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Abstract

A number of PCB defects, though having passed successfully the defect identification procedure, can potentially grow into critical defects under the influence of various external and (or) internal influences. The complex nature of the development of defects leading to PCB failures demands developing and updating the data measuring systems not only for detection but also for the prediction of future development of PCB defects considering the external influences. To solve this problem, it is necessary to analyse the models of defect development, which will allow predicting the defect growth and working out the mathematical models for their studies.

The study uses the methods of system analysis, theory of mathematical and imitation modelling, analysis of technological systems. The article presents four models for determining the theoretical stress concentration factor for several types of common defects, considering the strength loss of PCB elements. For each model the evaluation of parameters determining its quality is also given. The formulas are given that link the geometry of defects and the stress concentration factor, corresponding to four types of defects. These formulas are necessary for determining the number of cycles and time to failure, fatigue strength coefficient.

The chosen models for determining the values of the stress concentration factor can be used as a database for identifying PCB defects. The proposed models are used for software implementation of the optical image inspection systems.

Abstract

In the present work the comparison of the effect of traditional, pulse and stress annealing is made by monitoring the important mechanical and magnetic properties of FINEMET type amorphous precursor alloy. The magnetic properties were determined from the shape of magnetization curve (coercive force, anisotropy) during various heat treatments and the mechanical properties were measured using brittleness test. The traditional heat treatments were performed in resistance furnace and the magnetic measurements were performed in astatic magnetometer. The pulse and stress annealing (as well as their combinations) were carried out inside in the magnetometer. The temperature of pulse heat treatments is regulated with the length of current pulse flowing through the sample. After each pulses the magnetization curves were measured in-situ, in the magnetometer.

Abstract

Hyperkeratotic lesions result from continuous mechanical action on the skin forming a callus or a corn. The accumulation of horny layers will increase pressure, creating a vicious cycle. We present a new approach based on relieving pressure or friction, strictly based on the results of pedography (pedobarography).

Abstract

In this article the engine piston Renault Premium DXi11 430 460 EEV has been analysed using the Finite Element Method. Analysis consider as well heat transfer phenomenon as the thermal and mechanical strains of the piston. Simulations were performed for the point of engine maximum power. Piston material was assumed to be 40HM (1.7225) steel and its properties are delivered basing on available scientific papers. The simulation assumed mean values of heat transfer coefficient, reference temperature and cycle pressure based on engine data, maximum power engine work simulation in AVL Boost software and literature. Part of boundary condition (e.g. cylinder wall temperature) was assumed basing on authors’ engineering intuition and experience. The resulting temperature distribution in the piston was implemented for geometrically nonlinear mechanical FEM analysis. Both the analysis of thermal stresses and stresses of the hot piston in the top dead centre were performed.

that was performed by an expert endoscopy consultant. One possible explanation of this is the variation in endoscopic appearances of GAVE over time, possibly related to blood flow, hemoglobin concentration, or synchronous other gastric pathology such as gastritis. CE can be regarded as “physiologic” endoscopy, without the need for air insufflation and subsequent compression of the gastric vasculature, and this may make lesions such as GAVE more prominent on CE. The pathogenesis of GAVE is still obscure, and many hypotheses such as mechanical stress, hemodynamic

References [1] Brnic, J., Turkalj, G., Canadija, M., Niu, J., Experimental determination and prediction of the mechanical properties of steel 1.7225 , Materials Science & Engineering, Vol. 600, April 2014. [2] Hohenberg, G., Experimentelle Erfassung der Wandwaerme von Kolbenmotoren , Habilitationsschrift TU-Graz, 1980. [3] Kaliszewski, M., Mazuro P., Analysis of thermal and mechanical stresses of Renault Premium DXi11 460 EEV piston (preprint). [4] Renault Trucks SAS, Renault Trucks Deliver: Renault Premium Long Distance , 08/2009. [5] Wiśniewski, T. S

films prepared by sol-gel method. The formation of the wrinkled structure increased the roughness of the ZnO thin films, which deteriorated their electrical and optical properties. Maiti et al. [ 21 ] indicated that the formation of wrinkled surface was due to the presence of monoethanolamine in the precursor. Hou et al. [ 22 ] suggested that the formation of wrinkled structure was related to the release of mechanical stress, which was generated during the baking process. By adjusting the preheating conditions in the spin-coating process, the formation of wrinkled

2001;6:A15. 38. Ponchiardi C, Fall B, Scott R, Uhrich S, Mauer M, Whitley C, et al. Podocyturia correlates with proteinuria in patients with Fabry disease (FD) and is a potential biomarker of Fabry nephropathy. Mol Genet Metab 2013;108:S76-7. 39. Ryu M, Mulay S, Misoge N, Gross O, Anders H. Tumor necrosis factor-β drives Alport glomerulosclerosis in mice by promoting podocyte apoptosis. J Pathol 2012;226:120-31. 40. Endlich N, Kress K, Reiser J, Uttenweiler D, Kriz W, Mundel P, et al. Podocytes respond to mechanical stress in vitro. J Am Soc Nephrol 2001

Abstract

The article deals with the use of acoustic emission to identify the formation of cracks during the mechanical loading in the corrosive attacked weldment S235JR+N. The experiment includes the methodology for continual record of emissive signals, data analysis and monitoring of material response to monitor mechanical stress effect in real time. There is possibility to observe response of corrosive degraded samples in real time during mechanical stress through the suitably designed methodology of detection, process and analysing of acoustic emission signals. It is possible to gain new information about processes rising inside the material by this way of data measurement. The signals of acoustic emission can be used as the way of identification for the micro cracks rising in the inner and also external structure of effortful materials.

Abstract

An overview of protection mechanisms of organic coatings for metallic constructions and products is given. The barrier effect of coatings and protection in local defects are discussed. Basic degradation mechanisms of organic coatings such as anodic and cathodic delamination in vicinity of defects, osmotic and cathodic blistering, mechanical stress assisted blistering, loss of adhesion and chalking are described. Appropriate laboratory tests are proposed for each degradation mode.