006238   Chandra Hari K (IRS, ONGC, Ahmedabad-380 005) : Computation of the true moon by madhava of sangama-grama. Indian J Hist Sci 2003, 38(1), 231-53.

Sangama-grama Madhava (1400 AD) was a great astronomer and mathematician of his times. A number of his works have failed to survive but in the ones that survived and the mathematical contributions that have come to light through the quotations in later works. The paper is a study on his astronomica treatises, Venvaroha and Sphutacandrapti, which contain the true longitudes of Moon derived by Madhava, in the light of modern astronomical computations. Madhava's simplest techniques for computing true moon in his Venvaroha or (ascending the Bamboo) based on the anomalistic revolutions of Moon is illustrated with examples and the results have been compared with the computer-derived modern longitudes for Madhava's epoch as well as for present times.

18 tables

006237   Chandra Hari K (NO, , B-204, Parth Avenue, Ahmedabad-5, Gujarat) : Eclipse observations of Paramesvara, the 14-15 century astronomer of Kerala. Indian J Hist Sci 2003, 38(1), 43-57.

Attempts to bring to light a glorious chapter of astronomical observations in India, of which records have survived. Paramesvara had his advent at the middle of the 14th century and enriched the Kerala astronomical tradition through precise observations and astronomical experimentation. Paramesvara's eclipse observations extending over a period of five decades have been examined here in the light of modern astronomical algorithms. Sun and Moon, mean as well as true longitudes, of both Paramesvara and his disciple Nilakantha precisely agree with those determined using the most modern algorithms. Also the paper gives the correct interpretation of the verse IV.9 of Goladipika that specifies the location of Paramesvara's village Alattur. Paramesvara's village near Palghat cannot be on the west of the meridian of Ujjain as is usually interpreted. alattur is fact is 18 yojanas east of the meridian of Ujjain.

11 ref

006236   Bag A K (Indian National Sci Academy, , Bahadur Shah Zafar Marg, New Delhi-110 002) : A note on the Ahargana and the weekdays as per modern suryasiddhanta. Indian J Hist Sci 2003, 38(1), 39-42.

Aims to re-examine the correctness of JD numbers for Kali, Varahamihira and Brahmagupta epochs.

^ssc4 ref

006235   Bag A K (Indian Natn Sci Academy, , Bahadur Shah Zafar Marg, New Delhi-110 002) : Luni-solar calendar, Kali ahargana and Julian days. Indian J Hist Sci 2003, 38(1), 17-37.

Computes the elements of luni-solar calendar, like saura months, lunar months, injercalary months, omitted tithis, and gives general rules for computing ahargana from different epochs. The later ahargana rules agree very well with that of the Kali ahargana which started counting of days from the Kali epoch. The use of Kali ahargana (KA) for recording time of important events was quite popular and became the part of Indis's history and culture. Since ahargana is nothing but collection of civil days, it has corresponding agreement with number of Julian days, and as such the system of conversion from one to another has also been included and clarified with the help of tables and examples. This will show that the popularity of KA was based on a strong mathematical foundation, even though the major objective of KA rule was to calculate the mean planetary positions.

3 tables, 41 ref

006234   Abraham G;Cornelius J S (NO, , Plot 1520, H-Block, 12th Main Road, Anna Nagar, Chennai-600 040) : Observational astronomy. Indian J Hist Sci 2003, 38(3), 367-76.

Following up the work of Roger Billard, the mean daily motions of the sun, moon and planets in the theories of Ptolemy, Aryabhata, Lalla and Nilakantha Somayaji are calculated, and compared with the results of modern formulae.

3 illus, 2 tables, 8 ref

003090    (ESA RSSD, European Space Agency, , ESTEC/SCISR Postbag 299, 2200 AG Noordwijk, The Netherlands, Email: Bernard.Foing@esa.int) : The case for the first Indian robotic mission to the moon. Curr Sci 2004, 87(8), 1061-5.

The Moon is a key to planetary science and exploration. The Indian space program has the capability to design, build and launch its own satellites, with its successful PSLV and GSLV rockets. Also, ISRO has developed science satellites and instrumentation. In this context, the Indian science community and ISRO have discussed and studied in depth the possibility of a lunar mission (Chandrayaan-1), with an instrumented spacecraft through an Indian launcher. The scientific value of the mission the its timeliness, challenges and scope for international cooperation has been discussed.

27 ref

002049   Vamsi Kiran D;Srinivasa Rao C;Ramakrishnan R; Gupta P (Computer Sci and Engng Dep, Indian Inst of Technol Kanpur, Kanpur-208 016) : Efficient encoding and decoding algorithms for distributed resampling. J Indian Soc Remote Sens 2004, 32(3), 269-86.

Algorithms for compressing floating point data which is encountered whle performing resampling algorithm for rectifying geometric distortions on the images transmitted by the remote sensing satellite on a distributed computing environment have been discussed. Two efficient algorithms for encoding and decoding floating point data compression, 3-byte packing and 3-byte + 2-bit packing have been proposed. Both algorithms are tested to exceute resampling algorithm on radiometrically corrected for IRS-LISS-III 4 bands data on a distributed system. First algorithm compresses 4-byte floating point data to 3-byte obtaining 25% compression while later one compresses 4-byte floating point data to 3-byte + 2-bit achieving about 18.75% compression. The computational time is reduced by 22% as compared to the distributed resampling algorithms without compression. Further it is found that in lossy compression algorithm only 220 pixels out of 37.4 MB pixels have utmost one Gray count difference, which will not pose any issues for digital classification or any other methods that will be employed in the corrected image by Image Analysts.

7 illus, 5 tables, 10 ref

002048   Thanikachalam M;Ramachandran S (Inst of Ocean Management, Anna Univ, Chennai-600 025) : Shoreline and coral reef ecosystem changes in Gulf of Mannar, Southeast coast of India. J Indian Soc Remote Sens 2003, 31(3), 157-73.

Changes in shoreline, coral reef and seafloor have been mapped using remote sensing satellite data of IRS LISS-III (1998), IRS LISS-II (1988), Survey of India Topographic sheet (1969), Naval Hydrographic Chart (NHO) 1975 and bathymetry data (1999) with ARC-INFO and ARC-VIEW GIS. The analysis of multi-date shoreline maps showed that 4.34 and 23.49 km² of the mainland coast and 4.14 and 3.31 km² areas of island coast have been eroded and accreted, respectively, in the Gulf of Mannar. The analysis of multi-date coral reef maps showed that 25.52 km² of reef area and 2.16 km² of reef vegetation in Gulf of Mannar have been lost over a period of ten years. The analysis of multi-date bathymetry data indicates that the depth of seafloor has decreased along the coast and around the islands in the study area. The average reduction of depth in seafloor has been estimated as 0.51m over a period of twenty four years. The increased suspended sediment concentration due to coastal and island erosion, and raised reef due to emerging of coast by tectonic movement are responsible for coral reef degradation in the Gulf of Mannar. Validation by ground truth has confirmed these results.

8 illus, 3 tables, 43 ref

002047   Suresh M;Sudhakar S;Tiwri K N;Chowdary V M (Agric and Food Engng Dep, Indian Inst of Technol, Kharagpur-721 302) : Prioritization of watersheds using morphometric parameters and assessment of surface water potential using remote sensing. J Indian Soc Remote Sens 2004, 32(3), 249-59.

In the present study, prioritization of sub-watersheds was carried out on the basis of sediment production rate. Further, basic hydrologic information such as peak rate of runoff and annual surface water potential were also assessed for the study of watersheds and these are essential requisites for effective watershed management. The 10 sub watersheds of Tarai development project area are selected for the present study. Morphometric parameters pertaining to study area are used in the estimation of sediment production rate. The sediment production rate in the study area varies between 2.45 to 11.0 ha-m/100 km²/year. The remote sensing data has been utilized for generating land use/land cover data which is an essential prerequisite for land and water resource planning and development. The remote sensing data can especially play significant role in collection of real time information from remote areas of river basins for generation of parameters required for hydrologic modeling.

2 illus, 5 tables, 16 ref

002046   Soni A K;Loveson V J (Central Mining Res Inst, Reg Centre, , Seminary Hills, Nagpur-440 006) : Land damage assessment - a case study. J Indian Soc Remote Sens 2003, 31(3), 175-86.

Land damage assessment and change detection analysis with reference to a mineral bearing zone in Manjhi, Manuni and Churan valleys. The area is located in environmentally sensitive and fragile region of Himalaya and constitutes of nearly 400 small-scale mines of slate, which were operative since last one hundred years and are stopped by court of law since 1995 on account of environment deterioration. The status of land degradation has been studied using IRS-1B satellite data of 1988, 1992 and 1995. The geocoded data on 1:50,000 scale has been interpreted and an increase in land degradation status was noticed. Finally, the management strategy for arresting the further land damage in a broader perspective is suggested.

^ccr7 illus, 3 tables, 17 ref

002045   Singh I J;Moharir S (Indian Inst of Remote Sensing, NRSA, Dehradun-248 001) : Forest management using remote sensing and GIS in Barbatpur range, Betul forest division. J Indian Soc Remote Sens 2003, 31(3), 149-56.

Forest management is defined as the practical application of the scientific, technical and economic principles of forestry. Working plan is the key document to accomplish well-defined descriptive, prescriptive activities of forest management. The role of remote sensing and GIS in forest management has been investigated. Qualitative and quantitative analysis have been made (forest cover type with overall accuracy 83.17%; average volume per ha 66.2 m³; total growing stock 119217.95 m³ and total number of bamboo culms 9228416). Suitable sites for a afforestation and joint forest management have been identified. The prescriptions for various forest stands in context with management working circles have also been made.

4 illus, 2 tables, 14 ref

002044   Selvavinayagam K;Surendran A;Ramachandran S (Inst for Ocean Management, Anna Univ, Chennai-600 025) : Quantitative study on chlorophyll using IRS-P4 OCM data of Titicorin coastal waters. J Indian Soc Remote Sens 2003, 31(3), 227-35.

Quantification of chlorophyll using IRS-P4 OCM data was attempted. OCM-DAS software developed by Space Applications Centre, Ahmedabad was used in data analysis. The results showed considerable variations in nearshore waters due to interference from yellow substance and suspended sediments. However, in offshore areas the measurements showed good correlations. The r values are 0.663 for nearshore waters and 0.892 for offshore waters.

3 illus, 4 tables, 27 ref

002043   Murthy K S R;Amminedu E;Rao V V (Geo-Engng Dep, Coll of Engng, Andhra Univ, Visakhapatnam-530 003) : Integration of thematic maps through GIS for identification of groundwater potential zones. J Indian Soc Remote Sens 2003, 31(3), 197-210.

The remote sensing data combined with Geographical Information system (GIS) technique has been proved to be very efficient in identification of groundwater potential of any area. IRS 1A, LISS II data has been used to identify the groundwater potential zones by integrating various thematic maps generated on 1:50,00 scale. These maps are integrated after assigning weight factors to the identified features in each thematic map depending upon their infiltration capacities and the groundwater potential zones in Bhamini mandal (developmental block) of Srikakulam district, Andhra Pradesh are demarcated. The area of investigation has been classified into seven groundwater potential zones. Results show that integration of all attributes provides more accurate results in groundwater potential zones identification.

8 illus, 2 tables, 15 ref

002042   Mohanty C;Baral D J;Malik J N (Civil Engng Dep, Indian Inst of Technol, Kanpur-208 016) : Use of satellite data for tectonic interpretation, NW Himalaya. J Indian Soc Remote Sens 2004, 32(3), 241-7.

5 illus, 9 ref

002041   Mahtab A;Sridhar V N;Ghosh R (Remote Sensing Applications and Image Processing Area (RESIPA), Space, Indian Space Res Organ (ISRO), Ahmedabad-380 015) : Comparison of two forest types using adeos 1-polder data over west coast of India. J Indian Soc Remote Sens 2004, 32(3), 261-8.

Parametric kernel-based models for Bi-directional Reflectance Distribution Function (BRDF) or vegetated land surfaces attempt to describe the BRDF as a linear superposition of a set of kernels describing basic angular shapes. The kernels and associated model coefficients are derived as approximations to the underlying theories of radiative transfer as well as geometric-optical scattering within vegetation canopies. In the present study, five kernels viz. Ross-Thick, Li-Sparse, Ross-Thin, Li-Dense and Roujean geometric-optical (GO) kernels along with a purely empirical model were examined for their suitability in describing the angular characteristics of two forest types (semi-evergreen and deciduous) during November 1996-March 1997 using ADEOS-1 POLDER data. The statistically significant kernels and their combinations with respect to red and NIR (near infra-red) wavelength were determined using correlation analysis. Atmospherically corrected POLDER measured reflectances at red and NIR wavelengths were regressed with different kernels and their combinations. It is found that the best fitting volume and GO kernel combinations depend on forest type, wavelength and data.

2 illus, 3 tables, 16 ref

002040   Kunwar P;Kachhwah T S (Forest Resources and Ecology Div, Remote Sensing Application Centre, Lucknow-226 021) : Spatial distribution of area affected by forest fire in Uttaranchal using remote sensing and GIS techniques. J Indian Soc Remote Sens 2003, 31(3), 145-8.

1 illus, 1 table, 12 ref

002039   Kasturirangan K (National Inst of Advanced Studies, Indian Inst of Sci Campus, Bangalore-560 012) : Science and technology of imaging from space. Curr Sci 2004, 87(5), 584-601.

Imaging techniques from space, started mainly as a military reconnaissance tool, have come a long way from its early concepts to meet the present day needs of pvoviding a precise metrology of the Earth processes and its features. The first part of the paper deals with the basic concepts of imaging from space. In this, the energy source available and the effect of atmosphere on the radiation are elaborated. Also the signatures of objects for identification and their characteristics in spatial and spectral domain are briefly touched upon. The second part of the paper deals with the challenges in realizing a satellite with limited volume and weight constraints by giving examples of very innovative approaches in the design of the optical systems for telescopes. The challenges associated with high resolution imaging and resulting high amount of data handling through appropriate data compression techniques are highlighted. The work presented here has been primarily carried out at the Indian Space Research Organization (ISRO). The paper concludes with an assessment of the futuristic direction that include improved algorithms for parameter retrieval and improved classification accuracies, improved models for atmospheric correction, new approach in artificial intelligence and expert systems for feature based classfication, improved data compression techniques, ultra-light weight mirrors and adaptive optics, optical materials and detector arrays with built-in read out in the infrared region.

23 illus, 17 ref

002038   Himabindu D;Ramadas S G (Center for Exploration Geophysics, Geophys Dep, Osmania Univ, Hyderabad-500 007) : Structural inferences from satellite image in and around Gadag, in the Dharwar craton. J Indian Soc Remote Sens 2003, 31(3), 219-25.

The geological interest of the Dharwar craton in the Precambrian Indian peninsular shield stems from its complexity. A satellite image (IRS-ID-LISS-III) of an area of approximately 12,000 sq km corresponding to the region in and around Gadag in the Dharwar craton, was analyzed to determine the geological/structural configuration of the region. The disposition of schist belts, shear zones, and various faults and other lineaments in the region were delineated. The findings are significant in view of the paucity of structural data in the region and form a geo-structural data base based on which ground surveys can be planned.

2 illus, 12 ref

002037   Chauhan P S;Porwal M C;Sharma L;Negi J D (Indian Inst of Remote Sensing (IIRS), , Dehradun-248 001) : Change detection in sal forest in Dehradun forest division using remote sensing and geographical information system. J Indian Soc Remote Sens 2003, 31(3), 211-8.

The review of study site have revealed the change in vegetation cover of Sal Dense to Sal Medium and Sal Open in 6 forest Mosaics owing to biotic and abiotic conditions prevailing in the specific areas. analysis carried out using thematic map derived from aerial photograph of 1976 and satellite data of IRS 1C LISS III False Colour Composite (FCC) of March 1999 revealed the cause for change in forest density classes. Deforestation, encroachment and agriculture have been identified as the underlying causes, which have affected some specific locations to a marked extent. There has been a progressive and remarkable change among vegetation classes from 1976 to 1999. It is evident from forest types and density map that Sal density has significantly reduced from Sal Dense 65.61% in 1976 to Sal Dense 11.12% in the year 1999 followed by Sal Open 11.18 and Sal Medium 18.24%. The overall change has been estimated to be 42.11% of the total forested area.

5 illus, 15 ref

002036   Chari K B;Abbasi S A (Centre for Pollution Control and Energy Technology, Pondicherry University, Kalapet, Pondicherry-605 014) : Assessment of impact of land use changes on the plankton community of a shallow fresh water lake in south India by GIS and remote sensing. Chem envir Res 2003, 12(1-2), 93-112.

Efforts were made to delineate the land-use and land-cover of Oussudu catchment (Pondicherry, India) using remote sensing, GIS and ground-truth survey and associate the likely implications of land-use on the plankton community during the years 1997, 1999 and 2000. Quantitative and qualitative characteristics of the plankton population were investigated during 1999 and 2000 and compares with an earlier unpublished study of the authors done in 1997. The plankton communities were compared using various parameters such as: changes in the species composition, number of species, and indicator species; changes in the structure of plankton community through changes in the diversity indices and plankton quotients and the role of land-use and lake management in contributing to the above changes.

11 illus, 5 tables, 38 ref

000017   Chandra S (School of Physical sciences, S.R.T.M. University, Nanded 431 606) : Radiative excitation of CS molecules in atmosphere of a star. Indian J Phys-Pt B 2003, 77(6), 617-20.

Investiged radiative excitation of CS molecules in atmosphere of a carbon star. Besides those of the observed lines of CS molecule, intensities of some other lines, in the ground v=O as well as vibrationally excited v = 1 states, are computed. Intensities of other lines are found comparable to those of the observed ones, in the corresponding vibrational state, and therefore, those lines are probable candidates for their detection. The lines in the vibrationally excited state, as well as between higher rotational levels in the ground vibrational state, are found to have tendency of their formation in the regions close to the photosphere of the star, whereas the reverse has been found for the lines between lower rotational levels in the ground vibrational state. It is found that lines in the vibrationally excited state cannot be generated, even in a high temperature region, unless external unfrared radiation field is present.

2 illus, 1 table, 10 ref

014432   Roxy M S;Sumithranand V B;Renuka G (Physics Dep, Kerala Univ, Kariavattom, Thiruvananthapuram-695 581, Email: roxyms@gmail.com) : Analysis of air temperature at astronomical observatory, Thiruvananthapuram using Fourier techniques. Ultra Scient phys Sci 2010, 22(2), 279-82.

Continuous observation data collected over the year 2008 and 2009 at Astronomical Observatory, Thiruvananthapuram in south Kerala (76° 59' E longitude and 8° 30' N latitude) have been subjected to a series of Fourier analysis. The resulting coefficients give an objective measure of the phase and amplitude variations of the annual air temperature cycles. The first five harmonics explains about 99.99% of the variation. The original data is reconstructed from the Fourier coefficients by plotting all the five harmonics and then adding the resulting curves.

1 illus, 1 table, 7 ref

013224   Toqvi Z A;Saxena M;Saha L M (Mathematics Dep, Jamia Millia Islamia, Okhla, New Delhi-110 023) : Chaotic motion of an ellipsoidal satellite. Proc Natn Acad Sci India-Sect A 2009, 79(PtIII), 259-66.

Evolutionary behavior of various satellites in solar system has been studied analytically and numerically by taking into account the appropriate data and the equations of motion. The equation of motion is that of the spin-orbit type containing effects of solar radiation, tidal and some other perturbing forces. Numerical results show that a number of satellites of various planets move chaotically or irregularly. Some numerical results indicate significant and interesting results on evolutionary behaviour. The study further reveals the fact that our solar system is not the paradigm of order and regularity.

7 illus 12 ref

012118   Chakrabarti S K;Mandal S K;Sasmal S;Bhowmick D;Choudhury A K;Patra N N (NO, S N Bose National Centre for Basic Sciences, JD-Block, Sector-III, Salt Lake, Kolkata-700 098, Email: chakraba@boson.bose.res.in) : First VLF detections of ionospheric disturbances due to soft gamma ray repeater SGR J1550-5418 and gamma ray burst GRB 090424. Indian J Phys 2010, 84(11), 1461-6.

Presents the first report of the detection of sudden ionospheric disturbances (SIDs) due to a Soft Gamma Ray Repeater (SGR) SGR J1550-5418 and a Gamma Ray Burst (GRB) GRB 090424. These detections were made with receiving stations of Indian Centre for Space Physics which were monitoring Very Low Frequency signals (VLFs) from the VTX transmitter located at the southern tip of Indian sub-continent. These positive detections add to the list of a handful of similar detections of other GRBs and SGRs throughout the world.

4 illus, 22 ref

008886   Somoye E O (Physics Dep, Lagos State Univ, Legos, Nigeria, Email: femi2000somoye@yahoo.com) : Diurnal and seasonal variation of fading rates of E- and F- region echoes during IGY and IQSY at the equatorial station of Ibadan. Indian J Radio Space Phys 2010, 39(4), 194-202.

Fading rates of E- and F-region echoes observed at Ibadan (7.4°N, 3.9°E, 6°S dip) during the International Geophysical Year (IGY) 1958 and the International Quiet Year of the Sun (IQSY) 1964 are investigated for diurnal and seasonal variations. The fading rates of E- and F-region echoes are found to be of the same order of magnitude during the IQSY. However, the same is not true during IGY indicating that fading of F-region echoes is dependent on solar activity while that of E-region echoes is not as fading rate of E-region echoes are about the same during both epochs. The fading rate is found to be maximum at noon and minimum at sunrise and sunset for E-region echoes during both epochs and for F-region echoes during IQSY. During IGY, fading rate is maximum at noon; and minimum at sunrise and 2000 hrs LT (i.e. post sunset) at both epochs and for the two regions about same times of reversal of F-region East-West (EW) and ExB vertical drift during solar maximum. The maximum at noon appears to be due to: (i) continuous daytime rise in hmF2 which enhances irregularities and (ii) spread F irregularities generated by sudden increase in ExB plasma uplift not seen by the close-spaced antenna technique used in the present study. F-region fading rate is maximum during December solstice while E-region fading rates show no seasonal variation.

7 illus, 42 ref

008885   Singh V;Singh B (Physics Dep, Communication Engineering Dep, Faculty of Engineering and Technology,, Bichpuri, Arga-283 105, Email: vikram_sks@rediffmail.com) : Scattering of VLF signals from localized perturbations in the lower ionosphere. Indian J Radio Space Phys 2010, 39(3), 144-9.

A wave-slab interaction model has been used to study the'scattering of very low frequency (VLF) ground transmitter signals from localized enhancements of ionization in the lower ionosphere caused by transient luminous events (TLEs) such as sprites. The variation of reflection coefficients has been studied for a fixed frequency VLF transmitter signal of frequency 19.8 kHz (NWC, Australia) monitored at Agra for different slab thicknesses, incident angles, and enhancement factors. The results show that sufficient strength of the reflected signals is obtained for a slab thickness of 3 km, enhancement factor between 2.5 and 3, and incident angle around 75°C. These results explain satisfactorily the VLF amplitude and phase anomalies in sub-ionospheric VLF transmitter signals recorded at Agra station which are interpreted as caused by transient luminous events.

5 illus, 19 ref

008884   Saxena E;Yadav R;Adarsh Kumar;Rai J (Fculty of Science, Meerut College, Meerut-250 002, Email: adarsh_phy@yahoo.co.in ) : Measurement of atmospheric aerosols during monsoon and winter seasons at Roorkee, India. Indian J Radio Space Phys 2010, 39(4), 208-17.

Measurement of aerosol concentration has been carried out in view of some meteorological parameters like wind speed, temperature, relative humidity and rainfall during south-east (SE) monsoon (June-September 2006) and winter (November 2006-February 2007) at Roorkee, India. The measurements were done with the help of laser beam scatterometer for wide range of aerosols (0.05-3.0 urn). The study reveals the fact that the number density of aerosols is very much affected by meteorological parameters. The aerosol concentration was minimum in August, September and November 2006 and remained around maximum during June-July 2006 and January-February 2007. During monsoon period, the rain plays important role in characterizing aerosol density. The aerosol concentration and size were found to be decreased during September 2006 although relative humidity was found to be very high due to scavenging of aerosol particles.

6 illus, 20 ref

008883   Satsangi A;Singla V;Lakhani A;Maharaj Kumari K (Chemistry Dep, Faculty of Science, Dayalbagh Educational Institute, Dayalbagh, Agra-282 110, Email: maharajkumari.k@rdiffmail.com) : Carbonaceous aerosols at a suburban site in indo-gangetic plain. Indian J Radio Space Phys 2010, 39(4), 218-22.

Carbonaceous aerosols are emitted by combustion sources and may influence the climate by altering the radiation balance of the atmosphere. The carbonaceous component of the atmospheric aerosols is composed of two main fractions, viz. organic carbon (OC) and black carbon (BC). BC is emitted from the incomplete combustion while OC comes from the primary emission such as traffic exhaust and biomass burning and is also formed through atmospheric chemical conversion processes. Carbonaceous aerosols were monitored at a suburban site, Dayalbagh, Agra from January to October 2009 in the present study. It was found that total suspended particulate mass (TSPM) varied from 79 to 658 μg m^-3 with an average of 273±179.9 μg m^-3. Also, daily concentrations of OC and BC ranged from 20.4 to 147.4 μg m^-3 and from 1.4 to 20.3 μg m^-3with the overall average concentrations of 60.9±40.5 μg m^-3 and 7.5±4.6 μg m^-3, respectively. OC/BC ratios indicate the emission sources of carbonaceous aerosols. When the OC/BC ratio exceeds 2.0, it indicates that carbonaceous aerosols mainly originate from secondary organic transformation. Daily average OC/BC ratio varied between 5.2 and 16.2 with an average of 8.1. To give an insight into the source contribution of OC and BC, correlation coefficient was determined. The correlation coefficient is found to be 0.79. This indicates that major fraction of OC and BC originates from a common source. Distinct monthly variation was observed in their concentrations.

3 illus, 2 tables, 31 ref

008882   Rastogi R G;Ahmed K (NO, Physical Research Laboratory, Ahmedabad-380 009) : Preliminary reverse impulse in SC (Y) at off-equatorial stations in India. Indian J Radio Space Phys 2010, 39(4), 203-7.

The storm sudden commencement (SSC) at 2345 hrs LIT on 24 September 1998, occurring at around local sunrise for Indian stations had produced uniquely two-step impulses on the H magnetogram at all stations. The amplitude AH had increased progressively from Trivandrum to Gulmarg, unlike the characteristic of the day time equatorial enhancement of SC (H). The solar wind parameters too showed abnormal variations during the period of SC. The magnetogram trace for declination (or eastward field Y) recorded a preliminary reverse impulse (PRI) close to the latitude of Sq focus at stations Gulmarg, Ujjain, Nagpur and Shillong. The PRI was absent in SC (Y) at equatorial stations Trivandrum and Pondicherry. This observations show a new complex relationship between the ionospheric dynamo and magnetospheric dawn/dusk electric field with the equatorial geomagnetic field around sunrise.

4 illus, 1 table, 15 ref

008881   Rakesh Chandra N;Yellaiah G;Vijaya Bhaskara Rao S;Geth Ram Kumar R (NO, Malla Reddy College of Engineering and Technology, Hyderabad-500 014, Email: rakeshnarwa@gmail.com) : MST radar observtions of meteor showers and trail induced irregulatities in the ionospheric E-region. Indian J Radio Space Phys 2010, 39(3), 138-43.

The Doppler spectra of amplitude variations for meteor trails and sporadic-E layers have simultaneously been recorded with MST radar at Gadanki during the active periods of Perseid, Leonid and Geminid meteor showers in 2007. The variations of the activities of the radar meteors during the shower periods and the occurrences of E-region irregularities as observed with MST radar are presented in this paper. It has been noticed that the discrete strata of sporadic-E occurring in the altitude range 95-110 km during these shower periods with maximum percentage of occurrence on the nights of peak activities of these meteor showers. The close inspection of radar meteor data reveal the generation of faint Type-1 echo during the peak active period of the Geminid shower with reduced Doppler velocities by 20% at the altitude of 91 km and are found to be imbedded in the strong Type-2. The radar data of meteors are also used to retrieve the temperatures of MLT region.

4 illus, 7 ref

008880   Ogolo E O (Physics Dep, The Federal Technology Univ, Akure, Nigeria, Email: emogolo@yahoo.com) : Evaluating the performance of some predictive models for estimating global solar radiation across varying climatic conditions in Nigeria. Indian J Radio Space Phys 2010, 39(3), 121-31.

The performance of both temperature and sunshine dependent models were evaluated for different selected tropical sites, which are situated across four different climatic zones, viz. Sahelian, Guinea Savannah, Midland and Coastal area in Nigeria. The regression constants were obtained for the first, second and third order Angstrom type [Garcia J V, Principios F'isicos de la Climatolog'ia. Ediciones UNALM (Universidad Nacional Agraria La Molina: Lima, Peru), 1994; Hargreaves G & Samani Z, Estimating potential evapotranspiration, J Irrigat Drainage Eng (USA), 108 (1982) pp 225-230] models for all the stations using the method of regression analysis. Model evaluation performance analyses were carried out to determine which model is more suitable for a given climatic condition. The results indicated that the third order Angstrom type correlations do not improve the accuracy of estimation of global radiation. In addition, the results also revealed that temperature and sunshine hour dependent models are more suitable for the simulation of global radiation in the Sahelian and Guinea Savannah climatic condition, respectively. All the models exhibited the tendency to perform suitably well in the Midland and Coastal areas. On the seasonal consideration, the sunshine hour dependent models were found more suitable for the estimation of solar global radiation across all the varying climatic conditions during the dry season. However, all the models were found suitable during the wet season except for the Sahelian where only the temperature dependent models have been found exclusively suitable.

3 illus, 5 tables, 22 ref

008879   Mallikarjun S L;Hadalgi P M (PG Dep of Studies and Research in Applied Electronics, Gulbarga Univ, Gulbgarga-585 106, Email: mslakshetty@rediffmail.com) : Single layer modified rectangular microstrip array antenna for multi band and wide band applications. Indian J Radio Space Phys 2010, 39(3), 156-62.

A four-element modified rectangular microstrip array antenna (4MRMSAA) is designed and further extended to eight element modified rectangular microstrip array antenna (8MRMSAA). A comparative study is made between the proposed antennas. The experimental results show that 4MRMSAA operates for multi band and 8MRMSAA operates for wide band with an improvement (39.34%) in impedance bandwidth. This improvement in the impedance bandwidth of 8MRMSAA is 13.80 times more as compared to single rectangular radiating element (RMSA). The experimental results of the proposed antennas have been presented in terms of impedance bandwidth, return loss, gain, half power beam width (HPBW) and cross polarization levels. These multi band and wide band antennas have applications in modern communications and radar communication systems.

7 illus, 1 table, 31 ref

008878   Kane R P (NO, Instituto Nacional de Pesquisas Espaciais INPE, C P 515, Sao Jase dos Campus, Brazil, Email: kane@dge.inpe.br) : Relationship between Dst (min) magnitudes and characteristics of ICMEs. Indian J Radio Space Phys 2010, 39(4), 177-83.

All interplanetary disturbances having shocks and directed towards the Earth are geoeffective, giving at least a storm sudden commencement (SSC) and giving Dst depressions [Dst(min)] in a wide range -10 to -500 nT, actual magnitudes roughly proportional to the magnitudes of negative Bz(min) of interplanetary magnetic field. During 1965-1996, the ejecta and shock events not accompanied with magnetic clouds (MCs) had only <126>17% intense storms [Dst(min) ≤-200 nT] but ejecta and shocks accompanied with magnetic clouds (MCs) had <126>40% intense storms. For solar cycle 23, ejecta and shocks without MCs had only <126>3% intense storms; but ejecta and shocks accompanied by MCs had 11% intense storms. Thus, events accompanied with MCs gave larger percentage of intense storms. Events related to corotating interaction regions (CIRs) led to only weak and moderate storms [Dst(min): -20 nT to -140 nT]. For cycle 23, the plots of -Bz(min) vs -Dst(min) for ejecta and shocks without MCs showed a large scatter for the ranges Bz(min) -3 to -20 nT vs Dst(min) -5 to -170 nT. Thus, analysis in this region would give confusing and uncertain results. Concentrating on intense events [Dst (min) ≤ -200 nT], the Bz(min) vs Dst(min) plot showed a correlation of only +0.77+0.12, with considerable scatter in the Dst(min) range -200 to -300 nT [for the same value of Bz(min), Dst(min) would have an uncertainty of about ± 50 nT]. The correlation did not improve when Bz(min) was substituted by the product BzV, or by cumulative negative Bz from the start to the peak of negative Bz(min).

5 illus, 25 ref

008877   Bhattacharya R;Bhoumick A;Bhattacharya A;Pal S;Bhattacharya A B (Environmental Science Dep, Kalyani Univ, Kalyani-741 235, Email: rinaenv@yahoo.co.in) : Changes in the surface UV radiation and sferics over Kalyani (West Bengal) during the solar eclipse on 22 july 2009. Indian J Radio Space Phys 2010, 39(3), 132-7.

The study was mainly confined to the investigation of the responses of downwelling solar radiation fluxes in ultraviolet wavelengths to the partial solar eclipse event on 22 July 2009 besides an investigation on sferics at 27 kHz. The measurements were done at ground-based station of Kalyani (22°58'N, 88°28'E) where the maximum solar coverage was more than 90%. The optical properties and associated meteorological parameters are simultaneously examined. During the partial solar eclipse, UV components of sunlight reaching the Earth's surface were found to decrease significantly in addition to luminosity. The surface air temperature was dropped but relative humidity was increased. A characteristic short period fading was also recorded at 27 kHz. The results have been interpreted by considering the impacts of solar eclipse on UV radiation and ionospheric propagation.

7 illus, 20 ref

008876   Bakare N O;Chukwuma V U (Physics Dep, Olabisi Onabanjo Univ, PMB 2002, Ago-Lwoye, Nigeria, Email: sesanbakare1@yahoo.com) : Relationship between Dst and solar wind conditions during intense geomagnetic storms. Indian J Radio Space Phys 2010, 39(3), 150-5.

A study of 83 geomagnetic storms during 1996-2006 has been carried out to investigate the relationship between Dst and solar wind plasma parameters during intense geomagnetic storms. The geomagnetic storms are primarily associated with two classes of drivers: the magnetic cloud and complex ejecta. It was found that magnetic cloud were drivers in 43 geomagnetic storm (<126> 51.8%) while complex ejecta were responsible for 40 geomagnetic storms (<126> 48.2%). The correlation between Dst and magnetic field B; and between Dst and Bs was 0.76 and 0.90, respectively for geomagnetic storms resulting from magnetic clouds. The correlation between Dst and B; and between Dst and Bs was 0.71 and 0.64, respectively for geomagnetic storms resulting from complex ejecta. Furthermore, it was shown that the correlation between the Dst and solar wind speed V for magnetic cloud and complex ejecta was 0.58 and 0.57, respectively. It was observed that the correlation between Dst and VBs for magnetic cloud and complex ejecta were 0.77 and 0.71, respectively. The present results suggest that though both classes of drivers can cause intense geomagnetic storm but magnetic cloud is more geo-effective than complex ejecta.

4 illus, 3 tables, 17 ref

024714   Majumdar T J;Krishna K S;Chatterjee S; Bhattacharya R;Michael L (Mar and Wat Resour Grp Remote Sens Applic Area, Space Applics Cent Indian Space Res Organization, Ahmedabad-380 015, Email: krishna@nio.org) : Study of high resolution satellite geoid and gravity anomaly data over the Bay of Bengal. Curr Sci 2006, 90(2), 211-19.

Geoid and gravity anomalies derived from satellite altimetry are gradually gaining importance in marine geo-scientific investigations. Very high-resolution gravity database generated from Seasat, Geosat GM, ERS-1 and TOPEX/POSEIDON altimeters data of the northern Indian Ocean, has been used in the preparation of geoid and free-air gravity maps. In the work, investigated various products of satellite data of the Bay of Bengal, thereby correlated to known plate tectonic feature (Sunda subduction zone), volcanic traces (Ninetyeast and 85°E ridges) and continental margin features. Besides, Swatch of No Ground and modified continental slope due to sediment discharge from East Coast rivers are some of the finer structures observed in free-air gravity anomaly data. Furthermore, the data are compared with ship-track gravity anomalies along 14.64°N lat. for their consistencies and interpreted under the constraints of seismic results for understanding the evolution of structural features of the region. Two different wavelength (100-200 and 200-500 km) components derived from satellite gravity anomaly data have been studied to explain the geophysical anomalies associated with the Ninetyeast and 85°E ridges and two isolated structures in terms of isostatic compensation due to their loads with respect to the already evolved lithosphere. It is found that the magnitude of the flexure at crust-mantle boundary beneath the 85<144>

5 illus, 36 ref

022528   Venugopal U;Narasimhulu M C;Satyanarayana K (Digital Systems Grp, ISRO Satellite Cent, Bangalore-560 017) : Fiber optic bus for space applications. J Spacecraft Technol 2006, 16(1), 62-72.

In order to meet the stringent spacecraft performances and associated complex requirements, need for lightweight and high capacity communication system as its internal bus for command and control are increasing. The advantages of fiber optic bus system over the conventional electrical bus system make it a suitable candidate for the above requirements. Activity carriedout elsewhere in this regard is reviewed here with an aim to develop a fiber optic system, which could be used in future spacecrafts of ISRO. There are advantages and at the same time there are disadvantages in using this fiber optic bus. A proper hardness assurance program at the component level, careful electrical, optical and opt electrical designs and well thought out system protocol are essential to develop a qualified fiber optic link for space application.

4 illus, 8 ref

022527   Shamrao ;Viswanatha N (Spacecraft Mechanisms Grp, ISRO Satellite Cent, Bangalore-560 017) : Antenna fine pointing mechanism (AFPM). J Spacecraft Technol 2006, 16(1), 36-40.

Future communication satellites incorporating multi-beam RF system need very accurate pointing of the antenna beams in the order of ± 0.05° or better. The pointing requirement that can be met directly by the satellite platform is limited to ± 0.2° hence, calls for a separate pointing mechanism to correct for spacecraft attitude and orbit control system pointing errors. The objective is achieved by several methods, viz.; orthogonal mounting of two rotary drives, driving two axes gimbal mechanism using rotary drives or linear actuators etc. The drawbacks of these methods are, they use gear systems and hearings, which have backlash and wear problems associated with them respectively. Describes a novel and innovative linear motor driven compliant (as the pointing range is small) mechanism, which has several advantages over the other altentative designs. The mechanism development model of compliant AFPM has been designed and the working of the mechanism has been successfully demonstrated.

7 illus, 2 ref

022526   Rana V R;Singh K P;Yadav N;Kothare A;Mukerjee K;Paul B;Pathare D;Risbud VM;Vahia N;Girish V (Dep of Astr & Astrophys, Tata Inst of Fundamental Res, Homi Bhabha Road, Colaba, Mumbai-400 005) : X-ray Optics: a new technology development for ASTROSAT and future scientific space missions. J Spacecraft Technol 2006, 16(1), 56-61.

X-ray optics based on the principle of grazing incidence is being developed for a Soft X-ray Telescope (SXT) to be flown on the first Indian astronomy mission ASTROSAT. The SXT will employ a conical approximation to the exact Wolter type I paraboloid-hyperboloid configuration for the fabrication of light-weight thin-foil gold-coated X-ray mirrors. The mirrors are being developed using a replication of smooth glass surface via gold coating, and assembled quadrant by quadrant. Details of the processes being used and tests being performed on these X-ray mirrors, as well as an outline of future prospects are described.

2 illus, 8 ref

022525   Kumar S A;Viswanathan M.;Nagendra C L;Sharma K;Pratap G;Patnaik M M M (Lab for Electro-Optics Systems (LEOS) Mechanical Systems Grp, ISRO Satellite Cent, Bangalore-560 017) : High solar absorber coatings on metallic, semiconductor and dielectric surfaces for optical attenuation applications in spacecraft systems. J Spacecraft Technol 2006, 16(1), 1-6.

Multilayer optical coating consisting of metal and dielectric layers have been designed on metallic and dielectric surfaces, which have specular reflection loss less than 1.0% in the solar spectrum covering from 400 to 1100nm. These coatings have been developed using electron beam deposition technique and qualified as per space application requirements, on a wide variety of substrates. The coated stainless steel surfaces have solar absorptance <62>98% and infrared emittance <60>20% which have been successfuly used in the Mar sensor baffles of IRS-P6 and P5. The baffles have shown a light attenuation better than 10^<-7> over a field angle <62>35°.

6 illus, 3 tables, 7 ref

022524   Karanth S;Sharma S V K;Nagendra C L (Lab for Electro-Optics Systems (LEOS), , Bangalore-560 058) : Studies on test and evaluation of N<. J Spacecraft Technol 2006, 16(1), 41-55.

Large area N^<+>-P junction Si photo-detectors are fabricated using conventional Si foundry process and opto-electronic properties namely short circuit current density J under AMO illumination, dark currently and spectral responsivitv are characterized at different temperatures. It is observed that the shallow junction devices whose junction depths are 0.5 and 0.7 microns have J_sc equal to 36.0 and 40.0 mA/cm² respectively, and the corresponding ID being respectively equal to or less than 44nA and 500 nA for an applied voltage of -2 V. The Jsc is found to be weakly dependent on temperature, over the range from 250 to 350 K which is in agreement with theory. The dark current of the devices is seen to vary in a nonlinear way with respect to temperature which has been supported theoretically. The electron damage coefficient of minority carriers is 7.8 x 10^-11 for 8 MeV electrons, over a flux of 2x10₁₃ electrons/cm². Environmental durability of the detectors is assessed as per the test conditions stipulated for space applications. It is observed that metallization bus bar and its structure are critical to produce durable detectors against adverse environmental conditions such as high temperature, thermal shock cycling and thermo vacuum baking. Devices with a tri-layer metallization coating, consisting of titanium, palladium and silver deposited by ion beam sputtering have been able to pass all the environmental tests specified for space qualification without any failure among the lot of devices.

6 illus, 5 tables, 16 ref

022523   Akila S;Kumar E K;Gopinath N S (Flight Dynamics Div Mission Dev Grp, 1SRO Satellite Cent, Bangalore-560 0071) : Orbit model studies for onboard orbit estimation. J Spacecraft Technol 2006, 16(1), 8-30.

Conventionally, Orbit Determination (OD) procedures were followed for spacecraft missions only on ground. Based on these experiences over many years and the proficiency acquired following the advent of space borne GPS receivers, onboard OD using GPS data is realized to be presenting excellent scope for a new phase of development to support advanced requirements of today as well as the futuristic missions. Better utilization of onboard radio receivers due to continuous availability of tracking data and feasibility of frequent sampling has been the key driver for the current study. The study for selection of a suitable orbit dynamics model for onboard OD is carried out using various orbit models considering relative contributions from different acceleration effects. The analysis presented includes individual effects of Central Force, Zonal Harmonics, Drag, and Luni-Solar gravitations. The study helps to logically judge the possible candidate models for onboard implementation. Clear conclusion is drawn from the study and is substantiated with the position determination for a typical low earth orbiting satellite using satellite state vector observations from GPS receivers.

9 illus, 6 tables, 4 ref

022522   Achari V T S;Devasahayam R;Joseph C C; Ravichandran M H;Simon S (NO, ISRO Inertial Systems Unit, Trivandrum) : New studies related to the improved performance in the stepper motor for Solar Array Drive Assembly (SADA) for Indian remote sensing (IRS) satellites. J Spacecraft Technol 2006, 16(1), 31-5.

Presents the design, analysis and development of 720-step high torque stepper motor for the Solar Array Drive Assembly mechanism used in IRS class satellites. The existing motor develops a peak holding torque of 1.1 Nm at 42 V with magnetic saturation and the torque pattern has the third and fifth harmonics in addition to the fundamental component. The stepper motor magnetic circuit design is optimized with FE Tools to obtain the maximum torque and make the torque pattern free from spatial harmonics without any change in overall envelope, which is implemented in the verification hardware. It is found the desaturation model develops a peak torque of 2.6 Nm as the magnetic saturation is eliminated. With the increase in permanent magnet excitation and change in tooth profile the peak torque is further improved to 5.1 Nm. The torque pattern is smoothened by providing unequal tooth pitch in stator and rotor.

11 illus, 3 tables, 3 ref

017470   Zagury F (NO, Institut Louis de Broglie, 23 rue Marsoulan, 75012, Paris, France, Email: fzagury@wanadoo.fr) : Analysis of spectra in the red rectangle nebula. J Astrophys Astr 2005, 26(4), 395-420.

Presents an analysis of series of spectra in the Red Rectangle nebula. Only the reddest part of the spectra can safely be attributed to light from the nebula, and indicates Rayleigh scattering by the gas, in conformity with the large angles of scattering involved and the proximity of the star. In the blue, light from HD 44179, refracted or scattered in the atmosphere, dominates the spectra. Questions the reliability of ground-based broad-band spectra of extended objects in the blue.

25 illus, 22 ref

017469   Zagury F (NO, Institut Louis de Broglie, 23 rue Marsoulan, 75012 Paris, France, Email: fzagury@wanadoo.fr) : Spectral analysis of the background in ground-based long-slit spectroscopy. J Astrophys Astr 2005, 26(4), 377-94.

Examines the variations, because of atmospheric extinction, of broad-band visible spectra, obtained from long-slit spectroscopy, in the vicinity of some stars, nebulae, and one faint galaxy.

12 illus, 3 tables, 10 ref

017468   Venkatakrishnan P;Sridharan R;Gupta S K (NO, Udaipur Sol Obs, Udaipur-313 004, Email: pvk@prl.ernet.in) : Imaging with insolated mirrors. Bull Astr Soc India 2005, 33(3), 265-74.

Modern solar telescope designs are different from the conventional concept of vacuum telescopes. These new designs are "open" telescopes which try to minimize the temperature difference between various parts of the telescope and the ambient air. Author address a few issues related to the thermal response and image quality of such insolated mirrors has been addressed. Estimated the distortion produced by thermal and material inhomogeneities and present limiting values of allowable temperature differences and percentage change of expansion coefficients for different aperture diameters, for typical materials under best possible seeing conditions. Predict the evolution of surface temperature of an insolated mirror using a simplified theoretical approach and show that it is compatible with the experimental values to a large extent. The results indicate the possibility of avoiding active cooling of the mirror surfaces, at least for primary mirrors with aperture diameter less than or equal to 50 cm.

5 illus, 2 tables, 6 ref

017467   Tiwari C M;Tiwari D P;Pandey A K;Shrivastava P K (Phys Dep, A.P.S. Univ, Rewa-486 003, Email: tiwaricm123@rediffmail.com) : Average anisotropy characteristics of high energy cosmic ray particles and geomagnetic disturbance index Ap. J Astrophys Astr 2005, 26(4), 429-34.

The average characteristics of the diurnal and semi-diurnal anisotropy of cosmic ray intensity at relativistic energies have been obtained by using data from the worldwide grid of neutron monitor for the period 1989 to 1996. The complex behaviour of the diurnal amplitudes and time of maxima (phase) and it s association with the Ap index on a long-term and day-to-day basis have been studied. Even though the general characteristics, on a yearly average basis, have not changed significantly during this period, both the diurnal and semi-diurnal amplitudes and phases vary significantly, besides significant changes being observed for different interplanetary conditions on a short-term basis. It is found that the relationship between the Ap index and the diurnal vector is out of phase during the period 1991 to 1995. On a long-term basis, the correlation of diurnal variation with Ap index has been found to vary during the solar cycle. On a short-term basis, it has been observed that the high Ap days are usually associated with higher amplitudes with phase shifted to earlier hours.

4 illus, 18 ref

017466   Tandon S N (NO, Inter Univ Cent for Astr and Astrophys, Post Bag No. 4, Ganeshkhind, Pune-411 007) : New opportunities for Indian space astronomy. Bull Astr Soc India 2005, 33(3), 297-302.

11 ref

017465   Tadross A L (NO, Natn Res Inst of Astr and Geophysics, 11421-Helwan, Cairo, Egypt) : A deep focus on NGC 1883. Bull Astr Soc India 2005, 33(4), 421-31.

A deep photometric analysis in the open star cluster NGC 1883 has been presented and added to the work of Carraro et al. (2003), which is the only previous work introduced for this cluster. The radius and metallicity have been re-estimated in the work. In addition, new parameters, namely luminosity function, mass function, total mass, mass segregation and the relaxation time of the cluster NGC 1883 have been estimated here for the first time.

6 illus, 31 ref

017464   Simonia I (NO, Georgian Natn Astrophysical Obs, Kazbegi Av., 2a, Tbilisi 0160, Georgia) : Frozen hydrocarbon particles of cometary halos as carriers of unidentified emissions. J Astrophys Astr 2005, 26(4), 421-7.

The possible nature of unidentified cometry emissions is under discussion. Propose a new model of the ice particles in cometary halos as a mixture of frozen polycyclic aromatic hydrocarbons and acyclic hydrocarbons. Describes principal properties of frozen hydrocarbon particles (FHPs) and suggest interpreting some of the unidentified cometary emission lines as the photoluminescence of FHPs. The results of comparative analysis are present.

12 ref