Venus Lander Design

The students designed an Entry, Descent, and Landing (EDL) system for a lander to reach the surface of Venus. The students used a combination of 3D modelling and programming to design the EDL within given constraints under specific tolerances. An EDL takes into consideration entry flight dynamics, aeroheating, and landing systems. The EDL was divided into three stages (see below). The separation of stages was designed to address unique challenges found at different points throughout the EDL. The primary objective of the first stage was to minimize the heat associated with the entry velocity to the payload. The second stage implemented a parachute to reduce velocity such that the descent time criteria could be met. The third stage involved landing design. Through the use of six simultaneous differential equations, the flight of the vehicle was determined. The system was optimized by modifying craft parameters and initial conditions to meet objectives. After optimization, the revised values of position and velocity were obtained at every time step during descent. The vehicle velocity was used to calculate the heat rate to the heat shield of the entry vehicle. Through the use of a parachute, drag was increased to extend the time of flight and to slow the vehicle for landing. Designs were implemented to minimize impact force to the lander and maintain proper orientation during landing.https://scholarscompass.vcu.edu/capstone/1204/thumbnail.jp

Simultaneous polymerization and molding of Pyrrone polymers

Simultaneous polymerization and hot pressing of Pyrrone polymer

Deconstructing Myths About Rap Music

U melioracijskim radovima na mediteranskom kršu Hrvatske iznimno je važno dugoročno planiranje. Ozibljnu prepreku svim radovima stvaraju požari otvorenog prostora, u velikom broju antropogenog porijekla. Agrošumarstvo je analiziran kao kompleksni sustav koji ima široku amplitudu adaptacije na različite uvjete, te kao sustav koji na unikatan naćin može smanjiti dihtomiju šumarstva i lokalnih zajednica, te potaknuti razvoj gospodarstva mediteranskog krša Hrvatsk

Anisotropic particles at liquid interfaces

In this thesis we study the adsorption dynamics and self-assembly of anisotropic particles at a liquid-liquid interface. Firstly, we couple a Langevin dynamics model with the high-resolution finite element analysis software package Surface Evolver, which explicitly includes interfacial deformations, to study the adsorption dynamics of ellipsoidal particles. Transient contact line pinning due to nanoscale defects on the particle surface are also included by renormalising particle friction coefficients and using dynamic contact angles relevant to the adsorption timescale. We reproduce the monotonic variation of particle orientation with time that is observed experimentally and are able to quantitatively model the adsorption dynamics for some experimental ellipsoidal systems but not others. However, even for the latter case, our model accurately captures the adsorption trajectory (i.e., particle orientation vs. height) of said particles.Secondly, we extend our theoretical model to study cylindrical particles with the goal of using the adsorption kinetics of cylindrical nanorods at a liquid interface as a novel alternative route for assembling vertically aligned nanorod arrays. We find that the final orientation of non-neutrally wetting cylindrical nanorods is determined by their initial attack angle when they contact the liquid interface. Furthermore, the range of attack angles leading to the end-on state is maximised when nanorods approach the liquid interface from the bulk phase that is more energetically favorable.Finally, we move from the role anisotropy plays in the adsorption process to investigating how particle anisotropy can be utilized to direct the self-assembly of particles adsorbed at a liquid-liquid interface. Specifically, by modeling undulating hexagonal-like platelets and changing the relative phase axis of the undulation’s peaks and the hexagonal particles vertices, we can direct the assembly to a number of different self-assembled ground states including hexagonal close packed, honeycomb and kagome lattices

Towards the Development of Efficient and Economical Short Span Modular Bridges

The Federal Highway Administration\u27s National Bridge Index consists of over 600,000 bridges. Of these bridges, over 25% are considered either structurally deficient or functionally obsolete. While several state bridge departments have standard designs for bridge components in order to speed up the design process in replacing these bridges, few have standard designs for the bridge superstructure.;This work investigates current practices and trends in the design of short span bridges through the use of a survey. The survey was presented to the bridge department of every state in the country and responses were collected from 86% of these states. Based on the responses to these surveys, two courses were pursued in this work: the research and grading of both existing and developing modular bridge technologies that have application in short span steel bridges and the development of standard short span steel bridge superstructures using conventional design approaches.;In collaboration with the American Iron and Steel Institute\u27s Short Span Steel Bridge Alliance and other professionals in the bridge industry, a collection of modular bridge systems and elements were compiled and researched. Based on the Federal Highway Administration\u27s Highways for LIFE initiative, which promotes the development of Long-lasting highway infrastructure using Innovations to accomplish Fast construction of Efficient and safe highways and bridges, a grading system was developed for professionals in the industry to grade the major modular bridge systems researched. Based on the grading of these systems, a system will be further developed into a set of standardized short span bridge designs.;Second, standard short span steel bridge designs were developed to create a design aid for bridge engineers. In these designs, bridges with spans ranging from 40 feet to 140 feet in 5 foot increments were developed for rolled steel sections, homogeneous steel plate girder sections and hybrid steel plate girder sections. The rolled sections were designed using two design approaches: the lightest weight possible and the lightest weight possible with a limited section depth. Based on these designs, a suite of rolled sections were selected to be efficient sections of larger span ranges. This limited suite provides the opportunity for stock piling common rolled steel girder sections. Without needing to order the fabrication of the rolled girder sections, a more efficient transition from design to construction can be achieved. The plate girder sections were designed with a limited depth and utilizing a set of limited plate sizes to allow for the stock piling of common steel plate sizes. These designs will also act as a framework for future design plans using a modular bridge system

Attitudes to depression and its treatment in primary care

Background Undertreatment of depression in primary care is common. Efforts to address this tend to overlook the role of patient attitudes. Our aim was to validate and describe responses to a questionnaire about attitudes to depression and its treatment in a sample with experience of moderate and severe depressive episodes. Method Cross-sectional survey of 866 individuals with a confirmed history of an ICD-10 depressive episode in the 12 months preceding interview, recruited from 7271 consecutive general practitioner (GP) attendees in 36 general practices in England and Wales. Attitudes to and beliefs about depression were assessed using a 19-item self-report questionnaire. Results Factor analysis resulted in a three-factor solution: factor 1, depression as a disabling, permanent state; factor 2, depression as a medical condition responsive to support; and factor 3, antidepressants are addictive and ineffective. Participants who received and adhered to antidepressant medication and disclosed their depression to family and friends had significantly lower scores on factors 1 and 3 but higher scores on factor 2. Conclusions People with moderate or severe depressive episodes have subtle and divergent views about this condition, its outcome, and appropriate help. Such beliefs should be considered in primary care as they may significantly impact on help seeking and adherence to treatment

Re-locating media production

It was arguably easier in the past to pin down media production in medium- or content-specific locales, such as the studio, the newsroom or the set. Contemporary processes of media convergence have dramatically opened up the ‘what’ and ‘where’ of media production to include all manner of quotidian practices and ephemeral places. This special issue however pushes back against the idea that contemporary landscapes of media production have been flattened. Each of the articles collected here accounts for significant transformations in media practices nearer to those which we would conventionally associate with media production, yet which are also potentially left behind in the rush to describe, theorize, celebrate and critique trends such as ‘produsage’, ‘prosumption’ and participatory media culture. Taken together, the papers in this special issue provide new insights into the locations and re-locations of contemporary media production across new and under-researched liminal and peripheral geographies, and around new and unexpected objects