965 research outputs found
Surface energy fluxes in complex terrain
The emphasis of the 1985 NASA project activity was on field measurements of wind data and heat balance data. Initiatives included a 19 station mountaintop monitoring program, testing and refining the surface flux monitoring systems and packing and shipping equipment to the People's Republic of China in preparation for the 1986 Tibet Experiment. Other work included more extensive analyses of the 1984 Gobi Desert and Rocky Mountain observations plus some preliminary analyses of the 1985 mountaintop network data. Details of our field efforts are summarized and results of our data analyses are presented
Measurements of SCRF cavity dynamic heat load in horizontal test system
The Horizontal Test System (HTS) at Fermilab is currently testing fully
assembled, dressed superconducting radio frequency (SCRF) cavities. These
cavities are cooled in a bath of superfluid helium at 1.8K. Dissipated RF power
from the cavities is a dynamic heat load on the cryogenic system. The magnitude
of heat flux from these cavities into the helium is also an important variable
for understanding cavity performance. Methods and hardware used to measure this
dynamic heat load are presented. Results are presented from several cavity
tests and testing accuracy is discussed.Comment: 6 pp. Cryogenic Engineering Conference and International Cryogenic
Materials Conference 28 Jun - 2 Jul 2009. Tucson, Arizon
Dynamic PID loop control
The Horizontal Test Stand (HTS) SRF Cavity and Cryomodule 1 (CM1) of eight
9-cell, 1.3GHz SRF cavities are operating at Fermilab. For the cryogenic
control system, how to hold liquid level constant in the cryostat by regulation
of its Joule-Thompson JT-valve is very important after cryostat cool down to
2.0 K. The 72-cell cryostat liquid level response generally takes a long time
delay after regulating its JT-valve; therefore, typical PID control loop should
result in some cryostat parameter oscillations. This paper presents a type of
PID parameter self-optimal and Time-Delay control method used to reduce
cryogenic system parameters' oscillation.Comment: 7 pp. Cryogenic Engineering Conference and International Cryogenic
Materials Conference CEC-ICMC 2011, 13-17 June 2011. Spokane, Washingto
Rates and Predictors of Professional Interpreting Provision for Patients With Limited English Proficiency in the Emergency Department and Inpatient Ward.
The provision of professional interpreting services in the hospital setting decreases communication errors of clinical significance and improves clinical outcomes. A retrospective audit was conducted at a tertiary referral adult hospital in Brisbane, Australia. Of 20 563 admissions of patients presenting to the hospital emergency department (ED) and admitted to a ward during 2013-2014, 582 (2.8%) were identified as requiring interpreting services. In all, 19.8% of admissions were provided professional interpreting services in the ED, and 26.1% were provided on the ward. Patients were more likely to receive interpreting services in the ED if they were younger, spoke an Asian language, or used sign language. On the wards, using sign language was associated with 3 times odds of being provided an interpreter compared with other languages spoken. Characteristics of patients including their age and type of language spoken influence the clinician's decision to engage a professional interpreter in both the ED and inpatient ward
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Comparison of a diagnostic wildfire modeling system (HIGRAD/BEHAVE) with a self-determining wildfire modeling system (HIGRAD/FIRETEC)
In this paper details of the wildfire modeling system are illustrated. First the dynamical model, HIGRAD, capable of accurately resolving regions of strong gradients, is described. Next, the two wildfire models FIRETEC and BEHAVE are introduced. Unlike the traditional point-functional approach used in the BEHAVE-like fire model, FIRETEC is a self-determining fire model. The benefits of the HIGRAD/FIRETEC approach with respect to HIGRAD/BEHAVE are shown in the results section of this paper. Two major conclusions are drawn in this section. The first conclusion is that the rate of spread of a fire to a first approximation is independent of the local wind velocity. The second conclusion is that HIGRAD/FIRETEC can be used to develop point-functions for use in HIGRAD/BEHAVE
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A Technique for Epoxy Free Winding and Assembly of COS θ Coils for Accelerator Magnets
Traditional methods of magnet construction (wet winding) use molded coil subassemblies bonded together with epoxy impregnated fiberglass tape. This is a highly labor intensive process involving redundant operations for each of the four coils. The epoxy free winding technique (dry winding) eliminates the epoxy curing steps and also allows all four coils to be wound on 3 common winding mandrel, thereby reducing winding stations and handling. The tooling required for dry winding is a radical departure from existing technology imposing new mechanical problems. A number of 64 cm long 5 cm aperture SSC Design B'' magnets have been produced at Fermilab utilizing dry winding techniques. Discussed is the specialized tooling created to accomplish dry winding as well as new winding and assembly procedures required. Also discussed are mechanical problems encountered and their solutions. Based on experience gained, dry winding can be a viable lower cost alternative to traditional coil fabrication techniques
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Mechanical support of superconducting coils
Cold iron magnets use the iron yoke and skin for mechanical support of the collared coil assembly. A variety of designs, including horizontally and vertically split yokes, collarless'' magnets and conductor block geometries, have been considered for use with collared coils. This note qualitatively compares the support mechanisms by estimating the amount of coil overcompression'' necessary for the magnet to achieve the same mechanical condition in the cold, powdered state. These designs inspect magnet limitations by suggesting means to reduce the peak coil compressive load, allowing higher central magnetic fields to be reached
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End designs for superconducting magnets
New accelerators such as the Tevatron Upgrade frequently require higher magnetic fields that have been conventionally used in superconducting magnets. Modern magnet designs often have a smaller bore diameter and wider cable than the early (e.g., Tevatron) superconducting coils and are consequently harder to wind. These developments make consideration of end winding more important. End parts must be made to confine the conductors to a consistent shape. This shape must be defined and described to both the parts manufacturers and those analyzing the magnetic field. Internal stresses in the cable must be minimized. It has therefore become necessary to reevaluate the methods used to determine the configuration of a magnetic end. This note describes those methods and attempts to apply them to possible cross sections for high field dipoles. The original Tevatron dipole end configuration is reviewed for reference. 3 refs., 10 figs., 1 tab
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Midtropospheric influences on boundary layer evolution in the Mexico City basin
Mexico City lies in a horseshoe-shaped basin at 2250 m AGL. These authors have simulated the effects of thermally-forced local to regional-scale circulation patterns on the ozone distribution within the basin. On most of the case days studied a relationship could be found between the spatial and temporal evolution of wind patterns and ozone concentration, particularly in the southwestern part of the basin. In this paper, the authors focus upon defining the relationship between the vertical structure of the atmosphere, by examining stability and wind shear, and the near surface pollution. This work was prompted by the need to better understand the role of midtropospheric flow in contributing to, or alleviating, the pollution problem in the basin. The role of vertical exchange processes in this locale has so far been only peripherally explored. From this investigation the authors hope to assess the importance of upper level winds in contributing to ventilation of pollutants out of the basin above the mountaintop level, in flushing the polluted airmass out of the basin, and in the development of basin-wide recirculation patterns. The results of preliminary data analyses are described
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