Papers by Keyword: Review

Abstract: Carbon fiber reinforced silicon carbide composite (C_f/SiC) is the new high temperature ceramic composite developed in recent years, widely used in the aviation, aerospace and other high-tech fields. In this paper, a variety of joining methods of C_f/SiC composite to metallic materials, including active filler brazing, solid phase diffusion welding, liquid infiltration joining, as well as chemical vapor deposition of niobium transition joining technology were introduced. At the same time, the features and disadvantages of each technique were evaluated. This review is intended to provide a comprehensive guide to the design and application of C_f/SiC composite joining to metals.

Abstract: Due to environmental pollution form cement industries, some efforts for alternative construction material are increasing. Recently, geopolymer concrete has drawn attention of researchers and engineers because of its lower carbon print and better mechanical property over Portland cement concrete. According to previous studies, geopolymer concrete results almost up to 90% reduction in carbon dioxide (CO2) emission to atmosphere. Mechanical properties of geopolymer concrete such as compressive strength, durability, sulfate resistance, early strength and low shrinkage are better than Portland cement concrete. In addition, the appropriate usage of one ton of fly ash earns one carbon-credit redemption value of about 20 Euros, and hence earned monetary benefits through carbon-credit trade.Therefore, this paper presents a review on the fly ash-based geopolymer concrete. The paper mainly covers composition, mixing and curing process, benefits, limitations and applications of alkali activated fly ash based geopolymer concrete.

Abstract: This paper has reviewed the failure criteria that had been applied in the wellbore studies. Rock failure studies had applied in the wellbore and reservoir to establish the stability, which is a major problem in oil and gas wells. There problems are both in injection wells and production wells. In injection wells, fracturing is a problem and in production wells, sand production affects the oil flow rate. The stress state of the well determines the stability of the well using the failure criteria.Different failure criteria and their applications had been studied. The theory of the failure has expressed; then applied criteria, formulation and modification of different criteria is expressed for different wellbore studies. And finally the important aspects and differences in wellbore failure rather than the rock surface failure has been discussed.

Abstract: This paper presents a review on gravitational search algorithm (GSA). Nowadays, GSA has been used in various engineering studies such as production cost, production time, power consumption and emission. The GSA also mainly focuses to solve the problem related to optimization, modeling, scheduling and clustering. This paper also highlights the current researches using improved GSA.

Abstract: Certainly, one of the most cost effective and comprehensive infrastructure assets of the build environment is road infrastructure. The environmental impacts of this asset during its life-cycle drive researchers to create a foundational framework to quantify these effects. Life cycle assessment (LCA), a method for the assessment of all modules in a life cycle, has been examined to evaluate all the environmental modules and components of road projects due to constraints of environmental assessments. The enthusiasm for enhancing the sustainable development of basic infrastructure leads to quick expansion on pavement life cycle assessment. An audit of applicable published LCA studies has recognized that environmental modules, such as the usage module (rolling resistance of pavement, carbonation, and albedo), end of life (EOL) module, and components such as traffic congestion during the construction module are not regarded in most of the articles. These modules potentially have the same environmental impact as other regularly considered modules such as materials, transportation, and construction. The goal of this study is to recognize shortfalls in the fields that bolster pavement LCA, to prepare a comprehensive and straight forward methodology, and to provide a basis on which related studies can move forward

Abstract: Laser cutting is one of the key fabrication technologies applied to coronary stent manufacture. This paper reviews the recent progress in laser-based stent manufacturing, including different type of lasers used, laser interaction with different stent materials, process characteristics and quality/productivity issues.

Abstract: In some countries quite a number of construction projects that are either not completed or out rightly abandoned. This paper is an overview on abandoned construction projects, and the causes and effects due to the formidable situation relating to this issue. This was conducted referring to the studies and findings in the thesis and journals on abandoned projects. Few probable causes and effects are identified from various researchers based on studies conducted by them on this issue. It is found that most of the studies on the related matter was conducted mainly using questionnaires and also by conducting interviews with the relevant parties. There were various probable causes and implications that was identified from the studies and analysis that was carried out, which does not differ much from one another, and in fact some have suggested the mitigation measures for this issue. After reviewing the research and studies that has been conducted on the issue of abandoned projects, as a conclusion, it is notable to have a more thorough investigation on the existing problem up to this date and look into the whole issue from different aspects in depth.

Abstract: This paper presents a review of China’s technological development in the 20th century. The purpose of the review is to study the major technological inventions achieved by China in the 20th century that has brought significant impact to China’s technological development. In the 20th century, China has made great achievements in the field of space technology and also atomic energy. In space technology, China launched its very first satellite, Dong Fang1 (DFH1) (translated as Red East 1) and continued to improvise it in terms of performance in the field of spaceflight technology. In the same century, China also explored the area of atomic energy by building its very first nuclear-powered submarine, Chang Zheng 1 (translated as Long March 1). These technological developments achieved in the 20th century allowed China to be a step ahead of many other countries towards the advancement of technology. It is hoped that this review on China's influential role in the technological developments of the 20th century can be used as a useful references for other countries that wish to embark upon rapid and progressive technological developments.

Abstract: After years of pure academic interest and niche applications, today the flow forming process is growing in its importance in the forming industry, due to increasing demand in aerospace, automotive and defense industries. The review surveys academic paper of last fifty years, in order to evaluate the current state of art for academic and practitioner. Theoretical and experimental approaches are collected and compared evaluating their prediction models. Several knowledge gaps can be identified. Stress and strain tensors evolutions are not determined for workpiece, due to high computational cost and missing identification of correct finite elements approach. Final microstructure is often evaluated case by case but its evolution during plastic deformation is not studied. Residual stress and final material proprieties, as corrosion behavior, have been not studied numerically or experimentally. Tool path impact and alternative geometries are not deeply explored. Process experimental optimization and characterization through Design of Experiment is still limited to a few papers and usually not well developed.

Abstract: Ceramic materials present interesting properties and generate products that meet engineering requirements referring to this class for several applications. Aluminum oxide is a very good example of this class of materials, being applied widely in high technology areas especially where the abrasive and erosive wear are strongly demanded. Many factors interfere on the wear of alumina: material composition, characteristics of the used oxides, and the manufacturing process that defines the final microstructure. It is know that the grain size of the alumina has a strong influence on the wear rate and is the focus of several studies. The grain growth during sintering as well as the diffusion process can be controlled by using dopants in the alumina composition. Thus the aim of this paper is to present a review about the dopants interference on the grain size of alumina, which in turn influences the wear behavior of the alumina. The results described allow broad understanding on the subject