Rancang Bangun dan Uji Kinerja Mesin Pembersihan dan Pengayakan Tipe-Grizzly Untuk Beras

Abstrak. Penelitian ini bertujuan untuk mengembangkan mesin pembersih dan pengayak tipe grizzly untuk beras sekaligus menguji kinerja mesin. Penelitian terdiri atas perancangan, perakitan, dan evaluasi kinerja mesin. Mesin yang dikembangkan memiliki 6 (enam) komponen utama, yaitu sumber dan transmisi tenaga putar, lubang pemasukan, unit pembersih beras, unit pengayak beras, lubang pengeluaran, dan kerangka mesin. Penelitian dilakukan menggunakan 3 (tiga) percobaan putaran, L (lambat), S (sedang), dan C (cepat) untuk mendapatkan data dari parameter pengukuran seperti kapasitas kerja, kecepatan putar mesin, laju isapan udara pada unit pembersih, slip putaran puli, dan persentase kehilangan bahan. Pada percobaan putaran L-S-C, yaitu 1654, 1817, dan 1979 rpm, menghasilkan laju isapan udara adalah 7,04, 7,79, dan 8,50 m/s. Slip putaran puli terjadi pada pulli 4 dengan nilai 3,27% tanpa sampal dan 1,70% dengan sampel; puli ini bertugas untuk menggetarkan ayakan grizzly 10-mesh. Kapasitas kerja pada 3 percobaan putaran (L-S-C) berturut-turut adalah 78,5, 81,6 dan 146,7 kg/jam. Pemisahan optimal dedak terjadi para percobaan putaran C sendangkan pemisahan menir terjadi pada percobaan L. Persentase kehilangan bahan tertinggi terjadi selama terjadi penurunan kecepatan putar yang mengakibatkan penurunan efektivitas kerja mesin.Design and Performance Test of Cleaning and Gryzzly-Type Sieving Machine for Rice Abstract. This research aimed to develop and a rice cleaning and grizzly-type sieving machine which also evaluates its performance. It consisted of designing, assembling, and performance evaluating of the machine. The desired machine was developed in six main components, i.e., power source, hopper, rice cleaner, rice siever, outlets, and machine frame. The research used three rotational speed treatments (Slow-Middle-Fast or L-S-C rotations) for data collections, whereas the parameters of performance testing consisted of work capacity, engine rotation speed, airflow rate, pulley rotational slip, and grain loss percentage. Engine rotation speeds at L-S-C treatments are 1654, 1817, and 1979 rpm and resulted in 7.04, 7.79, and 8.50 m/s, respectively, for airflow rates produced by the suction from a blower. The most significant rotational slip is occurred at Pulley-4 resulted in 3.27% (operating without samples) and 1.70% (operating with samples); this pulley transmitted rotational power to vibrate the 10-mesh grizzly sieve. The work capacities at L-S-C rotational treatments were 78.5, 81.6, and 146.7 kg/h, respectively. The optimal separation of brans was at C-rotational treatment, while the optimal separation of groats was at L-rotational treatment. The high percentage of grain loss occurred along with a reduction in speed that made the machine work ineffectively.

Effect of rotational slip on the physical parameter in a micropolar fluid flow past a stretching sheet

Micropolar fluid flow studied in this paper is influenced by microstructural slip. The flow is directed by a scheme of Partial Differential Equalities. These Partial Differential Equalities are then converted to nonlinear set of Ordinary Differential Equalities via boundary layer conversions. MATLAB bvp4c built in code is taken into account to resolve the leading set of ODEs, along with the initial-boundary settings. Hydro dynamical and thermal boundary layer outlines are considered and deliberated and the results are confirmed by linking with available literature in the classical case. Microstructural slip effects are shown on the Nusselt number and skin-friction coefficient. This model can better predict the effects and characteristics of rotational slip. Specifically, it is predicted from the tabular and graphical results that the rotational slip affects the boundary layer thickness when second-order translational slip disappears. It is important to mention that augmenting the standards of Prandtl number and radiation constraint declines the fluid temperature in the nonappearance and existence of microstructural slip. Moreover, increasing the values of magnetic parameter enhances the fluid temperature in presence as well as in absence of microstructural slip.

Anti-Slip Gait Planning for a Humanoid Robot in Fast Walking

Humanoid robots are expected to have broad applications due to their biped mobility and human-like shape. To increase the walking speed, it is necessary to increase the power for driving the joints of legs. However, the resulting mass increasing of the legs leads to a rotational slip when a robot is walking fast. In this paper, a 3D three-mass model is proposed, in which both the trunk and thighs are regarded as an inverted pendulum, and the shanks and feet are considered as mass-points under no constraints with the trunk. Then based on the model, a friction constraint method is proposed to plan the trajectory of the swing leg in order to achieve the fastest walking speed without any rotational slip. Furthermore, the compensation for zero-moment point (ZMP) is calculated based on the 3D three-mass model, and the hip trajectory is obtained based on the compensated ZMP trajectory by using the preview control method, thus improving the robot’s overall ZMP follow-up effect. This planning method involves simple calculations but reliable results. Finally, simulations confirm that the rotational slip is avoided while stable and fast walking is realized, with free joints of the waist and arms, which then could be planned for other tasks.

Оползневый риск в горных районах

Landslide is a major geological hazard, which poses serious threat to human population and various infrastructures. Landslides occur very often together with other natural disasters such as earthquakes, floods or snow melting and volcanoes that play role of triggering mechanism for landslides. Mountainous areas are vulnerable to landslides and have also been affected by earthquakes. Mountainous and coastal areas are the most affected regions. Landslides cause huge damage in the world and kill many people each year. Paper is devoted to landslides research on the base of risk analysis, assessment, management and reduction concept. Landslide Risk Management is seen as a series of events leading to landslides risk reduction and avoiding. It includes landslides monitoring, landslide forecast, engineering works, slopes strengthen, insurance and others. Paper also considered India, China and Russia case studies including Kolka disaster on 20 September 2002 and other related disasters. Kazbek volcanic center is characterized by the complex interrelationship of various hazardous geological processes. Disasters of 2002 and 2014 caused by icerock fall govern importance of investigation of the area. The network recorded a collapse of the mass of ice and rocks in the region of the Devdorak glacier on May 17, 2014 and the movement of the formed stoneice avalanche. In India, the Himalayas are prone to landslides, particularly n monsoon season, from months of June to October. Various types of landslides occur in Himalayas, including block slumping, debris flow, debris slide, rock fall, rotational slip and slump. Generally landslides are triggered by heavy or prolonged rainfall. Landslides cause severe damage to lives and property while also causing disruption in communication networks and movement of traffic. Оползни представляет собой серьезную геологическую опасность, создающую угрозу для населения и различных объектов инфраструктуры. Оползни часто сопровождают другие стихийные бедствия, такие как землетрясения, наводнения, таяние снега и вулканические процессы, которые играют роль механизма запуска оползней. Горные районы, пострадавшие от землетрясений также уязвимы для оползней. Горные и прибрежные районы являются наиболее пострадавшими регионами. Во всем мире оползни наносят колоссальный ущерб и влекут за собой человеческие жертвы. Статья посвящена исследованию оползней на основе концепции анализа, оценки, управления и снижения рисков. Управление рисками рассматривается как серия мероприятий, ведущих к снижению и предотвращению риска оползней. Они включают в себя мониторинг оползней, прогноз оползней, инженерные работы, укрепление склонов, страхование и др. Рассмотрены примеры исследований Индии, Китая и России, включая Колкинскую катастрофу 20 сентября 2002 года и другие связанные с ней катастрофы. Казбекский вулканический центр характеризуется сложной взаимосвязью различных опасных геологических процессов. Бедствия 2002 и 2014 гг., вызванные падением ледяных скал, определяют важность исследования местности. Сеть зафиксировала обвал массы льда и камней в районе ледника Девдорак 17 мая 2014 года и движение образовавшейся ледовокаменной лавины. В Индии Гималаи подвержены оползням, особенно в сезон муссонов, с июня по октябрь. В Гималаях встречаются различные типы оползней, в том числе оползни блоков, обломки, оползни, обвалы, проскальзывание и спад. Обычно сход оползней вызван сильными или продолжительными осадками. Оползни наносят серьезный социальный ущерб, вызывают сбои в различных сетях и движении транспорта.

Simultaneous Prevention of Rotational and Translational Slip for a Humanoid Robot

Slip often occurs in humanoid robot walking, especially when the robot walks on a low friction floor or walks fast. Unexpected slip may cause the robot to fall and then sustain damage. In real environments, rotational and translational slip phenomena can happen during biped walking. Previous studies have mainly focused on solving these problems independently. In this paper, we propose strategies for simultaneous rotational and translational slip prevention based on a three mass model, which takes into account the effect of the swing leg. The rotational slip is prevented through a bionic walking pattern generator which mimics the yaw moment compensation mechanism of a human. The translational slip is eliminated through a novel reaction force ratio reduction control with the compensation of CoM (center of mass) acceleration. The effectiveness of the presented strategies is validated by simulations and experiments with an actual humanoid robot.

Iron-oxide nanostructures with emphasis on nanowires

This article examines the properties of iron-oxide nanostructures, with particular emphasis on nanowires. It begins with an overview of iron-oxide nanostructures and nanowires, followed by a discussion of the synthesis of aligned ?-Fe2O3 nanowires and nanosheets by a simple thermal oxidation route. It then describes the preferential bending of [110] grown ?-Fe2O3 nanowires about the C-axis and quantitative estimation of nanowire alignment using X-ray diffraction and grazing incidence X-ray diffraction. It also considers the growth mechanism of ?-Fe2O3 nanowires and nanosheets, different nanowire morphologies, rotational slip in ?-Fe2O3 nanosheets, and the influence of local environment and substrate microstructure on nanowire growth.

Rotational Slip Flow in Coaxial Cylinders by the Finite-Difference Lattice Boltzmann Methods

Recent studies on applications of the lattice Boltzmann method (LBM) and the finite-difference lattice Boltzmann method (FDLBM) to velocity slip simulations are mostly on one-dimensional (1D) problems such as a shear flow between parallel plates. Applications to a 2D problem may raise new issues. The author performed numerical simulations of rotational slip flow in coaxial cylinders as an example of 2D problem. Two types of 2D models were used. The first were multi-speed FDLBM models proposed by the author. The second was a standard LBM, the D2Q9 model. The simulations were performed applying a finite difference scheme to both the models. The study had two objectives. The first was to investigate the accuracies of LBM and FDLBM on applications to rotational slip flow. The second was to obtain an experience on application of the cylindrical coordinate system. The FDLBM model with 8 directions and the D2Q9 model showed an anisotropic flow pattern when the relaxation time constant or the Knudsen number was large. The FDLBM model with 24 directions showed accurate results even at large Knudsen numbers.