scholarly journals Analysis of the Development Characteristics and Influencing Factors of Freezing Temperature Field in the Cross Passage

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Yan Zhuang ◽  
Junhao Chen ◽  
Jian Zhang ◽  
Jianlin Wang ◽  
Han Li
Keyword(s):  
Wall Thickness ◽  
Completion Time ◽  
Measurement Data ◽  
Freezing Temperature ◽  
Cooling Capacity ◽  
Deep Soil ◽  
Sandy Silt ◽  
The Cross ◽  
The Difference ◽  
Silt Layer

Based on the analysis of the temperature measurement data of the Shanghai Metro Line 15 cross passage freezing project, it was found that the gray silt layer of cross passage No. 2 outperforms that of cross passage No. 1 on the freezing effect, which is mainly attributed to the large loss of cooling capacity in the latter passage. Within the same stratum, the soil temperature at the duct piece is higher than that of the deep soil. When the soil freezes for 45 days, the temperatures of the sandy silt and gray silt layers of the same cross passage drop to −8.25°C and −6.91°C, respectively, indicating that the freezing effect of the sandy silt layer is better than that of the gray silt layer. Moreover, simulations were performed for deviation freezing pipes, nondeviation freezing pipes, and different freezing pipe diameters in the cross passage No. 1, respectively. It was found that the maximum difference of the closure completion time between the deviation and nondeviation freezing pipes is 6 days. Furthermore, for deviation freezing pipes and nondeviation freezing pipes at the center of the cross passage, the minimum difference in the freezing wall thickness reduces from 0.45 mm after 20 days of freezing to 0.06 mm after 45 days of freezing, indicating that the difference in the freezing wall thickness gradually weakens as freezing develops gradually. The deviation freezing pipe increases the spacing of freezing pipes in the deep soil. As the pipe spacing increases, the influence of the pipe diameter on the closure completion time of the freezing wall decreases.

scholarly journals Freezing Temperature Field of FSPR under Different Pipe Configurations: A Case Study in Gongbei Tunnel, China

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Yin Duan ◽  
Chuanxin Rong ◽  
Hua Cheng ◽  
Haibing Cai ◽  
Wei Long
Keyword(s):  
Temperature Field ◽  
Freezing Temperature ◽  
Cooling Capacity ◽  
Frozen Soil ◽  
Construction Technology ◽  
Scaled Model ◽  
The Difference ◽  
Improved Design ◽  
Lower Temperature ◽  
Time Required

As a new tunnel presupport construction technology, the freeze-sealing pipe roof method (FSPR) has been successfully applied to the Gongbei Tunnel Project for the first time in China. To overcome the practical difficulties of this new method in the freezing construction process, such as welding difficulties of the profiled freezing tube, refrigerant leakage, and long construction period, based on the principle of an equal cooling capacity, an improved design of freezing tube was proposed. By designing three different pipe configurations and using scaled model tests and numerical simulation, the feasibility of the improvement and the difference in the freezing temperature field were studied. The research results show that the improved design with double circular freezing tubes exhibited a lower temperature and a higher cooling rate during the test, and the time required to meet the freezing design requirements was significantly shortened. Finally, a composite structure of “pipe roof and frozen soil curtain” with a better carrying capacity and water sealing performance was formed. It was recommended to strengthen the temperature monitoring at the pipe wall in the preliminary stage of the freezing construction to ensure the water sealing effect between the pipes. In the later stage, attention should be paid to monitoring the thickness of the frozen curtain and reducing excessive frost heave through technical means such as cooling capacity control. The improvement and configurations proposed in this research could effectively replace profiled freezing tubes in the original project, better adapt to horizontal freezing projects of similar curved tunnels, achieve the freezing goal faster, and provide a reference for the promotion of the FSPR.

scholarly journals Experimental Study of the Space–Time Effect of a Double-Pipe Frozen Curtain Formation with Different Groundwater Velocities

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3830
Author(s):  
Shicheng Sun ◽  
Chuanxin Rong ◽  
Hua Cheng ◽  
Bin Wang ◽  
Xiaogang Jiang ◽  
...  
Keyword(s):  
Freezing Temperature ◽  
Physical Model Test ◽  
Sand Layer ◽  
Test Results ◽  
Groundwater Velocity ◽  
Test Platform ◽  
The Difference ◽  
Freezing Test ◽  
Double Pipe ◽  
Thermal Physical Properties

Groundwater velocity has significant effects on the formation of a frozen curtain during freezing. In order to study the influence of the velocity on a frozen curtain, a large physical model test platform was established for double-pipe freezing. Based on this platform, freezing tests for different velocities were carried out. Quartz sand was selected as a similar material. The freezing temperature of the saturated sand layer was found by analyzing the results of the nuclear magnetic resonance (NMR). Based on the study of the thermal physical properties of the sand layer, the freezing test results were analyzed, and the results showed that the flow led to the differential development of the temperature between the upstream and downstream sections of the freezing pipes. Moreover, the larger the velocity, the greater the difference. The flow prolonged the overlapping time of the frozen curtains. Additionally, the flow slowed down the development of the frozen curtain area and the frozen curtain thickness. The larger the flow velocity, the greater the inhibition of the flow on the development of the frozen curtain. The test results can provide more references for the design and construction of freezing engineering with flowing groundwater.

scholarly journals Ce-Bearing FeSi Alloy Inoculation of Electrically Melted, Low Sulphur Grey Cast Irons for Thin Wall Castings

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1122
Author(s):  
Irina Varvara Balkan ◽  
Iulian Riposan
Keyword(s):  
Wall Thickness ◽  
Structural Characteristics ◽  
Cooling Curve ◽  
Thin Wall ◽  
Cast Irons ◽  
Iron Castings ◽  
Grey Cast ◽  
The Difference ◽  
Thermal Cooling ◽  
Fesi Alloy

Electrically melted and over-heated (>1500 °C) grey cast iron at less than 0.04%S, as commonly used, solidifies large amounts of carbides and/or undercooled graphite, especially in thin wall castings; this is necessary to achieve a stronger inoculation. The efficiency of Ce-bearing FeSi alloy is tested for lower ladle addition rates (0.15 and 0.25 wt.%), compared to the base and conventional inoculated iron (Ba,Ca-bearing FeSi alloy). The present work explores chill and associated structures in hypoeutectic grey iron (3.6–3.8%CE, 0.02%S, (%Mn) × (%S) = 0.013–0.016, Alres < 0.002%), in wedge castings W1, W2 and W3 (ASTM A 367, furan resin sand mould), at a lower cooling modulus (1.1–3.5 mm) that is typically used to control the quality of thin wall iron castings. Relatively clear and total chill well correlated with the standard thermal (cooling curve) analysis parameters and structural characteristics in wedge castings, at different wall thickness, displayed as the carbides/graphite ratio and presence of undercooled graphite morphologies. The difference in effects of the two inoculants addition is seen as the ability to decrease the amount of carbides and undercooled graphite, with Ce-bearing FeSi alloy outperforming the conventional inoculant, especially as the wall thickness decreased. It appears that Ce-bearing FeSi alloy could be a solution for low sulphur, electric melt, thin wall iron castings production.

Algorithms for Density, Potential Temperature, Conservative Temperature, and the Freezing Temperature of Seawater

2006 ◽  
Vol 23 (12) ◽  
pp. 1709-1728 ◽  
Author(s):  
David R. Jackett ◽  
Trevor J. McDougall ◽  
Rainer Feistel ◽  
Daniel G. Wright ◽  
Stephen M. Griffies
Keyword(s):  
Thermal Expansion ◽  
Equation Of State ◽  
Thermodynamic Potential ◽  
Potential Temperature ◽  
Inverse Function ◽  
Freezing Temperature ◽  
Ocean Models ◽  
The Difference ◽  
New Equation ◽  
Density Equation

Abstract Algorithms are presented for density, potential temperature, conservative temperature, and the freezing temperature of seawater. The algorithms for potential temperature and density (in terms of potential temperature) are updates to routines recently published by McDougall et al., while the algorithms involving conservative temperature and the freezing temperatures of seawater are new. The McDougall et al. algorithms were based on the thermodynamic potential of Feistel and Hagen; the algorithms in this study are all based on the “new extended Gibbs thermodynamic potential of seawater” of Feistel. The algorithm for the computation of density in terms of salinity, pressure, and conservative temperature produces errors in density and in the corresponding thermal expansion coefficient of the same order as errors for the density equation using potential temperature, both being twice as accurate as the International Equation of State when compared with Feistel’s new equation of state. An inverse function relating potential temperature to conservative temperature is also provided. The difference between practical salinity and absolute salinity is discussed, and it is shown that the present practice of essentially ignoring the difference between these two different salinities is unlikely to cause significant errors in ocean models.

Deformation distortions of geometric form tube blanks in the process of drilling holes

2021 ◽  
pp. 104-110
Author(s):  
A.N. Isaev ◽  
S.V. Vlaskin ◽  
V.A. Lebedev ◽  
M.D. Gavrilenko
Keyword(s):  
Stress State ◽  
Wall Thickness ◽  
Cross Sections ◽  
Theoretical Studies ◽  
Geometric Form ◽  
Axisymmetric Stress ◽  
Axisymmetric Stress State ◽  
Elastic Plastic ◽  
The Cross

The influence of deviations of the shape of the cross-sections of pipes from roundness on the axisymmetric stress state and taking this factor into account in theoretical studies and methods for solving problems of mandrel drilling in the elastic-plastic mode are considered. The features of the choice of tubular blanks, which help to reduce the unevenness of deformation and increase the accuracy of processing in the process of mandrel drilling, are revealed. Recommendations are given for eliminating the variance in wall thickness of blanks at the stage of their preparation for the mandrel operation.

The Field Measure of Special Strata Freezing Temperature in West Area

2012 ◽  
Vol 170-173 ◽  
pp. 1207-1210
Author(s):  
Jun Hao Chen ◽  
Rui Zhang
Keyword(s):  
Engineering Design ◽  
Freezing Temperature ◽  
Design Requirement ◽  
Shaft Sinking ◽  
Design Requirements ◽  
Security Information ◽  
Frozen Wall ◽  
The Difference ◽  
Circle Tube ◽  
Field Measure

A new round of upsurge of mine well construction were set off in the west area, but there are many problems, this article through the field measure of special strata freezing temperature in Bo-jiang-hai-zi coal mine airshaft, use the freezing shaft sinking security information network visualization platform that developed by Anhui University of Science and Technology, analysis several different strata, obtain the overall temperatre decline rate, and compare the difference between in-site shaft well temperature and the calculation value at different position, and difference is very small, it shows that the platform can good response the actual situation. Through calculation, the frozen wall thickness, average of frozen wall temperature, shaft well temperature are meet the engineering design requirement, so propose that in west area at the freezing method mine well construction, the main purpose is waterproof, and use single circle tube freezing can satisfy engineering design requirements.

scholarly journals Meditation and perception: some notes on the psychology of religious mysticism

1970 ◽  
Vol 5 ◽  
pp. 34-46
Author(s):  
Hjalmar Sundén
Keyword(s):  
Necessary Condition ◽  
Physiological Conditions ◽  
Saint John ◽  
The Subject ◽  
Mystical Experiences ◽  
The Cross ◽  
The Difference ◽  
John Of The Cross

The study of mysticism must be carried on with more attention paid to the meditative techniques used by mystics and to the problems of perception. In this paper the author presents some remarks on the difference between Saint Teresa and Saint John of the Cross, and then mentions some recent studies of meditation and some problems of perception. If meditative techniques have become of great importance in psychotheraphy, the organismic approach of the "mindcurers" and their results will permit us to complete phenomenological descriptions of mystic conscious states with more exact information of their physiological conditions. In this way "mystical experiences" in general can be seen as results of meditative techniques and we need not regard "an hysterical predisposition" of the subject as their necessary condition.

scholarly journals Development of Urban Driving Cycle with GPS Data Post Processing

2016 ◽  
Vol 28 (4) ◽  
pp. 353-364 ◽  
Author(s):  
Peter Lipar ◽  
Irena Strnad ◽  
Martin Česnik ◽  
Tomaž Maher
Keyword(s):  
Data Collection ◽  
Urban Area ◽  
Measurement Data ◽  
Driving Cycle ◽  
Gps Data ◽  
Post Processing ◽  
The Difference ◽  
Large Random Sample ◽  
Representative Area ◽  
Development Methods

This paper presents GIS-based methodology for urban area driving cycle construction. The approach reaches beyond the frames of usual driving cycle development methods and takes into account another perspective of data collection. Rather than planning data collection, the approach is based on available in-vehicle measurement data post processing using Geographic Information Systems to manipulate the excessive database and extract only the representative and geographically limited individual trip data. With such data post processing the data was carefully adjusted to include only the data that describe representative driving in Ljubljana urban area. The selected method for the driving cycle development is based on searching for the best microtrips combination while minimizing the difference between two vectors; one based on generated cycle and the other on the database. Accounting for a large random sample of actual trip data, our approach enables more representative area-specific driving cycle development than the previously used techniques.

scholarly journals Markerless Image Alignment Method for Pressure-Sensitive Paint Image

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 453
Author(s):  
Kyosuke Suzuki ◽  
Tomoki Inoue ◽  
Takayuki Nagata ◽  
Miku Kasai ◽  
Taku Nonomura ◽  
...  
Keyword(s):  
Computational Cost ◽  
Measurement Data ◽  
Image Alignment ◽  
Feature Points ◽  
Alignment Method ◽  
Pressure Sensitive Paint ◽  
Pressure Sensitive ◽  
Difference Of Gaussian ◽  
Tracing Algorithm ◽  
The Difference

We propose a markerless image alignment method for pressure-sensitive paint measurement data replacing the time-consuming conventional alignment method in which the black markers are placed on the model and are detected manually. In the proposed method, feature points are detected by a boundary detection method, in which the PSP boundary is detected using the Moore-Neighbor tracing algorithm. The performance of the proposed method is compared with the conventional method based on black markers, the difference of Gaussian (DoG) detector, and the Hessian corner detector. The results by the proposed method and the DoG detector are equivalent to each other. On the other hand, the performances of the image alignment using the black marker and the Hessian corner detector are slightly worse compared with the DoG and the proposed method. The computational cost of the proposed method is half of that of the DoG method. The proposed method is a promising for the image alignment in the PSP application in the viewpoint of the alignment precision and computational cost.

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