scholarly journals Grouting mortar for annular injection

2018 ◽  
Vol 251 ◽  
pp. 01004 ◽  
Author(s):  
Olga Lyapidevskaya
Keyword(s):  
Comparative Analysis ◽  
Laboratory Tests ◽  
Field Tests ◽  
Annular Space ◽  
Construction Work ◽  
High Quality ◽  
New Material ◽  
Materials Used ◽  
Bentonite Clays ◽  
Improved Characteristics

In conditions of cramped urban development, trenchless methods of laying engineering communications are used for environmental protection. Currently, the most widespread is shield driving with tunneling complexes. However, during construction work voids and crevices may form between the shell of the shield and the tunnel lining. In order to fill these voids and create a durable waterproof screen around the lining, the technology of injecting grouting mortars in the annular space is applied. The article shows the results of laboratory tests and gives a comparative analysis of applied grouting mortars based on mineral binders. A new composition of a grouting mortar with improved characteristics including Portland cement and bentonite clays is proposed. The results of laboratory tests of a new material are presented. Data are given that indicate the advantages of using bentonite powders for the preparation of grouting compositions over other materials used as protective injection mortars. The article contains information about field tests of the developed material, which show that the proposed grouting mortar is characterized by high rheological properties and allows obtaining a high-quality waterproof shell in the annulus.

scholarly journals Comparison analysis of using micrometers and strain gauges for measuring deformations and loads in the method of monitoring the stress-strain state

2021 ◽  
Vol 18 (3) ◽  
pp. 71-75
Author(s):  
M. O. Lobovskiy ◽  
◽  
A. L. Tukkiya ◽  
P. A. Pyatkin ◽  
◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Strain Gauge ◽  
Laboratory Tests ◽  
Strain State ◽  
Field Tests ◽  
Strain Gauges ◽  
Construction Site ◽  
Comparison Analysis ◽  
Stress Strain ◽  
Stress Strain State

The micrometer method for measuring deformations and loads in bar elements has proved to be effective not only in laboratory tests, but also in field tests on a real construction site. Having carried out a comparative analysis of the method proposed by the authors for monitoring the stress-strain state (SSS) with the strain gauge method which is widely used at present, the authors have proved that the method for measuring deformations and loads using a micrometer is not inferior in accuracy to the strain gauge method, although it is much cheaper.

scholarly journals ANALYSIS AND IMPROVEMENT OF THE SYSTEM OF CONTROL OF MATERIAL FEEDING IN FDM 3D PRINTERS

2020 ◽  
pp. 78-81
Author(s):  
S. S. Shemelyunas ◽  
A. V. Omarov ◽  
A. V. Drobotov
Keyword(s):  
Control System ◽  
Comparative Analysis ◽  
Control Systems ◽  
Advantages And Disadvantages ◽  
Feed Control ◽  
New Material ◽  
3D Printers ◽  
Improved Characteristics

A comparative analysis of feed control systems in FDM 3D printers is carried out, their advantages and disadvantages are noted. The design is proposed and the principle of operation of a new material delivery control system with improved characteristics is described.

COGNITIVIZATION — THE NEXT STAGE OF INFORMATIZATION OF EDUCATION

2018 ◽  
pp. 5-11
Author(s):  
A. S. Christochevskaya ◽  
S. A. Christochevsky
Keyword(s):  
Comparative Analysis ◽  
Learning Resources ◽  
Technical Base ◽  
Initial Stage ◽  
New Knowledge ◽  
Good Material ◽  
E Learning ◽  
New Material ◽  
High Level ◽  
Paper Method

Informatization of education has been going on for 30 years. During this time, a good material and technical base appeared in schools, there are repositories of e-learning resources to which teachers have access. However, it is difficult to use these e-learning resources due to their too large number and not always high level. It is advisable to introduce a system of reviews and recommendations, to conduct a comparative analysis, as well as to make reviews of resources on a particular subject/topic. In addition, the demand for e-learning resources is affected by the fact that education authorities encourage not so much the use of e-learning resources as their development by the teacher himself. In general, the load on teachers has increased instead of the promised saving of time and effort when using the e-learning resources. At the same time, many e-learning resources are not very effective, since they do not meet the requirements of cognitiveness (they contribute not to learning, but to simple memorization of the material). It is necessary to explore the process of learning new material: this will allow you to create cognitive e-learning resources and other resources that would help you with equal probability to successfully acquire new knowledge for students belonging to different psycho-types. At the initial stage of the study of any subject, it is more expedient to use the usual “paper” method, that is, a textbook and not overload the student’s brain with excessive information. Only when he has mastered the basic provisions, we can turn to e-learning resources, bearing in mind that they must be cognitive, that is, they are aimed at logical perception and rapid intuitive learning, only in this case e-learning resources can be considered effective. The conclusion is formulated that cognitiveness is the next stage of informatization of education after the stage of electronization.

Assessment of the quality of opening of soil structures technical means developed in Kuban State Agrarian University

2020 ◽  
Author(s):  
B. F. Tarasenko B. F. ◽  
◽  
S. Y. Orlenko S. Y. ◽  
V. V. Kuzmin V. V.
Keyword(s):  
Comparative Analysis ◽  
Field Tests ◽  
Soil Structures ◽  
Improved Design

The article presents a comparative analysis, based on field tests, of the quality of loosening of soil structures of the upper horizon with technical means developed at KubSAU and an improved design of a universal tillage unit.

Qualitative anatomical restoration of the contact point of teeth – prevention of localized forms of periodontal diseases

2020 ◽  
Vol 25 (1) ◽  
pp. 10-15
Author(s):  
L. Yu. Orekhova ◽  
O. V. Prokhorova ◽  
V. Yu. Shefov
Keyword(s):  
Comparative Analysis ◽  
Computer Simulations ◽  
Periodontal Diseases ◽  
Contact Point ◽  
Clinical Stage ◽  
High Quality ◽  
Cross Sectional ◽  
Clinical Stages ◽  
Anatomical Restoration ◽  
Approximal Surfaces

Relevance. The restoration of a high-quality anatomical and functional contact point of teeth plays an important role in preventing the development of localized forms of periodontal disease.Purpose. Development of recommendations for qualitative anatomical restoration of the contact point of teeth for the prevention of localized forms of periodontal diseases.Materials and methods. In our study, which consisted of pre-clinical and clinical stages, were analyzed 50 CT scan of the chewing group teeth calculated the ratio of approximal surfaces of molars and premolars to the width of their crowns and computer simulations of the results of restoration of contact point. We also conducted a comparative analysis of wedges of different material with different cross-sectional shapes. At the clinical stage, the restoration of the contact point of teeth in patients according to our recommendations was carried out.Results. On the basis of the data obtained during the study, a formula for calculating the height and size of the restored contact point was compiled. Recommendations for anatomical restoration of the contact point are formulated.Conclusion. The application of the recommendations developed by us allows anatomically qualitatively restore the contact point and prevent the development of localized periodontal diseases.

Laboratory Investigation of Pavement Backfilling Materials for Micro-Trenching in Cold Regions

2018 ◽  
Vol 2672 (12) ◽  
pp. 62-71
Author(s):  
Leila Hashemian ◽  
Vinicius Afonso Velasco Rios ◽  
Alireza Bayat
Keyword(s):  
Laboratory Investigation ◽  
Dynamic Modulus ◽  
Laboratory Tests ◽  
Hot Mix Asphalt ◽  
Cement Grout ◽  
Host Material ◽  
High Quality ◽  
Cold Temperatures ◽  
Asphalt Mixes ◽  
Freeze Thaw

This study investigated the performance of different materials in a micro-trench composite backfilling design. Laboratory tests were conducted to evaluate the effect of cold temperatures and freeze/thaw cycles on a cement grout and seven preparatory cold asphalt mixes. To compare the performance of cold mix asphalt and epoxy grout with hot mix asphalt as the host material, rutting tests and dynamic modulus tests at different loading frequencies and temperatures were conducted. Finally, laboratory scale micro-trench samples were prepared using different backfilling materials and were loaded using a wheel tracker after freeze/thaw conditioning. The results showed that cement grout could effectively be used to secure the conduit inside the trench. It was also concluded that using high-quality cold mix asphalt, a compatible material with hot mix asphalt, could improve micro-trench durability compared with epoxy grout.

scholarly journals Environmentally Friendly, High-Performance Fire Retardant Made from Cellulose and Graphite

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2400
Author(s):  
Leandra P. Santos ◽  
Douglas S. da Silva ◽  
Thais H. Morari ◽  
Fernando Galembeck
Keyword(s):  
High Performance ◽  
Raw Materials ◽  
Fire Retardant ◽  
Visual Observation ◽  
Flame Resistance ◽  
New Developments ◽  
New Class ◽  
New Material ◽  
Accredited Laboratory ◽  
Materials Used

Many materials and additives perform well as fire retardants and suppressants, but there is an ever-growing list of unfulfilled demands requiring new developments. This work explores the outstanding dispersant and adhesive performances of cellulose to create a new effective fire-retardant: exfoliated and reassembled graphite (ERG). This is a new 2D polyfunctional material formed by drying aqueous dispersions of graphite and cellulose on wood, canvas, and other lignocellulosic materials, thus producing adherent layers that reduce the damage caused by a flame to the substrates. Visual observation, thermal images and surface temperature measurements reveal fast heat transfer away from the flamed spots, suppressing flare formation. Pinewood coated with ERG underwent standard flame resistance tests in an accredited laboratory, reaching the highest possible class for combustible substrates. The fire-retardant performance of ERG derives from its thermal stability in air and from its ability to transfer heat to the environment, by conduction and radiation. This new material may thus lead a new class of flame-retardant coatings based on a hitherto unexplored mechanism for fire retardation and showing several technical advantages: the precursor dispersions are water-based, the raw materials used are commodities, and the production process can be performed on commonly used equipment with minimal waste.

scholarly journals Numerical Analysis on Performance of the Middle-Pressure Jet Grouting Method for Ground Improvement

Geosciences ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 313
Author(s):  
Shinya Inazumi ◽  
Sudip Shakya ◽  
Takahiro Komaki ◽  
Yasuharu Nakanishi
Keyword(s):  
Life Cycle ◽  
Comparative Analysis ◽  
Ground Improvement ◽  
Cement Slurry ◽  
Mechanical Agitation ◽  
High Quality ◽  
Jet Grouting ◽  
Computer Aided ◽  
Improvement Method ◽  
Cae System

This study focused on the middle-pressure jet grouting method, which has a complicated development mechanism for the columnar soil-improved body, with the aim of establishing a computer-aided engineering (CAE) system that can simulate the performance on a computer. Furthermore, in order to confirm the effect of middle-pressure jet grouting with mechanical agitation and mixing, a comparative analysis was performed with different jet pressures, the development situation was visualized, and the performance of this method was evaluated. The results of MPS-CAE as one of the CAE systems showed that the cement slurry jet ratio in the planned improvement range, including the periphery of the mixing blade, by the middle-pressure jet grouting together with the mechanical agitation and mixing was increased and a high quality columnar soil-improved body was obtained. It is expected that the introduction of CAE will contribute to the visualization of the ground, and that CAE will be an effective tool for the visual management of construction for ground improvement and the maintenance of improved grounds during the life cycle of the ground-improvement method.

scholarly journals Point Load Test of Half-Cylinder Core Using the Numerical Model and Laboratory Tests: Size Suggestion and Correlation with Cylinder Core

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Fengyu Ren ◽  
Huan Liu ◽  
Rongxing He ◽  
Guanghui Li ◽  
Yang Liu
Keyword(s):  
Numerical Model ◽  
Laboratory Tests ◽  
Failure Load ◽  
Field Tests ◽  
Point Load ◽  
Diameter Ratio ◽  
Load Test ◽  
Index Test ◽  
Point Load Test ◽  
Calculation Procedures

The point load test (PLT) is intended as an index test for rock strength classification or estimations of other strength parameters because it is economical and simple to conduct in the laboratory and in field tests. In the literature, calculation procedures for cylinder cores, blocks, or irregular lumps can be found, but no study has researched such procedures for half-cylinder cores. This paper presents the numerical model and laboratory tests for half-cylinder and cylinder specimens. The results for half-cylinder and cylinder specimens are then presented, analysed, and discussed. A correlation of failure load between half-cylinder and cylinder specimens is established with a suitable size suggestion and correction factor. It is found that the failure load becomes stable when half-cylinder specimens have a length/diameter ratio higher than 0.9. In addition, the results show that the point load strength index (PLSI) of half-cylinder cores can be calculated using the calculation procedures for diametral testing on cylinder cores, and it is necessary to satisfy the conditions that the length/diameter ratio be higher than 0.9 and the failure load be multiplied by 0.8.

The Study of Specific Materials Used by the Copper Wiring CMP of GLSI

2013 ◽  
Vol 307 ◽  
pp. 368-371
Author(s):  
Yu Ling Liu ◽  
Juan Wang ◽  
Bao Hong Gao
Keyword(s):  
High Speed ◽  
Chelating Agents ◽  
Active Agent ◽  
Copper Ion ◽  
Copper Film ◽  
Steel Corrosion ◽  
New Material ◽  
Ph Buffer ◽  
Materials Used ◽  
Acidic Oxides

In this paper, the multi-hydroxyl polyamines researched by ourselves are used in the slurry of the copper wiring CMP of GLSI, which makes the slurry alkalization. It also has the using as a pH adjusting agent, complexion agent of copper ion, multi- metal chelating agents, aminating agent of acidic oxides, pH buffer, stainless steel corrosion inhibitor, the active agent and pro-oxidant. It improves the property of slurry and solves many different of acidity slurry. The alkalinity slurry contained the multi-hydroxyl polyamines is environmental, inexpensive and composition- simplified. Without the toxic BTA which is must be used in the international and has side effect, the slurry can achieve the high speed and high flat. In the same time the low pressure and the little abrasive can be realized, which provide the new material for the removal of TSV copper film.

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