An approach to the evaluation of mutual resistances of vibrators in the construction of a logoperiodic antenna of double polarization

В данной работе приведены результаты теоретического исследования взаимного влияния двух вибраторов, произвольно ориентированных в пространстве. Авторы на основе метода наведенных ЭДС определили касательную составляющую электрического поля, создаваемого одним из вибраторов в месте расположения второго. С использованием данного выражения авторы предложили три способа оценки взаимного сопротивления системы двух скрещенных симметричных вибраторов. Сравнив способы по точности вычислений и затрачиваемому машинному времени, авторы выделили один из предложенных способов для проведения модельных исследований. Особенностью предложенного способа является возможность обобщения расчетного выражения не только для случая скрещенных вибраторов, но и для случаев вибраторов, расположенных в параллельных плоскостях и перпендикулярных одной и той же прямой. Поскольку указанные случаи охватывают все возможные варианты взаимной ориентации вибраторов в конструкции логопериодической антенны двойной поляризации, то предложенный подход может быть использован при проведении модельных исследований направленных свойств логопериодической антенны и оценки уровня кросс-поляризации. The results of two arbitrarily oriented in space vibrators mutual influence theoretical study are presents in this paper. Based on the method of induced EMF, the authors determined the tangential component of the electric field created by one of the vibrators at the location of the second one. Using this expression, the authors proposed three ways to evaluate the mutual resistance of a system of two crossed symmetrical vibrators. Comparing the methods by the accuracy of calculations and the machine time spent, the authors identified one of the proposed methods for conducting model studies. A feature of the proposed method is the possibility of generalizing the calculated expression not only for the case of crossed vibrators, but also for the cases of vibrators located in parallel planes and perpendicular to the same straight line. Since these cases cover all possible variants of mutual orientation of vibrators in the construction of a logoperiodic antenna of double polarization, the proposed approach can be used in conducting model studies of directional properties of a logoperiodic antenna and assessing the level of cross-polarization.

Development of digital twin model of underground electric cable: thermal part of the problem

Innovative technologies of generative design using the concept of digital twins of the designed objects play an important role in growing digitalization trend of project activities. The digital twin of an object is the object simulation model with high accuracy of mathematical description. It is used to solve the problems of regime and structural optimization of the object. Usually, generative design technologies are implemented using 3D models of physical fields. And specialized packages which have high requirements for computer resources and user skills are used. At the same time, quite often the object for which the digital twin model is developed consists of several subsystems that allow relatively independent modeling. A one-dimensional model of the thermal process cannot provide the required accuracy, but a 2D-model is quite sufficient for this purpose. The development of such a model that combines the required accuracy, and low cost of machine time is currently topical scientific and practical problem. The method of mathematical modeling is used to solve this problem. The model uses the mathematical apparatus of the Markov chain theory. The model is two-dimensional and is adapted to the multi-layer environment representing the soil, in a separate cell of which a non-stationary heat source may be found. Heat passage through the surrounding soil is described in terms of thermal conductivity, and the heat exchange with the environment is described in terms of heat transfer. The influence of the parameters on the process flow is studied by numerical methods. At this stage of the study, experimental verification of the model is not expected. A mathematical two-dimensional model of digital twin of underground electric cable has been developed. It allows us to predict the cable temperature and its distribution in the surrounding soil. The assessment of thermal state of the power transmission line is given according to the power and the depth of the heat source location. It is found that the results of simulation modeling are consistent with the physical concepts of the process. The results obtained are of scientific novelty, since they are based on a universal modeling algorithm and allow us to describe the transients in the object under study, which is a part of the digital twin of the underground cable. The model is easy to use and requires little machine time. It can be easily used in generative design practice.

MODIFIKASI SISTEM KONTROL PROSES PRODUKSI PADA MESIN CBC GRAFIR DAN MESIN AUTOLOADER BERBASIS PLC CJ1M

Sebuah perusahaan yang memproduksi komponen kendaraan bermotor berupa piston. Proses produksi piston melalui dua tahapan proses yakni Foundry Process dan Machining Process. Perusahaan ini memiliki divisi-divisi yang berperan sebagai factory support, salah satunya yaitu Maintenance Division yang bertugas untuk melakukan perawatan mesin secara preventive maupun corective agar menjaga mesin tetap dalam kondisi baik untuk kegiatan proses produksi. Proses produksi piston melalui dua tahapan proses yakni Foundry Process dan Machining Process. Pada Machining proses di urutan kerja pembuatan piston terdapat mesin center bosk cutting (CBC) Grafir dan mesin Autoloader. Pada line 27 terdapat mesin CBC Grafir dan mesin Autoloader, mesin tersebut terpisah dan mempunyai sistem kontrol yang berbeda, penyemprotan manual setelah proses autoloader oleh operator, tidak adanya coolant untuk membersikan piston yang kotor akibat coolant dan penggantian program secara manual oleh tim maintenance ketika operator ingin mengganti model piston dan layout rak. Oleh karena itu penulis melakukan improvement berupa modifikasi sistem kontrol mesin CBC grafir dan Autoloader, di antaranya integrasi sistem kontrol mesin CBC grafir dan Autoloader yang sebelumnya menggunakan PLC yang berbeda, penambahan sistem penyemprotan angin otomatis dan pembersih berupa air hangat, dan penambahan switch untuk penggantian model piston dan layout rak piston. Pembuatan mesin ini meliputi pembuatan rangkaian elektrik dan program. Modifikasi tersebut mampu menurunkan machine time, mengurangi man power dan meningkatkan kualitas produk

ADAPTATION OF SOLID MODELS FOR SOLVING HEAT ENGINEERING PROBLEMS USING CAD CALCULATION MODULES

Показаны основные недостатки традиционных подходов к решению теплотехнических задач посредством аэродинамического моделирования при помощи ЭВМ для твердотельных моделей. Определены пути повышения эффективности и снижения трудоемкости проведения подобных расчетов благодаряметодике поэтапногоупрощения (адаптации) твердотельной геометрии. Произведена оценка экономии затрат системных ресурсов и машинного времени при использовании методики поэтапного упрощения твердотельной геометрии. Выявлена возможность расчета более сложных моделей при ограниченных аппаратных ресурсах за счет предложенного подхода. The main disadvantages of traditional approaches to solving thermal engineering problems by means of aerodynamic modeling using a computer for solid models are shown. The ways of increasing efficiency and reducing the labor intensity of such calculations due to the method of step-by-step simplification (adaptation) of solid geometry are determined. Cost savings of system resources and machine time were estimated using the technique of step-by-step simplification of a solid geometry. The possibility of calculating more complex models with limited hardware resources was revealed due to the proposed approach.

Manufacturing of the surfaces of spline fitting connection

The aim of this publication is the analysis of the geometric establishment and the manufacturing designing and development of spline fitting promoting the engineer’s designing works. There are many connection possibilities according to the utilization on different constructions. Based on them, different technologies are needed for the manufacturing of the spline shaft and the spline hole. Generally, milling and grinding technologies are needed. These technologies will be analysed. We design mathematical models for the analysis of the milling technologies by mathematical way. We define the technological parameters and the computed machine time for the manufacturing designing process and recommend technologies for the different shapes.

New results for an open time-dependent scheduling problem

We present several new results for a single machine time-dependent scheduling problem of minimizing the total completion time of a set of linearly deteriorating jobs with unit basic processing times. First, we show new properties of cyclic transformations of V-shaped sequences for this problem. Next, applying the results, we prove a new necessary condition of schedule optimality for the considered problem, which decreases the previous bound on the cardinality of the set containing all possible optimal schedules by a multiplicative factor which is at most proportional to the reciprocal of the square root of the number of jobs. Finally, we compare the strength of the new and the previous necessary conditions by estimation of the numbers of schedules satisfying the respective conditions.

Parameters Of Technological Processes Reengineering

The article is devoted to reengineering of technological processes - a method of their qualitative transformation on an innovative basis, which in turn assumes the availability of tools that make it possible to establish the economic efficiency and technical capability of such transformations of construction production, to identify the effect of their implementation. In this regard, the problem of forming a parametric model of reengineering of construction technological processes, which involves four enlarged groups of indicators that reflect the quantitative and qualitative characteristics of the processes: materials used, working time, machine time, spatial organization, is considered. It is established that parameters can have either an absolute (physical, cost) or relative (point, percentage) expression and also make their own decomposition. The practical significance of the provisions given in the article is determined by the development of methods of technical rationing, which leads to a reduction in the cost and duration of construction.

Modellerstellung für additive und spanende Verfahren/Model generation for additive and subtractive processes

Die additive Reparatur von beschädigten Bauteilen und Formen ist häufig mit hohen Kosten verbunden. Durch die digitale Vernetzung wurde ein Mehrwert in der additiven und spanenden Reparatur geschaffen, der sowohl die Anlagenzeit und Ingenieurszeit reduziert und gleichzeitig auf variable Genauigkeitsanforderungen übertragbar ist. Anhand einer Turbinenschaufel wurde der Reparaturprozess getestet und kann in der Zukunft auf beliebige Bauteile übertragen werden. The additive repair of damaged components and moulds is often associated with high costs, especially for SMEs. By digitally networking different components, an added value in additive and metal-cutting repair has been created, which reduces both machine time and engineering time and is at the same time transferable to variable accuracy requirements. The repair process was tested using a turbine blade and will be transferred to individual components in the future.