VOLUME 42, NO1, FEB-2020

Beneficiation Study on Low-Grade Graphite Ore of Shounter Valley, Azad Kashmir, Pakistan

A low-grade graphite ore originating from Kael area, Shounter Valley, Azad Kashmir, assaying 8.90% graphite content was upgraded by froth flotation technique to produce a commercial grade graphite concentrate. Mineral phases present in the ore were identified by using X-ray diffraction (XRD) technique. The variables of flotation process such as particle size of the feed, pH of the pulp, % solids of the pulp, speed of impeller, type and quantity of collecting and frothing agents, conditioning time and froth collecting time were optimized to get maximum grade and recovery of graphite mineral. The pH of the pulp was adjusted with sodium carbonate. Kerosene oil was used as collector while pine oil as frother respectively. Sodium silicate was employed as depressant. The grade of the final graphite concentrate produced was 85.80% C with overall recovery of 86.00%. Its surface morphology was studied using SEM-EDX technique while grain size by laser particle size analyzer.read more

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Muhammad Arif Bhatti, Kamran Raza Kazmi, Samreen Zahra, Ansar Mehmood and Rashid Mehmood

Fluorescence and Theoretical Calculation of Phenylhydrazone Derivatives and Fluorine Boron Complex: Synthesis and Fluorescence Characteristics

A sereis of phenylhydrazone-based derivatives and their corresponding BF2 complexes were synthesized efficiently by a three-step reaction. Photophysical performance was investigated in different organic solvents and in the solid state. Although these compounds exhibited feeble fluorescent intensity in solution-state, BF2 complexes showed weaker fluorescence in solid state compared to precursors 2, which were caused by slight geometry relaxation of upon photo excitation. Density Functional Theory calculations was carried out to confirm above inference.read more

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Ping Tang, Luping Lyu and Yujin Li

Spectrophotometric Estimation of Iron (III) in Iron Polysaccharide Complex Capsule Formulation and its Accelerated Stability

Iron plays a pivotal role in human physiology, while its deficiency may prove fatal in severe cases. Analytical methods for the quantitative determination of iron are thus very important. Herein, we report the estimation of iron in iron Polysaccharide complex (IPSC) using raw material and formulations, through a spectrophotometric analytical method. IPSC capsules were formulated and their stability was studied by developing a simple and validated analytical method. The process is based on the acid hydrolysis of IPSC and the development of chromogen by reacting ammonium thiocyanate with IPSC, maximum absorption at 474 nm was observed. Beer's Lambert law (linearity response) was found in the range of 10-20 μg/ml with excellent correlation coefficient of determination (R = 0.998). The quantification and detection limits were established to be 0.45 mcg/ml and 0.14 mcg/ml correspondingly. The recovery of IPSC analysis was 99.25 to 102.28 %. Percentage assay of IPSC capsules showed results around 102.34 %. The formulated IPSC capsule was stable under accelerated conditions for 6 months (% assay > 91.69). The dissolution profile over 60 minutes showed a better dissolution (94%) compared with the internationally marketed IPSC capsule (92%).read more

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Salman Zafar, Farrukh Sier, Samiullah, Gohar Ayub and Rahat Ullah

Optimization of Cr Seed Layer Effect for Surface Roughness of As-Deposited Silver Film using Electron Beam Deposition Method

The surface roughness is an important parameter in determining the physical properties and quality of thin films deposited by physical vapor deposition (PVD) method. The presence of an intermediate layer between metallic nanoparticles and substrate significantly promotes the adhesion and reduces the surface roughness. In this article, we have investigated the effect of Chromium (Cr) seed layer to optimize the surface roughness on the growth of as-deposited silver (Ag) film using borosilicate glass and silicon wafer substrates. For this purpose, Ag thin films were deposited with a Cr seed layer of different thickness on borosilicate glass and silicon wafer substrates using an electron beam (E-Beam) deposition method. The Cr thin film of different thickness ranging from 1 nm to 6 nm was thermally evaporated and pure Ag with the same thickness was evaporated at the same rate on previously coated substrates. The deposition of the nanostructured thin film was confirmed by UV-Vis and XRD characterizations. The difference in transmittance for uncoated and coated substrates ensured the deposition. The presence of pure Ag crystalline phase was confirmed by XRD pattern. Surface roughness was measured using Atomic Force Microscopy (AFM) and the conductance was measured using 4-probe conductivity method. The density of nanoparticles and smoothness were visualized from two dimensional (2D) and three dimensional (3D) surface height histograms of representative AFM images. The quantitative roughness was measured in terms of root mean square (RMS) roughness and mean roughness. The high dense and smoother thin films were found for ~2-4 nm Cr layer thickness in case of the glass substrate. The slight increase in roughness was observed for ~1-6 nm Cr layer thickness in case of the silicon substrate. The dependence of the conductivity of thin films on surface roughness is investigated to verify the effect of surface roughness on different applications of Ag thin film. The conductance results have been analyzed as; for a glass substrate, conductivity was maximum for thin films containing ~2 nm Cr seed layer thickness, while for silicon substrate the maximum conductivity was found for the thin film containing ~1 nm Cr seed layer.read more

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Naseem Abbas, Muzamil Hussain, Nida Zahra, Hassaan Ahmad, Syed Muhammad Zain Mehdi, Uzair Sajjad and Mohammed Amer

Determination of Bendiocarb Insecticide by Reverse Flow Injection Analysis Using a Solid-Phase Reactor Containing Micro PbO2, Nano PbO2 and Grafted SiO2 - PbO2 Immobilized

Bendiocarb (BEN) is an acutely toxic carbamate insecticide which used in public places and agriculture, it is also effective against a wide range of nuisance and disease vector insects. A new rapid and sensitive reverse flow injection spectrophotometric procedure coupled with on-line solid-phase reactor is designed in this article for the determination of BEN in its insecticidal formulations and water samples, by using three different solid-phase reactors containing bulk PbO2 (B-SPR), PbO2 nanoparticles (N-SPR) and grafted nanoparticles of SiO2-PbO2 (G-SPR) immobilized on cellulose acetate matrix (CA). This method of oxidative coupling is based on alkaline hydrolysis of the BEN pesticide, and then coupled with N,N dimethyl-p-phenylenediamine sulphate (DMPD) to give a blue color product which measured at λmax 675 nm. It worth to mentioned that under optimal conditions, Beer’s law is obeyed in the range of 1-175 μg mL-1 for B-SPR and 0.25-70 μg mL-1 of BEN for both N-SPR and G-SPR respectively within limit of detection (LOD) of 0.931, 0.234 and 0.210 μg mL-1 for B-SPR N-SPR and G-SPR respectively. The surface methodology of the solid phase was also investigated by using atomic force microscopy.read more

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Malik H. Alaloosh Alamri, Sadeem Subhi Abed and Abdulkareem M. A. Alsammarraie

Optimization and Modeling of Photooxidative Process for the Degradation of Reactive Red223

The optimization of the photooxidative process was carried out with the application of Response Surface Methodology (RSM) to degrade Reactive Red 223 (RR223) dye. Operational parameters of U.V/H2O2 process such as irradiation time, initial [dye], initial [H2O2] and distance between U.V lamp and the solution were optimized with Central Composite Design (CCD). Correlation coefficient value of the CCD was obtained to be 79 %, showing the correctness of the model and the successful utilization of CCD in getting desired levels of the factors of the process. Moreover, the optimum points were located with the graphical surface and contour plots. At the optimal conditions, the photooxidative removal of the color and COD were observed to be 68%, 81%, respectively. Furthermore, the pseudo-second order kinetic was guiding the removal of the dye in the process. Subsequently, the electrical energy consumption was estimated in term of the merit electrical energy per order (EEO). The figure of merit of the process was found to be 252 kWhm−3 order−1. The cost of the treatment was also calculated to be US$ 25/m3.read more

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Abdul Rauf Shah, Hajira Tahir and Tahira Yasmeen

Determination of Thermodynamic Parameters from the Dissolution of Strontium Hydroxide in Water and Mixed Solvent Systems by pH-Metric Method

In this study, saturated solutions of Sr(OH)2 in pure water and in mixed solvent systems (methanol - water, ethanol - water, 1-propanol - water, and 2-propanol - water) at two temperatures were prepared and titrated with standard HCl solution by using pH metry. Using these titration data, the molar solubility (s), solubilty product (Ksp) and Gibbs free energy (Go), entropy change (ΔS°) and enthalpy change (ΔH°) for dissolution of strontium hydroxide was determined. At room temperature (20°C), the s, Ksp, ∆Go were found to be 4.28 x 10-2 mol L-1, 3.13 x 10-4 mol3L-3 and 19.70 kJ mol-1 respectively. The ΔH° and ΔS° of the reaction is 2.90 kJ mol-1 and – 60.80 J. mol-1 K-1. With increasing percentage content of organic solvent in mixed solvents, the molar solubility and Ksp decreased and ∆Go, ΔH° and ΔS° values increased. The results were correlated with the dielectric constant value of the solvents used in the study.read more

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Shamsher Ali, Shabir Hussain, Irfan Ali and Syed Azhar Ali

Simulation and Analysis of Propylene Coordination Polymerization Process Based on Aspen (polymer) plus

Based on the industrial conditions of coordination polymerization of polypropylene, Polymer plus was used to simulate and analyze the coordination process of propylene. The effects of the amount of propane, main catalyst (TiCl4), chain transfer agent (hydrogen), shielding gas (nitrogen), and monomer (propylene) on the number average degree of polymerization (DPN), the weight average degree of polymerization (DPW), the number average molecular weight (MWN), the weight average molecular weight (MWW), the polydispersity index (PDI), and the throughput of polypropylene were explored to guide actual production in this paper. Through analysis, the polymerization degree and molecular weight of polypropylene could be adjusted by hydrogen in actual production. The monomer (propylene) should be purified as much as possible to reduce the feed amount of propane. The increase of the propylene contributed to the molecular weight and polymerization degree of the product. The increase in the nitrogen feed amount had no effect on the product performance index. The feed amount of nitrogen could be adjusted as needed according to the actual equipment specifications. The catalyst has the greatest influence on the comprehensive performance index of the product, thus the amount of main catalyst TiCl4 must be strictly controlled.read more

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Jinjin Wang, Wangbin Chen, Manlin Zhang, Bin Pan, Xiaorong Wang, Bin Wang

Investigation of Creep Behavior of CNT Reinforced Ti6Al4V Under Dynamic Loads

This study investigates the effects of addition of Carbon nanotube (CNT) at different volume ratios (0.5- 5%) into Ti6Al4V matrix by mechanical alloying in terms of the density, microstructure, hardness and creep under dynamic load. As a result of the good bonding of carbon nanotubes powders with the main matrix, Ti-6Al-4V/CNT composites have experienced change both in microstructure and mechanical properties (such as hardness, density) and, correspondingly, qualitatively creep behaviour of Ti-6Al - 4V matrix alloy has been improved compared to the lean one. The density of CNT reinforced Ti6Al4V composites sintered at 1300°C for 3h decreases with increasing CNT content. The hardness tests indicated that the hardness of composites increased with CNT addition. In addition, although creep strain is decreased continually with CNT content until 5%, creep life increased with increasing CNT content until 4% of CNT but decreased above 4%. After sintering at 1300 °C under vacuum for 3 hours the density of the composite material reached to a level of 98.5 %, the microhardness to 538 HV and the creep behaviour was improved. The characterization of Ti6Al4V / CNT composites after mechanical alloying was carried out using scanning electron microscopy (SEM), energy dispersive x-rays spectroscopy (EDS) analysis and X-ray diffraction (XRD) methods. Although Ti–6Al–4V alloys are used as biomaterial, this study aimed at using MWCNTs containing Ti-6Al-4V composites at high temperature applications. Because MWCNTs reinforced Ti-6Al-4V composites are cheaper and have lower weight than the other materials used in this kind of applications.read more

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Ismail Topcu, Burcu Nilgün Çetiner, Arif N. Güllüoğlu and Özkan Gülsoy

Synthesis of 2,5-diphenyl-3,4-distyrylcyclopenta-2,4-dienone

A series of 2,5-diphenyl-3,4-distyrylcyclopenta-2,4-dienone (3a-i) and 2,5-diphenyl-3,4-bis((1E,3E)-4-phenylbuta-1,3-dienyl)cyclopenta-2,4-dienone (5) have been synthesized by the condensation of various (1E,5E)-1,[-diarylhexa-1,5-diene-3,4-dione (1a-i) and (1E,3E,7E,9E)-1,10-diphenyldeca-1,3,7,9-tetraene-5,6-dione (4) with 1,3-diphenylpropan-2-one (2) using sodium hydride in dichloromethane. Electronic absorption and emission spectral studies have shown an efficient π-interaction due to the extended conjugation in the cyclopentadienones (3a-i, 5). The electronic excitation in the near UV-region (250-390 nm) to strong emission near (500-690 nm), allowing these to consider as light-harvesting species.read more

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Syeda Shaista Gillani, Munawar Ali Munawar, Khalid Mohammed Khan and Ch. Jamil Anwar