The shortcomings of existing waste-processing furnaces have been analyzed, and a new furnace design for electroslag remelting and combustion of waste, developed at Akaki Tsereteli State University, is proposed. It is demonstrated that its use enables the combustion and remelting of individual waste components without causing environmental pollution from combustion products.
Friction couplings for joining rebar are widely used in civil engineering and mechanical structures, including the construction of high-rise buildings, towers, bridges, overpasses, tunnels, dams, and other infrastructure. These friction couplings are mechanical elements that provide a strong and reliable connection between the components being joined by transferring loads through the friction force generated between the contact surfaces. This force is applied by the geometry of the friction coupling and the installation-induced clamping force. The primary factor governing the proper selection and application of a friction coupling is the cross-sectional diameter of the rebar, as the friction coupling must be designed to withstand the loads encountered under service conditions. In addition, environmental influences, particularly the difference in the coefficients of thermal expansion of the joined materials, represent an important consideration. Another critical factor is the installation process itself, as the performance of the friction coupling depends directly on proper installation. Therefore, comprehensive testing of the installed friction coupling is essential to ensure its reliable performance throughout its service life. This paper presents an original design solution for the development of a friction coupling for joining Ø25 mm rebar, developed through three successive design iterations. The proposed friction coupling is intended to ensure structural integrity under static and dynamic loading, including seismic loading and vibration. An initial prototype design was developed in accordance with the applicable technical standards and validated using the Finite Element Method (FEM) to evaluate its load-bearing capacity under static loading conditions and identify potential stress concentrations. The prototype models were manufactured using the Fused Filament Fabrication (FFF) additive manufacturing process with the support of CAD/CAE systems. The friction coupling was ergonomically designed through mass and shape optimization.
Today, renewable bioenergy is regarded as one of the ways to supply energy at the expense of fossil fuels. The possibility of obtaining energy from organic materials through bio-electrochemical systems has attracted considerable interest. Green waste consists of organic plant-based materials generated from grass clippings, broken branches, fallen trees, and others, whose utilization is currently not very effective. In this study, we constructed a depot based on bio-electrochemical systems for the utilization of green waste with cogeneration of energy. The facility demonstrated good performance in terms of both the degradation of organic matter and the energy produced.
This paper presents a study of some geometric characteristics of conic spatial rack drives with linear helicoids. Three variants of the conic configuration are considered — with convolute, involute, and Archimedean helicoids — and their action surface properties are analyzed in relation to the distribution parameter. The role of the distribution parameter in determining the geometry of the action surface and the position of each variant in the design parameter space is discussed.
Paper deals with a newly designed low-power three-phase induction electric motor for continuous duty cycle operation with application mainly in pumping system. The main features are presented. The problems and solutions related to the sizing and optimization of the motors during design according to different criteria and conditions are analyzed, with energy efficiency being the main determinant. Numerous graphical results obtained during the design are presented.
Parallel robot manipulators (or parallel manipulators) feature closed kinematic chains. Compared to serial manipulators, they possess high load-carrying capacity, high positioning accuracy, and good dynamic characteristics. Most parallel manipulators with six degrees of freedom (DOF) utilize six legs and are commonly referred to as hexapods. This article focuses on the study of three-legged parallel manipulators, known as tripods. In comparison with hexapods, tripods offer larger workspaces and fewer singular configurations. The paper examines 3-PRRS and 3-PRPS tripods as examples, where P, R, and S denote prismatic, revolute, and spherical joints, respectively. Their structural synthesis was performed, their geometry investigated, and the inverse kinematics problem was solved.
The vibration behavior of a healthy gear train is modelled as a sum of sinusoidal accelerations of a pinion, a gear, and a gear-mesh. A while noise is added trough waveform of normally distributed random numbers. The corresponding time-diagram and spectrogram are obtained. After that, an impulse acceleration waveform is added to simulate a teeth fault. The time-diagram and spectrogram are obtained again and compared. Conclusions are made.
The world’s maritime industry is currently undergoing an unprecedented transformation, driven by the climate crisis and the strict regulations imposed by the International Maritime Organization (IMO). The IMO’s Greenhouse Gas (GHG) Strategy for 2023 has fundamentally redefined the industry’s goals, from gradually reducing carbon intensity to comprehensively phasing out greenhouse gas emissions by 2050. At the heart of this transition is the low-speed, two-stroke engine, which serves as the main source of propulsion for most deep-sea merchant ships. Contrary to being considered a legacy of the limitations of the fossil fuel-dependent era, these engines are being transformed into highly efficient and adaptable platforms capable of using the next generation of carbon-neutral and zero-carbon energy carriers. This analysis examines the technical, operational and regulatory mechanisms that enable the maritime sector to meet its net-zero emission commitments, with a particular focus on dual-fuel engine architectures, advanced combustion control, and the holistic integration of ship energy systems.
Road experiments were conducted – when accelerating the motorcycle to the limit values of longitudinal geometric stability and the loss of contact of the front wheel with the road or reaching the “wheelie” phenomenon. From the theory of the motorcycle it follows that the critical accelerations depends on the height of the center of mass and its horizontal coordinate. In the presence of a passenger, the center of gravity is moved back and up, which leads to a decrease in the theoretical value of these accelerations. Therefore, the experiments were conducted on a motorcycle equipped with a suitcase and a passenger located on the back seat. The received information is recorded and visualized on a portable computer, and then processed in the Matlab and Excel environment. The results obtained from the experiments and the accumulation of databases can be used to create models for determining the influence of the driver’s behavior, the passenger’s influence, models for determining the behavior of the motorcycle and the comfort of the trip. During the measurements, the change in position of the driver and passenger is not taken into account.
A comparative analysis of wear performance of coated harrow discs by plasma-jet thermal deposition was evaluated under agricultural conditions to assess the performance of atmospheric plasma spraying systems. This paper presents a long-term comparative field evaluation under identical operating conditions on a quartz-rich argic luvisol soil. Disc wear was quantified by periodic measurements of mass loss and diameter of the studied discs.
The uncoated disc showed the most severe degradation, with a total mass loss of approximately 700 g and a rapid acceleration of wear after the first 5-10 ha of harrowing. The results obtained under field conditions demonstrate that the microstructural integrity of the coating is more critical than the nominal hardness and highlight the superior effectiveness of APS ceramic coatings for extending disc life in abrasive agricultural soils.
Cable-Stayed-Bridges are an important part of today’s constructions in the traffic infrastructure. New materials and computational technology have led to the construction of longer and slender Cable-Stayed-Bridges are under the effect of dynamic loads as wind, traffic or earthquakes. Besides comfort restrictions, the vibrations of large amplitudes effects also the lifetime of the entire structure. Oscillations of Cable-Stayed-Bridges can be reduced significantly by active damping systems. In this paper is represented shortly an electro-hydraulic actuator concept for the active damping of Cable-Stayed-Bridges. This type of control is very efficient even in large bridges (up to 900 m span). Also, the tests on a large-scale bridge show the efficiency of active damping in Cable-Stayed-Bridges using electro-hydraulic actuators. The damping of deck and cables, has become crucial in the design of cable-supported structures. Because of the effectiveness of passive damping systems is limited, this new electro-hydraulic actuator concept is developed.
In the context of a changing climate and the pursuit of sustainable development, any technology or device that produces green energy will help reduce dependence on fossil fuels. This work presents a prototype of an electro-generative pipeline element based on a bio-electrochemical system. The element is suitable for integration into pipelines carrying various liquids. The electro-generative element has shown high efficiency in laboratory conditions, and depending on the passing liquid, it can generate energy in the range of 0.5W – 1.5W. A different number of elements can be located in the pipeline system, depending on its length. Depending on the number of elements in the chain, enough energy can be obtained to power various devices.