Powder Metallurgy & its Application to Non-Ferrous Metals

The paper introduces the subject of powder metallurgy based on the studies of bond which exists between two atomically smooth surfaces when brought close together. After dealing with the theoretical principles and practical results of sintering homogeneous as well as heterogeneous powders,the applications of powder metallurgical technique to non-ferrous metals and alloys are discussed at length. -Recent notable developments in powder metallurgy, in the field of heat-resistant metallic compositions, essentially of non-ferrous compositions, are dealt along with other developments such as the modern liquid disintegrator method for making metals and alloys into powder and infiltration technique. The paper deals with cermets and latest carbide compositions. The paper concludes with a reference to the possibilities of applying powder metallurgical techniques to Indian nonferrous industries

Scenarios of Waste and Resource Management: for Cities in India and Elsewhere

Rising prosperity around the globe – welcome and overdue in many respects – has certain undesirable consequences. It leads to an increase in the demand for raw materials, putting pressure on our limited natural resources. At the same time, due to dominant linear economic models of make-use-throw, increasing prosperity also leads to generation of waste. Rising quantities of waste are a global challenge. The challenge manifests itself most visibly in large cities around the world but is more acutely felt in developing countries. Dealing effectively with rapidly increasing amounts of waste is a complex management challenge. Environmental, business, political and social considerations play a role. This report suggests a framework for working through these complexities by focusing on two critical and interconnected questions. First, is waste conceived of as a burden to be got rid of or a resource for generating income and employment? Second, is the waste/resource managed by actively engaging the urban informal sector or tolerating the informal sector merely on the margin? The latter is a burning issue for cities with many poor people. The report identifies four future scenarios of this complex waste/resource management landscape using tools from Foresight methods and political economy analysis. We also identify the dynamics within and across the four scenarios. Although the four scenarios developed in the report represent stylised constructs, they were developed in a participatory workshop and represent stakeholders’ views about their current problems and future ambitions. At the same time, they represent political choices that would influence the development of a particular approach of waste/resource management in a city. Our results have implications for enhancing understanding of the policy choices that can be made today to influence waste/resource management in the future. The methods and results also offer insights into future research on waste/resource management.UK Department for International Developmen

Theoretical considerations for substitutions in alloy steels

THE development of materials possessing certain specific properties was followed on empirical basis in the past. This was specially true in alloy steels, where there are plenty of complications and variables, each effecting the properties sought in its own way. As the theoretical background of this behaviour was least understood, development of materials in the nine-teenth and early twentieth century was based on very laborious approach which was time consuming on the first hand and costly on the other hand. Quite lately attempts have been made to rationalise the metal science on more scientific basis, and although the dream of the designing alloys by slide rule, posse-ssing the required properties, is still far from being achieved, the production costs and wastage in time can be avoided to a considerable extent by it proper application of the factors which have been understood lately. It is the object of this paper to describe these factors in detail so that the attempts in future will he based on more realistic and scientific lines than hitherto followed

Research and development work on substitute electrical resistance alloys for heating elements

From the start of the Second Five- Year Plan great emphasis has been laid on production and utilisation of electric power in various industrial and domestic appliances. Electric heating is thus gradually repla- cing solid-fuels, gas and oil heating . Increasing application of electric heat with all its attendant advantages will fail to register full impact unless suitable electrical heating elements , having long high temperature service life are indigenously avai- lable at reasonable cost

An improved PV system with auto-protection to inject active power into the power grid of marine ships

1132-1142Photovoltaic (PV) system is turning into an ideal secondary power source for marine ships because of the ability to trap nature’s green energy. In this paper, a ship’s power grid connected PV system is proposed. The proposed system will help to inject the active power into the ship’s electric power grid together with a protection scheme, which will prevent the PV system and ship’s power grid from different faulty conditions. The proposed system has facility to track the maximum power point (MPP) of PV array by means of hybrid MPPT method and flyback DC-DC converter. Space vector pulse width modulation (SVPWM) technique controlled 3-phase full-bridge VSI is used to convert DC bus voltage into useful 3-phase AC output in order to feed the local load and transmit excess AC power into the ship’s bus. Furthermore, an isolation transformer is used to provide galvanic isolation amid PV system and ship’s power grid

Research and Development work on Substitute Nickel-Free Austenitic Stainless Steels

THE demands of austenitic stainless steel as what is termed as `non-magnetic' in the Indian market in sheet, plate, tube and rod forms have been multiplying during each successive Five-Year Plan.Due to severe import restrictions, acute and chronic shortage of foreign exchange, the actual import figures tend to taper off and do not represent the actual requirements of the country including stainless sheet used specifically for engineering, chemical and dairy industries incl- uding utensil-making and household hardware. The engi-neering uses of the stainless steel have also multi-plied with the rising tempo of industrial growth. Likewise, stainless steel finished items and assembled components of composite equipment etc. represent an `invisible' demand for heavy imports in one form or the other. About a decade back, the import of stain- less sheet alone represented about Rs 7-8 crores (Rs 70-80 million) of import bill in foreign exchange annually. This figure will double or treble itself, were import restrictions to be removed

Substitution of galvanising by aluminising of steels

ALUMINISING has been accepted by the Government of India as it substitute for galvanising because of the existing scarcity of zinc. Zinc resources of our country are limited whereas minerals for extraction of aluminium are available in plenty. The Hindustan Steel (P ) Ltd., has decided to have provision for strip aluminising plant at Rourkela and Tata Iron and Steel Co. Ltd., may also be going for strip alum-inising adopting the Sendzimir Process . Bokaro Steel Plant has also made provision for aluminising of steel strip

Development of substitute high temperature creep resistant alloys

HIGH temperature creep resistant super strength alloys invariably contain considerable amounts of Ni,Co,W, etc. as alloying additions, in respect of which India lacks in raw material resources. Extensive work has been carried out on development of Cr-Mn-N type austenitic steels as substitute for 18 Cr 8 Ni austenitic stainless steel and their aging behaviour have been extensively studied at the National Metallurgical Laboratory in the last decade. The present work has been initiated to further study the high temperature creep behaviour of Cr-Mn-N type austenitic steels with a view to evolving suitable compositions and heat-treatment to obtain opti-mum high temperature creep strength and rupture ducti- lity in these alloys. In this group of steel Mn and N are used as the chief austenitic stabilizers besides C

Groundnut its nutrition and fertilizer responses in India

THE cultivated groundnut Arachis l~ypogaea L, originated in South America and is now grown in 82 countries in the world and India is the largest producer of the crop. India, China, Nigeria, USA and Senegal account for four-fifths of the world's groundnut production. Groundnut was introduced in India in the 16th century. The area under the crop, however, was rather small till the beginning of the present century. being around one lakh hectares. It increased progressively to 6 lakh hectares by the end of the First World War and to 45 lakh hectares by 1950.........

Effect of HSV-2 Suppressive Therapy on Genital Tract HIV-1 RNA Shedding among Women on HAART: A Pilot Randomized Controlled Trial

Background. The role of suppressive HSV therapy in women coinfected with HSV-2 and HIV-1 taking highly active antiretroviral therapy (HAART) is unclear. Methods. 60 women with HIV-1/HSV-2 coinfection on HAART with plasma HIV-1 viral load (PVL) ≤75 copies/mL were randomized to receive acyclovir (N = 30) or no acyclovir (N = 30). PVL, genital tract (GT) HIV-1, and GT HSV were measured every 4 weeks for one year. Results. Detection of GT HIV-1 was not significantly different in the two arms (OR 1.23, P = 0.67), although this pilot study was underpowered to detect this difference. When PVL was undetectable, the odds of detecting GT HIV were 0.4 times smaller in the acyclovir arm than in the control arm, though this was not statistically significant (P = 0.07). The odds of detecting GT HSV DNA in women receiving acyclovir were significantly lower than in women in the control group, OR 0.38, P < 0.05. Conclusions. Chronic suppressive therapy with acyclovir in HIV-1/HSV-2-positive women on HAART significantly reduces asymptomatic GT HSV shedding, though not GT HIV shedding or PVL. PVL was strongly associated with GT HIV shedding, reinforcing the importance of HAART in decreasing HIV sexual transmission