Science led vs design led teaching approaches in materials science and engineering for aeronautical engineering students

A comparison on teaching styles has been conducted by analysing behavioural, cognitive, developmental, social cognitive and constructivist perspectives of 26 students (higher engineering apprentices). All of those students are in their full-time employment at Broughton factory (Airbus UK) and were comprehensively surveyed at the end of module (ENGF405: Composites and Aeronautical Materials) to quantify their learning experiences. It is generally assumed that design led, in comparison to science led, approach is the most appropriate method for these hands-on engineering professionals. However, presented results are quite interesting because majority of the high achievers have opted for science led approach for their improved learning experiences during the module

Epoxy – the hub for the most versatile polymer with exceptional combination of superlative features

Epoxy resins and epoxy based materials have experienced significant advancement since their beginning in 1936, when Dr. Castan of Switzerland and Dr. Greenlee of USA succeeded in synthesizing the very first bisphenol-A-based epoxy resins. Whether it is the new carbon fiber composite of Boeing’s Dreamliner or the thin set terrazzo flooring, epoxy has always been the ideal choice because of its superlative properties and unique chemical composition. Belonging to thermoset family, it is certainly one of the most versatile polymers we see around in composites, aerospace, automotive, marine, sports materials, construction, structures, electrical and electronic systems, biomedical devices, thermal management systems, adhesives, paints and coatings, industrial tooling and other general consumer products. Because of its versatile nature, epoxy is replacing many conventional materials, e.g. epoxy based materials have already replaced wood in majority of the boats and various sports goods. Epoxy is an open-access journal and offers a fast and comprehensive peer-review. To ensure that the journal has the largest possible impact in this early phase, no publication fees will apply until the end of 2015

Carbon nanotubes for epoxy Nanocomposites: a review on recent developments

Carbon nanotubes (CNTs) are one of the strongest and stiffest engineering fibres. Due to their unique combination of chemical and physical properties at an incredibly small size, they possess great potential to be used as nanofillers for many structural and functional materials, particularly in aerospace sector. Depending on the type, geometrical parameters, concentration, dispersion and many other factors, CNTs can significantly modify the mechanical, electrical and thermal properties of epoxy based materials. This review paper, covering methods of synthesis, composite processing techniques and properties, presents an overview of develop-ments in the field of CNT/ epoxy nanocomposites in recent years

Re-agglomeration of carbon nanotubes in two-part epoxy system; influence of the concentration

Carbon nanotubes, because of their exceptional mechanical properties, are one of the potential reinforcements for polymers in near future. Before substituting these nanocomposites in commercial applications, there are many problems, like dispersion, agglomeration, cost effectiveness etc., which need to be sorted. Processing such nanocomposites for longer durations is quite frequently observed these days. Apart from the other major obstacles, re-agglomeration, because of strong van der walls forces between carbon nanotubes, is one of the latest problems that has been always underestimated and ignored. In this study, different carbon nanotubes (Single-wall nanotubes (SWNT), Double wall nanotubes (DWNT), Amino-modified double wall nanotubes (DWNT-NH2), Thin Multi wall nanotubes (MWNT) and COOH-modified thin multi wall nanotubes (MWNT-COOH)) at different concentrations (0.025, 0.05 and 0.1 %wt) in two-part epoxy system (Liquid Epoxy, Liquid hardener and Liquid epoxy-hardener mixture) were studied involving nano-particle size analyzer. After a study of 3 hours, it was observed that there is a strong dependence of re-aggregation profile on the employed homogenizing technique, i.e. high-power bath ultrasonication in this study. Apart from nanotubes/epoxy mixture, higher concentrations yielded higher aggregates profile and vice versa. Re-agglomeration, with the passage of time, in liquid epoxy was found to be least as compared to liquid hardener and liquid epoxy-hardener mixture. Hardener in liquid-epoxy mixture was the main culprit responsible for re-aggregation. Results were further verified by scanning electron microscopy, which revealed significant differences in the microstructures of the cured and fractured samples. Suggestions for altering processing parameters in order to avoid this major obstacle are discussed

Vibration and buckling of cross-ply composite beams using refined shear deformation theory

Vibration and buckling analysis of cross-ply composite beams using refined shear deformation theory is presented. The theory accounts for the parabolical variation of shear strains through the depth of beam. Three governing equations of motion are derived from the Hamilton’s principle. The resulting coupling is referred to as triply coupled vibration and buckling. A two-noded C1 beam element with five degree-of-freedom per node is developed to solve the problem. Numerical results are obtained for composite beams to investigate modulus ratio on the natural frequencies, critical buckling loads and load-frequency interaction curves

Comparative Study Between Mixed Model Assembly Line And Flexible Assembly Line Based On Cost Minimization Approach [TS167. F278 2008 f rb].

Mixed Model Assembly Line are widely used to produce different models as per customer's demands. Barisan Penggabungan Model Campuran digunakan secara meluas untuk menghasilkan model-model yang berbeza mengikut kehendak pelanggan

Rapid microwave processing of epoxy nanocomposites using carbon nanotubes

Microwave processing is one of the rapid processing techniques for manufacturing nanocomposites. There is very little work focussing on the addition of CNTs for shortening the curing time of epoxy nanocomposites. Using microwave energy, the effect of CNT addition on the curing of epoxy nanocomposites was researched in this work. Differential scanning calorimetry (DSC) was used to determine the degree of cure for epoxy and nanocomposite samples. CNT addition significantly reduced the duration for complete curing of epoxy nanocomposites. As compared to monolithic cured epoxy, 20.5% of decrease in time and 12.5% decrease in spent consumed energy were observed for 0.2 wt.% CNT filled epoxy nanocomposite

Pay and Job Satisfaction: A Comparative Analysis of Different Pakistani Commercial Banks

This paper endeavors to study the various factors of job satisfaction among different commercial bankers in Pakistan and highlight the findings by performing statistical techniques like regression and correlation to gauge level of significance for the factor. Pay has been considered as the major factor for job satisfaction however other related factors like promotion, recognition, job involvement and commitment are also taken into account. Job satisfaction is an attitude of an employee over a period of his job so the factors of satisfaction and dissatisfaction changes over the period. It is a relative term and is nowadays used as a key factor to gauge the performance of a particular employee and organization. Satisfied employees are more likely to be friendly and responsive which attracts customers. Dissatisfied employees can lead to customer dissatisfaction.Job Satisfaction, Pay, Banker

Improving oxidation resistance of carbon nanotube nanocomposites for aerospace applications

Carbon nanotubes (CNTs) based materials possess strong potential to substitute various functional materials developed exclusively for aerospace applications. However, because of the low oxidation temperature of CNTs (400-500 oC), using CNT based ceramic nanocomposites in high temperature applications can be problematic. Making ceramic-CNT nanocomposites by atomic layer deposition (ALD) method and field assisted sintering technology (FAST) is a good route to improve oxidative stability of CNTs. In this study, thermo-gravimetric analysis (TGA) of alumina coated CNTs (prepared by ALD) and alumina-CNT nanocomposites (prepared by FAST) were carried out. 16% improvements were observed in the oxidation resistance for alumina-CNT nanocompo-sites prepared by ALD and SPS techniques. Different strategies to improve oxidation resistance are discussed

Post-liberalisation Efficiency and Productivity of the Banking Sector in Pakistan

It has been long debated in economic literature whether financial markets play a significant role in economic growth and development. [For review see Gertler (1988) and Levine (1997)]. Findings of some recent empirical literature show that well-functioning financial system plays an instrumental role in economic growth, and the causality runs from finance to growth [for cross country evidences see King and Levine (1993, 1993a); Levine and Zervos (1998); Levine, Loayza and Beck (1999); Beck, Levine, and Loayza (1999)]. This, in turn, has led to a search for the key factors that determine the better functioning financial markets. Within the banking sector, efficiency is the core concern of both academics and bank officials. A number of studies have sought to measure the efficiency of financial institutions, to identify the factors that contribute to efficiency of financial system, and to recommend the ways to attain the peer group efficiency levels [Berg (1993); Leaven (1999); Berger and Mester (1997); Miller and Noulas (1996)]. These empirical findings suggest a healthy competitive financial market pave the way for efficient market participants that leads to overall efficiency of the system and hence productivity. Following this notion, liberalisation of financial markets has been initiated to improve the performance of financial institutions both in developed and developing countries. Some empirical tests have been carried out to measure the effects of liberalisation and deregulation of financial institutions on the efficiency and productivity of banking sector.