239 research outputs found

    Quantitative Electromagnetic Modeling and NDE of Carbon-Carbon Composites

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    There is much need for investigating the use of eddy-current inspection with advanced composite materials, including graphite-epoxy and carbon-carbon. One of the problems in evaluating the performance of eddy-current inspection is that it is often difficult to characterize the conductivity of the fiber composite material. For example, when the material is composed of conducting fibers and a nonconducting matrix, as is the case with graphite-epoxy, the overall conductivity is a complicated quantity that depends on fiber conductivity, fiber density, fiber layup order (sample geometry), and the frequency at which the eddy-currents are being excited. Dependency on frequency and layup order, in particular, give the investigator much difficulty in interpreting any eddy-current data from experiments. If these two factors cause a weak effect, there may be a suitable range of frequencies for inspecting the material via application of somewhat standard techniques

    Meadow spittlebug control with new insecticides

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    Application of Volume-Integral Models to Steam Generator Tubing

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    The nuclear power industry faces the serious challenge of convincing a skeptical public and regulatory agencies that it can operate safely and efficiently. Nondestructive evaluation (NDE) plays a significant role in this task, and computer modeling is playing a significant role in NDE. The industry now realizes the value of using such modeling to replace expensive experimental tests, as well as to design equipment, and interpret results. Eddy-currents have a traditional place in the inspection of steam generator tubing, and the industry seeks improved tools for such inspections. In this paper, we describe progress in developing a general axisymmetric model that will be part of the volume-integral code, VIC-3D1. This model will be capable of analyzing tubes with tube supports and rolled-expansion transition zones. Features such as magnetite, sludge, etc., will be included, and materials may be either ferromagnetic or non-magnetic. The model described in this paper will include only differential (or absolute) bobbin coils. Flaws can be of three types: (1) axisymmetric (such as circumferential rings), (2) the usual thin, axially-oriented, crack that is part of VIC-3D’s present library, and (3) user-defined flaws, such as inter-granular attack (IGA)

    Predicting Hip Fracture Type With Cortical Bone Mapping (CBM) in the Osteoporotic Fractures in Men (MrOS) Study.

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    Hip fracture risk is known to be related to material properties of the proximal femur, but fracture prediction studies adding richer quantitative computed tomography (QCT) measures to dual-energy X-ray (DXA)-based methods have shown limited improvement. Fracture types have distinct relationships to predictors, but few studies have subdivided fracture into types, because this necessitates regional measurements and more fracture cases. This work makes use of cortical bone mapping (CBM) to accurately assess, with no prior anatomical presumptions, the distribution of properties related to fracture type. CBM uses QCT data to measure the cortical and trabecular properties, accurate even for thin cortices below the imaging resolution. The Osteoporotic Fractures in Men (MrOS) study is a predictive case-cohort study of men over 65 years old: we analyze 99 fracture cases (44 trochanteric and 55 femoral neck) compared to a cohort of 308, randomly selected from 5994. To our knowledge, this is the largest QCT-based predictive hip fracture study to date, and the first to incorporate CBM analysis into fracture prediction. We show that both cortical mass surface density and endocortical trabecular BMD are significantly different in fracture cases versus cohort, in regions appropriate to fracture type. We incorporate these regions into predictive models using Cox proportional hazards regression to estimate hazard ratios, and logistic regression to estimate area under the receiver operating characteristic curve (AUC). Adding CBM to DXA-based BMD leads to a small but significant (p < 0.005) improvement in model prediction for any fracture, with AUC increasing from 0.78 to 0.79, assessed using leave-one-out cross-validation. For specific fracture types, the improvement is more significant (p < 0.0001), with AUC increasing from 0.71 to 0.77 for trochanteric fractures and 0.76 to 0.82 for femoral neck fractures. In contrast, adding DXA-based BMD to a CBM-based predictive model does not result in any significant improvement.The Osteoporotic Fractures in Men (MrOS) Study is supported by National Institutes of Health funding. The following institutes provide support: the National Institute on Ageing (NIA), the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), the National Center for Advancing Translational Sciences (NCATS), and NIH Roadmap for Medical Research under the following grant numbers: U01 AG027810, U01 AG042124, U01 AG042139, U01 AG042140, U01 AG042143, U01 AG042145, U01 AG042168, U01 AR066160, and UL1 TR000128. GMT, AHG, DMB and KESP contributed to the conception and design of the study. All authors were involved in the analysis or interpretation of the data, contributed to the manuscript, and approved the final version. KESP acknowledges the support of the NIHR Biomedical Research Centre, Cambridge. KESP received funding from Arthritis Research UK (ARUK ref. no. 20109). GMT takes responsibility for the integrity of the data analysis.This is the final version of the article. It first appeared from Wiley via http://dx.doi.org/10.1002/jbmr.255

    Kentucky Tax Law, Second Edition

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    A reference for Kentucky lawyers on real and personal property taxation, Kentucky sales and use taxation, Kentucky individual income taxation, corporate income taxation, and procedures before the Kentucky Board of Tax Appeals

    Focal osteoporosis defects play a key role in hip fracture

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    BACKGROUND\textbf{BACKGROUND}: Hip fractures are mainly caused by accidental falls and trips, which magnify forces in well-defined areas of the proximal femur. Unfortunately, the same areas are at risk of rapid bone loss with ageing, since they are relatively stress-shielded during walking and sitting. Focal osteoporosis in those areas may contribute to fracture, and targeted 3D measurements might enhance hip fracture prediction. In the FEMCO case-control clinical study, Cortical Bone Mapping (CBM) was applied to clinical computed tomography (CT) scans to define 3D cortical and trabecular bone defects in patients with acute hip fracture compared to controls. Direct measurements of trabecular bone volume were then made in biopsies of target regions removed at operation. METHODS\textbf{METHODS}: The sample consisted of CT scans from 313 female and 40 male volunteers (158 with proximal femoral fracture, 145 age-matched controls and 50 fallers without hip fracture). Detailed Cortical Bone Maps (c.5580 measurement points on the unfractured hip) were created before registering each hip to an average femur shape to facilitate statistical parametric mapping (SPM). Areas where cortical and trabecular bone differed from controls were visualised in 3D for location, magnitude and statistical significance. Measures from the novel regions created by the SPM process were then tested for their ability to classify fracture versus control by comparison with traditional CT measures of areal Bone Mineral Density (aBMD). In women we used the surgical classification of fracture location ('femoral neck' or 'trochanteric') to discover whether focal osteoporosis was specific to fracture type. To explore whether the focal areas were osteoporotic by histological criteria, we used micro CT to measure trabecular bone parameters in targeted biopsies taken from the femoral heads of 14 cases. RESULTS\textbf{RESULTS}: Hip fracture patients had distinct patterns of focal osteoporosis that determined fracture type, and CBM measures classified fracture type better than aBMD parameters. CBM measures however improved only minimally on aBMD for predicting any hip fracture and depended on the inclusion of trabecular bone measures alongside cortical regions. Focal osteoporosis was confirmed on biopsy as reduced sub-cortical trabecular bone volume. CONCLUSION\textbf{CONCLUSION}: Using 3D imaging methods and targeted bone biopsy, we discovered focal osteoporosis affecting trabecular and cortical bone of the proximal femur, among men and women with hip fracture.Arthritis Research UK (grant no. ARC17822) and Cambridge National Institute for Health Research (NIHR) Biomedical Research Centre

    High Temperature Thermopower in La_{2/3}Ca_{1/3}MnO_3 Films: Evidence for Polaronic Transport

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    Thermoelectric power, electrical resistivity and magnetization experiments, performed in the paramagnetic phase of La_{2/3}Ca_{1/3}MnO_3, provide evidence for polaron-dominated conduction in CMR materials. At high temperatures, a large, nearly field-independent difference between the activation energies for resistivity (rho) and thermopower (S), a characteristic of Holstein Polarons, is observed, and ln(rho) ceases to scale with the magnetization. On approaching T_c, both energies become field-dependent, indicating that the polarons are magnetically polarized. Below T_c, the thermopower follows a law S(H) prop. 1/rho (H) as in non saturated ferromagnetic metals.Comment: 10 pages, 5 .gif figures. Phys. Rev B (in press

    Contexting Koreans: Does the High/Low Model Work?

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    South Korea is assumed to be a high-context culture with extensive shared information and an emphasis on relationships in doing business. The follow ing study reported here tests this assumption and illustrates similarities and differences between Korean and American writers in an attempt to document language differences between high- and low- context societies. Data in the texts studied did not confirm the high/low contextfeatures expected. South Korean texts showed more similarities to than differences from the American texts, and the language features found suggest a more complex context situa tion than the high/low context model may be able to accommodate.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66563/2/10.1177_108056999806100403.pd

    Validation of the VE1 immunostain for the BRAF V600E mutation in melanoma

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    BACKGROUND: BRAF mutation status, and therefore eligibility for BRAF inhibitors, is currently determined by sequencing methods. We assessed the validity of VE1, a monoclonal antibody against the BRAF V600E mutant protein, in the detection of mutant BRAF V600E melanomas as classified by DNA pyrosequencing. METHODS: The cases were 76 metastatic melanoma patients with only one known primary melanoma who had had BRAF codon 600 pyrosequencing of either their primary (n = 19), metastatic (n = 57) melanoma, or both (n = 17). All melanomas (n = 93) were immunostained with the BRAF VE1 antibody using a red detection system. The staining intensity of these specimens was scored from 0 to 3+ by a dermatopathologist. Scores of 0 and 1+ were considered as negative staining while scores of 2+ and 3+ were considered positive. RESULTS: The VE1 antibody showed a sensitivity of 85% and a specificity of 100% as compared to DNA pyrosequencing results. There was 100% concordance between VE1 immunostaining of primary and metastatic melanomas from the same patient. V600K, V600Q, and V600R BRAF melanomas did not positively stain with VE1. CONCLUSIONS: This hospital-based study finds high sensitivity and specificity for the BRAF VE1 immunostain in comparison to pyrosequencing in detection of BRAF V600E in melanomas

    Poor reproducibility of compression elastography in the Achilles tendon: same day and consecutive day measurements.

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    OBJECTIVE To determine the reproducibility of compression elastography (CE) when measuring strain data, a measure of stiffness of the human Achilles tendon in vivo, over consecutive measures, consecutive days and when using different foot positions. MATERIALS AND METHODS Eight participants (4 males, 4 females; mean age 25.5 ± 2.51 years, range 21-30 years; height 173.6 ± 11.7 cm, range 156-189 cm) had five consecutive CE measurements taken on one day and a further five CE measures taken, one per day, at the same time of day, every day for a consecutive 5-day period. These 80 measurements were used to assess both the repeatability and reproducibility of the technique. Means, standard deviations, coefficient of variation (CV), Pearson correlation analysis (R) and intra-class correlation coefficients (ICC) were calculated. RESULTS For CE data, all CVs were above 53%, R values indicated no-to-weak correlations between measures at best (range 0.01-0.25), and ICC values were all classified in the poor category (range 0.00-0.11). CVs for length and diameter measures were acceptably low indicating a high level of reliability. CONCLUSIONS Given the wide variation obtained in the CE results, it was concluded that CE using this specific system has a low level of reproducibility for measuring the stiffness of the human Achilles tendon in vivo over consecutive days, consecutive measures and in different foot positions
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