Papers by Keyword: Device

Abstract: The article describes the design and purpose of a turbopump unit, in particular, the pump body of the liquid rocket engine turbopump unit. The technology and technological equipment for obtaining complex profile holes in the turbopump units body are presented. The design features of technological process and equipment for electrochemical processing are considered. The proposed technology and devices allows to process parts of the liquid rocket engine turbopump unit with special holes.

Abstract: The paper briefly describes the methods for testing soils by triaxial compression. Among the many mechanical characteristics of the soil, deformation and strength properties remain as the main and widely used ones, the determination of which is an important experimental task. In recent years, new test schemes, more advanced designs of instruments and equipment for the study of various soils have been proposed. Like any material, the soil has limited strength, and under certain external influences the soil massifs collapse, as a result of which their individual parts get unlimitedly large displacements. Triaxial soil compression is becoming more widespread in the production of engineering and geological studies to justify the construction projects of various engineering structures. Based on the results of this work, recommendations for the practical application of the obtained soil characteristics for the geotechnical geoinformational database of the city of Nur-Sultan are made.

Abstract: Experimental studies of the influence of the heating temperature on the properties of pipe billets made of titanium alloys OT4 and OT4-1 in the formation of parts for the installation of pipeline systems without a protective atmosphere are presented.

Abstract: Low vision" is a pathological condition caused by an ocular illness in which the visual acuity is 20/70 or less in the better eye and cannot be corrected or enhanced with ordinary glasses (spectacles). Most visually impaired people have some degree of instability, which highlights the need for some help, both for travel and for support in standing. Existing systems are complex, useful, diversified in relation to patient requirements, fixed or mobile, but all require manual use that limits mobility and accessibility. In this research we propose a portable system designed as a structure created by 3D printing of thermoplastic materials and composite materials. Inside of this structure, optimized as an assembly space, the electronic system is designed for guidance and warning actions adapted to the patient with low vision. The system is designed to be easy to use, to have a very low weight and to be adaptable to any anthropometric dimension of patient or mobility space. The thermoplastic and composite materials, as well as the 3D printing technology, allow, for a low weight and an affordable price, to obtain a system that gives more stability and mobility to patients with low vision or blindness.

Abstract: ZnO NWFETs were fabricated with and without Al₂O₃ passivation. This was done by developing a new recipe for depositing the thin film of ZnO. By using a high donor concentration of 1.7 x 10¹⁸ cm^-3 for the thin film, contact resistance values were lowered (passivated device had R_con = 2.5 x 10⁴ Ω; unpassivated device had R_con = 3.0 x 10⁵ Ω). By depositing Zn first instead of O₂, steep subthreshold slopes were obtained. The passivated device had a subthreshold slope of 225 mV/decade and the unpassivated device had a slope of 125 mV/decade. Well-behaved electrical characteristics have been obtained and the passivated device shows field effect mobility of 10.9 cm²/Vs and the un-passivated device shows a value of 31.4 cm²/Vs. To verify the results, 3D simulation was also carried out which shows that the obtained values of sub-threshold slope translate into interface state number densities of-1.86 x 10¹³ cm^-2 for the unpassivated device and 3.35 x 10¹⁴ cm^-2 for the passivated device. The passivated device is suitable for biosensing applications.

Abstract: Improving the efficiency of construction composites is a relevant problem for modern-day material science. One of the ways to solve the problem consists in activating the binders by means of vortex-layer devices. Mathematical transformations produced a formula for calculating the dependency of the number of ferromagnetic-particle collision on the number and velocity of such particles, as well as on the device chamber fill factor. The results obtained by applying the proposed formula differ from D.D. Logvinenko's model by 10% at max. We calculated the impact force, the impulse of the grinding body in the vortex-layer device, as well as the amount of applied energy per unit of mass of the ground material. It was found out that the impact force and the impulse of force were maximized in the test device. At the same time, energy applied over the grinding time necessary to even out the binder dispersion in the vortex-layer device was 2 to 4.8 times greater compared to conventional devices.

Abstract: In this paper we consider different types of working bodies and fillers used in the manufacture of hydro-gas systems of aircraft from thin-walled pipe billets, and also explored the advantages and disadvantages of liquid, fusible, solid, elastic, loose and combined fillers in the deformation of pipe segments by means of distribution, crimping, forming and flexible. As a result of the research, a device for distributing pipe billets along a rigid matrix and a working body made of granular polyurethane and ice, the main advantages of which are: good rheological properties (fast flow); high ductility and viscosity; high ability to transfer pressure throughout the metal zone; ability to withstand high compression load; ease of entry into the workpiece and removal from the finished part; low production costs.

Abstract: A highly sensitive low-doped ZnO nanowire field effect transistor (NWFET) biosensor has been fabricated and measured. The low doped biosensor with NWFET transducer was used to sense charge of the following substances: lysozyme (LYSO), phosphate buffered saline (PBS), bovine serum albumin (BSA). It achieved maximum sensitivity of -543.2 % for the PBS-LYSO protein and 13,069 % for the PBS-BSA protein. These results were achieved because the electrical measurement and characterisation was focused on the charge effect of the LYSO and BSA acting on the ZnO nanowire subthreshold region. The nano-fabrication process is stable and reproducible. The high sensitivity of the ZnO NWFET biosensor can be exploited for selective analyte detection by functionalizing the nanowire surface with antibodies and/or other biomolecular probe molecules.

Abstract: The present article describes the method and devices for material elastic limits and proportionality calculation. This invention is to allow for automation and higher measurement accuracy. Formulas for calculating measurement errors are given. An example of measuring and calculating is described.

Abstract: In this work, the photoelectric properties of ZnO_1-x/graphene heterostructures were investigated. Such ZnO_1-x/graphene heterostructures were constructed from non-stoichiometric zinc oxide (ZnO_1-x) film and graphene by first depositing ZnO_1-x layer through radio frequency magnetron sputtering onto silicon wafers with SiO₂ layer and then transferring graphene via a wet method. It was revealed that such heterostructures could have improved photoelectric properties. Compared with ZnO_1-x films, the absorbance of the ZnO_1-x/graphene heterostructures in visible and near-infrared region was enhanced; and due to the high conductivity of graphene, the photocurrent was significantly enhanced both in dark and under irradiation of a 700 nm light. By calculating the absolute current gain, it was revealed that the fabricated ZnO_1-x/graphene heterostructures would have a higher current gain. Thus, such ZnO_1-x/graphene heterostructures would be promisingly applied in visible light to near-infrared detection devices.