Modelling and optimization of energy intensity of an electrical discharge machine

Nowadays, high fabrication productivity and high-quality products are a matter of course. However, it would not be possible without the use of highly sophisticated progressive technologies in the production process. But many of these modern production technologies are characterized by high consumption of energy. Given the current energy prices, this is not an insignificant amount of money. It is also necessary to point out, that in many cases the rule concerning the mutual interconnection of the energy intensity of production technologies with the resulting quality of the machined area applies. These reasons led us to the optimization of energy consumption in the context of the required quality of the machined surface in terms of selected indicators. The paper aims to describe the results of the performed experimental measurements in order to create mathematical models with subsequent optimization of electricity consumption of an electrical discharge machine. Unlike many types of research conducted in the field so far, the results of the solution were based on determining the relationships between the energy intensity of the electrical discharge machine and its controllable outputs in terms of the final roughness of the eroded surface. The performed optimization based on experimentally obtained results was directed so that its results could be applied in real conditions of technical practice.

Rheological and Pipe Flow Properties of Chocolate Masses at Different Temperatures

Chocolate masses are one of the basic raw materials for the production of confectionery. Knowledge of their rheological and flow behaviour at different temperatures is absolutely necessary for the selection of a suitable technological process in their production and subsequent processing. In this article, the rheological properties (the effect of the shear strain rate on the shear stress or viscosity) of five different chocolate masses were determined—extra dark chocolate (EDC), dark chocolate (DC), milk chocolate (MC), white chocolate (WC), and ruby chocolate (RC). These chocolate masses showed thixotropic and plastic behaviour in the selected range of shear rates from 1 to 500 s−1 and at the specified temperatures of 36, 38, 40, 42, and 44 °C. The degree of thixotropic behaviour was evaluated by the size of the hysteresis area, and flow curves were constructed using the Bingham, Herschel–Bulkley and Casson models with respect to the plastic behaviour of the chocolate masses. According to the values of the coefficients of determination R2 and the sum of the squared estimate of errors (SSE), the models were chosen appropriately. The most suitable models are the Herschel–Bulkley and Casson models, which also model the shear thinning property of the liquids (pseudoplastic with a yield stress value). Using the coefficients of the rheological models and modified equations for the flow velocity of technical and biological fluids in standard piping, the 2D and 3D velocity profiles of the chocolate masses were further successfully modelled. The obtained values of coefficients and models can be used in conventional technical practice in the design of technological equipment structures and in current trends in the food industry, such as 3D food printing.

A New Payload Swing Angle Sensing Device and Its Accuracy

Measuring the swing angle of a crane load is a relatively well-known but unsatisfactorily solved problem in technical practice. This measurement is necessary for the automatic stabilization of load swing without human intervention. This article describes a technically simple and new approach to solving this problem. The focus of this work is to determine the accuracy of the measuring device. The focus of this work remains on the design, the principle of operation of the equipment, and the determination of accuracy. The basic idea is to apply the strain gauge on an elastic, easily deformable component that is part of the device. One part of the elastic component is fixedly connected to the frame; the other part is connected to the crane rope by means of pulleys close to the rope. In this way, the bending of the elastic component in proportion to the swing angle of the payload is ensured.

Overview of the modified magnetoelastic method applicability

<p class="Abstract">A requirement of axial force determination in important structural elements of a building or engineering structure during its construction or operational state is very frequent in technical practice. In civil engineering practice, five experimental techniques are usually used for evaluation of axial tensile forces in these elements. Each of them has its advantages and disadvantages. One of these methods is the magnetoelastic method, that can be used, for example, on engineering structures for experimental determination of the axial forces in prestressed structural elements made of ferromagnetic materials, e.g., prestressed bars, wires and strands. The article presents general principles of the magnetoelastic method, the magnetoelastic sensor layout and actual information and knowledge about practical application of the new approach based on the magnetoelastic principle on prestressed concrete structures. Subsequently, recent results of the experimental verification and the in-situ application of the method are described in the text. The described experimental approach is usable not only for newly built structures but in particular for existing ones. Furthermore, this approach is the only one effectively usable experimental method for determination of the prestressed force on existing prestressed concrete structures in many cases in the technical practice.</p>

Overview : International Guidelines on Natural and Nature-Based Features for Flood Risk Management

The application of natural and nature‑based features (NNBF) has grown steadily over the past 20 years, supported by calls for innovation in flood risk management (FRM) and nature‑based solutions from many different perspectives and organizations. Technical advancements in support of NNBF are increasingly the subject of peer‑reviewed and other technical literature. A variety of guidance has been published by numerous organizations to inform program‑level action and technical practice for specific types of nature‑based solutions. This effort to develop international guidelines on the use of NNBF was motivated by the need for a comprehensive guide that draws directly on the growing body of knowledge and experience from around the world to inform the process of conceptualizing, planning, designing, engineering, constructing, and operating NNBF.

Application of the ADINA Software for Tasks of Educational and Technical Practice

Development of the designing process in civil engineering brings the possibility for more complex analysis of the structures. Computational software can be helpful for regular design but also for identification and solving of more specified problems. Finite Element Method (FEM) became one of the most used numerical methods. Numerous commercial programs are based on this method. However, these programs are more complex and require skilled designer to fully utilize their potential. This article brings the lead to apply the FEM method implemented in commercial software ADINA to solve the problem of structural mechanics. It is necessary to connect the theoretical approach of FEM modeling and experience from real case problems. Skilled designer can calibrate the numerical model to obtain relevant outputs. However, certain cases still require a detailed and individual approach during designing that is verified by the in-situ monitoring and observation. Lead of the student to the flexible treatment of the design is one of the important tasks of the educational process. This involves the basic knowledge about appropriate analysis of the problem for effective utilization of the computational software for particular applications even for more complex solutions.

Towards Refusing as a Critical Technical Practice: Struggling With Hegemonic Computer Vision

Computer Vision (CV) algorithms are overwhelmingly presented as efficient, impartial, and desirable further developments of datafication and automation. In reality, hegemonic CV is a particular way of seeing that operates under the goal of identifying and naming, classifying and quantifying, and generally organizing the visual world to support surveillance, be it military or commercial. This paradigm of Computer Vision forms a ‘common sense’ that is difficult to break from, and thus requires radical forms of antagonism. The goal of this article is to sketch how refusing CV can be part of a counter-hegemonic practice – be it the refusal to work or other, more creative, responses. The article begins by defining hegemonic CV, the ‘common sense’ that frames machine seeing as neutral and impartial, while ignoring its wide application for surveillance. Then, it discusses the emergent notion of refusal, and why critical technical practice can be a useful framework for questioning hegemonic sociotechnical systems. Finally, several potential paths for refusing hegemonic CV are outlined by engaging with different layers of the systems’ 'stack.'