4,192 research outputs found
Flight evaluation of modifications to a digital electronic engine control system in an F-15 airplane
The third phase of a flight evaluation of a digital electronic engine control system in an F-15 has recently been completed. It was found that digital electronic engine control software logic changes and augmentor hardware improvements resulted in significant improvements in engine operation. For intermediate to maximum power throttle transients, an increase in altitude capability of up to 8000 ft was found, and for idle to maximum transients, an increase of up to 4000 ft was found. A nozzle instability noted in earlier flight testing was investigated on a test engine at NASA Lewis Research Center, a digital electronic engine control software logic change was developed and evaluated, and no instability occurred in the Phase 3 flight evaluation. The backup control airstart modification was evaluated, and gave an improvement of airstart capability by reducing the minimum airspeed for successful airstarts by 50 to 75 knots
Modified Paschos-Wolfenstein relation and extraction of weak mixing angle sin^2 theta_W
The NuTeV collaboration reported anomalously large weak mixing angle sin^2
theta_W in comparison with the standard model prediction. Neutrino and
antineutrino charged- and neutral-current events are analyzed for extracting
sin^2 theta_W. Although the Paschos-Wolfenstein relation is not directly used
in the analysis, it plays an important role in the determination. Noting that
the target nucleus, iron, is not an isoscalar nucleus, we derive a
leading-order expression for a modified Paschos-Wolfenstein relation for
nuclei, which may have neutron excess. Then, using charge and baryon-number
conservations for nuclei, we discuss a nuclear correction in the sin^2 theta_W
determination. It is noteworthy that nuclear modifications are different
between valence up- and down-quark distributions. We show this difference
effect on the NuTeV sin^2 theta_W deviation.Comment: 5 pages, REVTeX4.0, revtex4.cls, url.sty, natbib.sty, revsymb.sty,
10pt.rtx, aps.rtx, amssymb.sty, amsfonts.sty, 3 eps figures. Phys. Rev. D in
press. Email: [email protected] See also http://hs.phys.saga-u.ac.j
Global Music Perspectives: Music Outside the Western Canon in Local Schools
As a class, we are designing a research project for investigating how music teachers from counties in South-Central Pennsylvania use music from outside the Western canon (i.e. world music ). We are performing a qualitative study by interviewing k-12 music teachers from school districts in South-Central Pennsylvania. Teachers may choose to participate in a focus group interview with other teachers or in one-on-one interviews. The focus group interview will not exceed two hours and the one-on-one interviews will not exceed an hour. The interviews will be guided using a questionnaire (see attached), but the conversation may deviate from these questions at the discretion of the interviewer(s). We will transcribe these interviews to extract common thematic materials and relevant information. We will also compile a literature review of relevant peer-reviewed articles and use the data from said articles to expand upon our gathered information
Control technology for future aircraft propulsion systems
The need for a more sophisticated engine control system is discussed. The improvements in better thrust-to-weight ratios demand the manipulation of more control inputs. New technological solutions to the engine control problem are practiced. The digital electronic engine control (DEEC) system is a step in the evolution to digital electronic engine control. Technology issues are addressed to ensure a growth in confidence in sophisticated electronic controls for aircraft turbine engines. The need of a control system architecture which permits propulsion controls to be functionally integrated with other aircraft systems is established. Areas of technology studied include: (1) control design methodology; (2) improved modeling and simulation methods; and (3) implementation technologies. Objectives, results and future thrusts are summarized
Complex magnetism of B20-MnGe: from spin-spirals, hedgehogs to monopoles
B20 compounds are the playground for various non-trivial magnetic textures
such as skyrmions, which are topologically protected states. Recent
measurements on B20-MnGe indicate no clear consensus on its magnetic behavior,
which is characterized by the presence of either spin-spirals or 3-dimensional
objects interpreted to be a cubic lattice of hedgehogs and anti-hedgehogs.
Utilizing a massively parallel linear scaling all-electron density functional
algorithm, we find from full first-principles simulations on cells containing
thousands of atoms that upon increase of the compound volume, the state with
lowest energy switches across different magnetic phases: ferromagnetic,
spin-spiral, hedgehog and monopole
Electroweak radiative corrections to deep-inelastic neutrino scattering - implications for NuTeV ?
We calculate the O(alpha) electroweak corrections to charged- and
neutral-current deep-inelastic neutrino scattering off an isoscalar target. The
full one-loop-corrected cross sections, including hard photonic corrections,
are evaluated and compared to an earlier result which was used in the NuTeV
analysis. In particular, we compare results that differ in input-parameter
scheme, treatment of real photon radiation and factorization scheme. The
associated shifts in the theoretical prediction for the ratio of neutral- and
charged-current cross sections can be larger than the experimental accuracy of
the NuTeV result.Comment: 19 pages late
Accurate evaluation of the interstitial KKR-Green function
It is shown that the Brillouin zone integral for the interstitial KKR-Green
function can be evaluated accurately by taking proper care of the free-electron
singularities in the integrand. The proposed method combines two recently
developed methods, a supermatrix method and a subtraction method. This
combination appears to provide a major improvement compared with an earlier
proposal based on the subtraction method only. By this the barrier preventing
the study of important interstitial-like defects, such as an electromigrating
atom halfway along its jump path, can be considered as being razed.Comment: 23 pages, RevTe
Human Asset Accounting And Measurement: Moving Forward
Changes in the accounting profession and in the way organizations are managed and operated over the past several decades have led to the identification of a new factor that makes up a substantial part of the value of an organization: human capital. The value that employees add to organizations, however, has been difficult to measure because of the many elements that comprise it and aspects of human nature and free will that are involved. Many models have been proposed to capture the value that organizations gain from employees, but none have succeeded in full. Additionally, strict financial reporting regulations would require an accurate and uniform method of accounting for human capital in order to give much relevance to the data collected. Despite its complex nature, the field of human asset accounting continues to gain momentum and is headed in the right direction. The development of a universal method of accounting for human capital would provide a much more exact valuation of organizations and have deep benefits for owners, managers, investors, accountants, and human resource employees. This paper examines the history of human asset accounting and its feasibility in current financial reporting environments. Additionally, it demonstrates the importance of human asset accounting, different approaches toward human asset accounting, and how beneficial an accurate method could prove to be in financial reporting. Finally, the paper recommends that, as a precursor to measurement, the development of general quantitative and qualitative human capital disclosures, with real company examples, be included in a company’s sustainability reporting
- …