Overview on Study on Properties of Concrete Canvas

Since there is expeditious increase in the materials extensively used in construction, there is a great demand for construction materials in the current generation to follow different conventional methods. There is no provision for very quick and workable concrete installation procedures in the event of an emergency. Concrete as a construction material is well-known around the world, but the hunt to improve its flexibility has always piqued researchers' interest. Although concrete has many advantages, one disadvantage is that it is not flexible when hardened. The rising cost of repair work as a result of weathering, ground surface damage, and seepage in water canals has always been a source of concern. Concrete cloth, a new technology that removes faults from concrete and is flexible and simple to apply, has been invented. Concrete Canvas has a ceramic property which is semi rigid that makes it fire resistant and water proof.

Identification of Optimal Process Parameters in Electro-Discharge Machining Using ANN and PSO

Electrical Discharge Machining (EDM) process is a widely used machining process in several fabrication, construction and repair work applications. Considering Pulse-On Time, Pulse OFF time, Peak-Current and Gap voltage as the inputs and among all possible outputs, in the present work Material Removal Rate and Surface Roughness are considered as outputs. In order to reduce the number of experiments Design of Experiments (DOE) was undertaken using Orthogonal Array and later on the outputs were optimized using ANN and PSO. It was found that the results obtained from both the techniques were tallying with each other.

Evaluation of Polymer Modified Mortar and Bonding Agent for Structural Repair

Polymer modified mortar is found to be suitable for structural repair and strengthening of damage structural elements. Conventional mortar is not preferred in repair of concrete since it has inferior mechanical property and durability performance. Polymer based mortar is an alternative to conventional mortar with enhanced mechanical properties. However, there are limited specifications and guidelines available for specifying PMM mixes for structural repair work. The research work aims to evaluate the mechanical performance of polymer based mortar with varying concentration of styrene butadiene rubber latex at laboratory scale. Another aspect in repair of corrosion damage structures is the bond between the substrate concrete and repair mortar. In order to study the effectiveness of bonding agents, the performance evaluation of bonding agents has been evaluated using slant shear test and pull-off test as per ASTM C 882 and EN 1542 respectively. Findings of study indicates that at 8-10 percent concentration of dry polymer solid by cement mass in polymer based mortar is the optimum dosage. Styrene-butadiene rubber based polymer mortar showed improvement in flow in comparison to normal mortar however, mixes with crushed sand shows decrease in flow which is due to presence of more fines. Slant shear and pull-off test method shows epoxy bonding agent give better bond strength as compared to SBR latex.

The Digital Twin for Agricultural Machinery Restoration Processes

Introduction. Agricultural machinery provides the required level of mechanization. Sand abrasive, dirt, and open-air operations considerably accelerate the wear of mechanisms. An improper work plan and lack of complete information about the state of specific equipment units increase the time for repair and maintenance operations. The purpose of the study is to develop a digital twin model for the repair and restoration system of enterprises. The model will reduce material costs and allow for the best solutions to organize the work. Materials and Methods. The model is developed on the basis of simulation modeling. The authors used the approach based on discrete-event modeling with the logical-mathematical apparatus for describing events occurring in a real object. Results. Information support is formed taking into account the parameters of the production systems of repair enterprises and a mathematical model, which is a digital twin of the production system. This approach made it possible to automate the development of optimal plans for organizing repair work by repair enterprises, taking into account their interrelationships. Discussion and Conclusion. The digital twin for the generalized production system of repair organizations allows developing options for the resource allocation and verifying them promptly to choose the best options through accumulating information about the most successful solutions. This will reduce the time for repair and restoration works, improve their quality and save labor.

The Basics of Developing an Alternative Concept for Commercial and Military Vehicle Operation (Random Strategy)

The efficiency of commercial automobiles and wheeled military vehicles mainly depends on the choice of maintenance (M) and current repair (CR) concept. In the paper the difficulties of adapting the (M) and (CR) planning strategies to the structural characteristics of modern transport facilities are pointed out. The advantages of using the (M) and (CR) random strategy for transport facilities based on the stochastic nature of failures and malfunctions are substantiated. Considering the failures and malfunctions as random values and identifying the patterns of their distribution based on γ percentage resources, it is proposed to develop a list of regulated maintenance and repair work, periodicity and labor intensity based on a random strategy, which will increase the efficiency of preserving the technical resource of the rolling stock throughout the entire life cycle of the vehicle.

STRESS-DEFORMED STATE OF THE FOUNDATION OF HYDRAULIC STRUCTURES AT CONTROLLED COMPENSATION DISCHARGE

Nnumerical simulation of the process of injection of mortar into the thickness of the sandy base during the work on lifting and leveling the structure by the method of compensatory injection is carried out. An author's program has been developed that implements the finite element method (FEM) in a spatial formulation, taking into account the elastic-plastic nature of soil deformation, in which a special element in the form of a spheroid has been developed to describe the expanding area at the location of the injector, which changes its volume during the injection of mortar. During the verification of the program, the results of mathematical modeling were compared with the data of a physical experiment conducted by PhD Luca Masini from the University of La Sapienza (Rome, Italy). Numerical modeling of the stress-strain state of the base of the structure during repair work is considered by the example of lifting the foundation plate of the Zagorskaya PSPP-2. A number of tasks are being solved related to minimizing the number of injection columns, their location, the pitch of the cuffs, the selection of portions of the injected solution, taking into account the requirements for uniform lifting of the foundation plate in order to avoid additional cracking.

Voyages of maintenance: Exploration, infrastructure, and modernity on the Krusenstern–Lisianskii circumnavigation between Russia and Japan from 1803 to 1806

Against the common association of voyages of exploration with discovery and the arrival of modernity, this essay argues that maintenance and repair were essential to the success of such voyages and that maintenance and innovation are best seen as fundamentally integrated. Using the Russian circumnavigatory voyage of Adam von Krusenstern and Urey Lisianskii in 1803–7 as a case study, the essay explores the diverse forms and roles of infrastructure and repair work in enabling a voyage of exploration, and reveals the tensions and debates that considerations of maintenance evoked among ships’ officers, crews, and the peoples they encountered.

Prerequisites for developing an advanced welding technology for repair of worn elements of steam-conducting systems

The main disadvantage of standard technologies of welding steam pipelines of thermal power plants is that they can allow the presence of defective structures close to the defective ones in the metal of the seam and in the sections of the HAZ. In this regard, the question arises about the development of a new technology that will provide the appropriate structure and properties that will increase the service life of steam pipelines and get a significant economic effect. Goal. The goal is improvement of the technology of welding pipelines of thermal power plants based on the study of the features of the formation of welded joints operating in Creep conditions. Methodology. The level of wear of the elements of the Steam-conducting path was estimated taking into account the provisions of the regulatory documentation of metallographic analysis, determination of chemical composition and properties, as well as the degree of their deformation. Results. It is revealed that welded joints are characterized by initial structural heterogeneity, which is closely related to long-term strength, ductility and impact strength. For example, at different sections of a welded joint, there is a different intensity of transition of alloying elements and, accordingly, a different type of structural component can be formed. The proposed technology of welding repair of damaged elements of steam pipelines using mechanized welding in CO2+Ar provides for the production of welded joints with a higher level of uniformity of structure, chemical composition and properties. Scientific novelty and practical significance. The welding technology has been improved, which includes developing the modes for performing repair work by mechanized welding in an Ar + CO2 environment of steam pipeline samples with a depth of ≥ 20 mm and a width of ≥ 30 mm, and differs from the known ones by using linear energy welding of 1.2–1.5 MJ/m.

Efficient and Comprehensive Integrity Diagnostics for Dual Completion String Wells, Using Spectral Noise Analyzer Tool

Well operators often face various technical challenges when intervening and repairing older, mature field wells. The most common problem associated with aging wells are tubing and casing integrity. Uncertain sources of downhole leaks and data ambiguity often lead to incorrect diagnostics that can hinder repair work or even contribute to additional or worsened integrity issues. Operators continuously challenge service companies and technology providers to drive innovation. One such challenge is in finding efficient and comprehensive integrity diagnostics for dual-string wells. A basic and general diagnostic method to verify well integrity in dual-string wells involves setting plugs in the long and short strings and pressure testing the tubings. These operations are generally time consuming, and the test data does not usually pinpoint the location of the leak, if any. Since 2016 a new diagnostic solution for this challenge has been implemented using a slickline-deployed passive acoustic logging technique. Carefully designed intervention planning, combined with efficient data acquisition, led to significant time saving and improved data quality. A more complete assessment of the integrity of both strings is now more frequent and often necessary, while challenging the conventional thinking of having to assess the lower string only while assuming the upper string is in good condition. However, investigating dual-string integrity with uncertainty on the source of leak, restrictions on facilities and limitations on surveillance time will often waste more time and money if not approached carefully. This paper discusses two case studies, including a dual-string oil producer in the South China Sea that had sustained pressure in production casing annulus. The well operator initially considered that the long string had an integrity issue, while the short string did not, based on their surface-based annulus pressure diagnostics. Consequently, the operator decided to diagnose only the long string. The passive acoustic memory tool. combined with a fast-response temperature and spinner used for the diagnosis, identified a possible short string leak while logging through the long string. This result clearly demonstrated that surface analyses can be misleading, and a comprehensive downhole diagnostic should be the recommended method to identify leaks, especially in dual-string completions. This well operator has completed more than 100 integrity diagnostic runs in the last five years. The passive acoustic diagnostic interventions have resulted in an average 50-percent time saving compared to legacy methods, and data analysis results have led to significant improvements in well productivity.

Determination of parameters of surface defects for quality control of repair work on submerged crossings

Внутритрубная диагностика позволяет обеспечить высокую выявляемость поверхностных трещиноподобных дефектов стенки трубопровода. Для их устранения в условиях проведения ремонтных работ на подводных переходах магистральных нефте- и нефтепродуктопроводов традиционно используется установка герметизирующей камеры, изолирующей дефектный участок и позволяющей в полной мере провести обследование области с опасным дефектом и дальнейший ремонт с применением методов неразрушающего контроля. Данная технология является безальтернативной, когда требуется вырезка-вварка катушки или другая сварочно-монтажная операция, однако представляется избыточной для устранения поверхностного дефекта методом вышлифовки. Современные технологии позволяют устранить поверхностный трещиноподобный дефект без установки герметизирующей камеры и тем самым значительно уменьшить трудоемкость и стоимость ремонта. Однако их широкое применение сдерживается отсутствием технической возможности проведения контроля качества отремонтированного участка под водой методами неразрушающего контроля с эквивалентной чувствительностью и выявляемостью относительно обычных условий. В этой связи выполнены экспериментальные исследования с целью определения пороговых значений параметров поверхностных трещиноподобных дефектов, выявляемых методами неразрушающего контроля в подводных условиях с учетом качества зашлифованной поверхности. Такие значения получены, в частности, для метода ультразвукового контроля с технологией фазированной решетки, модуляционного метода контроля с использованием вихретоковой матрицы, люминесцентного магнитопорошкового метода. Сформулированы требования к характеристикам оборудования для проведения неразрушающего контроля в условиях подводных работ. In-line diagnostics makes it possible to secure high detectability of surface crack-like defects of the pipeline wall. To eliminate them in conditions of repair work performed on submerge crossings of main oil and oil products pipelines, the installation of a sealing chamber is traditionally used to isolate the defective area and to enable a full-investigation of the area with a hazardous defect and further repairs, by non-destructive testing methods. This technology has no alternatives when cutting and welding of the coil or other welding and assembly operation is required, but it seems redundant for elimination of a surface defect by grinding method. Modern technologies make it possible to eliminate a surface crack-like defect without installing a sealing chamber and thereby can substantially cut manpower input and cost of repair. Their widespread use is deterred by the lack of technical possibility for quality control of the repaired area under water by nondestructive testing methods with equivalent sensitivity and detectability versus the normal conditions. In this regard, experimental research has been conducted to determine the threshold values of the parameters of surface crack-like defects detected by non-destructive testing methods in submerged conditions, taking into account the quality of the sanded surface. Such values were obtained, in particular, for the ultrasonic testing method with phased array technology, the modulation control technique using eddy current matrix, and the luminescent magnetic powder method. Requirements to performance characteristics of equipment for nondestructive testing in submerged operations have been formulated.