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21 – 30 of over 130000Arunangshu Mukhopadhyay, Subrata Ghosh and Somes Bhaumik
This paper seeks to report an experimental investigation on the tearing and tensile strength behaviour of military khaki fabrics from grey to finished process.
Abstract
Purpose
This paper seeks to report an experimental investigation on the tearing and tensile strength behaviour of military khaki fabrics from grey to finished process.
Design/methodology/approach
Uses three different types of military fabric (3 up 1 down twill), differing in type of constituent yarns (ring/rotor) in order to test their tearing and testing strength behaviour.
Findings
Tearing strength of fabric is found to be very much susceptible to change due to the process variation, while fabric tensile strength is relatively less sensitive. Ring spun yarn fabric shows higher tearing strength compared with rotor spun yarn fabric. However, the difference in their tearing strength reduces substantially as the process approaches towards the finished state. On the other hand, rotor spun yarn fabric exhibits higher tensile strength along the warp. Tearing strength along bias direction is in between warp and weft wise tearing strength; whereas tensile strength is lowest while tested along the bias direction. During the grey to finished process, tear strength falls at bleaching and dyeing, and particularly drops in strength is being more at the dyeing stage.
Originality/value
This study has investigated the tearing and tensile strength behaviour of military khaki fabrics from grey to finished state, developing understanding of the impact of different processes on the tearing strength, so that fabric of the required tear strength can be developed with process modification.
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S. Ghanbarpour, H. Mazaheripour, S.H. Mirmoradi and A. Barari
Self‐compacting concrete (SCC) offers several economic and technical benefits; the use of steel fibers extends its possibilities. Steel fibers bridge cracks, retard their…
Abstract
Purpose
Self‐compacting concrete (SCC) offers several economic and technical benefits; the use of steel fibers extends its possibilities. Steel fibers bridge cracks, retard their propagation, and improve several characteristics and properties of the SCC. The purpose of this paper is to investigate the effects of type and volume fraction of steel fiber on the compressive strength, split tensile strength, flexural strength and modulus of elasticity of steel fiber reinforced self‐compacting concrete (SFRSCC).
Design/methodology/approach
For this purpose, Micro wire and Wave type steel fibers with l/d ratios of 50 were used. Three different fiber volumes were added to concrete mixes at 0.5, 0.75 and 1 per cent by volume of SCC. Six different SFRSCC mixes were prepared. After 28 days of curing, compressive, split and flexural strength and modulus of elasticity were determined.
Findings
It was found that, inclusion of steel fibers significantly affect the split tensile and flexural strength of SCC accordance with type and vf. Besides, mathematical expressions were developed to estimate the flexural, modulus of elasticity and split tensile strength of SFRSCCs regarding of compressive strength.
Originality/value
It was found that inclusion of steel fibers significantly affected the split tensile and flexural strength of SCC accordance with type and f v.
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Hakan Keskin, Musa Atar, Süleyman Korkut and Derya Sevim Korkut
The purpose of this paper is to determine the effect of Imersol Aqua impregnation of Scotch pine, Oriental spruce, and Uludağ fir on the surface adhesion strength of various types…
Abstract
Purpose
The purpose of this paper is to determine the effect of Imersol Aqua impregnation of Scotch pine, Oriental spruce, and Uludağ fir on the surface adhesion strength of various types of varnishes. The finding obtained would benefit the manufacturers of building materials and furniture, where the surface adhesion strength of water‐based varnishes is a concern.
Design/methodology/approach
For this purpose, test samples were prepared from Scotch pine, Oriental spruce, and Uludağ fir woods that met the requirements of ASTM D 358. The samples were impregnated with Imersol Aqua using short‐, medium‐, and long‐term immersion techniques according to ASTM D 1413 and the manufacturer's instructions. After impregnation, surfaces were coated with synthetic, acrylic, polyurethane, and water‐based varnishes in accordance with ASTM D 3023 standards. After the varnishing process, the adhesion strength of the samples was determined in accordance with ASTM D 4541.
Findings
It was also found that among the wood samples, the adhesion strength was highest in Scotch pine and lowest in Uludağ fir. The synthetic varnish produced the highest adhesion strength, whereas polyurethane and acrylic varnishes had the lowest adhesion strength. The adhesion strength was highest after medium‐term immersion and lowest after long‐term dipping. The highest adhesion strength (4.299 MPa) was produced by a combination of Scotch pine, medium‐duration immersion, and the use of a wood‐based varnish. The lowest adhesion strength (2.090 MPa) resulted from the combination of Uludağ fir, long‐term immersion, and a water‐based varnish.
Research limitations/implications
Impregnating woods using materials with appropriate water repellent, biotic, and abiotic effects before the application of varnishes and paints is important for long‐term protection against photochemical degradation, dimensional changes, biological factors, and fire.
Practical implications
The effect of a varnish on surface adhesion strength can determine the usefulness of the varnish.
Originality/value
Improving surface adhesion of some varnishes via medium‐term impregnation with Imersol Aqua impregnation should be used on Scotch pine, Oriental spruce, and Uludağ fir woods which could be used in the manufacturing of building materials and furniture, where the surface adhesion strength of water‐based varnishes is a concern.
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Hassan A.M. Mhamoud and Jia Yanmin
This study aims to focus on the resistance to elevated temperatures of up to 700ºC of high-performance concrete (HPC) compared to ordinary Portland concrete (OPC) with regards to…
Abstract
Purpose
This study aims to focus on the resistance to elevated temperatures of up to 700ºC of high-performance concrete (HPC) compared to ordinary Portland concrete (OPC) with regards to mass loss and residual compressive and flexural strength.
Design/methodology/approach
Two mixtures were developed to test. The first mixture, OPC, was used as the control, and the second mixture was HPC. After 28 days under water (per Chinese standard), the samples were tested for compressive strength and residual strength.
Findings
The test results showed that at elevated temperatures of up to 500ºC, each mixture experienced mass loss. Below this temperature, the strength and the mass loss did not differ greatly.
Originality/value
When adding a 10 per cent silica fume, 25 per cent fly, 25 per cent slag to HPC, the compressive strength increased by 17 per cent and enhanced the residual compressive strength. A sharp decrease was observed in the residual flexural strength of HPC when compared to OPC after exposure to temperatures of 700ºC.
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Hamed Hemmati Pourghashti, Malek Mohammad Ranjbar and Rahmat Madandoust
The purpose of this paper is to conduct a laboratory investigation on measuring the tensile strength of recycled concrete using a double punch test. Furthermore, one of the main…
Abstract
Purpose
The purpose of this paper is to conduct a laboratory investigation on measuring the tensile strength of recycled concrete using a double punch test. Furthermore, one of the main goals of this study is to compare the tensile and compressive strengths of recycled concrete samples.
Design/methodology/approach
Recycled concrete samples were made with variables such as aggregate type (natural stone and aggregate recycled concrete), different water-to-cement ratios and different treatment conditions in the first stage. In the next stage, the double punch test was performed on them, and finally the results obtained from experiments were analyzed and investigated.
Findings
According to the above tests, it was concluded that: first, according to the laboratory results, the strength of concrete containing recycled aggregates becomes closer to the strength of concrete containing natural aggregates whenever the water-to-cement ratio is higher. Second, upon investigating the treatment conditions, it was observed that the treatment had a greater effect on the strength of the recycled concrete. However, this effect was less tangible in tensile strength. Third, upon investigating the results of tensile strength, it can be said that the Barcelona test results were closer to the direct tensile test results compared to the Brazilian test results. This indicates the higher viability of Barcelona’s test results. Fourth, the results obtained from the Barcelona tensile test for recycled concrete were closer to the results of the direct tensile test compared to the concrete containing natural aggregates, which suggests that the Barcelona test is more suitable as a tensile test for recycled concrete. Fifth, the effects of various factors on tensile strength were somewhat less compared to the compressive strength, although very close. Sixth, the relationships provided by the regulation for concrete tensile strength on compressive strength were highly inconsistent with the results obtained from the direct tensile test, for which the consistency was higher for concrete containing natural aggregates compared to recycled concrete. Seventh, the dispersion of results obtained from tensile tests was higher for recycled concrete compared to concrete containing natural aggregates, but lesser of this dispersion was observed in the compressive strength.
Originality/value
According to the laboratory results, the strength of concrete containing recycled aggregates becomes closer to the strength of concrete containing natural aggregates whenever the water-to-cement ratio is higher. Upon investigating the treatment conditions, it was observed that the treatment had a greater effect on the strength of the recycled concrete. However, this effect was less tangible in tensile strength. On the basis on the results of the tensile strength, it can be said that the Barcelona test results were closer to the results of the direct tensile test compared to those of the Brazilian test. This indicates the higher viability of Barcelona’s test results. The results obtained from the Barcelona tensile test for recycled concrete were closer to the results of direct tensile test compared to the concrete containing natural aggregates, which suggests that the Barcelona test is more suitable as a tensile test for recycled concrete. The effects of various factors on tensile strength were somewhat less compared to the compressive strength, although very close. The relationships provided by the regulation for concrete tensile strength on compressive strength were highly inconsistent with the results obtained from the direct tensile test, for which the consistency was higher for concrete containing natural aggregate compared to recycled concrete. The dispersion of results obtained from tensile tests was higher for recycled concrete compared to concrete containing natural aggregate, but lesser of this dispersion was observed in the compressive strength.
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Peel strength numbers are part of a laminate's specifications and should characterize the specific bond performance (copper adhesion) under test conditions. Unfortunately, from…
Abstract
Purpose
Peel strength numbers are part of a laminate's specifications and should characterize the specific bond performance (copper adhesion) under test conditions. Unfortunately, from both a theoretical and a practical point of view they are not able to do that. This study seeks to address this issue.
Design/methodology/approach
This paper has been written to show the main impacts on the measured peel strength numbers in the IPC‐TM‐650 peeling test. From an extensive database regarding peel numbers for diverse foil types, foil thicknesses and treatment roughnesses it is possible to show the influence of prepreg type, foil thickness and roughness on the measure peel strength.
Findings
Copper adhesion to laminating resin is insufficiently described by peel strength data because of the impacts of foil thickness, stiffness on bending (physical bending work, stress distribution underneath the peeling line) and the treatment roughness. The latter works reinforcing regarding the (low) resin strength and this influence is measured on resin strength instead of real bond. Fracture due to peeling is cohesive, mostly with a totally intact copper‐resin interface. This is especially true in high performance laminates that show low peel strengths not because of bad copper bonding but because of brittle resins (filled and unfilled).
Originality/value
Users have to understand the limited benefit of the IPC peel test in characterizing copper‐resin bonds. Peel increase on (low bond) high performance resins by increased foil roughness is not a practical way in the field because of no bond improvement (interface) and heavy disadvantages in dielectric thickness (HiPot tests at thin core laminates), respectively.
Hassan A.M. Mhamoud and Jia Yanmin
This study aims to investigate the effectiveness of different additives (individual effects) in improving the strength of concrete to resist temperatures of up to 60ºC.
Abstract
Purpose
This study aims to investigate the effectiveness of different additives (individual effects) in improving the strength of concrete to resist temperatures of up to 60ºC.
Design/methodology/approach
In all, 13 different mixtures with a constant water/binder ratio of 0.36 and grade M40 were prepared by using ordinary Portland concrete alone, or with partial replacement by fly ash (FA), blast-furnace slag, silica fume (SF) and a combination of all three. After 7 and 28 days under water, their strength and residual strength were measured.
Findings
The results of testing revealed that the addition of 10 per cent SF was found to result in the greatest increase in compressive strength and flexural strength along with decreased the residual strengths. The addition of FA increased the compressive strength and enhanced the residual compressive strength. However, it also decreased the residual flexural strength.
Originality/value
The addition of slag achieved better flexural strength and the best residual compressive strength. The combination of additives also enhanced the compressive strength but was not found to be better than using SF alone.
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Nicky Garcea, Stephen Isherwood and Alex Linley
This paper sets out to draw comparisons and make linkages between strengths and competency methodologies. Whereas some authors have seen the strengths approach as a revolution in…
Abstract
Purpose
This paper sets out to draw comparisons and make linkages between strengths and competency methodologies. Whereas some authors have seen the strengths approach as a revolution in human resources (HR), the authors of this paper see it more as a natural evolution. The paper aims to overview the strengths approach as well as presenting a case study of strengths‐based graduate recruitment from the Big Four professional services firm, Ernst & Young.
Design/methodology/approach
The strengths‐based approach to recruitment is described in general, and the particular approach taken to graduate recruitment at Ernst & Young is outlined. Rather than assessing for generic competencies, strengths‐based recruitment seeks to identify the natural strengths of individuals that are aligned to the role for which they are applying. Assessors are trained to look for energy and authenticity, together with evidence of high performance of the strength.
Findings
The strengths‐based graduate recruitment project at Ernst & Young delivered a 15 percent increase in the number of candidates de‐selected at first interview, together with a 12 percent increase in the number of candidates appointed following assessment center, compared with the previous competency approach.
Practical implications
Strengths‐based graduate recruitment provides a robust and reliable methodology for attracting, selecting and appointing the best candidates for the role. It delivers a better candidate experience and builds a more positive and differentiated employer brand.
Originality/value
Ernst & Young is one of the first UK organizations to use strengths‐based graduate recruitment systematically in this way The strengths methodology not only supports its interviewing and assessment centers, but also is used throughout its campus events and through attraction and candidate engagement with an online strengths tool developed and managed by Capp.
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Nicky Garcea, Rebecca Harrison and Alex Linley
The purpose of this article is to set out the ways in which pharmaceutical company Boehringer Ingelheim embedded a strengths-based approach to the assessment and development of…
Abstract
Purpose
The purpose of this article is to set out the ways in which pharmaceutical company Boehringer Ingelheim embedded a strengths-based approach to the assessment and development of field-based staff during a period of structural and culture change. It provides an overview of how strengths-based methodologies were implemented and embedded through this period. It offers a case study example of how Capp partnered with Boehringer Ingelheim to deliver and cascade its assessment and development solutions. It also provides early evaluation data.
Design/methodology/approach
Boehringer Ingelheim introduced strengths through recruitment and development. It built on Capp's strengths methodology and Realise2 tool and model. To aid implementation, cross functional teams were also set up to cascade knowledge and skills across the organizational system.
Findings
The initial findings from this program include quantitative and qualitative data from candidates and assessors demonstrating their positive perception of the assessment and development process.
Practical implications
This article provides case study material, client learning and tips for how other organizations could introduce strengths-based solutions into similar culture change, team and personal development projects.
Originality/value
Boehringer Ingelheim is one of the first UK based organizations explicitly to take a strengths-based approach to aid culture change.
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Yasemin Bulut and Vildan Sülar
The purpose of this paper is to examine the effects of coating process parameters (base fabric, coating material, coating technique and production parameters) on mechanical…
Abstract
Purpose
The purpose of this paper is to examine the effects of coating process parameters (base fabric, coating material, coating technique and production parameters) on mechanical properties of coated fabrics.
Design/methodology/approach
In this research, 24 coated fabrics were produced under controlled production conditions by using two cotton base fabrics and two coating materials as polyurethane (PU), PU/silicone in order to study how coating affects some of the base fabric's mechanical properties such as breaking strength, breaking elongation, tear strength, bursting strength, bending rigidity and abrasion resistance. The measured data were evaluated with variance analysis to determine the effects of the coating parameters at 95 per cent confidence level.
Findings
Breaking strength shows increments for almost all fabrics, whereas breaking elongation values decreased by coating application. Coating has a very clear influence on tear strength of coated fabrics due to the penetration of coating material into the fabric structure. Changes in bursting strength are not similar for two base fabrics with systematically changed production parameters. Coating improves all measured parameters of bending rigidity. Coating application enhances abrasion resistance though some broken fibers are observed on the fabric surface in scanning electron microscopy investigation.
Originality/value
In the past few years, the researches on this area focused on investigating the effects of coating materials and layers on tensile properties. This study comprehensively examines the effects of several coating parameters on mechanical properties such as breaking strength, breaking elongation, tear strength, bursting strength, bending rigidity and abrasion resistance.
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