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Print ISSN: 1675-3402
Online ISSN: 2180-4230


FORTHCOMING ISSUE

  • Antibacterial Activity of Copper-doped Montmorillonite Nanocomposites
    Prepared by Alkaline Ion Exchange Method

    Hamideh Pourabolghasem, Mohammad Ghorbanpour and Razieh Shayegh

    Abstract:
  • The antibacterial activity of copper-doped montmorillonite nanocomposites (Cu-MMT) has been investigated. Copper loaded clay nanocomposites have been synthesised by alkaline ion exchange processes in media containing copper sulfate at 550°C. Characterisation studies on the composites were done by X-ray diffractometry (XRD), SEM and absorption spectra analysis. SEM results indicated the diffusion of copper to the inner montmorillonite layer and opening of presenting cracks on its surface. The XRD analysis showed the presence of copper oxide (CuO) structure intercalated within the clay mineral layers. The antimicrobial effects of doped montmorillonite powders against pathogen bacterial strains Escherichia coli and Staphylococcus aureus were tested in broth media. Quantitative test in liquid media clearly showed that copper-doped samples had viable cells reduction ability for testing strains. The excellent antimicrobial activity of the composites was observed on S. aureus. In addition, the composite showed good stability in water and good promise for use in water treatment..

  • An Evaluation of Sodium Ethyl Xanthate for the Froth Flotation Upgrading of
    a Carbonatitic Copper Ore
    Abraham Adewale Adeleke, Meso Florence Mokgethwa and Peter Mandonidis

    Abstract:
  • The carbonatitic Palabora copper ore was ground to the less energy intensive coarse size consisting of 45% passing 75 µm in a ball mill for 20 min and froth floated in a 4.5 l Denver cell at varying dosages of the highly selective sodium ethyl xanthate (SETX) at 200, 250, 300, 350 and 400 g/t. The concentrates were collected every 15 s at varying scraping times of 3, 7 and 10 min. The results obtained showed that that the highest recovery of 86.1% was obtained at the 300 g/t SETX dosage with the lowest grade of 11.29%, while the highest grade of 13.95% occurred at the lowest recovery of 78%. The dosages of SETX used for the flotation was found to be generally higher than that of sodium iso-propyl xanthate (SIPX) used for another copper ore of non-carbonatitic origin. However, the successful flotation of the ore ground coarser than the conventional practice of 80% passing 75 µm is economically significant in view of the potential power conservation obtainable.


  • Properties of Recycled High Density Polyethylene (RHDPE)/Ethylene Vinyl
    Acetate (EVA) Blends: The Effect of Blends Composition and Compatibilisers
    A. R. H. Fatimah, Supri Abdul Ghani and Z. Firuz

    Abstract:
  • Recycled high density polyethylene (RHDPE)/ethylene vinyl acetate (EVA) blends with different blend compositions and compatibilisers were prepared by using melt blending technique in Brabender Plasticorder at temperature 160°C and rotor speed of 50 rpm for 10 min. The compatibilisation of RHDPE/EVA blends were enhanced by the addition of 6 phr of polyethylene- grafted-maleic anhydride (PE-g-MAH) and caprolactam-maleic anhydride (CL-MAH) as compatibilisers. The tensile properties, swelling behaviour, morphology and infrared spectroscopy analysis were studied. The tensile properties and morphology analysis showed that RHDPE/EVA blends became softer with the increasing EVA content. The results also revealed that there was good compatibility between RHDPE/EVA blends with addition of PE-g-MAH and CL-MAH lead to improvement in tensile properties and swelling behaviour of the blends compared to RHDPE/EVA blends without the presence of compatibilisers. SEM morphology displayed better interfacial adhesion due to good dispersion and interaction between RHDPE and EVA phases into each other caused by the compatibilisation effect of PE-g-MAH and CL-MAH. Fourier transformed infrared spectroscopy (FTIR) revealed the structure of the polymer blend with the addition of CL-MAH and PE-g-MAH as compatibilisers.


  • Enhanced Band Gap Energy and Electrochromic Behaviour of Selenium
    Incorporated Copper Thin Film
    J. Peter, P. Karpagavinayagam and C. Vedhi

    Abstract:
  • Selenium incorporated copper (CuSe) thin films are deposited on indium tin oxide (ITO) substrate by cyclic voltammogram of 5.0 ml of 0.1 M CuSO4 and 2 ml of 0.05 M selenium dioxide at potential range from –0.8 V to 0.7 V vs. Ag/AgCl in pH 1.0. The adherent nature, electroactivity and stability of the CuSe thin film were found to be good. The transmittance and absorption of thin films was analysed through UV-Vis spectra. An energy gap of 1.78 eV is obtained for CuSe thin films by extrapolating the linear portion of the curves h? versus (ah?)2. X-ray diffraction patterns revealed that the deposited films possess cubic structure with lattice constant (a) value 80.892Å. Surface morphology of thin film shows uniform granular mixed texture-like structure. The sizes of the grains are found to be in the range between 53.33 nm and 93.33 nm. The film composition was investigated using an EDX micro analytic unit attached with scanning electron microscope. The in- situ spectroelectrochemical behaviour of CuSe thin film at various applied potentials in 0.1 M H2SO4. CuSe thin film exhibits dual colour chromic behaviour from contrast red colour to contrast yellows colour. The electrochromic device shows good optical contrast, coloration efficiency, response time and stability.


  • Measurement of Shielding Effectiveness of Building Blocks against 662 Kev Photons
    Oluwaseun Adedoyin and Abiodun Ayodeji

    Abstract:
  • This study uses building blocks as a shield for gamma energy source of 662 KeV from Cs- 137. The attenuation from the block is compared with those obtained when conventional shields like iron, lead and concrete are used as shield for Cs-137. This was done with the aim of finding out the level of shielding and the thickness of building block needed to confer same level of shielding as the already mentioned conventional shields. Results obtained using a gamma spectrometer with a NaI(Tl) detector showed that the Half Value Thickness (HVT) of Building block, Concrete, Iron and Lead were 5.1420 cm, 3.8043 cm, 1.1908 cm, and 0.5581 cm respectively. With the results from this work, a shield of 37 cm building block (though bulky in size) will attenuate the source and can be used as a substitute for lead which would require a 4.4 cm thickness.

  • Tensile and Thermal Properties of Crosslinked Chitosan/Empty Fruit Bunch
    Biofilms by Phthalic Anhydride
    Salmah Husseinsyah, Chan Ming Yeng and Mohamad Arine Aizeq Ahmad Amirudin

    Abstract:
  • Chitosan (CS) has high potential applications in packaging, agriculture and food. However, the cost of chitosan is higher. Therefore, the addition of agriculture waste such as empty fruit bunch (EFB) in CS was studied in order to reduce the cost of CS. The CS/EFB biocfilms were prepared through solvent casting method. This research paper study the effect of phthalic anhydride (PA) crosslinking agent on tensile, morphological and thermal properties of CS/EFB biofilms. The results indicated that the tensile strength and elongation at break of uncrosslinked CS/EFB biofilms decreases but the modulus of elasticity increases as increasing EFB content. In addition, the glass transition temperature (Tg) of CS/EFB biofilms increased with EFB content. On the other hand, the crosslinked CS/EFB biofilm with PA showed higher tensile properties such as tensile strength, elongation at break and modulus of elasticity in comparison with uncrosslinked biofilms. While, the Tg of crosslinked CS/EFB biofilms higher than uncrosslinked biofilms due to formation of amide linkages. The formation of amide bonds between CS and PA were demonstrated in FTIR result. The better filler dispersion and filler-matrix adhesion were proven by Scanning electron microscopy (SEM). Furthermore, the percentage gel fraction of both uncrosslinked and crosslinked CS/EFB biofilms increased with increasing of EFB content. On the other hand, the crosslinked CS/EFB biofilms exhibited higher gel fraction than uncrosslinked biofilms due to the formation of amide crosslinkages in crosslinked biofilms.


  • The Synthesis and Characterisation of 2-methyl-N-((4-methylpyridine-2-yl)
    carbamothiol) Benzamide: Its Preparation with Antibacterial Study
    Farook Adam, Nur Nadia Fatihah, Nadiah Ameram, Sreeramanan Subramaniam
    and Safiah Ahmad Mubarrakh


    Abstract:
  • The compound, 2-methyl-N-((4-methylpyridin-2-yl)carbamothioyl)benzamide was derived from ortho-toluylchloride and 2-amino-4-picoline. It was fully crystallised and characterised on the basis of elemental analysis, X-ray crystallography and spectroscopic techniques namely infra-red, Uv-Vis and nuclear magnetic resonance. The melting point was in the range of 164.9°C–165.8°C. The Fourier transform infrared (FTIR) analysis shows the following vibrational frequencies for ?(N-H), ?(C=O), ?(C-N) and ?(C=S) at 3237 cm–1, 1683 cm–1, 1329 cm–1 and 1154 cm–1 respectively. 1H NMR results showed chemical shifts at 9.140 ppm and 12.983 ppm for the two N-H protons. Single crystal X-ray diffraction studies on the compound showed it to be a rigid molecule due to the presence of internal hydrogen bonding. The compound shows antibacterial activity towards gram positive and gram negative bacteria.


  • Ultrasound-assisted Extraction of Oil from Calophyllum inophyllum Seeds:
    Statistical Optimisation using Box-Behnken Design
    Faiznur Mohd Fuad and Khairiah Abd. Karim

    Abstract:
  • Ultrasound-assisted extraction (UAE) of oil from Calophyllum inophyllum Linn seeds was studied and the effects of four factors (extraction time, ultrasound power, extraction temperature, liquid to solid (L/S) ratio) on the oil yield were optimized by using a statistical tool. Specifically, the optimisation was carried out by employing a Box-Behnken statistical experimental design. The experimental data were fitted to a quadratic model using multiple regression analysis giving high determination coefficient value (R2) of 0.984. The predicted oil yield was optimum (56.2%) when the extraction were conducted for 21 min, 210 W ultrasound power, 42°C extraction temperature and 21 ml/g L/S ratio. Based on the model summary statistics, the experimental values agreed closely with the predicted values, indicating an excellent fit of the model used. The results indicated that Response Surface Methodology (RSM) was effective for optimising the UAE conditions of oil from C. inophyllum seeds.


  • Corn Cob as a Potential Feedstock for Slow Pyrolysis of Biomass
    Nur Syairah Mohamad Aziz, Adilah Shariff, Nur Ismiza Ismail and
    Nurhayati Abdullah


    Abstract:
  • The aim of this study is to investigate the characteristic of corn cob as a biomass feedstock for slow pyrolysis process. This was achieved by using proximate, elemental and thermogravimetric (TG) analysis as well as heating value, pH and lignocellulosic determination. Proximate analysis was performed using ASTM E1756-01, ASTM E1755-01 and ASTM E872-82. Proximate analysis showed that the corn cob feedstock contained 87.76 mf wt% of volatile matter, 1.05 mf wt% of ash content and 11.09 mf wt% of fixed carbon. The elemental analysis revealed that corn cob feedstock contain less than 1 mf wt% of nitrogen and sulfur. The percentages of cellulose, hemicelluloses and lignin of corn cob feedstock are 45.88%, 39.40% and 11.32% respectively. The weight loss of corn corn cob feedstock was prominent in the temperature range of 250°C–350°C. Two distinct peaks of DTG curve indicate the difficulty of corn cob feedstock to degrade due to its high fixed carbon content. The overall findings showed that corn cob is suitable to be used as the feedstock for slow pyrolysis because of its high volatile matter and low percentages of nitrogen and sulfur. Its high fixed carbon makes it a potential feedstock for the slow pyrolysis of biomass.


  • Heavy Metal Profile of Shilajit Samples Obtained from Gilgit and Chellas,
    Pakistan (Short Communication)
    Muhammad Rahim, Imdadullah Mohammadzai, Waseem Hassan and
    Nazir Ahmad


    Abstract:
  • Shilajit is considered as one of the wonder medicines of Ayurveda. It is an important drug of the ancient Hindu material medica and is to this day used extensively for a variety of diseases. However, there are a number of reports which have associated metal poising with traditional use of herbal medicine including Shilajit. The study was designed in this regard to determine the prevalence and concentration of heavy metals in Shilajit obtained from natural valleys of Gilgit (sample A) and Chellas (sample B) which are commonly used in Pakistan. Determination of heavy metals was carried out using atomic absorption spectrophotometry. Iron, zinc, chromium, manganese, cobalt and lead were detected in both samples with percentage of these metals in sample A were 0.19680%, 0.08705%, 0.01138%, 0.0026%, 0.00051% and 0.00008%, respectively. While sample B contains these metals in the following percentages: 0.03210%, 0.00213%, 0.00154%, 0.00147%, 0.00055% and 0.00023% respectively. Our data indicated that the metal concentration in both tested samples are within permissible level as prescribed by world health organization and are not associated with detrimental health effects.

 

 


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