Blantyre, Malawi


Blantyre, Malawi
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Wellen R.M.R.,Federal University of Pernambuco | Canedo E.L.,Polytechnic | Rabello M.S.,Federal University of Campina Grande
Journal of Applied Polymer Science | Year: 2012

Blends of poly(ethylene terephthalate) (PET) with small amounts of styrene-co-acrylonitrile (SAN) were prepared by melt blending, and cold crystallization of these mixtures was investigated by means of differential scanning calorimetry. The results suggest that SAN interacts with the amorphous phase of PET, as observed by variations in the glass transition temperature and in the morphology of the blends, analyzed by scanning electron microscopy. The addition of 1% SAN promoted a significant reduction in the crystallization rate of PET, in a manner similar to that of an antinucleating agent. However, the crystallinity of the PET/SAN blends was comparable with that of neat PET; hence, mechanical properties were only slightly affected. Kinetic parameters were determined using Avrami theory; Avrami plots presented a nonlinear behavior at the end of crystallization, indicating that cold crystallization proceeds in two stages. © 2012 Wiley Periodicals, Inc.

Chelating ion-exchange resin (pHFR) has been synthesized by condensing p-hydroxybenzoic acid with formaldehyde employing resorcinol as cross linking agent at 80 ± 5 °C using DMF as a solvent. The resin was characterized by elemental analysis, FTIR, 1H-NMR and XRD. The thermal analysis (TGA, DTA and DTG) was done at the heating rate of 10 °C/min in N2 atmosphere. The morphology of the resin was studied by optical photographs and scanning electron micrographs (SEM) at different magnifications. The physico-chemical properties have been studied. The uptake behaviour of various metal ions viz. Ni(II), Cu(II), Zn(II), Cd(II) and Pb(II) towards pHFR resin have been studied depending on contact time, pH, metal ion concentration and temperature. The maximum uptake capacity for Ni(II), Cu(II), Zn(II), Cd(II) and Pb(II) are found 1.310, 2.304, 1.690, 1.591 and 2.020 mmol/g respectively. The selectivity order is: Cu(II)>Pb(II)>Zn(II)>Cd(II)>Ni(II). The intra-particle diffusion rate constant (Kid) and external diffusion rate constant (Ks) are calculated by Saphn-Schlunder and Weber-Morris models respectively. Equilibrium adsorption data were analyzed by Langmuir and Freundlich equations. The adsorption process follows first order kinetics and specific rate constant Kr was obtained by the application of Lagergan equation. Thermodynamic parameters viz. ΔG°, ΔS° and ΔH° have also been calculated for the metal-resin systems.

Oluwafemi F.,Abeokuta Federal University of Agriculture | Odebiyi T.,Abeokuta Federal University of Agriculture | Kolapo A.,Polytechnic
World Mycotoxin Journal | Year: 2012

There are indications that significant levels of mycotoxins may be absorbed from inhaled fungal spores. The problem is likely to be most serious with aflatoxins. Indoor airborne fungi in three feed mills in south-western Nigeria were assayed using Sabouraud dextrose agar and coconut agar medium. Fungi isolated include Aspergillus flavus, Rhizopus spp., Aspergillus fumigatus, Aspergillus candidus, Aspergillus niger and Aspergillus terreus with incidence rates of 61, 15, 12, 5, 5 and 2%, respectively. Amount and type of aflatoxins produced in Sabouraud dextrose broth by aflatoxigenic strains of A. flavus isolated at the three mills were strain dependent. Exposure of feed mill workers to aflatoxins was assessed by HPLC analysis of blood samples. Subjects from different occupational groups served as a control group. The mean concentrations of aflatoxin B1, B2, G1 and G2 in blood samples of the feed mill workers varied from 73.4-189.2, <0.1-0.5, 0.3-1.9 and <0.1-3.4 ng/ml, respectively. There was a significant difiference between the mills regarding blood aflatoxin levels of the workers; poorly ventilated mills resulted in higher blood aflatoxin B1 levels. Aflatoxin B1 was not detected in the blood samples of the control group; mean concentrations of aflatoxin B2, G1 and G2 detected in this group varied from <0.1-0.3, 0.4-1.5 and <0.1-0.3 ng/ml, respectively. Results from the present study showed that ventilation of feed mills is an important issue that should be considered to lower the risk of aflatoxin exposure among feed mill workers. © 2012 Wageningen Academic Publishers.

Shah B.A.,Veer Narmad South Gujarat University | Patel H.D.,Veer Narmad South Gujarat University | Shah A.V.,Polytechnic
Environmental Progress and Sustainable Energy | Year: 2011

This study is envisaged for modification of sugar industry waste bagasse fly ash (BFA) into a beneficial sorbent zeolite (ZFA) having improved morphology for the effective removal of basic dye methylene blue (MB) from aqueous solution. BFA was efficiently transformed to ZFA by alkaline hydrothermal treatment. Both the virgin and treated BFA were characterized using various techniques to obtain its physical and chemical constituents. The major change in the morphology of BFA and ZFA was examined by X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy. Modified adsorbent ZFA showed surface with deeper pore, indicating vanishing crystalline glass phase of BFA. The equilibrium and kinetic studies are carried out with the synthetic solutions of MB. It was found that the solute removal is favored at a lower solute concentration, increased agitation time, increased dose of adsorbent, and higher temperature. The adsorption capacities of BFA and ZFA were found to be 71% and 45%, respectively, for removal of MB at optimized conditions. Langmuir, Freundlich, and Dubinin-Radushkevich isotherm models were adopted to describe the adsorption isotherms. Adsorption isotherms of MB dye could be best modeled by Dubinin-Radushkevich isotherm for ZFA and Langmuir isotherm for BFA. The results clearly showed that the removal capacity of ZFA was seen to be higher than that of BFA. © 2010 American Institute of Chemical Engineers.

Shah B.A.,Veer Narmad South Gujarat University | Surati P.R.,Veer Narmad South Gujarat University | Shah A.V.,Polytechnic
Molecular Crystals and Liquid Crystals | Year: 2013

A new Schiff base compound 4((o-tolylimino)methyl)-3-methyl-1-phenyl-1H- pyrazol-5-ol(4TM-MPP) was synthesized and characterized by elemental analyses, LC-MS, FTIR, and 1H-NMR spectra. The compound exhibits photochromic property under 365 nm UV-light irradiation, which can be observed with solid state reflectance spectra. It suggests that the photoisomerization is due to photoinduced intermolecular hydrogen bond, which results in enol to keto transformation. The chemionics study is carried out using (Ni+2, H+), (Ag+, H+), and (Na+, H +, and OH-) using the UV absorption spectra in solution, which shows logic behavior of INHIBIT, NOR, and XOR, respectively. © 2013 Copyright Taylor and Francis Group, LLC.

Thole B.,Polytechnic
Journal of Water Sanitation and Hygiene for Development | Year: 2014

One of the parameters that impact on fluoride sorption capacities of materials in water defluoridation is initial concentration. Water from various sources will have different fluoride concentrations; as such the employment of a particular media in defluoridation requires information on how the media will perform in different concentrations. Consequently, research was carried out to determine how initial fluoride concentrations in raw water affect capacity in defluoridation with bauxite, gypsum, magnesite and their composite, and to investigate the possibility of predicting loading capacity of their compositefilter through initial fluoride concentration to optimize their application in defluoridation. The results showed that sorption capacities increased with increase in initial concentrations. However, higher starting concentrations resulted in larger residualfluoride concentrations; as such the benefit of large sorption capacities obtained was overshadowed. Polynomial relations of capacity (Cs, mg/g) and initial concentration (Co, mg/l), were obtained for bauxite and gypsum. Magnesite obtained a logarithmic relation for Cs and Co. A power relation was obtained between Cs and Co for their composite, Cs = 0:0328C 1:2016 o. Approximation of capacities of this composite from initialfluoride concentrations was feasible. Water defluoridation has become important as a result of dental and skeletal fluorosis.

Mladenovic M.,Virginia Polytechnic Institute and State University | Abbas M.,Polytechnic
Traffic Engineering and Control | Year: 2012

Transportation agencies across the world are facing the need for improvement in the management of transportation networks under their control. One of the challenges is safe and effective control of largescale traffic light systems. As one of the solutions to these requirements, agencies are sometimes installing Adaptive Traffic Control Systems. This paper, which follows on from page 26 of TEC January 2012 is focusing on potential functional requirements for selection, thus establishing the groundwork for their procurement and installation.

Shah B.A.,Veer Narmad South Gujarat University | Shah A.V.,Polytechnic | Mistry C.B.,Veer Narmad South Gujarat University | Navik A.J.,Veer Narmad South Gujarat University
Environmental Earth Sciences | Year: 2013

Heavy metal accumulation due to industrial activities has become a very sensitive issue for the survival of the aquatic life. Therefore, distributions of several heavy metals have been studied in the surface sediments of Tapti-Hazira estuary, Surat, to assess the impact of anthropogenic and industrial activities near estuary. Totally 60 sediment samples were collected from four different sites at Tapti-Hazira estuary, Surat from January 2011 to May 2011 and examined for metal contents. The average heavy metal load in the study area are found to be 43.28-77.74 mg/kg for Pb, 48.26-72.40 mg/kg for Cr, 117.47-178.80 mg/kg for Zn, 71.13-107.82 mg/kg for Ni, 123.17-170.52 mg/kg for Cu, 0.74-1.25 mg/kg for Cd, 14.73-21.69 mg/kg for Co. Calculated enrichment factors (EF) reveal that enrichment of Pb and Cd is moderate at all sites, whereas other metals Cr, Ni, Zn, Co, and Cu show significant to very high enrichment. Geo-accumulation index (I geo) results revealed that the study area is nil to moderately contaminated with respect to Cd, moderately to highly polluted with respect to Pb, Zn, and Cu and high to very highly polluted with respect to Co and Cr. © 2012 Springer-Verlag Berlin Heidelberg.

Shah B.A.,Veer Narmad South Gujarat University | Shah A.V.,Polytechnic | Shah P.M.,Veer Narmad South Gujarat University
Iranian Journal of Chemistry and Chemical Engineering | Year: 2010

Salicylic acid-Formaldehyde-m-Cresol (SFM) terpolymer had been synthesized in DMF media by conventional method. The resulting resin had been characterized by FTIR spectra, elemental and thermogravimetric analyses. The morphology of SFM resin had been studied by SEM and Optical photograph. Various parameters like rate of equilibration, effect of pH on ion exchange capacity and effect of concentration on ion exchange capacity had been studied. The maximum sorption capacities at 0.05M concentration for Ni(II) and Cu(II) were 0.7905 (pH-6.0) and 0.6315 (pH-5.5) mmol/g of dry resin respectively. The distribution coefficient (Kd ) for five metal ions [Ni(II), Cu(II), Zn(II), Cd(II) and Pb(II) ] were determined in various concentration of tartaric acid electrolyte at different pH. The quantitative separations of heavy metal ions and transition metal ions from their admixtures [Cu(II)- Pb(II), Pb(II)- Zn(II), Ni(II)- Cd(II)] had been performed by using distribution coefficient (Kd).

Shah B.,Veer Narmad South Gujarat University | Tailor R.,Veer Narmad South Gujarat University | Shah A.,Polytechnic
Journal of Dispersion Science and Technology | Year: 2012

Zeolitic material (ZBFA) was synthesized from the bagasse fly ash (BFA) by alkaline hydrothermal treatment for effective removal of phenol from aqueous solutions. The BFA and ZBFA were characterized by XRF, FTIR, PXRD, and SEM. Zeolite-P was found dominant constituent of the synthesized zeolitic materials. Batch sorption experiments were carried out to investigate the sorption capacity of synthesized material at various operational parameters. Sorption of phenol on BFA and ZBFA proceeds by pseudo-first order kinetic model. The overall sorption process was governed by intraparticle and external diffusion mechanisms. The practical applicability of the zeolitic material has been investigated in the column operation mode. The value of breakthrough capacity (38.68 mg/g) was more than batch capacity (35.42 mg/g). © 2012 Copyright Taylor and Francis Group, LLC.

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