Bulletin of Applied Sciences

The effect of rotation and force misalignment of standard load cell on tension/compression testing machine calibration

2023-08-08T15:20:40+07:00

The purpose of this research is to present the effects of load cell rotation and force misalignment during the calibration of a tension/compression testing machine according to ISO 7500-1:2018 (E). A 1000 kN testing machine, resolution 0.5 kN, class 0.5, was calibrated under 3 different conditions: case A, standard load cell was not rotated and force misalignment, case B, standard load cell was rotated to 0 degrees, 120 degrees, and 240 degrees, and case C, standard load cell was not rotated but force misalignment from the force center by 10 mm. When verification of results obtained from three cases was conducted the class of machine range to 0.5 class. The parameters of the test results of case A and B were not different. However, in cases A and C, the relative errors of reversibility were found to be up to -0.45%, and the uncertainty of the calibration at the 95% confidence level were different and increased up to ±0.53%, with respect to the increasing magnitude of the applied force. When comparing the results using E_n number method, the values were found between 0.05 -0.89, and the difference was not significant. When more force was applied, the E_n number increased slightly. This can be concluded that for tension/compression testing machine and standard load cell of a good class, the standard load cell rotation does not affect the calibration, but the force misalignment does.

Automated calibration system for a digital thermo-hygrometer using image processing approaches and wireless communication

2023-08-10T15:26:13+07:00

This research presents an automated calibration system for the calibration of a Digital Thermo-Hygrometer not equipped with a communication interface using digital image processing technology and a real-time wireless communication method to reduce time-consuming calibrations and reduce human errors. This research proposes a solution based on an ESP32-CAM, a small and low-cost camera module, capturing a meter image and transferring it to a web server processing using the seven-segment optical character recognition (SSOCR) method. The measurement and calibration results are presented in a dashboard accessible through the web browser. The experimental results validate the effectiveness of both algorithm and user applications, offering overall performance comparable with manual calibrating processes. In particular, the experimental results on the built-up system show that the proposed image recognition methods provide an average accuracy of 96.48%.

Determination of primary aromatic amines in food contact materials by ultra-high performance liquid chromatography-tandem mass spectrometry

2024-02-20T15:10:47+07:00

The determination of primary aromatic amines (PAAs) in food contact materials involved the examination of ten specific types of PAAS: Aniline (ANL), o-Anisidine (o-ASD), 4-chloro-aniline (4-CA), 4-chloro-o-toluidine (4-COT), 2,6-dimethylaniline (2,6-DMA), 4,4’-methylenedianiline (4,4’-MDA), 4,4-methylenedi-o-toluidine (4,4’- MDOT), 2-methoxy-5-methylaniline (2-M-5-MA), m-phenylenediamine (m-PDA) and o-toluidine (o-T). The extraction solution for PAAs, known as food simulant, was 3% (w/v) acetic acid at 100 °C, which analyzed by ultra-high performance liquid chromatography-tandem mass spectrometry. The method validation according to Eurachem Guide: The Fitness for Purpose of Analytical Methods, 2014, limit of detection and limit of quantitation were 2 and 10 microgram per kilogram, respectively. To prove linearity within the range of 2.00 - 20.0 nanograms per milliliter, each type of PAA was assessed, yielding a coefficient of determination above 0.995. Moreover, accuracy and precision were investigated at 3 concentration levels: 10, 25 and 50 micrograms per kilogram which met the requirement of 2002/657/EC. Therefore, this test method fit in the application of PAAS testing.

The performance test of single-use medical masks: physical characteristics

2024-01-12T10:54:49+07:00

This laboratory report aims to demonstrate methods for testing single-use face masks and report compliance or non-conformity regarding general characteristics, functional properties, and physical characteristics according to the single-use face mask industry product standard requirements (TIS 2424-2565). Physical characteristics testing is based on testing methods according to ASTM F2100-21. The test results showed that the tested mask had a pressure difference of 4 mmH₂O/cm², a resistance to permeability of liquids (synthetic blood) at a minimum pressure of 80 mmHg, face mask flame retardant test was classified in Class 1, and the particle filtration efficiency and bacterial filtration efficiency are 95.7% and 97.6%, respectively. This physical characteristic meets the testing criteria for single-use medical masks, Class 1. They can be tested for biological characteristics to confirm compliance with industrial product standard requirements. As for the study of face mask material properties and structure, results have been reported for manufacturers to analyze and improve to develop product standards further.

The effect of material pretreatment, substrate content, enzyme concentration and extraction time on yield of soluble dietary fiber from asparagus by-product

2024-02-13T09:46:11+07:00

This research aims to study the effect of material pretreatment (temperature and wet blending), substrate content, enzyme concentration (cellulase and hemicellulase) and extraction time on yield of soluble dietary fibers (SDF) from asparagus by-products. This study found that material pretreatment (temperature and wet blending), substrate content, enzyme concentration (cellulase and hemicellulase) and extraction time effected on SDF yield from asparagus by-products significantly (p < 0.05). The extraction condition from this study were material pretreatment of 1:20 (asparagus: water) at 121 °C, 15 lb./sq. inch for 15 min, wet blending to slurry, hydrolysis by using 2.5% (v/w) of cellulase and 2.5% (v/w) of hemecellulase at pH 4.6, 50 °C for 4 h. These condition gave 11.26 ± 0.63% (w/w) of SDF yield. The obtained SDF consisted of 69.06 ± 0.40% (w/w) of total dietary fiber (TDF) which classified to 67.97 ± 0.92% (w/w) of SDF and 1.09 ± 0.53% (w/w) of insoluble dietary fiber (IDF). The obtained SDF had 1.40 ± 0.07 g/g of water holding capacity, 1.64 ± 0.42 g/g of oil holding capacity and 75.45 ± 0.25% (w/w) of water solubility index. Moreover, the obtained SDF had antioxidant activity (IC₅₀ 2.31 mg/mL). These results indicated that these conditions had effect on the potential of SDF extraction from asparagus by-products.

Method validation for simultaneous determination of heavy metals (Hg, Cd, As and Pb) at trace concentration levels in kratom leaves

2024-02-19T08:53:43+07:00

This manuscript reports the validation of an analytical method for simultaneous determination of heavy metals (Hg, Cd, As and Pb) in Kratom at low concentrations (part per billion, ppb) using an inductive coupled plasma-optical emission spectrophotometer (ICP-OES). Sample preparation followed AOAC (999. 10) guideline, involving the microwave digestion of dried Kratom leaves powder with nitric acid and hydrogen peroxide. The linear concentration ranges for Hg, Cd, As and Pb were found to be 0.25 -1.25, 0.05 - 1.25, 0.50 - 12.50 and 0.50 - 12.50 mg/kg, respectively. Limits of detection (LOD) were determined as 0.050 (Hg), 0.010 (Cd), 0.15 (As) and 0.15 (Pb) mg/kg, with corresponding limits of quantitation (LOQ) at 0.25 (Hg), 0.050 (Cd), 0.50 (As) and 0.50 (Pb) mg/kg. The recovery bias showed percentages ranging from 67 - 74% (Hg), 80 - 82% (Cd), 83 - 91% (As) and 80-82 (As). Precision, represented by the percentage of relative standard deviations (%RSD), was within the range of 0.6 - 7.3% for Cd, As and Pb, and 8.2-11.7% for Hg. Additionally, expanded uncertainties for Cd, As and Pb were below ±25%, and for Hg, it was below ±38%, at a confidence level of 95%. These results affirm the reliability and suitability of the proposed method for the quantitative analysis of heavy metals in Kratom leaves.