Asymptotic statistical characterizations of p-harmonic functions of two variables

Generalizing the well-known mean-value property of harmonic functions, we prove that a p-harmonic function of two variables satisfies, in a viscosity sense, two asymptotic formulas involving its local statistics. Moreover, we show that these asymptotic formulas characterize p-harmonic functions when 1 < p < \infty. An example demonstrates that, in general, these formulas do not hold in a non-asymptotic sense.Comment: Minor changes from published version: updated author info., one updated referenc

The Ursinus Weekly, June 7, 1965

Dr. Pradervand urges active involvement • Dr. F. L. Manning to retire • Ursinus graduates 226; Michener gives address • Four UC professors win Lindback teaching awards • Chapter scholars announced • New dining hall named in honor of R. F. Wismer • Alumni awards to Moritz and Wirth • Ursinus Summer Assembly set for August 2-9 • Editorial: To the Class of 1965; Federal funds; Best in the U.S. • Board of Directors approve three faculty promotions • Ursinus theatre party travels to Stratford • YM-YWCA concert features Negro choir • A time in the sun a typical Western • Dr. van Dam plans trip through western Europe • Letters to the editor • 1965 awards and prizes • Senior thinclads earned their 4 years of glory • UC nine ends with 9-5-1 log • Most valuable players: Basketball; Track; Baseball; Wrestling; Soccer • Teacher placements • Wuenschel wins PSU assistantship • Heller awarded NDEA fellowship • Three accept Lehigh teaching assistantships • Gehman gets Kent State award • Hunter wins Yale fellowshiphttps://digitalcommons.ursinus.edu/weekly/1251/thumbnail.jp

Loop Heat Pipe with Thermal Control Valve as a Variable Thermal Link

Future lunar landers and rovers will require variable thermal links that allow for heat rejection during the lunar daytime and passively prevent heat rejection during the lunar night. During the lunar day, the thermal management system must reject the waste heat from the electronics and batteries to maintain them below the maximum acceptable temperature. During the lunar night, the heat rejection system must either be shut down or significant amounts of guard heat must be added to keep the electronics and batteries above the minimum acceptable temperature. Since guard heater power is unfavorable because it adds to system size and complexity, a variable thermal link is preferred to limit heat removal from the electronics and batteries during the long lunar night. Conventional loop heat pipes (LHPs) can provide the required variable thermal conductance, but they still consume electrical power to shut down the heat transfer. This innovation adds a thermal control valve (TCV) and a bypass line to a conventional LHP that proportionally allows vapor to flow back into the compensation chamber of the LHP. The addition of this valve can achieve completely passive thermal control of the LHP, eliminating the need for guard heaters and complex controls

Variable Conductance Heat Pipe Radiator Trade Study for Lunar Fission Power Systems

Abstract. Nuclear power systems for long-term Lunar and Martian missions present many challenges to thermal management systems, such as variable thermal loads, large temperature swings between day and night, and freezing of the working fluid. The radiator to reject the waste heat must be sized for the maximum power at the highest sink temperature. This radiator is then oversized for other conditions, such as the Lunar/Martian night, or periods when the power to be rejected is low. A Variable Conductance Heat Pipe (VCHP) radiator can passively accommodate changing thermal loads and environments. A trade study was conducted to select the best design for the heat exchanger/heat pipe interface. The interfaces that were examined were an annular evaporator, bent tubes inserted into the coolant channel and a POCO Foam saddle that engulfed the coolant channel and evaporator portion of the VCHP. The trade study showed the highest specific power was for the annular evaporator, roughly 10% higher specific power than the competing interface designs

Low-Cost Radiator for Fission Power Thermal Control

NASA Glenn Research Center (GRC) is developing fission power system technology for future Lunar surface power applications. The systems are envisioned in the 10 to 100kW(sub e) range and have an anticipated design life of 8 to 15 years with no maintenance. NASA GRC is currently setting up a 55 kW(sub e) non-nuclear system ground test in thermal-vacuum to validate technologies required to transfer reactor heat, convert the heat into electricity, reject waste heat, process the electrical output, and demonstrate overall system performance. Reducing the radiator mass, size, and cost is essential to the success of the program. To meet these goals, Advanced Cooling Technologies, Inc. (ACT) and Vanguard Space Technologies, Inc. (VST) are developing a single facesheet radiator with heat pipes directly bonded to the facesheet. The facesheet material is a graphite fiber reinforced composite (GFRC) and the heat pipes are titanium/water. By directly bonding a single facesheet to the heat pipes, several heavy and expensive components can be eliminated from the traditional radiator design such as, POC(TradeMark) foam saddles, aluminum honeycomb, and a second facesheet. A two-heat pipe radiator prototype, based on the single facesheet direct-bond concept, was fabricated and tested to verify the ability of the direct-bond joint to withstand coefficient of thermal expansion (CTE) induced stresses during thermal cycling. The thermal gradients along the bonds were measured before and after thermal cycle tests to determine if the performance degraded. Overall, the results indicated that the initial uniformity of the adhesive was poor along one of the heat pipes. However, both direct bond joints showed no measureable amount of degradation after being thermally cycled at both moderate and aggressive conditions

Intermediate Temperature Fluids Life Tests - Experiments

There are a number of different applications that could use heat pipes or loop heat pipes (LHPs) in the intermediate temperature range of 450 to 725 K (170 to 450 C), including space nuclear power system radiators, fuel cells, and high temperature electronics cooling. Historically, water has been used in heat pipes at temperatures up to about 425 K (150 C). Recent life tests, updated below, demonstrate that titanium/water and Monel/water heat pipes can be used at temperatures up to 550 K (277 C), due to water's favorable transport properties. At temperatures above roughly 570 K (300 C), water is no longer a suitable fluid, due to high vapor pressure and low surface tension as the critical point is approached. At higher temperatures, another working fluid/envelope combination is required, either an organic or halide working fluid. An electromotive force method was used to predict the compatibility of halide working fluids with envelope materials. This procedure was used to reject aluminum and aluminum alloys as envelope materials, due to their high decomposition potential. Titanium and three corrosion resistant superalloys were chosen as envelope materials. Life tests were conducted with these envelopes and six different working fluids: AlBr3, GaCl3, SnCl4, TiCl4, TiBr4, and eutectic diphenyl/diphenyl oxide (Therminol VP-1/Dowtherm A). All of the life tests except for the GaCl3 are ongoing; the GaCl3 was incompatible. As the temperature approaches 725 K (450 C), cesium is a potential heat pipe working fluid. Life tests results are also presented for cesium/Monel 400 and cesium/70-30 copper/nickel heat pipes operating near 750 K (477 C). These materials are not suitable for long term operation, due to copper transport from the condenser to the evaporator

The Ursinus Weekly, April 26, 1965

Ursinus Meistersingers present tour program • Student-Faculty show combines music, humor, satire • Library week: April 25 to May 1 • Campus Chest encouraged by enthusiastic support: One down, one to go • Campus freedom, Sunisru and you • Dr. Helfferich hosts dinner • Invitation • Shakespeare theatre festival • Last chapel May 13th • Editorial: Meistersingers concert; They\u27re all right, Jack; In the name of sweet charity • H.R.C. wages unending war: Greater than 1776 • Toward maturity • Peon or pledge? • Lacrosse team remains undefeated • Baseball team evens log; Beats W. Maryland, Johns Hopkins • Thinclads nip Swarthmore • Softballers open season with win • MSGA candidates speak out: L. Rudnyansky; R. Reed; R. Shaw • U.C. student pioneer corpsman • Ruby sales awards • Greek gleaningshttps://digitalcommons.ursinus.edu/weekly/1247/thumbnail.jp

The Ursinus Weekly, May 3, 1965

Y retreat emphasizes creation of ideal college • Stage set for Fenwickian mouse • Ferguson, Dawson report $1,700 for Campus Chest • Psych Club elects officers • Bishop\u27s Players present An enemy of the people • Waiters\u27 banquet • Starvation: Paradox of plenty • Bali Ha\u27i theme for annual Spring Festival • Active electioneering marks class elections • Editorial: MSGA election; UC traditions and manners • Letters to the editor • One language for the world • Nine overseas students enrolled at Ursinus • Admissions dilemma • Injured thinclads bow at PMC; Win triangular meet at Hopkins • UC nine wins two: Beat F&M, Lebanon Valley • UC girls drop match to W.C. • Lacrosse team whips W. Chester • Greek gleanings • Advertising and PR seminarhttps://digitalcommons.ursinus.edu/weekly/1248/thumbnail.jp

The Lantern Vol. 31, No. 2, May 1964

• The High, Forbidding Wall • Sonnet One • Sceptic • The Witch, the Prince, and the Princess • Portrait in Gold and Black • The Music of the Drum • Sweat It, Jack • Cold Blue and the Moon • Another Carpenter: Circa 1963 • At a Conference of Colonial Historians • Pineland Places • Diasia to Death • Hey!... • The Hour • I\u27ll Not Returnhttps://digitalcommons.ursinus.edu/lantern/1086/thumbnail.jp