Table top, pulsed, relativistic electron gun with GV/m gradient

We present the design and performance characteristics of a compact high voltage pulser with 150 ps rise time, 0.2 to 2 ns adjustable flat top and up to 1 MV amplitude on a 80 Ohm load or up to 0.5 W on a 20 Ohm load, at 1 Hz repetition rate. Combination of a laser triggered SF{sub 6} and a liquid cap is used to form the fast rising pulse and maintain a low jitter between the laser, external trigger, and the high voltage pulsed output. The dark current and breakdown studies with this pulse applied between the electrodes of a diode indicate that fields up to 1 GV/m could be supported by stainless steel and copper cathodes without breaking down. The dark current from a conditioned cathode in a background pressure of 10{sup -7} Torr is below the detection limit of 0.5 mA of our system. Photoemission studies had been conducted with 300 kV applied between copper cathode and stainless steel anode separated by 2 mm. KrF laser of 5 eV photon energy and 20 ns FWHM was used to irradiate the cathode. In these preliminary measurements, 3 nC charge and corresponding quantum efficiency of 3.5 x 10{sup -4} have been obtained. Future plans include increasing the gradient to GV/m range, decreasing the laser pulse duration to ps and subps range and increasing the electron energy to a few MeV

Comparative study of traditional and improved containers for transportation of fresh fish

Traditional bamboo basket and expanded polystyrene insulated plywood box (second hand tea-chest) were compared for transportation of iced marine, fresh water and brackish water fishes from Kakinada to Madras by rail. Quality of fish at dispatching and receiving centres was assessed by organoleptic, total volatile nitrogen (TVN) and total bacterial count (TBC) tests. Based on the results obtained and the prices fetched, the traditional bamboo basket apart from being cheaper was found to be as good as expanded polystyrene insulated plywood box for short distance transportation of iced fish involving less than 24 hours journey

A high stability Nd:YAG photocathode drive laser

A versatile, highly stable, reliable Nd:YAG laser is in operation at Brookhaven Accelerator Test Facility (ATF) for illuminating a metal photocathode RF electron gun. This system addresses stringent requirements on pulse duration, pulse timing jitter, pulse energy, spatial profile, and pointing imposed by electron accelerator experiments. This paper describes the oscillator operation, (which also includes control of a semicconductor switch for ATF`s high power CO{sub 2} laser), beam transport to the cathode, etc

On the stranding of whales along the Tamil nadu and Andhra coasts

Two young female pilot whales Globicephala macrorhyma were caught in the gill nets by a 10 m mechanised boat at Pudukuppam near Cuddalore along the Tamil Nadu coast. The two whales measured 3.02 and 1.40 m in total length respectively. . The fishermen atPomraaiyarpalayam near Pondicherry noticed a whale identified as young female sperm whale Physeter macrocephalus which measured 5.55 m. T he local fishermen at MotupalJy near Ramachandrapuram in Prakasam District of Andhra Pradesh noticed a whale was identified as blue whale Balaenoptera musculu. The various morphometric measurements of these whales listed in detail and tabled

Breadwinners and Homemakers: Migration and Changing Conjugal Expectations in Rural Bangladesh

The literature on marriage norms and aspirations across societies largely sees the institution as static – a tool for the assertion of masculinities and subordination of women. The changing meanings of marriage and conjugality in the contemporary context of globalisation have received scant attention. Based on research in rural Bangladesh, this article questions the usefulness of notions of autonomy and dependence in understanding conjugal relations and expectations in a context of widespread migration for extended periods, especially to overseas destinations, where mutuality is crucial for social reproduction, though in clearly genderdemarcated domains

Effect of Soil Management Practices on Runoff and Infiltration Processes of Hardsetting Alfisol in Semi-Arid Tropics

Alfisols oi Semi-Arid Tropics (SAT) are often chiiractcriscd as structurally unstable (EL-Swaify et 31.. 1905). Under the impact of raindrops the structural instability leads to formation of a seal on the surface. The surface seals rcducc infiltration and increase runoff (Moore, 1981 1. As a result, plant-available water in the profile gets reduced. In most of the SAT Alfisols crop yields arc constrained by the plant-available water