One-step fabrication of soft calcium superhydrophobic surfaces by a simple electrodeposition process

We investigated a one-step method for calcium superhydrophobic surface preparation and researched the formation process of loose, flower-like microstructures. Also, we found that the pressing force strongly impacts the dynamics of water droplets.

ASPECTS OF BRAKING EFFICIENCY CRITERIA FOR FREIGHT WAGONS UNDER THE LATEST RULES OF HOST 34434-18

The paper deals with the analysis of the braking efficiency criteria for freight trains formed with wagons that have increased axle load up to 294.3 kN (30 ts) when moving at speeds up to 120 km/h inclusive. Increasing the efficiency of freight trains by increasing the technical and economic performance of cars by increasing the axial load to 294.3 kN (30 ts) and train speeds up to 160 km/h led to the development of technical requirements and rules for braking systems set out in HOST 34434-18. According to the new rules and requirements, the following are accepted as criteria for the braking efficiency of freight wagons, that is, up to the maximum values of the braking distances of the freight train on the site in the specified intervals of speeds of axial loads; calculated coefficients of force of pressing of composite blocks on wheels at braking; the pressing force of the composite pads on the axis in terms of cast iron pads. The calculation of the maximum allowable value of the braking distance of the freight train is performed based on the actual pressing forces and the actual friction coefficients. The paper shows that the specific braking forces obtained using the actual pressing forces exceed the calculated specific braking forces using the calculated coefficients. Based on the above-mentioned, it is concluded that the braking efficiency criteria with reference to the maximum allowable values of the braking distances and the calculated coefficients of the pressing force have a significant discrepancy between each other. It is proposed to use the actual pressure force coefficients instead of the calculated coefficients to assess the braking efficiency of the freight train. The paper presents the permissible values of the actual force values of pressing the pads on the wheels for wagons with axial load (230.5 - 294.3) kN at speeds up to 120 km/h inclusive, for which the braking distance criterion of the freight train is observed. Key words: criterion, braking efficiency, freight train, axial load, braking distance, specific braking force, calculated coefficients, actual coefficient.

Piezoelectric response of aligned carbon nanotubes depending on sublayer material

The results of experimental studies of the effect of the sublayer material on the piezoelectric response and sensitivity to mechanical deformations of aligned carbon nanotubes (CNTs) are presented. It is shown that the highest piezoelectric response (136 nA at a pressing force of 4 μN) and best sensitivity are demonstrated by CNTs grown on a Mo sublayer. This dependence is probably due to the geometric parameters of CNTs and the structure of the CNT array as a whole. The results obtained can be used to develop energy-efficient nanogenerators based on CNT arrays.

Strength of multilayer metal joints «shaft-sleeve-hub» of rotorcrafts obtained by plastic deformation

Metal multilayer joints are used in the production and repair of transmission parts and control systems of rotorcrafts with intensively wearing surfaces in the form of smooth closed cylindrical and conical holes. The article describes two types of connections: rolled sleeve - hub and shaft - rolled sleeve - hub. The adhesion strength of the joints depends on the frictional forces that prevent the sleeve from displacing relative to the hub. The traction strength is determined by measuring the pressing force and the torque. It depends on the relative tension. An increase in the force of pressing the joint occurs with an increase in the relative tension of mandrel, in proportion to the hardening of the material. The smaller hub wall thickness leads to the more active effect of its springback to the foundation of contact pressure and an increasing of the traction force. Experiments have shown that the forces and moments of traction depend on the angle of the intake cone and the width of the cylindrical tape of the mandrel.

Study on the Rotor Strength of High-Speed Permanent Magnet Motor Considering the Influence of Assembly Pressing Force

In engineering application, the hot press assembly technology is often used to improve the stability of the rotor structure, but the conventional design methods cannot effectively evaluate the influence of this process on the rotor strength, which easily causes the rotor strength to exceed its safety margin range, and seriously it will lead to the failure of the rotor structure. This paper takes the cylindrical magnet surface-mounted high-speed permanent magnet synchronous motor rotor as the research object. Firstly, the influence of the assembly pressing force on the rotor stresses and interference is analyzed; then, comprehensively considering the assembly pressing force, speed and temperature, the rotor strength’s design method with high structural stability is proposed. Finally, based on the proposed method, the rotor strength of a 100 kW/30,000 rpm high-speed motor is designed, and the feasibility of the design is verified by over-speed experiment.

Development of a Spoon Motion Navigation Algorithm for the Mealtime Assistant Simulator

In aging society like Japan, maintaining the quality of life (QOL) is an important objective. The oral cavity has various significant functions that contribute to the QOL. Elderly people are susceptible to the swallowing disorders owing to various factors associated with advancing age. In such cases, mealtime assistance can provide elderly persons appropriate eating situations. Thus, mealtime assistance skills are essential for students in nursing and caregiver education. Recently, simulation education has attracted attention as an effective educational process for nursing and caregiver students before their clinical practice in a hospital or care house. In this educational process, a patient model that mimics specific symptoms called the simulation model, is used to learn the symptoms and its care process in the same clinical environment as actual. We have attempted to develop several oral care simulation models, and we have earlier developed a prototype of mealtime assistance simulation model. This simulation model had a tongue model with a sensor system to detect spoon motions, and its fundamental functions were evaluated via spoon detection experiments. Based on the earlier achievements, in this study, we develop an evaluation system of feeding skill using a spoon. The pressing force and position by spoon on the tongue model were estimated by transfer functions derived from experiments. In addition, we developed an algorithm that leads students’ spoon position and pressing force in the correct position.

Hydraulic Pipe Bending Machine

The process of pipe bending finds its importance in many industries, instruments, fluids transportation etc. The aim of this research is to design and fabricate a hydraulic jack-based pipe bending machine which has ability to bend pipes used at gas supply industry, while keeping in mind the requirements of a good pipe bending machine to provide high quality bends without defects but at the cost lesser than the existing pipe bending machines available in the marketplace. The fabricated pipe bending machine works on the principle of press bending method to perform the bending operation. The design of the proposed pipe bending machine is based on essential parameters of bending process such as radius and angle of the bend, diameter and thickness of the pipe. The single acting hydraulic jack of 16000 KG load capacity is used to apply the required pressing force to bend a circular pipe having the outer diameter ranging from ½ inch to 2 inches.

Effects of press-forming parameters on the dimensional stability of paperboard trays

The dimensional stability of press-formed paperboard trays was investigated during heating and cooling of trays packed with oatmeal. Female mold tool temperature, dwell time, pressing force, and blank holding force were altered in the press-forming of the trays to observe their impacts on the dimensional stability. Dimensional measurements of the trays showed reduced tray width, and the trays exhibited distortions on the tray flange and outer wall. The results showed smaller effects on the tray length, parallel to the machine direction of the material. Improved dimensional stability of the trays was found with a 180 °C female mold tool temperature, a 600-ms dwell time, a 150-kN pressing force, and a 1.44-kN blank holding force. The optimal press-forming parameters were concluded to enhance bonding of the paperboard fibers during the press-forming. The optimization of the press-forming parameters was found necessary to reduce the observed negative response of the material to the challenging environmental conditions in the production of prepared food.

DEVELOPMENT OF A HEAT-DRIVEN DEVICE FOR MOLDING LARGE-SIZED CONCRETE PRODUCTS

Устройство с тепловым энергоприводом для прессования является разновидностью импульсных устройств. Оно позволяет значительно снизить себестоимость прессуемых железобетонных изделий. Для обеспечения высокой мощности устройства для прессования и уменьшения его габаритных размеров и металлоемкости в его конструкции используется тепловой энергопривод внутреннего сгорания. Существующие прессы для прессования бетонных изделий большой мощности конструктивно сложны и дороги. Поэтому прессование применяют в основном при формовании штучных бетонных изделий небольшого размера. Разработан новый вид устройства для прессования крупногабаритных бетонных изделий. Для выполнения этой цели сделано устройство с тепловым энергоприводом для прессования крупногабаритных бетонных изделий, обеспечивающее высокую прочность этих изделий. Разработанное устройство имеет высокую производительность. Получены зависимости для определения энергосиловых параметров данного устройства, а также необходимой величины давления топливной смеси, обеспечивающей осуществление процесса прессования. В частности, для прессования бетонной плиты площадью 1мвполне достаточно давления топливной смеси 0,9 МПа. При этом давление и усилие прессования составляют: P = 11,7 МПа При увеличении давления топливной смеси до 2 МПа усилие прессования достигает 20 МН, что вполне достаточно для прессования крупногабаритных бетонных изделий A device with a thermal power drive for pressing is a type of impulse devices. It allows one to significantly reduce the cost of compacted reinforced concrete products. To ensure high power of the device for pressing and to reduce its overall dimensions and metal consumption, a thermal energy drive of internal combustion is used in its design. Existing presses for molding concrete products of high power are structurally complex and expensive. Therefore, pressing is used mainly in the formation of small-sized concrete pieces. This article is devoted to the development of a new type of device for pressing large-sized concrete products. To achieve this goal, we developed a device with a thermal power drive for pressing large-sized concrete products, which ensures the high strength of these products. The developed device has a high performance. We obtained dependences for determining the power parameters of the device, as well as the required pressure of the fuel mixture, which ensures the implementation of the pressing process. In particular, for pressing a concrete slab with an area of 1 m, a fuel mixture pressure of 0.9 MPa is sufficient. In this case, the pressure and the pressing force are: P = 11,7 МРа , With an increase in the pressure of the fuel mixture to 2 MPa, the pressing force reaches 20 MN, which is quite enough for pressing large-sized concrete products

Study of cylindrical brush wear effect on its elastic characteristics, on required pressing force and on pressure at the outlet of hydraulic pneumatic accumulator for controlling position of chipping working body

Introduction. The article is devoted to a current issue of improving the quality of road surface cleaning and increasing the resource of brush working equipment. Improving the quality of cleaning and the resource of the brush working equipment will reduce the cost of operating a communal machine. In the process of operation, the pile of the cylindrical brush is worns out, while its elastic characteristics change, which is reflected in the required pressing force to maintain the most favorable value of the width of the contact spot from the condition of ensuring high quality cleaning and minimal intensity of pile wear.Materials and methods. The results of studies of the interaction of the pile of a cylindrical brush with the surface to be cleaned are presented at various degrees of wear of the brush pile. The research results are presented in analytical and graphical forms. The calculations were carried out using the Microsoft Excel software product and the Mathkad software environment for mathematical calculations.Results. The paper shows the dependence of the degree of wear of the pile of the brush working equipment on the actual radius of the cylindrical brush. The relationship between the width of the contact spot and the deformation of the cylindrical brush at different degrees of wear and tear is shown as a graph.The influence of the degree of wear on the elastic characteristics of the brush working equipment is considered. The dependences of the average stiffness coefficient on the degree of wear of the pile of a cylindrical brush, as well as the required pressing force on the degree of wear at different values of the width of the contact patch of the cylindrical brush are given.