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1 – 10 of over 3000
Article
Publication date: 8 June 2015

N Mahendra Prabhu, K.A. Gopal, S. Murugan, T.K. Haneef, C. K. Mukhopadhyay, S. Venugopal and T. Jayakumar

– The purpose of this paper is to determine the feasibility of identifying the creep rupture of reactor cladding tubes using acoustic emission technique (AET).

Abstract

Purpose

The purpose of this paper is to determine the feasibility of identifying the creep rupture of reactor cladding tubes using acoustic emission technique (AET).

Design/methodology/approach

The creep rupture tests were carried out by pressuring stainless steel capsules upto 6 MPa at room temperature and then heating continuously in a furnace upto rupture. The acoustic emission (AE) signals generated during the creep rupture tests were recorded using a 150 kHz resonant sensor and analysed using AE Win software.

Findings

When rupture occurs in the pressurized capsule tube representing the cladding tube, AE sensor attached to a waveguide captures the mechanical disturbance from the capsule and these data can be advantageously used to identify the creep rupture event of the cladding tube.

Practical implications

The creep rupture data of fuel clad tube is very important in design and for smooth operation of nuclear reactors without fuel pin failure in reactors.

Originality/value

AE is an advanced non-destructive evaluation technique. This technique has been successfully applied for on-line monitoring of creep rupture of the reactor cladding tube which otherwise could be detected by thermocouple readings only.

Details

International Journal of Structural Integrity, vol. 6 no. 3
Type: Research Article
ISSN: 1757-9864

Keywords

Article
Publication date: 1 January 1991

J. Seyyedi, B. Arsenault and J.P. Keller

Quasi shear and tensile mode stress‐rupture and quasi shear mode creep behaviours were investigated for aged production surface mount soldered connections of 127 mm pitch…

Abstract

Quasi shear and tensile mode stress‐rupture and quasi shear mode creep behaviours were investigated for aged production surface mount soldered connections of 127 mm pitch, rigid gullwing and J‐bend configurations at ambient and 60°C (on limited specimens) environments. These joints were manufactured by the vapour phase reflow soldering process using a 63Sn‐37Pb solder composition. Metallographic examinations and fractrographic studies were also performed on appropriate specimens to characterise the metallurgical attributes of the solder and the joint failure. A relatively coarse solder microstructure was observed with both joint configurations. The steady‐state creep data of both soldered joints exhibited two distinct creep regimes. A grain boundary‐controlled regime at low loads with a slope of 042 for gullwing and 0?50 for J‐bend joints was followed by a dislocation climb‐controlled regime at high loads with a slope of 0?13 and 0?24 for gullwing and J‐bend configurations, respectively. The log‐log plot of applied load varied linearly with rupture time for the entire load range for the respective soldered joints for both modes of testing at room temperature. A transgranular fracture morphology was found to predominate for the entire load regime for the quasi shear mode tested gullwing joints. A mixed‐mode fracture morphology with predominantly transgranular features was observed for both low and high loading conditions for quasi shear mode tested J‐bend specimens. The steady‐state creep elongation in shear showed a strong dependence on the applied load for both types of soldered joints. This was primarily attributed to the presence of relatively large creep transients, especially at higher loads.

Details

Soldering & Surface Mount Technology, vol. 3 no. 1
Type: Research Article
ISSN: 0954-0911

Article
Publication date: 1 April 2003

W.J. Plumbridge

With the continued miniaturisation of electronics equipment, a more detailed examination of the mechanical behaviour of solders is required to ensure reliability in…

Abstract

With the continued miniaturisation of electronics equipment, a more detailed examination of the mechanical behaviour of solders is required to ensure reliability in performance. The paper reviews various aspects of the interpretation of the creep response of lead‐containing and lead‐free alloys. It demonstrates the necessity of acquiring stress‐rupture data over as long a period as possible to avoid non‐conservative extrapolation. For example, at 75°C, the transition in slope of the applied stress vs time to rupture plot occurs after about 1,000 h for Sn‐37Pb, although for the lead‐free alloys examined no such transition is observed within this timescale. Sometimes, deformation may be a more appropriate failure criterion than rupture, and it is shown that for Sn‐37Pb this may result in substantially shorter failure times than utilising a rupture criterion. The quality of life estimation methods then depends upon the extent of this stage when the creep rate is a minimum. The Y factor (tm : tr) where tm is the time spent in steady state or within 10 per cent of the minimum creep rate, for all the solders examined at 75°C generally falls into the 20‐30 per cent range. Estimations of creep life may substantially under predict because of this.

Details

Soldering & Surface Mount Technology, vol. 15 no. 1
Type: Research Article
ISSN: 0954-0911

Keywords

Article
Publication date: 1 March 2004

Dwayne D. Tannant and Caigen Wang

Simple discrete element models using PFC2D models with bonded assemblies of particles were used to numerically simulate direct tension and block punching tests on thin…

1600

Abstract

Simple discrete element models using PFC2D models with bonded assemblies of particles were used to numerically simulate direct tension and block punching tests on thin spray‐on tunnel liner materials to gain insight about the liner support mechanisms. PFC2D input parameters were calibrated such that the rupture load and elongation at rupture were similar to the laboratory test data. The calibrated model of the liner material was then used to simulate a liner around a highly stressed tunnel in rock where stresses caused extensive fracturing near the top of the tunnel. The effect of the liner was analysed by modelling the tunnel with and without the liner and showed that the liner had minimal impact on fracture propagation in the rock because of the liner's highly deformable nature. However, the liner was able to retain the fractured rock in place.

Details

Engineering Computations, vol. 21 no. 2/3/4
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 20 March 2009

Mehdi Attarchi, Mahyar Mazloumi, S.K. Sadrnezhaad, A. Jafari and M. Asadi

The purpose of this paper is to evaluate advanced mathematical electrochemical noise analysis (ENA) as a way of corrosion monitoring for carbon steel.

Abstract

Purpose

The purpose of this paper is to evaluate advanced mathematical electrochemical noise analysis (ENA) as a way of corrosion monitoring for carbon steel.

Design/methodology/approach

The electrochemical potential/current noise was recorded simultaneously with a working‐reference‐working electrode set up and the processing of data was performed through fast Fourier transformation (FFT) and wavelet transformation (WT) routes. The formation and rupture of carbonate films on St37 steel electrodes in a 0.5 M sodium bicarbonate electrolyte was studied for 20 h utilizing an electrochemical noise approach.

Findings

Although the slope of mid‐range of noise impedance exhibited a mechanistic style, and increased with film formation and decreased with film rupture, FFT of potential noise was more sensitive to film formation and rupture. WT of potential noise depicted that ν=1.41 × 10−2 Hz was the boundary frequency in the film formation. At frequencies higher than the mentioned limit, the fraction of distributed potential decreased with time. However, the opposite behavior was observed during the rupture of the film.

Originality/value

The preliminary results show that the proposed novel electrochemical method, wavelet and FFT ENA, is very able to monitor the corrosion behavior of carbon steel corrosion in carbonate media.

Details

Anti-Corrosion Methods and Materials, vol. 56 no. 2
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 17 August 2012

Jun Zhang, Zuqiang Liu, Yanjie Liu and Yong Liu

The purpose of this paper is to apply grey statistical model to identify and classify live fault rupture.

131

Abstract

Purpose

The purpose of this paper is to apply grey statistical model to identify and classify live fault rupture.

Design/methodology/approach

Based on grey statistical mode, this paper uses eight faults' ripping speed observation data from 1997 to 2001, according to the grey statistics method for analysis, and recognizes active fault rupture situation. Using the conventional methods, namely taking all faults monitoring stations' average dislocation rate to analysis and make judgment, the average results are obtained.

Findings

The results show that the results are closer to reality because the grey statistical evaluation method has considered dislocation rate and other discrete factors.

Practical implications

The method exposed in the paper can be used to monitor and recognize live fault rupture in earthquake prediction.

Originality/value

According to the fault dislocation rate, this paper advances active fault rupture identification and classification method based on grey statistical model.

Article
Publication date: 1 March 1989

L. Zakraysek

Multilayer printed wiring boards make use of electrodeposited copper from two sources. Copper for conductor traces comes from foil manufacturers through thin laminate…

Abstract

Multilayer printed wiring boards make use of electrodeposited copper from two sources. Copper for conductor traces comes from foil manufacturers through thin laminate suppliers. Copper plating for layer interconnection is performed in an in‐house PTH process. Each source makes use of plating chemicals that are obtained from industry suppliers, but production requirements inherent in foil manufacture or in PTH processing can cause variations that occasionally result in copper deposits that exhibit poor hot strength. In a PWMLB, this can result in corner cracks, barrel cracks and inner layer cracks because some of the copper deposits will be susceptible to fissuring under thermal stress conditions. The phenomenon of hot fissuring is caused by the presence of co‐deposited impurities that degrade the hot strength of the deposit due to easy grain boundary separation at elevated temperatures. Stresses imposed by a solder float test, by soldering or by thermal cycling are then sufficient to cause microcracking in a copper plate that is in this condition. In this paper, the author describes how changes in the quality of copper plate can be monitored with a hot rupture mechanical test method. By testing plated copper samples before board fabrication, it is possible to detect and evaluate harmful effects such as fissuring before the electroplated copper is used in a PWMLB assembly.

Details

Circuit World, vol. 15 no. 4
Type: Research Article
ISSN: 0305-6120

Article
Publication date: 10 February 2021

Mohamed Seddik Hellas, Chaib Rachid and Ion Verzea

Liquefied petroleum gas (LPG), known by its ecological qualities, making Algeria has since the 1980s carried out a policy of development of LPG fuel in substitution of…

Abstract

Purpose

Liquefied petroleum gas (LPG), known by its ecological qualities, making Algeria has since the 1980s carried out a policy of development of LPG fuel in substitution of traditional fuels and especially petrol. However, following a series of accidents (fires, explosions, etc). that occurred in 1999, 20 years after the introduction of the LPG in France these incidents led to the search for the strengthening of the safety of the installations by better or new technical and/or organizational measures. This strategy consists in establishing a balance between environmental protection and economic profitability while ensuring the safety aspect.

Design/methodology/approach

The approach used is quantitative risk analysis authors have identified the potential accident scenarios that consist of leakage and rupture of tanks depend on bow tie. According to the latter using PHAST software, to model these scenarios (thermal, overpressure and dispersion) and their effects on human beings and goods.

Findings

In this paper, it was noted that there are scenarios such as (jet fire, dispersion), are affected by atmospheric conditions (wind speed humidity), the stronger the wind, the higher the LPG spread unlike instant scenarios (1.3 s for the fireball and millisecond for the explosion) that have not been related to climatic conditions because they have a short duration on the one hand, and on the other hand, a safe distance is given in each phenomenon. Finally, some instructions for drivers and installers have been identified by protective and preventive action.

Originality/value

Based on a quantitative risk analysis, this work involves modelling potential accident scenarios such as (fireball, jet fire, flash fire and explosion) in the event of a gas leak and rupture in the tank. It aims to sensitize drivers and LPG kit installers, even to get a clear view on these accidental phenomena and how to avoid them.

Details

World Journal of Engineering, vol. 18 no. 3
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 1 January 2006

Judy Pate

The purpose of this paper is to propose a processual framework of psychological contract breach, which maps holistically the interactions among concepts drawn from the…

3984

Abstract

Purpose

The purpose of this paper is to propose a processual framework of psychological contract breach, which maps holistically the interactions among concepts drawn from the trust and justice literature. However, the price of a holistic picture is frequently a lack of depth of analysis of any single variable, and consequently the second part of the paper seeks to unpack a central variable, circumstances of breach.

Design/ methodological approach

Draws on findings from a four‐year qualitative study and investigates the psychological contract in situ. The issue of circumstances of breach was explored inductively by applying in‐depth employee case histories using theory‐based sampling.

Findings

Key findings indicate that breach may occur as a result of direct or indirect organisational actions. Further the degree of reaction may differ according to the type of trigger (i.e. a distributive, procedural or interactional justice issue) and also the extent to which the organisation is held responsible.

Research limitations/Implications

Based on an in‐depth study of one organisation over time; further research is required to ascertain the generalisability of the key findings.

Practical implications

The implications for the practice of management surround the issue of unanticipated results of actions. Changes to substantive, distributive justice issues are likely to result in psychological contract violation or rupture unless handled with care. The repercussions of relationship fracture include diminished employees attitude and, perhaps more importantly for the organisation, negative behaviour.

Originality/value

The key contribution of the paper is that it presents a new model of psychological contract and elucidates a key aspect of the holistic model using empirical data.

Details

Journal of European Industrial Training, vol. 30 no. 1
Type: Research Article
ISSN: 0309-0590

Keywords

Article
Publication date: 26 April 2018

Vania Silva Carvalho and Ana Carolina Conti-Silva

This paper aims to examine the bioactive compounds and texture properties of cereal bars formulated with banana peel flour during storage.

Abstract

Purpose

This paper aims to examine the bioactive compounds and texture properties of cereal bars formulated with banana peel flour during storage.

Design/methodology/approach

Seven cereal bars were produced and stored during 11 months, under vacuum and protected from the light. The total phenolic compounds, the activity antioxidant by ABTS [2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)] method, the DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) method expressed as EC50 (concentration required to reduce the original amount of free radicals by 50 per cent) and texture properties were evaluated over the storage period.

Findings

In general, total phenolic compounds decreased during storage (from 4.19 to 1.11 mg GAE. g-1f.w.). Although the total antioxidant activity (ABTS method) increased during the fifth month, it reduced during storage (from 3.41 to 0.30 µmol TE.g-1f.w.); and the EC50 was not modified in many formulations, though it decreased in other formulations during storage period (from 3913 to 19221 g fruit.g-1 DPPH). The force of rupture began to increase in the fourth month (reaching 62.4 N), and hardness began to increase in the ninth month (reaching 444 N). The formulation and time factors influenced the total phenolic compounds, total antioxidant activity (ABTS method), force of rupture and hardness, while EC50 was only influenced by the formulation (p-value = 0.001). A principal component analysis showed that time had little effect on the most important characteristics considered in description of the cereal bars.

Originality/value

Cereal bars can be consumed up to the third month of storage, considering the texture of the products. Moreover, the presence of bioactive compounds in cereal bars depends on the addition of banana peel flour, which it contributes to the insertion of total phenolic compounds and total antioxidant activity in cereal bars, aggregating functional properties in these products.

Details

Nutrition & Food Science, vol. 48 no. 3
Type: Research Article
ISSN: 0034-6659

Keywords

1 – 10 of over 3000