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Effect of the Interfacial Slippage on the Moving Surface in a Hydrodynamic Step Bearing
Get PDFThe effect of the interfacial slippage on the moving surface in a hydrodynamic step bearing is analytically investigated based on the interfacial limiting shear strength model. The calculation results show that when the interfacial slippage occurs on the whole moving surface but is absent on the whole stationary surface, the load-carrying capacity of the bearing is independent on the sliding speed but is intimately dependent on the contact-fluid interfacial shear strength on the moving surface, and the carried load of the bearing is normally heavily reduced as compared to that calculated from conventional hydrodynamic lubrication theory especially for high sliding speeds; The friction coefficient of this mode of bearing is significantly higher than that of the conventional hydrodynamic step bearing for a high sliding speed, but the case is opposite for a low sliding speed. The results show the potential application value of this mode of bearing for reducing the friction at a low sliding speed or the necessity of preventing the occurrence of the interfacial slippage on the moving surface in a hydrodynamic step bearing at a high sliding speed
Analysis and Design of Rehabilitation Device in Sensory Integration Therapy for Autism Children
Get PDFA group of complex disorders in terms of brain development is known as Autism Spectrum Disorder (ASD). The rehabilitation device playing vital roles in this institute which provide crucial assistance in the process of helping the autism people. Nowadays, the development of the technologies has led to the integration of the rehabilitation device with technology to sophisticating the function of the device. In this study, the integration of the electrical and the electronic technologies will be implemented for the purpose of attracting the learning desire of the autism children. The performance of autism children in the aspect of ‘attention’ will be identified and discussed. Overall data that had been collected showed an improvement in the performance of both of the autism children. Hence, autism children showed that they had improved their performance by paying attention on the task that had been given and less doing unnecessary things that can keep their attention away
Microstructures and Metallographic Characterization of Superalloys
Get PDFSuperalloys are metallic alloys with specific microstructures and atoms in solid solution allowing good mechanical and chemical properties at high temperature, typically higher than 1000°C. They present many different types of {matrix – precipitates} combinations which can be characterized at each step of their elaboration, by specifying the chemical compositions and the crystalline network of the phases present. After test on a sample (laboratory scale), or after the deterioration in service of a component leading to its replacement by a new one (industrial scale), the superalloys constituting these pieces are often usefully examined. This aims to specify the changes occurred in their microstructures as well as in their surface or sub-surface, due to the endured thermal, mechanical and chemical solicitations. These characterizations can be simply done using basic low-magnification optical microscopic examinations. Other means such as electronic microscopy and other advanced apparatus may be usefully involved for further investigations. After a brief history about superalloys, an overview of the phenomenological aspects of their mechanical and chemical solicitations during their use at high temperature, the metallographic techniques which are usually employed to characterize them are presented and illustrated in the case of a chosen family of superalloys
Maintance by Water-Cleaning and Efficiency Reduction of PV Panels
Get PDFWith the increase in the use of solar energy, both in civil and industrial environments, the problem of maintenance of photovoltaic panels becomes extremely important. In this work attention is restricted to the problem of cleaning and safety conditions of the photo-voltaic (PV) panels and a brief review of main effects determining their efficiency reduction are reported. The discussion related to problems and unsafe functioning conditions concludes this paper
Investigation on the Influence of the Interfacial Slippage on the Whole Moving Surface in an Inclined Fixed Pad Thrust Slider Bearing
Get PDFThe influence of the interfacial slippage on the whole moving surface on the carried load and friction coefficient of an inclined fixed pad thrust slider bearing is analytically investigated. The calculation results show that the carried load of this mode of bearing is normally much lower than that of the conventional inclined fixed pad thrust slider bearing, while the friction coefficient of this mode of bearing is significantly higher than that of the conventional bearing, when the operating condition is the same. With the reduction of the contact-fluid interfacial shear strength on the moving surface, the performance of this mode of bearing is worsened. These results suggest the necessity of preventing the interfacial slippage on the moving surface in an inclined fixed pad thrust slider bearing
Coupled Modelling of ZrO2/α-Zr(O) Layers Growth under Thermal and Mechanical Gradients
Get PDFThe oxidation process of a nuclear reactor fuel rod clad made of zirconium is simulated. It is assumed that the oxygen is transported by anionic diffusion in the zirconia layer (ZrO2). Part of this oxygen reacts at the interface between the zirconia layer and the metal, while the rest diffuses in the oxygen-enriched metal volume (a-Zr(O)) to the core of the metal by an interstitial mechanism. The model is based on the thermodynamics of irreversible processes and takes into account the influence of driving forces on the oxygen migration in the metal such as the oxygen concentration gradient, the temperature gradient [1] and the mechanical stress gradient [2]. The growth of both ZrO2 and a-Zr(O) layers are simulated using the finite element software CAST3M. This model has been applied on an axisymmetric geometry by imposing a heat flow on the fuel side and a constant temperature on the waterside of the clad. The differences obtained in the inner and outer sides of the nuclear clad concerning the oxidation kinetics and oxygen distribution are related to some coupling parameters. Several values of those parameters are used in the simulations to highlight their influence on the oxidation behavior. Thus, we show that negative values for the heat of transport, which relates the gradient of ocncentration and the gradient of temperature, give coherent results with experimental observations on oxidation kinetics for both sides of the clad
GC-MS Analysis and Characterization of Bio-Oil from Sweet Potato Peel - A Putative Bio-Fuel
Get PDFDue to the excessive oil consumption alongside with its possible depletion and the need to find new sources of products with reduced ecological footprint, urges to conduct the research towards to new processes using biomass, especially residues, as sources of raw materials. The acid liquefaction catalyzed by the p-toluene sulfonic acid of sweet potato peel waste was conducted under mild conditions leading to a bio-oil with a conversion of 85 %. The products were analyzed by ATR-FTIR, SEM, GC-MS and elemental analysis. The results have demonstrated the liquefaction of sweet potato peel is achievable and affords a high carbon content bio-oil composed mainly by carbohydrate compounds and esters showing that the liquefied products can be envisaged as a chemical platform for several uses, in particular as biofuel due to its esters content
Interventional Status Awareness Based Manipulating Strategy for Robotic Soft Endoscopy
Get PDFTraditional soft endoscopy is operated with naked eyes and use of hands. Robotic soft endoscopy frees the hands of endoscopists, which reduces the labor-intensity and complexity of operation and improves the operational accuracy of endoscope, but it¢‚¬„¢s hardly to be reliably performed because the operator lacks of situational awareness of endoscopic interventional status when the hands are detached from the endoscope. This paper first presents a method to perceive the interventional status of endoscope based on image processing, the interventional status includes insertion length and velocity. A manipulating strategy was designed according to the perceived endoscope interventional status and construction parameters of dual robotic arms in order to achieve reliable interventional endoscopy. Human phantom experiments are carried out to verify the effectiveness and feasibility of the proposed interventional status awareness method and manipulating strategy. The results show that the robotic soft endoscopy can be well performed with the ability of interventional status awareness and coordinated manipulation of dual arms. The perceived insertion length indicates the position of the tip of endoscope in human body and the designed manipulating strategy is effective in endoscopic shape retention and torque transmission
Robotization as One of the Prospects for Electromobility in Belarus
Get PDFIn order to create a competitive and resource-efficient transport system, the transport policy of the European Union provides for the achievement by 2030 of almost zero carbon dioxide content in the exhaust gases of vehicles used in large urban centers, and by 2050 the phasing out the use of cars, working on traditional fuels. The Republic of Belarus has a high scientific and sufficient industrial potential to participate in the process of promoting electric mobility, taking into account the use of robotics.
JSC "Instrument-Making Plant Optron" developed the working documentation and produced prototypes of typical representatives of the line of personal electric vehicles. However, the ongoing research focused on the creation of a preventive diagnostic system for the electric motorcycle, developed by Belarussian researches and its intelligent on-board system, focused primarily on real-time simulation processes, related specifically to the level of artificial intelligence, and on the implementation of executive level algorithms
Synthesis and Characterization of LaCu0.25Mn0.75O3-δ Nanoparticles Perovskite Materials
Get PDFA spongy black powder of LaCu0.25Mn0.75O3-δ was synthesized by a modified Pechini method in this study. Properties of LaCu0.25Mn0.75O3-δ perovskite were investigated via in situ Fourier transform infrared (FTIR) spectroscopy. X-ray diffraction results indicated obtaining highly crystalline LaCu0.25Mn0.75O3-δ sample with crystallite size was 37 nm. FTIR results confirmed the formation of LaCu0.25Mn0.75O3-δnanoparticles. High-Resolution Transmission Electronic Microscope HRTEM image illustrates that the prepared sample is in the nanoscale with d-spacing equal to 0.13 nm matching the [440] plane of cubic LaCu0.25Mn0.75O3-δ.The optical properties of the obtained samples were investigated and indicated that the prepared sample is in the nanoscale