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Karunakar, G.
- Slot Coupled H-plane Tee Junction Analysis
Authors
1 Department of ECE, GIT, GITAM University, Visakhapatnam, IN
Source
Indian Journal of Science and Technology, Vol 4, No 8 (2011), Pagination: 957-959Abstract
This paper deals with Slot coupled H-plane tee junction analysis through longitudinal slot in the narrow wall of primary guide. In this analysis wave guides is determined from self-reaction and discontinuity in modal current. Variation of coupling and impedance loading as the primary guide are determined from the equivalent parameters. In the present paper, the equivalent circuit parameter for a long axial shunt slot in the common narrow wall is determined from self reaction and discontinuity in modal current. Coupling and input VSWR are determined from the even and odd mode analysis. Variation of coupling, input VSWR, and impedance loading on the primary guide as a function of slot length are determined.Keywords
Slot Coupled H-plane, Tee JunctionFull Text
References
- Marcuvitz N (1951) Waveguide Handbook. McGraw-Hill, NY.
- Marcuvitz N and Schwinger J (1951) On the representation of electric and magnetic fields produced by currents and discontinuities in waveguides, J. Appl. Phys. 22. 806-819.
- Oliner AA (1957) The impedance properties of narrow– radiating slots in the broad face of rectangular waveguide, part-I. IEEE Trans. Antennas & Propagation. AP-5 (1), 5- 20.
- Pandharipande VM and Das BN (1979a) Slot coupled tee junction i. rectangular guide E-plane. IEEE Trans. Microwave Theory Tech. pp: 65-69.
- Pandharipande VM and Das BN (1979b) Equivalent circuit of a narrow-wall waveguide slot coupler. IEEE Trans. Microwave theory Tech. MTT-27 (9).
- Prasad SM and Das BN (1973) Studies on waveguide fed slot antennas. Proc. Inst. Elect. Eng. 120 (5), 539-540.
- 3D Configuration of Kimberlite Bodies, Indravati Basinal Area, Bastar District, Chhattisgarh
Authors
1 GSI, Marine Wing, DK 6, Salt Lake, Kolkata - 91, IN
2 GSI, seminary Hills, Nagpur, IN
3 GSI, CGD, 27 JLN Road, Kolkata - 16, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 65, No 6 (2005), Pagination: 679-688Abstract
Gravity-Magnetic mapping and resistivity sounding have been conducted in a grid pattern of 50 m × 100 m and 200 m × 200 m respectively over one square km area between Tokapal and Duganpal villages on Jagdalpur-Gidam road about 18-20 km from Jagdaipur township. The objective has been to map the eastern and the northern extension of an already known kimberlite sill in the area which is exposed in a pit and intersected in some drill holes at shallow depth to the west of the area surveyed.The Bouguer anomaly (BA) map reveals a near circular peak marginal high of + 0.5 mGal around 0/N100 station over the background value of -59 mGaI in the area surrounded by an envelope of +0.3 mGal, almost in a N-S disposition between the traverses W350 and E100 stretching from the northern end down to S400 grid. Another such N-S feature, somewhat subdued (+0.3m Gal), is recorded in the BA map, in the northeastern part of the area bounded by traverses E200 and E400 and the base line. It is interesting to note that this sill like body is exposed around station E200/S300 where no BA high is detected. However, in the magnetic (VF) map, this sill body is picked up as a dipolar anomaly. Joining the axes of the dipolar lows and highs, the magnetic kimberlite body is yet again resolved into two near circular bodies as recorded in the gravity map. A gap in the continuity of the kimberlite sill around E200 is also indicated.
3D Euler's deconvolution solutions arrived from both the gravity and the magnetic (VF) data assuming a sill type body have been extremely useful in demarcating the geometry of the causative body at three different depth levels.The resistivity in a grid pattern shows the evidence of buried kimberlite in the area characterized by a marginal resistivity high (30-130 0hm.m). A 3D subsurface map of the kimberlite sill using ROCK WORKS has been prepared from the resistivity data.
Several 2-D G-sMe ctions have also been presented constraining these from the results of resistivity survey. Such sections will immensely help in targetting future drill holes in the area. The 3D Euler's deconvolution solutions and the 3-D configuration of the Kimberlite body have lent the third dimension in prospecting the covered kimberlites through geophysical mapping.
Keywords
Kimberlites, 3D Configuration, Gravity-Magnetic Mapping, Resistivity, Indravati Basin, Bastar District, Chhattisgarh.
- The March 1999 Chamoli Earthquake in the Garhwal Himalaya: Aftershock Characteristics and Tectonic Structure
Authors
1 Gelogical Survey of India, Central Geophysics Division, 27, J.N. Road, Kolkata - 70001 6, IN
2 Geological Survey of India, Northern Region, Lucknow - 226 024, IN
3 Geological Survey of India, Eastern Region, Salt Lake, Kolkata - 700 094, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 62, No 5 (2003), Pagination: 558-580Abstract
The aftershock sequence of the Chamoli earthquake (mb 6.3) of March 28, 1999 provides an opportunity to study the aftershock characteristics and the seisrnotectonic structure in the Garhwal Himalaya. Detailed analysis of the spatial variation, the frequency-magnitude distribution (b-value), the activity decay-rate (p-value) and fault-plane solutions of the aftershocks throw new light on the aftershock characteristics and seismotectonics of the region. The observations suggest that the aftershock generating process and the b- and p- values changed with time, space and magnitude-ranges. The main shock occurred on the Basement Thrust by a thrust-fault mechanism. The aftershocks, on the other hand, are triggered by the seismogenic faults to the south of the Main Central Thrust (MCT) by thrust as well as by strike-slip faulting, and all the events occurred above the plane of detachment.Keywords
Main shock, Aftershocks, Seismicity, Fault-Plane Solution, Seismotectonics, Chamoli, Garhwal Himalaya.- Interaction between Entomopathogenic Nematodes and Granulosis Viruses of Chilo infuscatellus Snellen and Chilo sacchariphagus Indicus (Kapur)
Authors
1 Maduranthakam Co-op, Sugar Mills Ltd., Padalam 603 308, Kancheepuram Dist., Tamil Nadu, IN
2 Section of Entomology, Sugarcane Breeding Institute, Coimbatore 641007, Tamil Nadu, IN
Source
Journal of Biological Control, Vol 16, No 2 (2002), Pagination: 153-156Abstract
Steinernema feltiae Filipjev, S. glaseri Steiner and Heterorhabitis indica (Poinar, Karunakar, David) developed and reproduced in sugarcane shoot borer, Chilo infuscatellus Snellen and Chilo sacchariphagus indicus (Kapur) larvae infected with granuloviruses (GV). The mean percent infectivity of the three nematode species showed no significant difference among the diseased and healthy larvae of both shoot and internode borers. The multiplication of dauer juveniles was significantly higher in healthy larvae of C. infuscatellus and C. sacchariphagus indicus compared to GV infected larvae.Keywords
Granuloviruses, Heterorhabditis indica, Interactive Effects, Steinernema feltiae, S. glaseri.Full Text
- Influence of Storage Temperature, Population Density and Duration of Storage on the Survival of Three Species of Entomopathogenic Nematodes
Authors
1 Section of Entomology, Sugarcane Breeding Institute, Coimbatore 641007, Tamil Nadu, IN
Source
Journal of Biological Control, Vol 15, No 2 (2001), Pagination: 183-188Abstract
Among the five different temperatures tested for storage of infective juveniles (Ijs). survival of Steinernema feltiae Filipjev and S. glaseri Steiner was higher at 7.5°C, while the survival of Heterorhabditis indica (Poinar, Karunakar and David) was higher at 10°C. All the three species of nematodes showed higher percentage of survival when stored at 250 IJs per ml compared to 500 and 1000 Us per ml. A negative correlation was observed between duration of storage and per cent survival in S. feltiae (r = -0.9831**). S. glaseri (r = -0.9847**) and H. indica (r = -0.9437**). Based on the results of the study, the best combination of temperature, population density and duration of storage for the entomopathogenic nematodes was 7.5°C, 250 IJs perml and 120 days, respectively for S. feltiae, 7.5°C, 250 IJs per ml and 90 days for S. glaseri and 10°C, 250 IJs per ml and 90 days for H. indica.Keywords
Heterorhabditis indica, Population Density, Steinernema feltiae, S. glaseri, Storage.Full Text
- Biology of Heterorhabditis indicus Poinar, Karunakar & David, 1992
Authors
1 Kallakurichi Co-op. Sugar Mills Ltd, Vadamathur Village, Kanji, IN
2 Sugarcane Breeding Institute, Coimbatore, 641 007, IN
3 University of California, Berkeley, California - 94720, US
Source
Journal of Biological Control, Vol 7, No 1 (1993), Pagination: 24-28Abstract
The life cycle of Heterorhabditis indicus Poinar, Karunakar & David, 1992 closely resembles that of other heterorhabditids. It has two cycles - a hermaphroditic cycle, one with an oviparous generation with a complete set of four juvenile stages and another amphimictic generation with four juvenile stages. These hermaphroditic and oviparous generations are completed in 11-12 days in Galleria mellonella (L.) (Gallerriidae:Lepldoptera)at 24°C.
Keywords
Heterornabditis indicus, Biology, Galleria mellonella.Full Text
- Influence of Dosage of Steinernema carpocapsae (Weitser) S. glaseri Steiner and Heterorbabditis indicus (Poinar, Karuuakar and David) on Mortality of the Host and Multiplication of Infective Juveniles in Sugarcane Internode Borer,
Authors
1 Sugarcane Breeding Institute, Coimbatore - 641 007, IN
Source
Journal of Biological Control, Vol 6, No 1 (1992), Pagination: 26-28Abstract
Steinernema carpocapsae (Welser), S. glaseri (Steiner) and Heterorhabditis indicus (Polnar, Karunakar and David) at an Inoculum level of 40 infective juveniles (IJ) per Illrva caused 97.5 - 100 per cent mortality of Chilo Sacchariphagus indicus (Kapur) larvae and the morfality decreased with decrease in dosage levels. There was no significant difference in the mortality caused by the three species of nematodes. The multiplilcation of infective juveniles (IJ) per unit body weight of the host was higher in H. indicus than in S. capcapsae and S. glaseri. The dosage level of 20 IJ/larva yielded significantly high nematode multiplication in S. glaseri (37,335.8 IJ/larva) and H. indicus (2,10,283.3 IJ/larva) while S. carpocapsae multiplied to the maximum at a dosage of 10 IJ/larva (1,35,894.3 IJ).Keywords
Dosage-Mortality, Multiplication, Steinernema glaseri, S. carpocapsae, Heterorhabditis indicus, Chilo sacchariphagus indicus.Full Text