An Electromyographic Study of Upper Trapezius, Lower Trapezius, and Serratus Anterior Muscle Activity during Traditional and Modified Muscle Testing Positions

Purpose: The purpose of this study is to assess the muscle activity of the shoulder joint force couple induced by the upper trapezius, lower trapezius, and serratus anterior to determine if they are more effectively recruited during the traditional exercise position of forward shoulder elevation in 145° of shoulder abduction versus a modified position of shoulder external rotation while in 80° of shoulder abduction and 90° of elbow flexion Methods: Nine participants took part in this randomized study in which EMG data was collected during 4 exercise trials of 10 repetitions each on the right shoulder. EMG activity was monitored in the upper trapezius, lower trapezius, upper serratus anterior, and lower serratus anterior in the standard manual muscle testing position for the lower trapezius and a modified position with and without a two pound hand weight. The modified position had the shoulder in 80° of shoulder abduction with the elbow flexed to 90°, and palm facing the floor. Results: All subjects were able to complete the study except one who was excluded due to data corruption. Not surprisingly, more EMG activity was found in the four muscles for positions using weight compared to the no weight position regardless of the testing position implemented. The EMG activity, in the modified position, is decreased in the upper trapezius and lower serratus when compared to the standard position. This is true regardless of the presence of the two pound weight. In the lower trapezius and the upper serratus there is no significant difference between the modified and standard positions regardless of the presence of the two pound weight. Conclusion: The modified position recruits similar motor units in the lower trapezius and upper serratus. There is a significant reduction in EMG activity in the upper trapezius and lower serratus when comparing modified and standard testing positions

Pilot performance and workload whilst using an angle of attack system

Loss of control in flight is the primary category of fatal accidents within all sectors of aviation and failure to maintain adequate airspeed – leading to a stall - is often cited as a causal factor. Stalls occur when the critical angle of the aircraft is exceeded for a given airspeed. Using airspeed as an indicator of the potential to stall is an unreliable proxy. Systems that measure the angle of attack have been routinely used by military aircraft for over 50 years however rigorous academic research with respect to their effectiveness has been limited. Using a fixed-base flight simulator fitted with a simulated, commercially available angle of attack system, 20 pilots performed normal and emergency procedures during the circuit/pattern in a light aircraft. Experimental results have shown that pilot performance was improved when angle of attack was displayed in the cockpit for normal and emergency procedures during the approach phase of flight in the pattern/circuit. In relation to pilot workload, results indicated that during the approach phase of flight, there was a moderate but tolerable increase in pilot workload. The use of such a display may assist pilots to maintain the aircraft within the optimum range and hence reduce occurrences of unstable approaches. Overall, fewer stall events were observed when angle of attack was displayed and appropriate pilot decisions made during emergencies. These results provide a new perspective on pilot workload and aviation safety

Characterization of an Axially Sampling Time-of-flight Mass Spectrometer for Upper Atmospheric Measurements

The mesosphere/lower thermosphere (MLT) lies between the turbulent mixing and diffusive layers of the earth’s upper atmosphere. Temperatures in this region are varied and include the coldest region of the earth’s atmosphere, the mesopause. Too high for aircraft and too low for satellites, the only method of direct access to the MLT is by sounding rocket for periods of at most a few minutes. Because of this, the MLT is the most difficult region of the earth’s atmosphere to access and is therefore the least understood region of the earth’s atmosphere. Accurate in-situ measurements of MLT species are important for the following reasons: •CO2 concentration profiles collected in-situ will be useful in validating and improving atmospheric temperature measurements made by satellite based instruments, for example, the Sounding of the Atmosphere using Broadband Emission Radiometry on the TIMED spacecraft. • Study the transport of atmospheric species near the turbopause region. For example, NO, which is thought to be linked to ozone depletion in the stratosphere • In-situ concentration data will help to improve atmospheric models, such as the MSIS model We present an axially-sampling time-of-flight mass spectrometer (TOF-MS) suitable for deployment aboard sounding rockets to make measurements in the MLT. Use of a Bradbury- Nielsen gate to modulate ions makes on-axis sampling possible. The TOF-MS also employs a pressure tolerant microchannel plate (MCP) detector capable of operating at pressures into the 10-4 torr range. We have built and are currently testing a prototype instrument in our ion optics facility. Experiments to date demonstrate the potential of the TOF-MS to successfully make measurements in the MLT and thereby improve our knowledge of this important region of the earth’s atmosphere

Guidance, Navigation, and Control for NASA Lunar Pallet Lander

The NASA Lander Technology project is leading the development and integration of the Lunar Pallet Lander (LPL) concept. The objective is to demonstrate precision landing by delivering a payload to the lunar surface within 100 meters of a landing target. Potential landing sites are selected near the lunar pole where water may be present in permanently shadowed regions that could enable future in-situ resource utilization. The LPL is part of a sequence of missions aimed at maturing the necessary technologies, such as lunar precision landing sensors, that will enable the next generation of multi-ton lunar payloads and human landers. This paper provides an overview of the Mission Design, Guidance Navigation and Control (GNC) algorithms, and sensor suite. The results show the LPL simulated trajectory and landing precision performance under nominal and dispersed conditions. The landing precision simulation confirms the need to rely on high-accuracy navigation techniques and sensors such as Terrain Relative Navigation (TRN) and the Navigation Doppler Lidar (NDL), currently being developed for space applications. The results also demonstrate the ability of the guidance and control system to perform a soft lunar touchdown by combining thrust vector control during the solid rocket motor deceleration phase, and pulse engine control, for the liquid powered descent phase

A New Mass Spectrometer for Upper Atmospheric Measurements in the Auroral Region

We have previously presented a new rocket-borne time-of-flight mass spectrometer (TOF-MS) for measurements in the mesosphere / lower thermosphere (MLT). Traditionally, mass spectrometry in the MLT has been difficult, mainly due to the elevated ambient pressures of the MLT and high speeds of a sounding rocket flight, which affect the direct sampling of the ambient atmosphere and spatial resolution. The TOF-MS is a versatile, inherently adaptable, axial-sampling instrument, capable of operating in a traditional TOF mode or in a multiplexing Hadamard-transform mode where high spatial resolution is desired. To minimize bow shock effects at low altitudes (~70-110km), the ram surface of the TOF-MS can be cryogenically cooled using liquid He to adsorb impinging gas particles. The vacuum pumping system for the TOF-MS is tailored to the specific mission and instrument configuration. Depending on the instrument gas load and operating altitude, cryo, miniature turbo pump or getter-based pumping systems may be employed. Terrestrial TOF-MS instruments often employ a reflectron, essentially an ion-mirror, to improve mass resolving power and compensate for the thermal velocity distribution of particles being measured. The TOF-MS can be arranged in either a simple linear or reflectron configuration. Simulations and modeling are used to compare instrument mass resolution for linear and reflectron configurations for several variable conditions including vehicle velocity and ambient temperature, ultimately demonstrating the potential to make rocket-borne mass spectrometry measurements with unit-mass resolution up to at least 48 amu. Preliminary analyses suggest that many species of interest (including He, CO2, O2, O2 , N2, N2 , and NO ) can be measured with an uncertainty below 10% relative standard deviation on a sounding rocket flight. We also present experimental data for a laboratory prototype linear TOF-MS. Experimental data is compared to simulation and modeling efforts to validate and confirm instrument performance and capability. Two proposed rocket campaigns for investigations of the auroral region include the TOF-MS. By making accurate composition measurements of the neutral atmosphere from 70 to 120km, Mass Spectrometry of the Turbopause Region (MSTR) aims to improve the accuracy of temperature measurements in the turbopause region, improve the MSIS model atmosphere and examine the transition from the turbulently mixed lower atmosphere to the diffusive equilibrium of the upper atmosphere. The ROCKet-borne STorm Energetics of Auroral Dosing in the E-region (ROCK-STEADE) mission will study energy transfer in the E-region during an aurora by examining auroral emissions and measuring concentrations of neutrals and ions. The instrument suite for ROCK-STEADE includes two mass spectrometers, one each to measure neutrals and ions in the altitude range of 70 - 170km. The ability of the TOF-MS instrument to make accurate measurements will greatly aid in better understanding the MLT

Developing evaluation standards and assessing evaluation quality

The article explains the rationale for the development of standards for evaluation practice, the process followed in developing those standards, and how those standards inform the quality assessment of evaluations. Quality assessment of evaluations are conducted as a routine activity of the South African National Evaluation System (NES). The importance of quality assessment for improving the state of evaluation practice in South Africa is illustrated by presenting results from the quality assessments undertaken to date. The paper concludes by discussing the progress on the development of a public Evaluations Repository to manage and provide access to completed evaluations and their quality assessment results, and offering some concluding analytical remarks