Blade Speed Research Articles

Implementation of Minimally Invasive Brain Tumor Resection in Rodents for High Viability Tissue Collection.

The present protocol describes a standardized paradigm for rodent brain tumor resection and tissue preservation. In clinical practice, maximal tumor resection is the standard-of-care treatment for most brain tumors. However, most currently available preclinical brain tumor models either do not include resection, or utilize surgical resection models that are time-consuming and lead to significant postoperative morbidity, mortality, or experimental variability. In addition, performing resection in rodents can be daunting for several reasons, including a lack of clinically comparable surgical tools or protocols and the absence of an established platform for standardized tissue collection. This protocol highlights the use of a multi-functional, non-ablative resection device and an integrated tissue preservation system adapted from the clinical version of the device. The device applied in the present study combines tunable suction and a cylindrical blade at the aperture to precisely probe, cut, and suction tissue. The minimally invasive resection device performs its functions via the same burr hole used for the initial tumor implantation. This approach minimizes alterations to regional anatomy during biopsy or resection surgeries and reduces the risk of significant blood loss. These factors significantly reduced the operative time (<2 min/animal), improved postoperative animal survival, lower variability in experimental groups, and result in high viability of resected tissues and cells for future analyses. This process is facilitated by a blade speed of ~1,400 cycles/min, which allows the harvesting of tissues into a sterile closed system that can be filled with a physiologic solution of choice. Given the emerging importance of studying and accurately modeling the impact of surgery, preservation and rigorous comparative analysis of regionalized tumor resection specimens, and intra-cavity-delivered therapeutics, this unique protocol will expand opportunities to explore unanswered questions about perioperative management and therapeutic discovery for brain tumor patients.

Some effects of turbine inertia on the starting performance of vertical-axis hydrokinetic turbine

Straight-bladed vertical-axis hydrokinetic turbines have a number of advantages for power extraction from river, tidal, and ocean currents. They are simple to construct, the generator does not need to be submerged, and they can have good power extraction efficiency. Among their potential disadvantages is that when the load is lost, or when they start with no load, they can reach high instantaneous blade speeds before returning to a “steady” runaway speed. These high speeds can cause high loads on the blades and must, therefore, be fully understood. This paper describes a computational investigation of the effect of inertia as a turbine starts from rest with no load and reaches runaway. Turbine inertia is modified by altering the blade density while the turbine geometry is not altered. At the minimum inertia, the added mass contributes significantly to the dynamics, and the highest overshoot occurs in blade speed. Increasing inertia damps the peak but slows the acceleration. The added mass depends on blade mass but is constant for the whole starting sequence and is independent of water speed. The results give guidance for the design of turbines to balance the minimization of the overshoot and starting time.

Simulation and Experiment of Spiral Soil Separation Mechanism of Compound Planter Based on Discrete Element Method (DEM)

In order to solve the problems of blocking the drainage ditch and reducing the soil flatness caused by soil accumulation when using compound planter with plowshare to ditch, a spiral soil separation mechanism (SSSM) is designed. The SSSM is analyzed. In order to obtain the optimal parameters of the SSSM, based on the discrete element method, the multifactor test is carried out with the embedded depth, pitch, and rotation speed of the spiral blade as the test factors and the soil separation distance and uniformity as the evaluation index. The optimal parameters are the embedded depth 49 mm, pitch 331 mm, and rotation speed of the spiral blade 318 r min−1. The field experiment is carried out with these parameters, with soil separation distance 900 mm and standard deviation of soil height 7.8 mm, which is consistent with the simulation results. No blockage of drainage ditch was found, which shows that this device can effectively solve the problem. This study can provide a reference for the design of soil separation equipment using spiral soil separation device.

Numerical Simulation Of Propellant Slurry Stirring Process

Abstract Taking the mixing process of medicine slurry in kneader as the research object, the finite element analysis method was used to simulate the law and characteristics of TCM slurry flow in the mixing process. The simulation results show that the telocentric blade plays an important role in the stirring process. The scraping area of telecentric blades and the kneading area of two blades are the main kneading areas. The flow direction of slurry does not change at different speeds, and the velocity has a linear relationship with the blade speed. The axial conveying capacity is the best at the central horizontal section of the mixing kettle. When the rotational speed increases, the shear stress and viscous heat loss rate increase, and the viscosity decreases.

Experimental Verification of Wind Power Generation System Using Diode Bridge Rectifier Circuit with Wind Turbine Simulator

This paper presents Wind Power Generation System using Diode Bridge Rectifier (WPGS-DBR method). Experimental results have been obtained by Wind Turbine Simulator (WTS). The WTS emulates wind turbine behavior using a servo motor as a drive system. Mechanical torque references used to drive the motor are calculated using wind turbine data such as wing blade, wind velocity, and wind turbine rotation speed. DBR method has three-mode control for three ranges of wind speed: low, medium, and high, respectively. In low and medium mode, the control system adjusts the armature current of a generator and DC link voltage with a Vector-Controlled Inverter (VCI) to control wind turbine speed. In high mode, the control system modulates the pitch angle of the wind turbine using a pitch angle control system for controlling wind turbine rotational speed. The DBR simplifies the maintenance of WPGS while improving reliability. In addition, the DBR method costs less compared with the WPGS using a PWM converter.

Geometric Evolvement, Simulation, and Test of a Bionic Lateral PDC Reamer Bit Inspired by Capra sibirica Horn.

PDC (polycrystalline diamond compact) bit is the key equipment for drilling holes inside the rock in oil and mining industry. Inspired by the shape and structure of Capra sibirica horn, a bionic lateral PDC reamer bit with variable lateral reaming radius was developed. Side view of Capra sibirica horn was employed for fitting the horn shape curve based on picture processing method. PDC teeth were arranged on the horn shape blade imitating the transverse ridges on the horn to cut the rock material, found with only 30% utilization rate of the total teeth and load concentration of the last tooth. A bionic blade curve evolved from the Capra sibirica horn was defined with geometric method for the lateral reamer bit; the utilization rate of the teeth on the bionic blade curve was improved to 90% with uniformly distributed reaming load. Multigroup simulations were conducted with the finite element method; the effects of bit revolution speed and rotation feed speed of the bionic blade to reaming load were emphatically studied. Concrete sample was reamed indoors from 240 mm to 407 mm in diameter, and the bionic lateral PDC reamer bit was approved by the test result.

Development and Evaluation of Self-propelled Cabbage/Cauliflower Harvester

In the present study, self-propelled cabbage/cauliflower harvester was designed, developed and evaluated. The machine consisted of different components like engine, frame, shearing (cutting) unit and power transmission unit. The power transmission unit consisted of main clutch, shearing blade operating clutch, belt drive unit, chain and sprocket drive, universal joint and cutter blade assembly. The main working principle of harvester is based on shearing of crop stem against high-speed rotating blade. The power from the engine is transmitted by belt-pulley drive unit to transmission shaft on which chain and sprocket is mounted on one side and then power is transmitted to shearing blade coupling with the help of a stationary pulley and fixed socket. Average mean head diameter of the selected cabbage and cauliflower was 89.5 ± 15.24 mm and 107.5 ± 15.24 mm, respectively. Average mean stem (plant) diameter of the selected cabbage and cauliflower was 18 ± 4.85 mm and 21.5 ± 3.08 mm, respectively. The shearing force increased with increase in diameter of stem. The optimum performance of the machine was achieved when it was operated at 1.5 km/h forward speed and the shearing blade moving at speed of 147 rpm. The mean field capacity for developed prototype was observed as 0.063 ha/h and 0.053 in case of cabbage and cauliflower, respectively with field efficiency of 91.97 and 90.48 %. The average head damage was negligible (0.15 %) for both the crops. The average untrimmed percentage with developed harvester was 3.2 and 3.0% in case of cabbage and cauliflower crop, respectively. The developed machine helps to increase the field capacity in cabbage/cauliflower harvesting due to 7-times more capacity and 50% cheaper compared to traditional method of cabbage/cauliflower harvesting. At the operating condition of forward speed (1.5 km/h) and shearing blade speed (147 rpm), the machine could harvest 0.5 ha of cabbage and 0.42 ha of cauliflower farm per day of 8-h. This same task would have required between 15 labour per day if entirely done manually.

Simulation analysis and experimental validation of conveying device in uniform rrushed straw throwing and seed-sowing Machines using CFD-DEM coupled approach

• No-till farming is being increasingly used worldwide for more efficient crops. • In crop rotation, the straw of a crop can be used for the next cycle. • We developed a planter that performs even crushed straw coverage. • The coverage and planter performance are verified in simulations and implementation. • We provide the optimal parameters for even coverage and meeting operation standards. In agricultural fields with full straw retention, shredded straw tends to be thrown unevenly. To achieve uniform crushed straw throwing in dense fields of rice stubble, and high-quality straw mulching in dense fields, the conveying device of a no-till planter to perform uniform throwing of crushed straw stubble on fields and determine the device operation mechanism was analyzed. Using kinematics and dynamics analyses of particles of crushed rice straw during lifting and dispersion, a flexible-body model of rod-shaped and agglomerate-shaped crushed straw and a coupling model that included the mechanical structure of the device were developed. By integrating computational fluid dynamics and the discrete element method, the gas–solid coupling theory in numerical simulations and motion analysis of crushed straw particles was used to determine the flow field and motion characteristics under different parameters. The simulation focused on the conveying performance of different pipelines under four scenarios with varying throwing blade speed, conveying volume, pipeline diameter, and initial feeding velocity. The influence of these parameters on both the conveying device performance and their own variation was determined. Actual operations that are then compared with test results to achieve optimal operation were demonstrated. By adopting the Box-Behnken design, the throwing speed of crushed straw was set to the evaluation index a response surface test was performed on the throwing blade speed, conveying volume of crushed straw, and pipeline diameter. The optimization results showed that the predicted optimal parameters were 2300 rpm throwing blade speed, 1.4 kg/s conveying volume, and 220 mm pipeline diameter. The simulated planter achieved an optimized throwing speed of 14.6 m/s. Then, a field test verification was conducted, and the results were averaged. The planter achieved a throwing speed of 14.8 m/s with the same optimal parameters. The straw lifting and throwing device provides high conveying performance and satisfies requirements for real-time operation. This study provides a theoretical basis and supporting data for innovating seeding technologies and optimizing equipment to achieve uniform crushed straw-throwing in dense fields of rice stubble.

Thermal-Hydraulic analysis of axial gas turbine blade

A gas turbine engine service life is mainly determined by the lifespan of high-pressure turbine blades. Computational simulations are becoming increasingly important for safe design and optimized blade profile for achieving maximum efficiency. The impact of high-pressure high temperature gas on a rotor blade in motion can result various failure mechanism along the blade profile. A detailed computational analysis has been presented in this paper to investigate the effects of turbine speed and inlet conditions on the 1st stage of an axial flow high pressure gas turbine. A Finite element simulation software was used to assess the thermal hydraulics of high energy fluid flow under a variety of mass flow and temperature conditions. The developed wall shear stress under such a compressible flow domain was found to be dependent on blade speed considered in this analysis.

Optimization of the Stirring Blade Structure of the Pumping Unit Based on the Improvement of Concrete Suction Efficiency

In this paper, a discrete element method (DEM) is used to simulate the suction process of fresh concrete in the pumping system, and the influence of the stirring blade on the suction is explored. The Hertz‐Mindlin with JKR Cohesion contact model is used to establish the DEM model of fresh concrete, and the suction work is realized by an API function of DEM, and the movement of particles in the suction cylinder can be completed smoothly. The changes of the concrete flow field during the suction process are further studied, and the influence mechanism of the stirring blade on the suction process is explained. A numerical simulation scheme is designed to explore the influence of the rotation speed, installation angle, and edges distance of the stirring blade on the suction efficiency and the stirring resistance torque, and the structure of the stirring blade is optimized according to the influence law. The simulation results show that the stirring resistance torque of the optimized stirring blade is reduced without the suction efficiency of the pumping system reduced, and the stirring energy consumption of the pump suction is reduced.

Gaultherin production from gandapura (Gandapura fragantissima) using photo extractor-UV machine

Gandapura extraction process using ethanol as a polar compound has two functions, namely: deactivating the gaultherase enzyme and extracting the active compound gaultherin. This study examines the effect of extraction using UV from the concentration of ethanol in the extraction process of gandapura leaves into gaultherin on the extraction time, with a ratio of solvent and feed of 5:1, the rotational speed of the stirrer and the rotational speed of the chopper blades are 75 and 125 rpm, respectively. Drying agent is added according to the experimental variables; the independent variables includes ethanol concentrations of 85, 90, and 96%, while the extraction times are 10, 30 and 50 min, respectively. Gaultherin concentration was obtained from HPLC Alliance 2695 (Waters) analysis with Photodiode Array Detector 2996 (Waters) at a wavelength of 254 nm. The effect of UV photo extraction on the acquisition of gaultherin compounds has succeeded in deactivating the gaultherase enzyme and opening when it is penetrated with ethanol. In this study, the peak of the dominant gaultherin compound was found at the retention time of 5.8 min, and the highest area was at 90% ethanol concentration variable with an extraction time of 50 min; the area was 22.783% of the total gaultherin area.

Automatic Pneumatic Sheet Metal Feeding and Cutting Machine

Abstract: Today in the rapid competition of the industries to get the best quality of the product in the minimum required time is the main aim of industries. To get the best quality and maximum production most advanced machines are used. But there are no facts that use only the advanced machines, to maintain their performance is real requirement of the industries, also to give proper facilities to the workers with good environmental condition and to reduce their efforts is one of the objects to achieve the best quality and high production. Sheet metal is simply a metal formed into thin and flat pieces. It is one of the fundamental forms used in metal working and can be cut and bent into a variety of different shapes. Countless everyday objects are constructed of the material. Thicknesses can vary significantly, although extremely thin thicknesses are considered foil or leaf, and pieces thicker than 6 mm (0.25 in) are considered plate. Sheet metal also has applications in car bodies, airplane wings, medical tables, roofs for buildings (Architectural) and many other things. Sheet metal of iron and other materials with high magnetic permeability, also known as laminated steel cores, has applications in transformers and electric machines. There are three primary procedures in Layout. They are Parallel, Radial, and Triangulation. The major aim to our experiment is to study about pneumatic control system, study about double acting cylinder, study about the advantage of pneumatic hand operated valve and study about high speed blade. We are using scissors for simple sheet metal cutting. It is a manual method so that sheet metals are to be wasted sometimes because of mistakes happened such as wrong dimensions etc., and also even a simple cutting may take long time. We are using a pneumatic system for sheet metal cutting in an easy way. It is operated by a pneumatic hand lever of two ways control valve. Control valve is operated by a compressor. Keywords: Pneumatic, Automation, Sheet Metal, Pneumatic, Valve, Cutting Machine

Modelling and Analysis of a Solid Waste Composter for Urban Houses

Disposal of waste is an important issue faced by sanitation agencies, especially in India, where the volume of waste generated has been increasing rapidly over the last few years. According to the Ministry of Housing and Urban Affairs, as of January 2020, 147,613 metric tonnes (MT) of solid waste is generated per day in the country. Part of the waste that is expunged on a daily basis from homes, is food and other kitchen waste, which are biodegradable or compostable. In rural areas, such waste is disposed of in landfills, such that they get decomposed to form compost that is used as manure for crops. But this is not feasible in large cities where empty land, as well as the time required for waste to get converted into compost, is in short supply. Composting is a proven method to reduce the volume of waste, to almost 15-20% of its original amount. Therefore, this work is focused on designing an electric composter that could decompose waste artificially, and is compact, efficient, odourless, and easy to operate. This product can thus manage biodegradable waste at the source of its generation, and effectively supplant the wastebasket in a kitchen by occupying no greater space than the latter. The yield of compost would also provide nutritive natural fertilizer to homes wherein kitchen gardens or terrace farms have been set up, as well as promote the creation of the same wherever space is available. In this paper, the important parameters involved in the design of composter, including geometry parameters and the ones of operational significance such as speed and number of blades of agitator and bin temperature, have been discussed thoroughly, along with providing an understanding of the processes and considerations necessitated.

Scale-up and flow behavior of cohesive granular material in a four-bladed mixer: effect of system and particle size

Flow of cohesive granular materials with different moisture contents was examined in a four-bladed mixer via the discrete element method (DEM). Firstly, the mixer diameter (D) was increased while keeping the particle diameter (d) constant. It was observed that when the mixer diameter to the particle diameter ratio (D/d) was larger than a certain critical size (D/d ≥ 75), granular flow behaviors and mixing kinetics followed simple scaling relations. For D/d ≥ 75, flow patterns and mixing kinetics were found to be independent of system size, and velocities of particles scaled linearly with the tip speed of the impeller blades and particle diffusivities scaled with the tip speed of the blades and mixer diameter. These results suggest that past a certain system size the flow and mixing of cohesive particles in large-scale units can be predicted from smaller systems. Secondly, system size was kept constant and particle diameter was changed and it was observed that by keeping the Bond number constant (by changing the level of cohesion) the flow behavior and mixing patterns did not change, showing that larger particles can be used to simulate flow of smaller cohesive particles in a bladed mixer by matching the Bond numbers.

Nomogram for single-pass automated microkeratome graft preparation for ultrathin Descemet stripping automated endothelial keratoplasty.

To create a nomogram including the translational speed of the microkeratome blade, microkeratome head size and precut tissue thickness to predict the postcut thickness for Descemet stripping automated endothelial keratoplasty to obtain the thinnest possible graft. This prospective study incorporated 48 grafts for DSAEK from March 2017 to June 2020. Corneal tissue for DSAEK was prepared by 3 experienced physicians using the Moria Evolution 3E (Moria Inc, Antony, France) microkeratome with 400, 450 and 500μm head sizes. Precut central corneal thickness was measured with a DGH 550 handheld pachymeter (Pachette 2), taking an average of 3 readings. The microkeratome head was selected according to precut tissue thickness. The selected microkeratome head size was 150μm less than the donor cornea thickness. Two translational speeds were used for the microkeratome cuts. One month after surgery, the central lenticular thickness was measured with a Visante® Optical Coherence Tomography caliper (Carl Zeiss Meditec Inc, Germany). A descriptive analysis was performed. Forty-eight donor grafts were prepared. Mean graft thickness was 97.58 ± 29.84μm (range 39-176μm). Of the 48 samples, central graft thickness was < 120µm (81.3%) in 39, < 100µm (58.3%) in 28 and < 80µm (37.5%) in 18 at 1-month follow-up. There were no statically significant differences between translational speeds. A nomogram with an automated microkeratome to obtain thin grafts for DSAEK provided good graft thickness results without donor waste.

Geometric and kinematic parameters of vibrating knife in the development of cutting machines

The process of cutting with a blade is largely applied in agricultural equipment and is used to process raw materials with different physical and mechanical properties. Nonetheless, the functional relation between the kinematic parameters of a vibroblade and the crucial power parameters of the vibration processing has not yet been studied in great depth so far. This type of studies is essential to create databases for further investigation and design of novel cutting machinery or technologies to ensure effective processing of vibrocutting. Our objective was to obtain the power characteristics of vibrocutting through laboratory experiments [using the example of vibrocutting of common reed (Phragmites australis)] and define the combination of factors (i.e., vibration amplitude, frequency and the blade feeding speed) at the minimum cutting force. The following relation of the blade feeding speed (V) and vibration speed of the toothed blade (Vt) has been established as optimal kinematic regime: K≅0.004. Tests have indicated that use of toothed blades for vibrocutting of the raw products of plant origin offers a greater advantage over the blades with flat edges. An optimal cutting regime, when energy expenses are at a minimum, was ensured with the following parameters of the vibroblade: vibration amplitude: 14 mm, frequency: 33.32 s–1, the blade feeding speed: 7.5×10–3 m.

DEM simulation of energy transitions in a hammer mill: Effect of impeller configurations, agitation speed, and fill level

In this study, a numerical approach is employed to investigate the flow and energy transitions characteristics of particles in a horizontal drum equipped with rotational flat blade. The results indicated that the dominant energy dissipation mechanisms were the internal friction between particles, the friction between particles and wall, and the damping loss of collision between particles. The mean tangential velocity and blade torque increased monotonously with the increase of fill level and blade speed. The dimensionless mean velocity in the tangential direction was dependent on the fill level and mill geometry instead of impeller agitation rate. In sequence, the characteristic parameters related to the geometric features and operational conditions were established to characterize the energy input in the agitator. The blade torque was characterized as a linear function of the characteristic parameter TS, which is determined by mill geometry and operational conditions.

Effect of contact temperature, normal load and dry sliding velocity on the coefficient of friction and wear behavior of nickel based super alloy

PurposeThe purpose of the present paper aims to, study the coefficient of friction and wear behavior of nickel based super alloys used in manufacturing of gas and steam turbine blades. In present paper, parametric study focuses on normal load, dry sliding velocity and contact temperature influence on coefficient of friction and wear of a nickel based super alloy material.Design/methodology/approachExperimental investigation is carried out to know the effect of varying load at constant sliding velocity and varying sliding velocity at constant load on coefficient of friction and wear behavior of nickel based super alloy material. The experiments are carried out on a nickel based super alloy material using pin on disk apparatus by load ranging from 30 N to 90 N and sliding velocity from 1.34 m/s to 2.67 m/s. The contact temperature between pin and disk is measured using K-type thermocouple for all test conditions to know effect of contact temperature on coefficient of friction and wear behavior of nickel based super alloy material. Analytical calculations are carried out to find wear rate and wear coefficient of the test specimen and are compared with experimental results for validation of experimental setup. Regression equations are generated from experimental results to estimate coefficient of friction and wear in the range of test conditions.FindingsFrom the experimental results, it is observed that by increasing the normal load or sliding velocity, the contact temperature between the pin and disk increases, the coefficient of friction decreases and wear increases. Analysis of variance (ANOVA) is used to study the influence of individual parameters like normal load, dry sliding speed and sliding distance on the coefficient of friction and wear of nickel based super alloy material.Originality/valueThis is the first time to study effect of contact temperature on the coefficient of friction and wear behavior of nickel-based super alloy used for gas and steam turbine blades. Separate regression equations have been developed to determine the coefficient of friction and wear for the entire range of speed of gas turbine blades made of nickel based super alloy. The regression equations are also validated against experimental results.

Investigation of the Solidity Ratio in a Horizontal Wind Turbine

A wind turbine-generator system; Parameters such as wind speed, turbine blade diameter, number of blades, turbine height, tip speed ratio and solidity ratio are affected. In this study, horizontal axis wind turbine with diameter of 130 cm and blade solidity ratio values of 7%, 8,6% and 9,8% were constructed and the tests were made according to different blade speed ratios. The required blades were obtained from PVC pipes of different diameters. The experimental study was actualized in Erciyes University Mechanical Engineering, Engines Laboratory. For each profile, blade rotational speeds and wind speeds at various distances have been studied. It has been determined that the wind speed is reduced by the distance difference and accordingly the number of blade speed is decreased visibly. In the wing profiles with different blade solidity ratios resulting from the work done, the wing structure with the solidity ratio of 8.6% gave the best performance. CL and CD coefficients of the profiled specimens were analyzed by FLUENTTM, a program of computational fluid dynamics. One of the factors that should be taken into consideration in the production of wind turbines is the blade solidity ratio.

Parametric study of flapwise and edgewise vibration of horizontal axis wind turbine blades

In this paper, flapwise and edgewise vibrations of a horizontal axis wind turbine (HAWT) blade are studied. Rayleigh-Ritz method is used in which; orthogonal mode functions of the Euler-Bernoulli beam having fixed-free boundary are introduced into the Lagrange function and then the dynamic equations are derived. Effect of gravity, pitch angle, centrifugal stiffening, and rotary inertia are considered. Nondimensional equations are obtained by defining nondimensional parameters like; natural frequency, blade rotation, slenderness ratio, and simple pendulum frequency. The stiffness term of the natural frequency has two speed dependent elements and it is shown that, for small pitch angles, flapwise natural frequencies of the blade are increased by the increasing blade speed while the edgewise natural frequencies of the blade are decreased with the increasing blade speed. Pitch angle values ranging from 0° to 15° has negligible effect on the nondimensional natural frequencies of the blade up to the nondimensional blade speed of 4. Since the natural frequencies are the function of the blade speed, rotor critical speeds should be calculated with Campbell diagrams. Vibrational response of the blade tip to the gravity is dominant and much greater than that of the wind speed in the edgewise and flapwise vibration.