Experimental device design justification for radiation resistance tests of single-mode optical fibers and FBG-based sensors at the IVG.1M reactor

One of the most important stages in the development of an experimental device is to carry out a series of computational studies to substantiate the compliance of device design with the objectives of the experiment, such as the choice of test modes and the study of standard and hypothetical emergency modes of its operation. Result of these studies is the neutron-physical, thermal, strength and hydrodynamic characteristics of the structural elements of the device and working bodies. During this work, a series of neutron calculations was conducted using the MCNP6 code and thermal-physical calculations using the ANSYS software package of two configurations of the experimental device. A feature of the calculated studies is the presence of specific requirements for the thermal state of the experimental device sleeve. Namely, ensuring a predetermined temperature gradient between its ribs, which should not exceed 4°K during the reactor tests.

Computational and Experimental Method for Assessing the Thermal Strength of High-Loaded Diesel Engines

The article discusses the reasons of fatigue failure of pistons of high-loaded diesel engines. A deformation-kinetic criterion is proposed, generalized to non-isothermal loading, which allows more correct calculation of the number of thermal loading cycles before the appearance of fatigue damage. For a specific implementation of the proposed criterion, a calculated assessment of the piston stress-strain rate was carried out using the FEM. The boundary conditions for the calculation were obtained by thermometry of the piston head on a non-motorized thermal stand (TS). Comparison of the calculated and experimental values of the number of thermal cycles before the appearance of cracks on the edge of the combustion chamber (CC) of pistons made by casting and isothermal stamping is given.

Post-thermal properties of Portland cement concrete made with copper slag as fine aggregates

Purpose The purpose of this paper is to investigate the effect of elevated temperature on mechanical and physical properties of concrete specimens obtained by substituting the river sand with copper slag (CS) at proportions of 25%, 50%, 75% and 100%. The specimens were heated in an electric furnace up to 100, 200, 300, 400, 500 and 600 C and kept at these temperatures for 2 h duration. After the specimens were cooled in the furnace, mass loss, ultrasonic pulse velocity (UPV), compressive strength, split tensile strength (STS), flexural strength (FS) and modulus of elasticity (MOE) values were determined. No spalling occurred in the specimens after subjected to elevated temperature. The surface cracks were observed only in specimens exposed to 600 C. The maximum reduction in compressive strength and STS at 600C is 50.3% and 36.39% for referral mix (NC), 18% and 16% for specimens with 100% CS (MCS4). The reduction in MOE of specimens is observed to be high as copper slag content increases with increasing temperature. Scanning electron microscopy (SEM) studies are carried out to examine the changes in micro-structures of specimens after exposed to elevated temperatures. Design/methodology/approach After casting of concrete specimens, it is cured for 28 days. After attainment of 28 days age, the concrete specimens is taken out from the curing tank and allowed to dry for 2 days to remove any moisture content in the specimens to prevent explosive spalling during the time of heating. The prepared concrete specimen is subjected to temperatures of 100°C, 200°C, 300°C, 400°C, 500°C and 600°C up to 2 h duration. The physical test, mechanical test and SEM studies are carried out after cooling of specimens to room temperature (RT). The quality of concrete specimens is measured by conducting UPV test after cooling to RT. Findings The post-thermal strength properties of concrete specimens with copper slag contents are higher than referral mix concrete. The reduction of MOE of concrete specimens is more with incremental in copper slag content with increase in temperatures. Furthermore, the quality of concrete specimens is ranging from “good to medium” up to 500C temperatures based on UPV test. Originality/value In this research work, the natural sand is fully replaced with copper slag materials in the concrete mixes. The post-thermal strength properties like residual compressive strength, residual STS, residual FS and residual MOE is higher than referral mix after subjected to elevated temperature conditions. Higher density and toughness properties of copper slag materials will contribute to concrete strength. The effect of elevated temperature is more on MOE of concrete specimens having higher copper slag contents when comparing to specimens compressive strength.

Kinetics and mechanisms of coke and sinter on the coupling reaction to evaluate the integrated effects of coke solution loss reaction on blast furnace processes

The gas–solid coupling reaction kinetics at a constant temperature at each temperature point in the high-temperature cohesive zone in a blast furnace environment were simulated using industrial blast furnace raw material sinter, the low-reactivity conventional coke, and the high-reactivity unconventional coke. In this method, the coupling test of the sinter and coke at constant temperature was performed after a supporting thermogravimetric device was used to carry out pre-reduction, and the coupling reaction of industrial-grade sinter and coke were used to obtain the kinetic data and a mathematical description of the reaction mechanism. The results showed that in the high-temperature cohesive zone, the gasification reaction rate of the low-reactivity coke is the rate-controlling step of the gas–solid coupling reaction rate between the sinter and the conventional low-reactivity coke. By contrast, the rate-controlling step of the gas–solid coupling reaction rate between the sinter and highly-reactive coke is the reduction of sinter. The maximum difference between the initial reaction temperatures of the two kinds of coke samples is 30 °C. Using the same testing standard as coke strength after the reaction (CSR) to test the thermal strength of coke after the coupling reaction, it was found that there is little difference between the thermal strengths (CSRp) of the two kinds of coke after the reaction. The thermal strength of the high-reactivity coke is the worst at 1100 °C, and that of coke with low reactivity is the worst at 1200 °C. The highly reactive coke can operate smoothly in the blast furnace of the cohesive zone and this is explained from the perspective of kinetics. This knowledge provides guidance for the evaluation of the capability of coke to resist solution loss.

Thermal strength of retention compartment interacting with exhaust gas

The thermal strength of the retention compartment is calculated to analyze the possibility of multiple use for a rocket start. The transient heat field of the retention compartment, which is induced by the interaction of the exhaust gas with the retention compartment, is analyzed. The part of the retention compartment undergoes significant heat action with a high-temperature gradient when the rocket is started. This heat action essentially changes in time. This leads to the generation of significant transient stress fields. The aim of the present paper is the calculation of the maximal values of stresses induced by the heat field. We analyze the stress state induced by the steady-state heat field. This field corresponds to the transient heat field at the time when the maximal temperature gradient is observed. The upper bound of stresses in the retention compartment is obtained by the suggested method.

A NEW METHOD FPR ASSESSING THE RESISTANCE OF A REINFORCED CONCRETE COLUMN WITH A CIRCULAR CROSS SECTION

The developed method for assessing fi re resistance relates to the fi eld of fi re safety of buildings and structures and can be used to classify a reinforced concrete column of circular cross-section according to fi re resistance indicators. The essence of the proposed solution is to assess the design limit of fi re resistance of a reinforced concrete column of circular cross-section for the loss of bearing capacity under fi re conditions according to a set of single quality indicators without direct testing. The description of the process of resistance of a reinforced concrete column to fi re impact is presented by a mathematical relationship that takes into account the dimensions of the cross-section of the column, the degree of reinforcement, the intensity of force stresses, the normative strength of concrete to the resistance to axial compression and the rate of thermal diff usion of concrete. To determine the fi re resistance limit of a reinforced concrete column with a circular cross-section, an analytical expression that combines all the described indicators is proposed. The proposed method for determining fi re resistance refers to a thermal strength problem, which makes it possible to determine the fi re resistance of a reinforced concrete column of circular cross-section without full-scale fi re exposure, and reduces economic costs.

Basics of computer engineering surface layer of polished ceramics

The basic principles of computer engineering of the surface layer of polished ceramics are given. They are based on two calculation schemes, a mathematical model, algorithms for solving problems of stationary and unsteady thermoelasticity, an automated system of thermal strength calculations and a method for calculating horizontal and vertical displacements, temperature, stresses and stress intensity using the control point method.