008517   Goel G;Sharma P;Singh R;Setia B (Civil Engineering Dep, Sharda Univ, Greater Noida) : Optimal use of surface drains for enhancing ground water recharge. J Indian Wat Resour Soc 2013, 33(3), 43-52.

Employing the observed natural rainfall-runoff data, this study investigates the effect of slope of experimental plots having maize crop on the resulting runoff curve number, the only parameter of the Soil Conservation Service Curve Number (SCS-CN) methodology. The soil of field plots of all 1%, 3%, and 5% slopes when tested for infiltration using double ring infiltrometer was found to fall in Hydrologic Soil Group 'C'. For the same soil, land use, and rainfall, CN-values were found to increase with slope, and vice versa.

7 illus, 10 ref

008516   Gill S;Rani S;Singh N (Applied Physics Dep, Institute of Engineering and Technology Univ, Kurukshetra-136 119, Email: savitamaggie@gmail.com) : Higher order amplitude squeezing in fourth and fifth harmonic generation. Indian J Phys 2012, 86(5), 371-5.

The quantum effect of squeezing of electromagnetic field has been investigated in the fifth order amplitude in fundamental mode in fourth and fifth harmonic generation under the short time approximation. It has been observed that squeezing depends on coupling constant g and phase of the field amplitude. The effect of photon number on squeezing and the variation of signal-to-noise ratio in fifth order of field amplitude for a squeezed state with photon number has also been investigated.

5 illus, 25 ref

008515   Ghosh U N;Chatterjee P (Mathematics Dep, Siksha Bhavana, Visva Bharati, Santiniketan, West Bengal-731 235, Email: unghosh1@rediffmail.com) : Head-on collision of dust acoustic solitary waves in a dusty plasma with nonthermal ions. Indian J Phys 2012, 86(5), 407-11.

The head-on collision of dust acoustic solitary waves in a three-component unmagnetized dusty plasma with Boltzmann distributed electrons, nonthermal ions and negatively charged dust grains has been investigated using the extended Poincare-Lighthill-Kuo method. The effects of the ratio of electron temperature to ion temperature on the phase shift have also been studied. It is found that the presence of nonthermal ions play a significant role on the collision of dust acoustic solitary waves. There are real implementation of present results in different regions of space, viz cometary tails, upper and lower mesosphere, Jupiter's magnetosphere, etc.

3 illus, 51 ref

008514   Gahlaut V;Sharma R K;Srivastava V;Alvi P A; Ghosh S K (Microwave Tubes Div, CSIR-Central Electronics Engineering Research Institute, Pilani-333 031, Email: vgceeri@gmail.com) : Effect of ceramic material on heat dissipation from multi-stage depressed collector used in high efficiency traveling-wave tubes. Indian J pure appl Phys 2013, 51(9), 657-60.

To increase reliability, the thermal and structural integrity of a multi-stage depressed collector (MDC) used in traveling wave tubes (TWTs) has been improved. Highly reliable TWTs can be achieved by careful consideration of design requirements and constraints, material selection, weight reduction and cost effectiveness. In a TWT, maximum heat generated in MDC is due to maximum power dissipation and, hence, needs for proper thermal management. In the present paper, the thermal characteristics of MDC for different ceramic insulator materials have been studied.

8 illus, 1 table, 8 ref

008513   Degheidy A R;Elabsy A M;Abdelwahed H G; Elkenany E B (Physics Dep, Faculty of Science Mansoura Univ, P.O. Box 35516, Mansoura, Egypt, Email: kena@mans.edu.eg) : Pressure dependence of the electronic structure in Ge, GaP and InP semiconductors at room temperature. Indian J Phys 2012, 86(5), 363-9.

The electronic structure of Ge, GaP and InP semiconductors under hydrostatic pressure based on the empirical pseudopotential method have been reported. The pressure coefficients, pressure dependent form factors, of the main band gaps at Γ, X and L symmetry points in the Brillouin zone have been calculated. We have found that most of the values of the electronic energy bands were more sensitive to the pressure dependent form factors associated with the reciprocal lattice vectors of = 11 than any other value. Our calculations for the energy gaps of the semiconductors under investigation at different pressures have been found to be in excellent agreement with available experimental data.

6 illus, 37 ref

008512   Choudhury D K;Choudhury R (Physics Dep, Gauhati Univ, Guwahati-781 014, Email: rabrchran@yahoo.co.in) : Approximate analytic solutions of spin dependent coupled Altarelli-Parisi equations using method of successive iteration. Indian J Phys 2012, 86(5), 377-82.

In order to obtain analytic solutions of the spin dependent coupled Altarelli-Parisi equations at leading order (LO) in the small x limit we have applied here the method of successive iterations. We have shown that barring the small x limit of the splitting functions at LO, this method does not require any other adhoc assumptions to obtain analytic solutions of the coupled AP equations. We have observed that, after successive iterations our solutions come closer to the exact numerical results.

4 illus, 24 ref

008511   Choudhary S;Sengwa R J (Dielectric Research Laboratory, Physics Dep, JNV Univ, Jodhpur, 342 005, Rajasthan, Email: rjsengwa@rediffmail.com) : Dielectric properties of PEO-PVP-MMT nanocomposite hydrocolloids. Indian J Phys 2012, 86(5), 335-40.

The relative complex dielectric function, electric modulus, alternating current electrical conductivity and complex impedance behaviour of aqueous poly(ethylene oxide) (PEO) and poly(vinyl pyrrolidone) (PVP) blend with montmorillonite (MMT) clay nano-platelets as colloidal suspensions have been investigated over the frequency range 20 Hz to 1 MHz at 15, 30 and 45 °C. The direct current ionic conductivity and real part of permittivity of the hydrocolloids have increased whereas electrode polarization relaxation time has decreased with the increase of MMT concentration, and these dielectric parameters have significantly varied with change of the temperature. The hydrogen bond complex formation between PEO, PVP and dispersed MMT nano-platelets in aqueous solutions has been discussed. The correlation between complex structures and the dielectric parameters of these materials have been confirmed.

6 illus, 46 ref

008510   Chauhan S;Kuldeep Kumar;Patial B S (Chemistry Dep, H P Univ, Shimla-171 005, Email: chauhansuvarcha@rediffmail.com) : Acoustic parameters of proline in lecithin-ethanol mixture at varying temperature. Indian J pure appl Phys 2013, 51(8), 531-41.

The solution behaviour of proline in lecithin-ethanol mixture as a function of temperature and composition have been investigated by measuring velocity of sound in conjunction with density at different temperature in the range 25-40°C at an interval of 5°C. Various acoustical parameters such as intermolecular free length (L_f), relative association (RA), specific acoustic impedance (z), relaxation time (τ), sound velocity number (U), molar volume (V_m) and internal pressure (π_i) have been evaluated from velocity of sound, density and viscosity measurements. The intermolecular free length (L_f) varies linearly with the concentration of proline and increases with rise in temperature. The linear trend in L_f values with the concentration of proline has been supported by the trend obtained from τ values. The excess values of these parameters have also been calculated and their trends of variation are discussed in terms of the presence of significant molecular interactions between the component molecules in the mixtures.

3 illus, 2 tables, 34 ref

008509   Chandra S;Ghosh B (Physics Dep, Jadavpur Univ, Kolkata-700 032, Email: swarniv147@gmail.com) : Non-linear propagation of electrostatic waves in relativistic Fermi plasma with arbitrary temperature. Indian J pure appl Phys 2013, 51(9), 627-33.

Modulational instability of electron plasma waves has been investigated by using the quantum hydrodynamic (QHD) model for quantum plasma at finite temperature by deriving a non-linear Schrodinger equation including relativistic effects. It is shown that the electron degeneracy parameter and streaming velocity significantly affect the linear and non-linear properties of electron plasma waves in a finite temperature quantum plasma.

8 illus, 24 ref

008508   Chakrabarti S K (NO, SN Bose National Centre for Basic Sciences, JD-Block, Salt Lake, Kolkata, 700 098, Email: chakraba@bose.res.in) : VLF signals in summer and winter in the Indian sub-continent using multi-station campaigns. Indian J Phys 2012, 86(5), 323-4.

Carried out 2 week-long campaigns in Indian winter and summer to study VLF signals from the Indian navy transmitter (VTX) operating at 18.2 kHz. Authors have used more than a dozen of receivers scattered throughout the Indian sub-continent in each of these campaigns. To our knowledge, this is the largest campaign of its kind in this region. The propagation paths range from 500 km to almost 3,000 km covering an area of about 4 million sq km. We have presented the results of the amplitude variation of the diurnal signal at each of these receiving stations in winter and summer and compare them. We have clearly found the non-reciprocity of the east to west and west to east propagation. Our results generally agree with the signal shapes obtained using the long wave propagation capability code based on mode propagation through the Earth-ionosphere cavity.

11 illus, 29 ref

008507   Bhujbal P M;Dhoble S J (Physics Dep, Nutan Adarsh Arts, Commerce and Smt. M. H. Wegad Science College, Umrer-441 203, Email: sjdhoble@rediffmail.com) : Mechanoluminescence characterization of γ-rays irradiated NaBr:Ce<. Indian J Phys 2012, 86(5), 383-6.

The mechanoluminescence (ML) of γ-irradiated coloured powder of NaBr:Ce(0.1-10 mol%) phosphor are reported in this paper and compared with pure NaBr material. All samples were prepared by wet-chemical method. Single isolated ML glow curve is observed in all samples. The variation of peak ML intensity with gamma exposure and with different concentration of Ce³⁺ doped, in NaBr:Ce are studied. ML intensities are found to be dependant on concentrations of Ce³⁺ and gamma radiation dose. The variation of peak ML intensity of NaBr:Ce(0.5 mol%) with different gamma dose is found as sublinear up to 2.5 kGy high dose of γ-irradiation.

4 illus, 28 ref

008506   Bhowmick S K;Ghosh N K (Physics Dep, Kalyani Univ, Kalyani-741 235, Email: nanda.ku@rediffmail.com) : Falicov-Kimball model extended by next-nearest-neighbor (NNN) hopping of d-electrons. Indian J Phys 2012, 86(5), 145-9.

The role of next-nearest-neighbor (NNN) hopping of the d-electrons in the mixed-valence phenomena has been investigated. Falicov-Kimball model extended by NNN hopping has been considered. Calculations have been made both at zero and at finite temperatures. It has been observed that NNN hopping (i) shifts the d-level energy, (ii) makes the system more disordered, (iii) decreases degeneracy of the ground state and (iv) has important effects on the spin susceptibility. Antiferromagnetic type exchange interaction has also played similar role as NNN hopping in the spin susceptibility χ.

6 illus, 27 ref

008505   Bhatt A;Sharma G;Munish Kumar (Physics Dep, G B Pant Agriculture and Technology Univ, Pantnagar-263 145, Email: munish_dixit@yahoo.com) : Search of an equation of state for nanomaterials. Indian J pure appl Phys 2013, 51(9), 642-50.

An effort is made to search a suitable equation of state (EOS) model for the nanomaterials. Six EOS models based on different physical origins viz. Brich-Murnaghan model, Murnaghan model, Kumar model, Vinet model, Freund and Ignalls model and Tallon model are used to study the compression behaviour of thirty one nanomaterials. The results are compared with the available experimental data. It is concluded that the Murnaghan model performs well for the materials considered in the present paper for the pressure ranges considered in the experimental studies of these materials. It is also discussed that the Murnaghan model may be obtained using different concepts.

27 illus, 2 tables, 36 ref

008504   Bavarnegin E;Moghaddam M V;Fathabadi N (Physics Dep, Guilan Univ, Rasht, Iran, Email: ebavarnegibn@gmail.com) : Natural radionuclide and radiological assessment of building materials in high background radiation areas of Ramsar, Iran. J med Phys 2013, 38(2), 93-7.

Building materials, collected from different sites in Ramsar, a northern coastal city in Iran, were analyzed for their natural radionuclide contents. The measurements were carried out using a high resolution high purity Germanium (HPGe) gamma-ray spectrometer system. The activity concentration of ²²⁶Ra, ²³²Th, and ⁴⁰K content varied from below the minimum detection limit up to 86,400 Bqkg^-1, 187 Bqkg^-1, and 1350 Bqkg^-1, respectively. The radiological hazards incurred from the use of these building materials were estimated through various radiation hazard indices. The result of this survey shows that values obtained for some samples are more than the internationally accepted maximum limits and as such, the use of them as a building material pose significant radiation hazard to individuals.

2 illus, 2 tables, 28 ref

008503   Bafna M K;Sen P;Sen P K (Applied Physics Dep, Mandsaur Institute of Technology, Indore, Email: mkbafna@gmail.com) : Coherent transient effects in a InGaAs_1-x/GaAs semiconductor quantom dot. Indian J pure appl Phys 2013, 51(8), 553-7.

Present a theoretical analysis to examine the strain effect on light and heavy hole energy levels and role of exciton and bi-excitons on the absorptive optical mutation in In_xGa_1-xAs/GaAs quantum dots (QDs) near the band edge. The analysis is based upon the strain induced Luttinger Hamiltonian and time dependent perturbation technique of the coherent radiation-semiconductor interaction model for a three-level system under near band gap resonant excitation regime. The relaxation and dephasing mechanisms phenomenological have been incorporated. Numerical estimations of refractive and absorptive optical mutation have been made for a InGaAs/GaAs quantum dot duly shined by femtosecond pulse Ti: sapphire laser. Our results are found to agree qualitatively with available experimental observations.

3 illus, 15 ref

008502   Aravindan V;Vickraman P (Physics Dep, Gandhigram Rural Univ, Gandhigram-624 302, Email: aravind_van@yahoo.com) : Effect of aging on the ionic conductivity of polyvinylidenefluoride-hexafluoropropylene (PVdF-HFP) membrane impregnated with different lithium salts. Indian J Phys 2012, 86(5), 341-4.

The aging towards the ionic conductivity have been studied using of different lithium salts namely, lithium bis(oxalate)borate (LiBOB), lithium difluoro(oxalato)borate (LiDFOB), lithium fluoroalkylphosphate (LiFAP) and LiPF₆ in polyvinylidenefluoride-hexafluoropropylene (PVdF-HFP) matrix. The crystallization behavior of LiBOB and LiDFOB has been noticed for the first time during storage of such membranes within the texture of PVdF-HFP matrix. At the same time, such behavior has not been observed in the case of LiFAP and LiPF₆ based membranes. The growth of such crystallites would certainly hinder the mobility mechanism of Li⁺ ions and it has been confirmed by ionic conductivity measurements. The formation of such crystals has been validated through scanning electron microscopic studies.

2 illus, 21 ref

008501   Al-Awfi S (Physics Dep, Faculty of Science Taibah Univ, P.O. Box 3002, Medina, Saudi Arabia, Email: alawfi99@hotmail.com) : Theory of evanescent plasmon-mode optical lattices with metallic layer. Indian J pure appl Phys 2013, 51(8), 546-52.

How a surface plasmon optical lattice can be produced when an ordinary Hermite-Gaussian light is totally reflected internally at the planar surface of a dielectric on which the finite thickness of metallic layer has been deposited, has been studied in the present paper. The characteristic property of such a light is the exponential decay with distance in a vacuum which can basically provide a two-dimensional optical lattice with attractive enhancements with the strongly trapped intensity distribution decays with distance vertical to the metallic surface. The detailed characteristics of this lattice structure depend on the input light parameters and the dielectric mismatch of the media. As well as this, they can be controlled by varying the incident angle and the order of the Hermite-Gaussian light.

4 illus, 20 ref

008500   Akbari-Moghanjoughi M (Faculty of Sciences, Physics Dep, Azarbaijan Tarbiat Moallem Univ, 51745-406 Tabriz, Iran, Email: m_akbari@azaruniv.edu) : Higher-order nonlinear electron-acoustic solitary excitations in partially degenerate quantum electron-ion plasmas. Indian J Phys 2012, 86(5), 413-22.

Propagation of dressed solitary excitations are studied in a partially degenerate quantum plasma in the framework of quantum-hydrodynamics model using multiple scales technique. The evolution equation together with a linear inhomogeneous differential equation is solved using Kodama-Taniuti renormalizing technique. It is shown that the type of solitary excitations (bright or dark) is defined by two critical plasma parameter values.

4 illus, 30 ref

007363   Srinivasu C;Narendra K;Kalpana C (Physics Dep, Andhra Loyola College, Vijayawada-520 008, Email: kollanarendra@rediff.com) : Thermo acoustical excess parameters of anisaldehyde- toluene mixture at 303.15, 308.15, 313.15 and 318.15 K. Asian J Chem 2011, 23(6), 2681-4.

Ultrasonic velocity, density and viscosity in binary liquid mixture of anisaldehyde + toluene have been determined at different temperatures from 303.15-318.15 K over the whole composition range. The data have been utilized to estimate the excess adiabatic compressibility (β^E), excess volume (V^E), excess intermolecular free length (L_f ^E), excess internal pressure (π^E), excess enthalpy (H^E) and excess viscosity (η^E) at these temperatures. The excess values have been found to be useful in estimating the strength of the interactions in the liquid mixtures. Analysis of these parameters indicates that there are weak interactions among the components of the binary mixtures.

8 illus, 1 table, 23 ref

007362   Mondal S;Mitra P (Physics Dep, Burdwan Univ, Golapbag-713 104, Email: mitrapartha1@rediffmail.com) : Effect of manganese incorporation in ZnO thin films prepared by SILAR. Sci Soc 2012, 10(2), 139-46.

Pure and Manganese doped zinc oxide (Mn: ZnO) thin films were deposited on microscope glass slides following successive ion layer adsorption and reaction (SILAR) technique. Characterization techniques of XRD, SEM and UV-visible spectrophotometer were done to investigate the effect of Mn doping on the structural and optical properties of Mn:ZnO thin films. Structural characterization by X-ray diffraction reveals that the strong preferred c-axis orientation is lost and polycrystalline nature of the films increases due to Mn doping. Incorporation of Mn was confirmed from elemental analysis using EDX. The optical band gap of the films decreases due to Mn incorporation. The value of fundamental absorption edge is 3.20 eV for pure ZnO and it decreases to 3.04 eV for 5% Mn:ZnO.

5 illus, 16 ref

007361   Danodia P;Avish Munjal (NO, Visvesvaraya National Institute of Technology (NIT), Nagpur, Email: pankajdanodia@gmail.com) : Renewable energy. Int J latest Technol Engng Mgmt appl Sci 2013, 2(5), 8-10.

Most renewable energy comes either directly or indirectly from the sun. Sunlight, or solar energy, can be used directly for heating and lighting homes and other buildings, for generating electricity, and for hot water heating, solar cooling, and a variety of commercial and industrial uses. Climate change and global warming concerns, coupled with high oil prices, peak oil, and increasing government support, are driving increasing renewable energy legislation, incentives and commercialization. New government spending, regulation and policies helped the industry weather the global financial crisis better than many other sectors. According to a 2011 projection by the International Energy Agency, solar power generators may produce most of the world's electricity within 50 years, dramatically reducing the emissions of greenhouse gases that harm the environment.

7 ref

007360   Anjaiah J;Laxmi Kanth C;Ranga Reddy Y; Kistaiah P (Physics Dep, Geethanjali College of Engineering and Technology, Keesara, RR Dist.- 501 301, Email: anjaiah.juluru@gmail.com) : Thermoluminescence studies on Li₂O-MO-B₂O₃ glasses doped with rare earth ions. Asian J Chem 2011, 23(6), 2696-700.

Thermoluminescence (TL) characteristics of X-ray irradiated pure and doped with four different rare earth ions (viz., Pr³⁺, Nd³⁺, Sm³⁺ and Eu³⁺) lithium borate glasses mixed with the three different modifiers ZnO, CaO and CdO have been studied in 303-573 K. All the pure glasses have exhibited single thermoluminescence peak at 382, 424 and 466 K, respectively. When these glasses are doped with different rare earth ions no additional peaks are observed but the glow peak temperature of the existing glow peak shifted gradually towards higher temperatures with gain in intensity of thermoluminescence light output. The area under the glow curve is also found to be maximum for Eu3+ doped glasses. The glasses containing CdO as modifier have exhibited the maximum thermoluminescence light output. The trap depth parameters associated with the observed thermoluminescence peaks have been evaluated using Chen's formulae. The possible use of these glasses in radiation dosimetry has been described.

8 illus, 4 tables, 16 ref

006369   Wang B J;Jiang M (Materials Engineering School, Panzhihua Univ, Sichuan-617 000, China, Email: xkjwbj01@163.com) : Theoretical explanation and optical spectra of vanadium(III) doped copper aluminum sulfide. Indian J Phys 2012, 86(4), 297-9.

The ESR and optical spectra of CuAlS₂: V³⁺ has been studied by using crystal- and ligand-field theory. The energy Hamiltonian and ESR formulae for 3d² electronic configurations at a tetragonal MX₄ complex have been derived from the two spin-orbital coupling parameters model. The contribution from the spin-orbit coupling of the ligand to ESR and optical spectra has been considered in the calculations. The calculated results are in good agreement with the experimental findings and show that V₃₊ ion substitutes for Cu⁺-site.

3 tables, 26 ref

006368   Upadhyaya H P;Saha A;Kumar A;Naik P D (Radiation and Photochemistry Div, Bhabha Atomic Research Centre, Trombay, Mumbai-400 085, Email: pdnaik@barc.gov.in) : Ultraviolet photodissociation dynamics of trichloroethylene at 235 nm. Indian J Phys 2012, 86(3), 165-71.

The photodissociation dynamics of trichloroethylene was investigated near 235 nm, (π,π*) transition, by detecting the nascent products, Cl (²P_3/2 and Cl* (²P_1/2), via 2+1 resonance enhanced multiphoton ionization. The photofragment speed distribution, the recoil anisotropy parameter β and the spin-orbit branching ratio for chlorine atom elimination channels were determined from time of flight profiles in polarization experiments. Based on the dynamical information, the features of potential energy surface along the reaction coordinate were discussed.

6 illus, 29 ref

006367   Sinha R K;Singh B P;Kundu T (Physics Dep, Indian Institute of Technology, Bombay, Mumbai-400 076, Email: tkundu@phy.iitb.ac.in) : Effect of electronic states coupling on methyl torsion in 3-methylisoquinoline. Indian J Phys 2012, 86(3), 187-94.

Spectroscopic studies on jet cooled 3-methylisoquinoline using fluorescence excitation and dispersed fluorescence methods were carried out. The effect of methyl substitution on the excited state behavior of isoquinoline is focused. Methyl torsional behavior and the effect on torsional potential of methyl group due to excited states mixing are addressed. The possible explanations of the observed intensity pattern of the torsional transitions in the fluorescence excitation spectrum are also presented.

7 illus, 2 tables, 38 ref

006366   Singh P K (Physics Dep, Institute of Basic Sciences, Khandari, Agra-282 002) : Analysis of high derivative thermoelastic properties of MgO. Indian J Phys 2012, 86(4), 259-65.

Author studied high derivative thermoelastic properties such as the pressure derivatives of bulk modulus and the volume dependence of the Griineisen parameter in case of MgO for a wide range of pressures down to compression V/V0 = 0.6, and temperatures up to 3,000 K approaching the melting temperature. Used the isothermal pressure-volume equation of state (EOS) based on the adapted polynomial expansion of second order (AP2) due to Holzapfel. The results for the P-V-T relationships and high derivative properties have been obtained using the Holzapfel AP2 EOS. The pressure derivatives of bulk modulus and volume derivatives of the Gruneisen parameter have been determined using the free volume theory. A relationship between the pressure derivative of bulk modulus and the ratio of pressure and bulk modulus has been found to hold good.

4 illus, 8 tables, 41 ref

006365   Shirhatti P R;Wategaonkar S (NO, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai-400 005) : Mass analyzed threshold ionization (MATI) spectroscopy of p-cresol. Indian J Phys 2012, 86(3), 159-64.

Experimental setup was developed for carrying out the mass analyzed threshold ionization (MATI) spec-troscopy. Primary objective has been to carry out the vibronic spectroscopy of the novel hydrogen bonded complexes in the cationic state. To this end MATI spectroscopy is best suited for the purpose. This work presents the successful implementation of the same using p-cresol as a test case. This happens to be the prime substrate in most of studies on weakly hydrogen bonded complexes that are dominated by the dispersion interaction contrary to the electrostatic nature of the conventional hydrogen bonds. The adiabatic ionization potential of-cresol was determined as 65,904 ± 10 cm^-1 which is in good agreement with the previously reported value. The MATI spectrum also shows a few vibronic bands of p-ciesol cation.

6 illus, 1 table, 14 ref

006364   Sathish L A;Nagaraja K;Shobha S;Sundareshan S;Jeyabalan S (Physics Dep, Government Science College, Bangalore, Email: lasgayit@yahoo.com) : Distribution of indoor radon and thoron levels. J Envir Res Dev 2011, 6(1), 34-40.

The sources of indoor radon levels are the soil-gas, building materials, tap water, natural gas used for cooking, etc. The concentrations of ²²²Rn, ²²⁰Rn and their progeny levels in dwellings were measured using Solid State Nuclear Track Detectors. The higher concentrations were observed in a room of lower volume than in higher volume. The concentrations in a dwelling of volume 35-300 m³ ranged from 6 to 93 Bq m^-3. It is observed that the enhancement of volume by almost ten-fold reduces the concentration of ²²²Rn to 11.1%; and that of ²²⁰Rn to 8.3% provided the rest of condition remains unaltered. The result clearly indicates that though the observations have been made almost for similar type of constructions and lifetime of the houses, but as the volume of the room increases the concentrations drops exponentially and it becomes almost constant above 200 m³. The variation in the concentration follows the exponential drop with the regression coefficients greater than 0.91. The present work reveals that the dwellers of lower volume houses will expose themselves to the higher dose rates and is 4.4 times of the dose received in higher volume houses. The volumetric variations of ²²²Rn, ²²⁰Rn and their progeny levels along with their doses in dwellings of various locations are discussed.

6 illus, 15 ref

006363   Sandeep;Ghimire M P;Deka D;Rai D P;Shankar A; Thapa R K (Physics Dep, Mizoram Univ, Tanhril, Aizawl-796 0009, Email: r.k.thapa@gmail.com) : Magnetic and electronic properties of half-metallic NiTbSb: a first principles study. Indian J Phys 2012, 86(4), 301-5.

The electronic band structures, density of states (DOS) and the magnetic moments have been compared and analyzed to propose the half-metal ferromagnetic nature of NiTbSb. For this, density functional theory based full potential linearized augmented plane wave method has been used. DOS and band structure results show that 3d states of Ni and 4f states of Tb atoms overlap each other throughout the Ni-3d bands, suggesting substantial hybridization between them. The presence of Sb atom influences the hybridization between Ni and Tb atoms. A qualitative agreement with the earlier results has been observed.

4 illus, 2 tables, 24 ref

006362   Rao S M (Civil Engineering Dep, Indian Institute of Science, Bangalore-560 012, Email: msrao@civil.iisc.ernet.in ) : Reverse osmosis. Resonance 2011, 16(12), 1333-6.

Osmosis is a phenomenon which regulates many biological functions in plants and animals. That the plants stand upright, or the water reaches the tip of every leaf of a plant is due to osmotic pressure. The fact that we cannot survive by drinking seawater is also linked to this same phenomenon. J H van't Hoff showed in 1886 that osmotic pressure is related to concentration and temperature of the solution by a law that is similar to the gas law. An understanding of this phenomenon paved the way not only in explaining the biological functions which depend on osmosis, but also in creating conditions for reversing it known as 'reverse osmosis'. Reverse osmosis has many applications, one of which is desalination of seawater. The inaugural Nobel Prize in Chemistry was awarded in 1901 to van't Hoff for his seminal work in this area. The present article explains the principle of osmosis and reverse osmosis.

1 illus, 1 table, 3 ref

006361   Pop N C;Caltun O F (NO, Faculty of Physics and Carpath Center, Alexandru Ioan Cuza Univ, Iasi-700 506, Romania, Email: popnicusor@yahoo.com) : Using the Jiles-Atherton model to analyze the magnetic properties of magnetoelectric materials: (BaTiO₃)_x (CoFe₂O₄)_1-x. Indian J Phys 2012, 86(4), 283-9.

In this paper Jiles-Atherton (J-A) model has been implemented in order to simulate the magnetic hysteresis loops of magnetoelectric composite samples containing cobalt ferrite and barium titanate ((BaTiO₃)_x(CoFe₂O₄)_1-x having x = 0.8, 0.6, and 0.4) sintered at four temperatures 1,000 °C, 1,050 °C, 1,100 °C, and 1,150 °C. In each case the J-A parameters are calculated. The dynamic of these parameters has been correlated with the microstructure of the samples and the ratio of the concentrations of the two phases (magnetostrictive/piezoelectric). Concomitantly with it the remanent magnetization, the saturation magnetization and the coercive field's dependences on the magnetic phase's concentration have been studied. The dependence of the J-A model parameters on sintering temperature have been analyzed.

5 illus, 5 tables, 23 ref

006360   Najam L A;Jamil N Y;Yousif R M (Physics Dep, College of Science Mosul Univ, Nineveh 00964, Iraq, Email: da_laithahmed@yahoo.com) : Fabrication of CdMnTe semiconductor as radiation detector. Indian J Phys 2012, 86(4), 267-72.

In this work, devices have been fabricated as to be nuclear detector, from p-CdMnTe. Three devices were prepared: First planar detector with (Au) ohmic contact on both sides; Second as schottky type device of In-CdMnTe with (Au) ohmic contact on the back face; and thirdly metal oxide semiconductor (MOS) device for which the samples annealed under Oxygen flow for (2 h.) at 700 °C, this device (MOS) when connected to conventional nuclear spectroscopy gave reasonable but not high quality signals due to irradiating with ¹³⁷Cs, ²⁴¹ Am and (¹³⁷Cs + ²⁴¹Am). Matlab- software based on numerical methods is used to analyze the data. Resolution through the Full Width at Half Maximum and the area under the peak and the error for this detector are presented.

14 illus, 1 table, 14 ref

006359   Mishra B N;Mishra A P (Physics Dep, Millennium Institute of Technology & Science, Bhopal-462 002, Email: byasnarayanmishra@rediff.com) : Peculiar behaviour of solar cycle-23 in comparison to previous solar cycles. Indian J Phys 2012, 86(4), 253-8.

The abrupt decrease in cosmic ray intensity and disturbances in geomagnetic field are known as Forbush decreases (FDs) and Geomagnetic storms (GSs) respectively. Author selected the number of FDs and GSs during solar cycles 20-23. It is found that the occurrence of FDs follows the sunspot cycle 23, whereas the occurrence of GSs does not follow the sunspot cycle during the descending phase of solar cycle 23. The event of FDs has been observed to occur more in odd solar cycles in comparison to even solar cycles which show the even-odd asymmetry, whereas the occurrence of GSs increases with the progress of solar cycles from cycle 20-23. Similarly the grouped solar flare (GSF), solar flare index (SFI), bright solar flare and type II solar radio emission are positively correlated with sunspot cycles 20-23 whereas, the halo coronal mass ejections and type IV SREs show their peculiar behaviour in the descending phase of sunspot cycle 23. The occurrence of type IV SREs shows the even-odd asymmetry, whereas type II SREs increases with the progress of solar cycles. The sunspot number, GSF, SFI decreases as the solar cycle progresses from 20 to 23. In the present paper, the contradictory behaviour of FDs and GSs during cycle 23 has been presented in relation to solar parameters.

5 illus, 6 tables, 28 ref

006358   Hirao Y;Kunimatsu S;Hamamoto T (NO, Kobayasi Institute of Physical Research (KIPR), 3-20-41 Higashi-Motomachi, Kokubunji, Tokyo 185-0022, Japan, Email: hirao@kobayasi-riken.or.jp) : Wireless measurement system for ground-borne vibration and vibration amplifications in buildings. MAPAN 2012, 27(4), 231-9.

Environmental impact on residents of buildings, such as adverse effect on sleep and physical discomfort is caused by ground-borne vibration sources such as rail transit systems, road traffic, construction sites, and industrial plants. To estimate the impact of these vibrations on the residents, it is necessary to measure the tri-axial vibrations in the vertical and horizontal directions of the buildings as specified in the international standard regulated by ISO 2631-2:2003. A wireless measurement system for simple and accurate measurement of building vibration was developed. Five wireless vibration measurement devices (installed together with a data recorder in the building) are controlled simultaneously by an outdoor mobile PC or a laboratory PC via wireless local area network and an Internet connection. It sends the vibration acceleration waveforms recorded in buildings over the wider internet communication system to the laboratory PC. The wireless measurement system was used for measuring vibration in two- and three-story detached houses of wooden or steel construction. The impact on the residents may be caused by the vibration amplifications associated with building structural resonances. The vibration amplifications in 120 houses were evaluated as ratios and level differences in 1/3 octave band vibration accelerations measured at the ground near the substructure and floors.

8 illus, 15 ref

006357   Hari Prasad Reddy M;Sreedhar A;Uthanna S (Physics Dep, Sri Venkateswara Univ, Tirupati-517 502, Email: hari.phys@gmail.com) : Structural, surface morphological and optical properties of nanocrystalline Cu₂O films prepared by RF magnetron sputtering: substrate bias effect. Indian J Phys 2012, 86(4), 291-5.

Cuprous oxide films have been prepared on glass substrates by sputtering of metallic copper target in an oxygen partial pressure of 2 x 10^-2 Pa under different substrate bias voltages in the 0 to -100 V range employing RF magnetron sputtering technique. The influence of substrate bias voltage on the structural, surface morphological, electrical and optical properties has been studied systematically. The crystallite size of the films increases with the increase of substrate bias voltage up to -60 V. The films formed at substrate bias voltage of -60 V show low electrical resistivity of 12 Ω cm, larger crystallite size of 35 nm and optical band gap of 2.40 eV.

5 illus, 1 table, 37 ref

006356   Goyal S L;Kishore N (Applied Physics Dep, Guru Jambheshwar Science & Technology Univ, Hisar-125 001, Email: goyalsneh@yahoo.com) : Systematics for the cross-sections of the (n,p) reaction at 14.5 MeV neutron energy. Indian J Phys 2012, 86(4), 317-21.

New empirical formulae for the calculation of the (n, p) reaction cross-sections at 14.5 MeV neutron energy has been proposed. The measured data for (n, p) reaction cross-sections have been collected from the literature and analyzed for the isotopes having 3 ≤ Z ≤ 83. It has been found that σ_n,p versus Z/A is more effective than σ_n,p versus S_p The odd-even effects have been observed as the cross-sections of odd-mass nuclei are higher than those of their neighboring even-even nuclei.

4 illus, 27 ref

006355   Gorai S K;Mahto P (Physics Dep, Tata College, Chaibasa, West Singhbhum-825 301, Email: s_gorai@yahoo.com) : Plasmon energy and lattice energy of binary tetrahedral semiconductors and I-VII ionic compounds. Indian J Phys 2012, 86(4), 273-7.

Two simple empirical relations have been proposed to estimate lattice energy from plasmon energy and bond length of binary tetrahedral semiconductors A^NB^8-N and I-VII ionic solids. The estimated values are in excellent agreement with the experimental and reported values. Attempt has been made to give a physical basis of the proposed correlation it has been shown that the constants appearing in the proposed relation are characteristics of crystal structures. Effects of atomic size, coordination and ionicity on the lattice energy have also been discussed.

2 illus, 3 tables, 32 ref

006354   Garg N;Sharma O (Acoustic Ultrasonic and Vibration Standards, Apex Level Standards and Industrial Metrology Group CSIR-National Phys, Dr K S Krishnan Marg, New Delhi-110 012, Email: ngarg@mail.nplindia.ernet.in) : Measurement accuracy of secondary standards of sound pressure in comparison to primary standards. MAPAN 2012, 27(4), 219-29.

Paper presents the measurement uncertainty achieved in realizing the primary standard of sound pressure at NPL, India and comparison of the uncertainties of secondary calibrations with that of primary standard. The uncertainty associated with calibration of acoustic calibrators, working standard microphones and sound pressure level measurements is discussed. A comparison of the actuator response with that taken from reciprocity setup for. working standard microphones is also presented. The major focus of the present work is to highlight the traceability chain established in measurement of sound pressure level and propagation of measurement uncertainties directly from the national primary standard to field measurements, which are very rigorously conducted in transportation noise monitoring, machinery noise diagnostics, noise labeling of electrical appliances and environmental impact assessment studies w.r.t noise abatement and control.

7 illus, 5 tables, 30 ref

006353   Fan Q;Sun W;Li H;Feng H (School of Physics and Chemistry Research Centre for Advanced Computati, Xihua Univ, Chengdu-610 039, Sichuan, People's Republic of China, Email: weiguosum@x263.net) : Rovibrational energies in the ground state of nitrogen molecule using an algebric approach. Indian J Phys 2012, 86(4), 237-43.

Algebraic Method (AMr) is used to evaluate rotational spectrum constants and energies using a known accurate experimental/theoretical rovibrational energy subset of a given rovibrational band for a diatomic electronic state. The AMr has been applied to study the rovibrational energies up to j = 40 in vibrational bands from v = 0 to 8 of X¹ Σ⁺_g electronic state of N2 molecule. Calculations show that (i) the AMr not only reproduces the accurate experimental/ theoretical energies, but also generates rotational constants and the E_vj 's of high-lying rovibtational excited states; (ii) The accuracies of the rotational spectrum constants and energies are uniquely determined by the quality of the input experimental/theoretical data.

2 tables, 21 ref

006352   Devi S;Jha A K (Thin Film and Materials Science Laboratory, Applied Physics Dep, Delhi Technological (Formerly Delhi College of Engineering) Univ, Bawana Road, Delhi-110 042, Email: dr_jha_ak@yahoo.co.in) : Enhancement of piezoelectric and ferroelectric properties n wolframium substituted barium titanate ferroelectric ceramics. Indian J Phys 2012, 86(4), 279-82.

Tungsten substituted samples of composition Ba (Ti_1-x W_x) O_3+δ are synthesized by solid-state reaction method. The prepared samples are characterized for their structural and electrical properties. X-ray analysis confirms the formation of single-phase perovskite structure. The microstructural studies reveal that the average grain size increases with increase in wolframium content. An increase in remanent polarization with increasing concentration of W has been observed. The maximum observed value of remanent polarization (P_r) is nearly 2.67 μC/cm² in the sample with x - 0.30. The maximum d₃₃ value is found to be 112.8 pC/N in the sample with x = 0.15.

4 illus, 28 ref

005380   Tangsrirat W;Channumsin O;Pukkalanun T (Faculty of Engineering, King Mongkut's Institute of Technology Ladkrabang (KMITL), Chalongkrung Road, Ladkrabang, Bangkok-10520, Thailand, Email: drworapong@yahoo.com) : Universal voltage-mode SIFO-type biquad with fully MOS-C realization using DDCCTAs. Indian J pure appl Phys 2013, 51(7), 516-22.

An electronically tunable universal voltage-mode biquad filter which is based on using the newly introduced active building block, namely differential difference current conveyor transconductance amplifier (DDCCTA) is presented in the present paper. The proposed circuit having single input and five output (SIFO) terminals uses two DDCCTAs, two grounded capacitors and two electronic resistors suitable for MOS-C realization. The circuit realizes all the five standard biquadratic filter functions simultaneously without changing circuit topology. In addition, the circuit features the high-input impedance terminal, an electronic control of its natural angular frequency and quality factor. The workability of the proposed circuit has been verified using PSPICE simulations based on CMOS DDCCTA implemented in 0.5 mm MIETEC CMOS technology.

13 illus, 26 ref

005379   Sharma S K;Sharma B S;Kumar R (Physics Dep, Shivalik Institute of Engineering and Technology, Aliyaspur, Ambala-133 206, Email: sav31@rediffmail.com) : Anharmonicity in thermal pressure for Aluminium. Indian J pure appl Phys 2013, 51(7), 494-8.

An expression for the volume dependence of thermal pressure is formulated using basic thermodynamic identities. It is applied to aluminium metal for which sufficiently reliable data are available for comparison. The calculations are performed using the two models viz. the Thomas-Fermi model and the Stacey-Davis model. It is found that the values of thermal pressure for m=6 in both models are almost the same. Thermal pressure increases with the increase in pressure. The anhormonic effects are found to be dominant below about (P=60 GPa). While above this, harmonic effects become dominant. The anharmonic effects are very important at low pressures and become less significant as the pressure is increased. Values of thermal pressure have been calculated by taking into account the effect of the change in volume on melting. The results obtained for aluminium indicate that the present model is capable of predicting the volume dependence of thermal pressure, which is found to be in good agreement with the available data for a wide range of pressures and temperatures.

2 illus, 33 ref

005378   Sharma M (Physics Dep, Institute of Engineering and Technology, Alwar, Rajasthan, Email: megha.sharma883@gmail.com) : Design details of novel lightweight low cost solar cooker and its experimental study. Int J latest Technol Engng Mgmt appl Sci 2013, 2(1), 65-74.

World is facing severe energy crises and the mode of conversion of various fuels into utilizable form affect economy, environment and health adversely. Utilization of renewable energy resources particularly solar energy can decrease these to a considerable extent. Solar energy is most promising renewable source for India and all underdeveloped and developing nations which within 40? of equator. Solar energy can be utilized in both direct and indirect form. Utilization of solar energy in the form of solar thermal applications can save a lot of conventional energy resources. In country like India on the one hand solar cooking needs to be promoted while on the other hand there is a need for development of more efficient and user friendly solar cookers. Solar cooking would be popularized only when a good number of models are made available to the masses with appropriate characterizations and performance figures clearly mentioned for each model. Therefore a uniform strict test protocol must be followed for solar cookers. Only then users will have correct choice and would be attracted for maximum use of solar cookers. With this view authors have discussed at length various test protocols. With study of L.S.C. clearly reveals that the cooker design developed and studied in the present work has good weather ability, life, thermal performance and cooking performance.

3 illus, 4 tables, 10 ref

005377   Poorreza E;Vafaie R H;Mehdipoor M;Pourmand A; Ghavifekr H B (Faculty of Electrical Engineering, Sahand University of Technology, Tabriz, Iran) : Microseparator based-on 4-phase travelling wave dielectrophoresis for lab-on-a-chip applications. Indian J pure appl Phys 2013, 51(7), 506-15.

Separation of micron-sized particles is a challenge by highly miniaturized channel systems. In order to offer the ability of smaller volumes and high throughput in Lab-on-a-chip devices more miniaturized components are needed. Due to very low Reynolds number of buffer fluid, microseparators based on travelling wave dielectrophoresis effect have a good efficiency in such applications. In the present paper, a microchannel technique based on surface micromachining is modified to a microseparator. The proposed device is a miniaturized 4-phase travelling wave microseparator with the height of 5 æm, which can be used for separation of biological particles such as cells and some types of viruses. According to numerical simulations, the device can separate and sort different species, as well as different sized cells of the same species. Due to fabrication process, the electrodes made of highly doped poly-silicon are covered by a thin silicon-nitride layer. Additional advantage of the silicon-nitride layer over electrode arrays is the prevention of high electric field gradient. The effect of this thin insulating layer on functionality of the microseparator has been investigated. The simulation results show that a good separation occurs in the frequency range of 1MHz, when electrical conductivity of buffer fluid is near 1æs/m. The fabrication process is presented and influences of other parameters such as permittivity of fluid and fluid conductivity on the operation of the separator are discussed.

13 illus, 1 table, 36 ref

005376   Paras Ram;Ashok Kumar;Singh H (Mathematics Dep, NIT, Kurukshetra, Haryana) : Effect of porosity on unsteady MHD flow past a semi-infinite moving vertical plate with time dependent suction. Indian J pure appl Phys 2013, 51(7), 461-70.

The effects of porosity on unsteady magnetohydrodynamics (MHD) flow of an electrically-conducting fluid past an exponentially accelerated semi-infinite moving vertical plate with time dependent suction have been studied. A uniform magnetic field is applied perpendicular to the wall. The plate moves with a constant velocity in the direction of fluid flow while the free stream velocity follows an exponentially increasing small perturbation law. The governing equations of motion and energy are transformed into ordinary differential equations using time dependent similarity parameter. These differential equations are then solved numerically using Flex PDE solver. The effects of various physical parameters on velocity and temperature distribution are presented quantitatively and graphically.

16 illus, 20 ref

005375   Osibona A O;Eniola E B (Marine Sciences Dep, University of Lagos, Akoka, Lagos, Nigeria) : Diet composition of four commercially economic important species from Nigerian coastal waters. Asian J Microbiol Biotechnol envir Sci 2011, 13(4), 599-604.

The food and feeding habits of four indigenous commercial fish species, namely Clarias gariepinus, Tilapia zillii, Pentanemus quinquarius and Pseudotolithus typus was investigated. Fish species were procured from fishermen every month. Specimens that were dead on purchased were chilled with iced blocks at the point of collection and transported to the laboratory. A total of 670 fish specimens were examined and their stomach contents analyzed. Frequency of occurrence and numerical methods were employed in this study. The result of analysis showed that 159 (23.73%) of all the species examined had empty stomach. C.gariepinus was found to be an omnivore feeding on insects, plankton and invertebrates, consisting of five families. In T.zillii, planktonic organisms constituted the greater part of the food items found in the stomachs. P.quinquarius and P. typus fed mainly on small fishes and crustaceans. There was no statistical difference in the feeding habits of these four species. Pollutants from the environment on the coastal waters do not affect the feeding habit of the species.

5 tables, 26 ref

005374   Melavanki R M;Patil N R;Sanningannavar F M; Kusanur R A;Nagaraja D;Patil H D;Kadadevarmath J S (Physicss Dep, M S Ramaiah Institute of Technology, Bangalore-560 054) : Solvent effect on fluorescence quenching of biologically active 6-methoxy-4-azidomethyl coumarin by aniline in different solvents. Indian J pure appl Phys 2013, 51(7), 499-505.

Solvent effect of fluorescence quenching of biologically active studies of 6-methoxy-4-azidomethyl coumarin (6MAMC) by aniline in five different solvents namely dioxane, tetrahydrofuran, dichloroethane, dimethylformamide and acetonitrile has been carried out at room temperature with a view to understand the quenching mechanisms. The Stern-Volmer (S-V) plot has been found to be non-linear with a positive deviation for all the solvents studied. In order to interpret these results, we have invoked the ground state complex formation and sphere of action static quenching models. Using these models, various quenching rate parameters have been determined. The magnitudes of these parameters suggest that sphere of action static quenching model agrees well with the experimental results. Hence, the positive deviation is attributed to the static and dynamic quenching. Further, with the use of Finite Sink approximation model, it was possible to check these bimolecular reactions as diffusion-limited and to estimate independently distance parameter R' and mutual diffusion coefficient D. Finally, an effort has been made to correlate the values of R' and D with the values of the encounter distance R and the mutual coefficient D determined using the Edward's empirical relation and Stokes-Einstein relation.

5 illus, 3 tables, 24 ref

005373   Jain V;Malav H;Jaiman N K;Maheshwari K P (Pure & Applied Physics Dep, University of Kota, Kota-324 010, Email: k_p_maheshwari@rediffmail.com) : Effect of temporal profile of the laser pulse interacting with solid surface on the generation of high harmonics and attosecond pulse trains. Indian J pure appl Phys 2013, 51(7), 479-87.

The effect of temporal profile of an ultra-intense, ultrashort few-cycle laser pulse incident normally on a solid surface on harmonics generation (HHG) and attosecond pulse trains has numerically been studied. The results of transformation of initially narrow spectrum of the laser pulse into a broad harmonic spectrum are obtained. The reflected signal has the form of a train of ultrashort pulses of duration ~100 attoseconds for the case of a Ti:sapphire laser. The effect of collisions on electron dynamics has been taken into account.

24 illus, 17 ref

005372   Ghosh B;Banerjee S;Paul S N (Physics Dep, Jadavpur University, Kolkata-700 032, Email: bsdvghosh@gmail.com) : Effect of non-thermal electrons and warm negative ions on ion-acoustic solitary waves in multi-component drifting plasma. Indian J pure appl Phys 2013, 51(7), 488-93.

Using the Sagdeev's pseudopotential approach, effects of non-thermal electrons and warm negative ions on the conditions for existence and structure of first and second order ion-acoustic solitary waves have been investigated in a multi-component drifting plasma. It is shown that there exists a critical concentration of negative ions which decides the existence and nature of the ion-acoustic solitary waves. It is found that the non-thermal electrons, the concentration of negative ions and the temperature of negative ions have significant contributions towards the excitation and structure of the ion-acoustic solitary waves. The plasma under consideration can support the formation of compressive, rarefactive as well as W-type solitons with certain restricted values of plasma parameters. The results are important in the context of ionospheric and magnetospheric plasmas.

5 illus, 30 ref

005371   Genwa M;Chopra V S (Chemistry Dep, Deen Dayal Upadhyaya College (University of Delhi), Shivaji Marg, Karampura New-Delhi, Email: Vschemistry86@gmail.com) : Alternative energy - solar energy. Int J latest Technol Engng Mgmt appl Sci 2013, 2(3), 128-30.

Solar Energy is the energy received from the sun that sustains life on earth. For many decades solar energy has been considered as a huge source of energy and also an economical source of energy because it is freely available. However, it is only now after years of research that technology has made it possible to harness solar energy. A few industries have increased in size dramatically over a relatively short period. The computer trade is an obvious one and now so is the solar energy trade. New manufacturers are appearing almost daily, new product innovations are announced just as fast, and existing products are ever more refined, improved, and lowered in price. It's an exciting time for the people involved in the various solar energy industries, and this heightened focus translates to better deals for the consumer, whether residential, commercial, government or other. Some of the modern Solar Energy systems consist of magnifying glasses along with pipes filled with fluid. These systems consist of frontal glass that focuses the sun's light onto the pipes. The fluid present in the pipes heats up instantly. In addition they pipes are painted black on the outside so as to absorb maximum amount of heat. The pipes have reflective silver surface on the back that reflects the sunlight back, thus heating the pipes further. This reflective silver surface also helps in protecting everything that is on the back of the solar panel.

1 illus, 6 ref