scholarly journals Experimental Study on the Complex Contact Frictional Property of an Ultralong Distance Large-Section Concrete Pipe Jacking and Prediction of Pipe String Stuck

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Ziyong He ◽  
Jiangong Chen
Keyword(s):  
Contact Surface ◽  
Frictional Resistance ◽  
Test Method ◽  
Frictional Property ◽  
Test Results ◽  
Long Distance ◽  
Bentonite Slurry ◽  
Pipe Jacking ◽  
Jacking Force ◽  
Variation Trends

Line 2 of the Guanjingkou Pipe Jacking Project in Chongqing encountered a pipe sticking problem, whose occurrence was inevitably attributed to the higher total frictional resistance of pipe strings rather than the maximum jacking force. Line 1, which is about to start construction, has basically the same construction environment as Line 2 using the same microshield and pipe string sizes. To avoid repeating the pipe sticking problem of Line 2, the mutual friction characteristics between the surrounding rocks and jacked pipe strings are studied for Line 1 by adopting the same test method under seven complex contact conditions (the presence or various combinations of three substances, i.e., extrapipe string field debris, bentonite slurry, and sand-laden waste slurry, on the jacked pipe string-surrounding rock contact surface are mainly considered). The results show that sufficient bentonite slurry can effectively reduce the frictional resistance, and when the amount of bentonite is insufficient, the average friction coefficient (AFC) of the later contact surface increases by 50%∼70%. The comparison of the monitored versus predicted jacking forces indicates that the value predicted by the test is slightly higher than the monitored force and the variation trends of the two match well, thus proving the correctness of the test results. It is possible to continue predicting the variation trends of the jacking force and frictional resistance based on the contact situation outside the pipe string wall, which greatly lowers the probability of re-encountering pipe sticking. The test results not only explain the important role of bentonite slurry in reducing the pipe string wall frictional resistance but also suggest that an increase in the pipe string wall frictional resistance resulting from the complex contact inflow into the overexcavation gap is the root cause of pipe sticking; moreover, the number of jacked pipe strings matching a single IJS is the second cause of pipe string sticking. The methodology of this study can provide a reference for other studies concerning the jacking force of long-distance rock microshield tunnelling.

scholarly journals Research on the Slurry for Long-Distance Large-Diameter Pipe Jacking in Expansive Soil

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Xian Yang ◽  
Yang Liu ◽  
Chao Yang
Keyword(s):  
Large Diameter ◽  
Soil Layer ◽  
Expansive Soil ◽  
Expansion Ratio ◽  
Water Dissociation ◽  
Long Distance ◽  
Calculating Method ◽  
Water Based ◽  
Pipe Jacking ◽  
Jacking Force

When the pipe jacking technology is applied in expansive formation, the soil around the pipe will easily absorb water from the slurry and expand to wrap up the pipe, producing an excessive pipe jacking force. A water-based slurry formula suitable for pipe jacking in expansive soil layer was proposed in this paper. Firstly, the key design points of pipe jacking slurry in expansive soil were put forward. Secondly, plant glue, potassium humate, Na-CMC, and graphite powder were chosen as treating agents to improve the slurry performance. The effect of addition levels of different treating agents on the funnel viscosity, filter loss, expansion ratio, friction coefficient and water dissociation rate of the slurry were tested. Thirdly, based on the results of single-factor tests, a water-based slurry formula suitable for pipe jacking in expansive soil was obtained. Finally, the slurry formula was applied in a practical pipe jacking project in expansive formation, and the jacking force was controlled well in the whole jacking process. The new water-based slurry is cheap and practical and has no pollution to environment. Furthermore, a simple and practical calculating method of the pipe jacking force was presented. The comparison of the calculated and measured pipe jacking force shows that the simple calculating method can estimate the jacking force well. Improving slurry performance to reduce jacking force in pipe jacking and predicting pipe jacking force accurately can help reducing the investment for counterforce wall and jacking system in pipe jacking engineering.

The Research of IC Test Based on LTX-77 Test System

2014 ◽  
Vol 496-500 ◽  
pp. 1176-1179
Author(s):  
Li Tan ◽  
Yu Fang
Keyword(s):  
Test Object ◽  
Test System ◽  
Test Method ◽  
Test Results ◽  
Analog Ic ◽  
Test Platform ◽  
Logic Functions ◽  
Actual Test ◽  
Ic Test

LTX-77 test system is a large IC test system that is used for various kinds of analog IC, digital IC and analog digital mixed IC. It can be used to test DC parameters, AC parameters and logic functions. In the paper, the IC test platform is LTX-77 test system. IC ADC0804 was tested as the test object. The test method of IC is described in the view of actual test. The test results show that the test system is convenient and accurate, which has important practical value for IC manufacturers and users.

The Improved Friction Properties of Bonded MoS2 Films by MAO Treating of Al Substrate

2013 ◽  
Vol 275-277 ◽  
pp. 1911-1914 ◽  
Author(s):  
Han Jun Hu ◽  
Hui Zhou ◽  
Yu Gang Zheng ◽  
Kai Feng Zhang ◽  
Zhi Hua Wan
Keyword(s):  
Tribological Properties ◽  
Solid Lubricants ◽  
Ceramic Coatings ◽  
Test System ◽  
Test Method ◽  
Test Results ◽  
Specimen Test ◽  
Micro Arc Oxidation ◽  
A New Technique ◽  
Porous Microstructures

The bonded MoS2 films are widely used as solid lubricants in aerospace mechanisms due to their excellent tribological properties. Traditionally, the MoS2 was directly bonded on the Al substrate that was only treated by the technique named of sandblast. For improving the tribological properties of MoS2 films, micro arc oxidation (MAO) instead of sandblast was introduced as a new technique for treating of Al substrate. In this article, the tribological properties of MoS2 films which were bonded on different surface of Al substrate as mentioned above were discussed, respectively. It was concluded from the test results that the MoS2 films bonded on substrate treated by MAO have better tribological properties than those samples treated by sandblast. The endurance life against abrasion of the former is as high as twenty times of the latter by the stand test method of ball on disk using the UMT Multi-Specimen Test System. This test results could be illustrated by the following reasons. The first is the porous microstructures of MAO ceramic coatings on the Al substrate. The coatings have numerous pits to be good at increasing the binding force with the MoS2 films, and the pits can also provide a MoS2 lubricants reservoir during processes of friction. Both of them improved the MoS2 film’s ability of wear-protective. The second is that hardness of the coating is higher than the Al, and this ensures well wearing resistance, especially in practical application to big load-supporting moving parts, such as bearing, gear, etc…

Study on Conventional Domed Bursting Disc Material and Burst Pressure Test

2013 ◽  
Vol 690-693 ◽  
pp. 2371-2378
Author(s):  
Wei Pu Xu ◽  
Yi Ting Liu
Keyword(s):  
Stainless Steel ◽  
Tensile Test ◽  
316L Stainless Steel ◽  
Performance Test ◽  
Test Method ◽  
Burst Pressure ◽  
Test Results ◽  
Manufacturing Method ◽  
Pressure Test ◽  
Disc Material

A brief overview is given in the conventional domed bursting disc structure and manufacturing method. 316L stainless steel as a template is selected. With the investigation on bursting disc material tensile test method, the test results are summarized,also the burst results of disc burst pressure in different sizes. With the help of bursting disc material performance test and bursting disc burst pressure test of 316L , the test results provide a reference for other types of bursting disc.

scholarly journals Hedonic Test Method for Measuring Instant Pindang Seasoning Powder Preferences

2019 ◽  
Vol 3 (1) ◽  
pp. 34
Author(s):  
Dea Tio Mareta
Keyword(s):  
Test Method ◽  
Test Results ◽  
Drying Method ◽  
Typical Food ◽  
Hedonic Scale

Instant seasoning for cooking are commonly known by people who want something practical. Pindang is a typical food of Lampung and South Sumatra Province, consisting of various spices and herbs. Instant pindang seasoning powder made with foam mat drying method using 3 varations of foam additives. The purpose of this study was to determine the level of taste, aroma, and color of instant pindang seasoning powder made with three variations of foam additives, namely 5% (w/w), 10% (w/w), and 15% (w/w). The hedonic test for instant pindang seasoning powder were carried out on 35 panelists. Panelists were faced with 3 samples with 3 different sample numbers. Panelists were asked to assess how much preference for seasoning products using hedonic scale. The hedonic test results showed that, with the addition of 15% (w/w) foam is preferred in terms of color. As for aroma and taste, there were no significant differences between the three products. Keywords: foam mat drying , hedonic test, instant pindang seasoning powder, pindang

scholarly journals Pengaruh Latihan Dribbling With A Curving Line Trajectory Untuk Meningkatkan Keterampilan Dribbling Pemain Sepak Bola Ps. Undikam Mataram Tahun 2019

2019 ◽  
Vol 4 (4) ◽  
Author(s):  
Ismail Marzuki ◽  
Soemardiawan Soemardiawan
Keyword(s):  
Sampling Technique ◽  
Test Method ◽  
Soccer Players ◽  
Football Players ◽  
Test Results ◽  
Significance Level ◽  
Speed Test ◽  
Table Analysis ◽  
Observation Method ◽  
Line Trajectory

The focus of the problem in this research When competing frequently there are mistakes in dribbling, so from this it is necessary to have this exercise, to improve the dribbling skills of PS players. UNDIKMA Mataram. The purpose of this study is to determine whether there is an effect of Dribbling With A Curving Line Trajectory Exercise on the Dribbling Skills of PS Soccer Players. Mataram UNDIKMA 2019 ". The research methods used by researchers are the observation method, the documentation method and the deed test method. The study design uses a pretest-posttest design (initial test and final test). The population used in this study are all PS players. UNDIKMA Mataram in 2019. The number of samples in the study conducted was 22 which became a sample of 11 players PS soccer players. UNDIKMA Mataram. The sampling technique in this study using the saturation sampling technique is a sampling technique if all members of the population can be sampled. Analysis of statistical data with a significance level of 5% for the speed test results obtained by the t-value so from the results of research X1 (Dribbling With A Curving Line Trajectory, with Y1 obtained tcount is much greater than ttable, this shows that the hypothesis "Ha" (accepted ) then this research is significant, drawing conclusions from the table analysis at a significant level of 5% with a number of samples (n - 1) that is 11-1 = 10 at 1,812. Then it can be concluded that, 1) The Effect of Dribbling With A Curving Line Trajectory on Dribbling Skills PS Football Players. Mataram UNDIKMA 2019, Tcount> ttable (7.362> 1,812). 2). this shows that the hypothesis "Ha" (accepted) then this research is significant.

scholarly journals PENDIDIKAN KARAKTER MELALUI PEMBELAJARAN MATEMATIKA

2014 ◽  
Vol 10 (1) ◽  
Author(s):  
Salafudin *
Keyword(s):  
Statistical Analysis ◽  
Character Education ◽  
Sampling Technique ◽  
Problem Formulation ◽  
Test Method ◽  
Cluster Sampling ◽  
Test Results ◽  
Learning Mathematics ◽  
Character Building ◽  
Better Than

This study aimed to determine: (1) how was the design of character building by learning mathematics, and (2) whether the character building by learning mathematics could produce better learning outcome of mathematics than conventional mathematics learning.To answer these two questions, I used Research and Development ( R & D ) which consists of a preliminary study to obtain preliminary data on student learning outcomes before being given treatments of character building by learning mathematics. The next phase is the design of the character building by learning mathematics. Further testing and revision in class and repeated until it found the best learning model. From the first problem formulation, qualitative data analysis, such as the design of character building in learning mathematics was produced. The results of the qualitative analysis shows, character building by learning mathematics was quite effectively applied to implant positive character in students. To answer the second question, statistical analysis was used. The population in this study was all students of class VII of MTsN in Buaran of Pekalongan which totaled 220. By random cluster sampling technique two classes (a class VII A and VII B) was chosen. Class VII A was as an experiment class, and class VII B was as a control class. Data were taken by the test method, experimental classroom observation, and documentation. The data was then processed with an average difference test. Results of statistical analysis obtained t = 3.33 > t table = 1.67. This meant that learning achievement of the students in the experimental class, which was implemented character education in mathematics was better than the students who were taught by conventional methods. Based on these results, it could be conclude that the character building in mathematics was better than the conventional method of learning mathematics.

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