NOPR Collection:

Development of High Power Coupled-Cavity Travelling Wave tube (CC-TWT)

Sat, 01 Dec 2001 00:00:00 GMT

Title: Development of High Power Coupled-Cavity Travelling Wave tube (CC-TWT) Authors: Raju, R. S.; Sharma, S. K.; Srivastava, V.; Sharma, A.K.; Gupta, S. S.; Joshi, L. M.; Rao, R.R.; Singh, Virendra; Sain, G. R.; Faruki, H.; Manasi; Joshi, S. N. Abstract: Radar transmitters. The tube has four main parts: 1. Electron gun; 2. Collector; 3. Coupled cavity slow wave structure; and 4. I/P and O/P waveguide coupler with rf window. Electron gun produces electron beam, CCSWS reduces the velocity of rf signal equal to the velocity of electron beam. The interaction takes place between electronbeam and rf signal. Electron bunches are formed if signal is amplified. CC-TWT has been designed by CEERI and its development work is in progress. Various subassemblies like Electron gun, CCSWS, I/P and O/P waveguide couplers with rf windows and collectors have been developed. After testing these subassemblies were integrated to make complete CC-TWT. Page(s): 95-98

Diversity of Scendesmus species in Tola Lake of Mahoba (UP)

Sat, 01 Dec 2001 00:00:00 GMT

Title: Diversity of Scendesmus species in Tola Lake of Mahoba (UP) Authors: Diwedi, Sanjay; Toppo, Kiran; Sushila, M. R. Abstract: Samples of algae were collected for the study of Scendesmus species in Tola Lake of Mahoba (UP). Among the lot 17 Scendesmus species were detected. In the present paper Scendesmus has been classified based on cell structure etc. Page(s): 92-94

Embryo Abnormality in Relation to Seed Sterility in Exotic Pine Species of Kumaon Himalayan Region

Sat, 01 Dec 2001 00:00:00 GMT

Title: Embryo Abnormality in Relation to Seed Sterility in Exotic Pine Species of Kumaon Himalayan Region Authors: Sahai, Kanak Abstract: Six exotic species were selected for the present study. Pre and post fertilization stages of embryo showed that in Pinus patula. P taeda and P elliottii degeneration was started mainly at the early stage of embryo development during cell division. In P. thunbergii and P. greggii, abnormal embryo was developed by uncontrolled division, which was unable to survive for a long period. In P. echinata and P. palula dead endosperm was found before fertilization and in some places it had been damaged during embryo development. Endosperm is a food reservoir for the embryo, hence absence of food supply caused death of embryo which ultimately produced sterile seeds. Abnormal archegonia were also seen in P. patula during the study which might be responsible for seed sterility. Page(s): 89-91

Piriformospora Indica - An Unique Plant Growth Promoting Fungus

Sat, 01 Dec 2001 00:00:00 GMT

Title: Piriformospora Indica - An Unique Plant Growth Promoting Fungus Authors: Singh, Archana; Verma, A.; Tiwari, S. K.; Johri, J. K. Abstract: Piriformospora indica is a novel plant growth promoting root endophyte. It is an unique fungus which helps the plant in obtaining the nutrients for their growth in addition to the normal availability. This fungi can grow easily in artificial media and behaves like a mycorrhiza. Since the fungus can grow well in artificial media it can be multiplied easily and as such can assist the plant growth promotion. It colonizes the roots of many important crops like Maize (Zea mays L.), Tobacco (Nicotiana tabacum L.), Paddy (Oryza sativa L.), Sorghum (Sorghum vulgare L.), Wheat (Triticum aestivum L.), Soybean (Glycine max L. Merr.), Gram (Cicer arietinum L.), Artimissia (Artemissia annua L.), Brahmi (Bacopa moniera L. Wett.). The fungus helps in phosphate sublization and also in mobilization of nutrients. It has been mass multiply in by furmantion technique and so also on solid media. The fungus change the future of agriculture and can be a best source of biofertilizer. Page(s): 84-88