scholarly journals Study on Soil Throwing Performance and Ditch Depth Stability of Ditching Device in Sandy Orchards in Southern Xinjiang

2021 ◽  
Vol 11 (24) ◽  
pp. 12058
Author(s):  
Liangliang Li ◽  
Jie Chen ◽  
Chen Ma ◽  
Hewei Meng ◽  
Jiangtao Qi ◽  
...  
Keyword(s):  
Organic Fertilizer ◽  
Wheel Speed ◽  
Curved Surface ◽  
Operating Parameters ◽  
Soil Particles ◽  
The Stability ◽  
Soil Bin ◽  
Test Objects ◽  
Poor Stability ◽  
Southern Xinjiang

In order to solve the problems of serious soil reflux and poor stability of ditch depth in the existing ditching organic fertilizer fertilization device in grey desert and loess orchards, rotary tillage theory and software simulation were used to conduct kinematic analysis of soil particles and ditching blade in the ditching process, and meanwhile, modeling and simulation are carried out for sand soil particles by using EDEM software, so as to determine the action mechanism of soil, blade and fairing in ditching process of grey desert and loess. The abstract on this basis, the quadratic orthogonal regression-rotation combination experiment was designed. The soil bin test was carried out by taking the cutter wheel speed, ditching depth and inclination of curved surface as the influencing factors, and the throwing distance and the stability of ditch depth as the test indexes. And it was concluded that the order of the influence of the operating parameters of the ditching device on the soil throwing distance is ditching depth > inclination of curved surface > cutter speed, and the order of the influence on the stability of the ditch depth is ditching depth > cutter speed > Inclination of curved surface. Finally, the optimized operating parameters of the ditching device are as follows: the cutter wheel speed is 119.61 r·min−1, the inclination of curved surface is 30.07°, the ditching depth is 35.52 mm, the soil throwing distance is 57.31, and the stability of ditch depth is 87.43. With these parameters as test objects, 10 groups of single factor tests were carried out to obtain that the soil throwing distance is 58.33, and the stability of ditch depth is 86.51, which were basically consistent with the expected results of the optimization test, and also in line with the relevant agronomic standards.

Sensitivity Analysis and Numerical Stability Analysis of the Algorithms for Predicting the Performance of Turbines

2014 ◽  
Vol 136 (9) ◽  
Author(s):  
Ming Wei ◽  
Yonghong Wang ◽  
Huafen Song
Keyword(s):  
Numerical Stability ◽  
Rounding Error ◽  
One Dimensional ◽  
Flow Models ◽  
Numerical Stability Analysis ◽  
Last Stage ◽  
The Stability ◽  
Performance Calculation ◽  
Poor Stability ◽  
Input Error

Sensitivity and numerical stability of an algorithm are two of the most important criteria to evaluate its performance. For all published turbine flow models, except Wang method, can be named the “top-down” method (TDM) in which the performance of turbines is calculated from the first stage to the last stage row by row; only Wang method originally proposed by Yonghong Wang can be named the “bottom-up” method (BUM) in which the performance of turbines is calculated from the last stage to the first stage row by row. To find the reason why the stability of the two methods is of great difference, the Wang flow model is researched. The model readily applies to TDM and BUM. How the stability of the two algorithms affected by input error and rounding error is analyzed, the error propagation and distribution in the two methods are obtained. In order to explain the problem more intuitively, the stability of the two methods is described by geometrical ideas. To compare with the known data, the performance of a particular type of turbine is calculated through a series of procedures based on the two algorithms. The results are as follows. The more the calculating point approaches the critical point, the poorer the stability of TDM is. The poor stability can even cause failure in the calculation of TDM. However, BUM has not only good stability but also high accuracy. The result provides an accurate and reliable method (BUM) for estimating the performance of turbines, and it can apply to all one-dimensional performance calculation method for turbine.

Calculating the Electric Network Operating Parameters Taking into Account the Phase-Shifting Transformer's Variable Reactance

Vestnik MEI ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 11-20
Author(s):  
Sergey V. Loktionov ◽  
◽  
Aleksey V. Kochergin ◽  
Aleksey N. Sharov ◽  
Gleb S. Loktionov ◽  
...  
Keyword(s):  
Developed Countries ◽  
Electrical Circuit ◽  
Active Power ◽  
Phase Shifting ◽  
Electrical Network ◽  
Operating Parameters ◽  
Design Features ◽  
Active Power Losses ◽  
The Stability ◽  
Cis Countries

The aim of the work is to study the effect the variation of the phase-shifting transformer (PST) reactance has on the accuracy of calculating its control angle and the electrical network operating parameters obtained as a result of this control. The operating parameters, in particular, active power flows in the electrical circuit branches, are controlled by changing the PST angle; however, in view of the PST design features, this control entails a change of its reactance. Depending on the design features of different PST models and the control angle value, the PST reactance may be constant or vary in a significant range. In connection with a growing use of PSTs in industrially developed countries and with the fact that the first samples of this equipment have emerged in the CIS countries, including Russia, an increased attention is paid to this topic in a number of domestic and foreign publications. In particular, matters concerned with the stability of electric operation modes are considered in view of the fact that the PST reactance depends on its control angle, and the effect this dependence has on the operating parameters is estimated. The necessity of taking into account the varying PST reactance in calculating its control angle for controlling active power flows is considered for different cases. Forced redistribution of active power flows in the closed loops of an electrical network by means of a PST can be used to reduce active power losses and to maintain the required loading of the power lines for various reasons, for example, for commercial purposes or in the case of transit power flows between different countries. In view of the complexity of calculations, constant values of the PST reactance are usually assumed, but this approach is valid not for all types of PST designs. In the majority of PSTs, their reactance varies with increasing the control angle. Therefore, calculations carried out without taking this feature into account may yield a fortiori incorrect correspondence between the control angle and the transformer reactance value. In turn, an error will be introduced in the accuracy of the PST control angle calculations, as well as in the calculations of the operating parameters that should be obtained from the control action.

Effect of Some Anionic Starches on the Stability of Soil Particles in Water

1984 ◽  
Vol 36 (2) ◽  
pp. 56-60 ◽  
Author(s):  
M. O. Weaver ◽  
F. H. Otey ◽  
W. M. Doane
Keyword(s):  
Soil Particles ◽  
The Stability

A Buoyancy and Stability Mechanism for Underwater Vehicles

2000 ◽  
Vol 34 (2) ◽  
pp. 22-25
Author(s):  
Manikoth Aravindakshan
Keyword(s):  
Underwater Vehicles ◽  
Design Parameters ◽  
Vehicle Design ◽  
Hydraulic Power ◽  
Water Seepage ◽  
The Stability ◽  
Negative Buoyancy ◽  
Activation Depth ◽  
Poor Stability

This paper describes the design of a simple, inexpensive but effective ‘detach weight’ device that can aid in the stability as well as the recovery of underwater vehicles and unpropelled consoles. If the vehicle attempts to cross the maximum specified sea depth due to water seepage, poor stability, failure of normal recovery schedule, or inherent negative buoyancy as that of a console, then the proposed mechanism gets activated to achieve terminal buoyancy. Non-reliance on electrical, pneumatic or hydraulic power and sensors distinguish the device from conventional ballasting methods. Insitu assembly and adjustments of activation depth and weight can add flexibility to the vehicle design parameters such as overall CG, weight, trim, list etc.

Recent Progress in Black Phosphorus Sensors

2020 ◽  
Vol 16 (7) ◽  
pp. 1045-1064
Author(s):  
Tingting Ma ◽  
Hao Huang ◽  
Wenfei Guo ◽  
Chuanxiang Zhang ◽  
Zhu Chen ◽  
...  
Keyword(s):  
Carrier Mobility ◽  
Electrochemical Sensors ◽  
Black Phosphorus ◽  
Synthesis Methods ◽  
Tunable Bandgap ◽  
High Carrier Mobility ◽  
High Carrier ◽  
The Stability ◽  
New Sensors ◽  
Poor Stability

Black phosphorus (BP) is a new two-dimensional material with many unique properties, such as great biocompatibility, excellent surface activity, high carrier mobility, and tunable bandgap. Black phosphorus has been particularly attractive in sensor. However, black phosphorus isolated by traditional methods is easily oxidized and degraded by air, with poor stability, which limits its application as sensors. The modification and functionalization of black phosphorus enhance the stability, sensitivity, selectivity and biocompatibility of its application in sensor. This review describes recent progresses in sensor based on black phosphorus (2016–2020). Firstly, the structure and properties, synthesis methods, modification and functionalization of black phosphorus are briefly described. Then, the advancements in designing of various sensors based on black phosphorus are systematically provided, with a specific focus on electrochemical sensors, electrochemiluminescence sensors and photoelectrochemical sensors. Finally, latest challenges and further opportunities for developing new sensors with black phosphorus nanomaterial are discussed.

Analysis of the Stability of Current Mode PWM DC/DC Converter

2011 ◽  
Vol 143-144 ◽  
pp. 809-814
Author(s):  
Xiao Qiang Jia
Keyword(s):  
Duty Cycle ◽  
Current Mode ◽  
Compensation Circuit ◽  
The Poor ◽  
Slope Compensation ◽  
The Stability ◽  
Poor Stability

To address the poor Stability of current mode PWM DC / DC converter when duty cycle [5] is greater than 50%, by analyzing the converter, the design.of appropriate slope compensation circuit is given. And by Comparing the experimental waveform through simulation, it can effectively solve the converter poor stability and interference.of noise, if the slope compensation is appropriate.

Flight Dynamic Characteristic Analysis of a Generic Airbreathing Hypersonic Vehicle

2014 ◽  
Vol 716-717 ◽  
pp. 724-729 ◽  
Author(s):  
Rui Guang Yang ◽  
Jian Qiao Yu ◽  
Yuan Chuan Shen
Keyword(s):  
Dynamic Characteristic ◽  
High Speed ◽  
Complex Dynamics ◽  
Equations Of Motion ◽  
Hypersonic Vehicle ◽  
Propulsion System ◽  
Characteristic Analysis ◽  
The Stability ◽  
Dynamics Characteristic ◽  
Poor Stability

Because of the high speed, strong coupling between aerodynamics and propulsion system, complex environmental conditions and new propulsion system, the airbreathing hypersonic vehicles have a complex dynamics characteristic. This paper use the generic hypersonic vehicle model (CSULA-GHV) to research this issue. The nonlinear longitudinal equations of motion are linearized based on the assumption of little perturbation. Analyze the dynamic characteristic on a feature point selected. The results show that, the stability of this model is poor. It has to design an efficient controller to adjust the poor stability.

The Stability and Management of “Sandwich” Type Slopes in Extrusive Rock Area

2012 ◽  
Vol 472-475 ◽  
pp. 1253-1256
Author(s):  
Hong Wei ◽  
Hong Wang
Keyword(s):  
Hainan Island ◽  
Soil Layers ◽  
Loose Soil ◽  
Late Tertiary ◽  
Sandwich Type ◽  
Extrusive Rock ◽  
Management Method ◽  
The Stability ◽  
Faulted Zone ◽  
Poor Stability

Northern area of Hainan Island is located in the south of Leiqiong faulted zone; new tectonic movement and volcanic activity have intense since late tertiary. Cenozoic volcano in the region is developed, various types of extrusive rocks widely distributed which often directly cumulate on the Cenozoic sedimentary soil layers, then covered by more loose soil, form a soft - hard - soft “sandwich” type slope with a poor stability. Based on the study of this slope and simulate its stability, this paper proposed this kind of slope's destruction mechanism as well as the management method

scholarly journals Hilbert-Huang Transform Analysis of Machining Stability in Ball-Nose End-Milling of Curved Surface

2020 ◽  
Vol 14 (3) ◽  
pp. 500-511
Author(s):  
Muizuddin Azka ◽  
Keiji Yamada ◽  
Mahfudz Al Huda ◽  
Kyosuke Mani ◽  
Ryutaro Tanaka ◽  
...  
Keyword(s):  
Cutting Force ◽  
Inclination Angle ◽  
End Milling ◽  
Curved Surface ◽  
Hilbert Huang Transform ◽  
Time Frequency ◽  
Machining Errors ◽  
Cutting Velocity ◽  
Cylindrical Workpiece ◽  
The Stability

This paper investigates the machining stability in ball-end-milling of curved surface in which the inclination of tool continuously changes. Initially, the influence of inclination angle is geometrically investigated on the parameters such as immersion angle and cutting velocity. Then, the paper presents the stability lobe diagrams of the process. Curved surface milling is simulated by slot milling on a cylindrical workpiece using a ball-end-mill to obtain the cutting force and vibration, which are used for fast-Fourier transform and Hilbert-Huang transform (HHT) analyses. Experimental results show that the cutting force increases, and the stability becomes worse with the inclination angle, while the machining errors decrease with the inclination. The vibration analysis showed that the HHT can detect the transition from stable to unstable during milling of curved surface in the time-frequency plots.

scholarly journals Computational analysis on the stability and characteristics of partially premixed butane air open flames in tubular burner

2021 ◽  
pp. 320-320
Author(s):  
Zeenathul Abdul Gani ◽  
N. Muthu Saravanan
Keyword(s):  
Computational Study ◽  
Flame Temperature ◽  
Diffusion Mode ◽  
Partially Premixed Combustion ◽  
Stable Operating ◽  
Partially Premixed ◽  
Lift Off ◽  
The Stability ◽  
And Diffusion ◽  
Poor Stability

Partially premixed combustion is one of the developing areas of combustion research that has the advantages of both premixed and diffusion mode of combustion. The present work involves a computational study on the stability and characteristics of partially premixed butane-air flames. The effect of operating parameters like fuel-air ratio, primary aeration, and the presence of co-flow and co-swirl on the stability and flame characteristics has been studied. The simulation results show that the height of the flame decreases with an increase in primary aeration and also in the presence of a co-swirl stream. It has also been found that the stability of flames increases with co-swirl air but deteriorates with the presence of the co-flow air. The flame temperature increases with primary aeration and it has been observed that the peak flame temperature shifts away from the burner mouth for lower primary aeration. It has been observed that the flame stability improves with co-swirl air which is attributed to the recirculation zone created due to the swirl motion which acts as a heat source. The poor stability in the presence of co-flow air is attributed to flame stretching and aerodynamic quenching of the stretched flame lets. The lift off velocity and the stable operating range increases with equivalence ratio and also with co-swirl air.

Sign in / Sign up

Export Citation Format

Share Document