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Understanding the fatigue behaviors of weld joints is significant in engineering practice. Rotary friction welding (RFW) can join the additively manufactured polymer components. Until now, no research has focused on the fatigue behavior of polymer components jointed via RFW. This study investigates the fatigue life of ABS/PC dissimilar components fabricated via RFW and proposes the fatigue mechanism based on the failure structure. This work uses five different cyclic loads and rotational speeds to investigate the fatigue life. The fatigue life of the RFW of ABS/PC dissimilar rods is better compared with the pure ABS and pure PC specimens due to weld and integrity microstructural changes resulting from the combination of ABS and PC materials. The number of cycles until the rupture of RFW of ABS/PC dissimilar components (y) can be determined by the cyclic load (x) according to the prediction equation of y = −838.25x2 − 2035.8x + 67,262. The fatigue life of the RFW of ABS/PC dissimilar components increase with the increased rotational speed. The number of cycles until rupture (y) can be determined by the different rotational speeds (x) according to the prediction equation of y = 315.21x2 + 2710.4x + 32,124.

In this study, effects of process parameters of Friction Stir Spot Welding were investigated on Al2024T3 which has poor weldability. Several spot welds were performed by the FSSW process on the 2mm aluminium sheets. The effects of main process parameters such as tool Rotational Speed (RS), Normal Plunge Depth (NPD), and Dwell Time (DT) on the joint strength were investigated. By increasing the tool rotational speed, the joint strength increased, consequently. The mean failure load improved 52% when the tool rotational speed increased from 800 rpm to 1120 rpm, whereas increasing the rotational speed from 1120 to 1600 did not have significant effect on the failure load. The results showed, increasing the normal plunge depth from 1.5 to 1.75 millimetre led to an increase in the failure load of spot welds by about 1.62 times. Also, the 3 seconds dwell time showed higher failure load compared to 2 and 5 seconds dwell time.

In this study mechanical properties of friction stir welded AM60 magnesium alloy in existence and lacking of alumina nanoparticles were examined. Microscopical analysis revealed peak condition could be made in 1200 rpm rotational speed, not only in the absence of reinforcing alumina nanoparticles but also in the presence of them. Adverse effects of higher strains in lowering grain size and higher temperatures in grain growth should be considered. In the existence of alumina nanoparticles in the matrix some areas of low content aluminum formed besides of high aluminum content of intermetallic compounds regions. Higher hardness and ultimate tensile strength achieved in optimum 1200 rpm rotational speed not only with alumina nanoparticles but also in the absence of alumina nanoparticles condition. Higher stresses and therefore lower agglomerated alumina nanoparticles resulted with increasing rotational speed. With alumina nanoparticles in matrix, lower grain size, higher hardness and higher ultimate tensile strength was attained.

The pump-jet propulsor(PJP) performances under various rotational speeds (20~50 r/s) are analyzed for further studying the influence of the Reynolds number (Re) on the hydrodynamics of PJP, before this, the calculation model is verified by using the experiment data, it proves the present numerical method is proper to make a further study. The results indicate both the hydrodynamic coefficients of PJP and PJP components and the contours with dimensionless variables are present high similarity, yet the Re has the slight effect on the components performance, among which, the force coefficient of rotor is the least affected, with a relative error no more than 1%. Followed is the force coefficient of rotor stator, the maximum error is 2.1%, since the force of duct and stator is so low that has the slight effect on PJP, the total force error is less than 2%. However, the torque coefficient error is bigger with a value of about 3%. Besides, it is found that all hydrodynamic coefficients vary monotonically with rotating speed, the higher Re caused by increasing the rotational speed will contribute to enhance the work ability of rotor, thus cause a lower pressure at vortex core, and change the trajectory of TLV.

Manganese ores are the major raw materials utilized in the production of manganese ferroalloys. A common problem in the production of manganese ferroalloys is the lack of knowledge regarding mineralogical and metallurgical properties of manganese ores. Decrepitation, which is described as the breakage or disintegration of the ore particles upon heating, is an important quality parameter of these ores. The decrepitation Index (DI), which is the parameter used to describe the extent of decrepitation, is described as the ratio of mass of particles

This study aims to determine the performance of a plastic mulch hole making machine and its electrical power requirements. The study begins by providing speed variations on the engine sprocket, calculating the working capacity of the machine, and analysing the power requirements of the electric motor. The results showed that the engine sprocket could perform an optimal rotation speed for punching holes in plastic mulch. Most holes were created in the treatment with a rotational speed of 70 rpm, 16 holes per 5 m of plastic mulch. Overall, the performance of the plastic mulch punching machine has been able to provide fixes in making holes in mulch plastic. Of the three treatments, the speed variations of the plastic mulch punching machine provided perforations with the criteria of perfect and partial perforation. The highest percentage of ideal perforation was found in the treatment with a rotational speed of 29 rpm, 86%, and the lowest was found in the treatment with a rotational speed of 25 rpm, 9.3%. The coefficient of determination between the rotational speed of the machine and the performance of the machine to punch holes in the plastic mulch can be modelled by a polynomial equation. [ABSTRACT FROM AUTHOR]

A developed version of friction stir brazing (FSB) entitled friction stir vibration brazing (FSVB) was presented to fabricate low carbon steel joint using %67wt Sn-%33wt Pb alloy as a braze metal. This attempt aims to analyze the role of mechanical vibration and rotational speed on microstructure and mechanical behaviors of the brazed samples. Furthermore, the thermal analysis, the thickness of intermetallic compounds (IMCs) layers, and void volume percentage at the joint interface were studied. It was concluded that the temperature during the joining process increased and the coherency of the joint interface enhanced while FSVB was applied instead of FSB. In addition, the grains in the joint zone under the FSVB process were smaller than those produced under the conventional FSB process. The results also showed that the mechanical performance, namely hardness, and shear strength increased and the thickness of the IMCs layer along with the void volume percentage in the brazed sample decreased as rotational speed increased from 850 to 1150 rpm. The results indicated that rotational speeds over 1150 rpm had detrimental effects on mechanical properties. This is related to the effect of high heat input and induced temperature on brazing flow and filler-base metal interaction. [ABSTRACT FROM AUTHOR]

Copyright of Bearing is the property of Bearing Editorial Office 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 longitudinal vibration of the propulsion shaft system is a challenging issue for marine noise management. We conducted various static and dynamic tests on our built test rig for the shafting system, presenting the results in this paper. By combining experimental data and the particle swarm optimization algorithm, we identified the structural parameters that are difficult to obtain. With these parameters we establish a completed theoretical model of a shaft system containing branches, analyze how and why static thrust affects vibration, and give quantitative results of the force transmissibility. Our work provides a reference for subsequent researchers. [ABSTRACT FROM AUTHOR]

With the development of techniques for the use of gears and their many shapes and types, the mechanical need for them has become great, especially in the use of them in the field of cars, and the most important of these types are bevel gears, as these gears are considered essential in differential gears. The use of differential gears in mechanics in general helps to reduce noise in the movement, but there must be vibration resulting from this movement, and accordingly, bevel gears and the effect of rotating gears on free vibration have been studied. Variable gears were used according to a simulation program and the study of the free vibrations that occur to them. The effect of rotational speed on the natural vibration greatly affects the transmission of movement in the car and increases the fault distortions that occur in the differential gearbox. The result shows the natural vibration reached at the speed of 5000 rpm, and the value of the vibration reached 3564.5 Hz, which is the highest value compared to the remaining speed. The distortion at a speed of 1,000 rpm. The process of rotation and natural vibration affects the deformations and stresses that get on the gears themselves. The natural vibration is greatly reduced when the number of clamping places for the differential gear is increased. Compared to the presence of two spinning tires, the vibration value reduced. At a rotating speed of 5000 rpm, it is known that increasing the rotational speed raises the value 3015.9 Hz with one tire revolution with one tire rotation, the huge strains influence the little gears in the differential gearbox. The greatest value of distortion is 0.00067 m at 5000 rpm, which is the largest value of deformation compared to the rest of the employed rotational rates with one tire revolution. [ABSTRACT FROM AUTHOR]

Background: During the mushroom production process, about one-fifth of the mushroom gets lost. The mushroom residues (MR) are rich in nutrients and can be utilized in diverse applications. Therefore, the goal of this research was to modify a local hammermill to improve the performance of chopping mushroom residues to be efficient used as a by-product. Results: The experiments were conducted on a hammermill without and with six screen diameters, three drum rotational speeds, three feed rates, two average moisture content and two hammer rotation tracks (long–short). Then, chopper experiments were carried out with a focus on a specified size, power consumption and energy required. The findings of using any size screen offered little productivity since after a short time, the chopping MR was built blocks around the drum and blades. But using no screen gives these phenomena disappear. The chopping MR performed well in long track conditions, with a feeding rate of 700 kg/h, a drum speed of 300 rpm and moisture content of 43%. Conclusions: The chopping operation had the best at feed rate of 700 kg/h, drum speed of 3000 rpm and 43% moisture content of which gave the appropriate MWD of 5.54 and 5.32 mm, consumed power of 1114.35 and 1189.125 W and required specific energy of 1.59 and 1.7 kW h/Mg for short and long tracks, respectively, and also largest mean weight diameter under such conditions due to a decrease in the amount of mushroom residues and an increase in their dryness, which increases the fragmentation impact of hammers on mushroom remnants. [ABSTRACT FROM AUTHOR]

Copyright of Bearing is the property of Bearing Editorial Office 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.)

Copyright of Bearing is the property of Bearing Editorial Office 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 study has investigated the effects of three factors, which were feeding rate, the rotational speed, and the type of used hammers on the some important indicators that could reflecting the performance of the hammer mill. These indicators were: grinding fineness (%), productivity (Kg hr-1 ), and consumed energy (KW). The experiment parameters were organized using a Randomized Complete Design (CRD) with three replications. The results showed that by increasing the feeding rate from 2 cm up to 4 cm, the fineness of grinding, productivity and energy consumed for both crops increased. The results also indicated that by increasing the rotational speed, the productivity and energy consumption increased, while the speed of 2154 rpm achieved the fineness grinding of barley and corn. The results also indicated that the use of conventional hammer led to the highest value concerning the fineness of grinding, and to the highest energy consumptions for both crops, barley, and corn. As for productivity, the manufactured hammer led to the highest values for both crops. However, considering the triple interaction between the studied factors (grinding fineness, productivity, and consumed energy), the manufactured hammer led to the highest value in productivity. [ABSTRACT FROM AUTHOR]

Copyright of Bearing is the property of Bearing Editorial Office 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.)

Real-time monitoring of UAV motor speed is crucial for enhancing control performance and ensuring flight safety. However, this task faces challenges such as difficult sensor installation and high costs. This study introduces a wireless rotational speed sensing system based on a UAV-rotary triboelectric nanogenerator (UR-TENG). By employing a carefully designed structure with soft contact and a freestanding-triboelectric-layer mode, UR-TENG exhibits characteristics like low friction, affordability, ease of production, and self-powering capability. This eliminates the need for an external power source and addresses the complexity of installation in the limited space of UAVs. Experimental findings demonstrate that UR-TENG possesses high sensitivity and stability, maintaining the structural integrity of the UAV. The goodness of fit is notably high at 0.99959, with a maximum error rate of only 0.014 within a range of 6270 rpm. Moreover, UR-TENG integrates with a microcontroller unit (MCU) and external circuitry to form a monitoring system. This system transmits electrical signals to a PC via a Wi-Fi module, facilitating real-time rotational speed sensing and anomaly detection. Finally, a practical application demonstration on a UAV validates the adaptability of UR-TENG to complex operational environments. This study presents a promising approach for online rotation monitoring of UAV motors, with potential for commercialization, and introduces new avenues for TENG application in UAV technology.

The hydrogen circulating pump is an essential component of hydrogen fuel cell systems. It plays a vital role in improving hydrogen utilization efficiency and optimizing hydrothermal control capabilities. Due to its compact design, high efficiency, and outstanding low-temperature adaption performance, the lobe hydrogen circulating pump has excellent potential for hydrogen recirculation in fuel cell vehicles (FCVs). This paper investigated the internal flow characteristics of a lobe hydrogen pump for FCV under different rotational speeds by experiments and computational fluid dynamics (CFD). Moreover, the lobe rotor domain was calculated using the dynamic mesh method. The effects of different rotating speeds on transient pressure pulsation, exhaust flow rate, external noise, and vibration were studied. The result reveals that the volumetric efficiency improves with the increased lobe rotor speed when the pressure ratio remains constant. The vibration acceleration level (VAL) and the external noise also increase. The vibration is most significant at the pump casing outlet and tends to decrease as the frequency increases. The sound pressure level spectrum has a discrete character in the low-frequency band, with peaks mainly concentrated at the rotating fundamental frequency and harmonics. The middle and high frequency bands have prominent broadband characteristics, and the energy is relatively concentrated. [Display omitted] • 3D simulation method for hydrogen pump based on the dynamic mesh was presented. • The effect of rotational speeds on unsteady characteristics was obtained. • The leakage characteristics of rotor-rotor and rotor-casing clearances were revealed. • The features of vibration and noise at different rotational speeds were revealed. [ABSTRACT FROM AUTHOR]

Commercially pure aluminium is a prominent material for aviation, construction and automotive industries; however, its poor mechanical properties have restricted its usages. Friction stir process (FSP) is a novel technique of metal strengthening. Process parameters likes rotational speed, travelling speed and probe depth etc. affects the quality of the deformed zone and consequently on the properties of deformed material. In the present study commercially pure aluminium was subjected to FSD using CNC milling machine. A mild steel tool was carefully chosen and fabricated to have uniform defect free stir zone. The present study aimed to optimise the processing parameters for generating internal defect-free stir zone. The macrostructure observations of transverse cross-section were used to get an indication of the stir zone quality. Micro hardness of stirred samples were also evaluated and correlated with the all processing parameters. The result showed that improved mechanical property (Hardness is improved by 68%) with defect-free stir zone was observed at 1500 rpm rotational speed, 2 mm/min travelling speed and at 1.2 mm probe depth. Likewise through this process crystallite size was refined to 36 micron metre in a single pass from the underlying crystallite size of 96 micron metre. [ABSTRACT FROM AUTHOR]

This paper presents the design of a permanent magnet generator for a gearless backyard wind turbine. The magnetisation characteristics of the rotor steel and the stator at different field strength ranges were considered at the design stage and mathematically described using a model in Matlab. The detailed calculations and the design of the planar model were carried out using FEMM software. The high-quality results obtained from the calculations shown in the paper made it possible to make a real model of the generator. This paper presents views of the stator package, the rotor, the entire generator and selected test results. The parameter of this turbine that distinguishes it from a wide range of manufactured generators is its low, non-standard rotational speed and low breakaway torque, which allows the power plant to start in winds of approximately 2 m/s. Other advantages of this generator is its low weight resulting from the use of a light rotor and light alloys for the generator housing. [ABSTRACT FROM AUTHOR]

One of the most important machines in the olive oil extraction line is the horizontal three-phase centrifugal separator machine or Tricanter. The purpose of this paper is to evaluate the machine designed on the basis of Tricanter and to evaluate the quality of extracted olive oil. For this purpose, four different olive cultivars from Gilan Province in Iran were used. In this research the rotational speed of the Tricanter machine was tested at three levels of 2 500, 3 000, and 3 500 rpm and the content of water added to olive paste was used at three levels of 10, 20, and 30% of the paste mass. Peroxide value (PV) and percentage of acidity were measured for oil extracted from all four olive cultivars. The results of the analysis of variance (ANOVA) test showed that rotational speed and the content of added water had an effect on the acidity and PV for all samples of olive cultivars. The measured values showed that the best speed for the Tricanter machine is 3 500 rpm. At this rotational speed, the peroxide and acidity values are lower than the standard values. [ABSTRACT FROM AUTHOR]

All-hydraulic drill has been widely employed in core drilling recently, which results in larger Weight on Bit (WOB) and higher rotational speed to diamond bit. Thus, new requirements of diamond bit abrasiveness are needed to satisfy the severe challenges. To investigate the effects of WOB and rotational speed on the friction and wear properties of diamond bit matrix, an experimental scheme with 2 factors and 4 levels was designed to carry on the friction and wear test, and two kinds of Fe based diamond bit matrix formula systems, i.e. elemental metal powders and pre-alloyed powders were considered. The samples were manufactured by hot-pressing. Test results indicate that the abrasion loss of the Fe based samples increase with the raise of WOB and rotational speed, while the WOB has a bigger significance. The wear mechanism of the bit matrix is dominated by adhesive wear under smaller WOB and lower rotational speed, while abrasive were will become more and more important with the increase of WOB. Besides, samples from the pre-alloyed powders formula system have better performance than the ones from elemental system, the abrasion can be reduced by up to 15.52%, when under the same test conditions. [ABSTRACT FROM AUTHOR]

Friction stir welding equipment was used to weld 3 mm thick 6082 aluminum alloy and T2 copper, through metallurgical microscopy, hardness testings tensile testing, etc.explore the impacts of rotational speed on the organization and mechanical properties of welded joints. The results show that: Intermittent defects always exist at the interface of the joint, alternating distribution of aluminum and copper, and uniform mixing of the two materials; The microhardness distribution of the joint shows that the highest value appears in the weld core area with hardness of 210 HV, aluminum and copper side heat affected zone hardness have decreased, the lowest value for the aluminum side heat affected zone of about 60 H V; with the increase in speedy the tensile strength increases first and then decreases, when the spindle speed of 1 000 r/min, welding speed of 50 mm/min, the optimal weld forming effect, the tensile strength can reach 255 MPa, the fracture shape becomes more uniform with the increase of rotational speed, and the toughness nest increases, showing a stratified distribution. The fracture location is the aluminum copper bond, and the crack extends along the interface defect, showing mixed brittle ductile fracture at low speed and ductile fracture at high speed. [ABSTRACT FROM AUTHOR]

The object of research is granulation of mineral fertilizers by the rolling method. One of the most problematic places is the uncertainty of the conditions of the temperature regime of granulation. The paper considers the technology for obtaining enlarged urea granules of prolonged action. It is indicated that an increase in the diameter of the granules to 7–10 mm increases the efficiency of the use of mineral fertilizers by the consumer. It is proposed to obtain large carbamide granules by rolling in a plate granulator. It is indicated that the setting of the optimal operating parameters of the tray granulator is an important factor in the efficient operation of the equipment. A scheme of a pilot plant for granulating mineral fertilizers is presented, a methodology for conducting experimental studies and design parameters of a plate granulator are described. It is indicated that in the process of experimental studies, the design parameters changed: the tilt angle of the plate, the height of the side and the frequency of rotation of the plate, the angle of opening of the spray jet by the hydraulic nozzle. In the process of research, the influence of regime and technological parameters, namely, the temperature of the layer on the plate is studied. As a result of experimental studies, the optimal ranges of design and regime-technological parameters for obtaining enlarged carbamide granules in a plate granulator were revealed. The influence of the location of the nozzle for spraying the melt on the layer relative to the plane of the plate is shown, which results in the particle size distribution of the granular product. It is indicated that a higher content of the commercial fraction in the finished product is observed when the layer in the left sector of the upper part of the plate is irrigated by the rising melt. A technique for determining the static strength of the obtained carbamide granules is given. A calculation equation for determining the static strength of a granule is presented. A diagram of a laboratory device for determining the static strength of granules is presented, which made it possible to determine the values of the static strength of granules for individual fractions, namely: for coarse, fine and commercial fractions. It is shown that the obtained values correlate well with standardized indicators. [ABSTRACT FROM AUTHOR]

Operational parameters of a Tunnel Boring Machine (TBM) under different geological properties have significant influence on muck removal performance. To improve the muck removal performance for Yinsong Tunnel TMB, tuff and granite properties were surveyed by geological detection in the tunnel project, and the optimization of advancement and rotational speed of cutterhead was investigated. The muck model was established by discrete element method (DEM), considering the shape characteristic of muck. The whole muck removal process was simulated, then the influence of the advancement speed and rotational speed on muck removal performance in tuff and granite stratum was studied via numerical simulations. Based on simulation results, the muck removal performance evaluation system of TBM is built using fuzzy mathematics and evaluation theory. Ultimately, optimal operation parameters in the tunnel project is obtained after comprehensive evaluation. The results indicated that the optimum advancement speed should be 7 r/min in both tuff and granite stratum, while the optimal rotational speed was 6 r/min in granite and 5.5 r/min in tuff respectively. Based on TBM engineering application, the size characteristic of muck was obtained from on-site muck specimen analysis and the muck removal performance of TBM under different operation and rock conditions was compared to validate the simulation method. These findings could provide guidance for TBM operation to improve muck removal performance in different geological conditions. [ABSTRACT FROM AUTHOR]

Copyright of Bearing is the property of Bearing Editorial Office 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.)

• This study performs a full-scale field test using shield machine to cut a diaphragm wall. • The cutterhead design and machine operation parameters are recommended. • The test shows that shield machine can effectively break steel reinforced concrete wall. • Cutter wear and wall vibration are relatively small when machine is properly operated. Shield tunneling during metro construction frequently hits steel reinforced concrete diaphragm walls. A high risk is involved in using a shield machine to cut through a diaphragm wall owing to limited theoretical research and engineering experience. To evaluate the performance of the shield machine and obtain feasible operation parameters, this study conducts a full-scale field test using a shield machine to cut through a diaphragm wall in Suzhou, China. The machine has a diameter of 6.84 m, equipped with 38 disc cutters and 48 scrapers. The wall has a width of 8.8 m, height of 9.7 m, and thickness of 0.6 m, reinforced with 25 mm and 28 mm diameter main steel rebars. The study finds: 1) the shield machine has adequate capacity to cut the diaphragm wall with small wear (maximum amplitude of 0.7 mm) to disc cutters and light damage to scrapers; 2) the concrete is mainly damaged under compression shear and peel-off with 95 % of particle size smaller than 10 cm, whereas the steel rebars are broken under the combined effects of compression shear and pull-apart with five damage modes identified based on different damage mechanism; and 3) a low advance rate (1–2 mm/min) and medium rotational speed (0.6 rpm) are recommended such that the machine can cut the wall smoothly with wall acceleration below 0.15 g and maintains its thrust and toque close to 10 % and 15 % of rated thrust and torque, respectively. The findings prove the feasibility of using a shield machine to cut through a diaphragm wall, and provide guidance for project implementation. [ABSTRACT FROM AUTHOR]

Friction stir lap welding (FSLW) technology was utilized to join 2 mm-thick 2A12-T42 aluminum alloy plates in the current study. Experimental findings demonstrated successful plate joining without welding defects across rotational speeds ranging from 400 to 600 rpm. Higher rotational speeds facilitated ample material flow, resulting in joints that are free of hole defects. The presence of a step can be attributed to a non-synergistic material flow caused by the shoulder and pin. The fracture behavior of the joint is primarily influenced by joint formation factors, such as the distribution of the aluminum cladding (alclad) layer and effective lap width (ELW), as well as the microstructure. The continuous distribution of the alclad layer promotes crack propagation into the nugget zone (NZ). In cases where the ELW is inadequate (at 400 rpm), shear fracture occurs due to crack propagation along the NZ. With an increase in ELW (at 600 rpm), crack propagation is hindered by grain refinement in the NZ, causing the crack to propagate along the weaker thermomechanically affected zone (TMAZ) leading to tensile fracture. [ABSTRACT FROM AUTHOR]

The article describes the design and operation of an experimental grain seeder equipped with roller seeding units with truncated rubber cones on the valves. Moreover, graphical and experimental dependences of the uneven distribution of seeds along the length of the furrow during the sowing of winter wheat Clavdia 2 on the speed of rotation of the roller, the diameter of the upper part of the spike and the angle of inclination of the spikes of the experimental seeding unit with truncated rubber cones on the valve are presented. The work on studying the influence of the seeding unit designs was carried out by comparing the basic seeder SZ-5,4 with an experimental seeder equipped with new roller seeding units with truncated rubber cones on the valves. The results of the research showed that an experimental seeder with roller seeding units with truncated rubber cones on the valves steadily performs the process of sowing seeds of winter wheat Clavdia 2 in compliance with all necessary agrotechnical requirements. With the improvement of sowing quality indicators, there is a decrease in the instability of the overall seeding rate, the uneven distribution of seeds along the length of the furrow, damage to the seed material, which, in turn, leads to an increase in the yield of the cultivated crop.

The objective of this study was to investigate the influences of the main parameters of friction stir welding (FSW) on the residual stresses remained in the FSW of Al 2024-T6. The main parameters were tool rotational speed and tool transverse speed. The effect of these parameters on the residual stresses was studied in both finite element simulation and hole drilling strain gauge measurement. The results showed a good agreement between the numerical results and the experimental outcomes. The change in transverse speed from 25 to 31.5 mm/min resulted in increase of longitudinal residual stresses in welding centerline in which the longitudinal residual stress was increased at the tool rotational speed of 1120 rpm and 1600 rpm about 12.5% and 2.67%, respectively. The results showed that at the low rotational speed, the strain rate had the most effect on the residual stresses whereas at the high rotational speed, some residual stress was released due to the generated heat in the weld zone.

The mechanical vibration causes health issues to drivers, such as backache, spinal cord injury, etc. In this regard, a tractor engine plays important role. Tractors without chassis are equipped with a balancer unit reducing the secondary engine vibrating force and decreasing the engine and tractor vibration. The paper presented investigates the effects of balancer on secondary vibration. In this research, the root mean square (RMS) of vibration was computed for specific periods of engine work. Effects of rotational speed and engine load on engine vibration in two modes with and without balancer were investigated. The results showed that, at full engine load, increasing the engine speed resulted in increasing the vibration in both observed modes. Balancer utilization reduced the vibration by 22.3% on average. At fixed rotational speed, increasing load caused an increase in vibration in both observed modes. At 1400 rpm rotational speed and 125 Nm torque, balancer utilization managed to reduce the RMS of secondary vibration by 38.9%. Furthermore, at 250 Nm, RMS vibrations were reduced by 21.3% in comparison to no balancer mode. At full load, variable rotational speed, the balancer significantly reduced vibration by 29% on average. The balancer proved to be more efficient at lower torques.

Rotational speed and temperature measurements of an engine blade surface play a vital role in the performance detection of an engine. We proposed a wireless passive LC sensor based on thick-film integration technology to integrate the sensor in situ on the surface of the rotating part, which can be used to monitor the rotational speed and temperature of the rotating part. The reflection signal generated by the impedance mismatch is output in the form of voltage through the detection circuit such that the synchronous online measurement of rotational speed and temperature is realized by analyzing the time slot of adjacent troughs and the amplitude of the output voltage. In addition, we used laser drilling, screen printing, high-temperature sintering, and other technologies to integrate the sensor in situ on the surface of the ceramic turntable, which is lightweight. Finally, the test was conducted by setting up a rotational speed-high-temperature composite experimental platform, and the results showed that the sensor can work normally in the range of 25–830°C, and the rotational speed measurement range was 50–400rpm. The consistency of the rotational speed measurement was suitable, the maximum error was less than 1%, and the work was stable within 180 min.

This study addresses the pressing need for eco-friendly potable water production, exploring the promising avenue of solar distillation. To overcome limitations in traditional systems, the author introduces the modified spherical solar still (MSSS), featuring a rotating ball within the design. A comprehensive experimental investigation compared MSSS performance with reference spherical distiller (CSSS) across energetic, exergetic, economic, and environmental (4E) dimensions. Key factors explored included: rotation speeds (0.2–1.2 rpm), wick material on the rotating ball, and thermal storage material (PCM) beneath the ball (desert sand, copper grits, or their mixture). The optimal MSSS configuration was identified: Rotation speed: 0.8 rpm (40 % yield increase), wick material: 57 % distillate enhancement at 0.8 rpm, and combined, these conditions yielded a remarkable 103 % distillate improvement compared to CSSS (7160 vs. 3525 mL/m2.day) and an efficiency of 59.5 %. Exergy efficiency also surpassed CSSS: 4.2 % for MSSS with PCM vs. 3.1 % for CSSS. Notably, the cost per liter of distilled water dropped significantly: $0.024 for MSSS with PCM compared to $0.066 for CSSS. Environmentally, MSSS with PCM saved 27.7 tons of CO 2 annually. Lastly, the enviroeconomic parameter (Z′) rose from 335 for CSSS to 365 for MSSS with PCM. • Study assessed modified spherical solar still (MSSS) with various speeds and PCMs. • MSSS with PCM at 0.75 rpm showed 103 % improvement, 59.5 % efficiency. • Exergy efficiencies at 0.75 rpm with PCM: CSSS 3.1 %, MSSS 4.2 %. • Cost analysis: CSSS $0.066/L, MSSS $0.043/L, MSSS with PCM $0.024/L. [ABSTRACT FROM AUTHOR]

Drilling is one of the most important surgical steps and bone fracture repair. In this step, the temperature may exceed 47 °C and thermal necrosis may occur, which has irreversible consequences. Knowing the amount of heat transferred to the bone and its changes can be effective in recognizing this heat damage and minimizing it. In this research, it was tried to estimate the amount of heat flux entering the bone during the drilling process using the inverse heat transfer method. Drilling tests were performed on cow bone samples and the temperature changes at the hole location were measured using the inverse heat conduction transfer method. The amount of heat input was estimated. The K-type thermocouple is used to measure temperature. The diaphysis fragment of the cow's thigh (middle part), which has a length of about 90 mm and the thickness of the cortical bone in this range is about 8–10 mm, was used. Also, to ease the tests, the beginning and end parts of the fresh femur were cut with a saw. The results show that the maximum heat flux occurs earlier than the maximum temperature. It was observed that the maximum heat flux and the maximum temperature rise with the increase of the rotational speed and the diameter of the tool. As the feed speed rises, first the maximum temperature and maximum heat flux decrease and then increase. By tripling the feed speed, the maximum heat flux decreases by about 20%. The highest percentage rise in temperature and heat flux occurs with a rise in rotational speed, which is around 130–140%. After the rotational speed, increasing the drill diameter increases the temperature up to about 66.7%. The results can be used to prevent thermal necrosis because the maximum heat flux is visible before the occurrence of the maximum temperature. [ABSTRACT FROM AUTHOR]

• Optimised three port, radial-flow gas wave ejector with curved channel is presented. • Designed and established the first radial-flow gas wave ejector platform. • A study on the impact of rotational speed on device performance was conducted, revealing a potential enhancement of 13.25 % in device ejection rate and a corresponding increase in device total efficiency by 11.86 %. • Through simulation validation, it is observed that the flow losses of the equipment exhibit a trend of initial reduction followed by subsequent increase as the rotational speed is elevated. The gas wave ejector (GWE) is a device that enables energy transfer between gases at different pressures through pressure waves. We conduct an experimental and simulation study on a novel radial-flow GWE, named DUT-R1, designed to harness centrifugal force to enhance mass and energy transfer efficiencies. Considering the significant influence of rotational speed (n) on the pressure waves and flow losses, we examine the relationship between the n of the DUT-R1 and both its ejection rate (ξ) and total efficiency (η T). Experimental data demonstrate that the GWE can attain the highest ξ and η T at an optimal designed rotational velocity (n d) when the pressure ports remain fixed. Simulations suggest that the primary cause can be attributed to the disruption of the ideal wave system. And when the equipment is equipped with ports matched to the n d , a consistent increase ξ is observed as the n d increases from 2000 r/min to 4000 r/min, resulting in a maximum improvement of 13.25 %. The simulation results demonstrate that increasing n enhances the suction capacity of the equipment through the inputting of shaft power (P). However, η T initially increases and then decreases as the n d increases, with a maximum improvement of 11.86 %. The simulation provides an explanation for the observed variations in η T during the experimental investigation by illustrating that flow losses initially decrease and then subsequently increase with an increasing value of n. [ABSTRACT FROM AUTHOR]

Porous carbon fiber-reinforced Al-Si alloy matrix composites and carbon fiber felt-reinforced Al-Si alloy matrix composites with carbon content of 10 wt.% were prepared by die casting. The dry tribological properties of these two composites and Al-Si alloy were studied using a ball-on-disc rotational tribometer in the rotational speed range of 300 r/min to 1000 r/min, and the wear mechanisms were analyzed in combination with the wear morphology. The results show that the friction coefficient and wear rate of these two composites are lower than the Al-Si alloy at different speeds. With the increase in rotational speed, the friction coefficient of the two composites and Al-Si alloy first increases and then decreases, and the wear rate gradually increases. The wear mechanisms of the two composites and Al-Si alloy change from abrasive wear and adhesive wear to delamination wear, but the node speed of the change in the wear mechanism of the composites to delamination wear is higher, and the wear degree is relatively slight. In addition, the comprehensive tribological properties of carbon fiber felt-reinforced Al-Si alloy matrix composites are better than the porous carbon fiber-reinforced Al-Si alloy matrix composites.

The friction spot welding (FSpW) method was used to weld 2198-T8 Al-Li alloy at rotational speeds of 500 rpm, 1000 rpm, and 1800 rpm. It was shown that the grains in the FSpW joints were transformed from “pancake” grains to fine equiaxed grains by the heat input of welding, and the reinforcing phases of S’ and θ were all redissolved into the Al matrix. This leads to a decrease in the tensile strength of the FsPW joint compared to the base material and a change in the fracture mechanism from mixed ductile-brittle fracture to ductile fracture. Finally, the tensile properties of the welded joint depend on the size and morphology of the grains and their dislocation density. At the rotational speed setting of 1000 rpm in this paper, the mechanical properties of welded joints consisting of fine and uniformly distributed equiaxed grains are best. Therefore, a reasonable set of the rotational speed of FSpW can improve the mechanical properties of the welded joints of 2198-T8 Al-Li alloy.

To comply with the government's sports policy, schools at all levels and localities have systematically and actively promoted the game of table tennis, which has become one of the most popular sports in Taiwan. Loop ball is a current table tennis practice method that can improve table tennis skills. Players who master the techniques associated with loop ball can improve their fine scoring skills in table tennis. Therefore, the main purpose of this study was to establish a model for quantifying the flight speed and trajectory of the looping ball. Methods: A closed-form set of sixvariable nonlinear control equations was established to estimate the movement of a table tennis ball. Numerical calculations were conducted using the high-precision Runge-Kutta-Feiberg method, and differences between trajectories and key kinematic properties were discussed. Results: The results of the study found that side-spin drive generates more lateral Magnus force due to the lateral rotation rate than the other two loops. The lateral deviation of the landing point can reach 0.21 meters, with an offset angle of approximately 8.07°. A ball with a faster initial rotation of the sphere that was hit from a more outside contact point will fall faster with a drop point closer to the end of the table, increasing the amount of side deviation. Conclusion: This study quantitatively compared the degree of lateral deviation and drop in response to various angular side-spin rates relative to the initial position of the ball at the point of contact. In the future, this model can also be applied to calculations of table tennis ball movement characteristics under various conditions or circumstances. [ABSTRACT FROM AUTHOR]

The surface modification process with specific characteristics is an important subject to achieve the highperformance contact behavior of pair surfaces. (Low frequency) vibration-assisted machining is one of the interesting processes which fabricates large-scale textures. This process can fabricate textures with various geometries in regular periodic distances. Current research develops a novel configuration that employs low-frequency vibrations during face turning to fabricate various textures on the surface of Al-7075 flexibly and efficiently. Process characteristics (rotational speed and feed) are controlled to adjust texture geometry. Results showed that the dimple length has a direct relation to the rotational speed. However, dimples number presented a reverse relation to the feed and rotational speed. Reducing rotational speed from 90 to 31.5 rpm could decrease the dimple length up to 73% and increase the dimples number up to 68%. Texture density was evaluated according to surface parameters of Sdr and Sds. Contrasting effects of mentioned parameters on the wettability achieved the minimum contact angle in the optimum rotational speed of 63 rpm. In the same procedure and the case of the friction coefficient, the rotational speed of 45 rpm was determined as the optimum condition with the smallest friction coefficient. The optimum condition has been determined for the developed configuration and assumed constant and variable (specific variation interval) parameters. [ABSTRACT FROM AUTHOR]

During dissimilar friction stir welding (FSW) of Al-Mg2Si metal matrix composite and AA6061 aluminum alloy, the temperature field and heat generation were investigated using a 3-dimensional computational fluid dynamics (CFD) model and FLUENT software. The simulations were conducted for rotational speeds of 720, 920, and 1120 rpm. The welding experiments were carried out to validate the simulation results. About 70% of the heat is generated at the interface between the shoulder and the workpiece. The maximum temperature is predicted on the advancing side (AS). The difference between the peak temperatures on the AS and the retreating side (RS) is about 115 K. The effect of the rotational speed on the peak temperature is significant. The temperature distribution in the cross sections is asymmetric, which originates from different material velocities on the AS and RS. The peak temperature on the RS develops under the top surface, while the peak temperature on the AS develops on the surface. [ABSTRACT FROM AUTHOR]

The Taguchi method was employed to find the optimum values of friction stir welding parameters including welding speed, rotating speed, and tilt angle for joining AA6061-T6 aluminum alloys. The combined influences of these parameters were entirely analyzed. Statistical outcomes were investigated by the study of variances and signal-to-noise ratios. A Coupled Eulerian and Lagrangian technique is implemented to simulate and verify the optimal parameters during the friction stir welding. To verify results, a comparison between the welding process under optimized parameters with experimental and non-optimized parameters was simulated for the friction stir welding process. The material flow, strain rate, thermal behaviors, and mechanical properties of samples fabricated with optimal welding parameters are higher than those produced from the non-optimal parameters. It was also concluded that the grain size of the stir zone under optimal welding parameters (6–8 µm) is finer than that of non-optimal welding parameters (11–13 µm). Low uniform distribution of material element and coarse microstructure were some of the results of welding with non-optimized parameters. Based on residual stress analysis, the application of optimal joining conditions can decrease the peak tensile residual stress by about 38.3%. The much desirable results obtained in terms of microstructure and mechanical properties could be of great significance to the welding industry. [ABSTRACT FROM AUTHOR]

The aim of this study was to predict the temperatures on all surfaces of threedimensional models using the ANSYS 15.0 program. Firstly, the temperatures from the welding centre to the edges of the models of two aluminium alloys (AA-7075 & AA-2024) welded by friction stir welding process were perceived. Secondly, the distribution of temperatures from the start of the welding process to its end and the derivation of equations to predict the distribution of temperatures with the time spent in the welding process, along with the distribution of temperatures with the distance from the centre of the welding process were observed at different travel speeds of the welding cart (TS = 20, 40, 60, 100 mm/sec) and different speeds of the welding tool (TRS=900, 1050, 1200 rpm). The results indicate that the temperature increases with the increase in the rotational speed of the welding tool, while the temperature decreases with the increase in the travel speed of the welding cart. Another result is that the temperature distribution is not symmetrical. The highest values are in the welding centre and decrease significantly as the welding centre is moved away, and the highest temperatures can be reached between (75 - 80%) in the welding centre from the melting point of the two aluminium alloys welded together. It was also found that the temperatures increase significantly twenty seconds after the beginning of the welding process and, afterwards, the increase is small, and three equations were derived to predict the temperature distribution. [ABSTRACT FROM AUTHOR]