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Mechanically and capillary pumped two-phase heat transport systems are currently developed to meet the high power and long transport distance requirements of thermal management systems for future spacecraft. Compared to existing single-phase systems, two-phase loops offer important advantages: reduced overall mass and pumping power consumption, virtually isothermal behaviour, adjustable working temperature, insensitivity to variations in heat load and sink temperature, and high flexibility with respect to the location of heat sources within the loop. As two-phase flow and heat transfer in low-gravity environment is expected to (considerably) differ from terrestrial behaviour, the technology of two-phase heat transport systems and their components is to be demonstrated in orbit. Therefore a Dutch-Belgian Two-Phase experiment has been developed within the ESA In-Orbit Technology Demonstration Programme.

Future space missions will encounter a range of challenging thermal environments. The extended missions require a new generation of heat pump technologies. Zeolite/vapor heat pump technology (1) utilizing a condensing/evaporating refrigerant holds considerable promise for space applications due to the variable temperature and variable load capabilities of these systems. Zeolite heat pump systems involve no moving parts and could be made lightweight. To understand the performance of the zeolite/vapor heat pump, a bench scale zeolite/vapor heat pump test stand was built at the Johnson Space Center. The core of the test stand is a 0.12 meter in diameter by 0.33 meter long adsorption/desorption heat exchanger bed, which was loaded with one pound of zeolite beads along with a heat transfer material, Duocell. The test bed was designed for evaluating heat transfer performance for one pound of zeolite with a given heat source of 100 watts applied to the water in the evaporator.

Experiment packages are often flown on the NASA KC-135 to obtain information during conditions of microgravity. Accelerations different from 1-g and acceleration fluctuations can significantly affect experimental processes and instrumentation. For this reason, it may be very important to have an accurate knowledge of acceleration conditions prior to flight. This paper provides the acceleration characteristics during KC-135 flights and briefly discusses the implications of acceleration fields on two phase flow testing.

Studies of closed environments, Sick Building Syndrome (SBS) and NASA's Water Recovery Test reveal key issues in interdisciplinary problem-solving. Basic scientific issues include contamination control, microbial management, and passive biocides. Technological development issues include limits of uncertainty in closed biological systems, the information management and control required to support such systems, and the interface between physical-chemical (P/C) and biological life support elements. Research has indicated the limits of P/C systems in the face of biological challenge. The technological demands will drive the engineering design requirements for appropriate technology. The final engineering challenge will be designs which can be supported, augmented, and replicated by Lunar and Mars materials. With the need to create air-tight, long-use facilities, Life Support System (LSS) designs must meet similar challenges to those of closing building air-handling systems.

The United States Antarctic Program (USAP) is managed by the National Science Foundation (NSF). NSF supports a number of scientific research programs on the Antarctic continent and the surrounding oceans, including biology, glaciology, aeronomy and astrophysics, earth sciences, and ocean and climate systems. Antarctica is a difficult region to reach. It is an inhospitable place to live. At the same time, it is a nearly pristine, natural scientific laboratory where much about our planet can be learned. NSF supplies all life support and infrastructure for USAP, including two research vessels, a number of seasonal field camps, and three permanent research stations: McMurdo, South Pole, and Palmer. Last year, we presented a paper introducing ICES to Antarctica (SAE Technical Paper #921128). This paper provides updates and explores new areas of the program.

Alternate refrigerant HFC-134a has been found to be substantially more reactive than CFC-12 in the US Navy submarine catalytic burner. The burner operates at 316°C and uses a manganese dioxide/copper monoxide catalyst, Hopcalite. The reaction of HFC-134a produced hazardous quantities of HF in the outlet air in excess of the established submarine exposure limits. No other hazardous products, such as carbonyl fluoride, were detected.

The Shuttle Orbiter humidity control and carbon dioxide removal system for extended duration missions presently uses a solid amine called HS-C. This August, on board STS-62, a new solid amine called HS-C+ will be used. HS-C+ uses the same amine and the substrate material, but a different preparation process. Forty-seven breakthrough tests have been conducted to characterize the performance of HS-C+. CO2 partial pressure, bed temperature, and H2O partial pressure were varied. Eleven HS-C breakthrough tests were also run to provide a direct comparison. Under all conditions tested, HS-C+ outperformed HS-C. Both materials adsorb all CO2 and H2O available at the start of a test when the beds are fully desorbed. As the bed becomes partially loaded, the CO2 and H2O adsorption rates decrease rapidly. HS-C+ continues adsorbing all CO2 and H2O available for a longer time. Greater surface area on HS-C+ may cause the improved performance.

This paper describes the results of a series of tests that were conducted to compare the performance characteristics of the smoke detectors currently used on the Space Shuttle Orbiter and those recently developed and baselined for use on Space Station Freedom. The objective of the tests, sponsored by the National Aeronautics and Space Administration (NASA) at Johnson Space Center (JSC), was to determine if there were significant improvements in the latest sensing technology being developed for the Space Station program which could benefit the Shuttle program.

Materials circulating in a closed ecological system are classified as metabolic ones and nonmetabolic ones. Nonmetabolic substances relate to environment constituents and cultural activities. Treatment of these materials are discussed from a view point of CELSS concept. The closed system, CEEF, will be constructed in Japan in the near future. CEEF is an experiment facility with processing capacity of two adult persons, consisting of a plant module, an animal module, a habitat module and supporting facilities for the three modules. The supporting facilities are composed of artificial processors of gases, waters and wastes. The plant module has artificial and natural lighting cultivating sections.

Organic composite coated steel sheets retain their excellent corrosion resistance during cyclic corrosion tests (CCT). To clarify the corrosion behavior of these sheets during CCT, variations in corrosion products and coating components were examined. Moreover, the contribution of the corrosion products, organic composite coating, and chromate film to corrosion resistance was examined by AC impedance measurements. Formation of crystalline ZnCl2·4Zn(OH)2 and amorphous zinc carbonate were detected by X-ray diffraction (XRD) and Fourier transformation infrared spectroscopy (FT-IR). Crystalline ZnCl2·4Zn(OH)2 is formed during CCT on and under the organic composite coating. The corrosion products formed on the coating contain silicates from the silica in the organic composite coating. Consequently, the contents of zinc and silica in the coating decrease, while nickel and chromium in the chromate film and carbon in the coating remain constant during CCT.

During the initial operation of Biosphere 2, there have been important variations in atmospheric composition, particularly a decline in oxygen concentration. Testing has confirmed a low leakage rate, supporting the theory that the atmospheric dynamics are attributable to internal processes. There are many aspects of Biosphere 2 under investigation which will serve to advance the understanding of ecosystem functioning and processes.

In order to investigate the corrosion resistance of organic composite-coated steel sheets ( OCS ) in a real automotive environment, many kinds of corrosion tests were performed on test pieces and real automotive doors. Tests with a corrosive solution including iron rust were introduced to simulate the real corrosive environment of automotive doors. The relationship between the components of OCS and the corrosion resistance in the rust-including tests was examined. In addition, electrochemical studies were performed. Results indicate OCS has much better corrosion resistance than plated steel sheets with heavier coating weight in all tests. OCS shows excellent corrosion resistance in rust-free corrosive solution, however, some types of OCS do have corrosion concerns in rust-including tests. It became clear that these OCS types have an organic coating with lower cross-linking.

The use of tailored-blanks is increasing in the automotive industry as manufacturers attempt to join dissimilar steel grades and thicknesses for parts consolidation and vehicle weight savings. Two methods, laser welding in a square-butt joint and resistance mash-seam welding of overlapped edges, have been used for select applications. Several automotive grade coated sheet steels were laser and mash-seam welded and evaluated for weld integrity, formability, and corrosion resistance. Salt spray and cyclic laboratory tests, and on-vehicle exposures were used for corrosion resistance evaluations. Regarding the corrosion performance of welded parts, it was observed that the weld area provided the weakest corrosion resistance on any given panel. The corrosion performance was, in part, a function of the width of the weld fusion zone.

Proving Ground cyclic testing was used to evaluate vehicles assembled with electrogalvanized and organic composite coated electrogalvanized steel. These same materials, along with several commonly available precoated steels, were also evaluated as hem flange assemblies on towed trailers at the Proving Ground. Testing was terminated as perforation of some of the assemblies occurred. Pitting depth was used to quantitatively evaluate metal loss.

The longer-term corrosion performance of an automotive body has become one of the most important items in the portfolio of packages being used by the automotive manufacturer to attract the customer. To support the lengthy corrosion warranties currently on offer, the automotive industry has increased the amount of zinc-coated steels used in the autobody construction. This means that steel is increasingly being joined to zinc-coated steel; in some cases, a zinc-coated steel is joined to another zinc-coated steel of a different variety. This practice of bimetallic coupling has been reported in early investigations to affect the quality of the phosphate pretreatment employed on automotive painting lines. Poor pretreatment uptake at the joint areas, resulting in poor paint performance was reported. However, no clear indication was given as to whether the effect is the same over the range of bimetallic couples that may be created in the construction of the autobody.

A selection of commercially available chromium and chromium-free post phosphate rinses along with a deionized water rinse were evaluated over several zinc and zinc-alloy coated sheet steels. The test specimens were pretreated and electrocoated on-line in an automotive assembly plant. The effect of the rinse treatments on the cosmetic corrosion performance of the substrates, after 5 years of exposure in an outdoor scab corrosion test was determined. After this exposure none of the rinse treatments had performed better than deionized water rinse on zinc and zinc-iron coated sheet. The zinc-nickel coating showed improved scribe creepage when treated with the Cr+6/Cr+3 rinse. Data is provided comparing the concentration of the treatments used vs scribe creepage and chipping corrosion paint loss.

A body shell manufactured entirely of aluminum alloys is generally regarded as being insensitive to corrosion. The following paper confirms this assessment but specific types of corrosion affecting aluminum have to be avoided. The experience on which it is based includes vehicles with aluminum components driven in the field by customers, but is mainly derived from corrosion testing on specimen components and complete vehicles performed during the course of development. The most critical type of damage occurring is contact corrosion caused by other metals and conductive plastics. If the conversion coating on the metal is unsuitable, paint adhesion is insufficient and the characteristic aluminum filiform corrosion will start to form. Corrosion in crevices and beneath accumulated dirt is also likely to occur. This paper describes suitable protective measures, and also refers to repair techniques designed to avoid corrosion.

Virtual reality is an emerging technology with the potential for many engineering applications including machinery simulation. In this paper the writers describe the hardware and software components of a virtual reality system that simulates machinery. They detail the flow of information that occurs in this system and discuss the functioning of an existing system at the National Center for Supercomputing Applications (NCSA) located at the University of Illinois at Urbana-Champaign. Finally, they describe potential uses of virtual reality in product design, manufacturing, training and marketing.

A comprehensive selection of automotive sheet steels were exposed in an outdoor scab corrosion test to provide a base-line of cosmetic corrosion performance. Eighteen different coated sheet steels along with CRS as a control were processed using two commercially available zinc phosphate chemistries. The phosphating was done using both immersion and spray phosphate processes in a laboratory and an automotive assembly plant. Scribe creepage results are reported for 5 years outdoor scab exposure. Comparisons of the scribe creepage behavior of CRS, zinc, and zinc alloy coatings and the effect of the phosphate treatment are provided. An estimate of 10 years field performance is made.

Roll bars are currently a primary source of operator protection for recreational vehicles, for certain lawn and garden tractors and for small agricultural tractors. In this paper we describe a family of nonlinear models to predict the large deflection response of a roll bar due to yielding of the material. This yielding permits the structure to absorb energy. The stress-strain relationship employs a power law model. Subsequent calculation of the complementary energy stored in the structure and application of Castigliano's second theorem yield the deflection at the point of loading. To demonstrate the feasibility of this energy method in the simulation of testing of roll bars, we present numerical results for the side, vertical, and fore-aft loading cases. Results include the load-deflection response for each load case as well as the strain energy stored in the roll bar as it deforms.