8,426 research outputs found

    Ge(Li) data reduction using small computers

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    The advantages and limitations of using a small computer to analyze Ge(Li) radiation spectra are studied. The computer has to: (1) find the spectrum peaks, (2) determine the count rate in the photopeaks, and (3) relate the count rate to known gamma transitions to find the amount of each radionuclide present. Results show that tasks one and two may be done by the computer but task three must be done by an experimenter or a larger computer

    A data collection scheme for identification of parameters in a driver model

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    A high gain steering controller to compensate for limitations in a handicapped driver's range of motion is employed when adapting vehicle to his use. A driver/vehicle system can become unstable as vehicle speed is increased, therefore it is desirable to use a computer simulation of the driver/vehicle combination as a design tool to investigate the system response prior to construction of a controller and road testing. Unknown driver parameters must be identified prior to use of the model for system analysis. A means to collect the data necessary for identification of these driver model parameters without extensive instrumentation of a vehicle to measure and record vehicle states is addressed. Initial tests of the procedure identified all of the driver parameters with errors of 6% or less

    Judicial Sanctions and Legislative Redistricting in Washington State

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    This case study of the impact of Baker v. Carr on the State of Washington attempts to discern the nature of the role of the judiciary in the implementation of new reapportionment rules. Redistricting is usually thought of as a highly political area, outside the normal involvement of courts. Now that federal judges are under a mandate to consider the problems in this area, it is important to understand the capacity of the judicial system to discharge its role. By exercising their power with restraint, the federal judges in Washington sought to influence the political system to do its duty without an open confrontation betwden the federal judiciary and the state legislature. The author concludes that the actions taken by the federal judges were a necessary condition for redistricting in Washington in 1965. His insights into the political decision-making process may have immediate value as the 1971 legislature faces its constitutional duty to redistrict the state

    A Comparison of Vertical Ground Reaction Forces in Single-leg Jump Take-offs and Double-leg Jump Take-offs in Indoor Collegiate Volleyball Players

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    The purpose of this study was to determine if differences in vertical ground reaction forces (vGRFs) exist between single-leg take-off approaches (SL) and double-leg take-off approaches (DL) and if sex or positional differences existed in vGRFs in SL- or DL-style approaches. It was hypothesized that DL jumps would generate greater vGRFs, males would generate greater vGRFs in both styles, and middle blockers would have higher SL vGRFs while pin hitters would have higher DL vGRFs. Nine collegiate volleyball players (4 female; 5 male) (age: 20.44 ± 1.42 years; height: 186.02 ± 6.44 cm; body mass: 78.21 ± 10.63kg; body fat: 11.66 ±5.62%) were tested. An AMTI force plate collected vGRFs with three recorded trials per approach style per subject with randomization of jump-style order. The level of significance was set at p\u3c 0.05. No significant differences were found between vGRFs and position or SL and DL vGRFs. Males had significantly higher vGRFs overall compared to females (p=0.007). Male SL vGRFs were significantly larger than females (p=0.017). DL, relative SL, and relative DL vGRFs were not significantly different between genders. Height, mass, and body fat percentage had at least moderate correlations to combined vGRFs, and height moderately correlated to DL vGRFs. These results suggest that both takeoffs have similar enough force load to be interchangeable. Strength coaches may use both styles to train their athletes and improve neural integration. Positional jump loads during practice or games may be tracked interchangeably in style regarding the take-off phase

    Turning off the Lights: How Dark is Dark Matter?

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    We consider current observational constraints on the electromagnetic charge of dark matter. The velocity dependence of the scattering cross-section through the photon gives rise to qualitatively different constraints than standard dark matter scattering through massive force carriers. In particular, recombination epoch observations of dark matter density perturbations require that ϵ\epsilon, the ratio of the dark matter to electronic charge, is less than 10−610^{-6} for mX=1GeVm_X = 1 GeV, rising to ϵ<10−4\epsilon < 10^{-4} for mX=10TeVm_X = 10 TeV. Though naively one would expect that dark matter carrying a charge well below this constraint could still give rise to large scattering in current direct detection experiments, we show that charged dark matter particles that could be detected with upcoming experiments are expected to be evacuated from the Galactic disk by the Galactic magnetic fields and supernova shock waves, and hence will not give rise to a signal. Thus dark matter with a small charge is likely not a source of a signal in current or upcoming dark matter direct detection experiments.Comment: 19 pages, 2 figures; v2 - figures fixed, references adde

    Ignition characteristics of the iron-based alloy UNS S66286 in pressurized oxygen

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    The development of ignition and combustion in pressurized oxygen atmospheres was studied for the iron based alloy UNS S66286. Ignition of the alloy was achieved by heating the top surface of a cylindrical specimen with a continuous-wave CO2 laser. Two heating procedures were used. In the first, laser power was adjusted to maintain an approximately linear increase in surface temperature. In the second, laser power was periodically increased until autoheating (self-heating) was established. It was found that the alloy would autoheat to destruction from temperatures below the solidus temperature. In addition endothermic events occurred as the alloy was heated, many at reproducible temperatures. Many endothermic events occurred prior to abrupt increases in surface temperature and appeared to accelerate the rate of increase in specimen temperature to rates greater than what would be expected from increased temperature alone. It is suggested that the source of these endotherms may increase the oxidation rate of the alloy. Ignition parameters are defined and the temperatures at which these parameters occur are given for the oxygen pressure range of 1.72 to 13.8 MPa (25 to 2000 psia)

    Ignition characteristics of the nickel-based alloy UNS N07718 in pressurized oxygen

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    The development of ignition and combustion in pressurized oxygen atmospheres was studied for the nickel based alloy UNS N07718. Ignition of the alloy was achieved by heating the top. It was found that the alloy would autoheat to destruction from temperatures below the solidus temperature. In addition, endothermic events occurred as the alloy was heated, many at reproducible temperatures. Many endothermic events occurred prior to abrupt increases in surface temperature and appeared to accelerate the rate of increase in specimen temperature. It appeared that the source of some endotherms may increase the oxidation rate of the alloy. Ignition parameters are defined and the temperatures at which these parameters occur are given for the oxygen pressure range of 1.72 to 13.8 MPa (250 to 2000 psia)

    New Zealand Agribusiness Success: An Approach to exploring the role of strategy, structure and conduct on firm performance

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    This paper presents a framework to explore agribusiness success in New Zealand. The framework provides the basis for historical analysis. It draws on existing theory based on the structure-conduct-performance paradigm but expanded to take account of firm strategy and the analysis of value chains.Agribusiness, structure, conduct, performance, history, Agribusiness,

    Microstrip superconducting quantum interference device amplifiers with submicron Josephson junctions: enhanced gain at gigahertz frequencies

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    We present measurements of an amplifier based on a dc superconducting quantum interference device (SQUID) with submicron Al-AlOx-Al Josephson junctions. The small junction size reduces their self-capacitance and allows for the use of relatively large resistive shunts while maintaining nonhysteretic operation. This leads to an enhancement of the SQUID transfer function compared to SQUIDs with micron-scale junctions. The device layout is modified from that of a conventional SQUID to allow for coupling signals into the amplifier with a substantial mutual inductance for a relatively short microstrip coil. Measurements at 310 mK exhibit gain of 32 dB at 1.55 GHz.Comment: Version with high resolution figures at: http://physics.syr.edu/~bplourde/bltp-publications.ht

    A Population-Based Surveillance Study of Shared Genotypes of Escherichia coli Isolates from Retail Meat and Suspected Cases of Urinary Tract Infections.

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    There is increasing evidence that retail food may serve as a source of Escherichia coli that causes community-acquired urinary tract infections, but the impact of this source in a community is not known. We conducted a prospective, population-based study in one community to examine the frequency of recovery of uropathogenic E.&nbsp;coli genotypes from retail meat samples. We analyzed E.&nbsp;coli isolates from consecutively collected urine samples of patients suspected to have urinary tract infections (UTIs) at a university-affiliated health service and retail meat samples from the same geographic region. We genotyped all E.&nbsp;coli isolates by multilocus sequence typing (MLST) and tested them for antimicrobial susceptibility. From 2016 to 2017, we cultured 233 E.&nbsp;coli isolates from 230 (21%) of 1,087 urine samples and 177 E.&nbsp;coli isolates from 120 (28%) of 427 retail meat samples. Urine samples contained 61 sequence types (STs), and meat samples had 95 STs; 12 STs (ST10, ST38, ST69, ST80, ST88, ST101, ST117, ST131, ST569, ST906, ST1844, and ST2562) were common to both. Thirty-five (81%) of 43 meat isolates among the 12 STs were from poultry. Among 94 isolates in the 12 STs, 26 (60%) of 43 retail meat isolates and 15 (29%) of 51 human isolates were pan-susceptible (P &lt; 0.005). We found that 21% of E.&nbsp;coli isolates from suspected cases of UTIs belonged to STs found in poultry. Poultry may serve as a possible reservoir of uropathogenic E. coli (UPEC). Additional studies are needed to demonstrate transmission pathways of these UPEC genotypes and their food sources.IMPORTANCE Community-acquired urinary tract infection caused by Escherichia coli is one of the most common infectious diseases in the United States, affecting approximately seven million women and costing approximately 11.6 billion dollars annually. In addition, antibiotic resistance among E. coli bacteria causing urinary tract infection continues to increase, which greatly complicates treatment. Identifying sources of uropathogenic E. coli and implementing prevention measures are essential. However, the reservoirs of uropathogenic E. coli have not been well defined. This study demonstrated that poultry sold in retail stores may serve as one possible source of uropathogenic E. coli This finding adds to a growing body of evidence that suggests that urinary tract infection may be a food-borne disease. More research in this area can lead to the development of preventive strategies to control this common and costly infectious disease
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