Computer programs for shielding problems in manned space vehicles

Computer programs for shielding problems in manned space vehicles - proton penetration code

Photovoltaic array: Power conditioner interface characteristics

The electrical output (power, current, and voltage) of flat plate solar arrays changes constantly, due primarily to changes in cell temperature and irradiance level. As a result, array loads such as dc-to-ac power conditioners must be capable of accommodating widely varying input levels while maintaining operation at or near the maximum power point of the array. The array operating characteristics and extreme output limits necessary for the systematic design of array load interfaces under a wide variety of climatic conditions are studied. A number of interface parameters are examined, including optimum operating voltage, voltage energy, maximum power and current limits, and maximum open circuit voltage. The effect of array degradation and I-V curve fill factor or the array power conditioner interface is also discussed. Results are presented as normalized ratios of power conditioner parameters to array parameters, making the results universally applicable to a wide variety of system sizes, sites, and operating modes

Data compilation and evaluation of space shielding problems. Radiation hazards in space, volume III

Radiation hazards of interplanetary space and related shielding problem

Proof of a Defect or Defectiveness

The authors discuss the practical and legal problems involved in proving a defect in a product liability case. The essential differences between design defects and construction defects are characterized in terms of the requisites of proof of each. Primary emphasis is placed upon the effective and efficient discovery and utilization of evidence concerning design and construction standards and the extent to which these standards were considered and implemented in the design or construction process

I\u27ll Take It for What It Is Worth -- The Use of Hearsay Evidence by Labor Arbitrators: A Primer and Modest Proposal

This article considers these and other selected problems dealing with hearsay evidence that are likely to be encountered in the arbitral forum. It is our thesis that arbitrators do and should credit some (but not all) forms of hearsay evidence, but that the arbitral process is not served by admitting all evidence and taking it for what it is worth. Further, we believe when an advocate\u27s case against a grievant consists entirely of hearsay evidence, and there is no reliable substitute for cross examination or equivalent circumstantial guarantees of trustworthiness, the grievant should prevail. Only in the rarest of cases will management prevail when its evidence consists entirely of hearsay evidence

Do Agency Administrative Changes Affect the Effectiveness and Efficiency of DHR Employees?

This study examined the perceived effectiveness and efficiency of DHR employees before and after agency administrative changes. Results indicated that the employees\u27 perceptions of effectiveness and efficiency after agency administrative changes were not significantly affected. The employees also felt that communication was the major factor hindering them in becoming more effective and efficient

Proof of a Defect or Defectiveness

The authors discuss the practical and legal problems involved in proving a defect in a product liability case. The essential differences between design defects and construction defects are characterized in terms of the requisites of proof of each. Primary emphasis is placed upon the effective and efficient discovery and utilization of evidence concerning design and construction standards and the extent to which these standards were considered and implemented in the design or construction process

Cascaded Fresnel Lens Antenna for Scan Loss Mitigation in Millimeter-Wave Access Points

Millimeter wave lens antennas will be essential for future wireless access. Conventionally, they increase the gain in the boresight direction only. In this paper, cascaded Fresnel zone plate lenses are combined with a phased array to increase the gain at wide steering angles of ±52°. The side lenses are tilted to align with the maximum steering angle, and cascaded to increase the focusing gain. The inner lenses increase the gain by 2.45 dB at boresight, and by 3.19 dB at the maximum steering angle. When the side lenses are repositioned, the simulated focusing gain increases to 4.69 dB. Asymmetric amplitude distributions are proposed to prevent the main lobe from splitting. An 8-dement 7-lens prototype operating at 28 GHz achieved a gain from 12.96 dBi to 15.35 dBi with a bandwidth of at least 1.3 GHz for all measured beam directions. The maximum measured azimuthal beamwidth was 27°. A design procedure and a theoretical analysis of diffraction through the lenses are provided. By increasing the SNR, this beamfonning antenna could improve the coverage of 3-sector 5G microcell base stations, and support gigabit wireless links for vehicular, rail, and satellite communications

High temperature compounds for turbine vanes Final report

Mechanical properties of high temperature composites for use as turbine stator vane

Conformal Transmitarray for Scan Loss Mitigation with Thinned Reconfiguration

A conformal transmitarray with thinned control is presented, operating at 28 GHz. Its side panels are rotated to align with the maximum steering angle, increasing the gain and reducing the scan loss. The transmitarray is fed by an 8-element linear phased array antenna. Beam focusing to +/- 53 degrees is demonstrated for two different directions, using combinations of crossed-slot unit cells. A unit cell placement rule is proposed to significantly reduce (i.e. thin) the required number of reconfigurable unit cells. A filling factor of 43% was achieved compared to a fully populated design. This reduces the cost and biasing complexity. By minimising scan loss, this antenna could improve the performance of 5G small-cell access points