IOSR-JAP   Volume-6 ~ Issue-4 ~ July-August 2014

ABSTRACT: The two dimensional Fokker Planck equation is used to describe the time evolution of energetic beam of ions under the effect of dynamical friction and diffusion in velocity space, in a background plasma. The equation is simulated using the Fokker Planck package (FPPAC 81) to obtain the slowing down distribution function for energetic alpha particles which are produced continuously during deuterium-tritium fusion. The effect of varying the temperature for a given injection current which is taken to be a function of the reaction rate of the D-T fusion was studied. It was found that as the temperature increases from 10-20keV, the population of low energy particles decreases while that of high energy particles increases. The slowdown of alpha particles energy with time was faster as the temperature of the plasma increases. The energy increment of the D-T plasma and the electrons as the result of alpha particle heating was computed using the subroutine ENTRNS(k) in the FPPAC. The slowing down of the energetic alpha particle with time and the energy increment given to the plasma was found to be in good comparisons to that of a 180 keV deuterium beam in a 5keV tritium plasma from literature. The energy increment for the plasma deuterium and tritium was found to decrease with temperature due to decrease in dynamical friction as a result of increase in the critical energy 𝑊𝑐.

Key words: Dynamical Friction, Diffusion, Distribution function, Critical Velocity, Injection Current, Reaction Rate.

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ABSTRACT: Amino acids are the building blocks of proteins and an important class of molecules, which are found to exhibit characteristic aggregation patterns in their crystal structures. Especially, the head-to-tail hydrogen bonding patterns that have been observed in the crystal structures of amino acids are of intrinsic interest pertaining to characteristic aggregation patterns. Carboxylic acids are simple organic molecules that are believed to have existed in the prebiotic earth and some of them are key intermediates in the biosynthesis of organic acids. Pyridine is used as a precursor to agrochemicals and pharmaceuticals and is also an important solvent and reagent. Tartaric acid is used as an antioxidant and its derivatives have a plethora of uses in the field of pharmaceuticals. For example, tartaric acid has been used in the production of effervescent salts, in combination with citric acid, in order to improve the taste of oral medications. In the present investigation, the complete vibrational analysis of the title compound is carried out in detail using FTIR and FT Raman measurements.

Keywords: Amino acids, Carboxylic acids, Pyridine, Tartaric acid, Infrared Spectroscopy, Raman Spectroscopy.

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ABSTRACT: Instrumentation for ultrasonic velocity and attenuation measurements in liquids and solids is described. 5 MHz pulse generator is assembled using CMOS integrated circuits (4011, 7414, 74121, and 4010), having pulse width 2 microseconds to 60 microseconds. The wideband receiver is developed using Wideband Low Distortion, High Gain Operational Amplifier (OPA 643). The gain and bandwidth of the receiver are 50 dB and 10 MHz respectively. Transit time measurement has been taken on personal computer using analog to digital converter card. The system is found suitable, accurate and versatile for ultrasonic velocity and attenuation measurements.

Keywords: Instrumentation, Ultrasonic ,Pulse generator, Receiver, Simulation

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ABSTRACT: L-Arginine acetate (LAA) single crystals belonging to the amino acid group are reported to have promising NLO properties. In the present study, to improve further the characteristics of LAA crystals, HCl acid was incorporated into the crystal matrix as a dopant. Single crystals of pure and HCl doped LAA (a total of five) were grown successfully by using the slow evaporation technique. The grown crystals were confirmed chemically and structurally by performing X-ray diffraction (single crystal and powder), CHNS elemental, energy dispersive X-ray spectral and Fourier transform infrared spectral analyses. The crystals are found to be thermally stable up to 204 oC .The UV-Vis spectral analysis shows that these crystals have wide transparency range in the entire visible region. Second harmonic generation (SHG) measurement shows the NLO property. Microhardness measurement indicates that the grown crystals come under soft material category. Dielectric measurements were carried out at various temperatures ranging from 40- 140 ⁰C and with various frequencies such as 1 , 10 and 100 kHz by the parallel plate capacitor method. The AC activation energies were also determined. The temperature and frequency dependences of dielectric parameters observed indicate a normal dielectric behavior for all the five crystals grown in the present study.

Key words: L-arginine acetate, crystal growth, slow evaporation technique, doping effect, physical properties

[1]. Tanusri Pal and Tanusree Kar (2005) Mater. Chem. Phys. 91, 343-347.
[2]. M.Meena and C.K.Mahadevan (2008) Mater. Lett. 62, 3742-3744.
[3]. M.Meena and C.K.Mahadevan (2010) Arch. Appl. Sci. Res.2(6), 185-199.
[4]. M. Gulam Mohamed, M. Vimalan, J.G.M. Jesudurai, J. Madhavan,and P. Sagayaraj(2007) Cryst. Res. Technol. 42, 948-954.
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ABSTRACT: Compression test on glass and carbon fiber epoxy composites tubes were conducted. Effect of tube thickness and fiber type on the load - displacement behavior as well as energy absorption of composites tubes has been investigated. All these parameters found to be effective on the load-displacement behavior and energy absorption capacity of composite tubes. Results obtained from the study shows that, carbon epoxy stands higher load and energy absorption capability than glass epoxy. To simulate the behavior of composite tubes ABAQUS Finite Element Software package was used. Elastic orthotropic material model along with a Hashin Damage model was employed to simulate the load-displacement relations of carbon and glass composite tubes. FE predicted and experimental load displacement curves matched well up to the first failure of the tubes. The FE predicted and experimentally obtained maximum loads were very close. However the FE predicted behavior after the first failure zone deviated from experimental results. The level of deviation was different for each case. Hence FE predicted and experimental energy absorption was not the same.

Keywords: Energy absorption, carbon fiber, glass fiber, composite tubes, Finite element analysis

[1] A. Muhammad and E. Sevkat, Energy Absorption Behavior of Filament Wound Glass and Carbon Epoxies, Proc. 10thInternational fracture conf. Kayseri, Turkey, 2014, 300 – 314.

[2] A. Muhammad, Energy Absorption Behavior of Filament Wound Glass and Carbon Epoxies Composite Tubes, Masters diss., Meliksah University, Turkey, 2014.

[3] S. H. Lee and A. M. Wass, Compressive Response and Failure of Fiber Reinforced Unidirectional Composites, International Journal of Fracture, 100, 1999, 275 - 306.

[4] S. Ocheleski and P. Gotowicki, Experimental Assessment of Energy Absorption Capability of Carbon – epoxy and Glass – epoxy, Composite Structure, 70, 2005, 215 – 224.

[5] S. Palanivelu, W. Paepegem, J. Degrieck, J. Vantomme, D. Kakogiannis, J. Ackeren, D. Hemelrijik and J. Wastiels, Crushing and Energy Absorption Performance of Different Geometrical Shapes of Small – Scale Glass Polyester Composite Tubes under Quasi Static Loading Conditions, Composite Structures, 93, 2011, 992 – 1007.

ABSTRACT: Two-quasiparticle rotational bands of doubly-odd 184Au have been investigated. The two quasiparticle plus rotor model (TQPRM) calculations are done for the bands where sufficient experimental data is available mainly for the ground state band{3/2[532]π  7/2[514]v}and the excited bands with configuration {1/2[660]π  9/2[624]v} and {1/2[541]π  9/2[624]v}. Peculiar features like second point of signature inversion, signature reversal and band crossing are observed in these bands of 184Au. The ambiguity regarding the configuration assignment of ground state band is resolved. The calculations for ground state band clearly show that the proton orbital changes from 3/2[532]π to 1/2[541]π with increasing spin. The mechanism of unusual feature like second point of signature inversion is also presented.

Keywords: Signature inversion, Odd-even staggering, Coriolis coupling, Particle-Particle coupling

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ABSTRACT: Organic halides and other organic compounds that contain electronegative elements, have a strong chemical shift and a brilliant NMR spectrum will prevail. Relationship between 1H, 13C NMR chemical shift and Electronegativity in some simple R-X organic compounds (X=F, Cl, Br, I, O, H, ...R=CH3 or CH3-CH2-) give nonlinear equation, as well as a power series equation appears between nuclear magnetogyric ratio, magnetic shielding constant and chemical shift, which are not included in the theoretical expressions. More investigations required to remove the discrepancy between the theoretical and the experimental results.
Keywords: Electronegativity, chemical shift, shielding constant, magnetogyric ratio.

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