Pengaruh Geometri Gerigi dan Kecepatan Putar Terhadap Kinerja Mesin Parut Sagu Tipe Silinder

Sago rasping machine or sago rasper is the most commonly used in sago processing both for small and large scale. It function is to reduce the size or to disintegrate sago pith into smaller particle. By doing so, the starch contained in the pith can be separated in the subsequent process. The amount of starch resulted depend on the size of rasped pith. The smaller the pith is rasped the higher the starch can be extracted. The purpose of this research was to test the effect of teeth geometrical shape and cylinder rotation speed on performance of sago rasping machine. There are four type of teeth geometrical shape namely cylinder, pyramid, screw, and cube and three levels of cylinder rotation speed they are 1500 rpm, 2000 rpm and 2500 rpm were tested. Results showed that the rasping capacity was affected significantly by the two single factors as well as its interaction of teeth geometrical shape and cylinder rotation speed. Similarly, starch yield and starch losses in waste were significantly affected by teeth geometrical shape. Meanwhile, starch yield and starch losses in waste were not affected significantly by cylinder rotation speed and the interaction of the two factors. The best performance was resulted at the treatment of teeth geometrical shape of screw with the speed of cylinder rotation 2500 rpm. The performances at the treatment were: (a) rasping capacity was 918 kg/h, (b) starch yield was 48%, (wb), (c) starch loss in waste was15.1%.Keywords: cylinder type, rasping performance, sago rasping machine, teeth geometry

Numerical Thermal Analysis of a Hot Non-circular Rotating Cylinder in the Presence of a Magnetic Field

In the present paper for the first time, a Lattice Boltzmann Simulation is performed to analyze the simultaneous effects of a hot rotating elliptic cylinder and the magnetic field on the mixed convection flow in a square enclosure. Complicated flow patterns and isotherms plots are found and analyzed in the concentric annulus between the internal elliptic cylinder and the outer square enclosure. Results indicate that increasing the Reynolds number, instantaneous averaged Nusselt number of the enclosure and its oscillation amplitude increase, while decrease with increasing the Hartmann number especially at its lower values. Furthermore, response surface method is adopted to find the optimal location of the elliptic cylinder. Response surface optimization results reveal that the average Nusselt number shows a decreasing-increasing trend with increasing both non-dimensional parameters of cylinder center (Xc,Yc) Finally, the optimal location of the elliptic cylinder for the maximum heat transfer rate is obtained as Xc=0.65 and Yc=0.35. Moreover, a comparative study is performed to evaluate the heat transfer effects of the elliptical cylinder rotation as compared to circular cylinder. It was found that the elliptical cylinder rotation has a significant effect on the heat transfer enhancement, especially at high values of Re and Ha. As an example, the heat transfer rate for the elliptical cylinder at Re=200 is increased by 13 % and 34% as compared to the circular cylinder at Ha=50 and 100, respectively.

Numerical simulations of the polydisperse droplet size distribution of disperse blends in complex flow

The blend morphology model developed by Wong et al. (Rheologica Acta, 2019), based on Peters et al. (J Rheol 45(3):659–689, 2001), is used to investigate the development of the polydispersity of the disperse polymer blend morphology in complex flow. First, the model is extended with additional morphological states. The extended model is tested for simple shear flow, where it is found that the droplet size distribution does not simply scale with the shear rate, because this scaling does not hold for coalescing droplets. Subsequently, the model is applied to Poiseuille flow, showing formation of distinct layers, which occurs in realistic pressure-driven flows. Finally, the model is applied on an eccentric cylinder flow, where histograms are made of the average droplet size throughout the domain. It is observed that outer cylinder rotation results in narrow distributions where the small droplets are relatively large, whereas inner cylinder rotation results in broad distributions where the small droplets are significantly smaller than in the case of outer cylinder rotation. Eccentricity seems to only have a minor effect if the maximum shear rate is held constant. The flow profile and history in combination with the maximum shear rate strongly determine how the polydisperse droplet size distribution develops.

Performance Test of Various Teeth Diameter of Cylinder Type Sago Rasping Machine

Traditional method of sago starch extraction was a time and labor intensive process. The most laborious stage is pith disintegration which is done by using hammer-like tools called pounder. However, the use of rasping machine to disintegrate the pith is saving time and energy significantly. The objective of this study was to investigate the effect of teeth diameter and cylinder rotation speed on performance of cylinder type sago rasping machine. In the experiment, four variations of teeth diameter i.e. 3mm, 4 mm, 5 mm and 6 mm, and three levels of cylinder rotation speed i.e. 1500 rpm, 2000 rpm and 2500 rpm were examined. Results showed that both teeth diameter and cylinder rotation speed significantly affect the rasping capacity. Likewise teeth diameter also significantly affect on starch percentage and starch losses in waste. Meanwhile, cylinder rotation speed and the interaction of the two factors have no significant effect on the starch percentage and starch loss in waste. The highest performance was obtained at the condition of teeth diameter 3 mm with cylinder rotation speed of 2500 rpm. The performance of the machine at the condition were (a) rasping capacity 2282 kg h-1, (b) starch percentage 33.02 %, (wb), (c) starch loss in waste 8.77 %.

RANCANG BANGUN ALAT PERONTOK LADA MODEL AKSIAL

<p><strong>Design of axialflow thresherfor pepper</strong></p><p><strong></strong>The pepper threshing practice has been carried out using traditional method in which the pepper berries are usually trampled. This method is neither efficient nor higienic, and it also causes high losses of the berries. To overcome those problems, an experiment was carried out to make an axial flow thresher. The experiment was conducted at Research Institute for Spice and Medicinal Crops from April to December 1999. The experiment consisted of three steps, namely designing, constructing and testing. The objective of testing was to determine the optimum operation condition of the thresher. The testing was designed as a completely randomized complete design with three replications. The raw material for testing was pepper berries (Lampung Daun Lebar variety) of 8 - 9 month old. The result showed that the optimum condition for threshing process was 300 rpm cylinder rotation, with the spike separation process using 7.5° sieve angle. The performance of pepper thresher on that condition was : threshing eficiency 98.55%, spikes separation eficiency 89.22%, berries on spikes outlet 5.20% and berries damage 6.30%. The capacity of thresher was 260.56 kg raw material/hour. The operational cost was Rp 27.28/kg raw material, lower than that of the traditional threshing method (Rp 50/kg raw material).</p>

Investigation of universal conditions of stability of thermal expansion system of steam turbines to external actions

The analysis of various designs (both traditional and alternative) for outboard bearing housing joints with cylinders of steam turbines of medium and high power. Taking into account the identified similarities in the interaction of elements of the considered structures, a generalized kinematic model of the thermal expansion system of a steam turbine is presented. In the assumed model, the thermal expansion system is presented in the form of a multi-link hinged system consisting of one or more “basic” modules. Based on the developed model, the stability conditions (the absence of self-braking on the guiding longitudinal keys) against external influences are studied for the thermal expansion system of a steam turbine. According to the simulation results, it is shown that the magnitude of the turbine cylinder rotation angle change relative to the bearing housing in the junction must be limited. It was revealed that for stability of a system with one outboard bearing housing, it is sufficient that the maximum rotation angle at the junction of the turbine cylinder and the bearing housing does not exceed the maximum rotation angle of the bearing housing relative to the longitudinal keys. For stability of a system with several sequentially moving outboard bearing housings (multi-cylinder turbine), it is necessary that the limiting angle of rotation at all junctions of the turbine cylinders with bearing housings does not exceed the value of the smallest limiting angle of rotation for all bearing housings. The results of the study can be applied in the design of new steam turbines and in the reconstruction of thermal expansion systems for equipment in operation.

Method for Collecting Pasture Ticks by Cylinder-Shaped Drags

The purpose of the research is developing a method to collect pasture ticks where their number is small. Materials and methods. The work was done in 2013–2016. The patent search was conducted according to the task and the search schedule. We found sufficient literature sources and protection documents on the investigated issue. Investigational studies were performed to design an instrument to collect pasture ticks. Results and discussion. A method was developed to collect pasture ticks where their number is small. In order to do this, an instrument was designed which had a cylinder shape and was covered with a cloth called a drag. A rod was placed through the cylinder axle, having its ends connected to each other with a cord to drag the cylinder on the grass. Cylinder rotation when dragged through the grass brings the cloth in contact with ticks without being displaced in relation to one another. A patent of the Russian Federation was obtained under number No. 2544088 “Method for Collecting Ticks”.

Интенсивность выделения зерновок основной культуры из зерносмесей с длинными примесями

Представлены результаты экспериментальных исследований интенсивности выделения зерновок основной культуры из зерносмеси по всей длине овсюжного цилиндра с интервальной оценкой процесса в зависимости от исходной засорённости, подачи, положения выводного лотка и скоростного режима работы триера. Установлено, что исходная засорённость влияет на процесс выделения только при малых подачах зерносмеси в триер до 1,5 т/ч. С увеличением подачи влияние роста примесной засорённости сглаживается увеличением числа циркулирующих слоёв зерносмеси в сегменте. При подаче 1,36 т/ч рабочая поверхность ячеистого цилиндра используется частично. В случае 95го уровня выделения зерновок основной культуры используется до 51,7 длины цилиндра. С ростом подачи до 2,9 т/ч доля используемой части цилиндра достигает 95,4 при максимальном (40) угле подъёма верхней кромки передней стенки выводного лотка и скорости вращения цилиндра (35 об/мин). Увеличение скорости до 40 об/мин приводит к непропорциональному росту интенсивности процесса выделения (в 1,5 раза) изза инерционного удержания контактирующего слоя и последующего его выброса в выводной лоток. При изменении зазора между лотком и внутренней поверхностью цилиндра от 10 до 20 мм интенсивность процесса увеличивается на 11,7.The results of experimental researches of the intensity of the selection of bruchids of the main crop from the grain mixture along the entire length of the oat cylinder with an interval assessment of the process depending on the initial foreign matter, feed, position of the output tray and the speed mode of the sifting cylinder are presented. It was established that the initial weediness affects the selection process only at low feeds of grain mixture into the sifting cylinder up to 1.5 t/h. With an increase in feed the effect of the growth of impurity weediness is smoothed out by an increase in the number of circulating layers of grain mixture in the segment. When feeding 1.36 t/h the working surface of the alveolar cylinder is partially used. In the case of a 95 level of isolation of bruchids of the main crop up to 51.7 of the cylinder length is used. With a feed increase of up to 2.9 t/h the proportion of the used part of the cylinder reaches 95.4 with a maximum (40) angle of climb of the top edge of the leading wall of the output tray and cylinder rotation speed (35 rpm). An increase in speed to 40 rp/m leads to a disproportionate increase in the intensity of the separation process (1.5 times) due to the inertial confinement of the contact layer and its subsequent discharge into the output tray. When changing the gap between the tray and the bore area of the cylinder from 10 to 20 mm, the intensity of the process is increased by 11.7.

Operational performance and losses in mechanized soybean harvesting as a function of field shape

Information on the capacity, operational efficiency, and performance of the harvester is very important in the management of agricultural mechanized systems, influencing decisions made with the aim of optimization. This study aimed to evaluate times, movements, and quality of mechanical soybean harvest operations in different shapes of the plots. Operational performance parameters of the harvester and variables representative of the agronomic aspects of the crop were used as indicators through statistical process control tools. Mechanized harvesting was carried out at a farm located in Uberaba, Minas Gerais, and the experimental design was completely randomized, with 18, 28, and 24 repetitions in irregular, rectangular, and trapezoidal fields, respectively. The activities of the harvester (harvest, unloading, handling, and climate charts) were monitored. The indicators of quality for harvester performance were: forward speed, engine and cylinder rotation and concave opening. The losses were determined: on the platform, internal mechanisms, total and in relation to productivity. The managerial efficiency and shunt time presented better results for the trapezoidal and rectangular section, respectively. All quality indicators evaluated were within the limits of statistical control, characterizing quality and reliability of the soybean harvesting operation.