7,660 research outputs found

    Modeling of strain in multifilamentary wires deformed by thermal contraction and transverse forces

    Get PDF
    A previously published analytical model that describes a simplified wire geometry with three stacked cylinders is compared with finite element model calculations. The thermal strain from the matrix on the superconducting filaments is considered first. It appears that the analytical model is able to describe the strain that occurs in the filaments relatively accurate. Especially the radial dependence of the strain if a central core of normal material is present, is described quit well by the analytical model. The strain inside a wire surrounded by epoxy and subjected to a transverse load is almost uniform and can be approximated with an analytical model too. When yielding is involved to simulate a more localised transverse load inside a multifilamentary wire it is necessary to consider a numerical model

    Spatial Externalities and Vector-Borne Plant Diseases: Pierce’s Disease and the Blue-Green Sharpshooter in the Napa Valley

    Get PDF
    Pierce’s Disease (PD) is a bacterial disease that can kill grapevines over a span of one to three years. In this paper, we examine and model PD and vector control decisions made at the vineyard level in the Napa Valley in an effort to understand how the pest and disease affect individual growers, and to examine spatial externality issues and potential benefits from cooperation between adjacent vineyards. The model that we created adds to the literature by (a) treating grape vines as capital stocks that take time to reach bearing age and thus cannot be immediately replaced in the event of becoming diseased. We also (b) relax the assumption of an interior solution by examining the boundaries of parameter space for which winegrape growing is profitable and thus allowing growers to abandon land if it is not. We also explore (c) the effect of changing different policy parameters, such as PD control and vine replacement costs. Finally (d) we examine the potential benefits of cooperation between growers to manage vector populations, and determine that coordinated vector control could help riparian-adjacent growers to lessen grapevine losses and land abandonment, and thus to remain profitable in times of high PD pressure.Pierce’s Disease, winegrapes, perennial crop modeling, agricultural pests and diseases, optimal control theory, Crop Production/Industries, Production Economics, Resource /Energy Economics and Policy, Q12, Q24, C61,

    The Benefits and Costs of Alternative Policies for the Management of Pierce's Disease: A Case Study of the Blue-Green Sharpshooter in the Napa Valley

    Get PDF
    Replaced with revised version of poster on 07/23/10.Production Economics, Resource /Energy Economics and Policy,

    CAD for College: Switching to Onshape for Engineering Design Tools

    Get PDF
    Engineering Design Tools aims to teach students to use industry standard CAD tools in the context of a design and build course. Previous versions of the course have been taught utilizing Creo Parametric. To alleviate install concerns, distributed team work, and the challenges of learning Creo in a short time frame, the class transitioned to utilizing Onshape. To quote the Onshape website - “Onshape is the first CAD system built for teams. Students can work in groups and edit models together simultaneously. Teachers can distribute assignments, review work and give feedback with ease. Additionally, Onshape keeps a complete history of changes so students will never accidentally lose work or overwrite each other\u27s data.” [1] As Onshape was only released in 2014, there isn’t significant adoption in industry. This is a concern that students and the department faculty share. The goal was to increase focus on CAD for College. By utilizing a package that can easily be used in other aspects of a student’s college career, they might be more likely to “use it or lose it”. This paper will address how the course incorporates concepts of lifelong learning to facilitate students expanding the topics learned in class to other CAD platforms that may be more desirable on a resume

    THE ROLE OF PSYCHOSOCIAL FACTORS ON PRE AND POSTOPERATIVE PAIN IN PATIENTS WITH FEMORAL ACETABULAR IMPINGEMENT

    Get PDF
    Femoral acetabular impingement (FAI) is a bony hip condition that often results in tears to the acetabular labrum. Patients with FAI experience pain, decreased function, and quality of life. FAI and its’ sequela are treated definitively with hip arthroscopy. Hip arthroscopy is being performed with increasing frequency, and while most patients respond favorably, a subset of 10-20% of patients have suboptimal outcomes. Previous research suggests that mental status may be a primary driver in the way patients with FAI respond to and feel pain. Measures of mental status include the presence of mood disorders and psychosocial patient reported outcomes (PROs). Psychosocial constructs that have yet to be examined in patients with FAI include self-efficacy, kinesophobia, and pain catastrophizing. The Pain Self-Efficacy Questionnaire (PSEQ) gauges an individual’s confidence, or self-efficacy, in their ability to complete tasks despite their current pain. Previous research has established that a patient’s self-efficacy is an important determinant of long-term success following orthopedic surgery. Kinesophobia, measured via the Tampa Scale for Kinesiophobia (TSK), is a measure of movement-related fear. In contrast to self-efficacy, fear of movement has been identified as a predictor of early success following orthopedic surgery. Lastly, pain catastrophizing is a set of maladaptive behaviors including ruminating on pain, feeling helpless to overcome painful situations, and magnifying the circumstances surrounding the painful experience. Catastrophizing behaviors, measured via the Pain Catastrophizing Scale (PCS), have been repeatedly linked to increased pain and decreased functionality in a variety of orthopedic populations. To date, the relationship between these psychosocial variables and pain has not been examined in patients with FAI. The primary aim of this dissertation was to evaluate the role of psychosocial factors on pre and postoperative pain in patients with FAI undergoing hip arthroscopy. To accomplish this aim we performed a series of three studies. The first study was a retrospective chart review to determine the prevalence of mental health disorders and compare preoperative clinical presentation between patients with and without mental health disorders. The second was a cross-sectional study designed to determine if any psychosocial variables could predict preoperative hip pain. The final study utilized a longitudinal, cohort design. Patients were tested preoperatively and at 12-weeks postoperative. The primary outcomes measured were self-efficacy, kinesiophobia, pain catastrophizing, and hip pain at rest and during activity measured via a visual analog scale (VAS). The purpose of this study was to determine the effect of preoperative psychosocial variables on postoperative pain, and to determine if these variables were predictive of persistent postoperative pain three months following hip arthroscopy. Based on the results from these studies we can conclude the following: 1) Mental health disorders are more common in patients with FAI than other orthopedic populations, and self-reported pain and function are worse in this subset of patients, but neither symptom chronicity nor the severity of joint deformity differs; 2) Low self-efficacy is predictive of worse preoperative pain in patients with FAI; and 3) Patients with high preoperative pain catastrophizing or low self-efficacy are more likely to have increased postoperative pain. Low preoperative self-efficacy is predictive of persistent hip pain during activity three months following hip arthroscopy, while low self-efficacy and mental health disorders are predictive of persistent hip pain at rest. Future studies are necessary to develop and implement interventions targeting low self-efficacy and elevated catastrophizing in patients undergoing hip arthroscopy to improve patient outcomes for this high-risk group

    Visual Perceptual Difficulties and Under-Achievement at School in a Large Community-Based Sample of Children

    Get PDF
    Difficulties with visual perception (VP) are often described in children with neurological or developmental problems. However, there are few data regarding the range of visual perceptual abilities in populations of normal children, or on the impact of these abilities on children's day-to-day functioning. Methods Data were obtained for 4512 participants in an ongoing birth cohort study (Avon Longitudinal Study of Parents and Children; ALSPAC). The children's mothers responded to questions designed to elicit indications of visual perceptual difficulties or immaturity, when their children were aged 13 years. We examined associations with standardised school test results in reading and in mathematics at age 1314 years (SATS-KS3), accounting for potential confounders including IQ. Results Three underlying factors explained half the variance in the VP question responses. These correlated best with questions on interpreting cluttered scenes; guidance of movement and face recognition. The adjusted parameter estimates (95% CI) for the cluttered-scenes factor (0.05; 0.02 to 0.08; p<0.001) suggested positive associations with the reading test results whilst that for the guidance-of-movement factor (0.03; 0.00 to 0.06; p = 0.026) suggested positive association with the mathematics results. The raw scores were associated with both test results. Discussion VP abilities were widely distributed in this sample of 13-year old children. Lower levels of VP function were associated with under-achievement in reading and in mathematics. Simple interventions can help children with VP difficulties, so research is needed into practicable, cost-effective strategies for identification and assessment, so that support can be targeted appropriately
    corecore