Bulletin of Applied Sciences

A study of the shock wave behavior using the shadowgraph technique

Wuttichai Sittiwong — 2025-06-26

The purpose of the research is to study the differences shock waves behavior, the cylindrical projectile of following five head shapes are assigned: 1) flat shape head, 2) round nose head, 3) flat nose head, 4) 30º boat tail head, and 5) 45º boat tail head shape. The projectile driven with 3 grams of smokeless powder. The behavior of the shock waves recorded using the shadowgraph technique in conjunction with a high-speed video camera. According to the results of the experiment, the shadowgraph technique combined with a high-speed video camera can clearly record the behavior of the shock waves from the projectiles. In addition, the projectile velocity is divided into two groups according to the shape of the bullet: flat shape, round nose headed, and flat nose head projectile. It has a similar average speed of about 780 meters per second. The group including projectiles with 30º, and 45º boat tail shapes had a velocity of around 550 m/s. It has an average speed of about 550 meters per second.

Determination of cadmium in paper for food contact by inductively coupled plasma mass spectrometry

Nootjarin Phonhong — 2025-06-26

This work proposed the method validation for cadmium (Cd) determination in paper for food contact material (FCM). The paper based FCMs was digested using microwave digestion in acidic condition. After that, Cd was analyzed by inductively coupled plasma mass spectrometry (ICP-MS). It is necessary that the laboratory has to validate testing method to evaluate whether the validated method is fit for intended use. The performance characteristics were studied including instrument working range, limit of detection (LOD), limit of quantitation (LOQ), bias, intermediate precision, matrix effect and measurement uncertainty. Under the studied condition, the linearity in the range of 0.040 – 0.40 mg/kg with the correlation coefficient (r) of 0.9999 was obtained. The LOD and LOQ were 0.0024 mg/kg and 0.040 mg/kg, respectively. The bias and precision studies showed that percentage of recovery and relative standard deviation (RSD) of Cd were between 86.5 – 92.1% and less than 10%, respectively. Moreover, the expanded uncertainty of the proposed method was less than ±20% at the confidence level of 95%. Thus, it can be concluded that this test method for Cd determination in paper based FCM was valid and fit for the intended use.

Active substances in cleaning and disinfecting products from Thailand's online market in 2023

Neungrutai Saesaengseerung — 2025-06-26

Cleaning and disinfecting products contain active ingredients such as acid, active oxygen, and hypochlorite that are chemical products are easily accessible to the public and widely used. Although the quality of these products has been registered by responsible Thailand government agency before placing on market for sale, post-market surveillance is still important; especially checking the amount of active ingredients mixed in these products. It is because the amount of substances that do not match the product label may affect cleaning and disinfecting effectiveness. Therefore this research focused on randomly sampling of 59 products, which divided into 3 groups according to active ingredients such as acid, active oxygen, and hypochlorite for 21, 21, and 17 samples, respectively. Acid-base titration method was used to quantify amount of hydrochloric acid in acid cleaning products and redox titration method was used to determine amount of active oxygen (calculated as H₂O₂) and available chlorine in the latter two groups of products, respectively. The survey results found that only 42% of hydrochloric acid products and 29% of active oxygen products among the sampled items were detected with hazardous substance registration numbers and had active ingredient levels that matched those specified on their labels and met the criteria set by Thai industrial standards. However, none of the hypochlorite products had available chlorine levels that matched those stated on their labels.

Method validation for determination of piperine in black pepper by high performance liquid chromatography

Thidarat Kruatian — 2025-06-26

The determination of piperine in black pepper samples using High performance liquid chromatography (HPLC) was successfully performed and validated. The method demonstrated specificity and good linearity in the concentration range of 1 - 6 mg/L with a coefficient of determination (R²) of 0.9998. Accuracy was evaluated through %recovery studies and obtaining results between 100.25 - 101.65%. The precision expressed as a relative standard deviation (%RSD), showed good repeatability for both intra-day and inter-day analyses, with %RSD values less than 5%. The limit of detection (LOD) and the limit of quantitation (LOQ) were 0.99 and 1.09 mg/L, respectively. The linearity, percent recovery, precision, LOD and LOQ values were acceptable and complied with AOAC guidelines for single laboratory, validation of chemical methods for dietary supplements and botanicals. Measurement uncertainty was calculated as 3.49% at a 95% confidence interval (k=2). All results presented that the method was reliable and suitable for the determination of piperine in black pepper sample. Subsequently, 28 black pepper samples from various sources were analyzed using a validated method. The results showed that piperine content ranged from 3.15% to 6.41% w/w, with 20 samples (71.4%) meeting the Thai Industrial Standard (TIS. 297-2556) requirement of piperine content ≥4%. The results demonstrate that the proposed HPLC technique for analyzing piperine content in black pepper samples is effective and can be applied to samples from various sources. Furthermore, the data from this study can serve as a guideline for the quality control of Thai herbal raw materials and extracts, ensuring compliance with standard requirements and enhancing global competitiveness.

The effect of extraction methods and Centella asiatica species on yield, total phenolic content and antioxidant activity of extract

Rewadee Meesat — 2025-06-26

This research aims to study the comparison of extraction methods for local Asiatic Pennywort or Centella asiatica species. The extract techniques were divided into three methods, water extraction, enzyme extraction, and ethanol extraction.The local Centella asiatica species, Nakhon Pathom, Rayong, and Ubon Ratchathani species were used as extracted samples. The extracted products were evaluated for extraction yield, total phenolic content (TPC) and antioxidant properties using DPPH assay and ferric reducing antioxidant power (FRAP). The Water extraction method was performed at 95 ºC for 60 min and enzyme extraction method was applied Viscozyme L 3% (w/w) at pH 5.0, and 50 ºC for 60 min. Additionally, the ethanol extraction method was carried out at 25 ºC for 60 min. This study found that the extraction methods and the C. asiatica species had a significant effect on the extracted yield, TPC and antioxidant activity (p<0.05). The highest yield could be extracted by the enzyme extraction, follow by the water and ethanol extraction method, respectively. However, the TPC and antioxidant activities of the extract products obtained from the water and ethanol extraction method exhibited significantly higher than those from the enzyme extraction method (p<0.05). The Rayong species gave a significantly higher extraction yield, TPC and antioxidant activity compared to Nakhon Pathom and Ubon Ratchathani species (p<0.05). Thus, the appropriate extraction technique and C. asiatica species were the water extraction method and the Rayong specie. The water extraction was used to extract active compounds from the local specie, yielding 35.94 ± 0.54%(w/w). The TPC was 36.02 ± 0.51 mg GAE/g, while the IC₅₀ and FRAP values were 0.16 ± 0.01 mg/mL and 727.38 ± 27.47 µmol Fe²⁺/g, respectively. The extract of Centella asiatica showed high solubility in water and could be applied as an ingredient for food and drink products.

Quality assurance for the production and performance testing of alcohol gel for hand sanitizers

Nusara Yinyom — 2025-06-26

The demand for alcohol-based hand sanitizers containing at least 65% alcohol by weight has increased. However, the quality of these products has often been inconsistent. This research aims to ensure the quality of alcohol gel production and to test the efficiency of alcohol measurement devices in the factory. Two critical control points (CCPs) have been identified. The first critical control point (CCP1) involved verifying the quality of the main raw materials - denatured alcohol, gelling agents, and pure water by utilizing the certificate of analysis results to ensure compliance with acceptance criteria. The second critical control point (CCP2) was to measure the alcohol content before packaging using an alcohol hydrometer with an accuracy of no more than 1.25%. This measurement required a sample prepared with 5M hydrochloric acid (HCl). Additional control points include the accuracy and precision of the balances, as well as the cleanliness and neutrality of the glassware and mixing equipment. All processes were traceable via a digital data recording system, implemented using spreadsheet software (e.g. Microsoft Excel), to ensure reproducibility. The final product could be stable, with a pH of 5.8 and an ethanol content of 77% by volume. The product was considered bactericidal effective when log reduction (lg R) of the reference bacterial amount after one minute contact time was ≥ 5. This quality assurance process in alcohol gel production ensures compliance with legal standards and guarantees product effectiveness.