rss_2.0Materials Sciences FeedSciendo RSS Feed for Materials Sciences Sciences Feed Tool Shoulder Design for the Analogue Modelling of Bobbin Friction Stir Weld Joint Quality<abstract><title style='display:none'>Abstract</title><p>A variety of tool shoulder designs comprising three families i.e. blade, spiral and circular shaped scrolls, were produced to improve the material flow and restrictions to avoid the tunnel void. The bobbin tools were manufactured by 3D printing additive manufacturing technology using solid filament. The butt weld joint was produced by each tool using plasticine as the workpiece material. The apparent surface features and bi-colour cross-sections provided a physical flow comparison among the shoulder designs. For the bobbin friction stir welding (BFSW), the tool shoulder with a three-spiral design produced the most stability with the best combination of the flow patterns on surface and cross-sections. The circular family tools showed a suitable intermixing on the surface pattern, while the blade scrolls showed better flow features within the cross-sections. The flow-driven effect of the shoulder features of the bobbin-tool design (inscribed grooves) was replicated by the 3D-printed tools and the analogue modelling of the weld samples. Similar flow patterns were achieved by dissimilar aluminium-copper weld, validating the accuracy of the analogue plasticine for the flow visualization of the bobbin friction stir welding.</p></abstract>ARTICLE2021-03-30T00:00:00.000+00:00Properties of Flame Spraying Coatings Reinforced with Particles of Carbon Nanotubes<abstract><title style='display:none'>Abstract</title><p>The article presents the results of the preliminary research of tribological properties of flame sprayed nickel and aluminum coatings reinforced with carbon nanotubes made on the structural steel S235J0 substrate. The carbon material – carbon nanotubes Nanocyl NC 7000 (0.5 wt.% and 1 wt.%) was used for structural reinforcement. The properties evaluation was made by the use of optical microscopy, scanning electron microscopy, Raman spectroscopy, microhardness measurements, and by means of abrasion and erosion resistance laboratory tests. The obtained results were compared with pure nickel powder coatings 2N5 (Ni 99.5%) and with pure aluminum powder coatings (EN AW 1000 series). It was proved that the flame spraying of nickel and aluminum coatings reinforced with particles carbonaceous material can be an effective alternative for other more advanced surfacing technology. The preliminary test results will be successively extended by further experiments to contribute in the near future to develop innovative technologies, that can be implemented in the aviation industry and the automotive. The presented research is a continuation of the work previously published.</p></abstract>ARTICLE2021-03-30T00:00:00.000+00:00Regularities of Adsorption of Α-Oxypropionic Acid By Natural Zeolite<abstract><title style='display:none'>Abstract</title><p>Wastewaters from dairy processing factories contaminated with α-oxypropionic acid were monitored. Theoretical analysis of industrial wastewater treatment methods on zeolites of Sokyrnytsia deposit was carried out. The process of sorption of α-oxypropionic (α-oxypropionic) acid by natural zeolite of Sokyrnytsia deposit was considered. It was established that the most economically advantageous and safe is the method of adsorption using a natural sorbent - zeolite, which provides the lowest concentration of contaminants in treated wastewaters from dairies. An assessment of their number, localization features and measures of toxicological impact on the environment was done. The existing theoretical apparatus of description of adsorption processes was analyzed. The sorption properties of natural zeolite (clinoptilolite of Sokyrnytsia deposit) and activated carbon to α-oxypropionic acid were tested. Equilibrium values of adsorption capacity were calculated and corresponding isotherms at a temperature of 20 ° С were constructed. The porosity of the sorbent and its influence on the sorption properties were studied by the methods of physicochemical analysis. Infrared spectroscopic and electron microscopic studies confirmed the presence of the process of sorption by the surface of the internal pores of the zeolite of α-oxypropionic acid molecules. Experimental studies have confirmed the possibility of using natural zeolite for wastewater treatment of dairy factories. It was experimentally confirmed by physicochemical methods of analysis (electron microscopy, IR spectroscopy, microprobe analysis, mercury porometry) and was established that the process takes place both by the mechanism of ion exchange and physical adsorption. The content of carbon radicals in the zeolite matrix after the sorption process was confirmed by X-ray spectral microanalysis. The ability of zeolite to adsorb organic carboxylic acid radicals was confirmed by the results of IR spectroscopic studies. On the IR spectra there are strips of deformation and valence oscillations of the groups of the crystal lattice of the zeolite Si-O, Si-O-SiOH: 452, 990–1210, 1638, 3368 cm<sup>−1</sup>. The oscillation spectra of free OH groups in the region of 2600 cm<sup>−1</sup> were revealed.</p></abstract>ARTICLE2021-03-30T00:00:00.000+00:00Effect of Trapezoidal Shapes on the Thermal Buckling Behaviour of Perforated Composite Plates<abstract><title style='display:none'>Abstract</title><p>Thermal buckling study on the symmetric laminated composite trapezoidal plate with a circular cutout subjected to a uniform increase in temperature for various boundary conditions is explored in this paper. In a mathematical model, the first-order shear deformation principle is employed in accordance with the variational energy system. For acquiring the thermal buckling temperature, a nine-node heterosis plate relation has been used in the finite element formulation. By correlating the present findings with accessible literature, the effectiveness of the present formulation is verified. The impact of different parameters, such as trapezoidal shape, cutout size, ply-orientation, plate edge conditions and plate width to thickness ratio have been considered to study the effect of each parameters on the buckling characteristics of plate under various temperatures. It is observed from the study that each parametric investigation significantly affect the thermal buckling behaviour of trapezoidal plates.</p></abstract>ARTICLE2021-03-30T00:00:00.000+00:00Advances in Materials Science Editorial on the Journal’s 20 Anniversary Analysis of the Influence of the Flux-Cored Wire Chemical Composition on the Electrical Parameters and Quality in the Underwater Wet Cutting<abstract><title style='display:none'>Abstract</title><p>The paper presents research in the field of underwater wet cutting with the use of flux-cored wires in order to improve the quality and performance. The research has resulted into the development of gas and slag systems for flux-cored wires and determination of, optimal parameters for cutting stability and quality. The underwater wet cutting mechanism is a cyclical process with the formation of periodic keyholes in metal, and it consists of operating and idle cycles. Efficiency of the cutting process can be determined by analyzing cycle times, welding current, voltage, power and a number of short circuits. To assess the stability and efficiency of the underwater wet cutting process, the authors have developed the method for analyzing oscillograms to calculate the probability density of current, voltage and power. To determine the quality of cutting, the authors have provided a criterion based on the ratio of the voltage probability density in the idle and operating cycles.</p></abstract>ARTICLE2021-03-30T00:00:00.000+00:00The influence of water price and the number of residents on the economic efficiency of water recovery from grey water<abstract> <title style='display:none'>Abstract</title> <p>This article presents the results of an analysis of the economic viability of using an installation for the treatment of grey water. Economic indicators in the form of simple payback time (SPBT) and net present value (NPV) were used in the analysis. The use of a dual water supply system should theoretically enable the reduction of the costs of both water supply and sewage disposal, ensuring investment profitability. The article presents the impact of the number of residents as well as the impact of water and sewage on the profitability of using example water-recovery systems. It was found that both factors have a huge impact on the result of the economic analysis. For a small number of residents and at a low price of water supply and sewage disposal, it is not profitable to invest in a water-recovery system. This is due to the high price of purification devices.</p> </abstract>ARTICLE2021-02-05T00:00:00.000+00:00A suitability assessment using an instrumented impact test of the use of selected structural steel grades on the basis of their changes in response to exposure to fire<abstract> <title style='display:none'>Abstract</title> <p>In this article, changes occurring in structural steel after exposure to fire are described and discussed. The steel structure before and after fire determines its susceptibility to brittle cracking. The individual phases of cracking are described and interpreted on the basis of a load-displacement graph, directly obtained from the Charpy impact test. The relationship between the intensity of individual fracture energies and the type and appearance of the sample fractures are demonstrated. The program of planned Charpy impact tests and expected hazards after the exposure to fire of selected steel grades are presented. Standard simplified load-displacement graphs are assigned to the steel transition curve. The course of various cracking mechanisms occurring in the case of brittle fractures and plastic fractures are discussed. The aim of this article is to evaluate the possibility of the assessment of structural steel after a fire based on results obtained during the Charpy impact test.</p> </abstract>ARTICLE2021-04-27T00:00:00.000+00:00Small Historical Centres: an opportunity for the “smart” revitalization of Inner Areas in the Post (post) COVID Era<abstract> <title style='display:none'>Abstract</title> <p>The Pandemic is forcing everyone to become aware of the need for a change in the cultural and socio-economic paradigms of recent decades.</p> <p>During the twentieth century, on the one hand, entire populations concentrated in urban areas with ever higher population densities, at the same time giving rise to the phenomenon of “urban sprawl” or “suburbanization”.</p> <p>On the other hand, entire territories have been abandoned (the so-called “inner areas”).</p> <p>Now, we can define territorial rebalancing strategies based precisely on the reactivation of “inner areas”. Strategies that, in the Post (post) COVID era will have to be not only resilient, but anti-fragile. And the key is precisely in the future of the smaller historical centres.</p> <p>This article aims to review the strengths and weaknesses of small historic centres, outlining possible scenarios for their “smart” revitalization and for a true sustainable and inclusive development.</p> </abstract>ARTICLE2021-04-18T00:00:00.000+00:00Analysis of the possibility of employing 3D printing technology in crisis situations<abstract> <title style='display:none'>Abstract</title> <p>Events related to climate change and the increase in the occurrence of natural disasters, as well as the increasing incidence of new diseases, have all caused the prominence of regional security and crisis management around the world to rise. Three-dimensional printing, which has seen noteworthy developed in recent years, both in terms of print parameters, and the magnitude of the production potential, may prove helpful in this matter. Enormous opportunities have arisen which, if properly directed, can save human life and preserve health in crisis situations, when traditional supply chains could be disrupted or even prevented. The use of additive technologies, however, has its limitations and in order to be able to take full advantage of the opportunities they offer, a legitimate functional system should be created and embedded within proper structures to support crisis management. This paper presents the advantages and disadvantages of using 3D printers and the possibility of their implementation as part of the current crisis-response systems. The article proposes a model for incorporating additive technologies into the crisis-management system.</p> </abstract>ARTICLE2021-06-20T00:00:00.000+00:00Rzeszów as an example of a ‘new town’ tailored for the modern era<abstract> <title style='display:none'>Abstract</title> <p>The city life cycle is an issue that can be considered from many perspectives. Klaassen’s period cycle is the basic model of city life: urbanisation– suburbanisation–deurbanisation–reurbanisation. In each of these periods, cities develop by, building and transforming their structures. This article presents various approaches to shaping new urban spaces using the city of Rzeszów as an example. In the city’s history, three periods are distinguished during which structures referred to as the ‘new town’ were created in the 16<sup>th</sup> and 20<sup>th</sup> centuries and continue to be created now. After analysing the site-forming processes, the most important features of new-town urban systems are compared.</p> </abstract>ARTICLE2021-04-22T00:00:00.000+00:00A review of modern materials used in military camouflage within the radar frequency range<abstract> <title style='display:none'>Abstract</title> <p>The article presents an overview of materials which can be employed used to camouflage objects on the modern battlefield in the radar frequency range.</p> </abstract>ARTICLE2021-02-10T00:00:00.000+00:00Mixing effects in the river downstream from pollution discharge point<abstract> <title style='display:none'>Abstract</title> <p>This paper follows the propagation of pollution in a river with a rectangular cross-section of the river bed and a variable cross-sectional velocity. The calculations were made for steady flows and steady pollutant concentrations. To approximate the velocity distribution in the river bed a set of equations for current and vorticity functions was solved. The distribution of pollutant concentrations in the river was calculated from a bidirectional advection and turbulent diffusion equation. Analysis of the distribution of concentrations leads to the conclusion that the effects of transverse advection associated with a lateral inflow of pollutants disappear relatively quickly. Therefore, the distribution of concentrations in cross sections further downstream from the point of pollutant discharge can be determined quite accurately just from an advection-diffusion model, with no transverse advection effects included. Such a level of accuracy is usually sufficient to assess the impact of a pollution source on the aquatic environment. The transverse mixing of pollutants in the stream proceeds slowly and creates a large mixing zone in which the concentrations of pollutants (low but still significant for water quality) can be detected in cross-sections that are remote from the pollutant discharge point. Transverse advection may be ignored while calculating concentrations in remote cross sections at straight watercourse sections and in steady state conditions.</p> </abstract>ARTICLE2021-04-18T00:00:00.000+00:00HMM-based phoneme speech recognition system for the control and command of industrial robots<abstract> <title style='display:none'>Abstract</title> <p>In recent years, the integration of human-robot interaction with speech recognition has gained a lot of pace in the manufacturing industries. Conventional methods to control the robots include semi-autonomous, fully-autonomous, and wired methods. Operating through a teaching pendant or a joystick is easy to implement but is not effective when the robot is deployed to perform complex repetitive tasks. Speech and touch are natural ways of communicating for humans and speech recognition, being the best option, is a heavily researched technology. In this study, we aim at developing a stable and robust speech recognition system to allow humans to communicate with machines (robotic-arm) in a seamless manner. This paper investigates the potential of the linear predictive coding technique to develop a stable and robust HMM-based phoneme speech recognition system for applications in robotics. Our system is divided into three segments: a microphone array, a voice module, and a robotic arm with three degrees of freedom (DOF). To validate our approach, we performed experiments with simple and complex sentences for various robotic activities such as manipulating a cube and pick and place tasks. Moreover, we also analyzed the test results to rectify problems including accuracy and recognition score.</p> </abstract>ARTICLE2021-02-05T00:00:00.000+00:00Safety analysis of the Żelazny Most tailings pond: qualitative evaluation of the preventive measures effectiveness<abstract><title style='display:none'>Abstract</title><p>In this paper, a qualitative safety analysis of the Żelazny Most tailings pond is addressed. This object is one of the largest facilities of this type in the world being a crucial element in the technological line of copper production in KGHM Polska Miedź S.A. The assessment of the effectiveness of two types of preventive measures, i.e., relief wells and loading berms, is investigated based on displacement and stability analysis of two 2D cross-sections in a technical section of the dam. The study shows that the considered preventive measures generally have a positive impact on increasing the safety level of the structure during its further raise. In particular, their effectiveness is most evident when they are applied simultaneously. It is eventually suggested that the selection of final solutions to be applied on the facility should be based on the quantitative 3D analysis.</p></abstract>ARTICLE2021-06-18T00:00:00.000+00:00The effect of changing graphitization temperature toward bio-graphite from Palm Kernel Shell<abstract> <title style='display:none'>Abstract</title> <p>This paper focuses on the relationship between heat treatment temperature toward structural transformation from amorphous carbon to highly graphitic carbon material during a production stage.The following report discusses a simple strategy to convert the palm kernel shell (PKS) into highly crystalline, high quality graphite via simple two-step process. The production involves impregnation of catalyst followed by thermal treatment. Both XRD and Raman spectroscopy allowed the observation of microstructural change of the prepared sample at temperature ranging from 1000°C to 1400°C using Ferum catalyst. From XRD pattern it can be observed that as graphitization temperature increased, the degree of graphitization also increased. Overall sample prepared at higher temperature 1400°C shows a higher degree of graphitization. PKS sample graphitized at 1400°C with the aid of Ferum catalyst shows a sharp intensified peak at 2θ = 26.5° reflecting formation of highly crystalline graphite structure. Raman spectrum also suggests similar results to XRD in which PKS-1400 shows the presence of large amount of graphitic structure as the value of (Id/Ig) ratio is lower than in other samples. HRTEM analysis visibly shows define lattice fringe, which further confirms the structural transformation from amorphous to highly ordered graphitic carbon structure. Overall, good quality graphitic carbon structure from Palm Kernel shell was succesfully synthesised via utilization of PKS, Ferum catalsyt and heat treatment method.</p> </abstract>ARTICLE2021-06-12T00:00:00.000+00:00Investigation of corrosion rate of X55CrMo14 stainless steel at 65% nitrate acid at 348 K<abstract> <title style='display:none'>Abstract</title> <p>A number of factors determine the mechanical, but also physical and chemical properties. One of the most important are the steel microstructure and its working conditions. A few corrosion processes in crevices and awkward corners can be avoided at the design stage (low roughness parameters, round-section and other). But still the construction material is exposed to corrosion. These steels often come into contact with an aggressive environment based on nitric acid. Stainless steel is more and more often used in many sectors of industry.</p> <p>The purpose of this article is to investigate corrosion resistance in different time (48, 96, 144, 192, 240, 288, 336, 384 and 432 hours) using weight loss and profile roughness parameters of martensitic steel in grade X55CrMo14 in nitric acid 65% pure-basic at temperature 348 K. Corrosion tests show that the tested steel in nitric acid as a corrosive environments is characterized through continuous corrosion process whose measure may be surface roughness.</p> </abstract>ARTICLE2021-06-12T00:00:00.000+00:00Barriers to the implementation of innovations in information systems in SMEs<abstract> <title style='display:none'>Abstract</title> <p>Information management and information flow is an important element in the strategy of developing and running a company. The need to supervise information makes it necessary to implement numerous innovations that improve the method of information management correlated with the proper reception, selection and analysis - in both external and internal information flow. This paper presents the results of research that allowed for the assessment of barriers that arise during the implementation of innovative solutions in small and medium-sized enterprises (service MSEs). On the basis of the conducted research, it was found that the mental barrier is not always crucial from the point of view of modern technologies implementation. And the determination to implement information management innovations may be forced by the necessity of the document exchange acceleration. The success of innovative solutions e.g. in the financial services industry (in SMEs) is closely related to the technological capabilities of the enterprise - the technological barrier is crucial in this type of enterprises. Especially, taking into account the assumption that employees are highly motivated to implement new products.</p> </abstract>ARTICLE2021-06-12T00:00:00.000+00:00Agri-Food 4.0 and Innovations: Revamping the Supply Chain Operations<abstract> <title style='display:none'>Abstract</title> <p>The agri-food sector contributes significantly to economic and social advancements globally despite numerous challenges such as food safety and security, demand and supply gaps, product quality, traceability, etc. Digital technologies offer effective and sustainable ways to these challenges through reduced human interference and improved data-accuracy. Innovations led by digital transformations in the agri-food supply chains (AFSCs) are the main aim of ‘Agri-Food 4.0’. This brings significant transformations in the agri-food sector by reducing food wastage, real-time product monitoring, reducing scalability issues, etc. This paper presents a systematic review of the innovations in the agri-food for digital technologies such as internet-of-things, artificial intelligence, big data, RFID, robotics, block-chain technology, etc. The employment of these technologies from the ‘farm to fork’ along AFSC emphasizes a review of 159 articles solicited from different sources. This paper also highlights digitization in developing smart, sensible, and sustainable agri-food supply chain systems.</p> </abstract>ARTICLE2021-06-12T00:00:00.000+00:00Analysing the machines working time utilization for improvement purposes<abstract> <title style='display:none'>Abstract</title> <p>The article is a case study of the use of snapshot observation to analyse the factors causing time losses at selected laser burner stations, and to propose changes that will increase the effective utilization of working time. The purpose of this paper is to determine the best and worst utilization of working time at the examined workplaces, analyse the amount of time lost and identify the causes of losses, and propose solutions that will improve the utilization of working time. According to the snapshot observation, procedure 2 main - work and non-work - time fractions and 10 detailed time fractions in the working day were distinguished, and their percentage share for the analysed workstations was calculated. Analyses of the working day time utilization depending on the type of machines, days of observation, single shifts were done and selected results were averaged. The paper indicates that organizational and technical aspects, as well as the employees’ faults, were the main reasons for time losses. Research has shown that the generally examined group of workstations was characterized by a high utilization level of working time. An unfavourable phenomenon was the ratio of the main time to the auxiliary time, the high share of the maintenance time fraction of the workstations, and incorrect organization of the interoperation transport, low workers motivation, rush, and routine. It was found that further improvement of work efficiency and reduce time losses requires paying attention to the optimization of employees’ working conditions, training, motivation systems, and implementation of lean concept tools and MES/CMMS solutions into production.</p> </abstract>ARTICLE2021-06-12T00:00:00.000+00:00en-us-1