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Technical Paper

The Advanced Design of a Liquid Cooling Garment Through Long-Term Research: Implications of the Test Results on Three Different Garments

The most recent goal of our research program was to identify the optimal features of each of three garments to maintain core temperature and comfort under intensive physical exertion. Four males and 2 females between the ages of 22 and 46 participated in this study. The garments evaluated were the MACS-Delphi, Russian Orlan, and NASA LCVG. Subjects were tested on different days in 2 different environmental chamber temperature/humidity conditions (24°C/H∼28%; 35°C/H∼20%). Each session consisted of stages of treadmill walking/running (250W to 700W at different stages) and rest. In general, the findings showed few consistent differences among the garments. The MACS-Delphi was better able to maintain subjects within a skin and core temperature comfort zone than was evident in the other garments as indicated by a lesser fluctuation in temperatures across physical exertion levels.
Technical Paper

Particle and Gaseous Emission Characteristics of a Formula SAE Race Car Engine

The focus of this work was the physical characterization of exhaust aerosol from the University of Minnesota Formula SAE team's engine. This was done using two competition fuels, 100 octane race fuel and E85. Three engine conditions were evaluated: 6000 RPM 75% throttle, 8000 RPM 50% throttle, and 8000 RPM 100% throttle. Dilute emissions were characterized using a Scanning Mobility Particle Sizer (SMPS) and a Condensation Particle Counter (CPC). E85 fuel produced more power and had lower particulate matter emissions at all test conditions, but more fuel was consumed.
Technical Paper

Off-shoring EMS and the Barrier of Test-in-Reliability

The history of off-road equipment manufacturing has been based on proven designs and long times between model updates. In sharp contrast with this strategy is the electronic manufacturing services (EMS) industry. The EMS industry is driven by the larger consumer product industry's continuing pressure for lower costs. Because of this, EMS tools, processes, and practices have evolved to support rapid technology and component changes. However the increasing consumer demand for features like better user-interfaces, more efficient fuel consumption, and the desire for increased operational controls in equipment have forced the off-road industry to increase the frequency of product updates to meet customers' needs. Equipment manufacturers make running changes leading to a “Learning-by-doing” development and manufacturing process. But rapid changes sometimes have an unpredictable impact on the reliability of the final product.
Technical Paper

Single-Stage Dilution Tunnel Performance

A one-stage dilution tunnel has been developed to sample and dilute diesel exhaust. The tunnel has the capability of simulating many aspects of the atmospheric dilution process. The dilution rate and overall dilution ratio, temperature, relative humidity, and residence time in the tunnel, as well as residence time and temperature in the transfer line between the tunnel and exhaust sampling point may be varied. In this work we studied the influence of the exhaust transfer line, tunnel residence time, and dilution air temperature on the exhaust particle size distribution. The influences of fuel sulfur content on the size distribution and on the sensitivity of the size distribution to dilution and sampling conditions were also examined. We do not suggest an optimum dilution scheme, but do identify critical variables.
Technical Paper

The Influence of Dilution Conditions on Diesel Exhaust Particle Size Distribution Measurements

Particle size distribution and number concentration measurements have been made in the diluted exhaust of a medium-duty, turbocharged, aftercooled, direct-injection Diesel engine using a unique variable residence time micro-dilution system that allows systematic variation of dilution and sampling conditions, and a scanning mobility particle sizer (SMPS). The measurements show that the number concentrations in the nanoparticle (Dp < 50 nm) and the ultrafine (Dp < 100 nm) ranges are very sensitive to dilution conditions and fuel sulfur content. Changes in concentration of up to two orders of magnitude have been observed when conditions are varied over the range that might be encountered in typical laboratory dilution systems. For example, at a dilution ratio of 12, dilution temperature of 32 °C, and a residence time of 1000 ms, the number concentrations reach 6 × 108 part.
Technical Paper

Forced and Directed Heat Exchange for Providing Human Body Comfort in Extreme Environments

A new methodological tool was developed consisting of a patchwork thermal cool/warm grid with great flexibility to manipulate the temperature on different areas of the body. Through conflicting temperatures on the body surface, it is possible to direct heat current to different distal or proximal areas. The effectiveness of the use of a cooled hood, gloves, socks on the overheated body was evaluated as countermeasures for balancing heat exchange. Temperature in the magistral vessels was the main source of information for understanding the mechanism of the relationship between core and shell, and shell and distal parts of the limb.
Technical Paper

Automotive Cabin Filtration In-Vehicle Test Results

This paper quantifies typical United States in-vehicle cowl area particulate filter parameters such as temperature, humidity and environmental conditions. Secondly, United States and Germany particulate filter fleet results will be included to help quantify the effect of loading on electret nonwoven particulate filter fractional efficiency and demonstrate the amount and types of particulate matter captured. Finally the paper will address the low submicron fractional filter efficiency of a simulated production “wet and dry” plate-fin automotive evaporator core.
Technical Paper

Results of the Third Long-Term Cycle at the University of Minnesota Aquifer Thermal Energy Storage (ATES) Field Test Facility

The third long-term ATES cycle (LT3) was conducted between October 1989 and March 1990. Objectives of LT3 were to demonstrate that high-temperature ATES could supply a real heating load and to simplify the water chemistry modeling. For LT3 the Field Test Facility (FTF) was connected to a nearby campus building to demonstrate the FTF's ability to meet a real heating load. For LT3 the wells were modified so that only the most permeable portions of the Ironton-Galesville aquifer were used to simplify water chemistry comparisons and modeling. The campus steam plant was the source for heat stored during LT3. A total volume of 63.2 x 103 m3 of water was injected at a rate of 54.95 m3/hr into the storage well at a mean temperature of 104.7°C from October through December 1989. Tie-in to the Animal Sciences Veterinary Medicine (ASVM) building was not completed until late December.