pitting

点蚀
  • 文章类型: Journal Article
    今天,有许多诊断方法和先进的测量技术,能够正确诊断和评估齿轮的类型和磨损程度(齿轮,泵,等。).本研究对油泵原型(3PW-BPF-24)的齿轮的表面缺陷进行了分析。测试对象在受控的操作和环境参数下操作一定的小时数。对表面层的损坏是由疲劳现象和先前的热化学处理引起的。基于扩散层体积中残余奥氏体的显著百分比(~30%),关于热化学处理过程的次优参数(与分析小齿轮的化学成分有关)得出了一个假设结论。大量的研究表明,大量的残余奥氏体的存在导致齿面硬度的降低,脆性裂纹的开始,疲劳强度急剧下降,脆性的增加和在操作过程中形成表面层裂纹的趋势。在本工作的详细研究中,使用了随机选择的点蚀缺陷的高分辨率3D扫描。结果表明,对表面缺陷形态的分析可以在一定程度上验证热/化学处理的质量。在受控(最佳)重复热处理条件下,残余奥氏体的马氏体相变可以显着提高小齿轮(齿轮)的耐久性。在分析的案例中,首选的治疗方法是低温治疗。本文根据所进行的微观和宏观研究得出了详细的结论。
    Today, there are many diagnostic methods and advanced measurement techniques enabling the correct diagnosis and assessment of the type and degree of wear of cogwheels (gears, pumps, etc.). The present study presents an analysis of the surface defects of a cogwheel of an oil pump prototype (3PW-BPF-24). The test object operated for a certain number of hours under controlled operating and environmental parameters. The damage to the surface layer was caused by fatigue phenomena and previous thermo-chemical treatment. On the basis of the significant percentage share (~30%) of residual austenite in the volume of the diffusion layer, a hypothetical conclusion was drawn about the suboptimal parameters of the thermo-chemical treatment process (in relation to the chemical composition of the analyzed pinion). A large number of research studies indicate that the significant presence of residual austenite causes a decrease in tooth surface hardness, the initiation of brittle cracks, a sharp decrease in fatigue strength, an increase in brittleness and a tendency to develop surface layer cracks during operation. High-resolution 3D scans of randomly selected pitting defects were used in the detailed study of the present work. It was indicated that the analysis of the morphology of surface defects allowed some degree of verification of the quality of the heat/chemical treatment. The martensitic transformation of residual austenite under controlled (optimum) repeated heat treatment conditions could significantly improve the durability of the pinion (cogwheel). In the case analyzed, the preferred treatment was the low-temperature treatment. The paper concludes with detailed conclusions based on the microscopic and macroscopic investigations carried out.
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  • 文章类型: Journal Article
    背景:斑秃(AA)是一种常见的非瘢痕性脱发,其特征是急性脱发。指甲参与,虽然并不总是存在,可发生于AA患者。在严重的AA和儿童中,指甲的变化更为频繁。方法:在没有时间限制的PubMed数据库上进行搜索后,对与AA指甲变化有关的文献进行了全面回顾,以确定常见的临床表现和相关因素,以帮助临床医生正确评估和管理这些营养不良。结果:AA的指甲变化包括点蚀,硬甲癣,白甲,红色Lunula,和杂项的变化,如纵向脊线和脆性钉子。指甲变化通常是无症状的,但是,然而,有时美容毁容,可能与生活质量下降和日常活动受损有关。结论:AA的指甲变化可能在脱发之前或之后发生,并且可以作为孤立的发现发生。诊断可能需要活检以明确识别。自发改善是可能的,特别是在儿童中,治疗并不总是必要的。进一步的研究是,然而,需要根据年龄和严重程度就治疗方法达成共识。
    Background: Alopecia areata (AA) is a common form of non-scarring alopecia characterized by acute hair loss. Nail involvement, though not always present, can occur in AA patients. Nail changes are more frequent in severe forms of AA and in children. Methods: Literature related to nail changes in AA was comprehensively reviewed after a search on the PubMed database without time restrictions in order to identify common clinical presentations and associated factors to aid clinicians with the correct evaluation and management of these dystrophies. Results: Nail changes in AA include pitting, trachyonychia, leukonychia, red lunula, and miscellaneous alterations such as longitudinal ridging and brittle nails. Nail changes are usually asymptomatic but, nevertheless, sometimes cosmetically disfiguring and can be associated with a reduced quality of life and impaired daily activities. Conclusions: Nail changes in AA may precede or follow hair loss and can occur as an isolated finding. Diagnosis may require a biopsy for definitive identification. Spontaneous improvement is possible, particularly in children, and treatment is not always necessary. Further research is, however, needed to establish a consensus on treatment approaches according to age and severity.
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  • 文章类型: Journal Article
    目的:下肢水肿是C3慢性静脉疾病的特征性表现。我们开发了一种新的临床和双工超声(DUS)方法,用于检测和定量腿部水肿,并前瞻性评估了其有效性。方法:使用改良的Suehiro分级量表,使用EdemaRulerTM和DUS评估了47例静脉患者(94条腿)的踝关节水肿。结果:对于改良的Suehiro等级,使用EdemaRulerTM的观察者间可靠性为0.985(p<.001)和0.883(p<.001)。与具有EdemarVCSS的DUS:(0.474;p<.001)相比,EdemaRulerTM与EdemarVCSS(0.842;p<.001)具有更强的显着相关性。CEAP分级C1和C2的水肿点蚀深度与C3、C4a相比有显著差异,C4cDUS分析仅在CEAP分类C2和C4a之间有显著差异。结论:EdmaRulerTM提供了一种高可靠性的下肢水肿定量测量方法,可以很容易地融入临床实践。虽然这两种方法都有很好的观察者间可靠性,EdemaRulerTM与EdemarVCSS有更强的相关性,与较高的CEAP评分(C3-4c)相比,较低的CEAP评分(C1-2)在凹陷深度上有显著差异.
    Objective: Lower extremity edema is characteristic of C3 chronic venous disease. We developed a new clinical and duplex ultrasound (DUS) methodology for the detection and quantification of leg edema and prospectively evaluated its usefulness. Methods: Forty-seven venous patients (94 legs) were evaluated for ankle edema using an Edema RulerTM and DUS using a modified Suehiro grading scale. Results: Interobserver reliability for the use of the Edema RulerTM was 0.985 (p < .001) and 0.883 (p < .001) for the Modified Suehiro Grade. The Edema RulerTM had stronger significant correlations with Edema rVCSS (0.842; p < .001) compared to DUS: (0.474;p < .001) with Edema rVCSS. There were significant differences between the edema pitting depth in CEAP classification of C1 and C2 compared to C3, C4a, and C4c. DUS analysis only had significant differences between CEAP classification C2 and C4a. Conclusions: The Edema RulerTM provides a quantitative measurement of lower extremity edema with high reliability which can be easily integrated into clinical practice. While both methods had good inter-observer reliability, the Edema RulerTM had stronger correlations to Edema rVCSS and showed significant differences in pitting depths between lower CEAP scores (C1-2) compared to higher CEAP scores (C3-4c).
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  • 文章类型: Journal Article
    本工作评估了Co含量对各种成分(2-32wt%Co)的Al-Co合金的微观结构和腐蚀性能的影响,通过焊剂辅助搅拌铸造制造。对热处理效果的初步调查(600°C,长达72h)还对Al-20wt%Co和Al-32wt%Co的微观结构和腐蚀行为进行了研究。Al-(2-10)wt%Co合金由均匀分散在Al基体中的针状Al9Co2颗粒组成。Al-20wt%Co和Al-32wt%Co合金还包含包裹在Al9Co2楔形物中的Al13Co4叶片。Al-20wt%Co和Al-32wt%Co的热处理导致Al13Co4的体积分数显着降低,硬度降低。具有高Co含量(10-32wt%Co)的Al-Co合金在3.5wt%NaCl中表现出对局部腐蚀的更大抵抗力,但与(0-5wt%的Co)合金相比,对一般腐蚀的抵抗力较低。热处理导致Al-Co合金的耐腐蚀性略有增加。分析了所生产合金的微观结构,并将其与腐蚀性能相关联。最后,制定了腐蚀机理。
    The present work evaluates the effect of Co content on the microstructure and corrosion performance of Al-Co alloys of various compositions (2-32 wt% Co), fabricated by flux-assisted stir casting. A preliminary investigation on the effect of heat treatment (600 °C, up to 72 h) on the microstructure and corrosion behavior of Al-20 wt% Co and Al-32 wt% Co was also conducted. The Al- (2-10) wt% Co alloys were composed of acicular Al9Co2 particles uniformly dispersed in an Al matrix. The Al-20 wt% Co and Al-32 wt% Co alloys additionally contained Al13Co4 blades enveloped in Al9Co2 wedges. Heat treatment of Al-20 wt% Co and Al-32 wt% Co led to a significant reduction in the volume fraction of Al13Co4 and a decrease in hardness. Al-Co alloys with high Co content (10-32 wt% Co) exhibited greater resistance to localized corrosion in 3.5 wt% NaCl, but lower resistance to general corrosion compared to the (0-5 wt% Co) alloys. Heat treatment led to a slight increase in the corrosion resistance of the Al-Co alloys. The microstructure of the produced alloys was analyzed and correlated with the corrosion performance. Finally, corrosion mechanisms were formulated.
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  • 文章类型: Journal Article
    下肢水肿是慢性静脉疾病和静脉功能不全的症状。然而,临床评价依赖于点蚀深度的定性评价,既不明确也不定量。我们创建了一种新颖的三维打印水肿尺,作为测量点蚀深度的定量方法。使用水肿尺评估了25例慢性静脉疾病患者(50条腿)的踝关节水肿。结果证明了单个(0.944,P<.001)和平均(0.971,P<.001)测量的优异的组内相关性。水肿标尺是一种非侵入性的,有用的,和客观工具,用于下肢水肿的临床测量。
    Lower extremity edema is a symptom of chronic venous disease and venous insufficiency. However, clinical evaluations rely on the qualitative evaluation of the pitting depth, which is neither well-defined nor quantitative. We created a novel three-dimensionally printed edema ruler as a quantitative method to measure pitting depth. Twenty-five patients (50 legs) with chronic venous disease were evaluated for ankle edema using the edema ruler. The results demonstrate excellent intraclass correlation for both single (0.944, P < .001) and average (0.971, P < .001) measurements. The edema ruler is a noninvasive, useful, and objective tool for the clinical measurement of lower extremity edema.
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  • 文章类型: Journal Article
    背景:犬外周水肿的不同病因的患病率和临床特征尚不清楚。
    目的:为了确定周围水肿的不同病因的患病率,描述不同病因的临床特征,并报告生存时间。
    方法:有外周水肿的五百二十七只狗。
    方法:回顾性病历回顾。病因学组之间临床变量的差异通过Kruskal-Wallis检验,事后成对Dunn检验和卡方检验与蒙特卡洛模拟评估。
    结果:狗周围性水肿最常见的病因是血管炎(n=193,37%),淋巴/静脉阻塞(LVO;114,22%),和低蛋白血症(94,18%)。右侧充血性心力衰竭(R-CHF)并不常见(25,5%)。水肿在377只(72%)狗中局部化,在142只(27%)狗中广泛化。与LVO或血管炎相比,低白蛋白血症更容易引起全身水肿(P<0.0001)。并发腹腔积液(155,29%)比胸膜积液(77,15%)或心包积液(12,2%)更常见。与LVO或血管炎相比,低白蛋白血症或R-CHF犬的腹腔和胸腔积液更常见(P<0.0001)。
    结论:水肿的分布,并发空洞积液,和临床病理数据可以帮助预测狗周围水肿的潜在病因。
    BACKGROUND: The prevalence and clinical characteristics of different etiologies of peripheral edema in dogs are unknown.
    OBJECTIVE: To determine the prevalence of different etiologies of peripheral edema, describe clinical characteristics that vary among etiologies, and report survival times.
    METHODS: Five hundred twenty-seven dogs with peripheral edema.
    METHODS: Retrospective medical record review. Differences in clinical variables among etiology groups were assessed by Kruskal-Wallis testing with post hoc pairwise Dunn\'s testing and Chi-square testing with Monte Carlo simulation.
    RESULTS: The most common etiologies of peripheral edema in dogs were vasculitis (n = 193, 37%), lymphatic/venous obstruction (LVO; 114, 22%), and hypoalbuminemia (94, 18%). Right-sided congestive heart failure (R-CHF) was uncommon (25, 5%). Edema was localized in 377 (72%) dogs and generalized in 142 (27%) dogs, and hypoalbuminemia was more likely to cause generalized edema compared to LVO or vasculitis (P < .0001). Concurrent abdominal effusion (155, 29%) was more common than pleural (77, 15%) or pericardial (12, 2%) effusion. Abdominal and pleural effusion occurred more commonly in dogs with hypoalbuminemia or R-CHF compared to LVO or vasculitis (P < .0001).
    CONCLUSIONS: Distribution of edema, concurrent cavitary effusions, and clinicopathological data can help predict the underlying etiology of peripheral edema in dogs.
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  • 文章类型: Journal Article
    碳氢化合物行业不断需要更好地了解不锈钢焊接冶金。尽管气体保护金属电弧焊(GMAW)是石化行业中最常用的焊接工艺之一,该方法的特征在于存在大量的变量来控制,以便获得尺寸可重复并满足功能要求的部件。特别是,腐蚀仍然是一种高度影响暴露材料性能的现象,焊接时必须特别注意。在这项研究中,通过在70°C腐蚀反应器中进行600h的加速试验,再现了石化工业的实际运行条件,暴露机器人GMAW样品没有缺陷与合适的几何形状。结果表明,即使双相不锈钢的特点是比其他不锈钢更耐腐蚀,在这些条件下,有可能识别微观结构损伤。详细地发现,腐蚀性能与焊接过程中的热输入密切相关,并且使用较高的热输入可以获得最佳的腐蚀性能。
    The hydrocarbon industry constantly requires a better understanding of stainless-steel welding metallurgy. Despite the fact that gas metal arc welding (GMAW) is one of the most commonly employed welding processes in the petrochemical industry, the process is characterized by the presence of a high number of variables to control in order to obtain components that are dimensionally repeatable and satisfy the functional requirements. In particular, corrosion is still a phenomenon that highly affects the performance of the exposed materials, and special attention must be paid when welding is applied. In this study, the real operating conditions of petrochemical industry were reproduced through an accelerated test in a corrosion reactor at 70 °C for 600 h, exposing robotic GMAW samples free of defects with suitable geometry. The results show that, even if duplex stainless steels are characterized for being more corrosion resistant than other stainless steels, under these conditions it was possible to identify microstructural damage. In detail was found that the corrosion properties were strongly related to the heat input during welding and that the best corrosion properties can be obtained with the higher heat input.
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  • 文章类型: Journal Article
    人工智能(AI)在临床中用于改善患者护理。虽然这些成功说明了人工智能的影响,很少有研究能改善临床结局.在这次审查中,我们专注于在腐蚀科学的非骨科领域实施的AI模型如何应用于骨科合金的研究。我们首先定义并介绍基本的AI概念和模型,以及生理相关的腐蚀损伤模式。然后,我们系统地回顾了腐蚀/人工智能文献。最后,我们确定了几个可以用来研究烦恼的人工智能模型,裂缝,钛和钴铬合金的点蚀。
    Artificial intelligence (AI) is used in the clinic to improve patient care. While the successes illustrate AI\'s impact, few studies have led to improved clinical outcomes. In this review, we focus on how AI models implemented in nonorthopedic fields of corrosion science may apply to the study of orthopedic alloys. We first define and introduce fundamental AI concepts and models, as well as physiologically relevant corrosion damage modes. We then systematically review the corrosion/AI literature. Finally, we identify several AI models that may be implemented to study fretting, crevice, and pitting corrosion of titanium and cobalt chrome alloys.
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  • 文章类型: Journal Article
    提出了一种大气双金属腐蚀的机理模型,该模型采用了简化的经验方法来解决局部腐蚀攻击。该模型是针对包含铝合金1050和不锈钢316L薄板的典型双金属样品建立的。开发了一种策略,可以根据测得的电流对模型进行校准,几何腐蚀侵蚀特性,和腐蚀产物。点蚀起始简化将所有凹坑设置为在较高金属附近的位置处形成,并且将所有凹坑处理为具有相同的形状和尺寸。该位置基于最高坑事件的位置和最深坑的平均坑属性。在受控RH下暴露5小时(85%,91%,和97%)和盐负荷(86μgNaCl/cm2),该模型被证明是有前途的:既用于分析局部双金属腐蚀化学,如pH值和腐蚀产物,并通过计算单个最大凹坑深度来有效评估点蚀损伤。参数研究表明,点蚀发作近似值在暴露开始时和RH低于91%时偏差最大。
    A mechanistic model of atmospheric bimetallic corrosion with a simplified empirical approach to the onset of localized corrosion attacks is presented. The model was built for a typical bimetallic sample containing aluminum alloy 1050 and stainless steel 316L sheets. A strategy was developed that allowed the model to be calibrated against the measured galvanic current, geometrical corrosion attack properties, and corrosion products. The pitting-onset simplification sets all pits to be formed at a position near the nobler metal and treated all pits as being of the same shape and size. The position was based on the location of the highest pitting events and the pit attributes on an average of the deepest pits. For 5 h exposure at controlled RH (85%, 91%, and 97%) and salt load (86 μg NaCl/cm2), the model was shown to be promising: both for analysis of local bimetallic corrosion chemistry, such as pH and corrosion products, and for efficient assessment of pitting damage by computing a single largest pit depth. Parametric studies indicated that the pitting-onset approximation deviated the most at the beginning of exposure and when RH was below 91%.
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  • 文章类型: Journal Article
    铝的钝化对其在电池中作为阳极的性能是有害的。在氯铝酸盐深共晶溶剂中浸泡天然氧化物覆盖的铝逐渐激活电极表面,这反映在一个不断降低的开路电位。通过分析3至7nm厚的天然氧化物层后,用二次中性质谱浸泡时间增加,研究了潜在的过程。X射线光电子能谱,和透射电子显微镜中的能量色散光谱。它们一致地显示出电解质物质渗透到与逐渐膨胀相关的层中。在开路电位下长时间浸泡后,在电极表面的扫描电子显微镜图像中发现了一系列外来金属的局部沉积物。点蚀是由电解质中存在的痕量金属离子杂质引起的,并且在电池单元的放电/充电循环期间导致高度不均匀的电流密度分布,如铝的局部沉积所示。已通过电化学阻抗谱监测了在开路电位下浸泡的过程,并且可以通过拟合点蚀的等效电路模型来分析。
    The passivity of aluminum is detrimental to its performance as an anode in batteries. Soaking of native oxide-covered aluminum in a chloroaluminate deep eutectic solvent gradually activates the electrode surface, which is reflected in a continuously decreasing open circuit potential. The underlying processes were studied by analyzing the 3 to 7 nm thick layer of native oxide after increasing periods of soaking with secondary neutral mass spectrometry, X-ray photoelectron spectroscopy, and energy-dispersive spectroscopy in a transmission electron microscope. They consistently show permeation of electrolyte species into the layer associated with gradual swelling. After extended periods of soaking at open circuit potentials, local deposits of a range of foreign metals have been found in scanning electron microscopy images of the electrode surface. The pitting corrosion is caused by trace metal ion impurities present in the electrolyte and results in highly nonuniform current density distribution during discharge/charge cycling of battery cells as shown by local deposits of aluminum. The processes during soaking at open circuit potentials have been monitored by electrochemical impedance spectroscopy and could be analyzed by fitting an equivalent circuit model for pitting corrosion.
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