scholarly journals Barite-containing radiation protective building materials

2020 ◽  
Vol 21 (1) ◽  
pp. 94-98
Author(s):  
Nikolay V. Novikov ◽  
Svetlana V. Samchenko ◽  
Galina E. Okolnikova

Due to the active development of industries using nuclear technology, the creation of highly effective and cost-effective building materials for protection against hazardous ionizing radiation is of increasing interest. Widespread in the field of radiation-protective building materials are barite-containing concrete. The purpose of this article is to establish the prospects of their use in nuclear facilities, as well as to find ways to improve their technical and operational characteristics. For this an analysis of relevant literature and scientific research in the field of radiation-protective materials and, in particular, barite-containing concrete was carried out. The advantages of barite-containing concrete are high radiation-protective properties, environmental friendliness, high density, as well as economic indicators. The disadvantages are high susceptibility to shrinkage deformation and poor resistance to cyclic temperature effects. The addition of barite to the concrete composition allows to increase the coefficient of linear absorption of -rays of the material; also, with the proper selection of the composition, such material may have strength characteristics equal to or superior to the characteristics of concrete with standard compositions. Barite-containing materials have a wide range of applications and can be used both for the production of heavy concrete in the construction of load-bearing structures and in the creation of radiation-protective coatings for walls and floors.

2021 ◽  
Vol 13 (24) ◽  
pp. 13607
Author(s):  
Alexey N. Beskopylny ◽  
Sergey A. Stel’makh ◽  
Evgenii M. Shcherban’ ◽  
Levon R. Mailyan ◽  
Besarion Meskhi ◽  
...  

Improving the efficiency and quality of construction mainly depends on the cost of building materials, which is about 55–65% of total capital-construction costs. The study aimed to obtain geopolymer fine-grained concrete with improved quality characteristics that meet the construction field’s sustainable development criteria and that have environmental friendliness, economic efficiency, and advantages over competing analogues. The dependences of strength characteristics on various compositions of geopolymer concrete were obtained. It was found that the most effective activator is a composition of NaOH and Na2SiO3 with a ratio of 1:2. The increase in the indicators of the obtained geopolymer concrete from the developed composition (4A) in relation to the base control (1X) was 17% in terms of compressive strength and 24% in tensile strength in bending. Polynomial equations were obtained showing the dependence of the change in the strength characteristics of geopolymer concrete on the individual influence of each of the activators. A significant effect of the composition of the alkaline activator on the strength characteristics of geopolymer fine-grained concrete was noted. The optimal temperature range of heat treatment of geopolymer concrete samples, contributing to the positive kinetics of compressive strength gain at the age of 28 days, was determined. The main technological and recipe parameters for obtaining geopolymers with the desired properties, which meet the ecology requirements and are efficient from the point of view of economics, were determined.


2020 ◽  
Vol 175 ◽  
pp. 11022
Author(s):  
Daria Buzina ◽  
Igor Engovatov

Natural radionuclides include the 238U and 232Th radioactive families with daughter decay products and 40K potassium. In addition to these, the raw materials may contain man-made radioactive nuclides formed due to accidents at the nuclear facilities and its uncontrolled release into the environment (for example, 137Cs). Reducing the impact of radiation exposure on humans and the environment is an urgent task, both in Russia and abroad, given the rapid quantitative growth of the range, manufacturers, suppliers and consumers of building materials associated with the general trend of urbanization. Currently, there is a large number of studies on the natural and man-made radioactivity of building materials. As a rule, they present disparate and local scientific results, which complicates their accessibility to a wide range of interested parties manufacturers and consumers of construction products. Therefore, it is necessary that information on the radiation and environmental cleanliness of various materials and products was easily accessible to all comers. An information system on the natural and man-made radioactivity of building materials and products should become a tool for solving this problem. The work outlines the principles of creation and practical implementation, structure and content, goals, objectives of the field of destination and application of the information system for natural and man-made radioactivity of building materials and products.


TEM Journal ◽  
2020 ◽  
pp. 566-572
Author(s):  
Sergey A. Borisov ◽  
Yulia I. Glukhovskaya ◽  
Sergey V. Dobrovolskiy ◽  
Petr V. Nikitin ◽  
Igor V. Podporin

The article describes the creation of the concept of an experimental setup for testing the technology for the formation of new anti-corrosion coating materials using low-temperature supersonic heterogeneous flows, which allows scientific research to be carried out in a wide range of tasks of practical interest in order to create protective coatings for metal products operating under conditions of erosion and corrosion wear.


2019 ◽  
Vol 10 (3) ◽  
pp. 61-75
Author(s):  
A. V Bolotin ◽  
A. A Lunegova ◽  
G. G Zhukova ◽  
D. N Ovsyannikova

The construction industry today uses a wide range of materials, many of which were made possible thanks to advances in technology and the chemical industry. In our days, more and more often, in the construction of country houses, natural stones are preferred in the exterior decoration of buildings. In connection with the growing demand for country houses, the most popular and inexpensive material for the construction and design of facades becomes a coquina. Certain requirements are imposed on natural stones, and the values of the coquina correspond to most of them. The main requirements are aesthetic appearance, environmental friendliness, durability. Coquina is a special material, its unique properties are regulation the microclimate in the house and saturation the air with sea salt and iodine, due to its natural origin and absolute naturalness. The share of human participation in the production of coquina is limited only by cutting the stone into pieces of the required size. The only effect on the coquina is hydrophobization because the material is very hygroscopic. As a building material, coquina is used in a wide variety of areas. Coquina is perfect for the construction of exterior walls, interior partitions and decorative interior decoration. Also in construction prefer materials such as brick, foam concrete and aerated concrete. In order to understand which material is more suitable for construction, an analysis of their main characteristics is performed. The article calculates the loads that can withstand walls of coquin and brick. Also performed thermal calculation of the outer wall of the building from the coquin. Being beautiful material and having at the same time good operational characteristics, a coquina is ideally suited for construction and registration of housing.


2020 ◽  
pp. 1192-1198
Author(s):  
M.S. Mohammad ◽  
Tibebe Tesfaye ◽  
Kim Ki-Seong

Ultrasonic thickness gauges are easy to operate and reliable, and can be used to measure a wide range of thicknesses and inspect all engineering materials. Supplementing the simple ultrasonic thickness gauges that present results in either a digital readout or as an A-scan with systems that enable correlating the measured values to their positions on the inspected surface to produce a two-dimensional (2D) thickness representation can extend their benefits and provide a cost-effective alternative to expensive advanced C-scan machines. In previous work, the authors introduced a system for the positioning and mapping of the values measured by the ultrasonic thickness gauges and flaw detectors (Tesfaye et al. 2019). The system is an alternative to the systems that use mechanical scanners, encoders, and sophisticated UT machines. It used a camera to record the probe’s movement and a projected laser grid obtained by a laser pattern generator to locate the probe on the inspected surface. In this paper, a novel system is proposed to be applied to flat surfaces, in addition to overcoming the other limitations posed due to the use of the laser projection. The proposed system uses two video cameras, one to monitor the probe’s movement on the inspected surface and the other to capture the corresponding digital readout of the thickness gauge. The acquired images of the probe’s position and thickness gauge readout are processed to plot the measured data in a 2D color-coded map. The system is meant to be simpler and more effective than the previous development.


2019 ◽  
Author(s):  
Nilanjan Sengupta

Building construction sector can play a major role in reducing Greenhouse Gas emission through application of technologies aimed at reduction of use of building materials. Energy consumed during production of building materials and components plays a crucial role in creating environmental pollution. India is witnessing high growth in urban and rural housing, which needs more production of building materials. Permanent or semi-permanent type buildings which consume easily available conventional materials like brick, reinforced cement concrete etc. can be made Economic and Eco-friendly by lowering use of energy-consuming building materials through Cost-effective Construction Technologies. Buildings with Cost-effective Construction Technology can be designed within the parameters of the existing Indian Standards. Awareness generation among the users, proper technical and architectural guidance and easy availability of skilled manpower are of utmost importance for promotion of cost-effective technologies in India and to make them as the most acceptable case of sustainable building technologies both in terms of cost and environment.


The recycling and reuse of materials and objects were extensive in the past, but have rarely been embedded into models of the economy; even more rarely has any attempt been made to assess the scale of these practices. Recent developments, including the use of large datasets, computational modelling, and high-resolution analytical chemistry, are increasingly offering the means to reconstruct recycling and reuse, and even to approach the thorny matter of quantification. Growing scholarly interest in the topic has also led to an increasing recognition of these practices from those employing more traditional methodological approaches, which are sometimes coupled with innovative archaeological theory. Thanks to these efforts, it has been possible for the first time in this volume to draw together archaeological case studies on the recycling and reuse of a wide range of materials, from papyri and textiles, to amphorae, metals and glass, building materials and statuary. Recycling and reuse occur at a range of site types, and often in contexts which cross-cut material categories, or move from one object category to another. The volume focuses principally on the Roman Imperial and late antique world, over a broad geographical span ranging from Britain to North Africa and the East Mediterranean. Last, but not least, the volume is unique in focusing upon these activities as a part of the status quo, and not just as a response to crisis.


Author(s):  
Allan Matthews ◽  
Adrian Leyland

Over the past twenty years or so, there have been major steps forward both in the understanding of tribological mechanisms and in the development of new coating and treatment techniques to better “engineer” surfaces to achieve reductions in wear and friction. Particularly in the coatings tribology field, improved techniques and theories which enable us to study and understand the mechanisms occurring at the “nano”, “micro” and “macro” scale have allowed considerable progress to be made in (for example) understanding contact mechanisms and the influence of “third bodies” [1–5]. Over the same period, we have seen the emergence of the discipline which we now call “Surface Engineering”, by which, ideally, a bulk material (the ‘substrate’) and a coating are combined in a way that provides a cost-effective performance enhancement of which neither would be capable without the presence of the other. It is probably fair to say that the emergence and recognition of Surface Engineering as a field in its own right has been driven largely by the availability of “plasma”-based coating and treatment processes, which can provide surface properties which were previously unachievable. In particular, plasma-assisted (PA) physical vapour deposition (PVD) techniques, allowing wear-resistant ceramic thin films such as titanium nitride (TiN) to be deposited on a wide range of industrial tooling, gave a step-change in industrial productivity and manufactured product quality, and caught the attention of engineers due to the remarkable cost savings and performance improvements obtained. Subsequently, so-called 2nd- and 3rd-generation ceramic coatings (with multilayered or nanocomposite structures) have recently been developed [6–9], to further extend tool performance — the objective typically being to increase coating hardness further, or extend hardness capabilities to higher temperatures.


Biostatistics ◽  
2019 ◽  
Author(s):  
Dane R Van Domelen ◽  
Emily M Mitchell ◽  
Neil J Perkins ◽  
Enrique F Schisterman ◽  
Amita K Manatunga ◽  
...  

SUMMARYMeasuring a biomarker in pooled samples from multiple cases or controls can lead to cost-effective estimation of a covariate-adjusted odds ratio, particularly for expensive assays. But pooled measurements may be affected by assay-related measurement error (ME) and/or pooling-related processing error (PE), which can induce bias if ignored. Building on recently developed methods for a normal biomarker subject to additive errors, we present two related estimators for a right-skewed biomarker subject to multiplicative errors: one based on logistic regression and the other based on a Gamma discriminant function model. Applied to a reproductive health dataset with a right-skewed cytokine measured in pools of size 1 and 2, both methods suggest no association with spontaneous abortion. The fitted models indicate little ME but fairly severe PE, the latter of which is much too large to ignore. Simulations mimicking these data with a non-unity odds ratio confirm validity of the estimators and illustrate how PE can detract from pooling-related gains in statistical efficiency. These methods address a key issue associated with the homogeneous pools study design and should facilitate valid odds ratio estimation at a lower cost in a wide range of scenarios.


Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2967
Author(s):  
Seunghoon Choi ◽  
Sungjin Park ◽  
Minjoo Park ◽  
Yerin Kim ◽  
Kwang Min Lee ◽  
...  

Biomineralization, a well-known natural phenomenon associated with various microbial species, is being studied to protect and strengthen building materials such as concrete. We characterized Rhodococcus erythreus S26, a novel urease-producing bacterium exhibiting CaCO3-forming activity, and investigated its ability in repairing concrete cracks for the development of environment-friendly sealants. Strain S26 grown in solid medium formed spherical and polygonal CaCO3 crystals. The S26 cells grown in a urea-containing liquid medium caused culture fluid alkalinization and increased CaCO3 levels, indicating that ureolysis was responsible for CaCO3 formation. Urease activity and CaCO3 formation increased with incubation time, reaching a maximum of 2054 U/min/mL and 3.83 g/L, respectively, at day four. The maximum CaCO3 formation was achieved when calcium lactate was used as the calcium source, followed by calcium gluconate. Although cell growth was observed after the induction period at pH 10.5, strain S26 could grow at a wide range of pH 4–10.5, showing its high alkali tolerance. FESEM showed rhombohedral crystals of 20–60 µm in size. EDX analysis indicated the presence of calcium, carbon, and oxygen in the crystals. XRD confirmed these crystals as CaCO3 containing calcite and vaterite. Furthermore, R. erythreus S26 successfully repaired the artificially induced large cracks of 0.4–0.6 mm width.


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