Water Jet Vacuum Dust Suppression Device Used to Tunnel Development

2012 ◽  
Vol 594-597 ◽  
pp. 1188-1192
Author(s):  
Liu Jian ◽  
He Na ◽  
Yin Wen Wu ◽  
Liu Jin
Keyword(s):  
Negative Pressure ◽  
Mineral Water ◽  
Production Efficiency ◽  
Pressure Control ◽  
Test Methods ◽  
Water Jet ◽  
Working Environment ◽  
Control Measures ◽  
Dust Suppression ◽  
Main Factors

At present domestic tunnel construction, dust is one of the main factors which impact the production efficiency, safety clean production. It not only pollutes the environment, but also threats the health of workers. This article start from the tunnel dust prevention, control measures, heading face negative pressure control dust, and spray jet with the dust, to do research about the mineral water jet dust negative pressure technology. Combining experiments and field test methods, Study the dust fall mechanism of the tunnel water jet vacuum dust suppression, the device parameters and the effect of dust, the application of the technology has great significance to reduce the dust concentration of tunneling face and improve the working environment of workers.

Speed regulation control of tractors’ new dual-flow transmission system based on slip rate resistance classification

2021 ◽  
pp. 095440702110105
Author(s):  
Guang Xia ◽  
Yan Xia ◽  
Xiwen Tang ◽  
Linfeng Zhao ◽  
Baoqun Sun
Keyword(s):  
Control Strategy ◽  
Control Algorithm ◽  
Production Efficiency ◽  
Sliding Mode ◽  
Slip Rate ◽  
Speed Control ◽  
Working Environment ◽  
Vehicle Speed ◽  
Speed Change ◽  
Simulation Results

Fluctuations in operation resistance during the operating process lead to reduced efficiency in tractor production. To address this problem, the project team independently developed and designed a new type of hydraulic mechanical continuously variable transmission (HMCVT). Based on introducing the mechanical structure and transmission principle of the HMCVT system, the priority of slip rate control and vehicle speed control is determined by classifying the slip rate. In the process of vehicle speed control, the driving mode of HMCVT system suitable for the current resistance state is determined by classifying the operation resistance. The speed change rule under HMT and HST modes is formulated with the goal of the highest production efficiency, and the displacement ratio adjustment surfaces under HMT and HST modes are determined. A sliding mode control algorithm based on feedforward compensation is proposed to address the problem that the oil pressure fluctuation has influences on the adjustment accuracy of hydraulic pump displacement. The simulation results of Simulink show that this algorithm can not only accurately follow the expected signal changes, but has better tracking stability than traditional PID control algorithm. The HMCVT system and speed control strategy models were built, and simulation results show that the speed control strategy can restrict the slip rate of driving wheels within the allowable range when load or road conditions change. When the tractor speed is lower than the lower limit of the high-efficiency speed range, the speed change law formulated in this paper can improve the tractor speed faster than the traditional rule, and effectively ensure the production efficiency. The research results are of great significance for improving tractor’s adaptability to complex and changeable working environment and promoting agricultural production efficiency.

scholarly journals Dust Concentration Changing Regularities and Dust Reduction Technology by Spray Negative Pressure in Fully Mechanized Mining Face

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Lirong Wu ◽  
Hongxuan Chen ◽  
Jiamin Li ◽  
Shican Fu ◽  
Yuyan Zhuang
Keyword(s):  
Negative Pressure ◽  
Flow Characteristics ◽  
Dust Concentration ◽  
Inlet Section ◽  
Coal Face ◽  
Dust Suppression ◽  
Mining Face ◽  
Dust Distribution ◽  
Dust Reduction ◽  
Ventilation Velocity

The dust concentration changing regularities are the basis to take dust depression measures, which is greatly influenced by the airflow. In the software of FLUENT, the value of ventilation velocity is set as a constant, which cannot express the real ventilation. According to the flow characteristics of the sublayer and data from Nicholas’ experiment, the ventilation velocity distribution formula of sublayer in the inlet section of fully mechanized caving coal face is deduced. The boundary condition of velocity is given by UDF. Taking the 3top1110 fully mechanized caving coal face as an example, the dust distribution in the process of coal mining and hydraulic support shifting was studied. According to the dust-spray coupling experiment, three types of nozzle are chosen based on the efficiency of dust suppression. Combining the dust migration rule and the characteristics of nozzles, the negative pressure-secondary dust suppression devices of spray were developed and applied. And the above measures have lowered the dust concentration effectively.

Research on Negative Pressure Control Technology in NPP Reactor Building and its Application

2013 ◽  
Author(s):  
Jianghong Xie
Keyword(s):  
Power Unit ◽  
Negative Pressure ◽  
Nuclear Power ◽  
Pressure Control ◽  
Control Technology ◽  
Annular Space ◽  
Pressure System ◽  
Nuclear Power Unit ◽  
Reactor Building ◽  
Double Wall

The paper mainly elaborates the negative pressure control technology and commissioning approaches for double-wall containment of Russian WWER-1000 nuclear power units. It also carries out an analysis and research on the layered negative pressure technology in the containment. It mainly includes the following three parts: A Russian WWER-1000 nuclear power unit adopts the structure of double-wall containment for its Reactor building, with independent negative pressure systems for the containment and the annular space between the two walls. The paper mainly elaborates the control methods and limits requirements for the negative pressure in the containment and the annular space under the normal operation condition and in case of design basis accidents, with analysis and argumentation on the design function and operation requirements of the negative pressure system for the containment and the annular space. In the paper, the design philosophy of layered negative pressure and its feasibility study are analyzed from the aspects of radiated partition, air distribution of the negative pressure system and containment separator for layered negative pressure. The commissioning methods and technical requirements of negative pressure system in the Reactor building are described in the paper. Problems encountered during commissioning are also addressed and analyzed. Operations practices prove that the negative pressure control technology for double-wall containment of WWER-1000 nuclear power unit is advanced and reliable, which meets the requirements on nuclear air decontamination emission and radiation protection, and is worthy of study, research and reference.

Insufficient respiratory hazard identification in the safety data sheets for cleaning and disinfection products used in healthcare organisations across England and Wales

2021 ◽  
Vol 78 (4) ◽  
pp. 293-295
Author(s):  
Sewon Lee ◽  
Andrew C Povey ◽  
Martin J Seed ◽  
Martie van Tongeren
Keyword(s):  
Healthcare Workers ◽  
Safety Data ◽  
Qsar Model ◽  
Quantitative Structure Activity Relationship ◽  
Test Methods ◽  
Hazard Identification ◽  
Control Measures ◽  
Hazardous Chemicals ◽  
England And Wales ◽  
Cleaning And Disinfection

BackgroundExposure to cleaning and disinfection products has been associated with respiratory disorders such as asthma in cleaning and healthcare workers. Safety data sheets (SDSs) provide information on hazardous chemicals that are present in products to help users with risk assessment and implement appropriate control measures. However, they have potential limitations in identifying respiratory hazards due to a lack of regulatory test methods for respiratory sensitisation and irritation of chemicals.MethodsSDSs were first used to identify chemicals on the database as respiratory sensitisers and irritants. A quantitative structure–activity relationship (QSAR) model and an asthmagen list established by the Association of Occupational and Environmental Clinics (AOEC) were used to identify potential respiratory sensitisers and irritants (by the AOEC list only) in the cleaning and disinfection products.ResultsFrom a total of 459 cleaning and disinfection products used in healthcare organisations across England and Wales, 35 respiratory sensitisers not labelled as such on the SDS were identified by QSAR or AOEC. Only 2% of cleaning and disinfection products contained at least one respiratory sensitiser as identified by their SDSs; this was increased to 37.7% of products when the QSAR or the AOEC list was used.ConclusionsA significantly higher proportion of cleaning products contain respiratory hazardous chemicals, particularly respiratory sensitisers than would be expected from the information provided by SDSs alone. Cleaners and healthcare workers may, therefore, be insufficiently protected.

Effect of increases in lung volume on clearance of aerosolized solute from human lungs

1985 ◽  
Vol 59 (4) ◽  
pp. 1242-1248 ◽  
Author(s):  
J. D. Marks ◽  
J. M. Luce ◽  
N. M. Lazar ◽  
J. N. Wu ◽  
A. Lipavsky ◽  
...  
Keyword(s):  
Lung Volume ◽  
Negative Pressure ◽  
Ambient Pressure ◽  
Pressure Control ◽  
Positive Pressure ◽  
Healthy Humans ◽  
Human Lungs ◽  
Solute Uptake ◽  
Residual Capacity ◽  
Negative Pressure Breathing

To study the effect of increases in lung volume on solute uptake, we measured clearance of 99mTc-diethylenetriaminepentaacetic acid (Tc-DTPA) at different lung volumes in 19 healthy humans. Seven subjects inhaled aerosol (1 micron activity median aerodynamic diam) at ambient pressure; clearance and functional residual capacity (FRC) were measured at ambient pressure (control) and at increased lung volume produced by positive pressure [12 cmH2O continuous positive airway pressure (CPAP)] or negative pressure (voluntary breathing). Six different subjects inhaled aerosol at ambient pressure; clearance and FRC were measured at ambient pressure and CPAP of 6, 12, and 18 cmH2O pressure. Six additional subjects inhaled aerosol at ambient pressure or at CPAP of 12 cmH2O; clearance and FRC were determined at CPAP of 12 cmH2O. According to the results, Tc-DTPA clearance from human lungs is accelerated exponentially by increases in lung volume, this effect occurs whether lung volume is increased by positive or negative pressure breathing, and the effect is the same whether lung volume is increased during or after aerosol administration. The effect of lung volume must be recognized when interpreting the results of this method.

Control and Optimization of Negative Pressure in Scrap Copper Smelting

2011 ◽  
Vol 103 ◽  
pp. 399-403
Author(s):  
Ying Dao Li ◽  
Wei Hong Zhong ◽  
Hong Wei Guan ◽  
Xiu Shui Ma
Keyword(s):  
Pid Control ◽  
Negative Pressure ◽  
Control Method ◽  
Control Variable ◽  
Pressure Control ◽  
Copper Smelting ◽  
Smelting Process ◽  
Adjustment Process ◽  
Optimization Control

Negative pressure is the main control variable in scrap copper smelting process, the control of negative pressure is not only closely related with producing safely, but also produces a direct impact on the quality of the anode plate, it is also a key breakthrough in energy saving. This paper first analyses the characteristics of negative pressure control in scrap copper smelting process, aims to larger overshoot and longer regulation under conventional PID control method, and then utilizes fuzzy control to correct the PID parameters online, to achieve the optimization control of negative pressure. Simulation result shows that the adjustment process of optimized control of negative pressure is steady and rapid, usually no or slightly overshoot, and the settling time is also reduced significantly.

Nurses' Fears and Professional Obligations Concerning Possible Human-to-Human Avian Flu

2006 ◽  
Vol 13 (5) ◽  
pp. 455-470 ◽  
Author(s):  
Huey-Ming Tzeng ◽  
Chang-Yi Yin
Keyword(s):  
Nursing Students ◽  
Private University ◽  
Working Environment ◽  
Control Measures ◽  
H5n1 Influenza Virus ◽  
Avian Flu ◽  
Professional Obligations ◽  
Infection Control Measures ◽  
H5n1 Influenza ◽  
Southern Taiwan

This survey aimed to illustrate factors that contribute to nurses' fear when faced with a possible human-to-human avian flu pandemic and their willingness to care for patients with avian flu in Taiwan. The participants were nursing students with a lesser nursing credential who were currently enrolled in a bachelor degree program in a private university in southern Taiwan. Nearly 42% of the nurses did not think that, if there were an outbreak of avian flu, their working hospitals would have sufficient infection control measures and equipment to prevent nosocomial infection in their working environment. About 57% of the nurse participants indicated that they were willing to care for patients infected with avian influenza. Nurses' fear about an unknown infectious disease, such as the H5N1 influenza virus, could easily be heightened to levels above those occurring during the 2003 severe acute respiratory syndrome outbreak in Taiwan.

Study on Two-Step Aging Technology of 6082 Aluminum Bumper

2018 ◽  
Vol 764 ◽  
pp. 245-251
Author(s):  
Bei Ming Zhao ◽  
Miao Hu ◽  
Jun Zhu ◽  
Zhen Yu Han ◽  
Hou Qing Sun ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Process Parameters ◽  
Aging Temperature ◽  
Aging Process ◽  
Production Efficiency ◽  
Holding Time ◽  
Second Stage ◽  
Main Factors ◽  
6082 Aluminum Alloy

The influence of four parameters of two-step aging on the mechanical properties of 6082 aluminum alloy bumper was studied by orthogonal test. The results show that compared with the single stage aging, the two-step aging process can reduce the aging time and improve the production efficiency under the premise of the mechanical properties of the bumper meet the requirements. Among the four aging process parameters, the second stage aging temperature and holding time are the main factors that affect the final results, while the first stage aging temperature and holding time are secondary factors. The most suitable aging process parameters for the 6082 aluminum alloy bumper is (150 °C, 2 h) + (190 °C, 2.5 h). After two-step aging, the grain of the aluminum bumper is small and evenly distributed, leading to good mechanical properties. The generalized experiment shows that the application of the two-step aging process still has some limitations and needs to be further optimized and perfected.

Landslide Formation Mechanism and its Control Measures in Dabaolang

2014 ◽  
Vol 722 ◽  
pp. 419-422
Author(s):  
Peng Lv ◽  
Bao Yu Li ◽  
Yu Zhang ◽  
Yun Xun Zhang
Keyword(s):  
Prevention And Control ◽  
Evolutionary Process ◽  
Heavy Rain ◽  
Control Measures ◽  
Skid Resistance ◽  
Effective Prevention ◽  
Main Factors ◽  
Mechanism Of Landslide ◽  
The Stability ◽  
And Control

Through analyzing Dabaoliang geological characteristics, this paper discussed the factors of the mechanism of landslide in Dabaoliang area and simulated its evolutionary process. The paper could get some conclusions, and the factors of landslide are as follow: the stability of the slope which mainly composed by clastic rock not only depended on the performance of the mudstone layer but also the skid resistance of the sliding surface and the shape of slope. Under the influence of regional structure, the joint fissures which developed along the boundary of the landslide will connect the crack and benefit the permeation of the surface water. The heavy rain is one of the main factors caused the slope unstable and sliding. Provide effective prevention and control for prevention and control of projects.

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