IDENTIFICATION OF THE INFLUENCE OF THE SPATIAL ORIENTATION OF THE DEPOSITED LAYERS, AS WELL AS THEIR OVERLAP COEFFICIENT ON THE SURFACE SHAPE ERROR DURING ADDITIVE SHAPING BY AN ELECTRIC ARC

Статья посвящена изучению вопросов управления процессом аддитивного формообразования изделий. Представлены результаты исследования процесса аддитивного формообразования поверхности электрической дугой в среде защитного газа. Проведен анализ погрешности формы поверхностей, полученных с различным заполнением слоев. Подтверждено экспериментально, что такие параметры процесса, как ориентация слоев, коэффициент их перекрытия являются значимыми. Так, погрешность формообразования образцов наплавки слой на слой в вертикальном направлении выше по сравнению с другими способами наплавки, реализованными в эксперименте. Средние значения погрешности формы образцов составляют 0,75 мм, 0,88 мм, 1,15 мм, соответственно, для способов наплавки слой к слою на горизонтальную поверхность с коэффициентом перекрытия 0,3, слой к слою на горизонтальную поверхность с коэффициентом перекрытия 0,5, слой на слой в вертикальном направлении. Максимальные значения погрешности определены на уровне 0,85 мм, 1,2 мм, 1,5 мм для соответствующих способов наплавки, реализованных в эксперименте. Таким образом, пространственная ориентация слоев, а также коэффициент перекрытия слоев являются значимыми, оказывают влияние на численное значение погрешности формы получаемой поверхности, должны быть учтены при проектировании алгоритмов разделения на слои, их заполнения при аддитивном формообразовании электрической дугой в среде защитного газа The article is devoted to the study of the issues of managing the process of additive shaping of products. The paper presents the results of a study of the process of additive surface shaping by an electric arc in a protective gas medium. We analyzed the error of the shape of the surfaces obtained with different filling layers. We confirmed experimentally that such process parameters as the orientation of the layers, their overlap coefficient are significant. Thus, the error of forming samples of surfacing layer on layer in the vertical direction is higher compared to other methods of surfacing implemented in the experiment. The average values of the sample shape error are 0.75 mm, 0.88 mm, 1.15 mm, respectively, for methods of surfacing layer to layer on a horizontal surface with an overlap coefficient of 0.3, layer to layer on a horizontal surface with an overlap coefficient of 0.5, layer to layer in the vertical direction. The maximum error values are determined at the level of 0.85 mm, 1.2 mm, 1.5 mm for the corresponding surfacing methods implemented in the experiment. Thus, the spatial orientation of the layers, as well as the overlap coefficient of the layers, are significant, affect the numerical value of the shape error of the resulting surface, should be taken into account when designing algorithms for dividing into layers, filling them with additive shaping by an electric arc in a protective gas medium

Coefficient of mutual overlap in metal-polymer tribosystems

The polymer hybrid material under study is used as an antifriction coating of the friction contact surface. The experimental studies have been carried out on a special test bed with a reciprocating motion of the tribosystem in conditions of a mutual overlap coefficient less than one. The influence of the most important operational parameters, such as temperature, operating wear and wear rate, has been studied. The temperature was determined in the area of fixing the coating on a metal substrate, since the adhesive strength of the coating ensures the operability of this tribosystem. In addition, for the maximum friction modes, such standard parameters as the wear intensity and service life have been calculated. The wear resistance class has been set.

INFLUENCE OF THE OVERLAP COEFFICIENT ON THE CONTRAST IN LASER MARKING OF C110W STEEL

The laser marking process by melting samples of C110W carbon tool steel was studied. The experiments were performed with a fiber laser and a CuBr laser. A field of squares is marked in a raster method for different values of the overlap coefficient and power density. The contrast of the marking is determined on each marked square. From the obtained experimental data, graphs of the dependence of the contrast on the overlap coefficient for three power densities were drawn. The obtained results for the two lasers are compared and the influence of the wavelength is indirectly analysed. The working intervals of the overlap coefficient for the studied power densities for the two lasers at which the optimal contrast in the processing zone is obtained are determined.

MATHEMATICAL MODEL OF A MODIFIED ROTMAN LENS BASED ON AN ASYMMETRIC STRIPE LINE

Печатные линзы Ротмана из-за своей достаточной простоты построения и за свои широкополосные свойства, а именно за счет коэффициента частотного перекрытия (может достигать 2-3 и даже более), являются одним из основных перспективных направлений для формирования лучей в многолучевых антенных решетках (МАР). Принцип работы таких линз основан на различных путях распространения волны внутри ее структуры, благодаря которому линза может работать в сверхширокой полосе частот. Но из-за этого возникает новая проблема, а именно: увеличение габаритных размеров антенной системы. Вследствие чего такую конструкцию очень сложно интегрировать в компактную систему приемопередатчика. Эту проблему предлагается решить путем разработки более компактной линзы Ротмана, сложенной пополам. Такой кардинальный метод изменения (уменьшения) габаритных размеров линзы Ротмана мы объясняем тем, что основным типом волны, переносящим подавляющую долю энергии, является волна ТЕМ, для которой практически отсутствует дисперсия в СВЧ-ламинатах с малыми потерями. А для радиолокации, радиопеленгации и связи нужны именно такие способы решения технических трудностей. Но перед тем как создать опытную модель или макет антенной решетки, необходимо провести ряд экспериментов, расчетов и подтвердить заданные технические характеристики ФАР. В данной работе была создана и посчитана математическая модель линзы Ротмана, основанная на том, что ее свернули пополам Rotman printed lenses are one of the main promising directions for ray formation in multipath antenna arrays (MAA) due to their sufficient simplicity of construction and their wide-band properties, namely, due to the frequency overlap coefficient (it can reach 2-3 or even more). The principle of operation of such lenses is based on different paths of wave propagation within its structure, thanks to which the lens can work with an extremely wide frequency band. However, because of this, a new problem arises - an increase in the overall dimensions of the antenna system. As a result, this design is very difficult to integrate into a compact transceiver system. This problem is proposed to be solved by developing a more compact Rotman lens folded in half. We explain this cardinal method of changing (reducing) the overall dimensions of the Rotman lens by the fact that the main type of wave that transfers the overwhelming share of energy is the TEM wave, for which there is practically no dispersion in microwave laminates with small losses. And for radar, radio direction finding and communication, these are the ways to solve technical difficulties. Before creating an experimental model or layout of the antenna array, it is necessary to conduct a number of experiments, calculations and confirm the specified technical characteristics of the PAA. In this paper, a mathematical model of the Rotman lens was created and calculated based on the fact that it was folded in half

Technological parameters of gas-dynamic spraying affecting the formation coating based on mixture of particles copper, zinc and corundum

The results of a study of the effect of the spraying temperature and the overlap coefficient on the formation of the coating structure based on a mixture of Cu, Zn and Al2O3 particles applied by cold gas-dynamic spraying are presented. X-ray diffraction analysis has shown a decrease in the size of coherent scattering regions (CSR) from 200 nm to 90 nm for copper and to 64 nm for zinc when using an overlap coefficient of 55 % and more significant (up to 22 nm) with an overlap of 64 %. The CSR sizes of electronic type compounds CuZn3 (ε-phase) and Cu5 Zn8 (γ-phase) are quite close to the CSR size of zinc. The microdeformation of copper decreases from 187 to 119 % with an increase in the deposition temperature and does not depend on the overlap coefficient. For the electronic compound of the ε-phase, the microstrain value increases, and the γ-phase decreases by 2 times (from 0.31 to 0.17 %). The mass fraction of aluminum oxide (corundum) decreases from 5.4 to 2.2 % with an increase in the spraying temperature. The use of the maximum spraying temperature of 450 °C is accompanied by the formation of zinc oxide, the mass fraction of which is 4.3 % with 64 % overlap.

Oscillation of gear mechanisms of construction machines

The article is devoted to the study of the influence of gearing errors on the vibration activity of the open gear transmission of construction machines. A brief review of the literature on the relevance of the topic of gear dynamics in different industries and the results achieved so far is given. The features of open gears of turning mechanisms of construction machines are highlighted: a large gear ratio, a large gearing module, the absence of a common frame for the gear and wheel, poor transmission lubrication conditions, a small degree of precision in the manufacture of gears and the actual overlap coefficient is close to one. With these features, the main internal source of vibration is the difference between the main steps of the gear and the wheel and the error of the involute profile of the teeth. The results of the study of the influence of these features of vibration damping and open gear transmission on the dynamics of the turning mechanism of the construction machine are presented. The studies were carried out on a generalized two-mass nonlinear dynamic model with internal perturbation from the gear pair and with structural damping. The studies were conducted mainly for the transitional modes of resonance. Based on the analysis of the results obtained and presented in the article, recommendations are given to reduce the fluctuations of the turning mechanisms of construction machines.

Analisis dan Perancangan Software Pengukur Kemiripan Desain Database Relasional

Pengukuran kemiripan entity relational diagram (ERD) dilakukan untuk mendapatkan nilai kemiripan secara semantik dan struktural pada dua ERD yang dibandingkan. Kemiripan struktural didapatkan dengan mendapatkan elemen-elemen yang ada pada ERD. kemiripan semantik dilakukan dengan membandingkan setiap kata pada data definition language (DDL) dari ERD. Untuk mengetahui nilai kesamaan tersebut pengecekan dilakukan dengan secara manual. Hal seperti ini membutuhkan waktu yang cukup lama. Selain itu, terjadinya human error juga sangat mungkin terjadi. Dalam penelitian ini penulis akan menganalisa dan merancang sebuah sistem yang dapat mengukur kemiripan ERD. Ada banyak metode yang digunakan untuk menganalisa kemiripan desain basis data relasional. Untuk kemiripan struktural menggunakan metode jaccard similarity, cosine coefficient, dice’s coefficient dan overlap coefficient. dan untuk kemiripan semantic digunakan levensthein. Hasil kemiripan ERD berupa nilai dari hasil perhitungan menggunakan metode jaccard similarity, cosine coefficient, dice’s coefficient, serta overlap coefficient untuk kemiripan struktural dan metode levensthein untuk kemiripan semantik

Activity patterns of jaguar and puma and their main prey in the Greater Madidi-Tambopata Landscape (Bolivia, Peru)

Activity pattern studies can help explain the coexistence of competing species. Between 2001 and 2017 we evaluated the activity pattern overlap of jaguar (Panthera onca), puma (Puma concolor), and their main prey, using camera traps at 17 Amazonian sites in the Greater Madidi-Tambopata Landscape. We used the Kernel density estimation to generate species activity patterns and the overlap between both cats. We then calculated the overlap coefficient (Δ) by carrying out 10,000 bootstraps (95%). Both cats were active 24 h a day. The puma has higher nocturnal activity (57%), whilst jaguar activity is split almost equally between night (53%) and day (47%). We did not find temporal segregation between jaguars and pumas, which showed similar activity patterns with a high overlapping coefficient (Δ4 = 0.84; 0.78–0.91). Also, we did not find significant differences between Male and Female activity patterns for both species (X2 = 0.50, gl = 1, P = 0.47). Moreover, both cats had significant overlap with the activity patterns of their main prey. Temporal segregation was not detected in any of our study sites within the Greater Madidi-Tambopata Landscape, suggesting that in this region, these predators employ other mechanisms to avoid competition.