A military perspective on small unmanned aerial vehicles

In recent years, advancements in three technology areas, microelectronics, MEMS sensors, and GPS receivers, have allowed small UAVs to overcome critical deficiencies and become practical for insertion into the military mainstream. The maturation and commercialization of these technologies have resulted in readily available components that have decreased in both size and cost, to the point where truly low-cost, highly capable, small UAVs are possible. In particular, inertial devices such as MEMS accelerometers and angular rate sensors, pressure sensors, and magnetometers have reached the point where they are reliable, accurate, and affordable. These devices allow the determination of vehicle state with the precision required to enable autonomous flight. In addition, advanced microelectronic devices, such as digital signal processors, field programmable gate arrays, and microcontrollers have enabled sophisticated flight control functions, including fully autonomous flight using GPS waypoints. In combination, these advances have allowed small UAVs such as Pointer, Raven, and Dragon Eye to move into full-scale production and continue to allow the progression of UAVs into smaller and smaller packages. To address several of the deployment issues connected with small UAVs, a gun-launched version, along with the underpinning technologies, is under development. This device represents a clear departure from conventional UAVs with several clear advantages; however, it also contains severe design challenges, as well as test and evaluation dilemmas. An option of this type is envisioned not as a replacement for conventional small UAVs but rather as an augmenting capability.     

PdO/Pd system equilibrium phase diagram under a gas mixture of oxygen and nitrogen

The thermal equilibrium decomposition properties of the PdO-Pd system under oxygen partial pressures ranging from 0.1 to 1.0 atm in a total combined pressure of oxygen and nitrogen of 1.0 atm were investigated by means of thermal-gravimetric analyses. The phase diagram of Pd-PdO over the range of oxygen/nitrogen gas concentration was established. The decomposition temperature of PdO to Pd was found to increase with the partial pressure of oxygen.     

MULTIMEDIA NETWORKING A Leading-Edge Communication Technology

The realization of digital multimedia's full business potential requires networking. This article discusses the value-added benefits to the corporation of networked multimedia as well as the choice of architectures and technologies needed to deliver multimedia networking solutions.     

Use of weibull statistics to quantify property variability in TiAl alloys

Tensile experiments have been performed on specimens of four different investment-cast TiAl-based alloys with variations in casting conditions. The average ductilities obtained in these experiments vary between approximately 0.8 to 2.0 pct plastic strain to failure in tension. By using the three-parameter form of the Weibull relation, with the 0.2 pct offset yield strength as the minimum failure strength, the resulting variability in the data can be quantified and is found to be similar for those alloys with similar microstructural scale (grain size). Large variations in lamellar volume fraction, segregation, and phase distribution have a minor influence on property variability, compared to changes in the scale of the grain structure caused by either variations in cooling rate during casting or the addition of grain refiners.     

裂缝性油气藏采收率：100个裂缝性油气田实例的经验总结

通过对世界上100个裂缝性油气藏的综合评价，研究储集层及流体本身的性质(包括孔隙度、渗透率、黏度、可动油比例、含水饱和度、润湿性及裂缝分布特征等)和驱动机制及油藏管理战略(优化日产量和采用不同类型的提高采收率技术)对其最终采收率的影响。将裂缝性油气藏分为4类：I类的基质几乎没有孔隙度和渗透率，裂缝是储存空间和流体流动的通道；Ⅱ类的基质有较低的孔隙度和渗透率，基质提供储存空间，裂缝提供流动通道；Ⅲ类(微孔隙)的基质具有高孔隙度和低渗透率，基质提供储存空间，裂缝提供流动通道；Ⅳ类(大孔隙)的基质具有高的孔隙度和渗透率，基质提供储存空间和流动通道，裂缝仅增加渗透率。对26个Ⅱ类油气藏和20个Ⅲ类油气藏的开采历史的研究表明：Ⅱ类油气藏的采收率受水驱强度和最优日产量控制，日产量过高会很容易破坏Ⅱ类油气藏，一些Ⅱ类油气藏如果管理得当，采收率可以很高，不需要二次或三次采油；Ⅲ类油气藏的采收率主要受岩石和流体本身性质的影响，特别是基质渗透率、流体重度、润湿性以及裂缝强度等，不进行二次或三次采油不可能完全开采，往往需要采用一些提高采收率的专门技术。以往将Ⅱ类和Ⅲ类裂缝性油气藏归为一类，认识它们的区别将有助于选择更好的开发策略。     

Exceptions that prove the rule--Using a theory of motivated social cognition to account for ideological incongruities and political anomalies: Reply to Greenberg and Jonas (2003).

A meta-analysis by J. T. Jost, J. Glaser, A. W. Kruglanski, and F. J. Sulloway (2003) concluded that political conservatism is partially motivated by the management of uncertainty and threat. In this reply to J. Greenberg and E. Jonas (2003), conceptual issues are clarified, numerous political anomalies are explained, and alleged counterexamples are incorporated with a dynamic model that takes into account differences between "young" and "old" movements. Studies directly pitting the rigidity-of-the-right hypothesis against the ideological extremity hypothesis demonstrate strong support for the former. Medium to large effect sizes describe relations between political conservatism and dogmatism and intolerance of ambiguity; lack of openness to experience; uncertainty avoidance; personal needs for order, structure, and closure; fear of death; and system threat. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

History of Construction, Engineering, and Management in the Department of Civil and Environmental Engineering at Penn State

At Penn State, the credit for broadening the Civil Engineering Department’s longstanding academic focus on analysis and design to include the construction phase must go to Dr. Harmer A. Weeden and his longtime associate Dr. Thomas D. Larson. Jack H. Willenbrock joined the Department as an Instructor in June 1968 and grew the construction program so that today about a fourth to a third of the civil undergraduates obtain employment in the construction industry. The program has awarded about 250 postbaccalaureate degrees.