Unmanned Aerial Vehicle Flight Test Approval Process and its Implications: A Methodological Approach to Capture and Evaluate Hidden Costs and Value in the Overall Process

The advancement in small unmanned aerial vehicle (SUAV) technology has brought a new revolution in the military domain. Their uses have become more synonymous with intelligence, surveillance, and reconnaissance missions. Concerns over their flight test safety and accountability have been addressed in multiple policies to mitigate mishaps and increase proper accountability. However, current DoD and FAA mandated regulations and policies concerning UAV flight tests are sometimes considered slow and time-consuming, which may lead to delays in UAV research and development. This study explores the quantitative and qualitative measure of benefits associated with an abbreviated flight test process for SUAVs. Specifically, it examines the current agreement between two major USAF research centers regarding the SUAV flight test approval process. This research utilized high-level multidisciplinary approaches and techniques including qualitative cost benefit analysis, interviews, value stream mapping (VSM) analysis, and heuristic risk analysis to evaluate the current-state process. The findings conclude that there is a slight economic cost and schedule savings in an abbreviated process. Additionally, this research finds no correlation between SUAV flight mishaps and system maturity. This research proposes using a streamlined process for additional safety reviews to eliminate non-value added process steps considered unnecessary due to the nature of the SUAV complexity. Furthermore, this study recommends using a decision rule matrix based on the total cost of the SUAV and its weight and energy at impact for choosing an abbreviated flight test safety review process

Doping change and distortion effect on double-exchange ferromagnetism

Doping change and distortion effect on the double-exchange ferromagnetism are studied within a simplified double-exchange model. The presence of distortion is modelled by introducing the Falicov-Kimball interaction between itinerant electrons and classical variables. By employing the dynamical mean-field theory the charge and spin susceptibility are exactly calculated. It is found that there is a competition between the double-exchange induced ferromagnetism and disorder-order transition. At low temperature various long-range order phases such as charge ordered and segregated phases coexist with ferromagnetism depending on doping and distortion. A rich phase diagram is obtained.Comment: 8 pages, 8 figure

Goos-Haenchen induced vector eigenmodes in a dome cavity

We demonstrate numerically calculated electromagnetic eigenmodes of a 3D dome cavity resonator that owe their shape and character entirely to the Goos-Haenchen effect. The V-shaped modes, which have purely TE or TM polarization, are well described by a 2D billiard map with the Goos-Haenchen shift included. A phase space plot of this augmented billiard map reveals a saddle-node bifurcation; the stable periodic orbit that is created in the bifurcation corresponds to the numerically calculated eigenmode, dictating the angle of its "V". A transition from a fundamental Gaussian to a TM V mode has been observed as the cavity is lengthened to become nearly hemispherical.Comment: 4 pages, 4 figure

Behavior and the Response of Cancer Cells on Anticancer Drug Treatment Monitored with Microelectrode Array

AbstractA cell-based impedance biosensor using microelectrode array has been developed for monitoring cellular activities of MCF-7 breast cancer cells and evaluating drug-induced apoptosis. Using this device, different activities of cells such as cell attachment, adhesion, and spreading are monitored by measuring impedance spectra and interpreting the data using an electrical equivalent circuit. In order to demonstrate pharmaceutical relevance, the cells were treated with 25μM of anti-cancer drug Cisplatin. It was found that cell spreading caused a significant increase of impedance magnitude in the frequency range between 10kHz and 100kHz during 23h of incubation, which is reversed after 24h treatment with Cisplatin. This reversal is attributed to cell apoptosis, which is confirmed by microscopic observation of the cells

Charge-ordered ferromagnetic phase in manganites

A mechanism for charge-ordered ferromagnetic phase in manganites is proposed. The mechanism is based on the double exchange in the presence of diagonal disorder. It is modeled by a combination of the Ising double-exchange and the Falicov-Kimball model. Within the dynamical mean-field theory the charge and spin correlation function are explicitely calculated. It is shown that the system exhibits two successive phase transitions. The first one is the ferromagnetic phase transition, and the second one is a charge ordering. As a result a charge-ordered ferromagnetic phase is stabilized at low temperature.Comment: To appear in Phys. Rev.

Resident Wellness in US Ophthalmic Graduate Medical Education: The Resident Perspective

Importance: Wellness programs have become important strategies to combat burnout and depression among residents. However, the resident perspective on wellness in ophthalmic graduate medical education has not been solicited on a national level. Objectives: To report on residents\u27 views of wellness initiatives in ophthalmic graduate medical education and identify potential strategies for promoting resident wellness. Design, Setting, and Participants: In this national survey of ophthalmology residents in the United States, conducted from September 21 to November 3, 2017, all 1048 ophthalmology residents listed on the websites of ophthalmology residency programs accredited by the Accreditation Council for Graduate Medical Education were emailed an anonymous online survey consisting of 12 multiple-choice questions with options for free-text answers. Residents also received a mailed letter with a survey link and a $1 incentive, as well as 2 reminder emails. Survey responses were analyzed using descriptive statistics, and the free-text answers were categorized. Main Outcomes and Measures: Main outcomes include residents\u27 reports regarding their personal experiences with wellness during residency, support systems provided by their programs, and opportunities for improving wellness in ophthalmic graduate medical education. Results: Of 1048 residents, 241 (23.0%) responded to the survey. Most respondents (121 of 177 [68.4%]) reported that their programs faced an issue involving depression, burnout, or suicide among residents within the past year; 26.3% of respondents (61 of 232) reported being involved in a case when resident fatigue, burnout, or depression adversely affected a medical outcome or judgment. Fewer than half of the respondents (110 of 241 [45.6%]) reported that their residency programs placed moderate or major emphasis on promoting a culture of resident wellness, and only 26.7% (63 of 236) reported that their department had a formal resident wellness program. The most commonly cited barrier to resident wellness (59 of 236 [25.0%]) was a lack of time to attend wellness programs. Conclusions and Relevance: These results suggest that there is a substantial burden of burnout and depression among US ophthalmology residents and that there are opportunities to boost wellness in ophthalmic graduate medical education by making wellness curricula more accessible to residents and ensuring that residents have time to attend wellness programs

Parallel and I/O-efficient randomisation of massive networks using global curveball trades

Graph randomisation is a crucial task in the analysis and synthesis of networks. It is typically implemented as an edge switching process (ESMC) repeatedly swapping the nodes of random edge pairs while maintaining the degrees involved [23]. Curveball is a novel approach that instead considers the whole neighbourhoods of randomly drawn node pairs. Its Markov chain converges to a uniform distribution, and experiments suggest that it requires less steps than the established ESMC [6]. Since trades however are more expensive, we study Curveball’s practical runtime by introducing the first efficient Curveball algorithms: the I/O-efficient EM-CB for simple undirected graphs and its internal memory pendant IM-CB. Further, we investigate global trades [6] processing every node in a single super step, and show that undirected global trades converge to a uniform distribution and perform superior in practice. We then discuss EM-GCB and EMPGCB for global trades and give experimental evidence that EM-PGCB achieves the quality of the state-of-the-art ESMC algorithm EM-ES [15] nearly one order of magnitude faster

Production of n-propyl acetate by reactive distillation : experimental and theoretical study

First steps of the development of a catalytic reactive distillation process for the production of n-propyl acetate based on experiments and simulations are proposed. The kinetics for homogeneously (sulphuric acid) and heterogeneously (Amberlyst 15) catalysed reaction were investigated and the constants for a pseudo-homogeneous model are presented. Pilot plant experiments were performed using a homogeneous strong acid catalyst in a packed column. A top-column decanter is used to withdraw the aqueous phase and to reflux the organic phase. Simulation results are in good agreement with experimental data. Thermodynamics nonidealities are taken into account using VLE and LLE NRTL interaction parameters. Alcohol conversion and n-propyl acetate purity may be dramatically increased just by adding to the pilot plant a stripping section in an additional column: six different configurations are identified to achieve such a production. The startup is studied in order to determine the best strategy to achieve steady-state conditions. The strong influence of the composition of the initial charging in the decanter can be seen and an initial charging of the two-phase top product leads to the fastest startup

Hund's rule and metallic ferromagnetism

We study tight-binding models of itinerant electrons in two different bands, with effective on-site interactions expressing Coulomb repulsion and Hund's rule. We prove that, for sufficiently large on-site exchange anisotropy, all ground states show metallic ferromagnetism: They exhibit a macroscopic magnetization, a macroscopic fraction of the electrons is spatially delocalized, and there is no energy gap for kinetic excitations.Comment: 17 page