scholarly journals Determining the Height of Water-Flowing Fractured Zone in Bedrock-Soil Layer in a Jurassic Coalfield in Northern Shaanxi, China

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Jie Feng ◽  
Sujian Wang ◽  
Enke Hou ◽  
Xiang Ding ◽  
Huijun Duan
Keyword(s):  
Long Range ◽  
Apparent Density ◽  
Physical Simulation ◽  
Soil Layer ◽  
Imaging Technology ◽  
Fractured Zone ◽  
Northern Shaanxi ◽  
Layer Region ◽  
Scanning Imaging ◽  
And Control

The height of the water-flowing fractured zone is the most important technical parameter for water prevention and control in a coal mine. Due to the numerous factors affecting the water-flowing fractured zone, it is difficult to accurately identify the zone. Currently, no effective way exists for determination of the water-flowing fractured zone in a soil layer. To accurately determine the development law of the water-flowing fractured zone in the bedrock-soil layer of a Jurassic coalfield in northern Shaanxi, China, we conducted a comprehensive study using microresistivity scanning imaging technology, apparent density logging, long-range gamma logging, observation on drilling flushing fluid consumption, physical simulation, and numerical simulation. The following results were obtained: (1) The ratio of the height of the water-flowing fractured zone to the mining height was 28.3–28.5, which was obtained by microresistivity scanning imaging technology, whereas the ratio of the height of the water-flowing fractured zone to the mining height was 28.1–29.1, determined by apparent density logging, long-range gamma logging, physical simulation, and numerical simulation. The microresistivity scanning imaging results were consistent with those obtained by other methods. (2) Based on the thickness of the soil layer and the bedrock, the height model of the water-flowing fracture zone was divided into four regions, that is, the thick bedrock-thick soil layer region, thick bedrock-thin soil layer region, thin bedrock-thin soil layer region, and thin bedrock-thick soil layer region. A mathematical model describing the difference between the thickness of the water-flowing fractured zone and the bedrock and the thickness of the soil under the condition of bedrock-soil was established. (3) We conclude that microresistivity scanning imaging technology can accurately detect the height of the water-flowing fractured zone in a soil layer, and the apparent density logging and long-range gamma logging can precisely detect the height of the water-flowing fractured zone in bedrock. This is a new comprehensive method for research on the height of the water-flowing fractured zone that can provide a reliable basis for water prevention and control in mines.

scholarly journals Nanoparticles and Public Health

2011 ◽  
Vol 19 (3) ◽  
pp. 72-72
Author(s):  
Graham Cliff
Keyword(s):  
Public Health ◽  
Electron Microscope ◽  
Environmental Impact ◽  
Long Range ◽  
Graduate Student ◽  
Monitoring And Control ◽  
Small Particles ◽  
Analytical Electron ◽  
Analytical Electron Microscope ◽  
And Control

I write this as a materials scientist concerned about the inadequacy of regulation, monitoring, and control of what are known as nanoparticles (NPs). This is not because present particulate legislation is “inadequate” but because it is inadequately policed and does NOT extend to small enough particulates. I have analyzed these very small particles in the analytical electron microscope (AEM) for over thirty-seven years. A graduate student, with whom I worked over thirty years ago, described in her thesis the conclusion that these particles would have “long-range environmental impact.” We did not then have the benefit of hindsight.

scholarly journals ORGANIC PRODUCTION IS THE BASIS OF HEALTH OF PEOPLE AND NATURE

2018 ◽  
Vol 2018 (7) ◽  
pp. 76-83
Author(s):  
Bogdan KUZNYAK ◽  
Keyword(s):  
Organic Farming ◽  
Plant Protection ◽  
Soil Layer ◽  
Organic Production ◽  
Organic Fertilizers ◽  
Mineral Fertilizers ◽  
Natural Fertility ◽  
Difficult Situation ◽  
Strategic Direction ◽  
And Control

The search of forms and methods of promoting the development of organic agriculture, consumption of organic products and its distribution through the long-term marketing concept is considered. Life expectancy in Ukraine in recent years has decreased by 10 years compared to European countries. The natural fertility of the land is gradually deteriorating due to excessive use of mineral fertilizers, pesticides, toxic chemicals and other negative factors. This led to destruction of the fertile soil layer and its most valuable component – humus, the content of which has decreased from 13-14% to 3-5% over the past 100 years. This significantly worsened the living conditions of soil microorganisms ensuring the activities of organic substances and nutrition of agricultural plants and reduced the quality of grown produce, which adversely affects the health of people and nature. The way out of this difficult situation is the transition to organic farming, which at the present stage is increasingly becoming a global strategic direction. The basic principles of organic farming are: (i) refusal to use mineral fertilizers and chemical means of plant protection (pesticides); (ii) use of organic fertilizers and siderates (“green fertilizers”, which fill the soil with organic mass and destroy weeds); (iii) surface cultivation of the soil (not more than 11 cm) sufficient for fluffing its upper layer, protection against weeds and microform balance; (iv) provision of scientifically sound crop rotation, which ensures fertility of the soil and control of weeds and pathogens.

Underwater Optical Imaging Technology and its Applications

2013 ◽  
Vol 710 ◽  
pp. 408-412
Author(s):  
Rong Zeng ◽  
Jun Hua He ◽  
Pei Lv
Keyword(s):  
Compressive Sensing ◽  
Optical Imaging ◽  
Laser Scanning ◽  
Laser Imaging ◽  
Imaging Technology ◽  
Underwater Laser ◽  
Scanning Imaging

The applications of underwater optical imaging technology are reviewed. The main types of underwater laser imaging technology are introduced, such as underwater laser scanning imaging and underwater distance selected imaging. The respective imaging principle and characteristics are presented. Furthermore, the newest imaging technology, such as underwater compressive sensing imaging technology is described in detail. The recent researching status is included.

Range Prediction and Trajectory Correction of Long Range Rocket with Attitude Stabilization

2012 ◽  
Vol 232 ◽  
pp. 299-304
Author(s):  
Ke Yong Li ◽  
Fen Fen Xiong ◽  
Cheng Zhang ◽  
Shi Shi Chen
Keyword(s):  
Long Range ◽  
Prediction Method ◽  
Longitudinal Direction ◽  
Control Mode ◽  
Attitude Stabilization ◽  
Large Dispersion ◽  
Range Correction ◽  
And Control ◽  
Range Error ◽  
The Impact

The dispersion of long range rocket is significantly suppressed by the attitude stabilization in the boost phase. However, the attitude stabilization system cannot govern the propellant impulse error and mass error, which induces large dispersion in the longitudinal direction. Therefore, it is necessary to conduct range correction in the post-boost phase of flight trajectory. A range prediction method based on the elliptic ballistic theory is proposed in this paper. Elliptic ballistic equations and range estimation equations are derived and the modified range prediction method with correction factor is presented. It is verified that the proposed method can predict the residual flight range accurately. After that, the lateral pulse jets control is presented and utilized to correct the trajectory and eliminate the range error. A unique control law is reported that combines elliptic ballistic theory and control mode for lateral pulse jets. The impact point is directly controlled and rocket dispersion in the longitudinal direction is efficiently reduced.

Dynamic Analysis and Control of a Planar IT-SOFC System

2009 ◽  
Author(s):  
A. Salogni ◽  
P. Iora ◽  
S. Campanari
Keyword(s):  
Steady State ◽  
Fuel Cell ◽  
Dynamic Model ◽  
Characteristic Curve ◽  
Cell System ◽  
Internal Reforming ◽  
Internal Cell ◽  
Layer Region ◽  
Air Channels ◽  
And Control

This paper analyzes the dynamic behaviour of a 5 kW fuel cell system based on planar co-flow Intermediate Temperature Solid Oxide Fuel Cell (IT-SOFC) stack, with internal reforming. The system is composed by the SOFC stack, a combustor of the cell exhausts, two heat exchangers for fuel and air preheating and the related control valves, where the air temperature at the stack exit and the fuel utilization is controlled by means of a PI (proportional integral) device. The model of the stack is based on a lumped parameters dynamic model of a single cell, which is composed of the fuel and air channels, the electrochemically active three layer region representative of the anode, the cathode and the electrolyte. The stack model is first used here for a qualitative steady-state validation, reproducing the cell characteristic curve. Then it is presented the dynamic model of the system, which has been implemented using an a-causal software based on the open-source Modelica modelling language, which allows for future integration in complex power-plant configurations. After a description of the plant layout and of the dynamic model, we present and discuss the results obtained by applying the PI controls to different load changes and with different tuning of the controller parameters, evidencing the amplitudes of load changes, the extent of the transient phase to the new steady-state conditions, the internal cell temperature distribution and the thermal gradients along the PEN structure, giving the possibilities to adapt the control system to the requirements of specific SOFC technologies.

scholarly journals Topoisomerases I and II facilitate condensin DC translocation to organize and repress X chromosomes in C. elegans

2021 ◽  
Author(s):  
Ana Karina Morao ◽  
Jun Kim ◽  
Daniel Obaji ◽  
Siyu Sun ◽  
Sevinc Ercan
Keyword(s):  
Long Range ◽  
X Chromosome ◽  
Molecular Motors ◽  
Topoisomerase Ii ◽  
Dna Looping ◽  
Loop Formation ◽  
X Chromosomes ◽  
C Elegans ◽  
And Control

Condensin complexes are evolutionarily conserved molecular motors that translocate along DNA and form loops. While condensin-mediated DNA looping is thought to direct the chain-passing activity of topoisomerase II to separate sister chromatids, it is not known if topological constraints in turn regulate loop formation in vivo. Here we applied auxin inducible degradation of topoisomerases I and II to determine how DNA topology affects the translocation of an X chromosome specific condensin that represses transcription for dosage compensation in C. elegans (condensin DC). We found that both topoisomerases colocalize with condensin DC and control its movement at different genomic scales. TOP-2 depletion hindered condensin DC translocation over long distances, resulting in accumulation around its X-specific recruitment sites and shorter Hi-C interactions. In contrast, TOP-1 depletion did not affect long-range spreading but resulted in accumulation of condensin DC within expressed gene bodies. Both TOP-1 and TOP-2 depletions resulted in X chromosome transcriptional upregulation indicating that condensin DC translocation at both scales is required for its function in gene repression. Together the distinct effects of TOP-1 and TOP-2 on condensin DC distribution revealed two distinct modes of condensin DC association with chromatin: long-range translocation that requires decatenation/unknotting of DNA and short-range translocation across genes that requires resolution of transcription-induced supercoiling.

Sign in / Sign up

Export Citation Format

Share Document