Frontiers in Engineering Innovation Research

Advancement of pozzolanic activity assessment by electrical conductivity measurement techniques: From past to present

2026-07-23T08:15:51+07:00

This article aims to present the evolution and advancement of applying Electrical Conductivity (EC) measurement techniques for evaluating the quality and pozzolanic reactivity of materials, which was developed to overcome the limitations of traditional test methods, such as the Strength Activity Index (SAI), which are time-consuming and often subject to inaccuracies caused by physical impacts (packing effect). The EC technique is a rapid indirect method that monitors the reduction of calcium ions in a Portland cement solution under a controlled temperature of 80 °C, which can classify preliminary material reactivity trends within merely 24–28 hours. Based on relevant studies to date, this technique is widely accepted for analyzing the potential of complex novel alternative materials, such as activated stockpile ashes, agricultural biomass ashes, and binary blends. Statistical data confirm that the reduction in electrical conductivity exhibits a significant correlation with traditional standard test methods. However, this technique still has limitations that require precaution when assessing materials with soluble salts, high calcium content, or hidden calcite. Ultimately, the conclusion of the study indicates that the EC technique is a highly efficient preliminary screening tool, which, when considered in conjunction with chemical composition analysis, will help shorten the research time for new Supplementary Cementitious Materials (SCMs).

Automatic macadamia nut cracker machine

2026-09-17T08:40:09+07:00

This research is to design and build an automatic macadamia nut cracker. The study has two parts: Part 1 involved examining the physical properties of 250 macadamia nuts found that wet standard humidity 12.61%. The mean values and standard deviations for width, length, thickness, and weight were 24.16 ± 1.76 mm, 25.00 ± 1.91 mm, 23.95 ± 1.89 mm, and 7.72 ± 1.66 g, respectively; for the kernels, the corresponding values were 18.99 ± 4.04 mm, 19.86 ± 1.72 mm, 16.05 ± 1.57 mm, and 2.84 ± 0.71 g. The shell hardness was 2,092 N. Part 2 involved the design, assemble, performance testing of the prototype, which consists of three sections. (1) A raw material intake section with a 3 kg capacity that continuously feeds material into the cracking mechanism. (2) A cracking section comprising a cracking head and an impact point. (3) An exit section. The operation begins as macadamia nuts flow from the intake section into the impact receiver's socket. A cracking head strikes the nuts at the uppermost position, driven by a Geneva mechanism synchronized with the movement cycle, causing the shells to fracture before the nuts flow toward the exit section. Statistical analysis at a significance level of 0.05 revealed no significant difference in the percentage of whole kernels obtained across the three cracking speeds or between small and large macadamia nuts (66.07% and 66.83%, respectively); however, a difference was observed for medium-sized macadamia nuts, which yielded a whole-kernel percentage of 53.76%. Cracking capacity was directly proportional to macadamia size and cracking speed; large macadamias achieved maximum capacities of 7.86 ± 0.10, 11.50 ± 0.06, and 15.33 ± 0.35 kg/h at speeds of 2, 3, and 4 rpm, respectively. Economic analysis revealed a break-even sales volume of 13.59 kg for whole kernels, corresponding to a payback period of 16 days.

Valorization of polyphenol-rich extracts from Oroxylum indicum (L.) kurz outer stem bark as sustainable textile colourants: Comparison concerns selected GOTS 7.0 colour fastness criteria on effects of six mordants and pre-, meta- and post-mordanting techniques on dyeing properties

2026-09-14T14:19:37+07:00

The Ban Kham Nang Ok weaving and agricultural community enterprise group in Nikhom Kham Soi District, Mukdahan Province had the main issue of low light colour fastness of cotton yarns dyed with Oroxylum indicum (L.) Kurz. This study examined different mordant conditions to improve the colour fastness of the natural dye and to determine whether the resulting colours met the GOTS 7.0 colour fastness criteria. Greenish brown to khaki were received from those dyeing conditions. From FTIR analysis, it indicated that the bark contains polyphenolic compounds, including flavonoids, hydrolysable tannins, and other phenolic compounds. Pre-mordant copper sulphate, pre-mordant red lime, meta-mordant tamarind, meta-mordant red lime, and pre-mordant iron rust showed top five colour-intensity values respectively. When light, washing, rubbing, and perspiration fastness tests were considered together, post-mordant tamarind and post-mordant iron rust met the GOTS 7.0 colour fastness criteria. Individual colour fastness assessments showed that the post-mordant processes passed 126 out of 144 test results (87.5%), the meta-mordant processes passed 118 out of 144 tests results (81.9%), while the minimum pre-mordant processes passed 109 out of 144 results (75.67%). Selected mordanting conditions achieved light-fastness grades of 4 (fair) or higher, can improve this key limitation of the natural dyes for cotton. These findings identify practical mordanting routes for improving the fastness performance of naturally dyed textiles and support the development of products that comply with GOTS 7.0 colour fastness performance requirements.