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A study was performed to aid in the development of accelerated test methods needed for the evaluation of absorber materials and to incorporate the methods into draft standards for consideration as consensus standards by the Americ...
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A study was performed to aid in the development of accelerated test methods needed for the evaluation of absorber materials and to incorporate the methods into draft standards for consideration as consensus standards by the American Society for Testing and Materials (ASTM). After identifying the performance requirements for absorber materials, laboratory and field studies were performed to measure performance according to the requirements. The data obtained, using twelve absorber materials, were used as the technical basis for two draft standards. This report presents the results of the research, including the proposed draft standards.
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For the past several years, the National Bureau of Standards (NBS) has supported the Consumer Product Safety Commission (CPSC) in the development of a performance standard to address the kickback hazard for chain saws. This proces...
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For the past several years, the National Bureau of Standards (NBS) has supported the Consumer Product Safety Commission (CPSC) in the development of a performance standard to address the kickback hazard for chain saws. This process included participation of the Chain Saw Manufacturers Association (CSMA), CPSC, and NBS in the development of kickback testing equipment and procedures and the study of operator/saw interactions during simulated kickback trials. The present report describes an evaluation of the CSMA and CPSC procedures for simulating 'Classical' or rotational kickback motion based primarily on analyses of high-speed films of kickback trials, the development of test procedures for simulating 'pinch' or linear kickback motion, and the simulation of kickbacks for the actuation of chain brake systems for chain saws. Included in the report is a discussion of important kickback test parameters such as mechanical energy, saw inertia, handle spacing and the interrelationships among the various parameters.
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The safety shape portable concrete barrier (PCB) has been approved for use whenplaced on a bituminous or concrete pad. Construction personnel would like to use PCBs in temporary situations along roadways where the use of a bitumin...
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The safety shape portable concrete barrier (PCB) has been approved for use whenplaced on a bituminous or concrete pad. Construction personnel would like to use PCBs in temporary situations along roadways where the use of a bituminous or concrete pad is impractical and costly. However, when PCBs are placed on soil foundations with no anchorage, they tend to dig into the soil, causing the barrier sections to rotate or overturn. The objective of this research was to develop a device which will allow temporary PCBs placed on soil foundations to translate without significant rotation when impacted by errant vehicles. This device was developed and successfully tested to Test Level 3 of the National Cooperative Highway Research Program (NCHRP) Report No. 350.
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An electric bus was modified to use hydrogen fuel for demonstration in the city of Augusta, Georgia, USA. The hydrogen fuel is stored in a solid form using an on-board metal hydride storage system. The storage system performs bett...
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An electric bus was modified to use hydrogen fuel for demonstration in the city of Augusta, Georgia, USA. The hydrogen fuel is stored in a solid form using an on-board metal hydride storage system. The storage system performs better than expected.
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The primary objective of this work is to determine the thermal, optical, and mechanical performance of several low-cost glazing and insulating materials in conjunction with a freshwater (convecting) solar pond. The effect of imple...
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The primary objective of this work is to determine the thermal, optical, and mechanical performance of several low-cost glazing and insulating materials in conjunction with a freshwater (convecting) solar pond. The effect of implementing a pond filtration system will also be examined. Progress is reported. Although actual pond performance data is not yet being collected, much progress has been made on this task during FY 1980. Several glazing materials were analyzed in various configurations and material properties of optical transmissivity and thermal conductivity were measured. In addition, the pond test facility was designed, constructed, and is nearly ready for testing the first surface treatment. (ERA citation 06:004700)
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An analytical procedure has been developed for referring collector efficiency measurements, obtained under different test conditions, to a common, or 'standard' set of conditions. The procedure applies to flat-plate liquid-type co...
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An analytical procedure has been developed for referring collector efficiency measurements, obtained under different test conditions, to a common, or 'standard' set of conditions. The procedure applies to flat-plate liquid-type collectors of conventional tube-in-sheet design. The basic Hottel-Whillier-Bliss theory is used with appropriate extensions to account for serpentine flow configurations and glazing materials with high infrared transmittance. The procedure includes a systematic method for deriving two invariant collector parameters directly from ASHRAE Standard 93-77 test results. The two parameters selected are the plate absorptance and back loss coefficient. A set of standard conditions is recommended which corresponds to favorable test conditions.
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Metaphorically, a teleoperator with master controllers projects the user's arms and hands into a remote area, Therefore, human users interact with teleoperators at a more fundamental level than they do with most human-machine syst...
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Metaphorically, a teleoperator with master controllers projects the user's arms and hands into a remote area, Therefore, human users interact with teleoperators at a more fundamental level than they do with most human-machine systems. Instead of inputting decisions about how the system should function, teleoperator users input the movements they might make if they were truly in the remote area and the remote machine must recreate their trajectories and impedance. This intense human-machine interaction requires displays and controls more carefully attuned to human motor capabilities than is necessary with most systems. It is important for teleoperated manipulators to be able to recreate human trajectories and impedance in real time. One method for assessing manipulator performance is to observe how well a system be- haves while a human user completes human dexterity tasks with it. Fitts' tapping task has been, used many times in the past for this purpose. This report describes such a performance assessment. The International Submarine Engineering (ISE) Autonomous/Teleoperated Operations Manipulator (ATOM) servomanipulator system was evalu- ated using a generic positioning accuracy task. The task is a simple one but has the merits of (1) pro- ducing a performance function estimate rather than a point estimate and (2) being widely used in the past for human and servomanipulator dexterity tests. Results of testing using this task may, therefore, allow comparison with other manipulators, and is generically representative of a broad class of tasks. Results of the testing indicate that the ATOM manipulator is capable of performing the task. Force reflection had a negative impact on task efficiency in these data. This was most likely caused by the high resistance to movement the master controller exhibited with the force reflection engaged. Measurements of exerted forces were not made, so it is not possible to say whether the force reflection helped partici- pants control force during testing.
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Neutron detectors for flight test applications use either a photomultiplier tube (PMT) or a silicon photodiode as a light detector to monitor the light output of scintillation materials. Silicon diodes lack sensitivity, so PMT's a...
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Neutron detectors for flight test applications use either a photomultiplier tube (PMT) or a silicon photodiode as a light detector to monitor the light output of scintillation materials. Silicon diodes lack sensitivity, so PMT's are used in most low flux neutron applications. The SA 1690 is presently the only Sandia qualified PMT. It has a complex temperature response requiring the selection of a temperature compensation circuit during assembly to meet accuracy requirements. Results are presented of a study which was performed to evaluate the temperature stability of two other light detectors and to compare the results with the performance of the SA 1690. (ERA citation 04:031332)
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Hands-on performance tests are the benchmark against which other measures ofproficiency should be compared. However, hands-on performance tests are expensive, time-consuming, and sometimes dangerous to personnel or equipment. This...
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Hands-on performance tests are the benchmark against which other measures ofproficiency should be compared. However, hands-on performance tests are expensive, time-consuming, and sometimes dangerous to personnel or equipment. This paper analyzes the relationship between hands-on performance tests and job-knowledge tests to propose better methods for developing job-knowledge tests and to determine when job knowledge tests could best be used in place of hands-on performance tests.
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