Equilibrium States of Liquid, Solid, and Vapor and the Configurations for Copper, Tungsten, and Pores in Liquid-Phase Sintering

The equilibrium state of the liquid-solid structure during liquid-phase sintering (LPS) is pondered with respect to minimum energy geometries. Besides the solid-liquid ratio, several interfacial energies determine the most stable geometric configuration. In this study, we rely on the attributes of the copper or nickel as the liquid, tungsten as the solid, and vapor to solve for terminal configurations that include liquid pools inside the solid grains. Surface evolution is enabled using a stepwise computer program[1] to rearrange and reshape small grain clusters reflective of LPS based on a preset combination of wetting and dihedral angles. The findings show how different interfacial energies, as a result of oxidation or impurity segregation, play a role in determining the final geometry. The specific concern is identification of situations in which a liquid is stable inside the solid, as observed in some LPS materials.open112Nsciescopu

Description of the three axis low-g accelerometer package

The three axis low-g accelerometer package designed for use on the Space Processing Application Rocket (SPAR) Program is described. The package consists of the following major sections: (1) three Kearfott model 2412 accelerometers mounted in an orthogonal triad configuration on a temperature controlled, thermally isolated cube, (2) the accelerometer servoelectronics (printed circuit cards PC-6 through PC-12), and (3) the signal conditioner (printed circuit cards PC-15 and PC-16). The measurement range is 0 + or - 0.031 g with a quantization of 1.1 x 10 to the 7th power g. The package was flown successfully on six SPAR launches with the Black Brant booster. These flights provide approximately 300 s of free fall or zero-g environment

Novel Space-based Solar Power Technologies and Architectures for Earth and Beyond

Research, development and studies of novel space-based solar power systems, technologies and architectures for Earth and beyond are needed to reduce the cost of clean electrical power for terrestrial use and to provide a stepping stone for providing an abundance of power in space, i.e., manufacturing facilities, tourist facilities, delivery of power between objects in space, and between space and surface sites. The architectures, technologies and systems needed for space to Earth applications may also be used for in-space applications. Advances in key technologies, i.e., power generation, power management and distribution, power beaming and conversion of beamed power are needed to achieve the objectives of both terrestrial and extraterrestrial applications. Power beaming or wireless power transmission (WPT) can involve lasers or microwaves along with the associated power interfaces. Microwave and laser transmission techniques have been studied with several promising approaches to safe and efficient WPT identified. These investigations have included microwave phased array transmitters, as well as laser transmission and associated optics. There is a need to produce "proof-of-concept" validation of critical WPT technologies for both the near-term, as well as far-term applications. Investments may be harvested in near-term beam safe demonstrations of commercial WPT applications. Receiving sites (users) include ground-based stations for terrestrial electrical power, orbital sites to provide power for satellites and other platforms, future space elevator systems, space vehicle propulsion, and space to surface sites. This paper briefly discusses achieving a promising approach to the solar power generation and beamed power conversion. The approach is based on a unique high-power solar concentrator array called Stretched Lens Array (SLA) for both solar power generation and beamed power conversion. Since both versions (solar and laser) of SLA use many identical components (only the photovoltaic cells need to be different), economies of manufacturing and scale may be realized by using SLA on both ends of the laser power beaming system in a space solar power application. Near-term uses of this SLA-laser-SLA system may include terrestrial and space exploration in near Earth space. Later uses may include beamed power for bases or vehicles on Mars

Development of Lunar Highland REgolith Simulants, NU-LHT-1M,-2M

As part of a collaborative agreement between the U.S, Geological Survey (USGS) and NASA's Marshall Space Flight Center (MSFC) lunar highland simulants are being produced to support engineers and scientists in developing the technologies required to put a base on the moon by 2024. Two simulants have been produced to date: NU-LHT-1M and -2M (NASA/USGS-Lunar Highlands Type-l & 2 Medium-grained). Using starting material chiefly collected from the Stillwater Mine, Nye, MT, blending protocols were developed based on normative mineralogy calculated from average chemistry, for the Apollo 16 regolith. New technologies using a high temperature remotely coupled plasma melter were developed to generate both high quality and agglutinitic glasses that simulate the glassy components of the regolith. Detailed chemical, mineralogical and physical properties analysis of NU-LHT-1M indicate that it is overall a good surrogate for highlands lunar regolith (our new simulant LHT-2M has not be analyzed yet). The primary difference between 1M and 2M was the inclusion of trace mineralogy (phosphates and sulfide). Plans will also be presented on the future direction of the simulant project

NASA Lunar Regolith Simulant Program

Lunar regolith simulant production is absolutely critical to returning man to the Moon. Regolith simulant is used to test hardware exposed to the lunar surface environment, simulate health risks to astronauts, practice in situ resource utilization (ISRU) techniques, and evaluate dust mitigation strategies. Lunar regolith simulant design, production process, and management is a cooperative venture between members of the NASA Marshall Space Flight Center (MSFC) and the U.S. Geological Survey (USGS). The MSFC simulant team is a satellite of the Dust group based at Glenn Research Center. The goals of the cooperative group are to (1) reproduce characteristics of lunar regolith using simulants, (2) produce simulants as cheaply as possible, (3) produce simulants in the amount needed, and (4) produce simulants to meet users? schedules

Lunar Regolith Simulant User's Guide

Based on primary characteristics, currently or recently available lunar regolith simulants are discussed from the perspective of potential experimental uses. The characteristics used are inherent properties of the material rather than their responses to behavioral (geomechanical, physiochemical, etc.) tests. We define these inherent or primary properties to be particle composition, particle size distribution, particle shape distribution, and bulk density. Comparable information about lunar materials is also provided. It is strongly emphasized that anyone considering either choosing or using a simulant should contact one of the members of the simulant program listed at the end of this document

From Lunar Regolith to Fabricated Parts: Technology Developments and the Utilization of Moon Dirt

The U.S. Space Exploration Policy has as a cornerstone the establishment of an outpost on the moon. This lunar outpost wil1 eventually provide the necessary planning, technology development, testbed, and training for manned missions in the future beyond the Moon. As part of the overall activity, the National Aeronautics and Space Administration (NASA) is investigating how the in situ resources can be utilized to improve mission success by reducing up-mass, improving safety, reducing risk, and bringing down costs for the overall mission. Marshall Space Flight Center (MSFC), along with other NASA centers, is supporting this endeavor by exploring how lunar regolith can be mined for uses such as construction, life support, propulsion, power, and fabrication. An infrastructure capable of fabrication and nondestructive evaluation will be needed to support habitat structure development and maintenance, tools and mechanical parts fabrication, as well as repair and replacement of space-mission hardware such as life-support items, vehicle components, and crew systems, This infrastructure will utilize the technologies being developed under the In Situ Fabrication and Repair (ISFR) element, which is working in conjunction with the technologies being developed under the In Situ Resources Utilization (ISRU) element, to live off the land. The ISFR Element supports the Space Exploration Initiative by reducing downtime due to failed components; decreasing risk to crew by recovering quickly from degraded operation of equipment; improving system functionality with advanced geometry capabilities; and enhancing mission safety by reducing assembly part counts of original designs where possible. This paper addresses the need and plan for understanding the properties of the lunar regolith to determine the applicability of using this material in a fabrication process. This effort includes the development of high fidelity simulants that will be used in fabrication processes on the ground to drive down risk and increase the Technology Readiness Level (TRL) prior to implementing this capability on the moon. Also discussed in this paper is the on-going research using Electron Beam Melting (EBM) technology as a possible solution to manufacturing parts and spares on the Moon's surface

Deductive synthesis of recursive plans in linear logic

Linear logic has previously been shown to be suitable for describing and deductively solving planning problems involving conjunction and disjunction. We introduce a recursively defined datatype and a corresponding induction rule, thereby allowing recursive plans to be synthesised. In order to make explicit the relationship between proofs and plans, we enhance the linear logic deduction rules to handle plans as a form of proof term

Using FSRs to measure radial pressure in wound rolls

The Force Sensing Resistor (FSRTM)1 is a device which changes resistance in a predictable manner with the application of force on its surface.[1] The FSR has been used in a variety of applications since its invention in 1986, including position sensing, traffic counting, pressure sensing in wind tunnels and sensing in numerous security devices. This publication presents the results of a study in which the FSR was implemented as a tool for measuring the radial interlayer pressures in wound rolls.The FSR exists in two primary forms: the shunt mode FSR, and the through conduction mode FSR. The focus of this study is concentrated entirely upon the shunt mode form of the device. The term "FSR" will refer to this form of the device throughout this publication.The FSR consists of two polyester sheets sandwiched together. One sheet contains a screen printed pattern of discontinuous conductive fingers. The other sheet contains a sensing film consisting of a number of organic and inorganic ingredients suspended in a polymer matrix. The sensing film acts as a shunt resistance to the printed conductor on the opposing polyester sheet. The shunt resistance of the sensing film decreases proportionately with the applied normal force by means of microscopic contact mechanisms in the sensing film. Very small conductors and semiconductors, ranging from fractions of microns to microns in size, are present in the sensing film. The intimate contact of these particles with other particles and with the conductive fingers on the opposite sheet produces a relatively uniform resistance that changes as a function of pressure. In Figure I, the mechanical form of the FSR is illustrated.Since the FSR is manufactured by a screen printing process, any size or shape of FSR can be manufactured. The FSR used for all of the work in this study is shown in Figure 2. This pattern can be used not only to measure interlayer pressures at various radii in the wound roll, but it can also be used to measure the pressure variations across the width of the web in the cross machine direction.This publication will first present a technique by which the FSR can be calibrated for experimental studies of the radial pressure profile in wound rolls. The results of wound roll studies which have led to the discovery of a new boundary condition for wound roll stress models are also presented. The development of this boundary condition allows models previously constrained to center-winding to be applied to center-winding with an undriven nip roll pressed against the wound roll.Mechanical and Aerospace Engineerin

Effects of Volitional Preemptive Abdominal Contraction on Shoulder Proprioception Following Shoulder Muscle Fatigue

The abdominal bracing maneuver, a volitional preemptive abdominal contraction (VPAC) strategy, is potentially beneficial to shoulder exercise performance. It is unclear how VPAC use affects shoulder function, including proprioception and shoulder muscle function following shoulder muscle fatigue caused by upper extremity dominant sports movements. Discovering methods that reduce its effects on shoulder proprioception and shoulder muscle function is important for clinical practice in orthopedic rehabilitation. PURPOSE: To identify VPAC effects on shoulder proprioception abilities and to identify VPAC effects on shoulder muscle electromyographic amplitudes, during seated proprioception trials, both with and without muscle fatigue present. METHODS: Thirty-nine participants (26 women, 13 men) participated in this study. Shoulder proprioception was measured by shoulder flexion reproduction angles. Kinematic data were collected during the shoulder flexion trials to determine the accuracy in the subjects’ ability to reproduce a reference angle. All data were collected before and after a shoulder muscle fatigue protocol. Electromyographic data from the anterior deltoid (AD), posterior deltoid (PD), upper trapezius (UT), lower trapezius (LT), serratus anterior (SA), and infraspinatus (IF) muscles were used to observe muscle contraction amplitudes during the angle reproduction trials. RESULTS: Shoulder reproduction angles were not significantly affected by VPAC or muscle fatigue. Individually, shoulder muscle fatigue significantly increased UT muscle amplitudes (Mdn = 0.059(0.135), p\u3c.008) and LT muscle amplitudes (Mdn = 0.023(0.059), p\u3c.008). VPAC significantly increased shoulder IF muscle amplitudes (Mdn = 0.019(0.038), p\u3c.008). CONCLUSION: The VPAC did not affect shoulder proprioception in this study, showing that the strategy may not be beneficial to improving proprioception in the shoulder joint. The affects of muscle fatigue on the selected shoulder muscles supported the observations in previous literature concerning muscle fatigue effects on selected shoulder muscle. Clinicians can use this information to assist with the creation of therapeutic exercise for the shoulder joint