Calculation tool for transported geothermal energy using two-step absorption process

DOE Data Explorer

Kyle Gluesenkamp

2016-02-01

This spreadsheet allows the user to calculate parameters relevant to techno-economic performance of a two-step absorption process to transport low temperature geothermal heat some distance (1-20 miles) for use in building air conditioning. The parameters included are (1) energy density of aqueous LiBr and LiCl solutions, (2) transportation cost of trucking solution, and (3) equipment cost for the required chillers and cooling towers in the two-step absorption approach. More information is available in the included public report: "A Technical and Economic Analysis of an Innovative Two-Step Absorption System for Utilizing Low-Temperature Geothermal Resources to Condition Commercial Buildings"

The machined surface of magnesium AZ31 after rotary turning at air cooling condition

NASA Astrophysics Data System (ADS)

Akhyar, G.; Purnomo, B.; Hamni, A.; Harun, S.; Burhanuddin, Y.

2018-04-01

Magnesium is a lightweight metal that is widely used as an alternative to iron and steel. Magnesium has been applied in the automotive industry to reduce the weight of a component, but the machining process has the disadvantage that magnesium is highly flammable because it has a low flash point. High temperature can cause the cutting tool wear and contributes to the quality of the surface roughness. The purpose of this study is to obtain the value of surface roughness and implement methods of rotary cutting tool and air cooling output vortex tube cooler to minimize the surface roughness values. Machining parameters that is turning using rotary cutting tool at speed the workpiece of (Vw) 50, 120, 160 m/min, cutting speed of rotary tool of (Vt) 25, 50, 75 m/min, feed rate of (f) 0.1, 0.15, 0.2 mm/rev, and depth of cut of 0.3 mm. Type of tool used is a carbide tool diameter of 16 mm and air cooling pressure of 6 bar. The results show the average value of the lowest surface roughness on the speed the workpiece of 80 m/min, cutting speed of rotary tool of 50 m/min, feed rate of 0.2 mm/rev, and depth of cut of 0.3 mm. While the average value of the highest surface roughness on the speed the workpiece of 160 m/min, cutting speed of rotary tool of 50 m/min, feed rate of 0.2 mm/rev, and depth of cut of 0.3 mm. The influence of machining parameters concluded the higher the speed of the workpiece the surface roughness value higher. Otherwise the higher cutting speed of rotary tool then the lower the surface roughness value. The observation on the surface of the rotary tool, it was found that no uniform tool wear which causes non-uniform surface roughness. The use of rotary cutting tool contributing to lower surface roughness values generated.

Feasibility of Actively Cooled Silicon Nitride Airfoil for Turbine Applications Demonstrated

NASA Technical Reports Server (NTRS)

Bhatt, Ramakrishna T.

2001-01-01

Nickel-base superalloys currently limit gas turbine engine performance. Active cooling has extended the temperature range of service of nickel-base superalloys in current gas turbine engines, but the margin for further improvement appears modest. Therefore, significant advancements in materials technology are needed to raise turbine inlet temperatures above 2400 F to increase engine specific thrust and operating efficiency. Because of their low density and high-temperature strength and thermal conductivity, in situ toughened silicon nitride ceramics have received a great deal of attention for cooled structures. However, the high processing costs and low impact resistance of silicon nitride ceramics have proven to be major obstacles for widespread applications. Advanced rapid prototyping technology in combination with conventional gel casting and sintering can reduce high processing costs and may offer an affordable manufacturing approach. Researchers at the NASA Glenn Research Center, in cooperation with a local university and an aerospace company, are developing actively cooled and functionally graded ceramic structures. The objective of this program is to develop cost-effective manufacturing technology and experimental and analytical capabilities for environmentally stable, aerodynamically efficient, foreign-object-damage-resistant, in situ toughened silicon nitride turbine nozzle vanes, and to test these vanes under simulated engine conditions. Starting with computer aided design (CAD) files of an airfoil and a flat plate with internal cooling passages, the permanent and removable mold components for gel casting ceramic slips were made by stereolithography and Sanders machines, respectively. The gel-cast part was dried and sintered to final shape. Several in situ toughened silicon nitride generic airfoils with internal cooling passages have been fabricated. The uncoated and thermal barrier coated airfoils and flat plates were burner rig tested for 30 min without and with air cooling. Without cooling, the surface temperature of the flat plate reached approximately 2350 F. Starting with computer aided design (CAD) files of an airfoil and a flat plate with internal cooling passages, the permanent and removable mold components for gel casting ceramic slips were made by stereolithography and Sanders machines, respectively. The gel-cast part was dried and sintered to final shape. Several in situ toughened silicon nitride generic airfoils with internal cooling passages have been fabricated. The uncoated and thermal barrier coated airfoils and flat plates were burner rig tested for 30 min without and with air cooling. Without cooling, the surface temperature of the flat plate reached approximately 2350 F. With cooling, the surface temperature decreased to approximately 1910 F--a drop of approximately 440 F. This preliminary study demonstrates that a near-net-shape silicon nitride airfoil can be fabricated and that silicon nitride can sustain severe thermal shock and the thermal gradients induced by cooling and, thus, is a viable candidate for cooled components.

Development of a Pressure Box to Evaluate Reusable-Launch-Vehicle Cryogenic-Tank Panels

NASA Technical Reports Server (NTRS)

Ambur, Damodar R.; Sikora, Joseph; Maguire, James F.; Winn, Peter M.

1996-01-01

A cryogenic pressure-box test machine has been designed and is being developed to test full-scale reusable-launch-vehicle cryogenic-tank panels. This machine is equipped with an internal pressurization system, a cryogenic cooling system, and a heating system to simulate the mechanical and thermal loading conditions that are representative of a reusable-launch-vehicle mission profile. The cryogenic cooling system uses liquid helium and liquid nitrogen to simulate liquid hydrogen and liquid oxygen tank internal temperatures. A quartz lamp heating system is used for heating the external surface of the test panels to simulate cryogenic-tank external surface temperatures during re-entry of the launch vehicle. The pressurization system uses gaseous helium and is designed to be controlled independently of the cooling system. The tensile loads in the axial direction of the test panel are simulated by means of hydraulic actuators and a load control system. The hoop loads in the test panel are reacted by load-calibrated turnbuckles attached to the skin and frame elements of the test panel. The load distribution in the skin and frames can be adjusted to correspond to the tank structure by using these turnbuckles. The seal between the test panel and the cryogenic pressure box is made from a reinforced Teflon material which can withstand pressures greater than 52 psig at cryogenic temperatures. Analytical results and tests on prototype test components indicate that most of the cryogenic-tank loading conditions that occur in flight can be simulated in the cryogenic pressure-box test machine.

Theoretical model for Sub-Doppler Cooling with EIT System

NASA Astrophysics Data System (ADS)

He, Peiru; Tengdin, Phoebe; Anderson, Dana; Rey, Ana Maria; Holland, Murray

2016-05-01

We propose a of sub-Doppler cooling mechanism that takes advantage of the unique spectral features and extreme dispersion generated by the so-called Electromagnetically Induced Transparency (EIT) effect, a destructive quantum interference phenomenon experienced by atoms with Lambda-shaped energy levels when illuminated by two light fields with appropriate frequencies. By detuning the probe lasers slightly from the ``dark resonance'', we observe that atoms can be significantly cooled down by the strong viscous force within the transparency window, while being just slightly heated by the diffusion caused by the small absorption near resonance. In contrast to polarization gradient cooling or EIT sideband cooling, no external magnetic field or external confining potential are required. Using a semi-classical method, analytical expressions, and numerical simulations, we demonstrate that the proposed EIT cooling method can lead to temperatures well below the Doppler limit. This work is supported by NSF and NIST.

Method and apparatus for semi-solid material processing

DOEpatents

Han, Qingyou [Knoxville, TN; Jian, Xiaogang [Knoxville, TN; Xu, Hanbing [Knoxville, TN; Meek, Thomas T [Knoxville, TN

2009-02-24

A method of forming a material includes the steps of: vibrating a molten material at an ultrasonic frequency while cooling the material to a semi-solid state to form non-dendritic grains therein; forming the semi-solid material into a desired shape; and cooling the material to a solid state. The method makes semi-solid castings directly from molten materials (usually a metal), produces grain size usually in the range of smaller than 50 .mu.m, and can be easily retrofitted into existing conventional forming machine.

Method and apparatus for semi-solid material processing

DOEpatents

Han, Qingyou [Knoxville, TN; Jian, Xiaogang [Knoxville, TN; Xu, Hanbing [Knoxville, TN; Meek, Thomas T [Knoxville, TN

2007-05-15

A method of forming a material includes the steps of: vibrating a molten material at an ultrasonic frequency while cooling the material to a semi-solid state to form non-dendritic grains therein; forming the semi-solid material into a desired shape; and cooling the material to a solid state. The method makes semi-solid castings directly from molten materials (usually a metal), produces grain size usually in the range of smaller than 50 .mu.m, and can be easily retrofitted into existing conventional forming machine.

Developing Test Apparatus and Measurements of AC Loss of High Temperature Superconductors

DTIC Science & Technology

2012-11-01

temperature of the coil is not raised significantly. The second system, a larger machine, designed with a long term prospective to serve a test bed for...four sample chambers inside the vacuum gap, LN2 – cooled sample holder (currently only one is in use), the laminated back iron, and the outer shell...machine. accommodate a variety of different small coils and linear tapes. This assembly is surrounded by the laminated back iron and the outer shell

Radiative Cooling: Principles, Progress, and Potentials

PubMed Central

Hossain, Md. Muntasir

2016-01-01

The recent progress on radiative cooling reveals its potential for applications in highly efficient passive cooling. This approach utilizes the maximized emission of infrared thermal radiation through the atmospheric window for releasing heat and minimized absorption of incoming atmospheric radiation. These simultaneous processes can lead to a device temperature substantially below the ambient temperature. Although the application of radiative cooling for nighttime cooling was demonstrated a few decades ago, significant cooling under direct sunlight has been achieved only recently, indicating its potential as a practical passive cooler during the day. In this article, the basic principles of radiative cooling and its performance characteristics for nonradiative contributions, solar radiation, and atmospheric conditions are discussed. The recent advancements over the traditional approaches and their material and structural characteristics are outlined. The key characteristics of the thermal radiators and solar reflectors of the current state‐of‐the‐art radiative coolers are evaluated and their benchmarks are remarked for the peak cooling ability. The scopes for further improvements on radiative cooling efficiency for optimized device characteristics are also theoretically estimated. PMID:27812478

Power generating system and method utilizing hydropyrolysis

DOEpatents

Tolman, R.

1986-12-30

A vapor transmission cycle is described which burns a slurry of coal and water with some of the air from the gas turbine compressor, cools and cleans the resulting low-Btu fuel gas, burns the clean fuel gas with the remaining air from the compressor, and extracts the available energy in the gas turbine. The cycle lends itself to combined-cycle cogeneration for the production of steam, absorption cooling, and electric power.

Metal concentration and X-ray cool spectral component in the central region of the Centaurus cluster of galaxies

NASA Technical Reports Server (NTRS)

Fukazawa, Yasushi; Ohashi, Takaya; Fabian, Andrew C.; Canizares, Claude R.; Ikebe, Yasushi; Makishima, Kazuo; Mushotzky, Richard F.; Yamashita, Koujun

1994-01-01

Spatially resolved energy spectra in the energy range 0.5-10 keV have been measured for the Centaurus cluster of galaxies with Advanced Satellite for Cosmology and Astrophysics (ASCA). Within 10 min (200 kpc) from the cluster center, the helium-like iron K emission line exhibits a dramatic increase toward the center rising from an equivalent width approximately 500 eV to approximately 1500 eV corresponding to an abundance change from 0.3 to 1.0 solar. The presence of strong iron L lines indicates an additional cool component (kT approximately 1 keV) within 10 min from the center. The cool component requires absorption in excess of the galactic value and this excess absorption increases towards the central region of the cluster. In the surrounding region with radius greater than 10 min, the spectra are well described by a single temperature thermal model with kT approximately 4 keV and spatially uniform abundances at about 0.3-0.4 times solar. The detection of metal-rich hot and cool gas in the cluster center implies a complex nature of the central cluster gas which is likely to be related to the presence of the central cD galaxy NGC 4696.

Copernicus observations of Betelgeuse and Antares

NASA Technical Reports Server (NTRS)

Bernat, A. P.; Lambert, D. L.

1975-01-01

Copernicus observations of the M-supergiants, alpha Ori and alpha Sco, are presented. The MgII h and k resonance lines are strongly in emission in both stars. The k line is highly asymmetric in both stars but the h line is symmetric. Upper limits for several other resonance lines are given for alpha Ori. The possibility is explored that the k line asymmetry is caused by overlying resonance lines of MnI and FeI formed in the cool circumstellar gas shells around these stars. Observations of the MnI 4030-4033 A lines are used to show that circumstellar shell absorption is too weak to explain the asymmetry. It is suggested that the absorption occurs in a cool turbulent region between the base of the circumstellar shell and the top of the chromosphere.

Active cooling of pulse compression diffraction gratings for high energy, high average power ultrafast lasers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alessi, David A.; Rosso, Paul A.; Nguyen, Hoang T.

Laser energy absorption and subsequent heat removal from diffraction gratings in chirped pulse compressors poses a significant challenge in high repetition rate, high peak power laser development. In order to understand the average power limitations, we have modeled the time-resolved thermo-mechanical properties of current and advanced diffraction gratings. We have also developed and demonstrated a technique of actively cooling Petawatt scale, gold compressor gratings to operate at 600W of average power - a 15x increase over the highest average power petawatt laser currently in operation. As a result, combining this technique with low absorption multilayer dielectric gratings developed in ourmore » group would enable pulse compressors for petawatt peak power lasers operating at average powers well above 40kW.« less

Active cooling of pulse compression diffraction gratings for high energy, high average power ultrafast lasers

DOE PAGES

Alessi, David A.; Rosso, Paul A.; Nguyen, Hoang T.; ...

2016-12-26

Laser energy absorption and subsequent heat removal from diffraction gratings in chirped pulse compressors poses a significant challenge in high repetition rate, high peak power laser development. In order to understand the average power limitations, we have modeled the time-resolved thermo-mechanical properties of current and advanced diffraction gratings. We have also developed and demonstrated a technique of actively cooling Petawatt scale, gold compressor gratings to operate at 600W of average power - a 15x increase over the highest average power petawatt laser currently in operation. As a result, combining this technique with low absorption multilayer dielectric gratings developed in ourmore » group would enable pulse compressors for petawatt peak power lasers operating at average powers well above 40kW.« less

Massive Warm/Hot Galaxy Coronae as Probed by UV/X-Ray Oxygen Absorption and Emission. I. Basic Model

NASA Astrophysics Data System (ADS)

Faerman, Yakov; Sternberg, Amiel; McKee, Christopher F.

2017-01-01

We construct an analytic phenomenological model for extended warm/hot gaseous coronae of L* galaxies. We consider UV O VI Cosmic Origins Spectrograph (COS)-Halos absorption line data in combination with Milky Way (MW) X-ray O vii and O viii absorption and emission. We fit these data with a single model representing the COS-Halos galaxies and a Galactic corona. Our model is multi-phased, with hot and warm gas components, each with a (turbulent) log-normal distribution of temperatures and densities. The hot gas, traced by the X-ray absorption and emission, is in hydrostatic equilibrium in an MW gravitational potential. The median temperature of the hot gas is 1.5× {10}6 K and the mean hydrogen density is ˜ 5× {10}-5 {{cm}}-3. The warm component as traced by the O VI, is gas that has cooled out of the high density tail of the hot component. The total warm/hot gas mass is high and is 1.2× {10}11 {M}⊙ . The gas metallicity we require to reproduce the oxygen ion column densities is 0.5 solar. The warm O VI component has a short cooling time (˜ 2× {10}8 years), as hinted by observations. The hot component, however, is ˜ 80 % of the total gas mass and is relatively long-lived, with {t}{cool}˜ 7× {10}9 years. Our model supports suggestions that hot galactic coronae can contain significant amounts of gas. These reservoirs may enable galaxies to continue forming stars steadily for long periods of time and account for “missing baryons” in galaxies in the local universe.

Solar heating, cooling and domestic hot water system installed at Columbia Gas System Service Corporation, Columbus, Ohio

NASA Technical Reports Server (NTRS)

1980-01-01

The solar energy system installed in the building has 2,978 sq ft of single axis tracking, concentrating collectors and provides solar energy for space heating, space cooling and domestic hot water. A 1,200,000 Btu/hour water tube gas boiler provides hot water for space heating. Space cooling is provided by a 100 ton hot water fired absorption chiller. Domestic hot water heating is provided by a 50 gallon natural gas domestic storage water heater. Extracts from the site files, specification references, drawings, installation, operation and maintenance instructions are included.

Integration of a molten carbonate fuel cell with a direct exhaust absorption chiller

NASA Astrophysics Data System (ADS)

Margalef, Pere; Samuelsen, Scott

A high market value exists for an integrated high-temperature fuel cell-absorption chiller product throughout the world. While high-temperature, molten carbonate fuel cells are being commercially deployed with combined heat and power (CHP) and absorption chillers are being commercially deployed with heat engines, the energy efficiency and environmental attributes of an integrated high-temperature fuel cell-absorption chiller product are singularly attractive for the emerging distributed generation (DG) combined cooling, heating, and power (CCHP) market. This study addresses the potential of cooling production by recovering and porting the thermal energy from the exhaust gas of a high-temperature fuel cell (HTFC) to a thermally activated absorption chiller. To assess the practical opportunity of serving an early DG-CCHP market, a commercially available direct fired double-effect absorption chiller is selected that closely matches the exhaust flow and temperature of a commercially available HTFC. Both components are individually modeled, and the models are then coupled to evaluate the potential of a DG-CCHP system. Simulation results show that a commercial molten carbonate fuel cell generating 300 kW of electricity can be effectively coupled with a commercial 40 refrigeration ton (RT) absorption chiller. While the match between the two "off the shelf" units is close and the simulation results are encouraging, the match is not ideal. In particular, the fuel cell exhaust gas temperature is higher than the inlet temperature specified for the chiller and the exhaust flow rate is not sufficient to achieve the potential heat recovery within the chiller heat exchanger. To address these challenges, the study evaluates two strategies: (1) blending the fuel cell exhaust gas with ambient air, and (2) mixing the fuel cell exhaust gases with a fraction of the chiller exhaust gas. Both cases are shown to be viable and result in a temperature drop and flow rate increase of the gases before the chiller inlet. The results show that no risk of cold end corrosion within the chiller heat exchanger exists. In addition, crystallization is not an issue during system operation. Accounting for the electricity and the cooling produced and disregarding the remaining thermal energy, the second strategy is preferred and yields an overall estimated efficiency of 71.7%.

Air-Conditioning for Electric Vehicles

NASA Technical Reports Server (NTRS)

Popinski, Z.

1984-01-01

Combination of ammonia-absorption refrigerator, roof-mounted solar collectors, and 200 degrees C service electric-vehicle motor provides evaporative space-heating/space cooling system for electric-powered and hybrid fuel/electric vehicles.

Ideology of a multiparametric system for estimating the insulation system of electric machines on the basis of absorption testing methods

NASA Astrophysics Data System (ADS)

Kislyakov, M. A.; Chernov, V. A.; Maksimkin, V. L.; Bozhin, Yu. M.

2017-12-01

The article deals with modern methods of monitoring the state and predicting the life of electric machines. In 50% of the cases of failure in the performance of electric machines is associated with insulation damage. As promising, nondestructive methods of control, methods based on the investigation of the processes of polarization occurring in insulating materials are proposed. To improve the accuracy of determining the state of insulation, a multiparametric approach is considered, which is a basis for the development of an expert system for estimating the state of health.

Cooling Duct Analysis for Transpiration/Film Cooled Liquid Propellant Rocket Engines

NASA Technical Reports Server (NTRS)

Micklow, Gerald J.

1996-01-01

The development of a low cost space transportation system requires that the propulsion system be reusable, have long life, with good performance and use low cost propellants. Improved performance can be achieved by operating the engine at higher pressure and temperature levels than previous designs. Increasing the chamber pressure and temperature, however, will increase wall heating rates. This necessitates the need for active cooling methods such as film cooling or transpiration cooling. But active cooling can reduce the net thrust of the engine and add considerably to the design complexity. Recently, a metal drawing process has been patented where it is possible to fabricate plates with very small holes with high uniformity with a closely specified porosity. Such a metal plate could be used for an inexpensive transpiration/film cooled liner to meet the demands of advanced reusable rocket engines, if coolant mass flow rates could be controlled to satisfy wall cooling requirements and performance. The present study investigates the possibility of controlling the coolant mass flow rate through the porous material by simple non-active fluid dynamic means. The coolant will be supplied to the porous material by series of constant geometry slots machined on the exterior of the engine.

Green buildings: Implications for acousticians

NASA Astrophysics Data System (ADS)

Noble, Michael R.

2005-04-01

This presentation will deal with the practical implications of green design protocols of the US Green Building Council on interior acoustics of buildings. Three areas of particular consequence to acousticians will be discussed. Ventilation Systems: reduced energy consumption goals dictate reliance on natural cooling and ventilation using ambient air when possible. The consequent large openings in the building envelope to bring fresh air into rooms, and similar sized openings to transfer the mixed air out, can severely compromise the noise isolation of the rooms concerned. Radiant Cooling: the heavy concrete floors of buildings can be used as a thermal flywheel to lessen the cooling load, which forces the concrete ceilings to be exposed to the occupied rooms for heat transfer, and strictly limits the application of acoustical absorption on the ceilings. This challenges the room acoustics design. Green Materials: the LEED protocols require the elimination of potentially harmful finishes, including fibrous materials which may impact air quality or contribute to health problems. Since the backbone of sound absorption is glass and mineral fibres, this further challenges provision of superior room acoustics. Examples and commentary will be provided based on current and recent projects.

Non-LTE models of Titan's upper atmosphere

NASA Technical Reports Server (NTRS)

Yelle, Roger V.

1991-01-01

Models for the thermal structure of Titan's upper atmosphere, between 0.1 mbar and 0.01 nbar are presented. The calculations include non-LTE heating/cooling in the rotation-vibration bands of CH4, C2H2, and C2H6, absorption of solar IR radiation in the near-IR bands of CH4 and subsequent cascading to the nu-4 band of CH4, absorption of solar EUV and UV radiation, thermal conduction and cooling by HCN rotational lines. Unlike earlier models, the calculated exospheric temperature agrees well with observations, because of the importance of HCN cooling. The calculations predict a well-developed mesopause with a temperature of 135-140 K at an altitude of approximately 600 km and pressure of about 0.1 microbar. The mesopause is at a higher pressure than predicted by earlier calculations because non-LTE radiative transfer in the rotation-vibration bands of CH4, C2H2, and C2H6 is treated in an accurate manner. The accuracy of the LTE approximation for source functions and heating rates is discussed.

Solar Energy system performance evaluation: El Toro, California, March 1981-November 1981

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pakkala, P.A.

The El Toro Library is a public library facility in California with an active solar energy system designed to supply 97% of the heating load and 60% of the cooling load. The system is equipped with 1427 square feet of evacuated tube collectors, a 1500-gallon steel storage tank, and an auxiliary natural-gas-fired heating unit. During the period from March 1981 through November 1981 the system supplied only 16% of the space cooling load, far short of the 60% design value. Problems are reported related to control of a valve and of collection, low absorption chiller coefficient of performance during partmore » of the period, and small collector area. Performance data are reported for the system, including solar savings ratio, conventional fuel savings, system performance factor, system coefficient of performance, solar energy utilization, and system operation. Subsystem performance data are also given for the collector, storage, and space cooling subsystems and absorption chiller. The system is briefly described along with performance evaluation techniques and sensors, and typical data are presented for one month. Some weather data are also included. (LEW)« less

Ultra-Compact Transputer-Based Controller for High-Level, Multi-Axis Coordination

NASA Technical Reports Server (NTRS)

Zenowich, Brian; Crowell, Adam; Townsend, William T.

2013-01-01

The design of machines that rely on arrays of servomotors such as robotic arms, orbital platforms, and combinations of both, imposes a heavy computational burden to coordinate their actions to perform coherent tasks. For example, the robotic equivalent of a person tracing a straight line in space requires enormously complex kinematics calculations, and complexity increases with the number of servo nodes. A new high-level architecture for coordinated servo-machine control enables a practical, distributed transputer alternative to conventional central processor electronics. The solution is inherently scalable, dramatically reduces bulkiness and number of conductor runs throughout the machine, requires only a fraction of the power, and is designed for cooling in a vacuum.

Smart Cutting Tools and Smart Machining: Development Approaches, and Their Implementation and Application Perspectives

NASA Astrophysics Data System (ADS)

Cheng, Kai; Niu, Zhi-Chao; Wang, Robin C.; Rakowski, Richard; Bateman, Richard

2017-09-01

Smart machining has tremendous potential and is becoming one of new generation high value precision manufacturing technologies in line with the advance of Industry 4.0 concepts. This paper presents some innovative design concepts and, in particular, the development of four types of smart cutting tools, including a force-based smart cutting tool, a temperature-based internally-cooled cutting tool, a fast tool servo (FTS) and smart collets for ultraprecision and micro manufacturing purposes. Implementation and application perspectives of these smart cutting tools are explored and discussed particularly for smart machining against a number of industrial application requirements. They are contamination-free machining, machining of tool-wear-prone Si-based infra-red devices and medical applications, high speed micro milling and micro drilling, etc. Furthermore, implementation techniques are presented focusing on: (a) plug-and-produce design principle and the associated smart control algorithms, (b) piezoelectric film and surface acoustic wave transducers to measure cutting forces in process, (c) critical cutting temperature control in real-time machining, (d) in-process calibration through machining trials, (e) FE-based design and analysis of smart cutting tools, and (f) application exemplars on adaptive smart machining.

Realization of an all-solid-state cryocooler using optical refrigeration

NASA Astrophysics Data System (ADS)

Meng, Junwei; Albrecht, Alexander R.; Gragossian, Aram; Lee, Eric; Volpi, Azzurra; Ghasemkhani, Mohammadreza; Hehlen, Markus P.; Epstein, Richard I.; Sheik-Bahae, Mansoor

2018-05-01

Optical refrigeration of rare-earth-doped solids has reached the boiling point of argon, 87 K, and is expected to cool to that of nitrogen, 77 K, in the near future. This technology is poised to pave the way to compact, reliable, and vibrationfree all-solid-state optical cryocoolers. By attaching the Yb:YLF cooling crystal to a cold finger via a double 90° kink thermal link, we have cooled a silicon temperature sensor to below 151 K. An advanced design of the thermal link and the clamshell surrounding the cooled assembly successfully controlled the flow of heat and radiation to allow cooling of a payload to cryogenic temperatures. Key elements of the design were a low-absorption thermal link material, an optimized thermal link geometry, and a spectrally-selective coating of the clamshell.

The formation process of the He I lambda 10830 line in cool giant stars

NASA Technical Reports Server (NTRS)

Luttermoser, Donald G.

1993-01-01

The Final Report on the formation process of the He I lambda 10830 line in cool giant stars is presented. The research involves observing a sample of cool giant stars with ROSAT. These stars were selected from the list of bright stars which display He I lambda 10830 in absorption or emission and lie on the cool side of the coronal dividing line. With measured x ray fluxes or upper limits measured by the Position Sensitive Proportional Counter (PSPC), the role x rays play in the formation of this important line was investigated using the non-LTE radiative transfer code PANDORA. Hydrodynamic calculations were performed to investigate the contributions of acoustic wave heating in the formation of this line as well.

Performance and heat transfer characteristics of the laser-heated rocket - A future space transportation system

NASA Technical Reports Server (NTRS)

Shoji, J. M.; Larson, V. R.

1976-01-01

The application of advanced liquid-bipropellant rocket engine analysis techniques has been utilized for prediction of the potential delivered performance and the design of thruster wall cooling schemes for laser-heated rocket thrusters. Delivered specific impulse values greater than 1000 lbf-sec/lbm are potentially achievable based on calculations for thrusters designed for 10-kW and 5000-kW laser beam power levels. A thruster wall-cooling technique utilizing a combination of regenerative cooling and a carbon-seeded hydrogen boundary layer is presented. The flowing carbon-seeded hydrogen boundary layer provides radiation absorption of the heat radiated from the high-temperature plasma. Also described is a forced convection thruster wall cooling design for an experimental test thruster.

A Method for Eliminating Beam Steering Error for the Modulated Absorption-Emission Thermometry Technique

DTIC Science & Technology

2015-01-01

emissivity and the radiative intensity of the gas over a spectral band. The temperature is then calculated from the Planck function. The technique does not...pressure budget for cooling channels reduces pump horsepower and turbine inlet temperature DISTRIBUTION STATEMENT A – Approved for public release...distribution unlimited 4 Status of Modeling and Simulation • Existing data set for film cooling effectiveness consists of wall heat flux measurements • CFD

Investigation into the origin of parasitic absorption in GaInP|GaAs double heterostructures

NASA Astrophysics Data System (ADS)

Giannini, Nathan; Yang, Zhou; Albrecht, Alexander R.; Sheik-Bahae, Mansoor

2017-02-01

Despite achievements of extremely high external quantum efficiency (EQE), 99.5%, the net cooling of GaInP|GaAs double heterostructures (DHS) has never been realized. This is due to an unknown source of parasitic absorption. Prior studies have ruled out the possibility of the bulk absorption from the GaAs layer. Thus it is thought to be either at the air- GaInP interface, through the presence of dangling bonds, or in bulk GaInP through impurities. Using two-color thermallens calorimetry (based on the Z-scan technique), this study indicates that that the parasitic absorption likely originates from the GaInP bulk layers.

Laser Cooling the Diatomic Molecule CaH

NASA Astrophysics Data System (ADS)

Velasquez, Joe, III; Di Rosa, Michael

2014-06-01

To laser-cool a species, a closed (or nearly closed) cycle is required to dissipate translational energy through many directed laser-photon absorption and subsequent randomly-directed spontaneous emission events. Many atoms lend themselves to such a closed-loop cooling cycle. Attaining laser-cooled molecular species is challenging because of their inherently complex internal structure, yet laser-cooling molecules could lead to studies in interesting chemical dynamics among other applications. Typically, laser-cooled atoms are assembled into molecules through photoassociation or Feschbach resonance. CaH is one of a few molecules whose internal structure is quite atom-like, allowing a nearly closed cycle without the need for many repumping lasers. We will also present our work-to-date on laser cooling this molecule. We employ traditional pulsed atomic/molecular beam techniques with a laser vaporization source to generate species with well-defined translational energies over a narrow range of velocity. In this way, we can apply laser-cooling to most species in the beam along a single dimension (the beam's axis). This project is funded by the LDRD program of the Los Alamos National Laboratory.

Modeling Chilled-Water Storage System Components for Coupling to a Small Modular Reactor in a Nuclear Hybrid Energy System

NASA Astrophysics Data System (ADS)

Misenheimer, Corey Thomas

The intermittency of wind and solar power puts strain on electric grids, often forcing carbonbased and nuclear sources of energy to operate in a load-follow mode. Operating nuclear reactors in a load-follow fashion is undesirable due to the associated thermal and mechanical stresses placed on the fuel and other reactor components. Various Thermal Energy Storage (TES) elements and ancillary energy applications can be coupled to nuclear (or renewable) power sources to help absorb grid instabilities caused by daily electric demand changes and renewable intermittency, thereby forming the basis of a candidate Nuclear Hybrid Energy System (NHES). During the warmer months of the year in many parts of the country, facility air-conditioning loads are significant contributors to the increase in the daily peak electric demand. Previous research demonstrated that a stratified chilled-water storage tank can displace peak cooling loads to off-peak hours. Based on these findings, the objective of this work is to evaluate the prospect of using a stratified chilled-water storage tank as a potential TES reservoir for a nuclear reactor in a NHES. This is accomplished by developing time-dependent models of chilled-water system components, including absorption chillers, cooling towers, a storage tank, and facility cooling loads appropriate for a large office space or college campus, as a callable FORTRAN subroutine. The resulting TES model is coupled to a high-fidelity mPower-sized Small Modular Reactor (SMR) Simulator, with the goal of utilizing excess reactor capacity to operate several sizable chillers in order to keep reactor power constant. Chilled-water production via single effect, lithium bromide (LiBr) absorption chillers is primarily examined in this study, although the use of electric chillers is briefly explored. Absorption chillers use hot water or low-pressure steam to drive an absorption-refrigeration cycle. The mathematical framework for a high-fidelity dynamic absorption chiller model is presented. The transient FORTRAN model is grounded on time-dependent mass, species, and energy conservation equations. Due to the vast computational costs of the high-fidelity model, a low-fidelity absorption chiller model is formulated and calibrated to mimic the behavior of the high-fidelity model. Stratified chilled-water storage tank performance is characterized using Computational Fluid Dynamics (CFD). The geometry employed in the CFD model represents a 5-million-gallon storage tank currently in use at a North Carolina college campus. Simulation results reveal the laminar numerical model most closely aligns with actual tank charging and discharging data. A subsequent parametric study corroborates storage tank behavior documented throughout literature and industry. Two absorption chiller configurations are considered. The first involves bypassing lowpressure steam from the low-pressure turbine to absorption chillers during periods of excess reactor capacity in order to keep reactor power constant. Simulation results show steam conditions downstream of the turbine control valves are a strong function of turbine load, and absorption chiller performance is hindered by reduced turbine impulse pressures at reduced turbine demands. A more suitable configuration entails integrating the absorption chillers into a flash vessel system that is thermally coupled to a sensible heat storage system. The sensible heat storage system is able to maintain reactor thermal output constant at 100% and match turbine output with several different electric demand profiles. High-pressure condensate in the sensible heat storage system is dropped across a let-down orifice and flashed in an ideal separator. Generated steam is sent to a bank of absorption chillers. Simulation results show enough steam is available during periods of reduced turbine demand to power four large absorption chillers to charge a 5-million-gallon stratified chilled-water storage tank, which is used to offset cooling loads in an adjacent facility. The coupled TES systems operating in conjunction with an SMR comprise the foundation of a tightly coupled NHES.

Career Directions: HVACR Technician

ERIC Educational Resources Information Center

Moore, Pam

2005-01-01

Heating/ventilation/air conditioning/refrigeration (HVACR) technicians (also known as "heating and cooling technicians") are the people who install, maintain, test and repair the machines that control temperature, circulation, moisture and purity of air in residential, commercial and industrial buildings. These systems consist of a variety of…

7 CFR 3555.101 - Loan purposes.

Code of Federal Regulations, 2014 CFR

2014-01-01

...-wall carpeting, ovens, ranges, refrigerators, washing machines, clothes dryers, heating and cooling... the loan amount to be guaranteed. (c) Combination construction and permanent loan. Loan funds may be used and Rural Development will guarantee a “combination construction and permanent loan” as defined at...

Laser absorption of carbon fiber reinforced polymer with randomly distributed carbon fibers

NASA Astrophysics Data System (ADS)

Hu, Jun; Xu, Hebing; Li, Chao

2018-03-01

Laser processing of carbon fiber reinforced polymer (CFRP) is a non-traditional machining method which has many prospective applications. The laser absorption characteristics of CFRP are analyzed in this paper. A ray tracing model describing the interaction of the laser spot with CFRP is established. The material model contains randomly distributed carbon fibers which are generated using an improved carbon fiber placement method. It was found that CFRP has good laser absorption due to multiple reflections of the light rays in the material’s microstructure. The randomly distributed carbon fibers make the absorptivity of the light rays change randomly in the laser spot. Meanwhile, the average absorptivity fluctuation is obvious during movement of the laser. The experimental measurements agree well with the values predicted by the ray tracing model.

La Saturated Absorption Spectroscopy for Applications in Quantum Information

NASA Astrophysics Data System (ADS)

Becker, Patrick; Donoghue, Liz; Dungan, Kristina; Liu, Jackie; Olmschenk, Steven

2015-05-01

Quantum information may revolutionize computation and communication by utilizing quantum systems based on matter quantum bits and entangled light. Ions are excellent candidates for quantum bits as they can be well-isolated from unwanted external influences by trapping and laser cooling. Doubly-ionized lanthanum in particular shows promise for use in quantum information as it has infrared transitions in the telecom band, with low attenuation in standard optical fiber, potentially allowing for long distance information transfer. However, the hyperfine splittings of the lowest energy levels, required for laser cooling, have not been measured. We present progress and recent results towards measuring the hyperfine splittings of these levels in lanthanum by saturated absorption spectroscopy with a hollow cathode lamp. This research is supported by the Army Research Office, Research Corporation for Science Advancement, and Denison University.

Copernicus observations of Betelgeuse and Antares

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bernat, A.P.; Lambert, D.L.

1975-01-01

Copernicus observations of the M-supergiants, ..cap alpha.. Ori and ..cap alpha.. Sco, are presented. The Mg II H and K resonance lines are strongly in emission in both stars. The K line is highly asymmetric in both stars but the H line is symmetric. Upper limits for several other resonance lines are given for ..cap alpha.. Ori. The possibility is explored that the K line asymmetry is caused by overlying resonance lines of Mn I and Fe I formed in the cool circumstellar gas shells around these stars. Observations of the Mn I 4030--4033 A lines are used to showmore » that circumstellar shell absorption is too weak to explain the asymmetry. It is suggested that the absorption occurs in a cool turbulent region between the base of the circumstellar shell and the top of the chromosphere. (auth)« less

Sensitivity and resolution in frequency comb spectroscopy of buffer gas cooled polyatomic molecules

NASA Astrophysics Data System (ADS)

Changala, P. Bryan; Spaun, Ben; Patterson, David; Doyle, John M.; Ye, Jun

2016-12-01

We discuss the use of cavity-enhanced direct frequency comb spectroscopy in the mid-infrared region with buffer gas cooling of polyatomic molecules for high-precision rovibrational absorption spectroscopy. A frequency comb coupled to an optical enhancement cavity allows us to collect high-resolution, broad-bandwidth infrared spectra of translationally and rotationally cold (10-20 K) gas-phase molecules with high absorption sensitivity and fast acquisition times. The design and performance of the combined apparatus are discussed in detail. Recorded rovibrational spectra in the CH stretching region of several organic molecules, including vinyl bromide (CH_2CHBr), adamantane (C_{10}H_{16}), and diamantane (C_{14}H_{20}) demonstrate the resolution and sensitivity of this technique, as well as the intrinsic challenges faced in extending the frontier of high-resolution spectroscopy to large complex molecules.

Stellar and Circumstellar Properties of the Pre-Main-Sequence Binary GV Tau From Infrared Spectroscopy

DTIC Science & Technology

2008-09-20

surface gravity . With ourL-band spectra in order 25 (3.0450Y3.0865m;Fig. 1e), we detect strong HCN absorption (10% deep) and weaker C2H2 absorption in...Doppmann et al. 2005). The absorption lines of Na i and Mg i are particularly gravity and temperature sensitive, but in the opposite sense from each...other. For example, at cool effective temperatures (3200Y4500 K) and subdwarf surface gravities (3:5 log g 4:5) Na andMg lines both grow stronger as

Far-infrared spectra of CO2 clathrate hydrate frosts

NASA Technical Reports Server (NTRS)

Landry, J. C.; England, A. W.

1993-01-01

As a product of our interest in remote sensing of planetary ices, frost samples of CO2 clathrate hydrate were grown by depositing water vapor on a cooled surface and pressurizing the resulting water frost with CO2 gas. At pressures above the dissociation pressure of the clathrate, the samples exhibit an absorption peak at 75 cm (sup -1). At pressures below the dissociation pressure, the peak disappears. Since the free CO2 molecule does not have rotational or vibrational absorption in this region, the absorption is attributed to a CO2 rattling mode within a clathrate cage.

Cryogenic Thermal Absorptance Measurements on Small-Diameter Stainless Steel Tubing

NASA Technical Reports Server (NTRS)

Tuttle, James; Jahromi, Amir; Canavan, Edgar; DiPirro, Michael

2015-01-01

The Mid Infrared Instrument (MIRI) on the James Webb Space Telescope includes a mechanical cryocooler which cools its detectors to their 6 Kelvin operating temperature. The coolant gas flows through several meters of small-diameter stainless steel tubing, which is exposed to thermal radiation from its environment. Over much of its length this tubing is gold-plated to minimize the absorption of this radiant heat. In order to confirm that the cryocooler will meet MIRI's requirements, the thermal absorptance of this tubing was measured as a function of its environment temperature. We describe the measurement technique and present the results.

Cooling towers, the neglected energy conservations and money making machine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burger, R.

1996-12-31

The heat Rejection Industry defines a nominal cooling tower as circulating three gallons of water per minute (GPM) per ton of refrigeration from entering the tower at 95 {degrees}F, Hot Water temperature (HWT), Leaving at 85{degrees}F Cold Water Temperature (CWT) at a Design Wet Bulb of 70{degrees}F (WBT). Manufacturers then provide a selection chart based on various wet bulb temperatures and HWTs. The wet bulb fluctuates and varies throughout the world since it is the combination ambient temperature, relative humidity, and/or dew point. Different HWT and CWT requirements are usually charted as they change, so that the user can selectmore » the nominal cooling tower model recommended by the manufacturer. In the specification of cooling towers it is necessary to clearly understand the definition of nominal cooling tower, and to make sure the specification you need addressed can be met by the system you purchase. This should be tested prior to final acceptance.« less

Stress and Strain Distributions during Machining of Ti-6Al-4V at Ambient and Cryogenic Temperatures

NASA Astrophysics Data System (ADS)

Rahman, Md. Fahim

Dry and liquid nitrogen pre-cooled Ti-6Al-4V samples were machined at a cutting speed of 43.2 m/min and at low (0.1 mm/rev) to high (0.4 mm/rev) feed rates for understanding the effects of temperature and strain rate on chip microstructures. During cryogenic machining, it was observed that between feed rates of 0.10 and 0.30 mm/rev, a 25% pressure reduction on tool occurred. Smaller number of chips and low tool/chip contact time and temperature were observed (compared to dry machining under ambient conditions). An in-situ set-up that consisted of a microscope and a lathe was constructed and helped to propose a novel serrated chip formation mechanism when microstructures (strain localization) and surface roughness were considered. Dimpled fracture surfaces observed in high-speed-machined chips were formed due to stable crack propagation that was also recorded during in-situ machining. An instability criterion was developed that showed easier strain localization within the 0.10-0.30mm/rev feed rate range.

Experimental study of the use of refrigeration systems as cooling and heating systems in the production process of the VCO

NASA Astrophysics Data System (ADS)

Mulawarman, AANB; Arsana, M. E.; Temaja, I. W.; Sukadana, IBP

2018-01-01

Coconut oil extracted from the coconut milk obtained from fresh coconuts s often called virgin coconut oil (VCO). VCO is beneficial to health as an anti-oxidant and can lower HDL cholesterol in the blood while increasing blood LDL levels. In Indonesia most of VCO being produced on a small scale of home industries. Its production capacity still needs to be increased by improving production processes and implementing an appropriate technology accordingly. This research aims to conduct a study on making small-scale production machinery needed to produce VCO with reduced production time and improved quality of VCO in accordance with ISO 7381 quality criteria. The experimental results of the VCO machine has been develop and tested show good Coefficient of Performance of the system in amount of 3.93 and 2.8 for heating and cooling system respectively. Temperature of the VCO cooling chamber can be maintained in the range of 8°C to 10°C, as well as for heating, the reactor temperature can be maintained from 39°C to 42°C. The expected goal of this research developing a prototype of VCO production machine was done with ability to provide more efficient production process able to increase volume of VCO result by 23%.

Application of support vector machine method for the analysis of absorption spectra of exhaled air of patients with broncho-pulmonary diseases

NASA Astrophysics Data System (ADS)

Bukreeva, Ekaterina B.; Bulanova, Anna A.; Kistenev, Yury V.; Kuzmin, Dmitry A.; Tuzikov, Sergei A.; Yumov, Evgeny L.

2014-11-01

The results of the joint use of laser photoacoustic spectroscopy and chemometrics methods in gas analysis of exhaled air of patients with respiratory diseases (chronic obstructive pulmonary disease, pneumonia and lung cancer) are presented. The absorption spectra of exhaled breath of all volunteers were measured, the classification methods of the scans of the absorption spectra were applied, the sensitivity/specificity of the classification results were determined. It were obtained a result of nosological in pairs classification for all investigated volunteers, indices of sensitivity and specificity.

Cooling system for a gas turbine using a cylindrical insert having V-shaped notch weirs

DOEpatents

Grondahl, Clayton M.; Germain, Malcolm R.

1981-01-01

An improved cooling system for a gas turbine is disclosed. A plurality of V-shaped notch weirs are utilized to meter a coolant liquid from a pool of coolant into a plurality of platform and airfoil coolant channels formed in the buckets of the turbine. The V-shaped notch weirs are formed in a separately machined cylindrical insert and serve to desensitize the flow of coolant into the individual platform and airfoil coolant channels to design tolerances and non-uniform flow distribution.

Probing the Outflowing Multiphase Gas ∼1 kpc below the Galactic Center

DOE Office of Scientific and Technical Information (OSTI.GOV)

Savage, Blair D.; Kim, Tae-Sun; Wakker, Bart P.

Comparison of interstellar medium (ISM) absorption in the UV spectrum of LS 4825, a B1 Ib−II star d  = 21 ± 5 kpc from the Sun toward l  = 1.°67 and b  = −6.°63, with ISM absorption toward an aligned foreground star at d  < 7.0 ± 1.7 kpc, allows us to isolate and study gas associated with the Milky Way nuclear wind. Spectra from the Space Telescope Imaging Spectrograph show low-ionization absorption out to d  < 7 kpc (e.g., O i, C ii, Mg ii, Si ii, Fe ii, S ii) only between 0 and 40 km s{sup −1}, while absorption at d  > 7 kpc, ∼1 kpc below themore » Galactic plane, is complex and spans −290 to +94 km s{sup −1}. The intermediate and high ions Si iii, C iv, Si iv, and N v show extremely strong absorption with multiple components from −283 to 107 km s{sup −1}, implying that the ISM ∼1 kpc below the Galactic center has a substantial reservoir of plasma and more gas containing C iv and N v than in the Carina OB1 association at z  = 0 kpc. Abundances and physical conditions are presented for many absorption components. The high ion absorption traces cooling transition temperature plasma probably driven by the outflowing hot gas, while the extraordinarily large thermal pressure, p / k  ∼ 10{sup 5} cm{sup −3} K{sup −1}, in an absorption component at −114 km s{sup −1} probably arises from the ram pressure of the outflowing hot gas. The observations are consistent with a flow whose ionization structure in the high ions can be understood through a combination of nonequilibrium radiative cooling and turbulent mixing.« less

Thermal Management and Reliability of Automotive Power Electronics and Electric Machines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Narumanchi, Sreekant V; Bennion, Kevin S; Cousineau, Justine E

Low-cost, high-performance thermal management technologies are helping meet aggressive power density, specific power, cost, and reliability targets for power electronics and electric machines. The National Renewable Energy Laboratory is working closely with numerous industry and research partners to help influence development of components that meet aggressive performance and cost targets through development and characterization of cooling technologies, and thermal characterization and improvements of passive stack materials and interfaces. Thermomechanical reliability and lifetime estimation models are important enablers for industry in cost-and time-effective design.

Chalk point cooling tower project: effects of simulated saline cooling tower drift on woody species. Master's thesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Francis, B.A.

1977-07-01

Cooling towers of power plants are used to dissipate waste heat into the atmosphere. If saline water is used for cooling, a saline aerosol known as drift is released into the atmosphere. Drift effects on vegetation are not well known. To simulate drift for a field study, cooling tower basin water was sprayed thirty separate times during a 46-day period in 1975 on Virginia pine (Pinus virginiana), flowering dogwood (Cornus florida), tulip tree (Liriodendron tulipfera), and California privet (Ligustrum ovalifolium), Norway spruce (Picea abies), and white ash (Fraxinus americana) were added in 1976 and all trees were sprayed 43 timesmore » during a 59-day period. Only dogwood leaves showed significant injury. Absence of injury on other species was probably due to the ability of their leaves to exclude, or reduce absorption of, toxic concentrations of the ions supplied.« less

Effect of tropospheric aerosols upon atmospheric infrared cooling rates

NASA Technical Reports Server (NTRS)

Harshvardhan, MR.; Cess, R. D.

1978-01-01

The effect of tropospheric aerosols on atmospheric infrared cooling rates is investigated by the use of recent models of infrared gaseous absorption. A radiative model of the atmosphere that incorporates dust as an absorber and scatterer of infrared radiation is constructed by employing the exponential kernel approximation to the radiative transfer equation. Scattering effects are represented in terms of a single scattering albedo and an asymmetry factor. The model is applied to estimate the effect of an aerosol layer made of spherical quartz particles on the infrared cooling rate. Calculations performed for a reference wavelength of 0.55 microns show an increased greenhouse effect, where the net upward flux at the surface is reduced by 10% owing to the strongly enhanced downward emission. There is a substantial increase in the cooling rate near the surface, but the mean cooling rate throughout the lower troposphere was only 10%.

Experimental Investigation of Minimum Quantity Lubrication in Meso-scale Milling with Varying Tool Diameter

NASA Astrophysics Data System (ADS)

Yusof, M. Q. M.; Harun, H. N. S. B.; Bahar, R.

2018-01-01

Minimum quantity lubrication (MQL) is a method that uses a very small amount of liquid to reduce friction between cutting tool and work piece during machining. The implementation of MQL machining has become a viable alternative to flood cooling machining and dry machining. The overall performance has been evaluated during meso-scale milling of mild steel using different diameter milling cutters. Experiments have been conducted under two different lubrication condition: dry and MQL with variable cutting parameters. The tool wear and its surface roughness, machined surfaces microstructure and surface roughness were observed for both conditions. It was found from the results that MQL produced better results compared to dry machining. The 0.5 mm tool has been selected as the most optimum tool diameter to be used with the lowest surface roughness as well as the least flank wear generation. For the workpiece, it was observed that the cutting temperature possesses crucial effect on the microstructure and the surface roughness of the machined surface and bigger diameter tool actually resulted in higher surface roughness. The poor conductivity of the cutting tool may be one of reasons behind.

Cooling options for high-average-power laser mirrors

NASA Astrophysics Data System (ADS)

Vojna, D.; Slezak, O.; Lucianetti, A.; Mocek, T.

2015-01-01

Thermally-induced deformations of steering mirrors reflecting 100 J/10 Hz laser pulses in vacuum have been analyzed. This deformation is caused by the thermal stress arisen due to parasitic absorption of 1 kW square-shaped flat-top laser beam in the dielectric multi-layer structure. Deformation depends on amount of absorbed power and geometry of the mirror as well as on the heat removal scheme. In our calculations, the following percentages of absorption of the incident power have been used: 1%, 0.5% and 0.1%. The absorbed power has been considered to be much higher than that expected in reality to assess the worst case scenario. Rectangular and circular mirrors made of zerodur (low thermal expansion glass) were considered for these simulations. The effect of coating layers on induced deformations has been neglected. Induced deformation of the mirror surface can significantly degrade the quality of the laser beam in the beam delivery system. Therefore, the proper design of the cooling scheme for the mirror in order to minimize the deformations is needed. Three possible cooling schemes of the mirror have been investigated. The first one takes advantage of a radiation cooling of the mirror and a copper heatsink fixed to the rear face of the mirror, the second scheme is based on additional heat conduction provided by flexible copper wires connected to the mirror holder, and the last scheme combines two above mentioned methods.

Phase change material thermal capacitor clothing

NASA Technical Reports Server (NTRS)

Buckley, Theresa M. (Inventor)

2005-01-01

An apparatus and method for metabolic cooling and insulation of a user in a cold environment. In its preferred embodiment the apparatus is a highly flexible composite material having a flexible matrix containing a phase change thermal storage material. The apparatus can be made to heat or cool the body or to act as a thermal buffer to protect the wearer from changing environmental conditions. The apparatus may also include an external thermal insulation layer and/or an internal thermal control layer to regulate the rate of heat exchange between the composite and the skin of the wearer. Other embodiments of the apparatus also provide 1) a path for evaporation or direct absorption of perspiration from the skin of the wearer for improved comfort and thermal control, 2) heat conductive pathways within the material for thermal equalization, 3) surface treatments for improved absorption or rejection of heat by the material, and 4) means for quickly regenerating the thermal storage capacity for reuse of the material. Applications of the composite materials are also described which take advantage of the composite's thermal characteristics. The examples described include a diver's wet suit, ski boot liners, thermal socks, gloves and a face mask for cold weather activities, and a metabolic heating or cooling blanket useful for treating hypothermia or fever patients in a medical setting and therapeutic heating or cooling orthopedic joint supports.

Phase change thermal control materials, method and apparatus

NASA Technical Reports Server (NTRS)

Buckley, Theresa M. (Inventor)

2001-01-01

An apparatus and method for metabolic cooling and insulation of a user in a cold environment. In its preferred embodiment the apparatus is a highly flexible composite material having a flexible matrix containing a phase change thermal storage material. The apparatus can be made to heat or cool the body or to act as a thermal buffer to protect the wearer from changing environmental conditions. The apparatus may also include an external thermal insulation layer and/or an internal thermal control layer to regulate the rate of heat exchange between the composite and the skin of the wearer. Other embodiments of the apparatus also provide 1) a path for evaporation or direct absorption of perspiration from the skin of the wearer for improved comfort and thermal control, 2) heat conductive pathways within the material for thermal equalization, 3) surface treatments for improved absorption or rejection of heat by the material, and 4) means for quickly regenerating the thermal storage capacity for reuse of the material. Applications of the composite materials are also described which take advantage of the composite's thermal characteristics. The examples described include a diver's wet suit, ski boot liners, thermal socks, gloves and a face mask for cold weather activities, and a metabolic heating or cooling blanket useful for treating hypothermia or fever patients in a medical setting and therapeutic heating or cooling orthopedic joint supports.

A Superfluid Pulse Tube Refrigerator Without Moving Parts for Sub-Kelvin Cooling

NASA Technical Reports Server (NTRS)

Miller, Franklin K.

2012-01-01

A report describes a pulse tube refrigerator that uses a mixture of He-3 and superfluid He-4 to cool to temperatures below 300 mK, while rejecting heat at temperatures up to 1.7 K. The refrigerator is driven by a novel thermodynamically reversible pump that is capable of pumping the He-3 He-4 mixture without the need for moving parts. The refrigerator consists of a reversible thermal magnetic pump module, two warm heat exchangers, a recuperative heat exchanger, two cold heat exchangers, two pulse tubes, and an orifice. It is two superfluid pulse tubes that run 180 out of phase. All components of this machine except the reversible thermal pump have been demonstrated at least as proof-of-concept physical models in previous superfluid Stirling cycle machines. The pump consists of two canisters packed with pieces of gadolinium gallium garnet (GGG). The canisters are connected by a superleak (a porous piece of VYCOR glass). A superconducting magnetic coil surrounds each of the canisters.

Simulation of cracking cores when molding piston components

NASA Astrophysics Data System (ADS)

Petrenko, Alena; Soukup, Josef

2014-08-01

The article deals with pistons casting made from aluminum alloy. Pistons are casting at steel mold with steel core. The casting is provided by gravity casting machine. The each machine is equipped by two metal molds, which are preheated above temperature 160 °C before use. The steel core is also preheated by flame. The metal molds and cores are heated up within the casting process. The temperature of the metal mold raise up to 200 °C and temperature of core is higher. The surface of the core is treated by nitration. The mold and core are cooled down by water during casting process. The core is overheated and its top part is finally cracked despite its intensive water-cooling. The life time cycle of the core is decreased to approximately 5 to 15 thousands casting, which is only 15 % of life time cycle of core for production of other pistons. The article presents the temperature analysis of the core.

Influence of Cooling Condition on the Performance of Grinding Hardened Layer in Grind-hardening

NASA Astrophysics Data System (ADS)

Wang, G. C.; Chen, J.; Xu, G. Y.; Li, X.

2018-02-01

45# steel was grinded and hardened on a surface grinding machine to study the effect of three different cooling media, including emulsion, dry air and liquid nitrogen, on the microstructure and properties of the hardened layer. The results show that the microstructure of material surface hardened with emulsion is pearlite and no hardened layer. The surface roughness is small and the residual stress is compressive stress. With cooling condition of liquid nitrogen and dry air, the specimen surface are hardened, the organization is martensite, the surface roughness is also not changed, but high hardness of hardened layer and surface compressive stress were obtained when grinding using liquid nitrogen. The deeper hardened layer grinded with dry air was obtained and surface residual stress is tensile stress. This study provides an experimental basis for choosing the appropriate cooling mode to effectively control the performance of grinding hardened layer.

Design, Fabrication, and Testing of an Auxiliary Cooling System for Jet Engines

NASA Technical Reports Server (NTRS)

Leamy, Kevin; Griffiths, Jim; Andersen, Paul; Joco, Fidel; Laski, Mark; Balser, Jeffrey (Technical Monitor)

2001-01-01

This report summarizes the technical effort of the Active Cooling for Enhanced Performance (ACEP) program sponsored by NASA. It covers the design, fabrication, and integrated systems testing of a jet engine auxiliary cooling system, or turbocooler, that significantly extends the use of conventional jet fuel as a heat sink. The turbocooler is designed to provide subcooled cooling air to the engine exhaust nozzle system or engine hot section. The turbocooler consists of three primary components: (1) a high-temperature air cycle machine driven by engine compressor discharge air, (2) a fuel/ air heat exchanger that transfers energy from the hot air to the fuel and uses a coating to mitigate fuel deposits, and (3) a high-temperature fuel injection system. The details of the turbocooler component designs and results of the integrated systems testing are documented. Industry Version-Data and information deemed subject to Limited Rights restrictions are omitted from this document.

Stirling cryocooler test results and design model verification

NASA Astrophysics Data System (ADS)

Shimko, Martin A.; Stacy, W. D.; McCormick, John A.

A long-life Stirling cycle cryocooler being developed for spaceborne applications is described. The results from tests on a preliminary breadboard version of the cryocooler used to demonstrate the feasibility of the technology and to validate the generator design code used in its development are presented. This machine achieved a cold-end temperature of 65 K while carrying a 1/2-W cooling load. The basic machine is a double-acting, flexure-bearing, split Stirling design with linear electromagnetic drives for the expander and compressors. Flat metal diaphragms replace pistons for sweeping and sealing the machine working volumes. The double-acting expander couples to a laminar-channel counterflow recuperative heat exchanger for regeneration. The PC-compatible design code developed for this design approach calculates regenerator loss, including heat transfer irreversibilities, pressure drop, and axial conduction in the regenerator walls. The code accurately predicted cooler performance and assisted in diagnosing breadboard machine flaws during shakedown and development testing.

Advanced Design Heat PumpRadiator for EVA Suits

NASA Technical Reports Server (NTRS)

Izenson, Michael G.; Chen, Weibo; Passow, Christian; Phillips, Scott; Trevino, Luis

2009-01-01

Absorption cooling using a LiCl/water heat pump can enable lightweight and effective thermal control for EVA suits without venting water to the environment. The key components in the system are an absorber/radiator that rejects heat to space and a flexible evaporation cooling garment that absorbs heat from the crew member. This paper describes progress in the design, development, and testing of the absorber/radiator and evaporation cooling garment. New design concepts and fabrication approaches will significantly reduce the mass of the absorber/radiator. We have also identified materials and demonstrated fabrication approaches for production of a flexible evaporation cooling garment. Data from tests of the absorber/radiator s modular components have validated the design models and allowed predictions of the size and weight of a complete system.

DOE Office of Scientific and Technical Information (OSTI.GOV)

CHUGH, Devesh; Gluesenkamp, Kyle R; Abdelaziz, Omar

In this study, development of a novel system for combined water heating, dehumidification, and space evaporative cooling is discussed. Ambient water vapor is used as a working fluid in an open system. First, water vapor is absorbed from an air stream into an absorbent solution. The latent heat of absorption is transferred into the process water that cools the absorber. The solution is then regenerated in the desorber, where it is heated by a heating fluid. The water vapor generated in the desorber is condensed and its heat of phase change is transferred to the process water in the condenser.more » The condensed water can then be used in an evaporative cooling process to cool the dehumidified air exiting the absorber, or it can be drained if primarily dehumidification is desired. Essentially, this open absorption cycle collects space heat and transfers it to process water. This technology is enabled by a membrane-based absorption/desorption process in which the absorbent is constrained by hydrophobic vapor-permeable membranes. Constraining the absorbent film has enabled fabrication of the absorber and desorber in a plate-and-frame configuration. An air stream can flow against the membrane at high speed without entraining the absorbent, which is a challenge in conventional dehumidifiers. Furthermore, the absorption and desorption rates of an absorbent constrained by a membrane are greatly enhanced. Isfahani and Moghaddam (Int. J. Heat Mass Transfer, 2013) demonstrated absorption rates of up to 0.008 kg/m2s in a membrane-based absorber and Isfahani et al. (Int. J. Multiphase Flow, 2013) have reported a desorption rate of 0.01 kg/m2s in a membrane-based desorber. The membrane-based architecture also enables economical small-scale systems, novel cycle configurations, and high efficiencies. The absorber, solution heat exchanger, and desorber are fabricated on a single metal sheet. In addition to the open arrangement and membrane-based architecture, another novel feature of the cycle is recovery of the solution heat energy exiting the desorber by process water (a process-solution heat exchanger ) rather than the absorber exiting solution (the conventional solution heat exchanger ). This approach has enabled heating the process water from an inlet temperature of 15 C to 57 C (conforming to the DOE water heater test standard) and interfacing the process water with absorbent on the opposite side of a single metal sheet encompassing the absorber, process-solution heat exchanger, and desorber. The system under development has a 3.2 kW water heating capacity and a target thermal coefficient of performance (COP) of 1.6.« less

Electron cooling of a bunched ion beam in a storage ring

NASA Astrophysics Data System (ADS)

Zhao, He; Mao, Lijun; Yang, Jiancheng; Xia, Jiawen; Yang, Xiaodong; Li, Jie; Tang, Meitang; Shen, Guodong; Ma, Xiaoming; Wu, Bo; Wang, Geng; Ruan, Shuang; Wang, Kedong; Dong, Ziqiang

2018-02-01

A combination of electron cooling and rf system is an effective method to compress the beam bunch length in storage rings. A simulation code based on multiparticle tracking was developed to calculate the bunched ion beam cooling process, in which the electron cooling, intrabeam scattering (IBS), ion beam space-charge field, transverse and synchrotron motion are considered. Meanwhile, bunched ion beam cooling experiments have been carried out in the main cooling storage ring (CSRm) of the Heavy Ion Research Facility in Lanzhou, to investigate the minimum bunch length obtained by the cooling method, and study the dependence of the minimum bunch length on beam and machine parameters. The experiments show comparable results to those from simulation. Based on these simulations and experiments, we established an analytical model to describe the limitation of the bunch length of the cooled ion beam. It is observed that the IBS effect is dominant for low intensity beams, and the space-charge effect is much more important for high intensity beams. Moreover, the particles will not be bunched for much higher intensity beam. The experimental results in CSRm show a good agreement with the analytical model in the IBS dominated regime. The simulation work offers us comparable results to those from the analytical model both in IBS dominated and space-charge dominated regimes.

Responsive materials: A novel design for enhanced machine-augmented composites

PubMed Central

Bafekrpour, Ehsan; Molotnikov, Andrey; Weaver, James C.; Brechet, Yves; Estrin, Yuri

2014-01-01

The concept of novel responsive materials with a displacement conversion capability was further developed through the design of new machine-augmented composites (MACs). Embedded converter machines and MACs with improved geometry were designed and fabricated by multi-material 3D printing. This technique proved to be very effective in fabricating these novel composites with tuneable elastic moduli of the matrix and the embedded machines and excellent bonding between them. Substantial improvement in the displacement conversion efficiency of the new MACs over the existing ones was demonstrated. Also, the new design trebled the energy absorption of the MACs. Applications in energy absorbers as well as mechanical sensors and actuators are thus envisaged. A further type of MACs with conversion ability, viz. conversion of compressive displacements to torsional ones, was also proposed. PMID:24445490

Experimental studies of a zeeman-tuned xenon laser differential absorption apparatus.

PubMed

Linford, G J

1973-06-01

A Zeeman-tuned cw xenon laser differential absorption device is described. The xenon laser was tuned by axial magnetic fields up to 5500 G generated by an unusually large water-cooled dc solenoid. Xenon laser lines at 3.37 micro, 3.51 micro, and 3.99 micro were tuned over ranges of 6 A, 6 A, and 11 A, respectively. To date, this apparatus has been used principally to study the details of formaldehyde absorption lines lying near the 3 .508-micro xenon laser transition. These experiments revealed that the observed absorption spectrum of formaldehyde exhibits a sufficiently unique spectral structure that the present technique may readily be used to measure relative concentrations of formaldehyde in samples of polluted air.

Thermal properties of borate crystals for high power optical parametric chirped-pulse amplification.

PubMed

Riedel, R; Rothhardt, J; Beil, K; Gronloh, B; Klenke, A; Höppner, H; Schulz, M; Teubner, U; Kränkel, C; Limpert, J; Tünnermann, A; Prandolini, M J; Tavella, F

2014-07-28

The potential of borate crystals, BBO, LBO and BiBO, for high average power scaling of optical parametric chirped-pulse amplifiers is investigated. Up-to-date measurements of the absorption coefficients at 515 nm and the thermal conductivities are presented. The measured absorption coefficients are a factor of 10-100 lower than reported by the literature for BBO and LBO. For BBO, a large variation of the absorption coefficients was found between crystals from different manufacturers. The linear and nonlinear absorption coefficients at 515 nm as well as thermal conductivities were determined for the first time for BiBO. Further, different crystal cooling methods are presented. In addition, the limits to power scaling of OPCPAs are discussed.

Broad Balmer-Line Absorption in SDSS J172341.10+555340.5

NASA Astrophysics Data System (ADS)

Aoki, Kentaro

2010-10-01

We present the discovery of Balmer-line absorption from Hα to H9 in an iron low-ionizaton broad absorption line (FeLoBAL) quasar, SDSS J172341.10+555340.5, by near-infrared spectroscopy with the Cooled Infrared Spectrograph and Camera for OHS (CISCO) attached to the Subaru Telescope. The redshift of the Balmer-line absorption troughs is 2.0530±0.0003, and it is blueshifted by 5370 km s-1 from the Balmer emission lines. It is more than 4000 km s-1 blueshifted from the previously known UV absorption lines. We detected relatively strong (EWrest = 20 Å) [OIII] emission lines that are similar to those found in other broad absorption line quasars with Balmer-line absorption. We also derived the column density of neutral hydrogen of 5.2 × 1017 cm-2 by using the curve of growth and taking account of Lyα trapping. We searched for UV absorption lines that had the same redshift with Balmer-line absorption, and found Ali III and Fe III absorption lines at z = 2.053 that correspond to previously unidentified absorption lines, and the presence of other blended troughs that were difficult to identify.

Empirical determination of low J values of 13CH4 transitions from jet cooled and 80 K cell spectra in the icosad region (7170-7367 cm-1)

NASA Astrophysics Data System (ADS)

Votava, O.; Mašát, M.; Pracna, P.; Mondelain, D.; Kassi, S.; Liu, A. W.; Hu, S. M.; Campargue, A.

2014-12-01

The absorption spectrum of 13CH4 was recorded at two low temperatures in the icosad region near 1.38 μm, using direct absorption tunable diode lasers. Spectra were obtained using a cryogenic cell cooled at liquid nitrogen temperature (80 K) and a supersonic jet providing a 32 K rotational temperature in the 7173-7367 cm-1 and 7200-7354 cm-1 spectral intervals, respectively. Two lists of 4498 and 339 lines, including absolute line intensities, were constructed from the 80 K and jet spectra, respectively. All the transitions observed in jet conditions were observed at 80 K. From the temperature variation of their line intensities, the corresponding lower state energy values were determined. The 339 derived empirical values of the J rotational quantum number are found close to integer values and are all smaller than 4, as a consequence of the efficient rotational cooling. Six R(0) transitions have been identified providing key information on the origins of the vibrational bands which contribute to the very congested and not yet assigned 13CH4 spectrum in the considered region of the icosad.

Cool neutral hydrogen in the direction of an anonymous OB association

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bania, T.M.

1983-08-01

H I self-absorption is seen in the direction l = 55./sup 0/6 probably physically associated with an anonymous OB association which has the Cepheid GY Sagittae as a member. The cool H I is in two clouds at least 15 pc in diameter located 3.25 kpc from the Sun. If their temperature is approx. =50 K, the cloud masses are approx. =10/sup 3/ M/sub sun/. The neutral atomic hydrogen clouds are probably warm envelopes surrounding cold molecular cloud cores because CO observations in this region show two molecular clouds nearly coincident with the absorbing H i gas. Since the OBmore » association is only approx. =10/sup 7/ years old, these clouds are likely to be part of the original cloud complex from which the stellar cluster formed. The H i clouds are part of the larger Arecibo survey of self-absorption which suggests that many of the Arecibo clouds are associated with heretofore unidentified star clusters. Even if this is generally not the case, the Arecibo objects have accurate kinematic distances and thus provide a new sample of cool H I clouds whose thermodynamic properties can be studied.« less

Solar powered absorption cycle heat pump using phase change materials for energy storage

NASA Technical Reports Server (NTRS)

Middleton, R. L.

1972-01-01

Solar powered heating and cooling system with possible application to residential homes is described. Operating principles of system are defined and illustration of typical energy storage and exchange system is provided.

The outer atmospheres of cool M giants: High-dispersion ultraviolet spectra of Rho Per, 2 Cen, and g Her

NASA Technical Reports Server (NTRS)

Eaton, Joel A.; Johnson, Hollis R.

1986-01-01

Long duration IUE spectra were obtained to extend coverage of cool giants studied in the ultraviolet at high dispersion to M6. The chromospheric spectra of the three stars, which consist of a profusion of Fe II lines and a few lines of Mg II, Mg I, Al II, C II, C I, Cr II, and Fe I, are remarkably similar, both among themselves and with respect to stars of earlier spectral type. These lines present a picture of a warm chromosphere that is static in the average but may be far from uniform in density and ionization. The Mg II emission lines of 2 Cen show 2 unresolved absorption components, the shorter at the velocity of the local interstellar medium. The longer is blueshifted from the star by 12 to 18 km/sec and must be one of very few observed shell lines uncontaminated by interstellar absorption.

The absorption of sound by perforated linings

NASA Astrophysics Data System (ADS)

Hughes, I. J.; Dowling, A. P.

1990-09-01

This paper describes a practical application for sound-absorbent perforated screen with a bias flow through the screen. It is postulated that, if a perforated liner with a bias flow of cooling air through the liner is inserted in the afterburner section of a jet engine, all the incident sound may be absorbed at a particular frequency. Experimental results are presented on the absorptive properties of plane liners with circular apertures, showing an agreement with the theoretical model.

Research Proposal for the Design and Engineering Phase of a Solar Heating and Cooling System Experiment at the Warner Robins Public Library, Warner Robins, Georgia. Submitted to the United States Energy Research and Development Administration.

ERIC Educational Resources Information Center

Phillips, Warren H.; And Others

A number of reasons are advanced to include a solar heating and cooling experiment in a library building. The unique aspects of the experiment are to be a seasonally adjustable collector tilt and testing of a new generation of absorption air conditioners. After a brief description of the proposed experiment, the proposal contains forms filed by…

Solar heating and cooling system installed at Columbus, Ohio

NASA Technical Reports Server (NTRS)

1980-01-01

The Solar Energy System was installed as a part of a new construction of a college building. The building will house classrooms and laboratories, administrative offices and three lecture halls. The Solar Energy System consists of 4,096 square feet (128 panels) Owens/Illinois Evacuated Glass Tube Collector Subsystem, and a 5,000 gallon steel tank below ground storage system. Hot water is circulated between the collectors and storage tank, passing through a water/lithium bromide absorption chiller to cool the building.

Modeling of a Von Platen-Munters diffusion absorption refrigeration cycle

NASA Astrophysics Data System (ADS)

Agostini, Bruno; Agostini, Francesco; Habert, Mathieu

2016-09-01

This article presents a thermodynamical model of a Von-Platen diffusion absorption refrigeration cycle for power electronics applications. It is first validated by comparison with data available in the literature for the classical water-ammonia-helium cycle for commercial absorption fridges. Then new operating conditions corresponding to specific ABB applications, namely high ambient temperature and new organic fluids combinations compatible with aluminium are simulated and discussed. The target application is to cool power electronics converters in harsh environments with high ambient temperature by providing refrigeration without compressor, for passive components losses of about 500 W, with a compact and low cost solution.

A Broadband Micro-Machined Far-Infrared Absorber

NASA Technical Reports Server (NTRS)

Wollack, E. J.; Datesman, A. M.; Jhabvala, C. A.; Miller, K. H.; Quijada, M. A.

2016-01-01

The experimental investigation of a broadband far-infrared meta-material absorber is described. The observed absorptance is greater than 0.95 from 1 to 20 terahertz (300-15 microns) over a temperature range spanning 5-300 degrees Kelvin. The meta-material, realized from an array of tapers approximately 100 microns in length, is largely insensitive to the detailed geometry of these elements and is cryogenically compatible with silicon-based micro-machined technologies. The electromagnetic response is in general agreement with a physically motivated transmission line model.

Design and Economic Potential of an Integrated High-Temperature Fuel Cell and Absorption Chiller Combined Cooling, Heat, and Power System

NASA Astrophysics Data System (ADS)

Hosford, Kyle S.

Clean distributed generation power plants can provide a much needed balance to our energy infrastructure in the future. A high-temperature fuel cell and an absorption chiller can be integrated to create an ideal combined cooling, heat, and power system that is efficient, quiet, fuel flexible, scalable, and environmentally friendly. With few real-world installations of this type, research remains to identify the best integration and operating strategy and to evaluate the economic viability and market potential of this system. This thesis informs and documents the design of a high-temperature fuel cell and absorption chiller demonstration system at a generic office building on the University of California, Irvine (UCI) campus. This work details the extension of prior theoretical work to a financially-viable power purchase agreement (PPA) with regard to system design, equipment sizing, and operating strategy. This work also addresses the metering and monitoring for the system showcase and research and details the development of a MATLAB code to evaluate the economics associated with different equipment selections, building loads, and economic parameters. The series configuration of a high-temperature fuel cell, heat recovery unit, and absorption chiller with chiller exhaust recirculation was identified as the optimal system design for the installation in terms of efficiency, controls, ducting, and cost. The initial economic results show that high-temperature fuel cell and absorption chiller systems are already economically competitive with utility-purchased generation, and a brief case study of a southern California hospital shows that the systems are scalable and viable for larger stationary power applications.

Water absorption characteristic of interlocking compressed earth brick units

NASA Astrophysics Data System (ADS)

Bakar, B. H. Abu; Saari, S.; Surip, N. A.

2017-10-01

This study aims to investigate the water absorption characteristic of interlocking compressed earth brick (ICEB) units. Apart from compressive strength, water absorption is an important property in masonry. This property can affect the quality of the brick itself and the bond strength between the brick and mortar in masonry structures and can result in reducing its strength properties. The units were tested for 24 h water absorption and 5 h boiling water absorption. A total of 170 ICEB units from four ICEB types underwent both tests. For the 24 h water absorption, the ICEB units were dried in the oven for 24 h and then cooled before being weighed. Thereafter, each brick was immersed in water for 24 h and weighed. The same specimens used for the 24 h water absorption test were re-used for the 5 h boiling water absorption test. After completing the 24 h water absorption test, the brick was boiled for 5-hours and weighed. The highest water absorption for the ICEBs in the 24-hour water absorption and 5 h boiling water absorption tests are 15.09% and 17.18%, respectively. The half brick has the highest water absorption (15.87%), whereas the beam brick has the lowest (13.20%). The water absorption of an ICEB unit is higher than that of normal bricks, although the water absorption of the former remains below the maximum rate of the brick water absorption (21%).

National Synchrotron Light Source annual report 1991

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hulbert, S.L.; Lazarz, N.M.

1992-04-01

This report discusses the following research conducted at NSLS: atomic and molecular science; energy dispersive diffraction; lithography, microscopy and tomography; nuclear physics; UV photoemission and surface science; x-ray absorption spectroscopy; x-ray scattering and crystallography; x-ray topography; workshop on surface structure; workshop on electronic and chemical phenomena at surfaces; workshop on imaging; UV FEL machine reviews; VUV machine operations; VUV beamline operations; VUV storage ring parameters; x-ray machine operations; x-ray beamline operations; x-ray storage ring parameters; superconducting x-ray lithography source; SXLS storage ring parameters; the accelerator test facility; proposed UV-FEL user facility at the NSLS; global orbit feedback systems; and NSLSmore » computer system.« less

Large atom number Bose-Einstein condensate machines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Streed, Erik W.; Chikkatur, Ananth P.; Gustavson, Todd L.

2006-02-15

We describe experimental setups for producing large Bose-Einstein condensates of {sup 23}Na and {sup 87}Rb. In both, a high-flux thermal atomic beam is decelerated by a Zeeman slower and is then captured and cooled in a magneto-optical trap. The atoms are then transferred into a cloverleaf-style Ioffe-Pritchard magnetic trap and cooled to quantum degeneracy with radio-frequency-induced forced evaporation. Typical condensates contain 20x10{sup 6} atoms. We discuss the similarities and differences between the techniques used for producing large {sup 87}Rb and {sup 23}Na condensates in the context of nearly identical setups.

Rubber hose surface defect detection system based on machine vision

NASA Astrophysics Data System (ADS)

Meng, Fanwu; Ren, Jingrui; Wang, Qi; Zhang, Teng

2018-01-01

As an important part of connecting engine, air filter, engine, cooling system and automobile air-conditioning system, automotive hose is widely used in automobile. Therefore, the determination of the surface quality of the hose is particularly important. This research is based on machine vision technology, using HALCON algorithm for the processing of the hose image, and identifying the surface defects of the hose. In order to improve the detection accuracy of visual system, this paper proposes a method to classify the defects to reduce misjudegment. The experimental results show that the method can detect surface defects accurately.

Interpretation of the prominence differential emissions measure for 3 geometries

NASA Technical Reports Server (NTRS)

Schmahl, E. J.; Orrall, F. Q.

1986-01-01

Researchers have used prominence extreme ultraviolet line intensities observed from Skylab to derive the differential emission measure Q(T) in the prominence-corona (PC) interface from 3 x 10,000 to 3 times 1 million K, including the effects of Lyman Continuum absorption. Using lines both shortward and longward of the Lyman limit, researchers have estimated the importance of absorption as function of temperature. The magnitude of the absorption, as well as its rate of increase as a function of temperature, place limits on the thread scales and the character of the interfilar medium. Researchers have calculated models based on three assumed geometries: (1) threads with hot sheaths and cool cores; (2) isothermal threads; and (3) threads with longitudinal temperature gradients along the magnetic field. Comparison of the absorption computed from these models with the observed absorption in prominences shows that none of the geometries is totally satisfactory.

Comparison of simulated and experimental results of temperature distribution in a closed two-phase thermosyphon cooling system

NASA Astrophysics Data System (ADS)

Shaanika, E.; Yamaguchi, K.; Miki, M.; Ida, T.; Izumi, M.; Murase, Y.; Oryu, T.; Yanamoto, T.

2017-12-01

Superconducting generators offer numerous advantages over conventional generators of the same rating. They are lighter, smaller and more efficient. Amongst a host of methods for cooling HTS machinery, thermosyphon-based cooling systems have been employed due to their high heat transfer rate and near-isothermal operating characteristics associated with them. To use them optimally, it is essential to study thermal characteristics of these cryogenic thermosyphons. To this end, a stand-alone neon thermosyphon cooling system with a topology resembling an HTS rotating machine was studied. Heat load tests were conducted on the neon thermosyphon cooling system by applying a series of heat loads to the evaporator at different filling ratios. The temperature at selected points of evaporator, adiabatic tube and condenser as well as total heat leak were measured. A further study involving a computer thermal model was conducted to gain further insight into the estimated temperature distribution of thermosyphon components and heat leak of the cooling system. The model employed boundary conditions from data of heat load tests. This work presents a comparison between estimated (by model) and experimental (measured) temperature distribution in a two-phase cryogenic thermosyphon cooling system. The simulation results of temperature distribution and heat leak compared generally well with experimental data.

In-vivo experimental evaluation of nonablative skin remodeling using a 1.54-μm laser with surface cooling

NASA Astrophysics Data System (ADS)

Mordon, Serge R.; Capon, Alexandre; Creusy, Collette; Fleurisse, Laurence; Buys, Bruno; Faucheux, Marc A.; Servell, Pascal

2000-05-01

Selective dermal remodeling using diode or 1.32 micrometer Nd:YAG lasers has been recently proposed for skin rejuvenation. This new technique consists in inducing collagen tightening and/or neocollagen synthesis without significant damage of the overlying epidermis. Such an approach requires (1) a cooling system in order to target dermal collagen with relatively good protection of the epidermal layer, (2) a specific wavelength for confining the thermal damage into the upper dermis (100 to 400 micrometer). Based on previous studies, demonstrating a better water absorption and a reduced melanin absorption at 1.54 micrometer compared to the 1.32 micrometer, this experimental study aimed to evaluate a new laser (co-doped Yb-Er:phosphate glass material, Aramis, Quantel-France) emitting at 1.54 micrometer. This laser was used in combination with the Dermacool system (Dermacool, Mableton, USA) in order to achieve epidermis cooling before, during and after irradiation. Male hairless rats were used for the study. Pulse train irradiation (1.1 J, 3 Hz, 30 pulses) and different cooling temperatures (+5 degree(s)C, 0 degree(s)C, -5 degree(s)C) were screened with clinical examination and histological evaluation at 1, 3, and 7 days after laser irradiation. The clinical effects showed that pulse train irradiation produced reproducible epidermal preservation and confinement of the thermal damage into the dermis. The different cooling temperatures did not provide detectable differences in terms of size and depth of thermal damage. New collagen synthesis was confirmed by a marked fibroblastic proliferation, detected in the lower dermis at D3 and clearly seen in the upper dermis at D7. This new laser appears to be a promising new tool for the treatment of skin laxity, solar elastosis, facial rhytids and mild reduction of wrinkles.

Characterization of selective solar absorber under high vacuum.

PubMed

Russo, Roberto; Monti, Matteo; di Giamberardino, Francesco; Palmieri, Vittorio G

2018-05-14

Total absorption and emission coefficients of selective solar absorbers are measured under high vacuum conditions from room temperature up to stagnation temperature. The sample under investigation is illuminated under vacuum @1000W/m 2 and the sample temperature is recorded during heat up, equilibrium and cool down. During stagnation, the absorber temperature exceeds 300°C without concentration. Data analysis allows evaluating the solar absorptance and thermal emittance at different temperatures. These in turn are useful to predict evacuated solar panel performances at operating conditions.

Three Dimensional Reconstruction Algorithm for Imaging Pathophysiological Signals Within Breast Tissue Using Near Infrared Light

DTIC Science & Technology

2006-07-01

months.31 A heated mixture of water, gelatin (G2625, Sigma Inc.), India ink (for absorption), and titanium dioxide powder (for scatter) (TiO2, Sigma Inc...for absorption, and titanium dioxide powder for scat- ter TiO2, Sigma Inc. that are solidified by cooling to room temperature. Optically...2713-2727. 8. Bolin, F.P., Preuss, L. E., Taylor, R. C., Ference, R. J, Refractive index of some mammalian tissue using a fiber optic cladding method

Recent Advances in SRS on Hydrogen Isotope Separation Using Thermal Cycling Absorption Process

DOE PAGES

Xiao, Xin; Sessions, Henry T.; Heung, L. Kit

2015-02-01

The recent Thermal Cycling Absorption Process (TCAP) advances at Savannah River Site (SRS) include compressor-free concept for heating/cooling, push and pull separation using an active inverse column, and compact column design. The new developments allow significantly higher throughput and better reliability from 1/10th of the current production system’s footprint while consuming 60% less energy. Various versions are derived in the meantime for external customers to be used in fusion energy projects and medical isotope production.

Upgrades of edge, divertor and scrape-off layer diagnostics of W7-X for OP1.2

DOE PAGES

Hathiramani, D.; Ali, A.; Anda, G.; ...

2018-02-07

In this work, Wendelstein 7-X (W7-X) is the world’s largest superconducting nuclear fusion experiment of the optimized stellarator type. In the first Operation Phase (OP1.1) helium and hydrogen plasmas were studied in limiter configuration. The heating energy was limited to 4 MJ and the main purpose of that campaign was the integral commissioning of the machine and diagnostics, which was achieved very successfully. Already from the beginning a comprehensive set of diagnostics was available to study the plasma. On the path towards high-power, high-performance plasmas, W7-X will be stepwise upgraded from an inertially cooled (OP1.2, limited to 80 MJ) tomore » an actively cooled island divertor (OP2, 10 MW steady-state plasma operation). The machine is prepared for OP1.2 with 10 inertially cooled divertor units, and the experimental campaign has started recently.The paper describes a subset of diagnostics which will be available for OP1.2 to study the plasma edge, divertor and scrape-off layer physics including those already available for OP1.1, plus modifications, upgrades and new systems. In conclusion, the focus of this summary will be on technical and engineering aspects, like feasibility and assembly but also on reliability, thermal loads and shielding against magnetic fields.« less

Temperature of Heating and Cooling of Massive, Thin, and Wedge-Shaped Plates from Hard-to-Machine Steels During Their Grinding

NASA Astrophysics Data System (ADS)

Dement‧ev, V. B.; Ivanova, T. N.; Dolginov, A. M.

2017-01-01

Grinding of flat parts occurs by solid abrasive particles due to the physicomechanical process of deformation and to the action of a process liquid at high temperatures in a zone small in volume and difficult for observation. The rate of heating and cooling depends on the change in the intensity of the heat flux and in the velocity and time of action of the heat source. A study has been made of the regularities of the influence of each of these parameters on the depth and character of structural transformations during the grinding of flat parts from hard-to-machine steels. A procedure to calculate temperature in grinding massive, thin, and wedge-shaped parts has been developed with account taken of the geometric and thermophysical parameters of the tool and the treated part, and also of cutting regimes. The procedure can be used as a constituent part in developing a system for automatic design of the technological process of grinding of flat surfaces. A relationship between the temperature in the grinding zone and the regimes of treatment has been established which makes it possible to control the quality of the surface layer of massive, thin, and wedge-shaped plates from hard-to-machine steels. The rational boundaries of shift of cutting regimes have been determined.

Monitoring Temperature and Fan Speed Using Ganglia and Winbond Chips

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCaffrey, Cattie; /SLAC

2006-09-27

Effective monitoring is essential to keep a large group of machines, like the ones at Stanford Linear Accelerator Center (SLAC), up and running. SLAC currently uses Ganglia Monitoring System to observe about 2000 machines, analyzing metrics like CPU usage and I/O rate. However, metrics essential to machine hardware health, such as temperature and fan speed, are not being monitored. Many machines have a Winbond w83782d chip which monitors three temperatures, two of which come from dual CPUs, and returns the information when the sensor command is invoked. Ganglia also provides a feature, gmetric, that allows the users to monitor theirmore » own metrics and incorporate them into the monitoring system. The programming language Perl is chosen to implement a script that invokes the sensors command, extracts the temperature and fan speed information, and calls gmetric with the appropriate arguments. Two machines were used to test the script; the two CPUs on each machine run at about 65 Celsius, which is well within the operating temperature range (The maximum safe temperature range is 77-82 Celsius for the Pentium III processors being used). Installing the script on all machines with a Winbond w83782d chip allows the SLAC Scientific Computing and Computing Services group (SCCS) to better evaluate current cooling methods.« less

Evaluation of Workpiece Temperature during Drilling of GLARE Fiber Metal Laminates Using Infrared Techniques: Effect of Cutting Parameters, Fiber Orientation and Spray Mist Application.

PubMed

Giasin, Khaled; Ayvar-Soberanis, Sabino

2016-07-28

The rise in cutting temperatures during the machining process can influence the final quality of the machined part. The impact of cutting temperatures is more critical when machining composite-metal stacks and fiber metal laminates due to the stacking nature of those hybrids which subjects the composite to heat from direct contact with metallic part of the stack and the evacuated hot chips. In this paper, the workpiece surface temperature of two grades of fiber metal laminates commercially know as GLARE is investigated. An experimental study was carried out using thermocouples and infrared thermography to determine the emissivity of the upper, lower and side surfaces of GLARE laminates. In addition, infrared thermography was used to determine the maximum temperature of the bottom surface of machined holes during drilling GLARE under dry and minimum quantity lubrication (MQL) cooling conditions under different cutting parameters. The results showed that during the machining process, the workpiece surface temperature increased with the increase in feed rate and fiber orientation influenced the developed temperature in the laminate.

Evaluation of Workpiece Temperature during Drilling of GLARE Fiber Metal Laminates Using Infrared Techniques: Effect of Cutting Parameters, Fiber Orientation and Spray Mist Application

PubMed Central

Giasin, Khaled; Ayvar-Soberanis, Sabino

2016-01-01

The rise in cutting temperatures during the machining process can influence the final quality of the machined part. The impact of cutting temperatures is more critical when machining composite-metal stacks and fiber metal laminates due to the stacking nature of those hybrids which subjects the composite to heat from direct contact with metallic part of the stack and the evacuated hot chips. In this paper, the workpiece surface temperature of two grades of fiber metal laminates commercially know as GLARE is investigated. An experimental study was carried out using thermocouples and infrared thermography to determine the emissivity of the upper, lower and side surfaces of GLARE laminates. In addition, infrared thermography was used to determine the maximum temperature of the bottom surface of machined holes during drilling GLARE under dry and minimum quantity lubrication (MQL) cooling conditions under different cutting parameters. The results showed that during the machining process, the workpiece surface temperature increased with the increase in feed rate and fiber orientation influenced the developed temperature in the laminate. PMID:28773757

X-ray and optical emission-line filaments in the cooling flow cluster 2A 0335 + 096

NASA Technical Reports Server (NTRS)

Sarazin, Craig L.; O'Connell, Robert W.; Mcnamara, Brian R.

1992-01-01

We present a new high-resolution X-ray image of the 2A 0335 + 096 cluster of galaxies obtained with the High Resolution Imager (HRI) aboard the ROSAT satellite. The presence of dense gas having a very short cooling time in the central regions confirms its earlier identification as a cooling flow. The X-ray emission from the central regions of the cooling flow shows a great deal of filamentary structure. Using the crude spectral resolution of the HRI, we show that these filaments are the result of excess emission, rather than foreground X-ray absorption. Although there are uncertainties in the pointing, many of the X-ray features in the cooling flow region correspond to features in H-alpha optical line emission. This suggests that the optical emission line gas has resulted directly from the cooling of X-ray-emitting gas. The filament material cannot be in hydrostatic equilibrium, and it is likely that other forces such as rotation, turbulence, and magnetic fields influence the dynamical state of the gas.

Cooler Tile-Roofed Buildings with Near-Infrared-ReflectiveNon-white Coatings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Levinson, Ronnen; Akbari, Hashem; Reilly, Joeseph C.

Owners of homes with pitched roofs visible from ground leveloften prefer non-white roofing products for aesthetic considerations.Non-white, near-infrared-reflective architectural coatings can be appliedin-situ to pitched concrete or clay tile roofs to reduce tiletemperature, building heat gain, and cooling power demand, whilesimultaneously improving the roof s appearance. Scale model measurementsof building temperatures and heat-flux were combined with solar andcooling energy use data to estimate the effects of such cool roofcoatings in various California data. Under typical conditions e.g., 1 kWm-2 summer afternoon insolation, R-11 attic insulation, no radiantbarrier, and a 0.3 reduction in solar absorptance absolute reductions inroof surface temperature, atticmore » air temperature, and ceiling heat fluxare about 12 K, 6.2 K, and 3.7 W m-2, respectively. For a typical 1,500ft2 (139 m2) house with R-11 attic insulation and no radiant barrier,reducing roof absorptance by 0.3 yields whole-house peak power savings of230, 210, and 210 W in Fresno, San Bernardino, and San Diego,respectively. The corresponding absolute and fractional cooling energysavings are 92 kWh yr-1 (5 percent), 67 kWh yr-1 (6 percent), and 8 kWhyr-1 (1 percent), respectively. These savings are about half thosepreviously reported for houses with non-tile roofs. With theseassumptions, the statewide peak cooling power and annual cooling energyreductions would be 240 MW and 63 GWh yr-1, respectively. These energysavings would reduce annual emissions from California power plants by 35kilotonnes CO2, 11 tonnes NOx,and 0.86 tonnes SOx. The economic value ofcooling energy savings is well below the cost of coating a tile roof, butthe simple payback times for using cool pigments in a rooftile coatingare modest (5-7 years) in the hot climates of Fresno and SanBernardino.« less

Spectroscopic and laser cooling results on Yb3+-doped BaY2F8 single crystal

NASA Astrophysics Data System (ADS)

Bigotta, Stefano; Parisi, Daniela; Bonelli, Lucia; Toncelli, Alessandra; Tonelli, Mauro; Di Lieto, Alberto

2006-07-01

Anti-Stokes cooling has been observed in an Yb3+-doped BaY2F8 single crystal. Single crystals have been grown by the Czochralski technique. The absorption spectra and the emission properties have been measured at room temperature and at 10K. The energy positions of the Stark sublevels of the ground and the excited state manifolds have been determined and separated from the vibronic substructure. The intrinsic decay time of the F5/22 level has been measured taking care of avoiding the effect of multiple reabsorption processes. The theoretical and experimental cooling efficiencies of Yb:BaY2F8 are evaluated and compared with respect to those of the most frequently investigated materials for laser cooling. A temperature drop of almost 4K was measured by pumping the crystal with 3W of laser radiation at ˜1025nm in single pass configuration with a cooling efficiency of ˜3%.

Energy-Saving Melting and Revert Reduction Technology (E-SMARRT): Use of Laser Engineered Net Shaping for Rapid Manufacturing of Dies with Protective Coatings and Improved Thermal Management

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brevick, Jerald R.

2014-06-13

In the high pressure die casting process, molten metal is introduced into a die cavity at high pressure and velocity, enabling castings of thin wall section and complex geometry to be obtained. Traditional die materials have been hot work die steels, commonly H13. Manufacture of the dies involves machining the desired geometry from monolithic blocks of annealed tool steel, heat treating to desired hardness and toughness, and final machining, grinding and polishing. The die is fabricated with internal water cooling passages created by drilling. These materials and fabrication methods have been used for many years, however, there are limitations. Toolmore » steels have relatively low thermal conductivity, and as a result, it takes time to remove the heat from the tool steel via the drilled internal water cooling passages. Furthermore, the low thermal conductivity generates large thermal gradients at the die cavity surfaces, which ultimately leads to thermal fatigue cracking on the surfaces of the die steel. The high die surface temperatures also promote the metallurgical bonding of the aluminum casting alloy to the surface of the die steel (soldering). In terms of process efficiency, these tooling limitations reduce the number of die castings that can be made per unit time by increasing cycle time required for cooling, and increasing downtime and cost to replace tooling which has failed either by soldering or by thermal fatigue cracking (heat checking). The objective of this research was to evaluate the feasibility of designing, fabricating, and testing high pressure die casting tooling having properties equivalent to H13 on the surface in contact with molten casting alloy - for high temperature and high velocity molten metal erosion resistance – but with the ability to conduct heat rapidly to interior water cooling passages. A layered bimetallic tool design was selected, and the design evaluated for thermal and mechanical performance via finite element analysis. H13 was retained as the exterior layer of the tooling, while commercially pure copper was chosen for the interior structure of the tooling. The tooling was fabricated by traditional machining of the copper substrate, and H13 powder was deposited on the copper via the Laser Engineered Net Shape (LENSTM) process. The H13 deposition layer was then final machined by traditional methods. Two tooling components were designed and fabricated; a thermal fatigue test specimen, and a core for a commercial aluminum high pressure die casting tool. The bimetallic thermal fatigue specimen demonstrated promising performance during testing, and the test results were used to improve the design and LENS TM deposition methods for subsequent manufacture of the commercial core. Results of the thermal finite element analysis for the thermal fatigue test specimen indicate that it has the ability to lose heat to the internal water cooling passages, and to external spray cooling, significantly faster than a monolithic H13 thermal fatigue sample. The commercial core is currently in the final stages of fabrication, and will be evaluated in an actual production environment at Shiloh Die casting. In this research, the feasibility of designing and fabricating copper/H13 bimetallic die casting tooling via LENS TM processing, for the purpose of improving die casting process efficiency, is demonstrated.« less

Combination of Ultrasonic Vibration and Cryogenic Cooling for Cutting Performance Improvement of Inconel 718 Turning

NASA Astrophysics Data System (ADS)

Lin, S. Y.; Chung, C. T.; Cheng, Y. Y.

2011-01-01

The main objective of this study is to develop a thermo-elastic-plastic coupling model, based on a combination skill of ultrasonically assisted cutting and cryogenic cooling, under large deformation for Inconel 718 alloy machining process. The improvement extent on cutting performance and tool life promotion may be examined from this investigation. The critical value of the strain energy density of the workpiece will be utilized as the chip separation and the discontinuous chip segmentation criteria. The forced convection cooling and a hydrodynamic lubrication model will be considered and formulated in the model. Finite element method will be applied to create a complete numerical solution for this ultrasonic vibration cutting model. During the analysis, the cutting tool is incrementally advanced forward with superimposed ultrasonic vibration in a back and forth step-by-step manner, from an incipient stage of tool-workpiece engagement to a steady state of chip formation, a whole simulation of orthogonal cutting process under plane strain deformation is thus undertaken. High shear strength induces a fluctuation phenomenon of shear angle, high shear strain rate, variation of chip types and chip morphology, tool-chip contact length variation, the temperature distributions within the workpiece, chip and tool, periodic fluctuation in cutting forces can be determined from the developed model. A complete comparison of machining characteristics between some different combinations of ultrasonically assisted cutting and cryogenic cooling with conventional cutting operation can be acquired. Finally, the high-speed turning experiment for Inconel 718 alloy will be taken in the laboratory to validate the accuracy of the model, and the progressive flank wear, crater wear, notching and chipping of the tool edge can also be measured in the experiments.

Machine Phase Fullerene Nanotechnology: 1996

NASA Technical Reports Server (NTRS)

Globus, Al; Chancellor, Marisa K. (Technical Monitor)

1997-01-01

NASA has used exotic materials for spacecraft and experimental aircraft to good effect for many decades. In spite of many advances, transportation to space still costs about $10,000 per pound. Drexler has proposed a hypothetical nanotechnology based on diamond and investigated the properties of such molecular systems. These studies and others suggest enormous potential for aerospace systems. Unfortunately, methods to realize diamonoid nanotechnology are at best highly speculative. Recent computational efforts at NASA Ames Research Center and computation and experiment elsewhere suggest that a nanotechnology of machine phase functionalized fullerenes may be synthetically relatively accessible and of great aerospace interest. Machine phase materials are (hypothetical) materials consisting entirely or in large part of microscopic machines. In a sense, most living matter fits this definition. To begin investigation of fullerene nanotechnology, we used molecular dynamics to study the properties of carbon nanotube based gears and gear/shaft configurations. Experiments on C60 and quantum calculations suggest that benzyne may react with carbon nanotubes to form gear teeth. Han has computationally demonstrated that molecular gears fashioned from (14,0) single-walled carbon nanotubes and benzyne teeth should operate well at 50-100 gigahertz. Results suggest that rotation can be converted to rotating or linear motion, and linear motion may be converted into rotation. Preliminary results suggest that these mechanical systems can be cooled by a helium atmosphere. Furthermore, Deepak has successfully simulated using helical electric fields generated by a laser to power fullerene gears once a positive and negative charge have been added to form a dipole. Even with mechanical motion, cooling, and power; creating a viable nanotechnology requires support structures, computer control, a system architecture, a variety of components, and some approach to manufacture. Additional information is contained within the original extended abstract.

Micromachined Active Magnetic Regenerator for Low-Temperature Magnetic Coolers

NASA Technical Reports Server (NTRS)

Chen, Weibo; Jaeger, Michael D.

2013-01-01

A design of an Active Magnetic Regenerative Refrigeration (AMRR) system has been developed for space applications. It uses an innovative 3He cryogenic circulator to provide continuous remote/distributed cooling at temperatures in the range of 2 K with a heat sink at about 15 K. A critical component technology for this cooling system is a highly efficient active magnetic regenerator, which is a regenerative heat exchanger with its matrix material made of magnetic refrigerant gadolinium gallium garnet (GGG). Creare Inc. is developing a microchannel GGG regenerator with an anisotropic structured bed for high system thermal efficiency. The regenerator core consists of a stack of thin, single-crystal GGG disks alternating with thin polymer insulating layers. The insulating layers help minimize the axial conduction heat leak, since GGG has a very high thermal conductivity in the regenerator s operating temperature range. The GGG disks contain micro channels with width near 100 micrometers, which enhance the heat transfer between the circulating flow and the refrigerant bed. The unique flow configuration of the GGG plates ensures a uniform flow distribution across the plates. The main fabrication challenges for the regenerator are the machining of high-aspect-ratio microchannels in fragile, single-crystal GGG disks and fabrication and assembly of the GGG insulation layers. Feasibility demonstrations to date include use of an ultrashort- pulse laser to machine microchannels without producing unacceptable microcracking or deposition of recast material, as shown in the figure, and attachment of a thin insulation layer to a GGG disk without obstructing the flow paths. At the time of this reporting, efforts were focused on improving the laser machining process to increase machining speed and further reduce microcracking.

Lunar stone saw

NASA Technical Reports Server (NTRS)

Clark, Tom; Croker, Todd; Hines, Ken; Knight, Mike; Walton, Todd

1988-01-01

This project addresses the problem of cutting lunar stones into blocks to be used to construct shelters to protect personnel and equipment from harmful solar radiation. This plant will manufacture 6 in x 1 ft x 2 ft blocks and will be located near the south pole to allow it to be in the shade at all times. This design uses a computer controlled robot, a boulder handler that uses hydraulics for movement, a computer system that used 3-D vision to determine the size of boulders, a polycrystalline diamond tipped saw blade that utilizes radiation for cooling, and a solar tower to collect solar energy. Only two electric motors are used in this plant because of the heavy weight of electric motors and the problem of cooling them. These two motors will be cooled by thermoelectric cooling. All other motors and actuators are to be hydraulic. The architectural design for the building as well as the conceptual design of the machines for cutting the blocks are described.

Fabrication of gas turbine water-cooled composite nozzle and bucket hardware employing plasma spray process

DOEpatents

Schilke, Peter W.; Muth, Myron C.; Schilling, William F.; Rairden, III, John R.

1983-01-01

In the method for fabrication of water-cooled composite nozzle and bucket hardware for high temperature gas turbines, a high thermal conductivity copper alloy is applied, employing a high velocity/low pressure (HV/LP) plasma arc spraying process, to an assembly comprising a structural framework of copper alloy or a nickel-based super alloy, or combination of the two, and overlying cooling tubes. The copper alloy is plamsa sprayed to a coating thickness sufficient to completely cover the cooling tubes, and to allow for machining back of the copper alloy to create a smooth surface having a thickness of from 0.010 inch (0.254 mm) to 0.150 inch (3.18 mm) or more. The layer of copper applied by the plasma spraying has no continuous porosity, and advantageously may readily be employed to sustain a pressure differential during hot isostatic pressing (HIP) bonding of the overall structure to enhance bonding by solid state diffusion between the component parts of the structure.

Weldability, machinability and surfacing of commercial duplex stainless steel AISI2205 for marine applications - A recent review.

PubMed

Vinoth Jebaraj, A; Ajaykumar, L; Deepak, C R; Aditya, K V V

2017-05-01

In the present review, attempts have been made to analyze the metallurgical, mechanical, and corrosion properties of commercial marine alloy duplex stainless steel AISI 2205 with special reference to its weldability, machinability, and surfacing. In the first part, effects of various fusion and solid-state welding processes on joining DSS 2205 with similar and dissimilar metals are addressed. Microstructural changes during the weld cooling cycle such as austenite reformation, partitioning of alloying elements, HAZ transformations, and the intermetallic precipitations are analyzed and compared with the different welding techniques. In the second part, machinability of DSS 2205 is compared with the commercial ASS grades in order to justify the quality of machining. In the third part, the importance of surface quality in a marine exposure is emphasized and the enhancement of surface properties through peening techniques is highlighted. The research gaps and inferences highlighted in this review will be more useful for the fabrications involved in the marine applications.

Prediction based proactive thermal virtual machine scheduling in green clouds.

PubMed

Kinger, Supriya; Kumar, Rajesh; Sharma, Anju

2014-01-01

Cloud computing has rapidly emerged as a widely accepted computing paradigm, but the research on Cloud computing is still at an early stage. Cloud computing provides many advanced features but it still has some shortcomings such as relatively high operating cost and environmental hazards like increasing carbon footprints. These hazards can be reduced up to some extent by efficient scheduling of Cloud resources. Working temperature on which a machine is currently running can be taken as a criterion for Virtual Machine (VM) scheduling. This paper proposes a new proactive technique that considers current and maximum threshold temperature of Server Machines (SMs) before making scheduling decisions with the help of a temperature predictor, so that maximum temperature is never reached. Different workload scenarios have been taken into consideration. The results obtained show that the proposed system is better than existing systems of VM scheduling, which does not consider current temperature of nodes before making scheduling decisions. Thus, a reduction in need of cooling systems for a Cloud environment has been obtained and validated.

Damage of actively cooled plasma facing components of magnetic confinement controlled fusion machines

NASA Astrophysics Data System (ADS)

Chevet, G.; Schlosser, J.; Martin, E.; Herb, V.; Camus, G.

2009-03-01

Plasma facing components (PFCs) of magnetic fusion machines have high manufactured residual stresses and have to withstand important stress ranges during operation. These actively cooled PFCs have a carbon fibre composite (CFC) armour and a copper alloy heat sink. Cracks mainly appear in the CFC near the composite/copper interface. In order to analyse damage mechanisms, it is important to well simulate the damage mechanisms both of the CFC and the CFC/Cu interface. This study focuses on the mechanical behaviour of the N11 material for which the scalar ONERA damage model was used. The damage parameters of this model were identified by similarity to a neighbour material, which was extensively analysed, according to the few characterization test results available for the N11. The finite elements calculations predict a high level of damage of the CFC at the interface zone explaining the encountered difficulties in the PFCs fabrication. These results suggest that the damage state of the CFC cells is correlated with a conductivity decrease to explain the temperature increase of the armour surface under fatigue heat load.

Contamination in Orbit of GOES-8

NASA Technical Reports Server (NTRS)

Sanders, Jack T.

2002-01-01

The GOES-8 satellite has lost some of its ability to dissipate heat over time. This is shown by the temperature increases over time of spacecraft and instrument components that are cooled with optical solar reflector (OSR) radiators. Contamination has a significant, well-documented effect on the solar absorptance (a(sub s)) of OSRs. This document attempts to discern how much molecular contamination has collected on the Imager and Sounder radiant coolers by analyzing the increase in temperature of the vacuum cooler housing. In the first part, temperature change is transformed into solar absorptance units by a method devised by ITT. The second part transfomis the solar absorptance gain into a molecular film thickness.

Candidate chemical systems for air cooled solar powered, absorption air conditioner design. Part I. Organic absorbent systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biermann, W. J.

1978-01-01

All the available experimental evidence suggests that the optimum ''organic'' absorbent/refrigerant combination would be a methane derivative with a single hydrogen atom with chlorine and fluorine atoms in the other sites, as refrigerant. This would be hydrogen bonded to an absorbent molecule containing the group =NC/sup -/O, with the substituent groups being such that no steric hindrance took place. Cycle analyses showed that the ratio of internal heat transfer to cooling would be large, probably impractically so in view of the high coefficient of performance needed for solar driven cooling and the additional handicap of heat rejection to the atmosphere.more » A more promising approach would be to reduce the internal heat transfer per unit of space cooling by selecting a refrigerant with a high latent heat of vaporization and selecting an absorbent with suitable properties.« less

Transient Heat Transfer in a Semitransparent Radiating Layer with Boundary Convection and Surface Reflections

NASA Technical Reports Server (NTRS)

Siegel, Robert

1996-01-01

Surface convection and refractive index are examined during transient radiative heating or cooling of a grey semitransparent layer with internal absorption, emission and conduction. Each side of the layer is exposed to hot or cold radiative surroundings, while each boundary is heated or cooled by convection. Emission within the layer and internal reflections depend on the layer refractive index. The reflected energy and heat conduction distribute energy across the layer and partially equalize the transient temperature distributions. Solutions are given to demonstrate the effect of radiative heating for layers with various optical thicknesses, the behavior of the layer heated by radiation on one side and convectively cooled on the other, and a layer heated by convection while being cooled by radiation. The numerical method is an implicit finite difference procedure with non-uniform space and time increments. The basic method developed in earlier work is expanded to include external convection and incident radiation.

Solar cooling system performance, Frenchman's Reef Hotel, Virgin Islands

NASA Astrophysics Data System (ADS)

Harber, H.

1981-09-01

The operational and thermal performance of a variety of solar systems are described. The Solar Cooling System was installed in a hotel at St. Thomas, U. S. Virgin Islands. The system consists of the evacuated glass tube collectors, two 2500 gallon tanks, pumps, computerized controller, a large solar optimized industrial sized lithium bromide absorption chiller, and associated plumbing. Solar heated water is pumped through the system to the designed public areas such as lobby, lounges, restaurant and hallways. Auxiliary heat is provided by steam and a heat exchanger to supplement the solar heat.

On the possibility of laser cooling of Cr3+ ions doped crystals

NASA Astrophysics Data System (ADS)

Feofilov, S. P.; Kulinkin, A. B.

2018-01-01

The fluorescence of Cr3+ ions doped insulating crystals was studied under the excitation in the long-wavelength tail of the absorption spectrum ("laser cooling regime"). The 4T2 - 4A2 and 2E - 4A2 fluorescence spectra with a dominant anti-Stokes component were observed. Though no optical refrigeration was detected in the presented experiments, the spectroscopic results suggest that electron-phonon bands of Cr3+ ions are of interest for further investigations from the point of view of achieving optical refrigeration.

Solar cooling system performance, Frenchman's Reef Hotel, Virgin Islands

NASA Technical Reports Server (NTRS)

Harber, H.

1981-01-01

The operational and thermal performance of a variety of solar systems are described. The Solar Cooling System was installed in a hotel at St. Thomas, U. S. Virgin Islands. The system consists of the evacuated glass tube collectors, two 2500 gallon tanks, pumps, computerized controller, a large solar optimized industrial sized lithium bromide absorption chiller, and associated plumbing. Solar heated water is pumped through the system to the designed public areas such as lobby, lounges, restaurant and hallways. Auxiliary heat is provided by steam and a heat exchanger to supplement the solar heat.

Phase I, open-cycle absorption solar cooling. Part IV. Executive summary analysis and resolution of critical issues and recommendations for Phase II. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wood, B.D.

The objective of this project is to advance lower cost solar cooling technology with the feasibility analysis, design and evaluation of proof-of-concept open cycle solar cooling concepts. The work is divided into three phases, with planned completion of each phase before proceeding with the following phase: Phase I - performance/economic/environmental related analysis and exploratory studies; Phase II - design and construction of an experimental system, including evaluative testing; Phase III - extended system testing during operation and engineering modifications as required. For Phase I, analysis and resolution of critical issues were completed with the objective of developing design specifications formore » an improved prototype OCA system.« less

Heavy Elements and Cool Stars

NASA Technical Reports Server (NTRS)

Wahlgren, Glenn M.; Carpenter, Kenneth G.; Norris, Ryan P.

2008-01-01

We report on progress in the analysis of high-resolution near-IR spectra of alpha Orionis (M2 Iab) and other cool, luminous stars. Using synthetic spectrum techniques, we search for atomic absorption lines in the stellar spectra and evaluate the available line parameter data for use in our abundance analyses. Our study concentrates on the post iron-group elements copper through zirconium as a means of investigating the slow neutron-capture process of nucleosynthesis in massive stars and the mechanisms that transport recently processed material up into the photospheric region. We discuss problems with the atomic data and model atmospheres that need to be addressed before theoretically derived elemental abundances from pre-supernova nucleosynthesis calculations can be tested by comparison with abundances determined from observations of cool, massive stars.

Thermoelectric Energy Conversion: Future Directions and Technology Development Needs

NASA Technical Reports Server (NTRS)

Fleurial, Jean-Pierre

2007-01-01

This viewgraph presentation reviews the process of thermoelectric energy conversion along with key technology needs and challenges. The topics include: 1) The Case for Thermoelectrics; 2) Advances in Thermoelectrics: Investment Needed; 3) Current U.S. Investment (FY07); 4) Increasing Thermoelectric Materials Conversion Efficiency Key Science Needs and Challenges; 5) Developing Advanced TE Components & Systems Key Technology Needs and Challenges; 6) Thermoelectrics; 7) 200W Class Lightweight Portable Thermoelectric Generator; 8) Hybrid Absorption Cooling/TE Power Cogeneration System; 9) Major Opportunities in Energy Industry; 10) Automobile Waste Heat Recovery; 11) Thermoelectrics at JPL; 12) Recent Advances at JPL in Thermoelectric Converter Component Technologies; 13) Thermoelectrics Background on Power Generation and Cooling Operational Modes; 14) Thermoelectric Power Generation; and 15) Thermoelectric Cooling.

Automotive absorption air conditioner utilizing solar and motor waste heat

NASA Technical Reports Server (NTRS)

Popinski, Z. (Inventor)

1981-01-01

In combination with the ground vehicles powered by a waste heat generating electric motor, a cooling system including a generator for driving off refrigerant vapor from a strong refrigerant absorbant solution is described. A solar collector, an air-cooled condenser connected with the generator for converting the refrigerant vapor to its liquid state, an air cooled evaporator connected with the condenser for returning the liquid refrigerant to its vapor state, and an absorber is connected to the generator and to the evaporator for dissolving the refrigerant vapor in the weak refrigerant absorbant solution, for providing a strong refrigerant solution. A pump is used to establish a pressurized flow of strong refrigerant absorbant solution from the absorber through the electric motor, and to the collector.

Absorption of language concepts in the machine mind

NASA Astrophysics Data System (ADS)

Kollár, Ján

2016-06-01

In our approach, the machine mind is the applicative dynamic system represented by its algorithmically evolvable internal language. By other words, the mind and the language of mind are synonyms. Coming out from Shaumyan's semiotic theory of languages, we present the representation of language concepts in the machine mind as a result of our experiment, to show non-redundancy of the language of mind. To provide useful restriction for further research, we also introduce the hypothesis of semantic saturation in Computer-Computer communication, which indicates that a set of machines is not self-evolvable. The goal of our research is to increase the abstraction of Human-Computer and Computer-Computer communication. If we want humans and machines comunicate as a parent with the child, using different symbols and media, we must find the language of mind commonly usable by both machines and humans. In our opinion, there exist a kind of calm language of thinking, which we try to propose for machines in this paper. We separate the layers of a machine mind, we present the structure of the evolved mind and we discuss the selected properties. We are concentrating on the representation of symbolized concepts in the mind, that are languages, not just grammars, since they have meaning.

The extent of chemically enriched gas around star-forming dwarf galaxies

NASA Astrophysics Data System (ADS)

Johnson, Sean

2018-01-01

Supernovae driven winds are often invoked to remove chemically enriched gas from galaxies to match the low metallicities of dwarf galaxies. In such shallow potential wells, outflows may produce massive amounts of enriched halo gas (circum-galactic medium or CGM) and pollute the intergalactic medium (IGM). I will present a survey of the CGM and IGM around 18 star-forming field dwarf galaxies with stellar masses of log M*/M⊙ ≈ 8 ‑ 9 at z ≈ 0.2. Eight of these have CGM probed by quasar absorption spectra at projected distances, d, less than the host virial radius, Rh. Ten are probed at d/Rh = 1 ‑ 3 to study the surrounding IGM. The absorption measurements include neutral hydrogen (H I), the dominant silicon ions for diffuse cool gas (T ∼ 104 K; Si II, Si III, and Si IV), more highly ionized carbon (C IV), and highly ionized oxygen (O VI). The metal absorption from the CGM of the dwarf galaxies is less common and ≈ 4× weaker compared to massive star-forming galaxies though O VI absorption is still common. None of the dwarfs probed at d/Rh = 1 ‑ 3 have definitive metal-line detections. Combining the available silicon ions, we estimate that the cool CGM accounts for only 2 ‑ 6% of the expected silicon budget. CGM absorption from O VI can account for ≈ 8% of the expected oxygen budget. As O VI traces an ion with expected equilibrium ion fractions of 0.2, this highly ionized phase of the CGM may represent a significant metal reservoir even for dwarf galaxies not expected to maintain gravitationally shock heated hot halos.

Lubricating system for thermal medium delivery parts in a gas turbine

DOEpatents

Mashey, Thomas Charles

2002-01-01

Cooling steam delivery tubes extend axially along the outer rim of a gas turbine rotor for supplying cooling steam to and returning spent cooling steam from the turbine buckets. Because of the high friction forces at the interface of the tubes and supporting elements due to rotor rotation, a low coefficient of friction coating is provided at the interface of the tubes and support elements. On each surface, a first coating of a cobalt-based alloy is sprayed onto the surface at high temperature. A portion of the first coating is machined off to provide a smooth, hard surface. A second ceramic-based solid film lubricant is sprayed onto the first coating. By reducing the resistance to axial displacement of the tubes relative to the supporting elements due to thermal expansion, the service life of the tubes is substantially extended.

Flexible composite material with phase change thermal storage

NASA Technical Reports Server (NTRS)

Buckley, Theresa M. (Inventor)

2001-01-01

A highly flexible composite material having a flexible matrix containing a phase change thermal storage material. The composite material can be made to heat or cool the body or to act as a thermal buffer to protect the wearer from changing environmental conditions. The composite may also include an external thermal insulation layer and/or an internal thermal control layer to regulate the rate of heat exchange between the composite and the skin of the wearer. Other embodiments of the PCM composite also provide 1) a path for evaporation or direct absorption of perspiration from the skin of the wearer for improved comfort and thermal control, 2) heat conductive pathways within the material for thermal equalization, 3) surface treatments for improved absorption or rejection of heat by the material, and 4) means for quickly regenerating the thermal storage capacity for reuse of the material. Applications of the composite materials are also described which take advantage of the composite's thermal characteristics. The examples described include a diver's wet suit, ski boot liners, thermal socks, ,gloves and a face mask for cold weather activities, and a metabolic heating or cooling blanket useful for treating hypothermia or fever patients in a medical setting and therapeutic heating or cooling orthopedic joint supports.

Flexible composite material with phase change thermal storage

NASA Technical Reports Server (NTRS)

Buckley, Theresa M. (Inventor)

1999-01-01

A highly flexible composite material having a flexible matrix containing a phase change thermal storage material. The composite material can be made to heat or cool the body or to act as a thermal buffer to protect the wearer from changing environmental conditions. The composite may also include an external thermal insulation layer and/or an internal thermal control layer to regulate the rate of heat exchange between the composite and the skin of the wearer. Other embodiments of the PCM composite also provide 1) a path for evaporation or direct absorption of perspiration from the skin of the wearer for improved comfort and thermal control, 2) heat conductive pathways within the material for thermal equalization, 3) surface treatments for improved absorption or rejection of heat by the material, and 4) means for quickly regenerating the thermal storage capacity for reuse of the material. Applications of the composite materials are also described which take advantage of the composite's thermal characteristics. The examples described include a diver's wet suit, ski boot liners, thermal socks, gloves and a face mask for cold weather activities, and a metabolic heating or cooling blanket useful for treating hypothermia or fever patients in a medical setting and therapeutic heating or cooling orthopedic joint supports.

A study of cooling flows in poor clusters of galaxies

NASA Technical Reports Server (NTRS)

Kriss, Gerard A.; Dillingham, Stephen

1995-01-01

We observed three poor clusters with central dominant galaxies (AWM 4, MKW 4, and MKW 3's) using the Position Sensitive Proportional Counter on the ROSAT X-ray satellite. The images reveal smooth, symmetrical X-ray emission filling the cluster with a sharp peak on each central galaxy. The cluster surface brightness profiles can be decomposed using superposed King models for the central galaxy and the intracluster medium. The King model parameters for the cluster portions are consistent with previous observations of these clusters. The newly measured King model parameters for the central galaxies are typical of the X-ray surface brightness distributions of isolated elliptical galaxies. Spatially resolved temperature measurements in annular rings throughout the clusters show a nearly isothermal profile. Temperatures are consistent with previously measured values, but are much better determined. There is no significant drop in temperature noted in the innermost bins where cooling flows are likely to be present, nor is any excess absorption by cold gas required. All cold gas columns are consistent with galactic foreground absorption. We derive mass profiles for the clusters assuming both isothermal temperature profiles and cooling flow models with constant mass flow rates. Our results are consistent with previous Einstein IPC observations by Kriss, Cioffi, & Canizares, but extend the mass profiles out to 1 Mpc in these poor clusters.

Direct Correlation of Excitonics with Efficiency in a Core-Shell Quantum Dot Solar Cell.

PubMed

Dana, Jayanta; Maiti, Sourav; Tripathi, Vaidehi S; Ghosh, Hirendra N

2018-02-16

Shell thickness dependent band-gap engineering of quasi type II core-shell material with higher carrier cooling time, lower interfacial defect states, and longer charge carrier recombination time can be a promising candidate for both photocatalysis and solar cell. In the present investigation, colloidal CdSe@CdS core-shells with different shell thickness (2, 4 and 6 monolayer CdS) were synthesized through hot injection method and have been characterized by high resolution transmission electron microscope (HRTEM) followed by steady state absorption and luminescence techniques. Ultrafast transient absorption (TA) studies suggest longer carrier cooling, lower interfacial surface states, and slower carrier recombination time in CdSe@CdS core-shell with increasing shell thickness. By TA spectroscopy, the role of CdS shell in power conversion efficiency (PCE) has been explained in detail. The measured PCE was found to initially increase and then decrease with increasing shell thickness. Shell thickness has been optimized to maximize the efficiency after correlating the shell controlled carrier cooling and recombination with PCE values and a maximum PCE of 3.88 % was obtained with 4 monolayers of CdS shell, which is found to be 57 % higher than compared to bare CdSe QDs. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

National Synchrotron Light Source annual report 1991. Volume 1, October 1, 1990--September 30, 1991

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hulbert, S.L.; Lazarz, N.M.

1992-04-01

This report discusses the following research conducted at NSLS: atomic and molecular science; energy dispersive diffraction; lithography, microscopy and tomography; nuclear physics; UV photoemission and surface science; x-ray absorption spectroscopy; x-ray scattering and crystallography; x-ray topography; workshop on surface structure; workshop on electronic and chemical phenomena at surfaces; workshop on imaging; UV FEL machine reviews; VUV machine operations; VUV beamline operations; VUV storage ring parameters; x-ray machine operations; x-ray beamline operations; x-ray storage ring parameters; superconducting x-ray lithography source; SXLS storage ring parameters; the accelerator test facility; proposed UV-FEL user facility at the NSLS; global orbit feedback systems; and NSLSmore » computer system.« less

MAGIICAT III. Interpreting Self-similarity of the Circumgalactic Medium with Virial Mass Using Mg II Absorption

NASA Astrophysics Data System (ADS)

Churchill, Christopher W.; Trujillo-Gomez, Sebastian; Nielsen, Nikole M.; Kacprzak, Glenn G.

2013-12-01

In Churchill et al., we used halo abundance matching applied to 182 galaxies in the Mg II Absorber-Galaxy Catalog (MAGIICAT) and showed that the mean Mg II λ2796 equivalent width follows a tight inverse-square power law, Wr (2796)vprop(D/R vir)-2, with projected location relative to the galaxy virial radius and that the Mg II absorption covering fraction is effectively invariant with galaxy virial mass, M h, over the range 10.7 <= log M h/M ⊙ <= 13.9. In this work, we explore multivariate relationships between Wr (2796), virial mass, impact parameter, virial radius, and the theoretical cooling radius that further elucidate self-similarity in the cool/warm (T = 104-104.5 K) circumgalactic medium (CGM) with virial mass. We show that virial mass determines the extent and strength of the Mg II absorbing gas such that the mean Wr (2796) increases with virial mass at fixed distance while decreasing with galactocentric distance for fixed virial mass. The majority of the absorbing gas resides within D ~= 0.3 R vir, independent of both virial mass and minimum absorption threshold; inside this region, and perhaps also in the region 0.3 < D/R vir <= 1, the mean Wr (2796) is independent of virial mass. Contrary to absorber-galaxy cross-correlation studies, we show there is no anti-correlation between Wr (2796) and virial mass. We discuss how simulations and theory constrained by observations support self-similarity of the cool/warm CGM via the physics governing star formation, gas-phase metal enrichment, recycling efficiency of galactic scale winds, filament and merger accretion, and overdensity of local environment as a function of virial mass.

Crystal-field effects in fluoride crystals for optical refrigeration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hehlen, Markus P

2010-01-01

The field of optical refrigeration of rare-earth-doped solids has recently seen an important breakthrough. The cooling of a YLiF{sub 4} (YLF) crystal doped with 5 mol% Yb3+ to 155 K by Seletskiy et al [NPhot] has surpassed the lowest temperatures ({approx}170 K for {approx}100 mW cooling capacity) that are practical with commercial multi-stage thermoelectric coolers (TEC) [Glaister]. This record performance has advanced laser cooling into an application relevant regime and has put first practical optical cryocoolers within reach. The result is also relevant from a material perspective since for the first time, an Yb3+-doped crystal has outperformed an Yb3+-doped glass.more » The record temperature of 208 K was held by the Yb3+-doped fluorozirconate glass ZBLAN. Advanced purification and glass fabrication methods currently under development are expected to also advance ZBLAN:Yb3+ to sub-TEC temperatures. However, recent achievements with YLF:Yb3+ illustrate that crystalline materials may have two potentially game-changing advantajes over glassy materials. First, the crystalline environment reduces the inhomogeneous broadening of the Yb3+ electronic transitions as compared to a glassy matrix. The respective sharpening of the crystal-field transitions increases the peak absorption cross section at the laser excitation wavelength and allows for more efficient pumping of the Yb3+ ions, particularly at low temperatures. Second, many detrimental impurities present in the starting materials tend to be excluded from the crystal during its slow growth process, in contrast to a glass where all impurities present in the starting materials are included in the glass when it is formed by temperature quenching a melt. The ultra high purity required for laser cooling materials [PRB] therefore may be easier to realize in crystals than in glasses. Laser cooling occurs by laser excitation of a rare-earth ion followed by anti-Stokes luminescence. Each such laser-cooling cycle extracts thermal energy from the solid and carries it away as high-entropy light, thereby cooling the material. In the ideal case, the respective laser-cooling power is given by the pump wavelength ({lambda}{sub p}), the mean fluorescence wavelength ({bar {lambda}}{sub L}), and the absorption coefficient (a{sub r}) of the pumped transition. These quantities are solely determined by crystal field interactions. On one hand, a large crystal-field splitting offers a favorably large difference of {lambda}{sub p} - {bar {lambda}}{sub L} and thus a high cooling efficiency {eta}{sub cool} = ({lambda}{sub p} - {bar {lambda}}{sub L})/{bar {lambda}}{sub L}. On the other hand, a small crystal-field splitting offers a high thermal population (n{sub i}) of the initial state of the pumped transition, giving a high pump absorption coefficient and thus high laser cooling power, particularly at low temperatures. A quantitative description of crystal-field interactions is therefore critical to the understanding and optimization of optical refrigeration. In the case of Yb3+ as the laser cooling ion, however, development of a crystal-field model is met with substantial difficulties. First, Yb3+ has only two 4/multiplets, {sup 2}F{sub 7/2} and {sup 2}F{sub 5/2}, which lead to at most 7 crystal-field levels. This makes it difficult, and in some cases impossible, to evaluate the crystal-field Hamiltonian, which has at least 4 parameters for any Yb3+ point symmety lower than cubic. Second, {sup 2}F{sub 7/2}{leftrightarrow}{sup 2}F{sub 5/2} transitions exhibit an exceptionally strong electron-phonon coupling compared to 4f transitions of other rare earths. This makes it difficult to distinguish electronic from vibronic transitions in the absorption and luminescence spectra and to reliably identify the crystal-field levels. Yb3+ crystal-field splittings reported in the literature should thus generally be viewed with caution. This paper explores the effects of crystal-field interactions on the laser cooling performance of Yb3+-doped fluoride crystals. It is shown that the total crystal-field splitting of the {sup 2}F{sub 7/2} and {sup 2}F{sub 5/2} multiplets of Yb3+ can be estimated from crystal-field splittings of other rare-earth-doped fluoride crystals. This approach takes advantage of an extensive body of experimental work from which Yb3+ doped fluoride crystals with favorable laser cooling properties might be identified. Section 2 reviews the crystal-field splitting of the 4f electronic states and introduces the crystal-field strength as a means to predict the total crystal-field splitting of the {sup 2}F{sub 7/2} and {sup 2}F{sub 5/2} multiplets. Section 3 illustrates the effect of the total {sup 2}F{sub 7/2} crystal field splitting on the laser cooling power. Finally, Section 4 compiles literature data on crystal-field splittings in fluoride crystals from which the {sup 2}F{sub 7/2} splitting is predicted.« less

Hermetic compressor and block expansion valve in refrigeration performance

NASA Astrophysics Data System (ADS)

Santoso, Budi; Susilo, Didik Djoko; Tjahjana, D. D. D. P.

2016-03-01

Vehicle cabin in tropical countries requires the cooling during the day for comfort of passengers. Air conditioning machine is commonly driven by an internal combustion engine having a great power, which the conventional compressor is connected to crank shaft. The stage of research done is driving the hermetic compressor with an electric motor, and using block expansion valve. The HFC-134a was used as refrigerant working. The primary parameters observed during the experiment are pressure, temperature, and power consumption for different cooling capacities. The results show that the highest coefficient of performance (COP) and the electric power of system are 6.3 and 638 Watt, respectively.

Design of a Film Cooling Experiment for Rocket Engines

DTIC Science & Technology

2010-03-01

concentrations inside the UCC (22)............................................................ 25 Figure 7: PIV data in the UCC (23...64 Figure 38: UCC /FCR igniter ............................................................................................. 65 Figure 39: Ethylene...TDLAS Tunable Diode Laser Absorption Spectroscopy UCC Ultra Compact Combustor μm micrometers VI Virtual Instrument Xe Xenon ZnSe

The integrated radio continuum spectrum of M33 - Evidence for free-free absorption by cool ionized gas

NASA Technical Reports Server (NTRS)

Israel, F. P.; Mahoney, M. J.; Howarth, N.

1992-01-01

We present measurements of the integrated radio continuum flux density of M33 at frequencies between 22 and 610 MHz and discuss the radio continuum spectrum of M33 between 22 MHz and 10 GHz. This spectrum has a turnover between 500 and 900 MHz, depending on the steepness of the high frequency radio spectrum of M33. Below 500 MHz the spectrum is relatively flat. We discuss possible mechanisms to explain this spectral shape and consider efficient free-free absorption of nonthermal emission by a cool (not greater than 1000 K) ionized gas to be a very likely possibility. The surface filling factor of both the nonthermal and the thermal material appears to be small (of order 0.001), which could be explained by magnetic field/density fluctuations in the M 33 interstellar medium. We briefly speculate on the possible presence of a nuclear radio source with a steep spectrum.

Copernicus observations of Betelgeuse and Antares

NASA Technical Reports Server (NTRS)

Bernat, A. P.; Lambert, D. L.

1976-01-01

The Mg II h and k lines were observed strongly in emission by Copernicus scans of the M supergiants alpha Ori and alpha Sco. The striking symmetry in the k line as contrasted with the symmetric h line, as observed previously was confirmed. Estimates of absolute chromospheric fluxes were obtained. Measured values for the widths of the h and k lines do not follow a Wilson-Bappu relationship. Upper limits determined for other chromospheric lines of alpha Ori tend to exclude the existence of extensive and/or hot regions surrounding this supergiant. Observed weakening by fluorescence of the Fe L 4307 A line is good evidence that the Mn I and Fe I resonance transitions overlying the Mg II k-line profile are responsible for the strong asymmetry of this line in the two stars. However, quantitative study shows that the absorption provided by the cool circumstellar shells is insufficient to provide the observed asymmetry. Additional absorption may be provided by a cool turbulent region at the top of the chromosphere.

Room-Temperature Coherent Optical Phonon in 2D Electronic Spectra of CH 3NH 3PbI 3 Perovskite as a Possible Cooling Bottleneck

DOE Office of Scientific and Technical Information (OSTI.GOV)

Monahan, Daniele M.; Guo, Liang; Lin, Jia

2017-06-29

A hot phonon bottleneck may be responsible for slow hot carrier cooling in methylammonium lead iodide hybrid perovskite, creating the potential for more efficient hot carrier photovoltaics. In room-temperature 2D electronic spectra near the band edge, we observe in this paper amplitude oscillations due to a remarkably long lived 0.9 THz coherent phonon population at room temperature. This phonon (or set of phonons) is assigned to angular distortions of the Pb–I lattice, not coupled to cation rotations. The strong coupling between the electronic transition and the 0.9 THz mode(s), together with relative isolation from other phonon modes, makes it likelymore » to cause a phonon bottleneck. Finally, the pump frequency resolution of the 2D spectra also enables independent observation of photoinduced absorptions and bleaches independently and confirms that features due to band gap renormalization are longer-lived than in transient absorption spectra.« less

Site-selective nitrogen isotopic ratio measurement of nitrous oxide using a TE-cooled CW-RT-QCL based spectrometer.

PubMed

Li, Jingsong; Zhang, Lizhu; Yu, Benli

2014-12-10

The feasibility of laser spectroscopic isotopic composition measurements of atmospheric N2O was demonstrated, although making them useful will require further improvements. The system relies on a thermoelectrically (TE) cooled continuous-wave (CW) room temperature (RT) quantum cascade laser source emitting wavelength of around 4.6μm, where strong fundamental absorption bands occur for the considered specie and its isotopomers. The analysis technique is based on wavelength modulation spectroscopy with second-harmonic detection and the combination of long-path absorption cell. Primary laboratory tests have been performed to estimate the achievable detection limits and the signal reproducibility levels in view of possible measurements of (15)N/(14)N and (18)O/(16)O isotope ratios. The experiment results showed that the site-selective (15)N/(14)N ratio can be measured with a precision of 3‰ with 90s averaging time using natural-abundance N2O sample of 12.7ppm. Copyright © 2014 Elsevier B.V. All rights reserved.

Apparatus and method for transient thermal infrared spectrometry

DOEpatents

McClelland, John F.; Jones, Roger W.

1991-12-03

A method and apparatus for enabling analysis of a material (16, 42) by applying a cooling medium (20, 54) to cool a thin surface layer portion of the material and to transiently generate a temperature differential between the thin surface layer portion and the lower portion of the material sufficient to alter the thermal infrared emission spectrum of the material from the black-body thermal infrared emission spectrum of the material. The altered thermal infrared emission spectrum of the material is detected by a spectrometer/detector (28, 50) while the altered thermal infrared emission spectrum is sufficiently free of self-absorption by the material of the emitted infrared radiation. The detection is effected prior to the temperature differential propagating into the lower portion of the material to an extent such that the altered thermal infrared emission spectrum is no longer sufficiently free of self-absorption by the material of emitted infrared radiation, so that the detected altered thermal infrared emission spectrum is indicative of the characteristics relating to the molecular composition of the material.

A Catalog of Cool Dwarf Targets for the Transiting Exoplanet Survey Satellite

NASA Astrophysics Data System (ADS)

Muirhead, Philip S.; Dressing, Courtney D.; Mann, Andrew W.; Rojas-Ayala, Bárbara; Lépine, Sébastien; Paegert, Martin; De Lee, Nathan; Oelkers, Ryan

2018-04-01

We present a catalog of cool dwarf targets (V-J> 2.7, T eff ≲ 4000 K) and their stellar properties for the upcoming Transiting Exoplanet Survey Satellite (TESS), for the purpose of determining which cool dwarfs should be observed using two minute observations. TESS has the opportunity to search tens of thousands of nearby, cool, late K- and M-type dwarfs for transiting exoplanets, an order of magnitude more than current or previous transiting exoplanet surveys, such as Kepler, K2, and ground-based programs. This necessitates a new approach to choosing cool dwarf targets. Cool dwarfs are chosen by collating parallax and proper motion catalogs from the literature and subjecting them to a variety of selection criteria. We calculate stellar parameters and TESS magnitudes using the best possible relations from the literature while maintaining uniformity of methods for the sake of reproducibility. We estimate the expected planet yield from TESS observations using statistical results from the Kepler mission, and use these results to choose the best targets for two minute observations, optimizing for small planets for which masses can conceivably be measured using follow-up Doppler spectroscopy by current and future Doppler spectrometers. The catalog is available in machine readable format and is incorporated into the TESS Input Catalog and TESS Candidate Target List until a more complete and accurate cool dwarf catalog identified by ESA’s Gaia mission can be incorporated.

Recent developments in turning hardened steels - A review

NASA Astrophysics Data System (ADS)

Sivaraman, V.; Prakash, S.

2017-05-01

Hard materials ranging from HRC 45 - 68 such as hardened AISI H13, AISI 4340, AISI 52100, D2 STL, D3 STEEL Steel etc., need super hard tool materials to machine. Turning of these hard materials is termed as hard turning. Hard turning makes possible direct machining of the hard materials and also eliminates the lubricant requirement and thus favoring dry machining. Hard turning is a finish turning process and hence conventional grinding is not required. Development of the new advanced super hard tool materials such as ceramic inserts, Cubic Boron Nitride, Polycrystalline Cubic Boron Nitride etc. enabled the turning of these materials. PVD and CVD methods of coating have made easier the production of single and multi layered coated tool inserts. Coatings of TiN, TiAlN, TiC, Al2O3, AlCrN over cemented carbide inserts has lead to the machining of difficult to machine materials. Advancement in the process of hard machining paved way for better surface finish, long tool life, reduced tool wear, cutting force and cutting temperatures. Micro and Nano coated carbide inserts, nanocomposite coated PCBN inserts, micro and nano CBN coated carbide inserts and similar developments have made machining of hardened steels much easier and economical. In this paper, broad literature review on turning of hardened steels including optimizing process parameters, cooling requirements, different tool materials etc., are done.

ISOTOPE CONVERSION DEVICE

DOEpatents

Wigner, E.P.; Young, G.J.; Ohlinger, L.A.

1957-12-01

This patent relates to nuclear reactors of tbe type utilizing a liquid fuel and designed to convert a non-thermally fissionable isotope to a thermally fissionable isotope by neutron absorption. A tank containing a reactive composition of a thermally fissionable isotope dispersed in a liquid moderator is disposed within an outer tank containing a slurry of a non-thermally fissionable isotope convertible to a thermally fissionable isotope by neutron absorption. A control rod is used to control the chain reaction in the reactive composition and means are provided for circulating and cooling the reactive composition and slurry in separate circuits.

Mid-infrared two photon absorption sensitivity of commercial detectors

NASA Astrophysics Data System (ADS)

Boiko, D. L.; Antonov, A. V.; Kuritsyn, D. I.; Yablonskiy, A. N.; Sergeev, S. M.; Orlova, E. E.; Vaks, V. V.

2017-10-01

We report on broad-band two-photon absorption (TPA) in several commercially available MIR inter-band bulk semiconductor photodetectors with the spectral cutoff in the range of 4.5-6 μm. The highest TPA responsivity of 2 × 10-5 A.mm2/W2 is measured for a nitrogen-cooled InSb photovoltaic detector. Its performance as a two-photon detector is validated by measuring the second-order interferometric autocorrelation function of a multimode quantum cascade laser emitting at the wavelength of 8 μm.

Packed fluidized bed blanket for fusion reactor

DOEpatents

Chi, John W. H.

1984-01-01

A packed fluidized bed blanket for a fusion reactor providing for efficient radiation absorption for energy recovery, efficient neutron absorption for nuclear transformations, ease of blanket removal, processing and replacement, and on-line fueling/refueling. The blanket of the reactor contains a bed of stationary particles during reactor operation, cooled by a radial flow of coolant. During fueling/refueling, an axial flow is introduced into the bed in stages at various axial locations to fluidize the bed. When desired, the fluidization flow can be used to remove particles from the blanket.

Spot temperatures and area coverages on active dwarf stars

NASA Technical Reports Server (NTRS)

Sarr, Steven H.; Neff, James E.

1990-01-01

Two active K dwarfs are examined to determine the temperatures of the stars and to estimate the locations and sizes of cool spots on the stellar surfaces. Two wavelength regions with TiO absorption bands at different temperature sensitivities are modeled simultaneously using the method developed by Huenemoerder and Ramsey (1987). The spectrum of BD +26deg730 shows excess absorption in the TiO band, and the absence of the 8860 A band in HD 82558 indicates that its spots are warmer than those of BD +26deg730.

Personal cooling in hot workings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tuck, M.A.

1999-07-01

The number of mines experiencing climatic difficulties worldwide is increasing. In a large number of cases these climatic difficulties are confined to working areas only or to specific locations within working areas. Thus the problem in these mines can be described as highly localized, due to a large extent not to high rock temperatures but due to machine heat loads and low airflow rates. Under such situations conventional means of controlling the climate can be inapplicable and/or uneconomic. One possible means of achieving the required level of climatic control, to ensure worker health and safety whilst achieving economic gains, ismore » to adopt a system of active man cooling. This is the reverse of normal control techniques where the cooling power of the ventilating air is enhanced in some way. Current methods of active man cooling include ice jackets and various umbilical cord type systems. These have numerous drawbacks, such as limited useful exposure times and limitations to worker mobility. The paper suggests an alternative method of active man cooling than those currently available and reviews the design criteria for such a garment. The range of application of such a garment is discussed, under both normal and emergency situations.« less

Contributions a la caracterisation et a l'amelioration de l'usinabilite de pieces d'acier elaborees par metallurgie des poudres

NASA Astrophysics Data System (ADS)

Boilard, Patrick

Even though powder metallurgy (P/M) is a near net shape process, a large number of parts still require one or more machining operations during the course of their elaboration and/or their finishing. The main objectives of the work presented in this thesis are centered on the elaboration of blends with enhanced machinability, as well as helping with the definition and in the characterization of the machinability of P/M parts. Enhancing machinability can be done in various ways, through the use of machinability additives and by decreasing the amount of porosity of the parts. These different ways of enhancing machinability have been investigated thoroughly, by systematically planning and preparing series of samples in order to obtain valid and repeatable results leading to meaningful conclusions relevant to the P/M domain. Results obtained during the course of the work are divided into three main chapters: (1) the effect of machining parameters on machinability, (2) the effect of additives on machinability, and (3) the development and the characterization of high density parts obtained by liquid phase sintering. Regarding the effect of machining parameters on machinability, studies were performed on parameters such as rotating speed, feed, tool position and diameter of the tool. Optimal cutting parameters are found for drilling operations performed on a standard FC-0208 blend, for different machinability criteria. Moreover, study of material removal rates shows the sensitivity of the machinability criteria for different machining parameters and indicates that thrust force is more regular than tool wear and slope of the drillability curve in the characterization of machinability. The chapter discussing the effect of various additives on machinability reveals many interesting results. First, work carried out on MoS2 additions reveals the dissociation of this additive and the creation of metallic sulphides (namely CuxS sulphides) when copper is present. Results also show that it is possible to reduce the amount of MoS2 in the blend so as to lower the dimensional change and the cost (blend Mo8A), while enhancing machinability and keeping hardness values within the same range (70 HRB). Second, adding enstatite (MgO·SiO2) permits the observation of the mechanisms occurring with the use of this additive. It is found that the stability of enstatite limits the diffusion of graphite during sintering, leading to the presence of free graphite in the pores, thus enhancing machinability. Furthermore, a lower amount of graphite in the matrix leads to a lower hardness, which is also beneficial to machinability. It is also found that the presence of copper enhances the diffusion of graphite, through the formation of a liquid phase during sintering. With the objective of improving machinability by reaching higher densities, blends were developed for densification through liquid phase sintering. High density samples are obtained (>7.5 g/cm3) for blends prepared with Fe-C-P constituents, namely with 0.5%P and 2.4%C. By systematically studying the effect of different parameters, the importance of the chemical composition (mainly the carbon content) and the importance of the sintering cycle (particularly the cooling rate) are demonstrated. Moreover, various heat treatments studied illustrate the different microstructures achievable for this system, showing various amounts of cementite, pearlite and free graphite. Although the machinability is limited for samples containing large amounts of cementite, it can be greatly improved with very slow cooling, leading to graphitization of the carbon in presence of phosphorus. Adequate control of the sintering cycle on samples made from FGS1625 powder leads to the obtention of high density (≥7.0 g/cm 3) microstructures containing various amounts of pearlite, ferrite and free graphite. Obtaining ferritic microstructures with free graphite designed for very high machinability (tool wear <1.0%) or fine pearlitic microstructures with excellent mechanical properties (transverse rupture strength >1600 MPa) is therefore possible. These results show that improvement of machinability through higher densities is limited by microstructure. Indeed, for the studied samples, microstructure is dominant in the determination of machinability, far more important than density, judging by the influence of cementite or of the volume fraction of free graphite on machinability for example. (Abstract shortened by UMI.)

Solar cooling - comparative study between thermal and electrical use in industrial buildings

NASA Astrophysics Data System (ADS)

Badea, N.; Badea, G. V.; Epureanu, A.; Frumuşanu, G.

2016-08-01

The increase in the share of renewable energy sources together with the emphasis on the need for energy security bring to a spotlight the field of trigeneration autonomous microsystems, as a solution to cover the energy consumptions, not only for isolated industrial buildings, but also for industrial buildings located in urban areas. The use of solar energy for cooling has been taken into account to offer a cooling comfort in the building. Cooling and air- conditioned production are current applications promoting the use of solar energy technologies. Solar cooling systems can be classified, depending on the used energy, in electrical systems using mechanical compression chillers and systems using thermal compression by absorption or adsorption. This comparative study presents the main strengths and weaknesses of solar cooling obtained: i) through the transformation of heat resulted from thermal solar panels combined with adsorption chillers, and ii) through the multiple conversion of electricity - photovoltaic panels - battery - inverter - combined with mechanical compression chillers. Both solutions are analyzed from the standpoints of energy efficiency, dynamic performances (demand response), and costs sizes. At the end of the paper, experimental results obtained in the climatic condition of Galafi city, Romania, are presented.

Absorption coefficients of solid NH3 from 50 to 7000 per cm

NASA Technical Reports Server (NTRS)

Sill, G.; Fink, U.; Ferraro, J. R.

1980-01-01

Thin-film spectra of solid NH3 at a resolution of 1 per cm were used to determine its absorption coefficient over the range 50-7000 per cm. The thin films were formed inside a liquid N2 cooled dewar using a variety of substrates and dewar windows. The spectra were recorded with two Fourier spectrometers, one covering the range from 1 to 4 microns and the other from 2.6 to 200 microns. The thickness of the films was measured with a laser interference technique. The absorption coefficients were determined by application of Lambert's law and by a fitting procedure to the observed spectra using thin-film theory. Good agreement was found with the absorption coefficients recently determined by other investigators over a more restricted wavelength range. A metastable phase was observed near a temperature of 90 K and its absorption coefficient is reported. No other major spectral changes with temperature were noted for the range 88-120 K.

Satellite and Ground-based Radiometers Reveal Much Lower Dust Absorption of Sunlight than Used in Climate Models

NASA Technical Reports Server (NTRS)

Kaufman, Y. J.; Tanre, D.; Dubovik, O.; Karnieli, A.; Remer, L. A.; Einaudi, Franco (Technical Monitor)

2000-01-01

The ability of dust to absorb solar radiation and heat the atmosphere is one of the main uncertainties in climate modeling and the prediction of climate change. Dust absorption is not well known due to limitations of in situ measurements. New techniques to measure dust absorption are needed in order to assess the impact of dust on climate. Here we report two new independent remote sensing techniques that provide sensitive measurements of dust absorption. Both are based on remote sensing. One uses satellite spectral measurements, the second uses ground based sky measurements from the AERONET network. Both techniques demonstrate that Saharan dust absorption of solar radiation is several times smaller than the current international standards. Dust cooling of the earth system in the solar spectrum is therefore significantly stronger than recent calculations indicate. We shall also address the issue of the effects of dust non-sphericity on the aerosol optical properties.

Organic absorption gas-fired residential heat pump

NASA Astrophysics Data System (ADS)

Murphy, K. P.

The development program of a system utilizing a new absorption pair, R133a (CF3CH2Cl) as the refigerant, and ETFE (ethyletra-hydrofurfury lether) as the absorber fluid, is described. A diagram of the basic configuration is shown. The cooling mode and the heating mode are discussed. Six units of an early hardware design were constructed and tested. Two of these units were placed in home heating service during the 1980-81 season. A market evaluation of the business potential of the absorption system was made, identifying location and size of the likely market for such a system. A performance simulation analysis was performed for seven cities in the US. From these, general characteristics of the areas having the greatest performance benefits were established.

Simulating the escaping atmospheres of hot gas planets in the solar neighborhood

NASA Astrophysics Data System (ADS)

Salz, M.; Czesla, S.; Schneider, P. C.; Schmitt, J. H. M. M.

2016-02-01

Absorption of high-energy radiation in planetary thermospheres is generally believed to lead to the formation of planetary winds. The resulting mass-loss rates can affect the evolution, particularly of small gas planets. We present 1D, spherically symmetric hydrodynamic simulations of the escaping atmospheres of 18 hot gas planets in the solar neighborhood. Our sample only includes strongly irradiated planets, whose expanded atmospheres may be detectable via transit spectroscopy using current instrumentation. The simulations were performed with the PLUTO-CLOUDY interface, which couples a detailed photoionization and plasma simulation code with a general MHD code. We study the thermospheric escape and derive improved estimates for the planetary mass-loss rates. Our simulations reproduce the temperature-pressure profile measured via sodium D absorption in HD 189733 b, but show still unexplained differences in the case of HD 209458 b. In contrast to general assumptions, we find that the gravitationally more tightly bound thermospheres of massive and compact planets, such as HAT-P-2 b are hydrodynamically stable. Compact planets dispose of the radiative energy input through hydrogen Lyα and free-free emission. Radiative cooling is also important in HD 189733 b, but it decreases toward smaller planets like GJ 436 b. Computing the planetary Lyα absorption and emission signals from the simulations, we find that the strong and cool winds of smaller planets mainly cause strong Lyα absorption but little emission. Compact and massive planets with hot, stable thermospheres cause small absorption signals but are strong Lyα emitters, possibly detectable with the current instrumentation. The absorption and emission signals provide a possible distinction between these two classes of thermospheres in hot gas planets. According to our results, WASP-80 and GJ 3470 are currently the most promising targets for observational follow-up aimed at detecting atmospheric Lyα absorption signals. Simulated atmospheres are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/586/A75

A ROSAT HRI observation of the cooling flow cluster MS0839.9+2938.

NASA Astrophysics Data System (ADS)

Nesci, R.; Perola, G. C.; Wolter, A.

1995-07-01

A ROSAT HRI observation of the cluster MS0839.9+2938 at z=0.194 is presented. It confirms the earlier suggestion, based on the detection of extended Hα emission, that the inner regions of this cluster are dominated by a cooling flow. Within the cooling radius a marginally significant evidence is found of structures in the surface brightness, which are similar to those more significantly found in two less distant cooling flow clusters (A2029 and 2A0335+096). We note that, although its barycentre falls on top of the central giant elliptical galaxy, the azimuthally averaged brightness distribution does not peak at that position and actually stays flat out to about 40kpc (10") from the galaxy centre. From comparison with the two clusters mentioned above, this situation seems peculiar, and it is suggested that it could arise from photoelectric absorption by cold gas within the cooling flow, with an equivalent column density in the order of 5x10^21^/cm^2^ within ~10" from the centre, a factor 2-3 higher than the column spectroscopically detected in the comparison clusters.

Direct fired heat exchanger

DOEpatents

Reimann, Robert C.; Root, Richard A.

1986-01-01

A gas-to-liquid heat exchanger system which transfers heat from a gas, generally the combustion gas of a direct-fired generator of an absorption machine, to a liquid, generally an absorbent solution. The heat exchanger system is in a counterflow fluid arrangement which creates a more efficient heat transfer.

A general derivation and quantification of the third law of thermodynamics.

PubMed

Masanes, Lluís; Oppenheim, Jonathan

2017-03-14

The most accepted version of the third law of thermodynamics, the unattainability principle, states that any process cannot reach absolute zero temperature in a finite number of steps and within a finite time. Here, we provide a derivation of the principle that applies to arbitrary cooling processes, even those exploiting the laws of quantum mechanics or involving an infinite-dimensional reservoir. We quantify the resources needed to cool a system to any temperature, and translate these resources into the minimal time or number of steps, by considering the notion of a thermal machine that obeys similar restrictions to universal computers. We generally find that the obtainable temperature can scale as an inverse power of the cooling time. Our results also clarify the connection between two versions of the third law (the unattainability principle and the heat theorem), and place ultimate bounds on the speed at which information can be erased.

A general derivation and quantification of the third law of thermodynamics

PubMed Central

Masanes, Lluís; Oppenheim, Jonathan

2017-01-01

The most accepted version of the third law of thermodynamics, the unattainability principle, states that any process cannot reach absolute zero temperature in a finite number of steps and within a finite time. Here, we provide a derivation of the principle that applies to arbitrary cooling processes, even those exploiting the laws of quantum mechanics or involving an infinite-dimensional reservoir. We quantify the resources needed to cool a system to any temperature, and translate these resources into the minimal time or number of steps, by considering the notion of a thermal machine that obeys similar restrictions to universal computers. We generally find that the obtainable temperature can scale as an inverse power of the cooling time. Our results also clarify the connection between two versions of the third law (the unattainability principle and the heat theorem), and place ultimate bounds on the speed at which information can be erased. PMID:28290452

Soviet-West German Symposium on Heat Transfer in Cryogenic Systems, 3rd, Kharkov, Ukrainian SSR, Oct. 9-11, 1989, Proceedings

NASA Astrophysics Data System (ADS)

1990-04-01

The papers presented in this volume describe a rotating cryostat for the simulation of mechanical, thermal, and hydraulic processes in superconducting rotors; the problems of cooling the fully superconducting generator stator; an investigation of natural circulation by optical methods; and a method of calculating void fraction for vapor-liquid or gas-liquid flow conditions. Attention is given to an experimental study of the processes of He-3 boiling and condensation, heat transfer in He II at a slow variation of the heat load, an investigation of He II flow crisis in porous media, and cryogenic heat pipes. Other papers are on the stability of rotating superconducting windings for electric machines, the stability of high-temperature superconductors cooled by liquid nitrogen, a calculation of the transpiration cooling of a cylindrical porous wall, and pressure losses in boiling nitrogen flow through horizontal channels.

Thermal degradation products from PVC film in food-wrapping operations.

PubMed

Boettner, E A; Ball, G L

1980-07-01

Thermal degradation products of polyvinyl chloride (PVC) food-wrap films were studied under simulated supermarket conditons using a commercial wrapping machine with either a hot wire or a cool rod cutting device. A sampling hood was constructed around the wire/rod to confine and allow collection of thermal degradation products produced. Compounds analyzed and normal concentration ranges found included hydrogen chloride (1-10 micrograms per cut), plasticizer (1-50 micrograms per cut), benzene and toluene (each < 5-20 ng per cut), acrolein (25-150 ng per cut), and carbon monoxide (2-4 micrograms per cut) using the hot wire. Room air samples, collected during hot-wire cutting without the sampling hood, had < 0.25 ppm hydrogen chloride. Using the cool-rod cutting device hydrogen chloride, benzene, and toluene were not detected. Plasticizer was detected (25-86 micrograms per cut) using the cool rod.

Method of controlling the side wall thickness of a turbine nozzle segment for improved cooling

DOEpatents

Burdgick, Steven Sebastian

2002-01-01

A gas turbine nozzle segment has outer and inner bands and a vane extending therebetween. Each band has a side wall, a cover and an impingement plate between the cover and nozzle wall defining two cavities on opposite sides of the impingement plate. Cooling steam is supplied to one cavity for flow through apertures of the impingement plate to cool the nozzle wall. The side wall of the band has an inturned flange defining with the nozzle wall an undercut region. The outer surface of the side wall is provided with a step prior to welding the cover to the side wall. A thermal barrier coating is applied in the step and, after the cover is welded to the side wall, the side wall is finally machined to a controlled thickness removing all, some or none of the coating.

Design and Simulation of a Matching System into the Helical Cooling Channel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoshikawa, C.; Ankenbrandt, C.; Johnson, R. P.

2014-07-01

Muon colliders could provide the most sensitive measurement of the Higgs mass and return the US back to the Energy Frontier. Central to the capabilities of muon colliders are the cooling channels that provide the extraordinary reduction in emittance required for the precise Higgs mass measurement and increased luminosity for enhanced discovery potential of an Energy Frontier Machine. The Helical Cooling Channel (HCC) is able to achieve such emittance reduction and matching sections within the HCC have been successfully designed in the past with lossless transmission and no emittance growth. However, matching into the HCC from a straight solenoid posesmore » a challenge, since a large emittance beam must cross transition. We elucidate on the challenge and present evaluations of two solutions, along with concepts to integrate the operations of a Charge Separator and match into the HCC.« less

Probing the cool interstellar and circumgalactic gas of three massive lensing galaxies at z = 0.4-0.7

NASA Astrophysics Data System (ADS)

Zahedy, Fakhri S.; Chen, Hsiao-Wen; Rauch, Michael; Wilson, Michelle L.; Zabludoff, Ann

2016-05-01

We present multisightline absorption spectroscopy of cool gas around three lensing galaxies at z = 0.4-0.7. These lenses have half-light radii re = 2.6-8 kpc and stellar masses of log M*/M⊙ = 10.9-11.4, and therefore resemble nearby passive elliptical galaxies. The lensed QSO sightlines presented here occur at projected distances of d = 3-15 kpc (or d ≈ 1-2 re) from the lensing galaxies, providing for the first time an opportunity to probe both interstellar gas at r ˜ re and circumgalactic gas at larger radii r ≫ re of these distant quiescent galaxies. We observe distinct gas absorption properties among different lenses and among sightlines of individual lenses. Specifically, while the quadruple lens for HE 0435-1223 shows no absorption features to very sensitive limits along all four sightlines, strong Mg II, Fe II, Mg I, and Ca II absorption transitions are detected along both sightlines near the double lens for HE 0047-1756, and in one of the two sightlines near the double lens for HE 1104-1805. The absorbers are resolved into 8-15 individual components with a line-of-sight velocity spread of Δ v ≈ 300-600 km s-1. The large ionic column densities, log N ≳ 14, observed in two components suggest that these may be Lyman limit or damped Ly α absorbers with a significant neutral hydrogen fraction. The majority of the absorbing components exhibit a uniform supersolar Fe/Mg ratio with a scatter of <0.1 dex across the full Δ v range. Given a predominantly old stellar population in these lensing galaxies, we argue that the observed large velocity width and Fe-rich abundance pattern can be explained by SNe Ia enriched gas at radius r ˜ re. We show that additional spatial constraints in line-of-sight velocity and relative abundance ratios afforded by a multisightline approach provide a powerful tool to resolve the origin of chemically enriched cool gas in massive haloes.

Health hazard evaluation report HETA 85-039-1723, E. L. Smithe Machine Company, Duncansville, Pennsylvania

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bennett, D.E.

1986-08-01

The International Association of Machinists Local 2348 requested an investigation of reported skin rashes and headaches associated with cutting and cooling oils and solvents used in the machine shop. Of 62 employees interviewed, 42 had experienced skin problems occurring on their hands and arms including red skin, dry skin, cracked skin, or itchy skin, related to chemical exposures at the workplace. Xerosis, lichenification, or eczema of the hands and arms were noted on examination of 17 employees of the Lathe Department and 18 of those from the Milling Department. Respiratory and neurological complaints were also found among these employees. Themore » author concluded that the incidence of hand and arm xerosis and eczema in workers in the machining area may be associated with exposure to cutting oils. The author recommends that changes be made to minimize skin exposure and provide adequate ventilation and humidification.« less

Two phase gap cooling of an electrical machine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shoykhet, Boris A.

2016-10-04

An electro-dynamic machine has a rotor and stator with a gap therebetween. The machine has a frame defining a hollow interior with end cavities on axially opposite ends of the frame. A gas circulating system has an inlet that supplies high pressure gas to the frame interior and an outlet to collect gas passing therethrough. A liquid coolant circulating system has an inlet that supplies coolant to the frame interior and an outlet that collects coolant passing therethrough. The coolant inlet and gas inlet are generally located on the frame in a manner to allow coolant from the coolant inletmore » to flow with gas from the gas inlet to the gap. The coolant outlet and gas outlet are generally located on the frame in a manner to allow the coolant to be separated from the gas with the separated coolant and gas collected for circulation through their respective circulating systems.« less

{sup 85}Rb tunable-interaction Bose-Einstein condensate machine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Altin, P. A.; Robins, N. P.; Doering, D.

We describe our experimental setup for creating stable Bose-Einstein condensates (BECs) of {sup 85}Rb with tunable interparticle interactions. We use sympathetic cooling with {sup 87}Rb in two stages, initially in a tight Ioffe-Pritchard magnetic trap and subsequently in a weak, large-volume, crossed optical dipole trap, using the 155 G Feshbach resonance to manipulate the elastic and inelastic scattering properties of the {sup 85}Rb atoms. Typical {sup 85}Rb condensates contain 4x10{sup 4} atoms with a scattering length of a=+200a{sub 0}. Many aspects of the design presented here could be adapted to other dual-species BEC machines, including those involving degenerate Fermi-Bose mixtures.more » Our minimalist apparatus is well suited to experiments on dual-species and spinor Rb condensates, and has several simplifications over the {sup 85}Rb BEC machine at JILA, which we discuss at the end of this article.« less

Nanofibrous membrane-based absorption refrigeration system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Isfahani, RN; Sampath, K; Moghaddam, S

2013-12-01

This paper presents a study on the efficacy of highly porous nanofibrous membranes for application in membrane-based absorbers and desorbers. Permeability studies showed that membranes with a pore size greater than about one micron have a sufficient permeability for application in the absorber heat exchanger. Membranes with smaller pores were found to be adequate for the desorber heat exchanger. The membranes were implemented in experimental membrane-based absorber and desorber modules and successfully tested. Parametric studies were conducted on both absorber and desorber processes. Studies on the absorption process were focused on the effects of water vapor pressure, cooling water temperature,more » and the solution velocity on the absorption rate. Desorption studies were conducted on the effects of wall temperature, vapor and solution pressures, and the solution velocity on the desorption rate. Significantly higher absorption and desorption rates than in the falling film absorbers and desorbers were achieved. Published by Elsevier Ltd.« less

Alq3 coated silicon nanomembranes for cavity optomechanics

NASA Astrophysics Data System (ADS)

Fogliano, Francesco; Ortu, Antonio; Camposeo, Andrea; Pisignano, Dario; Ciampini, Donatella; Fuso, Francesco; Arimondo, E.

2016-09-01

The optomechanical properties of a silicon-nitride membrane mirror covered by Alq3 and Silver layers are investigated. Excitation at two laser wavelengths, 780 and 405 nm, corresponding to different absorptions of the multilayer, is examined. Such dual driving will lead to a more flexible optomechanical operation. Topographic reconstruction of the whole static membrane deformation and cooling of the membrane oscillations are reported. The cooling, observed for blue laser detuning and produced by bolometric forces, is deduced from the optomechanical damping of the membrane eigenfrequency. We determine the presence of different contributions to the photothermal response of the membrane.

Solar-powered air-conditioning

NASA Technical Reports Server (NTRS)

Clark, D. C.; Rousseau, J.

1977-01-01

Report focuses on recent study on development of solar-powered residential air conditioners and is based on selected literature through 1975. Its purposes are to characterize thermal and mechanical systems that might be useful in development of Rankine-cycle approach to solar cooling and assessment of a Lithium Bromide/Water absorption cycle system.

Minimization of the Effects of Secondary Reactions on Turbine Film Cooling in a Fuel Rich Environment

DTIC Science & Technology

2014-06-02

the instrumentation block ..................................... 57 Table 4.1: Flame Length Results...91 Table 4.2: Five Row Flame Lengths , Blowing Ratio Sweep .......................................... 123 Table...4.3: Five Row Flame Lengths , Equivalence Ratio Sweep .................................... 124 Table 4.4: Five Row - Wall Absorption Parameter

Observations of the Ultraviolet Spectra of Carbon White Dwarfs

NASA Technical Reports Server (NTRS)

Wagner, G. A.

1982-01-01

Strong ultraviolet carbon lines were detected in additional white DC (continuous visual spectra) dwarfs using the IUE. These lines are not seen in the ultraviolet spectrum of the cool DC star Stein 2051 B. The bright DA white dwarf LB 3303 has a strong unidentified absorption near lambda 1400.

Experimental investigation on the effects of cooling system on surface quality in high speed milling of an aluminium alloy

NASA Astrophysics Data System (ADS)

Chirita, B.; Tampu, N. C.; Brabie, G.; Radu, M. C.

2016-08-01

Surface quality is often an important feature of industrial products, not only from the impact it has on the aesthetic aspect but also for the functional role of the parts. High quality surface increases corrosion resistance, assures a longer life cycle for the product and lowers the wear. For a machined part, surface quality is influenced by a series of factors such as the material of the part, the process type, tool geometry, cutting parameters or the cooling system. The choice of the cooling system is especially important, taking into account that the proper conditions will not only assure a superior surface quality, but will also lower the costs and reduce the environmental impact and health risks. The present study aims to investigate the performance of the cooling system and the effect of the cutting parameters on the characteristics of the surfaces resulted from high speed face milling of some parts made of Al 7050-T7451 aluminium alloy. Dry cutting conditions and minimum quantity lubrication (MQL) where used. The results were analysed using analysis of variance (ANOVA).

Observing microphysical structures and hydrometeor phase in convection with ARM active sensors

NASA Astrophysics Data System (ADS)

Riihimaki, L.; Comstock, J. M.; Luke, E. P.; Thorsen, T. J.; Fu, Q.

2016-12-01

The existence and distribution of super-cooled liquid water within convective clouds impacts the microphysical processes responsible for cloud radiative and lifetime effects. Yet few observations of cloud phase are available within convection and associated stratiform anvils. Here we identify super-cooled liquid layers within convection and associated stratiform clouds using measured radar Doppler spectra from vertically pointing Ka-band cloud radar and Raman Lidar, capitalizing on the strengths of both instruments. Observations from these sensors are used to show that liquid exists in patches within the cloud, rather than in uniform layers, impacting the growth and formation of ice. While a depolarization lidar like the Raman Lidar is a trusted measurement for identifying super-cooled liquid, the lidar attenuates at an optical depth of around three, limiting its ability to probe the full cloud. The use of the radar Doppler spectra is particularly valuable for this purpose because it allows observations within optically thicker clouds. We demonstrate a new method for identifying super-cooled liquid objectively from the radar Doppler spectra using machine-learning techniques.

Toward stand-off open-path measurements of NO and NO(2) in the sub-parts per million meter range using quantum cascade lasers (QCLs) in the intra-pulse absorption mode.

PubMed

Reidl-Leuthner, Christoph; Lendl, Bernhard

2013-12-01

Two thermoelectrically cooled mid-infrared distributed feedback quantum cascade lasers operated in pulsed mode have been used for the quasi-simultaneous determination of NO and NO2 in the sub-parts per million meter (sub-ppm-m) range. Using a beam splitter, the beams of the two lasers were combined and sent to a retro-reflector. The returned light was recorded with a thermoelectrically cooled mercury cadmium telluride detector with a rise time of 4 ns. Alternate operation of the lasers with pulse lengths of 300 ns and a repetition rate of 66 kHz allowed quasi-simultaneous measurements. During each pulse the laser temperature increased, causing a thermal chirp of the laser line of up to 1.3 cm(-1). These laser chirps were sufficient to scan rotational bands of NO centered at 1902 cm(-1) and NO2 located at 1632 cm(-1). In that way an absorption spectrum could be recorded from a single laser pulse. Currently achieved limits of detection are 600 parts per billion meter (ppb-m) for NO and 260 ppb-m for NO2 using signal averaging over 1 min. This work presents the first steps toward a portable stand-off, open-path instrument that uses thermoelectrically cooled detector and lasers.

Real evaporative cooling efficiency of one-layer tight-fitting sportswear in a hot environment.

PubMed

Wang, F; Annaheim, S; Morrissey, M; Rossi, R M

2014-06-01

Real evaporative cooling efficiency, the ratio of real evaporative heat loss to evaporative cooling potential, is an important parameter to characterize the real cooling benefit for the human body. Previous studies on protective clothing showed that the cooling efficiency decreases with increasing distance between the evaporation locations and the human skin. However, it is still unclear how evaporative cooling efficiency decreases as the moisture is transported from the skin to the clothing layer. In this study, we performed experiments with a sweating torso manikin to mimic three different phases of moisture absorption in one-layer tight-fitting sportswear. Clothing materials Coolmax(®) (CM; INVISTA, Wichita, Kansas, USA; 100%, profiled cross-section polyester fiber), merino wool (MW; 100%), sports wool (SW; 50% wool, 50% polyester), and cotton (CO; 100%) were selected for the study. The results demonstrated that, for the sportswear materials tested, the real evaporative cooling efficiency linearly decreases with the increasing ratio of moisture being transported away from skin surface to clothing layer (adjusted R(2) >0.97). In addition, clothing fabric thickness has a negative effect on the real evaporative cooling efficiency. Clothing CM and SW showed a good ability in maintaining evaporative cooling efficiency. In contrast, clothing MW made from thicker fabric had the worst performance in maintaining evaporative cooling efficiency. It is thus suggested that thin fabric materials such as CM and SW should be used to manufacture one-layer tight-fitting sportswear. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Prediction Based Proactive Thermal Virtual Machine Scheduling in Green Clouds

PubMed Central

Kinger, Supriya; Kumar, Rajesh; Sharma, Anju

2014-01-01

Cloud computing has rapidly emerged as a widely accepted computing paradigm, but the research on Cloud computing is still at an early stage. Cloud computing provides many advanced features but it still has some shortcomings such as relatively high operating cost and environmental hazards like increasing carbon footprints. These hazards can be reduced up to some extent by efficient scheduling of Cloud resources. Working temperature on which a machine is currently running can be taken as a criterion for Virtual Machine (VM) scheduling. This paper proposes a new proactive technique that considers current and maximum threshold temperature of Server Machines (SMs) before making scheduling decisions with the help of a temperature predictor, so that maximum temperature is never reached. Different workload scenarios have been taken into consideration. The results obtained show that the proposed system is better than existing systems of VM scheduling, which does not consider current temperature of nodes before making scheduling decisions. Thus, a reduction in need of cooling systems for a Cloud environment has been obtained and validated. PMID:24737962

Installation of the Ignitor Machine at the Caorso Site

NASA Astrophysics Data System (ADS)

Migliori, S.; Pierattini, S.; Bombarda, F.; Faelli, G.; Zucchetti, M.; Coppi, B.

2008-11-01

The actual cost of building a new experiment can be considerably contained if infrastructures are already available on its envisioned site. The facilities of the Caorso site (near Piacenza, Italy) that, at present, houses a spent nuclear power station, have been analyzed in view of their utilization for the operation of the Ignitor machine. The main feature of the site is its robust connection to the electrical national power grid that can take the disturbance caused by Ignitor discharges with the highest magnetic fields and plasma currents, avoiding the need for rotating flywheels generators. Other assets include a vast building that can be modified to house the machine core and the associated diagnostic systems. A layout of the Ignitor plant, including the tritium laboratory and other service areas, the distribution of the components of the electrical power supply system and of the He gas cooling sytem are presented. Relevant safety issues have been analyzed, based on the in depth activation analysis of the machine components carried out by means of the FISPAC code. Waste management and environment impact issues, including risk to the population assessments, have also been addressed.

Infrared Astronomy Satellite

NASA Astrophysics Data System (ADS)

Ferrera, G. A.

1981-09-01

In 1982, the Infrared Astronomy Satellite (IRAS) will be launched into a 900-km sun-synchronous (twilight) orbit to perform an unbiased, all-sky survey of the far-infrared spectrum from 8 to 120 microns. Observations telemetered to ground stations will be compiled into an IR astronomy catalog. Attention is given the cryogenically cooled, 60-cm Ritchey-Chretien telescope carried by the satellite, whose primary and secondary mirrors are fabricated from beryllium by means of 'Cryo-Null Figuring'. This technique anticipates the mirror distortions that will result from cryogenic cooling of the telescope and introduces dimensional compensations for them during machining and polishing. Consideration is also given to the interferometric characterization of telescope performance and Cryo/Thermal/Vacuum simulated space environment testing.

40 CFR 63.323 - Test methods and monitoring.

Code of Federal Regulations, 2011 CFR

2011-07-01

... air-perchloroethylene gas-vapor stream on the outlet side of the refrigerated condenser on a dry-to-dry machine, dryer, or reclaimer with a temperature sensor to determine if it is equal to or less than 7.2 °C (45 °F) before the end of the cool-down or drying cycle while the gas-vapor stream is flowing...

40 CFR 63.323 - Test methods and monitoring.

Code of Federal Regulations, 2010 CFR

2010-07-01

... air-perchloroethylene gas-vapor stream on the outlet side of the refrigerated condenser on a dry-to-dry machine, dryer, or reclaimer with a temperature sensor to determine if it is equal to or less than 7.2 °C (45 °F) before the end of the cool-down or drying cycle while the gas-vapor stream is flowing...

19. WHILE AUTOMATION REDUCED SOME LABORINTENSIVE POSITIONS, THESE LARGE ROTATING ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

19. WHILE AUTOMATION REDUCED SOME LABOR-INTENSIVE POSITIONS, THESE LARGE ROTATING CLEANING MACHINES WHICH TUMBLED CASTINGS OVER EACH OTHER TO BREAK OFF EXCESS MATERIAL WHILE QUICKLY COOLING THE METALS IN THE MALLEABLE FOUNDRY PRIOR TO ANNEALING, STILL REQUIRED HAND SEPARATION OF THE EXCESS MATERIAL, CA. 1950. - Stockham Pipe & Fittings Company, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

Radiative heat pumping from the Earth using surface phonon resonant nanoparticles.

PubMed

Gentle, A R; Smith, G B

2010-02-10

Nanoparticles that have narrow absorption bands that lie entirely within the atmosphere's transparent window from 7.9 to 13 mum can be used to radiatively cool to temperatures that are well below ambient. Heating from incoming atmospheric radiation in the remainder of the Planck radiation spectrum, where the atmosphere is nearly "black", is reduced if the particles are dopants in infrared transmitting polymers, or in transmitting coatings on low emittance substrates. Crystalline SiC nanoparticles stand out with a surface phonon resonance from 10.5 to 13 mum clear of the atmospheric ozone band. Resonant SiO(2) nanoparticles are complementary, absorbing from 8 to 10 mum, which includes atmospheric ozone emissions. Their spectral location has made SiC nanoparticles in space dust a feature in ground-based IR astronomy. Optical properties are presented and subambient cooling performance analyzed for doped polyethylene on aluminum. A mixture of SiC and SiO(2) nanoparticles yields high performance cooling at low cost within a practical cooling rig.

Latest result of PRK with excimer laser

NASA Astrophysics Data System (ADS)

Okamoto, Shinseiro; Okamoto, Michika

1996-05-01

We have in the last two years, performed PRK operation on over 300 human myopic eyes using ArF excimer laser with a Summit 'Omnimed' machine. For the initial 53 myopic eyes we treated, results were very good for those with correction less than minus 6 diopters. However, as previously reported, we also witnessed some regression for those eyes exceeding correction of more than minus 6 diopters. To counter such ill results of PRK we devised and suggested many new procedures for PRK with very good results. One such invention is the 'Okamoto-type' cooling machine for the cornea which reduces and stabilizes cornea temperature at 0 degrees Celsius while simultaneously bathing the cornea with special cooling fluid. After the operation, EGF, fibronectin and hexapeptide were administered using eyedrops. Soft contact lenses were used to protect the cornea, improve delivery of medication to the operated area, prevent infection and inflammation and also promote uniform and faster ephiterium regrowth. We were able to document very good post-operative results using this method, thereby giving us strong assurance that we have reached a significant milestone in PRK operation. Our report today covers post operative results of the 52 eyes we operated on and tracked for more than one year.

Analysis of Minimum Quantity Lubrication (MQL) for Different Coating Tools during Turning of TC11 Titanium Alloy.

PubMed

Qin, Sheng; Li, Zhongquan; Guo, Guoqiang; An, Qinglong; Chen, Ming; Ming, Weiwei

2016-09-28

The tool coating and cooling strategy are two key factors when machining difficult-to-cut materials such as titanium alloy. In this paper, diamond coating was deposited on a commercial carbide insert as an attempt to increase the machinability of TC11 alloy during the turning process. An uncoated carbide insert and a commercial Al₂O₃/TiAlN-coated tool were also tested as a comparison. Furthermore, MQL was applied to improve the cutting condition. Cutting performances were analyzed by cutting force, cutting temperate and surface roughness measurements. Tool wears and tool lives were evaluated to find a good matchup between the tool coating and cooling strategy. According to the results, using MQL can slightly reduce the cutting force. By applying MQL, cutting temperatures and tool wears were reduced by a great amount. Besides, MQL can affect the tool wear mechanism and tool failure modes. The tool life of an Al₂O₃/TiAlN-coated tool can be prolonged by 88.4% under the MQL condition. Diamond-coated tools can obtain a good surface finish when cutting parameters and lubrication strategies are properly chosen.

Analysis of Minimum Quantity Lubrication (MQL) for Different Coating Tools during Turning of TC11 Titanium Alloy

PubMed Central

Qin, Sheng; Li, Zhongquan; Guo, Guoqiang; An, Qinglong; Chen, Ming; Ming, Weiwei

2016-01-01

The tool coating and cooling strategy are two key factors when machining difficult-to-cut materials such as titanium alloy. In this paper, diamond coating was deposited on a commercial carbide insert as an attempt to increase the machinability of TC11 alloy during the turning process. An uncoated carbide insert and a commercial Al2O3/TiAlN-coated tool were also tested as a comparison. Furthermore, MQL was applied to improve the cutting condition. Cutting performances were analyzed by cutting force, cutting temperate and surface roughness measurements. Tool wears and tool lives were evaluated to find a good matchup between the tool coating and cooling strategy. According to the results, using MQL can slightly reduce the cutting force. By applying MQL, cutting temperatures and tool wears were reduced by a great amount. Besides, MQL can affect the tool wear mechanism and tool failure modes. The tool life of an Al2O3/TiAlN-coated tool can be prolonged by 88.4% under the MQL condition. Diamond-coated tools can obtain a good surface finish when cutting parameters and lubrication strategies are properly chosen. PMID:28773926

Effects of seawater flow rate and evaporation temperature on performance of Sherbet type ice making machine

NASA Astrophysics Data System (ADS)

Son, C. H.; Yoon, J. I.; Choi, K. H.; Lee, H. K.; Lee, K. S.; Moon, C. G.; Seol, S. H.

2018-01-01

This study analyzes performance of the sherbet type ice making machine using seawater with respect to seawater volumetric flow rate, evaporation temperature, cooling water inlet and seawater inlet temperature as variables. Cooling water inlet and seawater inlet temperature are set considering average temperature of South Korea and the equator regions. Volumetric flow rate of seawater range is 0.75-1.75 LPM in this experiment. The results obtained from the experiment are as follows. As the seawater volumetric flow rate increases, or seawater inlet temperature increases, evaporation capacity tends to increase. At the point of seawater inlet temperature of 27°C and volumetric flow rate of 1.0LPM, evaporation capacity is over 2kW. On the other hand, results of COP change tendency are different from that of evaporation capacity. It appears to increase until volumetric flow rate of 1.0LPM, and decrease gradually from volumetric flow rate of 1.5LPM. This is due to the increase of compressor work to keep the evaporation pressure in accordance with the temperature of heat source. As the evaporation temperature decreases from -8 to -15°C, the evaporation capacity increases, but the COP decreases.

Method of forming shrink-fit compression seal

NASA Technical Reports Server (NTRS)

Podgorski, T. J. (Inventor)

1977-01-01

A method for making a glass-to-metal seal is described. A domed metal enclosure having a machined seal ring is fitted to a glass post machined to a slight taper and to a desired surface finish. The metal part is then heated by induction in a vacuum. As the metal part heats and expands relative to the glass post, the metal seal ring, possessing a higher coefficient of expansion than the glass post, slides down the tapered post. Upon cooling, the seal ring crushes against the glass post forming the seal. The method results in a glass-to-metal seal possessing extremely good leak resistance, while the parts are kept clean and free of the contaminants.

Crystal nucleation in metallic alloys using x-ray radiography and machine learning

PubMed Central

Arteta, Carlos; Lempitsky, Victor

2018-01-01

The crystallization of solidifying Al-Cu alloys over a wide range of conditions was studied in situ by synchrotron x-ray radiography, and the data were analyzed using a computer vision algorithm trained using machine learning. The effect of cooling rate and solute concentration on nucleation undercooling, crystal formation rate, and crystal growth rate was measured automatically for thousands of separate crystals, which was impossible to achieve manually. Nucleation undercooling distributions confirmed the efficiency of extrinsic grain refiners and gave support to the widely assumed free growth model of heterogeneous nucleation. We show that crystallization occurred in temporal and spatial bursts associated with a solute-suppressed nucleation zone. PMID:29662954

INTERIOR OVERVIEW OF CONTINUOUS CASTER WITH NO. 12 LADLE. MOLTEN ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

INTERIOR OVERVIEW OF CONTINUOUS CASTER WITH NO. 12 LADLE. MOLTEN STEEL IS POURED FROM LADLE THROUGH SHROUD TO TUNDISH. FROM TUNDISH STEEL ENTERS MOLD THROUGH SHROUD AND FORMATION OF SLAB SHELL BEGINS. AS SLAB PROGRESSES THROUGH CONTAINMENT SECTION IT IS COOLED WITH AIR MIST SPRAYS AND CONTINUES SOLIDIFICATION. UPON EXITING THE MACHINE THE SLABS ARE CUT TO DESIRED LENGTH AND IDENTIFIED. THE SLABS ARE STACKED, REMOVED FROM MACHINE AND PREPARED FOR SHIPMENT TO HOT STRIP MILL. CASTER HAS ABILITY TO PRODUCE SINGLE OR TWIN CASTS. SINGLE SLABS PRODUCED MAY BE UP TO 102 INCHES; DOUBLE SLABS UP TO 49 INCHES. - U.S. Steel, Fairfield Works, Continuous Caster, Fairfield, Jefferson County, AL

A Numerical Study of Anti-Vortex Film Cooling Designs at High Blowing Ratio

NASA Technical Reports Server (NTRS)

Heidmann, James D.

2008-01-01

A concept for mitigating the adverse effects of jet vorticity and liftoff at high blowing ratios for turbine film cooling flows has been developed and studied at NASA Glenn Research Center. This "anti-vortex" film cooling concept proposes the addition of two branched holes from each primary hole in order to produce a vorticity counter to the detrimental kidney vortices from the main jet. These vortices typically entrain hot freestream gas and are associated with jet separation from the turbine blade surface. The anti-vortex design is unique in that it requires only easily machinable round holes, unlike shaped film cooling holes and other advanced concepts. The anti-vortex film cooling hole concept has been modeled computationally for a single row of 30deg angled holes on a flat surface using the 3D Navier-Stokes solver Glenn-HT. A modification of the anti-vortex concept whereby the branched holes exit adjacent to the main hole has been studied computationally for blowing ratios of 1.0 and 2.0 and at density ratios of 1.0 and 2.0. This modified concept was selected because it has shown the most promise in recent experimental studies. The computational results show that the modified design improves the film cooling effectiveness relative to the round hole baseline and previous anti-vortex cases, in confirmation of the experimental studies.

Implications of the Large O VI Columns around Low-redshift L ∗ Galaxies

NASA Astrophysics Data System (ADS)

McQuinn, Matthew; Werk, Jessica K.

2018-01-01

Observations reveal massive amounts of O VI around star-forming L * galaxies, with covering fractions of near unity extending to the host halo’s virial radius. This O VI absorption is typically kinematically centered upon photoionized gas, with line widths that are suprathermal and kinematically offset from the galaxy. We discuss various scenarios and whether they could result in the observed phenomenology (cooling gas flows, boundary layers, shocks, virialized gas). If collisionally ionized, as we argue is most probable, the O VI observations require that the circumgalactic medium (CGM) of L * galaxies holds nearly all of the associated baryons within a virial radius (∼ {10}11 {M}ȯ ) and hosts massive flows of cooling gas with ≈ 30[{nT}/30 {{cm}}-3 {{K}}] {M}ȯ {{yr}}-1, which must be largely prevented from accreting onto the host galaxy. Cooling and feedback energetics considerations require 10< {nT}< 100 cm‑3 K for the warm and hot halo gases. We argue that virialized gas, boundary layers, hot winds, and shocks are unlikely to directly account for the bulk of the O VI. Furthermore, we show that there is a robust constraint on the number density of many of the photoionized ∼ {10}4 {{K}} absorption systems that yields upper bounds in the range n< (0.1-3) × {10}-3(Z/0.3) cm‑3, suggesting that the dominant pressure in some photoionized clouds is nonthermal. This constraint is in accordance with the low densities inferred from more complex photoionization modeling. The large amount of cooling gas that is inferred could re-form these clouds in a fraction of the halo dynamical time, and it requires much of the feedback energy available from supernovae to be dissipated in the CGM.

Unveiling Quasar Fueling through a Public Snapshot Survey of Quasar Host Environments

NASA Astrophysics Data System (ADS)

Johnson, Sean

2017-08-01

Feedback from quasars is thought to play a vital role in galaxy evolution, but the relationship between quasars and the halo gas that fuels star-formation on long timescales is not well constrained. Recent observations of the content of quasar host halos have found unusually high covering fractions of cool gas observed in absorption in background quasar spectra. The cool halo gas is strongly correlated with quasar luminosity and exceeds what is observed around non-AGN galaxies by factor of two. Together, these observations provide compelling evidence for a connection between AGN activity and halo gas on 20-200 kpc scales. The high covering fraction and correlation with quasar luminosity may be the result of debris from the galaxy mergers thought to trigger luminous quasars or the halo gas of satellites in gas-rich groups amenable to quasar feeding. If this is the case, then the cool gas observed in absorption will be correlated with signatures of recent galaxy interactions in the quasar host or satellites close to the background sightline. Here, we propose a snapshot imaging survey of z<1 quasars with available constraints on halo gas content to examine a possible correlation between cool halo gas and galaxy interaction signatures. Galaxy morphologies and faint tidal features at z 1 can only be observed with the high resolution imaging capabilities of HST due to the substantial flux in extended wings of AO point-spread functions. The images will be of significant archival value for studying the galaxy environments of quasars and for constraining gas flow models with multi-sightline halo gas studies of galaxies at lower redshift than the foreground & background quasars.

Quantum Cascade Laser Absorption Spectroscopy as a Plasma Diagnostic Tool: An Overview

PubMed Central

Welzel, Stefan; Hempel, Frank; Hübner, Marko; Lang, Norbert; Davies, Paul B.; Röpcke, Jürgen

2010-01-01

The recent availability of thermoelectrically cooled pulsed and continuous wave quantum and inter-band cascade lasers in the mid-infrared spectral region has led to significant improvements and new developments in chemical sensing techniques using in-situ laser absorption spectroscopy for plasma diagnostic purposes. The aim of this article is therefore two-fold: (i) to summarize the challenges which arise in the application of quantum cascade lasers in such environments, and, (ii) to provide an overview of recent spectroscopic results (encompassing cavity enhanced methods) obtained in different kinds of plasma used in both research and industry. PMID:22163581

Sodium leak detection system for liquid metal cooled nuclear reactors

DOEpatents

Modarres, Dariush

1991-01-01

A light source is projected across the gap between the containment vessel and the reactor vessel. The reflected light is then analyzed with an absorption spectrometer. The presence of any sodium vapor along the optical path results in a change of the optical transmissivity of the media. Since the absorption spectrum of sodium is well known, the light source is chosen such that the sensor is responsive only to the presence of sodium molecules. The optical sensor is designed to be small and require a minimum of amount of change to the reactor containment vessel.

Quantum cascade laser absorption spectroscopy as a plasma diagnostic tool: an overview.

PubMed

Welzel, Stefan; Hempel, Frank; Hübner, Marko; Lang, Norbert; Davies, Paul B; Röpcke, Jürgen

2010-01-01

The recent availability of thermoelectrically cooled pulsed and continuous wave quantum and inter-band cascade lasers in the mid-infrared spectral region has led to significant improvements and new developments in chemical sensing techniques using in-situ laser absorption spectroscopy for plasma diagnostic purposes. The aim of this article is therefore two-fold: (i) to summarize the challenges which arise in the application of quantum cascade lasers in such environments, and, (ii) to provide an overview of recent spectroscopic results (encompassing cavity enhanced methods) obtained in different kinds of plasma used in both research and industry.

Cooling quasiparticles in A 3C 60 fullerides by excitonic mid-infrared absorption

NASA Astrophysics Data System (ADS)

Nava, Andrea; Giannetti, Claudio; Georges, Antoine; Tosatti, Erio; Fabrizio, Michele

2018-02-01

Long after its discovery, superconductivity in alkali fullerides A3C60 still challenges conventional wisdom. The freshest inroad in such ever-surprising physics is the behaviour under intense infrared excitation. Signatures attributable to a transient superconducting state extending up to temperatures ten times higher than the equilibrium Tc ~ 20 K have been discovered in K3C60 after ultra-short pulsed infrared irradiation--an effect which still appears as remarkable as mysterious. Motivated by the observation that the phenomenon is observed in a broad pumping frequency range that coincides with the mid-infrared electronic absorption peak still of unclear origin, rather than to transverse optical phonons as has been proposed, we advance here a radically new mechanism. First, we argue that this broad absorption peak represents a `super-exciton' involving the promotion of one electron from the t1u half-filled state to a higher-energy empty t1g state, dramatically lowered in energy by the large dipole-dipole interaction acting in conjunction with the Jahn-Teller effect within the enormously degenerate manifold of (t1u)2(t1g)1 states. Both long-lived and entropy-rich because they are triplets, the infrared-induced excitons act as a sort of cooling mechanism that permits transient superconductive signals to persist up to much higher temperatures.

Solar heating, cooling, and domestic hot water system installed at Kaw Valley State Bank and Trust Company, Topeka, Kansas

NASA Technical Reports Server (NTRS)

1980-01-01

The building has approximately 5600 square feet of conditioned space. Solar energy was used for space heating, space cooling, and preheating domestic hot water (DHW). The solar energy system had an array of evacuated tube-type collectors with an area of 1068 square feet. A 50/50 solution of ethylene glycol and water was the transfer medium that delivered solar energy to a tube-in-shell heat exchanger that in turn delivered solar heated water to a 1100 gallon pressurized hot water storage tank. When solar energy was insufficient to satisfy the space heating and/or cooling demand, a natural gas-fired boiler provided auxiliary energy to the fan coil loops and/or the absorption chillers. Extracts from the site files, specification references, drawings, and installation, operation and maintenance instructions are presented.

Initial operation of a solar heating and cooling system in a full-scale solar building test facility

NASA Technical Reports Server (NTRS)

Knoll, R. H.; Miao, D.; Hamlet, I. L.; Jensen, R. N.

1976-01-01

The Solar Building Test Facility (SBTF) was constructed to advance the technology for heating and cooling of office buildings with solar energy. Its purposes are to (1) test system components which include high-performing collectors, (2) test the performance of a complete solar heating and cooling system, (3) investigate component interactions, and (4) investigate durability, maintenance and reliability of components. The SBTF consists of a 50,000 square foot office building modified to accept solar heated water for operation of an absorption air conditioner and for the baseboard heating system. A 12,666 square foot solar collector field with a 30,000 gallon storage tank provides the solar heated water. A description of the system and the collectors selected is printed along with the objectives, test approach, expected system performance, and some preliminary results.

High-resolution absorption cross section measurements of supersonic jet-cooled carbon monoxide between 92.5 and 97.4 nanometers

NASA Technical Reports Server (NTRS)

Yoshino, K.; Stark, G.; Esmond, J. R.; Smith, P. L.; Ito, K.; Matsui, T.

1995-01-01

High-resolution photoabsorption cross sections for eight CO bands, at wavelengths between 92.5 nm and 97.4 nm, have been measured in a supersonic jet-cooled source (approximately equals 20 K) at the Photon Factory synchrotron radiation facility. New integrated cross sections are reported for four bands between 92.5 nm and 94.2 nm. A low-temperature spectrum of the W(1)-X(0) band (95.6 nm), which was used to determine the absorbing CO column densities, is also presented. Additional jet-cooled cross section measurements were made on the L(0)-X(0), K(0)-X(0), and W(0)-X(0) bands (96.7-97.4 nm) which verify previously published results. A self-consistent set of band oscillator strengths is presented for the eight bands studied.

Investigation on the Acoustic Absorption of Flexible Micro-Perforated Panel with Ultra-Micro Perforations

NASA Astrophysics Data System (ADS)

Li, Guoxin; Tang, Xiaoning; Zhang, Xiaoxiao; Qian, Y. J.; Kong, Deyi

2017-11-01

Flexible micro-perforated panel has unique advantages in noise reduction due to its good flexibility compared with traditional rigid micro-perforated panel. In this paper, flexible micro-perforated panel was prepared by computer numerical control (CNC) milling machine. Three kinds of plastics including polyvinylchloride (PVC), polyethylene terephthalate (PET), and polyimide (PI) were taken as the matrix materials to prepare flexible micro-perforated panel. It has been found that flexible micro-perforated panel made of PET possessing good porosity and proper density, elastic modulus and poisson ratio exhibited the best acoustic absorption properties. The effects of various structural parameters including perforation diameter, perforation ratio, thickness and air gap have also been investigated, which would be helpful to the optimization of acoustic absorption properties.

Effects of Perforation on Rigid PU Foam Plates: Acoustic and Mechanical Properties

PubMed Central

Lin, Jia-Horng; Chuang, Yu-Chun; Li, Ting-Ting; Huang, Chen-Hung; Huang, Chien-Lin; Chen, Yueh-Sheng; Lou, Ching-Wen

2016-01-01

Factories today are equipped with diverse mechanical equipment in response to rapid technological and industrial developments. Industrial areas located near residential neighborhoods cause massive environmental problems. In particular, noise pollution results in physical and psychological discomfort, and is a seen as invisible and inevitable problem. Thus, noise reduction is a critical and urgent matter. In this study, rigid polyurethane (PU) foam plates undergo perforation using a tapping machine. The mechanical and acoustic properties of these perforated plates as related to perforation rate and perforation depth are evaluated in terms of compression strength, drop-weight impact strength, and sound absorption coefficient. Experimental results indicate that applying the perforation process endows the rigid PU foaming plates with greater load absorption and better sound absorption at medium and high frequencies. PMID:28774119

Effects of Perforation on Rigid PU Foam Plates: Acoustic and Mechanical Properties.

PubMed

Lin, Jia-Horng; Chuang, Yu-Chun; Li, Ting-Ting; Huang, Chen-Hung; Huang, Chien-Lin; Chen, Yueh-Sheng; Lou, Ching-Wen

2016-12-09

Factories today are equipped with diverse mechanical equipment in response to rapid technological and industrial developments. Industrial areas located near residential neighborhoods cause massive environmental problems. In particular, noise pollution results in physical and psychological discomfort, and is a seen as invisible and inevitable problem. Thus, noise reduction is a critical and urgent matter. In this study, rigid polyurethane (PU) foam plates undergo perforation using a tapping machine. The mechanical and acoustic properties of these perforated plates as related to perforation rate and perforation depth are evaluated in terms of compression strength, drop-weight impact strength, and sound absorption coefficient. Experimental results indicate that applying the perforation process endows the rigid PU foaming plates with greater load absorption and better sound absorption at medium and high frequencies.

Branched GAX cycle gas fired heat pump

DOE Office of Scientific and Technical Information (OSTI.GOV)

Erickson, D.C.; Anand, G.; Papar, R.A.

1996-12-31

GAX absorption heat pump cycles are characterized by the Generator Absorber Heat eXchange (GAX) between the high temperature end of the absorber and the low temperature end of the generator. The improved thermodynamic performance of the basic GAX cycle coupled with its mechanical simplicity has attracted substantial interest in using this cycle for gas-cooling. However, to be competitive in a cooling dominated market, the cycle has to achieve high cooling performance and also low installed cost. The Branched GAX (BGAX) cycle promises higher cooling performance using similar components as the basic GAX cycle and an additional solution pump. By increasingmore » the solution flow rate at the hot end of the absorber, the BGAX cycle makes more complete use of the temperature overlap. As a result, less external heat is supplied and higher COPs are obtained. A breadboard prototype of the BGAX cycle has been developed and is now operating. A novel thermosyphon cooled absorber eliminates the need for the outdoor hydronic loop, and reduces cost by 10%. Other component improvements yield another 10% cost reduction. The breadboard prototype has operated for more than 200 hours. Gas cooling COP = 0.87 has been consistently achieved at 30.6 C (87 F) ambient conditions. At the 35 C (95 F) ambient capacity rating condition, a cooling load of 4.5 refrigeration tons was achieved at a cycle COP = 0.95.« less

Comparison of different cooling rates for fibroblast and keratinocyte cryopreservation.

PubMed

Naaldijk, Yahaira; Friedrich-Stöckigt, Annett; Sethe, Sebastian; Stolzing, Alexandra

2016-10-01

Easy, cost-effective and reliable cryopreservation protocols are crucial for the successful and effective application of tissue engineering. Several different protocols are in use, but no comprehensive comparisons across different machine-based and manual methods have been made. Here, we compare the effects of different cooling rates on the post-thaw survival and proliferative capacity of two basic cell lines for skin tissue engineering fibroblasts and keratinocytes, cultured and frozen in suspension or as a monolayer. We demonstrate that effectiveness of cryopreservation cannot be reliably determined immediately after thawing: the results at this stage were not indicative of cell growth in culture 3 days post-thaw. Cryopreservation of fibroblasts in an adherent state greatly diminishes their subsequent growth potential. This was not observed when freezing in suspension. In keratinocytes, however, adherent freezing is as effective as freezing in suspension, which could lead to significant cost and labour savings in a tissue-engineering environment. The 'optimal' cryopreservation protocol depends on cell type and intended use. Where time, ease and cost are dominant factors, the direct freezing into a nitrogen tank (straight freeze) approach remains a viable method. The most effective solution across the board, as measured by viability 3 days post-thaw, was the commonly used, freezing container method. Where machine-controlled cryopreservation is deemed important for tissue-engineering Good Manufacturing Practice, we present results using a portfolio of different cooling rates, identifying the 'optimal' protocol depending on cell type and culture method. Copyright © 2013 John Wiley & Sons, Ltd. Copyright © 2013 John Wiley & Sons, Ltd.

Numerical modelling of heat and mass transfer in adsorption solar reactor of ammonia on active carbon

NASA Astrophysics Data System (ADS)

Aroudam, El. H.

In this paper, we present a modelling of the performance of a reactor of a solar cooling machine based carbon-ammonia activated bed. Hence, for a solar radiation, measured in the Energetic Laboratory of the Faculty of Sciences in Tetouan (northern Morocco), the proposed model computes the temperature distribution, the pressure and the ammonia concentration within the activated carbon bed. The Dubinin-Radushkevich formula is used to compute the ammonia concentration distribution and the daily cycled mass necessary to produce a cooling effect for an ideal machine. The reactor is heated at a maximum temperature during the day and cool at the night. A numerical simulation is carried out employing the recorded solar radiation data measured locally and the daily ambient temperature for the typical clear days. Initially the reactor is at ambient temperature, evaporating pressure; Pev=Pst(Tev=0 ∘C) and maintained at uniform concentration. It is heated successively until the threshold temperature corresponding to the condensing pressure; Pcond=Pst(Tam) (saturation pressure at ambient temperature; in the condenser) and until a maximum temperature at a constant pressure; Pcond. The cooling of the reactor is characterised by a fall of temperature to the minimal values at night corresponding to the end of a daily cycle. We use the mass balance equations as well as energy equation to describe heat and mass transfer inside the medium of three phases. A numerical solution of the obtained non linear equations system based on the implicit finite difference method allows to know all parameters characteristic of the thermodynamic cycle and consider principally the daily evolution of temperature, ammonia concentration for divers positions inside the reactor. The tube diameter of the reactor shows the dependence of the optimum value on meteorological parameters for 1 m2 of collector surface.

IRAS and the Boston University Arecibo Galactic H I Survey: A catalog of cloud properties

NASA Technical Reports Server (NTRS)

Bania, Thomas M.

1992-01-01

The Infrared Astronomy Satellite (IRAS) Galactic Plane Surface Brightness Images were used to identify infrared emission associated with cool, diffuse H I clouds detected by the Boston University-Arecibo Galactic H I Survey. These clouds are associated with galactic star clusters, H II regions, and molecular clouds. Using emission-absorption experiments toward galactic H II regions, we determined the H I properties of cool H I clouds seen in absorption against the thermal continuum, including their kinematic distances. Correlations were then made between IRAS sources and these H II regions, thus some of the spatial confusion associated with the IRAS fields near the galactic plane was resolved since the distances to these sources was known. Because we can also correlate the BU-Arecibo clouds with existing CO surveys, these results will allow us to determine the intrinsic properties of the gas (neutral and ionized atomic as well as molecular) and dust for interstellar clouds in the inner galaxy. For the IRAS-identified H II region sample, we have established the far infrared (FIR) luminosities and galactic distribution of these sources.

Theoretical modeling on the laser-induced phase deformation of liquid crystal optical phased shifter

NASA Astrophysics Data System (ADS)

Zhou, Zhuangqi; Wang, Xiangru; Zhuo, Rusheng; He, Xiaoxian; Wu, Liang; Wang, Xiaolin; Tan, Qinggui; Qiu, Qi

2018-03-01

To improve the working condition of liquid crystal phase shifter on incident laser power, a theoretical model on laser induced phase distortion is built on the physics of heat deposition and heat transfer. Four typical factors (absorption, heat sink structure, cooling fluid rate, and substrate) are analyzed to evaluate the influence of phase distortion when a relative high-power laser is pumped into the liquid crystal phase shifter. Flow rate of cooling fluid and heat sink structure are the most important two factors on improving the limit of incident laser power. Meanwhile, silicon wafer is suggested to replace the back glass contacting the heat sink, because of its higher heat transfer coefficient. If the device is fabricated on the conditions that: the total absorption is 5% and it has a strong heat sink structure with a flow rate of 0.01 m/s, when the incident laser power is 110W, the laser-induced phase deformation on the center is diminished to be less than 0.06, and the maximum temperature increase on the center is less than 1K degree.

Numerical and experimental analysis of a thin liquid film on a rotating disk related to development of a spacecraft absorption cooling system

NASA Technical Reports Server (NTRS)

Faghri, Amir; Swanson, Theodore D.

1989-01-01

The numerical and experimental analysis of a thin liquid film on a rotating and a stationary disk related to the development of an absorber unit for a high capacity spacecraft absorption cooling system, is described. The creation of artificial gravity by the use of a centrifugal field was focused upon in this report. Areas covered include: (1) One-dimensional computation of thin liquid film flows; (2) Experimental measurement of film height and visualization of flow; (3) Two-dimensional computation of the free surface flow of a thin liquid film using a pressure optimization method; (4) Computation of heat transfer in two-dimensional thin film flow; (5) Development of a new computational methodology for the free surface flows using a permeable wall; (6) Analysis of fluid flow and heat transfer in a thin film in the presence and absence of gravity; and (7) Comparison of theoretical prediction and experimental data. The basic phenomena related to fluid flow and heat transfer on rotating systems reported here can also be applied to other areas of space systems.

Intrinsic Lyα Profile Reconstructions of the MUSCLES Low-Mass Exoplanet Host Stars

NASA Astrophysics Data System (ADS)

Youngblood, Allison A.; France, Kevin; Loyd, R. O. Parke

2015-12-01

UV stellar radiation can significantly impact planetary atmospheres through heating and photochemistry, even regulating production of potential biomarkers. Cool stars emit the majority of their UV radiation in the form of emission lines, and the incident UV radiation on close-in habitable-zone planets is significant. Lyα (1215.67 Å) dominates the 912 - 3200 Å spectrum of cool stars, but strong absorption from the interstellar medium (ISM) makes direct observations of the intrinsic Lyα emission of even nearby stars challenging. The MUSCLES Hubble Space Telescope Treasury Survey (Measurements of the Ultraviolet Spectral Characteristics of Low-mass Exoplanetary Systems) has completed observations of 7 M and 4 K stars hosting exoplanets (d < 22 pc). We have reconstructed the intrinsic Lyα profiles using an MCMC technique and used the results to estimate the extreme ultraviolet (100 - 911 Å) spectrum. We also present empirical relations between Lyα and chromospheric UV metal lines, e.g., Mg II, for use when ISM absorption prevents direct measurement of Lyα. The spectra presented here will be made publicly available through MAST to support exoplanet atmosphere modeling.

Application of ultrasound in chicken breast during chilling by immersion promotes a fast and uniform cooling.

PubMed

Flores, Diego Rafael Martins; Brasil, Carla Cristina Bauermann; Campagnol, Paulo Cezar Bastianello; Jacob-Lopes, Eduardo; Zepka, Leila Queiroz; Wagner, Roger; Menezes, Cristiano Ragagnin; Barin, Juliano Smanioto; Flores, Erico Marlon Moraes; Cichoski, Alexandre José

2018-07-01

The initial objective of the study was to evaluate different operation modes (sweep and normal) and frequencies (25 and 130 kHz) of ultrasound in pre-chilling of breast chicken cylinders (BCC) immersed in water at 10 °C during 10 min. The second objective was to study the effect of the immersion time (5, 10, 15, 20, and 30 min) using the best operation mode and frequency obtained in the pre-chilling of the BCC in water at 10 °C. Pre-chilling was evaluated in both stages by infrared thermography, and the percentages of water absorption were determined in the second stage. The application of US at 130 kHz and normal operation mode provided a reduction of temperature on the surface of BBC higher (≈19.6%) than untreated samples. Also, compared to control, the US-treated samples in these conditions presented a more uniform cooling rate (≈22.3%) and higher water absorption (≈113%). Copyright © 2018 Elsevier Ltd. All rights reserved.

Overview of the observations of symbiotic stars

NASA Technical Reports Server (NTRS)

Viotti, Roberto

1993-01-01

The term Symbiotic stars commonly denotes variable stars whose optical spectra simultaneously present a cool absorption spectrum (typically TiO absorption bands) and emission lines of high ionization energy. This term is now used for the category of variable stars with composite spectrum. The main spectral features of these objects are: (1) the presence of the red continuum typical of a cool star, (2) the rich emission line spectrum, and (3) the UV excess, frequently with the Balmer continuum in emission. In addition to the peculiar spectrum, the very irregular photometric and spectroscopic variability is the major feature of the symbiotic stars. Moreover, the light curve is basic to identify the different phases of activity in a symbiotic star. The physical mechanisms that cause the symbiotic phenomenon and its variety are the focus of this paper. An astronomical phenomenon characterized by a composite stellar spectrum with two apparently conflicting features, and large variability has been observed. Our research set out to find the origin of this behavior and, in particular, to identify and measure the physical mechanism(s) responsible for the observed phenomena.

Using electron-tunneling refrigerators to cool electrons, membranes, and sensors

NASA Astrophysics Data System (ADS)

Miller, Nathan A.

Many cryogenic devices require temperatures near 100 mK for optimal performance, such as thin-film, superconducting detectors. Examples include the submillimeter SCUBA camera on the James Clerk Maxwell Telescope, high-resolution X-ray sensors for semiconductor defect analysis, and a planned satellite to search for polarization in the cosmic microwave background. The cost, size, and complexity of refrigerators used to reach 100 mK (dilution and adiabatic demagnetization refrigerators) are significant and alternative technologies are desirable. We demonstrate work on developing a new option for cooling detectors to 100 mK bath temperatures. Solid-state refrigerators based on Normal metal/Insulator/Superconductor (NIS) tunnel junctions can provide cooling from pumped 3He bath temperatures (˜300 mK) to 100 mK. The cooling mechanism is the preferential tunneling of the highest energy (hottest) electrons from the normal metal through the biased tunnel junctions into the superconductor. When NIS refrigerators are combined with a micro-machined membrane, both the electrons and phonons of the membrane can be cooled. We have developed NIS-cooled membranes with both large temperature reductions and large cooling powers. We have shown the first cooling of a bulk material by cooling a neutron transmutation doped (NTD) thermistor. The fabrication of NIS refrigerators can be integrated with existing detector technology. For the first time, we have successfully integrated NIS refrigerators with both mm-wave and X-ray detectors. In particular, we have cooled X-ray detectors by more than 100 mK and have achieved a resolution of <10 eV at 6 keV at a bath temperature 85 mK above the transition temperature of the detector. The use of integrated NIS refrigerators makes the remarkable performance of cryogenic detectors available from 300 mK platforms. We have also performed preliminary work towards building a general-purpose cooling platform for microelectronics devices on separate chips.

Influence of non-edible vegetable based oil as cutting fluid on chip, surface roughness and cutting force during drilling operation of Mild Steel

NASA Astrophysics Data System (ADS)

Susmitha, M.; Sharan, P.; Jyothi, P. N.

2016-09-01

Friction between work piece-cutting tool-chip generates heat in the machining zone. The heat generated reduces the tool life, increases surface roughness and decreases the dimensional sensitiveness of work material. This can be overcome by using cutting fluids during machining. They are used to provide lubrication and cooling effects between cutting tool and work piece and cutting tool and chip during machining operation. As a result, important benefits would be achieved such longer tool life, easy chip flow and higher machining quality in the machining processes. Non-edible vegetable oils have received considerable research attention in the last decades owing to their remarkable improved tribological characteristics and due to increasing attention to environmental issues, have driven the lubricant industry toward eco friendly products from renewable sources. In the present work, different non-edible vegetable oils are used as cutting fluid during drilling of Mild steel work piece. Non-edible vegetable oils, used are Karanja oil (Honge), Neem oil and blend of these two oils. The effect of these cutting fluids on chip formation, surface roughness and cutting force are investigated and the results obtained are compared with results obtained with petroleum based cutting fluids and dry conditions.

Compact Laser-Based Sensors for Monitoring and Control of Gas Turbine Combustors

NASA Technical Reports Server (NTRS)

Hanson, Ronald K.; Jeffries, Jay B.

2003-01-01

Research is reported on the development of sensors for gas turbine combustor applications that measure real-time gas temperature using near-infrared water vapor absorption and concentration in the combustor exhaust of trace quantities of pollutant NO and CO using mid-infrared absorption. Gas temperature is extracted from the relative absorption strength of two near-infrared transitions of water vapor. From a survey of the water vapor absorption spectrum, two overtone transitions near 1800 nm were selected that can be rapidly scanned in wavelength by injection current tuning a single DFB diode laser. From the ratio of the absorbances on these selected transitions, a path-integrated gas temperature can be extracted in near-real time. Demonstration measurements with this new temperature sensor showed that combustor instabilities could be identified in the power spectrum of the temperature versus time record. These results suggest that this strategy is extremely promising for gas turbine combustor control applications. Measurements of the concentration of NO and CO in the combustor exhaust are demonstrated with mid-infrared transitions using thermo-electrically cooled, quantum cascade lasers operating near 5.26 and 4.62 microns respectively. Measurements of NO are performed in an insulated exhaust duct of a C2H4-air flame at temperatures of approximately 600 K. CO measurements are performed above a rich H2-air flame seeded with CO2 and cooled with excess N2 to 1150 K. Using a balanced ratiometric detection technique a sensitivity of 0.36 ppm-m was achieved for NO and 0.21 ppm-m for CO. Comparisons between measured and predicted water-vapor and CO2 interference are discussed. The mid-infrared laser quantum cascade laser technology is in its infancy; however, these measurements demonstrate the potential for pollutant monitoring in exhaust gases with mid-IR laser absorption.

Optimization of concentrator photovoltaic solar cell performance through photonic engineering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harris, James

The goal of this program was to incorporate two new and innovative design concepts into the design and production of CPV cells that have near zero added cost, yet significantly increase the operational efficiency of CPV modules. The program focused developing luminescent coupling effects and radiative cooling layers to increase efficiency and suppress CPV module power losses due to spectral variations and heating. The major results of the program were: 1) The optics of three commercial refractive (Fresnel) concentrators were characterized and prevent application of radiative cooling concepts due to strong mid-IR absorption (4-12µm) required to effectively radiate blackbody radiationmore » from the cells and provide cooling. Investigation of alternative materials for the concentrator lenses produced only undesirable options—materials with reasonable mid-IR transmission for cooling only had about 30-40 visible transmission, thus reducing incident sunlight by >50%. While our investigation was somewhat limited, our work suggests that the only viable concentrator system that can incorporate radiative cooling utilizes reflective optics. 2) With limited ability to test high concentration CPV cells (requires outdoor testing), we acquired both semi-crystalline and crystalline Si cells and tested them in our outdoor facility and demonstrated 4°C cooling using a simple silica layer coating on the cells. 3) Characterizing Si cells in the IR associated with radiative cooling, we observed very significant near-IR absorption that increases the cell operating temperature by a similar amount, 4-5°C. By appropriate surface layer design, one can produce a layer that is highly reflective in the near-IR (1.5-4µm) and highly emissive in the mid-IR (5-15µm), thus reducing cell operational temperature by 10°C and increasing efficiency by ~1% absolute. The radiative cooling effect in c-Si solar cells might be further improved by providing a higher thermal conductive elastomer for securing the cover glass on top of the AR-coating. Since it was never imagined that the front surface would provide any cooling for solar cells, thermal conductivity of this elastomer was never a design consideration, but, improving the conductivity could decrease cell temperature by another 3-4°C. The combined effect could be an ~1.5% absolute increase in cell and module efficiency, a very significant improvement. 4) Developed a numerical model to explore dependence of luminescent coupling efficiency over a broad range of operating conditions. We developed a novel method and facility to experimentally measure the luminescent coupling that can be used to confirm the dependence of luminescent coupling on multi-junction cell design parameters.« less

MEMS Cantilever Sensor for THz Photoacoustic Chemical Sensing and Spectroscopy

DTIC Science & Technology

2013-12-26

meaning the detector didn’t have to be cryogenically cooled. Piezoresistive cantilever style sensor designs have been fabricated for wind and...made a two cantilever pizeoresistive wind speed sensor that utilized a Wheatstone bridge configuration. The designed cantilevers, etched out of...Murakami et al. in Japan fabricated diaphragm and cantilever PZT microphone sensors for anomaly detection in machines such as turbines or engines

Energy management system for a rotary machine and method therefor

DOEpatents

Bowman, Michael John; Sinha, Gautam; Sheldon, Karl Edward

2004-11-09

In energy management system is provided for a power generating device having a working fluid intake in which the energy management system comprises an electrical dissipation device coupled to the power generating device and a dissipation device cooling system configured to direct a portion of a working fluid to the electrical dissipation device so as to provide thermal control to the electrical dissipation device.

HST Detection of Extended Neutral Hydrogen in a Massive Elliptical at z = 0.4

NASA Astrophysics Data System (ADS)

Zahedy, Fakhri S.; Chen, Hsiao-Wen; Rauch, Michael; Zabludoff, Ann

2017-09-01

We report the first detection of extended neutral hydrogen (H I) gas in the interstellar medium (ISM) of a massive elliptical galaxy beyond z˜ 0. The observations utilize the doubly lensed images of QSO HE 0047-1756 at {z}{QSO}=1.676 as absorption-line probes of the ISM in the massive ({M}{star}≈ {10}11 {M}⊙ ) elliptical lens at z = 0.408, detecting gas at projected distances of d = 3.3 and 4.6 kpc on opposite sides of the lens. Using the Space Telescope Imaging Spectrograph, we obtain UV absorption spectra of the lensed QSO and identify a prominent flux discontinuity and associated absorption features matching the Lyman series transitions at z = 0.408 in both sightlines. The H I column density is log N({{H}} {{I}})=19.6{--}19.7 at both locations across the lens, comparable to what is seen in 21 cm images of nearby ellipticals. The H I gas kinematics are well-matched with the kinematics of the Fe II absorption complex revealed in ground-based echelle data, displaying a large velocity shear of ≈360 {\\text{km s}}-1 across the galaxy. We estimate an ISM Fe abundance of 0.3-0.4 solar at both locations. Including likely dust depletions increases the estimated Fe abundances to solar or supersolar, similar to those of the hot ISM and stars of nearby ellipticals. Assuming 100% covering fraction of this Fe-enriched gas, we infer a total Fe mass of {M}{cool}({Fe})˜ (5{--}8)× {10}4 {M}⊙ in the cool ISM of the massive elliptical lens, which is no more than 5% of the total Fe mass observed in the hot ISM.

The Extent of Chemically Enriched Gas around Star-forming Dwarf Galaxies

NASA Astrophysics Data System (ADS)

Johnson, Sean D.; Chen, Hsiao-Wen; Mulchaey, John S.; Schaye, Joop; Straka, Lorrie A.

2017-11-01

Supernova driven winds are often invoked to remove chemically enriched gas from dwarf galaxies to match their low observed metallicities. In such shallow potential wells, outflows may produce massive amounts of enriched halo gas (circumgalactic medium, CGM) and pollute the intergalactic medium (IGM). Here, we present a survey of the CGM and IGM around 18 star-forming field dwarfs with stellar masses of {log} {M}* /{M}⊙ ≈ 8{--}9 at z≈ 0.2. Eight of these have CGM probed by quasar absorption spectra at projected distances, d, less than that of the host virial radius, {R}{{h}}. Ten are probed in the surrounding IGM at d/{R}{{h}}=1{--}3. The absorption measurements include neutral hydrogen, the dominant silicon ions for diffuse cool gas (T ˜ 104 K; Si II, Si III, and Si IV), moderately ionized carbon (C IV), and highly ionized oxygen (O VI). Metal absorption from the CGM of the dwarfs is less common and ≈ 4× weaker compared to massive star-forming galaxies, though O VI absorption is still common. None of the dwarfs probed at d/{R}{{h}}=1{--}3 have definitive metal-line detections. Combining the available silicon ions, we estimate that the cool CGM of the dwarfs accounts for only 2%-6% of the expected silicon budget from the yields of supernovae associated with past star formation. The highly ionized O VI accounts for ≈8% of the oxygen budget. As O VI traces an ion with expected equilibrium ion fractions of ≲0.2, the highly ionized CGM may represent a significant metal reservoir even for dwarfs not expected to maintain gravitationally shock heated hot halos.

Radiation in fog: quantification of the impact on fog liquid water based on ground-based remote sensing

NASA Astrophysics Data System (ADS)

Wærsted, Eivind G.; Haeffelin, Martial; Dupont, Jean-Charles; Delanoë, Julien; Dubuisson, Philippe

2017-09-01

Radiative cooling and heating impact the liquid water balance of fog and therefore play an important role in determining their persistence or dissipation. We demonstrate that a quantitative analysis of the radiation-driven condensation and evaporation is possible in real time using ground-based remote sensing observations (cloud radar, ceilometer, microwave radiometer). Seven continental fog events in midlatitude winter are studied, and the radiative processes are further explored through sensitivity studies. The longwave (LW) radiative cooling of the fog is able to produce 40-70 g m-2 h-1 of liquid water by condensation when the fog liquid water path exceeds 30 g m-2 and there are no clouds above the fog, which corresponds to renewing the fog water in 0.5-2 h. The variability is related to fog temperature and atmospheric humidity, with warmer fog below a drier atmosphere producing more liquid water. The appearance of a cloud layer above the fog strongly reduces the LW cooling relative to a situation with no cloud above; the effect is strongest for a low cloud, when the reduction can reach 100 %. Consequently, the appearance of clouds above will perturb the liquid water balance in the fog and may therefore induce fog dissipation. Shortwave (SW) radiative heating by absorption by fog droplets is smaller than the LW cooling, but it can contribute significantly, inducing 10-15 g m-2 h-1 of evaporation in thick fog at (winter) midday. The absorption of SW radiation by unactivated aerosols inside the fog is likely less than 30 % of the SW absorption by the water droplets, in most cases. However, the aerosols may contribute more significantly if the air mass contains a high concentration of absorbing aerosols. The absorbed radiation at the surface can reach 40-120 W m-2 during the daytime depending on the fog thickness. As in situ measurements indicate that 20-40 % of this energy is transferred to the fog as sensible heat, this surface absorption can contribute significantly to heating and evaporation of the fog, up to 30 g m-2 h-1 for thin fog, even without correcting for the typical underestimation of turbulent heat fluxes by the eddy covariance method. Since the radiative processes depend mainly on the profiles of temperature, humidity and clouds, the results of this paper are not site specific and can be generalised to fog under different dynamic conditions and formation mechanisms, and the methodology should be applicable to warmer and moister climates as well. The retrieval of approximate emissivity of clouds above fog from cloud radar should be further developed.

Examinations for leak tightness of actively cooled components in ITER and fusion devices

NASA Astrophysics Data System (ADS)

Hirai, T.; Barabash, V.; Carrat, R.; Chappuis, Ph; Durocher, A.; Escourbiac, F.; Merola, M.; Raffray, R.; Worth, L.; Boscary, J.; Chantant, M.; Chuilon, B.; Guilhem, D.; Hatchressian, J.-C.; Hong, S. H.; Kim, K. M.; Masuzaki, S.; Mogaki, K.; Nicolai, D.; Wilson, D.; Yao, D.

2017-12-01

Any leak in one of the ITER actively cooled components would cause significant consequences for machine operations; therefore, the risk of leak must be minimized as much as possible. In this paper, the strategy of examination to ensure leak tightness of the ITER internal components (i.e. examination of base materials, vacuum boundary joints and final components) and the hydraulic parameters for ITER internal components are summarized. The experiences of component tests, especially hot helium leak tests in recent fusion devices, were reviewed and the parameters were discussed. Through these experiences, it was confirmed that the hot He leak test was effective to detect small leak paths which were not always possible to detect by volumetric examination due to limited spatial resolution.

Development of Compact Ozonizer with High Ozone Output by Pulsed Power

NASA Astrophysics Data System (ADS)

Tanaka, Fumiaki; Ueda, Satoru; Kouno, Kanako; Sakugawa, Takashi; Akiyama, Hidenori; Kinoshita, Youhei

Conventional ozonizer with a high ozone output using silent or surface discharges needs a cooling system and a dielectric barrier, and therefore becomes a large machine. A compact ozonizer without the cooling system and the dielectric barrier has been developed by using a pulsed power generated discharge. The wire to plane electrodes made of metal have been used. However, the ozone output was low. Here, a compact and high repetition rate pulsed power generator is used as an electric source of a compact ozonizer. The ozone output of 6.1 g/h and the ozone yield of 86 g/kWh are achieved at 500 pulses per second, input average power of 280 W and an air flow rate of 20 L/min.

Microelectromechanical System (MEMS) Device Being Developed for Active Cooling and Temperature Control

NASA Technical Reports Server (NTRS)

Beach, Duane E.

2003-01-01

High-capacity cooling options remain limited for many small-scale applications such as microelectronic components, miniature sensors, and microsystems. A microelectromechanical system (MEMS) using a Stirling thermodynamic cycle to provide cooling or heating directly to a thermally loaded surface is being developed at the NASA Glenn Research Center to meet this need. The device can be used strictly in the cooling mode or can be switched between cooling and heating modes in milliseconds for precise temperature control. Fabrication and assembly employ techniques routinely used in the semiconductor processing industry. Benefits of the MEMS cooler include scalability to fractions of a millimeter, modularity for increased capacity and staging to low temperatures, simple interfaces, limited failure modes, and minimal induced vibration. The MEMS cooler has potential applications across a broad range of industries such as the biomedical, computer, automotive, and aerospace industries. The basic capabilities it provides can be categorized into four key areas: 1) Extended environmental temperature range in harsh environments; 2) Lower operating temperatures for electronics and other components; 3) Precision spatial and temporal thermal control for temperature-sensitive devices; and 4) The enabling of microsystem devices that require active cooling and/or temperature control. The rapidly expanding capabilities of semiconductor processing in general, and microsystems packaging in particular, present a new opportunity to extend Stirling-cycle cooling to the MEMS domain. The comparatively high capacity and efficiency possible with a MEMS Stirling cooler provides a level of active cooling that is impossible at the microscale with current state-of-the-art techniques. The MEMS cooler technology builds on decades of research at Glenn on Stirling-cycle machines, and capitalizes on Glenn s emerging microsystems capabilities.

Research study demonstrates computer simulation can predict warpage and assist in its elimination

NASA Astrophysics Data System (ADS)

Glozer, G.; Post, S.; Ishii, K.

1994-10-01

Programs for predicting warpage in injection molded parts are relatively new. Commercial software for simulating the flow and cooling stages of injection molding have steadily gained acceptance; however, warpage software is not yet as readily accepted. This study focused on gaining an understanding of the predictive capabilities of the warpage software. The following aspects of this study were unique. (1) Quantitative results were found using a statistically designed set of experiments. (2) Comparisons between experimental and simulation results were made with parts produced in a well-instrumented and controlled injection molding machine. (3) The experimental parts were accurately measured on a coordinate measuring machine with a non-contact laser probe. (4) The effect of part geometry on warpage was investigated.

Optical levitation of 10-ng spheres with nano-g acceleration sensitivity

NASA Astrophysics Data System (ADS)

Monteiro, Fernando; Ghosh, Sumita; Fine, Adam Getzels; Moore, David C.

2017-12-01

We demonstrate optical levitation of SiO2 spheres with masses ranging from 0.1 to 30 ng. In high vacuum, we observe that the measured acceleration sensitivity improves for larger masses and obtain a sensitivity of 0.4 ×10-6g /√{Hz } for a 12-ng sphere, more than an order of magnitude better than previously reported for optically levitated masses. In addition, these techniques permit long integration times and a mean acceleration of (-0.7 ±2.4 [stat] ±0.2 [syst] ) ×10-9g is measured in 1.4 ×104 s. Spheres larger than 10 ng are found to lose mass in high vacuum where heating due to absorption of the trapping laser dominates radiative cooling. This absorption constrains the maximum size of spheres that can be levitated and allows a measurement of the absorption of the trapping light for the commercially available spheres tested here. Spheres consisting of material with lower absorption may allow larger objects to be optically levitated in high vacuum.

Pump absorption in coiled and twisted double-clad hexagonal fiber: effect of launching conditions and core location

NASA Astrophysics Data System (ADS)

Dalidet, Romain; Peterka, Pavel; Doya, Valérie; Aubrecht, Jan; Koška, Pavel

2018-02-01

Ever extending applications of fiber lasers require energy efficient, high-power, small footprint and reliable fiber lasers and laser wavelength versatility. To meet these demands, next generation of active fibers for high-power fiber lasers is coming out that will eventually offer tailored spectroscopic properties, high robustness and reduced cooling requirements and improved efficiency through tailored pump absorption. We report on numerical modelling of the efficiency of the pump absorption in double clad active fibers with hexagonal shape of the inner cladding cross section and rare-earth-doped core. We analyze both the effect of different radii of the spool on which the fiber is coiled and different fiber twisting rates. Two different launching conditions were investigated: the Gaussian input pump beam and a speckle pattern that mimics the output of the pump laser diode pigtail. We have found that by asymmetric position of the rare-earth-doped core we can significantly improve the pump absorption.

Research of heat transfer of staggered horizontal bundles of finned tubes at free air convection

NASA Astrophysics Data System (ADS)

Novozhilova, A. V.; Maryna, Z. G.; Samorodov, A. V.; Lvov, E. A.

2017-11-01

The study of free-convective processes is important because of the cooling problem in many machines and systems, where other ways of cooling are impossible or impractical. Natural convective processes are common in the steam turbine air condensers of electric power plants located within the city limits, in dry cooling towers of circulating water systems, in condensers cooled by air and water, in radiators cooling oil of power electric transformers, in emergency cooling systems of nuclear reactors, in solar power, as well as in air-cooling of power semiconductor energy converters. All this makes actual the synthesis of the results of theoretical and experimental research of free convection for heat exchangers with finned tube bundles. The results of the study of free-convection heat transfer for two-, three- and four-row staggered horizontal bundles of industrial bimetallic finned tubes with finning factor of 16.8 and equilateral tubes arrangement are presented. Cross and diagonal steps in the bundles are the same: 58; 61; 64; 70; 76; 86; 100 mm, which corresponds to the relative steps: 1.042; 1.096; 1.152; 1.258; 1.366; 1.545; 1.797. These steps are standardized for air coolers. An equation for calculating the free-convection heat transfer, taking into account the influence of geometrical parameters in the range of Rayleigh number from 30,000 to 350,000 with an average deviation of ± 4.8%, has been obtained. The relationship presented in the article allows designing a wide range of air coolers for various applications, working in the free convection modes.

Feasibility and operating costs of an air cycle for CCHP in a fast food restaurant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Perez-Blanco, Horacio; Vineyard, Edward

This work considers the possibilities of an air-based Brayton cycle to provide the power, heating and cooling needs of fast-food restaurants. A model of the cycle based on conventional turbomachinery loss coefficients is formulated. The heating, cooling and power capabilities of the cycle are extracted from simulation results. Power and thermal loads for restaurants in Knoxville, TN and in International Falls, MN, are considered. It is found that the cycle can meet the loads by setting speed and mass flow-rate apportionment between the power and cooling functional sections. The associated energy costs appear elevated when compared to the cost ofmore » operating individual components or a more conventional, absorption-based CHP system. Lastly, a first-order estimate of capital investments is provided. Suggestions for future work whereby the operational costs could be reduced are given in the conclusions.« less

Performance modeling of optical refrigerators

NASA Astrophysics Data System (ADS)

Mills, Gary; Mord, Allan

2006-02-01

Optical refrigeration using anti-Stokes fluorescence in solids has several advantages over more conventional techniques including low mass, low volume, low cost and no vibration. It also has the potential of allowing miniature cryocoolers on the scale of a few cubic centimeters. It has been the topic of analysis and experimental work by several organizations. In 2003, we demonstrated the first optical refrigerator. We have developed a comprehensive system-level performance model of optical refrigerators. Our current version models the refrigeration cycle based on the fluorescent material emission and absorption data at ambient and reduced temperature for the Ytterbium-ZBLAN glass (Yb:ZBLAN) cooling material. It also includes the heat transfer into the refrigerator cooling assembly due to radiation and conduction. In this paper, we report on modeling results which reveal the interplay between size, power input, and cooling load. This interplay results in practical size limitations using Yb:ZBLAN.

Feasibility and operating costs of an air cycle for CCHP in a fast food restaurant

DOE PAGES

Perez-Blanco, Horacio; Vineyard, Edward

2016-05-06

This work considers the possibilities of an air-based Brayton cycle to provide the power, heating and cooling needs of fast-food restaurants. A model of the cycle based on conventional turbomachinery loss coefficients is formulated. The heating, cooling and power capabilities of the cycle are extracted from simulation results. Power and thermal loads for restaurants in Knoxville, TN and in International Falls, MN, are considered. It is found that the cycle can meet the loads by setting speed and mass flow-rate apportionment between the power and cooling functional sections. The associated energy costs appear elevated when compared to the cost ofmore » operating individual components or a more conventional, absorption-based CHP system. Lastly, a first-order estimate of capital investments is provided. Suggestions for future work whereby the operational costs could be reduced are given in the conclusions.« less

Solar heating, cooling, and hot water systems installed at Richland, Washington

NASA Technical Reports Server (NTRS)

1979-01-01

The project described is part of the U. S. Department of Energy's solar demonstration program, and became operational in April 1978. The solar system uses 6,000 square feet of flat-plate liquid collectors in a closed loop to deliver solar energy through a liquid-liquid heat exchanger to the building heat-pump duct work or 9,000-gallon thermal energy storage tank. A 25-ton Arkla solar-driven absorption chiller provides the cooling, in conjunction with a 2,000 gallon chilled water storage tank and reflective ponds on three sides of the building surplus heat. A near-by building is essentially identical except for having conventional heat-pump heating and cooling, and can serve as an experimental control. An on-going public relations program was provided from the beginning of the program, and resulted in numerous visitors and tour groups.

Laser and Optical Subsystem for NASA's Cold Atom Laboratory

NASA Astrophysics Data System (ADS)

Kohel, James; Kellogg, James; Elliott, Ethan; Krutzik, Markus; Aveline, David; Thompson, Robert

2016-05-01

We describe the design and validation of the laser and optics subsystem for NASA's Cold Atom Laboratory (CAL), a multi-user facility being developed at NASA's Jet Propulsion Laboratory for studies of ultra-cold quantum gases in the microgravity environment of the International Space Station. Ultra-cold atoms will be generated in CAL by employing a combination of laser cooling techniques and evaporative cooling in a microchip-based magnetic trap. Laser cooling and absorption imaging detection of bosonic mixtures of 87 Rb and 39 K or 41 K will be accomplished using a high-power (up to 500 mW ex-fiber), frequency-agile dual wavelength (767 nm and 780 nm) laser and optical subsystem. The CAL laser and optical subsystem also includes the capability to generate high-power multi-frequency optical pulses at 784.87 nm to realize a dual-species Bragg atom interferometer. Currently at Humboldt-Universität zu Berlin.

X ray opacity in cluster cooling flows

NASA Technical Reports Server (NTRS)

Wise, Michael W.; Sarazin, Craig L.

1993-01-01

We have calculated the emergent x-ray properties for a set of spherically symmetric, steady-state cluster cooling flow models including the effects of radiative transfer. Opacity due to resonant x-ray lines, photoelectric absorption, and electron scattering have been included in these calculations, and homogeneous and inhomogeneous gas distributions were considered. The effects of photoionization opacity are small for both types of models. In contrast, resonant line optical depths can be quite high in both homogeneous and inhomogeneous models. The presence of turbulence in the gas can significantly lower the line opacity. We find that integrated x-ray spectra for the flow cooling now are only slightly affected by radiative transfer effects. However x-ray line surface brightness profiles can be dramatically affected by radiative transfer. Line profiles are also strongly affected by transfer effects. The combined effects of opacity and inflow cause many of the lines in optically thick models to be asymmetrical.

Variable X-ray Emission from FU Orionis

NASA Astrophysics Data System (ADS)

Skinner, Steve L.; Guedel, M.; Briggs, K. R.; Lamzin, S. A.; Sokal, K. R.

2009-05-01

FU Orionis is the prototype of a small but remarkable class of pre-main sequence stars ('FUors') that have undergone large optical outbursts thought to be linked to episodic accretion. FU Ori increased in optical brightness by about 6 mag in 1936-37 and is still in slow decline. Because of their high accretion rates, FUors are good candidates for exploring potential effects of accretion on X-ray emission. A recently completed survey of FUors with XMM-Newton detected X-rays from FU Ori and V1735 Cyg. We present new results from a sensitive 99 ksec (1.15 day) follow-up X-ray observation of FU Ori with Chandra. The Chandra ACIS-S CCD spectrum confirms the presence of a cool plasma component (kT < 1 keV) viewed under moderate absorption and a much hotter component (kT > 3 keV), viewed under high absorption, in accord with previous XMM results. The uninterrupted Chandra light curve shows that the hot component is slowly variable on a timescale of one day, but no variability is detected in the cool component. The slow variability and high plasma temperature point to a magnetic origin for the hot component, but other mechanisms (including accretion) may be responsible for the cool non-variable component. We will discuss these new results in the context of what is known about FU Ori from previous observations, including XMM (Skinner et al. 2006, ApJ, 643, 995) and HST (Kravtsova et al. 2007, Ast. Ltrs., 33, 755).

Pyrometer mount for a closed-circuit thermal medium cooled gas turbine

DOEpatents

Jones, Raymond Joseph; Kirkpatrick, Francis Lawrence; Burns, James Lee; Fulton, John Robert

2002-01-01

A steam-cooled second-stage nozzle segment has an outer band and an outer cover defining a plenum therebetween for receiving cooling steam for flow through the nozzles to the inner band and cover therefor and return flow through the nozzles. To measure the temperature of the buckets of the stage forwardly of the nozzle stage, a pyrometer boss is electron beam-welded in an opening through the outer band and TIG-welded to the outer cover plate. By machining a hole through the boss and seating a linearly extending tube in the boss, a line of sight between a pyrometer mounted on the turbine frame and the buckets is provided whereby the temperature of the buckets can be ascertained. The welding of the boss to the outer band and outer cover enables steam flow through the plenum without leakage, while providing a line of sight through the outer cover and outer band to measure bucket temperature.

Dynamical Study of Femtosecond-Laser-Ablated Liquid-Aluminum Nanoparticles Using Spatiotemporally Resolved X-Ray-Absorption Fine-Structure Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oguri, Katsuya; Okano, Yasuaki; Nishikawa, Tadashi

2007-10-19

We study the temperature evolution of aluminum nanoparticles generated by femtosecond laser ablation with spatiotemporally resolved x-ray-absorption fine-structure spectroscopy. We successfully identify the nanoparticles based on the L-edge absorption fine structure of the ablation plume in combination with the dependence of the edge structure on the irradiation intensity and the expansion velocity of the plume. In particular, we show that the lattice temperature of the nanoparticles is estimated from the L-edge slope, and that its spatial dependence reflects the cooling of the nanoparticles during plume expansion. The results reveal that the emitted nanoparticles travel in a vacuum as a condensedmore » liquid phase with a lattice temperature of about 2500 to 4200 K in the early stage of plume expansion.« less

Design, fabrication, and operation of a test rig for high-speed tapered-roller bearings

NASA Technical Reports Server (NTRS)

Signer, H. R.

1974-01-01

A tapered-roller bearing test machine was designed, fabricated and successfully operated at speeds to 20,000 rpm. Infinitely variable radial loads to 26,690 N (6,000 lbs.) and thrust loads to 53,380 N (12,000 lbs.) can be applied to test bearings. The machine instrumentation proved to have the accuracy and reliability required for parametric bearing performance testing and has the capability of monitoring all programmed test parameters at continuous operation during life testing. This system automatically shuts down a test if any important test parameter deviates from the programmed conditions, or if a bearing failure occurs. A lubrication system was developed as an integral part of the machine, capable of lubricating test bearings by external jets and by means of passages feeding through the spindle and bearing rings into the critical internal bearing surfaces. In addition, provisions were made for controlled oil cooling of inner and outer rings to effect the type of bearing thermal management that is required when testing at high speeds.

Strength computation of forged parts taking into account strain hardening and damage

NASA Astrophysics Data System (ADS)

Cristescu, Michel L.

2004-06-01

Modern non-linear simulation software, such as FORGE 3 (registered trade mark of TRANSVALOR), are able to compute the residual stresses, the strain hardening and the damage during the forging process. A thermally dependent elasto-visco-plastic law is used to simulate the behavior of the material of the hot forged piece. A modified Lemaitre law coupled with elasticiy, plasticity and thermic is used to simulate the damage. After the simulation of the different steps of the forging process, the part is cooled and then virtually machined, in order to obtain the finished part. An elastic computation is then performed to equilibrate the residual stresses, so that we obtain the true geometry of the finished part after machining. The response of the part to the loadings it will sustain during it's life is then computed, taking into account the residual stresses, the strain hardening and the damage that occur during forging. This process is illustrated by the forging, virtual machining and stress analysis of an aluminium wheel hub.

Sub-diffraction limit laser ablation via multiple exposures using a digital micromirror device.

PubMed

Heath, Daniel J; Grant-Jacob, James A; Feinaeugle, Matthias; Mills, Ben; Eason, Robert W

2017-08-01

We present the use of digital micromirror devices as variable illumination masks for pitch-splitting multiple exposures to laser machine the surfaces of materials. Ultrafast laser pulses of length 150 fs and 800 nm central wavelength were used for the sequential machining of contiguous patterns on the surface of samples in order to build up complex structures with sub-diffraction limit features. Machined patterns of tens to hundreds of micrometers in lateral dimensions with feature separations as low as 270 nm were produced in electroless nickel on an optical setup diffraction limited to 727 nm, showing a reduction factor below the Abbe diffraction limit of ∼2.7×. This was compared to similar patterns in a photoresist optimized for two-photon absorption, which showed a reduction factor of only 2×, demonstrating that multiple exposures via ablation can produce a greater resolution enhancement than via two-photon polymerization.

Moderate temperature control technology for a lunar base

NASA Technical Reports Server (NTRS)

Swanson, Theodore D.; Sridhar, K. R.; Gottmann, Matthias

1993-01-01

A parametric analysis is performed to compare different heat pump based thermal control systems for a Lunar Base. Rankine cycle and absorption cycle heat pumps are compared and optimized for a 100 kW cooling load. Variables include the use or lack of an interface heat exchanger, and different operating fluids. Optimization of system mass to radiator rejection temperature is performed. The results indicate a relatively small sensitivity of Rankine cycle system mass to these variables, with optimized system masses of about 6000 kg for the 100 kW thermal load. It is quantitaively demonstrated that absorption based systems are not mass competitive with Rankine systems.

Infrared spectroscopic measurements relevant to atmospheric remote sensing

NASA Technical Reports Server (NTRS)

Varanasi, Prasad; Gopalan, Arun

1993-01-01

SF6 is a synthetic chemical which is used in many industrial applications and as a meteorological tracer. This paper describes determinations of spectral absorption coefficients k-nu of SF6 measured in the central Q-branches of the nu(3)-fundamental at 947/cm at various temperature-pressure combinations representing tangent heights in solar-occultation experiments or layers in the atmosphere. Spectral data were also obtained for C2H4 and NH3 fundamental bands. Measurements were made with the Doppler-limited spectral resolution of a tunable diode laser spectrometer with a cryogenically cooled absorption cell, described by Varanasi and Chudamani (1992).

A case of nosocomial Legionella pneumonia associated with a contaminated hospital cooling tower.

PubMed

Osawa, Kayo; Shigemura, Katsumi; Abe, Yasuhisa; Jikimoto, Takumi; Yoshida, Hiroyuki; Fujisawa, Masato; Arakawa, Soichi

2014-01-01

We report the epidemiological investigation of a nosocomial pneumonia case due to Legionella pneumophila linked to a contaminated hospital cooling tower in an immune-compromised patient. A 73-year-old female patient was diagnosed with nosocomial Legionella pneumonia proven by a culture of L. pneumophila serogroup 1 from bronchoalveolar lavage fluid. Two strains isolated from the patient and two strains isolated from two cooling towers were found to be identical using repetitive-sequence-based-PCR with a 95% probability. This Legionella pneumonia case might be caused by aerosol from cooling towers on the roof of the hospital building which was contaminated by L. pneumophila. We increased up the temperature of hot water supply appropriately for prevention of Legionella breeding in an environment of patients' living. On the other hand, as the maintenance of cooling tower, we increased the frequency of Legionella culture tests from twice a year to three times a year. In addition, we introduced an automated disinfectants insertion machine and added one antiseptic reagent (BALSTER ST-40 N, Tohzai Chemical Industry Co., Ltd., Kawasaki, Japan) after this Legionella disease, and thereafter, we have no additional cases of Legionella disease or detection of Legionella spp. from the cooling tower or hot water supply. This case demonstrates the importance of detecting the infection source and carrying out environmental maintenance in cooperation with the infection control team. Copyright © 2013 Japanese Society of Chemotherapy and the Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Chemical Characterization of Simulated Boiling Water Reactor Coolant

DTIC Science & Technology

1990-05-01

33 Table 3. 1: BCCL Sample Block Design Calculations ........................................... 45 Table 5.1: Gas Absorption...cover gas . The cool, degassed pure water is pumped through a regenerative heat exchanger and then through an electric feedwater heater. The feedwater is...POINTS DWCMRHEAT DOWNOMER---EXCHANGER CHEMICAL GAHP INJECTIOIN PUMP SYSTEM COIVER GAS IN-CLIRE SECTION CAGN TANK RECOMBINER! ______ DEMINERALIZER (Cic

Limiting the Temperatures in Naturally Ventilated Buildings in Warm Climates. Building Research Establishment Current Paper 7/74.

ERIC Educational Resources Information Center

Petherbridge, P.

Formulas used in the calculation of cooling loads and indoor temperatures are employed to demonstrate the influence of various building parameters--such as thermal transmittance (U-value), solar absorptivity, and thermal storage--on the indoor thermal environment. The analysis leads to guidance on ways of limiting temperatures in naturally…

Optimizing cutting conditions on sustainable machining of aluminum alloy to minimize power consumption

NASA Astrophysics Data System (ADS)

Nur, Rusdi; Suyuti, Muhammad Arsyad; Susanto, Tri Agus

2017-06-01

Aluminum is widely utilized in the industrial sector. There are several advantages of aluminum, i.e. good flexibility and formability, high corrosion resistance and electrical conductivity, and high heat. Despite of these characteristics, however, pure aluminum is rarely used because of its lacks of strength. Thus, most of the aluminum used in the industrial sectors was in the form of alloy form. Sustainable machining can be considered to link with the transformation of input materials and energy/power demand into finished goods. Machining processes are responsible for environmental effects accepting to their power consumption. The cutting conditions have been optimized to minimize the cutting power, which is the power consumed for cutting. This paper presents an experimental study of sustainable machining of Al-11%Si base alloy that was operated without any cooling system to assess the capacity in reducing power consumption. The cutting force was measured and the cutting power was calculated. Both of cutting force and cutting power were analyzed and modeled by using the central composite design (CCD). The result of this study indicated that the cutting speed has an effect on machining performance and that optimum cutting conditions have to be determined, while sustainable machining can be followed in terms of minimizing power consumption and cutting force. The model developed from this study can be used for evaluation process and optimization to determine optimal cutting conditions for the performance of the whole process.

Single-molecule electronics: Cooling individual vibrational modes by the tunneling current.

PubMed

Lykkebo, Jacob; Romano, Giuseppe; Gagliardi, Alessio; Pecchia, Alessandro; Solomon, Gemma C

2016-03-21

Electronic devices composed of single molecules constitute the ultimate limit in the continued downscaling of electronic components. A key challenge for single-molecule electronics is to control the temperature of these junctions. Controlling heating and cooling effects in individual vibrational modes can, in principle, be utilized to increase stability of single-molecule junctions under bias, to pump energy into particular vibrational modes to perform current-induced reactions, or to increase the resolution in inelastic electron tunneling spectroscopy by controlling the life-times of phonons in a molecule by suppressing absorption and external dissipation processes. Under bias the current and the molecule exchange energy, which typically results in heating of the molecule. However, the opposite process is also possible, where energy is extracted from the molecule by the tunneling current. Designing a molecular "heat sink" where a particular vibrational mode funnels heat out of the molecule and into the leads would be very desirable. It is even possible to imagine how the vibrational energy of the other vibrational modes could be funneled into the "cooling mode," given the right molecular design. Previous efforts to understand heating and cooling mechanisms in single molecule junctions have primarily been concerned with small models, where it is unclear which molecular systems they correspond to. In this paper, our focus is on suppressing heating and obtaining current-induced cooling in certain vibrational modes. Strategies for cooling vibrational modes in single-molecule junctions are presented, together with atomistic calculations based on those strategies. Cooling and reduced heating are observed for two different cooling schemes in calculations of atomistic single-molecule junctions.

Thermal analysis of regenerative-cooled pylon in multi-mode rocket based combined cycle engine

NASA Astrophysics Data System (ADS)

Yan, Dekun; He, Guoqiang; Li, Wenqiang; Zhang, Duo; Qin, Fei

2018-07-01

Combining pylon injector with rocket is an effective method to achieve efficient mixing and combustion in the RBCC engine. This study designs a fuel pylon with active cooling structure, and numerically investigates the coupled heat transfer between active cooling process in the pylon and combustion in the combustor in different modes. Effect of the chemical reaction of the fuel on the flow, heat transfer and physical characteristics is also discussed. The numerical results present a good agreement with the experimental data. Results indicate that drastic supplementary combustion caused by rocket gas and secondary combustion caused by the fuel injection from the pylon result in severe thermal load on the pylon. Although regenerative cooling without cracking can reduce pylon's temperature below the allowable limit, a high-temperature area appears in the middle and nail section of the pylon due to the coolant's insufficient convective heat transfer coefficient. Comparatively, endothermic cracking can provide extra chemical heat sink for the coolant and low velocity contributes to prolong the reaction time to increase the heat absorption from chemical reaction, which further lowers and unifies the pylon surface temperature.

Slow hot carrier cooling in cesium lead iodide perovskites

NASA Astrophysics Data System (ADS)

Shen, Qing; Ripolles, Teresa S.; Even, Jacky; Ogomi, Yuhei; Nishinaka, Koji; Izuishi, Takuya; Nakazawa, Naoki; Zhang, Yaohong; Ding, Chao; Liu, Feng; Toyoda, Taro; Yoshino, Kenji; Minemoto, Takashi; Katayama, Kenji; Hayase, Shuzi

2017-10-01

Lead halide perovskites are attracting a great deal of interest for optoelectronic applications such as solar cells, LEDs, and lasers because of their unique properties. In solar cells, heat dissipation by hot carriers results in a major energy loss channel responsible for the Shockley-Queisser efficiency limit. Hot carrier solar cells offer the possibility to overcome this limit and achieve energy conversion efficiency as high as 66% by extracting hot carriers. Therefore, fundamental studies on hot carrier relaxation dynamics in lead halide perovskites are important. Here, we elucidated the hot carrier cooling dynamics in all-inorganic cesium lead iodide (CsPbI3) perovskite using transient absorption spectroscopy. We observe that the hot carrier cooling rate in CsPbI3 decreases as the fluence of the pump light increases and the cooling is as slow as a few 10 ps when the photoexcited carrier density is 7 × 1018 cm-3, which is attributed to phonon bottleneck for high photoexcited carrier densities. Our findings suggest that CsPbI3 has a potential for hot carrier solar cell applications.

Energy and environmental evaluation of combined cooling heating and power system

NASA Astrophysics Data System (ADS)

Bugaj, Andrzej

2017-11-01

The paper addresses issues involving problems of implementing combined cooling, heating and power (CCHP) system to industrial facility with well-defined demand profiles of cooling, heating and electricity. The application of CCHP system in this particular industrial facility is being evaluated by comparison with the reference system that consists of three conventional methods of energy supply: (a) electricity from external grid, (b) heat from gas-fired boilers and (c) cooling from vapour compression chillers run by electricity from the grid. The CCHP system scenario is based on the combined heat and power (CHP) plant with gas turbine-compressor arrangement and water/lithium bromide absorption chiller of a single-effect type. Those two scenarios are analysed in terms of annual primary energy usage as well as emissions of CO2. The results of the analysis show an extent of primary energy savings of the CCHP system in comparison with the reference system. Furthermore, the environmental impact of the CCHP usage, in the form of greenhouse gases emission reductions, compares quite favourably with the reference conventional option.

Probing Buffer-Gas Cooled Molecules with Direct Frequency Comb Spectroscopy in the Mid-Infrrared

NASA Astrophysics Data System (ADS)

Spaun, Ben; Changala, Bryan; Bjork, Bryce J.; Heckl, Oliver H.; Patterson, David; Doyle, John M.; Ye, Jun

2015-06-01

We present the first demonstration of cavity-enhanced direct frequency comb spectroscopy on buffer-gas cooled molecules.By coupling a mid-infrared frequency comb to a high-finesse cavity surrounding a helium buffer-gas chamber, we can gather rotationally resolved absorption spectra with high sensitivity over a broad wavelength region. The measured ˜10 K rotational and translational temperatures of buffer-gas cooled molecules drastically simplify the observed spectra, compared to those of room temperature molecules, and allow for high spectral resolution limited only by Doppler broadening (10-100 MHz). Our system allows for the extension of high-resolution spectroscopy to larger molecules, enabling detailed analysis of molecular structure and dynamics, while taking full advantage of the powerful optical properties of frequency combs. A. Foltynowicz et al. Cavity-enhanced optical frequency comb spectroscopy in the mid-infrared application to trace detection of hydrogen peroxide. Applied Physics B, vol. 110, pp. 163-175, 2013. {D. Patterson and J. M. Doyle. Cooling molecules in a cell for FTMW spectroscopy. Molecular Physics 110, 1757-1766, 2012

The classification of the patients with pulmonary diseases using breath air samples spectral analysis

NASA Astrophysics Data System (ADS)

Kistenev, Yury V.; Borisov, Alexey V.; Kuzmin, Dmitry A.; Bulanova, Anna A.

2016-08-01

Technique of exhaled breath sampling is discussed. The procedure of wavelength auto-calibration is proposed and tested. Comparison of the experimental data with the model absorption spectra of 5% CO2 is conducted. The classification results of three study groups obtained by using support vector machine and principal component analysis methods are presented.

Identification of New Potential Scientific and Technology Areas for DoD Application. Summary of Activities

DTIC Science & Technology

1986-07-31

designer will be able to more rapid- ly assemble a total software package from perfected modules that can be easily de - bugged or replaced with more...antinuclear interactions e. gravitational effects of antimatter 2. possible machine parameters and lattice design 3. electron and stochastic cooling needs 4...implementation, reliability requirements; development of design environments and of experimental methodology; technology transfer methods from

Verifying Dissolution Of Wax From Hardware Surfaces

NASA Technical Reports Server (NTRS)

Montoya, Benjamina G.

1995-01-01

Wax removed by cleaning solvent revealed by cooling solution with liquid nitrogen. Such improved procedure and test needed in case of hardware that must be protected by wax during machining or plating but required to be free of wax during subsequent use. Improved cleaning procedure and test take less than 5 minutes. Does not require special skill or equipment and performs at cleaning site. In addition, enables recovery of all cleaning solvent.

Superconducting-electromagnetic hybrid bearing using YBCO bulk blocks for passive axial levitation

NASA Astrophysics Data System (ADS)

Nicolsky, R.; de Andrade, R., Jr.; Ripper, A.; David, D. F. B.; Santisteban, J. A.; Stephan, R. M.; Gawalek, W.; Habisreuther, T.; Strasser, T.

2000-06-01

A superconducting/electromagnetic hybrid bearing has been designed using active radial electromagnetic positioning and a superconducting passive axial levitator. This bearing has been tested for an induction machine with a vertical shaft. The prototype was conceived as a four-pole, two-phase induction machine using specially designed stator windings for delivering torque and radial positioning simultaneously. The radial bearing uses four eddy-current sensors, displaced 90° from each other, for measuring the shaft position and a PID control system for feeding back the currents. The stator windings have been adapted from the ones of a standard induction motor. The superconducting axial bearing has been assembled with commercial NdFeB permanent magnets and a set of seven top-seeded-melt-textured YBCO large-grain cylindrical blocks. The bearing set-up was previously simulated by a finite element method for different permanent magnet-superconductor block configurations. The stiffness of the superconducting axial bearing has been investigated by measuring by a dynamic method the vertical and transversal elastic constants for different field cooling processes. The resulting elastic constants show a linear dependence on the air gap, i.e. the clearance between the permanent magnet assembly and the set of superconducting large-grain blocks, which is dependent on cooling distance.

First-principles calculations of niobium hydride formation in superconducting radio-frequency cavities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ford, Denise C.; Cooley, Lance D.; Seidman, David N.

Niobium hydride is suspected to be a major contributor to degradation of the quality factor of niobium superconducting radio-frequency (SRF) cavities. In this study, we connect the fundamental properties of hydrogen in niobium to SRF cavity performance and processing. We modeled several of the niobium hydride phases relevant to SRF cavities and present their thermodynamic, electronic, and geometric properties determined from calculations based on density-functional theory. We find that the absorption of hydrogen from the gas phase into niobium is exothermic and hydrogen becomes somewhat anionic. The absorption of hydrogen by niobium lattice vacancies is strongly preferred over absorption intomore » interstitial sites. A single vacancy can accommodate six hydrogen atoms in the symmetrically equivalent lowest-energy sites and additional hydrogen in the nearby interstitial sites affected by the strain field: this indicates that a vacancy can serve as a nucleation center for hydride phase formation. Small hydride precipitates may then occur near lattice vacancies upon cooling. Vacancy clusters and extended defects should also be enriched in hydrogen, potentially resulting in extended hydride phase regions upon cooling. We also assess the phase changes in the niobium-hydrogen system based on charge transfer between niobium and hydrogen, the strain field associated with interstitial hydrogen, and the geometry of the hydride phases. The results of this study stress the importance of not only the hydrogen content in niobium, but also the recovery state of niobium for the performance of SRF cavities.« less

Triple loop heat exchanger for an absorption refrigeration system

DOEpatents

Reimann, Robert C.

1984-01-01

A triple loop heat exchanger for an absorption refrigeration system is disclosed. The triple loop heat exchanger comprises portions of a strong solution line for conducting relatively hot, strong solution from a generator to a solution heat exchanger of the absorption refrigeration system, conduit means for conducting relatively cool, weak solution from the solution heat exchanger to the generator, and a bypass system for conducting strong solution from the generator around the strong solution line and around the solution heat exchanger to an absorber of the refrigeration system when strong solution builds up in the generator to an undesirable level. The strong solution line and the conduit means are in heat exchange relationship with each other in the triple loop heat exchanger so that, during normal operation of the refrigeration system, heat is exchanged between the relatively hot, strong solution flowing through the strong solution line and the relatively cool, weak solution flowing through the conduit means. Also, the strong solution line and the bypass system are in heat exchange relationship in the triple loop heat exchanger so that if the normal flow path of relatively hot, strong solution flowing from the generator to an absorber is blocked, then this relatively, hot strong solution which will then be flowing through the bypass system in the triple loop heat exchanger, is brought into heat exchange relationship with any strong solution which may have solidified in the strong solution line in the triple loop heat exchanger to thereby aid in desolidifying any such solidified strong solution.

Subsurface wrinkle removal by laser treatment in combination with dynamic cooling

NASA Astrophysics Data System (ADS)

Paithankar, Dilip Y.; Hsia, James C.; Ross, E. V.

2000-05-01

Compared to traditional CO2 or Er:YAG laser resurfacing, sub-surface thermal injury to stimulate skin remodeling for the removal of wrinkles is attractive due to the lower morbidity associated with epidermal preservation. We have developed a technique that thermally damages dermal collagen while preserving the epidermis by a combination of infra-red laser irradiation and dynamic cooling of skin. Wound healing response to the thermal denaturation of collagen may trigger synthesis of fresh collagen and result in restoration of a more youthful appearance. The laser wavelength is chosen so as to thermally injure dermis in a narrow band at depths of 150 to 500 microns from the surface of the skin. The epidermis is preserved by a Candela dynamic cooling device (DCDTM) cryogen spray. Three-dimensional Monte Carlo calculations have been done to calculate the light distribution within tissue while taking into account light absorption and scattering. This light distribution has been used to calculate heat generation within tissue. Heat transfer calculations have been done while taking into consideration the cryogen cooling. The resulting temperature profiles have been used to suggest heating and cooling parameters. Freshly excised ex vivo pig skin was irradiated with laser and DCD at these heating and cooling parameters. Histological evaluation of the biopsies has shown that it is possible to spare the epidermis while thermally denaturing the dermal collagen. The modeling and histology results are discussed.

The Next Era: Deep Learning in Pharmaceutical Research.

PubMed

Ekins, Sean

2016-11-01

Over the past decade we have witnessed the increasing sophistication of machine learning algorithms applied in daily use from internet searches, voice recognition, social network software to machine vision software in cameras, phones, robots and self-driving cars. Pharmaceutical research has also seen its fair share of machine learning developments. For example, applying such methods to mine the growing datasets that are created in drug discovery not only enables us to learn from the past but to predict a molecule's properties and behavior in future. The latest machine learning algorithm garnering significant attention is deep learning, which is an artificial neural network with multiple hidden layers. Publications over the last 3 years suggest that this algorithm may have advantages over previous machine learning methods and offer a slight but discernable edge in predictive performance. The time has come for a balanced review of this technique but also to apply machine learning methods such as deep learning across a wider array of endpoints relevant to pharmaceutical research for which the datasets are growing such as physicochemical property prediction, formulation prediction, absorption, distribution, metabolism, excretion and toxicity (ADME/Tox), target prediction and skin permeation, etc. We also show that there are many potential applications of deep learning beyond cheminformatics. It will be important to perform prospective testing (which has been carried out rarely to date) in order to convince skeptics that there will be benefits from investing in this technique.

Effects of Controlled Cooling-Induced Ferrite-Pearlite Microstructure on the Cold Forgeability of XC45 Steel

NASA Astrophysics Data System (ADS)

Hu, Chengliang; Chen, Lunqiang; Zhao, Zhen; Gong, Aijun; Shi, Weibing

2018-05-01

The combination of hot/warm and cold forging with an intermediate controlled cooling process is a promising approach to saving costs in the manufacture of automobile parts. In this work, the effects of the ferrite-pearlite microstructure, which formed after controlled cooling, on the cold forgeability of a medium-carbon steel were investigated. Different specimens for both normal and notched tensile tests were directly heated to high temperature and then cooled down at different cooling rates, producing different ferrite volume fractions, ranging from 6.69 to 40.53%, in the ferrite-pearlite microstructure. The yield strength, ultimate tensile strength, elongation rate, percentage reduction of area, and fracture strain were measured by tensile testing. The yield strength, indicating deformation resistance, and fracture strain, indicating formability, were used to evaluate the cold forgeability. As the ferrite volume fraction increased, the cold forgeability of the dual-phase ferritic-pearlitic steel improved. A quantitatively relationship between the ferrite volume fraction and the evaluation indexes of cold forgeability for XC45 steel was obtained from the test data. To validate the mathematical relationship, different tensile specimens machined from real hot-forged workpieces were tested. There was good agreement between the predicted and measured values. Our predictions from the relationship for cold forgeability had an absolute error less than 5%, which is acceptable for industrial applications and will help to guide the design of combined forging processes.

Pinned orbital moments in uncompensated antiferromagnetic Co doped ZnO

NASA Astrophysics Data System (ADS)

Buchner, Martin; Henne, Bastian; Ney, Verena; Lumetzberger, Julia; Wilhelm, Fabrice; Rogalev, Andrei; Hen, Amir; Ney, Andreas

2018-05-01

Low temperature Co K-edge x-ray magnetic circular dichroism spectra at different field cooling conditions were recorded to study the imprinted magnetization in antiferromagnetic (AFM) Co doped ZnO (Co:ZnO) films which manifests itself in a vertical exchange bias effect. Co:ZnO films with 50% and 60% doping concentrations were investigated to provide a high degree of pinned magnetic moments. The measurements reveal a change at the main absorption energy of the spectra, while the signal obtained at the pre-edge stays unaffected by the cooling conditions. Therefore, the pinned uncompensated AFM moments, resulting in an imprinted magnetization, are predominantly of orbital character and are independent of ferromagnetic layers.

Implementation of an integrating sphere for the enhancement of noninvasive glucose detection using quantum cascade laser spectroscopy

NASA Astrophysics Data System (ADS)

Werth, Alexandra; Liakat, Sabbir; Dong, Anqi; Woods, Callie M.; Gmachl, Claire F.

2018-05-01

An integrating sphere is used to enhance the collection of backscattered light in a noninvasive glucose sensor based on quantum cascade laser spectroscopy. The sphere enhances signal stability by roughly an order of magnitude, allowing us to use a thermoelectrically (TE) cooled detector while maintaining comparable glucose prediction accuracy levels. Using a smaller TE-cooled detector reduces form factor, creating a mobile sensor. Principal component analysis has predicted principal components of spectra taken from human subjects that closely match the absorption peaks of glucose. These principal components are used as regressors in a linear regression algorithm to make glucose concentration predictions, over 75% of which are clinically accurate.

An evolving trio of hybrid stars: C111

NASA Technical Reports Server (NTRS)

Sonneborn, George (Technical Monitor); Dupree, Andrea K.

2005-01-01

Hybrid stars are a class of cool, luminous single stars originally identified based on the appearance of their ultraviolet IUE spectra. C IV emission is present (signifying temperatures of at least lo5 K), and asymmetric emission cores of Mg I1 are found, accompanied by absorption features at low and high velocities, indicating a massive stellar wind and circumstellar material. Many members of this class have been identified and X-rays have been detected from most hybrids. They represent the critical evolutionary state between coronal-like objects and the Alpha Ori-like objects and assume a pivotal role in the definition of coronal evolution, atmospheric heating processes, and mechanisms to drive winds of cool stars.

Photoconductivity in BiFeO3 thin films

NASA Astrophysics Data System (ADS)

Basu, S. R.; Martin, L. W.; Chu, Y. H.; Gajek, M.; Ramesh, R.; Rai, R. C.; Xu, X.; Musfeldt, J. L.

2008-03-01

The optical properties of epitaxial BiFeO3 thin films have been characterized in the visible range. Variable temperature spectra show an absorption onset near 2.17eV, a direct gap (2.667±0.005eV at 300K), and charge transfer excitations at higher energy. Additionally, we report photoconductivity in BiFeO3 films under illumination from a 100mW /cm2 white light source. A direct correlation is observed between the magnitude of the photoconductivity and postgrowth cooling pressure. Dark conductivities increased by an order of magnitude when comparing films cooled in 760 and 0.1Torr. Large increases in photoconductivity are observed in light.

Implications of high-velocity interstellar H I absorption features

NASA Technical Reports Server (NTRS)

Cowie, L.; York, D. G.; Laurent, C.; Vidal-Madjar, A.

1979-01-01

Contributions to the interstellar H I column density at high velocities from immediate postshock gas and from the cooling gas behind a shock are compared. The detection of high-velocity H I in L-epsilon and L-delta for Iota Ori is reported and interpreted as cooling gas behind a shock of 100 km/s velocity. The immediate postshock gas should be observable for shock velocities greater than 200 km/s and permits direct determination of the velocities of adiabatic shocks in the interstellar medium. It is pointed out that interstellar L-alpha and L-beta lines may not have purely Lorentzian profiles if high-velocity H I is a widespread phenomenon.

Refractive Index and Absorption Attribution of Highly Absorbing Brown Carbon Aerosols from an Urban Indian City-Kanpur.

PubMed

Shamjad, P M; Tripathi, S N; Thamban, Navaneeth M; Vreeland, Heidi

2016-11-24

Atmospheric aerosols influence Earth's radiative balance, having both warming and cooling effects. Though many aerosols reflect radiation, carbonaceous aerosols such as black carbon and certain organic carbon species known as brown carbon have the potential to warm the atmosphere by absorbing light. Black carbon absorbs light over the entire solar spectrum whereas brown carbon absorbs near-UV wavelengths and, to a lesser extent, visible light. In developing countries, such as India, where combustion sources are prolific, the influence of brown carbon on absorption may be significant. In order to better characterize brown carbon, we present experimental and modeled absorption properties of submicron aerosols measured in an urban Indian city (Kanpur). Brown carbon here is found to be fivefold more absorbing at 365 nm wavelength compared to previous studies. Results suggest ~30% of total absorption in Kanpur is attributed to brown carbon, with primary organic aerosols contributing more than secondary organics. We report the spectral brown carbon refractive indices along with an experimentally constrained estimate of the influence of aerosol mixing state on absorption. We conclude that brown carbon in Kanpur is highly absorbing in nature and that the mixing state plays an important role in light absorption from volatile species.

Refractive Index and Absorption Attribution of Highly Absorbing Brown Carbon Aerosols from an Urban Indian City-Kanpur

PubMed Central

Shamjad, P. M.; Tripathi, S. N.; Thamban, Navaneeth M.; Vreeland, Heidi

2016-01-01

Atmospheric aerosols influence Earth’s radiative balance, having both warming and cooling effects. Though many aerosols reflect radiation, carbonaceous aerosols such as black carbon and certain organic carbon species known as brown carbon have the potential to warm the atmosphere by absorbing light. Black carbon absorbs light over the entire solar spectrum whereas brown carbon absorbs near-UV wavelengths and, to a lesser extent, visible light. In developing countries, such as India, where combustion sources are prolific, the influence of brown carbon on absorption may be significant. In order to better characterize brown carbon, we present experimental and modeled absorption properties of submicron aerosols measured in an urban Indian city (Kanpur). Brown carbon here is found to be fivefold more absorbing at 365 nm wavelength compared to previous studies. Results suggest ~30% of total absorption in Kanpur is attributed to brown carbon, with primary organic aerosols contributing more than secondary organics. We report the spectral brown carbon refractive indices along with an experimentally constrained estimate of the influence of aerosol mixing state on absorption. We conclude that brown carbon in Kanpur is highly absorbing in nature and that the mixing state plays an important role in light absorption from volatile species. PMID:27883083

The development of a solar residential heating and cooling system

NASA Technical Reports Server (NTRS)

1975-01-01

The MSFC solar heating and cooling facility was assembled to demonstrate the engineering feasibility of utilizing solar energy for heating and cooling buildings, to provide an engineering evaluation of the total system and the key subsystems, and to investigate areas of possible improvement in design and efficiency. The basic solar heating and cooling system utilizes a flat plate solar energy collector, a large water tank for thermal energy storage, heat exchangers for space heating, and an absorption cycle air conditioner for space cooling. A complete description of all systems is given. Development activities for this test system included assembly, checkout, operation, modification, and data analysis, all of which are discussed. Selected data analyses for the first 15 weeks of testing are included, findings associated with energy storage and the energy storage system are outlined, and conclusions resulting from test findings are provided. An evaluation of the data for summer operation indicates that the current system is capable of supplying an average of 50 percent of the thermal energy required to drive the air conditioner. Preliminary evaluation of data collected for operation in the heating mode during the winter indicates that nearly 100 percent of the thermal energy required for heating can be supplied by the system.

Quantitative theoretical analysis of lifetimes and decay rates relevant in laser cooling BaH

NASA Astrophysics Data System (ADS)

Moore, Keith; Lane, Ian C.

2018-05-01

Tiny radiative losses below the 0.1% level can prove ruinous to the effective laser cooling of a molecule. In this paper the laser cooling of a hydride is studied with rovibronic detail using ab initio quantum chemistry in order to document the decays to all possible electronic states (not just the vibrational branching within a single electronic transition) and to identify the most populated final quantum states. The effect of spin-orbit and associated couplings on the properties of the lowest excited states of BaH are analysed in detail. The lifetimes of the A2Π1/2, H2Δ3/2 and E2Π1/2 states are calculated (136 ns, 5.8 μs and 46 ns respectively) for the first time, while the theoretical value for B2 Σ1/2+ is in good agreement with experiments. Using a simple rate model the numbers of absorption-emission cycles possible for both one- and two-colour cooling on the competing electronic transitions are determined, and it is clearly demonstrated that the A2Π - X2Σ+ transition is superior to B2Σ+ - X2Σ+ , where multiple tiny decay channels degrade its efficiency. Further possible improvements to the cooling method are proposed.

Advanced radial inflow turbine rotor program: Design and dynamic testing

NASA Technical Reports Server (NTRS)

Rodgers, C.

1976-01-01

The advancement of small, cooled, radial inflow turbine technology in the area of operation at higher turbine inlet temperature is discussed. The first step was accomplished by designing, fabricating, and subjecting to limited mechanical testing an advanced gas generator rotating assembly comprising a radial inflow turbine and two-stage centrifugal compressor. The radial inflow turbine and second-stage compressor were designed as an integrally machined monorotor with turbine cooling taking place basically by conduction to the compressor. Design turbine inlet rotor gas temperature, rotational speed, and overall gas generator compressor pressure ratio were 1422 K (2560 R), 71,222 rpm, and 10/1 respectively. Mechanical testing on a fabricated rotating assembly and bearing system covered 1,000 cold start/stop cycles and three spins to 120 percent design speed (85,466 rpm).

Laser system for natural gas detection. Phase 1: Laboratory feasibility studies

NASA Technical Reports Server (NTRS)

Grant, W. B.; Hinkley, E. D., Jr.

1982-01-01

This project demonstrated the feasibility of using laser remote sensing technology as a tool for leak survey work in natural gas distribution systems. A laboratory device was assembled using a pair of helium neon (HeNe) lasers to measure methane. One HeNe laser emits radiation at a wavelength of 3.3922 micrometers, which corresponds to a strong absorption feature of methane, while the other emits radiation at a wavelength of 3.3911 micrometers, which corresponds to a weak absorption by methane. As a particular area is scanned for leaks, the laser is pointed at convenient topographic targets within its operating range, about 25 m. A portion of the backscattered radiation is collected by a receiver and focused onto an indium antimonide (InSb) photodetector, cooled to 77K. Methane concentrations were determined from the differential absorption at the two wavelengths for the backscattered radiation.

Laboratory absorption spectra of molecules at interstellar cloud temperatures - First measurements on CO at about 97 nm

NASA Technical Reports Server (NTRS)

Smith, P. L.; Yoshino, K.; Stark, G.; Ito, K.; Stevens, M. H.

1991-01-01

In the 91-100 nm spectral region, where absorption of photons by interstellar CO usually leads to dissociation, laboratory spectra obtained at 295 K show that most CO bands are both overlapped and perturbed. Reliable band oscillator strengths cannot be extracted from such spectra. As a consequence, synthetic extreme-ultraviolet absorption spectra for CO at the low temperatures that prevail in interstellar clouds are uncertain. A supersonic expansion technique has been used to cool CO to 30 K and three bands in the 97-nm region have been studied with high spectral resolution. The measured spectrum at 30 K is in reasonable agreement with some published modeled spectra, but the ratios of integrated cross sections are somewhat different from those determined from low resolution spectra obtained at 295 K, in which the bands are blended.