Corrosion of Aircraft Aluminium Alloys in Acid Solutions & its Prevention by Inhibitors

THE corrosion of metals is a serious problem confronting the industrially advanced countries of the world. Modern developments and war-time experiences have made it possible to manufacture metals at lower costs than before. Secondly, new sources of minerals have been discovered, thereby enabling each nation to increase its capacity for the production of metals. Iron and steel, aluminium, copper and zinc are amongst the metals in common use. In practice all of them are liable to corrode in various environments : atmosphere, soil and liquid medium. The loss of metal due to corrosion necessitating repair or removal of metal parts is one of fundamental importance affecting the economy of a country. The cost of corrosion control is rather high, the estimated figures per annum for some of the countries being U.S.A.' close to 10 billion dollars, U.K.2 600 million pounds, Canada3 500 million dollars, Australia4 100 million pounds. and India5 154 crore rupees. It becomes incre-asingly important to preserve available metals in use since a time may come when some of them approach exhaus-tion. From the available figures it has been indicated that immediate attention should be given to the non- ferrous metals, and greater attention to ferrous res-ources. In the case of iron the losses due to corrosion are estimated to be about 7.6 per cent a year. Corrosion control methods, therefore, assume great importance6

Utilization of phosphorus for casein biosynthesis in the mammary gland. II. Incorporation of P<SUP>32</SUP> into free phosphopeptides of milk and of mammary gland

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A micro-convection model for thermal conductivity of nanofluids

Increase in the specific surface area as well as Brownian motion are supposed to be the most significant reasons for the anomalous enhancement in thermal conductivity of nanofluids. This work presents a semi-empirical approach for the same by emphasizing the above two effects through micro-convection. A new way of modeling thermal conductivity of nanofluids has been explored which is found to agree excellently with a wide range of experimental data obtained by the present authors as well as the data published in literature

An ab initio and matrix isolation infrared study of the 1:1 C<SUB>2</SUB>H<SUB>2</SUB>-CHCl<SUB>3</SUB> adduct

The details of weak C-H&#183;&#183;&#183;&#960; interactions that control several inter and intramolecular structures have been studied experimentally and theoretically for the 1:1 C2H2-CHCl3 adduct. The adduct was generated by depositing acetylene and chloroform in an argon matrix and a 1:1 complex of these species was identified using infrared spectroscopy. Formation of the adduct was evidenced by shifts in the vibrational frequencies compared to C2H2 and CHCl3 species. The molecular structure, vibrational frequencies and stabilization energies of the complex were predicted at the MP2/6-311+G(d,p) and B3LYP/6-311+G(d,p) levels. Both the computational and experimental data indicate that the C2H2-CHCl3 complex has a weak hydrogen bond involving a C-H&#183;&#183;&#183;&#960; interaction, where the C2H2 acts as a proton acceptor and the CHCl3 as the proton donor. In addition, there also appears to be a secondary interaction between one of the chlorine atoms of CHCl3 and a hydrogen in C2H2. The combination of the C-H&#183;&#183;&#183;&#960; interaction and the secondary Cl&#183;&#183;&#183;H interaction determines the structure and the energetics of the C2H2-CHCl3 complex. In addition to the vibrational assignments for the C2H2-CHCl3 complex we have also observed and assigned features owing to the proton accepting C2H2 submolecule in the acetylene dimer

Measuring the quantum efficiency of single radiating dipoles using a scanning mirror

Using scanning probe techniques, we show the controlled manipulation of the radiation from single dipoles. In one experiment we study the modification of the fluorescence lifetime of a single molecular dipole in front of a movable silver mirror. A second experiment demonstrates the changing plasmon spectrum of a gold nanoparticle in front of a dielectric mirror. Comparison of our data with theoretical models allows determination of the quantum efficiency of each radiating dipole.Comment: 4 pages, 4 figure

Exploited marine fishery resources off Tuticorin along the Gulf of Mannar coast

Tuticorin coast of Gulf of Mannar is endowed with rocky bottom, coral reefs and sea grass beds with characteristic flora and fauna. It also acts as home for several endangered marine mammals, sea cows and marine turtles. These resources were exploited by a variety of gears during 2000-2005