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This study investigated the effect of severe plastic deformation induced by friction stir back extrusion on microstructure, mechanical properties, and corrosion resistance of Al-Cu-Mg alloy containing 0.5 wt.% of lithium micro-alloy and Cu/Mg ratio of 3.8. The effect of the rotational speed of friction stir back extrusion in the range of 600-1200 rpm in the constant traverse speed of 20 mm/min was studied. The results show that the size of equiaxed grains formed during the friction stir back extrusion process due to dynamic recrystallization increases from 21.0 ± 2.3 to 29.6 ± 4.5 μm by enhancing rotational speed from 800 to 1200 rpm. The dominance of the temperature effect on the plastic strain on the surface of wires during the friction stir back extrusion process results in the formation of coarser grains at the surface of wires. Friction stir back extrusion by a rotational speed of 800 rpm and a traverse speed of 20 mm/min result in the maximum yield, tensile strength, and minimum corrosion rate of 353.56 ± 10.31, 509.91 ± 11.56 MPa, and 0.008 mm/year, respectively. The friction stir back extrusion process has increased at least 23, 39, and 29% in yield strength, ultimate tensile strength, and elongation compared to as-cast alloy. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny 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.)

Friction stir welding (FSW) is a widely employed welding process, in which advancing and rotational speeds consitute critical parameters shaping the welding outcome and affecting the temperature evolution. This work develops an experimental methodology to identify optimal FSW parameters based on real-time temperature measurement via a thermocouple integrated within the tool. Different rotational and welding speeds were tested on AA5083-H111 and AA6082-T6. Our results underscore the importance of attaining a minimum temperature threshold, specifically 0.65 times the solidus temperature, to ensure high-quality welds are reached. The latter are defined by combining temperature measurements with joint quality information obtained from cross-sectional views. Our research contributes to advancing the efficiency and effectiveness of friction stir welding in industrial settings. Furthermore, our findings suggest broad implications for the manufacturing industry, offering practical insights for enhancing weld quality and process optimization. [ABSTRACT FROM AUTHOR]

This paper presents the results of an experimental investigation into the cooling performance of a rotor-stator cavity with liquid nitrogen spraying. The experiments were conducted under varying rotational Reynolds numbers ranging from 1.70 × 106 to 5.12 × 106. The effects of rotational speed on temperature drop rate are studied and compared in detail, as well as the heat transfer coefficient distribution. Sufficient data, such as heat flux, injection rate, and injection pressure, were collected to provide a basis for further study in explaining the spray and evaporation over the cavity. It was found that the cooling performance of the rotating disc is strongly affected by the rotational speed. The short-term period exhibits a peak cooling rate of 14°C/s, in contrast to the sustained cooling rate during the spray process at rotational speeds of 500r/min, which amounts to 0.9°C/s. The occurrence of cavitation and evaporation within the nozzle results in a reduction of flow coefficient and fluctuation of the injection differential pressure. The transient cooling performance is well-explained by the temperature changes and cooling-down time under different rotational speeds. The analysis of the heat transfer coefficient is further enhanced through an evaluation of the convective and conductive heat transfer rates using a one-dimensional theoretical approach. The average temperature of the disc is expected to decrease by 100°C within a time frame no longer than 120 s. Additionally, after a duration of 120 s, the average heat transfer rate on the cold side is anticipated to surpass 8000 W/(m · K). [ABSTRACT FROM AUTHOR]

A variable-speed pump-turbine is the core component of a hydraulic storage and energy generation station. When the pump-turbine operates at a constant speed, its response to the power grid frequency is poor. In order to improve the hydraulic efficiency of the pumped storage unit, variable-speed units are used. However, there has been no numerical study on the effect of the rotational flow characteristics within the gap of a variable-speed pump-turbine. This paper calculates the flow characteristics within the gap of a variable-speed pump-turbine under three typical pump modes (maximum head minimum flow condition, minimum head maximum flow condition, and maximum speed condition). The research results indicate that the rotational speed significantly affects the pressure distribution, velocity distribution, and turbulent kinetic energy distribution within the crown and band gaps. The higher the speed, the larger the area of the high-pressure region before the runner inlet compared to other operating conditions, and similarly, the low-pressure area after the runner outlet is also larger than in other operating conditions. The change in speed mainly affects the internal flow field of the crown gap, with the most noticeable changes occurring in the pressure and flow velocity at the inlet and outlet of the crown gap. There is a clear trend of pressure drop and velocity increase within the gap as the speed increases. However, with the increase in speed, the pressure distribution and flow velocity within the band gap remain almost the same. In addition to speed changes, it is observed that the pressure within the gap and the flow velocity within the passages are also related to the head, especially in the condition of maximum head, where this relationship becomes more noticeable. [ABSTRACT FROM AUTHOR]

AbstractButt welds were produced on AA5154/AA7150 using the FSW method, and measurements were taken for the hardness and elongation percentage of each joint. Regression analysis was utilized to investigate the significance of each parameter and formulate a mathematical relationship. Welding was performed at 1200 rpm, with a welding speed of 90 mm/min and a tool diameter of 28 mm, resulting in defect-free welds. Failures were commonly observed at the pin and the side of AA7150. To decrease the ultimate tensile strength (UTS), the welding speed (WS) or tool rotational speed (TRS) was increased. As both TRS and WS constitute the nugget zone, variations in hardness distribution were noted across the weld zones. ANOVA was applied in this study to establish the relative importance and influence of each factor on UTS. The ANOVA results indicated that all parameters significantly impacted UTS. Specifically, WS contributed 41.42%, diameter contributed 17.57%, and TRS contributed 13.27%. A quadratic model was also developed to describe the relationship between the factors and UTS values. Based on the data, a range of 0.41% to 10.36% differences existed between projected and actual values. The strength of the model was evaluated using R-Squared (R-Sq.), resulting in an obtained R-Sq. value of 0.892. This value indicates a robust relationship between the predicted and actual values. [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 purpose of this study is to analyze the rotational speed characteristics of a spherical turbine start-up process, and the rotational speed characteristic of the spherical turbine is studied by numerical simulation. In order to ensure the reliability of the numerical simulation, the numerical simulation results at different flow rates are compared with the experimental results, and the results show that it is feasible to investigate the rotational speed characteristics of the spherical turbine using numerical simulation. The numerical results demonstrate that the start-up process of the spherical turbine can be separated into two stages: the start-up acceleration stage and the transition stage, which are followed by periodic fluctuations of the rotational speed. In addition, when the flow rate is 8 m3/h , the spherical turbine can self-start under the load coefficient (Bg) if less than 3×10−5. If the Bg is larger than 3×10−5 , the turbine fails to start-up. The failed start-up shares characteristics: the turbine only moves forward and backward alternately in a small angular range. However, eventually, the applied load torque dominates, and the turbine starts to reverse. It is found that the flow rate and the turbine rotational speed present a linear relationship under the no-load operating condition. [ABSTRACT FROM AUTHOR]

This paper presents a new type of hydraulic clutch operating by means of magnetorheological (MR) fluids and the results achieved from both theoretical analysis and experimental measurement. A hydraulic clutch system with MR working fluid and a rotating magnetic field located was designed. The clutch was based on the principle of using a rotating magnetic field created by an alternating current electromagnet to set the MR fluid in motion. To test the hydraulic clutch with a rotating magnetic field, MR fluids were produced by our laboratory, consisting of solid iron particles of various diameters mixed with a silicone oil. With MR working fluid and a rotating magnetic core was designed. The rheological properties of the MR fluids were assessed on the basis of tests carried out with a Brookfield DV2T rheometer equipped with a magnetic device for generating a magnetic field. The characteristics of the hydraulic clutch were tested on a specially built test stand. It was found that the torque transmitted by the clutch increased with the rotational speed of the magnetic field and with a lower rotational speed of the beaker in which the working fluid was placed. It was also found that the greatest torque occurred with the working fluid with the highest iron content. Based on the analysis of the structure and characteristics of the clutch in which the magnetic field is used, it has been shown that the design of the developed clutch is similar to that of an induction clutch, and its characteristics correspond to the characteristics of the eddy current clutch. Therefore, the proposed new clutch with MR fluid and rotating magnetic field can be applied to stationary power transmission systems in a manner similar to an eddy current clutch. [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.)

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.)

Enhancing fatigue life of thick-walled cylinders used for high-pressure application is an important design task. Cylindrical vessels find applications in oil and gas industries, food and chemical industries, nuclear reactors and gun barrels. They are susceptible to cracking due to high tensile stress caused by internal pressurization at their inner side during operation. Compressive residual stress can potentially help in suppressing inner cracks in such components to safeguard against any awkward situations. In this work, a hybrid rotational-swage autofrettage method is proposed to induce beneficial compressive residual stresses at the interior wall of a thick-walled cylinder. An analytical model is developed to determine the residual stresses in the process using Tresca yield criterion and its associated flow rule for non-hardening material behavior. The compressive residual stress generated in the hybrid autofrettage process is assessed for increase in the fatigue life of pressurized cylinders. To exemplify the process, cylinders of two different materials, viz. SS316 and Al7075-T6, are considered to be rotated while interfering at their inner side with an axially driven oversized AISI4340 mandrel. The design speeds of the cylinders for each material are obtained as a function of the swaging mandrel interference without contact separation during the process. The residual stresses in the cylinders are evaluated numerically, and the performance of the cylinders on enhancing the fatigue life under in-service internal pressurization is investigated using Paris law. [ABSTRACT FROM AUTHOR]

Solar stills are acknowledged as an environmentally friendly desalination method that addresses water scarcity issues in remote areas; however, they contend with a productivity challenge. This work presents a combination of novel arrangements for the spherical solar distiller (RBSD) to augment its productivity. Rotational sphere was anticipated. The influence of speed for RBSD (0, 0.5, 1, 1.5, and 2 rpm) with and without wick was tested. Also, the effect of utilizing a preheater to supply the RBSD with hot feed water under various preheating temperatures, specifically 45, 50, 55, 60, 65, and 70 °C with and without condenser was investigated. Results revealed that the optimized speed is 0.5 rpm and 1 rpm for the RBSD with and without wick, respectively, where the productivity rise reached 62 % and 45 %, respectively. Also, the best preheating temperature that provided the highest performance for RBSD was 65 °C, where the CSD produced 3250 mL/m2.day, while, at 0.5 rpm and 65 °C, the RBSD with a preheater produced 6200 mL/m2.day with an increase in productivity by 91 %. When integrating the external condenser to RBSD with wick and preheater, the productivity of RBSD (6800 mL/m2.day) was augmented by 116 % over that of the CSD (3150 mL/m2.day). Also, the thermal efficiency of CSD and RBSD with wick, preheater and condenser was 32 % and 62 %, respectively. Finally, the cost of distilled water for CSD, RBSD with wick, RBSD with wick and preheater, and RBSD with wick, preheater, and condenser was found to be 0.220$/L, 0.075$/L, 0.055$/L, and 0.030$/L, respectively.

This study investigated the impact of a cylindrical obstacle on convection in an inclined square cavity filled with water-Al2O3 nanofluid. Using the finite volume method, the problem was resolved by having the inner cylinder rotate adiabatically while other walls were thermally insulated. Additionally, the bottom wall was hotter than the top. The study examined the effects of cylindrical obstacle radius (0.1 ≤ R ≤ 0.2), rotation speed (-500 ≤ Ω ≤ 500), Richardson number (0.01 ≤ Ri ≤ 100), volumetric nanoparticle fraction (0.02), and Grashof number (Gr = 104 ) on heat transfer rate or Nusselt number. The results were compared with previous literature, and the influence of the cylindrical obstacle rotational speed on convection flow was evaluated. An increase in the counterclockwise angular rotating speed resulted in higher nanofluid flux. The heat transmission coefficient increased as the Richardson number decreased. The use of nanofluid in the enclosure increased the coefficient of heat flow through mixed convection. Finally, the study showed that the convection heat exchange is enhanced with the increase in the radius. Moreover, an enhancement of the Nusselt number around 46% was reported for the cylinder, under Gr=10000, ∅=0.02, =45° and Ri= 10.

In this paper, we conduct a comprehensive numerical investigation of a ducted wind turbine under various rotational speeds, focusing on aspects such as boundary layer thickness and momentum thickness. Our study utilizes advanced computational fluid dynamics techniques to assess the intricate flow characteristics and aerodynamics of the ducted wind turbine, providing a detailed understanding of its operation under different speed conditions. The primary objectives are to comprehend the effect of the wind turbine's rotational speed on the boundary layer thickness and the momentum thickness, two crucial parameters influencing the turbine's performance and efficiency. Our findings reveal a significant correlation between the increase in rotational speed and the growth of flow separation, a phenomenon typically indicated by an expansion in the area of negative wall shear stress. This research contributes valuable insights into the behavior of ducted wind turbines at varying rotational speeds, and the acquired knowledge could potentially be utilized in designing and improving wind turbine systems to achieve better performance and enhanced operational efficiency. [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.)

This study investigated the impact of a cylindrical obstacle on convection in an inclined square cavity filled with water-Al2O3 nanofluid. Using the finite volume method, the problem was resolved by having the inner cylinder rotate adiabatically while other walls were thermally insulated. Additionally, the bottom wall was hotter than the top. The study examined the effects of cylindrical obstacle radius (0.1 ≤ R ≤ 0.2), rotation speed (-500 ≤ Ω ≤ 500), Richardson number (0.01 ≤ Ri ≤ 100), volumetric nanoparticle fraction (0.02), and Grashof number (Gr = 104) on heat transfer rate or Nusselt number. The results were compared with previous literature, and the influence of the cylindrical obstacle rotational speed on convection flow was evaluated. An increase in the counterclockwise angular rotating speed resulted in higher nanofluid flux. The heat transmission coefficient increased as the Richardson number decreased. The use of nanofluid in the enclosure increased the coefficient of heat flow through mixed convection. Finally, the study showed that the convection heat exchange is enhanced with the increase in the radius. Moreover, an enhancement of the Nusselt number around 46% was reported for the cylinder, under Gr=10000, Φ=0.02, γ=45° and Ri= 10. [ABSTRACT FROM AUTHOR]

Additive friction stir deposition (AFSD) is a solid state coating process as well as a developing solid state additive manufacturing technology. AFSD has numerous advantages over friction surfacing coating technology. However, extensive research has demonstrated that a relationship between microstructure and mechanical properties exists at present. On the other hand, a few research focus on temperature field evolution.The temperature field during AFSD is examined in this paper using a combined experimental-numerical approach. According to characterizations of AFSD thermal process, AFSD was classified into friction preheating stages and steady deposition stages. The friction preheating model and the steady deposition heat model are both established. The experiment is carried out to confirm the temperature difference between the simulation and the experiment, where experimental and numerical results correspond well. The AFSD process parameters include rotational speed, feed speed, and deposition rate. The purpose of this research is to examine the effect of process parameters on heat input during the production of aluminum alloy coating by AFSD. The results shows that rotational speed is a critical element that influences heat input. Overall, the comparisons of experimental and numerical results show that the numerical model's accuracy is satisfactory, and the effect of process parameters on heat input was thoroughly investigated. [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 adoption of additive manufacturing (AM) to complement conventional manufacturing to produce industrial components has been widely accepted. This is critical to the fabrication of designs with high complexity, which traditional manufacturing cannot match. In this regard, a commercial Pelton turbine with a traditional design was improved using both reverse engineering and hydro-dynamic finite element method simulations to produce a new design. Then, the performance of our new design is experimentally evaluated in terms of its rotational speed. In our new design, using the Design for AM (DfAM), several drawbacks of the traditional Pelton turbine design (e.g., improper welding and alignment and blunt splitters that lead to a heeling effect) were overcome by the following steps: (i) employing computational fluid dynamics analysis, (ii) consequently, extracting key geometrical characteristics from the original design, such as the number of buckets, runner wheel diameter, and bucket width, and length (iii) finally, referencing other design parameters using generally known empirical data. DfAM techniques were applied to reduce the post-processing requirements of additively manufactured turbine buckets, considering minimum feature size and avoidance of support structures on water-contacted surfaces, as well as simple and manual support removal. The new design in this study exhibits high rotational speeds ranging from 8.2 to 32.73% at an inlet pressure of 5 MPa and different nozzle angles. [ABSTRACT FROM AUTHOR]

Introduction: Rotary nickel–titanium files are subjected to shear and flexural stresses during instrumentation. Increasing the rotational speed may reduce the shear stresses but can deteriorate the fatigue life of the file. This in vitro study aimed to address the influence of three rotational speeds 300, 500, and 700 RPM on the apical force and torque generated during instrumentation as well as on file fracture. Materials and Methods: A total of 48 simulated canals were divided into three groups: 300, 500, and 700 RPM (n = 16). Each canal was instrumented using a ProTaper Next XA orifice opener to prepare the coronal third and an X2 shaper to prepare the middle and apical thirds. A new set of files (XA and X2) was used to prepare four canals. A customized setup was used to evaluate the maximum apical force and torque corresponding to each third of the canal. The files were inspected for deformation or fracture using a stereomicroscope. Force and torque data were analyzed using analysis of variance and Post hoc Tukey test at 5% significance. Results: Five hundred and 700 RPM generated a significantly lower apical force and torque than 300 RPM at all canal thirds (P < 0.001). However, 700 RPM was superior to 500 RPM at the coronal third only (P < 0.001). No incidence of deformation or fracture was reported in any group. Conclusions: In resin artificial canals, increasing the rotational speed of the tested ProTaper Next files resulted in significantly less apical force and torque without increasing the incidence of fracture. Further studies involving natural teeth are required to validate these results using natural teeth. [ABSTRACT FROM AUTHOR]

Copyright of Misr Journal of Agricultural Engineering is the property of Egyptian National Agricultural Library (ENAL) 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 utilization of aluminium alloy composite materials is increased progressively in automotive, aerospace, and sports allocations due to their distinct physical and mechanical properties. The conventional metal joining process is not suitable for joining the composite material. The present work of silicon carbide (SiC) compacted aluminium alloy (AA6061) composite surface is joined by friction stir welding (FSW) process under the rotational speed of 800, 1200, and 1600 rpm. Influences of tool rotational speed on welding interface quality mechanical and fatigue properties of AA6061/SiC composite surface are evaluated. The internal defect area of the weld joint is detected by radiograph inspection, and its surface morphology is analyzed through the Scanning Electron Microscope (SEM) apparatus. It revealed that the coarse aggregated inter-metallic structure with an effective interface of weldment was observed. The 1200 rpm (rotational speed) performed AA6061 composite found enhanced yield and tensile strength of 23.7% and 25.66% improvement compared to the yield and tensile strength of weldment operated under 800 rpm rotational speed. The hardness of composite weldment is increased significantly with increased tool rotational speed. The maximum hardness of 88HV is by 1200 rpm performed weld joint. Sample 3 performed higher fatigue life (1.8 × 106 cycles) without failure. [ABSTRACT FROM AUTHOR]

Friction stir welding (FSW) is a widely employed welding process, in which advancing and rotational speeds consitute critical parameters shaping the welding outcome and affecting the temperature evolution. This work develops an experimental methodology to identify optimal FSW parameters based on real-time temperature measurement via a thermocouple integrated within the tool. Different rotational and welding speeds were tested on AA5083-H111 and AA6082-T6. Our results underscore the importance of attaining a minimum temperature threshold, specifically 0.65 times the solidus temperature, to ensure high-quality welds are reached. The latter are defined by combining temperature measurements with joint quality information obtained from cross-sectional views. Our research contributes to advancing the efficiency and effectiveness of friction stir welding in industrial settings. Furthermore, our findings suggest broad implications for the manufacturing industry, offering practical insights for enhancing weld quality and process optimization.

This paper presents a new type of hydraulic clutch operating by means of magnetorheological (MR) fluids and the results achieved from both theoretical analysis and experimental measurement. A hydraulic clutch system with MR working fluid and a rotating magnetic field located was designed. The clutch was based on the principle of using a rotating magnetic field created by an alternating current electromagnet to set the MR fluid in motion. To test the hydraulic clutch with a rotating magnetic field, MR fluids were produced by our laboratory, consisting of solid iron particles of various diameters mixed with a silicone oil. With MR working fluid and a rotating magnetic core was designed. The rheological properties of the MR fluids were assessed on the basis of tests carried out with a Brookfield DV2T rheometer equipped with a magnetic device for generating a magnetic field. The characteristics of the hydraulic clutch were tested on a specially built test stand. It was found that the torque transmitted by the clutch increased with the rotational speed of the magnetic field and with a lower rotational speed of the beaker in which the working fluid was placed. It was also found that the greatest torque occurred with the working fluid with the highest iron content. Based on the analysis of the structure and characteristics of the clutch in which the magnetic field is used, it has been shown that the design of the developed clutch is similar to that of an induction clutch, and its characteristics correspond to the characteristics of the eddy current clutch. Therefore, the proposed new clutch with MR fluid and rotating magnetic field can be applied to stationary power transmission systems in a manner similar to an eddy current clutch.

For screening adhesive organic fertilizer particles, a Discrete Element Method (DEM) and Multi-Body Dynamics (MBD) coupling model of screening adhesive organic fertilizer particles using a flip-flow screen is established. Then, the velocity, the distribution and the trajectory of the particles during the screening process are observed. Finally, the effects of the surface energy γ , the rotational speed n , the tensional amount ∆ l and the feed rate M are investigated. The results show that the flip-flow screen could provide a high velocity for depolymerization of agglomerated particles and separation of adhesive particles from the screen panels, so adhesive organic fertilizer particles can be successfully screened by using the flip-flow screen and organic fertilizer particles in an easily absorbed range are obtained. With the increase of γ , both the flow rate and the screening efficiency decrease. With the increase of n , both first increase and then slightly decrease. With the increase of ∆ l , both increase at a low n , or slightly decrease at a high n . With the increase of M , the screening efficiency decreases, while the total flow rate first increases and then decreases. Through adjusting n , ∆ l , M , flip-flow screen can also be used to screen other adhesive particles.

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.

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]