ESTIMATION OF APPLICATION EFFICIENCY OF THE PR30-HVS LEVELER IN DIFFERENT MEASUREMENT CONDITIONS

The article is devoted to comparative analysis of accuracy of horizontal positioning measurement results for different measurement conditions. Performing work of this type refers to a number of applied tasks that require high accuracy of the horizontal arrangement of objects. For the purposes under consideration, laser levelers are often used. Currently, the market offers many models of this type of devices. As a rule, the documents accompanying provide metrological characteristics with an indication of one specific distance, for which the result indicated and, in most cases, the influence of measurement conditions on the error of results obtained is not considered. However, for long distances or difficult operating conditions (rain, dust), a significant increase in the error should be expected due to peculiarities of laser radiation and its transportation in the environment.

Experimental evaluation of the effect of different design conditions on the risk of decay in solid wood exposed to outdoor climate

Wood decay have the greatest impact on in-service wood structural elements. In most cases, decay is associated with excessive accumulation of moisture in the wood. The structural design conditions have an effect on the wood moisture content and this affects the service life of the material. In this study, which involved an experimental trial specifically designed to embrace different structural design conditions, the moisture content evolution in different places affected by different design conditions was evaluated over a period of three years in Madrid (Spain). The effect of protection by eaves, separation from the ground and the vertical or horizontal arrangement of the wood elements on the monthly evolution of the moisture content and decay risk are assessed.

Adapting M2 silicon half-wafers processing on industrial-scale equipment dedicated to 4″ solar technology

Purpose The purpose of this study is to address the issue of technology equipment formerly dedicated to the process of 4- and even 5-inch photovoltaic cells and whose use has become critical with the evolution of silicon wafer size standards (M2–M10). Fortunately, the recent concept of 6'' half-cut cell with its many advantages appears promising insofar as it offers the possibility of further extend the use of costly, still operational process equipment, but doomed to obsolescence. Design/methodology/approach In the background of a detailed Al-BSF process, the authors show how to experimentally adapt specific accessories and arrange 6” half-wafers to enable the upgrade of a complete industrial process of silicon solar cells at a lower cost. Step by step, the implementation of the processes for the two wafer sizes (4” wafers and 6” half wafers) is compared and analyzed in terms of performance and throughput. Findings Globally, the same process effectiveness is observed for both types of wafers with slightly better sheet resistance uniformity for the thermal diffusion carried out on the half wafers; however, the horizontal arrangement of the wafer carriers in the diffusion and the plasma-enhanced chemical vapor deposition tubes limits the thermal balance regarding the total number of cells processed per batch. Originality/value In terms of the development of prototypes on a preindustrial scale, this paves the way to further continue operating outdated equipment for high-performance processes (passivated emitter and rear contact, Tunnel oxide passivated contact (TOPCon)), while complying with current standards for silicon wafers up to M10 format.

Mathematical modeling of the dragline travel mechanism with sliding supports

The results of an analytical study of the walking mechanisms of dragline excavators are presented. The advantages and disadvantages of the hydraulically driven walking mechanism are considered. Constructive changes are proposed in the form of installation of sliding supports and horizontal arrangement of traction hydraulic cylinders on support shoes. A method for calculating the forces acting on sliding bearings is presented, which makes it possible to determine the requirements for the physical and mechanical properties of the sliding bearings material, including the hardness and wear resistance of their working surfaces. Examples of using the mathematical model of a three-bearing walking mechanism with sliding supports, created in the MATLAB Simulink software environment, are shown.

Mathematical Modelling and Operational Analysis of Combined Vertical–Horizontal Heat Exchanger for Shallow Geothermal Energy Application in Cooling Mode

Geothermal heat exchangers (GHEs) represent a buried pipe system, which can be utilised to harness renewable thermal energy stored in the ground to improve the efficiency of heating and cooling systems. Two basic arrangements of GHEs have been widely used: vertical and horizontal. Vertical GHEs generally have a better performance in comparison with the horizontal arrangement, and these systems are particularly suitable for confined spaces. Nevertheless, the main technical challenge associated with GHEs, for either the vertical or the horizontal arrangement, is the performance deterioration associated with an increase in the operation times during summer or winter seasons. In this paper, a combined horizontal-vertical GHE arrangement is proposed to address the current challenges. The combined GHE arrangement can be operated in five different modes, corresponding to different thermal loading conditions. These five operation modes of the combined GHE are analysed based on the transient finite difference models previously developed for the horizontal and vertical arrangements. The simulation results reveal that for the single operation mode (horizontal or vertical only), the vertical GHE performs better than the horizontal GHE due to relatively stable ground temperature deep down. While, for the combined operation mode, the series operations (horizontal to vertical or vertical to horizontal) of the GHE are superior to the split mode. It is found that the effect of the fluid mass flow rate ratio is trivial on the heat dissipation of the split mode GHE. The highest heat transfer rate in the split flow operational mode is rendered by the ratio of the mass flow rate of 40% horizontal and 60% vertical. In addition, the climate condition has more effect on GHE’s performance and the increase of the fluid flow rate it can enhance the amount of energy released by the GHE.

INVESTIGATION OF THE DYNAMICS OF THE ELASTIC-MASS SYSTEM OF THE MOBILE HEARTH OF AN ELECTRIC KILN FOR FIRING THERMALLY ACTIVATED MATERIALS

In article results of research of properties elastic element platform furnace with a movable hearth, the analytical model of motion, characterized by sloping skeletal curve of its amplitude-frequency characteristics. The study of the dynamics of elastic-mass system of the platform with unilateral elastic element in the form of a flattened elastic ring that provides her a strong nonlinearity, it is confirmed that the system does not symmetrical oscillation with peak acceleration values of 5.17 and 1.17 m/S2, corresponding to the extreme provisions of the different platform and four and a half times. It is shown that the horizontal arrangement of the movable hearth of the furnace significantly reduces the sensitivity of its vibrations to changes in the excitation frequency, spring stiffness, friction forces, and other factors that change due to the influence of high temperature and external environmental factors. The effect of vibration transport of bulk material along the horizontal surface of the mobile hearth of the furnace platform in the thermal field of its heating system is confirmed.

Oxygen Consumption in Two Subsurface Wastewater Infiltration Systems under Continuous Operation Mode

In this work, an innovative arrangement of a vertical subsurface flow wastewater infiltration system (SWIS) was studied. The principal objective of this study was to evaluate the oxygen transfer rate (OTR) in two different pilot-scale arrangements of an SWIS. The two pilot plants were composed of four filter beds in series, one with a vertical arrangement of the beds (one over the other) and the other with a horizontal arrangement of the beds (one next to the other). Furthermore, two kinetic models were applied for correlating the COD and NH4+-N concentrations at the inlet and outlet of each treatment step in both pilot plants. The fitting of experimental data to the models allowed the calculation of the areal rate constants. The OTR values obtained were 54.69 g m−2 h−1 and 28.84 g m−2 h−1 for horizontal and vertical arrangement, respectively. These values were considerably higher than those obtained by other authors. The plug flow model describes the behaviour of these SWISs better, and the best fits were achieved for the vertical arrangement. The areal rate constant values obtained in this study were higher than those reported in the bibliography, which indicates a great removal efficiency and therefore lower surface area needed for the treatment.

The Usefulness of Pine Timber (Pinus sylvestris L.) for the Production of Structural Elements. Part II: Strength Properties of Glued Laminated Timber

The paper assessed the feasibility of manufacturing glued structural elements made of pine wood after grading it mechanically in a horizontal arrangement. It was assumed that the pine wood was not free of defects and that the outer lamellas would also be visually inspected. This would result in only rejecting items with large, rotten knots. Beams of the assumed grades GL32c, GL28c and GL24c were made of the examined pine wood. Our study indicated that the expected modulus of elasticity in bending was largely maintained by the designed beam models but that their strength was connected with the quality of the respective lamellas, rather than with their modulus of elasticity. On average, the bending strength of the beams was 44.6 MPa. The cause of their destruction was the individual technical quality of a given item of timber, which was loosely related to its modulus of elasticity, assessed in a bending test. Although the modulus of elasticity of the manufactured beam types differed quite significantly (11.45–14.08 kN/mm2), the bending strength for all types was similar. Significant differences occurred only during a more detailed analysis because lower classes were characterized by a greater variation of the bending strength. In this case, beams with a strength of 24 MPa to 50 MPa appeared.

СОВЕРШЕНСТВОВАНИЕ ГИДРОМЕЛИОРАТИВНЫХ МАШИНС АВТОМАТИЗАЦИЕЙ ПРОЦЕССА ПОЛИВА

Целью исследования являлось теоретическое обоснование и практическая реализация нового способа полива гидромелиоративной машиной Фрегат с гидроприводом на сложном рельефе с минимальными затратами на модернизацию и энергозатратами. Объектом исследования является экспериментальный кранзадатчик скорости, устанавливаемый на гидромелиоративную машину. Исследования проводились в сравнении с показателями машин серийного производства. В ходе исследования было установлено, что существующая технология полива не отвечает необходимым требованиям гидромелиорации и имеет низкую степень экономической эффективности. Предлагаемая технология полива решает вопрос неравномерного распределения влаги по площади, повышает урожайность и снижает стоимость обслуживания машины вследствие уменьшения числа поломок. Имеющиеся модернизации дождевальной машины (ДМ) Фрегат , позволяющие работать по предлагаемой технологии, сложны по конструкции, ненадежны и имеют относительно высокую стоимость модернизации и сезонного обслуживания. С целью увеличения экономии средств и упрощения процесса модернизации серийных машин был разработан и протестирован кранзадатчик скорости, позволяющий снизить риск эрозии почв, застревания колес тележек и, тем самым, простой машины с необходимостью ее ремонта. Главной особенностью экспериментального краназадатчика скорости является его горизонтальное расположение относительно тележки. Два плеча с увеличенной длиной позволяют задавать поливную норму путем касания вех в начале каждого сектора, где необходимо сменить скорость движения машины. Таким образом, происходит регулирование поливной нормы, выдаваемой машиной при ее движении по орошаемой площади. Получившийся экономический эффект позволяет утверждать о положительных результатах в проведенных исследованияхThe aim of the research is the theoretical justification and practical implementation of the new method of irrigation irrigation and drainage machines Frigat with hydraulic drive for complex tasks of modernization and energy consumption. The object of the study is an experimental speedadjusting crane installed on a water reclamation machine. The studies were conducted in comparison with indicators of machine production. In the course of research it was found that the existing technology does not meet the requirements of irrigation and drainage and has a low degree of economic efficiency. The issue of uneven distribution of the owner by area, high productivity and low cost of maintenance is being addressed. DM Frigat, which allows you to work on the proposed technologies, does not require the cost of modernization and seasonal maintenance. In order to increase cost savings and develop new models of machines, a speed control crane has been developed and tested to reduce the risk of machine destruction. The operation of the trolley is the horizontal arrangement of the trolley. The speed of the machine can be increased. Thus, regulation of the irrigation rate occurs. The resulting economic effect allows us to argue about the positive results in the studies