Retrofitting Sprinkler Systems for Suppressing Dust Generated by Moving Vehicles Inside Farms

Fugitive dust is one of the well known problems in agriculture and it affects both humans and machine producing quality. Dust problems can seriously cause harmful diseases to workers and ruin expensive equipments. In this study, a dust formation generated in open environment by vehicles was analyzed on unpaved roads. Formed dust was measured by calculating total forces on the PM10 （airborne particles smaller than 10 mm） of dust particles, such as air velocity, gravity forces and air turbulence generated by the moving vehicle. The water fogger nozzle discharge was measured to determine the approximate droplets quantity in the air. The foggers were used to suppress the generated dust in an open environment via installing a proposed automatic suppression system which opens automatically when vehicles pass under the system. The relationship between water droplet speed and ability of collecting fugitive dust showed that high air temperature above 40oC and wind speed above 10 m s-1 have negative effects on the system’s ability of collecting dust due to evaporation of small radius droplets and/or drifting water droplets away from the effective area. The overall system efficiency was found to be 85% and the proposed dust suppression system was found to be a satisfying solution for reducing fugitive dust hazards.

Experimental study of suppressing the unbalanced response vibration of rotor system with a G-type integral squeeze film damper

Conventional squeeze film dampers have numerous challenges including lock up,bistable response and incoordinate precession.In order to resolve these nonlinear problems,a novel G-type integral squeeze film damper(GISFD)is proposed in this research.The experimental test rig is provided to investigate the rotor system with an unbalanced single disk.Numerical simulation results show that the structural design of GISFD is reasonable,which can ensure its safe and stable operation.The influence of different support stiffnesses on the first-order speed of the rotor system is analyzed.Experimental results show that GISFD can effectively suppress the unbalanced response vibration of the rotor.In a certain range,it is found that the suppression effect of GISFD increases with the increase in the kinematic viscosity of the damping fluid.When the silicone oil with kinematic viscosity coefficients v=30.0 cm^(2)/s is employed,the vibration reduction of GISFD is approximately 71.51%.Furthermore,the experimental results show that with the increase of the unbalance,there is a linear relationship between the unbalance and the corresponding amplitude of the unbalanced response.It is concluded that GISFD has excellent linear damping characteristics and reduces the sensitivity of the rotor system to the unbalanced mass.

Suppression and synchronization of chaos in uncertain time-delay physical system

The mechanical horizontal platform(MHP)system exhibits a rich chaotic behavior.The chaotic MHP system has applications in the earthquake and offshore industries.This article proposes a robust adaptive continuous control(RACC)algorithm.It investigates the control and synchronization of chaos in the uncertain MHP system with time-delay in the presence of unknown state-dependent and time-dependent disturbances.The closed-loop system contains most of the nonlinear terms that enhance the complexity of the dynamical system;it improves the efficiency of the closed-loop.The proposed RACC approach(a)accomplishes faster convergence of the perturbed state variables(synchronization errors)to the desired steady-state,(b)eradicates the effect of unknown state-dependent and time-dependent disturbances,and(c)suppresses undesirable chattering in the feedback control inputs.This paper describes a detailed closed-loop stability analysis based on the Lyapunov-Krasovskii functional theory and Lyapunov stability technique.It provides parameter adaptation laws that confirm the convergence of the uncertain parameters to some constant values.The computer simulation results endorse the theoretical findings and provide a comparative performance.

Discussion on Dust Removal(Suppression)System of Crushing Station in Open-Pit Coal Mine

This paper introduces the method of coal dust treatment in crushing station and the present situation of dust removal system in typical open-pit coal mine crushing station in China,and expounds the research idea of determining comprehensive dust removal(suppression)system in crushing station inspired by the working principle of"range hood".Based on the design example and link optimization of the crush-ing station of open-pit coal mine I of Thar coalfield,this paper finally draws some conclusions on the key technologies of dust removal(suppression)system of open-pit coal mine crushing station.This study has certain reference value for the technical innovation of dust removal(suppression)system in crushing station,the realization of green mining in"crushing link",and the reduction and avoidance of ecological environment pollution in mining area.

A review of fire-extinguishing agent on suppressing lithium-ion batteries fire

Safety issue of lithium-ion batteries(LIBs)such as fires and explosions is a significant challenge for their large scale applications.Considering the continuously increased battery energy density and wider large-scale battery pack applications,the possibility of LIBs fire significantly increases.Because of the fast burning and the easy re-ignition characteristics of LIBs,achieving an efficient and prompt LIBs fire suppression is critical for minimizing the fire hazards.Different from conventional fire hazards,the LIBs fire shows complicated and comprehensive characteristics,and an effective and suitable fire-extinguishing agent particularly designed for LIBs is highly desirable.Considerable efforts have been devoted to this topic,to the best of our knowledge,a comprehensive review on this regard is still rare.Moreover,in practice,a guidance for the design and selections of a proper fire-extinguishing agent for LIBs is urgently needed.Herein,the special mechanisms and characteristics for LIBs fire and the corresponding design principles for LIBs fire-extinguishing agent were introduced.It is revealed that a fire-extinguishing agent developed for LIBs fire will most likely need a high heat capacity,high wetting,low viscosity and low electrical conductivity.After a comprehensive comparison of these agents in terms of these performances,water-based fire-extinguishing agents show best.Several typical fire-extinguishing agents such as gaseous agents,dry powders,water-based and aerosol fire-extinguishing agents were then introduced,and their fire extinguishment mechanisms were presented.Finally,their effectiveness in suppressing the fire were summarized.Water-based fire-extinguishing agents possess high cooling capacity and excellent anti-reflash performance for the fire.We believe this review could shed light on developing an efficient fire-extinguishing agent particularly designed for LIBs.

Review of Infrared signature suppression systems using optical blocking method

With rapid advancements in Infra-Red (IR) detection techniques, the range from where the IR-guided missiles are able to lock the target aircraft has increased. To avoid the detection and tracking by modern IR-guided missiles, the aircraft and helicopters also demand progress in its stealth techniques. Hence, study of Infra-Red Signature Suppression (IRSS) systems in aircraft and helicopters has become vital even in design stage. Optical blocking (masking) is one of the effective IRSS techniques used to block the Line- Of-Sight (LOS) of the hot engine parts of the exhaust geometry. This paper reviews the various patents on IR signature suppression systems based on the optical blocking method or a combination of IRSS techniques. The performance penalties generated due to installation of various IRSS methods in aircraft and helicopters are also discussed.

Recent research advances of self-discharge in supercapacitors:Mechanisms and suppressing strategies

Supercapacitors are one of the most promising energy storage devices in the fields of vehicle transportation,flexible electronic devices,aerospace,etc.However,the existed self-discharge that is the spontaneous voltage decay after supercapacitors are fully charged,brings about the wide gap between experimental studies and practical utilization of supercapacitors.Although eliminating the selfdischarge completely is not reachable,suppressing the self-discharge rate to the lowest point is possible and feasible.So far,the significant endeavors have been devoted to achieve this goal.Herein,we summary and discuss the possible mechanisms for the self-discharge and the underlying influence factors.Moreover,the strategies to suppress the self-discharge are systemically summed up by three independent but unified aspects:modifying the electrode,modulating the electrolyte and tuning the separator.Finally,the major challenges to suppress the self-discharge of supercapacitors are concluded and the promising strategies are also pointed out and discussed.This review is presented with the view of serving as a guideline to suppress the self-discharge of supercapacitors and to across-the-board facilitate their widespread application.

The efficiency and toxicity of dodecafluoro-2-methylpentan-3-one in suppressing lithium-ion battery fire

Currently,the effective and clean suppression of lithium-ion battery(LIB)fires remains a challenge.The present work investigates the use of various inhibitor doses(Xin)of dodecafluoro-2-methylpentan-3-one(C_(6) F_(12)O)in 300 Ah LIBs,and systematically examines the thermal and toxic hazards of the extinguished batteries via real scale combustion and gas analysis.The inhibitor is shown to be completely effective.The inhibition mechanism involves a combination of chemical inhibition and physical cooling.While the chemical inhibition effect tends to saturate with increasing Xin,the physical cooling remains effective at higher inhibitor doses.However,extinguishing the battery fire with a high Xin of C_(6)F_(12)O is found to incur serious toxicity problems.These results are expected to provide a guideline for the design of inhibitor doses for the suppression of LIB fires.

New Respirable Dust Suppression Systems for Coal Mines

Dust suppression in coal mines is a worldwide problem which has not been solved effectively. The applica-tion of negative pressure secondary dust removal (NPSDR) is a breakthrough in the coal mine safety field. In this paper,NPSDR technology and ultrasonic dust suppression systems are introduced. High pressure water is supplied to the NPSDR device which is mounted on the shearer. A negative pressure field is formed in the device. At the same time,the dusty air around the shearer drum will be sucked into,and purged from,the NPSDR device by the negative pressure field. An ultrasonic dust suppression system uses water and compressed air to produce micron sized droplets which suppress respirable coal dust effectively. The NPSDR technology can be used for shearer dust suppression while ultra-sonic dust suppression can be applied in areas such as the transportation positions. These dust suppression methods have the following advantages: high efficiency,wide applicability,simple structure,high reliability and low cost.

Suppressing Charge Recombination in ZnO-Nanorod-Based Perovskite Solar Cells with Atomic-Layer-Deposition TiO2

ZnO nanorods are passivated with a TiO2 interracial layer and applied in the CH3NH3PbI3 perovskite solar cell, which prepared by the atomic layer deposition method show a positive effect on the tiff factor and power conversion efficiency. With TiO2 interracial passivation, the charge recombination in the ZnO/CH3NH3PbI3 interface is effectively suppressed and the maximum power conversion efficiency is enhanced from 11.9% to 13.4%.

Simultaneously Suppressing Low-Frequency and Relaxation Oscillation Intensity Noise in a DBR Single-Frequency Phosphate Fiber Laser

Effective multiple optoelectronic feedback circuits for simultaneously suppressing low-frequency and relaxation oscillation intensity noise in a single-frequency phosphate fiber laser are demonstrated. The forward transfer function, which relates the laser output intensity to the pump modulations, is measured and analyzed. A custom two-path feedback system operating at different frequency bands is designed to adjust the pump current directly. The relative intensity noise is decreased by 20dB from 0.2 to 5kHz and over lOdB from 5 to lOkHz. The relaxation oscillation peak is suppressed by 22dB. In addition, a long term （24h） laser instability of less than 0.05% is achieved.

Narrow-band interference excision in spread-spectrum systems using new N-sigma algorithm based on fuzzy threshold

The key to narrow-band interference excision in frequency domain is to determine the excision thresh- old in direct-sequence spread-spectrum （DS-SS） systems. The excision threshold is a non-linear function related to the number and the power of interference, and attempting to get the exact relation of threshold related to the number and the power of interference is almost impossible. The N-sigma algorithm determines the excision threshold using subsection function; however, the excision threshold determined by this method is not exact. A new method to determine the threshold of N-sigma algorithm is proposed. The new method modifies the scale factor N by use of the membership function. The threshold determined by this method is consecutive and smooth, and it is closer to the fact than that of the initial N-sigma algorithm. The GPS signal and single-tone （CW） interference （that is, typical narrow-band interference） are implemented in the simulation, and the results are presented to demonstrate the validity of the new algorithm.

System Design and Signal Processing for Frequency Diverse Array Radar

Frequency diverse array(FDA)radar has been studied for more than 15 years and has attracted a lot of attention due to its potential advantages over the well-known phased array radar.The representative feature of FDA is range-angle-time-dependent transmit beampattern and its underlying properties are continuously revealed in the research.The formulation and exploitation of the transmit diversity with a frequency increment is the fundamental principle,which brings extra degrees-of-freedom(DOFs)in the transmit dimension.As the FDA radar carries additional information in range,it provides more flexibility in signal processing and also brings in new technical issues.This article overviews the state-of-the-art in FDA radar area and its applications,mainly based on the progress in our group.There are two main catalogs in FDA radar area,namely coherent FDA and FDA-MIMO(multiple-input multiple-output)radars.Potential applications including target parameter estimation,ambiguous clutter suppression,and deceptive jammer suppression are discussed.

MECHANICAL-ELECTRIC COUPLING DYNAMICAL CHARACTERISTICS OF AN ULTRA-HIGH SPEED GRINDING MOTORIZED SPINDLE SYSTEM

On the basis of the traditional mechanical model of a grinding wheel rotor and the mechanical-electric coupling model with ideal sinusoidal supply, taking high-frequency converting current of inverter power switches into further consideration, a modified mechanical-electric coupling model is created. The created model consists of an inverter, a motorized spindle, a grinding wheel and grinding loads. Some typical non-stationary processes of the grinding system with two different supplies, including the starting, the speed rising and the break in grinding loads, are compared by making use of the created model. One supply is an ideal sinusoidal voltage source, the other is an inverter. The theoretical analysis of the high-order harmonic is also compared with the experimental result. The material strategy of suppressing high-order harmonic mechanical-electric coupling vibration by optimizing inverter operating parameters is proposed.

Evidence of X-mode heating suppressing O-mode heating

In this study,we present three experiments carried out at the EISCAT(European Incoherent Scatter Scientific Association)heating facility on October 29 and 30,2015.The results from the first experiment showed overshoot during the O-mode heating period.The second experiment,which used cold-start X-mode heating,showed the generation of parametric decay instability,whereas overshoot was not observed.The third experiment used power-stepped X-mode heating with noticeable O-mode wave leakage.Parametric decay instability and oscillating two-stream instability were generated at the O-mode reflection height without the overshoot effect,which implies suppression of the thermal parametric instability with X-mode heating.We propose that the electron temperature increased because X-mode heating below the upper hybrid height decreased the growth rate of the thermal parametric instability.

Independent Component Analysis Based Blind Adaptive Interference Reduction and Symbol Recovery for OFDM Systems

To overcome the inter-carrier interference （ICI） of orthogonal frequency division multiplexing （OFDM） systems subject to unknown carrier frequency offset （CFO） and multipath, this paper develops a blind adaptive interference suppression scheme based on independent component analysis （ICA）. Taking into account statistical independence of subcarriers＇ signals of OFDM, the signal recovery mechanism is investigated to achieve the goal of blind equalization. The received OFDM signals can be considered as the mixed observation signals. The effect of CFO and multipath corresponds to the mixing matrix in the problem of blind source separation （BSS） framework. In this paper, the ICA- based OFDM system model is built, and the proposed ICA-based detector is exploited to extract source signals from the observation of a received mixture based on the assumption of statistical independence between the sources. The blind separation technique can increase spectral efficiency and provide robustness performance against erroneous parameter estimation problem. Theoretical analysis and simulation results show that compared with the conventional pilot-based scheme, the improved performance of OFDM systems is obtained by the proposed ICA-based detection technique.

Numerical simulations of sloshing and suppressing sloshing using the optimization technology method

Sloshing is a common phenomenon in nature and industry, and it is important in many fields, such as marine engineering and aerospace engineering. To reduce the sloshing load on the side walls, the topology optimization and optimal control methods are used to design the shape of the board, which is fixed in the middle of the tank. The results show that the new board shape, which is designed via topology optimization, can significantly reduce the sloshing load on the side wall.

Xanthium Suppression Under Maize||Sunflower Intercropping System

Weed control is one of the major constraint factors in crop production around the world. Field experiments were conducted during 2008-2009 under intercropping systems involving alfalfa （Medicago sativa L.）, sweet potato （lpomoea batatas [L.] Lain.）, peanut （Arachis hypogaea L.）, and sunflower （Helianthus annuus L.） in maize （Zea mays L.） without any weeds control methods taken. The results demonstrate that maizellsunflower is most effective on weed suppression and that it also has a more competitively inhibitory effect on Xanthium compared with the other patterns by evaluating the Xanthium density and dry weight under different intercropping systems with maize. Maizellpeanut, maizellalfalfa and maizel]sweet potato intercrops have no apparent inhibitory effect on weeds. To further investigate the effect of maize]lsunflower on weed control, indoor pot experiments were conducted by determining the effect of extractions on germination rate （GR）, root vigor, MDA （malondialdehyde）, SOD （superoxide dismutase） and POD （peroxidase） content of Xanthium. The results better prove that maizellsunflower extractions have more significant inhibitory effect on GR and young root vigor of Xanthium than maize monocrop extractions.

Model analysis and resonance suppression of wide-bandwidth inertial reference system

In the fields of earth observation,deep space detection,laser communication,and directional energyweapon,the target needs to be observed and pointed at accurately.Acquisition,tracking,and pointing(ATP)systems are usually designed to stabilize the line of sight(LOS)within sub-micro radian levels.In the case of an ATP system mounted on a mobile platform,angular disturbances experienced by the mobile platform will seriously affect the LOS.To overcome the problemthat the sampling frequency of detectors is usually limited and achieving several hundreds of hertz is difficult,thewide-bandwidth inertial reference system(WBIRS)and fast steeringmirror are usually integrated into ATP systems to mitigate these angular disturbances.To reduce the structural stress,a flexible support providing two rotational degrees of freedomis usually adopted for the system.However,the occurrence of resonant points within the bandwidthwill be inevitable.Measurements have to be taken to compensate these low-frequency resonant points to realize a wide bandwidth and high precision.In this paper,the lowfrequency resonant points of a systemwere simulated using finite element analysis and tested by a systemidentification method.The results show that the first-order resonance happened at 34.5 Hz with a gain of 28 dB.An improved double-T notch filter was designed and applied in a real-time system to suppress the resonance at 34.5 Hz.The experimental results show that the resonance was significantly suppressed.In particular,the resonance peak was reduced by 79.37%.In addition,the closed-loop system settling time was reduced by 36.2%.

Suppression of Chaotic Behaviors in a Complex Biological System by Disturbance Observer-based Derivative-Integral Terminal Sliding Mode

Coronary artery systems are a kind of complex biological systems. Their chaotic phenomena can lead to serious health problems and illness development. From the perspective of engineering, this paper investigates the chaos suppression problem. At first, nonlinear dynamics of coronary artery systems are presented. To suppress the chaotic phenomena, the method of derivative-integral terminal sliding mode control is adopted. Since coronary artery systems suffer from uncertainties, the technique of disturbance observer is taken into consideration. The stability of such a control system that integrates the derivative-integral terminal sliding mode controller and the disturbance observer is proven in the sense of Lyapunov. To verify the feasibility and effectiveness of the proposed strategy, simulation results are illustrated in comparison with a benchmark.