Improved method of fabricating planar gallium arsenide diodes

Improved method fabricates electroluminescent planar P-N gallium arsenide diodes. GaAs is masked with silicon monoxide to allow P-type impurities to be diffused into unmasked portions of GaAs to form P-N junctions

Unspeakable Suffering; Eloquent Explanations: National Civil War Medicine Museum’s 26th Annual Conference

On Friday, October 12th, 2018, the National Civil War Medicine Museum kicked off its 26th annual conference and began its three-day event with a series of lectures on topics ranging from Confederate medical practice to cultural understandings of cowardice. A series of unique lectures given by a professionally diverse cast of presenters illuminated the often-peripheral field of Civil War Medicine. [excerpt

Making Photographs Speak

It has often been said that “a picture is worth a thousand words.” Making that picture spit out those mythical thousand words, as we can all attest, is no easy task. Over the course of the first half of the fall semester, the three of us were tasked with developing brief interpretive captions for two Civil War photographs each, with the end goal to display our work at the Civil War Institute’s 2019 Summer Conference. What initially appeared as a simple project quickly revealed itself to be a difficult, yet rewarding, challenge that taught us all important lessons concerning history, photography, and writing that we will not soon forget. Producing the photography exhibit enhanced our skills as historical writers, introduced us to the challenge of writing for a popular audience, and deepened our understanding of Civil War photography. [excerpt

Agency Risks in Outsourcing Corporate Real Estate Functions

Firms outsource business functions to focus on core competencies and cut operating expenses. However, companies must consider agency costs in determining the optimal staffing/outsourcing balance. Analysis of the views of corporate real estate managers and real estate service providers indicate that although they share a common vision of the role of corporate real estate, providers focus more on traditional real estate tasks than on corporate business strategy. The optimum balance of staffing/outsourcing may consist of a corporate real estate staff that understands the overall corporate strategy and devotes its resources to strategic planning, program development, contracting, and monitoring outsourced tasks.

Time, Place, Space, Technology and Corporate Real Estate Strategy

Few corporations take a strategic approach to managing real estate. This survey finds that corporate real estate managers and service providers in Australia, Hong Kong, the United Kingdom and the United States continue to fulfill a traditional transactional role within their organizations. Real estate is not cooperating with other parts of the organization to provide their companies with flexibility that could increase competitiveness. While the use of technology is growing, real estate managers remain uncertain about its role in their future. Corporate real estate managers believe that to be effective in the future they will need strategic planning skills and business knowledge.

Supersymmetry versus black holes at the LHC

Supersymmetry and extra dimensions are the two most promising candidates for new physics at the TeV scale. Supersymmetric particles or extra-dimensional effects could soon be observed at the Large Hadron Collider. We propose a simple but powerful method to discriminate the two models: the analysis of isolated leptons with high transverse momentum. Black hole events are simulated with the CATFISH black hole generator. Supersymmetry simulations use a combination of PYTHIA and ISAJET, the latter providing the mass spectrum. Our results show the measure of the dilepton invariant mass provides a strong signature to differentiate supersymmetry and black hole events at the Large Hadron Collider. Analysis of event-shape variables and multilepton events complement and strengthen this conclusion.Comment: 12 pages, 5 figure

Microelectromechanical systems vibration powered electromagnetic generator for wireless sensor applications

This paper presents a silicon microgenerator, fabricated using standard silicon micromachining techniques, which converts external ambient vibrations into electrical energy. Power is generated by an electromagnetic transduction mechanism with static magnets positioned on either side of a moving coil, which is located on a silicon structure designed to resonate laterally in the plane of the chip. The volume of this device is approximately 100 mm3. ANSYS finite element analysis (FEA) has been used to determine the optimum geometry for the microgenerator. Electromagnetic FEA simulations using Ansoft’s Maxwell 3D software have been performed to determine the voltage generated from a single beam generator design. The predicted voltage levels of 0.7–4.15 V can be generated for a two-pole arrangement by tuning the damping factor to achieve maximum displacement for a given input excitation. Experimental results from the microgenerator demonstrate a maximum power output of 104 nW for 0.4g (g=9.81 m s1) input acceleration at 1.615 kHz. Other frequencies can be achieved by employing different geometries or material

Revisiting the double-binary-pulsar probe of non-dynamical Chern-Simons gravity

One of the popular modifications to the theory of general relativity is non-dynamical Chern-Simons (CS) gravity, in which the metric is coupled to an externally prescribed scalar field. Setting accurate constraints to the parameters of the theory is important owing to their implications for the scalar field and/or the underlying fundamental theory. The current best constraints rely on measurements of the periastron precession rate in the double-binary-pulsar system and place a very tight bound on the characteristic CS lengthscale k_cs^{-1} <~ 3*10^{-9} km. This paper considers several effects that were not accounted for when deriving this bound and lead to a substantial suppression of the predicted rate of periastron precession. It is shown, in particular, that the point mass approximation for extended test bodies does not apply in this case. The constraint to the characteristic CS lengthscale is revised to k_cs^{-1} <~ 0.4 km, eight orders of magnitude weaker than what was previously found.Comment: 12 pages, 4 figures, to be submitted to PRD. Comments are welcom