http://nopr.niscair.res.in/handle/123456789/4004 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/4019 Title: Gunn loaded microstrip antenna with parasitic elements <br/> <br/>Authors: Ansari, J A; Dubey, Satya Kesh; Singh, Prabhakar; Vishvakarma, Babau R; Khan, R U <br/> <br/>Abstract: An analysis of Gunn loaded patch with parasitic elements at radiating edges of the patch has been carried out using equivalent circuit concept for different values of bias voltage and threshold voltage. It is observed that addition of parasitic elements improves the band of operation to 400 MHz (bandwidth 4.48%, center frequency 8.95 GHz) as compared to 297 MHz (bandwidth 3.06%, center frequency 8.90 GHz) for Gunn loaded patch. Antenna also shows tunability of 50 MHz for bias voltage from 8 to 15 V for a given threshold voltage of 4.4 V and exhibits enhanced radiation by 0.5833 dB as compared to patch alone. Various parameters of the antenna are compared with simulated data using IE3D. <br/> <br/>Page(s): 116-121 http://nopr.niscair.res.in/handle/123456789/4018 Title: Dielectric properties of black soil with organic and inorganic matters at microwave frequency <br/> <br/>Authors: Navarkhele, V V; Shaikh, A A; Ramshetti, R S <br/> <br/>Abstract: The dielectric properties of black soil have been studied with addition of organic (vermi compost) and inorganic (calcium carbonate) matter. Microwave transmission line waveguide technique has been used for this purpose. The dielectric properties [dielectric permittivity ( Ɛ') and dielectric loss ( Ɛ'')] have been measured for four different frequencies at room temperature. The experimental observations show that Ɛ' and Ɛ'' decrease with increasing frequency of oscillation, and increases with increasing percentage volume of organic and inorganic matter. The results show that dielectric values obtained with organic matter are higher than that of inorganic matter. <br/> <br/>Page(s): 112-115 http://nopr.niscair.res.in/handle/123456789/4017 Title: Space disturbance effect on equatorial sporadic-E during sunrise <br/> <br/>Authors: Rastogi, R G; Chandra, H <br/> <br/>Abstract: <smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="City" downloadurl="http://www.5iamas-microsoft-com:office:smarttags"><smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="place" downloadurl="http://www.5iantlavalamp.com/"> The space weather event of 25 September 1998 and its effect in the E-region near magnetic equator has been studied. The geomagnetic H field variations recorded at low latitudes was normal on 24 and 26 September 1998 but there was a geomagnetic storm on 25 September with sudden commencement at 0445 hrs LT (75^o EMT). There was a strong counter electrojet after sunrise associated with the magnetic storm. Solar wind speed and ion density and the interplanetary magnetic field (IMF) data show the IMF B_Z turning towards south in the morning on 25 September 1998 and solar wind velocity was 850 kms^-1. Quarter hourly ionograms at Thumba, located close to the dip equator were examined during morning hours on 24-26 September 1998. On 24 and 26 September 1998, E-region irregularities (E_s-q) were first generated about an hour after the appearance of fresh E-region ionization following sunrise and by the time DH at Trivandrum started increasing above the corresponding value at Alibag. On the disturbed day, 25 September 1998, E_s-q appeared later due to occurrence of counter electrojet after sunrise. This is caused by electric field changes associated with the magnetic storm rather than the late reversal of the electric field in the morning. </smarttagtype></smarttagtype> <br/> <br/>Page(s): 105-111 http://nopr.niscair.res.in/handle/123456789/4016 Title: Particle associated polycyclic aromatic hydrocarbons in urban air of Agra <br/> <br/>Authors: Rajput, Nirat; Lakhani, Anita <br/> <br/>Abstract: <smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="City" downloadurl="http://www.5iamas-microsoft-com:office:smarttags"><smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="place" downloadurl="http://www.5iantlavalamp.com/"><smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="country-region" downloadurl="http://www.5iantlavalamp.com/"> Total suspended particulate matter (TSPM) samples were collected at Nunhai, Agra from May 2006 to September 2006. Since polycyclic aromatic hydrocarbons (PAHs) are known carcinogenic and mutagenic, concentrations of 16 PAHs in aerosols were quantified in the present paper. The dominating PAHs in TSPM include high molecular weight Benzo(ghi)Perylene, dibenzo(b)anthracene, indeno(123cd) pyrene, benzo(a)pyrene. Naphthalene and acenapthylene being more volatile were not detected in any of the samples. The sum of 14 PAHs ranged 150 - 480 ng m^-3with a mean value of 269 ± 121 ng m^-3. The results indicate that PAH concentrations are higher than other industrial sites but are comparable to those measured in several urban Chinese cities, however, less than the industrial locations of China. Higher PAH concentrations are attributed to higher rates of emissions as well as greater scavenging and adsorption of vapor phase PAH on available TSPM. The potential sources of PAHs in aerosols were identified using the diagnostic ratios between PAHs. The vehicular emissions were the main contributors of particulate-associated PAHs and stationary combustion sources also contribute to the particulate PAHs. PAHs in aerosols were predominantly from gasoline and diesel engines. </smarttagtype></smarttagtype></smarttagtype> <br/> <br/>Page(s): 98-104