8,596 research outputs found
Thermoelectric temperature control system for the pushbroom microwave radiometer (PBMR)
A closed loop thermoelectric temperature control system is developed for stabilizing sensitive RF integrated circuits within a microwave radiometer to an accuracy of + or - 0.1 C over a range of ambient conditions from -20 C to +45 C. The dual mode (heating and cooling) control concept utilizes partial thermal isolation of the RF units from an instrument deck which is thermally controlled by thermoelectric coolers and thin film heaters. The temperature control concept is simulated with a thermal analyzer program (MITAS) which consists of 37 nodes and 61 conductors. A full scale thermal mockup is tested in the laboratory at temperatures of 0 C, 21 C, and 45 C to confirm the validity of the control concept. A flight radiometer and temperature control system is successfully flight tested on the NASA Skyvan aircraft
Finite Element Modeling of Microstructural Changes in Turning of AA7075-T651 Alloy and Validation
The surface characteristics of a machined product strongly influence its functional performance. During machining, the grain size of the surface is frequently modified, thus the properties of the machined surface are different to that of the original bulk material. These changes must be taken into account when modeling the surface integrity effects resulting from machining. In the present work, grain size changes induced during turning of AA 7075-T651 (160 HV) alloy are modeled using the Finite Element (FE) method and a user subroutine is implemented in the FE code to describe the microstructural change and to simulate the dynamic recrystallization, with the consequent formation of new grains. In particular, a procedure utilizing the Zener-Hollomon and Hall-Petch equations is implemented in the user subroutine to predict the evolution of the material grain size and the surface hardness when varying the cutting speeds (180 - 720 m/min) and tool nose radii (0.4 - 1.2 mm). All simulations were performed for dry cutting conditions using uncoated carbide tools. The effectiveness of the proposed FE model was demonstrated through its capability to predict grain size evolution and hardness modification from the bulk material to machined surface. The model is validated by comparing the predicted results with those experimentally observed
The baryon octet magnetic moments to all orders in flavor breaking; an application to the problem of the strangeness in the nucleon
Using the general QCD parametrization (GP) we display the magnetic moments of
the octet baryons including all flavor breaking terms to any order. The
hierarchy of the GP parameters allows to estimate a parameter related
to the quark loops contribution of the proton magnetic moment; its order of
magnitude is predicted to be inside a comparatively small interval including
the value given recently by Leinweber et al. by a lattice QCD calculationComment: (13 pages- version accepted for publication Phys.Rev.D. Note added in
last section, 2 references adde
THE INVOLVEMENT OF NEBRASKA VOCATIONAL EDUCATION SECONDARY SCHOOL ADVISORY COUNCILS IN THE PREPARATION OF THE LOCAL PLAN FOR VOCATIONAL EDUCATION
With passage of the 1976 Vocational Education Amendments, PL 94-482, local schools were required to establish an advisory council or councils to enable lay persons to have input into decisions regarding the local secondary vocational education program. This policy was established on the rationale that local citizens have a right and responsibility to assist in the decisions concerning which clientele groups will be served by the local school, and what knowledges these persons should receive.
The State Advisory Council for Vocational Education, in an effort to fulfill one of its responsibilities, asked that a statewide status study be conducted to evaluate Nebraska’s progress in the implementation of this aspect of the law. The resulting data will enable the State Advisory Council to provide accountability to the federal level, and serve as a baseline study for later research on the role of local vocational education advisory councils in Nebraska
Buy High Sell Low: Redefining Bean Counting in the Coffee Industry for a Sustainable Future
Charles Manz returns to the JVBL providing ‒ together with several fellow researchers/writers ‒ a case study of a socially responsible business within the coffee industry. Familiar CSR concepts are examined such as Fair Trade and sustainability which foster parity in dealing with buyers while maintaining product quality and reasonable income. The practices of Dean’s Beans, a progressive coffee organization, are examined as a notable demonstration of how a business can fiscally succeed while maintaining a commitment to the triple-bottom-line considerations of people, planet, and profits
Monte Carlo Simulation of Ising Models with Dipole Interaction
Recently, a new memory effect was found in the metamagnetic domain structure
of the diluted Ising antiferromagnet by domain imaging
with Faraday contrast. Essential for this effect is the dipole interaction. We
simulate the low temperature behavior of diluted Ising-antiferromagnets by a
Monte Carlo simulation considering long range interaction. The metamagnetic
domain structure occurring due to the dipole interaction is investigated by
graphical representation. In the model considered the antiferromagnetic state
is stable for an external magnetic field smaller than a lower boundary
while for fields larger than an upper boundary the system is in the
saturated paramagnetic phase, where the spins are ferromagnetically polarized.
For magnetic fields in between these two boundaries a mixed phase occurs
consisting of ferromagnetic domains in an antiferromagnetic background. The
position of these ferromagnetic domains is stored in the system: after a cycle
in which the field is first removed and afterwards applied again the domains
reappear at their original positions. The reason for this effect can be found
in the frozen antiferromagnetic domain state which occurs after removing the
field.Comment: Latex, 10 pages; 3 postsript-figures, compressed tar-file, uuencoded,
report 10109
POTENTIAL EFFECTS OF SUBSIDIZED LIVESTOCK INSURANCE ON LIVESTOCK PRODUCTION
Recent legislation has cleared the way for subsidized livestock price insurance. Such programs could increase production. Expected feeder cattle prices with and without subsidized insurance will be analyzed using E-V and Stochastic Dominance. Results will highlight the potential effects of the program on marketing risk and production decisions.Livestock Production/Industries, Risk and Uncertainty,
Notes on a collection of birds from Mindoro Island, Philippines
The 1954 Yale Peabody Museum-Silliman University Mindoro Zoological Expedition, headed by D. S. Rabor, stayed in the field from March 21 until June 7, 1954….https://elischolar.library.yale.edu/peabody_museum_natural_history_bulletin/1012/thumbnail.jp
AN ASSESSMENT OF APPLIED BIOLOGICAL SCIENCE INTERESTS OF SEVENTH GRADE STUDENTS!
Vocational education programs in high schools should be designed to prepare young people for their next pursuit after graduation. Students\u27 interests, needs, and employment opportunities should form the basis upon which decisions are made concerning what vocational courses to offer in the high school curriculum
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