. Black carbon (BC) data from 2 and 7 wavelength Aethalometers were also apportioned into the contributions from biomass burning and traffic, based upon the enhanced absorption of wood smoke at UV wavelengths compared to BC. While the source apportionment of BC using this approach found similar trends to that observed for EC, higher percentage contributions of wood burning to BC were estimated. Based on a wood smoke mass conversion factor for levoglucosan, mean wood smoke mass at the sites was found to range from 0.78-1.0 μg m-3 during the campaign in January-February 2012. Measurements on a 160 m

  3. Short-Term Energy Outlook Model Documentation: Regional Residential Heating Oil Price Model

    EIA Publications

    2009-01-01

    The regional residential heating oil price module of the Short-Term Energy Outlook (STEO) model is designed to provide residential retail price forecasts for the 4 census regions: Northeast, South, Midwest, and West.

  4. Recent Research in Compression Refrigeration Cycle Air Source Heat Pumps.

    NASA Astrophysics Data System (ADS)

    Arai, Akira; Senshu, Takao

    The most important theme for heat pump air conditioners is the improvement of energy saving and comfort. Recently, cycle components, especially compressores and heat exchangers have been improved greatly in their performance and efficiency. As for compressors, large progress in their efficiencies have been made by detailed analysises such as mechanical losses and by the development of a new type compression mechanism. As for heat exchangers, various high heat transfer surfaces have been developed together with the improvement of the production technologies for them. Further, the effect of the capacity-modulated cycle is evaluated quantitatively through the improvements of static and transient cycle simulation technologies. And in order to realize this cffect, the electrically driven expansion valves heve been marketed. This review introduces the trends of these energy-saving technologies as well as comfort improvement studies.

  5. Potential source regions of dust accumulated in northern Africa

    NASA Astrophysics Data System (ADS)

    Wasowska, S.; Woronko, B.

    2012-04-01

    Iguidi and Chech-Adrar, although the most probable source area is Erg Occidental. Tunisian dusts come from vast expanses of Erg Oriental and Chott-el-Jerid. The potential source of the dusts accumulated in Alexandria could be Libyan Desert. This does not preclude also much more distant sources of sediment, as for instance ergs from North Sudan. From the other hand the presence of shell parts of diatoms of the Actinoptychus genus may indicate the dispelling of the Nile alluvium. Key words: source region, aeolian accumulation, north Africa, textural features of grains, aeolian dust, meteorological situation, Sahara, SEM analysis

  6. Atmospheric Pollution and Emission Sources in South Asian Urban Region

    NASA Astrophysics Data System (ADS)

    Biswas, K. F.; Husain, Liaquat

    2009-04-01

    Rapid urbanization, and lack of efficient monitoring and control of pollution, along with phenomena like Asian Brown Haze or prolonged episodes of winter fog, makes the South Asian atmospheric chemistry a very complex one. The anthropogenic aerosols released from this region are projected to become the dominant component of anthropogenic aerosols worldwide in the next 25 years (Nakicenovic and Swart, 2000). The region is one of the most densely populated in the world, with present population densities of 100-500 persons km-2. There are six big cities, namely, Delhi, Dhaka, Karachi, Kolkata, Lahore, and Mumbai, each housing a population around or above 10 million. There is now a real concern about the sustainability of the region's ability to support the population due to air pollution, loss of biodiversity and soil degradation. Therefore, we conducted several extensive campaigns over last 10 years in Lahore, Karachi, and Islamabad in Pakistan to (1) chemically characterize the aerosols (PM2.5 mass, concentrations of trace elements, ions, black and organic carbon), and gaseous pollutants (concentrations of NH3, SO2, HONO, HNO3, HCl and (COOH)2, and (2) identify the major emission sources in this region. Exceedingly high concentrations of all species, relative to major urban areas of US and Europe, were observed. Concentrations of PM2.5, BC, Pb, SO42-, NH4+, HONO, NH3 respectively, up to 476, 110, 12, 66, 60, 19.6 and 50 μgm-3 were observed in these cities, which were far in excess of WHO and US EPA air quality standard (Biswas et al., 2008). We use air parcel back trajectories, intercomponent relationships and meteorological observations to explain chemistry and emission sources of aerosol constituents. Carbonaceous aerosols contributed up to 69% of the PM2.5 mass (Husain et al., 2007). Source apportionment was conducted using positive matrix factorization. The analysis has classified six emission sources of aerosol components, namely, industrial activities, wood

  7. Anthropogenic carbon dioxide source regions observed from space

    NASA Astrophysics Data System (ADS)

    Schneising, Oliver; Heymann, Jens; Buchwitz, Michael; Reuter, Maximilian; Bovensmann, Heinrich; Burrows, John P.

    2013-04-01

    Urban areas, which are home to the majority of today's world population, are responsible for more than two-thirds of the global energy-related carbon dioxide emissions. Given the ongoing demographic growth and rising energy consumption in metropolitan regions particularly in the developing world, urban-based emissions are expected to further increase in the future. As a consequence, monitoring and independent verification of reported anthropogenic emissions is becoming more and more important. It is demonstrated using CO2 column-averaged mole fraction data retrieved from the SCIAMACHY instrument onboard ENVISAT that anthropogenic CO2 emissions can be detected from space and that emission trends might be tracked using satellite observations. This is promising with regard to future satellite missions with high spatial resolution and wide swath imaging capability aiming at constraining anthropogenic emissions down to the point-source scale. By subtracting retrieved background values from those retrieved over urban areas the regional contrasts are quantified and significant CO2 enhancements are found for several anthropogenic source regions around the world. The order of magnitude of the enhancements is in agreement with what is expected for anthropogenic CO2 signals. The validity of the retrieved spatial enhancement patterns and of the temporal trends of the retrieved enhancements is assessed by comparison with anthropogenic emissions from the Emission Database for Global Atmospheric Research (EDGAR).

  8. AERONET - Aerosol Climatology From Megalopolis Aerosol Source Regions

    NASA Astrophysics Data System (ADS)

    Holben, B. N.; Eck, T. F.; Dubovik, O.; Smirnov, A.; Slutsker, I.; Artaxo, P.; Leyva, A.; Lu, D.; Sano, I.; Singh, R. P.; Quel, E.; Tanre, D.; Zibordi, G.

    2002-05-01

    AERONET is a globally distributed network of ~170 identical sun and sky scanning spectral radiometers expanded by federation with collaborating investigators that contribute to the AERONET public domain data-base. We will detail the current distribution and plans for expanded collaboration. Recent products available through the project database are important for assessment of human health as well as climate forcing issues. We will illustrate a summary of aerosol optical properties measured in Indian, East Asian, North American, South American and European megalopolis source regions. We will present monthly mean fine and coarse particle aerosol optical depth, particle size distributions and single scattering albedos. Each region represents a population in excess of 10 million inhabitants within a 200 km radius of the observation site that dictate the anthropogenic aerosol sources contributing to significantly diverse aerosol properties as a function of economic development and seasonally dependent meteorological processes. The diversity of the measured optical properties of urban aerosols illustrates the need for long-term regional monitoring that contribute to comparative assessments for health and climate change investigations.

  9. Heat flow and hot dry rock geothermal resources of the Clearlake Region, northern California

    SciTech Connect

    Burns, K.L.

    1996-08-01

    The Geysers-Clear Lake geothermal anomaly is an area of high heat flow in northern California. The anomaly is caused by abnormally high heat flows generated by asthenospheric uplift and basaltic magmatic underplating at a slabless window created by passage of the Mendocino Triple Junction. The Clear Lake volcanic field is underlain by magmatic igneous bodies in the form of a stack of sill-form intrusions with silicic bodies generally at the top and basic magmas at the bottom. The tabular shape and wide areal extent of the heat sources results in linear temperature gradients and near-horizontal isotherms in a broad region at the center of the geothermal anomaly. The Hot Dry Rock (HDR) portion of The Geysers-Clear Lake geothermal field is that part of the geothermal anomaly that is external to the steamfield, bounded by geothermal gradients of 167 mW/m2 (4 heat flow units-hfu) and 335 mW/m2 (8 hfu). The HDR resources, to a depth of 5 km, were estimated by piece-wise linear summation based on a sketch map of the heat flow. Approximately, the geothermal {open_quotes}accessible resource base{close_quotes} (Qa) is 1.68E+21 J; the {open_quotes}HDR resource base{close_quotes} (Qha) is 1.39E+21 J; and the {open_quotes}HDR power production resource{close_quotes} (Qhp) is 1.01E+21 J. The HDR power production resource (Qhp) is equivalent to 2.78E+ 11 Mwht (megawatt hours thermal), or 1.72E+11 bbls of oil.

  10. Flow Characteristics of the Raw Sewage for the Design of Sewage-Source Heat Pump Systems

    PubMed Central

    Xu, Ying; Wu, Yuebin; Sun, Qiang

    2014-01-01

    The flow characteristics of raw sewage directly affect the technical and economic performance of sewage-source heat pump systems. The purpose of this research is to characterize the flow characteristics of sewage by experimental means. A sophisticated and flexible experimental apparatus was designed and constructed. Then the flow characteristics of the raw sewage were studied through laboratorial testing and theoretical analyses. Results indicated that raw sewage could be characterized as a power-law fluid with the rheological exponent n being 0.891 and the rheological coefficient k being 0.00175. In addition, the frictional loss factor formula in laminar flow for raw sewage was deduced by theoretical analysis of the power-law fluid. Furthermore, an explicit empirical formula for the frictional loss factor in turbulent flow was obtained through curve fitting of the experimental data. Finally, the equivalent viscosity of the raw sewage is defined in order to calculate the Reynolds number in turbulent flow regions; it was found that sewage had two to three times the viscosity of water at the same temperature. These results contributed to appropriate parameters of fluid properties when designing and operating sewage-source heat pump systems. PMID:24987735

  11. Seismic source-region elastic calculations on KDYNA

    SciTech Connect

    Clarke, D.B.

    1994-03-01

    This paper summarizes the results of source-region simulations on the KDYNA hydrodynamics code. The source was a pressure-step function in a 40-m-radius cavity 500 m below a free surface. The problem of a driven cavity in an elastic material was chosen as a test and calibration problem for two reasons. First, the driven cavity is a model for an underground explosion. Secondly, the availability of analytical methods for waves in elastic solids means that alternate calculational paths exist for calculating the distant signals from the cavity. Data from an array of sensor points roughly 1 km from the source were saved and passed to Howard Patton and Keith K. Nakanish for input to a NMTS (Normal Mode Time Series) code. The data consisted of the time histories (0 to 2 s) of the radial and axial velocities and the radial, axial, and shear components of the stress at each sensor point. The NMTS code will use the input to predict the signals in the far field (e.g., 300 km) from the explosion source. This elastic KDYNA calculation provides a complete and satisfactory simulation for input to the NMTS code and for comparison with other calculational methods.

  12. Simulation studies on multi-mode heat transfer from an open cavity with a flush-mounted discrete heat source

    NASA Astrophysics Data System (ADS)

    Gururaja Rao, C.; Nagabhushana Rao, V.; Krishna Das, C.

    2008-04-01

    Prominent results of a simulation study on conjugate convection with surface radiation from an open cavity with a traversable flush mounted discrete heat source in the left wall are presented in this paper. The open cavity is considered to be of fixed height but with varying spacing between the legs. The position of the heat source is varied along the left leg of the cavity. The governing equations for temperature distribution along the cavity are obtained by making energy balance between heat generated, conducted, convected and radiated. Radiation terms are tackled using radiosity-irradiation formulation, while the view factors, therein, are evaluated using the crossed-string method of Hottel. The resulting non-linear partial differential equations are converted into algebraic form using finite difference formulation and are subsequently solved by Gauss Seidel iterative technique. An optimum grid system comprising 111 grids along the legs of the cavity, with 30 grids in the heat source and 31 grids across the cavity has been used. The effects of various parameters, such as surface emissivity, convection heat transfer coefficient, aspect ratio and thermal conductivity on the important results, including local temperature distribution along the cavity, peak temperature in the left and right legs of the cavity and relative contributions of convection and radiation to heat dissipation in the cavity, are studied in great detail.

  13. Millimeter waves as a source of selective heating of skin.

    PubMed

    Zhadobov, Maxim; Alekseev, Stanislav I; Le Dréan, Yves; Sauleau, Ronan; Fesenko, Evgeny E

    2015-09-01

    This study demonstrates that 20-100 GHz range can be used for spatially-accurate focusing of heating inside the skin achieved by varying frequency and exposure beam size, as well as by enforcing air convection. The latter is also used to reduce overheating of skin surface. Heating at different skin depths depending on these parameters is investigated in detail using the hybrid bio-heat equation. In particular, it is shown that decreasing frequency and/or increasing exposure beam size at forced airflow result in elevation of heating of deeper layers of tissue and decrease of skin surface temperature. Changes of water content within 15%, which exceed those due to aging and presence of tumors, only slightly affect heating. Exposure intensity necessary to reach a target temperature significantly increases in different areas of body with elevated blood flow. Dependence on exposure intensity and hyperthermia treatment duration is also investigated and discussed. Results of this study suggest that the lower part of the millimeter-wave range is an attractive alternative for non-invasive thermal treatment of skin cancer with a high spatial resolution. PMID:26179286

  14. Design of a nuclear isotope heat source assembly for a spaceborne mini-Brayton power module.

    NASA Technical Reports Server (NTRS)

    Wein, D.; Gorland, S. H.

    1973-01-01

    Results of a study to develop a feasible design definition of a heat source assembly (HSA) for use in nominal 500-, 1200-, or 2000-W(e) mini-Brayton spacecraft power systems. The HSA is a modular design which is used either as a single unit to provide thermal energy to the 500-W(e) mini-Brayton power module or in parallel with one or two additional HSAs for the 1200- or 2000-W(e) power module systems. Principal components consist of a multihundred watt RTG isotope heat source, a heat source heat exchanger which transfers the thermal energy from the heat source to the mini-Brayton power conversion system, an auxiliary cooling system which provides requisite cooling during nonoperation of the power conversion module and an emergency cooling system which precludes accidental release of isotope fuel in the event of system failure.

  15. Regional Moment Tensor Inversion for Source Type Identification

    NASA Astrophysics Data System (ADS)

    Dreger, D. S.; Ford, S. R.; Walter, W. R.

    2008-12-01

    With Green's functions from calibrated seismic velocity models it is possible to use regional distance moment tensor inversion for source-type identification. The deviatoric and isotropic source components for 17 explosions at the Nevada Test Site, as well as 12 earthquakes and 3 collapses in the surrounding region of the western US, are calculated using a regional time-domain full waveform inversion for the complete moment tensor. The events separate into specific populations according to their deviation from a pure double-couple and ratio of isotropic to deviatoric energy. The separation allows for anomalous event identification and discrimination between explosions, earthquakes, and collapses. Confidence regions of the model parameters are estimated from the data misfit by assuming normally distributed parameter values. We investigate the sensitivity of the resolved parameters of an explosion to imperfect Earth models, inaccurate event depths, and data with a low signal-to-noise ratio (SNR) assuming a reasonable azimuthal distribution of stations. In the band of interest (0.02-0.10 Hz) the source-type calculated from complete moment tensor inversion is insensitive to velocity models perturbations that cause less than a half-cycle shift (<5 sec) in arrival time error if shifting of the waveforms is allowed. The explosion source-type is insensitive to an incorrect depth assumption (for a true depth of 1 km), and the goodness-of-fit of the inversion result cannot be used to resolve the true depth of the explosion. Noise degrades the explosive character of the result, and a good fit and accurate result are obtained when the signal-to-noise ratio (SNR) is greater than 5. We assess the depth and frequency dependence upon the resolved explosive moment. As the depth decreases from 1 km to 200 m, the isotropic moment is no longer accurately resolved and is in error between 50-200%. However, even at the most shallow depth the resultant moment tensor is dominated by the

  16. Evaluation of water source heat pumps for the Juneau, Alaska Area

    SciTech Connect

    Jacobsen, J.J.; King, J.C.; Eisenhauer, J.L.; Gibson, C.I.

    1980-07-01

    The purposes of this project were to evaluate the technical and economic feasibility of water source heat pumps (WSHP) for use in Juneau, Alaska and to identify potential demonstration projects to verify their feasibility. Information is included on the design, cost, and availability of heat pumps, possible use of seawater as a heat source, heating costs with WSHP and conventional space heating systems, and life cycle costs for WSHP-based heating systems. The results showed that WSHP's are technically viable in the Juneau area, proper installation and maintenance is imperative to prevent equipment failures, use of WSHP would save fuel oil but increase electric power consumption. Life cycle costs for WSHP's are about 8% above that for electric resistance heating systems, and a field demonstration program to verify these results should be conducted. (LCL)

  17. Regional Seismic Identification Research:Processing, Transportability and Source Models

    SciTech Connect

    Walter, W; Mayeda, K; Rodgers, A; Taylor, S; Dodge, D; Matzel, E; Ganzberger, M

    2004-07-09

    Our identification research for the past several years has focused on the problem of correctly discriminating small-magnitude explosions from a background of earthquakes, mining tremors, and other events. Small magnitudes lead to an emphasis on regional waveforms. It has been shown that at each test site where earthquake and explosions are in close proximity and recorded at the same station, clear differences in the regional body waves such as the relative high frequency amplitudes of P and S waves can be used to discriminate between event types. However path and source effects can also induce such differences, therefore these must be quantified and accounted for. We have been using a specific technique called Magnitude and Distance Amplitude Correction (MDAC), with some success to account for some of these effects.

  18. Forced-convection Heat Transfer to Water at High Pressures and Temperatures in the Nonboiling Region

    NASA Technical Reports Server (NTRS)

    Kaufman, S J; Henderson, R W

    1951-01-01

    Forced-convection heat-transfer data have been obtained for water flowing in an electrically heated tube of circular cross section at water pressures of 200 and 2000 pounds per square inch, and temperatures in the nonboiling region, for water velocities ranging between 5 and 25 feet per second. The results indicate that conventional correlations can be used to predict heat-transfer coefficients for water at pressures up to 2000 pounds per square inch and temperatures in the nonboiling region.

  19. Investigation of heat pump efficiencies using groundwater and/or ground coil in the Gulf Coast region. Final report

    SciTech Connect

    Mei, H.T.

    1982-08-01

    This project examines the energy efficiencies of five different water source heat pump systems. This is further supported by an experimental effort in which an existing residence is retrofitted with a heat pump and other energy sources: well water as a heat source/sink, vertical geothermal well as heat source/heat sink/storage, horizontal buried metal and plastic ground coils to use as heat source/heat sink, and a solar assist system. The energy elements are operated individually and in combination configurations to determine performance, and cost effectiveness of the energy alternatives are explored.

  20. Numerical study of plasma generation process and internal antenna heat loadings in J-PARC RF negative ion source.

    PubMed

    Shibata, T; Nishida, K; Mochizuki, S; Mattei, S; Lettry, J; Hatayama, A; Ueno, A; Oguri, H; Ohkoshi, K; Ikegami, K; Takagi, A; Asano, H; Naito, F

    2016-02-01

    A numerical model of plasma transport and electromagnetic field in the J-PARC (Japan Proton Accelerator Research Complex) radio frequency ion source has been developed to understand the relation between antenna coil heat loadings and plasma production/transport processes. From the calculation, the local plasma density increase is observed in the region close to the antenna coil. Electrons are magnetized by the magnetic field line with absolute magnetic flux density 30-120 Gauss which leads to high local ionization rate. The results suggest that modification of magnetic configuration can be made to reduce plasma heat flux onto the antenna. PMID:26932010

  1. Sources and contributions of wood smoke during winter in London: assessing local and regional influences

    NASA Astrophysics Data System (ADS)

    Crilley, L. R.; Bloss, W. J.; Yin, J.; Beddows, D. C. S.; Harrison, R. M.; Allan, J. D.; Young, D. E.; Flynn, M.; Williams, P.; Zotter, P.; Prevot, A. S. H.; Heal, M. R.; Barlow, J. F.; Halios, C. H.; Lee, J. D.; Szidat, S.; Mohr, C.

    2015-03-01

    Determining the contribution of wood smoke to air pollution in large cities such as London is becoming increasingly important due to the changing nature of domestic heating in urban areas. During winter, biomass burning emissions have been identified as a major cause of exceedances of European air quality limits. The aim of this work was to quantify the contribution of biomass burning in London to concentrations of PM2.5 and determine whether local emissions or regional contributions were the main source of biomass smoke. To achieve this, a number of biomass burning chemical tracers were analysed at a site within central London and two sites in surrounding rural areas. Concentrations of levoglucosan, elemental carbon (EC), organic carbon (OC) and K+ were generally well correlated across the three sites. At all the sites, biomass burning was found to be a source of OC and EC, with the largest contribution of EC from traffic emissions, while for OC the dominant fraction included contributions from secondary organic aerosols, primary biogenic and cooking sources. Source apportionment of the EC and OC was found to give reasonable estimation of the total carbon from non-fossil and fossil fuel sources based upon comparison with estimates derived from 14C analysis. Aethalometer-derived black carbon data were also apportioned into the contributions from biomass burning and traffic and showed trends similar to those observed for EC. Mean wood smoke mass at the sites was estimated to range from 0.78 to 1.0 μg m-3 during the campaign in January-February 2012. Measurements on a 160 m tower in London suggested a similar ratio of brown to black carbon (reflecting wood burning and traffic respectively) in regional and London air. Peaks in the levoglucosan and K+ concentrations were observed to coincide with low ambient temperature, consistent with domestic heating as a major contributing local source in London. Overall, the source of biomass smoke in London was concluded to be a

  2. Transition to chaos in a square enclosure containing internal heat sources

    SciTech Connect

    Baytas, A.C.

    1995-09-01

    A numerical investigation is performed to study the transition from steady to chaotic flow of a fluid confined in a two-dimensional square cavity. The cavity has rigid walls of constant temperature containing uniformly distributed internal heat source. Effects of the Rayleigh number of flow and heat transfer rates are studied. In addition to, same problem is solved for sinusoidally changing internal heat source to show its effect on the flow model and heat transfer of the enclosures. Details of oscillatory solutions and flow bifurcations are presented.

  3. Negative hydrogen ion beam extraction from an AC heated cathode driven Bernas-type ion source

    NASA Astrophysics Data System (ADS)

    Okano, Y.; Miyamoto, N.; Kasuya, T.; Wada, M.

    2015-04-01

    A plasma grid structure was installed to a Bernas-type ion source used for ion implantation equipment. A negative hydrogen (H-) ion beam was extracted by an AC driven ion source by adjusting the bias to the plasma grid. The extracted electron current was reduced by positively biasing the plasma grid, while an optimum plasma grid bias voltage for negative ion beam extraction was found to be positive 3 V with respect to the arc chamber. Source operations with AC cathode heating show extraction characteristics almost identical to that with DC cathode heating, except a minute increase in H- current at higher frequency of cathode heating current.

  4. General-Purpose Heat Source safety verification test series: SVT-1 through SVT-6

    NASA Astrophysics Data System (ADS)

    Pavone, D.; George, T. G.; Frantz, C. E.

    1985-06-01

    The General-Purpose Heat Source (GPHS) is a modular heat source that will supply energy for Radioisotope Thermoelectric Generators (RTGs) in space missions. The Safety Verification Tests (SVTs) are performed to assess the plutonium containment capability of heat source modules subjected to certain accident environments. This interim report described the GPHS module configuration, the test environment, and the response of the module components following simulated reentry and solid Earth impact. The specific test environment of these initial six tests results from failure of the booster rocket to place the spacecraft in a proper trajectory and subsequent reentry of the GPHS modules from Earth orbit.

  5. Federal Technology Alert: Ground-Source Heat Pumps Applied to Federal Facilities--Second Edition

    SciTech Connect

    Hadley, Donald L.

    2001-03-01

    This Federal Technology Alert, which was sponsored by the U.S. Department of Energy's Office of Federal Energy Management Programs, provides the detailed information and procedures that a Federal energy manager needs to evaluate most ground-source heat pump applications. This report updates an earlier report on ground-source heat pumps that was published in September 1995. In the current report, general benefits of this technology to the Federal sector are described, as are ground-source heat pump operation, system types, design variations, energy savings, and other benefits. In addition, information on current manufacturers, technology users, and references for further reading are provided.

  6. The dependence of F-region electron heating on HF radio pump power: Measurements at EISCAT Tromsø

    NASA Astrophysics Data System (ADS)

    Senior, A.; Rietveld, M. T.; Yeoman, T. K.; Kosch, M. J.

    2012-04-01

    Measurements of ionospheric electron temperature enhanced by the action of a powerful high-frequency radio wave on the F-region at the EISCAT facility near Tromsø, Norway are analyzed to obtain the electron heat source due to the radio wave as a function of transmitter power. The absorption of the wave in the D-region is accounted for and is found to have a significant influence on the F-region heating, especially due to variations in the D-region electron density during the experiment. It is found that the efficiency of F-region heating expressed in terms of the electron heating rate as a function of radio wave power flux is higher at higher transmitter powers. This behavior seems to be consistent with the development of geomagnetic field-aligned plasma density irregularities which are associated with the conversion of the radio wave to electrostatic upper-hybrid waves. At the highest power fluxes, the efficiency appears to be close to 100%.

  7. Evaluating the heat pump alternative for heating enclosed wastewater treatment facilities in cold regions

    NASA Astrophysics Data System (ADS)

    Martel, C. J.; Phetteplace, G. E.

    1982-05-01

    This report presents a five-step procedure for evaluating the technical and economic feasibility of using heat pumps to recover heat from treatment plant effluent. The procedure is meant to be used at the facility planning level by engineers who are unfamiliar with this technology. An example of the use of the procedure and general design information are provided. Also, the report reviews the operational experience with heat pumps at wastewater plants located in Fairbanks, Alaska, Madison, Wisconsin, and Wilton, Maine.

  8. The structural design of the experimental equipment for unconventional heating water using heat transfer surfaces located in the heat source

    NASA Astrophysics Data System (ADS)

    Kaduchová, K.; Lenhard, R.; Gavlas, S.; Jandačka, J.

    2013-04-01

    Flue gas temperature at throat of most industrially produced fireplaces is around 250 to 350 °C. It's quite interesting thermal potential, which can be even before sucking up the chimney back utilize. One of the potential uses of this device to heat the hot water. Article refers to the structural design of such a device, which works with the transfer of heat through a substance changes phase from liquid to steam in a sealed tube (heat pipe). Benefits of heat pipes is their light weight, the thermal effect of a rapid and low maintenance costs.

  9. Interplanetary magnetic field and solar cycle dependence of Northern Hemisphere F region joule heating

    NASA Astrophysics Data System (ADS)

    Bjoland, L. M.; Chen, X.; Jin, Y.; Reimer, A. S.; Skjæveland, Å.; Wessel, M. R.; Burchill, J. K.; Clausen, L. B. N.; Haaland, S. E.; McWilliams, K. A.

    2015-02-01

    Joule heating in the ionosphere takes place through collisions between ions and neutrals. Statistical maps of F region Joule heating in the Northern Hemisphere polar ionosphere are derived from satellite measurements of thermospheric wind and radar measurements of ionospheric ion convection. Persistent mesoscale heating is observed near postnoon and postmidnight magnetic local time and centered around 70° magnetic latitude in regions of strong relative ion and neutral drift. The magnitude of the Joule heating is found to be largest during solar maximum and for a southeast oriented interplanetary magnetic field. These conditions are consistent with stronger ion convection producing a larger relative flow between ions and neutrals. The global-scale Joule heating maps quantify persistent (in location) regions of heating that may be used to provide a broader context compared to small-scale studies of the coupling between the thermosphere and ionosphere.

  10. Alternate energy source usage for in situ heat treatment processes

    SciTech Connect

    Stone, Jr., Francis Marion; Goodwin, Charles R.; Richard, Jr., James

    2011-03-22

    Systems, methods, and heaters for treating a subsurface formation are described herein. At least one system for providing power to one or more subsurface heaters is described herein. The system may include an intermittent power source; a transformer coupled to the intermittent power source, and a tap controller coupled to the transformer. The transformer may be configured to transform power from the intermittent power source to power with appropriate operating parameters for the heaters. The tap controller may be configured to monitor and control the transformer so that a constant voltage is provided to the heaters from the transformer regardless of the load of the heaters and the power output provided by the intermittent power source.

  11. The source regions of the solar wind revealed by UV/EUV spectroscopic observations

    NASA Astrophysics Data System (ADS)

    Xia, L.

    2012-06-01

    The heating of the solar corona and the origin and acceleration of the solar wind are among the important unsolved problems of space plasma and solar physics. During the SOHO era, coronal holes as source regions of the fast solar wind have been investigated by using UV/EUV spectroscopic data observed with high-resolution spectrometers. At the base of the coronal hole, a detailed picture concerning the origin of the fast solar wind was first obtained by SUMER observations. For example, the Dopplergram deduced from the line profile of Ne VIII and other transition-region lines showed strong evidence that the wind originates in the chromospheric network and starts flowing out of the corona in magnetic funnels. Solar wind mass is suggested to be supplied through supergranule-scale magnetoconvection in the chromosphere and transition region. However, the spectral lines used in these studies are mainly obtained in the transition region and the behaviours of the nascent solar wind at higher temperatures have not yet been understood. Recent spectroscopic and imaging observations with instruments on Hinode and SDO provide further information about the coronal holes seen in EUV lines formed in the solar corona. Some interesting results, e.g., ubiquitous episodic outflow (jets) and enhanced emission in the blue wing of coronal line profiles, are found from the new observations. The purpose of this presentation is to review recent research progress on solar-wind source regions revealed by UV/EUV spectroscopic and imaging observations. Such observational studies and further interpretations of the data may provide crucial constraints and implications for future studies on both observations and theoretical models concerning coronal heating and acceleration of the nascent solar wind.

  12. Getting granite dikes out of the source region

    NASA Technical Reports Server (NTRS)

    Rubin, Allan M.

    1995-01-01

    Whether a dike can propagate far from a magma reservoir depends upon the competition between the rate at which propagation widens the dike and the rate at which freezing constricts the aperture available for magma flow. Various formulations are developed for a viscous fluid at temperature T(sub m) intruding a growing crack in an elastic solid. The initial solid temperature equals T(sub m) at the source and decreases linearly with distance from the source. If T(sub m) is the unique freezing temperature of the fluid, dike growth is initially self-similar and an essentially exact solution is obtained; if T(sub m) is above the solidus temperature, the solution is approximate but is designed to overestimate the distance the dike may propagate. The ability of a dike to survive thermally depends primarily upon a single parameter that is a measure of the ratio of the dike frozen margin thickness to elastic thickness. Perhaps more intuitively, one may define a minimum distance from the essentially solid reservoir wall to the point at which the host rock temperature drops below the solidus, necessary for dikes to propagate far into subsolidus rock. It is concluded that for reasonable material properties and source conditions, most basalt dikes will have little difficulty leaving the source region, but most rhyolite dikes will be halted by freezing soon after the magma encounters rock at temperatures below the magma solidus. While these results can explain why granitic dikes are common near granitic plutons but rare elsewhere, the potentially large variation in magmatic systems makes it premature to rule out the possibility that most granites are transported through the crust in dikes. Nonetheless, these results highlight difficulties with such proposals and suggest that it may also be premature to rule out the possibility that most granite plutons ascend as more equidimensional bodies.

  13. Heat transport by fluids during late Cretaceous regional metamorphism in the Big Maria Mountains, southeastern California.

    USGS Publications Warehouse

    Hoisch, T.D.

    1987-01-01

    The Big Maria Mountains of SE California preserve evidence of a large-scale fluid flux that accompanied regional metamorphism in late Cretaceous time. Neither magmatism nor radioactive heat sources are adequate to explain the T of metamorphism. Simultaneously crystallizing plutons at different levels within the crust could have contributed to the overall hot fluid flux. A fluid:rock ratio of 17:1 may be calculated given average conditions of 3 kbar, 500oC, an infiltrating fluid of composition XH2O = 1.0, an equilibrium fluid composition of XH2O = 0.97, and 90% wollastonite in the final rock form the reaction quartz + calcite = CO2 + wollastonite. The minimum quantity of fluid of 1.7 rock volume was estimated to pass through the area if the fluid was approximately at granite solidus T at the start. Deep penetrative structures within the crust may have served to channel fluids. -L.C.H.

  14. Characterization of the Inductively Heated Plasma Source IPG6-B

    NASA Astrophysics Data System (ADS)

    Dropmann, Michael; Laufer, Rene; Herdrich, Georg; Matthews, Lorin; Hyde, Truell

    2014-10-01

    In close collaboration between the Center for Astrophysics, Space Physics and Engineering Research (CASPER) at Baylor University, Texas, and the Institute of Space Systems (IRS) at the University of Stuttgart, Germany, two plasma facilities have been established using the Inductively heated Plasma Generator 6 (IPG6). The facility at Baylor University (IPG6-B) works at a frequency of 13.56 MHz and a maximum power of 15 kW. A vacuum pump of 160 m3/h in combination with a butterfly valve allows pressure control over a wide range. Intended fields of research include basic investigation into thermo-chemistry and plasma radiation, space plasma environments and high heat fluxes e.g. those found in fusion devices or during atmospheric re-entry of spacecraft. After moving the IPG6-B facility to the Baylor Research and Innovation Collaborative (BRIC) it was placed back into operation during the summer of 2014. Initial characterization in the new lab, using a heat flux probe, Pitot probe and cavity calorimeter, has been conducted for Air, Argon and Helium. The results of this characterization are presented.

  15. National Certification Standard for Ground Source Heat Pump Personnel

    SciTech Connect

    Kelly, John

    2013-07-31

    The National Certification Standard for the Geothermal Heat Pump Industry adds to the understanding of the barriers to rapid growth of the geothermal heat pump (GHP) industry by bringing together for the first time an analysis of the roles and responsibilities of each of the individual job tasks involved in the design and installation of GHP systems. The standard addresses applicable qualifications for all primary personnel involved in the design, installation, commissioning, operation and maintenance of GHP systems, including their knowledge, skills and abilities. The resulting standard serves as a foundation for subsequent development of curriculum, training and certification programs, which are not included in the scope of this project, but are briefly addressed in the standard to describe ways in which the standard developed in this project may form a foundation to support further progress in accomplishing those other efforts. Follow-on efforts may use the standard developed in this project to improve the technical effectiveness and economic feasibility of curriculum development and training programs for GHP industry personnel, by providing a more complete and objective assessment of the individual job tasks necessary for successful implementation of GHP systems. When incorporated into future certification programs for GHP personnel, the standard will facilitate increased consumer confidence in GHP technology, reduce the potential for improperly installed GHP systems, and assure GHP system quality and performance, all of which benefit the public through improved energy efficiency and mitigated environmental impacts of the heating and cooling of homes and businesses.

  16. The numerical simulation of heat transfer during a hybrid laser-MIG welding using equivalent heat source approach

    NASA Astrophysics Data System (ADS)

    Bendaoud, Issam; Matteï, Simone; Cicala, Eugen; Tomashchuk, Iryna; Andrzejewski, Henri; Sallamand, Pierre; Mathieu, Alexandre; Bouchaud, Fréderic

    2014-03-01

    The present study is dedicated to the numerical simulation of an industrial case of hybrid laser-MIG welding of high thickness duplex steel UR2507Cu with Y-shaped chamfer geometry. It consists in simulation of heat transfer phenomena using heat equivalent source approach and implementing in finite element software COMSOL Multiphysics. A numerical exploratory designs method is used to identify the heat sources parameters in order to obtain a minimal required difference between the numerical results and the experiment which are the shape of the welded zone and the temperature evolution in different locations. The obtained results were found in good correspondence with experiment, both for melted zone shape and thermal history.

  17. Optimum bleeding rate of open loop ground source heat pump systems determined by hydrogeological modeling in Korea

    NASA Astrophysics Data System (ADS)

    Jeon, W. H.; Kim, N.; Lee, J. Y.

    2014-12-01

    This study aims to evaluate the influence of open loop ground source heat pump systems operation on hydrological conditions of aquifer. Test bed is located in Chuncheon, Korea. The step drawdown test was conducted in five stages for 300 minutes. The variation of groundwater levels by open loop ground source heat pump systems operation was estimated using Visual MODFLOW. Transmissivity ranged from 2.02×10-4 to 9.36×10-4, and storage coefficient ranged from 0.00067 to 0.021. The amount of optimum bleeding was calculated to be 240 m3/day. When bleeding will be 50, 90, 240 and 450 m3/day for 5 years, groundwater levels may decrease 1.84, 3.31, 8.89 and 17.0 m, respectively. If the amount of bleeding is 50 m3/day, the influence of bleeding will not reach the boundary regions of the Soyang River after 5 years. Regarding the open loop ground source heat pump system installed at the test bed, the amount of optimum bleeding in accordance with the stand are proposed by the government is 90 m3/day, which is 20% of the 450 m3/day circulation quantity of the system. However, if continuous bleeding of more than 90 m3/day occurs, then the radius of influence is expected to reach the boundary regions of the Soyang River after 5 years. These results indicate that amount of optimum bleeding differ in each open loop ground soured heat pump system. Therefore, the debate for the amount of optimum bleeding in open loop ground source heat pump systems is demanded. This work is supported by the Energy Efficiency and Resources of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Knowledge Economy (No.20123040110010).

  18. Fuel cell power source for a cold region

    NASA Astrophysics Data System (ADS)

    Datta, B. K.; Velayutham, G.; Goud, A. Prasad

    operation. Based on the results of these experiments, the design of the fuel cell power source for cold region application has been finalised. The paper deals with the design criteria and design factors to be considered for the fuel cell power source for cold region application and details of tests and test results that led to the final design concept for such an application. The paper also deals with a proposed hybrid power plant taking into account the exploitation of wind energy with a fuel cell and generation of hydrogen by an electrolyser and provision of hydrogen storage.

  19. An amplitude and phase control system for the TFTR rf heating sources

    SciTech Connect

    Cutsogeorge, G.

    1989-04-01

    Feedback loops that control the amplitude and phase of the rf heating sources on TFTR are described. The method for providing arc protection is also discussed. Block diagrams and Bode plots are included. 6 figs.

  20. Prospects for using high power x-rays as a volumetric heat source

    SciTech Connect

    Rosenberg, R.A.; Farrell, W.; Ma, Q.

    1997-09-01

    Third-generation, high-intensity, x-ray synchrotron radiation sources are capable of producing high heat-flux x-ray beams. In many applications finding ways to handle these powers is viewed as a burden. However, there are some technological applications where the deep penetration length of the x-rays may find beneficial uses as a volumetric heat source. In this paper the authors discuss the prospects for using high power x-rays for volumetric heating and report some recent experimental results. The particular applications they focus on are welding and surface heat treatment. The radiation source is an undulator at the Advanced Photon Source (APS). Results of preliminary tests on aluminum, aluminum metal matrix composites, and steel will be presented.

  1. Welding Isotopic Heat Sources for the Cassini Mission to Saturn (U)

    SciTech Connect

    Franco-Ferreira, E.A.; George, T.G.

    1995-02-28

    In 1997 NASA will launch the Cassini scientific probe to the planet Saturn. Electric power for this probe will be provided by Radioisotope Thermoelectric Generators thermally driven by General Purpose Heat Source modules.

  2. Impact of various operating modes on performance and emission parameters of small heat source

    NASA Astrophysics Data System (ADS)

    Vician, Peter; Holubčík, Michal; Palacka, Matej; Jandačka, Jozef

    2016-06-01

    Thesis deals with the measurement of performance and emission parameters of small heat source for combustion of biomass in each of its operating modes. As the heat source was used pellet boiler with an output of 18 kW. The work includes design of experimental device for measuring the impact of changes in air supply and method for controlling the power and emission parameters of heat sources for combustion of woody biomass. The work describes the main factors that affect the combustion process and analyze the measurements of emissions at the heat source. The results of experiment demonstrate the values of performance and emissions parameters for the different operating modes of the boiler, which serve as a decisive factor in choosing the appropriate mode.

  3. GEO3D - Three-Dimensional Computer Model of a Ground Source Heat Pump System

    SciTech Connect

    James Menart

    2013-06-07

    This file is the setup file for the computer program GEO3D. GEO3D is a computer program written by Jim Menart to simulate vertical wells in conjunction with a heat pump for ground source heat pump (GSHP) systems. This is a very detailed three-dimensional computer model. This program produces detailed heat transfer and temperature field information for a vertical GSHP system.

  4. Energy recovery during expansion of compressed gas using power plant low-quality heat sources

    DOEpatents

    Ochs, Thomas L.; O'Connor, William K.

    2006-03-07

    A method of recovering energy from a cool compressed gas, compressed liquid, vapor, or supercritical fluid is disclosed which includes incrementally expanding the compressed gas, compressed liquid, vapor, or supercritical fluid through a plurality of expansion engines and heating the gas, vapor, compressed liquid, or supercritical fluid entering at least one of the expansion engines with a low quality heat source. Expansion engines such as turbines and multiple expansions with heating are disclosed.

  5. Integration and Optimization of Alternative Sources of Energy in a Remote Region

    NASA Astrophysics Data System (ADS)

    Berberi, Pellumb; Inodnorjani, Spiro; Aleti, Riza

    2010-01-01

    In a remote coastal region supply of energy from national grid is insufficient for a sustainable development. Integration and optimization of local alternative renewable energy sources is an optional solution of the problem. In this paper we have studied the energetic potential of local sources of renewable energy (water, solar, wind and biomass). A bottom-up energy system optimization model is proposed in order to support planning policies for promoting the use of renewable energy sources. A software, based on multiple factors and constrains analysis for optimization energy flow is proposed, which provides detailed information for exploitation each source of energy, power and heat generation, GHG emissions and end-use sectors. Economical analysis shows that with existing technologies both stand alone and regional facilities may be feasible. Improving specific legislation will foster investments from Central or Local Governments and also from individuals, private companies or small families. The study is carried on the frame work of a FP6 project "Integrated Renewable Energy System."

  6. Interactions of /sup 238/PuO/sub 2/ heat sources with terrestrial and aquatic environments. Interim summary

    SciTech Connect

    Patterson, J.H.; Steinkruger, F.J.; Matlack, G.M.

    1980-09-01

    Observations and some conclusions made of the interactions of /sup 238/PuO/sub 2/ heat sources with terrestrial and aquatic environments may be used in predicting heat source behavior in the event of contact of these heat sources with land or ocean and in assessing the risk to the environment. These studies indicate that plutonium transport from the heat sources is mostly a physical process involving the movement of extremely fine particles rather than the chemical migration of plutonium ions.

  7. Numerical analysis of the heat source characteristics of a two-electrode TIG arc

    NASA Astrophysics Data System (ADS)

    Ogino, Y.; Hirata, Y.; Nomura, K.

    2011-06-01

    Various kinds of multi-electrode welding processes are used to ensure high productivity in industrial fields such as shipbuilding, automotive manufacturing and pipe fabrication. However, it is difficult to obtain the optimum welding conditions for a specific product, because there are many operating parameters, and because welding phenomena are very complicated. In the present research, the heat source characteristics of a two-electrode TIG arc were numerically investigated using a 3D arc plasma model with a focus on the distance between the two electrodes. The arc plasma shape changed significantly, depending on the electrode spacing. The heat source characteristics, such as the heat input density and the arc pressure distribution, changed significantly when the electrode separation was varied. The maximum arc pressure of the two-electrode TIG arc was much lower than that of a single-electrode TIG. However, the total heat input of the two-electrode TIG arc was nearly constant and was independent of the electrode spacing. These heat source characteristics of the two-electrode TIG arc are useful for controlling the heat input distribution at a low arc pressure. Therefore, these results indicate the possibility of a heat source based on a two-electrode TIG arc that is capable of high heat input at low pressures.

  8. Technology Solutions Case Study: Ground Source Heat Pump Research, TaC Studios Residence, Atlanta, Georigia

    SciTech Connect

    2014-09-01

    This case study describes the construction of a new test home that demonstrates current best practices for the mixed-humid climate, including a high performance ground source heat pump for heating and cooling, a building envelope featuring advanced air sealing details and low-density spray foam insulation, and glazing that exceeds ENERGY STAR requirements.

  9. Foundation heat exchangers for residential ground source heat pump systems Numerical modeling and experimental validation

    SciTech Connect

    Xing, Lu; Cullin, James; Spitler, Jeffery; Im, Piljae; Fisher, Daniel

    2011-01-01

    A new type of ground heat exchanger that utilizes the excavation often made for basements or foundations has been proposed as an alternative to conventional ground heat exchangers. This article describes a numerical model that can be used to size these foundation heat exchanger (FHX) systems. The numerical model is a two-dimensional finite-volume model that considers a wide variety of factors, such as soil freezing and evapotranspiration. The FHX numerical model is validated with one year of experimental data collected at an experimental house located near Oak Ridge, Tennessee. The model shows good agreement with the experimental data-heat pump entering fluid temperatures typically within 1 C (1.8 F) - with minor discrepancies due to approximations, such as constant moisture content throughout the year, uniform evapotranspiration over the seasons, and lack of ground shading in the model.

  10. Multiscale modeling of electron beam and substrate interaction: a new heat source model

    NASA Astrophysics Data System (ADS)

    Yan, Wentao; Smith, Jacob; Ge, Wenjun; Lin, Feng; Liu, Wing Kam

    2015-08-01

    An electron beam is a widely applied processing tool in welding and additive manufacturing applications. The heat source model of the electron beam acts as the basis of thermal simulations and predictions of the micro-structures and mechanical properties of the final products. While traditional volumetric and surface heat flux models were developed previously based on the observed shape of the molten pool produced by the beam, a new heat source model with a physically informed foundation has been established in this work. The new model was developed based on Monte Carlo simulations performed to obtain the distribution of absorbed energy through electron-atom collisions for an electron beam with a kinetic energy of 60 keV hitting a Ti-6Al-4V substrate. Thermal simulations of a moving electron beam heating a solid baseboard were conducted to compare the differences between the new heat source model, the traditional surface flux model and the volumetric flux model. Although the molten pool shapes with the three selected models were found to be similar, the predicted peak temperatures were noticeably different, which will influence the evaporation, recoil pressure and molten pool dynamics. The new heat source model was also used to investigate the influence of a static electron beam on a substrate. This investigation indicated that the new heat source model could scientifically explain phenomena that the surface and volumetric models cannot, such as eruption and explosion during electron beam processing.

  11. Numerical Prediction of Performance of Water Type Stirling Engine Considering Heat Exchange with Heat Sources

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Yoshiyuki; Higuchi, Tetsuya

    Two different analytical models were developed on water type Stirling engine. One is the resonance model which qualitatively clarifies the relationship between performance and resonance tube length, and the other is the heat transfer model considering heat transfer between working gas and the tube walls of heating and cooling units. These analyses and experiments were carried out changing the resonance tube length variously, then it was confirmed that the resonance tube length which maximizes the water column amplitude of the power piston agrees well and the oscillations of water columns at that resonance tube length also agrees. In addition, a series of analysis using the heat transfer model was carried out with changing cross sectional area of the resonance tube, loss factors of the elbows, heat transfer area of heating and cooling unit, and pressure of working gas. By this numerical investigation, the effect on the resonance tube length and the work at the length in which these parameters maximize the amplitude of power piston water column was clarified.

  12. Optimal Operation System of the Integrated District Heating System with Multiple Regional Branches

    NASA Astrophysics Data System (ADS)

    Kim, Ui Sik; Park, Tae Chang; Kim, Lae-Hyun; Yeo, Yeong Koo

    This paper presents an optimal production and distribution management for structural and operational optimization of the integrated district heating system (DHS) with multiple regional branches. A DHS consists of energy suppliers and consumers, district heating pipelines network and heat storage facilities in the covered region. In the optimal management system, production of heat and electric power, regional heat demand, electric power bidding and sales, transport and storage of heat at each regional DHS are taken into account. The optimal management system is formulated as a mixed integer linear programming (MILP) where the objectives is to minimize the overall cost of the integrated DHS while satisfying the operation constraints of heat units and networks as well as fulfilling heating demands from consumers. Piecewise linear formulation of the production cost function and stairwise formulation of the start-up cost function are used to compute nonlinear cost function approximately. Evaluation of the total overall cost is based on weekly operations at each district heat branches. Numerical simulations show the increase of energy efficiency due to the introduction of the present optimal management system.

  13. Puna: a source region for the Pampean loess

    SciTech Connect

    Bloom, A.L.; Strecker, M.R.; Scoppa, C.

    1985-01-01

    The Quaternary Pampean loess of NE Argentina has the same texture and grain-size distribution as northern hemisphere loess, but a very different mineral composition. Unweathered calcic and intermediate plagioclase is the most abundant mineral in the sand fraction followed by quartz, orthoclase, volcanic glass, and fragments of volcanic rock. Glass shards make up more than one-half of the silt fraction in most samples, but their abundance is highly variable. Grain size increases toward the west and southwest, primarily by an increase in the proportion of sand. Most authorities infer a polygenetic source for the Pampean loess. Andean volcanoes and the Patagonian plains to the west and southwest are commonly mentioned, but there are almost no Quaternary volcanoes in the Andes between 28/sup 0/ and 34/sup 0/ S latitude, directly west of the main Pampean loess region. A previously unconsidered, mineralogically appropriate, and currently active source for the silt fraction of the Pampean loess is the Puna, the high plateau in NW Argentina where volcanism has been active throughout the late Cenozoic Era. Shuttle astronauts in September 1983 photographed streamers of dust blowing SE out of desert basins in the Puna, originating more than 3700 m above sea level. The dust was clearly visible above low clouds that covered the Pampas at the time, where surface winds were light and variable. Wind streaks and yardangs prove that eolian erosion is active in the Puna.

  14. Unveiling the sources of disk heating in spiral galaxies with the CALIFA survey

    NASA Astrophysics Data System (ADS)

    Pinna, F.; Falcón-Barroso, J.; Martig, M.; van de Ven, G.; Lyubenova, M.; Leaman, R.

    2016-06-01

    The stellar velocity ellipsoid (SVE) quantifies the amount of velocity dispersion in the vertical, radial and azimuthal directions. Since different disk heating mechanisms (e.g. spiral arms, giant molecular clouds, mergers, etc) affect these components differently, the SVE can constrain the sources of heating in disk galaxies. At present the 3D nature of the SVE can only be directly measured in the Milky Way but, thanks to integral-field surveys like CALIFA, we are now in position to carry out the same kind of analysis in external galaxies. For this purpose, we have gathered a sample of ~30 intermediate inclined spiral galaxies along the Hubble sequence (S0 to Scd types) with high quality stellar kinematic maps. This allows us to probe the SVE for each galaxy from different line-of-sights in different regions, and thus provide strong constraints on its shape. In this presentation we relate our preliminary findings to realistic numerical simulations of disks with different formation histories (quiescent vs mergers), and to results of previous works.

  15. High current multicharged metal ion source using high power gyrotron heating of vacuum arc plasma.

    PubMed

    Vodopyanov, A V; Golubev, S V; Khizhnyak, V I; Mansfeld, D A; Nikolaev, A G; Oks, E M; Savkin, K P; Vizir, A V; Yushkov, G Yu

    2008-02-01

    A high current, multi charged, metal ion source using electron heating of vacuum arc plasma by high power gyrotron radiation has been developed. The plasma is confined in a simple mirror trap with peak magnetic field in the plug up to 2.5 T, mirror ratio of 3-5, and length variable from 15 to 20 cm. Plasma formed by a cathodic vacuum arc is injected into the trap either (i) axially using a compact vacuum arc plasma gun located on axis outside the mirror trap region or (ii) radially using four plasma guns surrounding the trap at midplane. Microwave heating of the mirror-confined, vacuum arc plasma is accomplished by gyrotron microwave radiation of frequency 75 GHz, power up to 200 kW, and pulse duration up to 150 micros, leading to additional stripping of metal ions by electron impact. Pulsed beams of platinum ions with charge state up to 10+, a mean charge state over 6+, and total (all charge states) beam current of a few hundred milliamperes have been formed. PMID:18315170

  16. High current multicharged metal ion source using high power gyrotron heating of vacuum arc plasma

    SciTech Connect

    Vodopyanov, A. V.; Golubev, S. V.; Khizhnyak, V. I.; Mansfeld, D. A.; Nikolaev, A. G.; Oks, E. M.; Savkin, K. P.; Vizir, A. V.; Yushkov, G. Yu.

    2008-02-15

    A high current, multi charged, metal ion source using electron heating of vacuum arc plasma by high power gyrotron radiation has been developed. The plasma is confined in a simple mirror trap with peak magnetic field in the plug up to 2.5 T, mirror ratio of 3-5, and length variable from 15 to 20 cm. Plasma formed by a cathodic vacuum arc is injected into the trap either (i) axially using a compact vacuum arc plasma gun located on axis outside the mirror trap region or (ii) radially using four plasma guns surrounding the trap at midplane. Microwave heating of the mirror-confined, vacuum arc plasma is accomplished by gyrotron microwave radiation of frequency 75 GHz, power up to 200 kW, and pulse duration up to 150 {mu}s, leading to additional stripping of metal ions by electron impact. Pulsed beams of platinum ions with charge state up to 10+, a mean charge state over 6+, and total (all charge states) beam current of a few hundred milliamperes have been formed.

  17. Solar source regions of 3HE-rich particle events

    NASA Technical Reports Server (NTRS)

    Reames, D. V.; Stone, R. G.; Kahler, S. W.; Lin, R. P.; Liggett, M.

    1985-01-01

    Hydrogen alpha X-ray, and metric and kilometric radio data to examine the solar sources of energetic 3He-rich particle events observed near earth in association with impulsive 2 to 100 keV electron events were applied. Each 3He/electron event is associated with a kilometric type 3 burst belonging to a family of such bursts characterized by similar interplanetary propagation paths from the same solar active region. The 3He/electron events correlate very well with the interplanetary low frequency radio brightnesses of these events, but progressively worse with signatures from regions closer to the Sun. When H alpha brightnings can be associated with 3He/electron events, they have onsets coinciding to within 1 min of that of the associated metric type 3 burst but are often too small to be reported. The data are consistent with the earlier idea that many type 3 bursts, the 3He/electron events, are due to particle acceleration in the corona, well above the associated H alpha and X-ray flares.

  18. Nuclear heat load calculations for the NBSR cold neutron source using MCNP

    SciTech Connect

    Blau, M. ); Rowe, J.M.; Williams, R.E. )

    1993-01-01

    A liquid-hydrogen (LH2) cold neutron source is being designed for installation in the 20-MW National Bureau of Standards reactor (NBSR) at National Institute of Standards and Technology to replace the D[sub 2]O-ice cold source currently in use. An accurate estimate of the heat deposited in the cold source is needed to ensure that it can be adequately cooled for successful operation. The heat load is caused by the interaction of neutrons and gamma rays with the cold moderator and the walls of the moderator chamber. The Monte Carlo code, MCNP (Version 4.2), was used to model the entire NBSR core and both the existing and the proposed cold sources. The model was used to calculate not only the heat load but also the reactivity and neutron gain of each source.

  19. Comparison of energy efficiency between variable refrigerant flow systems and ground source heat pump systems

    SciTech Connect

    Hong, Tainzhen; Liu, Xaiobing

    2009-11-01

    With the current movement toward net zero energy buildings, many technologies are promoted with emphasis on their superior energy efficiency. The variable refrigerant flow (VRF) and ground source heat pump (GSHP) systems are probably the most competitive technologies among these. However, there are few studies reporting the energy efficiency of VRF systems compared with GSHP systems. In this article, a preliminary comparison of energy efficiency between the air-source VRF and GSHP systems is presented. The computer simulation results show that GSHP system is more energy efficient than the air-source VRF system for conditioning a small office building in two selected US climates. In general, GSHP system is more energy efficient than the air-source VRV system, especially when the building has significant heating loads. For buildings with less heating loads, the GSHP system could still perform better than the air-source VRF system in terms of energy efficiency, but the resulting energy savings may be marginal.

  20. Impact of the High Flux Isotope Reactor HEU to LEU Fuel Conversion on Cold Source Nuclear Heat Generation Rates

    SciTech Connect

    Chandler, David

    2014-03-01

    Under the sponsorship of the US Department of Energy National Nuclear Security Administration, staff members at the Oak Ridge National Laboratory have been conducting studies to determine whether the High Flux Isotope Reactor (HFIR) can be converted from high enriched uranium (HEU) fuel to low enriched uranium (LEU) fuel. As part of these ongoing studies, an assessment of the impact that the HEU to LEU fuel conversion has on the nuclear heat generation rates in regions of the HFIR cold source system and its moderator vessel was performed and is documented in this report. Silicon production rates in the cold source aluminum regions and few-group neutron fluxes in the cold source moderator were also estimated. Neutronics calculations were performed with the Monte Carlo N-Particle code to determine the nuclear heat generation rates in regions of the HFIR cold source and its vessel for the HEU core operating at a full reactor power (FP) of 85 MW(t) and the reference LEU core operating at an FP of 100 MW(t). Calculations were performed with beginning-of-cycle (BOC) and end-of-cycle (EOC) conditions to bound typical irradiation conditions. Average specific BOC heat generation rates of 12.76 and 12.92 W/g, respectively, were calculated for the hemispherical region of the cold source liquid hydrogen (LH2) for the HEU and LEU cores, and EOC heat generation rates of 13.25 and 12.86 W/g, respectively, were calculated for the HEU and LEU cores. Thus, the greatest heat generation rates were calculated for the EOC HEU core, and it is concluded that the conversion from HEU to LEU fuel and the resulting increase of FP from 85 MW to 100 MW will not impact the ability of the heat removal equipment to remove the heat deposited in the cold source system. Silicon production rates in the cold source aluminum regions are estimated to be about 12.0% greater at BOC and 2.7% greater at EOC for the LEU core in comparison to the HEU core. Silicon is aluminum s major transmutation product and

  1. Nanofluid flow and forced convection heat transfer over a stretching surface considering heat source

    NASA Astrophysics Data System (ADS)

    Mohammadpour, M.; Valipour, P.; Shambooli, M.; Ayani, M.; Mirparizi, M.

    2015-07-01

    In this paper, magnetic field effects on the forced convection flow of a nanofluid over a stretching surface in the presence of heat generation/absorption are studied. The equations of continuity, momentum and energy are transformed into ordinary differential equations and solved numerically using the fourth-order Runge-Kutta integration scheme featuring the shooting technique. Different types of nanoparticles as copper (Cu), silver (Ag), alumina (Al2O3) and titania (TiO2) with water as their base fluid has been considered. The influence of significant parameters, such as magnetic parameter, volume fraction of the nanoparticles, heat generation/absorption parameter, velocity ratio parameter and temperature index parameter on the flow and heat transfer characteristics are discussed. The results show that the values of temperature profiles increase with increasing heat generation/absorption and volume fraction of the nanoparticles but they decrease with increasing velocity ratio parameter and temperature index parameter. Also, it can be found that selecting silver as nanoparticle leads to the highest heat transfer enhancement.

  2. Identification of potential sources and source regions of fine ambient particles measured at Gosan background site in Korea using advanced hybrid receptor model combined with positive matrix factorization

    NASA Astrophysics Data System (ADS)

    Han, J. S.; Moon, K. J.; Kim, Y. J.

    2006-11-01

    The size- and time-resolved measurement of particulate trace elements was made using an eight-stage Davis Rotating Unit for Monitoring sampler and synchrotron X-ray fluorescence system from 29 March to 29 May in 2002 at Gosan, Korea, which is one of the representative background sites in east Asia. As a result, continuous 3-hour average concentrations were obtained for 19 elements including S, Si, Al, Fe, Ca, Cl, Cu, Zn, Ti, K, Mn, Pb, Ni, V, Se, As, Rb, Cr, and Br. Positive matrix factorization (PMF) method was applied to the size-resolved aerosol data sets in order to identify the possible sources and to estimate their contribution to particulate matter mass in each size range. Twelve sources were then resolved in the fine size range (0.07 ˜ 1.15 μm), including continental aerosol, biomass burning, coal combustion, oil heating furnace, residual oil fired boiler, municipal incineration, nonferrous metal source, ferrous metal source, gasoline vehicle, diesel vehicle, copper smelter, and volcanic emission. A newly developed hybrid receptor model, concentration, retention time, and source emission weighted trajectory (CRSWT), was then applied to the source intensities derived from the PMF analysis by incorporating meteorological and source inventory information of the study region in order to suggest the regional information of long-range transported fine aerosol sources. The CRSWT model was able to resolve highly potential source areas and pathways for the fine ambient aerosol at the Gosan background site.

  3. Wake-induced unsteady stagnation-region heat-transfer measurements

    NASA Technical Reports Server (NTRS)

    Magari, P. J.; Lagraff, L. E.

    1992-01-01

    Results of an experimental investigation of wake-induced unsteady heat transfer in the stagnation region of a cylinder are presented. A quasi-steady representation of the stator/rotor interaction in a gas turbine using two stationary cylinders in crossflow is created. Time-averaged and time-resolved heat-transfer results are obtained over a wide range of Reynolds numbers at two Mach numbers: one incompressible and one transonic. The augmentation of the heat transfer in the stagnation region due to wake unsteadiness is documented by comparison with isolated cylinder tests. The time-averaged heat-transfer rate at the stagnation line, expressed in terms of the Frossling number, is found to reach a maximum independent of the Reynolds number. The power spectra and cross correlation of the heat-transfer signals in the stagnation region reveal the importance of large vortical structures shed from the upstream wake generator.

  4. Wake-induced unsteady stagnation-region heat-transfer measurements

    SciTech Connect

    Magari, P.J.; Lagraff, L.E. )

    1992-01-01

    Results of an experimental investigation of wake-induced unsteady heat transfer in the stagnation region of a cylinder are presented. A quasi-steady representation of the stator/rotor interaction in a gas turbine using two stationary cylinders in crossflow is created. Time-averaged and time-resolved heat-transfer results are obtained over a wide range of Reynolds numbers at two Mach numbers: one incompressible and one transonic. The augmentation of the heat transfer in the stagnation region due to wake unsteadiness is documented by comparison with isolated cylinder tests. The time-averaged heat-transfer rate at the stagnation line, expressed in terms of the Frossling number, is found to reach a maximum independent of the Reynolds number. The power spectra and cross correlation of the heat-transfer signals in the stagnation region reveal the importance of large vortical structures shed from the upstream wake generator. 30 refs.

  5. Safe radioisotope thermoelectric generators and heat sources for space applications

    NASA Astrophysics Data System (ADS)

    O'Brien, R. C.; Ambrosi, R. M.; Bannister, N. P.; Howe, S. D.; Atkinson, H. V.

    2008-07-01

    Several isotopes are examined as alternatives to 238Pu that is traditionally used in radioisotope thermoelectric generators (RTGs) and heating units (RHUs). The radioisotopes discussed include 241Am, 208Po, 210Po, and 90Sr. The aim of this study is to facilitate the design of an RTG with a minimal radiation dose rate and mass including any required shielding. Applications of interest are primarily space and planetary exploration. In order to evaluate the properties of the alternative radioisotopes a Monte Carlo model was developed to examine the radiation protection aspect of the study. The thermodynamics of the power generation process is examined and possible materials for the housing and encapsulation of the radioisotopes are proposed. In this study we also present a historical review of radioisotope thermoelectric generators (RTGs) and the thermoelectric conversion mechanism in order to provide a direct comparison with the performance of our proposed alternative isotope systems.

  6. Regional heat loss in resting man during immersion in 25.2 degrees C water.

    PubMed

    Wade, C E; Dacanay, S; Smith, R M

    1979-06-01

    Five male subjects having a wide range of relative body fat, 9.2-20.2%, were studied during total body immersion in water at 25.2 degrees C. The regional surface area of each subject was calculated from anthropometric data utilizing a segmental geometric model. Skin temperatures (Tsk) and regional skin heat loss were measured prior to and during 30 min immersion at 13 sites. During immersion, mean Tsk was 25.9 degrees C and remained significantly higher than the water temperature. A measurable temperature gradient for heat flow was observed from all body segments. Segimental temperature in water ranged from 26.7-25.4 degrees C, being warmest at the neck and coolest at the foot. Heat the flow per regional area was highest in the neck, 187 W/m2, and least at the foot, 12 W/m2. Heat flow from each body region was dependent on regional Tsk. Skinfold thickness was a minor factor in altering regional heat flow in the foot, hand, lower arm, upper arm, thigh, and calf; in the torso, neck, and head regions it was of major importance in detering heat loss. PMID:475707

  7. Regional lightning NOx sources during the TROCCINOX experiment

    NASA Astrophysics Data System (ADS)

    Mari, C.; Chaboureau, J. P.; Pinty, J. P.; Duron, J.; Mascart, P.; Cammas, J. P.; Gheusi, F.; Fehr, T.; Schlager, H.; Roiger, A.; Lichtenstein, M.; Stock, P.

    2006-12-01

    times of maximun convective activity. Extrapolation of the regional LiNOx source would yield a global LiNOx production around 5.7 Tg(N)/year which is within the current estimates but should not hide the overestimation of the number of flash rates by the model.

  8. Impact factors on the long-term sustainability of Borehole Heat Exchanger coupled Ground Source Heat Pump System

    NASA Astrophysics Data System (ADS)

    Shao, Haibing; Hein, Philipp; Görke, Uwe-Jens; Bucher, Anke; Kolditz, Olaf

    2016-04-01

    In recent years, Ground Source Heat Pump System (GSHPS) has been recognized as an efficient technology to utilize shallow geothermal energy. Along with its wide application, some GSHPS are experiencing a gradual decrease in Borehole Heat Exchanger (BHE) outflow temperatures and thus have to be turned off after couple of years' operation. A comprehensive numerical investigation was then performed to model the flow and heat transport processes in and around the BHE, together with the dynamic change of heat pump efficiency. The model parameters were based on the soil temperature and surface weather condition in the Leipzig area. Different scenarios were modelled for a service life of 30 years, to reveal the evolution of BHE outflow and surrounding soil temperatures. It is found that lateral groundwater flow and using BHE for cooling will be beneficial to the energy recovery, along with the efficiency improvement of the heat pump. In comparison to other factors, the soil heat capacity and thermal conductivity are considered to have minor impact on the long-term sustainability of the system. Furthermore, the application of thermally enhanced grout material will improve the sustainability and efficiency. In contrast, it is very likely that undersized systems and improper grouting are the causes of strong system degradation.

  9. The Power Source(s) of Nearby Low-Ionization Nuclear Emission Regions

    NASA Astrophysics Data System (ADS)

    Molina, Mallory; Eracleous, Michael; Maoz, Dan; Barth, Aaron J.; Walsh, Jonelle; Ho, Luis C.; Shields, Joseph C.

    2015-01-01

    The majority of low-ionization nuclear emission regions (LINERs) harbor supermassive black holes (SMBHs) with very low accretion rates. Since SMBHs spend most of their lifetimes in these low-accretion rate states, understanding LINERs is important for understanding active galactic nuclei (AGN) in the context of galaxy evolution. On scales of ~100 pc, the energy budget of LINERs appears to be deficient when the only source of power considered is the AGN. Thus, other energy sources are likely to contribute to the excitation of the emission-line gas. To probe these sources, we observed three nearby, bright LINERs, NGC 1052, NGC 4278 and NGC 4579, with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope (HST). We specifically looked at the 0.1-1 arcsecond (corresponding to 5-50 pc) scale to find what and how far from the nucleus these other energy sources are. After subtracting both the unresolved nuclear light and the spatially-extended starlight, we measured a number of diagnostic emission line ratios. We find that line ratios, such as [O III]/[O II] and [O III]/H-beta change as a function of distance from the nucleus. Within 5 pc, the line ratios suggest AGN photoionization. At larger distances the line ratios seem to be inconsistent with AGN photoionization, but they appear to be consistent with excitation by hot stars or shocks.

  10. Behavioral observations and operant procedures using microwaves as a heat source for young chicks

    SciTech Connect

    Morrison, W.D.; McMillan, I.; Bate, L.A.; Otten, L.; Pei, D.C.

    1986-08-01

    Four trials, using operant conditioning procedures, were conducted to study the response of chicks, housed at 16 C, to microwave or infrared heat. Microwave power density was 26 mW/cm2 in Trial 1, 13 mW/cm2 in Trial 2, and 10 mW/cm2 in Trials 3 and 4. Chicks voluntarily demanded between 28 and 63% as much heat (min heat/hr) from microwave source as from infrared source at all power densities. There was no correlation, however, between the ratio of heat demanded and the power density used. There were no significant differences in growth between infrared- or microwave-heated chicks. It is evident from these studies that 8-day-old broiler chicks are capable of associating the performance of a task with a thermal reward provided by the microwaves. They are also able to utilize these microwaves through operant conditioning without any visible detrimental effect to their health or behavior.

  11. Synergistic effect of solar radiation and solar heating to disinfect drinking water sources.

    PubMed

    Rijal, G K; Fujioka, R S

    2001-01-01

    Waterborne diseases are still common in developing countries as drinking water sources are contaminated and feasible means to reliably treat and disinfect these waters are not available. Many of these developing countries are in the tropical regions of the world where sunlight is plentiful. The objective of this study was to evaluate the effectiveness of combining solar radiation and solar heating to disinfect contaminated water using a modified Family Sol*Saver System (FSP). The non-UV transmittable cover sheet of the former FSP system was replaced with an UV transmittable plastic cover sheet to enable more wavelengths of sunlight to treat the water. Disinfection efficiency of both systems was evaluated based on reduction of the natural populations of faecal coliform, E. coli, enterococci, C. perfringens, total heterotrophic bacteria, hydrogen sulphide producing bacteria and FRNA virus. The results showed that under sunny and partly sunny conditions, water was heated to critical temperature (60 degrees C) in both the FSP systems inactivating more than 3 log (99.9%) of the concentrations of faecal coliform and E. coli to undetectable levels of < 1 CFU/100 mL within 2-5 h exposure to sunlight. However, under cloudy conditions, the two FSP systems did not reduce the concentrations of faecal indicator bacteria to levels of < 1 CFU/100 mL. Nonetheless, sufficient evidence was obtained to show that UV radiation of sunlight plus heat worked synergistically to enhance the inactivation of faecal indicator bacteria. The relative log removal of indicator microorganism in the FSP treated water was total heterotrophic bacteria < C. perfringens < F RNA virus < enterococci < E. coli < faecal coliform. In summary, time of exposure to heat and radiation effects of sunlight were important in disinfecting water by solar units. The data indicated that direct radiation of sunlight worked synergistically with solar heating of the water to disinfect the water. Thus, effective

  12. Methane Emissions in the London Region: Deciphering Regional Sources with Mobile Measurements

    NASA Astrophysics Data System (ADS)

    Zazzeri, G.; Lowry, D.; Fisher, R. E.; France, J. L.; Lanoisellé, M.; Bjorkegren, A.; Nisbet, E. G.

    2014-12-01

    Methane stable isotope analysis, coupled with mole fraction measurement, has been used to link isotopic signature to methane emissions from the leading methane sources in the London region, such as landfills and gas leaks. A mobile Picarro G2301 CRDS analyser was installed in a vehicle, together with an anemometer and a Hemisphere GPS receiver, to measure atmospheric methane mole fractions and their relative location. When methane plumes were located and intercepted, air samples were collected in Tedlar bags, for δ13C-CH4 isotopic analysis by CF-GC-IRMS (Continous Flow-Gas Chromatography-Isotopic Ratio Mass Spectroscopy). This method provides high precision isotopic values, determining δ13C-CH4 to ±0.05 per mil. The bulk signature of the methane plume into the atmosphere from the whole source area was obtained by Keeling plot analysis, and a δ13C-CH4 signature, with the relative uncertainty, allocated to each methane source investigated. The averaged δ13C-CH4 signature for landfill sites around the London region is - 58 ± 3 ‰, whereas the δ13C-CH4 signature for gas leaks is fairly constant at -36 ± 2 ‰, a value characteristic of North Sea supply. The Picarro G2301 analyser was installed also on the roof of King's College London, located in the centre of the city, and connected to an air inlet located 7 meters above roof height. An auto-sampler was connected to the same air inlet and launched remotely when a high nocturnal build up was expected, allowing up to twenty air bags to be collected for methane isotopic analysis over a 24 hour period. The main source contributing to overnight methane build up in central London is fugitive gas, in agreement with inventories. From the isotopic characterisation of urban methane sources and the source mix in London, the contribution to the urban methane budget and the local distribution of the methane sources given in inventories can be validated.

  13. Preliminary design study of an alternate heat source assembly for a Brayton isotope power system

    NASA Technical Reports Server (NTRS)

    Strumpf, H. J.

    1978-01-01

    Results are presented for a study of the preliminary design of an alternate heat source assembly (HSA) intended for use in the Brayton isotope power system (BIPS). The BIPS converts thermal energy emitted by a radioactive heat source into electrical energy by means of a closed Brayton cycle. A heat source heat exchanger configuration was selected and optimized. The design consists of a 10 turn helically wound Hastelloy X tube. Thermal analyses were performed for various operating conditions to ensure that post impact containment shell (PICS) temperatures remain within specified limits. These limits are essentially satisfied for all modes of operation except for the emergency cooling system for which the PICS temperatures are too high. Neon was found to be the best choice for a fill gas for auxiliary cooling system operation. Low cycle fatigue life, natural frequency, and dynamic loading requirements can be met with minor modifications to the existing HSA.

  14. Techno-economic analysis of renewable energy source options for a district heating project

    SciTech Connect

    Ghafghazi, S.; Sowlati, T.; Sokhansanj, Shahabaddine; Melin, Staffan

    2009-09-01

    With the increased interest in exploiting renewable energy sources for district heating applications, the economic comparison of viable options has been considered as an important step in making a sound decision. In this paper, the economic performance of several energy options for a district heating system in Vancouver, British Columbia, is studied. The considered district heating system includes a 10 MW peaking/ backup natural gas boiler to provide about 40% of the annual energy requirement and a 2.5 MW base-load system. The energy options for the base-load system include: wood pellet, sewer heat, and geothermal heat. Present values of initial and operating costs of each system were calculated over 25-year service life of the systems, considering depreciation and salvage as a negative cost item. It was shown that the wood pellet heat producing technologies provided less expensive energy followed by the sewer heat recovery, geothermal and natural gas systems. Among wood pellet technologies, the grate burner was a less expensive option than powder and gasifier technologies. It was found that using natural gas as a fuel source for the peaking/backup system accounted for more than 40% of the heat production cost for the considered district heating center. This is mainly due to the high natural gas prices which cause high operating costs over the service life of the district heating system. Variations in several economic inputs did not change the ranking of the technology options in the sensitivity analysis. However, it was found that the results were more sensitive to changes in operating costs of the system than changes in initial investment. It is economical to utilize wood pellet boilers to provide the base-load energy requirement of district heating systems Moreover, the current business approach to use natural gas systems for peaking and backup in district heating systems could increase the cost of heat production significantly.

  15. COMPARATIVE STUDY AMONG HYBRID GROUND SOURCE HEAT PUMP SYSTEM, COMPLETE GROUND SOURCE HEAT PUMP AND CONVENTIONAL HVAC SYSTEM

    SciTech Connect

    Jiang Zhu; Yong X. Tao

    2011-11-01

    In this paper, a hotel with hybrid geothermal heat pump system (HyGSHP) in the Pensacola is selected and simulated by the transient simulation software package TRNSYS [1]. To verify the simulation results, the validations are conducted by using the monthly average entering water temperature, monthly facility consumption data, and etc. And three types of HVAC systems are compared based on the same building model and HVAC system capacity. The results are presented to show the advantages and disadvantages of HyGSHP compared with the other two systems in terms of energy consumptions, life cycle cost analysis.

  16. Crustal heat transfer in the Taupo Volcanic Zone (New Zealand): comparison with other volcanic arcs and explanatory heat source models

    NASA Astrophysics Data System (ADS)

    Hochstein, M. P.

    1995-10-01

    "anomalous" crustal heat component of the TVZ. Heat generation by focussed plastic deformation within the ductile lithosphere is an alternative mechanism to explain "endogenous crustal heating" which yields heating rates that are also too low by a factor of two, although important parameters (average yield strength of lithosphere and opening rate of the TVZ) are not well known. A further search for a suitable combination of heat source models is required.

  17. Exact Analytical Solution for 3D Time-Dependent Heat Conduction in a Multilayer Sphere with Heat Sources Using Eigenfunction Expansion Method

    PubMed Central

    Dalir, Nemat

    2014-01-01

    An exact analytical solution is obtained for the problem of three-dimensional transient heat conduction in the multilayered sphere. The sphere has multiple layers in the radial direction and, in each layer, time-dependent and spatially nonuniform volumetric internal heat sources are considered. To obtain the temperature distribution, the eigenfunction expansion method is used. An arbitrary combination of homogenous boundary condition of the first or second kind can be applied in the angular and azimuthal directions. Nevertheless, solution is valid for nonhomogeneous boundary conditions of the third kind (convection) in the radial direction. A case study problem for the three-layer quarter-spherical region is solved and the results are discussed.

  18. Potential Source Regions for Elevated Ozone Events in Denmark

    NASA Astrophysics Data System (ADS)

    Mahura, Alexander; Nuterman, Roman; Petrova, Irina

    2010-05-01

    In our study, three Danish measurement sites having the longest time-series of ozone measurements (with a time resolution of 1 hour and starting in early 1990s) records were selected - Ulborg (DK31; 56.28°N, 8.43°E) and Frederiksborg (DK32; 55.97°N, 12.33°E) and Lille Valby (DK41; 55.69°N, 12.13°E) located on Jutland Peninsula and Zealand Island of Denmark, respectively. The measurements with high ozone level (threshold as 150 µg/m3) were selected accounting in total for more than 500 cases for these 3 locations. Note, that among these, 42 (for DK41) and 59 (for DK31 and DK32) cases showed very high ozone concentrations (i.e. above 180 µg/m3). For all these cases, at first, the trajectory modelling approach was applied in order to estimate atmospheric transport pathway of air mass arrival at the measurement sites and potential source regions from where the elevated ozone level can be associated. In our study the Hybrid Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT) model using REANALYSIS meteorological dataset (global, 1948-present) was run to calculate a set of backward trajectories (in with duration of 5 day backward in time and arriving at altitude of 100 m) and divide into groups with respect to potential source regions and dominating atmospheric transport pathways using cluster analysis technique. Analyzing distribution of trajectories (associated with elevated ozone concentrations measured at the Danish sites) as a function of the sector and pathway for the atmospheric transport, the percentage of trajectories had varied among 3 locations and ranged between 11-18% (from the eastern sector), 6-13% (from SW), 10-22% (S), 7-22% (SE), 25-39% (NW), 7-13% (N); with some trajectories having no clear identification. Among trajectories there are those passing through inland (i.e. through the Baltic States, Russia, Poland, Germany, France, Benelux and Scandinavian countries) as well water areas (i.e. transport from the Atlantic Ocean, Baltic

  19. Land surface parameterization for regional surface heat transfer in hilly grassland

    NASA Technical Reports Server (NTRS)

    Sugita, Michiaki; Brutsaert, Wilfried

    1990-01-01

    Radiometrically obtained surface temperature data and wind and temperature data from the atmospheric boundary layer are analyzed to determine the regional surface-heat flux. Monin-Obukhov similarity theory is employed to analyze the wind speed and the relationship between the surface potential temperature and the potential temperature. The radiometric scalar roughness is considered and found to be related to solar elevation and canopy height, although the regional sensible heat flux derived by the similarity theory analysis agrees with measured flux values.

  20. Magma energy: the ultimate heat source for geothermal fields

    SciTech Connect

    Hardee, H.C.

    1982-07-01

    A scientific feasibility study, funded by DOE/Basic Energy Sciences, of extracting energy directly from buried magma sources is discussed. This study has examined the problems of locating and drilling into the magma and then extracting useful quantities of energy from the magma. Theoretical calculations with supporting laboratory and field measurements have been used to show that there are no theoretical or physical barriers that prevent the direct extraction of energy from magma. As a result of this study it has been concluded that magma energy utilization is scientifically feasible.

  1. Thermal Conductivity of Single-Walled Carbon Nanotube with Internal Heat Source Studied by Molecular Dynamics Simulation

    NASA Astrophysics Data System (ADS)

    Li, Yuan-Wei; Cao, Bing-Yang

    2013-12-01

    The thermal conductivity of (5, 5) single-walled carbon nanotubes (SWNTs) with an internal heat source is investigated by using nonequilibrium molecular dynamics (NEMD) simulation incorporating uniform heat source and heat source-and-sink schemes. Compared with SWNTs without an internal heat source, i.e., by a fixed-temperature difference scheme, the thermal conductivity of SWNTs with an internal heat source is much lower, by as much as half in some cases, though it still increases with an increase of the tube length. Based on the theory of phonon dynamics, a function called the phonon free path distribution is defined to develop a simple one-dimensional heat conduction model considering an internal heat source, which can explain diffusive-ballistic heat transport in carbon nanotubes well.

  2. Spatial distribution and source apportionment of PFASs in surface sediments from five lake regions, China.

    PubMed

    Qi, Yanjie; Huo, Shouliang; Xi, Beidou; Hu, Shibin; Zhang, Jingtian; He, Zhuoshi

    2016-01-01

    Perfluoroalkyl substances (PFASs) have been found in environment globally. However, studies on PFAS occurrence in sediments of lakes or reservoirs remain relatively scarce. In this study, two hundred and sixty-two surface sediment samples were collected from forty-eight lakes and two reservoirs all over China. Average PFAS concentrations in surface sediments from each lake or reservoir varied from 0.086 ng/g dw to 5.79 ng/g dw with an average of 1.15 ng/g dw. Among five lake regions, average PFAS concentrations for the lakes from Eastern Plain Region were the highest. Perfluorooctanoic acid, perfluoroundecanoic acid and perfluorooctane sulfonic acid (PFOS) were the predominant PFASs in surface sediments. The significant positive correlations between PFAS concentrations and total organic carbon, total nitrogen and total phosphorus contents in sediments revealed the influences of sedimentary characteristics on PFAS occurrence. A two-dimensional hierarchical cluster analysis heat map was depicted to analyze the possible origins of sediments and individual PFAS. The food-packaging, textile, electroplating, firefighting and semiconductor industry emission sources and the precious metals and coating industry emission sources were identified as the main sources by two receptor models, with contributions of 77.7 and 22.3% to the total concentrations of C4-C14- perfluoroalkyl carboxylic acids and PFOS, respectively. PMID:26947748

  3. Spatial distribution and source apportionment of PFASs in surface sediments from five lake regions, China

    PubMed Central

    Qi, Yanjie; Huo, Shouliang; Xi, Beidou; Hu, Shibin; Zhang, Jingtian; He, Zhuoshi

    2016-01-01

    Perfluoroalkyl substances (PFASs) have been found in environment globally. However, studies on PFAS occurrence in sediments of lakes or reservoirs remain relatively scarce. In this study, two hundred and sixty-two surface sediment samples were collected from forty-eight lakes and two reservoirs all over China. Average PFAS concentrations in surface sediments from each lake or reservoir varied from 0.086 ng/g dw to 5.79 ng/g dw with an average of 1.15 ng/g dw. Among five lake regions, average PFAS concentrations for the lakes from Eastern Plain Region were the highest. Perfluorooctanoic acid, perfluoroundecanoic acid and perfluorooctane sulfonic acid (PFOS) were the predominant PFASs in surface sediments. The significant positive correlations between PFAS concentrations and total organic carbon, total nitrogen and total phosphorus contents in sediments revealed the influences of sedimentary characteristics on PFAS occurrence. A two-dimensional hierarchical cluster analysis heat map was depicted to analyze the possible origins of sediments and individual PFAS. The food-packaging, textile, electroplating, firefighting and semiconductor industry emission sources and the precious metals and coating industry emission sources were identified as the main sources by two receptor models, with contributions of 77.7 and 22.3% to the total concentrations of C4-C14- perfluoroalkyl carboxylic acids and PFOS, respectively. PMID:26947748

  4. An inductively heated hot cavity catcher laser ion source.

    PubMed

    Reponen, M; Moore, I D; Pohjalainen, I; Rothe, S; Savonen, M; Sonnenschein, V; Voss, A

    2015-12-01

    An inductively heated hot cavity catcher has been constructed for the production of low-energy ion beams of exotic, neutron-deficient Ag isotopes. A proof-of-principle experiment has been realized by implanting primary (107)Ag(21+) ions from a heavy-ion cyclotron into a graphite catcher. A variable-thickness nickel foil was used to degrade the energy of the primary beam in order to mimic the implantation depth expected from the heavy-ion fusion-evaporation recoils of N = Z (94)Ag. Following implantation, the silver atoms diffused out of the graphite and effused into the catcher cavity and transfer tube, where they were resonantly laser ionized using a three-step excitation and ionization scheme. Following mass separation, the ions were identified by scanning the frequency of the first resonant excitation step while recording the ion count rate. Ion release time profiles were measured for different implantation depths and cavity temperatures with the mean delay time varying from 10 to 600 ms. In addition, the diffusion coefficients for silver in graphite were measured for temperatures of 1470 K, 1630 K, and 1720 K, from which an activation energy of 3.2 ± 0.3 eV could be determined. PMID:26724021

  5. An inductively heated hot cavity catcher laser ion source

    SciTech Connect

    Reponen, M.; Moore, I. D. Pohjalainen, I.; Savonen, M.; Voss, A.; Rothe, S.; Sonnenschein, V.

    2015-12-15

    An inductively heated hot cavity catcher has been constructed for the production of low-energy ion beams of exotic, neutron-deficient Ag isotopes. A proof-of-principle experiment has been realized by implanting primary {sup 107}Ag{sup 21+} ions from a heavy-ion cyclotron into a graphite catcher. A variable-thickness nickel foil was used to degrade the energy of the primary beam in order to mimic the implantation depth expected from the heavy-ion fusion-evaporation recoils of N = Z {sup 94}Ag. Following implantation, the silver atoms diffused out of the graphite and effused into the catcher cavity and transfer tube, where they were resonantly laser ionized using a three-step excitation and ionization scheme. Following mass separation, the ions were identified by scanning the frequency of the first resonant excitation step while recording the ion count rate. Ion release time profiles were measured for different implantation depths and cavity temperatures with the mean delay time varying from 10 to 600 ms. In addition, the diffusion coefficients for silver in graphite were measured for temperatures of 1470 K, 1630 K, and 1720 K, from which an activation energy of 3.2 ± 0.3 eV could be determined.

  6. An inductively heated hot cavity catcher laser ion source

    NASA Astrophysics Data System (ADS)

    Reponen, M.; Moore, I. D.; Pohjalainen, I.; Rothe, S.; Savonen, M.; Sonnenschein, V.; Voss, A.

    2015-12-01

    An inductively heated hot cavity catcher has been constructed for the production of low-energy ion beams of exotic, neutron-deficient Ag isotopes. A proof-of-principle experiment has been realized by implanting primary 107Ag21+ ions from a heavy-ion cyclotron into a graphite catcher. A variable-thickness nickel foil was used to degrade the energy of the primary beam in order to mimic the implantation depth expected from the heavy-ion fusion-evaporation recoils of N = Z 94Ag. Following implantation, the silver atoms diffused out of the graphite and effused into the catcher cavity and transfer tube, where they were resonantly laser ionized using a three-step excitation and ionization scheme. Following mass separation, the ions were identified by scanning the frequency of the first resonant excitation step while recording the ion count rate. Ion release time profiles were measured for different implantation depths and cavity temperatures with the mean delay time varying from 10 to 600 ms. In addition, the diffusion coefficients for silver in graphite were measured for temperatures of 1470 K, 1630 K, and 1720 K, from which an activation energy of 3.2 ± 0.3 eV could be determined.

  7. The Geysers-Clear Lake geothermal area, California - an updated geophysical perspective of heat sources

    USGS Publications Warehouse

    Stanley, W.D.; Blakely, R.J.

    1995-01-01

    The Geysers-Clear Lake geothermal area encompasses a large dry-steam production area in The Geysers field and a documented high-temperature, high-pressure, water-dominated system in the area largely south of Clear Lake, which has not been developed. An updated view is presented of the geological/geophysical complexities of the crust in this region in order to address key unanswered questions about the heat source and tectonics. Forward modeling, multidimensional inversions, and ideal body analysis of the gravity data, new electromagnetic sounding models, and arguments made from other geophysical data sets suggest that many of the geophysical anomalies have significant contributions from rock property and physical state variations in the upper 7 km and not from "magma' at greater depths. Regional tectonic and magmatic processes are analyzed to develop an updated scenario for pluton emplacement that differs substantially from earlier interpretations. In addition, a rationale is outlined for future exploration for geothermal resources in The Geysers-Clear Lake area. -from Authors

  8. Modular Stirling Radioisotope Power System (SRPS) using an advanced heat source

    NASA Astrophysics Data System (ADS)

    Moul, David S.

    2001-02-01

    The advanced Stirling engine/alternator developed by Stirling Technology Company has potential for a wide range of space applications, at an efficiency comparable to solar cells and triple that of thermoelectric elements. However, the unique design of the Stirling engine requires a concentrated heat input in an annular band which would be optimized with an advanced heat source design. The concentrated heat rejection area of the Stirling engine would also be optimized with the use of a Capillary Pumped Loop to transport the waste heat from the engine. This advanced concept will explore using a Capillary Pumped Loop to transport the waste heat to the mission spacecraft for operational heating. Use of these advanced techniques will allow a specific power approaching 8 We/kg, compared to 5 We for a conventional RTG. .

  9. The role of heat source area on the transition from displacement to mixing flow in natural ventilation

    NASA Astrophysics Data System (ADS)

    Kaye, Nigel; Hunt, Gary

    2007-11-01

    We present a theoretical model for the role of heat source area on the transition from displacement to mixing flow for a naturally ventilated room. We examine the relationship between the existing standard models for natural ventilation of a room with floor and ceiling level vents (Linden et al. 1990 and Gladstone & Woods 2001). We show that the uniform heat distribution model of Gladstone & Woods is the limit of an infinite number of localized heat sources based on the Linden et al. model. We then examine the transition from localized to distributed heat source behaviour as a function of the horizontal extent of the heat source. Our model is based on recent measurements of the plume flow above large area heat sources that suggests the flow rate increases linearly with height. The flow transition is a function of the room vent area scaled on the ceiling height squared and the ratio of the ceiling height to heat source radius. As the heat source radius increases there is a rapid transition from displacement ventilation, driven by localized heat sources, toward mixing ventilation, driven by distributed heat sources. This transition is independent of the floor area of the room implying that for displacement ventilation to be established the heat source(s) need to be small compared to the vertical, as well as horizontal scale of the room.

  10. Can differences in heat flow between east and southern Africa be easily interpreted?: Implications for understanding regional variability in continental heat flow

    NASA Astrophysics Data System (ADS)

    Nyblade, Andrew A.; Pollack, Henry N.

    1993-03-01

    We address the extent to which regional variations in continental heat flow can be interpreted, making use of a heat flow data set from east and southern Africa. The first-order observation deriving from these heat flow measurements is a common pattern characterized in both regions by low heat flow in Archean cratons and higher heat flow in younger mobile belts. Two regional differences between east and southern Africa are superimposed on this common heat flow pattern: (1) heat flow in the Tanzania Craton is about 13 mW m -2 lower than in the Kalahari Craton, and (2) heat flow in the Mozambique Belt in east Africa is about 9 mW m -2 lower than in the southern African mobile belts, within about 250 km of the respective Archean cratons. The differences in heat flow between east and southern Africa suggest that the thermal structure of the lithosphere beneath these regions differs somewhat, and we attempt to resolve these differences in lithospheric thermal structure by examining four explanations that could account for the heat flow observations: (1) diminished heat flow in shallow boreholes in east Africa; (2) less crustal heat production in the regions of lower heat flow; (3) thicker lithosphere beneath the regions of lower heat flow; (4) cooler mantle beneath the areas of lower heat flow. We find it difficult to interpret uniquely the heat flow differences between east and southern Africa because available constraints on crustal heat production, crustal structure, lithospheric thickness and mantle temperatures are insufficient to discriminate among the possible explanations. Hence, extracting significant information about lithospheric thermal structure from regional heat flow variations requires more ancillary geochemical and geophysical information than Africa presently offers.

  11. Regional lightning NOx sources during the TROCCINOX experiment

    NASA Astrophysics Data System (ADS)

    Mari, C.; Chaboureau, J. P.; Pinty, J. P.; Duron, J.; Mascart, P.; Cammas, J. P.; Gheusi, F.; Fehr, T.; Schlager, H.; Roiger, A.; Lichtenstein, M.; Stock, P.

    2006-06-01

    A lightning NOx source (LiNOx) has been implemented in the deep convection scheme of the Meso-NH mesoscale model following a mass-flux formalism coherent with the transport and scavenging of gases inside the convective scheme. No a-priori vertical placement of LiNOx is necessary with this approach. In this approach the vertical transport of NO inside clouds is calculated by the parameterization of deep convective transport, thus eliminating the need for a-priori LiNOx. Once produced inside the convective column, NO molecules are redistributed by updrafts and downdrafts and detrained in the environment when the conditions are favorable. The model was applied to three particular flights during the Tropical Convection, Cirrus and Nitrogen Oxides (TROCCINOX) campaign over the tropical area around Bauru on 3-4 March 2004. The convective activity during the three flights was investigated using brightness temperature at 10.7 µm observed from GOES-12 satellite. The use of a model-to-satellite approach reveals that the simulation appears rather realistic compared to the observations. The diurnal cycle of the simulated brightness temperature, CAPE, number of IC lightning, NO entrainment flux are in phase, with a succession of three marked peaks at 18:00 UTC (15:00 LT). These simulated peaks precede the observed afternoon one by about three hours. Comparison of the simulated NOx with observations along the flight tracks show that the model reproduces well the observed NOx levels when the LiNOx source is applied. The budget of entrainment, detrainment and LiNOx convective fluxes shows that the majority of the NO detrained back to the environment comes from lightning source inside the convective columns. Entrainment of NO from the environment and vertical transport from the boundary layer were not significant during the episode. The troposphere is impacted by detrainment fluxes of LiNOx from 4 km altitude to 16 km with maximum values around 14 km altitude. Detrainment fluxes

  12. Ecological restoration and its effects on a regional climate: the source region of the Yellow River, China.

    PubMed

    Li, Zhouyuan; Liu, Xuehua; Niu, Tianlin; Kejia, De; Zhou, Qingping; Ma, Tianxiao; Gao, Yunyang

    2015-05-19

    The source region of the Yellow River, China, experienced degradation during the 1980s and 1990s, but effective ecological restoration projects have restored the alpine grassland ecosystem. The local government has taken action to restore the grassland area since 1996. Remote sensing monitoring results show an initial restoration of this alpine grassland ecosystem with the structural transformation of land cover from 2000 to 2009 as low- and high-coverage grassland recovered. From 2000 to 2009, the low-coverage grassland area expanded by over 25% and the bare soil area decreased by approximately 15%. To examine the relationship between ecological structure and function, surface temperature (Ts) and evapotranspiration (ET) levels were estimated to study the dynamics of the hydro-heat pattern. The results show a turning point in approximately the year 2000 from a declining ET to a rising ET, eventually reaching the 1990 level of approximately 1.5 cm/day. We conclude that grassland coverage expansion has improved the regional hydrologic cycle as a consequence of ecological restoration. Thus, we suggest that long-term restoration and monitoring efforts would help maintain the climatic adjustment functions of this alpine grassland ecosystem. PMID:25894303

  13. Regional brain heating during microwave exposure (2.06 GHz), warm-water immersion, environmental heating and exercise.

    PubMed

    Walters, T J; Ryan, K L; Belcher, J C; Doyle, J M; Tehrany, M R; Mason, P A

    1998-01-01

    Nonuniform heating may result from microwave (MW) irradiation of tissues and is therefore important to investigate in terms of health and safety issues. Hypothalamic (Thyp), cortical (Tctx), tympanic (Tty), and rectal (Tre) temperatures were measured in rats exposed in the far field, k-polarization (i.e., head pointed toward the transmitter horn and E-field in vertical direction) to two power densities of 2.06 GHz irradiation. The high-power density (HPM) was 1700 mW/cm2 [specific absorption rate (SAR): hypothalamus 1224 W/kg; cortex 493 W/kg]; the low-power density (LPM) was 170 mW/cm2 (SAR: hypothalamus 122.4 W/kg; cortex 49.3 W/kg). The increase (rate-of-rise, in degrees C/s) in Thyp was significantly greater than those in Tctx or Tre when rats were exposed to HPM. LPM produced more homogeneous heating. Quantitatively similar results were observed whether rats were implanted with probes in two brain sites or a single probe in one or the other of the two sites. The qualitative difference between regional brain heating was maintained during unrestrained exposure to HPM in the h-polarization (i.e., body parallel to magnetic field). To compare the temperature changes during MW irradiation with those produced by other modalities of heating, rats were immersed in warm water (44 degrees C, WWI); exposed to a warm ambient environment (50 degrees C, WSED); or exercised on a treadmill (17 m/min 8% grade) in a warm ambient environment (35 degrees C, WEX). WWI produced uniform heating in the regions measured. Similar rates-of-rise occurred among regions following WSED or WEX, thus maintaining the pre-existing gradient between Thyp and Tctx These data indicate that HPM produced a 2-2.5-fold difference in the rate-of-heating within brain regions that were separated by only a few millimeters. In contrast, more homogeneous heating was recorded during LPM or nonmicrowave modalities of heating. PMID:9738525

  14. Electric currents and coronal heating in NOAA active region 6952

    NASA Technical Reports Server (NTRS)

    Metcalf, T. R.; Canfield, R. C.; Hudson, H. S.; Mickey, D. L.; Wulser, J. -P.; Martens, P. C. H.; Tsuneta, S.

    1994-01-01

    We examine the spatial and temporal relationship between coronal structures observed with the soft X-ray telescope (SXT) on board the Yohkoh spacecraft and the vertical electric current density derived from photospheric vector magnetograms obtained using the Stokes Polarimeter at the Mees Solar Observatory. We focus on a single active region: AR 6952 which we observed on 7 days during 1991 December. For 11 independent maps of the vertical electric current density co-aligned with non-flaring X-ray images, we search for a morphological relationship between sites of high vertical current density in the photosphere and enhanced X-ray emission in the overlying corona. We find no compelling spatial or temporal correlation between the sites of vertical current and the bright X-ray structures in this active region.

  15. Thermionic converter with differentially heated cesium-oxygen source and method of operation

    DOEpatents

    Rasor, Ned S.; Riley, David R.; Murray, Christopher S.; Geller, Clint B.

    2000-01-01

    A thermionic converter having an emitter, a collector, and a source of cesium vapor is provided wherein the source of cesium vapor is differentially heated so that said source has a hotter end and a cooler end, with cesium vapor evaporating from said hotter end into the space between the emitter and the collector and with cesium vapor condensing at said cooler end. The condensed cesium vapor migrates through a porous element from the cooler end to the hotter end.

  16. Thermionic converter with differentially heated cesium-oxygen source and method of operation

    SciTech Connect

    Rasor, N.S.; Riley, D.R.; Murray, C.S.; Geller, C.B.

    1998-12-01

    A thermionic converter having an emitter, a collector, and a source of cesium vapor is provided, wherein the source of cesium vapor is differentially heated so that said source has a hotter end and a cooler end, with cesium vapor evaporating from said hotter end into the space between the emitter and the collector and with cesium vapor condensing at said cooler end. The condensed cesium vapor migrates through a porous element from the cooler end to the hotter end.

  17. Generation of Acoustic-Gravity Waves in Ionospheric HF Heating Experiments: Simulating Large-Scale Natural Heat Sources

    NASA Astrophysics Data System (ADS)

    Pradipta, Rezy

    In this thesis, we investigate the potential role played by large-scale anomalous heat sources (e.g. prolonged heat wave events) in generating acoustic-gravity waves (AGWs) that might trigger widespread plasma turbulence in the ionospheric layer. The main hypothesis is that, the thermal gradients associated with the heat wave fronts could act as a source of powerful AGW capable of triggering ionospheric plasma turbulence over extensive areas. In our investigations, first we are going to examine a case study of the summer 2006 North American heat wave event. Our examination of GPS-derived total electron content (TEC) data over the North American sector reveals a quite noticeable increase in the level of daily plasma density fluctuations during the summer 2006 heat wave period. Comparison with the summer 2005 and summer 2007 data further confirms that the observed increase of traveling ionospheric disturbances (TIDs) during the summer 2006 heat wave period was not simply a regular seasonal phenomenon. Furthermore, a series of field experiments had been carried out at the High-frequency Active Auroral Research Program (HAARP) facility in order to physically simulate the process of AGW/TID generation by large-scale thermal gradients in the ionosphere. In these ionospheric HF heating experiments, we create some time-varying artificial thermal gradients at an altitude of 200--300 km above the Earth's surface using vertically-transmitted amplitude-modulated 0-mode HF heater waves. For our experiments, a number of radio diagnostic instruments had been utilized to detect the characteristic signatures of heater-generated AGW/TID. So far, we have been able to obtain several affirmative indications that some artificial AGW/TID are indeed being radiated out from the heated plasma volume during the HAARP-AGW experiments. Based on the experimental evidence, we may conclude that it is certainly quite plausible for large-scale thermal gradients associated with severe heat wave

  18. The structure and heating of the chromosphere-corona transition region

    NASA Technical Reports Server (NTRS)

    Moore, R. L.

    1972-01-01

    The structure and heating (or energy balance) of the transition region and the role of the transition region in the structure and heating of the solar atmosphere as a whole are investigated. The features of the structure of the atmosphere and radiative energy losses of the atmosphere are summarized. A static, planar model of the solar temperature which has a temperature profile representative of the actual solar atmosphere is considered. Then a static, planar model of the transition region which is heated by thermal conduction from the corona and cooled by radiative losses is developed. A general conclusion is that the temperature profile of the transition region and lower corona results primarily from the energy balance of the corona, while the number density is determined by the energy balance of the transition region.

  19. Regional Variation in Residential Heat Pump Water Heater Performance in the U.S.

    SciTech Connect

    Maguire, Jeff; Burch, Jay; Merrigan, Tim; Ong, Sean

    2014-01-01

    Residential heat pump water heaters (HPWHs) have recently re-emerged on the U.S. market, and they have the potential to provide homeowners significant cost and energy savings. However, actual in use performance of a HPWH will vary significantly with climate, installation location, HVAC equipment, and hot water use. To determine the actual energy consumption of a HPWH in different U.S. regions, annual simulations of both 50 and 80 gallon HPWHs as well as a standard electric water heater were performed for over 900 locations across the United States. The simulations included a benchmark home to take into account interactions between the space conditioning equipment and the HPWH and a realistic hot water draw profile. It was found that the HPWH will always save some source energy when compared to a standard electric resistance water heater, although savings varies widely with location. In addition to looking at source energy savings, the breakeven cost (the net installed cost a HPWH would have to have to be a cost neutral replacement for a standard water heater) was also examined. The highest breakeven costs were seen in cases with high energy savings, such as the southeastern U.S., or high energy costs, such as New England and California. While the breakeven cost is higher for 80 gallon units than 50 gallon units, the higher net installed costs of an 80 gallon unit lead to the 50 gallon HPWHs being more likely to be cost effective.

  20. Regional Variation in Residential Heat Pump Water Heater Performance in the U.S.: Preprint

    SciTech Connect

    Maguire, J.; Burch, J.; Merrigan, T.; Ong, S.

    2014-01-01

    Residential heat pump water heaters (HPWHs) have recently reemerged on the U.S. market. These units have the potential to provide homeowners significant cost and energy savings. However, actual in use performance of a HPWH will vary significantly with climate, installation location, HVAC equipment, and hot water use. To determine what actual in use energy consumption of a HPWH may be in different regions of the U.S., annual simulations of both 50 and 80 gallon HPWHs as well as a standard electric water heater were performed for over 900 locations across the U.S. The simulations included a benchmark home to take into account interactions between the space conditioning equipment and the HPWH and a realistic hot water draw profile. It was found that the HPWH will always save some source energy when compared to a standard electric resistance water heater, although savings varies widely with location. In addition to looking at source energy savings, the breakeven cost (the net installed cost a HPWH would have to have to be a cost neutral replacement for a standard water heater) was also examined. The highest breakeven costs were seen in cases with high energy savings, such as the southeastern U.S., or high energy costs, such as New England and California. While the breakeven cost is higher for 80 gallon units than 50 gallon units, the higher net installed costs of an 80 gallon unit lead to the 50 gallon HPWHs being more likely to be cost effective.

  1. Recuperator with microjet technology as a proposal for heat recovery from low-temperature sources

    NASA Astrophysics Data System (ADS)

    Wajs, Jan; Mikielewicz, Dariusz; Fornalik-Wajs, Elżbieta; Bajor, Michał

    2015-12-01

    A tendency to increase the importance of so-called dispersed generation, based on the local energy sources and the working systems utilizing both the fossil fuels and the renewable energy resources is observed nowadays. Generation of electricity on industrial or domestic scale together with production of heat can be obtained for example through employment of the ORC systems. It is mentioned in the EU directive 2012/27/EU for cogenerative production of heat and electricity. For such systems the crucial points are connected with the heat exchangers, which should be small in size but be able to transfer high heat fluxes. In presented paper the prototype microjet heat exchanger dedicated for heat recovery systems is introduced. Its novel construction is described together with the systematical experimental analysis of heat transfer and flow characteristics. Reported results showed high values of the overall heat transfer coefficient and slight increase in the pressure drop. The results of microjet heat exchanger were compared with the results of commercially available compact plate heat exchanger.

  2. Electron Heating in Magnetorotational Instability: Implications for Turbulence Strength in the Outer Regions of Protoplanetary Disks

    NASA Astrophysics Data System (ADS)

    Mori, Shoji; Okuzumi, Satoshi

    2016-01-01

    The magnetorotational instability (MRI) drives vigorous turbulence in a region of protoplanetary disks where the ionization fraction is sufficiently high. It has recently been shown that the electric field induced by the MRI can heat up electrons and thereby affect the ionization balance in the gas. In particular, in a disk where abundant dust grains are present, the electron heating causes a reduction of the electron abundance, thereby preventing further growth of the MRI. By using the nonlinear Ohm's law that takes into account electron heating, we investigate where in protoplanetary disks this negative feedback between the MRI and ionization chemistry becomes important. We find that the “e-heating zone,” the region where the electron heating limits the saturation of the MRI, extends out up to 80 AU in the minimum-mass solar nebula with abundant submicron-sized grains. This region is considerably larger than the conventional dead zone whose radial extent is ∼20 AU in the same disk model. Scaling arguments show that the MRI turbulence in the e-heating zone should have a significantly lower saturation level. Submicron-sized grains in the e-heating zone are so negatively charged that their collisional growth is unlikely to occur. Our present model neglects ambipolar and Hall diffusion, but our estimate shows that ambipolar diffusion would also affect the MRI in the e-heating zone.

  3. Evolved Lithologies and Their Inferred Sources in the Northwestern Procellarum Region of the Moon

    NASA Technical Reports Server (NTRS)

    Jolliff, Bradley L.

    2004-01-01

    Compositional remote sensing from the Lunar Prospector mission reveals the Procellarum- Imbrium region of the Moon, also referred to as the Procellarum KREEP Terrane, to be an area of significant enrichment of heat-producing residua (i.e., Thrich) of the early lunar differentiation. Previous estimates place as much as 60-70% of the whole-Moon content of Th into the crust and as much as 35-40% of the crustal Th content into the Procellarum KREEP Terrane [5], which occupies only approx. 10-15% of the volume of the crust. Although these estimates have significant uncertainty, the correspondence of the enrichment of Th (and other heat producers U and K) in this region is consistent with extended igneous activity, manifested at the surface by extensive basaltic volcanism and subdued topography. Such activity may have extended also to a significant depth, probably including the upper mantle. In this abstract, we present evidence based on Apollo samples for some of the most extensively fractionated lunar rocks types, including a Th-rich mare basalt from Apollo 12, and monzogabbro (also known as monzodiorite), granite, and alkali anorthosite from Apollo 12 and 14 samples. We relate these to likely exposures and sources indicated by compositional remote sensing.

  4. Thermodynamic inspection of concrete using a controlled heat source

    NASA Astrophysics Data System (ADS)

    Milne, James M.

    1990-10-01

    Concrete is not quite such a non-destructable material as many are led to believe. It can deteriorate with time due to changes in the chemistry, the effect of moisture penetration and the corrosion of reinforcing steel bars. Much of this damage occurs relatively close to the surface, sometimes revealed by discolourations or the presence of cracks and sometimes as spallation when the corrosion products of steel cause delamination of the near surface concrete. These effects may occur in good quality concrete but their severity and rapidity of onset may be enhanced by fabrication defects when aggregates may not be to specification or the packing conditions cause porosity. It may thus be months or even years afterwards that these defects come to light. As a consequence a new industry has been formed to inspect concrete structures which may include X-ray equipment, linac accelerators, gamma isotope sources, ultrasonics, radar and of course thermography. Each of these nethods will have their own particular attractive features and merits. But most of these activities tend to be used more as a "fire fighting" service than as one ensuring regular maintenance of critical structures or even as quality control of structures during building. Quite often it seems that Non-destructive Testing is turned into a litigation service for dissatisfied customers and thermography is no stranger to this topic. It is heartening to see that the ASTM organisation in the USA and British Standards are encouraging and developing suitable standards for the inspection of concrete by thermographic techniques.

  5. Heat flow and temperature-depth curves throughout Alaska: finding regions for future geothermal exploration

    NASA Astrophysics Data System (ADS)

    Batir, Joseph F.; Blackwell, David D.; Richards, Maria C.

    2016-06-01

    The objective of this research is to contribute to the understanding of the thermal regime of Alaska and its relationship to geology, regional tectonics, and to suggest potential sites for future geothermal energy production. New heat flow data were collected and are combined with existing published and unpublished data, although large sections of Alaska still lack data. Fault traces were implemented into the heat flow contouring as an additional gridding constraint, to incorporate both heat flow measurements and geology. New heat flow data supported the use of geologic trends in the heat flow mapping procedure, and a heat flow map of Alaska was produced with this added constraint. The multi-input contouring strategy allows production of a map with a regional interpretation of heat flow, in addition to site-specific heat flow and thermal model interpretations in areas with sufficient data density. Utilizing the new heat flow map, temperature-at-depth curves were created for example areas. Temperature-at-depth curves are calculated to 10 km depth for the areas of Anchorage, Fairbanks, Juneau, the Alaska Peninsula, Bristol Bay, and the Copper River Basin. The temperatures-at-depth predicted near the population centers of Anchorage and Juneau are relatively low, limiting the geothermal resource potential. The Fairbanks area temperature estimates are near conventional power production temperatures (150 °C) between 3.5 and 4 km. All data areas, except at Juneau, have temperatures sufficient for low temperature geothermal applications (40 °C) by 2 km. A high heat flow region exists within the Aleutian Volcanic Arc, although new data show heat flow variations from 59 to 120 mW m‑2, so individual geothermal resources within the arc will be irregularly located.

  6. Regional versus Local Sources of aerosols over Cyprus

    NASA Astrophysics Data System (ADS)

    Kleanthous, Savvas; Nicolaou, Panagiota; Theodosi, Christina; Zarmpas, Pavlos; Christofides, Ioannis; Mihalopoulos, Nikolaos

    2013-04-01

    Long term monitoring of PM concentrations in Cyprus reported the occurrence of a significant number of PM exceedances above the limits set by EU legislation and point out the need for abatement strategies. To address these critical issues, mass and chemical composition of daily PM10 aerosol samples were collected at a suburban (Limassol; LIM RES), a natural background site (EMEP site, Ayia Marina) and an urban center (Nicosia, NIC TRA) from January 2010 to December 2010. By considering the chemical composition measured at EMEP as representative of the regional background, the contribution of local sources at both NIC TRA and LIM RES sites can be also estimated. In total, "local" ions account for 1.7 and 2.4 μg m-3, i.e 33 and 48% of the total ionic mass recorded in NIC TRA and LIM RES. Sea salt attained levels of 2.3 ± 1.2 μg m-3, 1.9 ± 1.3 μg m-3 and 3.5 ± 2.3 μg m-3, contributing up to 10, 7 and 11% of the PM10 mass measured at EMEP, NIC TRA and LIM RES, respectively. The local concentrations of OC and EC were equal to 3.3±1.1 μg m-3 and 3.2±1.3 μg m-3 for NIC TRA and 1.70±0.03 μg m-3 and 1.39±0.42 μg m-3 for LIM RES relative to the values measured at the EMEP site. The high EC concentrations in NIC TRA underline the major role of traffic-related emissions. As expected for the natural background site, OC/EC ratio equals 4.84, a strong indicator of secondary organic aerosol (SOA) formation. Whereas in the urban and suburban sites, the OC/EC ratio is lower ranging from 1.46 to 1.84, denoting significant influence from fossil fuel primary emissions in the studied areas. Considering that dust at EMEP is due to "regional" dust, the dust measured at both traffic related sites is the sum of "regional" and "local dust", the second most probably originating from soil dust and car/road abrasion. The "local dust" at NIC TRA and LIM RES accounted for 28% and 21% of the total PM10 mass, whilst regional dust at EMEP of 45%. The temporal variation of "local dust

  7. Heat unit availability for cotton production in the Ogallala Aquifer Region of the United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Expansion in cotton (Gossypium hirsutum L.) production in the Ogallala Aquifer Region can be tied to early maturing varieties, rising energy costs, and declining water levels in the Ogallala Aquifer. However, the feasibility of growing cotton considering the availability of heat units in this region...

  8. Source Tracking Mycobacterium ulcerans Infections in the Ashanti Region, Ghana

    PubMed Central

    Narh, Charles A.; Mosi, Lydia; Quaye, Charles; Dassi, Christelle; Konan, Daniele O.; Tay, Samuel C. K.; de Souza, Dziedzom K.; Boakye, Daniel A.; Bonfoh, Bassirou

    2015-01-01

    Although several studies have associated Mycobacterium ulcerans (MU) infection, Buruli ulcer (BU), with slow moving water bodies, there is still no definite mode of transmission. Ecological and transmission studies suggest Variable Number Tandem Repeat (VNTR) typing as a useful tool to differentiate MU strains from other Mycolactone Producing Mycobacteria (MPM). Deciphering the genetic relatedness of clinical and environmental isolates is seminal to determining reservoirs, vectors and transmission routes. In this study, we attempted to source-track MU infections to specific water bodies by matching VNTR profiles of MU in human samples to those in the environment. Environmental samples were collected from 10 water bodies in four BU endemic communities in the Ashanti region, Ghana. Four VNTR loci in MU Agy99 genome, were used to genotype environmental MU ecovars, and those from 14 confirmed BU patients within the same study area. Length polymorphism was confirmed with sequencing. MU was present in the 3 different types of water bodies, but significantly higher in biofilm samples. Four MU genotypes, designated W, X, Y and Z, were typed in both human and environmental samples. Other reported genotypes were only found in water bodies. Animal trapping identified 1 mouse with lesion characteristic of BU, which was confirmed as MU infection. Our findings suggest that patients may have been infected from community associated water bodies. Further, we present evidence that small mammals within endemic communities could be susceptible to MU infections. M. ulcerans transmission could involve several routes where humans have contact with risk environments, which may be further compounded by water bodies acting as vehicles for disseminating strains. PMID:25612300

  9. Negative hydrogen ion beam extraction from an AC heated cathode driven Bernas-type ion source

    SciTech Connect

    Okano, Y.; Miyamoto, N.; Kasuya, T.; Wada, M.

    2015-04-08

    A plasma grid structure was installed to a Bernas-type ion source used for ion implantation equipment. A negative hydrogen (H{sup −}) ion beam was extracted by an AC driven ion source by adjusting the bias to the plasma grid. The extracted electron current was reduced by positively biasing the plasma grid, while an optimum plasma grid bias voltage for negative ion beam extraction was found to be positive 3 V with respect to the arc chamber. Source operations with AC cathode heating show extraction characteristics almost identical to that with DC cathode heating, except a minute increase in H{sup −} current at higher frequency of cathode heating current.

  10. An evaluation of alternate production methods for Pu-238 general purpose heat source pellets

    SciTech Connect

    Mark Borland; Steve Frank

    2009-06-01

    For the past half century, the National Aeronautics and Space Administration (NASA) has used Radioisotope Thermoelectric Generators (RTG) to power deep space satellites. Fabricating heat sources for RTGs, specifically General Purpose Heat Sources (GPHSs), has remained essentially unchanged since their development in the 1970s. Meanwhile, 30 years of technological advancements have been made in the applicable fields of chemistry, manufacturing and control systems. This paper evaluates alternative processes that could be used to produce Pu 238 fueled heat sources. Specifically, this paper discusses the production of the plutonium-oxide granules, which are the input stream to the ceramic pressing and sintering processes. Alternate chemical processes are compared to current methods to determine if alternative fabrication processes could reduce the hazards, especially the production of respirable fines, while producing an equivalent GPHS product.

  11. Transient thermal stresses due to periodically moving line heat source of composite hollow cylinder

    SciTech Connect

    Chen, L.S.; Chu, H.S. )

    1990-01-01

    The transient thermal stress distribution of a finite composite hollow cylinder, which is heated by a periodically moving line source on its inner boundary and cooled convectively on the outer surface, is analyzed in this paper. The heat sources are assumed to be axisymmetric, moving along the axis of the hollow cylinder with constant velocity. To solve the temperature distribution of the hollow cylinder, the Laplace transform and eigenfunction expansion methods are used. The associated thermal stress distributions are then obtained by solving the thermoelastic displacement function and the Love function. Finally, a numerical scheme, the Fourier series technique, is utilized to calculate the inverse transform. The numerical results of the temperature and thermal stress distribution are presented, which demonstrate the effects of thermal conductivity ratio, shear modulus ratio, Biot number, and period of the moving heat source. 13 refs.

  12. Measurements of the Influence of Integral Length Scale on Stagnation Region Heat Transfer

    NASA Technical Reports Server (NTRS)

    Vanfossen, G. James; Ching, Chang Y.

    1994-01-01

    The purpose was twofold: first, to determine if a length scale existed that would cause the greatest augmentation in stagnation region heat transfer for a given turbulence intensity and second, to develop a prediction tool for stagnation heat transfer in the presence of free stream turbulence. Toward this end, a model with a circular leading edge was fabricated with heat transfer gages in the stagnation region. The model was qualified in a low turbulence wind tunnel by comparing measurements with Frossling's solution for stagnation region heat transfer in a laminar free stream. Five turbulence generating grids were fabricated; four were square mesh, biplane grids made from square bars. Each had identical mesh to bar width ratio but different bar widths. The fifth grid was an array of fine parallel wires that were perpendicular to the axis of the cylindrical leading edge. Turbulence intensity and integral length scale were measured as a function of distance from the grids. Stagnation region heat transfer was measured at various distances downstream of each grid. Data were taken at cylinder Reynolds numbers ranging from 42,000 to 193,000. Turbulence intensities were in the range 1.1 to 15.9 percent while the ratio of integral length scale to cylinder diameter ranged from 0.05 to 0.30. Stagnation region heat transfer augmentation increased with decreasing length scale. An optimum scale was not found. A correlation was developed that fit heat transfer data for the square bar grids to within +4 percent. The data from the array of wires were not predicted by the correlation; augmentation was higher for this case indicating that the degree of isotropy in the turbulent flow field has a large effect on stagnation heat transfer. The data of other researchers are also compared with the correlation.

  13. Demonstration of a non-contact x-ray source using an inductively heated pyroelectric accelerator

    NASA Astrophysics Data System (ADS)

    Klopfer, Michael; Satchouk, Vladimir; Cao, Anh; Wolowiec, Thomas; Alivov, Yahya; Molloi, Sabee

    2015-04-01

    X-ray emission from pyroelectric sources can be produced through non-contact thermal cycling using induction heating. In this study, we demonstrated a proof of concept non-contact x-ray source powered via induction heating. An induction heater operating at 62.5 kHz provided a total of 6.5 W of delivered peak thermal power with 140 V DC of driving voltage. The heat was applied to a ferrous substrate mechanically coupled to a cubic 1 cm3 Lithium Niobate (LiNbO3) pyroelectric crystal maintained in a 3-12 mTorr vacuum. The maximum temperature reached was 175 °C in 86 s of heating. The cooling cycle began immediately after heating and was provided by passive radiative cooling. The total combined cycle time was 250 s. x-ray photons were produced and analyzed in both heating and cooling phases. Maximum photon energies of 59 keV and 55 keV were observed during heating and cooling, respectively. Non-contact devices such as this, may find applications in cancer therapy (brachytherapy), non-destructive testing, medical imaging, and physics education fields.

  14. Energetics of the earth derived from the Kamland observation and radiogenic heat source in the core

    NASA Astrophysics Data System (ADS)

    Ohtani, E.; Enomoto, S.

    2006-05-01

    potassium up to 0.8 wt.percents into molten iron at the condition of 134 GPa and 3,500 K, indicating that the partition coefficient of potassium between iron and silicate is 0.15 at the core-mantle boundary. This result indicates that the core can contain 35 ppm total potassium, which could serve as a heat source in the core for driving the geodynamo. It could be possible to detect the distribution of these elements in the lower mantle and core if we can construct the detector in the oceanic regions such as Hawaii islands far from the continental crust. The development of lower energy neutrino detector is also essential to detect geoneutrinos originated from the decay of radiogenic potassium. [1] T. Araki et al., Nature, 436, 2005; [2] S. Enomoto et al., Earth Planet. Sci. Lett., Submitted, 2006, [3] N. Takafuji et al, [4] T. Kawazoe and E. Ohtani, Phys. Chem. Mineral., 2006 in press; [5] K.T. Wheeler et al., Geochim.Cosmochim. Acta, 2006 in press, [6] N. Hirao et al., G.R.L., in press, 2006.

  15. Particulate matter source apportionment in a village situated in industrial region of Central Europe.

    PubMed

    Pokorná, P; Hovorka, J; Krouzek, J; Hopke, P K

    2013-12-01

    The bilinear receptor model positive matrix factorization (PMF) was used to apportion particulate matter with an aerodynamic diameter of 1-10 microm (PM1-10) sources in a village, Brezno, situated in an industrial region of northern Bohemia in Central Europe. The receptor model analyzed the data sets of 90- and 60-min integrations of PM1-10 mass concentrations and elemental composition for 27 elements. The 14-day sampling campaigns were conducted in the village in summer 2008 and winter 2010. Also, to ensure seasonal and regional representativeness of the data sets recorded in the village, the spatial-temporal variability of the 24-hr PM10 and PM1-10 within 2008-2010 in winter and summer across the multiple sites was evaluated. There were statistically significant interseasonal differences of the 24-hr PM data, but not intrasummer or intrawinter differences of the 24-hr PM1-10 data across the multiple sites. PMF resolved seven sources of PM1-10. They were high-temperature coal combustion; combustion in local heating boilers; marine aerosol; mineral dust; primary biological/wood burning; road dust, car brakes; and gypsum. The main summer factors were assigned to mineral dust (38.2%) and primary biological/wood burning (33.1%). In winter, combustion factors dominated (80%) contribution to PM1-10. The conditional probability function (CPF) helped to identified local sources of PM1-10. The source of marine aerosol from the North Sea and English Channel was indicated by the Hybrid Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT). PMID:24558704

  16. Depth of faulting and ancient heat flows in the Kuiper region of Mercury from lobate scarp topography

    NASA Astrophysics Data System (ADS)

    Egea-González, Isabel; Ruiz, Javier; Fernández, Carlos; Williams, Jean-Pierre; Márquez, Álvaro; Lara, Luisa M.

    2012-01-01

    Mercurian lobate scarps are interpreted to be the surface expressions of thrust faults formed by planetary cooling and contraction, which deformed the crust down to the brittle-ductile transition (BDT) depth at the time of faulting. In this work we have used a forward modeling procedure in order to analyze the relation between scarp topography and fault geometries and depths associated with a group of prominent lobate scarps (Santa Maria Rupes and two unnamed scarps) located in the Kuiper region of Mercury for which Earth-based radar altimetry is available. Also a backthrust associated with one of the lobate scarps has been included in this study. We have obtained best fits for depths of faulting between 30 and 39 km; the results are consistent with the previous results for other lobate scarps on Mercury. The so-derived fault depths have been used to calculate surface heat flows for the time of faulting, taking into account crustal heat sources and a heterogeneous surface temperature due to the variable insolation pattern. Deduced surface heat flows are between 19 and 39 mW m-2 for the Kuiper region, and between 22 and 43 mW m-2 for Discovery Rupes. Both BDT depths and heat flows are consistent with the predictions of thermal history models for the range of time relevant for scarp formation.

  17. Plane Strain Deformation In A Thermoelastic Microelongated Solid With Internal Heat Source

    NASA Astrophysics Data System (ADS)

    Ailawalia, P.; Sachdeva, S. K.; Pathania, D. S.

    2015-12-01

    The purpose of this paper is to study the two dimensional deformation due to an internal heat source in a thermoelastic microelongated solid. A mechanical force is applied along an overlaying elastic layer of thickness h. The normal mode analysis has been applied to obtain the exact expressions for the displacement component, force stress, temperature distribution and microelongation. The effect of the internal heat source on the displacement component, force stress, temperature distribution and microelongation has been depicted graphically for Green-Lindsay (GL) theory of thermoelasticity.

  18. Suppression of cyclotron instability in Electron Cyclotron Resonance ion sources by two-frequency heating

    SciTech Connect

    Skalyga, V.; Izotov, I.; Mansfeld, D.; Kalvas, T.; Koivisto, H.; Komppula, J.; Kronholm, R.; Laulainen, J.; Tarvainen, O.

    2015-08-15

    Multiple frequency heating is one of the most effective techniques to improve the performance of Electron Cyclotron Resonance (ECR) ion sources. The method increases the beam current and average charge state of the extracted ions and enhances the temporal stability of the ion beams. It is demonstrated in this paper that the stabilizing effect of two-frequency heating is connected with the suppression of electron cyclotron instability. Experimental data show that the interaction between the secondary microwave radiation and the hot electron component of ECR ion source plasmas plays a crucial role in mitigation of the instabilities.

  19. Induction heating pure vapor source of high temperature melting point materials on electron cyclotron resonance ion source

    SciTech Connect

    Kutsumi, Osamu; Kato, Yushi; Matsui, Yuuki; Sato, Fuminobu; Iida, Toshiyuki; Kitagawa, Atsushi; Muramatsu, Masayuki; Uchida, Takashi; Yoshida, Yoshikazu

    2010-02-15

    Multicharged ions that are needed are produced from solid pure material with high melting point in an electron cyclotron resonance ion source. We develop an evaporator by using induction heating (IH) with multilayer induction coil, which is made from bare molybdenum or tungsten wire without water cooling and surrounding the pure vaporized material. We optimize the shapes of induction coil and vaporized materials and operation of rf power supply. We conduct experiment to investigate the reproducibility and stability in the operation and heating efficiency. IH evaporator produces pure material vapor because materials directly heated by eddy currents have no contact with insulated materials, which are usually impurity gas sources. The power and the frequency of the induction currents range from 100 to 900 W and from 48 to 23 kHz, respectively. The working pressure is about 10{sup -4}-10{sup -3} Pa. We measure the temperature of the vaporized materials with different shapes, and compare them with the result of modeling. We estimate the efficiency of the IH vapor source. We are aiming at the evaporator's higher melting point material than that of iron.

  20. Investigating the Heating of a Potassium-Doped Aluminosilicate Ion Source Using a 1 Micron Laser

    SciTech Connect

    Schmitt, R C; Meier, W R; Kwan, J W; Abbott, R P; Latkowski, J F

    2004-12-14

    The heavy ion fusion (HIF) program is interested in developing a high brightness ion source for high energy density physics (HEDP) experiments. One possible approach to obtaining higher brightness may be to raise the surface temperature of the ion source just prior to extraction. The current ion source material being studied is a layer of potassium-doped aluminosilicate bonded to a tungsten substrate. It is speculated that if the surface temperature of the source is raised above 1200 C (from a steady-state temperature of 900 C) for time periods on the order of 100's of nanoseconds, current densities of greater than 100 mA/cm{sup 2} of ions may be achievable. Typical aluminosilicate sources produce ion current densities (either K+ or Na+ ions) of {approx}10 mA/cm{sup 2} (at 1100 C). A number of heating methods might be possible, including lasers, diode arrays, and flash lamps. Here we assume laser heating. In this preliminary study, we used the LLNL RadHeat code to model the time-temperature history of the surface when hit by laser pulses and illustrate how RadHeat can be used to optimize the surface temperature response. Also of interest is the temperature history of the interface temperature between the ceramic and the metal layers. This is also investigated.

  1. The Regional Impacts of Cooking and Heating Emissions on Ambient Air Quality and Disease Burden in China.

    PubMed

    Archer-Nicholls, Scott; Carter, Ellison; Kumar, Rajesh; Xiao, Qingyang; Liu, Yang; Frostad, Joseph; Forouzanfar, Mohammad H; Cohen, Aaron; Brauer, Michael; Baumgartner, Jill; Wiedinmyer, Christine

    2016-09-01

    Exposure to air pollution is a major risk factor globally and particularly in Asia. A large portion of air pollutants result from residential combustion of solid biomass and coal fuel for cooking and heating. This study presents a regional modeling sensitivity analysis to estimate the impact of residential emissions from cooking and heating activities on the burden of disease at a provincial level in China. Model surface PM2.5 fields are shown to compare well when evaluated against surface air quality measurements. Scenarios run without residential sector and residential heating emissions are used in conjunction with the Global Burden of Disease 2013 framework to calculate the proportion of deaths and disability adjusted life years attributable to PM2.5 exposure from residential emissions. Overall, we estimate that 341 000 (306 000-370 000; 95% confidence interval) premature deaths in China are attributable to residential combustion emissions, approximately a third of the deaths attributable to all ambient PM2.5 pollution, with 159 000 (142 000-172 000) and 182 000 (163 000-197 000) premature deaths from heating and cooking emissions, respectively. Our findings emphasize the need to mitigate emissions from both residential heating and cooking sources to reduce the health impacts of ambient air pollution in China. PMID:27479733

  2. The radiation belt slot region: A source of energetic electron precipitation in the southern hemisphere polar vortex.

    NASA Astrophysics Data System (ADS)

    Kavanagh, Andrew J.

    2015-04-01

    Energetic electron precipitation at mid-magnetic latitudes in the southern winter hemisphere has the potential to influence regional climate variability. The offset of the magnetic pole in the southern hemisphere means that the footprint of the radiation belt slot region crosses the polar vortex; during large geomagnetic storms the slot region can be filled by electrons, some of which precipitate into the atmosphere. Energetic electron precipitation changes the ion chemistry, generating species that impact the heat balance of the middle atmosphere and potentially influencing regional climate variability when transported in the polar vortex. Energetic precipitation also leads to increased ionization in the mesosphere, which in turn attenuates high frequency radio waves that pass through the region. We present observations of the attenuation of a transmitted signal at 1.98 MHz under the footprint of the radiation belt slot-region during large geomagnetic storms. Measurements from the polar orbiting NOAA POES satellites indicate that the slot-region is being filled by electrons at these times. These observations indicate that the slot region is a source of precipitation that has the potential to impact on the heat balance of the middle atmosphere and below.

  3. Shallow slab detachment as a transient source of heat at midlithospheric depths

    NASA Astrophysics Data System (ADS)

    van de Zedde, D. M. A.; Wortel, M. J. R.

    2001-12-01

    Slab detachment (or breakoff) has been proposed as a cause of temperature-related processes associated with subduction, such as postcollisional magmatism, mineralization, and metamorphism. In this study, we quantitatively investigate the breakoff process and the subsequent thermal evolution of a plate boundary region involving continental collision after a prolonged period of oceanic lithosphere subduction. Our two-dimensional time-dependent thermomechanical modeling shows that the dense, oceanic part of the slab can become detached at depths as shallow as 35 km. The detached part of the slab sinks into the mantle, creating a gap in the lithospheric system which is filled with upwelling hot asthenosphere. The resulting temperature increase in the overlying material can be more than 500°C. It allows for partial melting of the asthenosphere and the overriding metasomatized lithosphere for a timespan of a few millions of years. Crustal anatexis and related magmatism and mineralization can proceed over a considerably longer period. The quantification of the conditions required for shallow slab detachment will contribute to warranted assessments concerning the role of slab detachment (relative to other proposed heat sources, such as tectonically accreted radioactive material) in the geodynamical evolution of former convergent plate boundaries.

  4. Milliwatt generator heat source shelf-life-related pressure-burst capsule evaluations

    SciTech Connect

    Ritchey, B.D.; Eckelmeyer, K.H.; Kilgo, A.C.; McKenzie, B.B.

    1997-10-01

    Three Milliwatt Generator Heat Source (MWGHS) shelf-life-related capsules were pressure-burst tested after thermal aging. Shelf-life capsules PB-08-03 (MC2893) and MPT-11-33 (MC3599) were tested at 1,010 C and capsule PB-07-13 (MC2893) was tested at 1,100 C. Subsequent to pressure-burst testing, each capsule was bubble-leak tested then metallographically examined. Post-mortem evaluation consisted of metallography, microhardness, scanning electron microscopy (SEM), and oxygen and nitrogen analysis. Capsules PB-08-03 and PB-07-13 failed by elevated temperature stress-rupture in the coarse-grained cap to body welds, as has been documented for previous capsules. Pressure-burst testing of capsule MPT-11-33 was terminated prior to failure after 739 hours on test at 1,010 C, however, microscopic examination of the weld indicated that similar failure had began to occur in the interior portion of the capsule to body weld. Evidence was obtained indicating that metallurgical changes occurred during the pressure-burst test performed at 1,100 C. The metallurgical observations of a preferred site for elevated temperature deformation and fracture (the coarse-grained weld region) and structural instability (the property changes during testing at 1,100 C) need to be considered in component lifetime prediction and modeling efforts.

  5. Exergy and Energy analysis of a ground-source heat pump for domestic water heating under simulated occupancy conditions

    SciTech Connect

    Ally, Moonis Raza; Munk, Jeffrey D; Baxter, Van D; Gehl, Anthony C

    2012-01-01

    This paper presents detailed analysis of a water to water ground source heat pump (WW-GSHP) to provide all the hot water needs in a 345 m2 house located in DOE climate zone 4 (mixed-humid). The protocol for hot water use is based on the Building America Research Benchmark Definition (Hendron 2008; Hendron and Engebrecht 2010) which aims to capture the living habits of the average American household and its impact on energy consumption. The entire house was operated under simulated occupancy conditions. Detailed energy and exergy analysis provides a complete set of information on system efficiency and sources of irreversibility, the main cause of wasted energy. The WW-GSHP was sized at 5.275 kW (1.5-ton) for this house and supplied hot water to a 303 L (80 gal) water storage tank. The WW-GSHP shared the same ground loop with a 7.56 kW (2.1-ton) water to air ground source heat pump (WA-GSHP) which provided space conditioning needs to the entire house. Data, analyses, and measures of performance for the WW-GSHP in this paper complements the results of the WA-GSHP published in this journal (Ally, Munk et al. 2012). Understanding the performance of GSHPs is vital if the ground is to be used as a viable renewable energy resource.

  6. GEO2D - Two-Dimensional Computer Model of a Ground Source Heat Pump System

    DOE Data Explorer

    James Menart

    2013-06-07

    This file contains a zipped file that contains many files required to run GEO2D. GEO2D is a computer code for simulating ground source heat pump (GSHP) systems in two-dimensions. GEO2D performs a detailed finite difference simulation of the heat transfer occurring within the working fluid, the tube wall, the grout, and the ground. Both horizontal and vertical wells can be simulated with this program, but it should be noted that the vertical wall is modeled as a single tube. This program also models the heat pump in conjunction with the heat transfer occurring. GEO2D simulates the heat pump and ground loop as a system. Many results are produced by GEO2D as a function of time and position, such as heat transfer rates, temperatures and heat pump performance. On top of this information from an economic comparison between the geothermal system simulated and a comparable air heat pump systems or a comparable gas, oil or propane heating systems with a vapor compression air conditioner. The version of GEO2D in the attached file has been coupled to the DOE heating and cooling load software called ENERGYPLUS. This is a great convenience for the user because heating and cooling loads are an input to GEO2D. GEO2D is a user friendly program that uses a graphical user interface for inputs and outputs. These make entering data simple and they produce many plotted results that are easy to understand. In order to run GEO2D access to MATLAB is required. If this program is not available on your computer you can download the program MCRInstaller.exe, the 64 bit version, from the MATLAB website or from this geothermal depository. This is a free download which will enable you to run GEO2D..

  7. Influence of Turbulence Parameters, Reynolds Number, and Body Shape on Stagnation-Region Heat Transfer

    NASA Technical Reports Server (NTRS)

    Vanfossen, G. James; Simoneau, Robert J.; Ching, Chan Y.

    1994-01-01

    The purpose of the present work was threefold: (1) to determine if a free-stream turbulence length scale existed that would cause the greatest augmentation in stagnation-region heat transfer over laminar levels; (2) to investigate the effect of velocity gradient on stagnation-region heat transfer augmentation by free-stream turbulence; and (3) to develop a prediction tool for stagnation heat transfer in the presence of free-stream turbulence. Heat transfer was measured in the stagnation region of four models with elliptical leading edges that had ratios of major to minor axes of 1:1, 1.5:1, 2.25:1, and 3:1. Five turbulence-generating grids were fabricated; four were square mesh, biplane grids made from square bars. The fifth grid was an array of fine parallel wires that were perpendicular to the model spanwise direction. Heat transfer data were taken at Reynolds numbers ranging from 37 000 to 228 000. Turbulence intensities were in the range of 1.1 to 15.9% while the ratio of integral length scale to leading-edge diameter ranged from 0.05 to 0.30. Stagnation-point velocity gradient was varied by nearly 50%. Stagnation-region heat transfer augmentation was found to increase with decreasing length scale but no optimum length scale was found. Heat transfer augmentation due to turbulence was found to be unaffected by the velocity gradient near the leading edge. A correlation was developed that fit heat transfer data for the square-bar grids to within +/- 4%.

  8. Flow Boiling Heat Transfer to Lithium Bromide Aqueous Solution in Subcooled Region

    NASA Astrophysics Data System (ADS)

    Kaji, Masao; Furukawa, Masahiro; Nishizumi, Takeharu; Ozaki, Shinji; Sekoguchi, Kotohiko

    A theoretical prediction model of the boiling heat transfer coefficient in the subcooled region for water and lithium bromide aqueous solution flowing in a rectangular channel is proposed. In the present heat transfer model, a heat flux is assumed to consist of both the forced convective and the boiling effect components. The forced convective component is evaluated from the empirical correlation of convective heat transfer coefficient for single-phase flow considering the effect of increase of liquid velocity due to net vapor generation. Empirical correlations for determining the heat flux due to the boiling effect and the quality at the onset point of net vapor generation are obtained from the data presented in the first report1). Agreement between the present theoretical prediction and the experimental data is satisfactorily good both for water and lithium bromide aqueous solution.

  9. Critical regions of heat transfer during the nucleate boiling of oxygen under conditions of reduced gravity

    NASA Astrophysics Data System (ADS)

    Kirichenko, Iu. A.; Gladchenko, G. M.; Rusanov, K. V.

    1984-11-01

    Heat transfer during the nucleate boiling of liquid oxygen under conditions of simulated microgravity is investigated experimentally over a wide range of pressures (600-70,000 Pa) and relative accelerations (0.01-1). The objective of the study is to verify some of the existing models for the critical region of heat transfer. Formulas are obtained yielding different acceleration dependences of the critical density of the heat flux for high and low pressures, which is consistent with experimental data on oxygen boiling.

  10. Entrance region heat transfer of a laminar non-Newtonian falling liquid film

    SciTech Connect

    Gorla, R.S.R.; Nee, Y.L. . Dept. of Mechanical Engineering)

    1988-01-01

    There exist several industrial applications in which falling film heat exchangers are used widely. The non-Newtonian fluid falling film shell and tube exchangers are utilized in the food and polymer processing industries. In columns of small length, the falling film flow is laminar when the viscosity of the fluid is high. The authors discuss a study of the heat transfer in one thermal entrance region Ostwald-de-Waele type power of a non-Newtonian laminar falling film. The velocity field is assumed to be fully developed whereas the temperature field is taken as developing. The effect of heat generation by viscous dissipation is included in the analysis.

  11. Safe atmosphere entry of an isotope heat source with a single stable trim attitude at hypersonic speeds

    NASA Technical Reports Server (NTRS)

    Levy, L. L., Jr.; Burns, R. K.

    1972-01-01

    A theoretical investigation has been made to design an isotope heat source capable of satisfying the conflicting thermal requirements of steady-state operation and atmosphere entry. The isotope heat source must transfer heat efficiently to a heat exchange during normal operation with a power system in space, and in the event of a mission abort, it must survive the thermal environment of atmosphere entry and ground impact without releasing radioactive material. A successful design requires a compatible integration of the internal components of the heat source with the external aerodynamic shape. To this end, configurational, aerodynamic, motion, and thermal analyses were coupled and iterated during atmosphere entries at suborbital through superorbital velocities at very shallow and very steep entry angles. Results indicate that both thermal requirements can be satisfied by a heat source which has a single stable aerodynamic orientation at hypersonic speeds. For such a design, the insulation material required to adequately protect the isotope fuel from entry heating need extend only half way around the fuel capsule on the aerodynamically stable (wind-ward) side of the heat source. Thus, a low-thermal-resistance, conducting heat path is provided on the opposite side of the heat source through which heat can be transferred to an adjacent heat exchanger during normal operation without exceeding specified temperature limits.

  12. Stagnation Region Heat Transfer: The Influence of Turbulence Parameters, Reynolds Number and Body Shape

    NASA Technical Reports Server (NTRS)

    Vanfossen, G. James; Simoneau, Robert J.

    1994-01-01

    The effect of velocity gradient on stagnation region heat transfer augmentation by free stream turbulence was investigated. Heat transfer was measured in the stagnation region of four models with elliptical leading edges with ratios of major to minor axes of 1:1, 1.5:1, 2.25:1, and 3:1. Four geometrically similar, square bar, square mesh, biplane grids were used to generate free stream turbulence with different intensities and length. Heat transfer measurements were made for the following ranges of parameters: Reynolds number, based on leading edge diameter, 37,000 to 228,000; dimensionless leading edge velocity gradient, 1.20 to 1.80; turbulence intensity, 1.1 to 15.9%; and length scale to leading edge diameter ratio, 0.05 to 0.30. Stagnation point heat transfer augmentation by free stream turbulence can be predicted using a modified version of a previously developed correlation for a circular leading edge. Heat transfer augmentation was independent of body shape at the stagnation point. The heat transfer distribution down-stream from the stagnation point can be predicted using the normalized laminar heat transfer distribution.

  13. Model of the heat source of the Cerro Prieto magma-hydrothermal system, Baja California, Mexico

    SciTech Connect

    Elders, W.A.; Bird, D.K.; Williams, A.E.; Schiffman, P.; Cox, B.

    1982-08-10

    Earlier studies at Cerro Prieto by UCR have led to the development of a qualitative model for field flow in the geothermal system before it was drilled and perturbed by production. Current efforts are directed towards numerical modelling of heat and mass transfer in the system in this undisturbed state. A two-dimensional model assumes that the heat sources were a single basalt/gabbro intrusion which provided heat to the system as it cooled. After compiling various information on the physical properties of the reservoir, the enthalpy contained in two 1cm thick section across the reservoir orthogonal to each other was calculated. Next various shapes, sizes and depths for the intrusion as initial conditions and boundary conditions for the calculation of heat transfer were considered. A family of numerical models which so far gives the best matches to the conditions observed in the field today have in common a funnel-shaped intrusion with a top 4km wide emplaced at a depth of 5km some 30,000 to 50,000 years ago, providing heat to the geothermal system. Numerical modelling is still in progress. Although none of the models so far computed may be a perfect match for the thermal history of the reservoir, they all indicate that the intrusive heat source is young, close and large.

  14. General-Purpose Heat Source Safety Verification Test series: SVT-7 through SVT-10

    SciTech Connect

    George, T.G.; Pavone, D.

    1985-09-01

    The General-Purpose Heat Source (GPHS) is a modular component of the radioisotope thermoelectric generator that will supply power for the Galileo and Ulysses (formerly ISPM) space missions. The GPHS provides power by transmitting the heat of /sup 238/PuO/sub 2/ ..cap alpha..-decay to an array of thermoelectric elements. Because the possibility of an orbital abort always exists, the heat source was designed and constructed to minimize plutonia release in any accident environment. The Safety Verification Test (SVT) series was formulated to evaluate the effectiveness of GPHS plutonia containment after atmospheric reentry and Earth impact. The first report (covering SVT-1 through SVT-6) described the results of flat and side-on module impacts. This report describes module impacts at angles of 15/sup 0/ and 30/sup 0/.

  15. Heat trap - An optimized far infrared field optics system. [for astronomical sources

    NASA Technical Reports Server (NTRS)

    Harper, D. A.; Hildebrand, R. H.; Winston, R.; Stiening, R.

    1976-01-01

    The article deals with the design and performance of a heat trap IR system designed to maximize the concentration and efficient reception of far IR and submillimeter wavelength radiation. The test object is assumed to be extended and/or viewed at wavelengths much longer than the detector, and the entrance aperture is limited to the size of the telescope Airy diffraction disk. The design of lenses, cavity, bolometers, light collectors, and mirrors for the system is discussed. Advantages and feasibility of arrays of heat traps are considered. Beam patterns, flux concentration, and performance variation with wavelength are dealt with. The heat trap is recommended for sensing all types of far IR sources and particularly for extended far IR sources.-

  16. Multipurpose insulation system for a radioisotope fueled Mini-Brayton Heat Source Assembly

    NASA Technical Reports Server (NTRS)

    Aller, P.; Saylor, W.; Schmidt, G.; Wein, D.

    1976-01-01

    The Mini-Brayton Heat Source Assembly (HSA) consists of a radioisotope fueled heat source, a heat exchanger, a multifoil thermal insulation blanket, and a hermetically sealed housing. The thermal insulation blanket is a multilayer wrap of thin metal foil separated by a sparsely coated oxide. The objectives of the insulation blanket are related to the effective insulation of the HSA during operation, the transfer of the full thermal inventory to the housing when the primary coolant is not flowing, and the transfer of the full thermal inventory to the housing in the event of a flow stoppage of the primary coolant. A description is given of the approaches which have been developed to make it possible for the insulation blanket to meet these requirements.

  17. General-Purpose Heat Source Development: safety test program. Postimpact evaluation, Design Iteration Test 1

    SciTech Connect

    Schonfeld, F.W.

    1984-04-01

    The General-Purpose Heat Source (GPHS) provides power for space missions by transmitting the heat of /sup 238/PuO/sub 2/ decay to thermoelectric elements. Because of the inevitable return of certain missions, the heat source must be designed and constructed to survive re-entry and Earth impact. The Design Iteration Test (DIT) series is part of an ongoing impact test program. The first DIT used a full GPHS module containing two graphite impact shells (GISs); each GIS contained two iridium (0.3 wt%) capsules filled with /sup 238/PuO/sub 2/. It was impacted at 57 m/s and 930/sup 0/C. All four fuel capsules survived and none was breached. However, serious cracking of the iridium-alloy capsules was found; some cracks extended through approx. 70% of the wall thickness. Postimpact analyses of the unit are described with emphasis on weld structure and performance. 51 figures.

  18. FRG sealed isotopic heat sources project (C-229) project management plan

    SciTech Connect

    Metcalf, I.L.

    1997-05-16

    This Project Management Plan defines the cost, scope, schedule, organizational responsibilities, and work breakdown structure for the removal of the Federal Republic of Germany (FRG) Sealed Isotopic Heat Sources from the 324 Building and placed in interim storage at the Central Waste Complex (CWC).

  19. Evaluation and characterization of General Purpose Heat Source girth welds for the Cassini mission

    SciTech Connect

    Lynch, C.M.; Moniz, P.F.; Reimus, M.A.H.

    1998-12-31

    General Purpose Heat Sources (GPHSs) are components of Radioisotopic thermoelectric Generators (RTGs) which provide electric power for deep space missions. Each GPHS consists of a {sup 238}Pu oxide ceramic pellet encapsulated in a welded iridium alloy shell which forms a protective barrier against the release of plutonia in the unlikely event of a launch-pad failure or reentry incident. GPHS fueled clad girth weld flaw detection was paramount to ensuring this safety function, and was accomplished using both destructive and non-destructive evaluation techniques. The first girth weld produced from each welding campaign was metallographically examined for flaws such as incomplete weld penetration, cracks, or porosity which would render a GPHS unacceptable for flight applications. After an acceptable example weld was produced, the subsequently welded heat sources were evaluated non-destructively for flaws using ultrasonic immersion testing. Selected heat sources which failed ultrasonic testing would be radiographed, and/or, destructively evaluated to further characterize and document anomalous indications. Metallography was also performed on impacted heat sources to determine the condition of the welds.

  20. Plasma diagnostics approach to welding heat source/molten pool interaction

    SciTech Connect

    Key, J.F.; McIlwain, M.E.; Isaacson, L.

    1980-01-01

    Plasma diagnostic techniques show that weld fusion zone profile and loss of metal vapors from the molten pool are strongly dependent on both the intensity and distribution of the heat source. These plasma properties, are functions of cathode vertex angle and thermal conductivity of the shielding gas, especially near the anode.

  1. Mantle convection with continental drift and heat source around the mantle transition zone

    NASA Astrophysics Data System (ADS)

    Ichikawa, H.; Kameyama, M.; Kawai, K.

    2012-12-01

    Geological studies have suggested that significant amount of granitic crustal materials have been lost from the surface by the delamination (~1.1 km^3/yr) [1], continental collision (~0.4-0.7 km^3/yr) [1, 2], and subduction at ocean-margin (~2.5-3 km^3/yr) [1, 2]. At ocean-margin subduction zones, most of the granitic materials subducted from the surface are expected to be conveyed through subduction channels by viscous drag to 270km depth [Ichikawa el al., in revision]. If so, then the subducted crustal materials might be expected to be trapped in the mid-mantle owing to the density difference from peridotitic materials induced by the phase transition from coesite to stishovite at 270km depth. In other words, strong heat source materials are most likely to be accumulated around the mantle transition zone, at least, near the plate subduction zones. In this study, we conducted two-dimensional numerical experiments of mantle convection with continental drift and a heat source placed around the mantle transition zone, in order to study the effect of the subducted granitic materials drifting around the mantle transition zone. The simulations deal with a time-dependent convection of fluid under the extended Boussinesq approximation in a model of a two-dimensional rectangular box of 2900km height and 11600km width, where a continent and heat source is imposed. We found that the addition of the heat source considerably reduces the time scale of continental drift. In the absence of the heat source, the resulting time scale is too long compared with that of the so-called supercontinent cycle, where the breakup is induced from a plume generated by an insulating effect of the continent. The heat source also causes massive mechanical mixing especially on the upper mantle. The result suggests that the heat source drifting around mantle transition zone can be a possible candidate inducing the supercontinent cycle in an appropriate time scale. [1] Clift, P. D., P. Vannucchi, and

  2. Neutronics performance and decay heat calculation of a solid target for a spallation neutron source

    NASA Astrophysics Data System (ADS)

    Nio, D.; Ooi, M.; Takenaka, N.; Furusaka, M.; Kawai, M.; Mishima, K.; Kiyanagi, Y.

    2005-08-01

    A solid target is expected to give higher neutron intensity than a liquid target of mercury at a spallation neutron source with a power of around 1 MW. We have studied the neutronic performance of a target-moderator-reflector assembly with a tungsten solid target. It is found that the neutron intensities from moderators were higher in the solid target system than in the mercury liquid target. However, the tungsten target required cladding to prevent tungsten from the corrosion of cooling water. A tungsten target with tantalum cladding has been already developed although tantalum has high decay heat. Therefore, we estimated the decay heat of the target and found that the decay heat of 0.5 mm thick tantalum was still high. We need a thinner tantalum or new cladding materials. It was revealed that adoption of a thinner tantalum or new cladding material such as chrome nitride reduced the decay heat effectively.

  3. Advective heat transport associated to regional Earth degassing in central Apennine (Italy)

    NASA Astrophysics Data System (ADS)

    Cardellini, Carlo; Chiodini, Giovanni; Caliro, Stefano; Chiarabba, Claudio; Frondini, Francesco

    2013-04-01

    The main springs of central Italy Apennines were investigated, in order to compute the amount of heat transported by groundwaters and to compute the fraction of heat due to the geothermal heat flux. The 46 investigated springs represent a significant portion of the permeable structures of the Apennine being characterised by a cumulative flow rate of 130 m3/s, i.e. ~ 50% of the water discharged in this sector of the Apennines. The groundwaters are characterised by relatively low temperatures, but the occurrence of an heat anomaly is evident when the differences between the temperatures of springs and recharge waters are compared with the corresponding altitude difference. A total amount of heat of ~ 2.1 × 109 J/s has been estimated to be transported by these groundwaters. Most of this heat (57%) is given by geothermal warming while the remaining 43% is due to gravitational potential energy dissipation. The computed geothermal warming implies very high heat flux, with values higher than 300 mW/m2, in a large sector of the Apennines which was considered to date be characterised by normal to low conductive heat flux. The same area is affected by high fluxes of CO2 from a deep source and the strict correlation between the geothermal warming and the input of deep CO2-rich fluids is testified by the fact that all the thermally anomalous groundwaters are also affected by the input of deeply derived CO2 contrary to those not thermally anomalous which display any input of deeply derived CO2. This correspondence reasonably suggest the geothermal heat is transported from depth by CO2 rich fluids, which enter the aquifers and mix with infiltrating waters. The amount of geothermal heat transported by central Apennine cold groundwaters is in absolute very high. It results the double than the hydrothermal heat discharge of the US Cascade Range (~1×103 MW) and is about the half of the total heat discharged at Yellowstone, one of the largest hydrothermal system of the world (5-6

  4. Development of a Variable-Speed Residential Air-Source Integrated Heat Pump

    SciTech Connect

    Rice, C Keith; Shen, Bo; Munk, Jeffrey D; Ally, Moonis Raza; Baxter, Van D

    2014-01-01

    A residential air-source integrated heat pump (AS-IHP) is under development in partnership with a U.S. manufacturer. A nominal 10.6 kW (3-ton) cooling capacity variable-speed unit, the system provides both space conditioning and water heating. This multi-functional unit can provide domestic water heating (DWH) in either full condensing (FC) (dedicated water heating or simultaneous space cooling and water heating) or desuperheating (DS) operation modes. Laboratory test data were used to calibrate a vapor-compression simulation model for each mode of operation. The model was used to optimize the internal control options for efficiency while maintaining acceptable comfort conditions and refrigerant-side pressures and temperatures within allowable operating envelopes. Annual simulations were performed with the AS-IHP installed in a well-insulated house in five U.S. climate zones. The AS-IHP is predicted to use 45 to 60% less energy than a DOE minimum efficiency baseline system while meeting total annual space conditioning and water heating loads. Water heating energy use is lowered by 60 to 75% in cold to warmer climates, respectively. Plans are to field test the unit in Knoxville, TN.

  5. Optimization and Thermoeconomics Research of a Large Reclaimed Water Source Heat Pump System

    PubMed Central

    Zhang, Zi-ping; Du, Fang-hui

    2013-01-01

    This work describes a large reclaimed water source heat pump system (RWSHPS) and elaborates on the composition of the system and its design principles. According to the characteristics of the reclaimed water and taking into account the initial investment, the project is divided into two stages: the first stage adopts distributed heat pump heating system and the second adopts the combination of centralized and decentralized systems. We analyze the heating capacity of the RWSHPS, when the phase II project is completed, the system can provide hydronic heating water with the supply and return water temperature of 55°C/15°C and meet the hydronic heating demand of 8 million square meters of residential buildings. We make a thermal economics analysis by using Thermal Economics theory on RWSHPS and gas boiler system, it is known that the RWSHPS has more advantages, compared with the gas boiler heating system; both its thermal efficiency and economic efficiency are relatively high. It provides a reference for future applications of the RWSHPS. PMID:24089607

  6. Development of a High Performance Air Source Heat Pump for the US Market

    SciTech Connect

    Abdelaziz, Omar; Shen, Bo; Gao, Zhiming; Baxter, Van D; Iu, Ipseng

    2011-01-01

    Heat pumps present a significant advantage over conventional residential heating technologies due to higher energy efficiencies and less dependence on imported oil. The US development of heat pumps dates back to the 1930 s with pilot units being commercially available in the 1950 s. Reliable and cost competitive units were available in the US market by the 1960 s. The 1973 oil embargo led to increased interest in heat pumps prompting significant research to improve performance, particularly for cold climate locations. Recent increasing concerns on building energy efficiency and environmental emissions have prompted a new wave of research in heat pump technology with special emphasis on reducing performance degradation at colder outdoor air temperatures. A summary of the advantages and limitations of several performance improvement options sought for the development of high performance air source heat pump systems for cold climate applications is the primary focus of this paper. Some recommendations for a high performance cold climate heat pump system design most suitable for the US market are presented.

  7. Heating mechanisms for intermittent loops in active region cores from AIA/SDO EUV observations

    SciTech Connect

    Cadavid, A. C.; Lawrence, J. K.; Christian, D. J.; Jess, D. B.; Nigro, G.

    2014-11-01

    We investigate intensity variations and energy deposition in five coronal loops in active region cores. These were selected for their strong variability in the AIA/SDO 94 Å intensity channel. We isolate the hot Fe XVIII and Fe XXI components of the 94 Å and 131 Å by modeling and subtracting the 'warm' contributions to the emission. HMI/SDO data allow us to focus on 'inter-moss' regions in the loops. The detailed evolution of the inter-moss intensity time series reveals loops that are impulsively heated in a mode compatible with a nanoflare storm, with a spike in the hot 131 Å signals leading and the other five EUV emission channels following in progressive cooling order. A sharp increase in electron temperature tends to follow closely after the hot 131 Å signal confirming the impulsive nature of the process. A cooler process of growing emission measure follows more slowly. The Fourier power spectra of the hot 131 Å signals, when averaged over the five loops, present three scaling regimes with break frequencies near 0.1 min{sup –1} and 0.7 min{sup –1}. The low frequency regime corresponds to 1/f noise; the intermediate indicates a persistent scaling process and the high frequencies show white noise. Very similar results are found for the energy dissipation in a 2D 'hybrid' shell model of loop magneto-turbulence, based on reduced magnetohydrodynamics, that is compatible with nanoflare statistics. We suggest that such turbulent dissipation is the energy source for our loops.

  8. Sensitivity analysis on the performances of a closed-loop Ground Source Heat Pump

    NASA Astrophysics Data System (ADS)

    Casasso, Alessandro; Sethi, Rajandrea

    2014-05-01

    Ground Source Heat Pumps (GSHP) permit to achieve a significant reduction of greenhouse gas emissions, and the margins for economic saving of this technology are strongly correlated to the long-term sustainability of the exploitation of the heat stored in the soil. The operation of a GSHP over its lifetime should be therefore modelled considering realistic conditions, and a thorough characterization of the physical properties of the soil is essential to avoid large errors of prediction. In this work, a BHE modelling procedure with the finite-element code FEFLOW is presented. Starting from the governing equations of the heat transport in the soil around a GSHP and inside the BHE, the most important parameters are individuated and the adopted program settings are explained. A sensitivity analysis is then carried on both the design parameters of the heat exchanger, in order to understand the margins of improvement of a careful design and installation, and the physical properties of the soil, with the aim of quantifying the uncertainty induced by their variability. The relative importance of each parameter is therefore assessed by comparing the statistical distributions of the fluid temperatures and estimating the energy consumption of the heat pump, and practical conclusions are from these results about the site characterization, the design and the installation of a BHE. References Casasso A., Sethi R., 2014 Efficiency of closed loop geothermal heat pumps: A sensitivity analysis, Renewable Energy 62 (2014), pp. 737-746 Chiasson A.C., Rees S.J., Spitler J.D., 2000, A preliminary assessment of the effects of groundwater flow on closed-loop ground-source heat pump systems, ASHRAE Transactions 106 (2000), pp. 380-393 Delaleux F., Py X., Olives R., Dominguez A., 2012, Enhancement of geothermal borehole heat exchangers performances by improvement of bentonite grouts conductivity, Applied Thermal Engineering 33-34, pp. 92-99 Diao N., Li Q., Fang Z., 2004, Heat transfer in

  9. Dynamic effects on containment of air-curtain fume hood operated with heat source.

    PubMed

    Chen, Jia-Kun; Huang, Rong Fung; Hsin, Pei-Yi

    2012-01-01

    This study focused on the leakage characteristics of the air-curtain fume hood that are subject to the influences of sash movement and walk-by motion while a high temperature heat source was operated in the hood. The flow visualization and trace gas test method were used to investigate the performance of the air-curtain fume hood. An electric heater was placed in the hood to simulate the heat source. The temperature of the heat source installed inside the air-curtain fume hood varied between 180°C and 300°C. Trace gas tests following the dynamic test methods of EN-14175 protocol were employed to measure the spillages of sulfur hexafluoride gas that were released in the hood. When subject to the influence of sash movement at a heat source temperature lower than 260°C, the leakage level was high at the suction velocity V(s) < 8 m/sec but was negligibly small at V(s) > 10 m/sec. When subject to the influence of people walk-by, the leakage level was relatively low at the suction velocity larger than 8 m/sec at sash height H = 50 cm. The height of the sash opening was a crucial parameter for the containment of the air-curtain fume hood. At the sash opening lower than about 25 cm, suction velocity less than or equal to 6 m/sec was enough to make the sulfur hexafluoride leakage less than the threshold value, 0.65 ppm, suggested by the BG Chemie. The air-curtain fume hood presented a great performance to resist the effect of drafts even though there was a high temperature heat source working in the hood. PMID:23009207

  10. Preliminary direct heat geothermal resource assessment of the Tennessee Valley region

    SciTech Connect

    Staub, W.P.

    1980-01-01

    A preliminary appraisal of the direct heat geothermal energy resources of the Tennessee Valley region has been completed. This region includes Kentucky, Tennessee and parts of adjacent states. Intermediate and deep aquifers were selected for study. Basement and Top-of-Knox structure and temperature maps were compiled from oil and gas well data on file at various state geological survey offices. Results of this study indicate that the New Madrid seismic zone is the only area within the region that possesses potential for direct heat utilization. In other areas geothermal energy is either too deep for economical extraction or it will not be able to compete with other local energy resources. The only anomalously high temperature well outside the New Madrid seismic zone was located in the Rome Trough and near the central part of the eastern Kentucky coal basin. Geothermal energy in that region would face strong competition from coal, oil and natural gas.

  11. A HIGH CURRENT DENSITY LI+ ALUMINO-SILICATE ION SOURCE FOR TARGET HEATING EXPERIMENTS

    SciTech Connect

    Roy, Prabir K.; Greenway, Wayne G.; Kwan, Joe W.; Seidl, Peter A.; Waldron, William L.

    2011-03-23

    The NDCX-II accelerator for target heating experiments has been designed to use a large diameter ({approx_equal} 10.9 cm) Li{sup +} doped alumino-silicate source with a pulse duration of 0.5 {micro}s, and beam current of {approx_equal} 93 mA. Characterization of a prototype lithium alumino-silicate sources is presented. Using 6.35mm diameter prototype emitters (coated on a {approx_equal} 75% porous tungsten substrate), at a temperature of {approx_equal} 1275 C, a space-charge limited Li{sup +} beam current density of {approx_equal} 1 mA/cm{sup 2} was measured. At higher extraction voltage, the source is emission limited at around {approx_equal} 1.5 mA/cm{sup 2}, weakly dependent on the applied voltage. The lifetime of the ion source is {approx_equal} 50 hours while pulsing the extraction voltage at 2 to 3 times per minute. Measurements show that the life time of the ion source does not depend only on beam current extraction, and lithium loss may be dominated by neutral loss or by evaporation. The life time of a source is around {ge} 10 hours in a DC mode extraction, and the extracted charge is {approx_equal} 75% of the available Li in the sample. It is inferred that pulsed heating may increase the life time of a source.

  12. Developing a unified parameterization of diabatic heating for regional climate modeling simulations

    NASA Astrophysics Data System (ADS)

    Beltran-Przekurat, A. B.; Pielke, R. A., Sr.; Leoncini, G.; Gabriel, P.

    2009-12-01

    Conventionally, turbulence fluxes, short- and longwave radiative fluxes, and convective and stratiform cloud precipitation atmospheric processes are separately parameterized as a one-dimensional problem. Most of these physical effects occur at spatial scales too small to be explicitly resolved in the models. However, such a separation is not realistic as those processes are three-dimensional and interact with each other. Results from numerical weather prediction and climate models strongly suggest that subgrid-scale parameterizations represent a large source of model errors and sensitivities at a large computational cost. Improving the physical parameterizations and, in addition, reducing the fraction of the total computational time that they require is critical for improving the predictive skill of atmospheric models for both individual model realizations and for ensemble predictions. Our preliminary work presents a new methodology to incorporate parameterizations for use in atmospheric models. The effects of the parameterized physics on the diabatic heating and moistening/drying are incorporated into unified transfer functions, called Universal Look-Up Table (ULUT). The ULUT accepts as inputs the dependent variables and other information that are traditionally inserted into the parameterizations and produces the equivalent temperature and moisture changes that result from summing each parameterization. A similar concept using remotely-sensed data was proposed by Pielke Sr. et al. (2007) [Satellite-based model parameterization of diabatic heating. EOS, 88, 96-97].The major goal is to create a ULUT for the diabatic heating that would be able to reproduce the meteorological fields with the same accuracy as in the original model configuration but at a fraction of the cost. This effort is similar, although much broader in scope, to that of Leoncini et al. (2008, From model based parameterizations to Lookup Tables: An EOF approach. Wea. Forecasting, 23, 1127

  13. Heat transfer in the thermally developing region of a laminar oscillating pipe flow

    NASA Astrophysics Data System (ADS)

    Lee, Dae-Young; Park, Sang-Jin; Tack Ro, Sung

    A theoretical analysis was performed focusing on the heat transfer associated with the laminar oscillating flow in a tube. This situation finds applications in the Stirling engines or regenerative-type refrigerators where the working fluid in the heat exchanger undergoes an oscillatory motion. Such an oscillating flow conceivably entails the thermally developing region, not only because the swept length of working fluid is roughly equal to or longer than the characteristic length of the heat exchanger, but also because the wall temperature changes abruptly along the longitudinal direction. For simulation of the practical heat exchanger composed of cooler and heater, two types of thermal boundary conditions are taken into account; either wall temperature or wall heat flux has a square-wave distribution. It is found that the thermally developing length increases in proportion to the oscillation frequency at slow oscillation but eventually approaches an asymptotic value at high frequency. The local average Nusselt number in the developing region is observed to be inversely proportional to the square root of the distance measured from the thermal discontinuity. Out of the thermally developing region, the local Nusselt number is determined only by the oscillation frequency regardless of axial position.

  14. A new, compact far-infrared source in the W31 region

    NASA Technical Reports Server (NTRS)

    Fazio, G. G.; Lada, C. J.; Kleinmann, D. E.; Wright, E. L.; Ho, P. T. P.; Low, F. J.

    1978-01-01

    In a survey of the W31 region, a compact far-infrared source was detected at the position of the radio continuum source G 10.6-0.4. Associated with this infrared source and in close coincidence with its position is an H II region with a compact core and extended halo as well as OH and H2O masers. An extended molecular cloud, centered on these sources, has also been detected. The compact source and associated masers may be located at the H II region-molecular-cloud interface in a thin shocked layer of neutral gas driven into the molecular cloud by the expansion of the H II region. The compact H II region is depleted of dust and must be surrounded by a very dense shell of dust and gas (hydrogen number density in excess of 200,000 per cu cm). The source probably represents an early stage of stellar evolution.

  15. Waste heat recovery from the European Spallation Source cryogenic helium plants - implications for system design

    SciTech Connect

    Jurns, John M.; Bäck, Harald; Gierow, Martin

    2014-01-29

    The European Spallation Source (ESS) neutron spallation project currently being designed will be built outside of Lund, Sweden. The ESS design includes three helium cryoplants, providing cryogenic cooling for the proton accelerator superconducting cavities, the target neutron source, and for the ESS instrument suite. In total, the cryoplants consume approximately 7 MW of electrical power, and will produce approximately 36 kW of refrigeration at temperatures ranging from 2-16 K. Most of the power consumed by the cryoplants ends up as waste heat, which must be rejected. One hallmark of the ESS design is the goal to recycle waste heat from ESS to the city of Lund district heating system. The design of the cooling system must optimize the delivery of waste heat from ESS to the district heating system and also assure the efficient operation of ESS systems. This report outlines the cooling scheme for the ESS cryoplants, and examines the effect of the cooling system design on cryoplant design, availability and operation.

  16. Waste heat recovery from the European Spallation Source cryogenic helium plants - implications for system design

    NASA Astrophysics Data System (ADS)

    Jurns, John M.; Bäck, Harald; Gierow, Martin

    2014-01-01

    The European Spallation Source (ESS) neutron spallation project currently being designed will be built outside of Lund, Sweden. The ESS design includes three helium cryoplants, providing cryogenic cooling for the proton accelerator superconducting cavities, the target neutron source, and for the ESS instrument suite. In total, the cryoplants consume approximately 7 MW of electrical power, and will produce approximately 36 kW of refrigeration at temperatures ranging from 2-16 K. Most of the power consumed by the cryoplants ends up as waste heat, which must be rejected. One hallmark of the ESS design is the goal to recycle waste heat from ESS to the city of Lund district heating system. The design of the cooling system must optimize the delivery of waste heat from ESS to the district heating system and also assure the efficient operation of ESS systems. This report outlines the cooling scheme for the ESS cryoplants, and examines the effect of the cooling system design on cryoplant design, availability and operation.

  17. Performance and Economic Modeling of Horizontally Drilled Ground-Source Heat Pumps in Select California Climates

    NASA Astrophysics Data System (ADS)

    Wiryadinata, Steven

    Service life modeling was performed to gage the viability of unitary 3.5 kWt, ground-source terminal heat pumps (GTHP) employing horizontal directionally drilled geothermal heat exchangers (GHX) over air-source terminal heat pumps (PTHP) in hotels and motels and residential apartment building sectors in California's coastal and inland climates. Results suggest the GTHP can reduce hourly peak demand for the utility by 7%-25% compared to PTHP, depending on the climate and building type. The annual energy savings, which range from -1% to 5%, are highly dependent on the GTHP pump energy use relative to the energy savings attributed to the difference in ground and air temperatures (DeltaT). In mild climates with small ?T, the pump energy use may overcome any advantage to utilizing a GHX. The majority of total levelized cost savings - ranging from 0.18/ft2 to 0.3/ft 2 - are due to reduced maintenance and lifetime capital cost normally associated with geothermal heat pump systems. Without these reductions (not validated for the GTHP system studied), the GTHP technology does not appear to offer significant advantages over PTHP in the climate zones studied here. The GTHP levelized cost was most sensitive to variations in installed cost and in some cases, energy use (influenced by climate zone choice), which together highlights the importance of climate selection for installation, and the need for larger market penetration of ground-source systems in order to bring down installed costs as the technology matures.

  18. Thulium heat source for high-endurance and high-energy density power systems

    SciTech Connect

    Walter, C.E.; Kammeraad, J.E.; Van Konynenburg, R.; VanSant, J.H.

    1991-05-01

    We are studying the performance characteristics of radioisotope heat source designs for high-endurance and high-energy-density power systems that use thulium-170. Heat sources in the power range of 5--50 kW{sub th} coupled with a power conversion efficiency of {approximately}30%, can easily satisfy current missions for autonomous underwater vehicles. New naval missions will be possible because thulium isotope power systems have a factor of one-to-two hundred higher endurance and energy density than chemical and electrochemical systems. Thulium-170 also has several other attractive features, including the fact that it decays to stable ytterbium-170 with a half-life of four months. For terrestrial applications, refueling on that time scale should be acceptable in view of the advantage of its benign decay. The heat source designs we are studying account for the requirements of isotope production, shielding, and integration with power conversion components. These requirements are driven by environmental and safety considerations. Thulium is present in the form of thin refractory thulia disks that allow power conversion at high peak temperature. We give estimates of power system state points, performance, mass, and volume characteristics. Monte Carlo radiation analysis provides a detailed assessment of shield requirements and heat transfer under normal and distressed conditions is also considered. 11 refs., 7 figs., 4 tabs.

  19. General-Purpose Heat Source: Research and development program: Cold-Process Verification Test Series

    SciTech Connect

    Reimus, M.A.H.; George, T.G.

    1996-06-01

    The General-Purpose Heat Source (GPHS) provides power for space missions by transmitting the heat of {sup 238}Pu decay to an array of thermoelectric elements. Because any space mission could experience a launch abort or return from orbit, the heat source must be designed and constructed to survive credible accident environments. Previous testing conducted in support of the Galileo and Ulysses missions documented the response of GPHSs and individual GPHS capsules fueled with {sup 238}UO{sub 2} ({sup 235}U-depleted) to a variety of explosive overpressure and impact events. In the early 1990s, Los Alamos National Laboratory (LANL) resumed fabrication of {sup 238}UO{sub 2} GPHS pellets. The Cold-Process Verification (CPV) Test Series was designed to compare the response of GPHS heat sources loaded with recently fabricated hot- and cold-pressed {sup 238}UO{sub 2} pellets to the response of urania pellets used in the Galileo and Ulysses performance tests. This report documents eleven bare-capsule impacts and one impact of a fully loaded GPHS module. All of the failures observed in the bare-clad impact tests were similar to failures observed in previous safety tests. No failures occurred in the module impact test.

  20. Thulium heat source for high-endurance and high-energy density power systems

    NASA Astrophysics Data System (ADS)

    Walter, C. E.; Kammeraad, J. E.; Vankonynenburg, R.; Vansant, J. H.

    1991-05-01

    We are studying the performance characteristics of radioisotope heat source designs for high-endurance and high-energy-density power systems that use thulium-170. Heat sources in the power range of 5 to 50 kW(sub th) coupled with a power conversion efficiency of approximately 30 percent, can easily satisfy current missions for autonomous underwater vehicles. New naval missions will be possible because thulium isotope power systems have a factor of one-to-two hundred higher endurance and energy density than chemical and electrochemical systems. Thulium-170 also has several other attractive features, including the fact that it decays to stable ytterbium-170 with a half-life of four months. For terrestrial applications, refueling on that time scale should be acceptable in view of the advantage of its benign decay. The heat source designs we are studying account for the requirements of isotope production, shielding, and integration with power conversion components. These requirements are driven by environmental and safety considerations. Thulium is present in the form of thin refractory thulia disks that allow power conversion at high peak temperature. We give estimates of power system state points, performance, mass, and volume characteristics. Monte Carlo radiation analysis provides a detailed assessment of shield requirements and heat transfer under normal and distressed conditions is also considered.

  1. Improved Bayesian Infrasonic Source Localization for regional infrasound

    NASA Astrophysics Data System (ADS)

    Blom, Philip S.; Marcillo, Omar; Arrowsmith, Stephen J.

    2015-12-01

    The mathematical framework used in the Bayesian Infrasonic Source Localization (BISL) methodology is examined and simplified providing a generalized method of estimating the source location and time for an infrasonic event. The likelihood function describing an infrasonic detection used in BISL has been redefined to include the von Mises distribution developed in directional statistics and propagation-based, physically derived celerity-range and azimuth deviation models. Frameworks for constructing propagation-based celerity-range and azimuth deviation statistics are presented to demonstrate how stochastic propagation modelling methods can be used to improve the precision and accuracy of the posterior probability density function describing the source localization. Infrasonic signals recorded at a number of arrays in the western United States produced by rocket motor detonations at the Utah Test and Training Range are used to demonstrate the application of the new mathematical framework and to quantify the improvement obtained by using the stochastic propagation modelling methods. Using propagation-based priors, the spatial and temporal confidence bounds of the source decreased by more than 40 per cent in all cases and by as much as 80 per cent in one case. Further, the accuracy of the estimates remained high, keeping the ground truth within the 99 per cent confidence bounds for all cases.

  2. Improved Bayesian Infrasonic Source Localization for regional infrasound

    SciTech Connect

    Blom, Philip S.; Marcillo, Omar; Arrowsmith, Stephen J.

    2015-10-20

    The Bayesian Infrasonic Source Localization (BISL) methodology is examined and simplified providing a generalized method of estimating the source location and time for an infrasonic event and the mathematical framework is used therein. The likelihood function describing an infrasonic detection used in BISL has been redefined to include the von Mises distribution developed in directional statistics and propagation-based, physically derived celerity-range and azimuth deviation models. Frameworks for constructing propagation-based celerity-range and azimuth deviation statistics are presented to demonstrate how stochastic propagation modelling methods can be used to improve the precision and accuracy of the posterior probability density function describing the source localization. Infrasonic signals recorded at a number of arrays in the western United States produced by rocket motor detonations at the Utah Test and Training Range are used to demonstrate the application of the new mathematical framework and to quantify the improvement obtained by using the stochastic propagation modelling methods. Moreover, using propagation-based priors, the spatial and temporal confidence bounds of the source decreased by more than 40 per cent in all cases and by as much as 80 per cent in one case. Further, the accuracy of the estimates remained high, keeping the ground truth within the 99 per cent confidence bounds for all cases.

  3. Improved Bayesian Infrasonic Source Localization for regional infrasound

    DOE PAGESBeta

    Blom, Philip S.; Marcillo, Omar; Arrowsmith, Stephen J.

    2015-10-20

    The Bayesian Infrasonic Source Localization (BISL) methodology is examined and simplified providing a generalized method of estimating the source location and time for an infrasonic event and the mathematical framework is used therein. The likelihood function describing an infrasonic detection used in BISL has been redefined to include the von Mises distribution developed in directional statistics and propagation-based, physically derived celerity-range and azimuth deviation models. Frameworks for constructing propagation-based celerity-range and azimuth deviation statistics are presented to demonstrate how stochastic propagation modelling methods can be used to improve the precision and accuracy of the posterior probability density function describing themore » source localization. Infrasonic signals recorded at a number of arrays in the western United States produced by rocket motor detonations at the Utah Test and Training Range are used to demonstrate the application of the new mathematical framework and to quantify the improvement obtained by using the stochastic propagation modelling methods. Moreover, using propagation-based priors, the spatial and temporal confidence bounds of the source decreased by more than 40 per cent in all cases and by as much as 80 per cent in one case. Further, the accuracy of the estimates remained high, keeping the ground truth within the 99 per cent confidence bounds for all cases.« less

  4. Primary source regions of polychlorinated biphenyls (PCBs) measured in the Arctic

    NASA Astrophysics Data System (ADS)

    Ubl, Sandy; Scheringer, Martin; Stohl, Andreas; Burkhart, John F.; Hungerbuhler, Konrad

    2012-12-01

    We investigate the source regions of the three polychlorinated biphenyl congeners (PCBs) 28, 101, and 180 measured at the Arctic stations Alert and Zeppelin, and at Birkenes, which is located in southern Norway. Although the Arctic is remote from the main use areas of these chemicals, PCBs have been found in Arctic air, seawater and biota, which has caused concerns for human and environmental health. We used 20-day backward calculations of the Lagrangian Particle Dispersion Model FLEXPART to identify the origin of air masses associated with the 20% highest and lowest measured PCB concentrations. At Birkenes, high concentrations are clearly associated with air masses arriving from known source regions (primarily in Europe and Russia), whereas low concentrations are correlated with atmospheric transport from regions with low primary emissions. At Zeppelin, the influence from known source regions is also enhanced when high PCB-28 and PCB-101 concentrations were measured. At Alert, in contrast, there is no clear link between high/low PCB concentrations and atmospheric transport from source/non-source regions. Additionally, we combined the atmospheric transport patterns with PCB emission data to identify important source regions and their seasonal variability. For the Arctic stations, Western Russia is the dominant source region for PCB-28 and PCB-101. Central Europe is the most important source region for PCB-180, but sources in the US contribute up to 15% to PCB-180 measured at Alert.

  5. Correlation between heat transfer and fluctuating pressure in the separated region of a bluff body

    NASA Astrophysics Data System (ADS)

    Igarashi, T.

    The paper presents results of a series of experimental studies on heat transfer in the separated region of bluff bodies of various shapes, including a flat plate normal to an airstream, an inclined flat plate, a circular cylinder, and a triangular cylinder. Special attention is given to the correlation between the heat transfer and the rms value of the fluctuating pressure; a new correlation was developed instead of the traditional relation between the average Nusselt number and the Reynolds number. In the new equation, the average heat transfer on the rear face of bluff bodies is correlated with the fluctuating pressure coefficient Cp sub r prime where the constant C ranges from 0.38 and 0.48, depending on the behavior of the shear layer variations for separated regions of bluff bodies.

  6. Modelling nanoflares in active regions and implications for coronal heating mechanisms.

    PubMed

    Cargill, P J; Warren, H P; Bradshaw, S J

    2015-05-28

    Recent observations from the Hinode and Solar Dynamics Observatory spacecraft have provided major advances in understanding the heating of solar active regions (ARs). For ARs comprising many magnetic strands or sub-loops heated by small, impulsive events (nanoflares), it is suggested that (i) the time between individual nanoflares in a magnetic strand is 500-2000 s, (ii) a weak 'hot' component (more than 10(6.6) K) is present, and (iii) nanoflare energies may be as low as a few 10(23) ergs. These imply small heating events in a stressed coronal magnetic field, where the time between individual nanoflares on a strand is of order the cooling time. Modelling suggests that the observed properties are incompatible with nanoflare models that require long energy build-up (over 10 s of thousands of seconds) and with steady heating. PMID:25897093

  7. "Hot" Non-flaring Plasmas in Active Region Cores Heated by Single Nanoflares

    NASA Astrophysics Data System (ADS)

    Barnes, Will Thomas; Cargill, Peter; Bradshaw, Stephen

    2016-05-01

    We use hydrodynamic modeling tools, including a two-fluid development of the EBTEL code, to investigate the properties expected of "hot" (i.e. between 106.7 and 107.2 K) non-flaring plasmas due to nanoflare heating in active regions. Here we focus on single nanoflares and show that while simple models predict an emission measure distribution extending well above 10 MK that is consistent with cooling by thermal conduction, many other effects are likely to limit the existence and detectability of such plasmas. These include: differential heating between electrons and ions, ionization non-equilibrium and, for short nanoflares, the time taken for the coronal density to increase. The most useful temperature range to look for this plasma, often called the "smoking gun" of nanoflare heating, lies between 1 MK and 10 MK. Signatures of the actual heating may be detectable in some instances.

  8. Experimental investigation of refractory metals in the premelting region during fast heating

    NASA Astrophysics Data System (ADS)

    Senchenko, V. N.; Belikov, R. S.; Popov, V. S.

    2015-11-01

    This work demonstrates experimental possibility of investigation of high refractory materials around its melting point, particularly in premelting region with high accuracy. In this article authors describe the developed experimental setup based on rapid resistive self-heating of a sample by a large current pulse generated by a capacitor discharge circuit that allow fast pulse interruption by temperature feedback signal. The sample temperature was measured with a two-channel microsecond radiation pyrometer. Preliminary experiments were conducted on tantalum and molybdenum at heating speed of 108 K/s. The method allows investigating thermophysical properties of refractory conductive materials such as melting temperature, melting heat, specific resistivity, specific enthalpy and specific heat capacity in solid and liquid phase, especially in premelting area.

  9. Modelling nanoflares in active regions and implications for coronal heating mechanisms

    PubMed Central

    Cargill, P. J.; Warren, H. P.; Bradshaw, S. J.

    2015-01-01

    Recent observations from the Hinode and Solar Dynamics Observatory spacecraft have provided major advances in understanding the heating of solar active regions (ARs). For ARs comprising many magnetic strands or sub-loops heated by small, impulsive events (nanoflares), it is suggested that (i) the time between individual nanoflares in a magnetic strand is 500–2000 s, (ii) a weak ‘hot’ component (more than 106.6 K) is present, and (iii) nanoflare energies may be as low as a few 1023 ergs. These imply small heating events in a stressed coronal magnetic field, where the time between individual nanoflares on a strand is of order the cooling time. Modelling suggests that the observed properties are incompatible with nanoflare models that require long energy build-up (over 10 s of thousands of seconds) and with steady heating. PMID:25897093

  10. Linear stability analysis and dynamic simulations of free convection in a differentially heated cavity in the presence of a horizontal magnetic field and a uniform heat source

    NASA Astrophysics Data System (ADS)

    Pelekasis, Nikos A.

    2006-03-01

    The steady state and stability of two-dimensional free convection flow in a square cavity is examined, in the presence of a uniform internal heat source and a uniform magnetic field that is perpendicular to gravity and parallel to an imposed temperature gradient. The finite element method is used for calculating the steady and dynamic state of the system in the parameter space defined by the dimensionless numbers, Gr, Ha, Pr, and S. The trapezoidal rule is used for time integration. Linear stability analysis is performed by solving a generalized eigenvalue problem. The Arnoldi method is used for the calculation of eigenvalues with significant savings in storage and CPU time requirements. The base solution normally exhibits two recirculation regions when the heat production term is large enough. Stability analysis predicts a Hopf bifurcation to a periodic branch. A neutral stability diagram is constructed for a range of values of Ha, Gr, and S for liquid lithium, Pr =0.0321. Internal heat generation, i.e,. increasing S, enhances instability by decreasing the critical value of Grashof, Grcr, determining the onset of the Hopf branch, whereas intensifying the magnetic field, i.e., increasing Ha, stabilizes the flow by increasing Grcr. Dynamic simulations confirm the above structure, identify the oscillatory solution branch as a supercritical Hopf bifurcation for the entire parameter range that was examined, and recover the time constants predicted by stability analysis. As Gr increases or as Ha decreases symmetric arrangement of the two rolls is eliminated and the steady flow configuration loses stability when Gr >Grcr. Subsequently, time periodicity sets in leading to more or less efficient heat removal in terms of lowering or increasing the average cavity temperature, in comparison with the steady flow configuration for the same Gr, depending on whether Ha lies below or above a critical value, respectively, for fixed S and Pr.

  11. Scattering of VLF waves on HF-heated D-region disturbances

    NASA Astrophysics Data System (ADS)

    Lehtinen, N. G.; Cohen, M.; Inan, U. S.

    2009-12-01

    Intense HF radiation from a ground-based facility heats the D-region of the ionosphere. The heating modifies the electron energy distribution function, which is found by solving the kinetic equation at each spatial location. The solution self-consistently takes into account attenuation of HF radiation due to modified HF conductivity. The modification of electron energy distribution leads to the change in the electron-neutral collision frequency and therefore to the change in the conductivity of the disturbed region. Subsequently, we apply the recently developed Stanford FWM (full-wave method) model to the calculation of scattering of VLF transmitter radiation by ionospheric disturbances caused by HF heating, with the utilization of the Born approximation technique. We find the values of the scattered wave magnetic field on the ground to be higher during daytime, due to higher electron density in the D-region. We analyze the validity of Born approximation, and conditions when the second Born approximation calculation is required. We investigate the scattering on ELF/VLF frequency-modulated HF-heated regions and present results of the search for its effects in the experimental data.

  12. DIAGNOSING THE TIME DEPENDENCE OF ACTIVE REGION CORE HEATING FROM THE EMISSION MEASURE. II. NANOFLARE TRAINS

    SciTech Connect

    Reep, J. W.; Bradshaw, S. J.; Klimchuk, J. A. E-mail: stephen.bradshaw@rice.edu

    2013-02-20

    The time dependence of heating in solar active regions can be studied by analyzing the slope of the emission measure distribution coolward of the peak. In a previous study we showed that low-frequency heating can account for 0% to 77% of active region core emission measures. We now turn our attention to heating by a finite succession of impulsive events for which the timescale between events on a single magnetic strand is shorter than the cooling timescale. We refer to this scenario as a 'nanoflare train' and explore a parameter space of heating and coronal loop properties with a hydrodynamic model. Our conclusions are (1) nanoflare trains are consistent with 86% to 100% of observed active region cores when uncertainties in the atomic data are properly accounted for; (2) steeper slopes are found for larger values of the ratio of the train duration {Delta} {sub H} to the post-train cooling and draining timescale {Delta} {sub C}, where {Delta} {sub H} depends on the number of heating events, the event duration and the time interval between successive events ({tau} {sub C}); (3) {tau} {sub C} may be diagnosed from the width of the hot component of the emission measure provided that the temperature bins are much smaller than 0.1 dex; (4) the slope of the emission measure alone is not sufficient to provide information about any timescale associated with heating-the length and density of the heated structure must be measured for {Delta} {sub H} to be uniquely extracted from the ratio {Delta} {sub H}/{Delta} {sub C}.

  13. On the relationship between photospheric footpoint motions and coronal heating in solar active regions

    SciTech Connect

    Van Ballegooijen, A. A.; Asgari-Targhi, M.; Berger, M. A.

    2014-05-20

    Coronal heating theories can be classified as either direct current (DC) or alternating current (AC) mechanisms, depending on whether the coronal magnetic field responds quasi-statically or dynamically to the photospheric footpoint motions. In this paper we investigate whether photospheric footpoint motions with velocities of 1-2 km s{sup –1} can heat the corona in active regions, and whether the corona responds quasi-statically or dynamically to such motions (DC versus AC heating). We construct three-dimensional magnetohydrodynamic models for the Alfvén waves and quasi-static perturbations generated within a coronal loop. We find that in models where the effects of the lower atmosphere are neglected, the corona responds quasi-statically to the footpoint motions (DC heating), but the energy flux into the corona is too low compared to observational requirements. In more realistic models that include the lower atmosphere, the corona responds more dynamically to the footpoint motions (AC heating) and the predicted heating rates due to Alfvén wave turbulence are sufficient to explain the observed hot loops. The higher heating rates are due to the amplification of Alfvén waves in the lower atmosphere. We conclude that magnetic braiding is a highly dynamic process.

  14. Processing summary report: Fabrication of cesium and strontium heat and radiation sources

    SciTech Connect

    Holton, L.K. Jr.; Surma, J.E.; Allen, R.P.; Brouns, R.A.; Bryan, G.H.; Elliott, M.L.; Goles, R.W.; Haun, F.E.; Klein, R.F.; Peters, R.D.

    1989-02-01

    The Pacific Northwest Laboratory (PNL), has produced 30 isotopic heat sources (canisters) for the Federal Republic of Germany (FRG) to be used as part of a repository testing program in the Asse Salt Mine. PNL program work involved the filling, closure, and decontamination of the 30 canisters. The canisters were fabricated (filled) in three separate processing campaigns using the radioactive liquid-fed ceramic melter to produce a borosilicate glass. Within the borosilicate glass matrix radiochemical constituents (/sup 137/Cs and /sup 90/Sr) were immobilized to yield a product with a predetermined decay heat and surface radiation exposure rate.

  15. Application analysis of ground source heat pumps in building space conditioning

    SciTech Connect

    Qian, Hua; Wang, Yungang

    2013-07-01

    The adoption of geothermal energy in space conditioning of buildings through utilizing ground source heat pump (GSHP, also known as geothermal heat pump) has increased rapidly during the past several decades. However, the impacts of the GSHP utilization on the efficiency of heat pumps and soil temperature distribution remained unclear and needs further investigation. This paper presents a novel model to calculate the soil temperature distribution and the coefficient of performance (COP) of GSHP. Different scenarios were simulated to quantify the impact of different factors on the GSHP performance, including heat balance, daily running mode, and spacing between boreholes. Our results show that GSHP is suitable for buildings with balanced cooling and heating loads. It can keep soil temperature at a relatively constant level for more than 10 years. Long boreholes, additional space between boreholes, intermittent running mode will improve the performance of GSHP, but large initial investment is required. The improper design will make the COP of GSHP even lower than traditional heat pumps. Professional design and maintenance technologies are greatly needed in order to promote this promising technology in the developing world.

  16. Analysis and numerical optimization of gas turbine space power systems with nuclear fission reactor heat sources

    NASA Astrophysics Data System (ADS)

    Juhasz, Albert J.

    2005-07-01

    A new three objective optimization technique is developed and applied to find the operating conditions for fission reactor heated Closed Cycle Gas Turbine (CCGT) space power systems at which maximum efficiency, minimum radiator area, and minimum total system mass is achieved. Such CCGT space power systems incorporate a nuclear reactor heat source with its radiation shield; the rotating turbo-alternator, consisting of the compressor, turbine and the electric generator (three phase AC alternator); and the heat rejection subsystem, principally the space radiator, which enables the hot gas working fluid, emanating from either the turbine or a regenerative heat exchanger, to be cooled to compressor inlet conditions. Numerical mass models for all major subsystems and components developed during the course of this work are included in this report. The power systems modeled are applicable to future interplanetary missions within the Solar System and planetary surface power plants at mission destinations, such as our Moon, Mars, the Galilean moons (Io, Europa, Ganymede, and Callisto), or Saturn's moon Titan. The detailed governing equations for the thermodynamic processes of the Brayton cycle have been derived and successfully programmed along with the heat transfer processes associated with cycle heat exchangers and the space radiator. System performance and mass results have been validated against a commercially available non-linear optimization code and also against data from existing ground based power plants.

  17. STEREO ICMEs and their Solar Source Regions Near Solar Minimum

    NASA Astrophysics Data System (ADS)

    Toy, V.; Li, Y.; Luhmann, J. G.; Schroeder, P.; Vourlidas, A.; Jian, L. K.; Russell, C. T.; Galvin, A. B.; Simunac, K.; Acuna, M.; Sauvaud, J. A.; Skoug, R.; Petrie, G.

    2008-12-01

    Although the quiet activity period surrounding the current solar minimum has prevailed since the launch of STEREO in October 2006, there have been at least 9 clear in-situ detections of ICMEs (Interplanetary Coronal Mass Ejections) by one or more spacecraft during the time the imagers were also operating. These observations provide unusually complete data sets for evaluating helio-longitude extent of the ICMEs and for identifying the probable solar cause(s) of the events. In this poster we present information on these ICMEs from the IMPACT and PLASTIC and ACE in-situ investigations, together with solar images from STEREO and SOHO that seem to capture the causative activity at the Sun. We find that even though the Sun was very quiet in '07-'08, with few active regions visible in GONG and SOHO magnetograms, there were numerous CME candidates that erupted through the near-equatorial helmet streamers. Most events could be identified with EUV disk activity as well as a coronagraph CME, even if the associated active region was very small or weak. Old cycle active regions, new and decayed, continued to maintain a warp in the large-scale helmet streamer belt that was a frequent site of the eruptions. However, the warp in the streamer belt may simply indicate that the active region(s) present is(are) sufficiently strong to affect the large scale quiet coronal field structure. Overall we see no gross differences between the solar activity and ICME causes during this and the previous solar activity minimum, when the Streamer belt was less warped due to the existence of stronger solar polar fields.

  18. Alteration mineralogy and geochemistry as an exploration tool for detecting basement heat sources in sedimentary basins

    NASA Astrophysics Data System (ADS)

    Uysal, Tonguc; Gasparon, Massimo; van Zyl, Jacobus; Wyborn, Doone

    2010-05-01

    crystallisation temperatures (150-200°C). Normalised REE patterns of the mostly altered granite samples show a strong negative Ce anomaly, signifying oxidation of trivalent Ce to less soluble tetravalent Ce. Oxygen and hydrogen isotope compositions of illites from the granites and sedimentary rocks are very similar, with d18O = -1.8 per mill to +2.7 per mill; δD = -99 per mill to -121 per mill for granites and d18O = +2.3 per mill to +9.7 per mill, dD = -78 per mill to -119 per mill for sedimentary rocks. The calculated oxygen and hydrogen isotope compositions of fluids in equilibrium with the illites are depleted in 18O and deuterium, comparable to those of waters reported for most high-latitude sedimentary basins. Hence, stable isotope data of alteration minerals in the granite and the overlying sedimentary rocks suggest the operation of a hydrothermal system involving high latitude meteoric waters during extensional tectonism in the Cooper Basin region. Investigation of alteration mineralogy and geochemistry of relatively shallow sedimentary sections (generally intersected in previously drilled petroleum holes) represents a potentially strong tool to evaluate the presence of a geothermal heat source in the basement of sedimentary basins.

  19. Source sector and region contributions to BC and PM2.5 in Central Asia

    DOE PAGESBeta

    Kulkarni, S.; Sobhani, N.; Miller-Schulze, J. P.; Shafer, M. M.; Schauer, J. J.; Solomon, P. A.; Saide, P. E.; Spak, S. N.; Cheng, Y. F.; Denier van der Gon, H. A. C.; et al

    2015-02-18

    Particulate matter (PM) mass concentrations, seasonal cycles, source sector, and source region contributions in Central Asia (CA) are analyzed for the period April 2008–July 2009 using the Sulfur Transport and dEposition Model (STEM) chemical transport model and modeled meteorology from the Weather Research and Forecasting (WRF) model. Predicted aerosol optical depth (AOD) values (annual mean value ~0.2) in CA vary seasonally, with lowest values in the winter. Surface PM2.5 concentrations (annual mean value ~10 μg m-3) also exhibit a seasonal cycle, with peak values and largest variability in the spring/summer, and lowest values and variability in the winter (hourly valuesmore » from 2 to 90 μg m-3). Surface concentrations of black carbon (BC) (mean value ~0.1 μg m-3) show peak values in the winter. The simulated values are compared to surface measurements of AOD as well as PM2.5, PM10, BC, and organic carbon (OC) mass concentrations at two regional sites in Kyrgyzstan (Lidar Station Teplokluchenka (LST) and Bishkek). The predicted values of AOD and PM mass concentrations and their seasonal cycles are fairly well captured. The carbonaceous aerosols are underpredicted in winter, and analysis suggests that the winter heating emissions are underestimated in the current inventory. Dust, from sources within and outside CA, is a significant component of the PM mass and drives the seasonal cycles of PM and AOD. On an annual basis, the power and industrial sectors are found to be the most important contributors to the anthropogenic portion of PM2.5. Residential combustion and transportation are shown to be the most important sectors for BC. Biomass burning within and outside the region also contributes to elevated PM and BC concentrations. The analysis of the transport pathways and the variations in particulate matter mass and composition in CA demonstrates that this region is strategically located to characterize regional and intercontinental transport of

  20. Regularities pertinent to heat transfer between torch gas layers and steam boiler firebox waterwalls. Part I. Geometrical and physical torch model as a source of heat radiation

    NASA Astrophysics Data System (ADS)

    Makarov, A. N.

    2014-09-01

    The progress seen in the 19th-21st centuries in the development of methods for calculating heat transfer in torch furnaces, fireboxes, and combustion chambers is analyzed. Throughout the 20th century, calculations of heat transfer were carried out based on the law for radiation from solid bodies deduced by Y. Stefan and L. Boltzmann. It is shown that the use of this law for calculating heat transfer of a torch (a gaseous source of radiation) in heating furnaces and power-generating installations leads to incorrect results. It is substantiated that there is crisis of methods for calculating heat transfer in torch furnaces and power-generating installations. Geometrical and physical torch models in the form of radiating cylindrical gas volumes as sources of heat radiation are proposed for overcoming this crisis.

  1. Comparison of liquid rocket engine base region heat flux computations using three turbulence models

    NASA Astrophysics Data System (ADS)

    Kumar, Ganesh N.; Griffith, Dwaine O., II; Prendergast, Maurice J.; Seaford, C. M.

    1993-07-01

    The flow in the base region of launch vehicles is characterized by flow separation, flow reversals, and reattachment. Computation of the convective heat flux in the base region and on the nozzle external surface of Space Shuttle Main Engine and Space Transportation Main Engine (STME) is an important part of defining base region thermal environments. Several turbulence models were incorporated in a CFD code and validated for flow and heat transfer computations in the separated and reattaching regions associated with subsonic and supersonic flows over backward facing steps. Heat flux computations in the base region of a single STME engine and a single S1C engine were performed using three different wall functions as well as a renormalization-group based k-epsilon model. With the very limited data available, the computed values are seen to be of the right order of magnitude. Based on the validation comparisons, it is concluded that all the turbulence models studied have predicted the reattachment location and the velocity profiles at various axial stations downstream of the step very well.

  2. Distinct atmospheric patterns and associations with acute heat-induced mortality in five regions of England.

    PubMed

    Petrou, Ilias; Dimitriou, Konstantinos; Kassomenos, Pavlos

    2015-10-01

    The main objective of this paper was to identify possible acute heat-induced summer mortality in five regions of England namely the Yorkshire and the Humber, West Midlands, North East, North West and South East regions and reveal associations with specific air flows. For this purpose, backward air mass trajectories corresponding to daily episodes of increased temperatures were produced and divided to clusters, in order to define atmospheric pathways associated with warm air mass intrusions. A statistically significant at 95 % confidence interval increase in daily total mortality (DTMORT) was observed during the selected episodes at all five regions and thus, heat-induced mortality was indicated. The calculated raise was more intense in the West Midlands, North West and South East regions, whereas the results in the North East and Yorkshire and the Humber regions were less evident. Large fractions of thermal episodes, elevated average temperature values and higher average DTMORT levels were primarily associated with the short-medium range South West (SW) and/or East-South East (E-SE) trajectory clusters, suggesting relations among heat-induced mortality and specific atmospheric circulations. Short-medium length of SW and E-SE airflows, calculated by an application of Haversine formula along the centroid trajectory of each cluster, implies the arrival of slow moving air masses. Atmospheric stagnation could enhance human thermal stress due to low wind speed. PMID:25605407

  3. Distinct atmospheric patterns and associations with acute heat-induced mortality in five regions of England

    NASA Astrophysics Data System (ADS)

    Petrou, Ilias; Dimitriou, Konstantinos; Kassomenos, Pavlos

    2015-10-01

    The main objective of this paper was to identify possible acute heat-induced summer mortality in five regions of England namely the Yorkshire and the Humber, West Midlands, North East, North West and South East regions and reveal associations with specific air flows. For this purpose, backward air mass trajectories corresponding to daily episodes of increased temperatures were produced and divided to clusters, in order to define atmospheric pathways associated with warm air mass intrusions. A statistically significant at 95 % confidence interval increase in daily total mortality (DTMORT) was observed during the selected episodes at all five regions and thus, heat-induced mortality was indicated. The calculated raise was more intense in the West Midlands, North West and South East regions, whereas the results in the North East and Yorkshire and the Humber regions were less evident. Large fractions of thermal episodes, elevated average temperature values and higher average DTMORT levels were primarily associated with the short-medium range South West (SW) and/or East-South East (E-SE) trajectory clusters, suggesting relations among heat-induced mortality and specific atmospheric circulations. Short-medium length of SW and E-SE airflows, calculated by an application of Haversine formula along the centroid trajectory of each cluster, implies the arrival of slow moving air masses. Atmospheric stagnation could enhance human thermal stress due to low wind speed.

  4. Comparison of liquid rocket engine base region heat flux computations using three turbulence models

    NASA Technical Reports Server (NTRS)

    Kumar, Ganesh N.; Griffith, Dwaine O., II; Prendergast, Maurice J.; Seaford, C. M.

    1993-01-01

    The flow in the base region of launch vehicles is characterized by flow separation, flow reversals, and reattachment. Computation of the convective heat flux in the base region and on the nozzle external surface of Space Shuttle Main Engine and Space Transportation Main Engine (STME) is an important part of defining base region thermal environments. Several turbulence models were incorporated in a CFD code and validated for flow and heat transfer computations in the separated and reattaching regions associated with subsonic and supersonic flows over backward facing steps. Heat flux computations in the base region of a single STME engine and a single S1C engine were performed using three different wall functions as well as a renormalization-group based k-epsilon model. With the very limited data available, the computed values are seen to be of the right order of magnitude. Based on the validation comparisons, it is concluded that all the turbulence models studied have predicted the reattachment location and the velocity profiles at various axial stations downstream of the step very well.

  5. Heat Flow in the Salton Trough Revisited and Implications for Regional Tectonics

    NASA Astrophysics Data System (ADS)

    Williams, C.; DeAngelo, J.; Galanis, P.

    2012-12-01

    As part of research into the geothermal energy resources of the Salton Trough, we have assembled a database of 1060 temperature-gradient and heat-flow measurements acquired by the geothermal industry, universities, national labs, and the US Geological Survey (USGS) throughout the region from the early 1970s to the present. In addition to using the data to examine the nature and occurrence of hydrothermal systems, we have estimated the total heat flux through the Trough and investigated relationships between subsurface thermal conditions and the character of faulting and seismicity. Our analysis for the Imperial Valley and other portions of the Salton Trough physiographic province gives an average heat flow of ~160 mW/m2 compared to the 140 mW/m2 average determined by Lachenbruch and others in the last regional study (JGR, v.90, n. B8, 1986). The higher average reflects a larger contribution to the total heat flux from hydrothermal systems that was not recognized in earlier studies due to incomplete spatial coverage. Most of these hydrothermal systems are associated with step-overs and other structural complexities in the fault zones that pass through the region, and the dense coverage of the new heat flow database allows for a detailed examination of the degree to which variations of convective and conductive heat transfer in this region influence, and are influenced by, active tectonic processes. We compared estimated subsurface temperatures from a conductive heat transfer model with the observed depth variation of the upper and lower boundaries of the seismogenic zone along active faults both within and along the margins of the Imperial Valley, and for those areas characterized by average heat flow less than or equal to 150 mW/m2, the base of the seismogenic zone is near the estimated depth of the 400 °C isotherm, a result that is consistent with observations in other seismically active regions. The base of seismicity continues to shallow where heat flow

  6. Evaluation of geothermal energy as a heat source for the oilsands industry in Northern Alberta (Canada)

    NASA Astrophysics Data System (ADS)

    Majorowicz, J. A.; Unsworth, M.; Gray, A.; Nieuwenhuis, G.; Babadagli, T.; Walsh, N.; Weides, S.; Verveda, R.

    2012-12-01

    The extraction and processing of bitumen from the oilsands of Northern Alberta requires very large amounts of heat that is obtained by burning natural gas. At current levels, the gas used represents 6% of Canada's natural gas production. Geothermal energy could potentially provide this heat, thereby reducing both the financial costs and environmental impact of the oilsands industry. The Helmholtz Alberta Initiative is evaluating this application of geothermal energy through an integrated program of geology, geophysics, reservoir simulation and calculations of the cost benefit. A first stage in this evaluation is refining estimates of subsurface temperature beneath Northern Alberta. This has involved three stages: (1) Corrected industrial thermal data have been used to revise estimates of the upper crustal temperatures beneath the oilsands regions in Alberta. The geothermal gradient map produced using heat flow and thermal conductivity for the entire Phanerozoic column suggests that the overall gradient of the entire column is less than the gradients calculated directly from industry measurements. (2) Paleoclimatic corrections must be applied , since this region has experienced a significant increase in surface temperatures since the end of the last ice age causing a perturbation of shallow heat flow. For this reason, estimates of geothermal gradient based on shallow data are not necessarily characteristic of the whole sedimentary column and can lead to errors in temperature prediction at depth. (3) Improved measurements have been made of the thermal conductivity of the crystalline basement rocks (average = 2.9±0.8 W/m K). Thermal conductivity exhibits significant spatial variability and to a large degree controls the temperature conditions in the Precambrian crystalline basement rocks and its heat content at given heat flow-heat generation. When these steps are used to calculate subsurface temperatures, it can be shown that the temperatures required for geothermal

  7. Detailed heat load calculations for the conceptual design of the Advanced Neutron Source reactor

    SciTech Connect

    Wemple, C.A.

    1993-12-01

    A very detailed MCNP model of the Advanced Neutron Source reactor has been developed at Idaho National Engineering Laboratory. All reactor components inside the reflector vessel were included, and al components were highly segmented. Specific heat loads (watts per gram) have been calculated for each segment in the model, and system-integrated total powers are compared with the design value for the total reactor fission power. The calculated results agree very well with the design values. Axial profiles of the heat loads are provided for all components of the reactor. Individual segment statistical uncertainties were limited wherever possible, and the heat loads for all important reflector components have a standard deviation below 5%.

  8. The cryogenic cooling program in high-heat-load optics at the Advanced Photon Source

    SciTech Connect

    Rogers, C.S.

    1993-07-01

    This paper describes some of the aspects of the cryogenic optics program at the Advanced Photon Source (APS). A liquid-nitrogen-cooled, high-vacuum, double crystal monochromator is being fabricated at Argonne National Laboratory (ANL). A pumping system capable of delivering a variable flow rate of up to 10 gallons per minute of pressurized liquid nitrogen and removing 5 kilowatts of x-ray power is also being constructed. This specialized pumping system and monochromator will be used to test the viability of cryogenically cooled, high-heat-load synchrotron optics. It has been determined that heat transfer enhancement will be required for optics used with APS insertion devices. An analysis of a porous-matrix-enhanced monochromator crystal is presented. For the particular case investigated, a heat transfer enhancement factor of 5 to 6 was calculated.

  9. Source component mixing in the regions of arc magma generation

    NASA Astrophysics Data System (ADS)

    Arculus, Richard J.; Powell, Roger

    1986-05-01

    Most recent workers attribute the main features of island arc basalt geochemistry to variable contributions of at least two source components. The major source appears to be the peridotitic wedge of upper mantle overlying the subducted slab, but the nature of the second component and the processes by which the sources become mixed during genesis of arc magmas are in dispute. A metasomatic addition to the wedge resulting from devolatilization in the slab is the simplest explanation of the marked enrichment of the alkali and alkaline earth elements with respect to the rare earths in island arc basalts, together with the variably developed trends in Pb, Sr, and Nd isotopic data toward sedimentary contaminants. However, lack of the correlations between relative degrees of trace element fractionation and radiogenic isotopic ratios expected of such processes requires a more complex explanation. Alternative models that suggest that all of the characteristics of island arc basalts can be accounted for by melting of an intraoceanic, hot spot type of mantle source also face specific difficulties, particularly with regard to the strong depletions of trace high-field-strength elements in arc compared with hot spot magmas. A possible resolution of these specific geochemical difficulties may lie in dynamic transport processes within the wedge linked with the slab through coupled drag, and the marked depression of mantle isotherms in subduction zones. Inefficient escape of melts and subsequent repeated freezing within the overturning wedge can lead to local mineralogic and geochemical heterogeneity of the peridotite overlying the slab. Fluids released from the slab may infiltrate the heterogeneous wedge and preferentially scavenge the alkalis and alkaline earths with respect to the rare earths and high field strength elements from locally enriched portions of the wedge. Incorporation of such metasomatic fluids in renewed melting at shallower but hotter levels within the wedge can

  10. A strongly heated neutron star in the transient z source MAXI J0556-332

    SciTech Connect

    Homan, Jeroen; Remillard, Ronald A.; Fridriksson, Joel K.; Wijnands, Rudy; Cackett, Edward M.; Degenaar, Nathalie; Linares, Manuel

    2014-11-10

    We present Chandra, XMM-Newton, and Swift observations of the quiescent neutron star in the transient low-mass X-ray binary MAXI J0556-332. Observations of the source made during outburst (with the Rossi X-ray Timing Explorer) reveal tracks in its X-ray color-color and hardness-intensity diagrams that closely resemble those of the neutron-star Z sources, suggesting that MAXI J0556-332 had near- or super-Eddington luminosities for a large part of its ∼16 month outburst. A comparison of these diagrams with those of other Z sources suggests a source distance of 46 ± 15 kpc. Fits to the quiescent spectra of MAXI J0556-332 with a neutron-star atmosphere model (with or without a power-law component) result in distance estimates of 45 ± 3 kpc, for a neutron-star radius of 10 km and a mass of 1.4 M {sub ☉}. The spectra show the effective surface temperature of the neutron star decreasing monotonically over the first ∼500 days of quiescence, except for two observations that were likely affected by enhanced low-level accretion. The temperatures we obtain for the fits that include a power law (kT{sub eff}{sup ∞} = 184-308 eV) are much higher than those seen for any other neutron star heated by accretion, while the inferred cooling (e-folding) timescale (∼200 days) is similar to other sources. Fits without a power law yield higher temperatures (kT{sub eff}{sup ∞} = 190-336 eV) and a shorter e-folding time (∼160 days). Our results suggest that the heating of the neutron-star crust in MAXI J0556-332 was considerably more efficient than for other systems, possibly indicating additional or more efficient shallow heat sources in its crust.

  11. R and D -- Seismic report on the influence of the source region on regional seismic waveforms as inferred from modeling

    SciTech Connect

    App, F.N.; Jones, E.M.; Bos, R.J.

    1997-11-01

    The identification of an underground nuclear test from its seismic signal recorded by seismometers at regional distances is one of the fundamental scientific goals of the Comprehensive Test Ban Treaty R and D Program. The work being reported here addresses the issue of event discrimination through the use of computer models that use realistic simulations of nuclear explosions in various settings for the generation of near-regional and regional synthetic seismograms. The study exercises some unique, recently developed computer modeling capabilities that heretofore have not been available for discrimination studies. A variety of source conditions and regional paths are investigated. Under the assumptions of the study, conclusions are: (1) spall, non-linear deformation, and depth-of-burial do not substantially influence the near-regional signal and (2) effects due to basins along the regional path very much dominate over source region geology in influencing the signal at regional distances. These conclusions, however, are relevant only for the frequencies addressed, which span the range from 0.1 to 1 Hz for the regional calculations and 0.1 to 3 Hz for the near-regional calculations. They also are relevant only for the crudely ``China-like`` basin, crust, and mantle properties used in the study. If it is determined that further investigations are required, researchers may use this study as a template for such work.

  12. GPHS motion studies for heat pulse intervals of reentries from gravity-assist trajectories. [General Purpose Heat Source Module (GPHS)

    SciTech Connect

    Lucero, E.F.; Sharbaugh, R.C.

    1990-03-01

    Motion studies of the General Purpose Heat Source Module, GPHS, were conducted in the heat pulse interval associated with entries from earth gravity assist trajectories. The APL six-degree-of-freedom reentry program designated TMAGRA6C was used. The objectives of the studies were to (1) determine the effect of ablation on GPHS motion, and (2) determine whether the GPHS module entering the earth's atmosphere from an earth-gravity-assist trajectory has a preferred orientation during the heat pulse phase of reentry. The results are given in summary form for easy visualization of the initial conditions investigated and to provide a quick-look of the resulting motion. Detail of the motion is also given for the parameters of interest for each case studied. Selected values of initial pitch rate, roll rate, and combinations of these within the range 0[degree] to 1000[degrees]/sec were investigated for initial reentry angles of -7[degrees] (shallow) and -90[degrees] (steep) and initial angles of attack of 0[degree] (broadface to the wind) and 90[degrees]. Although the studies are not exhaustive, a sufficient number of reentry conditions (initial altitude, reentry angle, angle of attack, rotational motion) have been investigated to deduce certain trends. The results also provide information on additional reentry conditions that need to be investigated. The present results show four GPHS orientations that predominate - all with some pitch oscillations and rolling motion. These are: angles of attack, [alpha][sub R] of 0[degree], 30[degrees], 90[degrees] and tumbling. It should be assumed that all these orientations are equally probable because only combinations of two initial reentry angles, [gamma][sub 0], and two values of [alpha][sub R]. have been investigated. Further the probability for any given initial rate on orientation is not known.

  13. THE ROLE OF MAGNETIC TOPOLOGY IN THE HEATING OF ACTIVE REGION CORONAL LOOPS

    SciTech Connect

    Lee, J.-Y.; Reeves, Katharine K.; Korreck, K. E.; Golub, L.; DeLuca, E. E.; Barnes, Graham; Leka, K. D.

    2010-11-10

    We investigate the evolution of coronal loop emission in the context of the coronal magnetic field topology. New modeling techniques allow us to investigate the magnetic field structure and energy release in active regions (ARs). Using these models and high-resolution multi-wavelength coronal observations from the Transition Region and Coronal Explorer and the X-ray Telescope on Hinode, we are able to establish a relationship between the light curves of coronal loops and their associated magnetic topologies for NOAA AR 10963. We examine loops that show both transient and steady emission, and we find that loops that show many transient brightenings are located in domains associated with a high number of separators. This topology provides an environment for continual impulsive heating events through magnetic reconnection at the separators. A loop with relatively constant X-ray and EUV emission, on the other hand, is located in domains that are not associated with separators. This result implies that larger-scale magnetic field reconnections are not involved in heating plasma in these regions, and the heating in these loops must come from another mechanism, such as small-scale reconnections (i.e., nanoflares) or wave heating. Additionally, we find that loops that undergo repeated transient brightenings are associated with separators that have enhanced free energy. In contrast, we find one case of an isolated transient brightening that seems to be associated with separators with a smaller free energy.

  14. Heat pipe array heat exchanger

    DOEpatents

    Reimann, Robert C.

    1987-08-25

    A heat pipe arrangement for exchanging heat between two different temperature fluids. The heat pipe arrangement is in a ounterflow relationship to increase the efficiency of the coupling of the heat from a heat source to a heat sink.

  15. Performance tests of air source heat pumps under frosting conditions. Quality of results

    NASA Astrophysics Data System (ADS)

    Fahlen, P.

    This report focuses on the analysis of uncertainties in research regarding air-source heat pumps. The principles recommended by the Western European Calibration Conference (WECC) are applied and the generated information is condensed in the form of uncertainty budgets. The ensuring discussion, and the Measurement Assurance Program that was applied during the research work are also relevant to general testing of cooling coils, e.g. for air source heat pumps. The general conclusion of the analysis is that the method of determining frost mass by continuous weighing and frost density by inference from pressure drop considerations, which is presented in the report, has the potential to produce results with an accuracy on a par with the best previously used techniques to investigate frosting and defrosting phenomena. Furthermore, the methodology has the distinct advantage of yielding online measuring possibilities and being much less time consuming than traditional techniques.

  16. Performance prediction between horizontal and vertical source heat pump systems for greenhouse heating with the use of artificial neural networks

    NASA Astrophysics Data System (ADS)

    Benli, Hüseyin

    2016-08-01

    This paper presents the suitability of artificial neural networks (ANNs) to predict the performance and comparison between a horizontal and a vertical ground source heat pump system. Performance forecasting is the precondition for the optimal control and energy saving operation of heat pump systems. In this study, performance parameters such as air temperature entering condenser fan-coil unit, air temperature leaving condenser fan-coil unit, and ground temperatures (2 and 60 m) obtained experimental studies are input data; coefficient of performance of system (COPsys) is in output layer. The back propagation learning algorithm with three different variants such as Levenberg-Marguardt, Pola-Ribiere conjugate gradient, and scaled conjugate gradient, and also tangent sigmoid transfer function were used in the network so that the best approach can be found. The results showed that LM with three neurons in the hidden layer is the most suitable algorithm with maximum correlation coefficients R2 of 0.999, minimum root mean square RMS value and low coefficient variance COV. The reported results confirmed that the use of ANN for performance prediction of COPsys,H-V is acceptable in these studies.

  17. Performance prediction between horizontal and vertical source heat pump systems for greenhouse heating with the use of artificial neural networks

    NASA Astrophysics Data System (ADS)

    Benli, Hüseyin

    2015-11-01

    This paper presents the suitability of artificial neural networks (ANNs) to predict the performance and comparison between a horizontal and a vertical ground source heat pump system. Performance forecasting is the precondition for the optimal control and energy saving operation of heat pump systems. In this study, performance parameters such as air temperature entering condenser fan-coil unit, air temperature leaving condenser fan-coil unit, and ground temperatures (2 and 60 m) obtained experimental studies are input data; coefficient of performance of system (COPsys) is in output layer. The back propagation learning algorithm with three different variants such as Levenberg-Marguardt, Pola-Ribiere conjugate gradient, and scaled conjugate gradient, and also tangent sigmoid transfer function were used in the network so that the best approach can be found. The results showed that LM with three neurons in the hidden layer is the most suitable algorithm with maximum correlation coefficients R2 of 0.999, minimum root mean square RMS value and low coefficient variance COV. The reported results confirmed that the use of ANN for performance prediction of COPsys,H-V is acceptable in these studies.

  18. RF Sources for the ITER Ion Cyclotron Heating and Current Drive System

    SciTech Connect

    Hosea, J.; Brunkhorst, C.; Fredd, E.; Goulding, R. H.; Goulding, R. H.; Greenough, N.; Kung, C.; Rasmussen, D. A.; Swain, D. W.; Wilson, J. R.

    2005-10-04

    The RF source requirements for the ITER ion cyclotron (IC) heating and current drive system are very challenging ? 20 MW CW power into an antenna load with a VSWR of up to 2 over the frequency range of 35-65 MHz. For the two present antenna designs under consideration, 8 sources providing 2.5 MW each are to be employed. For these sources, the outputs of two final power amplifiers (FPAs), using the high power CPI 4CM2500KG tube, are combined with a 180? hybrid combiner to easily meet the ITER IC source requirements ? 2.5 MW is supplied at a VSWR of 2 at ? 70% of the maximum tube power available in class B operation. The cylindrical cavity configuration for the FPAs is quite compact so that the 8 combined sources fit into the space allocated at the ITER site with room to spare. The source configuration is described in detail and its projected operating power curves are presented. Although the CPI tube has been shown to be stable under high power operating conditions on many facilities, a test of the combined FPA source arrangement is in preparation using existing high power 30 MHz amplifiers to assure that this configuration can be made robustly stable for all phases at a VSWR up to 2. The possibility of using 12 sources to feed a suitably modified antenna design is also discussed in the context of providing flexibility for specifying the final IC antenna design.

  19. Assessing climate change and heat stress responses in the Tarai region of Nepal.

    PubMed

    Pradhan, Bandana; Shrestha, Shailendra; Shrestha, Ranjana; Pradhanang, Sadhana; Kayastha, Birendra; Pradhan, Pushkar

    2013-01-01

    This paper intends to analyse responses of the working people to heat stress in Nepal's Tarai region. Here, the heat stress responses refer to the working environments- indoor and outdoor settings, prevailing diseases, and adaptive measures by the workers. Data were gathered from the sample households by using household survey, observation, and informal discussions. Environmental conditions in terms of heat exposure in the working areas have been measured with heat index, humidity index, and WBGT, based on the HOTHAPS approach. The findings are that: the average temperature during the peak hot months reached to over 39°C and the environmental conditions in the selected factories during the hot summer months were too hot to the workers to work continuously during the day, where there was inadequacy of facilities to combat against the hot. Males were more exposed than females to the heat due to heavy type of works in outdoor settings. Few workers found to have adapted coping measures such as shift in working time, wearing thin cotton clothes, etc but they were inadequate against the heat stress. More quantitative measurements of workers' health effects and productivity loss will be of interest for future works. PMID:23411760

  20. An investigation of potential regional and local source regions affecting fine particulate matter concentrations in Delhi, India.

    PubMed

    Ghosh, Saikat; Biswas, Jhumoor; Guttikunda, Sarath; Roychowdhury, Soma; Nayak, Mugdha

    2015-02-01

    In this study, potential regional and local sources influencing PM2.5 (particulate matter with an aerodynamic diameter >2.5 μm) concentrations in Delhi, India, are identified and their possible impact evaluated through diverse approaches based on study of variability of synoptic and local airflow patterns that transport aerosol concentrations from these emission sources to an urban receptor site in Delhi, India. Trajectory clustering of 72-hr and 48-hr back trajectories simulated at arrival heights of 500 m and 100 m, respectively, every hour for representative years 2008-2010 are used to assess the relative influence of long-distance, regional, and subregional sources on this site. Nonparametric statistical procedures are employed on trajectory clusters to better delineate various distinct regional pollutant source regions. Trajectory clustering and concentration-weighted trajectory (CWT) analyses indicate that regional and subregional PM2.5 emission sources in neighboring country of Pakistan and adjacent states of Punjab, Haryana, and Uttar Pradesh contribute significantly to the total surplus of aerosol concentrations in the Delhi region. Conditional probability function and Bayesian approach used to identify local source regions have established substantial influence from highly urbanized satellite towns located southwest (above 25%) and southeast (above 45%) of receptor location. There is significant seasonal variability in synoptic and local air circulation patterns, which is discerned in variability in seasonal concentrations. Mean of daily averaged PM2.5 concentrations at the Income Tax Office (ITO) receptor site over Delhi at 95% confidence level is highest in winter, ranging between 209 and 185 μg m⁻³ for the entire study period. The annual variability in air transport pathways is more in winter than in other seasons. Year-to-year variability is present in aerosol concentrations, especially during winter, with standard deviations varying from a

  1. Sources and potential application of waste heat utilization at a gas processing facility

    NASA Astrophysics Data System (ADS)

    Alshehhi, Alyas Ali

    Waste heat recovery (WHR) has the potential to significantly improve the efficiency of oil and gas plants, chemical and other processing facilities, and reduce their environmental impact. In this Thesis a comprehensive energy audit at Abu Dhabi Gas Industries Ltd. (GASCO) ASAB gas processing facilities is undertaken to identify sources of waste heat and evaluate their potential for on-site recovery. Two plants are considered, namely ASAB0 and ASAB1. Waste heat evaluation criteria include waste heat grade (i.e., temperature), rate, accessibility (i.e., proximity) to potential on-site waste heat recovery applications, and potential impact of recovery on installation performance and safety. The operating parameters of key waste heat source producing equipment are compiled, as well as characteristics of the waste heat streams. In addition, potential waste heat recovery applications and strategies are proposed, focusing on utilities, i.e., enhancement of process cooling/heating, electrical/mechanical power generation, and steam production. The sources of waste heat identified at ASAB facilities consist of gas turbine and gas generator exhaust gases, flared gases, excess propane cooling capacity, excess process steam, process gas air-cooler heat dissipation, furnace exhaust gases and steam turbine outlet steam. Of the above waste heat sources, exhaust gases from five gas turbines and one gas generator at ASAB0 plant, as well as from four gas turbines at ASAB1 plant, were found to meet the rate (i.e., > 1 MW), grade (i.e., > 180°C), accessibility (i.e., < 50 m from potential on-site WHR applications) and minimal impact criteria on the performance and safety of existing installations, for potential waste heat recovery. The total amount of waste heat meeting these criteria were estimated at 256 MW and 289 MW at ASAB0 and ASAB1 plants, respectively, both of which are substantial. Of the 289 MW waste generated at ASAB1, approximately 173 MW are recovered by waste heat

  2. The role of polar regions in global climate, and a new parameterization of global heat transport

    NASA Technical Reports Server (NTRS)

    Lindzen, R. S.; Farrell, B.

    1980-01-01

    The effects of the transport of heat between polar regions and other latitudes on climate sensitivity and stability are examined within the framework of simple energy balance models. New heat transport parameterizations adjust radiative equilibrium distributions of temperature with latitude on the basis of Hadley cells and baroclinically unstable eddies; including the effects of static stability changes with latitude eliminates the possible error in estimating the pole-equator temperature difference. It is found that climate sensitivity and stability for the new transport parameterizations can differ from other models, and is capable of simulating the sensitivity required by existing climate data.

  3. Air-Source Integrated Heat Pump for Near-Zero Energy Houses: Technology Status Report

    SciTech Connect

    Murphy, Richard W; Rice, C Keith; Baxter, Van D; Craddick, William G

    2007-07-01

    This report documents the development of an air-source integrated heat pump (AS-IHP) through the third quarter of FY2007. It describes the design, analyses and testing of the AS-IHP, and provides performance specifications for a field test prototype and proposed control strategy. The results obtained so far continue to support the AS-IHP being a promising candidate to meet the energy service needs for DOE's development of a Zero Energy Home (ZEH) by the year 2020.

  4. A fixed grid numerical methodology for phase change problems involving a moving heat source

    NASA Technical Reports Server (NTRS)

    Prakash, C.; Samonds, M.; Singhal, A. K.

    1987-01-01

    A numerical method for solving phase change problems involving a moving heat source is presented and illustrated by a two-dimensional example. The method uses a fixed grid and does not require the implementation of the Stefan condition at the solid-liquid interface; the procedure can thus be easily implemented using existing fixed grid codes. The problem considered as an example involves natural convection flow in the molten metal during tungsten inert gas welding.

  5. Diagnostics of the molecular component of photon-dominated regions with mechanical heating

    NASA Astrophysics Data System (ADS)

    Kazandjian, M. V.; Meijerink, R.; Pelupessy, I.; Israel, F. P.; Spaans, M.

    2012-06-01

    Context. Multitransition CO observations of galaxy centers have revealed that significant fractions of the dense circumnuclear gas have high kinetic temperatures, which are hard to explain by pure photon excitation, but may be caused by dissipation of turbulent energy. Aims: We aim to determine to what extent mechanical heating should be taken into account while modeling PDRs. To this end, the effect of dissipated turbulence on the thermal and chemical properties of PDRs is explored. Methods: Clouds are modeled as 1D semi-infinite slabs whose thermal and chemical equilibrium is solved for using the Leiden PDR-XDR code, where mechanical heating is added as a constant term throughout the cloud. An extensive parameter space in hydrogen gas density, FUV radiation field and mechanical heating rate is considered, covering almost all possible cases for the ISM relevant to the conditions that are encountered in galaxies. Effects of mechanical heating on the temperature profiles, column densities of CO and H2O and column density ratios of HNC, HCN and HCO+ are discussed. Results: In a steady-state treatment, mechanical heating seems to play an important role in determining the kinetic temperature of the gas in molecular clouds. Particularly in high-energy environments such as starburst galaxies and galaxy centers, model gas temperatures are underestimated by at least a factor of two if mechanical heating is ignored. The models also show that CO, HCN and H2O column densities increase as a function of mechanical heating. The HNC/HCN integrated column density ratio shows a decrease by a factor of at least two in high density regions with n ~ 105 cm-3, whereas that of HCN/HCO+ shows a strong dependence on mechanical heating for this same density range, with boosts of up to three orders of magnitude. Conclusions: The effects of mechanical heating cannot be ignored in studies of the molecular gas excitation whenever the ratio of the star formation rate to the gas density (SFR/n3

  6. Finite Volume Based Computer Program for Ground Source Heat Pump System

    SciTech Connect

    Menart, James A.

    2013-02-22

    This report is a compilation of the work that has been done on the grant DE-EE0002805 entitled ?Finite Volume Based Computer Program for Ground Source Heat Pump Systems.? The goal of this project was to develop a detailed computer simulation tool for GSHP (ground source heat pump) heating and cooling systems. Two such tools were developed as part of this DOE (Department of Energy) grant; the first is a two-dimensional computer program called GEO2D and the second is a three-dimensional computer program called GEO3D. Both of these simulation tools provide an extensive array of results to the user. A unique aspect of both these simulation tools is the complete temperature profile information calculated and presented. Complete temperature profiles throughout the ground, casing, tube wall, and fluid are provided as a function of time. The fluid temperatures from and to the heat pump, as a function of time, are also provided. In addition to temperature information, detailed heat rate information at several locations as a function of time is determined. Heat rates between the heat pump and the building indoor environment, between the working fluid and the heat pump, and between the working fluid and the ground are computed. The heat rates between the ground and the working fluid are calculated as a function time and position along the ground loop. The heating and cooling loads of the building being fitted with a GSHP are determined with the computer program developed by DOE called ENERGYPLUS. Lastly COP (coefficient of performance) results as a function of time are provided. Both the two-dimensional and three-dimensional computer programs developed as part of this work are based upon a detailed finite volume solution of the energy equation for the ground and ground loop. Real heat pump characteristics are entered into the program and used to model the heat pump performance. Thus these computer tools simulate the coupled performance of the ground loop and the heat pump

  7. Recovery Act: Finite Volume Based Computer Program for Ground Source Heat Pump Systems

    SciTech Connect

    James A Menart, Professor

    2013-02-22

    This report is a compilation of the work that has been done on the grant DE-EE0002805 entitled Finite Volume Based Computer Program for Ground Source Heat Pump Systems. The goal of this project was to develop a detailed computer simulation tool for GSHP (ground source heat pump) heating and cooling systems. Two such tools were developed as part of this DOE (Department of Energy) grant; the first is a two-dimensional computer program called GEO2D and the second is a three-dimensional computer program called GEO3D. Both of these simulation tools provide an extensive array of results to the user. A unique aspect of both these simulation tools is the complete temperature profile information calculated and presented. Complete temperature profiles throughout the ground, casing, tube wall, and fluid are provided as a function of time. The fluid temperatures from and to the heat pump, as a function of time, are also provided. In addition to temperature information, detailed heat rate information at several locations as a function of time is determined. Heat rates between the heat pump and the building indoor environment, between the working fluid and the heat pump, and between the working fluid and the ground are computed. The heat rates between the ground and the working fluid are calculated as a function time and position along the ground loop. The heating and cooling loads of the building being fitted with a GSHP are determined with the computer program developed by DOE called ENERGYPLUS. Lastly COP (coefficient of performance) results as a function of time are provided. Both the two-dimensional and three-dimensional computer programs developed as part of this work are based upon a detailed finite volume solution of the energy equation for the ground and ground loop. Real heat pump characteristics are entered into the program and used to model the heat pump performance. Thus these computer tools simulate the coupled performance of the ground loop and the heat pump. The

  8. Relation between Thermal and Magnetic Properties of Active Regions as a Probe of Coronal Heating Mechanisms

    NASA Astrophysics Data System (ADS)

    Yashiro, Seiji; Shibata, Kazunari

    2001-03-01

    We study the relation between thermal and magnetic properties of active regions in the corona observed with the soft X-ray telescope aboard Yohkoh. We derive the mean temperature and pressure of 64 mature active regions using the filter ratio technique, and examine the relationship of region size with temperature and pressure. We find that the temperature T of active regions increases with increasing region size L as T~L0.28, while the pressure P slightly decreases with the region size as P~L-0.16. We confirm the scaling law T~(PL)1/3 for mature active regions found by R. Rosner, W. H. Tucker, & G. S. Vaiana. We examined the magnetic properties of active regions by analyzing 31 active regions observed with the Solar and Heliospheric Observatory/Michelson Doppler Imager and find the following empirical scaling law between thermal and magnetic properties,Uth~Φ1.33,P~B0.78,where Uth, Φ, and B are the total thermal energy content, total magnetic flux, and average magnetic flux density of active regions, respectively. The former is consistent with the results of L. Golub et al., but the latter is not. Implications of our findings for coronal heating mechanisms are discussed.

  9. Design evolution and verification of the general-purpose heat source

    SciTech Connect

    Schock, A

    1980-01-01

    The General-Purpose Heat Source (GPHS) is a radioisotope heat source for use in space power systems. It employs a modular design, to make it adaptable to a wide range of energy conversion systems and power levels. Each 250 W module is completely autonomous, with its own passive safety provisions to prevent fuel release under all abort modes, including atmospheric reentry and earth impact. Prior development tests had demonstrated good impact survival as long as the iridium fuel capsules retained their ductility. This requires high impact temperatures, typically above 900/sup 0/C and reasonably fine grain size, which in turn requires avoidance of excessive operating temperatures and reentry temperatures. These three requirements - on operating, reentry, and impact temperatures - are in mutual conflict, since thermal design changes to improve any one of these temperatures tend to worsen one or both of the others. This conflict creates a difficult design problem, which for a time threatened the success of the program. The present paper describes how this problem was overcome by successive design revisions, supplemented by thermal analyses and confirmatory vibration and impact tests; and how this may be achieved while raising the specific power of the GPHS to 83 W/lb, a 50% improvement over previously flown radioisotope heat sources.

  10. Development and validation of a heated canister-based source sampling method

    SciTech Connect

    Crawford, R.J.; Elam, D.L.

    1994-12-31

    In response to the Clean Air Act Amendments of 1990, the US pulp and paper industry through the American Forest and Paper Association (AF and PA) has instituted a program to characterize hazardous air pollutant (HAP) emissions from a variety of sources at 16 facilities. To meet some of the specific needs of this program, a method has been developed, based on EPA Method 18, that uses a heated sampling system to transfer source gas samples to a heated stainless steel summa polished canister. After sampling, the canister is kept hot in an insulated box and transferred to an on-site mobile laboratory. All of the analyte system components are also heated so that the moisture is not allowed to condense in the sample before it is analyzed. An initial mill screening study, laboratory evaluation/ validation, and an EPA Method 301 validation on pulp mill sources have all been completed with acceptable results. This method is being used to quantitate 26 VOCs, e.g., methanol, acetone, methylene chloride, chloroform, benzene, methyl ethyl ketone, and methyl isobutyl ketone.

  11. Stress analysis and testing of the outer capsule design for the Strontium Heat Source Development Program

    SciTech Connect

    Simonen, F.A.; Shippell, R.J. Jr.; Atteridge, D.G.

    1980-01-01

    The objective of the Strontium Heat Source Development Program is to obtain the data needed to license /sup 90/SrF/sub 2/ heat sources - specifically the /sup 90/SrF/sub 2/ capsules produced in the Waste Encapsulation and Storage Facility (WESF) at Hanford. Toward this end, a high integrity outer capsule has been designed to replace the present outer capsule of the WESF /sup 90/SrF/sub 2/ capsule. The proposed design of a Hastelloy S outer capsule which features a mechanical interlock type of end closure is described. Qualification testing requirements are outlined, and stress analyses and developmental tests are described. These tests were performed on AISI-1018 steel stand-in capsules, and included both external pressure and impact tests. The external pressure tests showed that stress calculations seriously overestimated the pressure capability of the outer capsule. Possible reasons for the lack of agreement between the tests and the analyses are evaluated. The stress analyses and tests results indicate that the proposed outer capsule will meet the heat source qualification requirements. Future tests will be conducted to experimentally verify that the Hastelloy S outer capsule in an aged condition meets the structural integrity requirements.

  12. Development of a radioisotope heat source for the two-watt radioisotope thermoelectric generator

    NASA Astrophysics Data System (ADS)

    Howell, Edwin I.; McNeil, Dennis C.; Amos, Wayne R.

    1992-01-01

    Described is a radioisotope heat source for the Two-Watt Radioisotope Thermoelectric Generator (RTG) which is being considered for possible application by the U.S. Navy and for other Department of Defense applications. The heat source thermal energy (75 Wt) is produced from the alpha decay of plutonium-238 which is in the form of high-fired plutonium dioxide. The capsule is non-vented and consists of three domed cylindrical components each closed with a corresponding sealed end cap. Surrounding the fuel is the liner component, which is fabricated from a tantalum-based alloy, T-111. Also fabricated from T-111 is the next component, the strength member, which serves to meet pressure and impact criteria. The outermost component, or clad, is the oxidation- and corrosion-resistant nickel-based alloy, Hastelloy S. This paper defines the design considerations, details the hardware fabrication and welding processes, discusses the addition of yttrium to the fuel to reduce liner embrittlement, and describes the testing that has been conducted or is planned to assure that there is fuel containment not only during the heat source operational life, but also in case of an accident environment.

  13. Computational Analysis of the Thermal-Hydraulic Characteristics of the Encapsulated Nuclear Heat Source

    SciTech Connect

    Nishi, Yoshihisa; Ueda, Nobuyuki; Kinoshita, Izumi; Greenspan, Ehud

    2005-12-15

    The encapsulated nuclear heat source (ENHS) is a modular reactor that was selected by the 1999 U.S. Department of Energy Nuclear Energy Research Initiative program as a candidate Generation IV reactor concept. It is a fast neutron spectrum reactor cooled by lead-bismuth eutectic using natural circulation. One of the unique features of the ENHS is that the fission-generated heat is transferred from the primary coolant to the secondary coolant through rectangular intermediate heat exchanger (IHX) channels. The decay heat is removed by the reactor vessel auxiliary cooling system (RVACS).Events of protected loss of heat sink (PLOHS) and unprotected transient overpower (UTOP) have been analyzed for the ENHS using the CERES transient simulation code for liquid-metal-cooled reactors.It is found that the ENHS core is sufficiently cooled by the RVACS under the PLOHS condition. The core flow rate is affected by the growth and disappearance of temperature stratification in the primary plenum. It is also found that even under the inconceivable UTOP event considered, the ENHS reactor core is not catastrophically damaged. This is due to negative reactivity feedback from the radial expansion of the core, the grid plate, and the Doppler effect. The use of high-performance ferritic steel instead of HT-9 and proper design of the reactor control system could provide large safety margins against cladding damage.

  14. Model for the heat source of the Cerro Prieto magma-hydrothermal system, Baja California, Mexico

    SciTech Connect

    Elders, W.A.; Bird, D.K.; Williams, A.E.; Schiffman, P.; Cox, B.

    1981-01-01

    Earlier studies at Cerro Prieto led to the development of a qualitative model for fluid flow in the geothermal system before it was drilled and perturbed by production. Current efforts are directed towards numerical modeling of heat and mass transfer in the system in this undisturbed state. This one-dimensional model assumes that the heat source was a single basalt/gabbro intrusion which provided heat to the system as it cooled. After compilation of various information of the physical properties of the reservoir, the enthalpy contained in two 1 cm thick sections across the reservoir orthogonal to each other was calculated. Various shapes, sizes and depths for the intrusion were considered as initial conditions and boundary conditions for the calculations of heat transfer. A family of numerical models which so far gives the best matches to the conditions observed in the field today have in common a funnel-shaped intrusion with a top 4 km wide emplaced at a depth of 5 km some 30,000 to 50,000 years ago, providing heat to the geothermal system.

  15. Integration of Radioisotope Heat Source with Stirling Engine and Cooler for Venus Internal-Structure Mission

    SciTech Connect

    Schock, Alfred

    1993-10-01

    The primary mission goal is to perform long-term seismic measurements on Venus, to study its largely unknown internal structure. The principal problem is that most payload components cannot long survive Venus's harsh environment, 90 bars at 500 degrees C. To meet the mission life goal, such components must be protected by a refrigerated payload bay. JPL Investigators have proposed a mission concept employing a lander with a spherical payload bay cooled to 25 degrees C by a Stirling cooler powered by a radioisotope-heated Sitrling engine. To support JPL's mission study, NASA/Lewis and MTI have proposed a conceptual design for a hydraulically coupled Stirling engine and cooler, and Fairchild Space - with support of the Department of Energy - has proposed a design and integration scheme for a suitable radioisotope heat source. The key integration problem is to devise a simple, light-weight, and reliable scheme for forcing the radioisotope decay heat to flow through the Stirling engine during operation on Venus, but to reject that heat to the external environment when the Stirling engine and cooler are not operating (e.g., during the cruise phase, when the landers are surrounded by heat shields needed for protection during subsequent entry into the Venusian atmosphere.) A design and integration scheme for achieving these goals, together with results of detailed thermal analyses, are described in this paper. There are 7 copies in the file.

  16. Magnetic Characteristics of Active Region Heating Observed with TRACE, SOHO/EIT, and Yohkoh/SXT

    NASA Technical Reports Server (NTRS)

    Porter, J. G.; Falconer, D. A.; Moore, R. L.; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    Over the past several years, we have reported results from studies that have compared the magnetic structure and heating of the transition region and corona (both in active regions and in the quiet Sun) by combining X-ray and EUV images from Yohkoh and Solar and Heliospheric Observatory (SOHO) with photospheric magnetograms from ground-based observatories. Our findings have led us to the hypothesis that most heating throughout the corona is driven from near and below the base of the corona by eruptive microflares occurring in compact low-lying "core magnetic fields (i.e., fields rooted along and closely enveloping polarity inversion lines in the photospheric magnetic flux). We now extend these studies, comparing sequences of UV images from Transition Region and Coronal Explorer (TRACE) with longitudinal magnetograms from Kitt Peak and vector magnetograms from MUSIC. These comparisons confirm the previous results regarding the importance of core-field activity to active region heating. Activity in fields associated with satellite polarity inclusions and/or magnetically sheared configurations is especially prominent. This work is funded by NASA's Office of Space Science through the Sun-Earth Connection Guest Investigator Program and the Solar Physics Supporting Research and Technology Program.

  17. Dose distributions in regions containing beta sources: Irregularly shaped source distributions in homogeneous media

    SciTech Connect

    Werner, B.L. )

    1991-11-01

    Methods are introduced by which dose rate distributions due to nonuniform, irregularly shaped distributions of beta emitters can be calculated using dose rate distributions for uniform, spherical source distributions. The dose rate distributions can be written in the MIRD formalism.

  18. Effects of near-source heterogeneity on wave fields emanating from crustal sources observed at regional and teleseismic distances

    NASA Astrophysics Data System (ADS)

    Avants, Megan S.

    Near-source path effects imprint the wave field emanating from a seismic source and, if not well resolved, can obscure the details of source characteristics determined from observations of the seismic waves at regional and teleseismic distances (≥200 km). These effects are particularly strong for crustal sources such as shallow earthquakes and underground nuclear explosions. First, I explore 2D effects of random seismic P-wave velocity heterogeneity resulting from volumetric heterogeneity in the upper mantle and variability of the Moho on the amplitude decay of the regional phase Pn. Results indicate that the pattern of amplitude decay due to geometric spreading for a simple Earth model is more complex than that for an Earth model containing strong heterogeneity in the mantle lid. Next, I implement the representation theorem in a method which collects displacement and strain components output from a 3D finite difference program capable of including realistic surface topography and geologic structure in a 3D velocity model, and calculates teleseismic 3D Green functions (3DGFs) to specified receiver locations. Green functions produced from a 3D source model match Green functions produced from a 1D source model for theoretical source-receiver geometries. This new method is then applied to the problem of constraining the source depth and location of the three nuclear tests conducted by North Korea, by using a realistic topography model for the mountainous test region to calculate 3DGFs for several possible locations of each event. Amplitude ratios of P and pP from 3DGFs are correlated to those in observed stacked traces. Results show a sensitivity of this method to source depth and location across the test site region with source depths slightly greater than published estimates, but relative locations consistent with other studies. Finally, I determine a rupture model of the 2008 Wenchuan earthquake using 3DGFs calculated in a velocity model containing the dramatic

  19. Heating of the nighttime D region by very low frequency transmitters

    NASA Technical Reports Server (NTRS)

    Rodriguez, Juan V.; Inan, Umran S.; Bell, Timothy F.

    1994-01-01

    VLF signals propagating in the Earth-ionosphere waveguide are used to probe the heated nighttime D region over three U.S. Navy very low frequency (VLF,3-30 kHz) transmitters. Ionospheric cooling and heating are observed when a transmitter turns off and on in the course of normal operations. Heating by the 24.0-kHz NAA transmitter in Cutler, Maine, (1000 kW radiated power) was observed by this method in 41 of 52 off/on episodes during December 1992, increasing the amplitude and retarding the phase of the 21.4-kHz NSS probe wave propagating from Annapolis, Maryland, to Gander, Newfoundland, by as much as 0.84 dB and 5.3 deg, respectively. In 6 of these 41 episodes, the amplitude of the 28.5-kHz NAU probe wave propagating from Puerto Rico to Gander was also perturbed by as much as 0.29 dB. The latter observations were unexpected due to the greater than 770 km distance between NAA and the NAU-Gander great circle path. Heating by the NSS (21.4 kHz, 265 kW) and NLK (24.8 kHz, 850 kW) transmitters was observed serendipitously in data from earlier measurements of the amplitudes of VLF signals propagating in the Earth-ionosphere waveguide. A three-dimensional model of wave absorption and electron heating in a magnetized, weakly ionized plasma is used to calculate the extent nad shape of the collision frequency (i.e., electron temperature) enhancement above a VLF transmitter. The enhancements are annular, with a geomagnetic north-south asymmetry and a radius at the outer half-maximum of the collision frequency enhancement of about 150 km. Heating by the NAA transmitter is predicted to increase the nighttime D region electron temperature by as much as a factor of 3. The calculated changes in the D region conductivity are used in a three-dimensional model of propagation in the Earth-ionosphere wavelength to predict the effect of the heated patch on a subionospheric VLF probe wave. The range of predicted scattered field amplitudes is in general consistent with the observed

  20. Organosulfates in cloud water above the Ozarks' isoprene source region

    NASA Astrophysics Data System (ADS)

    Pratt, Kerri A.; Fiddler, Marc N.; Shepson, Paul B.; Carlton, Annmarie G.; Surratt, Jason D.

    2013-10-01

    Secondary organic aerosol formation via aqueous processing, particularly from the oxidation of biogenic volatile organic compounds, is hypothesized to contribute significantly to the global aerosol burden. In this study, electrospray ionization coupled with mass spectrometry (ESI-MS) was utilized to detect organosulfates and oligomers in cloud water collected in July above the Missouri Ozarks, an environment significantly influenced by isoprene oxidation. Community Multiscale Air Quality (CMAQ) modeling suggested that the aerosol at cloud height was characterized by high water, sulfate, and biogenic secondary organic aerosol content, conducive to aqueous-phase processing and organosulfate formation. CMAQ modeling also suggested the presence of gas-phase organic peroxides and nitrates, which can partition into the particle-phase and form organosulfates. Several potential organosulfates from isoprene, monoterpene, and sesquiterpene oxidation were detected in the cloud water. In particular, the ubiquitous organosulfate C5H12O7S (detected by ESI-MS at m/z -215), derived from isoprene epoxydiols, was detected. These results highlight the role of aqueous-phase reactions in biogenic SOA formation and cloud processes in isoprene oxidation-influenced regions.

  1. Advective heat transport associated with regional Earth degassing in central Apennine (Italy)

    NASA Astrophysics Data System (ADS)

    Chiodini, G.; Cardellini, C.; Caliro, S.; Chiarabba, C.; Frondini, F.

    2013-07-01

    In this work we show that the main springs of the central Apennine transport a total amount of heat of ˜2.2×109 J s-1. Most of this heat (57%) is the result of geothermal warming while the remaining 43% is due to gravitational potential energy dissipation. This result indicates that a large area of the central Apennines is very hot with heat flux values >300 mW m-2. These values are higher than those measured in the magmatic and famously geothermal provinces of Tuscany and Latium and about 1/3 of the total heat discharged at Yellowstone. This finding is surprising because the central Apennines have been thought to be a relatively cold area. Translated by CO2 rich fluids, this heat anomaly suggests the existence of a thermal source such as a large magmatic intrusion at depth. Recent tomographic images of the area support the presence of such an intrusion visible as a broad negative velocity anomaly in seismic waves. Our results indicate that the thermal regime of tectonically active areas of the Earth, where meteoric waters infiltrate and deeply circulate, should be revised on the basis of mass and energy balances of the groundwater systems.

  2. Source apportionment and health effect of NOx over the Pearl River Delta region in southern China.

    PubMed

    Lu, Xingcheng; Yao, Teng; Li, Ying; Fung, Jimmy C H; Lau, Alexis K H

    2016-05-01

    As one of the most notorious atmospheric pollutants, NOx not only promotes the formation of ozone but also has adverse health effects on humans. It is therefore of great importance to study the sources of NOx and its effects on human health. The Comprehensive Air Quality Model (CAMx) modeling system and ozone source apportionment technology (OSAT) were used to study the contribution of NOx from different emission sources over southern China. The results indicate that heavy duty diesel vehicles (HDDVs) and industrial point sources are the two major local NOx sources, accounting for 30.8% and 18.5% of local NOx sources, respectively. In Hong Kong, marine emissions contributed around 43.4% of local NOx in 2011. Regional transport is another important source of this pollutant, especially in February and November, and it can contribute over 30% of ambient NOx on average. Power plant point emission is an significant regional source in Zhuhai, Zhongshan and Foshan. The total emission sources are estimated to cause 2119 (0-4405) respiratory deaths and 991 (0-2281) lung cancer deaths due to long-term exposure to NOx in the Pearl River Delta region. Our results suggest that local governments should combine their efforts and vigorously promote further reduction of NOx emissions, especially for those sources that make a substantial contribution to NOx emissions and affect human health: HDDV, LDGV, industrial point sources and marine sources. PMID:26845361

  3. Augmentation of Stagnation Region Heat Transfer Due to Turbulence From a DLN Can Combustor

    NASA Technical Reports Server (NTRS)

    VanFossen, G. James; Bunker, Ronald S.

    2000-01-01

    Heat transfer measurements have been made in the stagnation region of a flat plate with a circular leading edge. Electrically heated aluminum strips placed symmetrically about the leading edge stagnation region were used to measure spanwise averaged heat transfer coefficients. The maximum Reynolds number obtained, based on leading edge diameter, was about 100,000. The model was immersed in the flow field downstream of an approximately half scale model of a can-type combustor from a low NO(x), ground based power-generating turbine. The tests were conducted with room temperature air; no fuel was added. Room air flowed into the combustor through six vane type fuel/air swirlers. The combustor can contained no dilution holes. The fuel/air swirlers all swirled the incoming airflow in a counter clockwise direction (facing downstream). A 5-hole probe flow field survey in the plane of the model stagnation point showed the flow was one big vortex with flow angles up to 36' at the outer edges of the rectangular test section. Hot wire measurements showed test section flow had very high levels of turbulence, around 28.5 percent, and had a relatively large axial-length scale-to-leading edge diameter ratio of 0.5. X-wire measurements showed the turbulence to be nearly isotropic. Stagnation heat transfer augmentation over laminar levels was around 77 percent and was about 14 percent higher than predicted by a previously developed correlation for isotropic grid generated turbulence.

  4. An Integrated Approach on Groundwater Flow and Heat/Solute Transport for Sustainable Groundwater Source Heat Pump (GWHP) System Operation

    NASA Astrophysics Data System (ADS)

    Park, D. K.; Bae, G. O.; Joun, W.; Park, B. H.; Park, J.; Park, I.; Lee, K. K.

    2015-12-01

    The GWHP system uses a stable temperature of groundwater for cooling and heating in buildings and thus has been known as one of the most energy-saving and cost-efficient renewable energy techniques. A GWHP facility was installed at an island located at the confluence of North Han and South Han rivers, Korea. Because of well-developed alluvium, the aquifer is suitable for application of this system, extracting and injecting a large amount of groundwater. However, the numerical experiments under various operational conditions showed that it could be vulnerable to thermal interference due to the highly permeable gravel layer, as a preferential path of thermal plume migration, and limited space for well installation. Thus, regional groundwater flow must be an important factor of consideration for the efficient operation under these conditions but was found to be not simple in this site. While the groundwater level in this site totally depends on the river stage control of Paldang dam, the direction and velocity of the regional groundwater flow, observed using the colloidal borescope, have been changed hour by hour with the combined flows of both the rivers. During the pumping and injection tests, the water discharges in Cheongpyeong dam affected their respective results. Moreover, the measured NO3-N concentrations might imply the effect of agricultural activities around the facility on the groundwater quality along the regional flow. It is obvious that the extraction and injection of groundwater during the facility operation will affect the fate of the agricultural contaminants. Particularly, the gravel layer must also be a main path for contaminant migration. The simulations for contaminant transport during the facility operation showed that the operation strategy for only thermal efficiency could be unsafe and unstable in respect of groundwater quality. All these results concluded that the integrated approach on groundwater flow and heat/solute transport is necessary

  5. VLF signatures of lightening-induced heating and ionization of the nighttime D-region

    SciTech Connect

    Inan, U.S.; Rodriquez, J.V. ); Idone, V.P. )

    1993-11-05

    48.5 kHz signals from a transmitter in Silver Creek, Nebraska, propagating to Huntsville (HU), Alabama over a [approximately]1200 km Great Circle Path (GCP) exhibit characteristic amplitude changes which appear within 20 ms of cloud-to-ground (CG) flashes located within 50 km of the path. Data are consistent with the heating of ionospheric electrons by the electromagnetic (EM) pulse from lightning producing ionization changes in the D-region over the thunderstorm.

  6. Flow Boiling Heat Transfer to Lithium Bromide Aqueous Solution in Subcooled Region

    NASA Astrophysics Data System (ADS)

    Furukawa, Masahiro; Kaji, Masao; Nishizumi, Takeharu; Ozaki, Shinji; Sekoguchi, Kotohiko

    To improve the thermal performance of high temperature generator of absorption chiller/heater, heat transfer characteristics of flow boiling of lithium bromide aqueous solution in the subcooled region were experimentally investigated. Experiments were made for water and lithium bromide aqueous solution flowing in a rectangular channel (5 mm × 20 mm cross section) with one side wall heated. Boiling onset quality of lithium bromide aqueous solution is greater than that of water. The heat transfer coefficient of lithium bromide aqueous solution is about a half of that of water under the same experimental conditions of inlet velocity and heat flux. The experimental data of heat transfer coefficient for water are compared with the empirical correlation of Thom et al.11) and a fairly good agreement is obtained. The predictive calculations by the method of Sekoguchi et al.12) are compared with the data for water and lithium bromide aqueous solution. Agreement between them is good for water, while the results for lithium bromide aqueous solution are not satisfactory.

  7. Simulation of tokamak SOL and divertor region including heat flux mitigation by gas puffing

    SciTech Connect

    Park, Jin Woo; Na, Y. S.; Hong, S. H.; Ahn, J.W.; Kim, D. K.; Han, Hyunsun; Shim, Seong Bo; Lee, Hae June

    2012-01-01

    Two-dimensional (2D), scrape-off layer (SOL)-divertor transport simulations are performed using the integrated plasma-neutral-impurity code KTRAN developed at Seoul National University. Firstly, the code is applied to reproduce a National Spherical Torus eXperiment (NSTX) discharge by using the prescribed transport coefficients and the boundary conditions obtained from the experiment. The plasma density, the heat flux on the divertor plate, and the D (alpha) emission rate profiles from the numerical simulation are found to follow experimental trends qualitatively. Secondly, predictive simulations are carried out for the baseline operation mode in Korea Superconducting Tokamak Advanced Research (KSTAR) to predict the heat flux on the divertor target plates. The stationary peak heat flux in the KSTAR baseline operation mode is expected to be 6.5 MW/m(2) in the case of an orthogonal divertor. To study the mitigation of the heat flux, we investigated the puffing effects of deuterium and argon gases. The puffing position is assumed to be in front of the strike point at the outer lower divertor plate. In the simulations, mitigation of the peak heat flux at the divertor target plates is found to occur when the gas puffing rate exceeds certain values, similar to 1.0 x 10(20) /s and similar to 5.0 x 10(18) /s for deuterium and argon, respectively. Multi-charged impurity transport is also investigated for both NSTX and KSTAR SOL and divertor regions.

  8. An analytic formulation for heating source memory in the thermospheric composition

    NASA Technical Reports Server (NTRS)

    Porter, H. S.; Mayr, H. G.; Hedin, A. E.

    1981-01-01

    Numerical calculations from a spectral circulation model are utilized to construct an analytic Green's function formulation describing the meridional, time-dependent thermospheric composition and temperature response during magnetic storms. The purpose is to develop a formulation that embodies source memory while being sufficiently simple to serve as a heuristic guide for empirical modeling. By passing from the discrete Fourier series representation, utilized for the numerical circulation model, to a continuous Fourier integral representation, explicit waves are obtained for the thermospheric response times. The response times are altitude and species dependent and can exceed two days below 200 km. Thus, for certain storm scenarios, pronounced source memory signatures for the composition and temperature are predicted. Response times obtained from the formulation are shown to give a response consistent with previously published neutral composition data from AE-C for the February 1974 storm when an ap dependent heat source is employed.

  9. A NEW ENTHALPY-BASED APPROACH TO THE TRANSITION REGION IN AN IMPULSIVELY HEATED CORONA

    SciTech Connect

    Bradshaw, S. J.; Cargill, P. J. E-mail: p.cargill@imperial.ac.uk

    2010-02-10

    Observations of the solar corona reveal persistent and ubiquitous redshifts, which correspond to bulk downflows. For an impulsively heated corona (e.g., by nanoflares), this indicates that a majority of the component loop structures are in the radiatively cooling phase of their lifecycle, and these motions should not be used to verify the predictions of any proposed theory of heating. However, the nature of the bulk downflows raises the possibility that enthalpy may play a key role in the energy balance of the loops and in particular that it powers the transition region radiation. In this Letter, we use one-dimensional hydrodynamic simulations of loop cooling to show that enthalpy losses from the corona are easily sufficient to power the transition region radiation. This contrasts with the long-held view that downward thermal conduction powers the transition region. The traditional distinction between the transition region and the corona in terms of temperature alone is then a grossly unphysical simplification, and a proper definition of the interface between these atmospheric layers requires a detailed knowledge of their energy balance. To this end, we propose a robust new definition of the transition region.

  10. Quantifying the impact of residential heating on the urban air quality in a typical European coal combustion region.

    PubMed

    Junninen, Heikki; Mønster, Jacob; Rey, Maria; Cancelinha, Jose; Douglas, Kevin; Duane, Matthew; Forcina, Victtorio; Müller, Anne; Lagler, Fritz; Marelli, Luisa; Borowiak, Annette; Niedzialek, Joanna; Paradiz, Bostian; Mira-Salama, Daniel; Jimenez, Jose; Hansen, Ute; Astorga, Covadonga; Stanczyk, Krzysztof; Viana, Mar; Querol, Xavier; Duvall, Rachelle M; Norris, Gary A; Tsakovski, Stefan; Wåhlin, Peter; Horák, Jiri; Larsen, Bo R

    2009-10-15

    The present investigation, carried out as a case study in a typical major city situated in a European coal combustion region (Krakow, Poland), aims at quantifying the impact on the urban air quality of residential heating by coal combustion in comparison with other potential pollution sources such as power plants, industry, and traffic. Emissions were measured for 20 major sources, including small stoves and boilers, and the particulate matter (PM) was analyzed for 52 individual compounds together with outdoor and indoor PM10 collected during typical winter pollution episodes. The data were analyzed using chemical mass balance modeling (CMB) and constrained positive matrix factorization (CMF) yielding source apportionments for PM10, B(a)P, and other regulated air pollutants namely Cd, Ni, As, and Pb. The results are potentially very useful for planning abatement strategies in all areas of the world, where coal combustion in small appliances is significant. During the studied pollution episodes in Krakow, European air quality limits were exceeded with up to a factor 8 for PM10 and up to a factor 200 for B(a)P. The levels of these air pollutants were accompanied by high concentrations of azaarenes, known markers for inefficient coal combustion. The major culprit for the extreme pollution levels was demonstrated to be residential heating by coal combustion in small stoves and boilers (>50% for PM10 and >90% B(a)P), whereas road transport (<10% for PM10 and <3% for B(a)P), and industry (4-15% for PM10 and <6% for B(a)P) played a lesser role. The indoor PM10 and B(a)P concentrations were at high levels similar to those of outdoor concentrations and were found to have the same sources as outdoors. The inorganic secondary aerosol component of PM10 amounted to around 30%, which for a large part may be attributed to the industrial emission of the precursors SO2 and NOx. PMID:19921921

  11. The feasibility of retrieving nuclear heat sources from orbit with the space shuttle

    SciTech Connect

    Pyatt, D.W.; Englehart, R.W.

    1980-01-01

    Spacecraft launched for orbital missions have a finite orbital lifetime. Current estimates for the lifetime of the nine nuclear powered U.S. satellites now in orbit range from 150 years to 10{sup 6} years. Orbital lifetime is determined primarily by altitude, solar activity, and the satellite ballistic coefficient. There is also the potential of collision with other satellites or space debris, which would reduce the lifetime in orbit. These orbiting power sources contain primarily Pu-238 and Pu-239 as the fuel material. Pu-238 has an approximate 87-year half life and so considerable amounts of daughter products are present after a few tens of years. In addition, there are minor but possibly significant amounts of impurity isotopes present with their own decay chains. Radioisotopic heat sources have been designed to evolving criteria since the first launches. Early models were designed to burn up upon reentry. Later designs were designed to reenter intact. After tens or hundreds of years in orbit, the ability of any orbiting heat source to reenter intact and impact while maintaining containment integrity is in doubt. Such ability could only be verified by design to provide protection in the case of early mission failures such as launch aborts, failure to achieve orbit, or the attainment of only a short orbit. With the development of the Space Shuttle there exists the potential ability to recover heat sources in orbit after their missions are completed. Such retrieval could allow the risk of eventual reentry burnup or impact with atmospheric dispersion and subsequent radiation doses to the public to be avoided.

  12. Nondestructive inspection of General Purpose Heat Source (GPHS) fueled clad girth welds

    SciTech Connect

    Reimus, M.A.; George, T.G.; Lynch, C.; Padilla, M.; Moniz, P.; Guerrero, A.; Moyer, M.W.; Placr, A.

    1998-01-01

    The General-Purpose Heat Source (GPHS) provides power for space missions by transmitting the heat of {sup 238}Pu decay to an array of thermoelectric elements. The GPHS is fabricated using an iridium-alloy to contain the {sup 238}PuO{sub 2} fuel pellet. GPHS capsules will be utilized in the upcoming Cassini mission to explore Saturn and its moons. The physical integrity of the girth weld is important to mission safety and performance. Because past experience had revealed a potential for initiation of small cracks in the girth weld overlap zone, a nondestructive inspection of each capsule weld is required. An ultrasonic method was used to inspect the welds of capsules fabricated for the Galileo mission. The instrument, transducer, and method used were state of the art at the time (early 1980s). The ultrasonic instrumentation and methods used to inspect the Cassini GPHSs was significantly upgraded from those used for the Galileo mission. GPHSs that had ultrasonic reflectors in excess of the reject specification level were subsequently inspected with radiography to provide additional engineering data used to accept/reject the heat source. This paper describes the Galileo-era ultrasonic instrumentation and methods and the subsequent upgrades made to support testing of Cassini GPHSs. Also discussed is the data obtained from radiographic examination and correlation to ultrasonic examination results. {copyright} {ital 1998 American Institute of Physics.}

  13. Nondestructive inspection of General Purpose Heat Source (GPHS) fueled clad girth welds

    SciTech Connect

    Reimus, M. A. H.; George, T. G.; Lynch, C.; Padilla, M.; Moniz, P.; Guerrero, A.; Moyer, M. W.; Placr, A.

    1998-01-15

    The General-Purpose Heat Source (GPHS) provides power for space missions by transmitting the heat of {sup 238}Pu decay to an array of thermoelectric elements. The GPHS is fabricated using an iridium-alloy to contain the {sup 238}PuO{sub 2} fuel pellet. GPHS capsules will be utilized in the upcoming Cassini mission to explore Saturn and its moons. The physical integrity of the girth weld is important to mission safety and performance. Because past experience had revealed a potential for initiation of small cracks in the girth weld overlap zone, a nondestructive inspection of each capsule weld is required. An ultrasonic method was used to inspect the welds of capsules fabricated for the Galileo mission. The instrument, transducer, and method used were state of the art at the time (early 1980s). The ultrasonic instrumentation and methods used to inspect the Cassini GPHSs was significantly upgraded from those used for the Galileo mission. GPHSs that had ultrasonic reflectors in excess of the reject specification level were subsequently inspected with radiography to provide additional engineering data used to accept/reject the heat source. This paper describes the Galileo-era ultrasonic instrumentation and methods and the subsequent upgrades made to support testing of Cassini GPHSs. Also discussed is the data obtained from radiographic examination and correlation to ultrasonic examination results.

  14. Optimal performance of heat engines with a finite source or sink and inequalities between means

    NASA Astrophysics Data System (ADS)

    Johal, Ramandeep S.

    2016-07-01

    Given a system with a finite heat capacity and a heat reservoir, and two values of initial temperatures, T+ and T-(source at T+ and the system is a sink at T-, or, when the reservoir is an infinite sink at T- and the system acts as a source at T+? It is found that in order to compare the total extracted work, and the corresponding efficiency in the two cases, we need to consider three regimes as suggested by an inequality, the so-called arithmetic mean-geometric mean inequality, involving the arithmetic and the geometric means of the two temperature values T+ and T-. In each of these regimes, the efficiency at total work obeys certain universal bounds, given only in terms of the ratio of initial temperatures. The general theoretical results are exemplified for thermodynamic systems for which internal energy and temperature are power laws of the entropy. The conclusions may serve as benchmarks in the design of heat engines, where we can choose the nature of the finite system, so as to tune the total extractable work and/or the corresponding efficiency.

  15. Parametric design study of ``mini-generator`` with 6-watt heat source

    SciTech Connect

    Schock, A.; Or, C.T.

    1995-01-20

    The Fairchild study showed that generator designs based on a single 1-watt RHU had very poor thermal efficiencies. At their optimum operating point, more than half of the generated heat was lost through the thermal insulation. This resulted in system efficiency of only 2.2%, compared to 7.2% for current Radioisotope Thermoelectric Generators (RTGs). Moreover, there were serious doubts about the fabricability of the required multicouples, particularly of the series/parallel connections between the large number (900) of thermoelectric legs of very small cross-section (0.21 mm square). All in all, the preceding paper showed that neither JPL`s Power Stick design nor the Fairchild-generated derivatives based on the 1-watt heat source looked promising. The present paper describes a similar parametric study of a mini-generator based on a 6-watt heat source, and compares its performance and fabricability to that of the optimum Power Stick derivative and of the current RTG design for the same mission. {copyright} 1995 {ital American} {ital Institute} {ital of} {ital Physics}

  16. Parametric design study of ``mini-generator'' with 6-watt heat source

    NASA Astrophysics Data System (ADS)

    Schock, Alfred; Or, Chuen T.

    1995-01-01

    The Fairchild study showed that generator designs based on a single 1-watt RHU had very poor thermal efficiencies. At their optimum operating point, more than half of the generated heat was lost through the thermal insulation. This resulted in system efficiency of only 2.2%, compared to 7.2% for current Radioisotope Thermoelectric Generators (RTGs). Moreover, there were serious doubts about the fabricability of the required multicouples, particularly of the series/parallel connections between the large number (900) of thermoelectric legs of very small cross-section (0.21 mm square). All in all, the preceding paper showed that neither JPL's Power Stick design nor the Fairchild-generated derivatives based on the 1-watt heat source looked promising. The present paper describes a similar parametric study of a mini-generator based on a 6-watt heat source, and compares its performance and fabricability to that of the optimum Power Stick derivative and of the current RTG design for the same mission.

  17. Optimal performance of heat engines with a finite source or sink and inequalities between means.

    PubMed

    Johal, Ramandeep S

    2016-07-01

    Given a system with a finite heat capacity and a heat reservoir, and two values of initial temperatures, T_{+} and T_{-}(source at T_{+} and the system is a sink at T_{-}, or, when the reservoir is an infinite sink at T_{-} and the system acts as a source at T_{+}? It is found that in order to compare the total extracted work, and the corresponding efficiency in the two cases, we need to consider three regimes as suggested by an inequality, the so-called arithmetic mean-geometric mean inequality, involving the arithmetic and the geometric means of the two temperature values T_{+} and T_{-}. In each of these regimes, the efficiency at total work obeys certain universal bounds, given only in terms of the ratio of initial temperatures. The general theoretical results are exemplified for thermodynamic systems for which internal energy and temperature are power laws of the entropy. The conclusions may serve as benchmarks in the design of heat engines, where we can choose the nature of the finite system, so as to tune the total extractable work and/or the corresponding efficiency. PMID:27575093

  18. Turbulent diffusion from a heated line source in non-equilibrium grid turbulence

    NASA Astrophysics Data System (ADS)

    Nedic, Jovan; Tavoularis, Stavros

    2015-11-01

    We have investigated turbulent diffusion of heat injected passively from a line source in equilibrium and non-equilibrium grid-generated turbulence, which are, respectively, flows in which the value of the non-dimensional rate of kinetic energy dissipation is constant or changes with streamwise distance from the grid. We used three grids with uniform square meshes and one fractal square grid (FSG), all of the same solidity, to generate non-equilibrium and equilibrium turbulence in a wind-tunnel. The regular grids have mesh sizes that are comparable to the first (RG160), second (RG80) and fourth (RG18) iterations of the fractal grid. The heated line source was inserted on the centre-plane of the grids at either of two downstream locations or an upstream one and it spanned the entire width of the wind-tunnel. We found that RG160 produced the greatest heat diffusion, followed by FSG, RG80 and RG18, in this order. The apparent turbulent diffusivity produced by the four grids also decreased in the same order. These findings conform with Taylor's theory of diffusion by continuous movements. Moreover, the present study demonstrates that the fractal space-scale unfolding (SSU) mechanism does not apply to grids with the same solidity but different effective mesh sizes. Supported by NSERC.

  19. General-Purpose Heat Source development: safety test program. Postimpact evaluation, Design Iteration Test 2

    SciTech Connect

    Schonfeld, F.W.; George, T.G.

    1984-06-01

    The General-Purpose Heat Source (GPHS) provides power for space missions by transmitting the heat of /sup 238/PuO/sub 2/ decay to thermoelectric elements. Because of the inevitable return of certain missions, the heat source must be Designed and constructed to survive both re-entry and Earth impact. The Design Iteration Test (DIT) series is part of an ongoing test program. In the first Design Iteration Test (DIT-1), a full GPHS module ontaining four iridium-alloy capsules loaded with /sup 238/PuO/sub 2/ was impacted at 57 m/s and 930/sup 0/C. All four capsules survived and none was breached. The capsules used in DIT-1 were loaded and welded at Los Alamos. The second Design Iteration Test (DIT-2) also used a full GPHS module and was impacted at 58 m/s and 930/sup 0/C. The four iridium-alloy capsules used in this test were loaded and welded at the Savannah River Plant (SRP). Postimpact examination revealed that two capsules had survived and two capsules had breached; a small quantity (approx. = 50 ..mu..g) of /sup 238/PuO/sub 2/ was released from the breached capsules. Internal cracking similar to that observed in the DIT-1 capsules was evident in all four of the DIT-2 capsules. Postimpact analyses of the units are described with emphasis on weld structure and performance.

  20. Case study for ARRA-funded ground-source heat pump (GSHP) demonstration at Oakland University

    SciTech Connect

    Im, Piljae; Liu, Xiaobing

    2015-09-01

    High initial costs and lack of public awareness of ground-source heat pump (GSHP) technology are the two major barriers preventing rapid deployment of this energy-saving technology in the United States. Under the American Recovery and Reinvestment Act (ARRA), 26 GSHP projects have been competitively selected and carried out to demonstrate the benefits of GSHP systems and innovative technologies for cost reduction and/or performance improvement. This paper highlights the findings of a case study of one of the ARRA-funded GSHP demonstration projects, a ground-source variable refrigerant flow (GS-VRF) system installed at the Human Health Building at Oakland University in Rochester, Michigan. This case study is based on the analysis of measured performance data, maintenance records, construction costs, and simulations of the energy consumption of conventional central heating, ventilation, and air-conditioning (HVAC) systems providing the same level of space conditioning as the demonstrated GS-VRF system. The evaluated performance metrics include the energy efficiency of the heat pump equipment and the overall GS-VRF system, pumping performance, energy savings, carbon emission reductions, and cost-effectiveness of the GS-VRF system compared with conventional HVAC systems. This case study also identified opportunities for reducing uncertainties in the performance evaluation, improving the operational efficiency, and reducing the installed cost of similar GSHP systems in the future.

  1. Air Pollution in Moscow Region and Kiev during Heat Wave in July-August 2010

    NASA Astrophysics Data System (ADS)

    Zvyagintsev, A. M.; Tarasova, O. A.; Belikov, I. B.; Blum, O. B.; Elansky, N. F.; Kuznetsova, I. N.; Shumsky, R. A.

    2010-12-01

    The summer of 2010 was extremely hot and dry over the European part of Russia and Ukraine. Some days the air temperature rose up to 40 degrees Celsius. An anomaly of the mesoscale atmospheric processes in the form of a blocking anticyclone in the low atmosphere caused untypical transport of air masses: south-eastern winds became dominating in the Moscow region in summer 2010 instead of north-western transport, which is usually prevailing in summer. Due to long drought and high temperatures (ca. 1 month from July 15) natural fires occurred from time to time over huge territories to the east of Moscow (from Nyzhny Novgorod to Riazan). Forest and peat fires led to unprecedented air pollution and transport of biomass burning products over long distances. The smoke plume repeatedly extended to the Moscow megapolis. Arrival of the polluted air from the burning sources nearest to Moscow was accompanied by a haze with reduced visibility down to 100-200 m, as well as by a strong smell of burning and corresponding abrupt decrease of air quality. Strong photochemical smog of the Los-Angeles type was observed some days in the Moscow megapolis. Air masses polluted with the products of natural fires traveled within the territory of central Russia without crossing its western border. They had no impact on the air quality in Kiev, where air composition was defined by local emissions and meteorological conditions. The short intervals with temperatures above 35 degrees Celsius were accompanied by change of air masses and precipitation events. This paper presents measurement of surface ozone, NOx and CO mixing ratios and PM10 in the Moscow region as well as ozone and NOx level observations in Kiev. Eight-hourly averaged surface ozone mixing ratios in Moscow exceeded 60 ppb during about 30 days. During 20 days a haze was observed in the city from time to time, and the haze was continuous for the period from 3rd to 10th of August. The most intensive smog was observed during 6-8 August

  2. Contribution Assessment of Regional Air Pollution over Northeast Asia using CMAQ Source Apportionment Tools

    NASA Astrophysics Data System (ADS)

    Choi, K.; Woo, J.; Kim, H.; Lee, J.; Kim, C.

    2011-12-01

    East Asia is one of the largest emission source regions in the world because of the large population and fast economic growth for several decades. Recent observation from space also demonstrates that emissions in East Asia - especially China - have been increased impressively since 1995. A number of regional scale transport studies using comprehensive 3D modeling system such as CMAQ have been conducted to understand transboundary air pollution. The contribution assessment using such a comprehensive modeling system, however, was not extensively investigated in this region. Air pollution contributions from multiple source types and regions over East Asia were examined using CMAQ based source apportionment tool off-line coupled with a meteorological model (WRF). The simulation was conducted for the entire year of 2009. The CMAQ ozone & particle precursor tagging methodologies (OPTM) source apportionment tool were applied in our study. An anthropogenic emissions inventory and processing methodology have been developed in support of the source-receptor modeling study in East Asia region. Emissions from open biomass burning and biogenic source were also estimated to support air quality contributions assessment from various sources and source types. Remote sensing-based atmosphere information and ground based monitoring data has been included to evaluate the simulation results. The results of our analysis will be presented at the conference.

  3. Transient natural ventilation of a room with a distributed heat source

    NASA Astrophysics Data System (ADS)

    Fitzgerald, Shaun D.; Woods, Andrew W.

    We report on an experimental and theoretical study of the transient flows which develop as a naturally ventilated room adjusts from one temperature to another. We focus on a room heated from below by a uniform heat source, with both high- and low-level ventilation openings. Depending on the initial temperature of the room relative to (i) the final equilibrium temperature and (ii) the exterior temperature, three different modes of ventilation may develop. First, if the room temperature lies between the exterior and the equilibrium temperature, the interior remains well-mixed and gradually heats up to the equilibrium temperature. Secondly, if the room is initially warmer than the equilibrium temperature, then a thermal stratification develops in which the upper layer of originally hot air is displaced upwards by a lower layer of relatively cool inflowing air. At the interface, some mixing occurs owing to the effects of penetrative convection. Thirdly, if the room is initially cooler than the exterior, then on opening the vents, the original air is displaced downwards and a layer of ambient air deepens from above. As this lower layer drains, it is eventually heated to the ambient temperature, and is then able to mix into the overlying layer of external air, and the room becomes well-mixed. For each case, we present new laboratory experiments and compare these with some new quantitative models of the transient flows. We conclude by considering the implications of our work for natural ventilation of large auditoria.

  4. Strategic GHG reduction through the use of ground source heat pump technology

    NASA Astrophysics Data System (ADS)

    Hanova, J.; Dowlatabadi, H.

    2007-10-01

    Higher energy prices and concern about climate change is drawing increasing attention to ground source heat pump (GSHP) systems. Their clear advantage lies in being able to provide heating using 25 to 30% of the energy consumed by even the most efficient conventional alternatives. Their drawback has been high capital costs and uncertainty about whether the emissions associated with the electric power used to energise the system has higher system-wide emissions than the highest-efficiency furnaces. This study delineates circumstances under which GSHP systems achieve net emission reductions, for different electricity generation methods, heat pump efficiencies, and heating loads. We illustrate the effect of relative fuel prices on annual operating savings using fuel prices in multiple countries. Annual operating savings determine how rapidly the technology achieves payback and then generates return on the initial capital investment. Finally, we highlight the least cost supply curve for using GSHP to reduce greenhouse gas emissions. Using the United States as a base reference case, this study explores the potential of GSHP in cold-climate countries worldwide.

  5. A Study of the Structure of the Source Region of the Solar Wind in Support of a Solar Probe Mission

    NASA Technical Reports Server (NTRS)

    Habbal , Shadia R.

    1998-01-01

    Despite the richness of the information about the physical properties and the structure of the solar wind provided by the Ulysses and SOHO observations, fundamental questions regarding the nature of the coronal heating mechanisms, their source, and the manifestations of the fast and slow solar wind, still remain unanswered. The last unexplored frontier to establish the connection between the structure and dynamics of the solar atmosphere, its extension into interplanetary space, and the mechanisms responsible for the evolution of the solar wind, is the corona between 1 and 30 R(sub s). A Solar Probe mission offers an unprecedented opportunity to explore this frontier. The uniqueness of this mission stems from its trajectory in a plane perpendicular to the ecliptic which reaches within 9 R(sub s), of the solar surface over the poles and 3 - 9 R(sub s), at the equator. With a complement of simultaneous in situ and remote sensing observations, this mission is destined to have a significant impact on our understanding of the fundamental processes that heat the corona and drive the solar wind. The Solar Probe should be able to detect remnants and signatures of the processes which heat the corona and accelerate the solar wind. The primary objective of this proposal was to explore the structure of the different source regions of the solar wind through complementary observational and theoretical studies in support of a Solar Probe mission.

  6. Analysis of classical Fourier, SPL and DPL heat transfer model in biological tissues in presence of metabolic and external heat source

    NASA Astrophysics Data System (ADS)

    Kumar, Dinesh; Singh, Surjan; Rai, K. N.

    2016-06-01

    In this paper, the temperature distribution in a finite biological tissue in presence of metabolic and external heat source when the surface subjected to different type of boundary conditions is studied. Classical Fourier, single-phase-lag (SPL) and dual-phase-lag (DPL) models were developed for bio-heat transfer in biological tissues. The analytical solution obtained for all the three models using Laplace transform technique and results are compared. The effect of the variability of different parameters such as relaxation time, metabolic heat source, spatial heat source, different type boundary conditions on temperature distribution in different type of the tissues like muscle, tumor, fat, dermis and subcutaneous based on three models are analyzed and discussed in detail. The result obtained in three models is compared with experimental observation of Stolwijk and Hardy (Pflug Arch 291:129-162, 1966). It has been observe that the DPL bio-heat transfer model provides better result in comparison of other two models. The value of metabolic and spatial heat source in boundary condition of first, second and third kind for different type of thermal therapies are evaluated.

  7. Thermal convection in a rotating fluid sphere with self gravity, uniform heat source and precession

    NASA Astrophysics Data System (ADS)

    Avila, Ruben

    2014-11-01

    The natural convection of a rotating fluid sphere with a self gravity field (which is proportional to the radius of the sphere) and with precessional motion is presented. The spherical bounding surface is maintained at a constant and uniform temperature which is lower than the temperature of the fluid. A constant and uniform heat source increases the temperature of the fluid confined in the sphere. The fluid sphere rotates and precesses with angular velocity vectors that form a certain inclination angle between them. The governing non-steady, three dimensional Navier-Stokes equations for an incompressible fluid, formulated in a Cartesian coordinate system (in the mantle reference frame) are solved by using the spectral element method. The influence of the Rayleigh number, the Ekman number and the Poincare number on the flow patterns, the temperature field and the heat transfer rate from the fluid sphere is presented. DGAPA-PAPIIT Project: IN117314-3.

  8. Atmosphere-entry behavior of a modular, disk-shaped, isotope heat source.

    NASA Technical Reports Server (NTRS)

    Vorreiter, J. W.; Pitts, W. C.; Stine, H. A.; Burns, J. J.

    1973-01-01

    The authors have studied the entry and impact behavior of an isotope heat source for space nuclear power that disassembles into a number of modules which would enter the earth's atmosphere separately if a flight aborted. These modules are disk-shaped units, each with its own reentry heat shield and protective impact container. In normal operation, the disk modules are stacked inside the generator, but during a reentry abort they separate and fly as individual units of low ballistic coefficient. Flight tests at hypersonic speeds have confirmed that a stack of disks will separate and assume a flat-forward mode of flight. Free-fall tests of single disks have demonstrated a nominal impact velocity of 30 m/sec at sea level for a practical range of ballistic coefficients.

  9. Study of heat sources interacting in integrated circuits by laser mirage effect

    NASA Astrophysics Data System (ADS)

    Perpiñà, X.; Jordà, X.; Vellvehi, M.; Altet, J.

    2014-08-01

    This work exploits the mirage effect to analyze multiple heat sources thermally interacting in an integrated circuit (IC) by means of a probe IR laser beam, which strikes on the die lateral walls and passes through the die substrate. Under such conditions, the criteria for locating such hot spots, as well as their relative power dissipation, are discussed on the basis of a theoretical model inferred in this work. Finally, the technique feasibility is shown in a real application scenario, obtaining 5-μm spatial lateral resolution and an error in power dissipation measurements below 5%. This method may become a practical alternative to usual off-chip techniques for inspecting hot spots in ICs and to experimentally characterize heat flow in the semiconductor substrate.

  10. Combined heat and power (cogeneration) plant based on renewable energy sources and electrochemical hydrogen systems

    NASA Astrophysics Data System (ADS)

    Grigor'ev, S. A.; Grigor'ev, A. S.; Kuleshov, N. V.; Fateev, V. N.; Kuleshov, V. N.

    2015-02-01

    The layout of a combined heat and power (cogeneration) plant based on renewable energy sources (RESs) and hydrogen electrochemical systems for the accumulation of energy via the direct and inverse conversion of the electrical energy from RESs into the chemical energy of hydrogen with the storage of the latter is described. Some efficient technical solutions on the use of electrochemical hydrogen systems in power engineering for the storage of energy with a cyclic energy conversion efficiency of more than 40% are proposed. It is shown that the storage of energy in the form of hydrogen is environmentally safe and considerably surpasses traditional accumulator batteries by its capacitance characteristics, being especially topical in the prolonged absence of energy supply from RESs, e.g., under the conditions of polar night and breathless weather. To provide the required heat consumption of an object during the peak period, it is proposed to burn some hydrogen in a boiler house.

  11. Atmospheric entry heating - A criterion to distinguish between asteroidal and cometary sources of interplanetary dust

    NASA Technical Reports Server (NTRS)

    Flynn, G. J.

    1989-01-01

    Interplanetary dust samples obtained in the earth stratosphere by NASA sampling aircraft have been analyzed to ascertain the duration of their exposure as small particles in space, and the peak temperature they attained during atmospheric entry and deceleration. A three-dimensional orbital evolution model is then developed from these data which involves asteroidal and cometary sources for the dust as well as the influence of Poynting-Robertson drag. Particles from comets with perihelia greater than 1.2 AU typically undergo 600-800 C heating, while those from comets with smaller perihelia are heated to temperatures in excess of 800 C. Atmospheric-entry velocities inferred are consistent with the major fraction of stratospheric cosmic dust being derived from parent bodies in the main asteroid belt.

  12. Study of heat sources interacting in integrated circuits by laser mirage effect

    SciTech Connect

    Perpiñà, X.; Jordà, X.; Vellvehi, M.; Altet, J.

    2014-08-25

    This work exploits the mirage effect to analyze multiple heat sources thermally interacting in an integrated circuit (IC) by means of a probe IR laser beam, which strikes on the die lateral walls and passes through the die substrate. Under such conditions, the criteria for locating such hot spots, as well as their relative power dissipation, are discussed on the basis of a theoretical model inferred in this work. Finally, the technique feasibility is shown in a real application scenario, obtaining 5-μm spatial lateral resolution and an error in power dissipation measurements below 5%. This method may become a practical alternative to usual off-chip techniques for inspecting hot spots in ICs and to experimentally characterize heat flow in the semiconductor substrate.

  13. Improved heating efficiency with High-Intensity Focused Ultrasound using a new ultrasound source excitation.

    PubMed

    Bigelow, Timothy A

    2009-01-01

    High-Intensity Focused Ultrasound (HIFU) is quickly becoming one of the best methods to thermally ablate tissue noninvasively. Unlike RF or Laser ablation, the tissue can be destroyed without inserting any probes into the body minimizing the risk of secondary complications such as infections. In this study, the heating efficiency of HIFU sources is improved by altering the excitation of the ultrasound source to take advantage of nonlinear propagation. For ultrasound, the phase velocity of the ultrasound wave depends on the amplitude of the wave resulting in the generation of higher harmonics. These higher harmonics are more efficiently converted into heat in the body due to the frequency dependence of the ultrasound absorption in tissue. In our study, the generation of the higher harmonics by nonlinear propagation is enhanced by transmitting an ultrasound wave with both the fundamental and a higher harmonic component included. Computer simulations demonstrated up to a 300% increase in temperature increase compared to transmitting at only the fundamental for the same acoustic power transmitted by the source. PMID:19963801

  14. An experimental study of waveguide coupled microwave heating with conventional multicusp negative ion sources

    SciTech Connect

    Komppula, J.; Kalvas, T.; Koivisto, H.; Laulainen, J.; Tarvainen, O.

    2015-04-08

    Negative ion production with conventional multicusp plasma chambers utilizing 2.45 GHz microwave heating is demonstrated. The experimental results were obtained with the multicusp plasma chambers and extraction systems of the RF-driven RADIS ion source and the filament driven arc discharge ion source LIISA. A waveguide microwave coupling system, which is almost similar to the one used with the SILHI ion source, was used. The results demonstrate that at least one third of negative ion beam obtained with inductive RF-coupling (RADIS) or arc discharge (LIISA) can be achieved with 1 kW of 2.45 GHz microwave power in CW mode without any modification of the plasma chamber. The co-extracted electron to H{sup −} ratio and the optimum pressure range were observed to be similar for both heating methods. The behaviour of the plasma implies that the energy transfer from the microwaves to the plasma electrons is mainly an off-resonance process.

  15. Micro- and Nanoscale Energetic Materials as Effective Heat Energy Sources for Enhanced Gas Generators.

    PubMed

    Kim, Sang Beom; Kim, Kyung Ju; Cho, Myung Hoon; Kim, Ji Hoon; Kim, Kyung Tae; Kim, Soo Hyung

    2016-04-13

    In this study, we systematically investigated the effect of micro- and nanoscale energetic materials in formulations of aluminum microparticles (Al MPs; heat source)/aluminum nanoparticles (Al NPs; heat source)/copper oxide nanoparticles (CuO NPs; oxidizer) on the combustion and gas-generating properties of sodium azide microparticles (NaN3 MPs; gas-generating agent) for potential applications in gas generators. The burn rate of the NaN3 MP/CuO NP composite powder was only ∼0.3 m/s. However, the addition of Al MPs and Al NPs to the NaN3 MP/CuO NP matrix caused the rates to reach ∼1.5 and ∼5.3 m/s, respectively. In addition, the N2 gas volume flow rate generated by the ignition of the NaN3 MP/CuO NP composite powder was only ∼0.6 L/s, which was significantly increased to ∼1.4 and ∼3.9 L/s by adding Al MPs and Al NPs, respectively, to the NaN3 MP/CuO NP composite powder. This suggested that the highly reactive Al MPs and NPs, with the assistance of CuO NPs, were effective heat-generating sources enabling the complete thermal decomposition of NaN3 MPs upon ignition. Al NPs were more effective than Al MPs in the gas generators because of the increased reactivity induced by the reduced particle size. Finally, we successfully demonstrated that a homemade airbag with a specific volume of ∼140 mL could be rapidly and fully inflated by the thermal activation of nanoscale energetic material-added gas-generating agents (i.e., NaN3 MP/Al NP/CuO NP composites) within the standard time of ∼50 ms for airbag inflation. PMID:27007287

  16. A Study of Regional Wave Source Time Functions of Central Asian Earthquakes

    NASA Astrophysics Data System (ADS)

    Xie, J.; Perry, M. R.; Schult, F. R.; Wood, J.

    2014-12-01

    Despite the extensive use of seismic regional waves in seismic event identification and attenuation tomography, very little is known on how seismic sources radiate energy into these waves. For example, whether regional Lg wave has the same source spectrum as that of the local S has been questioned by Harr et al. and Frenkel et al. three decades ago; many current investigators assume source spectra in Lg, Sn, Pg, Pn and Lg coda waves have either the same or very similar corner frequencies, in contrast to local P and S spectra whose corner frequencies differ. The most complete information on how the finite source ruptures radiate energy into regional waves is contained in the time domain source time functions (STFs). To estimate the STFs of regional waves using the empirical Green's function (EGF) method, we have been substantially modifying a semi-automotive computer procedure to cope with the increasingly diverse and inconsistent naming patterns of new data files from the IRIS DMC. We are applying the modified procedure to many earthquakes in central Asia to study the STFs of various regional waves to see whether they have the same durations and pulse shapes, and how frequently source directivity occur. When applicable, we also examine the differences between STFs of local P and S waves and those of regional waves. The result of these analyses will be presented at the meeting.

  17. USING A DIFFERENTIAL EMISSION MEASURE AND DENSITY MEASUREMENTS IN AN ACTIVE REGION CORE TO TEST A STEADY HEATING MODEL

    SciTech Connect

    Winebarger, Amy R.; Schmelz, Joan T.; Warren, Harry P.; Saar, Steve H.; Kashyap, Vinay L.

    2011-10-10

    The frequency of heating events in the corona is an important constraint on the coronal heating mechanisms. Observations indicate that the intensities and velocities measured in active region cores are effectively steady, suggesting that heating events occur rapidly enough to keep high-temperature active region loops close to equilibrium. In this paper, we couple observations of active region (AR) 10955 made with the X-Ray Telescope and the EUV Imaging Spectrometer on board Hinode to test a simple steady heating model. First we calculate the differential emission measure (DEM) of the apex region of the loops in the active region core. We find the DEM to be broad and peaked around 3 MK. We then determine the densities in the corresponding footpoint regions. Using potential field extrapolations to approximate the loop lengths and the density-sensitive line ratios to infer the magnitude of the heating, we build a steady heating model for the active region core and find that we can match the general properties of the observed DEM for the temperature range of 6.3 < log T < 6.7. This model, for the first time, accounts for the base pressure, loop length, and distribution of apex temperatures of the core loops. We find that the density-sensitive spectral line intensities and the bulk of the hot emission in the active region core are consistent with steady heating. We also find, however, that the steady heating model cannot address the emission observed at lower temperatures. This emission may be due to foreground or background structures, or may indicate that the heating in the core is more complicated. Different heating scenarios must be tested to determine if they have the same level of agreement.

  18. Source Sector and Region Contributions to BC and PM2.5 in Central Asia

    EPA Science Inventory

    Particulate matter (PM) mass concentrations, seasonal cycles, source sector and source region contributions in Central Asia (CA) are analyzed for the period April 2008-July 2009 using the STEM chemical transport model and modeled meteorology from the WRF model. Predicted AOD valu...

  19. Seismic discrimination of the 2009 North Korean nuclear explosion based on regional source spectra

    NASA Astrophysics Data System (ADS)

    Hong, Tae-Kyung

    2013-04-01

    Seismic discrimination of an underground nuclear explosion (UNE) based on regional waveforms in continental margins is challenging due to large variations among waveforms. The 2009 North Korean UNE test was conducted in the far eastern Eurasian plate. The UNE was recorded by densely-located regional seismic stations, and regional waveforms exhibit highly path-dependent amplitude and arrival time features due to complex crustal structures. Regional source spectra are calculated by correcting for the path effects on the waveforms. A two-step approach is proposed for stable inversion of source-spectral parameters and path parameters. Characteristic overshoot features are observed in the source spectra, particularly strong in Pn. The path parameter, Q, is determined uniquely regardless of the source-spectral model implemented, which suggests stable separation of path effects from waveform records. The estimated source spectra fit well to a theoretical UNE source-spectral model. The fitness between the estimated and theoretical source-spectral models allows us to discriminate UNEs from natural earthquakes. Also, the P/S source-spectral ratio is observed to be an effective discriminant of UNE.

  20. REGIONAL AIR POLLUTION STUDY: POINT AND AREA SOURCE ORGANIC EMISSION INVENTORY

    EPA Science Inventory

    An inventory of organic emissions from stationary and mobile sources has been assembled for the St. Louis Air Quality Control Region. The inventory covers point and area sources for process, combustion and evaporative emissions. A breakdown into five categories has been assigned ...