Evaluation of fasteners and fastener materials for space vehicles

Testing of fasteners, bolts, rivets, and fastener materials - high temperature alloy

Campus Shootings: Does Religious Faith and Relationship with Victims Affect Psychological Well-Being?

Active shooting incidents have become an increasing public safety concern and have a large impact on the communities in which these traumatic events take place. However, while understanding outcomes following these incidents is relevant for mental health providers, first responders, and policy creators, little is known about outcome trajectories and coping best practices due to practical and ethical research limitations. Using hierarchical linear modeling, we examined longitudinal psychological well-being (PWB; MHI; Veit & Ware, 1983) trajectories of students before and after an active shooting incident (N = 35). Furthermore, this study focused on examining the moderating effects of strength of religious faith (SRF; Plante & Boccaccini, 1997a, b) on PWB trajectories. The number of observations in the longitudinal dataset ranged from 1 to 7 (M = 3.24; SD = 1.76) and span 24.18 months prior to the campus shooting through 24.33 months following the campus shooting. Survey data was collected in up to seven waves, surrounding students’ participation in an education abroad program: 6 months pre-departure (estimated), 2 weeks pre-departure (estimated), and re-entry intervals of 2 weeks, 3 months, 6 months, 9 months, and 12 months. Results of our study indicated that while individuals experienced fluctuations in PWB, the group data was not best explained with a linear or quadratic model as a function of time. However, before the shooting, strength of faith had a significant, inverse, effect on PWB, such that higher strength of faith was associated with lower PWB (B01 = -0.776, p = 0.003). The effect of exposure to the shooting was only observed in its interaction with aggregate strength of faith, such that following the shooting stronger faith was associated with increased PWB (B22 = .522, p = 0.057). These findings are consistent with others suggesting heterogenous outcomes around the religiosity variable. Implications from our study include the importance of assessing individuals’ possible religiosity and religious meaning-making following active shooting incidents, as well as the importance of providing mental health supports for the communities affected

Analysis of changes in leg volume parameters, and orthostatic tolerance in response to lower body negative pressure during 59 days exposure to zero gravity Skylab 3

The cardiovascular responses of the Apollo crewmen associated with postflight evaluations indicate varying decrements of orthostatic tolerance. The postflight changes indicate a slightly diminished ability to the cardiovascular system to function effectively against gravity following exposure to weightlessness. The objective of the Skylab LBNP experiments (M092) was to provide information about the magnitude and time course of the cardiovascular changes associated with prolonged periods of exposure to weightlessness. This report details the equipment, signal processing and analysis of the leg volume data obtained from the M092 experiment of the Skylab 3 Mission

FPGA Implementation of the Front-End of a DOCSIS 3.0 Receiver

The introduction of cable television (CATV) in the 1940s and 1950s has significantly influenced communications technology. Originally supplying only one-way television programming, the CATV industry recognized the potential of two-way communications. Starting with the introduction of pay-per view services in the 1980s, two-way communications over CATV networks eventually expanded into supplying internet access services. The increased demand for CATV services, and thus the increased demand for CATV equipment, has led the CATV industry to develop interoperability standards. The primary standard now used by the CATV industry is the Data Over Cable Service Specification (DOCSIS). DOCSIS defines both the upstream (data towards the CATV provider) and downstream (data towards the CATV customer) transmission channels. This includes specifications for the modulators and demodulators used in these channels. The number of manufacturers of CATV modulators and demodulators has greatly increased over the last twenty years and continues to do so. As the number of competitive CATV equipment suppliers increases, these manufacturers must look to ways to remain competitive by reducing time-to-market and costs associated with equipment design, as well as allowing their designs to be flexible so that they may adapt to the improvements in DOCSIS. In the past, manufacturers have primarily used Application Specific Integrated Circuits (ASICs) to implement digital hardware designs for CATV equipment. ASICs have a very high initial setup cost and do not allow for system modifications without a complete redesign. Recently, Field Programmable Gate Array (FPGA) technology has been introduced that allows manufacturers to both modify their designed digital hardware structures without a complete physical hardware redesign, as well as providing a reduced initial setup cost. Although in the long term, ASICs provide a cheaper alternative to FPGAs when produced in quantity, FPGAs provide quicker time-to-market in new product development and allow changes to made after initial release. This ability to change designs after release and the quicker time-to-market has led manufacturers to adopt FPGAs in new products. A critical component in the upstream channel of a DOCSIS compliant system is the Quadrature Amplitude Modulated (QAM) receiver. The data received at the QAM receiver have undergone several impairments including additive noise, timing offset, and frequency and phase mismatches between the transmitted modulated signal and the signal received at the demodulator. It is the function of the front-end of the receiver to correct for these impairments. This thesis presents methods for, and an example of, the design and implementation of a DOCSIS compliant QAM receiver front-end that corrects for timing, phase and frequency impairments experienced in the upstream communication channel when additive noise is present. The circuits presented are designed and implemented to reduce hardware costs when using FPGA technology. In addition, the circuits designed do not use proprietary logic, which gives designers more flexibility when implementing their own demodulator front-end circuitry. The FPGA implementation presented in this thesis achieves an average MER of 54.3 dB in a no-noise channel and close to 31 dB MER in a 25 dBc AWGN channel. The overall design uses 65 dedicated 18-bit by 18-bit multipliers and 2,970 bytes of RAM to implement the digital front-end of the receiver

Static and dynamic calibrations of MSFC's plug-nozzle special test section /redesigned 1967/

Calibration of plug nozzle special test sectio

Beryllium fastener technology

Program was conducted to develop, produce, and test optimum-configuration, beryllium prestressed and blind fasteners. The program was carried out in four phases - phase 1, feasibility study, phase 2, development, phase 3, evaluation of beryllium alloys, and phase 4, fabrication and testing