Showing papers in "International Letters of Chemistry, Physics and Astronomy in 2018"

The Gravitational Field in the Relativistic Uniform Model within the Framework of the Covariant Theory of Gravitation

Abstract: For the relativistic uniform system with an invariant mass density the exact expressions are determined for the potentials and strengths of the gravitational field, the energy of particles and fields. It is shown that, as in the classical case for bodies with a constant mass density, in the system with a zero vector potential of the gravitational field, the energy of the particles, associated with the scalar field potential, is twice as large in the absolute value as the energy defined by the tensor invariant of the gravitational field. The problem of inaccuracy of the use of the field’s stress-energy tensors for calculating the system’s mass and energy is considered. The found expressions for the gravitational field strengths inside and outside the system allow us to explain the occurrence of the large-scale structure of the observable Universe, and also to relate the energy density of gravitons in the vacuum field with the limiting mass density inside the proton. Both the Universe and the proton turn out to be relativistic uniform systems with the maximum possible parameters. The described approach allows us to calculate the maximum possible Lorentz factor of the matter particles at the center of the neutron star and at the center of the proton, and also to estimate the radius of action of the strong and ordinary gravitation in cosmological space.

Study of the Interaction of Ciprofloxacin and Sparfloxacin with Biomolecules by Spectral, Electrochemical and Molecular Docking Methods

Abstract: Interactions of ciprofloxacin and sparfloxacin with different biomolecules (DNA, RNA and BSA) are investigated by UV–Visible spectroscopy, fluorescence spectroscopy, cyclic voltammetry and molecular docking methods. Upon increasing the concentration of the biomolecules, the absorption maxima of ciprofloxacin and sparfloxacin are red shifted in the aqueous solutions whereas red or blue shift noticed in the fluorescence spectra. The negative free energy changes suggest that the interaction processes are spontaneous. Cyclic voltammetry results suggested that when the drug concentration is increased, the anodic electrode potential increased. Molecular docking results showed that hydrophobic forces, electrostatic interactions, and hydrogen bonds played vital roles in the interaction drugs with biomolecules. The molecular docking calculation clarifies the binding mode and the binding sites are in good accordance with the experiment results.

A Study of FTIR and some Mechanical Properties of Sodium Iodide (NaI) Salt Filled Polymer Polyvinyl Alcohol (PVA) Films

Abstract: The effect of Sodium Iodide (NaI) salt on mechanical properties of polyvinyl alcohol (PVA) was studied in this work. The interaction between (NaI) salt and polymer (PVA) was investigated by (FTIR) spectroscopy. The effect of (NaI) salt on the mechanical properties of the polymer (PVA) was studied by hardness and tensile tests. FTIR spectra analysis of pure and (NaI) filled (PVA) films showed that the vibrational modes have changed due to the effect of filler salt in the polymer (PVA). Hardness test showed that the hardness increases unsystematically with increasing the weight ratio of added sodium iodide salt except the weight ratio of (16 wt %) compared with pure (PVA) film, while the experimental results of the tensile test for (PVA-NaI) composite films showed unsystematic change of tensile strength, elongation at break and Young's modulus after filling with different weight ratios of (NaI) salt compared with pure (PVA) film. Introduction Polyvinyl alcohol (PVA) has wide applications because of its high dielectric strength, high elasticity, high tensile strength, flexibility, hydrophilic characteristics and its ability to form good films via solution casting [1, 2]. (PVA) is a water soluble synthetic polymer and due to its characteristics of easy preparation, good biodegradability, excellent chemical resistance and good mechanical properties, the polymer (PVA) has been used in many biomaterial applications [3]. (PVA) has a carbon chain backbone with hydroxyl groups that can act as a source of hydrogen bonding to enhance the formation of polymer complexes [1]. The hydroxyl group of (PVA) can also interact with the inorganic compounds. Recently, several types of inorganic metal salts were used as fillers into (PVA) films and a strong effect of these metal salts on the mechanical properties of (PVA) was observed [4]. A significant improvement in mechanical, thermal, optical, electrical, and other properties of polymers can be achieved by adding different inorganic fillers [5]. The fillers are widely used in the plastics industry to cheaply achieve the same levels of performance that would otherwise require much more expensive engineering plastics; also they facilitate surface bonding because the surface of the filler can be easily wetted by a polymer [6]. The study of mechanical properties of polymer matrix composite materials is very important because these properties determine the behavior of the materials under the influence of stress and the influence of various external conditions such as pressure, temperature, time of stress, speed of stress, nature of chemical solvents, and other factors. The study of the mechanical properties is a very complex matter due to the multiple variables affecting each property. Knowing each property would help in selecting the suitable material for a specific practical [7]. Analysis of polymers is one of the most important application fields for (IR) spectroscopy. This type of spectroscopy can be used for the determination of chemical structures, chain conformation, orientation and crystallinity, identification of complex polymeric systems and monitoring reaction processes [8]. In the present work, polymer composite films (PVA-NaI) were synthesized by using solution casting method. The (IR) spectral characterization of composites was carried out by conventional techniques; and some mechanical properties were investigated and compared with the pure (PVA) film. International Letters of Chemistry, Physics and Astronomy Submitted: 2017-12-06 ISSN: 2299-3843, Vol. 78, pp 30-38 Revised: 2018-01-24 doi:10.18052/www.scipress.com/ILCPA.78.30 Accepted: 2018-03-02 2018 SciPress Ltd, Switzerland Online: 2018-04-10 SciPress applies the CC-BY 4.0 license to works we publish: https://creativecommons.org/licenses/by/4.0/ Materials and Methods The polymer (PVA) powder (M.W. = 14000 g/mol) supplied by (Central Drug House Ltd. New Delhi INDIA) and (NaI) salt (M.W. = 149.89 g/mol) supplied by (Modex Germany) were used to prepare (PVA) films with different weight percentages of (NaI) salt (0 %, 4 %, 8 %, 12 %, abd 16 %). The composite films were prepared by dissolving (PVA) powder and (NaI) salt in (15 ml) of distilled water and using magnetic stirrer to mix the solution for (2 hour) at (80 C) to obtain homogeneous solution. The solution then was casted in a glass plate and left to dry to produce film samples. Characterization (a) Fourier transform infrared (FTIR): The infrared spectra of pure and (NaI) filled (PVA) films were measured by using (IR Affinity-1 spectrophotometer) in the range of (400-4000 cm).

Comparative Adsorption of Methylene Blue on Different Low Cost Adsorbents by Continuous Column Process

Abstract: Dyes are commonly found in the effluents of many industries. The effectiveness of adsorption for the removal of dye from wastewaters has been made it an ideal alternative to other expensive treatment methods. Continuous column adsorption is more affective than batch adsorption. A comparative column adsorption study was performed using three different low cost adsorbents for the removal of methylene blue from synthetic wastewater. Sand was collected from Cox’s Bazar, and sugarcane bagasse and used black tea leaves were locally prepared in laboratory. Three columns were designed for different adsorbents maintaining all conditions were to be approximately similar. UV-vis spectroscopic method was used for analysis of methylene blue in solution. Column adsorption experiments were performed to investigate the comparison of breakthrough curves and exhaust capacity of three different adsorbents. Column study shows that the adsorption capacity of used black tea leaves is highest. The adsorption capacity of bagasse is lower than tea leaves but higher than sand. Introduction There is an ever-increasing demand of fabrics and food in the whole world for the rapid expanding population. The wastewaters discharged from dying and printing processes contain high amounts of dissolved colored materials [1]. The disposal of colored wastes such as dyes and pigments into receiving waters damages the environment, as they are carcinogenic and toxic to humans and aquatic life [2, 3]. Besides the problem of color, some dyes impart non-visibility and can be modified biologically to toxic or carcinogenic compounds. Now a day’s concern has increased about the long-term toxic effect of water containing these dissolved pollutants. Methylene blue is commonly used in textile and printing industries. It is moderately to highly toxic by oral and intravenous routes. Eye contact can cause staining of the eye. Inhalations may cause dryness of mouth, flushed skin, rapid pulse, blurred vision, dizziness, etc. [4]. Therefore, proper treatment of wastewater containing methylene blue is essential before its discharge in aquatic system. Different methods are available for the removal of dyes like methylene blue from wastewater but most of them are expensive. Adsorption has received considerable attention for color removal from wastewaters as it offers the most economical and effective treatment methods. Due to high cost of activated carbon, adsorption on natural materials such as sand [5-7], saw dust [8-11], rice husk [10-11], used tea leaves [13-14], coconut coir [15], bagasse [16-17], banana pith [11], fly ash [10-11], orange peel [18] and modified biomaterials [19-21] have received considerable interest because of their local availability and their practically low cost. Use of above biomass materials [821] in batch adsorption process has been found to be highly effective, cheap and eco-friendly. But their proper process of application is very important. This study investigates the potential use of some low cost adsorbents for the removal of methylene blue using column method as a model test. The aim of the study was to compare the adsorption capacity of different low cost adsorbents such as sand, sugarcan bagasse and used black tea leaves, in column adsorption process by constructing breakthrough curves for different column materials using ideal operational conditions and determining their column exhaustive capacity. International Letters of Chemistry, Physics and Astronomy Submitted: 2017-04-04 ISSN: 2299-3843, Vol. 77, pp 26-34 Revised: 2017-12-20 doi:10.18052/www.scipress.com/ILCPA.77.26 Accepted: 2018-01-19 2018 SciPress Ltd, Switzerland Online: 2018-01-25 SciPress applies the CC-BY 4.0 license to works we publish: https://creativecommons.org/licenses/by/4.0/ Materials and Methods Preparation of adsorbent Sand. Sand is cheap and easily available in nature. In this study the sand was collected from Cox’s Bazar, Bangladesh. Figure 1(a) shows the optical view of the collected sand. It was dried well in an oven (NDO-450, EYELA, Japan) at 105 C for 4 hours, crushed and sieved through metallic sieve of mesh size 0.140 mm and screened out. Sugarcane baggase. Sugarcane bagasse (or bagasse) was collected from local market of Dhaka city and washed with boil water to remove the sweet materials. Then it was dried in an oven (NDO-450, EYELA, Japan) at 105 C for 5 hours, crushed and sieved through metallic sieve of mesh size 0.140 mm and screened out. Figure 1(b) shows the optical view of the collected bagasse. Used black tea leaves. Fresh black tea leaves were collected from departmental store in Dhaka city, Bangladesh. Figure 1(c) shows the optical view of the collected Fresh black tea leaves. About 50 g of fresh black tea leaves were boiled in 500 mL of distilled water for 2 hours. Boiled tea leaves were washed 3-4 times with hot distilled water followed by cold distilled water in several times until the tea liquor was completely disappeared. After washing, tea leaves were dried in an oven (NDO-450, EYELA, Japan) at 105 C for 10 hours. Dried used black tea leaves (UBTL) were sieved through the metallic sieve of mesh size 0.140 mm and screened out. Figure 1. Raw materials of adsorbants: (a) sand, (b) sugarcane bagasse and (c) Fresh black tea leaves. Methylene blue and its analysis Methylene blue (MB) is a heterocyclic aromatic compound, also known as methylthioninium chloride. It’s IUPAC name is 3,7-bis(Dimethylamino)-phenothiazin-5-ium chloride, CAS number is 61-73-4, molecular formula C16H18ClN3S and molar mass is 319.85 g∙mol. Synonyms of Methylene blue are Basic blue 9, Swiss blue, Chromosmon, Methylthionine chloride and Urolene blue. Methylene blue is a compound consisting of dark green crystals or crystalline powder, having a bronze-like luster. Solutions in water or alcohol have a deep blue color. Methylene blue is a potent cationic and basic dye with maximum absorption of light around 670 nm. The specificity of absorption depends on a number of factors, including protonation, adsorption to other materials, and metachromasy the formation of dimers and higher-order aggregates depending on concentration and other interactions [22]. Methylene blue can exist as MB, MBH2, (MB)2 and (MB)3 in aqueous solution. Three different forms of structural formula of methylene blue are presented in Fig. 2 [22]. Analytical grade Methylene blue (MB) was collected from Merck Germany. Required amount of dried methylene blue was taken to prepare 10×10 M of stock solution by dissolved in distilled water. Further dilution was made whenever necessary. To construct a calibration curve, the absorbance of different concentrated solutions of MB within the range of 1.0×10 to 4.0×10 M was measured at pH 6.5 by a double beam UV-vis spectrophotometer (UV-160A, Shimadzu, Japan) using λmax = 665 nm. Measured absorbance was plotted against the respective concentration of MB in different solutions to receive the calibration curve. (a) (b) (c) International Letters of Chemistry, Physics and Astronomy Vol. 77 27

Structural and Optical Properties of Thermally Oxidized Zirconium Dioxide Films

Abstract: Zirconium oxide (ZrO2) thin films were grown by thermal oxidation of metallic zirconium films deposited by sputtering of zirconium target by DC magnetron sputtering technique. The zirconium films were thermally oxidized in oxygen atmosphere at temperatures in the range 300-500C. The as-deposited and oxidized films were characterized for chemical composition by energy dispersive X-ray analysis, structure by X-ray diffraction, chemical binding configuration with Fourier transform infrared spectroscopy and optical absorption using UV-Vis NIR spectrophotometer. Metallic zirconium film was polycrystalline in nature with hexagonal structured Zr. The films oxidized at 300C were of mixed phase of Zr and ZrO2. The zirconium films were transformed into monoclinic structured ZrO2 with polycrystalline in nature at oxidation temperature of 400C. Crystallite size of the ZrO2 films increased from 19 nm to 27 nm with increase of oxidation temperature form 400C to 500C. The optical band gap increased from 5.42 eV to 5.46 eV and refractive index decreased from 2.05 to 2.02 with increase of oxidation temperature from 400C to 500C.

Modelling All-Optical Switching and Limiting Properties of AlAs Photonic Crystals

Abstract: The incorporation of defect modes into the perfect crystal structure allows the control of the flow of light by altering the photonic bandgap and thereby can be manipulated to achieve optical switching. A model for all optical switching and limiting based on two dimensional photonic crystals is proposed for AlAs and the performance in square and hexagonal lattice structures were evaluated. Simulations were done using 2D finite difference time domain model incorporating instantaneous Kerr’s nonlinearity. The optimal nonlinear resonant frequencies and the refractive index change required for the performance in the nonlinear regime were obtained. The limiter effectiveness is analysed using extinction ratio. The lattice constant and the optimal microcavity distance required for the proposed model to work as a switch and a limiter in the telecommunication wavelength of 1.55 μm were obtained as a 0.6015μm = and 2a respectively. Introduction Photonic crystals (PCs) are materials with index of refraction varying periodically between high-index regions and low-index regions giving rise to a range of forbidden frequencies called photonic bandgaps analogues to electronic bandgaps in semiconductors [1]. There are three types of PCs depending on one, two or three-dimensional arrangement in periodicity [2]. Although periodic arrangement of atoms within a semiconductor material occurs in nature such as opal gemstones, beetles to bird feathers and butterfly wings, PCs are mostly artificially fabricated. For frequency energies lying within the bandgap, the photonic crystals do not allow light to propagate through unless there is a defect in the otherwise perfect crystal. The introduction of various types of defects, provide the ability to guide and mould the flow of light or photons propagation through the gap. Linear defects can act as efficient waveguides [3] while point like defects may act as resonant micro cavities coupling light to photonic band gap (PBG) waveguides and other optical components [4]. Several studies had been carried out using external modifications of material’s refractive index to change the band-gap structure such as by temperature variations [5] and electro-optic method [6]. However, these are slow in comparison with the speed required for modern communication. The field of nonlinear optics, the propagation of light in nonlinear media having nonlinear relation between dielectric polarization (P) and electric field (E) emerged with the discovery of second-harmonic generation by Franken et al. in 1961 [7]. When nonlinearity is incorporated into a photonic crystal, the light propagation can be controlled dynamically [8]. This field has grown enormously contributing vastly to the advancement of the telecommunication industry and opened up opportunities to design all-optical devices [9]. Kerr nonlinearity is an instantaneous nonlinear response that results a dependence of refractive index on the light intensity. This occurs when intense light propagates in media such as crystals, glass and gases and holds a great importance due to its suitability in ultra-fast devices. Several structures of PC switches have been implemented over the years incorporating Kerr’s nonlinearity [10, 11, 12]. The principle of optical switching and limiting was demonstrated in a one-dimension (1D) by Scalora and Tran in 1993 [10] by modelling both the probe and the pump pulses propagating in the same direction. Using Kerr nonlinearity Scholz et al. designed a two-dimensional optical switch which incorporated the crossed wave guides [11] and due to the perpendicular directions of International Letters of Chemistry, Physics and Astronomy Submitted: 2017-06-29 ISSN: 2299-3843, Vol. 77, pp 1-14 Revised: 2017-09-20 doi:10.18052/www.scipress.com/ILCPA.77.1 Accepted: 2017-10-04 2018 SciPress Ltd, Switzerland Online: 2018-01-25 SciPress applies the CC-BY 4.0 license to works we publish: https://creativecommons.org/licenses/by/4.0/ propagation of the probe beam and the pump pulse, the undesirable overlay of the two signals was reduced. Experiments have been carried out demonstrating all-optical switching action in nonlinear PC cross-waveguide geometry of AlGaAs with Kerr nonlinearity and the transmission of a signal that can be reversibly switch on and off by a control input [13] and thereby accomplishing both spatial and spectral separation between the signal and the control in nonlinear regime. An all optical switch based on nonlinear PC microcavities for AlGaAs was demonstrated numerically based on Finite Difference Time Domain (FDTD) incorporating Kerr effect [14]. Many suggestions have been brought up in implementing optical switches using directional couplers [12, 15, 16] by modifying 2D PC structures by creating two single line defect waveguides adjacent to each other, separated by the single row of rods with decreased radius [12]. In 2008, numerical experiments were carried out investigating the possibility of the radiation intensity stabilization using the 2D PC structures [17] approving the possibility of designing optical power limiter circuits using 2D PCs. Danaie and his colleagues designed a PC optical limiter using nonlinear Kerr Effect for a triangular lattice of holes in a GaAs substrate [18]. Optical limiters have been incorporated in designing nonlinear optical devices such as AND gates using Kerr nonlinearity [19]. To model nonlinearity, finite difference time domain method (FDTD), finite element method (FEM), plane wave expansion (PWE) and Wannier function method (WFM) can be used in incorporating nonlinear elements into the linear system. FDTD method, which enables modelling time evolution of the fields and quantities in the desired structure [20] is regarded as one of the most popular numerical methods used to simulate nonlinearity and dispersion structure. FDTD further enables to model different geometries in different dimensions. FDTD was first proposed by Yee in 1966 [21]. This method proposed a discrete solution to Maxwell’s Equations based on central difference approximations of the spatial and temporal derivatives of the curl operations. It has been developed to a fast algorithm to solve sophisticated problems. An underlying weakness of this method is that it requires a full discretization of the electric and the magnetic fields in the entire volume domain [22]. This work investigates nonlinear optical properties of PCs in optical switching and limiting. 2D PCs with 15×15 square lattice of AlAs rods with air wafer dimensions 17μm 16μm × and lattice constant of a 1μm = and 15×15 hexagonal lattice structures of AlAs rods with the air wafer dimensions17μm 14μm × and lattice constants a 0.866μm = and b 1μm = were considered without loss of generality. Kerr nonlinearity was incorporated and a simulation was carried out based on FDTD method. An optical switch and an optical limiter are proposed using a side-coupled cavity waveguide for AlAs along with fine tuning to work under the telecommunication wavelength. Effects of Nonlinearity Optical nonlinearity is a phenomenon which occurs due to modification of optical properties of a material by the presence of light. Ideally, only laser light in this regard has a sufficient intensity to modify optical properties of material [23]. The propagation of light in a photonic crystal is governed by the macroscopic Maxwell equations: ; ; 0; t t ρ ∂ ∂ ∇× = − ∇× = + ∇⋅ = ∇ ⋅ = ∂ ∂ B D E H J B E , (1) where ρ and J are free electron charge density and current density respectively. The relationships between the four electromagnetic field vectors , , , E D B H are given by: 0 0 ; ( ) ε μ = = D E + P B H + M , (2) where P is the polarization field and M is the magnetization field. Inside a dielectric, the induced polarization P of the medium is given by [23]: (1) (2) 2 (3) 3 o o o P E E E ε χ ε χ ε χ = + + +L (3) 2 ILCPA Volume 77

Modification of Surface Properties of Silicon Wafers by Laser-Assisted Electrochemical Etching

Abstract: In this paper, the structural properties of porous silicon layer PSL were reported. Photo-assisted (laser) electrochemical etching PECE technique used to fabrication PSL from n-type wafer silicon as a function of etching time. Optical microscopy OM image is confirmed that the surface topography of porous silicon layer formation was a mud-like structure. The porosity and thickness have been determined gravimetrically are varied from 61% to 82% and 7.2 µm to 9.4µm respectively. The XRD patterns show that one diffraction peak for all PSL through anodization duration and it is assigned to the (400) plane and data confirmed the porous silicon PS was nanocrystalline.

The Dimerization Effects of Some Solutes on the Partition Coefficient k D in Binary Immiscible Solvents

Abstract: The dimerization of a solute dissolved in binary immiscible solvents shows that the value of the partition coefficient, kD of the solutes are influenced by the dimerization constant, K of the solute in one of the solvents according to the description: (C_X^A)/(C_X^B ) = kD + 2kD2KCxB where CxA and CxB are the concentrations of the solute x in the solvents A and B respectively. Both kD and K are parameters that predict the extent of beneficiation for most minerals. Also, kD is a fundamental parameter that determines the extent of solute recovery during solvent extraction. In this study, it is found that the order K kD and K kD are the effects for acetic and succinic acids respectively in the binary solvents composed of carbon tetrachloride/water and diethylether/water systems respectively. These results suggest that the distributions of these solutes in the solvents are accompanied by the formation of succinic anhydride which is more favoured than the dimerization of the acetic acid. Also, the changes in the values of distribution enthalpies, HD are corroborated to explain these experimental observations.

Hybrid Approach for Synthesis and Antimicrobial Activity of Heterocyclic Compounds

Abstract: We have synthesized novel series of N-(1-(2-(1-phenyl-3-(p-tolyl)-1H-pyrazol-4-yl)-5(pyridin-4-yl)-1,3,4-oxadiazol-3(2H)-yl)ethylidene)arylaniline and their derivatives. The structures of synthesized compounds were well characterized by spectroscopic techniques. Antimicrobial activity of the newly synthesized derivatives was evaluated against gram positive (S. aureus and S. pyogenes), gram negative bacteria (E. coli and P. aeruginosa), and strains of fungi (C. albicans, A. niger and A. clavatus). Among the screened derivatives 5c, 5f, 5i, 5l and 5t demonstrated superior antimicrobial activity against microbial strains.

Synthesis, Characterization and Biological Evaluation of 3'-Benzoyl-5'-(Furan-2-yl)-4'-Phenylspiro[Indoline-3,2'-Pyrrolidin]-2-One Derivatives and its Molecular Docking Studies

Abstract: A series of new spirooxindole derivatives were synthesized via 1,3–dipolar cycloaddition. All the synthesized compounds were evaluated for antimicrobial activity. In antibacterial studies compound 4d demonstrated the most potent inhibitory activity (MIC = 12.5 lg/mL for K.pneumonia, B.cereus and S.typhi), which was compared with the positive control streptomycin. In antifungal studies compound 4e demonstrated the most potent inhibitory activity (MIC = 3.125 lg/mL for C.albicans and A.niger), which was related with the standard drug ketaconazole. In addition, molecular modeling studies were also performed to disclose the binding modes of the most active inhibitors to the amino acid residues that compose the active site of the glucosamine-6-phosphate synthase and crystal structure of human lanosterol 14-alpha dimethylase in complex with ketaconazole enzyme.

Calibration of Therapy Level Ionization Chamber at 60 Co Teletherapy Beam Used for Radiation Therapy

Abstract: The accuracy and traceability of absorbed dose to water measurement of radiotherapy beam is a critical issue to achieve the curative outcome of cancer patients. The current dosimetry protocols for radiotherapy beams TRS-398, TG-51 and DIN-6800-2 are based on the calibration factor of ionization chamber in terms of absorbed dose to water for 60Co beam. The accuracy of the calibration factor of ionization chamber as well as output of radiotherapy beam is the primary requirements of precisional dose deliver to the tumor which is the QA part of radiotherapy dosimetry. In the present study, we have calibrated 9 different ionization chambers (8 thimbles and 1 parallel plate) of various active volumes for 60Co beam against reference standard NE2571 and compared with manufacturer’s values. The Percentage Depth Dose (PDD) and Output Factors (OF) of two cobalt units were measured with standard calibration system by following IAEA dosimetry protocol TRS-398 and compare with 6 MV photon beam from medical linear accelerator. The traceability of the dosimetry was verified by the participation of postal dose IAEA/WHO intercomparison program. The aim of the participation was to investigate uncertainties involved in the calibration of Ionization Chamber (IC) and absorbed dose measurement. The percentage of deviation relative to IAEA mean dose was found to be -0.2% (traceable limit ±5%), which shows an excellent agreement of calibration of beam as well as ionization chamber with international standard. The deviation of factors of ionization chambers between the measured and manufacturer’s values were found within 0.07-2.81% with an uncertainty of ±1.5% (k=1).

Adsorption, Equilibrium and Kinetic Studies of the Removal of Methyl Violet from Aqueous Solution Using White Potato Peel Powder

Abstract: The adsorption of methyl violet (MV) dye onto white potato Peel powder from aqueous solution was investigated by analyzing the operational parameters such as contact time, adsorbent dosage, initial dye concentration, PH and temperature to observe their effects in the dye adsorption process. The optimum conditions for the adsorption of MV onto the adsorbent (WPPP) was found to be contact time (120 mins), PH (10.0) and temperature (303K) for an initial MV dye concentration of 50mg/l and adsorbent dose of 1.0g. The experimental equilibrium adsorption data of the (MV) dye fitted best and well to the freundlich isotherm model. The maximum adsorption capacity was found to be 17.13mg/g for the adsorption of MV. The kinetic data conforms to the pseudo – second order kinetic model.

Synthesis, Characterization and Antimicrobial Activity of 2-[1-(2,4-Dihydroxyphenyl)Ethylene]Hydrazine Carboxamide and its Zn(II) Metal Complex

Abstract: The synthesis of 2-[1-(2,4- dihydroxyphenyl)ethylene]hydrazinecarboxamide and its Zn(II) metal complex was achieved. 2, 4 dihydroxy acetophenone is synthesized by resorcinol with glacial acetic acid. This further treated with semicarbazide hydrochloride to form its semicarbazone. Zn(II) metal complex was prepared by dissolving equimolar quantities of metal salt and Schiff base ligand in ethanol. All the target compounds were characterized by M.P, TLC and UV-visible and IR spectral data. Antimicrobial activities of these synthesized compounds were studied in sterile saline by Agar well diffusion method against M. luteus, B. subtilis, S. aureus, E. coli, P. aeruginosa bacteria. All the synthesized compounds have shown good to moderate antimicrobial activity.

Investigation on Pyrolysis of Shivee-Ovoo Coal from Mongolia

Abstract: Our present investigation on Shivee-Ovoo coal focused on characterization of the initial coal and it’s hard and liquid products after pyrolysis. First of all on the basis of proximate and ultimate analysis of Shivee-Ovoo coal have been confirmed that the Shivee-Ovoo coal is oxidized brown coal of lignite type with B2 mark. The thermal degradation process of Shivee-Ovoo coal was investigated by thermogravimetric analyzer and first time determined the thermal stability of the coal sample by determination of thermal indices such as T5% -71,85°C; T15% -321,18°C; T25% -490,64°C from the TG curve, which are the characteristics of lower thermal stability. The pyrolysis of Shivee-Ovoo coal carried out at different heating temperatures and determined the yields of obtained hard, liquid and gas products. A most suitable heating temperature was chosen 500°C, in which the yield of condensed liquid product-6,28% (tar) was higher. The yield of all liquid (tar and pyrolysis water) and gas products (44%) shows that there was an intensive thermal decomposition of the coal organic mass with higher degree of conversion. This results also confirm the above mentioned and determined lower thermal stability characteristics of Shivee-Ovoo coal and it is more suitable for gasification and liquefaction. Also the yield of hard product (semicoke) is 56,48% at 500°C, which is also important product of the pyrolysis of Shivee-Ovoo coal and it’s proximate analysis results show that the volatile matter content decreased 3 times and increased caloric value by 1000 kcal in comparison with the initial coal sample indicating that it can be used as a smokeless fuel. The determined chemical composition of pyrolysis tar in group organic compounds by chemical analysis show that the tar consists mostly neutral oils with highest content-81,9%, asphalteines-13,6%, free carbons-3,93% and organic bases, organic acids, phenolic compounds are less than 1,0%. The tar also was distilled at room temperature and obtained several fractions with different boiling temperature ranges including yellow colored light fraction-15,93% (18-1800С ), brown colored middle fraction-15,44% (180-3300С ) and black colored heavy fraction-44,53% (330 >0С ). The images of scanning electron microscopes (SEM) of prepared activated carbon from pyrolyzed hard residue in comparison with initial coal sample are different. The SEM image of initial coal sample has compact solid pieces. The SEM image of carbonized and activated coal sample shows a porosity structure with meso and macro pores in comparison with that of initial coal sample. The solubility and chemical composition of neutral oil isolated from the pyrolysis tar of Shivee-Ovoo coal investigated by GC/MS analysis and registered totally 68 peaks (signals) for the soluble in hexane , 100 peaks for the soluble in toluene and 100 peaks for the soluble in a mixed solvent of methylenchloride and methanol (1:1 volume ratio) fractions. Have been determined and identified 22 organic compounds soluble in hexane, 45 organic compounds soluble in toluene and 21 organic compounds soluble in a mixed solvent of methylenchloride and methanol fractions from each related totally registered peaks.