The DESIGN OF A TRANSMISSION SYSTEM ON A BALL MILL MACHINE TO PROCESS HOMOGENIZATION OF BLACK POWDER USING AN AUTOMATIC SYSTEM

In the military world, battle technology has experienced very rapid development, both close-range combat and long-range combat. In long-distance combat the technology that is often used is rocket technology where this rocket technology can paralyze the enemy in large numbers. Black powder is a mixture of potassium nitrate (KNO3), carbon powder (C) and sulfur (S). (Evie Lestariana, LAPAN). The black powder itself functions as an igniter filling material for the propellant combustion process. This research is to design a tool to support the manufacture of black powder in the igniter filling to help the combustion of rockets, especially those owned by the Indonesian Army. This study uses an experimental method using empirical calculations to get a tool with the desired specifications. Before carrying out the calculations, the author collects research data to carry out calculations, the data collected are as follows: 1. Roller shaft rotation: 246 rpm, 2. Roller shaft torque: 4.0697 Nm, 3. Roller shaft diameter: 25 mm, 4. Pulley shaft diameter top: 100mm. The results obtained after carrying out the calculations are the diameter of the driving pulley 98 mm, the belt contact angle against the pulley 174.6º, and the length of the V-belt 453.14 mm, moment of inertia on the gearbox output shaft 1884,8 mm4.

Does Proximal Hip Geometry Affect Fracture Type in The Elderly Population?

Background The aim of this study was to determine the differences in proximal femoral geometric (PFG) parameters between patients with femoral neck fractures(FNFs) and patients with intertrochanteric fractures (ITFs). Methods We retrospectively evaluated 114 patients (33 FNFs, 81 ITFs.) who were hospitalized secondary to hip fractures. Patients were divided into two groups: patients with FNFs and patients with ITFs. The PFG parameters (the neck shaft angle, center-edge angle, femoral head diameter, femoral neck diameter, neck/head ratio, femoral neck axial length, femoral shaft diameter, hip axial length, and neck/hip length ratio) were measured on the hip joint radiographs. Results There were no statistically significant differences in age and gender between the FNF and ITF groups. In addition, there were no statistically significant differences in the PFG parameters between the FNF and ITF groups except in the neck/hip length ratio (NHLR) (0.86 ± 0.03 vs 0.84 ± 0.03, p = 0.05). When a 3-way multivariate analysis was performed according to gender, fracture type, and fracture site, the femoral head diameter, femoral neck diameter, femoral neck axial length, femoral shaft diameter, hip axial length, and NHLR were found to be greater in females than in males, and a statistically significant relationship was found between gender and these variables. Conclusion Only the NHLR was significantly higher in the ITF group, so this study revealed that a higher NHLR, which is the presence of a longer hip axis combined with a shorter neck axis, is a risk factor for ITF after a minor trauma.

Female Pattern Hair Loss in Female and Male: A Quantitative Trichoscopic Analysis in Chinese Han Patients

Objectives: To investigate the trichoscopic features of female pattern hair loss (FPHL) in Chinese Han patients and analyze the difference between male and female patients with FPHL.Materials and Methods: Trichoscopic images were taken in four different scalp areas, including right frontal hairline, vertex, right parietal and occipital areas. Hair density, hair shaft diameter, vellus hair ratio and single hair follicle unit ratio were counted manually and analyzed.Results: Seventy-three subjects were enrolled in this study, including 38 patients with FPHL (28 females and 10 males) and 35 normal controls without hair loss. The hair density and hair shaft diameter of FPHL patients reduced in the whole scalp. Vellus hair ratio and single hair follicle unit ratio were both increased in FPHL compared to normal controls. The vertex was the most affected area and the hair shaft diameter showed the most significant difference. Parietal and occipital area were also affected in FPHL. The reduction or increase was correlated with the severity of Ludwig staging. Very few gender differences were detected in male and female FPHL patients.Conclusion: FPHL patients showed decreased hair density and hair shaft diameter, accompanied by increased vellus hair ratio and single hair follicle unit ratio. Parietal and occipital area can be also affected in FPHL, though not as severe as in vertex area. FPHL in male basically has the same characteristic as those in female patients.Limitation: The main limitation of the study is the small sample size which only enrolled 10 male FPHL patients, in comparison to the female cases. The findings could not be representative of the normal population with the limited sample size.

Optimal weight design problem of spur gears

Gear is one of the most common and important components in machinery. Evaluation on durability of gears plays crucial role in the assessment of the whole system reliability and service life. For other parts like shafts, the gears also act as loads. Therefore, dimensions and weight of the gears should be reduced as much as possible, contributing the size and weight reduction of the whole systems, which is essential to be cost-effectiveness. The current research focuses on optimal weight design problem of spur gears, such that the weight is minimized under the constraints taken from working conditions. The weight is a function of six variables, i.e. face width, shaft diameter of pinion, shaft diameter of gear, number of teeth on pinion, module and hardness. Constraints are derived based on AGMA standard and engineering handbooks, including the bending strength, the surface fatigue strength, the interference condition, the condition for uniform load distribution, the torsional strength of shaft on pinion and gear, and the center distance. The set of optimum design variables is determined by the heuristic algorithm Grey Wolf Optimizer (GWO). The accuracy and efficiency of the GWO in the optimal weight design problem of spur gears are assessed based on comparison with other popular methods, such as Genetic Algorithm (GA), Particle Swarm Optimization (PSO) and Simulated Annealing (SA). It is noted that in previous works, some of the constraints are still violated. Therefore, a penalty term is taken into the objective function, such that any set of design variables that violates constraints will be considered as ``unfit'' by the algorithm. It is demonstrated that using the proposed approach by current work, the optimal weight and the corresponding set of design variable are very close to reference data. Yet the advantage of the proposed approach is exhibited in the fact that all of the constraints are satisfied.

A detailed study on design, fabrication, analysis, and testing of the anti-roll bar system for formula student cars

This study explains a coherent flow for designing, manufacturing, analyzing, and testing a tunable anti-roll bar system for a formula student racecar. The design process starts with the analytical calculation for roll stiffness using constraining parameters such as CG (Center of Gravity) height, total mass, and weight distribution in conjunction with suspension geometry. Then, the material selection for the design i.e. Aluminum 7075 T6 is made based on parameters such as density and modulus of rigidity. A MATLAB program is used to iterate deflection vs load for different stiffness and shaft diameter values. This is then checked with kinematic deflection values in Solidworks geometry. To validate with the material deflection, finite element analysis is performed on ANSYS workbench. Manufacturing accuracy for the job is checked using both static analysis in lab settings and using sensors on vehicles during on-track testing. The error percentage is found to be 4% between the target stiffness and the one obtained from static testing. Parameters such as moment arm length, shaft diameter and length, and deflection were determined and validated. This paper shows the importance of an anti-roll bar device to tune the roll stiffness of the car without interfering with the ride stiffness.

A Model of Diameter Measurement Based on the Machine Vision

If the shaft diameter can be measured in-situ during the finishing process, the closed-loop control of the shaft diameter processing process can be realized and the machining accuracy can be improved. Present work studies the measurement of shaft diameter with the structured light system composed of a laser linear light source and a camera. The shaft is a kind of part with rotationally symmetric structure. When the linear structured light irradiates the surface of the shaft, a light stripe will be formed, and the light stripe is a part of the ellipse. Therefore, the in-situ measurement of the shaft diameter can be realized by the light stripe and the rotational symmetry of the shaft. The measurement model of shaft diameter is established by the ellipse formed by the intersection of the light plane and the measured shaft surface. Firstly, in the camera coordinate system, normal vector of the light plane and the coordinates of the ellipse center are obtained by the calibration; then, the equation of oblique elliptic cone is established by taking the ellipse as the bottom and the optical center of the camera as the top. Next, the measurement model of shaft diameter is obtained by the established oblique elliptic cone equation and theoretical image plane equation. Finally, the accuracy of the measurement model of shaft diameter is tested by the checkerboard calibration plate and a lathe. The test results show that the measurement model of shaft diameter is correct, and when the shaft diameter is 36.162mm, the speed is 1250r/min, the maximum average measurement error is 0.019mm. The measurement accuracy meets the engineering requirement.

Hearing results after stapedotomy for otosclerosis: comparison of prosthesis variables

ObjectiveTo evaluate the influence of different piston variables on hearing following stapedotomy.MethodsData were analysed in groups according to: piston material (titanium vs fluoroplastic), shaft diameter (0.4 mm vs 0.5 mm) and crimping style (manual crimping vs self-crimping). Pre- and post-operative average air–bone gap, air–bone gap difference, success rate and operative time were evaluated.Results and conclusionFifty-one patients (58 ears) were included. A post-operative air–bone gap of 10 dB or lower was achieved in 44 cases, with a success rate of 75.9 per cent; 52 cases (89.7 per cent) had an air–bone gap of 20 dB or lower. The success rate was higher, but not significantly, in fluoroplastic than in titanium pistons (85 per cent vs 70 per cent). Pistons with shaft diameters of 0.5 mm and 0.4 mm had success rates of 79 per cent and 72 per cent, respectively. No significant differences were found for any audiometric parameters. There were no significant differences between manual crimping and self-crimping pistons in terms of audiometric results or success rate.