Radomila Konečná, Denisa Medvecká and Gianni Nicoletto
Additive manufacturing has recently expanded its potential with the development of selective laser melting (SLM) of metallic powders. This study investigates the relation between the mechanical properties and the microstructure of Ti6Al4V alloy produced by SLM followed by a hot isostatic pressing (HIP) treatment. HIP treatment minimizes the detrimental influence of material defects. Tensile specimens produced with reference to specific building axes were prepared using a Renishaw A250 system. It has been found that the tensile strength and elongation depend on specimen building direction. Microstructural and textural characterizations were carried out to identify the source of differences.
The windshield defrost system, in general, is a vehicle safety feature. Thus, its restricted by variety of directives. However, the OMEs’ benchmark targets could be even more demanding as the deicing process is in addition also part of passengers comfort. From vehicle design point of view the wind-shield defrost system is typically connected to HVAC unit (Heating, Ventilation and Air Conditioning). In the technical solution the windshield is heated via hot air convection. Nevertheless, other methods are becoming more and more popular, like directly heated glass by hot wire ohmic heating (heated glasses). The defrost CFD model should predict the ice layer thickness in time and space and in environmental conditions defined according to appropriate directives and technical solution. The accurate and fast modelling technique is essential part of a vehicle development, especially nowadays, where the optimization techniques area widely used and requires hundreds of simulations runs. Modelling requests are even increasing with modern pure electric vehicles (EVs), were the thermal and energy management is more demanding compared to the classical internal combustion engine (ICE) vehicles. The aim of the work is to verify possibility to model the ice layer thickness with simplified approach, which could be beneficial from computational time burden.
Tadeusz Głuski, Magdalena Patro, Andrzej Marczuk, Wojciech Misztal, Katarzyna Szwedziak and Żaneta Grzywacz
The size of all sensible heat balance components in livestock building varies in time, because it depends on time-varying weather factors. On the example of two buildings, sensible heat balance was shown on a daily basis. Measurements carried out in winter and spring in two livestock buildings with usable attics included measurements of air temperature and humidity inside and outside, air velocity in ventilation channels, and wind speed. Measuring devices were designed to record the results of measurements at intervals of 300s. During each such time interval, sensible heat losses by ventilation, heat losses by permeation through the barrier construction, and the amount of sensible heat produced by the animals were calculated. The results of measurements were shown in graphs. The study is important for the development of animal livestock building.
Józef Gorzelany, Justyna Belcar and Natalia Matłok
The study assesses the quality of malt from spring malting barley grown in the Podkarpackie Province, and delivered to the SAN Farmers' Cooperative in 2018. After the initial technological assessment in the laboratory of SAN, the grain was malted in the Department of Agricultural and Food Production Engineering at the Institute of Agricultural Sciences, Land Management and Environmental Protection of the University of Rzeszow. Moisture, protein content, runoff time, viscosity, pH, wort clarity, extract content and diastatic power were determined in the tested malt, as well as wort obtained from it in the process of mashing. The average parameters of protein content, extractivity of malt ground into flour, of pH and the wort extract were normative, while the other researched parameters did not meet high quality requirements. A high loss of grain mass was noted during malting. After laboratory tests of malt and wort, it was determined that part of the malting raw material is of high malting quality and can be used without modification in the brewhouse for the malting and mashing process.
The sieves’ manufacturers that want to be competitive at the market must have the implemented quality control system. Different methods, based on taking the sample, which is a representative of the total quantity of the forming sieves production, are applied for evaluation of the sieve’s conformity. The basic characteristics of this type of the quality function are control, measuring and testing of the forming sieves’ properties at the end of the manufacturing process. The objective is to detect and separate the products that deviate from the set criteria, to remain in the factory, then to be repaired if possible or discarded in the opposite case and thus to prevent delivery of the defective sieves to the paper manufacturers.
This is a study of a medical injection factory-Babylon carried out in order to achieve proper mechanical and morphological properties, PP has been injection molded by using cold runner injection molding machine with temperature variation (198, 200, 203……220°C) for ten samples. The physical and mechanical properties of PP product were examined. It has been found that the Shore hardness decreases linearly with injection molding temperature increasing. The tensile strength has a similar behavior to the hardness. However, it has been found that the MIF (Melt Index Flow) rates increases with the increase of injection molding temperature. The density of PP has been found for both virgin PP and the samples, it has been found that the density decreases with increasing operation temperature. FTIR (Fourier Transmission Infrared) spectra were taken for both samples with high and low operation temperature. Besides the SEM (Scanning Electronic Microscopy) test shows the difference in the morphology of the product surface and the PP product at high and low operation temperature. Moreover, for all these properties, the PP product exhibits good mechanical properties (hardness, tensile strength, density) for the samples produced at temperature lower than 207°C. While the physical properties such as MIF improved with injection temperature increasing, additionally, the SEM images show that the sample produced in low temperature have surface damage.
Katarína Stachová, Zdenko Stacho, Zuzana Papulová and Marek Jemala
The need for adaptation to rapid changes in the business environment, both on the part of employees and employers, implies dealing with new challenges, acquisition of new knowledge and skills and assumption of new roles and responsibilities. The base for companies is the availability of qualified human resources, which is ensured by the human resource management department mainly through an effective process of employee selection. The paper is oriented at the analysis of the current state of focus of organizations operating in Slovakia on systematicity and complexity of the selection process, the existence of an effective internal labor market and the regularity of development of used selection tools in the context of technological progress and changes in labor market requirements in regions of Slovakia. Results of the survey on (n = 343) enterprises show a positive trend, an increase of more than 10 percent in the orientation towards improvement of the process of employee selection, but on the other side it also confirm an increase in disparities between individual regions of Slovakia, some regions (Eastern Slovakia) progress much slower than the developed ones (Bratislava).
The article presents the results regarding the elimination of constraints in the production process of a power equipment subassembly, a boiler chamber, together with an analysis of the benefits resulting from this, both financial and non-financial. The significance of bottlenecks in the production process, ways of its identification and limitations - in general - are presented. The article is a case-study of an attempt to eliminate the bottleneck in the production process of the boiler chamber, which turned out to be the process of drilling and marking-off, and work stations representing these processes. In order to eliminate the limitation, it was decided to replace the existing tracing and drilling work with a numerically controlled device - a boring machine moved from the liquidated department.. As a result, labor-intensive, manual chambers marking-off and the process of drilling holes with a smaller diameter drill have been eliminated. A number of benefits has been demonstrated resulting from the elimination of the bottleneck in the process, first of all, it was possible to reduce the duration of the marking-off and drilling operations and reduce the costs of the boiler chamber production process.
Ryszard Kulig, Grzegorz Łysiak, Zbigniew Krzysiak, Monika Wójcik and Renata Różyło
This paper presents the results of pea straw compaction efficiency tests. The compliance of the tested material to pressure agglomeration was assessed depending on the compaction pressure used (45-113 MPa). The compaction was carried out using a Zwick testing machine, type Z020/TN2S, and a closed die pressing unit. It was found that, along with the pressure increase, the material density in the chamber increased (from 1.255 to 1.76 g∙cm−3), as well as the agglomerate's density (from 0.739 to 1.05 g∙cm−3) and the product's mechanical resistance (from 0.31 to 0.69 MPa). Increasing the compaction pressure in the analyzed range increased the unit value of compaction work, from 17.16 to 34.27 J·g−1.
The purpose of the paper was to determine the impact of UV-C irradiation of seed potatoes on the formation of tuber defects in the progeny crop. The field experiment was carried out in 2016-2018, and the object of research was potato plants of the Vineta, Lord and Owacja varieties. Different heights of the UV-C radiator above the chamber bottom (40-100 cm) and exposure times (1-30 min.) were used. Data was analyzed with the STATISTICA 13.3 program, at the assumed significance level α = 0.05, using a non-parametric test χ2 for multidimensional contingency tables. In the scope of the parameters of the chamber for UV irradiation of plant material adopted in the experiment, no statistically significant UV-C effect on potato tuber defects was demonstrated. In the potato tuber crop of the examined varieties, shape deformations in the form of kidney and spindle disease were identified. The crop of potato obtained from seed potatoes irradiated with UV-C demonstrated a lower percentage of deformed tubers, as compared to the control combination.