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Article
Publication date: 1 April 2002

82

Abstract

Details

Aircraft Engineering and Aerospace Technology, vol. 74 no. 2
Type: Research Article
ISSN: 0002-2667

Keywords

Article
Publication date: 19 August 2021

Oliver Bahr

This paper aims to answer two questions. First, are there any differences in the fire performance of columns made of normal and of high-strength concrete? Second, under…

Abstract

Purpose

This paper aims to answer two questions. First, are there any differences in the fire performance of columns made of normal and of high-strength concrete? Second, under which circumstances does the fire design govern the cross-sectional dimensions of concrete columns? Is it feasible to replace columns out of normal strength concrete by more slender high-strength concrete columns?

Design/methodology/approach

The author conducted numerical studies using the finite element code “Infocad” of the German company “Infograph”. The studies included the effect of different parameters on the fire performance of columns out of normal and high-strength concrete, i.e. the load ratio and eccentricity, boundary conditions and times of fire exposure.

Findings

Results from the numerical investigations showed that high-strength concrete columns suffer much more from heating than normal strength concrete columns. This is the outcome of the unfavourable mechanical properties of high-strength concrete at elevated temperatures. Although the relative fire performance of columns out of high-strength concrete is worse than that of columns out of normal strength concrete, initial load reserves are beneficial to achieve even high fire ratings.

Originality/value

Many researchers addressed in experimental and numerical studies the fire performance of columns out of normal and high-strength concrete. A special emphasis was often laid on the spalling of fire-exposed high-strength concrete. However, there are no systematic investigations when the fire design governs the cross-sectional dimensions of high-strength concrete columns. Based on a previous comparison of the relative fire performance of columns out of normal and high-strength concrete, this paper, hence, addresses the question whether there is a reasonable lower limit for the use of these columns. This is an important aspect for designers since there is a tendency to replace columns out of normal strength concrete by columns out of high-strength concrete. Higher concrete strengths allow for smaller cross sections of the columns, and designers may, hence, increase the usable space of buildings.

Details

Journal of Structural Fire Engineering, vol. 12 no. 4
Type: Research Article
ISSN: 2040-2317

Keywords

Article
Publication date: 14 January 2022

Amir A. Abdelsalam, Salwa H. El-Sabbagh, Wael S. Mohamed, Jian Li, Lihua Wang, Hanafi Ismail, Ahmed Abdelmoneim and Mohsen A. Khozami

This paper aims to study the effects of various compatibilisers (maleic anhydride (MAH), methyl methacrylate/butyl acrylate emulsion lattice, and adhesion system (HRH)) on…

Abstract

Purpose

This paper aims to study the effects of various compatibilisers (maleic anhydride (MAH), methyl methacrylate/butyl acrylate emulsion lattice, and adhesion system (HRH)) on properties of carbon black (CB) filled with natural rubber (NR)/styrene-butadiene rubber (SBR)/ nitrile butadiene rubber (NBR) blends). A series of NR/SBR/NBR blends at a 30/30/40 blend ratio reinforced with 45 phr of CB was prepared using the master-batch method.

Design/methodology/approach

The tensile properties such as the tensile strength, stress at 100, 200 and 300% elongations, and elongation at break (EB)% were studied. Additionally, the morphological properties of compatibilised and uncompatibilised composites were compared to determine the optimal compatibiliser content.

Findings

The influence of compatibilisers appeared on all the properties studied. The properties of the blends compatibilised with prepared emulsion are very distinct from those of blends compatibilised with MAH and adhesion systems.

Research limitations/implications

Interactions among the different components of blends at the interfaces have a high impact on the interfacial properties of the rubber blend.

Practical implications

Compatibilisers significantly improve the physicomechanical properties of the resulting composites with the loading of investigated compatibilisers because of the uniform dispersion of CB in the rubber matrix.

Social implications

Using blends in the rubber industry leads to high-efficiency production of low-cost products.

Originality/value

The rubber blending has a significant positive effect on a wide range of applications such as structural applications, aerospace, military, packaging, tires and biomedical. Hence, improving the compatibility of blends will make new materials suitable for new applications.

Details

Pigment & Resin Technology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 23 March 2010

A.I. Hussain, I.F. Abadir and S.M. El Marsafy

The purpose of this paper is to study the effect of incorporating some inorganic fillers, namely aluminium oxide and aluminium hydroxide on the rheological, mechanical and…

Abstract

Purpose

The purpose of this paper is to study the effect of incorporating some inorganic fillers, namely aluminium oxide and aluminium hydroxide on the rheological, mechanical and thermal behaviour of acrylonitrile‐butadiene rubber (NBR) vulcanizates.

Design/methodology/approach

For improving physico‐mechanical properties of NBR vulcanizates, various compositions were made by incorporating different concentrations of employed fillers with NBR. These properties included the torque, cure time, tensile strength, elongation at break, swelling, diffusivity, as well as thermal behaviour of the loaded and unloaded NBR with fillers were characterised.

Findings

The incorporation of the two investigated fillers improves the thermal behaviour of the vulcanizates, especially aluminium hydroxide. All samples showed more or less a first order decomposition kinetics, for which the activation energy ranged from 177 to 187 kg/mol.

Research limitations/implications

NBR is extensively used industrially for its single, most important property, which is an exceptional resistance to attack by oils and solvents. However, incorporation of fillers in (NBR) leads to the development of improved, competitive properties of the vulcanizate. A further study must be carried out on the flame retarding effect of the fillers, beside the effect of surface treatment of the fillers on the dispersibility and physico‐mechanical properties of the vulcanizates.

Practical implications

The use of two investigated fillers provided a simple and practical solution to improving the resistance to swelling in motor and break oil as well as the thermal behaviour of the NBR.

Originality/value

The use of these fillers was novel and could be used in many rubber industries especially in gasket and oil seals.

Details

Pigment & Resin Technology, vol. 39 no. 2
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 1 February 1991

C. Lea

The three European Community manufacturers of commercially available wetting balances for measuring the solderability of electronic components have participated in an…

Abstract

The three European Community manufacturers of commercially available wetting balances for measuring the solderability of electronic components have participated in an intercomparison assessment of surfaces of standard solderability that have the potential for calibrating the balance instruments. The development of the standard surfaces, as well as the small adjustments needed to improve the uniformity of design of the different instruments, and the standardisation of the procedures for their use, have been described in the preceding papers in this series. This paper gives details of the experimental procedures used for the intercomparison and the significance of the comparative data from each balance type.

Details

Soldering & Surface Mount Technology, vol. 3 no. 2
Type: Research Article
ISSN: 0954-0911

Article
Publication date: 1 November 1982

Beech Aircraft Corporation announced today it is implementing a wing‐structure service‐life programme that will provide Beechcraft King Air owners guaranteed useful wing life.

Abstract

Beech Aircraft Corporation announced today it is implementing a wing‐structure service‐life programme that will provide Beechcraft King Air owners guaranteed useful wing life.

Details

Aircraft Engineering and Aerospace Technology, vol. 54 no. 11
Type: Research Article
ISSN: 0002-2667

Article
Publication date: 5 October 2021

Indunil Erandi Ariyaratne, Anthony Ariyanayagam and Mahen Mahendran

This paper presents the details of a research study on developing composite masonry blocks using two types of mixes, conventional and lightweight mix, to enhance their…

Abstract

Purpose

This paper presents the details of a research study on developing composite masonry blocks using two types of mixes, conventional and lightweight mix, to enhance their fire/bushfire resistance and residual compressive strength.

Design/methodology/approach

Composite masonry blocks (390 × 190 × 90 mm) were fabricated using conventional cement–sand mix as the outer layer and lightweight cement–sand–diatomite mix as the inner layer. Material properties were determined, and all the mixes were proportioned by the absolute volume method. After 28 days of curing, density tests, compression tests before and after fire exposure and fire resistance tests of the developed blocks were conducted, and the results were compared with those of conventional cement–sand and cement–sand–diatomite blocks.

Findings

Developed composite blocks satisfy density and compressive strength requirements for loadbearing lightweight solid masonry units. Fire resistance of the composite block is –/120/120, and no cracks appeared on the ambient side surface of the block after 3 h of fire exposure. Residual strength of the composite block is higher compared to cement–sand and cement–sand–diatomite blocks and satisfies the loadbearing solid masonry unit strength requirements.

Practical implications

Composite block developed in this research can be suggested as a suitable loadbearing lightweight solid masonry block for several applications in buildings in bushfire prone areas.

Originality/value

Limited studies are available for composite masonry blocks in relation to their fire resistance and residual strength.

Details

Journal of Structural Fire Engineering, vol. 13 no. 1
Type: Research Article
ISSN: 2040-2317

Keywords

Article
Publication date: 1 September 1997

Longwu Wu

FEM analysis has been increasingly employed to simulate sheetmetal forming processes for industrial application purposes. From the simulation results, finite element…

Abstract

FEM analysis has been increasingly employed to simulate sheetmetal forming processes for industrial application purposes. From the simulation results, finite element analysts are able to predict the occurrences of splits and wrinkles therefore they can make recommendations of changes to the die design and/or to the part design to avoid possible stamping failures. The number of real die tryouts can be reduced, thus, the design cycle is shortened and manufacturing costs lowered. In the early times, application analysts were mostly concentrated on simulation of the stamping process itself starting from simple models, later running full size 3D models with large number of elements.

Details

Engineering Computations, vol. 14 no. 6
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 10 December 2019

Ayse Kucuk Yilmaz

Each decision-making involves risk; therefore, risk is a strategic element in management and organization. In terms of risk management, the transformation process in…

Abstract

Purpose

Each decision-making involves risk; therefore, risk is a strategic element in management and organization. In terms of risk management, the transformation process in organizations should be aimed at optimizing and improving the most important performance criteria such as cost, quality, flexibility and speed, rather than just as required by legislation. Transformation process has sustainability risks for organizations. ATO transformation process should be well designed. Process also should include clear steps to implement them. Sound and well-designed process will be useful for organizational performance and quality management. The management of the risks of conversion processes is vital for the continuation of operations without interruption. In aviation universities’ approved training organizations (ATOs), each system must be handled and processed separately. Transformation plans should be prepared considering the risks of each system. The purpose of this study is to develop process flowcharts of all systems in sustainable ATO transformation process from risk management perspective.

Design/methodology/approach

Flowchart method is useful to identify process risks in organizational system transformation. Flowcharts simplify communication and provide effective analysis of the process. Flowchart enables designing plan which is suitable for aimed results. Flowcharts method provides efficient coding and system analysis and program development phase also serves as a guide while debugging errors. In this study, flowcharts including all stages have been developed for transition to an ATO authorization. With these flowcharts, all elements of the process and the risks, threats and opportunities that may be faced can be proactively identified together. Thus, improvements will be possible to achieve the corporate objectives of the transformation and reorganization process and increase the corporate performance with optimum resource usage.

Findings

Flowcharts may contribute to the reorganization and transformation of processes in all aviation academies. In this sense, it provides infrastructure for future studies. New studies can be carried out for the reorganization of all departments in aviation. It is believed that this research will contribute to the aviation management literature. Flowchart is also called as process flowchart or process flow diagram. Flowchart is effective methodology to manage transformation process risk. Owing to clarify each step in transformation process, risks may be managed with timely decision-making by managers. In this research, five fundamental flowcharts have been developed in ATO system. These include all processes in transformation as preparation of manuals, new authority application, competent authority inspections, corrective and preventive actions, revalidation and fees in transformation process and its parts. Presented flowcharts may be useful to identify and manage process risk in initial phase as consent with proactive management style.

Research limitations/implications

This research presents designed flowcharts for ATO transformation risk management process. This research may extend at other departments in aviation universities such as air traffic control, maintenance and management.

Practical implications

As a methodology, flowcharts can be considered as schematic algorithms. The flowchart is a detailed representation of the process to carry out a specific task. In this research, flowcharts have been developed for transformation process stages at ATO authorization. These flowcharts are useful for proactive identification of process elements and their risks – threats and opportunities. Thus, improvements will be possible to achieve the corporate objectives of the transformation and reorganization process and increase the corporate performance with optimum resource usage. Flowcharts may contribute to the reorganization and transformation of processes in all aviation academies. In this sense, it provides infrastructure for future studies. New studies can be carried out for the reorganization of all departments in aviation. It is believed that this research will contribute to the management and strategy literature with engineering.

Originality/value

ATO transformation process risk management has not been studied much in literature. The operational manuals of ATO's management and strategy planning prepare according to both legal regulations and handbooks of aviation authorities which obliged for ATO. It is anticipated that this original study may be useful for determining the risks of transformation processes of flight training departments of civil aviation universities and for good process design. Flowcharts may contribute to the reorganization and transformation of processes in all aviation academies. In this sense, this study provides infrastructure for future studies. New studies can be carried out for the reorganization of all departments in aviation. It is believed that this research will contribute to the aviation management literature. Flowchart is also called as process flowchart or process flow diagram. Flowchart is effective methodology to manage transformation process risk. Owing to clarify each step in transformation process, risks may be managed with timely decision-making by managers. The aviation universities operate with authorization. This research may contribute to their process management and strategy to complete their transformation and transition via risk management. Developed flowcharts present all necessary steps to become authorized as an ATO. This research may serve as a kind of framework guide for other aviation organizations to be used in their transformation/transition process.

Article
Publication date: 1 August 2005

S.H. El‐Sabbagh, A.I. Hussain and M.A. Abd El‐Ghaffar

To evaluate the performance of the compatibiliser of epoxidised soyabean oil‐free fatty acid prepared on the NBR/EPDM blends compared with maleic anhydride and also to…

1711

Abstract

Purpose

To evaluate the performance of the compatibiliser of epoxidised soyabean oil‐free fatty acid prepared on the NBR/EPDM blends compared with maleic anhydride and also to explore the effect of loading the compatibiliser NBR/EPDM rubber blend with unmodified and modified polypropylene fibres on the mechanical properties of the blend.

Design/methodology/approach

To achieve desirable rheological and physico‐mechanical properties of NBR/EPDM rubber blend, various compositions were made by incorporating different doses of the compatibiliser of epoxidised soyabean oil‐free fatty acid prepared and maleic anhydride to form NBR/EPDM blends. The effect of loading the compatibiliser rubber blend with unmodified and modified polypropylene fibres on the mechanical properties of the blend was investigated.

Findings

The incorporation of epoxidised soyabean oil‐free fatty acid or maleic anhydride into NBR/EPDM blend greatly enhanced their compatibility improved the rheological, as well as physical properties of rubber blends. The addition of NBR to EPDM improved the motor oil swelling resistance of EPDM. Blending of the two individual rubbers without a compatibiliser generally exhibited a non‐synergistic effect with respect to the physical properties. The strain energy, tensile strength, Young's modulus and strain at yield varied linearly with composition in the presence of compatibiliser, but deviated from linearity in the absence of compatibiliser. Reinforcement of the NBR/EPDM blend with modified polypropylene fibres enhanced the physical properties more significantly than with the unmodified ones.

Research limitations/implications

The compatibiliser of epoxidised soyabean oil was prepared by reacting in situ soyabean oil‐free fatty acid with per‐acetic acid.

Practical implications

The method developed provided a simple and practical solution to improving the rheological and physico‐mechanical properties of the NBR/EPDM rubber blend.

Originality/value

The method for enhancing rheological and physico‐mechanical properties of NBR/EPDM rubber blend loaded with modified polypropylene fibres was very important and showed a synergistic effect and could find numerous applications in the rubber and plastic industries.

Details

Pigment & Resin Technology, vol. 34 no. 4
Type: Research Article
ISSN: 0369-9420

Keywords

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