Dynamic gas temperature measurements using a personal computer for data acquisition and reduction

This report describes a dynamic gas temperature measurement system. It has frequency response to 1000 Hz, and can be used to measure temperatures in hot, high pressure, high velocity flows. A personal computer is used for collecting and processing data, which results in a much shorter wait for results than previously. The data collection process and the user interface are described in detail. The changes made in transporting the software from a mainframe to a personal computer are described in appendices, as is the overall theory of operation

Rayleigh Scattering Diagnostic for Measurement of Temperature and Velocity in Harsh Environments

A molecular Rayleigh scattering system for temperature and velocity measurements in unseeded flows is described. The system is capable of making measurements in the harsh environments commonly found in aerospace test facilities, which may have high acoustic sound levels, varying temperatures, and high vibration levels. Light from an argon-ion laser is transmitted via an optical fiber to a remote location where two flow experiments were located. One was a subsonic free air jet; the second was a low-speed heated airjet. Rayleigh scattered light from the probe volume was transmitted through another optical fiber from the remote location to a controlled environment where a Fabry-Perot interferometer and cooled CCD camera were used to analyze the Rayleigh scattered light. Good agreement between the measured velocity and the velocity calculated from isentropic flow relations was demonstrated (less than 5 m/sec). The temperature measurements, however, exhibited systematic errors on the order of 10-15%

Circuit for Communication Over Power Lines

Many distributed systems share common sensors and instruments along with a common power line supplying current to the system. A communication technique and circuit has been developed that allows for the simple inclusion of an instrument, sensor, or actuator node within any system containing a common power bus. Wherever power is available, a node can be added, which can then draw power for itself, its associated sensors, and actuators from the power bus all while communicating with other nodes on the power bus. The technique modulates a DC power bus through capacitive coupling using on-off keying (OOK), and receives and demodulates the signal from the DC power bus through the same capacitive coupling. The circuit acts as serial modem for the physical power line communication. The circuit and technique can be made of commercially available components or included in an application specific integrated circuit (ASIC) design, which allows for the circuit to be included in current designs with additional circuitry or embedded into new designs. This device and technique moves computational, sensing, and actuation abilities closer to the source, and allows for the networking of multiple similar nodes to each other and to a central processor. This technique also allows for reconfigurable systems by adding or removing nodes at any time. It can do so using nothing more than the in situ power wiring of the system

Apparatus and Method for Communication over Power Lines

An apparatus and method are provided for communicating over power lines. The apparatus includes a coupling modem that is situated between a power line and a device. The coupling modem is configured to demodulate a signal received from the power line into a sine signal and a cosine signal. The coupling modem is also configured to modulate a communicated bit stream received from the device into a transmitted signal in order to impose the transmitted signal onto the power line

Apparatus and Method for Communication over Power Lines

An apparatus and method are provided for communicating over power lines. The apparatus includes a coupling modem that is situated between a power line and a device. The coupling modem is configured to demodulate a signal received from the power line into a sine signal and a cosine signal. The coupling modem is also configured to modulate a communicated bit stream received from the device into a transmitted signal in order to impose the transmitted signal onto the power line

Two-Color Laser Speckle Shift Strain Measurement System

A two color laser speckle shift strain measurement system based on the technique of Yamaguchi was designed. The dual wavelength light output from an Argon Ion laser was coupled into two separate single-mode optical fibers (patchcords). The output of the patchcords is incident on the test specimen (here a structural fiber). Strain on the fiber, in one direction, is produced using an Instron 4502. Shifting interference patterns or speckle patterns will be detected at real-time rates using 2 CCD cameras with image processing performed by a hardware correlator. Strain detected in fibers with diameters from 21 microns to 143 microns is expected to be resolved to 15 mu epsilon. This system was designed to be compact and robust and does not require surface preparation of the structural fibers

Low Earth Orbit Space Environment Testing of Extreme Temperature 6H-SiC JFETs on the International Space Station

This paper reports long-term electrical results from two 6H-SiC junction field effect transistors (JFETs) presently being tested in Low Earth Orbit (LEO) space environment on the outside of the International Space Station (ISS). The JFETs have demonstrated excellent functionality and stability through 4600 hours of LEO space deployment. Observed changes in measured device characteristics tracked changes in measured temperature, consistent with wellknown JFET temperature-dependent device physics

K/DOQI Clinical Practice Guidelines on Hypertension and Antihypertensive Agents in Chronic Kidney Disease

INTRODUCTION: CHRONIC KIDNEY disease (CKD) is a worldwide public health issue. In the United States, there is a rising incidence and prevalence of kidney failure (Fig 1), with poor outcomes and high cost. The prevalence of earlier stages of CKD is approximately 100 times greater than the prevalence of kidney failure, affecting almost 11% of adults in the United States. There is growing evidence that some of the adverse outcomes of CKD can be prevented or delayed by preventive measures, early detection, and treatment. Hypertension is a cause and complication of CKD. Hypertension in CKD increases the risk of important adverse outcomes, including loss of kidney function and kidney failure, early development and accelerated progression of cardiovascular disease (CVD), and premature death. In the ongoing effort to improve outcomes of CKD, the National Kidney Foundation (NKF) Kidney Disease Outcomes Quality Initiative (K/DOQI) appointed a Work Group and an Evidence Review Team in 2001 to develop clinical practice guidelines on hypertension and use of antihypertensive agents in CKD. During this same time, clinical practice guidelines on this topic relevant to CKD were also under development by other organizations, including the Seventh Report of the Joint National Committee on the Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) and the 2003 report of the American Diabetes Association (ADA) on the Treatment of Hypertension in Adults with Diabetes. The Work Group maintained contact with these organizations during development of these guidelines. The purpose of the Executive Summary is to provide a "stand-alone" summary of the background, scope, methods, and key recommendations, as well as the complete text of the guideline statements. Most tables and figures in the Executive Summary are taken from other sections of the document. BACKGROUND: Chronic Kidney Disease: Figure 2 is a conceptual model of CKD, which defines stages of CKD, as well as antecedent conditions, outcomes, risk factors for adverse outcomes, and actions to improve outcomes. CKD is defined as kidney damage, as confirmed by kidney biopsy or markers of damage, or glomerular filtration rate (GFR