9,689 research outputs found
Demand Potential for Goat Meat in Southern States: Empirical Evidence from a Multi-State Goat Meat Consumer Survey
A survey conducted in 11 Southeastern states elicits consumers' demand and preferences for various goat meat products. The data permit examination of goat meat demand of ethnic populations and the diversity among the states surveyed. The study uses five econometric models to examine the current demand, potential demand, and demand related to season and occasions on the goat meat market. Our analysis suggests that there exist a substantial demand for goat meat and the potential increase in the demand. The findings also identify the major factors in the determination of goat meat purchasing behavior.Demand, Logit Model, Goat Meat, Demand and Price Analysis,
Wind-tunnel investigation of the validity of a sonic-boom-minimization concept
The Langley unitary plan unitary plan wind tunnel was used to determine the validity of a sonic-boom-minimization theory. Five models - two reference and three low-boom constrained - were tested at design Mach numbers of 1.5 and 2.7. Results show that the pressure signatures generated by the low-boom models had significantly lower overpressure levels than those produced by the reference models and that small changes in the Mach number and/or the lift caused relatively small changes in the signature shape and overpressure level. Boundary-layer effects were found in the signature shape and overpressure level. Boundary-layer effects were found to be sizable on the low-boom models, and when viscous corrections were included in the analysis, improved agreement between the predicted and the measured signatures was noted. Since this agreement was better at Mach 1.5 than at Mach 2.7, it was concluded that the minimization method was definitely valid at Mach 1.5 and was probably valid at Mach 2.7, with further work needed to resolve the uncertainty
Numerical Investigation of Second Mode Attenuation over Carbon/Carbon Surfaces on a Sharp Slender Cone
We have carried out axisymmetric numerical simulations of a spatially
developing hypersonic boundary layer over a sharp 7-half-angle cone
at inspired by the experimental investigations by Wagner (2015).
Simulations are first performed with impermeable (or solid) walls with a
one-time broadband pulse excitation applied upstream to determine the most
convectively-amplified frequencies resulting in the range 260kHz -- 400kHz,
consistent with experimental observations of second-mode instability waves.
Subsequently, we introduce harmonic disturbances via continuous periodic
suction and blowing at 270kHz and 350kHz. For each of these forcing frequencies
complex impedance boundary conditions (IBC), modeling the acoustic response of
two different carbon/carbon (C/C) ultrasonically absorptive porous surfaces,
are applied at the wall. The IBCs are derived as an output of a pore-scale
aeroacoustic analysis -- the inverse Helmholtz Solver (iHS) -- which is able to
return the broadband real and imaginary components of the surface-averaged
impedance. The introduction of the IBCs in all cases leads to a significant
attenuation of the harmonically-forced second-mode wave. In particular, we
observe a higher attenuation rate of the introduced waves with frequency of
350kHz in comparison with 270kHz, and, along with the iHS impedance results, we
establish that the C/C surfaces absorb acoustic energy more effectively at
higher frequencies.Comment: AIAA-SciTech 201
Current research in sonic-boom minimization
A review is given of several questions as yet unanswered in the area of sonic-boom research. Efforts, both here at Langley and elsewhere, in the area of minimization, human response, design techniques and in developing higher order propagation methods are discussed. In addition, a wind-tunnel test program being conducted to assess the validity of minimization methods based on a forward spike in the F-function is described
A Pilot Study of Halal Goat-Meat Consumption in Atlanta, Georgia
Atlanta is a relatively large market for goat meat. As in most metropolitan areas around the U.S., goat-meat consumption has grown steadily in Atlanta over the past decade (Northwest Cooperative Development Center 2005; Nettles and Bukenya 2004). This growth is attributed to the influx of immigrants from goat-meat-eating countries into the U.S. over the same period (Gipson 1999). The increase in demand for goat meat has made the U.S. a net importer of competitively priced goat meat from Australia and New Zealand into major U.S cities such as Atlanta (USDA-FAS 2006). The fact that goat-meat imports from Australia have steadily increased over the years makes markets such as Atlanta of particular interest to both Georgia goat-meat suppliers and meat-goat producers. The goat-meat market, however, is highly segmented (Nelson et al. 2004; Mclean-Meyinsse 2003). Recognition of the diversity among Atlanta goat-meat consumers raises interest in identifying preferences of particular segments. One such segment is the Muslim consumer. However, very limited information is available to help assess the preferences of Muslim consumers in the Atlanta goat-meat market. This study focuses on the Muslim segment of actual goat-meat consumers in the metro Atlanta area. Contrary to earlier assertions, we hypothesize that Muslims eat goat-meat for cultural reasons and not for religious reasons. Furthermore, we assert that Muslims are not a single homogenous niche group and should not be treated as such in marketing. Thus this study examines goat-meat consumption patterns among Muslims in metropolitan Atlanta. Insights gained in this study benefit meat-goat producers and consumers in Georgia.Food Consumption/Nutrition/Food Safety, Livestock Production/Industries,
Absolute and convective instabilities of an inviscid compressible mixing layer: Theory and applications
This study aims to examine the effect of compressibility on unbounded and parallel shear flow linear instabilities. This analysis is of interest for industrial, geophysical, and astrophysical flows. We focus on the stability of a wavepacket as opposed to previous single-mode stability studies. We consider the notions of absolute and convective instabilities first used to describe plasma instabilities. The compressible-flow modal theory predicts instability whatever the Mach number. Spatial and temporal growth rates and Reynolds stresses nevertheless become strongly reduced at high Mach numbers. The evolution of disturbances is driven by Kelvin -Helmholtz instability that weakens in supersonic flows. We wish to examine the occurrence of absolute instability, necessary for the appearance of turbulent motions in an inviscid and compressible two-dimensional mixing layer at an arbitrary Mach number subject to a three-dimensional disturbance. The mixing layer is defined by a parametric family of mean-velocity and temperature profiles. The eigenvalue problem is solved with the help of a spectral method. We ascertain the effects of the distribution of temperature and velocity in the mixing layer on the transition between convective and absolute instabilities. It appears that, in most cases, absolute instability is always possible at high Mach numbers provided that the ratio of slow-stream temperature over fast-stream temperature may be less than a critical maximal value but the temporal growth rate present in the absolutely unstable zone remains small and tends to zero at high Mach numbers. The transition toward a supersonic turbulent regime is therefore unlikely to be possible in the linear theory. Absolute instability can be also present among low-Mach-number coflowing mixing layers provided that this same temperature ratio may be small, but nevertheless, higher than a critical minimal value. Temperature distribution within the mixing layer also has an effect on the growth rate, this diminishes when the slow stream is heated. These results are applied to the dynamics of mixing layers in the interstellar medium and to the dynamics of the heliopause, frontier between the interstellar medium, and the solar wind. (C) 2009 American Institute of Physics
Design evaluation criteria for commercial STOL transports
Handling qualities criteria and operational performance margins have been determined for the landing phase of commercial short-takeoff-and-landing airplanes. The requirements are the result of a literature survey, analysis of areas found to be inadequately covered by current criteria, and a subsequent piloted simulator investigation of critical criteria requiring substantiation. Three complete simulator models were used, each describing the characteristics of a different high-lift system, the externally blown flap, the augmentor flap, and the internally blown flap. The proposed criteria are presented with substantiating discussions from currently available data or directly from the results of this simulation work where it is applicable
Polymer Dissolution Model: An Energy Adaptation Of The Critical Ionization Theory
The current scale of features size in the microelectronics industry has reached the point where molecular level interactions affect process fidelity and produce excursions from the continuum world like line edge roughness (LER). Here we present a 3D molecular level model based on the adaptation of the critical ionization (CI) theory using a fundamental interaction energy approach. The model asserts that it is the favorable interaction between the ionized part of the polymer and the developer solution which renders the polymer soluble. Dynamic Monte Carlo methods were used in the current model to study the polymer dissolution phenomenon. The surface ionization was captured by employing an electric double layer at the interface, and polymer motion was simulated using the Metropolis algorithm. The approximated interaction parameters, for different species in the system, were obtained experimentally and used to calibrate the simulated dissolution rate response to polymer molecular weight and developer concentration. The predicted response is in good agreement with experimental dissolution rate data. The simulation results support the premise of the CI theory and provide an insight into the CI model from a new prospective. This model may provide a means to study the contribution of development to LER and other related defects based on molecular level interactions between distinct components in the polymer and the developer.Chemical Engineerin
Polemic in the International Court of Justice
Jurisprudence, used as a technical term, has two meanings of equal currency, referring both to a philosophy of law and a science which treats of the principles of positive law and legal relations. These meanings are vastly different in import. Philosophy suggests speculation and ideology, while science suggests fact and functionalism. Jurisprudence, like any discipline of observation and conclusion, can be a very useful tool in the legal analysis of one\u27s own work and the work of others. The science, with its clear sight and objective standards, is obviously more dependable than the polemics of philosophy, and therefore the sole approach to be used in situations that demand objectivity. If any area of jurisprudence demands this objectivity, it is the area of judicial decision. It is the premise of this Comment that much of what is written about legal judgments, and often the judgments themselves, contain so much polemic that they sometimes produce results contrary to a primary function of legal systems, the settlement of disputes. This is an especially critical problem in the international sphere, where the tendency to mix fact and polemic often detracts from the legal justifications of a particular dispute\u27s resolution
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