IOSR-JAP   Volume-6 ~ Issue-6 ~ Nov-Dec 2014

ABSTRACT: In this paper we report a study on acoustic properties of coir mats –a biofibremat of various weaving patterns. In this study coir-mat has been introduced as one of the sound absorbing materials.There are many advantages of coconut fibres because they are moth-proof,non-hazardous,resistant to fungi and ecofriendly with good sound absorption.The study reveals the effectiveness of coir mats as sound absorber and its applications in building acoustics and automotive applications . Coir mats of different weaving were selected for the study viz;Panama, Herringbone, Boucle weaving,mesh matting,Twill weave matting,Diamond weave matting,PVC tufted mat,Lovers Knot,VC2 mat etc.The experiment is performed on an impedance tube apparatus as per ASTM E 1050/ISO 10534-2. The experimental analysis is made for the frequency range 100 Hz-6300 Hz.The results reveal that the mats show good sound absorption coefficient at high frequencies and also the mats with latex backing and increased thickness exhibit appreciable absorption of coir mats. Keywords: coir mats,panama weave,Herringbone weave,Boucle weave mesh matting,Twill weave matting,Diamond weave matting,PVC tufted mat,Lovers knot,VC2 mat,Absorption coefficient,NRC,boimats,biofibre

[1]. Jinkyo, L., and G.W. Swenson, Noise Control Eng 38(3), 109 (1992).
[2]. Wambua, P., J., Ivens, and I. Verpoest, Compos Sci Technol 63, 1259 (2003).
[3]. Joshi, S.V., L.T., Drzal, A.K., Mohanty, and S. Arora, Compos Part A-Appl S 35, 371 (2004).
[4]. Yang, H.S., D.J., Kim, and H.J. Kim, 86, 117 (2003).
[5]. Rozli Zulkifli, et al science publications,sciences,7(2):260-264,2010 ISSN 1546-9239
[6]. Mohd J.M.Nor,et al American journal of Applied sciences,volume7,issue9,page 1285-1290

ABSTRACT: GaAs:Zn films with different thickness (0.25, 0.5, 0.75 and 1.0) μm have been prepared by flash evaporation technique on glass substrate at substrate room temperature under vacuum of 10-5 mbar. These films have been annealed at different annealing temperatures Ta (373and 473) K. The d.c. conductivity for all deposited films decreases with increases of annealing temperatures. The electrical activation energies (Ea1and Ea2) increase with increasing of annealing temperatures. Hall measurements showed that all the films are p-type with carrier's concentration increase with thickness increase and decreases from with increasing of annealing temperature from RT to 473K. Also we observe that the mobility increase with increasing of annealing temperature and decreasing with thickness. the structural characteristic of GaAs:Zn have been studied by using X-ray diffraction which show that the films have amorphous structure for sample annealed at Ta> 473K.The samples were annealed at 473 K showed a polycrystalline with Face-center cubic system preferred orientation along (111).

[1]. Vuraftman, J.R. Meyer and L.R.Ram.Mohan, Journal of Applied Physics, Vol.89, No.11,(2001).
[2]. A. Gheorgihu, T. Rappeneau, S.Fisson and M.L.Theye, Thin Solid Films, 120, (1984) 191-104.
[3]. K.L. Narasimhan, S. Guha, Journal of non-crystalline solids, 16 (1974) 134-147.
[4]. K. Aguir, M. Hadido, P. Lauque, B. Despax, Journal of non-crystalline solids, 113 (1989) 231-238
[5]. M. Balkaniski, R. F. Wallis, Semiconductor Physics and Applications, Oxford University presses, 2000.

ABSTRACT: Nanoparticles of magnetite were synthesized usingaqueous chlorides solutions via coprecipitation technique. The structure and crystallite size of the precipitate were inspected and analyzedregarding X-ray diffraction. Cation distribution of magnetite of the form (Fe3+(2-x) Fe2+y) {Fe2+(1-y) Fe3+x}has been proved and optimized where the cation parameters X and ywere determined using the experimental value of magnetite magnetic moment.Spin-Orbit coupling calculations based on density functional theory were applied.Full optimization was considered and the most stable configuration was proffered.The density of states of magnetite was calculated.The inclination of half metallicity of magnetite was scrutinized. DC electrical resistanceofpressed disk shape magnetite nanoparticles was measured at room and elevated temperatures. The results are discussed andanalyzed in terms of DOS and cation distribution.

Key Words: Half metallic, Magnetite, Electrical resistance, Nano-crystals, DOS.

[1]. R. Valenzuela, Magnetic Ceramics, Cambridge Univer. Press (1994).
[2]. E. J. W.Verwey, Nature, 144 (1939) 327.
[3]. F.Walz, J. Phys. Cond. Mat., 14 (2002) R285.
[4]. S. K. Park, T. Ishikawa, and Y. Tokura, Phys. Rev. B 58, 3717.
[5]. J.Tang, M.Myers, K.A.Bosnick, L.E.Brus,J.Phys. Chem B,107, 7501(2003).
[6]. K. Jordan, et al. Phys. Rev. B 74, 085416, (2006).

ABSTRACT: In this study, a modified Angstrom model for the estimation of global solar radiation in Kano, Nigeria using maximum/minimum temperature and relative humidity based on meteorological data were used. Two new models were developed for estimating the monthly-average daily global solar radiation. Regression coefficients a and b of(1.2577,−1.0167 ) and( 0.8317 ,−0.0043) were obtained from the models based on temperature ratios and relative humidity respectively. In order to evaluate the results, three statistical methods have been used namely; Mean bias, root mean square, and mean percentage errors. The temperature based models which has a lower root mean square error is an indication of good agreement between the measured and estimated global solar radiation. Base on the statistical results a new temperature base model is recommended to estimate monthly global solar radiation for Kano state and other locations with similar climate conditions where the radiation data is unavailable.

Keywords: clearness index, day length, global solar radiation, extraterrestrial radiation

[1]. Nwokoye A. O. C., Solar energy technology: Other alternative energy resources and environmentalsciences (Rexcharles and Patriclimited, Nigeria, 2006).
[2]. Augustine C. and Nnabuchi M. N.,Correlation between sunshine hour and global solar radiation in Warri, Nigeria, Pacific Journal of Science and Technology,10(2), 2009, 574-579.
[3]. B. C. Isikwue, A. N. Amah, and P. O. Agada,Empirical models for the estimation of global solar radiation in Makurdi, Nigeria,GlobalJournal of Science Frontier Research,12(1):2012, 59-61.
[4]. NamrataK., S. P. Sharma, and S. B. L. Saksena, Estimation of global and diffuse solar radiation for Jamshedpur, India, International Journal of Science and Technology, 2(1): 2012, 44-47.
[5]. E. O. Falayi, J. O. Adepitan, and A. B. Rabiu, Empirical models for the correlation of global solar radiation with meteorological data for Iseyin, Nigeria,Pacific Journal of Science and Technology, 9(2),2008, 583-591.

ABSTRACT: A one-reflector solar oven for solar panel lamination was constructed using locally available and low cost materials. The oven was tested for thermal performance through three tests. The first test was a no load test with the oven positioned to face 1800S. This test produced a maximum oven laminating platen temperature of 1180C at an ambient temperature of 330C and solar irradiance of 1046W/m2. A second no-load test was carried out with the oven being turned every 30 minutes to face the sun through a method which we discovered and termed manual shadow tracking. Manual shadow tracking is a method of turning a box type solar oven to face the sun by aligning the bottom edge of the oven with the edge of the oven's shadow. The second no-load test produced a maximum temperature of 1240C at an ambient temperature of 360C and solar irradiance of 1010W/m2. With these values, the first figure of merit for the oven was calculated as 0.09. A third test which was carried out with the oven loaded with a solar panel to be laminated, produced a maximum temperature of 110.50C at an ambient temperature of 350C and solar irradiance of 1021W/m2. A 160W solar panel was laminated with the oven.

Keywords: solar oven, solar panel, solar irradiance, lamination, shadow tracking

[1].J.Viegas,Mammothsroastedinprehistoricbarbecue pit. MSNBC", http://www.nbcnews.com/id/31085915/ns/technology_and_science-science/t/mammoths-roasted-prehistoric-barbecue-pit/, 2009. Retrieved: 03-07-2014.

[2]. K. Petri, "Solar cooker for use in Namibia", MSc Thesis, Faculty of Mechanical Engineering, Helsinki Universityof Technology. http://solarcooking.org/research/fi/petri.htm, 1995. Retrieved: 03-07- 2014.

[3]. D. Y. Dahiru, U. Samaila, and D. Habou, "Performance evaluation of a concentrating solar cooker under hazy weather condition", Continental J. Engineering Science, Wilolud Online Journals, 1, 36- 44, 2007.
[4]. D. A. Pelemo, M. K. Fassi, S. A. Owolabi, and J. A. Shaniyi, "Effective utilization of solar energy for cooking", Nigerian Journal of Engineering Management. 3(1), 13-18, 2002.
[5]. S. C. Mullick, T. C. Kandpal, and A. K. Saxena, "Thermal test procedure for box-type solar cooker", Solar energy, 39(4), 353-360, 1987.

ABSTRACT: Cd-ZnO thin films are prepared by Silar and are characterized by XRD, SEM and EDX. The samples are then placed inside a gas chamber kept at rotary vacuum and at pressure and temperature of 0.20 mb and 3500C. Ethanol vapour is admitted in a controlled manner into the chamber. Resistance of the film is measured continuously before, during and after the admittance of Ethanol vapour. The experiment is repeated for different doping concentrations of Cd. And it has been observed that the resistance of the film reduces fast and considerably at the admittance of Ethanol. The response time was found to be one second and it has been noted that recovery time of the films varies with doping concentrations. Key words: ZnO, Response time, Silar, Ethanol Sensor

[1] Mithra P, Mukopadhyaya A K, Bullettin of Polish Academy of Sciences.2007 3 55

[2] Chandramohan R, Dhanasekharan V, j Mter Sci, Mater Electron. 2012 3 390 [3] Shelke Vrushali, Sonawane B K, Bhole M P, Patil Das, J Matter Sci, Mater Electron. 2012 3 451

[4] Joseph Mathew, Tabata Hitoshi Jpn. J. Appl. Phy. 1999 38

[5] Vijayan T A, Chandramohan R, J. Mater Science. 2008 43 1776

[6] Mcaleer J F, Mosely P T, Tin Oxide gas sensor, J Chem Faraday trans. 1987 183 1323

[7] Lupan O, Materials research bulletin. 2006 10 1016 [8] Schiurbaum K D, Kirner U K, Geiger J F, Gopel W, Sensors and actuators 1991 B5 7

[9] Chandramohan R, Dhanasekharan V, Ezhilvizhiyan S, Vijayan T A, Matter Sci Mater Electron 2012 23 390

[10] Kroger F A, Schok R N, American Geophysical UnionWashington. 1985 1

ABSTRACT: In this paper an extended version of a new universal formula of the rotation velocity distribution of galaxies and a new formula of the energy density distribution of galaxies are presented.They are based on a relativistic invariant LaPlace wave equation where it has been possible to obtain expressions for the rotation velocity - and energy density distributions versus distance to the galactic centre. Several mathematical proofs of these new formulas are also given. These formulas are divided into a Keplerian (general relativity)-and a relativistic (special relativity) part.

[1]. Freeman, K. C. ,(1970), Ap. J.,160 , 811
[2]. Rubin, V. C., Ford, W. K., (1970), Ap, J. 150 , 379
[3]. Combes, F., Boisse`,P., Mazure ,A. and Blanchard, A., Galaxies and Cosmology,(2001)
[4]. Barrera,T.,Thelin,B.,IOSR Journal of Applied Physics (IOSR-JAP) Vol 3 (4) p.44 (2013)
[5]. Schwarzschild, K., (1916),Sitz. Acad. Wiss., Physik-Math., Kl. 1 , 189
[6]. Einstein, A., (1916), Ann. Physik, 49, 769

ABSTRACT:The effect of silicon on In GaAsSi/GaAs quantum well structures is investigated using high resolution X-ray diffraction technique (HRXRD) . The growth of quantum well is studied by surface electron microscopy (SEM). The surface morphology is studied using atomic force microscopy (AFM). It is observed from the AFM images that the roughness increases as Si doping increases. The incorporation of silicon also induces alloy non-uniformity in the quantum well, leading to an increased surface roughness. We found that the FWHM of the rocking curves of Si-doped InGaAs increase with increasing Si concentration, indicating the degradation of the crystal quality with increasing doping level.

[1]. L.Survase, M.Nyayate, Sen Mathew; International Journal of Science and Research, vol-3, issue-9,(2014), pp 965-967.
[2]. Ying Wang, Weijin Chen, Biao Wang, Yue Zheng, Materials vol 7 (2014) 7, pp 6377-6485;
[3]. W. Q. Li and P. K. Bhattacharya, S. H. Kwok and R. Merlin, J. Appl. Phys. 72 (7), (1992) pp 3129-34
[4]. Y. Fedoryshyn,M. Beck, P. Kaspar, H. Jaeckel Journal of applied physics 07 (2010) pp 107-110.
[5]. M. Giehler, R. Hey, H. Kostial, S. Cronenberg, T. Ohtsuka, L. Schrottke, H. T. Grahn, Appl. Phys. Lett.82, 2003., pp 671
[6]. X.G. Xu , Ch. Giesen a, J. Xu b, M. Heuken a, K. Heime Journal of Crystal Growth 181 (1997),pp 26-32.
[7]. Mohamed Henini, Elsevier Science, volume 8, No.1 (1995) pp 18-22.

ABSTRACT:Renal scintigraphy can provide the valuable split renal function which is not obtainable by other non-invasive measurements. Whole body bone scintigraphy (bone scan) using a 99mTc-labelled pharmaceutical is one of the most commonly performed radionuclide examinations. Both the osseous components of the skeletal system as well as the kidneys and bladder are visualized.

[1]. (Buckley, Orla a; O'Keeffe, Sylvia a; Geoghegan, Tony a; Lyburn, Ian D. b; Munk, Peter L. c; Worsley, Dan c; Torreggiani, William C. a, Nuclear Medicine Communications. 28(7):521-527, July 2007).
[2]. (Khalil et al, Comparative Study Between99mTc-MDP and 99mTc-DTPA as a Predictor For RenalFunction ,Australian Journal of Basic & Applied Sciences;Feb2013, Vol. 7 Issue 2, p360,2013)
[3]. (Gates GF. Split renal function testing using 99mTc-DTPA: a rapid technique for determining differential glomerular filtration. Clin Nucl Med 1983; 8: 400-407).
[4]. (Goates et al.,1990.Comparison of methods for calculating glomerular filtration rate: technetium-99m-DTPA scinti-graphic analysis, protein-free and whole-plasma clearance of technetium-99m-DTPA and iodine-125-iothalamate clearance. NucL. Med., 31:424-429.

ABSTRACT:In order to evaluate the effects of liquidity management on the security market performance of companies listed at the Nairobi Securities Exchange, this Census study was carried out on the companies that are listed at the NSE over a 72-month period of January 2008 through December 2013. Using the descriptive research design and the Ordinary Least Squares (OLS) model the study revealed that there is a significant difference between the market performance of liquid companies and that of the illiquid companies, with quick ratio as the measure of liquidity management

[1]. A. Eljelly, Liquidity-Profitability Tradeoff: An Empirical Investigation in an Emerging Market, International Journal of Commerce & Management.14 (2), 2004, 48-61.
[2]. I. Lazaridis and D. Tryfonidis, Relationship between working capital management and profitability of listed companies in Athens stock Exchange. A journal of financial management and Analysis, 19(1), 2006, 26-35.
[3 &4] A. Bhunia, A trend analysis of liquidity management efficiency in selected private sector Indian steel industry, International Journal of Research in Commerce and Management, 1 (5), 2010, 213.
[5] A. N. Berger, and C. H. Bouwman, Financial Crisis and Bank Liquidity Creation, Retrieved December 2013, from Social Science Research Network: http://ssrn.com/abstract=1231562, 2008. [6] G. Amarjit, B. Nahum and M. Neil, The Relationship between Working Capital Management and Profitability: Evidence from the United States, Business and Economics Journal, BEJ-10, 2010. [7] K. Priya, and B. Malathasan, Liquidity management and profitability: A case study of listed manufacturing companies in Sri Lanka, International Journal of Commerce & Management, 2013.