Volume volume 25 no.1 2017

This paper explores the possibilities of using liquid electrolyte containing NaClO₄ salt for application of low cost rechargeable sodium-ion batter​ies. Sodium electrolyte, NaClO₄ was prepared by the addition of NaClO₄ salt into organic solvent at various concentration and mixture of organic solvent. The samples were tested using electrochemical analytical meter and Linear Sweep Voltammetry, LSV. The performance of NaClO₄  electrolyte  in half cell configuration with working cathode material were galvanostatically cycled between 2.5 V and 4.0 V at C/10 rate using an automatic galvanostatic charge-discharge unit at room temperature. The NaClO₄ electrolyte showed promising result with conductivity at 10.71 mS/cm in organic solvent of ethylene carbonate (EC) and dimethyl carbonate (DMC) with 1:1 ratio as the best mixture. For cell performance, the Na-ion battery can be cycled near to capacity of 100 mAh/g which has potential to replace lithium-ion battery technology (140 mAh/g) with much cheaper cost offered.

doi: 10.21908/jit.2017.5

Keywords: Liquid electrolyte, sodium- ion batteries, NaClO₄

In this research, we focus on conductivity and electrochemical study of sodium hexafluorophosphate (NaPF₆) electrolyte solution prepared with a mixture of variou​s organic solvent consisting of ethylene carbonate (EC), diethyl carbonate (DEC), dimethylene carbonate (DMC) and propylene carbonate (PC) into binary and ternary system. The ionic conductivity and electrochemical window stability were studied using advanced conductivity meter and linear sweep voltammetry (LSV) respectively at room temperature. The binary system of NaPF₆ electrolyte with EC and DMC (1:1) had resulted in the highest ionic conductivity at 13.14 mS/cm, while the binary system of NaPF6 electrolyte in EC and PC (1:1) had lowest conductivity at 7.72 mS/cm. The highest capacity of 93.99​ mAhg^-1 was obtained from 1.0 M NaPF₆ in of EC and DMC (1:1), while the capacity of 89.25 mAhg^-1 was obtained using 1.2 M NaPF₆ in of EC and DMC (1:1). Half-cell configuration of optimised electrolyte using sodium vanadium phosphate, Na₃V₂PO₄, as working cathode were galvanostatically cycled at room temperature.

 

doi: 10.21908/jit.2017.4
Keywords: Non-aqueous electrolyte, Sodium-ion battery electrolyte, NaPF₆

In non-destructive testing, the acoustic reflectometry provide the relevant information along the propagation path. Bloc​kages and leakages location can be determined by performing flight time calculation. However, greater classification to the type of disconformity can only be solved by time-frequency analysis. Often embedded in the noise, the interpretations of responses is a complicated process that requires time consuming procedures. With the available intelligent learning tools, the analytical stage of classification can be excluded in the procedure. In this work we have adopted a neural network technique to the classification of blockage severities in pipeline from acoustic pulse reflectometry. The responses from open end excitation from experiment are used as the input to the classification of blockage size and trained using neural network. Results are validated using different geometry of blockage insertion. The paper presented the promising prediction performance that can be adapted to other machine learning procedures.

 

doi: 10.21908/jit.2017.2
KEYWORDS: Non-destructive methods, pipeline, pulse reflectometry, soundwave propagation

The construction sector is growing rapidly in Malaysia with a growth of 10.7 % based from the review period of 10^th Malaysia’s Plan (2011-2015). This leads to an increase in demand and production of building materials in the country. One of the ma​in construction materials required is roofing tiles. The public awareness on the concept of green building and the demand for green products is increasing significantly in this country. The aim of this study is to perform a comparison between the clay roofing tiles and concrete roofing tiles in terms of their impact on the environment by using life cycle assessment (LCA) on the roofing tiles that serves to protect the surface area of 1m² using cradle-to-gate approach. The results of the study show that the manufacturing process of concrete tile roofing has less environmental impact compared to the clay roofing tiles.

 

doi: 10.21908/jit.2017.3