A Practical Numerical Approach to Characterizing Non-Linear Shrinkage and Optimizing Dimensional Deviation of Injection-Molded Small Module Plastic Gears

This paper was aimed at finding out the solution to the problem of insufficient dimensional accuracy caused by non-linear shrinkage deformation during injection molding of small module plastic gears. A practical numerical approach was proposed to characterize the non-linear shrinkage and optimize the dimensional deviation of the small module plastic gears. Specifically, Moldflow analysis was applied to visually simulate the shrinkage process of small module plastic gears during injection molding. A 3D shrinkage gear model was obtained and exported to compare with the designed gear model. After analyzing the non-linear shrinkage characteristics, the dimensional deviation of the addendum circle diameter and root circle diameter was investigated by orthogonal experiments. In the end, a high-speed cooling concept for the mold plate and the gear cavity was proposed to optimize the dimensional deviation. It was confirmed that the cooling rate is the most influential factor on the non-linear shrinkage of the injection-molded small module plastic gears. The dimensional deviation of the addendum circle diameter and the root circle diameter can be reduced by 22.79% and 22.99% with the proposed high-speed cooling concept, respectively.

Noor's Curve, a New Geometric Form of Agnesi Witch, a Construction Method is Produced

In this paper, a new form of 2D-plane curves is produced and graphically studied. The name of my daughter "Noor" has been given to this curve; therefore, Noor term describes this curve whenever it is used in this paper. This curve is a form of these opened curves as it extends in the infinity along both sides from the origin point. The curve is designed by a circle/ ellipse which are drawing curvatures that tangent at the origin point, where its circumference is passed through the (0,2a). By sharing two vertical lined points of both the circle diameter and the major axis of the ellipse, the parametric equation is derived. In this paper, a set of various cases of Noor curve are graphically studied by two curvature cases; a circle and an ellipse, and all figures and obtained rigour measurements are checked by AutoCAD program. With its simple, symmetric form, the future predictions are tuned for the Noor's curve to be usefully engaged in important practical applications.

Study on a Chiral Structure with Tunable Poisson’s Ratio

A chiral structure with a negative Poisson’s ratio containing a hollow circle with varying diameters was designed, and the finite element method was used to investigate the variation in the Poisson’s ratio when the hollow circle diameter was varied (d = 0, 1, 2, 3, and 4 mm). The simulation results showed that the Poisson’s ratio was sensitive to the hollow circle diameter, and the minimum Poisson’s ratio was −0.43. Three specimens with different hollow circle diameters (d′ = 0, 1, and 3 mm) were 3D-printed from thermoplastic polyurethane, and the Poisson’s ratio and equivalent elastic modulus were measured. In the elastic range, the Poisson’s ratio increased and the equivalent elastic modulus decreased as the hollow circle diameter increased. The simulation and experimental results showed good agreement. The proposed structure is expected to be applicable to protective sports gear owing to its high energy absorption and the fact that its properties can be modified as required by adjusting the geometric parameters of the unit cell.

Sensitivity of Rodel Roundabout Delay Estimates to Input Parameters

Modern roundabouts are developed to increase the traffic capacity and decrease the traffic delay. They are popular around the world and are becoming common in Canada and the United States. A great design of a roundabout is to achieve the minimum delay. According to the research papers regarding the delay at roundabouts, it is expected the vehicle delay, the stop ratio at various traffic volumes, and the level of saturation of roundabouts are smaller than the amount of similar parameters on un-signalized intersections. The purpose of this thesis is clarification and measurement of the geometric parameters through the RODEL software to depict their influence on the sensitivity of roundabout delay. This study has been done through creation and analysis of numerous tables and graphs for various traffic volumes and peak periods. Furthermore, the required accuracy of each parameter in estimating delay of a planned roundabout is determined. The outcome of this analysis indicates the effects of the geometric parameters on the roundabout delay. While the Half Width, Entry Width, and Flare Length have the greatest influence on the delay, the Entry Radius, Entry Angle (PHI), and Inscribed Circle Diameter have the least influence.

Sensitivity of Rodel Roundabout Delay Estimates to Input Parameters

Modern roundabouts are developed to increase the traffic capacity and decrease the traffic delay. They are popular around the world and are becoming common in Canada and the United States. A great design of a roundabout is to achieve the minimum delay. According to the research papers regarding the delay at roundabouts, it is expected the vehicle delay, the stop ratio at various traffic volumes, and the level of saturation of roundabouts are smaller than the amount of similar parameters on un-signalized intersections. The purpose of this thesis is clarification and measurement of the geometric parameters through the RODEL software to depict their influence on the sensitivity of roundabout delay. This study has been done through creation and analysis of numerous tables and graphs for various traffic volumes and peak periods. Furthermore, the required accuracy of each parameter in estimating delay of a planned roundabout is determined. The outcome of this analysis indicates the effects of the geometric parameters on the roundabout delay. While the Half Width, Entry Width, and Flare Length have the greatest influence on the delay, the Entry Radius, Entry Angle (PHI), and Inscribed Circle Diameter have the least influence.

Object surface reconstruction from flow tracers

A method to identify the surface of solid models immersed in fluid flows is devised that examines the spatial distribution of flow tracers. The fluid–solid interface is associated with the distance from the center of a circle to the centroid of the tracers ensemble captured within it. The theoretical foundation of the method is presented for 2D planar interfaces in the limit of a continuous tracer distribution. The discrete regime is analyzed, yielding the uncertainty of this estimator. Also the errors resulting from curved interfaces are discussed. The method's working principle is illustrated using synthetic data of a 2D cambered airfoil, showing that one of the limitations is the treatment of an object thinner than the search circle diameter. The method is readily adapted to 3D and applied to the 3D PTV data of the flow around a juncture. The surface is reconstructed within the expected uncertainty, and specific limitations, such as the smoothing of sharp edges is observed. Graphic abstract

PENGGUNAAN RANGKAIAN BOOSTER CONVERTER DAN IC-TP4056 UNTUK LAMPU JALAN MURAH

PJU (Public Street Lighting), is regulated in the regulation of the Minister of Transportation of the Republic of Indonesia Number 27 of 2018, concerning street lighting. In line with the statement of the village minister, development of underdeveloped areas and transmigration (Mendes PDTT), eko putro Sandjojo, said that village funds could be used to make street lamps for villages that do not have street lights. The area of the northern ring road, sub-district of datuk bandar timur in the direction of the port of Teluk Nibung, part of the road has no street lighting at night, plus the road conditions are still classified as red soil. Based on the results of field observations, the team researched making cheap street lamps, by utilizing the basic work system of the joule tief circuit, where the input is 7.4 VDC (in 3.7VDC arranged in series-parallel) with a lamp load of 12 watts multiplied by 4 lamps, with a total load. 48 watts, get the frequency measurement results of 12.30 Khz and Iout 0.14A, and Vpk-pk 82 V. Charging input is 7.4VDC, the current 19800mAh in the battery is divided by the maximum current of the solar module 1 watt, which is 160mA, so the charging time the battery is in the range of 2.1 hours. For the design of the lampposts that were made, using a paralon pipe with a length of 5m, with a circle diameter of 9cm, and a second pole connecting 1.5 m long with a circle diameter of 5cm. Keywords: Cheap street lights; joule tief series; 1 watt solar panel Abstrak : PJU (Penerangan Jalan Umum), diatur dalam peraturan mentri perhubungan republik indonesia nomor 27 tahun 2018, tentang alat penerangan jalan. Sejalan dengan pernyataan mentri desa, pembangunan daerah tertinggal dan transmigrasi (Mendes PDTT) eko putro Sandjojo, mengatakan bahwa dana desa bisa digunakan untuk membuat lampu jalan bagi desa yang tidak memiliki lampu jalan. Wilayah jalan lingkar utara, kecamatan datuk bandar timur searah menuju pelabuhan teluk nibung, sebahagian dari jalan tersebut tidak memiliki penerangan jalan dimalam hari, ditambah dengan kondisi jalan yang masih tergolong tanah merah. Berdasarkan hasil pengamatan dilapangan maka tim meneliti membuat lampu jalan murah, dengan memanfaatkan dasar sistem kerja rangkaian joule tief, dimana untuk input 7,4 VDC (in 3,7VDC disusun seri-paralel) dengan beban lampu 12 watt dikalikan 4 lampu, dengan total beban 48 watt, mendapati hasil pengukuran frequensi 12,30 Khz dan Iout 0,14A, dan Vpk-pk 82 V. Pengisian input 7,4VDC didapati, arus 19800mAh pada baterai dibagi dengan arus maksimum modul surya 1 watt, yaitu 160mA, sehingga lama pengisian baterai berada pada rentang waktu 2,1 jam. Untuk rancangan tiang lampu yang dibuat, menggunakan pipa paralon dengan panjang 5m, dengan diameter lingkaran 9cm, dan penyambung tiang kedua sepanjang 1,5 m dengan diameter lingkaran 5cm. Kata Kunci : Lampu jalan murah; rangkaian joule tief; panel surya 1 watt

Experimental study on the reduction effect of pit texture on disassembly damage for interference fit

After remanufacturing disassembly, several kinds of friction damages can be found on the mating surface of interference fit. These damages should be repaired and the cost is closely related to the severity of damages. Inspired by the excellent performance of surface texture in wear reduction, 5 shapes of pit array textures are added to the specimens’ surface to study their reduction effect of disassembly damage for interference fit. The results of disassembly experiments show that the order of influence of texture parameters on disassembly damage is as follows: equivalent circle diameter of single texture，texture shape and texture surface density. The influence of equivalent circle diameter of single texture and texture shape are obviously more significant than that of texture surface density. The circular texture with a surface density of 30% and a diameter of 100μm shows an excellent disassembly damage reduction effect. The load-carrying capacity of interference fit with the excellent texture is confirmed by load-carrying capacity experiments. The results show that the load-carrying capacity of the excellent texture surface is increased about 40% compared with that of without texture.

Study on the morphology of Mature ovarian follicles using Image Processing Toolbox

Objective: This study aims to investigate the morphological characteristics of mature follicles with clinical value. Study Design:a retrospective studyMethods: The five morphological indexes of follicles in 72 natural ovulation cycles were measured. The shoot time of follicle photos was the day before ovulation. Measurement software was the MATLAB Image Processing Toolbox. Results: The measured average area, perimeter, equivalent circle diameter and roundness were 301.29 ± 8.52 mm2, 62.23 ± 6.82 mm, 20.21 ± 3.08 mm and 0.89 ± 0.05, respectively; and the maximal diameter was 23.12 ± 3.06 mm. Conclusion: Image Processing Toolbox is a simple and convenient measurement software. The standardization of the reference indexes of follicular morphology has an important clinical application value in reproductive medicine.Research Highlights and Graphical Abstract: In the present study, the morphological characteristics of these folliclesinclude the area, perimeter, maximal diameter, equivalent circle diameter and roundness were preliminarily studied using the related measurement software.