Tempering characteristics of a Cu-AI-Ag Alloy

ALUMINIUM- BRONZES , particularly those containing 10 or more of aluminium, have a great potential as future engineering materials. Extensive rescarch is being carried out at present for the development of aluminium - bronzes. Various steps for improving the mechanical properties of these alloys have been recently reviewed.1 One possib-ility is to utilise the effect of ternary elements on mechanical properties and heat treatability of aluminium - bronzes

Tempering Characteristics of A Cu-Al-Ag Alloys

Aluminium bronzes, particularly those containing 10% or more of aluminium, are a very promising system of alloys as future engineering materials. Extensive research is being carried out at present for the development of aluminium bronzes. Various steps for improving the mech-anical properties of these alloys have been recently revi-ewed. One possibility is to utilise the effect of ternary elements on mechanical properties and heat treatability or aluminium bronzes

Non-fusion joining of aluminium

JOINING of aluminium is now a well established techn-ology. Successful joining can be done by TIG and MIG welding, pressure welding processes, brazing and solde-ring processes. Conventional fusion processes of joining aluminium are well known and are widely used in India by all major fabricators. On the other hand, though non-fusion joining processes like soldering, brazing and pressure welding have wide field of applications the correct process and material required are not very well known ; as such there is a specific need in India, at present, to disseminate the knowledge on joining of aluminium especially by these processes which a small fabricator can handle

Studies on the Insecticidal and Repellent Properties of the Seed Extract of Tephrosia Purpurea (LINN) Pers

Laboratory and field trials were conducted to find out the insecticidal and repellent properties of petroleum ether extract of the seeds of Tephrosia purpurea. In laboratory trials contact toxicity of the extract was assessed against land leeches, houseflies, mosquitoes, rice weevil and flour beetle. In field trials, the repellency of the extract was assessed against land leeches, mosquitoes and simulium flies. In laboratory trials, the dosage required for 100 per cent mortality was 0.0005 gm/cm/sup 2/ for land leeches, 0.0157 gm/cm/sup 2/ for flour beetle. In field trials, the extract was found to be repellent against land leeches for 5 hours, mosquitoes for 4 hours and simulium flies for 5 hours

Multiscale characterization of damage tolerance in barium titanate thin films

Barium titanate is a brittle, lead free ferroelectric and piezoelectric ceramic used in patterned and thin film forms in micro- and nano-scale electronic devices. Both during deposition and eventually during service, this material system develops stresses due to different loads acting on the system, which can lead to its failure due to cracking in the films and/or interface delamination. In situ microcantilever bending based fracture experiments and tensile tests based on shear lag tests in combination with digital image correlation were used to understand the cracking behavior of barium titanate films when deposited on flexible substrates. For the first time, the fracture behavior of these nanocrystalline barium titanate films has been quantified in terms of fracture toughness, fracture strength, and interface shear stresses for different film thicknesses. Critical defect size is estimated using the above information as a function of film thickness. It is found that damage tolerance in terms of fracture strength depends on film thickness. Furthermore, compared to a bulk single crystal, barium titanate fracture resistance of the nanocrystalline thin films is reduced. Both effects need to be considered in engineering design of reliable devices employing micro- and nano-scale barium titanate thin film structures

Precise time and frequency intercomparison between NPL, India and PTB, Federal Republic of Germany via satellite symphonie-1

A time and frequency intercomparison experiment conducted using Earth stations in New Delhi, India and Raisting, FRG is described. The NPL clock was placed at New Delhi Earth Station and the Raisting Clock was calibrated with PTB/Primary standard via LORAN-C and travelling clocks. The random uncertainity of time comparisons, represented by two sample Allan Variance sigma (30 seconds), was less than 10 nanoseconds. The relative frequency difference between the NPL and Raisting Clocks, SNPL, RAIS, as measured over the 44 days period was found to be -15.7 x 10 to the -13th power. The relative frequency difference between PTB Primary Standard and Raisting Clock, SPTB, RAIS, during this period, was measured to be -22.8 x 10 to the -13th power. The relative frequency difference between NPL clock and PTB Primary Standard, SNPL, PTB, thus, is +7.1 x 10 to the -13th power. The clock rate (UTC, India) of +7.1 + or - 0.5 x 10 to the -13th power, agrees well with that obtained via VLF phase measurements over one year period and with USNO travelling clock time comparisons made in September, 1980

Prospects of Pigeonpea Hybrids in Indian Agriculture

Stagnant production, soaring prices, and enhanced imports of pigeonpea (red gram) have been matter of concern to the prime stakeholders in India. A new hybrid pigeonpea breeding technology, developed jointly by the International Crops Research Institute for the Semi-arid Tropics (ICRISAT) and Indian Council of Agriculture Research (ICAR) is capable of substantially increasing the productivity of red gram, and thus offering hope of pulse revolution in the country. The hybrid technology, based on cytoplasmic nuclear male-sterility (CMS) system, has given an opportunity of achieving the long-cherished goal of breaking yield barrier in pigeonpea. In the past two years ICRISAT and ICAR have tested over 1000 experimental hybrids and among these GTH 1 and ICPH 2671 were found the most outstanding. GTH-1 has yielded 32% more yield than best local variety, GT 101. ICPH 2671 is highly resistant to fusarium wilt and sterility mosaic diseases and produced 38% more yield over the popular variety Maruti in multi-location trials conducted for over four years. In the on-farm trials conducted in the states of Maharashtra, Karnataka, Andhra Pradesh, Madhya Pradesh, and Jharkhand during 2007, 2008 and 2009 have demonstrated 30% yield advantage over local check varieties. So far the progress in the mission of enhancing the productivity of pigeonpea has been encouraging and the reality of commercial hybrids is just around the corner. The new hybrid pigeonpea will serve as the platform for the tremendous growth of pulse production in India

A new cytoplasmic nuclear male-sterility system derived from cultivated pigeonpea cytoplasm

Cytoplasmic male-sterility (CMS) in pigeonpea has been reported when some wild relatives of pigeonpea were crossed as the female parent with cultivated types as the male parent. In this paper we report a new source of CMS developed by using the cultivated pigeonpea as the female parent and one of its wild relative Cajanus acutifolius as the pollen donor. This is the first report in pigeonpea where CMS has been developed using the cytoplasm of cultivated pigeonpea. Several pure line cultivars of pigeonpea restored pollen fertility whereas cv. HPL 24 partially maintained male-sterility. The wild species C. acutifolius used as one of the parents, maintained complete sterility. Cytological analysis revealed that both in male-sterile as well as the fertile floral buds, meiosis proceeded normally till the tetrad stage. However in the male-sterile genotypes during the formation of tetrads, the pollen mother cell (PMC) wall did not dissolve to release the tetrads unlike in the fertile genotypes and this major event was found to be responsible for male-sterility

Production of hybrids between Cajanus acutifolius and C. cajan

There are many wild species of pigeonpea which are endemic to Australia. These wild species are cross incompatible with cultivated species of Indian origin. Cajanus acutifolius is one such species which does not easily cross with cultivated pigeonpea. Interspecific pollinations lead to hybrid seeds which were semi-shrivelled. Very few seeds germinated to give rise to F1 plants. Backcrossing the hybrid plants to C. cajan, the male parent, gave rise to aborting seeds which did not germinate in vivo hence BC1 plants are obtained after saving the aborting embryos in vitro. BC1 plants showed normal meiotic pairing, but had low pollen fertility. The reasons for embryo abortion and low pollen fertility in spite of normal meiosis could be due to the effect of wild species cytoplasm