Regularities of Changes in the Mechanical Characteristics and Electrical Properties of the Reaction Furnaces Coils Material during Operation

2020 ◽  
Vol 992 ◽  
pp. 706-711
Author(s):  
E.A. Naumkin ◽  
J.N. Shermatov
Keyword(s):  
Structural Changes ◽  
Mechanical Characteristics ◽  
Diffusion Processes ◽  
Relative Magnitude ◽  
Electrical Signal ◽  
Destructive Testing ◽  
Static Tests ◽  
Negative Effect ◽  
Void Structure ◽  
Reaction Furnace

The main causes of early failure of reaction furnaces coils are diffusion processes in the material as a result of which structural changes occur, new phases are formed and void structure is formed in the surface layers of the metal, which has a negative effect on the mechanical characteristics. In this regard as a structurally sensitive method, which allows evaluating the changes occurring in the metal, the response parameters of the electrical signal are used which are sensitive to pore formation and allow predicting the zone of formation of the breaking crack. Fragments of the coils of the reaction furnaces from the radiant section, which were in operation for 750, 1300, 8000, and 10000 hours and the pipe element in the delivery condition were chosen as the objects of the study. As a result of the research a correlation between the amplitude of the first harmonic of the electrical signal output voltage with the results of static tests for tensile and impact bending was established. This happens due to the fact that during operation there is an increase in the relative impact viscosity and relative tensile strength, and the relative magnitude of the voltage amplitude of the first harmonic of the output electrical signal also increases. These results can be used as a method of mechanical properties assessment by non-destructive testing, and also they can be used to develop a criterion for the rejection of reaction furnace coils.

scholarly journals APPROBATION AND ANALYSIS OF EXPERIMENTAL RESEARCHES'S RESULTS OF THE EXTENDED METHOD OF PHYSICAL-MECHANICAL CHARACTERISTICS STEELS'S CONTROL

2018 ◽  
pp. 37-49
Author(s):  
N. I. Chaban ◽  
I. V. Rybitskyi ◽  
M. O. Karpash ◽  
V. D. Myndiuk
Keyword(s):  
Structural Changes ◽  
Mechanical Characteristics ◽  
Oil And Gas ◽  
Experimental Studies ◽  
Calculation Model ◽  
Flaw Detector ◽  
Structural Noise ◽  
Destructive Testing ◽  
Reasonable Choice ◽  
Non Destructive

Most of the oil and gas equipment complex is subjected to cyclic-variable, mechanical, thermal loads and corrosive-active environment. These effects causing a change in the structural statr of the metal contribute to the accelerated development of defects, especially in places with stress concentrators, which ultimately lead to the constructions destruction. Available ultrasonic, electromagnetic, and eddy-current non-destructive testing methods are currently aimed at solving defect detection problems. However, it is more important to timely identify the initial stage of the process of damage accumulation in a metal by determining changes in the structural state of the metal. The article proposes a methodology for studies of steel structural changes arising in the process of exploitation and their impact on mechanical characteristics. A reasonable choice of the optimal indicator characterizing the image of the acoustic structural noise of the material obtained by applying ultrasonic flaw detector in a complete set with piezoelectric converters with a phased array is substantiated. The complex of physical and mechanical parameters of the investigated samples are measured and the results obtained were analyzed. The modern methods of determination of mechanical characteristics of steels are considered, their deficiencies are determined and the methods of their optimization are proposed. The regression-correlation analysis of the experimental studies results was carried out, which resulted in the equation of dependence between a set of non-destructive control parameters and mechanical characteristics of steels was obtained. In order to verify the adequacy of the proposed model and to establish the possibility of controlling the casing and tubing on the samples made, series of experimental studies were carried out, which confirmed the reliability of the resulting calculation model for determining the mechanical characteristics of the steels by using two informative parameters, namely hardness and integral density of images of acoustic structural noise.

The Development and the Study of the Properties of Hydrosorption Material Based on a Blended Thermoplastic Vulcanisate

2017 ◽  
Vol 44 (8) ◽  
pp. 9-14
Author(s):  
M.F. Galikhanov ◽  
D.M. Akhmedzyanova ◽  
N.R. Nikitin
Keyword(s):  
Diffusion Processes ◽  
Testing Machine ◽  
Strength Properties ◽  
Water Soluble ◽  
Butadiene Rubber ◽  
Tensile Testing Machine ◽  
Water Soluble Polymer ◽  
Electret State ◽  
Swelling Rate ◽  
Negative Effect

Hydrosorption thermoplastic vulcanisates (TPVs) with a controllable swelling rate have been developed. They contain low-density polyethylene (LDPE), nitrile butadiene rubber (NBR), and sodium carboxymethyl cellulose (Na-CMC) – a water-soluble polymer (WSP). They were mixed on a laboratory mill in two stages and vulcanised at a temperature of 170°C. At the first stage, the NBR with a vulcanising system and carbon black were mixed with the WSP at 50°C, and at the second stage this composite was mixed with the polyethylene (PE) at 140°C. The hydrosorption, deformation and strength, and electret properties of the obtained TPVs were studied. The study of the sorption properties under conditions of limited and unlimited access of water showed that composites consisting of 25% polyethylene and 75% WSP swell in water by ∼28%, and here processes of migration of the WSP out of the composites are absent. The deformation and strength properties were determined on an Inspekt Mini TR-3 kN tensile testing machine. The level of deformation and strength characteristics of the obtained TPVs is not high, which is due to the low adhesion between the PE and the polar NBR, and also between the NBR and the WSP. However, for seals and gaskets, the achievable level of strength properties is quite adequate. An electret state of the TPVs was obtained in a negative corona discharge as they cooled down after heating to 90°C. Washers were manufactured from the developed TPVs, and they were tested for their sealing capacity. It was shown that the electret state inhibits the process of swelling of the TPVs in water, which is due to the negative effect of the electric field on the rate at which wetting, dissolution, and diffusion processes take place. However, during service, the electret state of articles manufactured from the developed TPVs rapidly relaxes, after which the swelling process occurs at a steady rate. This makes it possible to carry out assembly work involving the fitting or replacement of seals made of the hydrosorption TPVs.

Trends in tourism under economic uncertainty

2020 ◽  
pp. 135481662090960 ◽  
Author(s):  
Khalid Khan ◽  
Chi-Wei Su ◽  
Yi-Dong Xiao ◽  
Haotian Zhu ◽  
Xiaoyan Zhang
Keyword(s):  
Gravity Model ◽  
Structural Changes ◽  
Exchange Rate Regime ◽  
Causal Link ◽  
Policy Uncertainty ◽  
Time Varying ◽  
The United Kingdom ◽  
Window Technique ◽  
Rolling Window ◽  
Negative Effect

We use the gravity model to examine the causal link between economic policy uncertainty (EPU) and inbound tourism (ITM) in the United Kingdom. The results for the full sample demonstrate that EPU Granger causes ITM. This finding shows that association is misappropriated due to structural changes. We apply the time-varying rolling window technique to revisit the dynamic association between EPU and ITM. The findings for the subsamples indicate that EPU has a negative effect on ITM. In contrast, ITM has a positive effect on EPU in the subsamples. These results support the gravity model, which states that as EPU increases, the level of ITM decreases. The results have noteworthy implications for policymakers in the form of consistency in policies and short-term shock forecasting that is capable of greater shock-absorbing capacity to lessen the revocation of tourist programs. A stable exchange rate regime in the destination country will make tourism cheaper and more attractive to tourists. Decision-makers should consider time-varying attributes to establish tourism activities for effective and accurate predictions.

Characterization of Anisotropic and Irregularly-Shaped Materials by High-Sensitive Thermal Conductivity Measurements

2007 ◽  
Vol 124-126 ◽  
pp. 1641-1644 ◽  
Author(s):  
M. Gustavsson ◽  
Hideaki Nagai ◽  
Takeshi Okutani
Keyword(s):  
Thermal Conductivity ◽  
Structural Changes ◽  
Bulk Material ◽  
Thermal Contact ◽  
Measurement Techniques ◽  
High Sensitivity ◽  
Conductivity Measurements ◽  
Destructive Testing ◽  
Analysis And Design ◽  
Wide Range

In modern thermal analysis and design involving thermal transport in solid components it is necessary to apply different modeling of the thermal heat flow in bulk material and across solid surface interfaces either in shape of a layer or a solid-solid interface. Similar differences occur when applying different measurement techniques. Some techniques have been developed specifically for the purpose of performing measurements of bulk properties by removing the influence from thermal contact resistance between the measurement probe and the sample material. Thermal conductivity measurements on metal and ceramic objects of various geometries such as thin bars, thin sheets as well as coatings or layers are here described when using the Transient Plane Source technique. A summary overview of the recent developments of this technique, including its ability to be applied in measurement situations covering a wide range of length and time scales, is also presented. Structural changes in anisotropy can be recorded with high sensitivity by comparative measurements. The technique may be applied in situations requiring non-destructive testing, e.g. samples of particular geometry used for mechanical or tensile testing.

Experimental Study on Mechanical Characteristics of Knitted-Dapped Metal Rubber

2013 ◽  
Vol 820 ◽  
pp. 67-70
Author(s):  
Tuo Li ◽  
Hong Bai Bai ◽  
Chun Hong Lu
Keyword(s):  
Experimental Study ◽  
Dynamic Characteristics ◽  
Mechanical Characteristics ◽  
Dynamic Tests ◽  
Static Stiffness ◽  
Static Tests ◽  
Metal Rubber ◽  
Low Stiffness

Knitted-dapped metal rubber was developed to solve problems of metal rubber with low stiffness and test samples with different sizes were manufactured. Static tests and dynamic tests were carried out to study influences of density and thickness on the static stiffness and influences of frequency, amplitude and preload on dynamic characteristics. Results show that static stiffness rises when density or thickness increases. Frequency has little influence on dynamic characteristics. Knitted-dapped metal rubber will have smaller stiffness and better characteristics of damping, if amplitude increases; if preload increases, energy consumed in the vibration will be more.

Measurement of Lateral Dopant Diffusion in Rapid Thermal Annealed W-Polycide Gate Structures

1996 ◽  
Vol 429 ◽  
Author(s):  
T. Schiml ◽  
J. Bevk ◽  
M. Furtsch ◽  
G. E. Georgiou ◽  
R. Cirelli ◽  
...  
Keyword(s):  
Process Optimization ◽  
Structural Changes ◽  
Diffusion Processes ◽  
Vertical Resolution ◽  
Dopant Diffusion ◽  
Dopant Distribution ◽  
Dopant Activation ◽  
Layer Structures ◽  
Dual Gate ◽  
Sims Analysis

AbstractLateral dopant diffusion is a well known problem in dual-gate W-polycide CMOS devices. We have recently demonstrated that RTA processing helps to alleviate this problem and at the same time ensures sufficient dopant activation. However, due to the complex micro-structural changes in both poly-Si and WSix (x˜2.5) layers during the RTA process, the time dependence of the diffusion processes and dopant distribution are difficult to predict. Consequently, the process optimization and device simulations are rather unreliable. We describe a new experimental technique to measure lateral dopant diffusion and 2-dimensional dopant distribution in RTA processed W-polycide structures using conventional SIMS analysis of lithographically defined test structures. Our experiments show that the technique is capable of measuring lateral dopant diffusion over distances between one and tens of microns without losing the vertical resolution of conventional SIMS profiling. The technique can be used to study diffusion processes in a variety of materials and multi-layer structures.

Quality Assurance of Laser Welded Axisymmetric Sandwich Structure

2013 ◽  
Vol 549 ◽  
pp. 529-534 ◽  
Author(s):  
Kimmo Illikainen ◽  
Kalle Holappa ◽  
Kari Mäntyjärvi
Keyword(s):  
Quality Assurance ◽  
Working Conditions ◽  
Sandwich Structure ◽  
Visual Inspection ◽  
Experimental Tests ◽  
The Body ◽  
Destructive Testing ◽  
Great Strength ◽  
Static Tests

This study focuses on quality assurance in a laser welded axisymmetric sandwich structure that functions as the body of an electric machine. The manufacturing quality of the structure was measured using destructive testing and visual inspection. The destructive tests included both fatigue and static tests in addition to a macrographic examination. The visual inspection comprised ocular estimates of the laser welded seams as well as their requirements. Compared with the real working conditions of the machine, the experimental tests were exhaustive. Nevertheless, in the tests, the bodies held up very well which shows the great strength of the structure.

scholarly journals STRUCTURAL INVESTIGATION OF THE INTERMEDIATE LAYER IN A BIMETAL MILL ROLLER PRODUCED BY THE METHOD OF VERTICAL AXIS CENTRIFUGAL CASTING

2021 ◽  
Vol 1 ◽  
pp. 255-258
Author(s):  
Angel Velikov ◽  
Ivanov Ivanov ◽  
Ivan Georgiev
Keyword(s):  
Cast Iron ◽  
Structural Changes ◽  
Structural Investigation ◽  
Diffusion Processes ◽  
Centrifugal Casting ◽  
Vertical Axis ◽  
Ductile Cast Iron ◽  
High Chromium ◽  
Supporting Layer ◽  
Mill Roller

Subject of the investigation is a bimetallic mill roller with external, working layer from high chromium material and inner, supporting layer from ductile cast iron. The processes, accompanying the formation of a transition layer in bimetallic castings, produced by centrifugal casting have been investigated. Attention has paid to the structural changes in the transition zone, caused by the diffusion processes occurring during the casting and crystallization.

scholarly journals THE ANALYSIS OF METHODOLOGIES FOR TESTING COMPRESSIVE STRENGTH IN MASONRY MORTAR JOINTS / MŪRO SKIEDINIO GULSČIOJOJE SIŪLĖJE GNIUŽDOMOJO STIPRIO TYRIMŲ METODŲ ANALIZĖ

2014 ◽  
Vol 6 (5) ◽  
pp. 514-519 ◽  
Author(s):  
Tomas Šlivinskas
Keyword(s):  
Compressive Strength ◽  
Mechanical Characteristics ◽  
Ultrasonic Waves ◽  
Non Destructive Testing ◽  
Testing Methods ◽  
Destructive Testing ◽  
Advantages And Disadvantages ◽  
Mortar Strength ◽  
Non Destructive ◽  
Masonry Mortar

The article analyzes masonry as composite material and presents the factors that affect the mechanical characteristics of masonry. The article also deals with the most frequently used destructive and non-destructive testing methods for the compressive strength of masonry mortar as well as related advantages and disadvantages. Moreover, the analysis of methods for testing ultrasonic waves has been carried out. The article reveals that for using the methodology of testing a mortar bonded wafer, the compressive strength correlation of masonry mortar is set between the ascertainment of masonry mortar strength using a regular mortar testing methodology (LST EN 1015-11:2004) and the compressive strength of mortar possibly taken from masonry joints. The obtained results of an experimental study on the samples have demonstrated that the strength reduction ratio of masonry mortar depends on the compressive strength of mortar. The value of the ratio is increasing with the descending compressive strength of mortar. Šiame straipsnyje nagrinėjamas mūras kaip kompozitinė medžiaga. Apžvelgiami veiksniai, veikiantys mechanines mūro charakteristikas. Išnagrinėti dažniausiai taikomi mūro skiedinio gniuždomojo stiprio tyrimų metodai, pateikti metodų privalumai ir trūkumai. Straipsnyje, taikant klijuotų skiedinio plokštelių bandymo metodiką, nustatyta mūro skiedinio gniuždomojo stiprio priklausomybė tarp mūro skiedinio stiprio nustatymo pagal įprastinę skiedinio bandymo metodiką ir skiedinio, tikėtina, paimto iš mūro siūlės, gniuždomojo stiprio.

Force deficit during the onset of muscle hypertrophy

1989 ◽  
Vol 67 (6) ◽  
pp. 2600-2607 ◽  
Author(s):  
S. C. Kandarian ◽  
T. P. White
Keyword(s):  
Muscle Mass ◽  
Protein Concentration ◽  
Muscle Hypertrophy ◽  
Structural Changes ◽  
Relative Magnitude ◽  
Interstitial Space ◽  
Cross Sectional Area ◽  
Specific Force ◽  
Sectional Area ◽  
Cross Sectional

The purpose was to study selected structural changes associated with the deficit in maximum specific force (N/cm2) during the early development of skeletal muscle hypertrophy. Ablation of gastrocnemius and plantaris muscles was performed bilaterally in 35-day-old rats (n = 41), and the soleus muscle was studied from days 1 to 30 thereafter. Compared with control muscles from age-matched unoperated rats (n = 48), muscle mass and cross-sectional area increased in parallel from 28 to 52% over the 30-day postoperative period. Specific force of hypertrophied muscle was depressed 38% at days 1 and 3, and by 28% from days 5 to 30 after synergistic muscle ablation compared with age-matched control values. Interstitial space was 38% greater than the control value of 20.4 +/- 1 microliters/100 mg at day 1 only. Protein concentration was depressed 15% for 7 days after the ablation operation, and connective tissue protein concentration was unchanged. The relative magnitude of increased mean fiber cross-sectional area was less than that of muscle mass until day 7 after ablation. Mononuclear cell infiltration in interfascicular spaces occurred from days 3 to 30 without light microscopic evidence of muscle fiber injury. Initial functional deficits are explained in part by an enlarged interstitial space and decreased protein concentration; later deficits are likely accounted for by intracellular changes.

Sign in / Sign up

Export Citation Format

Share Document