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Purpose: The aim of the current study was to identify the efficient fiber movements for 532-nm laser prostatectomy. Materials and methods: 532-nm Lithium triborate (LBO) laser light was tested on 120 kidney tissues at three different translational speeds (TS 1, 2, and 4 mm/s) and four different rotational speeds (RS 0.5, 1.0, 1.6, and 2.1 rad/s). The applied power was 120 W at a 2-mm working distance and 60° sweeping angle. Ablation rate and dimensions of resulting ablation craters were measured. Results: Slower TSs and RSs created deeper and wider ablation craters with thinner coagulation, leading to more efficient ablation performance. Maximal ablation rate was achieved at a TS of 2 mm/s and RSs of 0.5 and 1.0 rad/s. An RS of 0.5 rad/s accompanied surface carbonization for all the TSs. Irrespective of TS, ablation rate became saturated at faster RSs than 1.0 rad/s. Faster TSs or RSs reduced tissue ablation, but increased thermal coagulation due to a shorter interaction time. Conclusions: Optimal ablation efficiency occurred at a TS of 2 mm/s and a RS of 1.0 rad/s with a thin coagulation of around 1.0 mm and no or minimal carbonization. Further studies will validate the current findings with prostate tissue and high-power levels for laser prostatectomy. [ABSTRACT FROM AUTHOR]

Purpose: This paper aims to propose a method for finding the maximum rotational speed of an inclined turntable at which the stability of the bearing oil film is maintained. Design/methodology/approach: The finite difference method was used to solve the Reynolds equation. Variation of bearing capacity of a tilted hydrostatic turret over time was determined. The combined effect of tilt and rotational speed of the turret on the oil film stability was also analyzed. Findings: When the turntable is operated at low speeds with only small angle of tilt, stability of the oil film is maintained. At lower rotational speeds, a smaller angle of tilt improves the bearing capacity and ensures stability of the oil film. Whereas, higher rotational speeds can have a considerable influence on the bearing capacity. Originality/value: The results demonstrate that the inclination or tilt of the turntable significantly affects the stability of the oil film. [ABSTRACT FROM AUTHOR]

Purpose: This paper aims to obtain the film thickness, friction torque and pumping rate and analyze the effects of roughness and surface micro-dimple texture (circular, square and equilateral triangle) on the performance of the oil seal. Design/methodology/approach: On the basis of elastohydrodynamic lubrication and the pumping mechanism of rotating shaft seal, this paper establishes a numerical model of hybrid lubrication of oil seal in sealing area. The model is coupled with fluid mechanics, rough peak contact mechanics and deformation analysis. Findings: The results show that surface texture significantly improves the lubrication properties of the oil seal. The oil seal with the square texture has the largest oil film thickness, while the equilateral triangle texture has a better effect on the pumping rate. Originality/value: To get closer to the real working environment of the oil seal, based on the surface roughness, this paper studies the effect of the texture shapes applied to the oil seal lip surface on the performance of the oil seal. The critical roughness and rotational speed values with zero pumping rate are obtained, which provides a theoretical basis for the correct selection of oil seals. [ABSTRACT FROM AUTHOR]

Screw feeders and conveyors are mainly used in industries like minerals, agriculture, chemicals, pharmaceuticals, pigments, plastics, cement, sands, and food processing for transporting and mixing the granular materials. The system looks mechanically simple but the physics of particle transport in the system is complex; problems like bridging and blockage may be observed in the operation. A comprehensive understanding is required to study the granular flow behavior in screw feeders and conveyors. Hence, this extensive review has been prepared on granular flow behavior, transportation and mixing occurring in screw feeders and conveyors, via experimental, theoretical and discrete element method (DEM) approaches. Unlabelled Image • Screw feeders and conveyors are used in a wide range of applications. • Experimental, simulation and theoretical studies of these systems are reviewed. • Simulations closely predict experimental data in most studies. • Flowability and mixing of feed material are affected by moisture content. • Particle shape and size distribution is key to understand granular flow behavior. [ABSTRACT FROM AUTHOR]

In this paper, friction stir welding process of high-density polyethylene was studied. Two tools have been chosen, concave and plate, to explore the influence of the tool on the welding quality of the material. In addition, different parameters, rotational speed and welding speed, were investigated. Tensile tests were performed after welding in order to determine the tensile strength efficiency. The greatest ultimate tensile strength was found for the plates welded by concave shoulder. [ABSTRACT FROM AUTHOR]

The Warburg observation concerning ATP generation in cancer cells is analyzed with regard to the likely involvement of H+ resonance effects on the angular velocity of the ATP synthase rotor. It is reasonable to expect that the variety of diseases associated with mitochondrial dysfunction may in part be related to the ATP synthase rate of rotation. Experimental measurements of ATP synthase rotational rates, as found in the literature, are consistent with what might be expected from the ion cyclotron resonance (ICR) frequencies of protons moving under a Lorentz force determined by the approximate surface intensity of the geomagnetic field (~26-65 ?T). One research approach proposes that applying the electronic sum of two critical multiple resonance frequencies simultaneously may serve to more closely resemble real world biochemical changes as compared to applying these frequencies sequentially. Accordingly, it is suggested that applying the sum of the two individual resonance frequencies corresponding to H+ and H3O+ has the capacity to both increase proton density as well as couple to ATP synthase rotation. Not only will this tend to stabilize the F0 rotational rate but also perhaps make it feasible to control this rate, thereby providing a new and potentially efficacious means of treating diseases connected to mitochondrial dysfunction electromagnetically. [ABSTRACT FROM AUTHOR]

The air suction engine containing sand and dust will inevitably collide with the blade and the inner and outer casing, which will affect the flight safety of the aircraft.By using explicit dynamic analysis finite element method, the rebound model of sand and dust impacting on the wall with different incident angles， incident velocities，particle size and rotating velocities was established.The rebound characteristics of sand and dust impacting on stainless steel and aluminium alloy surfaces under different conditions were studied， which provided data support for predicting the trajectory of sand and dust in particle separator.The results show that the rebound velocity increases with the increase of the incident velocity of sand and dust， and the velocity recovery coefficient keeps stable basically； under the same incident condition, the influence of aluminum alloy on the velocity recovery coefficient of sand and dust is smaller than that of stainless steel; the impact of rotational velocity and particle size of sand and dust on the impact rebound characteristics is weak and can be neglected.The sand and dust rebound angle depends only on the collision attitude and incidence angle of sand and dust. [ABSTRACT FROM AUTHOR]

Friction stir processing (FSP) is a solid-state processing technique that has proven to be an efficient surface modification process for producing aluminium matrix composites (AMCs). However, practical challenges still occur during the processing of AMCs even though extensive progress has been made in recent years. In the present study, the influence of FSP process parameters on the tensile property of Al-Ni-Fe composite has been investigated. The process parameters studied were rotational speed and advancing speed. The rotational speed varied between 600 and 1000 rpm while the advancing speed varied between 70 and 210 mm/min. The rotational speed was kept constant at each setting and the advancing speed varied. Other processing parameters were kept constant throughout the experiments. The results were compared with those of the base metal (Al). The results showed that the tensile strength decreased as the advancing speed increased. The highest tensile strength was obtained at a rotational speed of 1000 rpm and an advancing speed of 70 mm/min. [ABSTRACT FROM AUTHOR]

To improve the fertilization accuracy and distribution uniformity of nitrogen fertilizer, control method of working parameters coordinate match was proposed in this paper. Take minimum coefficient of variation as criterion, the nearly-optimal set of exposure length and rotational speed was solved based on regression models with known values of target fertilizer amount and operating speed, the interfaces were built to rapidly calculate related parameters. The static and dynamic experiments were conducted to verify the reliability and accuracy of regression models and control method; the results showed that under static conditions, the biggest difference value of fertilizer amount is 0.22g per revolution; under dynamic conditions, the deviation of fertilizer amount is less than 4.01%, the maximum deviation of rotational speed is 2.74%. Those results indicate that the control method is practical and feasible for fertilization operation. [ABSTRACT FROM AUTHOR]

Rotating electrodes can effectively improve the processing performance of micro-electrical discharge machining (micro-EDM), but there is still a lack of systematic research on the specific effects of electrode rotation and rotational speed changes. In this paper, the effects of electrode rotation and rotational speed on the discharge channel, debris stress, and debris motion in micro-EDM were analyzed theoretically. An AISI304 sheet was used as the workpiece and helical tungsten carbide alloy as the electrode. The through-hole drilling experiments of micro-EDM were carried out at low and high discharge energy and different electrode rotational speeds. In terms of processing efficiency, the effects of electrode rotation and rotational speed on material removal rate (MRR), relative tool wear ratio (RTWR), and short circuit number were analyzed. The results show that MRR increases first and then decreases, RTWR and short circuit number decrease first and then increase. In the aspect of processing precision, the impacts of electrode rotation and rotational speed on taper angle and overcut were analyzed. The results show that the electrode rotational speed has little effect on the change of the taper angle. In addition, when the electrode rotational speed is small, there is no obvious change in overcut. When the speed is too high, the overcut increases obviously and shows a trend of continuous increase. Finally, by comparing the experimental results, the optimal electrode rotational speeds of micro-EDM with two kinds of discharge energy were determined. The final experimental results also verify the correctness of the previous theoretical analysis. [ABSTRACT FROM AUTHOR]

The results of the study of the adhesion properties of recycling greases expressed in terms of the residual amount of grease that is stored on a metal plate after testing in a laboratory centrifuge are presented. It was established that the investigated samples of recycling greases in the range of the thickness of the deposition layer up to 1.0 mm, by their adhesion properties, are fully suitable for using in all types of bearings operated with a rotation speed of up to 2500 rpm. From the number of investigated grease samples, samples with a deposition layer thickness of 0.1 mm o have evidence of fairly high values of the rotational speed when the threshold value of the residual amount of grease is reached. [ABSTRACT FROM AUTHOR]

This paper reports the design, fabrication, and performance of a novel rotational energy harvester, utilizing multiple magnetic actuators and piezoelectric beams for the maximum performance in a wide range of rotational speeds. The harvester can be used in different rotational applications with low or high rotational speed and produce high output. Thin lead–zirconium–titanate (PZT) piezoelectric beams were fixed on the axis of a nonmoving wheel. One end of the beams was fixed to the center axis of the stationary wheel, while the other end hung free. Small magnets were bonded on each of the piezoelectric beams’ free ends and on a concentric wheel, fixed to a working shaft. As the working shaft drove the dynamic wheel, the magnets on the moving surface attracted the magnets on the piezoelectric beams, causing the beams to be plucked into vibration as the magnets passed by one another. The device was tested at six different rotational speeds from 180 to 500 r/min, with two different layouts, single and double plucking magnets. There will be potentials to increase up to six plucking magnets and four piezoelectric beams in this design for an increased performance. Voltage output versus time graphs were analyzed for each speed and setup. It was determined that increasing the number of plucking magnets and rotational speed was the most effective ways to increase the beam vibration and maximize the energy harvester’s performance. This is the most effective approach to increase the performance of the energy harvester in the applications that require lower speeds. The least effective case was the low speed, single magnet design, where the beam vibrated little and approximately half of the energy harvester’s time was idle time, minimizing the power harvested. [ABSTRACT FROM AUTHOR]

Aiming at the problem of bearing characteristics of deep and shallow hydrostatic bearings, the oil film pressure field and temperature field of hydrostatic bearings were simulated and analyzed. Taking the hydraulic and hydrostatic bearings commonly used in the ultra-high speed grinding motorized spindle system as the research object, the three-dimensional finite element model of the oil film of the hydrodynamic and hydrostatic bearings was established and meshed, and then the mesh quality was evaluated. The oil film pressure and temperature distribution of deep and shallow cavity hydrodynamic and hydrostatic bearings under different rotational speed and eccentricity were calculated by using dynamic mesh technology, which can be used to change the eccentricity of the oil film. Distribution of oil film pressure and temperature in shallow chamber hydrodynamic and hydrostatic bearings was analyzed. The influence of rotational speed and eccentricity on bearing capacity and the oil film temperature rise of hydrodynamic bearing was studied. The results indicate that in the operation of deep and shallow chamber hydrodynamic and hydrostatic bearings, with the increase of rotational speed and eccentricity, the bearing capacity and temperature rise of the oil film also increase, and the influence of rotational speed on the temperature rise of the oil film is greater than that of eccentricity. [ABSTRACT FROM AUTHOR]

Small hydropower systems are the best solution for electromechanical components through the use of pump operating at inverse conditions as turbine for power generation in rural settlements of under developed countries especially since its construction and maintenance is cheap. This study investigates the effects of flow rate and internal flow characterization of a model centrifugal pump operating at a rotational speed of n = 1400 rpm with 4 main blades and 4 splitters at a head of 18 (m) and flow of 12.5 (m³/h). The experiment and numerical calculations were performed, and pressure and velocity were analysed based on the results obtained. According to the results obtained, velocity increased by movement of flow through the flow passage. As the discharge increased, head decreased but the power required to run the pump increased. Centrifugal pump can perform in reverse mode as a hydro turbine devoid of any modification on mechanical components with a maximum efficiency of 62.07% recorded at Q = 20 m³/h. The study helps to recognize the numerical flow characterization and serves as a supporting document to provide vital information on centrifugal pumps to other studies. [ABSTRACT FROM AUTHOR]

• The scale effect has obvious influence on the hydrodynamic forces of CRAP. • The thrust of CRAP in model scale is smaller than that of CP at design condition. • The equal thrust points at which CRAP generates the same thrust with CP are searched through. • The delivered power of CRAP having the optimal matching rotational speeds is obviously smaller than that of CP. The propulsive efficiency maximization of contra-rotating azimuth propulsor (CRAP) at model scale is investigated through searching the optimal matching rotational speeds of the forward propeller (FP) and rear propeller (RP) of CRAP based on the potential-based panel method. The hydrodynamic performance of CRAP with changing rotational speeds (FP and RP may have different rotational speeds) are calculated. When the inflow velocity is certain, the cubic spline interpolation method is used to get the equal thrust points at which CRAP has the same thrust with the corresponding conventional propeller (CP). Then, the delivered powers at these equal thrust points are further obtained through cubic spline interpolation method. The rotational speeds of FP and RP at the equal thrust point corresponding to the minimal delivered power are the optimal matching rotational speeds of CRAP. The optimal matching calculations are carried out at different inflow velocities. The results of the optimal matching investigation show that CRAP has the lowest delivered powers when FP and RP have the optimal matching rotational speeds and that the energy saving level decreases with the increase of inflow velocity. The optimal matching rotational speed ratio decreases with the increase of inflow velocity. In general, the delivered powers of CRAP having optimal matching rotational speeds at different inflow velocities are obviously smaller than those of CP. [ABSTRACT FROM AUTHOR]

This paper presents a regression model for prediction of idler rotational resistance on belt conveyor. The advantage of the regression model is that it is created according to the real experimental measurement. Besides, the predicted model corresponds with real operational parameters, such as radial force, rotational speed and measurements, conducted via using a laboratory test facility; several criteria have been used to verify the presented regression model. Finally, by analyzing the regression model combined with influence of radical force and rotational resistance on idler rotational resistance, this paper presents an operable control ideal to achieve energy-saving. [ABSTRACT FROM AUTHOR]

Accurate rotational speed determination for rotary machines tends to be allocated high priority in technical applications. In some cases, it is not easy to measure shaft speed directly. Vibration diagnostic tools can offer an alternative solution to the problem posed by direct rotational speed measurement. Using calculated spectra and cepstra can help to determine the rotational speed easily and accurately. This paper examines the comparison of the spectrum and cepstrum based methods in terms of their applicable ranges and rotational speed estimation accuracy. Most papers which present similar comparisons state that the speed of rotary machines can be determined better with cepstrum calculation. However, this argument does not entirely stand up to scrutiny. This paper explains how to calculate the possible speed estimation error which arises out of the resolution of the discrete output data produced by the methodologies. The novel hybrid speed estimation logic uses these equations to decide which method results in the most accurate output. Numerous vibration measurements were made to test the usability of this hybrid method. It was successfully tested on electromotive drive trains, as well as spark- and compression-ignition internal combustion engines with different cylinder numbers and arrangements. [ABSTRACT FROM AUTHOR]

Abstract An optimized thin-film method for coating on a horizontal rotating cylinder is presented in this paper. The drop-casting technique is used to obtain uniform thin-film coating up to the micro/nano scale. To cover the entire surface, the cylinder rotates about its own axis and the needle applicator moves along it. The thin-film-coated cylinder can be further used as a roller mold in roll-to-roll imprinting after the photolithography process. A supportive theoretical analysis of the drop-casting technique also is presented herein. The theoretical model includes an evolution equation based on lubrication theory and the physics of the needle applicator for the particular experimental setup. The circumstances under which the uniform thin film is generated on a rotating cylinder are investigated for different concentrations of material in appropriate parameter ranges. Additionally, the results of theoretical and experimental investigations are analyzed for the purposes of a comprehensive summary of uniform thin-film coating. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Highlights • The extended wear model developed based on the Archard wear theory is effective to describe the wear behavior considering the time-varying conditions of contact forces and sliding distances between the balls and the screw/nut raceways for ball screw mechanism (BSM). • The developed methods are effective to calculate contact forces and sliding distances between the balls and screw/nut raceways from the time-varying loading and rotational speed of BSM for prediction of the wear of BSM. • The accuracy degradation analysis is effective to predict the positioning accuracy error/wear depth from the time-varying loading and rotational speed for BSM. • The random wear test scheme of BSM is designed and established under time-varying working conditions. Abstract Ball screw mechanism (BSM) plays a key role to transmit motion and power in a machine tool. The accuracy of the machine tool is greatly influenced by the accuracy of the BSM. Since accuracy degradation of BSM is primarily due to wear, the wear behavior of BSM is studied considering the time-varying motion and loading working conditions. A new wear prediction model of BSM is introduced in this research considering complex working conditions. Because BSM is subject to dynamic fluctuations of rotational speed and loading in the operation process, a loading model is established to describe the dynamic contact force between the ball and the raceway, and a motion model is developed to describe the dynamic sliding and rolling behaviors between the ball and the raceway. The degradation of BSM accuracy is analyzed considering time-varying motion and loading working conditions. Experiments have also been designed and conducted to demonstrate the effectiveness of the accuracy degradation analysis for BSM. [ABSTRACT FROM AUTHOR]

Abstract The properties and microstructure of friction stir processed AA 7075-T651 (Al-Zn-Mg-Cu) Aluminium alloy were studied using various tool designs. Trials were conducted on AA 5005-H34 with the aim of determining the most suitable FSP tool design out of the considered three different pin designs. Fully recrystallised fine microstructure and a defect free processed zone was achieved through the use of some of the FSP pin designs. For FSP 5005-H34 aluminium alloy substantial grain refinement was detected. The initial 192 µm pancake-like microstructure in the AA 5005-H34 base material was refined to 10–20 µm in the processed regions. Similarly, the grain size of around 50 µm in the base material was decreased to 4–10 µm in the processed regions of the FSP of 7075-T651 aluminium alloy. The traverse speed has a greater influence on the microhardness and mechanical properties, compared to the tool rotational speed. Microhardness and mechanical properties were improved as the traverse speed increased, due to the reduction in the precipitate-free zones at the grain boundaries. [ABSTRACT FROM AUTHOR]

Abstract Pressure fluctuations in double-suction centrifugal pumps are greatly affected by the flow rate and rotational speed. An experimental investigation was carried out to determine effects of the flow rate and rotational speed for optimizing the hydraulic design and realizing stable operation. Pressure fluctuation signals were obtained at five measurement points along the suction chamber and four measurement points along the discharge chamber by means of pressure transmitters. The flow rates ranged from 0% to 150% of the design flow rate, and the rotational speed was reduced to 850 rpm from the rated speed of 1450 rpm. Results show that the third harmonic of rotational frequency is detected as the dominant frequency in the upper part of the suction chamber at low flow rates. At zero flow rate, the pressure fluctuations increase by 200% above that at the design flow rate. The pressure fluctuations decrease by 50% as the speed is reduced from the rated speed of 1450 rpm to 1250 rpm. At 850 rpm, the pressure fluctuations at partial flow rates are larger than those at higher rotational speeds, and the maximum efficiency is 5% less than that at the rated speed of 1450 rpm. Highlights • The third harmonic of rotational frequency is detected in suction chamber. • Pressure fluctuations increase by 200% at zero flow rate compared with design flow rate. • Pressure fluctuations decrease by 50% at 1250 rpm compared with rated speed (1450 rpm). • Lower rotational speed (850 rpm) results in the raise of pressure fluctuations. [ABSTRACT FROM AUTHOR]

The effect of threshing machines on corn, Cadiz cultivar, was studied based on some technical indicators. Two types of machines (Local Corn Sheller 1 - LCS-Irs1 and Local Corn Sheller 2 - LCS-Irs2) were tested under three revolution of threshing cylinder 200, 300 and 400 rpm and three ranges of grain moistures of 16%, 18% and 20%. The experiments were carried out in a factorial experiment under complete randomized design with three replications. The results showed that LCS-Irs1 machine was significantly better than LCS-Irs2 machine in all studied conditions. The results showed a sheller productivity of 1.159 and 1.118 t.h-1, power consumption of 11.142 and 11.913 kW, shelling efficiency of 81.753% and 80.953%, unshelled grains of 3.434 and 3.884%, loose grains at kernel outlet of 3.821 and 4.723%, grains damage of 1.994 and 2.225% and grain cleanliness of 89.694 and 89.170% for LCS-Irs1 and LCS-Irs2 machines, respectively. The rotational speed of 200 rpm was significantly superior to the other two levels of 300 and 400 rpm in all studied conditions, while the moisture content of grain at range of 16% was significantly superior to the other ranges of 18% and 20% in all studied conditions. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A novel approach for real-time estimation of insoluble solids content and glucose. • Cost effective model development using mixing torque for hydrolysis monitoring. • 90% reduction in mixing torque during the first 12 h. • Rotational speeds of 50–100 rpm for 45% solids are recommended. • Fed-batch ratio of 44:22:17:17% yielded higher glucose conversions. Abstract The study describes a novel method using instantaneous mixing torque and rotational speed to estimate insoluble solids and glucose concentrations during enzymatic hydrolysis of biomass. This method is cost-effective for real-time monitoring and control of enzymatic hydrolysis and potentially scalable. The model was developed using biomass slurries at three solids loading (20, 30 and 45%) at various rotational speeds from 50 to 400 rpm. The results showed a significant drop in mixing torque at 12 h with high solids loading. Maximum glucose concentration (205 g/l) during hydrolysis was achieved at 45% solids loading. Insoluble solids and glucose concentration as a function of torque and rotational speeds were modeled using a modified Herschell-Bulkley model. The model describes the experimental observations with high fidelity (R2 = 0.84) and can be used for real time monitoring of many multiphase reaction systems as enzymatic hydrolysis of lignocellulosic biomass and dry grind corn ethanol processes. [ABSTRACT FROM AUTHOR]

In the present study, the effect of the tool travel and rotational speed on structural properties and wear resistance of 6061Al/SiC surface composites produced via friction stir processing (FSP) has been investigated. It was found that when the rotational speed was increased from 630 to 2000 rpm or travel speed was reduced from 150 mm/min to 30 mm/min, the wear resistance improved. The enhancement of wear resistance was attributed to the desirable distribution of SiC particles in the base metal. Additionally, the obtained data indicate that a significant change in the reduction of the average grain size in the stir zone (SZ) is happened by increasing the rotational speed and decreasing the travel speed. [ABSTRACT FROM AUTHOR]

Highlights • A facile synthetic route to copper sulfide in continuous Couette-Taylor reactor. • Morphology control of copper sulfide by level of supersaturation. • Level of supersaturation could be effectively regulated by rotational speed. Abstract In this report, a Couette-Taylor (CT) reactor was applied as an effective continuous process for synthesizing copper sulfide nanoparticles. The rotational speed, mean residence time (MRT), and concentration of the feed solution were important control factors on the morphology and size control of the nanoparticles. Increasing the rotational speed from 80 rpm to 90 rpm changed the morphology of the synthesized nanoparticles from nanofibers to hexagonal nanoplates. Only Cu 7 S 4 nanofibers were obtained in the batch reactor. Through various comparative experiments, we found that MRT and the feed solution concentration affect monomer concentration in the CT reactor, thus controlling the morphology and size of the nanoparticles. [ABSTRACT FROM AUTHOR]

Abstract In this work, magnetron sputtering deposition facility was performed to fabricate TiC/graphite-like carbon (denoted as GLC) composite films. The microstructure and element composition of the as-fabricated TiC/GLC composite films were analyzed by field emission scanning electron microscopy, high-resolution transmission electron microscopy, Raman spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Moreover, the influence of rotational speeds of specimen holder on microstructure, mechanical, and electrical properties of the as-prepared TiC/GLC composite films were systemically investigated. Results indicate that the microstructures of TiC/GLC composite films experience the transition from layered growth pattern to columnar growth pattern with increasing rotational speed. The transmission electron microscope characterizations show that multilayered microstructure was self-organized in the TiC/GLC composite film deposited at rotational speed of 5°/s. The TiC crystallite embedded in carbon networks composite structure dominates the films with other rotational speeds. The TiC/GLC film with multilayered structure has lower internal stress and higher adhesion to the substrate compared to composite structure. The mechanical and electrical measurement results demonstrate that the nano-hardness and conductivity are enhanced owing to formation of high content of hard and conductive TiC phase embed in the carbon networks nanostructure in TiC/GLC composite films. Meanwhile, the growth mechanisms of TiC/GLC composite films at different rotational speeds are also proposed. The excellently electrical and mechanical properties indicate that the GLC/TiC composite film possesses widespread potential as transducers for biosensors in biology and carbonaceous electrode materials. Graphical abstract Unlabelled Image Highlights • Influence of rotational speed on microstructure and properties of TiC/GLC films was discussed. • Multilayered and composite TiC/GLC films were obtained by adjusting rotational speed. • GLC/TiC films exhibited excellent mechanical and electrical properties. • The GLC/TiC film possesses potential as transducers and carbonaceous electrode materials. [ABSTRACT FROM AUTHOR]

Abstract Bird strike represents a major hazard to civil aviation. In this paper, impact damage under high velocity is numerically investigated by means of non-linear explicit finite element analysis. We mainly focus the influence of rotational speeds on damage modes and energy variations of bird impact on a circular laminated plate. The Smoothed Particle Hydrodynamics method and an equation of state were employed for the bird projectile. A Continuum Damage Mechanics approach has been applied to simulate failure initiation and damage evolution in unidirectional composite laminates. Hashin's failure initiation criteria have been employed to be able to distinct lamina failure modes. Two damage regimes are identified with respect to the rotational speeds, i.e. impact-dominated damage and rotation-dominated damage. A threshold rotational speed exists for the rotating thin plate in terms of damage regimes. The results can serve as design guidelines in future full-scale or part-scale study of rotating laminated structures. [ABSTRACT FROM AUTHOR]

With the rapid development of China's undefined economy and the urgent need of underground space engineering, the localisation of road header, especially the cutting tool of road header, is becoming more and more important. Disk cuter is the main tool of hard rock tunnelling machine. Its rock breaking efficiency and service life are directly related to the progress and cost of the project. Based on the contact force characteristics and motion law of disc cutter, a three-dimensional finite element analysis model for the driving process of disc hob is established by using Abaqus. On the basis of friction characteristics, the stress analysis of disc cutter in tunnelling process is carried out. The influence of relevant tool parameters on rock breaking efficiency is obtained by numerical simulation, and the distribution law of stress field in rock breaking process of disc cutter is obtained. And the influence of different penetration and rotation speed on the stress distribution of cutter ring. It is of great significance to analyse the stress field of TBM(Tunnel Boring Machine) disc hob to maximise the tunnelling benefit. [ABSTRACT FROM AUTHOR]

Highlights • An experimental investigation of a novel 15 kW class HCR was performed. • Heat generation rate and thermal efficiency maximally reached 48.15 MJ/h and 82.18%. • Increasing rotation speed and pump pressure resulted in higher thermal performance. • Increasing water temperature resulted in lower thermal performance. Abstract The hydrodynamic cavitation technique has been widely considered to have great potential for many environmental, chemical, and biological industrial-scale applications. This paper presents an experimental investigation of the thermal performance, i.e. , heat generation rate and thermal efficiency of a novel, advanced, rotational 15 kW class hydrodynamic cavitation reactor (HCR). The cavitation generation mechanism of the HCR was analyzed according to flow visualization. The thermal performance was tested in 20 experiments with various rotational speeds of the rotor (2700, 3000, 3300, and 3600 rpm) and pump pressure settings (0.0, 0.5, 0.7, 1.0, and 1.5 bar gauge pressure) without controlling the flow rate. The HCR achieved a maximum heat generation rate of 48.15 MJ/h (i.e. , 13.375 kW) and a maximum thermal efficiency of 82.18%. To evaluate the independent effects of the operational conditions, the thermal performance was also evaluated under various flow rates (6, 8, and 10 L/min), pump pressure settings (0.5, 0.8, 1.1, and 1.4 bar), and inlet water temperatures (15, 25, 35, and 45 °C). The results showed that increasing the rotational speed, flow rate, and pump pressure setting gave rise to higher heat generation rate and thermal efficiency of the HCR. Moreover, the thermal performance decreased with increasing water temperature. Compared with the conventional and advanced rotational HCRs introduced in previous research, the HCR in this study provided more outstanding thermal performance and stable operational state and has great development potential for various large-scale applications. [ABSTRACT FROM AUTHOR]

In this study, the effect of tool rotational speed on mechanical properties of AA 6082-T6 aluminum alloy was investigated. Different welded joints were produced by using four rotational speed (500, 710, 1000 and 1400 rpm) and constant welding speed at 80 mm/min. Mechanical properties of the welded joints were evaluated by hardness measurement on the transverse section and tensile testing. The experimental results show that the tool rotational speed has a significant effect on weld mechanical properties of joints. [ABSTRACT FROM AUTHOR]

Abstract The quality of YAG:Ce phosphors will influence the luminescent performance of white LEDs devices. Therefore, in this study, we attempted to synthesis high quality YAG:Ce phosphors using coprecipitation method. YAG:Ce precursors were synthesized through coprecipitation at different rotational speeds of an electromagnetic stirrer and then heated at different calcination temperatures ranging from 900 to 1300 °C. X-ray diffraction analysis revealed that phase-pure phosphors could be obtained from the precursors synthesized at 400 rpm and then calcined at 1300 °C. The emission intensity of Ce-doped YAG phosphor increased with the calcination temperature, owing to the higher crystallinity of the YAG phase. Moreover, at the same calcination temperature from 900 to 1300 °C, the maximum fluorescence intensity at approximately 540 nm of the YAG:Ce nanopowders synthesized at 400 rpm increased three to five times that of the YAG:Ce nanopowders synthesized at 200 rpm. The optimal luminescence performance of the YAG:Ce nanopowders was obtained at 400 rpm and at a calcination temperature of 1300 °C. The results of luminescence performance indicated YAG:Ce nanopowders has a great potential for development of white LEDs devices. Graphical abstract Unlabelled Image Highlights • YAG:Ce nano-powders were prepared using coprecipitation. • Photo-luminescent spectra of YAG:Ce was analyzed by a fluorescent spectrophotometer. • Effect of heat temperature on fluorescent intensity was discussed. • Fluorescent intensity of YAG:Ce affected by electromagnetics stirrer's rotational speed was validated. [ABSTRACT FROM AUTHOR]

Since tillage is one of the processes requiring high power, energy consumption in field operations is of great concern to farmers and researchers. A combined tillage tool has been recognized as one measure to reduce the power requirements in field preparation. In this research work, a combined tillage tool consisting of a subsoiler and rotary harrow (joined using four different linkage configurations) were tested under actual field conditions. The test parameters consisted of: tillage tools (combined tillage tool with four different linkages, a sole subsoiler and a sole rotary harrow), forward speeds (1.79, 2.67, and 3.33 km h −1 ), and rotational speeds of the rotor (299 and 526 rpm). The experiment site was located at 14.00 °S and 99.58 °E having a clay soil type and bulk density in the range 1.5–1.7 g cm -3 with an average water content of 16.6% (db). The results indicated that the combined tillage tool was able to reduce the draft for subsoiling by 4.4–11.3% depending on the linkage configuration compared with the same sole subsoiler used alone. There were significant effects of the rotational speed of the rotary harrow and the forward speed on the drawbar power, the PTO power, and the total power. The combined tillage tool with linkage IV consumed the least total power. The combined tillage tool with linkages I to IV used less total power by 13.7, 12.2, 10.5, and 15.3%, respectively, compared with the combined power required by the sole subsoiler and sole rotary harrow working separately. [ABSTRACT FROM AUTHOR]

This work aimed to investigate the effect of the rotational speed of drilling pipe on casing wear using a laboratory-scale, pin-on-disc machine. The material used for the cylindrical pin specimens was type G105 steel, and the disc was made from type N80 carbon steel. Tests were conducted under simulated drilling fluid conditions. The wear rate, surface features, surface profile of the wear product films, composition of the wear product, and variations in drilling fluid temperature under different rotational speeds of drilling pipe were analyzed. Wear rate varied with increasing rotational speed of drilling pipe, but not in a linear manner. The reasons for the wear behaviour were explained in terms of a combination of abrasive wear, erosive wear, and corrosive wear. The activity of the Cl- in the drilling fluid could influence the formation and properties of the protective film on the casing surface. The results of this study could serve as a reference for drilling engineers, product suppliers, and manufacturers in related industries in reducing casing wear. [ABSTRACT FROM AUTHOR]

A rotational sponge (RS) reactor was proposed as an alternative sewage treatment process. Prior to the application of an RS reactor for sewage treatment, this study evaluated reactor performance with regard to organic removal, nitrification, and nitrogen removal and sought to optimize the rotational speed and hydraulic retention time (HRT) of the system. RS reactor obtained highest COD removal, nitrification, and nitrogen removal efficiencies of 91%, 97%, and 65%, respectively. For the optimization, response surface methodology (RSM) was employed and optimum conditions of rotational speed and HRT were 18 rounds per hour and 4.8 h, respectively. COD removal, nitrification, and nitrogen removal efficiencies at the optimum conditions were 85%, 85%, and 65%, respectively. Corresponding removal rates at optimum conditions were 1.6 kg-COD m −3 d −1 , 0.3 kg-NH 4 + -N m −3 d −1 , and 0.12 kg-N m −3 d −1 . Microbial community analysis revealed an abundance of nitrifying and denitrifying bacteria in the reactor, which contributed to nitrification and nitrogen removal. [ABSTRACT FROM AUTHOR]

This study considers the design of surface‐mounted permanent magnet electrical machines for high‐speed applications and proposes a methodology to determine the maximum achievable power density. Power density is usually improved by increasing rotational speed. At high speed, a mechanical retaining system for the rotor magnets must be considered. As the speed increases, the thickness of the retaining sleeve becomes larger, reducing torque capability. There will be an optimal speed at which the output power will be maximised. Both structural and electromagnetic design must be considered simultaneously to properly address this design problem. To simplify the design procedure, static finite‐element simulations are used for the electromagnetic analysis and analytical formulae are employed for retaining sleeve sizing. The procedure is aided by multi‐objective optimisation algorithms. A case study based on the specification of an aeronautical actuator is presented. The performances that can be obtained using different iron cores, high‐grade silicon steel, and cobalt iron steel are compared. Finally, results obtained from transient finite‐element electromagnetic and structural analysis are presented to validate the feasibility of the proposed procedure. [ABSTRACT FROM AUTHOR]

Although rotating dryers with flights have been extensively used in industrial applications, there is still a lack of universality in the literature models to estimate their design loading. The aim of the present paper was to study the design loading of a flighted rotating drum and its dependency on rotational speed. The use of high rotational speeds is a novelty of this paper, to operate at peripheral speeds like the ones in industrial equipment. The effect of the rotational speed on the last unloading flight was also studied. The results showed the limitations of the geometric models to predict the design loading. A new model was proposed to predict the Froude number for design-loaded equipment as a function of the drum filling degree. The results predicted were very close to the experimental data. [ABSTRACT FROM AUTHOR]

Underground coal mining leads to fracture and movement in the overburden and the occurrence of weighting events in stopes. There are certain key strata that play an important role in controlling overburden movements. After the key stratum breaking, the fractured blocks would form the voussoir beam structure. The rotational speed of the voussoir beam structures directly affects the intensity of the ground pressures in a stope. In this study, a mechanical model was constructed to describe the rotational motions of the voussoir beam structures formed by the key strata based on elastomechanical theories. The angular velocity equations for the rotational motions of the voussoir beam structures in the key strata were obtained. Moreover, the manner in which loads and block lengths affect the angular velocity was investigated. The rotational angular velocity of the fractured blocks was found to increase with greater overlying loads on the key strata and shorter block lengths. The main roof has a major influence on strata behavior in stopes, and increases in the angular velocity of its voussoir beam structures increase roof subsidence rates, the yield of powered supports within each coal mining cycle, and the intensity of weighting events in stopes. If one or more of the voussoir beam structures formed by key strata above the main roof have greater rotational speeds than those of their underlying key strata, additional loads are applied to the latter, causing their rotational speeds to increase. If this application of loads is transmitted to the main roof, there is a strong possibility that highly intense weighting events will occur as a result of increases in the rotational speed of the main roof's voussoir beam structures. The research result provided a rational explanation for the significant differences in the weighting events of the No. 52304 working face in the Daliuta Coal Mine, which was covered by thick versus thin Aeolian sands. The results may be greatly significant in evaluating the intensity of weighting events, predicting the scope in which the strata movement affects the weighting events in stopes and determining a reasonable powered support capacity. [ABSTRACT FROM AUTHOR]

This study is concerned with the unified analytical solution of rotor strength for the segmented permanent magnet (PM) rotor retained by the carbon‐fibre sleeve and non‐magnetic alloy sleeve in high‐speed surface‐mounted permanent magnet synchronous machine. Considering the influence of different densities and coefficients of thermal expansion of PMs and pole fillers on rotor stress, the analytical solution for rotor strength was proposed based on displacement method and stress potential method in polar coordinate. The proposed analytical solution was validated by the finite‐element method (FEM) and experiment, respectively, and the influences of rotational speed, retaining sleeve thickness and interference fit between the retaining sleeve and PMs on rotor strength were further investigated based on the analytical solution proposed. It is shown that the results calculated by the proposed analytical solution and the FEM are in good agreement with each other, and the analytical solution can accurately predict the stress distributions of the segmented PM rotor retained by the carbon‐fibre sleeve and non‐magnetic alloy sleeve. The difference in density and coefficient of thermal expansion between PM and pole filler, rotational speed and operating temperature have great effects on rotor strength. [ABSTRACT FROM AUTHOR]

The use of different crushers to obtain the required size of the stone material. This work presents experimental studies of the characteristics of a crusher with a complex movement of working organs. The objectives of the study are, a sieve analysis of the obtained product (crushed stone) and the determination of the optimal speed of the working bodies (rolls) to obtain high-quality cubic shape crushed stone. In the experiment, the raw material is fed into the working space (into the crushing chamber) through the hopper and moves by a flat flow between the rollers. The edges of the rolls roll symmetrically from two sides to the flow of material, approaching in the area of the crushing zone and diverging in the region of the unloading zone. The authors determined the optimal rolls for obtaining high-quality cubiform crushed stone (over 80%). As a result, of the research, it was established that the grain composition of the fraction is within the standard of the Republic of Kazakhstan 1225-2003 t.3 - is obtained cubiform crushed stone, with an rotational speed of rolls of 100-120 rpm. [ABSTRACT FROM AUTHOR]

A mixing device with swinging (rotationally reciprocating) movement of the actuating element, the advantage of which, compared to the classical units, is that it produces a higher mixing rate, is investigated. In designing the new devices, it is necessary to know the moment of resistance of the liquid medium and the power consumed in the mixing process. It is shown that, in the general case, the actuating element is affected by both the linear and quadratic resistance of the fluid and formulas are found for determining the moment of resistance and the power. As a result of the study it is found that the Reynolds number grows and the power consumption increases as the oscillation angle and rotational speed of the actuating elements increase. [ABSTRACT FROM AUTHOR]

In this study, an organic Rankine cycle with R134a as the working fluid was developed, and a variable-rotational-speed dual expander was used. To improve the cycle performance at various heat source temperatures, the expander was operated in single-expander (SE) and dual-expander (DE) modes at different rotational speeds. Although the electrical output became unstable when the superheat degree was insufficient, it improved when the heat source temperature increased and the expander rotational speed reduced. At a low heat transfer rate, reducing the expander rotational speed effectively decreased the refrigerant mass flow rate and increased the evaporation pressure. In DE mode, the isentropic efficiency ranged from 55.8% to 65.8%. A performance map was created to divide the operating region into three subregions depending on heat transfer rate: 10–17 kW in SE mode at 900 rpm, 18–26 kW in SE mode at 1350 rpm, and ≥27 kW in DE mode at 900 rpm. During a dynamic test conducted at a low heat transfer rate, when the operating mode was switched to SE mode at 900 rpm, the cycle performance was 66% and 108% higher than that in SE mode at 1800 rpm and that in DE mode at 900 rpm, respectively. • A 2-kW ORC with variable rotational speed and dual expanders has been constructed. • Evaporation pressure and flow rate of refrigerant affected by expander rotational speed. • A performance map was created to divide the operating region into three subregions. • Cycle performance of 900 rpm was 66% higher than that of 1800 rpm at low heat transfer rate. • DE mode and high rotational speed suitably operated at high heat transfer rate. [ABSTRACT FROM AUTHOR]

This Letter presents an amplitude modulation method of the rotating‐based mechanical antenna that does not require the change in the rotational speed of the permanently polarised material as in frequency modulation, hence overcoming the mechanical design challenges. A mechanical‐based modulator is designed to control the attenuation of the radiation field in specific polarisation direction, and the signal reception in different polarisation directions is realised by using two‐axis orthogonal coils. The underlying physics is discussed and simulated using the basic electromagnetic theory, the design of transmitters is described, and a prototype is built to verify the effectiveness of the modulation method. [ABSTRACT FROM AUTHOR]

A three-dimensional model was developed based on computational fluid dynamics (CFD) to study the visco-plastic material flow during friction stir welding of AA6061 aluminum alloy and Al-Mg 2 Si composite dissimilar joint. To model the dissimilar joint, the volume of fluid (VOF) method was used. The volumetric equation was defined for the heat which generated through the viscous dissipation. The model was investigated for three rotational speeds of 720, 920 and 1120 rpm. The nugget shape was in good agreement with the corresponding experimental results. The results showed that maximum velocity and strain rate occurred at the top surface of the workpiece and outer edge of the shoulder. Also, peak temperature was obtained at the advancing side. The strain rate at the advancing side and the retreating side was about 975s −1 and 926s −1 , respectively. In a region of the stir zone where material mixing is dominant, the volume fraction of the AA6061 aluminum alloy is 0.4–0.8. [ABSTRACT FROM AUTHOR]

A model is developed to obtain the friction stir welding (FSW) induced stress in structures, which includes the welding process and the cooling process. The characteristics of the welding stress are presented in the analytical results. A detailed numerical simulation is also performed to verify the effectiveness of the proposed model. Numerical results of the welding stress agree well with the welding stress obtained from the analytical model. Then, the effects of process parameters of FSW on the welding stress are studied by using the analytical model. The process parameters involve the depression depth of the welding tool, the rotational speed, and the advancing speed. The calculated results show that the radial stress in the welded structure decreases with the increase of the depression depth. Larger tensile stress appears beneath the tool shoulder with the increase of the rotational speed. Higher advancing speed introduces lower tensile stress in the welded structure. [ABSTRACT FROM AUTHOR]

The energy saving performance of contra-rotating azimuth propulsor (CRAP) is investigated based on low order potential-based panel method. The hydrodynamic interactions among the forward propeller (FP), rear propeller (RP) and the pod unit (PU) which includes the pod body and the strut are considered through induced velocities which are obtained by panel method. In order to have a better understanding about the energy saving performance of CRAP, the hydrodynamic performance of a conventional propeller (CP) supplying the same thrust with CRAP at design condition is also calculated. At design condition, CRAP has a decrease in delivered power by approximately 8% comparing with CP, and the tangential induced velocities in slipstream show that CRAP recovers the rotational energy of slipstream effectively. At off-design conditions, the rotational speed of CRAP is adjusted to supply the same thrust with CP. In general, the delivered power of CRAP is significantly smaller than that of CP, and the energy saving performance of CRAP increases with the decrease of inflow velocity. [ABSTRACT FROM AUTHOR]

Effects of adsorption isotherms, namely shape factor and maximum adsorption capacity, and rotational speed on regeneration temperature of desiccant wheel systems are investigated. Higher maximum adsorption capacity is beneficial for reducing regeneration temperature especially for deep dehumidification of single-stage systems under humid climate, while the influence is not obvious with small dehumidification capacity. Higher shape factor (=1) is recommended for dehumidification at high relative humidity, while lower shape factor is better for low relative humidity. Rotational speed in the range of 10–15 r h −1 is advised for single and two-stage systems under a wide range of working conditions for both deep and regular dehumidification applications when wheel thickness is 0.2 m and maximum adsorption capacity is 0.8 kg kg −1 . The reasons for different requirements of shape factor for regular and deep applications are discussed theoretically. Rotational speed ranges for different wheel thickness and maximum adsorption capacity are recommended. [ABSTRACT FROM AUTHOR]

The bone drilling process is indispensable in orthopaedic surgeries and treating bone breakages. It is also very important in dentistry and bone sampling operations. Bone is a very complex material and the process of drilling is very sensitive. Thus, bone drilling is one of the most important, common in the field of biomedical engineering. The bone drilling process can be promoted using automatic drilling machines and surgery-assisting robots. The problematic issue during operation is the high increase in drilling process temperature (higher than 47 °C) which leads to the so-called ‘thermal necrosis’ or cell death, and local burn in bone tissue. Furthermore, imposing higher forces to bone might yield to breaking or cracking, and consequently causes serious damages in bone. In this paper, the tool rotational speed, feed ratio and tool diameter were taken into account as process input parameters, and process temperature and thrust force were taken as output parameters. Design of experiments using response surface methodology was followed. Then, second linear governing equation was assigned to the model and its accuracy was evaluated. Later, Sobol statistical sensitivity analysis was used to ascertain the effect of process input parameters on process temperature and force. The results showed that among all effective input parameters, the tool rotational speed, feed rate and tool diameter have the highest influence respectively on process temperature and force. The behaviour of each output parameter with variation in each input parameter was further investigated. [ABSTRACT FROM PUBLISHER]

Friction Stir Spot Welding (FSSW) of AA5052-H32/HDPE/AA5052-H32 sandwich sheets is performed at six different tool rotational speeds to evaluate the optimum range. The mechanical performance, hook formation, grain size, hardness and temperature distribution are evaluated. Lap shear test, cross tension test, peel test and uni-axial tensile test are conducted. A comparative assessment has been made between the bimetallic and the sandwich sheets after FSSW. The optimum rotational speed for joining the sandwich sheet is 1800 rpm and beyond, where the joint strength and extension to failure are found to be acceptable. In hook formation, two hooks are prominently seen in the sandwich sheets, while it is only one hook in the bimetallic sheets. The hook width increases and the hook height decreases with increase in rotational speed. A mechanism has been proposed to explain such phenomenon. The peak temperature increases with increase in rotational speed and it gets reduced in sandwich sheet as compared to bimetallic. The polymer layer takes a part of the heat flux during stirring to reduce the peak temperature in sandwich system. The bimetallic joints are stronger than sandwich sheet joints showing better joint strength and extension at failure in almost all the tests. Joint hardness distribution supports such performance. Nugget pull-out and partial nugget failure are observed during joint failure of sandwich sheets. [ABSTRACT FROM AUTHOR]

The paper presents a system of differential equations that describe the processes of motion transfer in mechanisms taking into account the essential nonlinearities caused by hysteresis phenomena, dead zones, pressure limitations, etc. The computational algorithm is based on the Runge-Kutta method of the fourth order. A solution to a system of ordinary differential equations is described in the presence of essential nonlinearities. Here, at each stage of the calculation, the features of the nonlinearities that are present in the system are taken into account. The results of modeling the change in the speed of rotation of the output link and stresses in mechanical lines after a stepwise increase in the control action are given. The simulation was carried out with the help of a computer with the steps of counting H=10-4; 2*10-4s. The error did not exceed 10%. [ABSTRACT FROM AUTHOR]

This research focused on studying the influence of friction stir welding (FSW) factors - such as the type of the welding tool, the speed of the welding tool and the welding speed - on the impact toughness of the panels made of AA6061 - T6 aluminum alloy sheets with thickness of 3mm. The aluminum alloys have multiple uses in industry, but are quite difficult to be welded by fusion welding processes, including MIG welding, and laser welding. By using a milling machine, it was possible to employ the FSW process, applying four constant welding speeds (800, 1000, 1250, 1600 rpm) and three welding speeds (32, 63, 80 mm/min). Tool pins with square cylindrical and threaded tapered cylindrical profiles were used in the experimental programme. The machined samples were subjected to Charpy V notch impact test at room temperature and the results were compared to the impact energy of the base metal. The results show higher values of the impact energy when the tool pin used has square profile. [ABSTRACT FROM AUTHOR]