A simulation analysis of PV powered Inc-Cond MPPT based hybrid filter for power quality improvement

This paper proposed a Transformer less Hybrid Active Filter that upgrade the power quality in single-stage frameworks with steady renewable Photo Voltaic. It strengthens basic loads and carrying on as high-consonant impedance that does not below the critical loads. Manages energy management and power quality issues identified with electric transportation and concentrate on enhancing the electric vehicle load connected to grid. The control technique was intended to anticipation of current harmonic distortions with the nonlinear loads to control the flow of utility with no standard massive and expensive transformer. Power factor alongside AC side will likewise kept up to some esteem and furthermore dispense with the voltage distortions at the Common coupling point.

IMPROVING THE STABILITY OF THE MOVEMENT OF TRAILED VEHICLES

Today, automobile and tractor trains with trailers are quite popular vehicles used for transporting agricultural goods in the agro-industrial complex of the Russian Federation. Road trains and trac-tors with trailers are characterized by lower performance indicators (maneuverability, stability of movement) than single vehicles. Accordingly, special requirements for safety and trouble-free op-eration are imposed on motor-tractor trains. The author of the article proposes a technical solution that provides longitudinal stability of the movement of multi-link trackless vehicles, and has, in comparison with known analogues, simplicity of design and increased efficiency in the operating conditions of multi-link tractor trains. Analytical studies have been carried out, which made it possible to justify the rational kinematic and geometric parameters of the proposed technical solu-tion. The strength parameters of the damping device installed at the coupling point of tractors and trailers, and ensuring the operational reliability of trailed dump vehicles, are determined. The re-sults of the conducted research are recommended to both domestic and foreign research institutes, design and production structures of the automotive industry for further study and refinement of the proposed device with a view to its possible introduction into practice.

A Saturated-unsaturated Coupling Model for Groundwater Flowing into Seepage Wells: A Modeling Study for Groundwater Development in River Basins

As a major and popular groundwater extraction structure, seepage wells are often used to transfer river water into aquifers for harvesting water resources. It can help ameliorate the imbalance between supply and demand, especially in areas of water shortage. Large drawdowns due to pumping may cause the river to disconnect from the groundwater and to form an unsaturated zone, which seriously affects the efficiency of seepage wells. However, most of the current models of extraction structures of non-tube wells only account for saturated flow and do not consider unsaturated conditions. To address this limitation, a saturated-unsaturated coupling model has been developed using the exchange flow rate between the well pipe and the aquifer as the coupling point. Moreover, the model was evaluated with physical simulation test data. The statistical results indicated that the model can estimate the drawdown and pumping rate well with root-mean-square deviations (RMSD) of 0.0114 m and 0.0079 L/s, respectively, for a river with strong leakage capacity, and 0.0129 m and 0.0099 L/s, respectively, for a river with weak leakage capacity. The critical drawdown, where the river disconnects from the aquifer, as well as variations of the unsaturated zone, is also discussed. The present study provides important information for the design of seepage wells with reasonable drawdown while being able to predict the potential water yield, and at the same time help protect the groundwater environment.

Analysis of Fibre Cross-Coupling Mechanisms in Fibre-Optical Force Sensors

The force-enhanced light coupling between two optical fibres is investigated for the application in a pressure or force sensor, which can be arranged into arrays and integrated into textile surfaces. The optical coupling mechanisms such as the influence of the applied force, the losses at the coupling point and the angular alignment of the two fibres are studied experimentally and numerically. The results reveal that most of the losses occur at the deformation of the pump fibre. Only a small percentage of the cross-coupled light from the pump fibre is actually captured by the probe fibre. Thus, the coupling and therefore the sensor signal can be strongly increased by a proper crossing angle between the fibres, which lead to a coupling efficiency of 3%, a sensitivity improvement of more than 20 dB compared to the orthogonal alignment of the two fibres.

π-phase modulated monolayer supercritical lens

The emerging monolayer transition metal dichalcogenides have provided an unprecedented material platform for miniaturized opto-electronic devices with integrated functionalities. Although excitonic light–matter interactions associated with their direct bandgaps have received tremendous research efforts, wavefront engineering is less appreciated due to the suppressed phase accumulation effects resulting from the vanishingly small thicknesses. By introducing loss-assisted singular phase behaviour near the critical coupling point, we demonstrate that integration of monolayer MoS2 on a planar ZnO/Si substrate, approaching the physical thickness limit of the material, enables a π phase jump. Moreover, highly dispersive extinctions of MoS2 further empowers broadband phase regulation and enables binary phase-modulated supercritical lenses manifesting constant sub-diffraction-limited focal spots of 0.7 Airy units (AU) from the blue to yellow wavelength range. Our demonstrations downscaling optical elements to atomic thicknesses open new routes for ultra-compact opto-electronic systems harnessing two-dimensional semiconductor platforms with integrated functionalities.

Influence of multiple pre-injection on engine performance based on exhaust gas control

With the development of the society, the emission laws are increasingly strict, and EGR and multiple pre-injection strategy can effectively reduce emissions. In order to study the influence of EGR rate and pre-injection on the emission and performance of engine, a computational fluid dynamics (CFD) simulation model was established based on GT power. By changing the EGR rate, the number of pre-injection and the amount of pre-injection, the best technology coupling point is explored. The results show that EGR can effectively reduce the generation of NOx, but it will lead to the increase of soot production and the decrease of power; pre-injection can improve the trade-off relationship between NOx and power.