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The purpose of this study was to investigate the effect of working volume in the high-energy ball-milling process on the breakage characteristics (i.e., particle size, morphology, and chemical composition) and adsorption performance of rice straw ash. This study was conducted to confirm working volume issue since this parameter has correlations with the scaling-up process, the amount of input/output in the ball-milling process, and the breakage characteristics of the material. Rice straw ash was selected as a model of size-destructed material because this material is porous and chemically and thermally inert; thus, the evaluation can be effectively done without any chemical reaction and time-consuming process. To obtain the outcome precisely, the study varied working volume under constant other processing parameters (i.e., ball-to-rice straw ash, milling speed/rotation, temperature, ball size) in the batch-typed conventional ball-milling process. The results showed that the ball-milling process is effective to reduce particle sizes to several micrometers and further nanometers. Precise control of the final particle size was achieved by the adjustment of working volume, in which the less working volume results in the generation of smaller particles. The prospect control of final particle size is due to the control of shear stress and collision phenomena during the ball-milling process. The evaluation was also completed with theoretical approximation and adsorption performance of the product. In addition to varying working volume, this study examined the product yield since it can be a contributive factor to determine the optimum condition of the ball-milling process.

Fourier Transform Infrared (FTIR) has been developed as a tool for the simultaneous and quantitative determination of organic components, including chemical bond, as well as organic content (e.g. protein, carbohydrate and lipid). However, until now, there is no further information for the detailed information in the FTIR peaks. The objective of this study was to demonstrate how to read and assess chemical bond and structure in the organic material. The analysis was then compared with the literatures. The step-by-step method on how to read the FTIR data was presented, including reviewing simple to the complex organic materials. This study is potential to be used as a standard information on how to read FTIR peaks in the biochemical and organic materials.

The purpose of this study was to demonstrate a simple, rapid analysis, portable, and inexpensive spectrophotometer. Different from other spectrophotometers, the present instrument consisted of a single white light-emmiting-diode (LED) as a light source, a light sensor, and arduino electronic card as an acquisition system. To maintain a constant light intensity, a common white-color LED emitting a 450-620 nm continous spectrum was employed. Software was written in C++ to control photometer through a USB interface and for data acquistion to the computer. The instrument is designed to be simple and compacted with sizes of 200 x 130 x 150 mm for length, width, and height, respectively. The analysis of the total cost isabout less than 500 USD, while commercially available offers price of more than 10,000 USD. Thus, this makes the present instrument feasible for teaching support media in developing countries. The effectiveness of the present spectrophotometer for analyzing solution concentration (i.e. curcumin) was also demonstrated. Interestingly, the present spectrophotometer is able to measure the concentration of curcumin precisely with an accuracy of more than 90%. Different from commercially available standard UV-visible spectrophotometers that have limitations in the analysis of concentration of less than 50 ppm, the present system can measure the concentration with no limitation since the measurement is based on the LED light being penetrated.