Description of Liquid Nitrogen Experimental Test Facility

The Liquid Nitrogen Test Facility is a unique test facility for ground-based liquid nitrogen experimentation. The test rig consists of an insulated tank of approximately 12.5 cubic ft in volume, which is supplied with liquid nitrogen from a 300 gal dewar via a vacuum jacketed piping system. The test tank is fitted with pressure and temperature measuring instrumentation, and with two view ports which allow visual observation of test conditions. To demonstrate the capabilities of the facility, the initial test program is briefly described. The objective of the test program is to measure the condensation rate by injecting liquid nitrogen as a subcooled spray into the ullage of a tank 50 percent full of liquid nitrogen at saturated conditions. The condensation rate of the nitrogen vapor on the subcooled spray can be analytically modeled, and results validated and corrected by experimentally measuring the vapor condensation on liquid sprays

Salmonella Infection After Craniotomy.

Salmonella is an uncommon cause of meningitis, especially after neurosurgery. Here, we present a case of Salmonella meningitis after craniotomy, likely due to physical contact with a snake after surgery, with contiguous spread from the patient's hand to her wound. The purpose of this report is to serve as a reminder that patients undergoing neurosurgery should avoid contact with pets, including snakes and other reptiles, in the postoperative period and practice good hand hygiene

Characterisation of High Current Density Resonant Tunneling Diodes for THz Emission Using Photoluminescence Spectroscopy

We discuss the numerical simulation of high current density InGaAs/AlAs/InP resonant tunneling diodes with a view to their optimization for application as THz emitters. We introduce a figure of merit based upon the ratio of maximum extractable THz power and the electrical power developed in the chip. The aim being to develop high efficiency emitters as output power is presently limited by catastrophic failure. A description of the interplay of key parameters follows, with constraints on strained layer epitaxy introduced. We propose an optimized structure utilizing thin barriers paired with a comparatively wide quantum well that satisfies strained layer epitaxy constraints

Simulation of Laminated Object Manufacturing (LOM) with Variation of Process Parameters

A previously developed and verified thermal model for Laminated Object Manufacturing (LOM) was used to investigate the effects of various processing parameters on the temperature profile in a LOM part during the build cycle. The mathematical model, based on 3-dimensional transient heat conduction in a rectangular geometry LOM part, allows calculation ofthe transient temperature distribution within the part during the application of a new layer as well as during other periods ofthe LOM build cycle. The parameters roller temperature, roller speed, chamber air temperature, base plate temperature, and laser cutting time were independently varied, and the LOM process response simulated. The results were analyzed in order to gain insight into potential strategies for intelligent process control.Mechanical Engineerin

Health Coverage Expansion in California: What Can Consumers Afford to Spend?

Analyzes Californians' current spending on insurance premiums and out-of-pocket expenditures to assess whether proposals to make obtaining health insurance mandatory include sufficient measures to make it affordable for low- and middle-income families

Space Shuttle Orbiter Atlantis Liquid Oxygen Prevalve Detent Roller Cracking Investigation

During routine inspections of the Space Shuttle's Main Propulsion System (MPS) Liquid Oxygen (LO2) pre-valve, the mechanism provided to maintain the valve in the open position was found cracked. The mechanism is a Vespel roller held against the valve visor by a stack of Belleville springs. The roller has been found cracked 3 times. All three instances were in the same valve in the same location. There are 6 pre-valves on each orbiter, and only one has exhibited this problem. Every-flight inspections were instituted and the rollers were found to be cracked after only one flight. Engineers at Marshall Space Flight Center, Johnson Space Center and Kennedy Space Center worked together to determine a solution. There were several possible contributors to the failure: a mis-aligned visor, an out of specification edge with a sharp radius, an out of specification tolerance stack up of a Belleville spring stack that caused un-predicted loads on the Vespel SP-21 roller, and a dimple machined into the side of the roller to indicate LO2 compatibility that created a stress riser. The detent assembly was removed and replaced with parts that were on the low-side of the tolerance stack up to eliminate the potential for high loads on the detent roller. After one flight, the roller was inspected and showed fewer signs of wear and no cracks

The Acute Effects of Whole Body Vibration on Muscular Power and Agility

Context: While research suggests whole body vibration (WBV) positively affects measures of neuromuscular performance in athletes, researchers have yet to address appropriate and effective vibration protocols. Objective: To identify the acute effects of continuous and intermittent WBV on muscular power and agility in recreationally active females. Design: We used a randomized 3-period cross-over design to observe the effects of 3 vibration protocols on muscular power and agility. Setting: Sports Science and Medicine Research Laboratory at Florida International University. Patients or Other Participants: Eleven recreationally active female volunteers (age=24.4±5.7y; ht=166.0±10.3cm; mass=59.7±14.3kg). Interventions: Each session, subjects stood on the Galileo WBV platform (Orthometrix, White Plains, NY) and received one of three randomly assigned vibration protocols. Our independent variable was vibration length (continuous, intermittent, or no vibration). Main Outcome Measures: An investigator blinded to the vibration protocol measured muscular power and agility. We measured muscular power with heights of squat and countermovement jumps. We measured agility with the Illinois Agility Test. Results: Continuous WBV significantly increased SJ height from 97.9±7.6cm to 98.5±7.5cm (P=0.019, β=0.71, η2 =0.07) but not CMJ height [99.1±7.4cm pretest and 99.4±7.4cm posttest (P=0.167, β=0.27)] or agility [19.2±2.1s pretest and 19.0±2.1s posttest (P=0.232, β=0.21)]. Intermittent WBV significantly enhanced SJ height from 97.6±7.7cm to 98.5±7.7cm (P=0.017, β=0.71, η2 =0.11) and agility 19.4±2.2s to 19.0±2.1s (P=0.001, β=0.98, η2=0.16), but did not effect CMJ height [98.7±7.7cm pretest and 99.3±7.3cm posttest (P=0.058, β=0.49)]. Conclusion: Continuous WBV increased squat jump height, while intermittent vibration enhanced agility and squat jump height. Future research should continue investigating the effect of various vibration protocols on athletic performance

Aspirations and common tensions : larger lessons from the third US national climate assessment

Author Posting. © The Author(s), 2015. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Climatic Change 135 (2016): 187-201, doi:10.1007/s10584-015-1530-z.The Third US National Climate Assessment (NCA3) was produced by experts in response to the US Global Change Research Act of 1990. Based on lessons learned from previous domestic and international assessments, the NCA3 was designed to speak to a broad public and inform the concerns of policy- and decision-makers at different scales. The NCA3 was also intended to be the first step in an ongoing assessment process that would build the nation’s capacity to respond to climate change. This concluding paper draws larger lessons from the insights gained throughout the assessment process that are of significance to future US and international assessment designers. We bring attention to process and products delivered, communication and engagement efforts, and how they contributed to the sustained assessment. Based on areas where expectations were exceeded or not fully met, we address four common tensions that all assessment designers must confront and manage: between (1) core assessment ingredients (knowledge base, institutional set-up, principled process, and the people involved), (2) national scope and subnational adaptive management information needs, (3) scope, complexity, and manageability, and (4) deliberate evaluation and ongoing learning approaches. Managing these tensions, amidst the social and political contexts in which assessments are conducted, is critical to ensure that assessments are feasible and productive, while its outcomes are perceived as credible, salient, and legitimate