Assessment of aerodynamic performance of V/STOL and STOVL fighter aircraft

The aerodynamic performance of V/STOL and STOVL fighter/attack aircraft was assessed. Aerodynamic and propulsion/airframe integration activities are described and small and large scale research programs are considered. Uncertainties affecting aerodynamic performance that are associated with special configuration features resulting from the V/STOL requirement are addressed. Example uncertainties relate to minimum drag, wave drag, high angle of attack characteristics, and power induced effects

Adaptive Electricity Scheduling in Microgrids

Microgrid (MG) is a promising component for future smart grid (SG) deployment. The balance of supply and demand of electric energy is one of the most important requirements of MG management. In this paper, we present a novel framework for smart energy management based on the concept of quality-of-service in electricity (QoSE). Specifically, the resident electricity demand is classified into basic usage and quality usage. The basic usage is always guaranteed by the MG, while the quality usage is controlled based on the MG state. The microgrid control center (MGCC) aims to minimize the MG operation cost and maintain the outage probability of quality usage, i.e., QoSE, below a target value, by scheduling electricity among renewable energy resources, energy storage systems, and macrogrid. The problem is formulated as a constrained stochastic programming problem. The Lyapunov optimization technique is then applied to derive an adaptive electricity scheduling algorithm by introducing the QoSE virtual queues and energy storage virtual queues. The proposed algorithm is an online algorithm since it does not require any statistics and future knowledge of the electricity supply, demand and price processes. We derive several "hard" performance bounds for the proposed algorithm, and evaluate its performance with trace-driven simulations. The simulation results demonstrate the efficacy of the proposed electricity scheduling algorithm.Comment: 12 pages, extended technical repor

Preliminary performance estimates of a highly maneuverable remotely piloted vehicle

A computerized synthesis program has been used to assess the effects of various vehicle and mission parameters on the performance of a highly maneuverable remotely piloted vehicle (RPV) for the air-to-air combat role. The configuration used in the study is a trapezoidal-wing and body concept, with forward-mounted stabilizing and control surfaces. The study mission consists of an outbound cruise, an acceleration phase, a series of subsonic and supersonic turns, and a return cruise. Performance is evaluated in terms of both the required vehicle weight to accomplish this mission and combat effectiveness as measured by turning and acceleration capability. The report describes the synthesis program, the mission, the vehicle, and the results of sensitivity and trade studies

V/STOL concepts in the United States: Past, present, and future

Nonhelicopter types of V/STOL aircraft developed in the United States are reviewed, and some lessons learned from a selected number of concepts are highlighted. The AV-8B, which was developed by modifications to the British Harrier is the only current concept examined. Configurations proposed for the future subsonic, multimissing aircraft and the future supersonic fighter/attack aircraft are described. Emphasis is on these supersonic concepts

Preliminary performance estimates of an oblique, all-wing, remotely piloted vehicle for air-to-air combat

A computerized aircraft synthesis program has been used to assess the effects of various vehicle and mission parameters on the performance of an oblique, all-wing, remotely piloted vehicle (RPV) for the highly maneuverable, air-to-air combat role. The study mission consists of an outbound cruise, an acceleration phase, a series of subsonic and supersonic turns, and a return cruise. The results are presented in terms of both the required vehicle weight to accomplish this mission and the combat effectiveness as measured by turning and acceleration capability. This report describes the synthesis program, the mission, the vehicle, and results from sensitivity studies. An optimization process has been used to establish the nominal RPV configuration of the oblique, all-wing concept for the specified mission. In comparison to a previously studied conventional wing-body canard design for the same mission, this oblique, all-wing nominal vehicle is lighter in weight and has higher performance

REVIEW: Code Orange

Review of the young adult novel Code Orange, by Caroline B. Cooney

Perceptions of Barriers in Prosecuting Human Trafficking Cases

Human trafficking is a world-wide problem with many barriers. Human trafficking cases are criminal but are also a violation of human rights. Human trafficking victims are lured from their homes based on the allusion from the trafficker of a better life. The victims are then beaten, forces to use drugs, and essentially broken. Once the victim is broken they are forced to perform sexual acts. Due to the initial promises and threats the victims endure, they also suffered from fear of trusting others especially law enforcement as well as other psychological issues similar to that of a domestic violence victim. These emotional, physical, and psychological issues the victims face are key factors in the struggle’s prosecution faces when prosecuting human trafficking cases. This study will explore the perceptions of the prosecutors on the barriers they face when prosecuting human trafficking cases. The goal of this research is to identity the specific themed barriers in human trafficking cases through the perceptions of the individuals from the Attorney General’s office of Georgia. Specifically, the research will examine all the barriers the Attorney General’s office faces regarding the arrest, conviction, prosecution and sentencing of human trafficking cases. This study identified four themes to help the processing of human trafficking cases overall

Finite element analysis of shear resistant mechanisms for biolaminate interfaces

The Alligator gar possesses a flexible dermal armor consisting of overlapping ganoid scales. Each scale is a bilayer hydroxyapatite and collagen-based bio-laminate for protection against predation. The exoskeleton fish scale is comprised of a stiff outer ganoine layer, a characteristic sawtooth pattern at the interface and a compliant bone inner layer with all materials exhibiting a decreasing elastic modulus, yield strength and density through the thickness. Experiments on ganoid scales revealed properties such as damage mitigation and energy dissipation that are unique to biological dermal armor. The objective of this investigation is to develop a fundamental understanding of the stress response of a fish scale under tensile and shear loading conditions and to compute effective elastic properties. The effects of material grading and the influence of the geometrically and materially nonlinear interface between the ganoine and bone layers on the elastic properties were also considered. A three dimensional finite element method (FEM) was used by employing ABAQUS® code. The current work also investigated possible mechanisms associated with delamination resistance and energy dissipation of the bio-laminate structures. The model structure for the fish scale in the FEM was Alligator gar. The finite element analysis (FEA) is based on a microscopic representative volume element (RVE) of the fish scale with an overall thickness of 800 micron. The FEA RVE had one million uniform 8-micron cubical 8-node elements. The geometrically nonlinear sawtooth features are explicitly modeled. An elastic-plastic model described the nonlinear material response. The analysis focused on evaluating the nonlinear material response in terms of energy dissipation and stress redistribution at the ganoine-bone interface. The results indicate that a complex redistribution of stresses across the 800 micron thickness occurred due to functional gradation of properties, from the stiff mineralized ganoine to the soft bone layer. While the stress concentration was limited to the interface between the saw tooth and the surrounding bone layer, the average stresses in the ganoine layer were much lower as compared to the distributions in the bone layer. The internal energy at the ganoine-bone interface is reduced and energy is dissipated across the sawtooth junction points

Marine litter, microplastics and marine megafauna

Over the last sixty years, the development of synthetic and durable materials, namely plastic, coupled with a growing human population, has resulted in a rapid increase in the levels of anthropogenic debris in rivers, along coastlines and in the wider marine ecosystem. Currently, an estimated 4.8 to 12.7 million tons of plastic enter the oceans every year but this is expected to increase to between 9.6 and 25.4 million tons by 2025. As such, it is one of the most widely recognised pollution issues facing the planet due to its wide-ranging ecological and socio-economic implications. The main aims of this thesis were to i) examine citizen-science beach clean data to better understand the composition of anthropogenic litter deposited on British beaches by determining the most common items, materials, sources and pathways, and exploring the data for spatial patterns and temporal trends in litter density; ii) investigate an indirect pathway (trophic transfer) of microplastic (<5mm in size) ingestion in marine top predators by analysing scat (faeces) from captive grey seals (Halichoerus grypus) and the wild-caught fish they were fed upon; iii) explore the extent to which wild marine mammals ingest microplastics and consider the potential implications by examining the digestive tracts of 50 marine mammals from 10 species that stranded around the British coast; iv) develop a method of investigating dietary exposure of marine mammal top predators to microplastics, by combining scat-based molecular techniques (metabarcoding) with a microplastic isolation method. The research carried out for this thesis reveals that i) plastic is the main constituent of marine litter on British beaches and the majority of traceable items originate from land-based activities, such as public littering. The coasts of the southwest England and south Wales have the highest litter levels and certain items - small plastic fragments, plastic food packaging, wet wipes, polystyrene foam, balloons and large fishing net – are increasing; ii) trophic transfer is an indirect and under-studied, but potentially major, route of microplastic ingestion for marine top predators; iii) microplastics are ubiquitous within the digestive tracts of wild marine mammals stranded around the British coast but the overall low abundance suggests they may be egested; iv) the rate of microplastic ingestion by marine top predators may be related to the type of prey they consume but further work is needed to assess the impacts of this omnipresent pollutant.Natural Environment Research Council (NERC