REMOVAL OF TECHNICAL AND ECONOMIC INDICATORS OF THE D-240 ENGINE WHEN USING BIOFUELS BY APPLYING THE DIESEL-RK SOFTWARE COMPLEX

Ukraine is one of the energy-deficient countries because it covers its needs in fuel and energy resources from domestic reserves by only 53% (imports 75% of the required natural gas and 85% of crude oil and petroleum products). Dependence on oil imports is seen by most developed countries as a matter of national and energy security, and the use of petroleum products as energy sources poses a significant environmental risk. According to the analysis of the state of the world engine industry, the most effective measures to improve the design of the engine are: development and implementation of a new workflow with effective methods of mixing and combustion; development and creation of the design of the system of automatic regulation of diesel rotation. frequency to improve fuel economy And to reduce toxicity in partial load mode, some cylinders are switched off at idle. To strengthen the requirements for fuel consumption standards and the level of toxicity of exhaust gases, as well as to increase the reliability and efficiency of agricultural power engines, it is necessary to formulate measures to improve its design. The choice of a fuel should be determined by the optimal combination of environmental and economic performance of the engine. Prospects for the use of a particular fuel of plant origin are noted. If for fuels of petroleum origin the improvement of its properties is determined by special processing, then oils with the set characteristics can be received already in "field" by selection of the corresponding grades of plants, use of fertilizers, agronomic actions, etc. The problem of reducing the consumption of diesel fuel at idle and low load can be solved by excluding from its operation part of the cylinders (this method is widely used) and closing the cycle of one cylinder. A comparative analysis of the main technical and environmental performance of the D-240 diesel engine when working on traditional and alternative fuels using the computer program Diesel-RK.

Bendductor—Transformer Steel Magnetomechanical Force Sensor

In this paper, the design and investigation of an innovative force sensor, based on the Villari effect, is presented. The sensor was built from electrical steel, in a pressductor pattern, but working in bending load mode. The results of the experimental research allowed for the evaluation of transducer’s performance, mitigation of measurement hysteresis, and optimization of its functional parameters. Several issues have been examined, among them the selection of supply and measured signals, the measured values’ impact on measurement hysteresis, harmonic analysis, and the selection of proper current waveforms and frequencies. The proposed sensor is robust, made from inexpensive materials, and has high sensitivity, as compared to other magnetoelastic sensors. It has much higher stress sensitivity than other magnetoelastic sensors due to deformation mode. Based on the tests, its measuring range can be defined as 0.5–5 N with a near-linear characteristic, SNR of 46 dB, and 0.11 N uncertainty.

THE INFLUENCE OF CATHODE MATERIAL ON THE CHARACTERISTICS OF PULSED NEGATIVE CORONA IN OXYGEN

Change in time for the shape of the discharge current pulses of the pulsed negative corona in oxygen with cop-per and stainless steel cathodes has been studied for two discharge modes. The change lies in the decrease of the pulse amplitude and duration at half maximum. It is shown that for stainless steel cathodes, the amount of electric charge transferred in one pulse of the discharge current is 15% greater than for copper cathodes. It is also shown that under the maximum load mode, the amount of charge transferred in one pulse of the discharge current is de-creased with time by 10% for both types of cathodes. It is shown that ozone synthesis in the electrode system with copper cathodes is 25% more efficient.

Global load determination in linear guides based on the fusion of local rolling element loads determined from strain sensitive sensor groups

Measuring the mechanical load on linear guides provides many possibilities regarding predictive maintenance and process monitoring. In this contribution, we provide an in depth evaluation of a Diamond Like Carbon (DLC) based sensor system integrated into the runner block’s raceway that is capable of directly measuring the load on individual rolling elements. An efficient algorithm based on an Extended Kalman Filter (EKF) for local sensor fusion and load estimation is presented and proven to reliably retrieve the load regardless of the rolling element’s position. Afterwards, we compare locally measured loads to results from a theoretical load distribution model, providing valuable insight into modeling parameters and a verification of the sensor measurement principle. In a final step, an algorithm to invert the load distribution model is derived and used for an evaluation of the sensor system, achieving Root-Mean-Square (RMS) estimation errors of equivalently 1.4 kN in the preload range and 2.75 kN overall for one dimensional loads. Load mode distinction was equally successful with a suppression RMS error of 0.7 kN in the preload range and 2.87 kN in total.

Fatigue in asphalt mixtures – a summary to understand the complexity of its mathematical modeling

Based on the reviewed literature in relation to the phenomenon of fatigue in asphalt mixtures, the foregoing paper depicts and describes in summary, the main variables that impact in the generation of said phenomenon in asphalt pavements. This has the purpose of showing its complexity to mathematically model it. As a general conclusion obtained in the study, it was found that the calibration difficulty of the models is mainly since the mathematical equations must be in capacity of considering that fatigue resistance of asphalt mixtures depends on load mode (stress-controlled or strain- controlled), the type of load (haversine or sinusoidal) and the rest periods to which laboratory samples are subjected. Additionally, both in situ, as within the laboratory, this varies with stiffness, volumetric composition (type and content of asphalt and aggregate), the geometry of samples, with effects associated to mix durability and environmental conditions, with the type of test, border conditions and support layers (base, subbase, subgrade). If these physical parameters are not considered, the mathematical equations lose reliability.

Simulation of the saturation process of a current transformer with a load

The article deals with the mathematical basis and simulation of the saturation processes of current transformers with aperiodic components of short-circuit currents. Saturation processes of current transformers can affect the correct operation of the protections. At power plants, in particular atomic ones, the number of current transformers is several hundred with different loads, lengths of supply cables and the implementation of relay protection. At the same time, the determination of the time to saturation is essential for the construction of circuits and principles of construction of relay protection systems and automation of power plants. The dynamic processes in the primary and secondary circuits of current transformers in dynamics are considered in detail. A mathematical description of the dynamic processes of a current transformer in the nominal mode and during a short circuit in its primary circuit is given. The substantiation of the expediency of using the hypothesis of a rectangular magnetization characteristic in simplified calculations of saturation processes is given. The possibility of using the characteristics of magnetization in the test protocols available in practice in the no-load mode to simulate saturation processes has been demonstrated. Simulation of current transformers for the no-load experiment and power supply of the current transformer from the secondary side, as well as during its operation under conditions of a short circuit on the primary side and a known load on the secondary side is carried out. Thus, with the help of a computer experiment, it is possible to take the current- voltage characteristics and transfer them to the model with the saturation of current transformers already in the short-circuit mode. The efficiency of dynamic simulation of current transformers is shown. The software implementation of the model is performed by means of structural simulation in the MatLab package, based on the solution of equations of matrix structures and emulation of parallel computations. It was found that with the adequacy of the model and the real current transformer with the involvement of information from the no-load mode, the determination of the magnetization time from the aperiodic current components from the model is much easier than the analysis by other existing methods. They require detailed design details of the current transformer and the magnetic properties of the steel.

Contacting Stability of Sliding Electrical Contacts

It is stated that the operation of the sliding contact unit is accompanied by vibrations of the brushes that occur as a result of internal and external mechanical influences. The resulting violations of the sliding contact (SC) and the instability of contacting lead to a deterioration in the quality of current transmission, increased sparking, accelerated wear of the SC. The article is devoted to the derivation and verification of universal formulas for calculating the relative instability factor (RIF) of the SC. Derived formulas allow calculating the RIF of any SC compounds. Mathematical expressions are obtained to determine the distributions of instability in the tangential and axial directions of the transition layer of the SC. An experimental stand for studying the instability of various SC compounds at idle and in the rated load mode is described. The contacting cycle, which establishes a correspondence between the instantaneous value of the length of the measuring platform and the movement of the collector is described. Expressions for determining the equivalent length of the measuring area for different cases of placing the measuring brush relative to the zone of the main sliding contact are derived. These formulas allow us to find the RIF of various SC regions on experimental data based.

An investigation on the degradation behaviors of Mg wires/PLA composite for bone fixation implants: influence of wire content and load mode

Poly-lactic acid based biocomposite strengthened with magnesium alloy wires (Mg wires/PLA composite) is prepared for bone fixation implantation. The influence of wire content and load mode on the degradation performances of the composite and its components is studied. The result suggests the degradation of Mg wires could slow down the pH decrease originated from the degradation of PLA, while a relatively high wire content contributes to descend the degradation rate of Mg wire in the composite. Dynamic load significantly promotes the mechanical loss of the specimens. After 30 days immersion, the Sb retention is about 65%, 52% and 55%, respectively for pure PLA, the composite at 10 vol% and 20 vol% under dynamic load, comparing to 75%, 70% and 72% under no load. Moreover, dynamic load could further mitigate the degradation of Mg wires by increasing convective transport of acidic products out of the composite.

Graph-analytical method of load mode analysis of ferromagnetic current stabilizer

In this paper we consider the application of graph-analytical method for the analysis of the load regime of ferromagnetic current stabilizer. It is proved that under active load the current of the ferromagnetic stabilizer and magnetic flux are related by the ellipse equation where the axes coincide with the axes of coordinate system. The advantage of the proposed method is that it is possible to use an experimentally obtained characteristic.