Papers

Porous silicon is obtained by electrochemical etching of single crystalline silicon with 48% hydrofluoric acid. In this work we calculate energy gap DE for different visible wavelengths in the white light spectrum by treating energy levels in the bands of porous silicon as Bohr levels. This emission of monochromatic visible wavelengths is related to porous density of porous silicon (p-si) material. These visible wavelengths are expected to be emitted from degenerate energy levels above band gap.
 

5-Iodoanthranilic acid, 5-bromo anthranic acid, acetanthranils or benzoxazinones, 2-methyl-3-(p-methylphenyl)-6-iodo quinazolin-4(3H)-ones, 2-bromomethyl-3-(p-methylphenyl)-6- iodoquinazolin-4(3H)-ones, 2-hydrazino methyl-3-(p-methylphenyl)-6-iodoquinazolin-4(3H)-ones,1-[2'-methylene-3-(p-methylphenyl)-6-iodoquinazolin-4(3H)-onyl-4-(ochlorophenyl)-2-(2''-phenylindol-3''-yl)-2-pyrazolines have been prepared. Their structures have been established by elemental analysis. IR spectra, NMR spectra and mass spectra. All the compounds have been tested for their anti-inflammatory activity, analgesic activity, ulcerogenic activity and cyclooxygenase activity.
 

In the present study, a Single sloped cascade solar distillation unit with total evaporation area of 0.996 sqm was fabricated and the performance analysis has been carried out during the months of April, May, June and July in the year 2006 at solar energy laboratory of Physics Department, Avinashilingam University, Coimbatore. Temperatures of water, glass cover and step temperature were recorded at regular intervals using thermocouples. Insolation, ambient temperature, and wind velocity were also recorded on sunny as well as cloudy days The daily distillate output varies between 2000-2500ml on sunny days from 9.00AM to 4.00PM., while the solar insolation varies between 700-870 w/m2. The daily distillate output varies between 880-1900ml on cloudy days between 9.00AM to 4.00PM., while the solar insolation varies between 330-700 w/m2. The nocturnal distillate output varies between 200-500ml. The efficiency of this solar still was found to be in the range of 20-30%.

We have made an attempt to study magnetohydrodynamic (MHD) disturbances inside the coronal arcades by solving a pair of second-order two dimensional partial differential equations. MHD modes of oscillations of coronal arcades are investigated. It has been shown that the factors responsible for oscillatory modes give rise to the propagation of MHD waves.

A series of 2-Methyl-3-(4-hydroxyphenyl)-6-chloro quinazolin-4(3H)-ones (1-6), 2-bromomethyl-3-(4-hydroxyphenyl)-6-chloroquinazolin-4(3H)-ones (7-12), 2-hydrazinomethyl-3-(4-hydroxyphenyl)-6-chloroq- uinazolin-4(3H)-ones (13-18), 2-(2'-methylindol-3'-yl-imino) amino methyl-3-(4-hydroxyphenyl)-6-chloroquinazolin-4(3H)-ones (19-24), 2-[4'-oxo-5'-substituted-2'-(2''-methylindol-3''-yl) thiazolidin-1-yl]-aminomethyl-3-(4-hydroxyphenyl)-6-chloroquinazolin-4(3H)-ones (25-30) have been synthesized. The structures of these compounds have been confirmed by elemental analysis and spectral data such as IR, NMR and mass spectra. These compounds were also evaluated for their biological study such as anti-inflammatory, ulcerogenic and analgesic activities.
 

Chester - Chesnell- Whitham method has been applied to study the propagation of strong spherical shock in the heat radiating atmosphere having uniform density distribution. Neglecting the effect of overtaking disturbances the analytical expressions for shock velocity, shock strength, particle velocity and pressure have been obtained using Bhowmick conditions. The results obtained here are compared with those for non-radiating heat atmosphere.
 

The goal of Third Generation (3G) mobile communication systems is to provide users not only with the traditional circuit switched services, but also with high speed Internet access, video conferencing and multimedia applications. Universal Mobile Telecommunication System is the 3G mobile communication system specified by European Telecommunications Standards Institute. Wideband CDMA is the physical layer of UMTS Terrestrial Access Network. WCDMA employs direct-sequence code division multiple access Technology. The main limitation of this technology is multiple access interference. MAI is thus a major factor, which limits the capacity and the performance of a DSCDMA system. The conventional detector is a bank of correlators and it follows a single-user detection strategy The drawbacks of the single-user detector are that it is interference-limited and it also suffers from the near-far problem. A better detection strategy is Multi-User Detection. MUD reduces the MAI effect by jointly using information of multiple users to better detect each user. This increases the system performance as well as system capacity. Multi-user detection techniques are essential for achieving near optimal performance in communication systems. Therefore, the addition of multi-user detection capabilities to various network elements promises to be the key for enabling significant increase in capacity needed for 3G mobile systems.
I . OBJECTIVE :
The objective of the paper is to study the effects of subtractive interference cancellation detectors namely the SIC and PIC Detectors on the performance of WCDMA uplink transmi- ssion. We have implemented the WCDMA uplink end-to-end physical layer in MATLAB and compared the performance of multi-user detection with single-user detection. Factors such as the number of simultaneous users and channel estimation are taken into consideration, for three main UMTS channels namely: Indoor ChannelA, Pedestrian Channel A and Vehicular Outdoor Channel A.
II. HELPFUL HINTS :
 

The quality of ground water depends on the ion, which are dissolved in ground water. The major ions which are responsible to maintain the quality of ground water are carbonate (CO32-.) and bicarbonate(HCO3-1), Chloride (Cl-1), sulphate (SO4-2), nitrate (NO3-1), phosphate (PO4-3), fluoride (F-1). These ions are present in anionic form. The cation and anion must be equal to maintain the quality of water cation such as Ca2+, Mg2+,Na+ and K+ are also present in ground water in form of hardness and salinity. 10 water samples are collected from Narwar Block (Shivpuri District) for post mansoon season (2004). The ionic concentration is expressed in mg/L.
 

Bhopal, the capital of M.P. has twenty five lakes from which upper lake, lower lake and shahpura lake are more important lakes. There are almost 115 hospitals and nursing homes in Bhopal and Many hospitals are going to be setup here, which will increase the pollution load on water bodies. The hospital effluent and sewage contribute the source of pollution in lake water. The physical and chemical parameters have been analyzed. The results show that the hospital effluent deteriorates the quality of lake water significantly. Present study reveals the effect of discharge of untreated hospital effluent into the lake.

In the present work, the sample of the pyrite and aresenopyrite mineral were collected from Malanjkhand open pit mines of Balaghat district of Madhya Pradesh and Bhimsen Kila Pahar block of Bhandara district Maharashtra State to study the structural and physical studies of the samples in Laboratory. The samples has been characterized by X-ray diffraction technique and revealed that the first sample was possesses cubic crystal structure with pyrite structure and preferred orientation along (311) plane with the space group Pa3 and point group 2/m3. The value of lattice parameter a for the pyrite sample is found to be 5.417 ºA and the second sample was possesses monocline structure with arsenopyrite along (210) plane with space group P21/c and point group 2/m. The value of lattice parameter a, b and c are found to be 5.741 ºA, 5.668 ºA and 5.770 ºA respectively. The d.c. electrical resistivity measurement have been carried out over temperature range of 300° to 800°K. The temperature dependence of electrical resistivity exhibited activation energies. The magnetic susceptibility value are found to be 96.91 x 10-8m3kg-1 and 11.09 x 10-8m3kg-1 (S.I. unit). These values were compared with the standard data and showed that the samples are having cubic and monoclinic structure, semiconductor behavior and paramagnetic which become ferromagnetic after applied external field.