Shaft Size Research Articles

Aerodynamic Performance of a Hovering Cycloidal Rotor: A CFD Study with Experimental Validation

A three‐dimensional (3D) unsteady Reynolds averaged Navier‐Stokes (URANS) computational fluid dynamics (CFD) toolkit for cycloidal rotors was developed and used to perform a parametric study. It included blade aspect ratio, side disks, pitch mechanism, blade camber, and shaft size. The influence of the pitch rod length showed the importance of the lift distribution between the upstream and downstream parts of the rotor cylinder. The application of blade camber significantly affected thrust and power, while having a limited effect on efficiency. A similar effect was obtained by varying the pitch rod lengths. The presence of a central axis in the rotor had a negligible effect on efficiency. The most significant impact on efficiency came from the side disks, which behaved similarly to winglets on fixed‐wing aircraft. However, changing the aspect ratio of the blades showed a similar response to that of aircraft wings, but with a smaller effect, making it conceivable to fly a square-bladed cyclorotor without side disks. To verify the CFD model, a cycloidal rotor was also built using 3D printed parts and carbon fiber tubing. It was then operated on a test rig where thrust and power were measured for speeds ranging from 408 to 2528 RPM. On the test bench, the blades were pitched with a uniform asymmetric mechanism. The maximum nose‐up pitch angle in upstream of the rotor axis was 34.8°. Due to its rotation around the rotor and its pitching in the opposite direction, the maximum nose‐up pitch angle of the downstream blade was 38.6°. The obtained rotor thrust and power curves and the flow visualization around the rotor confirmed the validity of the CFD toolkit.

Finite element analysis part 1 of 2: Influence of short stem implant polyethylene configuration on glenohumeral joint biomechanics

AbstractPurposeStress shielding in short‐stem arthroplasty can cause critical metaphyseal bone loss. If the size and shape of the humeral shaft are important factors, it is unknown whether the shape of the polyethylene component in reverse shoulder arthroplasty (RSA) affects bone stress around or within the stem. We explored the impact of polyethylene shape on humeral and scapular stress distribution using a finite element model.MethodsWe developed a shoulder‐specific finite element model. A defined set of muscle forces was applied to simulate movements. An intact rotator cuff state and a superior deficient rotator cuff state were modelled. We used the FX V135 short stem in three conditions: total shoulder arthroplasty (TSA), and RSA with symmetrical and asymmetrical polyethylene (145°/135°). We measured biomechanical markers related to bone stress for different implant sizes. Joint kinematics and the mechanical behaviour of the implant were compared.ResultsRupture of the supraspinatus muscle produced a functionally limited shoulder. The placement of an anatomic TSA with an intact rotator cuff restored function similar to that of a healthy shoulder. RSA in the rotator cuff‐deficient shoulder restored function regardless of stem size and polyethylene shape. While stem size had an impact on the stress distribution in the bone and implant, it did not show significant potential for increasing or decreasing overall stress. For the same stem, stress distribution at the humerus is different between TSA and RSA. Polyethylene shape did not alter the transmission of stress to the bone in RSA. Asymmetric polyethylene produced a greater abduction range of motion.ConclusionsIn terms of bone stress distribution, smaller stems seemed more appropriate for TSA, while larger stems may be more appropriate for RSA. Polyethylene shape resulted in different ranges of motion but did not influence bone stress.Level of EvidenceDiagnostic Tests or Criteria; Level IV.

Constant static pressure strategy for residential kitchen exhaust system: Deducing control parameters from required exhaust rate and non-distributed data transmission

Roof fans have gradually replaced the non-powered hood as supplementary power to increase exhaust rate in high-rise residential kitchen shafts. However, an effective control strategy for roof fans is lacking. This paper studies the constant static pressure strategy and deduces its control parameters based on required exhaust rate and non-distributed data transmission. First, the static pressure set value (SV) is investigated under the worst exhaust condition, considering variations in shaft heights and measuring positions (MP). Then, an on/off mechanism is set up based on the measured static pressure and the fan frequency when the exhaust rate is adequate. Results show that under the recommended shaft sizes and design concurrent usage rates, the SVs for users' exhaust rate reaching 500 m³/h are −60, −60, and 0 Pa for 10/18/26-floor shafts when the MP is at a shaft's outlet, and roof fans are turned on when the static pressure reaches 100, 90, and 90 Pa and turned off when the fan frequency is below 32, 30, and 22 Hz. The MP at the shafts' outlet can keep the shaft at a slightly negative pressure. Control parameters for specific applications can be obtained through the proposed calculation process. An 18-floor shaft study found that the constant static pressure strategy can achieve 50 % energy savings compared to the constant frequency operation of the roof fan. These findings contribute to reliable control without users' distributed data transmission and to lower energy consumption of the residential kitchen exhaust system.

ON THE ISSUE OF COMPREHENSIVE ASSESSMENT OF THE IMPACT OF THERMAL RADIATION AT WORKPLACES, TAKING INTO ACCOUNT AIR POLLUTION

Problem statement. The research demonstrates that existing methods for determining the distribution of thermal radiation intensity using nomograms and formulas contain significant errors. This is due to the adoption of a number of simplifications regarding numerous interdependent parameters, including the temperature inside furnaces, the size of openings and shafts, etc. As a result, there is a need for measurements of thermal radiation intensity at distances of 5−10 meters and beyond. The purpose of the article. The objective of the article is to propose a concept for a new experimental methodology to investigate the intensity of radiation exposure to workers at their workplaces. Simultaneously, in order to address the issues of thermal protection for workers, actual measurement data of thermal radiation levels are necessary for each workstation under real working conditions within the workspace. Conclusion. It is important to characterize the composition of the gas environment, as its impurities can distort the distribution of radiant energy through interference and diffraction effects, which need to be considered for microclimate optimization. The presence of dust particles complicates the straight-line heat transfer through scattering and scintillation of rays, requiring further improvement of models. Turbulence, impurities, and atmospheric heterogeneity are important factors that need to be further investigated and taken into account in heat transfer process modeling. Scintillation affects the quality of radiation transmission, necessitating further study of this phenomenon. Local atmospheric composition peculiarities require the development of models that consider these variations. The obtained experimental data will contribute to improving the accuracy of modeling and enhancing working conditions. Further refinement of measurement techniques is necessary for obtaining reliable information.

Single-use flexible ureteroscopes: practice patterns, attitudes, and preferences for next-generation concepts.

Single use flexible ureteroscopes (su-fURS) have emerged as an alternative to reusable flexible ureteroscopes (r-fURS) for the management of upper urinary tract calculi. However, little is known about urologist usage and attitudes about this technology. Through a worldwide survey of endourologists, we assessed practice patterns and preferences for su-fURS. An online questionnaire was sent to Endourology Society members in January 2021. The survey explored current su-fURS practice patterns, reasons for/against adoption, and preferences for next generation models including developments in imaging, intra-renal pressure, heat generation, and suction. Responses were collected through QualtricsXM over a 1-month period from surgeons in North America, Latin America, Europe, Asia, Africa, and Oceania. The study was conducted according to the Checklist for Reporting Results of Internet E-Surveys (CHERRIES). 208 (13.9%) members responded to the survey. Most respondents (53.8%) performed >100 ureteroscopies per year. 77.9% of all respondents used su-fURS for less than half of all procedures while only 2.4% used su-fURS for every procedure. 26.0% had never used a su-fURS. Overall, usage was not influenced by a surgeon's geographic region, practice environment, or years of experience. Top reasons for not adopting su-fURS were cost (59.1%) and environmental impact (12.5%). The most desired improvements in design were smaller outer shaft size (19.4%), improved optics and vision (15.9%), and wireless connectivity (13.6%). For next generation concepts, the functions most commonly described as essential or important by respondents was the ability to suction fragments (94.3%) while the function most commonly noted as not important or unnecessary was incorporation of a temperature sensor (40.4%). su-fURS are not commonly used, even among urologists who perform a high number of fURS. The primary concern for adoption is cost and environmental impact. Suction capability was considered the most important future development.

Study on flow characteristics of exhaust shaft with parallel fans in high-rise residential buildings

The exhaust shaft is often used to centrally extract cooking fumes captured by parallel fans on each floor of high-rise buildings. Inadequate airflow rate and excessive pressure in the exhaust shaft lead to poor ventilation and unsatisfactory air quality in kitchens. This issue is made worse by mixed installations of exhaust fans with different dynamic performances. In this study, the flow characteristics in the exhaust shaft with parallel fans are investigated by full-scale experiments and computational fluid dynamics (CFD). Based on the orthogonal experimental design, the cross-sectional area, concurrent operating rate, operating position distribution, and P-Q curves are key factors affecting the flow rate distribution significantly. Mixed installation of fans deteriorates the uniformity of the flow distribution along the shaft by even 62.6%. The competition for flow rate between different types of fans is obeying the Matthew effect. Concentration at the bottom and more simultaneous operations exacerbate this problem. An 28% enlargement in the shaft size increases the flow rate by 28.9% and improves the uniformity of the flow distribution by 50%. The stack effect is positive and unstable, with up to a 6.49% increase in system flow rate as a function of the cooking heat intensity. This work can provide guidance for the design of centralized exhaust systems in high-rise residential buildings.

Subtunical Reduction Clitoroplasty of a 22 years old Female for Clitoromegaly with Congenital Adrenal Hyperplasia-Case Report

Clitoromegaly is an abnormal condition commonly related to congenital adrenal hyperplasia. We presented a 22 years old adult female patient with chief complaint of enlarged clitoris since birth, other female secondary sexual characteristics were normal. The karyotype test result was 46 XX. Subtunical resection of erectile cavernous tissue of the enlarged clitoris with preservation of intact blood supply to the glans is a safe method of diminishing shaft and glans size and allow the patient to do sexual activity after marriage during a two-years follow up. Bangabandhu Sheikh Mujib Med. Coll. J. 2023;2(2):127-130.

A Study on the Behavior Characteristics of Air Supply during Tunnel Fires under Natural Ventilation with Multiple Vertical Shafts

This study investigates the behavior of air supply in tunnels with multiple vertical shafts during fire incidents, focusing on natural ventilation dynamics. Numerical simulation is utilized to analyze the effect of different variables on air supply within vertical shafts. The findings reveal that the position of the smoke front significantly influences the direction and flow rate of gases during fire development. The mass flow rate of air supply during the stable fire development stage is influenced by the geometric size and positioning of vertical shafts, with shafts closer to the fire source exhibiting higher air flow rates. To address this issue, this study introduces a predictive model for estimating air flow rates in vertical shafts. This model exhibits a high level of accuracy when compared to simulations, offering a reliable method for predicting air flow rates based on the geometric characteristics of vertical shafts. Overall, this research contributes to understanding the complexities of air supply in tunnels with multiple vertical shafts, aiding in the improvement of natural ventilation strategies during fire incidents.

Effect of Thermal Response and Vibration on the Multicracked Rotor Immersed in a Fluid Medium Using Finite Element Method

A rotor shaft under high rotating speeds and heavy loading may establish fatigue damage in terms of cracks due to the long duration of the operation. Analysis of the size and location of the crack in the rotor shaft becomes very difficult, especially while the rotor shaft revolves in a viscous fluid medium. This research is an attempt to measure the vibration signature of a multicracked cantilever rotor shaft with additional mass at the free end in a different fluid medium at a finite region. The dynamic response of a cracked cantilever rotor shaft, with additional mass at the free end, partly immersed in air and diverse viscous mediums are measured experimentally. The existence of open cracks in the rotor shaft in both transverse directions, along the crack and perpendicular to the crack, was considered. The experimental analysis is performed to examine the variation in vibration response with varying the size of the rotor shaft, crack depth, and fluid properties. The finite element analysis technique is employed by using ANSYS to authenticate the vibration response of the same multicracked cantilever rotor shaft in air and different viscous mediums.

Perancangan Mesin Penyangrai Kopi Tipe Rotari Berbasis Mikrokontroler Arduino

Coffee is one of Indonesia's leading export commodities in the agricultural sector. Good coffee quality makes Indonesia one of the largest coffee exporting countries in the world. The process of making coffee involves many stages or processes, from harvesting to producing coffee grounds. One of the important stages in coffee production is the process of roasting the coffee beans. This study aims to design a rotary type coffee roaster based on Arduino Microcontroller. The working principle of this machine is to control the temperature and rotation of the roasting cylinder using the Arduino Uno as the controller for the temperature sensor and motor. The method used in this study is the design method, namely the design calculations are carried out on the supporting elements of the coffee roaster machine. From the design, the engine specifications are obtained with a cylinder size of 500 mm long, 130 mm radius, maximum rotation of 80 Rpm, 1HP electric motor and 28 mm shaft size.

Quenching with Aqueous Polymer Solutions

Abstract Quenching with aqueous polymer solutions has some distinct advantages over classical oil quenching. Among these are the good environmental properties and the possibility to adjust the quenching performance between oil and water quenching. Nevertheless, critical aspects must also be taken into account. When quenching steel parts with polymer solutions, “explosion-like” phenomena can occur, often accompanied by large cooling rate changes. These “explosions” can lead to pressure waves and vibrations in the quenching tank, which in the long run can even destroy weld seams of the quenching tank. In the framework of a research project, experimental investigations were carried out in a laboratory quenching bath and in an industrial quenching tank. The polymer type, the type of incident flow, the flow velocity, the bath temperature and the size of the test shafts were varied. Near-surface temperature measurements inside the shafts were performed to characterize the resulting quenching processes. Simultaneously, electrical conductivity measurements and audio and video recordings were made to localize insulating films on the surface and their collapse. To systematize and characterize the large number of measurement results, characteristic types of cooling processes and characteristic numbers for their characterization were defined and will be presented in this paper.

PD45-12 COMPARISON OF INTRARENAL PRESSURE DURING RETROGRADE INTRARENAL SURGERY USING VARIOUS SINGLE-USE URETEROSCOPES: AN IN-VITRO STUDY

You have accessJournal of UrologyCME1 Apr 2023PD45-12 COMPARISON OF INTRARENAL PRESSURE DURING RETROGRADE INTRARENAL SURGERY USING VARIOUS SINGLE-USE URETEROSCOPES: AN IN-VITRO STUDY Shimpei Yamashita, Ryusuke Deguchi, Yuya Iwahashi, Masatoshi Higuchi, Takaaki Inoue, Yasuo Kohjimoto, and Isao Hara Shimpei YamashitaShimpei Yamashita More articles by this author , Ryusuke DeguchiRyusuke Deguchi More articles by this author , Yuya IwahashiYuya Iwahashi More articles by this author , Masatoshi HiguchiMasatoshi Higuchi More articles by this author , Takaaki InoueTakaaki Inoue More articles by this author , Yasuo KohjimotoYasuo Kohjimoto More articles by this author , and Isao HaraIsao Hara More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003358.12AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Various single-use ureteroscopes (su-URS) have been developed and become commercially available. The difference of scope size could lead to the difference of intrarenal pressure (IRP) during retrograde intrarenal surgery (RIRS). However, no previous study has directly compared IRP among different su-URS. The aim of this in-vitro study was to evaluate IRP during RIRS and compare those among various su-URS. METHODS: We created an artificial kidney model with a pressure sensor by using bladder evacuation device. The model was completely closed and the only back flow was on the side of the ureteroscope inside the ureteral access sheath (UAS) (Figure 1). We tested five su-URS (LithoVue, Wiscope, PU3022A, PU3033A and AXIS) with six different UAS (9.5/11.5Fr-14/16Fr). Using the automatic irrigation system, 30 seconds of irrigation was performed at various pressure (40-180mmHg) and steady state IRP was recorded. Six runs were tested per setting. We compared IRP among five su-URS. The diameter of endoscope tip and shaft were also measured and recorded. RESULTS: The diameter of endoscope tip was smallest in PU3033A, while the diameter of other endoscopes was almost similar. The diameter of endoscope shaft was largest in LithoVue, followed by PU3022A, AXIS, Wiscope and PU3033A. Measured IRP was different among su-URS, and endoscopes with larger shaft diameter tended to have higher IRP (Figure 2). Assuming that the cutoff value of IRP for the risk of postoperative sepsis was 30mmHg, the suitable size of UAS was considered to be 12/14Fr or more for LithoVue and PU3022A, 11/13Fr or more for AXIS and Wiscope and 10/12 Fr or more for PU3033A. CONCLUSIONS: Our results suggested that the size of endoscope shaft might affect IRP during RIRS, and IRP and suitable size of UAS could be different among various su-URS. Source of Funding: None. © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e1167 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Shimpei Yamashita More articles by this author Ryusuke Deguchi More articles by this author Yuya Iwahashi More articles by this author Masatoshi Higuchi More articles by this author Takaaki Inoue More articles by this author Yasuo Kohjimoto More articles by this author Isao Hara More articles by this author Expand All Advertisement PDF downloadLoading ...

New sauropod remains from the Middle Jurassic Dongdaqiao Formation of Qamdo, eastern Tibet

We report isolated postcranial materials newly excavated from the Middle Jurassic Dongdaqiao Formation in Chaya County, Qamdo City, eastern Tibet. The specimens are assignable to Eusauropoda based on the following combination of characters: huge size of caudal vertebrae and humeral shaft, weakly developed amphicoelous caudal centrum, femoral distal ends with two condyles and a shallow intercondylar groove, and rod-like transverse process of the anterior caudal vertebra with its base not extending to the neural arch. Due to the fragmentary nature of the specimens, we refrain from assigning them to lower taxonomic levels or new species of sauropod until more complete materials are excavated from Qamdo. Nevertheless, the new materials from Qamdo demonstrate that some gigantic sauropods migrated to eastern Tibet during the Middle Jurassic and were more widely distributed than previously known.

Engineered Nanovesicles from Fibroblasts Modulate Dermal Papillae Cells In Vitro and Promote Human Hair Follicle Growth Ex Vivo.

Alopecia is a common medical condition affecting both sexes. Dermal papilla (DP) cells are the primary source of hair regeneration in alopecia patients. Therapeutic applications of extracellular vesicles (EVs) are restricted by low yields, high costs, and their time-consuming collection process. Thus, engineered nanovesicles (eNVs) have emerged as suitable therapeutic biomaterials in translational medicine. We isolated eNVs by the serial extrusion of fibroblasts (FBs) using polycarbonate membrane filters and serial and ultracentrifugation. We studied the internalization, proliferation, and migration of human DP cells in the presence and absence of FB-eNVs. The therapeutic potential of FB-eNVs was studied on ex vivo organ cultures of human hair follicles (HFs) from three human participants. FB-eNVs (2.5, 5, 7.5, and 10 µg/mL) significantly enhanced DP cell proliferation, with the maximum effect observed at 7.5 µg/mL. FB-eNVs (5 and 10 µg/mL) significantly enhanced the migration of DP cells at 36 h. Western blotting results suggested that FB-eNVs contain vascular endothelial growth factor (VEGF)-a. FB-eNV treatment increased the levels of PCNA, pAKT, pERK, and VEGF-receptor-2 (VEGFR2) in DP cells. Moreover, FB-eNVs increased the human HF shaft size in a short duration ex vivo. Altogether, FB-eNVs are promising therapeutic candidates for alopecia.

A unified constitutive relationship with the internal state variables of grain evolution behavior and the application in numerical simulation of cross wedge rolling

Controlling the grain size is an essential issue in the metal plastic working processes. Based on the consensus view that grain boundaries are impassable borders for dislocations and that the number of dislocations within a grain affects the stress builds up among the adjacent grains, altering grain size has a great influence on the post-forming mechanical properties of the deformed workpieces. In the present research, the deformation behaviors of 20CrMoH, a typical hardenability steel, are investigated and the microstructure evolution of grain growth experiencing heat load and grain refinement under deformation load is also uncovered. According to the experimental stress-strain curves and grain size variation data, a set of internal variable constitutive equations are established, in which the material constants are calibrated by a genetic optimization algorithm. Comparing the predicted curves with the experimental values, it can be concluded that the constitutive equations can accurately reproduce the thermal deformation behaviors and grain size variation of the steel. The correlation coefficient of the calculated and experimental values is 0.9861, and the average relative error approximates 4%. The unified constitutive equations are compiled into a commercial finite element software with the help of user-defined subroutine interfaces. The simulation results demonstrate that the maximum accuracy error of a hollow shaft size is about 10%, and the error in the average grain size is 12.1%. It is confirmed that the internal variable constitutive equations describing the evolution of grain size established in this paper are suitable for the numerical simulation of the bulk-forming process.

A new oval shaft, high performance, 2 pole line start synchronous reluctance machine for submersible pump applications

In this paper, a 2 pole, 4 kW, 6 inches diameter line start synchronous reluctance machine (LS-SynRM) as a submersible water pump motor is designed and optimized with a new oval shaft structure. The aim is to improve the machine performance by widening the flux path on the rotor via narrowing down the shaft on the q-axis. This way a wider d-axis flux path is obtained, and accordingly, the d-axis inductance, the saliency ratio Ld∕Lq, and the inductance difference Ld–Lq are increased. First, a set of structural analyses is carried out on a 7-flux barrier rotor in 3 stages: modal, harmonic, and static structural analyses. According to analysis results, the safe limit for the shaft size reduction is determined as 8 mm to avoid excessive deformations and undesired vibrations due to resonance. Later, the machine is optimized using Multi-Objective Differential Evolution (MODE) algorithm with a narrower shaft. The quality of the Pareto front solutions shows that the oval shaft machine is superior to the circular shaft machine in terms of efficiency, motor mass, and torque ripple. The maximum recorded efficiency improvement for the same size LS-SynRM is 4 points and the same size commercial induction machine is around 20 points.

703 Tracing the proliferative dynamics of dermal papilla (DP) progenitors during adult hair follicle (HF) regeneration

The dermal papilla (DP) instructs the cyclical regeneration of the adult hair follicle (HF). The HF grows in anagen, regresses in catagen and rests in telogen. The DP expands in cell number as the HF regenerates, which is critical for HF growth and regulating hair shaft size. Currently how the DP expands is not clear. As the DP is considered to be a quiescent population, the prevailing theory is that the DP expands from proliferative cells that reside outside the DP. We performed EdU pulse chase experiments to track when and where DP progenitors divide and contribute to the expanding DP.

Selection and calculation of 10 kinds of lime slurry box mixer

Through to the mixer of the selection of each component analysis and introduction, aiming at 10 in the desulfurization denitration common specifications of the limestone slurry tank, mixer technology selection on the optimization design, analyzes how to do in the desulfurization denitration limestone slurry tank mixer optimization selection, so as to achieve the optimal land use effect and the technological requirement. The operation performance of the mixer is directly related to the quality, energy consumption, and production cost of the product. The engineering and academic circles have attached great importance to the mixing, conducted a lot of research work, and achieved a lot of research results. But in fact, stirring process is often accompanied by reaction process, its complexity lies in its principle involves flow field, fluid mechanics, heat transfer, mass transfer, and chemical reaction and other processes. In addition to the complexity of the material flow in the mixing equipment, it is a very complex mixing state, mixing effect is difficult to quantify through the form and size of the mixer, so as to complete under a strict theoretical guidance. At present, the selection of mixer and the design of its internal components are largely dependent on experiment and practical engineering experience. The advantages and disadvantages of product design can make the benefit of mixing equipment is very different, so on the basis of clear limestone slurry material properties, for each element of mixing equipment, such as the shape of the impeller, impeller diameter, layout layer number, speed, mixing shaft size, baffle size, and number of one optimization. By making full use of the comparative analysis of existing achievements, the design and selection of 10 common specifications and models of limestone grout box are optimized, so that the design theory of mechanical mixer is more perfect, and it can also meet the requirements of practitioners in the daily desulfurization and denitration industry on the selection of limestone grout box mixer.

Mixing simulation of cohesive particles in a soil mixer

Soil particle mixing is an important research hotspot in the emerging field of waste soil resources. In this study, the discrete element method (DEM) is used to characterize the mixing of cohesive particles in a soil mixer. To verify the mixing effect of this mixer on cohesive materials, the forces between the particles are simulated using a cohesive contact model. The effects of filling level, rotating shaft speed and size, particle cohesion and size on particle dynamics and mixing performance within the mixer are investigated. The mixing process of the particles is analyzed to quantify the mixing performance by using the coordination number (CN), average velocity, contact force network and mixing index. To assess the degree of mixing using the Lacey mixing index, a grid system is used to divide the mixing area so that the mixing index can be calculated. The results show that this mixer is suitable for mixing cohesive particles and that a lower filling level leads to better mixing efficiency. In addition, the mixing efficiency is significantly improved as the speed and size of the rotating shaft in the mixer increased.

NUMERICAL ANALYSIS OF THE VARIOUS SIZES OF SPIKE AND SHAFTS USED ON MAIZE SHELLING MACHINE IN NIGERIA USING FINITE ELEMENT METHOD

Selection of the optimum diameter of Spikes and Shafts used on Maize sheller in Nigeria is a major problem for the local fabricators due to which they either over size those components leading to high cost of the shellers or under size them leading to failure of the shellers during operation. To determine the optimum size of the spikes and shaft to be used on Maize sheller, Finite Element Analysis (FEA) were carried out using SolidWorks Premium 2019, to determine the maximum Vonmises Stress, deflection and minimum factor of Safety of those components using the most common size of spikes and shafts used in developing Maize shellers in Bauchi State Nigeria and to recommend the most suitable sizes to be used. From the Simulation of the various sizes of the spikes, it was found that the best size of ribars to be used as the spikes for maize Shellers is either 12 or 14 mm. 12 mm will be subjected to maximum Vonmises stress of 103.092 Mpa at a factor of safety of 2.716 while 14 mm will be subjected to a Maximum stress of 76.57 Mpa at a factor of Safety of 3.66. The most suitable Size for the Shelling shaft was determined to be 20 mm which will be subjected to a maximum Vonmises Stress of 73.32 Mpa at a factor of Safety of 4.8 with a maximum deflection of 0.09 mm.