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  1. Syakirah Shahrudin, Azizah Hanom Ahmad
    Science Letter, 2016;10(2):26-30.
    MyJurnal
    In this work, polymer electrolytes have been prepared by doping starch with Sodium Phosphate (Na3PO4). The incorporation of 25% Na3PO4 optimizes the room temperature conductivity of the electrolyte at 7.27 x 10-6 Scm-1. The temperature dependence of conductivity for the electrolyte is Arrhenius and the activation energy, Ea, of 75% corn starch-25% Na3PO4 electrolyte is 0.26eV. The dielectric studies reveal the non-Debye nature of the electrolyte. The complexation of Na3PO4 with the polymer host was studied using Fourier transform infrared (FTIR) spectroscopy.
  2. Hazwani Hasmi, Asmida Ahmad, Faeiza Buyong
    Science Letter, 2016;10(2):19-22.
    MyJurnal
    —Anaerobic digestion (AD) of biomass is a well-established process to produce renewable energy, where organic matter is converted to biogas by microorganism. High solid content and complex structure of sludge-derived organic matter, methane production during digestion is limited at the hydrolysis step. Therefore pre-treatment of substrate is a way to accelerate the hydrolysis step. This study aimed to identify the optimum pre-treatment method to increase the methane production from poultry waste prior anaerobic digestion. The poultry waste was mixed with water, pre-treated, seeded with inoculums. Chemical and thermochemical pre-treatment were performed with NaOH and Ca(OH)2. The AD was conducted in bioreactors and incubated in water bath at 37 °C for 15 days. Results obtained show that the highest methane yield was at the thermochemical pre-treatment with Ca(OH)2 with cumulative amount of methane at 1665.17 ppm followed by chemical pre-treatment with Ca(OH)2, thermochemical pre-treatment with NaOH and chemical pre-treatment with NaOH with cumulative amount of methane at 1381.76 ppm, 884.07 ppm and 607.98 ppm respectively. Based on the comparison of the results, the thermochemical pre-treatment with Ca(OH)2 is the best pre-treatment as it produced the highest methane yield.
  3. Hedzlin Zainuddin, Maisarah Ismail, Nurul Hidayah Bostamam, Muhamad Mukhzani Muhamad Hanifah, Mohamad Fariz Mohamad Taib, Mohamad Zhafran Hussin
    Science Letter, 2016;10(2):23-25.
    MyJurnal
    The study is conducted to evaluate the significance of solar irradiance, ambient temperature and relative humidity as predictors and to quantify the relative contribution of these ambient parameters as predictors for photovoltaic module temperature model. The module temperature model was developed from experimental data of mono-crystalline and poly-crystalline PV modules retrofitted on metal roof in Klang Valley. The model was developed and analyzed using Multiple Linear Regressions (MLR) and Principle Component Analysis (PCA) Techniques. Solar irradiance, ambient temperature and relative humidity have been proven to be the significant predictors for module temperature. For poly-crystalline PV module, the relative contribution of solar irradiance, ambient temperature and relative humidity are 64.28 %, 17.45 % and 12.64 % respectively. For mono-crystalline PV module, the relative contribution of solar irradiance, ambient temperature and relative humidity are 66.12 %, 17.46 % and 12.48 % respectively. Thus, there is no significant difference in terms of relative contribution of these ambient parameters towards photovoltaic module temperature between poly-crystalline and mono-crystalline PV module technologies.
  4. Noor Farhana Yusoff, Nor Zaini Zakaria, Hedzlin Zainuddin, Sulaiman Shaari
    Science Letter, 2017;11(1):1-6.
    MyJurnal
    This paper presents the findings of a study to determine the effects of immediate built environment (mounting configuration) on output generated by photovoltaic (PV) module for building integrated photovoltaic (BIPV) and retrofitted PV systems under Malaysian climate. All the systems under study are gridconnected PV (GCPV) system. Eight GCPV systems used in this study; four for BIPV systems and the other four for retrofitted systems. Data for PV module temperature, ambient temperature, plane-of-array solar irradiance and AC power were logged at 5-min interval for all systems. The operating temperature were analysed as the temperature differential with respect to the ambient temperature. The mounting factor was established for both mounting configuration type.
  5. Mohd Hamizan Selamat, Azizah Hanom Ahmad
    Science Letter, 2017;11(1):7-9.
    MyJurnal
    Application of dye-sensitized photoelectrochemical cell (DSSC) was developed using bio-based hybrid polyurethane (PU) polymer and composite electrolyte of Sodium iodide as cation of charge transport. The conducting electron transport material for the regenerative mechanism for Redox couple (I-1/I-3) was due corrosion in contacts of electrode. The polymer as additive has leveraged conductivity level of PU-composite electrolyte prepared by varying amount of Sodium iodide (NaI) via solution casting technique. These properties of composite electrolyte exhibited photoelectrochemical cell that was least corrosive (Block Membrane) for bio-based polymer electrolyte. DSSC design of heterojunction cell requires essential need of functions such as light absorption, charge regeneration -separation and transport to electrodes for a complete cell to work. The addition of polymer composite electrolyte in the redox energy separation of electrical transport was effective for bulk material of the DSSC cell system. The electrical conductivity of electrolyte material was evaluated as fair (x10−5 S.cm-1) using electrical impedance (EIS) with efficiency performance of photo-electro conversion. The hybrid-dye-sensitized solar cell of PU-Cu/TiO2-dye/PU-NaI-I2/B-AC configuration gave a response under light intensity of 100 mW cm−2 with 3.9% conversion efficiency with current density, Jsc of 0.06 mA cm−2 and open circuit voltage, Voc of 0.14 V respectively.
  6. Nurmalessa Muhammad, Nor Zaini Zakaria, Sulaiman Shaari, Ahmad Maliki Omar
    Science Letter, 2017;11(1):10-17.
    MyJurnal
    This paper presents the findings of a study conducted to evaluate the performance and to identify faults of a 10-year old 1.1kW grid-connected photovoltaic (GCPV) system installed at Green Energy Research Center (GERC), Universiti Teknologi MARA (UiTM), Shah Alam. The system performance was evaluated by comparing the real operating field data with the data declared by the manufacturer. Eight performance indicators were used, which are: reference yield, array yield, final yield, capture losses, system losses, performance ratio, PV array efficiency and total efficiency. The fault detection has used three techniques - which were visual inspection as outlined in the International Energy Agency (IEA) document, thermal imager technique and the I-V curve characteristics. The finding for the system performance evaluation gives a 13.2% difference between the real operating field data and the declared manufacturer data. Among the faults detected from the visual inspection are browning and cracks of PV modules.
  7. Mohd Khairul Hazwan Yusof, Azizah Hanom Ahmad
    Science Letter, 2017;11(1):18-23.
    MyJurnal
    Sodium solid electrolyte based on sodium dicyanamide, NaN(CN)2 doped with sodium iodide, NaI was prepared by ultra-fined grinding using planetary milling and pelletised with pellet press. Electrical conductivity and dielectric permittivity study were carried out by Electrochemical impedance spectroscopy (EIS) at frequency range between 50 Hz to 5.00 x 106 Hz. Highest conducting sample at room temperature condition managed to achieved by optimizing the doped sodium salt content with weight composition of 10NaI–90NaN(CN)2 with ionic conductivity value of (5.67 ± 1.26) x 10-4 S cm-1 at ambient temperature condition. The findings are further supported with 10 wt.% NaI in solid electrolyte system sample possessed highest dielectric constant and dielectric loss values at lower frequency region that showed non-Debye behavior for charge storage. Transference number measurement were performed and obtained a value of 0.96 that confirmed the sodium solid electrolyte sample is ionic conductor in nature.
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