Degradation of Glass Fiber Reinforced Polyamide 6 Composites Throughout the Direct Long-Fiber Reinforced Thermoplastic Process

The direct long-fiber reinforced thermoplastic (D-LFT) process is a streamlined material processing technique which includes various types of equipment. It is imperative to understand how the process and its operating conditions affect degradation and thermal properties of the processed material for industry applications. This study investigates effects of process stages, extruder temperature, and screw speed on molecular weight and thermal properties of glass fiber reinforced polyamide 6 (PA6) composites throughout the D-LFT process. Viscosity number (VN) measurements, thermogravimetric analyses (TGA) and differential scanning calorimetry (DSC) analyses were performed on collected samples. In conclusion, it was found that thermo-oxidative degradation is the main degradation mechanism of the glass fiber reinforced PA6 composites during the D-LFT process. Therefore, minimizing temperature and residence time of the extruders as well as exposure time of plastificate to atmospheric conditions along the conveyer is an effective way to minimize degradation of PA6

A study of the digestibility of sorghum silage and oat straw

LD2668 .T4 1947 D68Master of Scienc

In an Irish Jaunting Car

https://digitalcommons.library.umaine.edu/mmb-ps/2875/thumbnail.jp

Three-dimensional multigrid algorithms for the flux-split Euler equations

The Full Approximation Scheme (FAS) multigrid method is applied to several implicit flux-split algorithms for solving the three-dimensional Euler equations in a body fitted coordinate system. Each of the splitting algorithms uses a variation of approximate factorization and is implemented in a finite volume formulation. The algorithms are all vectorizable with little or no scalar computation required. The flux vectors are split into upwind components using both the splittings of Steger-Warming and Van Leer. The stability and smoothing rate of each of the schemes are examined using a Fourier analysis of the complete system of equations. Results are presented for three-dimensional subsonic, transonic, and supersonic flows which demonstrate substantially improved convergence rates with the multigrid algorithm. The influence of using both a V-cycle and a W-cycle on the convergence is examined

The effect of pressure prehydration on the strength of hydraulic cement concrete

It appears that the rapidity of curing and the degree or ultimate strength of concrete can be influenced by both chemical and physical factors. The main function of the physical factors involved seems to be the creating of a more intimate combination of the cement and water which are the active ingredients. For example, finer grinding of the cement would present more surface area to the water; the application of heat would decrease the amount of surface tension of the water, in addition to speeding the chemical reaction, steam under pressure would force water into the porous particles of cement; and the retaining of water in the mix by protecting it from evaporation would insure a more complete hydration. It would logically follow that the application of pressure to force water into the cement particles would produce a more intimate combination of cement and water. The purposes of this investigation are as follows: (1) To determine if the use of pressure to force water into the cement particles will accelerate the curing of concrete. (2) To determine the optimum degree of pressure to be applied for a three-minute period. (3) To determine if the accelerated curing will yield a concrete which has a higher ultimate strength after a reasonable period. Tests of Set I are concerned with phases (1) and (2). Tests of Set II are a verification of the results of tests of Set l, under conditions of more rigid control. Tests of Set III performed in connection with phase (3). --Purpose and Object of Investigations, pages 4-5

Computation of transonic viscous-inviscid interacting flow

Transonic viscous-inviscid interaction is considered using the Euler and inverse compressible turbulent boundary-layer equations. Certain improvements in the inverse boundary-layer method are mentioned, along with experiences in using various Runge-Kutta schemes to solve the Euler equations. Numerical conditions imposed on the Euler equations at a surface for viscous-inviscid interaction using the method of equivalent sources are developed, and numerical solutions are presented and compared with experimental data to illustrate essential points

PrEP Use and Barriers to Use Among Adult and Young Sexual Minority Men in the United States

Pre-exposure prophylaxis (PrEP) was approved for all individuals 13 years of age and older in May 2018. However, research pertaining to uptake has mostly focused on adult sexual minority men (SMM), leaving out many barriers and facilitators that may exist for those under 18 years of age. Two of the most important precursors leading to PrEP uptake identified in prior research are the perception of self as a PrEP candidate and having intentions to begin PrEP. Developmental and dual processing theories suggest that individuals who are younger make behavioral decisions differently from those who are older. Developmental theories suggest that, compared to those who are older, those who are younger make decisions by placing more weight on social approval, as opposed to individual benefits. Dual processing theories suggest that, as individuals age, they utilize more ‘cold’ cognitive processing and conscious thought in their decision making; thus, those who are younger utilize more ‘hot’ affective processing. Taken together, theories of development and dual processing suggest that those who are younger may make decisions about PrEP use differently from those who are older. Current interventions aiming to increase PrEP uptake among adults may need to be altered to include the specific differences among decisions making in younger populations. As such, the aims of this dissertation were to: (1) examine PrEP use experience among both young sexual minority men (YSMM; ages 13-24) and SMM (25 years of age and up); (2a) investigate the role of age as a moderator between affective and cognitive dimensions of HIV risk perception as associated with self-perception of PrEP candidacy and PrEP intentions among YSMM who are at-risk for HIV seroconversion; and (2b) investigate the role of age as a moderator between perceived benefits of PrEP use and PrEP stigma as associated with PrEP intentions among YSMM. To achieve these aims, data were analyzed from a larger study of SMM living across the United States. As part of this project, participants first completed an online survey and then once enrolled, completed a baseline assessment. Utilizing data collected from the screener survey, in Study 1, I tested a series of hypotheses examining differences in PrEP use within an age-stratified sample of YSMM and adult SMM. In bivariate analyses, I found that PrEP utilization was lowest among those 13-24 years of age. In regression analyses, stratified by age group and predicting PrEP use (i.e., former, and current), compared to never having used PrEP, I found that the odds of being a current PrEP user increased by 31% for each year of age for YSMM. Additionally, I found that while controlling for age, YSMM who were on their parent or guardian’s medical insurance had decreased odds of PrEP use compared to those on their own health insurance. There were also various demographic and behavioral differences that distinguished PrEP use history within the two age groups. These differences included sexual orientation, race, ethnicity, relationship status, region, medical insurance, and recent behavioral and sexual risk. Taken together, the findings from the first aim suggest there are many variables that need to be further investigated before PrEP uptake among YSMM is likely to increase. Data for the second aim of this dissertation came from baseline data collected as part of the parent project, UNITE, a longitudinal cohort study examining the psychosocial and biological predictors of HIV seroconversion among SMM (UG3-AI133674). Utilizing these data, in Study 2, I investigated a series of theoretically grounded hypotheses predicting the associations between cognitive and affective dimensions of HIV risk and the two primary precursors to PrEP uptake (i.e., perceived PrEP candidacy, and PrEP intentions) among only YSMM (16-24 years of age, M = 21.2). I found that affective dimensions of HIV risk were significantly positively associated with PrEP candidacy and that this association was stronger among olderYSMM. Additionally, I found that cognitive dimensions of perceived HIV risk were significantly negatively associated with PrEP candidacy, and this association was weaker among older YSMM. Next, I tested affective and cognitive dimensions of HIV risk on PrEP intentions, mediated by perceived PrEP candidacy. I found support for perceived PrEP candidacy significantly mediating the associations between both affective and cognitive dimensions of perceived HIV risk and PrEP intentions. Lastly, I tested a model assessing whether age moderated the effects of perceived benefits of PrEP use and PrEP stigma on PrEP intentions. I found that perceived benefits of PrEP use were positively associated with PrEP intentions, and this association was stronger among older YSMM. In contrast, I found PrEP stigma was negatively associated with PrEP intentions, and this association was weaker among older YSMM. Findings from this dissertation highlight differences in factors that are known to change with increased age that significantly affects YSMM and may impede PrEP uptake. There are many potential places for interventions to be made at different levels, including clinical, medical, and public health and policy. In order for the HIV epidemic to end in the United States, changes at all levels may be necessary, including interventions that focus on both young SMM and their caregivers. These intervention adaptations and future research ideas are discussed in the conclusions, as well as the limitations to this research

Liberty, Property, Materiality : An historical archaeology of protest and resistance in later-eighteenth-century England

Ph. D. Thesis.The later eighteenth century (c.1763-1815) was a period of great social, economic and cultural upheaval in Britain. Drawing on a range of case studies from North-East England and London, drawn together through the life of Thomas Spence, this thesis explores how subaltern individuals and groups experienced, protested against, and resisted these upheavals, not just through public ‘flash-points’ such as riots but also routinely through quotidian objects and spaces in the everyday. To investigate case studies of everyday subaltern resistance, this thesis searches beyond elite produced textual accounts, which commonly obscure everyday forms of resistance, and instead pursues a multisource methodology integrating textual, material, and spatial sources. Through the critical examination of these sources in combination, a range of inconsistencies, ambiguities, and exaggerations appear suggesting the presence of underlying hidden tensions, anxieties, and dissent. This thesis then explores how these tensions were materialised in objects and places as component strategies articulating protest and resistance. Taken individually, the case studies present a series of highly nuanced micro-histories offering important insights into context-specific expressions of protest and resistance in later-eighteenth-century England. When read together, however, they suggest how material culture and space were widely understood, across diverse contexts, to offer important avenues for expressions of protest and resistance at the macro-scale. Between Marsden Grotto, Newcastle-upon-Tyne’s Town Moor, Spencean London and the Wilkes and Liberty movement, this thesis demonstrates how subalterns expressed their dissent and demands in common ways through objects, space and place. This thesis thus opens a new approach to the history and archaeology of protest and resistance, foregrounding subaltern experience and promoting a recognition of the pivotal roles played by material culture, space and place in the articulation of power, protest and resistance.AHR

Eastown! A report on how Aquinas College helped its local community reverse neighbor

The success story presented in the following narrative is offered not only as an inspiration and a gratifying tale of problems accurately identified and effectively dealt with, but more importantly this publication provides a basis for the use of lessons learned that can profitably serve other communities and agencies faced with the same or similar vexing concerns. The problem of nearby static or deteriorating neighborhoodshas plagued colleges, hospitals, and churches for many years. Now we have at least one tested approach to the perennial question, "What can our institution do to help save its neighborhood?" The strategies employed by Aquinas College in working with its contiguous community are not offered in the form of a blueprint. Rather, they are meant to serve as an aid in the formulation of the special approach called for in other similar but always unique situations. Nevertheless, it is possible to benefit from learning the details of the gratifying developments now proudly referred to as the Aquinas-Eastown experience. Even more promising is the offer that accompanies this publication. Aquinas College and Eastown Community Association have magnanimously agreed to share freely their hardwon expertise. With this book they offer to help individuals and groups to adapt to other settings the strategies applied in Eastown. On request they are willing to provide counsel and to supplement,as appropriate, this brief report of their pioneering response to neighborhood renewal

Educational innovation for infection control in Tanzania: Bridging the policy to practice gap

The incidence of hospital acquired infection in developing countries is between two to 20 times higher than in developed countries and is attributable to multiple causes. Evidence-based international policies and guidelines developed to improve infection prevention and control are often not used in practice in these countries. To combat this challenge, this article presents an innovative educational framework used to bridge the gap between policy written by global health agencies and the realities of practice in Tanzania