Vol. 8 & Issue 2 ; Section C : Physical Sciences

Date : Feb. to April 2018

 

DSC and TGA Properties of PVA Films Filled with Na2S2O3.5H2O Salt

Sabah A. Salman, Nabeel A. Bakr, Hudaa T. Homad

[DOI: 10.24214/jcbps.C.8.2.00111]

  • Abstract

    Pure and sodium thiosulphate pentahydrate (Na2S2O3.5H2O) salt filled polyvinyl alcohol (PVA) films with different concentrations of (2, 4, 6, 8, 10, 12, 14, and16 ) wt % were prepared by solution casting method to study the effect of this salt on thermal properties of  (PVA) films by using Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). The DSC test showed that most of the samples filled with (Na2S2O3.5H2O) salt exhibit an increase in the glass transition temperature compared with pure PVA film, while melting point had unsystematic dependence on the (Na2S2O3.5H2O) salt concentration compared with pure PVA film. Moreover, TGA curves indicated that the pure PVA film underwent two stages of thermal decomposition of the weight loss while (Na2S2O3.5H2O) salt filled PVA films had two and three stages of thermal decomposition of the weight loss process where the values of total weight loss of the films are lower compared with pure PVA film

A theoretical study of Quantum well intermixing in GaInNAs/GaAs structure and evaluation of transition energies as a function of diffusion length and evaluation of dipole moments of TE and TM polarization as a function of wave vector A0-1.

Supriya Kumari, P. K. Verma and L. K. Mishra

[DOI: 10.24214/jcbps.C.8.2.01225.]

  • Abstract

    Using the theoretical formalism of H D Sun etal [J. of Appl. Phys. 94, 7581 (2003)], A. Mika etal. [Optica Applicata Vol XLIII, No1 (2013)] and Y. N. Qiu etal. [Semicond. Sci. Technol. 23, 095010 (2008)], we have theoretically studied the effect of quantum well intermixing on the material gain of GaInNAs/GaAs quantum well. We have evaluated optical transition oscillator strength and square of the overlap integral as a function of photon energy. Our theoretically obtained results show that oscillator strength increases with photon energy whereas square of the overlap integral for two values of Qc (chemical band offset) increases and decreases with photon energy. Our theoretically evaluated results for optical transition energy for two transition E1-HH1 (electron and heavy-Hole transition) and E1-LH1 (electron and light Hole) increase with diffusion length and the results are in good agreement with the experimental data. Our obtained results of dipole moment indicate that with different diffusion lengths the wave function overlapping between electron and heavy/light Holes in terms of TE and TM modes are different. The calculation shows that with the increase of diffusion length the contribution from E1-LH1 transition to dipole moments of TE or TM modes are suppressed very quickly. For contribution to E1-HH1, TE mode decreases slowly but the dipole moment of TM mode increases slightly.The entire evaluation gives the effect of quantum well intermixing on the material gain of GaInNAs/GaAs quantum well. The evaluation confirms that the variation of material band gap and the degeneracy between heavy and light Holes are the main factors which determine the quantized energy levels of intermixed quantum well. These studies will be quite helpful in the design of integrated photonic devices based on this material.

Anharmonicity of Lattice Waves in Electronic Specific Heat of Materials at Very Low Temperature

P. Poddar, A.K. Sah, D.P. Singh & Murari Pd. Sinha

[DOI: 10.24214/jcbps.C.8.2.02635.]

  • Abstract

    In this paper we discuss the role of anharmonicity of lattice waves in electronic specific heat of metals and insulators at very low temperatures. Previous researchers have revealed the anharmonicity of the lattice waves to cause deviation in specific heat from Debye T3 law. Different researchers have given different concepts of anharmonicity in electronic specific heat of metals at very low temperatures. The energy spectrum of phonons cannot be fully described by the Debye law. On the whole all reports dilute the contention of the electronic contribution to be responsible for linear temperature dependent component of specific heat of metals at very low temperatures. For anharmonicity of lattice waves this contribution must be expected for metals and insulators also.

Investigation of the interaction between vitamin C and vitamin B12 with human serum albumin using spectroscopic techniques

Husain Alsamamra, Ibrahim Hawwarin, Sawsan Abusharkh, Musa Abutier

[DOI: 10.24214/jcbps.C.8.2.03653]

  • Abstract

    Vitamin C is an important regulatory for iron uptake and vitamin B12 is essential for proper functioning of folic acid. Human serum albumin is an abundant plasma protein, the major soluble protein constituent of the circulatory system and has many physiological functions including transport of a variety of compounds. In this work, the molecular interaction between vitamin C and B12with human serum albumin was investigated using constant protein concentration and various drug concentrations at pH 7.4. Three different spectroscopic methods were used; fluorescence spectroscopy, UV absorption and FT-IR spectroscopy. From spectral analysis, both vitamins showed a strong ability to quench the intrinsic fluorescence of human serum albumin through a static quenching procedure.The binding constant (k) is estimated from UV-absorption as k=1.28×104 M-1 for HSA-Vitamin C and k=2.21×104 M-1 for HSA-vitamin B12. Both results showed a good agreement with the binding constants obtained from the modified Stern-Volmer equation using florescence technique. The appearance or disappearance of the bands is a good sign to understand the mechanisms at the molecular level. The FT-IR spectral changes indicates an increase of intensity for HSA-vitamin C interaction and a reduction of intensity for HSA-vitamin B12 interaction. For HSA-vitamin C complexes, positive features are related to increase in intensity of the amide I and II bands upon drug-complexation due to drug binding to protein C=O, C-N and N-H groups. While in the  difference spectra of vitamin B12-HSA complexes, intensity decreases as the concentration of vitamin B12 increases for amide I band at 1656cm-1, and amid II band at 1544 cm-1, this results in stabilization by hydrogen bonding by having the C-N bond assuming partial double character due to a flow of electrons from the C=O to the C-N.

Synthesis of CoZnFe2O4 nanoparticles by microwave assisted combustion method and antibacterial properties

Falah M.Abdelhasan, Mukhlis M. Ismail, Nada S. Ahmade

[DOI: 10.24214/jcbps.C.8.2.05467.]

  • Abstract

     In this research work, we have used a microwave combustion method to synthesize cobalt-zinc ferrite (Zn1_xCoxFe2O4) nanoparticles with four nanocrystalline ferrites including: Co1Fe2O4, Co0.9Zn0.1Fe2O4 , Co1.1Zn0.1Fe2O4 and Co 0.3Zn 0.7Fe2O4. Using urea and glycine as a fuel. The obtained ferrites were characterized studied by X-ray powder Diffraction (XRD), results showed that the material had cubic spinal structure. The experimental values of the lattice constant (aexp) were increased from 8.064 to 8.329 nm with the addition of zinc ions but it was decreased with increased cobalt ions. The theoretical values of the calculated lattice constant (ath) were found in a good agreement with the experimental results. It was found that the increased of the crystallite size with addition of zinc but after crystallite size (D) were decreased with increased zinc ion and decreased with decreased cobalt ion. Fourier transform infrared spectroscopy (FT-IR) measurement exhibit two absorption bands (ʋ1 and ʋ2) around 400-600 cm-1 which confirms the existence of tetrahedral and octahedral sites of ferrite. The antibacterial activities of the co-zn-ferrites were tested on Gram-negative bacterium: E. coli. The antibacterial results of the co-zn ferrites nanoparticle on microorganisms showed that the nanoparticles shows effect on the inhibitory growth of E. coli with high antibacterial effect on E. coli  of 3.5 mm diameter of inhibition

Absorption studies in dilute solutions of few amino acids at 662 keV gamma energy

T. Rajeshwari

[DOI: 10.24214/jcbps.C.8.2.06874.]

  • Abstract

    The gamma absorption studies in dilute solutions of amino acids has been carried out using NaI(Tl) scintillation detector coupled with single channel analyzer at 662 keV gamma energy. The mass absorption coefficients of gamma radiation by dilute amino acid solutions are studied for 10 % concentration. The present study explored the validated exponential absorption law for gamma radiation in solutions. A comparison of experimental results with theoretical values revealed the validity of mixture rule. This study proved to be a base study for extension of applications towards investigating the purity of liquid samples and quality control of the liquid materials.

A theoretical evaluation of superfluid density of states (DOS) and pseudogap parameters in BCS-BEC crossover regime of a superfluid Fermi gas

Shipra Kumari, Pradhan Durga Shankar Prasad and L. K. Mishra

[DOI: 10.24214/jcbps.C.8.2.07591]

  • Abstract

    Using the theoretical formalism of Shunji Tsuchiya etal[Phys. Rev A80, 033613 (2009)], Ryota Watanabe etal [Phys. Rev. A82, 043630 (2010)] and Shunji Tsuchiya etal [Phys. Rev. A82, 033629 (2010)], we have theoretically studied the single-particle excitations and strong-coupling effect in the BCS-BEC crossover regime of a super fluid Fermi gas. ........................(See Main article)

Construction and evaluation of electrical properties of a lemon battery

Jakia Sultana, Komor-E-Jahan Dola, Sayed Al Mahmud, Md. Anisur Rahman Mazumder

[DOI: 10.24214/jcbps.C.8.2.09201.]

  • Abstract

    The objective of the research was to develop a lemon battery and determine the electrical properties of lemon battery. The main hypothesis of the research work was to determine whether lemon can produce electricity or not. Lemon has a voltaic cell which changes chemical energy into electrical energy. By a series circuit, conductor (copper) inserted into lemon to generate voltage. Three varieties of lemon such as Kagoji, Sarboti and Elachi were used for the experiments. Elachi could produce maximum 1.0±0.1 v voltage and 1.25±0.05 mA electricity. Overall, the electricity production was very low due to low amount of citric acid in the lemons. However, lemon could produce minimum electricity which might be used in the Light emitting diode (LED).

Expiry date calculations of drugs and cans of foods industry

Talib F. Abbas

[DOI: 10.24214/jcbps.C.8.2.10209.]

  • Abstract

    Shelf life or stability testing is a main part of quality preserve for many foods and drugs. Biopharmaceutical products in storage change as they age, but they are considered to be stable as long as they keep their characteristics within the manufacturer's properties. Thus one can view shelf-life tests as no special category of sensory testing using accepted methods. The objective of the study may dictate what method is most suitable to answer the research questions. Therefore, the Arrhenius equation is the formula of choice to predict the Shelf life. Unfortunately, not all deterioration processes is equally accelerated by an increase in temperature, foods containing high amounts of lipids, pigments and vitamins are highly relevant to deteriorate by light or radiation rather than temperature. In order to facilitate the use of both temperature and light in an ASLT study, the combination of both accelerating factors light and temperature was deduced into one equation. The Arrhenius equation was substituted into the Power Law equation by simply added the regression value of illumination. Alternatively, D&A used the break angles to calculate the predictive values of shelf life in polymer material sterilized by radiation. The experimental protocols used are similar to the protocols used with the Arrhenius equation.The Q10 factor is based on the Arrhenius equation. Statistical tests indicated that the use of this equation was appropriate with some modulation. Shelf-life predictions were also verified by real-time stability testing results.

Fabrication and electrical characterization of solar cells based on poly (o-toluidine), oligothiophene derivatives and nanostructured metal oxide

A. El Mansouri, A. Outzourhit, L. Nkhaili, A. Elkissani, M. Hmeyene, M. Zazoui, H. Ez-zahraouy4, M. Assouag, A. Essamri, A. Elharfi

[DOI: 10.24214/jcbps.C.8.2.11017.]

  • Abstract

    A series of solar cells were fabricated using a nanocomposite based on sexithiophène derivatives and nanostructured zinc oxide as blend donor/acceptor active layer. The polymer (POT) and the oligothiophene were synthesized by chemical oxidization. The powders of nanostructured ZnO were prepared by a one-pot solution route at ambient conditions. The solar cells series were fabricated by successive deposition using the spincoating technic, and they are completed by thermal evaporation of Aluminum circular contacts on active layer. The non-linear dark Current-Voltage I(V) characteristics of these devices indicate the presence of a rectifying behavior. The diode parameters were calculated from the dark I(V) characteristics using the modified Shockley equation. On the other hand, the I(V)characteristics measured under illumination indicate a photovoltaic activity. The solar cells parameters are also studied and compared. The short circuit current (Isc) and the open circuit voltage (Voc) of solar cells are improved by incorporation of the POT thin films as hole-transporting layer.

A theoretical evaluation of Gallium concentration profile and in-plane strain as a function of growth axis z for different diffusion length Ld and study of energy shift (meV) as a function of annealing temperature of GaInNAs/GaAs quantum well laser

Supriya Kumari, P. K. Verma and L. K. Mishra

[DOI: 10.24214/jcbps.C.8.2.11830.]

  • Abstract

    Using the theoretical formalism of H D Sun etal [J. of Appl. Phys. 94, 7581 (2003)], A. Mika etal. [Optica Applicata Vol XLIII, No1 (2013)], Y. N. Qiu etal. [Semicond. Sci. Technol. 23, 095010 (2008)] and S. B. Healy etal. [IEE Proc. Optoelectron, 151, 115505(2004)], we have theoretically evaluated Ga-concentration profile, in-plane compressive strain of GaInNAs/GaAs quantum well as a function of growth direction z for different diffusion length. Our theoretically obtained results show that concentration profile increase and decrease with z for each value of diffusion length whereas in-plane compressive strain changes from zero to negative value with z for each of the diffusion length taken. These results indicate that with the increase of diffusion length the Gallium element in the barrier penetrates further into the quantum well which makes the gradual change of the element concentration between the barrier and the well. Our in-plane strain calculations show that quaternary alloy GaInNAs is less strained than the ternary alloy GaInAs. This is because the lattice constants of GaN and InN are small. The evaluation also gives an indication that due to compressive strain the hydrostatic component widen the band gap and the shear strain component enlarge the splitting between the heavy hole (HH) and the light hole (LH) at band edge k=0. Our theoretically obtained results of intensity of normalized PL-spectra as a function of photon energy for two growth samples, as-grown and PECVD grown show that the PL intensity increase and decrease as photon energy. Our obtained results are in good agreement with compositional analysis of SIMS. We have also analysed the experimental data obtained by group led by H. D. Sun etal regarding the energy shift of GaInNAs/GaAs structure as a function of annealing temperature and also for different N-concentrations. Our analysed results show that PL intensity increase with decrease of N-concentrations. These findings not only rules out the possible mechanism of N-As inter-diffusion but also demonstrates the alloy stability of GaInNAs due to strong bond of In-N. Our all analysed experimental results are in good agreement with the other theoretical workers.The entire evaluation is based on Fick’s law and BAC model with the help of Luttinger-Kohn Hamiltonian. The validity of the model has been confirmed by the excellent agreement with PLE data. The obtained results will be quite useful in the design of integrated photonic devices based on GaInNAs/GaAs material.