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Experimental Investigation on the Advantages of Dry Machining over Wet Machining during Turning of AISI 1020 Steel
Full text linkIn this study, the experiment was conducted to investigate the advantage of dry machining over wet machining during turning of AISI 1020 steel using cemented carbide tool on a CNC lathe machine. Surface roughness and cutting temperature were measured by VOGEL surface roughness tester and infrared thermometer respectively. The experiments were conducted based on Taguchi L9 orthogonal array design. Surface roughness, cutting temperature, tool life, and machining cost were analyzed graphically. The average surface roughness and cutting temperature achieved with wet machining was 2.01 µm and 26.540C, which was 17.41% and 44.86% respectively, lower than dry machining. The high cutting temperature in dry turning result in short tool life, which was 41.15% shorter than wet turning. The machining cost of wet turning was about 56% greater than the cost of dry turning. The cost of coolant in wet turning is 42.88% greater than that of the cutting tools. The highest cost was shared by tool cost, which was 81.33% of the total cost for dry turning, while 70.00% of the total cost was shared by coolant cost for wet turning. Results revealed that dry turning is more economical than wet turning
Design and Development of an Electronic Sieving for Sand Separation using Node MCU System
Full text linkSand sieving is now considered one of the essential needs in the construction industry. Where businesses collaborate to find the best and highest-quality methods for extracting pure sand suitable for construction. These businesses always require high-quality machines to complete the process flawlessly. This is also to prove its market power and guarantee its products. This research talks about the various mechanisms for designing and manufacturing sand sieving. The sand sieving process expresses the filtering of sand from the rest of the components such as stones or gravel. The literature department studied ten different studies in the design and manufacture of sand sieving machine in different ways. Where these methods vary between using the engine and electricity and using the primitive manual method. After performing these machines several tests and evaluation of the process, it was found that the engine speed affected the energy consumed to sift the sand. Also, the sieve holes are affected by the size of the sifted sand. Where sieves are manufactured in different sizes to suit the size of the sand to be purified. On the other hand, this article contains the future recommendation of the machine to avoid errors and give effective results as needed
Development of a Crutch Substitute for Mimicking Human Natural Walking Gait
Full text linkIn order to resolve some of the disadvantages of conventional crutch designs, as well as some of the existing crutch-substitute devices, available on the market, a novel Exo-Limb crutch design is presented. The Exo-limb is a hands-free crutch meant to enhance and replace standard underarm crutches and other competitive products during injury rehabilitation. The focus of this research has been on creating a cost-effective passive device that mimics humans natural walking gait using purely mechanical components. Prior to the design, human natural treadmill walking was monitored by a 3D Motion Capture System and a reference end¢‚¬€œfoot trajectory with a ¢‚¬Ëœteardrop shape¢‚¬„¢ was acquired. Considering the design objectives, natural human walking and comfort, and other factors such as load capacity and weight of the device, the final design was determined. In order to satisfy the design objectives a kinematic synthesis, previously developed by one of the co-authors, is applied to test if the end¢‚¬€œfoot trajectory of the designed crutch substitute smoothly follows the desired reference, ¢‚¬Ëœteardrop shape¢‚¬„¢ in the vicinity of two specified task points, heel strike and toe off. A prototype of the final design was fabricated and its performance was tested by 2 mph treadmill walking. The research and developments made in this project with regard to mimicking the natural walking gait are important contributions that find applications in different areas, such as military, robotic locomotion, injury recovery and physical therapy
Industrial Robot Trajectory Stiffness Mapping for Hybrid Manufacturing Process
Full text linkThe application of using industrial robots in hybrid manufacturing is promising, but the heavy external load applied on robot system, including the weight of deposition extruder or the cutting force from machining process, affects the operation accuracy significantly. This paper proposed a new method for helping robot to find the best position and orientation to perform heavy duty tasks based on the current system stiffness. By analyzing the robot kinematic and stiffness matrix properties of robot, a new evaluation formulation has been established for mapping the trajectory¢‚¬„¢s stiffness within the robot¢‚¬„¢s working volumetric. The influence of different position and orientation for hybrid manufacturing working path in different scale has been discussed. Finally, a visualized evaluation map can be obtained to describe the stiffness difference of a robotic deposition working path at different positions and orientations. The method is important for improving the operation performance of robot system with current stiffness capability
Hardness and Indentation Size Effect in Cubic Boron Nitride Materials (BL and BH Groups)
Full text linkThis paper investigates the hardness and indentation size effect (ISE) in cubic boron nitride (cBN) materials, specifically focusing on two groups: BL (below 70 vol.% cBN) and BH (more than 70 vol.% cBN). The study examines the load dependence of hardness in both groups, determining the load at which hardness becomes constant. Fracture toughness, (by the length of the crack) around indentations, is also evaluated for load dependence. The materials were synthesized using different additive combinations (Al, TiC, TiN, Mo) and sintered under high pressure and temperature. Hardness was measured using a Vickers indenter, and the ISE was analyzed using Meyer\u27s law and the proportional sample resistance (PSR) model. Fracture toughness was calculated using the Niihara equation. Results show a significant ISE in BL materials, while BH materials exhibit less “load-hardness” dependence
Excellent Absorption of LaCoxO3 Over Full Solar Spectrum and Direct Photothermal Energy Storage of Ca(OH)2–LaCoxO3
Full text linkAbstract: Photothermal conversion is a vital way for solar energy applications. The strong absorption of near Infrared light is essential for excellent photothermal performance. In this study, we demonstrated that nano LaCoxO3 is able to harvest light intensely across the full solar spectrum with high photothermal temperature. A core-shell-like structure of LaCoxO3-coated Ca(OH)2 particles was fabricated and shows excellent photothermal conversion, high kinetics of dehydration and remarkable cycle stability of heat storage and release. The photothermal dehydration-conversion of Ca(OH)2 increases 8.4-fold. Results demonstrate the multifunctionality of LaCoxO3, intensifying light harvesting, high photothermal conversion, good stability, considerable strength, and porous framework favouring the performance of photothermal storage and release cycles. LaCoxO3–Ca(OH)2 composite can simultaneously harvest light and store thermal energy
3D Printing of β-TCP/S53P4 Scaffolds: Physicochemical, Mechanical, and Biological in vitro Evaluation
Full text linkAbstract: The focus of bone tissue engineering is on the new strategies for developing bioactive and resorbable scaffolds, which have become an alternative to the treatment of bone diseases and trauma. β-tricalcium phosphate (β-TCP) is considered resorbable and has excellent osteoconductivity. In an attempt to achieve good densification of the β-TCP scaffold and improve its biological properties, it arises the possibility of combining this material with S53P4 bioactive glass. Several techniques are used to produce bioceramic scaffolds, among them, direct ink writing (DIW) a type of additive manufacturing based on material extrusion, which allows the production of customized parts, with high complexity and good reproducibility. This work prepared β-TCP and β-TCP/S53P4 (β-TCP/10-S53P4 = 10% wt of S53P4 and β-TCP/20-S53P4 = 20% wt of S53P4) scaffolds by DIW. The ceramic inks showed pseudoplastic behavior and the 3D-printed scaffolds showed similar aspects to the digital model. Also, the β-TCP/S53P4 scaffolds (β-TCP/10-S53P4 = 1.6 ± 0.6 MPa and β-TCP/20-S53P4 = 2.1 ± 0.9 MPa) showed an increase in compressive strength when compared to β-TCP scaffolds (0.9 ± 0.1 MPa). All scaffolds showed apatite-mineralization ability in SBF after soaking for 7 and 14 days, being that the β-TCP/20-S53P4 scaffold showed a higher ability of apatite formation compared to the other scaffolds. Concerning the biological in vitro assays, all the scaffolds showed good cell viability. Thus, the β-TCP/S53P4 scaffolds showed adequate properties which become them, good candidates, to be used in bone tissue engineering
The Effect of Tool Rotation on Structure and Mechanical Properties in Friction Stir Welding Of Aluminum AA5052
Full text linkAbstract: Welding of aluminum alloy materials is often used in the industrial world, including those engaged in shipping, aircraft, and others. The welding method used to bind aluminum materials is Friction Stir Welding (FSW). Friction Stir Welding (FSW) is a simple welding method, namely by utilizing the heat energy generated from the friction of the shoulder tool with the material being welded. This study aimed to determine the effect of tool rotation on the physical and mechanical properties of Friction Stir Welding of Aluminum AA5052. The material used in this study was aluminum with the series AA5052 as the primary material. The friction stir welding process was carried out using CnC milling with parameters of the tool rotation speed of 1000, 1200, and 1500 rpm and a feed rate of 25 mm/minute. Physical analysis was carried out using macro photo observations with a USB Digital Microscope and microstructural observations with optical metallography. Mechanical observations were carried out using tensile testing and hardness testing. The microstructure in the weld nugget area shows good results with fine and dense grains that occur due to the dynamic recrystallization process. The highest tensile strength is 102.49 MPa in the 1000 rpm parameter. This is due to the material mixing process and good heat transfer
CAES Compressed Air Energy System: Dynamic Simulation & Optimization
Full text linkAbstract: A CAES (Compressed Air Energy System) plant can be considered as a storage system. The purpose is to store air under pressure and then use it, when required, to generate energy. The system is composed of a series of compressors and heat exchangers and the architecture of the plant aims to reduce compression work and improve storage efficiency. The storage tank can be different depending on the case and the final use, so a cave, a combustion chamber or an expander. Currently the plants that have been built are in Germany (plant built in 1978 with a rated power of 290 MW) and in the USA (built in 1991 with a rated power of 110 MW). In both configurations, the plants use saline caves as reservoirs. Lately, different types of plant are being studied, but they are still in the design phase.
The objective of the present work is, through a steady-state and then a dynamic simulation, to analyze the positive aspects of this technology and its criticalities, trying to optimize its layout. In addition, through a comparison with the few data available on existing plants, create a database of great interest for researchers and experts in the field. Finally, evaluate, based on the data obtained, the possible developments of technology in the context of the "low carbon transition" through the possible use of renewable sources, such as solar photovoltaic, wind and so on
Analysing the Elements that Affect People\u27s Behavioural Intention to Adopt Autonomous Vehicles
Full text linkAbstract: In order to get fresh insights into how behaviour is accepted at the individual and organisational levels, psychologists and sociologists have been studying the user acceptability of information technology for decades. Several techniques are used in the research\u27s pragmatic approach, which is carried out in the phases that follow. In phase I, a preliminary survey with 408 individuals was used to identify the important variables impacting behavioural intention to use an autonomous vehicle (AV). Experts in the fields of psychology, sociology, and computer science were questioned. Finally, the hypothesis was defined after the model had been built. In phase II, a survey research methodology was used with an additional 482 individuals to empirically validate and improve the conceptual model. A tool for information visualisation was created in phase III to fill the gap between theoretical ideas and real-world business needs. According to the results, every construct in the conceptual model has a significant impact on consumers\u27 behavioural intentions (BI) to embrace AVs. Based on our assessment, the researcher proposes a theoretical AV technology acceptance model (AVTAM) by incorporating these determinants into the Unified Theory of Acceptance and Use of Technology (UTAUT2) model. This model takes into account self-efficacy, perceived safety, trust, anxiety, and legal regulations. The conclusion shows that the adoption of AV technology will be influenced by a number of factors, including the price of the equipment and the legal implications