Conditions Of Different Velocities Research Articles

Enhancement of partial oxidation reformer by the free-section addition for hydrogen production

Hydrogen production by the partial oxidation combustion in porous media provides an efficient utilization for renewable biogas. In this paper, the free section with lengths of 0, 5, 10, 15 mm were designed in the middle of two-section porous media respectively. The effects of free section addition on the temperature distribution and methane conversion were investigated to determine the optimal burner parameters at the operating conditions of different velocities and equivalence ratios. Results indicate that the highest temperature appeared in the free length of 10 mm but the maximum of H2 energy conversion efficiency was in that of 15 mm. For the Al2O3 ceramic foam of 20 PPI, the better heat recirculation and preheating effect were shown between the gas and solid. However, the productions of H2 and CO at the 10 PPI burner reached the highest. With the increasing of equivalence ratio from 1.4 to 1.8, the energy conversion efficiency of syngas rose from 41% to 61% with the 15 mm free length. The appropriate free section addition contributes to improving the reforming efficiency, which provides a new way for the burner design.

Investigation on the Lift Force Induced by the Interceptor and Its Affecting Factors: Experimental Study with Captive Model

An interceptor is an appendage widely used for high-speed planing boats to reduce resistance and modify hull attitude by the lift force-induced, but the relationship between the induced lift force and the factors affecting it are still not clear, especially for the vessels other than the planing hull. In this paper, a model test of a series of models is performed to investigate the lift force induced by an interceptor and the influence of the affecting factors systematically. The lift forces induced by the interceptor are tested in the conditions of different velocities, interceptor heights, angles, and drafts in the towing tank. The effects of each factor and the coupled effects are analyzed. It is found by the experimental results that the lift coefficient of the induce lift force in the present investigation is approximately proportional to the square of the non-dimensional velocity and interceptor height, but the effect of the interceptor height is of a limited extent. The influence of angle and draft on the lift force induced by the interceptor cannot be ignored in the present study. The induced lift force is decreased when the angle of the plate is reduced and is enhanced when the draft is increased.

Four wheel independent drive electric vehicle lateral stability control strategy

In this paper, a kind of lateral stability control strategy is put forward about the four wheel independent drive electric vehicle. The design of control system adopts hierarchical structure. Unlike the previous control strategy, this paper introduces a method which is the combination of sliding mode control and optimal allocation algorithm. According to the driver&#x02BC s operation commands &#x0028 steering angle and speed &#x0029 , the steady state responses of the sideslip angle and yaw rate are obtained. Based on this, the reference model is built. Upper controller adopts the sliding mode control principle to obtain the desired yawing moment demand. Lower controller is designed to satisfy the desired yawing moment demand by optimal allocation of the tire longitudinal forces. Firstly, the optimization goal is built to minimize the actuator cost. Secondly, the weighted least-square method is used to design the tire longitudinal forces optimization distribution strategy under the constraint conditions of actuator and the friction oval. Beyond that, when the optimal allocation algorithm is not applied, a method of axial load ratio distribution is adopted. Finally, CarSim associated with Simulink simulation experiments are designed under the conditions of different velocities and different pavements. The simulation results show that the control strategy designed in this paper has a good following effect comparing with the reference model and the sideslip angle &#x03B2 is controlled within a small rang at the same time. Beyond that, based on the optimal distribution mode, the electromagnetic torque phase of each wheel can follow the trend of the vertical force of the tire, which shows the effectiveness of the optimal distribution algorithm.

Suppression of the Background with Drastic Brightness Jumps in a Sequence of Images of Dynamic Small-Size Objects

Among other problems, systems of space monitoring of the near-Earth space include detection of moving low-contrast objects in images with a powerful spatially nonstationary background significantly exceeding random (in most cases, weakly correlated) noise. The most effective method of increasing the signal-to-noise ratio under the conditions of different velocities of the objects and background is interframe processing of a sequence of images, which ensures suppression of the background component in the current frame by means of subtracting its estimate obtained from the previous frames. The problem is the presence of a priori unknown motion of the background, leading to significant errors in estimate formation in the regions of its sudden changes. The algorithm of interframe processing is studied, which allows one to estimate moderate local motions of the background and to compensate for them down to fractions of the sampling step. Results of full-scale modeling are presented, which demonstrate the possibility of background component suppression down to the noise level even in regions with its drastic changes.

Cooperative guidance with multiple constraints using convex optimization

In the existing closed-loop cooperative guidance approaches for salvo attack of multiple missiles, the multiple constraints and time-variant velocity basically cannot be effectively considered. Therefore, two closed-loop cooperative guidance methods are developed in this paper, by employing the efficient convex optimization technique and receding horizon control (RHC) strategy. During each guidance cycle of RHC, the system coordination target is updated and then broadcasted to each missile as a constraint. Subsequently, the convex optimization technique is utilized to solve the multi-constraint optimal proportional guidance problem of each missile online to achieve the consensus on time-to-go among missiles. Simulation results show that for three cases with different conditions of velocity, the cooperative simultaneous attack under multiple constraints can be effectively carried out using each of the two proposed cooperative guidance laws, which verify their effectiveness and feasibility.

Research on the motion characteristics of a trans-media vehicle when entering water obliquely at low speed

This paper proposes a single control strategy to solve the problem of trans-media vehicle difficult control. The proposed control strategy is just to control the vehicle's air navigation, but not to control the underwater navigation. The hydrodynamic model of a vehicle when entering water obliquely at low speed has been founded to analyze the motion characteristics. Two methods have been used to simulate the vehicle entering water in the same condition: numerical simulation method and theoretical model solving method. And the results of the two methods can validate the hydrodynamic model founded in this paper. The entering water motion in the conditions of different velocity, different angle, and different attack angle has been simulated by this hydrodynamic model and the simulation has been analyzed. And the change rule of the vehicle's gestures and position when entering water has been obtained by analysis. This entering water rule will guide the follow-up of a series of research, such as the underwater navigation, the exiting water process and so on.

Handover Optimization Algorithm in LTE High-Speed Railway Environment

The traditional A3 event-based HO algorithms are mainly designed for the low speed (<30 m/s) networks. That aren't suitable for the high-speed railway scenario which the link quality may deteriorate sharply and the wireless channel environment may become unstable with the increase of velocity. To overcome the disadvantages of the handover algorithms in LTE high-speed railway networks, we proposed a handover optimization algorithm based on statistics, where we not only consider reference signal received power and reference signal received quality at the same time but also the rate of cell resources change. The simulation results show that the proposed algorithm has higher handover success rate and lower handover numbers. Thus unnecessary handover is reduced by up to 47 % and the novel algorithm provides success rate of 0.5---13.9 % higher than the classical A3 algorithm under different conditions of velocity, and greatly improve handover performance.

Еstimation of intrusion detection probability by passive infrared detectors

Subject of Research. The paper deals with estimation of detection probability of intruder by passive infrared detector in different conditions of velocity and direction for automated analyses of physical protection systems effectiveness. Method. Analytic formulas for detection distance distribution laws obtained by means of experimental histogram approximation are used. Main Results. Applicability of different distribution laws has been studied, such as Rayleigh, Gauss, Gamma, Maxwell and Weibull distribution. Based on walk tests results, approximation of experimental histograms of detection distance probability distribution laws by passive infrared detectors was done. Conformity of the histograms to the mentioned analytical laws according to fitting criterion 2 has been checked for different conditions of velocity and direction of intruder movement. Mean and variance of approximate distribution laws were equal to the same parameters of experimental histograms for corresponding intruder movement parameters. Approximation accuracy evaluation for above mentioned laws was done with significance level of 0.05. According to fitting criterion 2, the Rayleigh and Gamma laws are corresponded mostly close to the histograms for different velocity and direction of intruder movement. Dependences of approximation accuracy for different conditions of intrusion have been got. They are usable for choosing an approximation law in the certain condition. Practical Relevance. Analytic formulas for detection probability are usable for modeling of intrusion process and objective effectiveness estimation of physical protection systems by both developers and users.

Cyclic strain rate in tyres as power source to augment automobile autonomy

The strain rate that takes place in the belts of tyres during automobile movement is proposed for converting mechanical energy into electricity. This paper describes how cyclic strain in tyres can be used for exciting piezoelectric materials placed in contact with the inner side of the tyre belt. Stress strain in tyre belts is caused by total mass weight in equilibrium with a pressurising condition. Under this condition, one section of the tyre in contact with the pavement deforms gradually until a maximum is reached, followed by a smooth release. The effect is continuous during each cycle of tyre rotation. Numerical simulations based on the finite element method were conducted for calculating the stress in composite materials that reproduce a combination of tyre belt–piezoelectric polymer films. Results were obtained for different conditions of velocity and automobile total mass. The piezoelectric material was sectioned into elements that cover the entire belt interior, leading to continuous generation of electricity. The numerical simulations assumed that automobile speed varied from 0 to 113 km/hr, combined with mass increments from one to five passengers, for a constant inflation pressure. The results indicate that electric current generated by the strain-stress in tyres increases almost linearly as a function of weight and speed. The electricity generated in tyres can be used to recharge the batteries in hybrid and conventional cars. It can even lead to reductions of alternator capacity. This process is a function of travel distance as well, since harvesting of energy takes place every tyre cycle.

Wear Rate Prediction and Analysis of Metal-Matrix of Ni-Based Super Alloy onto Cast Iron by Laser Cladding

Metal- matrix composites layers were prepared by laser cladding with Ni-based Super-alloy onto CrMo cast iron. Applying uniform experiment design, under conditions of different velocity and load ,the wear tests of alloy layers were carried out and the stepwise regression method are used to establish the wear rate model for prediction of wear rate. It is proved that the modal is significant and represents the character of the wear trend. According to the wear rate model ,the wear characteristics are analysed and the wear mechanisms are identified. The main wear mechanism of laser cladding layer are delamination, adhesive wear and abrasive wear.

Development of a padless ultraprecision polishing method using electrorheological fluid

A new kind of polishing method for mirror surface using the electrorheological (ER) fluid is presented. ER fluid is colloidal suspension and stiffens into semi-solid when subjected to an electric field. In this study, the mixture of the ER fluid and abrasives is used as polishing slurry. When the ER fluid is placed at the interface between a part and a moving platen, the friction force increases with the applied voltage. Since the polymeric ER particles separating two surfaces attract neighboring fine abrasives along the electric field across the gap, making the abrasives participate in material removal, they replace roles of pad used in a common mirror polishing. This paper analyzes the friction characteristics of the ER fluid at the sliding interface experimentally, and the behavior of the ER particles at the interface with and without the application of an electric field is observed optically. In addition, material removal rate of single crystal silicon according to the electric field strength is evaluated using the mixture of the ER fluid and diamond powders for a few conditions of different velocities and normal pressures. At last, average surface roughness of 2.9nm is obtained as a result of the polishing of silicon surface whose average roughness is about 50nm with the 0.25μm diamond-mixed ER fluid.

The comparison of basalt magmatism in the conditions of different velocity of spreading by the example of the Mid-Atlantic Ridge and the East Pacific Rise

The comparison of basalt magmatism in the conditions of different velocity of spreading by the example of the Mid-Atlantic Ridge and the East Pacific Rise