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2021 ◽  
Vol 108 ◽  
pp. 17-22
Author(s):  
Tomáš Zelenka

The article deals with the construction of a geophysical observatory in the town of Fürstenfeldbruck, Bavaria, Germany. The observatory is being built for the Technical university in Munich. The main function of the observatory is to measure changes in the Earth ́s spin rate or, its axes deviations etc., which can occur with physical impulses in a form of, for example, an earthquake or nuclear explosion etc. Measuring such physical phenomena is important and the data is used to adjust navigation of satellites orbiting the Earth. As there were installed unique measuring tools in the building, the construction materials and building process itself has had to be carefully chosen and though through. The observatory is placed underground and has shape of a tetrahedron. The top of the construction is oriented in direction to the Earth ́s centre. To secure the pit the sprayed shotcrete was used and reinforced with AR Glass. To anchor the pit horizontally they also used the AR Glass. After finishing the pit, the central shaft was built and situated vertically from the top of the tetrahedron in direction to the Earth ́s surface and to the top of the tetrahedron base. Under a layer of concrete, there is a PE HD pipe DN 630 in every wall to connect the tetrahedron top with the base tops. There are several concrete shafts situated in each top tetrahedron base and also, at half of the span between the tetrahedron base tops. All these concrete shafts on the ground are interconnected by plinth beam with one another. The plinth beam contains three PE HD pipes DN 140. This type of construction was chosen as there is laser circling in the tetrahedron base, its top, and between tetrahedron top and base. In every shaft there is installed a measuring instrument, which is very sensible when in contact with steel parts. The sensibility to steel was a reason for employing only glass reinforcement GFK in every concrete part of this construction.


2021 ◽  
Vol 892 ◽  
pp. 74-80
Author(s):  
Irvin Barizi Muhammad ◽  
Husaini ◽  
Ali Nurdin ◽  
Akmal Rauzatul ◽  
Edisah Putra Teuku

The screw press is a type of machine press used for extracting crude palm oil from the oil palm’s mesocarp, where its short driveshaft, a mechanical component for transmitting torque and rotation, is often found to be susceptible to failure. Since the initial damage to the short driveshafts in the shaft keyway area is associated with the frequent incidence of shaft failure, this research aimed to discover the root cause of this failure and how to prevent it using visual inspection and stress analysis methods as well as those of the fractography, metallography, chemical composition, and hardness tests. Using the descriptive method to analyse the collected data, the visual inspection and the fractography results of the research indicated that the fatigue crack failure of the short drive shaft in the palm oil screw press machine was caused by the fatigue crack initiation that was safe from stress concentration in its keyway areas. This crack initiation was followed by crack propagation as indicated in beach mark forms. Finally, the ductile fracture observed on the shaft surface was found to have resulted from the continuous rotational motion and the loading and unloading effect of the central shaft driving system.


2021 ◽  
Vol 23 (2) ◽  
pp. 145-148
Author(s):  
Letícia De Barros Rocha ◽  
Ana Leticia Cardoso Pinto ◽  
And´ré De Aguiar Santos Filho ◽  
Byanka Luanne Da Silva Macedo ◽  
Larissa De Cássia Silva Rodrigues ◽  
...  

AbstractAfter a visit to a hydrotherapy laboratory, limited resources for use in lower limbs were noted. For this reason, the goal is to design a water bike from low-cost material. The process took place in three phases: (1) project carried out, (2) prototype construction and (3) bicycle construction. The confection was divided into six parts; the materials used were polyvinyl chloride (PVC) tubes for the construction of sewer system. In addition to PVC materials, other products were used: two plastic pedals; a gel saddle, a seat post, two cranksets, a pipe clamp, a central shaft, two industrial bearings, three 40-millimeter aluminum cylinders and four suction cups. The final product was measured 69 centimeters (cm) in width, 59.05 cm in length; as the seat can be adjusted, the height varies. The prototype ranges from 73 to 102 cm in height and supports up to 85 kilograms (kg). It is concluded that although there is a limitation as to the design of the final product due to the limited formats of the PVC connections and as to the adaptations that must be made so that the final product can support a considerable weight, it is feasible to make a low-cost water exercise bike using PVC as the main material that can be used in the pool. It is noteworthy, however, that this product will still be tested to ascertain functionality as for equipment for clinical practice. Keywords: Hydrotherapy. Low-Cost Technology. PVC Pipes. ResumoApós a visita em um laboratório de hidroterapia denotou-se a limitação de recursos para membros inferiores. Devido a isso, o objetivo é elaborar uma bicicleta aquática de material de baixo custo. O processo se deu em três fases: (1) design realizado, (2) produção do protótipo e a (3) construção da bicicleta. A confecção foi dividida em seis partes; os materiais utilizados foram tubos de Policloreto de vinila (PVC) para esgoto predial. Além de materiais de PVC foram utilizados outros produtos: dois pedais de plástico; um selim de gel, um canote, dois pedivelas, uma braçadeira de tubo, um eixo central, dois rolamentos industriais, três cilindros de alumínios 40 milímetros e quatro ventosas. O produto final teve como medida 69 centímetros (cm) de largura, 59,05 cm de comprimento; como o banco pode ser regulado, a altura varia. o protótipo varia entre 73 a 102 cm de altura e suporta até 85 quilogramas. Conclui-se então que embora haja limitação quanto ao design do produto final por conta dos limitados formatos das conexões de PVC e quanto à adaptações que devem ser feitas para que o produto final consiga suportar um peso considerável, é viável a confecção de uma bicicleta ergométrica aquática de baixo custo utilizando o PVC como material principal e que pode ser utilizada na piscina. Destaca-se, entretanto, que este produto ainda será testado para averiguar a funcionalidade quanto equipamento para a prática clínica. Palavras-chave: Hidroterapia. Tecnologia de Baixo Custo. Tubulações de PVC.


2021 ◽  
pp. 111086
Author(s):  
Lingjie Zeng ◽  
Leqi Tong ◽  
Jun Gao ◽  
Bowen Du ◽  
Changsheng Cao ◽  
...  

2020 ◽  
Vol 20 (3) ◽  
pp. 215-223
Author(s):  
Sanghyun Jun ◽  
Hyungho Lee ◽  
Byungsoo Park

A helical pile is a foundation type that can be constructed to improve the bearing capacity and pullout resistance using a spiral plate affixed to the central shaft of the pile. In the past, piles were applied in formulaic shapes, but based on recent developments of threaded joints, the specifications of a helical pile can be applied depending on the site conditions. In this study, model tests and numerical modeling were performed to analyze the bearing capacity and pullout resistance based on the number, size, and position of the helix, which were the main factors of the helical pile. The bearing capacity and pullout resistance improved as the number and diameter of the helix increased. When the helix was installed near the bottom of the pile, the helical pile showed an excellent performance. In addition, by analyzing the ratio of the increase in the bearing capacity according to the area ratio of the helix as a part of the economic analysis, it is essential to consider the installation position of the helix. Based on the analysis results, it was shown that the helical pile could be improved.


Science ◽  
2019 ◽  
Vol 365 (6455) ◽  
pp. eaaw9144 ◽  
Author(s):  
Long Zhou ◽  
Leonid A. Sazanov

V (vacuolar)/A (archaeal)-type adenosine triphosphatases (ATPases), found in archaea and eubacteria, couple ATP hydrolysis or synthesis to proton translocation across the plasma membrane using the rotary-catalysis mechanism. They belong to the V-type ATPase family, which differs from the mitochondrial/chloroplast F-type ATP synthases in overall architecture. We solved cryo–electron microscopy structures of the intact Thermus thermophilus V/A-ATPase, reconstituted into lipid nanodiscs, in three rotational states and two substates. These structures indicate substantial flexibility between V1 and Vo in a working enzyme, which results from mechanical competition between central shaft rotation and resistance from the peripheral stalks. We also describe details of adenosine diphosphate inhibition release, V1-Vo torque transmission, and proton translocation, which are relevant for the entire V-type ATPase family.


Author(s):  
V. M. Lyatkher

The paper discusses the problem of using the energy of rivers without creating the dams and flooding vast areas and notes that there is a progress in the implementation and development of the ideas of patent in 1931 (the speed of the workers turbine blades is higher than flow rate). The paper gives the diagrams of the new turbines of this type, for example a balanced 6-tier single-blade turbine, turbine-spiral, a balanced twoblades turbine. Moreover, the paper deals with the features free-threaded orthogonal turbines in the streams of the limited width and depth. The most important characteristic of a turbine is the turbine's power factor that is equal to the ratio of the energy of the rotating turbine to the kinetic energy of the flow in the current tube passing through the turbine circuit. There is a possibility of a significant increase in the power of the turbine in comparison with the conditions of use unlimited streams. The increase in turbine power in a straitened flow is associated with an increase in the flow velocity in the turbine on the approach to the rear section of the blades’ track. It is set the requirements of the turbine parameters for maximum power at a given water flow and the permissible level rise in the river. These requirements relate to the certain rules for selecting the number of blades (and solidity) of the turbine, taking into account the permissible increasing in the water level (backup) in front of the turbine. The paper notes the turbines instability at low speed of rotation, describes a turbine design modification that eliminates this drawback. Modification of the high-speed orthogonal turbines is the use of accelerating blades with a cup-shaped cross-section, placed on the route within a diameter 2 times smaller than the diameter of the main (working) blades of the smoothly streamlined profile. It is concluded that all considered variants of turbines for streams with limited cross-section, the design of the blade system may be made rigid, which eliminates the single central shaft (axle), replacing it with a reference semi-shafts.


Author(s):  
S. A. Adegbite ◽  
W. B. Asiru ◽  
M. O. Salami ◽  
C. F. Nwaeche ◽  
K. K. Ebun ◽  
...  

A continuous process power driven gari fryer was designed, fabricated and tested at the Federal Institute of Industrial Research, Oshodi. (FIIRO), Lagos, to fry large quantity of cassava mash using locally available materials. The fryer which consists of major two sections; one to gelatinize cassava mash while the drying of the mash take place in the other section. The essential components of the fryer include feeder, frying troughs, rotating paddle arrangement, central shaft, coupling, top cover, gas burners, discharge sprout, main frame, insulation wall, sprocket and internal combustion engine. In operation, the rotating paddles convey the cassava mash during the gelatinization and drying process from the feeding point to the discharge sprout to obtain finished gari product. At constant speed of 8 rpm, the result showed that the time of frying ranged between 14 minutes to 17 minutes with an output of 83.2 kg/hr while the percentage yield of gari obtained ranged from 52.8% - 74.7%. Thus it is established that the capacity of the fryer is 500 kg per day as against the manual method of frying where 5 kg of gari is obtained within 30 minutes (80 kg/day) for 8 hours frying operation in local cassava processing industry in Nigeria. Hence, this makes the fryer to be suitable for gari production for small to medium scale enterprise.


2019 ◽  
Vol 290 ◽  
pp. 11012 ◽  
Author(s):  
Mihaela Toderas ◽  
Ionela Samuil ◽  
Andreea Ionica ◽  
Marius Olar ◽  
Stefan Militaru

The main problem of former industrial areas with history of mining exploitation is the impact of specific activities both on the environment as well as on the social and economic life of the population. In this context, we talk about the Jiu Valley, a mono-industrial area where significant environmental degradation is observed and which did not benefit from economic diversity policies. The aim of this paper is to identify possibilities for the rehabilitation of the Petrila mining perimeter and its potential use in a touristic circuit that adds value to constructions declared historical monuments, dating back to 1850, such as the central shaft and the skip, the old compressors, treatment and the mechanical workshop.


2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Michele Mari ◽  
Mauro Venturini ◽  
Asfaw Beyene

In this study, we present the results of a two-dimensional fluid-dynamic simulation of novel rotor geometry with spline function which is derivative of the traditional S-shape Savonius blade. A computational fluid dynamic (CFD) analysis is conducted using the Spalart–Allmaras turbulent model, validated using experimental data released by Sandia National Laboratory. Results are presented in terms of dimensionless torque and power coefficients, assuming a wind speed of 7 m/s and height and rotor diameter of 1 m. Furthermore, analysis of the forces acting on the rotor is conducted by evaluating frontal and side forces on each blade, and the resultant force acting on the central shaft. A qualitative representation of the vorticity around the traditional and spline rotor is shown to prove that the novel blade allows less turbulent flow through the rotor.


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