基于改进BiSeNetV2的裂缝检测与识别

裂缝作为固体材料中较为常见的某种不连续现象,是固体结构破坏的开始,及时对裂缝进行识别和检测,并对检测结果进行分析,采取相对应的措施,能够较好地防止事故发生,保障工程作业中的安全。目前裂缝识别主要依靠人工检测,存在劳动强度大、耗时长、精确度不高、危险、耗费高等问题,为此基于数字图像处理技术的裂缝智能识别被广泛研究,然而裂缝表面纹理不规则、噪声的复杂信息,影响了识别精度。为了解决常见固体材料的裂缝智能识别问题,提出了以轻量级语义分割网络模型BiSeNetV2来进行裂缝自动检测,同时自主构建裂缝数据集。实验表明,改进后的裂缝识别模型识别精度提升了7.6%。基于BiSeNetV2的裂缝识别模型,能对裂缝进行精准检测和识别,解决人工识别存在的各类问题。     

Crack Growth Prediction by Manifold Method

The prediction of crack growth is studied by the manifold method. The manifold method is a new numerical method proposed by Shi. This method provides a unified framework for solving problems dealing with both continuums and jointed materials. It can be considered as a generalized finite-element method and discontinuous deformation analysis. One of the most innovative features of the method is that it employs both a physical mesh and a mathematical mesh to formulate the physical problem. The physical mesh is dictated by the physical boundary of a problem, while the mathematical mesh is dictated by the computational consideration. These two meshes are interrelated through the application of weighting functions. In this study, a local mesh refinement and auto-remeshing schemes are proposed to extend the manifold method. The proposed model is first verified by comparing the numerical results with the benchmark solutions, and the results show satisfactory accuracy. The crack growth problems and the stress distributions are then investigated. The manifold method is proposed as an attractively new numerical technique for fracture mechanics analysis.     

Determination of power absorption in man exposed to high frequency electromagnetic fields by thermographic measurements on scale models

Ultrafiltrable serum uric acid (u.a.) was determined by ultrafiltration under in vivo conditions in humans using a reliable technique described in detail. It could be demonstrated that u.a. binding to macromolecules occurs in healthy humans (controls) and in patients with renal calcium stones. The percentage of free u.a. in controls (n=60) averages 86.2 +/- 0.9 SEM. With increasing age, bound u.a. rises slightly. On the other hand, younger (less than 40 years) stone patients have significantly more bound u.a. than matched controls (80.7 +/- 1.0 SEM; p less than 0.001), whereas this is not found in elderly patients. The degree of binding is not related to concentration of plasma proteins but inversely related to free fatty acid concentration in healthy controls (r= -0.52; p less than 0.01). It is suggested that no augmentation of tubular u.a. filtered by the glomeruli could have occurred. The origin of fasting hyperuricosuria shown earlier to be a prominent feature of young renal calcium stone formers is yet unknown.     

Radio frequency hearing: electrostrictive detection and bone conduction

A hearing aid patented by C. R. Schafer and supposedly based on detection of an amplitude-modulated carrier wave in the auditory cortex was re-examined. It is shown here that the hearing aid actually works by bone conduction of sound. It is concluded that detection of the modulation signal occurs by electrical nonlinearities and electrostriction in the bones of the face and skull.     

Crack closure load measurements for microcracks developed during the fatigue of Al 2219-T851

A compliance technique is utilized to determine the closure load for surface microcracks of one grain size and smaller produced by fully reversed loading fatigue of Al 2219-T851. Specimens are fatigued in flexure in air at 5, 18, and 45 pct relative humidities. Scanning electron microscopy is then utilized to measure crack compliance for selected microcracks and crack closure load is inferred from the break point in the linear relationship between crack opening and applied stress. For zero applied load the microcracks are found to be partially opened and a linear relationship is found between the closure load measured for the microcracks and the zero load crack opening normalized to crack length. This relationship holds regardless of the ambient humidity during fatigue, although there are significant changes in the zero load crack openings developed with humidity. An empirical relationship between the irregularity of the microcrack propagation path as affected by humidity and crack opening at zero load is also identified, which can be used to estimate crack closure load from crack dimensional parameters measured at the specimen surface.     

Intracellular fluorescence polarization measurements by the Cellscan system: detection of cellular activity in autoimmune disorders

BACKGROUND: Sodium retention is often a precursor to hospitalization in people with heart failure (HF). Lack of compliance with medications and with dietary sodium restrictions affects sodium retention. OBJECTIVES: The purpose of this study was to evaluate the reliability and validity of the Beliefs about Medication Compliance Scale and the Beliefs about Dietary Compliance Scale. METHODS: The Beliefs about Medication Compliance Scale and the Beliefs about Dietary Compliance Scale are instruments we developed specifically to measure beliefs about compliance with behaviors that affect sodium retention in persons with HF. The scales, based on the Health Belief Model, were designed from a review of literature and from self-reports of people with HF. A convenience sample of 101 people with HF completed the scales. RESULTS: Internal consistency reliability was satisfactory. Factor analysis provided initial support for construct validity of the scales. CONCLUSIONS: Future testing of the scales is needed in more diverse populations. The scales can then be used to test interventions tailored to individual subjects' beliefs about compliance.