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Fuel economy and improved vehicle safety are key to the modernisation of cars. With more vehicles on the road, efficient lighting is essential. LED vehicle lighting technology offers energy savings, improves fuel consumption, extends service life and reduces service costs, making it a popular choice for higherend vehicles. Improved brightness in low visibility reduces driver reaction times. This study investigates a lighting retrofit for an MP13 lift truck and its effect on alternator loads. The results show significant improvements in brightness, energy consumption and lifetime compared to conventional bulbs. Strategically placed LED lights improve safety and reduce engine load, especially when the platform is stationary. [ABSTRACT FROM AUTHOR]

Recent research in Technology-Enhanced Learning (TEL) demonstrated several important benefits that semantic technologies can bring to the TEL domain. An underlying assumption for most of these research efforts is the existence of a domain ontology. The second unspoken assumption follows that educators will build domain ontologies for their courses. However, ontologies are hard to build, especially for not-tech-savvy users. Tools for ontology extraction from text aim to overcome this problem. We have conducted an empirical study with educators, both from Information Technology (IT) and non-IT domains, where they used current ontology extraction tools to build domain ontologies for their courses from their existing course material. Based on the obtained study results we have drawn conclusions about the existing ontology extraction tools and provided recommendations for their future development so that they can be beneficial for the TEL domain. (Contains 11 tables, 1 footnote and 2 figures.)

Presented paper is focused on comparison of three types of steel for production of tubes with shaped internal surface for applications in energy producing industry. Simulations were performed in Deform-3D software with usage of finite elements method. Steels 20MnCr5, C10 and 34CrNiMo6 were selected for simulations. Obtained results are showing deformation, stress, strain and temperature during cold drawing of tubes with shaped internal surface and also resulting comparison of three tested materials depending on the course of load during the forming process. As a conclusion of the presented research is comparison of presented three steels according to the simulation results. Presented paper has potential to increase knowledge base in the area of forming tubes with shaped internal surface. Obtained results can contribute to a proper selection of tool material, coatings and process set up for forming process of tubes with shaped internal surface. [ABSTRACT FROM AUTHOR]

Presented article is focused on the effect of friction coefficient of drawing mandrel surface on parameters of the drawing process. Drawing of tubes with the internally shaped surface is complex problematics. Creation of internal ribbing is determined by many deformation zones which affect stress and strain acting in forming process. Finite elements method application on solving presented problematics gives the opportunity to simulate and optimize process without expensive prototype mandrels. Research if mainly focused on the shape and properties of drawing mandrel. For simulations purposes were selected three friction coefficients which are common in drawing process in dependence of tool surface and coating in combination with lubrication. Acquired results show behavior of strains and stresses in drawing process. Maximal values of observed parameters accompanied with jump changes are mostly pronounced in inner layer. Obtained values are applicable for setting of lubrication in drawing process from the perspective of elimination jump changes in stresses which can shorten life time of mandrel and lower quality of final product. [ABSTRACT FROM AUTHOR]

This article is focused on the prediction model of surface roughness parameters of structural steel created by plasma arc cutting. Optimization of the cutting process is very important from both quality and economy point of view. The presented paper shows the carrying out of the experiment with the specification of the design of experiments method. In these experiments, the influence of three factors ‐ the plasma current, the traverse speed, and plasma gas pressure was observed. Experimental material was selected structural steel S355. Along with the influence of controllable process factors was observed the influence of different plasma gasses. Application of different plasma gas significantly changes surface quality. The result of each experiment series is a regression function that can predict the Rz values according to the process parameters at given intervals. Presented equations can be applied in the production process for adjusting the plasma cutting process in order to achieve required surface quality. [ABSTRACT FROM AUTHOR]

This article is focused on studying and analysing the efficiency of the machinability of a high strength aluminium alloy (EN AW-AlZn5.5MgCu) in the high feed milling. The introduction of the article provides a brief description of high feed milling technology and presents best known research regards to the subject. The research of the time efficiency and economic efficiency of high feed milling of aluminium alloys consists of realization of two groups of experiments. The first group consists of four experiments carried out by progressive technology of high feed milling, and the second group contains one experiment conducted using conventional milling technology. The assessment of efficiency consists in determining the overall time and economic efficiency and also in comparison to the machining of aluminium alloys by high feed milling technology with conventional machining technology. The best results were obtained when the machining parameters were: cutting speed of 550 m/min, travel speed of 10600 mm/min, and feed per tooth of 0.85 mm. The material was removed in the contour roughing phase with a 42 mm plungecutting router. Using this cutter, it is possible to produce 19 pieces of components in a hour, which is more than half of the specified requirement. The production of components under the conditions and with this type of high feed milling cutter is more than 75 % shorter than production by a conventional method. [ABSTRACT FROM AUTHOR]

With the steady development of online education and online learning environments, possibilities to support social interactions between students have advanced significantly. This study examined the relationship between indicators of social presence and academic performance. Social presence is defined as students' ability to engage socially with an online learning community. The results of a multiple regression analysis showed that certain indicators of social presence were significant predictors of final grades in a master's level computer science online course. Moreover, the study also revealed that teaching presence moderated the association between social presence and academic performance, indicating that a course design that increased the level of meaningful interactions between students had a significant impact on the development of social presence, and thus could positively affect students' academic performance. This is especially important in situations when discussions are introduced to promote the development of learning outcomes assessed in courses. Another implication of our results is that indicators of social presence can be used for early detection of students at risk of failing a course. Findings inform research and practice in the emerging field of learning analytics by prompting the opportunities to offer actionable insights into the reasons why certain students are lagging behind. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Mechanical Engineering the National Technical University of Ukraine 'Kyiv Polytechnic Institute' is the property of National Technical University of Ukraine KPI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The relative contents of Na,K-ATPase subunit mRNAs in rat renal cortex, ventricular myocardium, skeletal muscle (hind limb), liver and brain (cerebrum) were measured. Expressed per unit DNA, mRNA alpha 1 content was approximately 2-fold greater in the kidney and brain as compared to either heart, skeletal muscle or liver. The hierarchy of mRNA alpha 2 expression was brain > skeletal muscle > heart, whereas mRNA alpha 3 was restricted to brain. Beta 1 subunit mRNA content in both kidney and brain exceeded the abundance of liver mRNA beta 1 by approximately 7-fold. In all tissues examined, the combined abundances of the alpha subunit mRNAs exceeded the content of mRNA beta 1. The hierarchy of Na,K-ATPase activity expressed per unit DNA was brain > kidney > skeletal muscle = heart > liver. The sum of mRNA alpha as well as mRNA beta 1 content, expressed per g of tissue, was highest in brain and kidney. A statistically significant correlation between mRNA beta 1 content and Na,K-ATPase activity was evident. [ABSTRACT FROM AUTHOR]

The article deals with design and design of a thin-walled heat sink for the robot control system, the measurement of the transverse roughness of the touch surfaces and the programming procedure in Autodesk Inventor 2019 software. In this software, a design of the 3D model of the heat sink generated based on power supply and NC code generation for the Fanuc control system. The production it-self carried out on the CNC Vertical Machining Center Pinnacle 2100 with this control system. The longitudinal surface roughness was measured with a Mi-tutoyo SJ 400 dredger and the measurement result was the maximum Ra = 0.69 μm and Rz = 4.1 μμm.

The paper is focused on the influence of the coolant pressure on the surface roughness of the workpiece when machining stainless steels. The components were machined on a STAR SR-32J dual spindle machining center and an external cooling unit HYTEK CHAV 160/150-AF-F-OL was used for cooling. Two stainless steel components were investigated, namely the gas control valve rod and the high-pressure control valve housing, which require low roughness Ra after machining (less than 0.375 and 0.25 micrometers respectively). The first component was tested at 8 different pressures in the range of 150 bar - 10 bar and the second component at 4 different pressures in the range of 120 bar - 10 bar. The roughness parameters were measured by the contact method using the MITUTOYO Surftest SJ-410 Roughness Tester and the Alicona InfiniteFocus optical microscope. Based on these sample input parameters, it was evaluated howmuch the pressure affects the surface quality or suggested its reduction due to the high cost of operation of the external high-pressure equipment.

This paper is focused on analysis of residual stress of functional surfaces and subsurface layers created by precision technologies of hard machining for progressive constructional materials of forging tools. Methods of experiments are oriented on monitoring of residual stress in surface which is created by hard turning (roughing and finishing operations). Subsequently these surfaces were etched in thin layers by electro-chemical polishing. The residual stress was monitored in each etched layer. The measuring was executed by portable X-ray diffractometer for detection of residual stress and structural phases. The results significantly indicate rise and distribution of residual stress in surface and subsurface layers and their impact on functional properties of surface integrity.

The incorporation of additive manufactured (AM) metal parts to real assemblies is a crucial issue for the increasing of their industrial utilization. The presented research is devoted to the electron beam welding (EBW) of dissimilar steel joints. Dissimilarity is defined by the various types of steel and manufacturing processes used for the creation of specimens. Conventional AISI 316 stainless steel, selective laser melted (SLM) SS 316L stainless steel, and SLM M300 maraging steel were welded at variable parameters in the form of a welding current and a welding velocity. EBW joints were evaluated considering the macroscopic and microscopic characteristics, as well as a reached microhardness. The obtained preliminary results represent important input data for the follow-up experiments focused on the setting of optimal EBW parameters of welding the dissimilar joints including SLM products, with the consideration of their basic macroscopical and microscopical characteristics, mechanical properties, and residual stresses.

We investigated the use of boron-doped diamond (BDD) with different surface morphologies for the enhanced detection of nine different peptides by matrix-assisted laser desorption/ionisation mass spectrometry (MALDI-MS). For the first time, we compared three different nanostructured BDD film morphologies (Continuous, Nanograss, and Nanotips) with differently terminated surfaces (-H, -O, and -F) to commercially available Ground Steel plates. All these surfaces were evaluated for their effectiveness in detecting the nine different peptides by MALDI-MS. Our results demonstrated that certain nanostructured BDD surfaces exhibited superior performance for the detection of especially hydrophobic peptides (e.g., bradykinin 1-7, substance P, and the renin substrate), with a limit of detection of down to 2.3 pM. Further investigation showed that hydrophobic peptides (e.g., bradykinin 1-7, substance P, and the renin substrate) were effectively detected on hydrogen-terminated BDD surfaces. On the other hand, the highly acidic negatively charged peptide adrenocorticotropic hormone fragment 18-39 was effectively identified on oxygen-/fluorine-terminated BDD surfaces. Furthermore, BDD surfaces reduced sodium adduct contamination significantly.

The detection of defects in aluminium alloys using eddy current testing (ECT) can be restricted by higher electrical conductivity. Considering the occurrence of discontinuities during the selective laser melting (SLM) process, checking the ability of the ECT method for the mentioned purpose could bring simple and fast material identification. The research described here is focused on the application of three ECT probes with different frequency ranges (0.3-100 kHz overall) for the identification of artificial defects in SLM aluminium alloy AlSi10Mg. Standard penetration depth for the mentioned frequency range and identification abilities of used probes expressed through lift-off diagrams precede the main part of the research. Experimental specimens were designed in four groups to check the signal sensitivity to variations in the size and depth of cavities. The signal behavior was evaluated according to notch-type and hole-type artificial defects' presence on the surface of the material and spherical cavities in subsurface layers, filled and unfilled by unmolten powder. The maximal penetration depth of the identified defect, the smallest detectable notch-type and hole-type artificial defect, the main characteristics of signal curves based on defect properties and circumstances for distinguishing between the application of measurement regime were stated. These conclusions represent baselines for the creation of ECT methodology for the defectoscopy of evaluated material.

The present study aimed to enhance the efficiency and efficacy of the Al/Cu joint production process implemented by the company VEMID Ltd., Jagodina, Serbia, by attaining sound joints within a very short welding time. For this purpose, the present study aimed at investigating the accuracy and the quality of the continuous drive friction welding (CDFW) process, as well as the optimum combination of CDFW parameters with highest joint efficiency in terms of investigated properties. The accuracy was estimated through an analysis of temperature-time curves recorded during CDFW using an infrared camera. The quality was evaluated through an investigation of the properties of Al/Cu joints produced using different friction (66.7, 88.9, and 133.3 MPa) and forging (88.9, 222.2, and 355.6 MPa) pressures and a constant total welding time (4 s) and rotational speed (2100 rpm). Thermal imaging with an infrared camera demonstrated that the actual total welding time was 15% longer compared to the nominal value. This was attributed to the slow pressure response of the pneumatic brake system. The relative changes in the maximum surface temperature ( T MS ) during the CDFW process corresponded to changes in welding pressures, indicating the potential of the thermal imaging method for monitoring and assessing this process. A preliminary investigation demonstrated that Al/Cu joints produced using welding pressures less than 88.9 MPa often displayed the presence of non-joined micro-regions at the Al/Cu interface and a significant thickness of interfacial Al 2 Cu (up to 1 µm). However, when friction pressure was set at 66.7 MPa, an increase in the forging pressure to 222.2 MPa eliminated the presence of non-joined micro-regions and reduced the thickness of Al 2 Cu to 0.5 µm on the average level. These Al/Cu joints achieved the highest joint efficiencies in terms of strength (100%) and ductility (61%). They exhibited an electrical conductivity higher than 92% of the theoretical value. A further increase in any welding pressure produced similar or deteriorated properties, accompanied by an increase in the consumption of raw materials and energy. Such turn of events was counterproductive to the original goal of increasing the efficiency and efficacy of the CDFW process.

The presented manuscript focuses on the influence of process parameters of abrasive water jet technology on the creation of non-transient erosive grooves. The processed stainless steel SS 316L is additively manufactured using the selective laser melting (SLM) method. Due to the distinct mechanical properties of this material resulting from the production process, the material was machined in two planes according to the direction of the printing layers. The experimental part employed a planned experiment utilizing the DoE (Design of Experiment) method. Experiments aimed at varying process parameters (traverse speed, standoff distance, abrasive mass flow) were conducted at a water pressure of 50 MPa, assessing the parameters' impact on the removed material and the properties of the resulting non-transient erosion groove. The properties of the erosion groove, such as shape and the material removal (area of erosion groove), were evaluated. The influences of process parameters on the observed parameters were assessed using the analysis of variance (ANOVA) method. Experiment preparation and setup were based on a thorough theoretical analysis of the machining process with the abrasive water jet (AWJ) method. The experiment also highlights the diverse properties of the SS 316L material prepared using the SLM method when machined with AWJ technology.

The identification of residual stresses (RS) in components made by selective laser melting (SLM) is necessary for subsequent technological optimization. The presented research is devoted to evaluating the influence of the combination of laser power (P), scanning velocity (v) and the rarely considered number of layers (n L ) on surface residual stresses in SLM stainless steel SS 316L. Experimental parameters were set based on the Design of Experiment (DoE) method, with follow-up X-ray diffraction (XRD) measurements and data processing using analysis of variance (ANOVA) and regression analysis. The obtained data are a valuable stepping-stone for the subsequent design of research focused on the application of sustainable eco-friendly Abrasive Water Jet (AWJ) peening for RS modification in the evaluated material.

Screen-printed sensors with chemically deposited boron-doped diamond electrodes (BDDE) were modified with different types of gold nanoparticles (AuNPs) according to a new original procedure. Physically and electrochemically deposited AuNPs had various sizes and also nanoporous character. They also differ in shape and density of surface coverage. The developed sensors were characterized using scanning electron microscopy and Raman spectroscopy. Their electrochemical properties were studied using cyclic voltammetry and electrochemical impedance spectrometry of selected outer sphere ([Ru(NH 3 ) 6 ]Cl 3 ) and inner sphere (K 3 [Fe(CN) 6 ], dopamine) redox markers. The application possibilities of such novel screen-printed sensors with BDDE modified by AuNPs were verified in the analysis of the neurotransmitter dopamine. The best analytical performance was achieved using printed sensors modified with the smallest AuNPs. The achieved limit of detection values in nanomolar concentrations (2.5 nmol L -1 ) are much lower than those of unmodified electrodes, which confirms the significant catalytic effects of gold nanoparticles on the surface of the working electrode. Sensors with the best electrochemical properties were successfully applied in the analysis of a model solution and spiked urine samples., (© 2023. The Author(s).)