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Abstract

The article presents sources of production knowledge and thoroughly describes its identification which on the construction of decision trees, and on the construction of knowledge bases for production processes. The problems that arise during the technical preparation of production are briefly characterized and the advanced algorithm with which decision trees can be built is described in detail. A decision tree was built based on real data from the manufacturing company. Decision trees are presented as a method of knowledge representation.

Abstract

Internal logistics is a key element of a production process as it specifies product quality, timeliness and value of orders. The purpose of the research was to determine the amount of non-compliance in the selected production process caused by internal logistics operations. The analysis covers both the quantity and type of non-compliance as well as the cost of non-compliance. One of the basic quality management tools was used in the research - Parteo-Lorenz analysis. An attempt was made to identify potential causes of non-compliance. The significant impact of non-compliance arising in internal logistics operations in production costs was pointed out.

Abstract

Bisphenol A (BPA) is an industrial chemical used as an additive in conventional point-of-sale thermal paper receipts, in the production of many polycarbonate plastics, and epoxy resins lignin for food. BPA is xenoestrogen, a foreign compound that is not naturally produced in living organisms, but which acts similarly to natural 17-ß estradiol (natural estrogen). Due to its weak estrogenic activities, BPA exposure may influence multiple endocrine-related pathway, and is associated with prostate and breast cancer, neurobehavioral deficits, heart disease, and obesity. Furthermore, BPA may act as a DNA methylation agent and cause altered gene expression in the brain. Human exposure to bisphenol A is a matter of controversy. This review shows a potential risks in workplace resulting from contact with bisphenol A. The work presents the contribution of BPA exposure levels via dermal contact and the relationship between BPA exposure level and oxidative DNA damage.

Abstract

High strength low alloy (HSLA) steels are a new generation of plain carbon steels with significantly improved mechanical properties while maintaining good weldability with common commercial techniques. Residual stress and microstructural analysis of welded HSLA Strenx 700 MC was carried out in this research. Results have shown that the welding process causes significant grain coarsening in the heat affected zone. The microstructural changes are also accompanied with creation of tensile residual stress field in the weld metal and heat affected zone, reaching up-to depth of 4 mm. Tensile residual stresses are well known for acceleration of fatigue crack initiation and together with coarse grains can lead to significant decrease of the fatigue properties of the welded structure.

Abstract

Remarkable place of reinforced concrete structures in construction field has been noted in wide number of recent researches. Subsequently, their degradation due to aggressive environment has become the topical problem nowadays. Therefore, the formulation of reliable technique for corroded element strength decrement is of great importance, and could be achieved only with the use of complex experimental and theoretical analysis. In this article an attempt is made to propose the mathematical approach to corrosive process modelling, taking into consideration the specifics of its development. According to thorough literature review on existing studies, main specifics of the process were indicated for further suppositions and assumptions formulation. Accordingly, the complex theoretical investigation with corresponding mathematical computations was conducted and results of analytical modelling were discussed. As the initial data for analytical modelling results of previously conducted experiments were used. Analysis of the obtained results shows rather high correspondence with the real conditions of structural element exploitation, taking into consideration material anisotropy and complexity of the corroded zone spread along the rebar cross-section. Proposed methodology for limit force decrease evaluation in general demonstrates reliable results and could be used for further evaluation of corrosion impacts on reinforced concrete elements bearing capacity.

Abstract

The practical implementation of hazard analysis and critical control point (HACCP) and in particular the definition of the critical control points (CCPs) in the food industry is usually a complex structured task. This is particularly the case of food enterprise, where quality/safety manager ability, knowledge of the production processes and ‘‘sensitiveness’’ is usually the discriminate for the proper identification and prioritization of risks. The same applies for the definition of causes which may lead to food safety hazards. This paper addresses the issues of how quality/safety managers can objectively and automatically implement the HACCP principles of hazard analysis in the application of HACCP, which is the identification of risk priorities and of the related CCPs. The proposed methodology combines decision tree analysis approach for the analytical decomposition of the relevant steps in the manufacturing process of ice cream.

Abstract

The aim of the following research it to provide assumptions for creating workflow efficiency model that can be implemented in repeatable production workstations. One of the main components of this model are human activities and their interactions with other elements of working environment: human and artefacts. Recognition of patterns of human behaviours within working processes gives the opportunity to find critical points that influence workflow efficiency.

The subject of research is a working process existing in meat producing plant. The main method used for recognizing human activity patterns was observation and qualitative and quantitative assessments of operational activities based on video registration. Particularly, human activities were analyzed under ergonomics criteria in order to proof dependencies between process efficiency and specific ergonomic factors forming working conditions at meat plant.

Abstract

Thermal fracture characteristics – the thermal energy release rate and thermal stress intensity factor of a semi-infinite crack at an interface between the two elastic isotropic materials, subjected to the temperature variations, are considered in this paper. Those characteristics are determined based on application of the linear elastic fracture mechanics (LEFM) concept. Expressions for obtained theoretical solutions are compared to solutions from literature and they are found to be more concise. Influence of the materials change on these two thermal fracture properties were observed, as well as the influence of the thickness ratio of the two layers constituting the interface.

Abstract

Designing and proper implementation of effective processes and providing the customer with high quality products undoubtedly determines the stable position on the market. The aim of the study was to analyse the cost and value of the technological process of doors in the context of creating added value and to identify unnecessary processes (not creating added value) in relation to which appropriate corrective actions could contribute to their elimination. Thanks to the application of remedial measures, consistent with the lean manufacturing concept, the study eliminated, among other things, operations related to unnecessary transport and storage of products, which resulted in both the reduction of time and costs of process implementation.

Abstract

Making a complex analysis of the problem in order to identify the root of its occurrence, is the process burdened with the risk of uncertainty. This risk is in case of the quality analysis, in which the choice and making a decision is not confirmed by reliable information (number). This risk is in case of the quality analysis, in which the choice and making a decision is not confirmed by reliable information (number). But these techniques do not include the risk of uncertainty, so their sequence should be expanded about the appropriate method, to take this into account. It was considered beneficial to demonstrate that this method is the Fuzzy Analytic Hierarchy Process method (FAHP). The aim of the study to implement the FAHP method in the sequence of traditional quality management techniques (Ishikawa diagram and 5Why method) and proposition new, not practiced yet the method to complex analysis of the problem and identify the root of its root cause. The subject of the study was the furniture front, on which the incompatibility was identified (shortened foil). From the categories to which the potential causes of the inadequate foil were assigned, by using the Ishikawa diagram and the FAHP method in an integrated manner, were defined the most important categories (method and machine) in a precise (numerical) way. Next, using the same tools, the relationship between the potential causes was analysed and selected the main causes of the problem. Then, by using the 5Why method the root of the problem was defined (lack of the new machine and failure to comply with labor standards). The obtained results could differ depending on the subjectivity, however, the method itself proved to be effective and can be used to solve other types of the problem.