Man-systems evaluation of moving base vehicle simulation motion cues

A motion cue investigation program is reported that deals with human factor aspects of high fidelity vehicle simulation. General data on non-visual motion thresholds and specific threshold values are established for use as washout parameters in vehicle simulation. A general purpose similator is used to test the contradictory cue hypothesis that acceleration sensitivity is reduced during a vehicle control task involving visual feedback. The simulator provides varying acceleration levels. The method of forced choice is based on the theory of signal detect ability

Teleoperator docking simulation

A simulation study is described of the translation, station keeping and final approach segments of the teleoperator implemented at MSFC. An effort is made to identify the teleoperator visual system design parameters which influence operator performance and to determine human factors design requirements for free flying teleoperators

Earth orbital teleoperator system man-machine interface evaluation

The teleoperator system man-machine interface evaluation develops and implements a program to determine human performance requirements in teleoperator systems

Earth orbital teleoperator mobility system evaluation program

The proximity translation and final docking of the space teleoperator evaluation vehicle (STEV) with large mass and small mass satellites was studied. Operations that may be performed by the STEV during the shuttle experiments are approximated

Earth orbital teleoperator systems evaluation

The mechanical extension of the human operator to remote and specialized environments poses a series of complex operational questions. A technical and scientific team was organized to investigate these questions through conducting specific laboratory and analytical studies. The intent of the studies was to determine the human operator requirements for remotely manned systems and to determine the particular effects that various system parameters have on human operator performance. In so doing, certain design criteria based on empirically derived data concerning the ultimate control system, the human operator, were added to the Teleoperator Development Program

Earth orbital teleoperator manipulator system evaluation program

The operator's ability to perform five manipulator tip movements while using monoptic and stereoptic video systems was assessed. Test data obtained were compared with previous results to determine the impact of camera placement and stereoptic viewing on manipulator system performance. The tests were performed using the NASA MSFC extendible stiff arm Manipulator and an analog joystick controller. Two basic manipulator tasks were utilized. The minimum position change test required the operator to move the manipulator arm to touch a target contract. The dexterity test required removal and replacement of pegs

Surface lime and silicate application and crop production system effects on physical characteristics of a Brazilian Oxisol.

This work aimed to evaluate the effects of crop rotations and soil acidity amelioration on soil physical properties of an Oxisol (Rhodic Ferralsol or Red Ferrosol in the Australian Soil Classification) from October 2006 to September 2011 in Botucatu, SP, Brazil. Treatments consisted of four soybean (Glycine max)?maize (Zea mays)?rice (Oryza sativa) rotations that differed in their off-season crop, either a signal grass (Urochloa ruziziensis) forage crop, a second crop, a cover crop, or fallow. Two acid-neutralising materials, dolomitic lime (effective calcium carbonate equivalent (ECCE) = 90%) and calcium-magnesium silicate (ECCE = 80%), were surface applied to raise the soil?s base saturation to 70%. Selected soil physical characteristics were evaluated at three depths (0?0.1, 0.1?0.2, and 0.2?0.4 m). In the top 0.1 m, soil bulk density was lowest (P < 0.05) and macroporosity and aggregate stability index were greatest (P < 0.05) in the forage crop compared with all other production systems. Also, bulk density was lower (P < 0.05) and macroporosity was greater (P < 0.05) in the acid-neutralising-amended than the unamended control soil. In the 0.1?0.2-m interval, mean weight diameter and mean geometric diameter were greater (P < 0.05) in the forage crop compared with all other production systems. All soil properties evaluated in this study in the 0.2?0.4-m interval were unaffected by production system or soil amendment after five complete cropping cycles. Results of this study demonstrated that certain soil physical properties can be improved in a no-tillage soybean?maize?rice rotation using a forage crop in the off-season and with the addition of acid-neutralising soil amendments. Any soil and crop management practices that improve soil physical properties will likely contribute to sustaining long-term soil and crop productivity in areas with highly weathered, organic matter-depleted, acidic Oxisols

Water regime and fertilizer‐phosphorus source effects on greenhouse gas emissions from rice

Abstract Greenhouse gas (GHG) emissions from rice (Oryza sativa) systems have been correlated to water management practice, but to date, no study has directly evaluated three main GHGs (i.e., methane [CH4], nitrous oxide [N2O], and carbon dioxide [CO2]) under flood‐ and furrow‐irrigated conditions at the same time as affected by various fertilizer‐phosphorus (P) sources, in particular the reportedly slow‐release struvite‐P source. Therefore, the objective of this study was to evaluate the effect of water regime (flooded and furrow‐irrigated) and fertilizer‐P source (diammonium phosphate, chemically precipitated struvite, electrochemically precipitated struvite [ECST], triple superphosphate, and an unamended control) on GHG emissions and two‐ and three‐gas global warming potentials (GWP* and GWP, respectively) in the greenhouse. Methane emissions were 10 times greater (p < 0.05) under flooded (29.4 kg CH4 ha−1 season−1) than under furrow‐irrigated conditions (2.9 kg CH4 ha−1 season−1), and four times lower (p < 0.05) with ECST (3.4 kg CH4 ha−1 season−1) than other fertilizer‐P sources, while CO2 emissions were three times greater (p < 0.05) under furrow‐irrigated (23,428 kg CO2 ha−1 season−1) than under flooded (8290 kg CO2 ha−1 season−1) conditions. The GWP* under furrow‐irrigated conditions was almost 40% lower (p < 0.05) than under flooded conditions. Although N2O emissions were unaffected by fertilizer‐P source, the N2O contribution to GWP* was more than 80% under furrow‐irrigated conditions. Flood‐ and furrow‐irrigated water regimes require diversified approaches in GHG mitigation, where the best management for ECST needs to be more fully evaluated