5,106,548 research outputs found
Global trends in raw materials consumption
Get PDFThis paper reviews movements in raw materials consumption over the past 30 years. Included in this review are all base metals and steel, and important agricultural raw materials. These primary commodities share the common characteristic that they are used as inputs in manufacturing and construction. Some metals and minerals, energy commodities, and timber products are not included in this review for various reasons. The period reviewed is from 1961 to 1988. A prominent characteristic of the metals market during the past 15 years has been its very slow growth. In some years consumption of several raw materials has even declined. Explaining the causes of this slowdown, in the face of moderate economic growth, has become a topical issue. The slowdown has important implications for a number of developing countries that rely heavily on exports of these materials. The severity and persistence of post-1973 declines in metals intensity per unit of GNP, prompted the conjecture that it may have been structural. This paper reviews the debate on this issue, including results of statistical tests. It also summarizes the trends in raw materials consumption and reviews the technological developments relating to raw materials consumption.Mining&Extractive Industry (Non-Energy),Montreal Protocol,Sanitation and Sewerage,Primary Metals,Environmental Economics&Policies
Architecture and materials selection in multi-materials design
Get PDFThe design process involving both the architecture and the materials represents an hard task mainly due to the high number of potential configurations, thus requiring firstly the development of new and more rigorous approaches but also the development of new tools. To this purpose, we present in this work a new strategy for the design of architectured materials. Such a strategy relies on one hand on the construction of some databases for the selection of both geometrical patterns and materials, and on the other hand on the use of well-known analytical models to describe the physical behaviour of the multi-material. In order to prove its effectiveness, we apply our strategy to the problem of the least-weight design of a multilayer plate that has to meet thermal, electrical and mechanical requirements. Moreover, we use a genetic algorithm, as a numerical tool, to perform the solution search for our problem. Numerical results show that we can obtain optimum configurations characterised by a weight saving up to 59% keeping the same (or even superior) thermal, electrical and stiffness properties than those of a monolithic reference plate
Biodegradable materials in dentistry: A comprehensive review of current trends
Get PDFThe dental industry has witnessed a paradigm shift towards biodegradable materials, driven by the need for sustainable and environmentally friendly solutions. Biodegradable materials in dentistry offer a promising alternative to traditional non-degradable materials, providing many benefits for patients, clinicians, and the environment. However, challenges persist, including limited durability and standardized regulations. This review article explores the current state of biodegradable materials in dentistry, including their applications, advantages, and limitations. Further, this article discussed the use of biodegradable materials in dental implants, restoratives, and temporary devices, as well as their potential for tissue engineering and regenerative dentistry. Additionally, the discussion covered the clinical significance, emphasizing the possibility of biodegradable materials transforming dental procedures and reducing their environmental footprint. As the field continues to evolve, biodegradable materials are poised to play a vital role in shaping the future of sustainable dentistry
Fluoride releasing restorative materials: a review
Get PDFFluoride compounds are incorporated as anticariogenic agents in numerous restorative materials. Incorporation of fluoride into restorative materials impart anticariogenic character by various mechanisms including reduction of demineralisation, enhancement of remineralisation, interference of pellicle and plaque and inhibition of microbial growth and metabolism. In addition, the application of the topical fluoride in the form of toothpaste and varnish is also considered as the most effective method of caries prevention. The fluoride combines with HA of the tooth and forms an acid-resistant fluorapatite (FAP) crystals. Also, fluoride enters into the cells of the bacteria and inhibits carbohydrate metabolism, which eventually kills the bacteria. The objective of this review was to emphasise the fluoride-releasing restorative materials available in dentistry
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