Aerodynamic interactions from reaction controls for lateral control of the M2-F2 lifting-body entry configuration at transonic and supersonic and supersonic Mach numbers

Tests were conducted in the Ames 6 by 6 foot wind tunnel to determine the interaction of reaction jets for roll control on the M2-F2 lifting-body entry vehicle. Moment interactions are presented for a Mach number range of 0.6 to 1.7, a Reynolds number range of 1.2 x 10 to the 6th power to 1.6 x 10 to the 6th power (based on model reference length), an angle-of-attack range of -9 deg to 20 deg, and an angle-of-sideslip range of -6 deg to 6 deg at an angle of attack of 6 deg. The reaction jets produce roll control with small adverse yawing moment, which can be offset by horizontal thrust component of canted jets

Allelic variants of KLK2 gene predict presence of prostate cancer at biopsy

Objective: Several single nucleotide polymorphisms associated with prostate cancer risk have been reported in recent years. We evaluated polymorphisms in the human glandular kallikrein 2 (KLK2) genes because the protein product of this gene is known to be increased in prostate cancer. Materials and methods: Blood samples were collected from sixty patients who underwent prostate biopsy sectioning, and from their genomic DNA the SNPs in KLK2 gene were investigated by direct DNA sequencing. Another 138 archived prostate tissue sections were also evaluated using the TaqMan SNP genotyping assay. Results: Eighteen known SNPs were identified in the KLK2 gene. The SNPs were located in introns, coding exons and untranslated regions of the gene. Further analysis showed that two of the SNPs were associated with prostate disease. The T/T allele of rs198977 was significantly predictive of the presence of prostate cancer at biopsy and was also associated with high tumour grade. The A/A allele of rs2664155 was also significantly associated with the presence of benign hyperplasia at biopsy. Conclusion: Our results support previous reports of association of the rs198977 SNP with prostate cancer risk and also indicated a link with the disease phenotype. However, the second SNP (rs2664155) was more associated with benign hyperplasia than prostate cancer risk. The method of TaqMan SNP genotyping could be clinically useful in genetic screening and risk stratification of patients for prostate diseases

Preliminary performance estimates of an oblique, all-wing, remotely piloted vehicle for air-to-air combat

A computerized aircraft synthesis program has been used to assess the effects of various vehicle and mission parameters on the performance of an oblique, all-wing, remotely piloted vehicle (RPV) for the highly maneuverable, air-to-air combat role. The study mission consists of an outbound cruise, an acceleration phase, a series of subsonic and supersonic turns, and a return cruise. The results are presented in terms of both the required vehicle weight to accomplish this mission and the combat effectiveness as measured by turning and acceleration capability. This report describes the synthesis program, the mission, the vehicle, and results from sensitivity studies. An optimization process has been used to establish the nominal RPV configuration of the oblique, all-wing concept for the specified mission. In comparison to a previously studied conventional wing-body canard design for the same mission, this oblique, all-wing nominal vehicle is lighter in weight and has higher performance

Statistical evaluation of control inputs and eye movements in the use of instruments clusters during aircraft landing

Two different types of analyses were done on data from a study in which eye movements and other variables were recorded while four pilots executed landing sequences in a Boeing 737 simulation. Various conditions were manupulated, including changes in turbulence, starting position, and instrumentation. Control inputs were analyzed in the context of the various conditions and compared against ratings of workload obtained using the Cooper-Harper scale. A number of eye-scanning measures including mean dwell time and transition from one instrument to another were entered into a principal components factor analysis. The results show a differentiation between control inputs and eye-scanning behavior. This shows the need for improved definition of workload and experiments to uncover the important differences among control inputs, eye-scanning and cognitive processes of the pilot

Quantifying Operational Constraints of Low-Latency Telerobotics for Planetary Surface Operations

NASA's SLS and Orion crew vehicle will launch humans to cislunar space to begin the new era of space exploration. NASA plans to use the Orion crew vehicle to transport humans between Earth and cislunar space where there will be a stationed habitat known as the Deep Space Gateway (DSG). The proximity to the lunar surface allows for direct communication between the DSG and surface assets, which enables low-latency telerobotic exploration. The operational constraints for telerobotics must be fully explored on Earth before being utilized on space exploration missions. We identified two constraints on space exploration using low-latency surface telerobotics and attempts to quantify these constraints. A constraint associated with low-latency surface telerobotics is the bandwidth available between the orbiting command station and the ground assets. The bandwidth available will vary during operation. As a result, it is critical to quantify the operational video conditions required for effective exploration. We designed an experiment to quantify the threshold frame rate required for effective exploration. The experiment simulated geological exploration via low-latency surface telerobotics using a COTS rover in a lunar analog environment. The results from this experiment indicate that humans should operate above a threshold frame rate of 5 frames per second. In a separate, but similar experiment, we introduced a 2.6 second delay in the video system. This delay recreated the latency conditions present when operating rovers on the lunar farside from an Earth-based command station. This time delay was compared to low-latency conditions for teleoperation at the DSG ($\leq$0.4 seconds). The results from this experiment show a 150% increase in exploration time when the latency is increased to 2.6 seconds. This indicates that such a delay significantly complicates real-time exploration strategies.Comment: 10 pages, 8 figures, Proceedings of the IEEE Aerospace Conference, Big Sky, MT. arXiv admin note: text overlap with arXiv:1706.0375

The impact of active workstations on workplace productivity and performance: a systematic review

Active workstations have been recommended for reducing sedentary behavior in the workplace. It is important to understand if the use of these workstations has an impact on worker productivity. The aim of this systematic review was to examine the effect of active workstations on workplace productivity and performance. A total of 3303 articles were initially identified by a systematic search and seven articles met eligibility criteria for inclusion. A quality appraisal was conducted to assess risk of bias, confounding, internal and external validity, and reporting. Most of the studies reported cognitive performance as opposed to productivity. Five studies assessed cognitive performance during use of an active workstation, usually in a single session. Sit-stand desks had no detrimental effect on performance, however, some studies with treadmill and cycling workstations identified potential decreases in performance. Many of the studies lacked the power required to achieve statistical significance. Three studies assessed workplace productivity after prolonged use of an active workstation for between 12 and 52 weeks. These studies reported no significant effect on productivity. Active workstations do not appear to decrease workplace performance

The development of a high temperature static strain gage system

The objective of this program is to develop electrical resistance strain gages which will permit the measurement of static strains on nickel and cobalt superalloy parts inside gas turbine engines running on a test stand. The specific goal is to develop a complete system able to make strain measurements up to plus or minus 2000 mu strain with a total error of no more than plus or minus 10 percent over a 50 hour period at 1250 K. The initial part of this work consisted of a strain gage alloy development effort in which a variety of alloys were evaluated after being prepared by drop-casting or splat cooling

High temperature static strain gage alloy development program

The literature, applicable theory and finally an experimental program were used to identify new candidate alloy systems for use as the electrical resistance elements in static strain gages up to 1250K. The program goals were 50 hours of use in the environment of a test stand gas turbine engine with measurement accuracies equal to or better than 10 percent of full scale for strains up to + or - 2000 microstrain. As part of this effort, a computerized electrical resistance measurement system was constructed for use at temperatures between 300K and 1250K and heating and cooling rates of 250K/min and 10K/min. The two best alloys were an iron-chromium-aluminum alloy and a palladium base alloy. Although significant progress was made, it was concluded that a considerable additional effort would be needed to fully optimize and evaluate these candidate systems

Equilibrium and Kinetic Study of the Substitution Reactions of Pentacarbonylaminetungsten (O) with Triphenylphosphine

A kinetic and equilibrium study of the reaction of triphenylphosphine (PPh3) with pentacarbonylaminetungsten (O) [(CO)5WNH2C6H5] has been reported previously. Equilibrium constants for the reaction (CO)5WNH2C6H5 + PPh3 = (CO)5W[P(C6H5)3] + C6H5NH2 in toluene were reported to be 17.1, 49.2 and 65.7 respectively. In addition, the entropy change (ΔS) for the reaction was found to be 86±5 cal mol-1 deg-1. In this study the above reaction was reinvestigated in order to determine the cause of the abnormally large entropy change. The reaction was investigated spectrophotometrically by monitoring the absorption of the aniline complex at 406 nm. Other reactants and products of the reaction do not absorb significantly at this wavelength. The reaction was examined over a range of ligand concentrations and reaction temperatures. When the conditions of the previous work were duplicated it was found that the absorption due to the aniline complex disappeared completely. Concentrations of starting reactants were adjusted in order to shift the equilibrium position to the left. In no experiment was there obtained any evidence for equilibrium. Therefore, if an equilibrium does exist, the equilibrium constant must be much larger than that previously reported. Furthermore, it was previously reported that equilibrium for the reaction is established in two days. In this study it was found that the aniline complex continues to react beyond two days in all experiments. An attempt to determine the equilibrium constant for the reaction by approaching the equilibrium from the opposite direction was not successful. The intensity of the carbonyl absorption of (CO)5WPPh3 did not diminish with time upon treatment of this compound with a large excess of aniline nor was there any appearance of aniline complex. It is concluded that the position of equilibrium cannot be determined by the methods utilized in the previous study. The previous workers reported that the aniline complex is stable in the presence of a large excess of aniline. In this study it has been found that this is not true for temperatures above 30° and that at temperatures above 40° rapid decomposition occurs. It is the conclusion of this study that the thermodynamic data previously reported are unreliable