85 research outputs found
Diversity and altitudinal niche width characteristics for 35 taxa of the Papua New Guinea Frullania flora with consideration of sibling pairs
The Frullania taxa on Mount Albert Edward, Papua New Guinea, form many associations that suggest a high degree of niche similarity, but at different altitudes, different associations form. The species diversity of the genus is greatest at the middle altitudes and least in the dry lowlands. This altitudinal separation is apparent in the niche widths of the taxa. The members of the four sibling taxa pairs examined exhibit distinct altitudinal niches, suggesting that the sibling taxa are distinct, with different niche optima
Human Factors and ISS Medical Systems: Highlights of Procedures and Equipment Findings
As part of the Space Human Factors Engineering Critical Questions Roadmap, a three year Technology Development Project (TDP) was funded by NASA Headquarters to examine emergency medical procedures on ISS. The overall aim of the emergency medical procedures project was to determine the human factors issues in the procedures, training, communications and equipment, and to recommend solutions that will improve the survival rate of crewmembers in the event of a medical emergency. Currently, each ISS crew remains on orbit for six month intervals. As there is not standing requirement for a physician crewmember, during such time, the maintenance of crew health is dependant on individual crewmembers. Further, in the event of an emergency, crew will need to provide prolonged maintenance care, as well as emergency treatment, to an injured crewmember while awaiting transport to Earth. In addition to the isolation of the crew, medical procedures must be carried out within the further limitations imposed by the physical environment of the space station. For example, in order to administer care on ISS without the benefit of gravity, the Crew Medical Officers (CMOs) must restrain the equipment required to perform the task, restrain the injured crewmember, and finally, restrain themselves. Both the physical environment and the physical space available further limit the technology that can be used onboard. Equipment must be compact, yet able to withstand high levels of radiation and function without gravity. The focus here is to highlight the human factors impacts from our three year project involving the procedures and equipment areas that have been investigated and provided valuable to ISS and provide groundwork for human factors requirements for medical applications for exploration missions
VALIDATION OF A 3-DIMENSIONAL VIDEO MOTION CAPTURE SYSTEM FOR DETERMINING BARBELL POWER AND VELOCITY DURING THE BENCH PRESS
Andrew C. Fry, Luke Bradford, Trent Herda, Joseph Weir FACSM, Michael Lane, Matthew Andre, Andrea Hudy, J. Deckert and J. Siedlik.Neuromechanics Laboratory and Kansas Athletics Inc., University of Kansas, Lawrence, KS
Analyses of barbell kinetics and kinematics have typically required the use of force plates, tether-based position transducers, or digitized video analysis. PURPOSE: To determine the validity of a 3-dimensional video markerless motion capture system for determining barbell kinetics and kinematics. METHODS: Two 3-D video cameras sampling at 30 Hz and mounted on the top of a power rack were interfaced with a self-contained computer and software system, and operated with a touch screen (EliteForm, Lincoln, NE). For laboratory comparison purposes, a ceiling–mounted linear position transducer (Unimeasure, Corvallis, OR) was attached via a tether to the barbell. Data from the position transducer was sampled at 1000 Hz using a BioPac data acquisition system (Goleta, CA). Velocity (m.s-1) and power (W) were derived using LabView software (National Instruments, Austin, TX). One weight-trained male subject (age = 25 yrs, hgt = 1.75 m, BW = 82.6 kg, 1 RM = 161.0 kg) performed the barbell bench press exercise for 10 sets x 1 repetition at 30, 40, 50, 60, 70 and 80% 1 RM loads using maximal acceleration during the concentric phase. Dependent variables included peak (PV) and X̅ velocity (MV) and peak (PP) and X̅ power (MP). Linear regressions between lab-derived and 3-D video-derived data provided correlation coefficients, and regression slopes (b). Bland-Altman plots were used to determine X̅ differences, from which effect sizes (Cohen’s D) and % error for the 3-D camera system was determined. RESULTS: Lab-derived mean values for all loads ranged as follows; MV = 0.36 – 1.00 m.s-1, PV = 0.47 – 1.60 m.s-1, MP = 460.9 – 621.6 W, and PP = 619.9 – 1055.6 W.
CONCLUSION: The 3-D video markerless motion capture system provided accurate and valid barbell velocity and power data for the bench press exercise.
Supported in part by Nebraska Global LL
Turbulent separated shear flow control by surface plasma actuator: experimental optimization by genetic algorithm approach
The final publication is available at Springer via http://dx.doi.org/10.1007/s00348-015-2107-3The potential benefits of active flow control are no more debated. Among many others applications, flow control provides an effective mean for manipulating turbulent separated flows. Here, a nonthermal surface plasma discharge (dielectric barrier discharge) is installed at the step corner of a backward-facing step (U0 = 15 m/s, Reh = 30,000, Re¿ = 1650). Wall pressure sensors are used to estimate the reattaching location downstream of the step (objective function #1) and also to measure the wall pressure fluctuation coefficients (objective function #2). An autonomous multi-variable optimization by genetic algorithm is implemented in an experiment for optimizing simultaneously the voltage amplitude, the burst frequency and the duty cycle of the high-voltage signal producing the surface plasma discharge. The single-objective optimization problems concern alternatively the minimization of the objective function #1 and the maximization of the objective function #2. The present paper demonstrates that when coupled with the plasma actuator and the wall pressure sensors, the genetic algorithm can find the optimum forcing conditions in only a few generations. At the end of the iterative search process, the minimum reattaching position is achieved by forcing the flow at the shear layer mode where a large spreading rate is obtained by increasing the periodicity of the vortex street and by enhancing the vortex pairing process. The objective function #2 is maximized for an actuation at half the shear layer mode. In this specific forcing mode, time-resolved PIV shows that the vortex pairing is reduced and that the strong fluctuations of the wall pressure coefficients result from the periodic passages of flow structures whose size corresponds to the height of the step model.Peer ReviewedPostprint (author's final draft
Does volcanic ash re-mobilisation from its deposits on land contribute to ocean fertilisation?
Recent studies on the iron fertilisation of the surface ocean with volcanic ash are all focused on the immediate time after a volcanic eruption. Here we investigate a post-eruptive effect: volcanic ash may be re-mobilised into the atmosphere from ash deposits on land by wind (Langmann, 2013). Therefore it may fertilise the surface ocean during periods of months to years and not only during a volcanic eruption. Observations confirm such re-mobilisation events, e.g. after the volcanic eruptions of Katmai, Alaska (1912), Mt. Hudson, Chile (1991) and Eyjafjallajökull, Iceland (2010). Even though the Katmai eruption is more than 100 years ago, volcanic ash re-mobilisation events occur until today. Here we report first model simulation results after the volcanic eruption of Mt. Hudson, Chile (1991) focusing on the deposition of volcanic ash into the Atlantic sector of the Antarctic Ocean and its potential to iron- fertilise surface ocean waters
Selection of control parameters in a control system with a DC electric series motor using evolutionary algorithm
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