In 1982, Philippine commercial production of fish reached a record high level and achieved a substantial 6.1 percent growth in volume after several years of stagnation and dec line. Data are not yet available on the performance of small fishermen in the m...
National Technical Information Service (NTIS)
Ablation performance of glasslike carbons, pyrolytic graphite, and artificial graphite in stagnation
NASA Technical Reports Server (NTRS)
A visualization of the flow past a cylinder with and without a rear stagnation jet has been performed. Results show that the massively separated wake behind the cylinder can be completely eliminated and the flow around the cylinder behaved as inviscid flow by a rear stagnation jet with a minimum dimensionless parameter.
NASA Astrophysics Data System (ADS)
In a number of experimental and numerical publications a deviation has been found between the measured or computed stagnation point heat flux and that given by the theory of Fay and Riddell. Since the formula of Fay and Riddell is used in many applications to yield a reference heat flux for experiments performed in wind tunnels, for flight testing and ...
The growth law for the development of top athletes performances remains unknown in quantifiable sport events. Here we present a growth model for 41351 best performers from 70 track and field (T&F) and swimming events and detail their characteristics over the modern Olympic era. We show that 64% of T&F events no longer improved since 1993, while 47% ...
PubMed Central
... Title : Characterization of Pulse Detonation Engine Performance with Varying Free Stream Stagnation Pressure Levels. ...
DTIC Science & Technology
The author reports both the progress and stagnation of Hispanic education on its 25th year of Hispanic achievement. The focus is on the need to understand and address the gap in Hispanic male achievement. For the past 25 years, Chicanas consistently out-perform Chicanos at every level of schooling. Most recent ...
ERIC Educational Resources Information Center
To explore the question whether the Hall effect removes the unphysical feature of ideal magnetohydrodynamics of predicting unstable small wavelenght kinks near any elliptic magnetic stagnation line, a spectral analysis is performed of the motion of an inc...
Experimental studies were conducted to investigate the flow and the performance of thrust augmenting ejectors for flight Mach numbers in the range of 0.5 to 0.8, primary air stagnation pressures up to 107 psig (738 kPa), and primary air stagnation tempera...
-Region Heat Transfer Numerical simulations of laminar stagnation-region heat transfer in the presence on the amplification of streamwise vorticity and the associated heat transfer augmentation. In the present simulation of freestream disturbances are performed. The sensitivity of heat transfer in stagnation- region to freestream
E-print Network
The Integrated Stationary Evacuated Concentrator or ISEC solar collector has achieved the best high temperature performance ever measured with a stationary collector. A development program to carry out a design review of the initial proof of concept configuration has been completed. Changes in the optical design to improve the angular response function and ...
Energy Citations Database
A simple test rig for investigating the performance of vaneless diffusers with diverging walls for centrifugal compressors has been designed, fabricated and satisfactorily tested. The test rig was designed to give values of area ratio from 1.5 to 6 for an included angle of 10 deg. A uniform flow at the entry of the diffuser had been achieved by the use of ...
Rare tumors, when considered as a group, represent a significant burden to society as they may account for up to 25% of the mortality by cancer in nations like the United States. In contrast with the current scenario in highly incident cancer types, little progress has been achieved in the treatment of the most rare cancers. The reasons for this apparent ...
The Integrated Stationary Evacuated Concentrator or ISEC solar collector panel has achieved the best high temperature performances ever measured with a stationary collector. A development effort to carry out a review and optimization of the initial proof of concept design is nearing completion. Changes in the optical design to improve the angular response ...
A molten material assessment for O6 mixed-bundle channel feeder stagnation break in CANDU-6 reactor has been performed using CATHENA slave channel model. The feeder stagnation break size for the mixed-bundle channel is found to be the same as that for the...
Laser plasma drag reduction is a new method to reduce the wave drag of hypersonic flight. Inject laser power is an important parameter. An appropriate laser power should be chosen when laser power was injected to achieve the best drag reduction effect via the minimum laser power. The effect of inject laser power on the performance of laser plasma drag ...
An experimental investigation was conducted to model the film-cooling performance for a turbine-vane
... To perform these calculations, a flux-limited non-equilibrium radiation diffusion model was incorporated into the MACH2 code. ...
Due to the irregular shapes associated with ice formations, multiple stagnation points can develop on the iced surface. This can lead to difficulty in selecting the ...
NASA Website
The present invention employs a constrained stagnation flow geometry apparatus to achieve the uniform deposition of materials or heat. The present invention maximizes uniform fluxes of reactant gases to flat surfaces while minimizing the use of reagents and finite dimension edge effects. This results, among other things, in large area continuous films that ...
DOE Information Bridge
A quasi-one-dimensional, single-fluid model is used to examine the cometosheath flow along the Sun-comet axis at comet, Halley. The effects of mass loading, dissociative recombination, magnetic field line curvature, ion-neutral drag, and flow divergence on the submagnetosonic flow in this region are discussed. In particular, the inclusion of the flow divergence, which is ...
The Integrated Stationary Evacuated Concentrator or ISEC solar collector panel has achieved the best high temperature performance ever measured with a stationary collector. A development effort to carry out a review and optimization of the initial proof of concept design has been completed. Changes in the optical design to improve the angular response ...
The Integrated Stationary Evacuated Concentrator or ISEC solar collector panel which achieved the best high temperature performance ever measured with a stationary collector was examined. A development effort review and optimize the initial proof of concept design was completed. Changes in the optical design to improve the angular response function and ...
The goal of this study was to examine to what extent the conditions of restricted input of L2 and SLI have an additive impact on language acquisition. Therefore, the Dutch language achievement of 6-, 7-, and 8-year-old bilingual children with SLI was compared with that of typically developing monolingual Dutch children, typically developing bilingual children, and monolingual ...
PubMed
A feasibility study has been made of the 'laser heated wind tunnel'. The analytical portion of the study indicates that it should be possible to achieve stagnation conditions of 10,000 degrees Kelvin and 1-2,000 atmosphere with laser powers of a few megaw...
Contents: Academic achievement; Administration and organization; Adult education; Brain drain; Courses of study (Higher education); Curriculum; Economics of education; Education--general; Educational psychology; Educational research; Educational sociology...
detonation-driven reflected-shock tunnel (RST) to achieve ... The test chamber is a 19-foot long, 7-foot diameter .... stagnation enthalpy, Mach number, and static ...
The persistence of poverty and stagnation in the Third World poses certain problems for American policymakers. Before the United States can achieve mutually cooperative relations with Third World countries, we must decide whether there are limits to growt...
Page 1. "DETERMINANTS OF READING PERFORMANCE ... DETERMINANTS OF READING PERFORMANCE AND ACHIEVEMENT' ...
An evaluation of the relative performance advantage of various ablation materials for the heat protection to a nonlifting vehicle during hypersonic reentry into the earth's atmosphere was made based on theoretical ablation models substantiated hy experiment. Calculations were also made of the heat penetration within the material. Typical ablation materials ...
Over the past several years, computational scientists have observed a frustrating trend of stagnating application performance despite dramatic increases in peak performance of high performance computers. In 2002, researchers at Lawrence Berkeley National Laboratory, Argonne National Laboratory, and IBM proposed a ...
The objective of the program is the demonstration of high performance, cost effective, non-concentrating solar collectors using heat pipes. The end product will be directly applicable for efficient use with absorption and Rankine cycle chillers. Evacuated tubular solar collectors were selected as the only economical non-concentrating approach capable of efficient operation of ...
The problem of a critical flow of two-phase mixture, boosted to a selected stagnation state and allowed to flow through a nozzle orifice into a long straight tube, is treated generically and analytically, making use of the basic laws of fluid mechanics and thermodynamics. Specific calculations have been performed using R-114 as the flowing medium. An ...
Experimental measurements of stagnation point equilibrium radiative heat transfer were performed using an arc driven shock tube facility and over the range of simulated flight velocities between 26,000 and 52,000 feet per second, and at altitudes from 100...
A preliminary experimental study of the stagnation temperature field in the laminar wake of a conical and a wedge model was made. The measurements were performed by means of a hotwire probe in a 20-in. diameter shock tunnel with a nominal free-stream Mach...
Presented at the Eight Meeting of the Supersonic Wind- Tunnel Association, Seattle, Wash., Oct. 1957. The two control systems are compared for nominal stagnation pressures of 16 and 34 psia. The improved performance of system B has resulted in increased Mach number capability of the tunnel, improved Mach number control during a run, and an ...
The report describes an experimental investigation of the effects of high stagnation pressures, extremely oxidizer-rich mixture ratios, and various injector configurations on the performance characteristics of a liquid rocket combustor. These environmenta...
Eighteen material properties were measured on 45 different, commercially available, artificial graphites. Ablation performance of these same graphites were also measured in a Mach 2 airstream at a stagnation pressure of 5.6 atm. Correlations were develope...
The performance of dry, low NOx gas turbines, which employ lean premixed (or partially premixed) combustors, is often limited by static and dynamic combustor stability, and they require complicated mixing hardware. To overcome these issues, a novel design, referred to as a Stagnation Point Reverse Flow (SPRF) combustor, has been recently demonstrated. The ...
Evacuated tubular solar collectors were selected as the only economical non-concentrating approach capable of efficient operation of chillers. The General Electric TC family of collectors was chosen because of their high level of performance and compatibility with heat pipe integration. Three heat pipe fluid-vessel combinations were identified and are continuing to be life ...
This paper describes the application of computer testing to a design study of butterfly bileaflet mitral prostheses having flat or curved leaflets. The curvature is in the plane normal to the pivot axes and is such that the convex sides of the leaflets face each other when the valve is open. The design parameters considered are the curvature of the leaflets and the location of the pivot points. In ...
The performance of both benzene (C6H6) and kerosene (C12H24) for use as fuels in air combustion driven CW gasdynamic lasers is calculated. The calculations are performed for an equivalency air-fuel ratio equal to unity and the stagnation pressure equal to 15 atm, with geometric dimensions of the lasers being optimized for maximum net ...
... funded research, testing and ... Descriptors : *TEST CONSTRUCTION( PSYCHOLOGY ... PERFORMANCE TESTS, ACHIEVEMENT TESTS, APTITUDE ...
A flow barrier disposed at the periphery of a workpiece for achieving uniform reaction across the surface of the workpiece, such as a semiconductor wafer, in a stagnation flow reactor operating under the conditions of a low pressure or low flow rate. The flow barrier is preferably in the shape of annulus and can include within the annular structure ...
Water tunnel experiments have been performed to investigate a general mechanistic model [1] for heat transfer augmentation by large scale freestream turbulence at a stagnation point. Time-resolved Digital Particle Image Velocimetry was used to measure velocity fields and calculate both integral length scale and turbulence intensity in the vicinity of the ...
We performed a numerical study to understand the dynamical mechanism controlling the formation and avalanche of a stagnant slab using two-dimensional dynamical models of the integrated plate-mantle system with freely movable subducting and overriding plates. We examined slab rheology as a mechanism for producing various styles of stagnating or penetrating ...
found that, for conditions free of such problem, the stagnation point ... models , if ? and n match at the stagnation point, they will tend to match ...
In recent years Uruguay has been undergoing a process of transition from a situation of economic stagnation to a period of moderate but steady economic growth. This turn-around in economic performance is explained by a significant change in development st...
Numerical calculations were performed using a simplified chemical kinetic mechanism to determine the structure of counterflow heptane-air diffusion flames. The configuration used is a diffusion flame stabilized in the vicinity of a stagnation plane which ...
The influence of the Lewis number on turbulent flame front geometry is investigated in a premixed turbulent stagnation point flame. A laser tomography technique is used to obtain the flame shape, a fractal analysis of the multiscale flame edges is perform...
The stagnation point flow experiment was applied to study ex-vivo blood material interactions using 29 chemically different materials supplied by NIH contractors as potential blood contact surfaces. A total of 2250 valid tests were performed under this co...
Data was obtained on the oxidative degradative behavior of a number of materials used in coal mines. Tests were performed using a stagnation burner arrangement. Materials examined included those used in typical coal mining operations such as (1) polyvinyl...
A pulse detonation engine operates on the principle that a fuel-air mixture injected into a tube will ignite and undergo a transition from a deflagration to a detonation and exit the tube at supersonic velocities. Studies in the field of combustion have s...
The objective of this research was to evaluate the feasibility of using the triggered decay of a radioactive isomer in a solid-state heat exchanger to power a gas turbine engine. Primary performance measures were stagnation temperature increase and stagna...
... determine free-field stagnation pressures and impulses produced by ... Blast waves; Stagnation pressure; Underground storage; Stagnation impulse. ...
Over the past thirty years, the modern workplace has radically changed, and the demands on those making the transition from the classroom to the workforce continue to rise. Students from Birmingham and Boston no longer compete against each other for jobs; instead, their rivals are well-educated students from Sydney and Singapore. But as globalization has progressed, American educational progress ...
The stagnation phase of a Z pinch is examined for two alternative scenarios: (i) the reflection of a dense shell off of a hot but low density core, and (ii) the expansion of a shock wave from the axis as it accretes inflowing material. The former case is characteristic of 1D Lagrangian simulations and the latter is an extension of Noh's classic problem. This problem is first ...
Mr. Brennan, president of the Bituminous Coal Operator's Association, feels that a labor relations revolution is needed in the coal industry to match the current metamorphosis of coal from a secondary industry to one of primary importance. The emerging needs of the coal industry, he says, clearly give shape to the labor relations response. Both management and labor must, first of all, be ...
Integrated experiments to investigate the ultrafast heating of implosions using cone/shell geometries have been performed at the Rutherford Appleton Laboratory. The experiments used the 1054 nm, nanosecond, 0.9 kJ output of the VULCAN Nd:glass laser to drive 486 ?m diameter, 6 ?m wall thickness Cu-doped deuterated plastic (CD) shells in 6-beam cubic symmetry. Measurements of ...
It is well known that thrombus can be formed at stagnation regions in blood flow. However, studies of thrombus formation have typically focused on steady state flow. We hypothesize that pulsating flow may reduce persistent stagnation at the sites of low shear stress by decreasing exposure time. In this study, a step-wall transition, which is commonly found ...
This study redesigned the blade leading edges of a small low-solidity axial turbine to obtain operational flexibility. Further flexibility was gained by using a low-solidity cascade, which allowed the leading edges to have a higher radius of curvature. The cascade also allowed larger flow deflections, which resulted in higher utilization factors. Because of the smaller frictional surfaces ...
... Descriptors : *ATMOSPHERES, *STAGNATION POINT, THERMAL PROPERTIES, DIFFUSION. Subject Categories : THERMODYNAMICS. ...
... (Author). Descriptors : *HEAT SHIELDS, *MAGNETOHYDRODYNAMICS, ABLATION, STAGNATION POINT, MAGNETIC FIELDS, ELECTRICAL ...
... Descriptors : *COMPRESSIBLE FLOW, VELOCITY, STAGNATION POINT, DISTRIBUTION, BOUNDARY LAYER, PERTURBATION THEORY ...
... Title : STAGNATION POINT HEAT TRANSFER MEASUREMENTS IN HYPERSONIC LOW REYNOLDS NUMBER FLOWS. ...
A solution of the Navier-Stokes equations is given for an incompressible stagnation point flow whose
... Accession Number : AD0269684. Title : ON THE VISCOUS FLOW NEAR THE STAGNATION POINT ON AN INTERFACE. ...
... Title : MEASUREMENTS OF HYPERVELOCITY STAGNATION POINT HEAT TRANSFER IN SIMULATED PLANETARY ATMOSPHERES. ...
... Accession Number : AD0297092. Title : GASEOUS RADIATION IN HYPERSONIC STAGNATION POINT FLOW. Corporate ...
Rarefied gas dynamics - measurements of stagnation heat transfer using calorimetric transient method
... CALCULATION OF STAGNATION POINT RADIATIVE HEAT TRANSFER (INCLUDING SHOCK LAYER RADIATIVE COOLING AND NONGRAY ...
The petrological consequences of deep subhorizontal deflection (�stagnation�) of subducting slabs should affect both apparent seismic velocity structures and slab morphology. We construct kinematic thermal models of stagnant slabs and perform thermodynamic modeling of the consequent perturbation of high-pressure phase transitions in mantle minerals, ...
The present paper deals with an experimental study of the stagnation-point heat transfer to a cooled copper surface with gas injection under subsonic conditions. Tests were made with a probe that combined a steady-state water-cooled calorimeter and that allows the capability to study convective blockage and to perform heat transfer measurements in presence ...
This paper is the first report on the characterization of the hydrodynamic conditions in a flow cell designed to study adsorption processes by spectroscopic ellipsometry. The resulting cell enables combining the advantages of in situ spectroscopic ellipsometry with stagnation point flow conditions. An additional advantage is that the proposed cell features a fixed position of ...
This paper is the first report on the characterization of the hydrodynamic conditions in a flow cell designed to study adsorption processes by spectroscopic ellipsometry. The resulting cell enables combining the advantages of in-situ spectroscopic ellipsometry with stagnation point flow conditions. An additional advantage is that the proposed cell features a fixed position of ...
The Plasma Liner Experiment (PLX) is attempting to form imploding plasma liners to reach 0.1 Mbar upon stagnation, via 30--60 spherically convergent plasma jets. PLX is partly motivated by the desire to develop a standoff driver for magneto-inertial fusion. The liner density, atomic makeup, and implosion velocity will help determine the maximum pressure that can be ...
As the nation has embraced the need to graduate every student ready for college and careers, high school reform has emerged at the top of the education agenda. Many local and state leaders are implementing strategies to address low performance and close achievement gaps. As federal policymakers look ahead to opportunities to support this work--including ...
The test procedures used to obtain the thermal performance data for a solar collector under simulated conditions are presented. Tests included a stagnation test, a time constant test, a thermal efficiency test, an incident angle modifier test, and a hot fill test. All tests were performed at ambient conditions and the transient effect ...
... Title : Undergraduate Academic Achievement as an Indicator of Fleet Performance and Retention. Descriptive Note : Master's thesis. ...
The inlet temperature of modern gas turbine engines has been increased to achieve higher thermal efficiency and increased output. The blade edge regions, including the blade tip, the leading edge, and the platform, are exposed to the most extreme heat loads, and therefore, must be adequately cooled to maintain safety. For the blade tip, there is tip leakage flow due to the ...
The wire-array z-pinch has in a very short time achieved remarkable performance as a powerful (>200 TW), pulsed soft x-ray source of high efficiency (~15%) and of great relevance to inertial confinement fusion. The underlying physics involves the transformation of wire cores to a plasma corona, the occurrence of uncorrelated axial instabilities, inward ...
Continuous high-speed water jets are presently used in many industrial applications such as cutting of various materials, cleaning and removal of surface layers. However, there is still a need for further research to enhance the performance of pure water jets. An obvious method is to generate water jets at ultra-high pressures (currently up to 700 MPa). An alternate approach ...
A monatomic, partly ionized gas with uniform stagnation properties is considered flowing in thermal equilibrium through a converging-diverging nozzle. The relationship is established between critical mass flow density and the following stagnation properties: pressure, enthalpy, and degree of ionization. Based on this relationship, thrust output ...
Pulsed, supersonic beams of pure carbon monoxide and carbon dioxide at stagnation conditions above their critical point have been investigated by time-of-flight measurements as a function of pressure and temperature. Although both molecules form clusters readily in adiabatic expansions, surprisingly large speed ratios (above 100) indicative of very low translational ...
A compressor model has been implemented in the RELAP5-3D© code. The model is similar to that of the existing pump model, and performs the same function on a gas as the pump performs on a single-phase or two-phase fluid. The compressor component consists of an inlet junction and a control volume, and optionally, an outlet junction. This feature permits ...
A compressor model has been implemented in the RELAP5-3D� code. The model is similar to that of the existing pump model, and performs the same function on a gas as the pump performs on a single-phase or two-phase fluid. The compressor component consists of an inlet junction and a control volume, and optionally, an outlet junction. This feature permits ...
the vicinity of a stagnation point with the main stream ... theory to anaTyze the flow at the stagnation point on a circular cylinder. ...
... description of the ion-electron flow in the stagnation-point boundary layer when negative potentials are applied at the stagnation point of the probe. ...
... 711. "4 ARL 83-25 4 011 0 SUPERSONIC STAGNATION POINT HEAT TRANSFER TO ... SUPERSONIC STAGNATION POINT HEAT TRANSFER TO ...
Determination of the stagnation-point location indicated that at angles of attack the stagnation point does not occur at the most forward point on the body , ...
DOC > NOAA > NESDIS > NCDC Search Field: Search NCDC Climate Monitoring Societal Impacts Air Stagnation Index Help Air Stagnation Index National Oceanic and Atmospheric...
Science.gov Websites
Photovoltaic systems generating electric power and thermal energy can operate at high efficiency if the thermal energy is generated at temperatures compatible with the operation of organic Rankine cycle engines. GaAs solar cells are well suited for such systems, since the cell can operate at relatively high functional temperatures without considerable performance degradation. ...
This paper describes the techniques developed for measuring stagnation-point radiation in NASA's cancelled Aeroassist Flight Experiment (AFE). It specifies the need for such a measurement; the types and requirements for the needed instruments; the Radiative Heating Experiment (RHE) developed for the AFE; the requirements, design parameters, and performance ...
Within the work on new collector designs for the Central European climate, investigations on two different collector systems using Transparent Insulation Materials (TIMs) are presented in this paper. The thermal and optical properties of a polycarbonate honeycomb material are discussed with respect to the design of improved flat-plate collectors and integrated storage collectors with TIMs. ...
The rapid air travel growth during the last three decades, has resulted in runway congestion at major airports. The current airports infrastructure will not be able to support the rapid growth trends expected in the next decade. Changes or upgrades in infrastructure alone would not be able to satisfy the growth requirements, and new airplane concepts such as the NASA proposed Super Short Takeoff ...
Simulating a supersonic wake flow field behind a conical body is a computing intensive task. It requires a large number of computational cells to capture the dominant flow physics and a robust numerical algorithm to obtain a reliable solution. High performance parallel computers with unique distributed processing and data storage capability can provide this need. They have ...
Combustion chamber deposit has adverse effects on the performance and operation of various combustion devices, such as boilers, furnaces and engines. To study deposits by actually running combustion device for a long time to gather the deposit is very time and money consuming. In this investigation, we developed a deposit-forming technique by using a spray burner with ...
One literature documents a significant, black-white gap in average test scores, while another finds a substantial narrowing of the gap during the 1980's, and stagnation in convergence after. We use two data sources -- the Long Term Trends NAEP and AFQT scores for the universe of applicants to the U.S. military between 1976 and 1991 -- to show: 1) the 1980's convergence is due ...
One literature documents a significant, black-white gap in average test scores, while another finds a substantial narrowing of the gap during the 1980's, and stagnation in convergence after. We use two data sources--the Long Term Trends NAEP and AFQT scores for the universe of applicants to the U.S. military between 1976 and 1991--to show: (1) the 1980's convergence is due to ...
Combined experimental and modeling studies of spatial effects (uniformity) in CF_4 -based plasma etching of silicon are presented. A modeling study of a multi-wafer radial flow reactor in which Si is etched by pure CF_4 is presented. The model includes detailed treatment of transport (including diffusion) and a simplified chemical kinetic network. Uniformity of etch rates across the reactor is ...
The increasing of stagnation pressure and Re number of gas flow is a very important for supersonic oxygen-iodine laser (COIL). This goal can be achieved with the aid of high pressure singlet oxygen generator (SOG) and high dilution of oxygen with buffer gas of high molecular weight downstream of SOG. The study of COIL operated with jet type SOG at 10 and ...
... Descriptors : (*LEARNING, PERFORMANCE(HUMAN)), (*SOCIAL PSYCHOLOGY, LEARNING), ACHIEVEMENT TESTS, VERBAL BEHAVIOR ...
