8,260 research outputs found

    Installation drag considerations as related to turboprop and turbofan engines

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    Some of the specific areas associated with straight jet and turboprop engine installations are outlined where drag reduction and, thus, improved aircraft system performance is obtained. Specific areas constitute air intake sizing for general aviation aircraft, exhaust duct geometries and cooling system arrangements for propeller powered aircraft

    Two-way digital driver/receiver uses one set of lines

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    Two-way /bilateral/ digital driver/receiver system using MOS circuits was designed for a multiprocess computer having several subsystems at relatively close locations. The system requires only a single set of communication lines between subsystems, thus achieving lower cost with increased reliability

    BCS Theory for Trapped Ultracold Fermions

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    We develop an extension of the well-known BCS-theory to systems with trapped fermions. The theory fully includes the quantized energy levels in the trap. The key ingredient is to model the attractive interaction between two atoms by a pseudo-potential which leads to a well defined scattering problem and consequently a BCS-theory free of divergences. We present numerical results for the BCS critical temperature and the temperature dependence of the gap. They are used as a test of existing semi-classical approximations.Comment: 4 pages, 3 figures, submitted to PR

    Sesame-Style Decomposition of KS-DFT Molecular Dynamics for Direct Interrogation of Nuclear Models

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    A common paradigm used in the construction of equations of state is to decompose the thermodynamics into a superposition of three terms: a static-lattice cold curve, a contribution from the thermal motion of the nuclei, and a contribution from the thermal excitation of the electrons. While statistical mechanical models for crystals provide tractable framework for the nuclear contribution in the solid phase, much less is understood about the nuclear contribution above the melt temperature (Cv(nuc)3RC_v^{(\text{nuc})}\approx 3R) and how it should transition to the high-temperature limit (Cv(nuc)32RC_v^{(\text{nuc})} \sim \frac{3}{2}R). In this work, we describe an algorithm for extracting both the thermal nuclear and thermal electronic contributions from quantum molecular dynamics (QMD). We then use the VASP QMD package to probe thermal nuclear behavior of liquid aluminum at normal density to compare the results to semi-empirical models -- the Johnson generic model, the Chisolm high-temperature liquid model, and the CRIS model.Comment: 6 pages, 4 figures, APS Shock Compression of Condensed Matter Conference Proceedings 201

    Study of small turbofan engines applicable to general-aviation aircraft

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    The applicability of small turbofan engines to general aviation aircraft is discussed. The engine and engine/airplane performance, weight, size, and cost interrelationships are examined. The effects of specific engine noise constraints are evaluated. The factors inhibiting the use of turbofan engines in general aviation aircraft are identified

    Characterisation of the dynamical quantum state of a zero temperature Bose-Einstein condensate

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    We describe the quantum state of a Bose-Einstein condensate at zero temperature. By evaluating the Q-function we show that the ground state of Bose-Einstein condensate under the Hartree approximation is squeezed. We find that multimode Schroedinger cat states are generated as the condensate evolves in a ballistic expansion.Comment: 13 pages, 6 figure

    The Evolution of Women Pastors in Mainline Protestant Denominations

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    Subsequent to receiving official approval from denominational authorities more than 40 years ago, an increasing number of women appear to be expressing a ministerial call upon their lives and entering pastoral leadership. Many women pastors find acceptance in mainline protestant denominations (MPD). Yet, despite improvements, women still face unique challenges in ministry compared with men. Nevertheless, they continue to pursue opportunities in ministry. Mentoring helps offset impediments and provides a professional development outlet for enhancing skill sets and empowering women to overcome these hurdles. Thus, the purpose behind this study remains to identify challenges faced by women pastors related to acceptance in MPD and to examine the mentoring models used, if any, for their professional development. Seven mainline denominations served as focal points for this endeavor: United Methodist Church, Evangelical Lutheran Church in America, Presbyterian Church, the Episcopal Church, American Baptist Church, United Church of Christ, and Christian Church Disciples of Christ. A qualitative, case study design provides the framework for this study. One female pastor from each of the seven denominations was purposely selected to participate in a semi-structured interview. Additionally, eight “wild card” options were intentionally chosen for contribution: two male leaders, two professors, two lay members, and two additional female pastors. Two research questions divided into 10 interview questions, as well as a demographic questionnaire encompassed the data gathering materials for this examination. Summarized lists of challenges experienced and mentoring models used captured four main themes relating to journey, challenges, acceptance, and mentoring. Almost all findings for this study are supported by empirically-based literature. Conclusively, many women in pastoral professions experience challenges and limitations from peers, congregants, and the public when accepting and pursuing a call to ministry. Despite the seemingly overwhelming data that suggest women in ministry face an excessive amount of challenges, some remain who not only support the concept, but also embrace it. This leads to empowerment for women that provides satisfying and fulfilling work which produces motivation and retention, not to mention spiritual and worthwhile benefits

    Development during adolescence of the neural processing of social emotion

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    In this fMRI study, we investigated the development between adolescence and adulthood of the neural processing of social emotions. Unlike basic emotions (such as disgust and fear), social emotions (such as guilt and embarrassment) require the representation of another's mental states. Nineteen adolescents (10–18 years) and 10 adults (22–32 years) were scanned while thinking about scenarios featuring either social or basic emotions. In both age groups, the anterior rostral medial prefrontal cortex (MPFC) was activated during social versus basic emotion. However, adolescents activated a lateral part of the MPFC for social versus basic emotions, whereas adults did not. Relative to adolescents, adults showed higher activity in the left temporal pole for social versus basic emotions. These results show that, although the MPFC is activated during social emotion in both adults and adolescents, adolescents recruit anterior (MPFC) regions more than do adults, and adults recruit posterior (temporal) regions more than do adolescents
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