Volumen 28 (2022): Heft 2 (June 2022)

A number of modern surface processing methods use an energy flux. The examples include electro-spark deposition (ESD) and laser beam processing (LBP). The work concerns the study of Cu-Mo coatings deposited on C45 carbon steel, which were then eroded with a laser beam. The analysis included the analysis of the microstructure, measurements of macrogeometry and microhardness, corrosion resistance tests of selected areas after laser treatment. The coatings were applied with ELFA-541 and subjected to Nd:YAG laser treatment with variable laser parameters. The problem presented in the work can be used to extend the knowledge of the areas of application of ESD coatings, especially in sliding friction pairs.

The temperature-stress state of the concrete facade wall with a window opening, which is the external enclosing structure of the room with a steel heating device, was investigated by the method of numerical modeling. Estimated studies were performed for winter period when the heating system of the building is functioning. According to the results of solving the system of equations of thermal stress and equation of thermal conductivity, the temperature distribution over the wall volume and distribution of normal and tangential stresses were determined. Areas of the wall where these stresses are maximum were identified. The research was performed for cases of both, absence and presence of a heat-insulating layer on the outer surface of the facade wall. From comparison of the results obtained for these two options, it follows that the external thermal insulation coating not only helps to reduce dissipative heat loss through the facade wall, but also reduces the absolute values of stresses in the concrete wall arising resulting from temperature deformations. In some cases, the sign of stresses changes from stretching (wall without external insulation) to compressive (wall with insulation).

The paper investigates the modelling and optimization of the notch-repaired/friction stir stitched AISI 201 stainless steel welds via the use of a non-consumable tool-based repair process. The repair process employs a sequential hopping-stitching approach. This approach involves the application of two intercepted and completely overlapped plunging actions of a probe-less titanium carbide tool to create an effective refilling and repair of the notched zone. Box-Behnken design (BBD) was employed for the experimental planning, modelling, and optimization of the notch-repair process. Tool rotational speed, penetration depth and dwell time of the tool were the studied process parameters while tensile strength was the response variable. A quadratic model was identified as the best model for the notch-repaired welds based on the combination of a low sequential P-value of 0.008216, a high lack of fit P-value of 0.931366, and a close to unity adjusted and predicted R-square values. The process parameter and their interaction effects on the tensile strength of the repaired notch were identified via the ANOVA analysis. Plunge depth (main effect) and interaction effect of tool rotational speed and dwell time had significant influences on the notch-repair process and the resultant tensile strength of the AISI 201 stainless steel. The visual representations of these effects were shown through the 2D elliptical contour and 3D response surface plots. The optimized process parameters were identified as 1215.9795 rpm, 0.40262212 mm, and 5.98706376 s while the resultant notch-repaired joint yielded a tensile strength of 886 MPa, which is close to the predicted value.

This work presents the results of a numerical study of the working processes of burning lignite in a vortex furnace with swirling countercurrent flows. The results of computer simulation of the processes of burning lignite with a moisture content of 30%, an ash content of 20% and 35% and a higher calorific value of Qрв = 13.9 MJ/kg and 9.7 MJ/kg, respectively are given. The fields of temperature distribution, gas velocity and particle trajectory in the volume and at the outlet of the furnace are determined. The values of the swirling flow velocity near the exit from the furnace reach 150-170 m/s. Mechanical underburning is 3.7% and 9.4% depending on the ash content. The results of a numerical study have showed that the diameter of lignite particles affects their combustion process: coke particles with an initial diameter from 25 microns to 250 microns burn out by 96%. The furnace provides a complete combustion of pulverized coal particles - 99.8% and of volatiles - 100% at volumetric heat stress in the 2500 kW/m³ furnace. The afterburning of fuel particles containing carbon is ensured by their circulation

Accurate forecasting of municipal solid waste (MSW) generation is important for the planning, operation and optimization of municipal waste management system. However, it’s not easy task due to dynamic changes in waste volume, its composition or unpredictable factors. Initially, mainly conventional and descriptive statistical models of waste generation forecasting with demographic and socioeconomic factors were used. Methods based on machine learning or artificial intelligence have been widely used in municipal waste projection for several years. This study investigates the trend of municipal waste accumulation rate and its relation to personal consumption expenditures based on the yearly data achieved from Local Data Bank (LDB) driven by Polish Statistical Office. The effect of personal consumption expenditures on the municipal waste accumulation rate was analysed by using the vector autoregressive model (VAR). The results showed that such method can be successfully used for this purpose with an approximate level of 2.3% Root Mean Square Error (RMSE).

The objective of this study is to optimize the fabrication factors of a consumer-grade fused filament fabrication (FFF) system. The input factors were nozzle temperature, bed temperature, printing speed, and layer thickness. The optimization aims to minimize average surface roughness (Ra) indicating the surface quality of benchmarks. In this study, Ra was measured at two positions, the bottom and top surface of benchmarks. For the fabrication, the material used was the Polylactic acid (PLA) filament. A response surface method (RSM), central composite design (CCD), was utilized to carry out the optimization. The analysis of variance (ANOVA) was calculated to explore the significant factors, interactions, quadratic effect, and lack of fit, while the regression analysis was performed to determine the prediction equation of Ra. The model adequacy checking was conducted to check whether the residual assumption still held. The total number of thirty benchmarks was fabricated and measured using a surface roughness tester. For the bottom surface, the analysis results indicated that there was the main effect from only one factor, printing speed. However, for the top surface, the ANOVA signified an interaction between the printing speed and layer thickness. The optimal setting of these factors was also recommended, while the empirical models of Ra at both surface positions were also presented. Finally, an extra benchmark was fabricated to validate the empirical model.

This paper presents a framework of contemporary quality costs concept contributing to a more sustainable society regarding an integrated view of quality costs in all phases of the product life cycle (engineering, production, use, and end-of-life) by all stakeholders in the supply chain. The development of this framework is viewed through the complementarity of the sustainability dimensions and the circular economy concept understood as a waste management concept, which represents a solid basis for the development of a novel approach to understanding quality costs which, in turn, reflects the sustainable quality concept. By providing sustainable criteria (economic, environmental, and social) as an integral part of the quality costs concept, this framework will improve the sustainability performance in the early phases of product design, increase the added value of the products and the duration of the added value, and strengthen the responsibility of all stakeholders beyond the limits of their organizational processes. This will inevitably lead to changes to the quality cost structure, dominated by new quality costs elements which reflect sustainability. This research demonstrates the findings that should support the setting the theoretic assumptions for the development of a sustainable quality cost generic model.

This paperwork is focused on the quality of AlSi6Cu4 casting with different wall thicknesses cast into the metal mold. Investigated are structural changes (the morphology, size, and distribution of structural components). The quantitative analysis is used to numerically evaluate the size and area fraction of structural parameters (α-phase, eutectic Si, intermetallic phases) between delivered experimental material and cast with different wall thicknesses. Additionally, the Brinell hardness is performed to obtain the mechanical property benefits of the thin-walled alloys. This research leads to the conclusion, that the AlSi6Cu4 alloy from metal mold has finer structural components, especially in small wall thicknesses, and thus has better mechanical properties (Brinell hardness). These secondary Al-castings have a high potential for use in the automotive industry, due to the thin thicknesses and thus lightweight of the construction.

The article describes a student project of installing a micropower generation system utilizing energy from the water drained from underground coalmines. The paper contains a description of the site which is a manmade phenomenon from the anthracite mining era. The project described in the article was completed as part of the project-based learning curriculum. Students had the opportunity to work on a team and apply theoretical knowledge learned in individual courses as part of the engineering curriculum. The article also focuses on the calculation of the potential power capacity to a proposed hydropower generation system. The proposed micro-hydro system is harvesting the potential and kinetic energy of the water discharged from the water-draining tunnel. A commercially available micro-hydro turbine combined with an electric power generator was adapted for this purpose. The article also includes an analysis of the profitability of the project and the time of return on investment. The calculations are based on the current price of electricity (2021), depreciation schedule and present tax incentives (2021) to generate electricity from renewable sources. The article also includes some lessons learned from the project as well as the recommendations for future projects.

In the paper the author has attempted to achieve two convergent objectives: cognitive and empirical ones. The cognitive goal constituted an analysis of the definitions of virtual organi-sations and their adaptation while defining Virtual Power Plants (VPPs). When discussing the discourse in the area of virtual organisations, the author has attempted to justify the fact that the terminology pertaining to virtual organisations should constitute the foundations for defining Virtual Power Plants. With such an assumption, a vital importance has been assigned to co-sharing of “soft” resources – key competencies, and also organisational (managerial) integration. In the context of the adopted definitions, the distributed structure of virtual power plant has been em-bedded into four layers of Smart Grid: Customer Technology, Operational Technology, Smart Metering, Energy Management System. A measurable value of the conducted discourse has been aggregation of management functions of VPP, carried out in the four-layer structure of Smart Grid. In turn, the empirical objective was to determine and distinguish, based on the conducted expert research, the factors that determine the development of small-scale energy sector, including re-newable energy sources and prosumer installations – simultaneously determining the inclination of distributed electricity producers to mutual integration in the structures of virtual power plants. Assuming, in accordance with the definitions and discourse included in the first part of the paper, that the determined factors, among others, creating virtual power plants are not only of techno-logical nature, the author has developed four portfolios of these factors. They include the following ones: technological, economic (including micro- and macro-economic), environmental, and social. The experts participating in the research could select 5 factors from each of the developed portfolio which in their opinion determined the inclination of distributed electricity producers to integrate their sources in the structures of virtual power plants. A measurable value of the empirical part has been aggregating the determinants generated and distinguished in the research process.

The rapid development of the manufacturing sector has been causing industrial effluents pollution. The practice of environmental regulation in the emerging economy focused on the externalities impact of industrialization. In conjunction with the issue, this study examines the effect of formal and informal regulation on the industrial effluent act and the firm compliance behavior in Malaysia. This quantitative study uses a survey questionnaire (structured) and involved 42 factories of three industries, namely food and beverages, textiles, and paper in Penang, Kedah, and Perlis. The data were analyzed using non-parametric tests: The Chi-Square, Mann-Whitney, and Spearman’s Rho. This study uses the firm behavior theory as the framework, and our non-parametric analyses showed that the traditional enforcement and fined probability could significantly affect compliance levels. We also find the market, consumer, competitor, and investor pressure positively influence firm compliance. The empirical results suggest effective enforcement of environmental regulation and the role of non-regulation must be empowered as a support mechanism for pollution control.

The revitalization of mining dumps in the Silesian agglomeration is a very difficult and complex problem. It has a substantial impact on the concepts of sustainable urban development. Other than the key areas including people, the environment and the economy, revitalization also refers to spatial management, and thus to a significant improvement in the functioning conditions of the local cities’ communities. The article describes an algorithm assessing the possibilities of revitalizing a mining dump by one of the Polska Grupa Górnicza’s mines. With legal status and location taken into account, several potential scenarios had been proposed, out of which one was chosen based on the adopted criteria. The chosen scenario had been subjected to further assessment using analyses such as SWOT/TOWS, FMEA, and QFD. The analyses had been carried out in order to acquire more effective and meaningful assessments, having taken social and economic aspects into consideration. In effect of the carried out analysis a recreational scenario was proposed. The adopted solution shows that the mine can continue its work in accordance with the principle of sustainable development as well as apply the concept of corporate social responsibility.