Recent Science and Technology

VOC Emissions from Natural Latex Pillows: HS-SPME-GC/MS Characterization and Health Implications

Roosanee Kulvijitra, Waraporn Ratsameephaka, Ekwipoo Kalkornsurapranee — Tue, 29 Sep 2026 00:00:00 +0700

Natural rubber pillows are widely used household products; however, their production process may release volatile organic compounds (VOCs) that can affect indoor air quality and human health. This study aimed to identify and characterize VOCs in commercial rubber pillows and evaluate their potential health implications based on toxicological references. Ten pillow samples (P01–P10) were analyzed using headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME–GC–MS). VOC identification was performed by comparison with NIST 14 and Wiley 10 mass spectral libraries, using a match score acceptance criterion of ≥ 90%. Semi-quantification was conducted based on relative peak area normalization. A total of 44 VOCs were identified and classified into nine chemical categories. Frequently detected compounds in all samples included sulfur compounds (e.g., carbon disulfide and benzothiazole); aromatic hydrocarbons (e.g., toluene and styrene); alcohols (e.g., 2-ethyl-1-hexanol and linalool); aromatic compounds (e.g., benzenemethanol, α,α-dimethyl-, and diethyl phthalate); and cyclic alkenes (e.g., α-copaene and δ-cadinene). Benzothiazole and phenol, 2-(1,1-dimethylethyl)-6-methyl-, both considered toxicologically relevant compounds, were consistently detected in all samples. The presence of benzothiazole was attributed to its role in the vulcanization process, whereas amines were observed only in selected samples (P04, P06, P08). Several detected VOCs have been identified as causing potential health risks, including neurotoxicity (carbon disulfide), mucosal irritation (amines), and endocrine disruption (phthalates). These findings indicate that natural rubber pillows may act as sources of diverse VOC emissions, predominantly sulfur- and aromatic-derived compounds. Notably, this is the first study on finished pillows to provide comprehensive evaluations of VOC emissions from them rather than raw materials. Although absolute concentrations were not determined, the results highlight the need for further exposure and risk assessment studies. These findings indicate that natural rubber pillows may act as sources of diverse VOC emissions, predominantly sulfur- and aromatic-derived compounds, particularly under prolonged exposure conditions during sleep. From a practical perspective, these results suggest that manufacturers should consider emission-reduction strategies, including process optimization and the use of low-emission additives, and support the development of eco-labeled, low-VOC products in line with international indoor air quality guidelines in order to enhance consumer safety.

Room-Temperature Vulcanization Time Controls Self-Crosslinking-Driven Self-Healing Behavior in Natural Rubber Sheets

Nasruldin Masae, Korn Taksapattanakul — Tue, 29 Sep 2026 00:00:00 +0700

This study investigated the preparation of natural rubber sheets with self-crosslinking-driven self-healing behavior under controlled curing conditions at room temperature. The work aimed to develop a simpler and more practical approach for producing recoverable rubber materials without complex chemical modification or external heating. Natural rubber sheets were prepared using a sulfur vulcanization casting process under different curing temperatures and curing times. The effects of curing conditions on network formation, swelling behavior, crosslink density, and mechanical recovery were evaluated. Fourier transform infrared spectroscopy was used to monitor changes in the chemical structure during vulcanization. The results showed that increasing curing temperature and curing time promoted sulfur crosslink formation within the rubber network. However, curing at 30 ± 5 ^oC preserved a greater amount of remaining unsaturated bonds and maintained lower crosslink density, which favored polymer-chain mobility during the healing process. The swelling analysis confirmed the gradual development of a denser network structure with increasing curing severity. Mechanical testing demonstrated progressive recovery of tensile properties after the damaged samples were rejoined and healed under room-temperature conditions. Healing efficiency increased continuously with healing time, indicating gradual interfacial recovery through continued network rearrangement and self-crosslinking reactions. The findings suggested that controlled room-temperature curing provided a suitable balance between crosslink formation and chain mobility, allowing recovery behavior to occur without additional external stimuli. This study demonstrated a simple and low-temperature strategy for preparing natural rubber sheets with recoverable mechanical performance and provided useful information for the future development of functional and sustainable rubber materials.

Evaluation of a Commercial β-Mannanase for Konjac Glucomannan Hydrolysis: Activity and Molecular Weight Analysis

Tue, 29 Sep 2026 00:00:00 +0700

β-Mannanase (endo-1,4-β-D-mannanase) is a glycoside hydrolase with potential for producing mannooligosaccharides (MOS), which are recognized for their prebiotic properties. However, the applicability of commercial enzymes to specific substrates such as konjac glucomannan (KGM) remains insufficiently evaluated. This study investigated the hydrolytic activity and estimated the molecular weight of a commercial β-mannanase (Mannanase BGM “AMANO” 10) toward KGM. The enzyme exhibited measurable activity under the tested conditions, with a specific activity of approximately 100,574 U g^-1 protein and a corresponding reducing sugar yield. SDS-PAGE analysis indicated an apparent molecular weight in the range of 50–75 kDa. These findings provide preliminary insights into the performance of the commercial enzyme on KGM and establish baseline information for its potential application in MOS production.

Organic Chinese Radish (Raphanus sativus L.) Cultivation in Raised Beds with Organic Amendments in Thailand

Pattana Somniyam, Vimolchat Somniyam — Tue, 29 Sep 2026 00:00:00 +0700

This study investigated the effects of combining animal manures and plant-based organic amendments on the growth and yield of Chinese radish under raised-bed cultivation in Thailand, in response to the increasing demand for chemical-free produce and national organic farming initiatives. A 3 × 6 factorial experiment arranged in a Completely Randomized Design (CRD) with three replications was conducted using three animal manures (cattle, poultry, and pig manure) and six plant-based residues (copper pod leaves, dried rice straw, rice husk biochar, rain tree leaves, old mushroom lumps, and filter cake). The results showed that animal manures primarily affected stem growth and root yield, whereas plant residues mainly influenced leaf characteristics. The interaction between animal manures and plant residues significantly affected leaf length, leaf biomass, and root size. Pig manure produced the tallest plants (28.94 cm) and enhanced canopy width, leaf dry weight, and root yield (40.26 cm, 19.31 g, 20.46 g fresh weight, and 1.39 g dry weight, respectively). Rice husk biochar significantly increased leaf width, leaf length, and leaf area (5.54 cm, 12.97 cm, and 45.79 cm², respectively). The combination of poultry manure and rice straw resulted in the highest leaf fresh and dry weights (310.54 and 29.34 g, respectively), while pig manure combined with filter cake produced the largest root diameter (64.16 mm), root circumference (19.33 cm), and root fresh weight (31.79 g). In contrast, poultry manure combined with mushroom lumps resulted in reduced growth and biomass accumulation compared with other treatment combinations. These findings demonstrate that appropriate combinations of organic amendments can improve nutrient availability, plant growth, and root development under raised-bed cultivation systems. The study highlights the potential of locally available organic materials for sustainable and chemical-free Chinese radish production in limited cultivation areas.

Physical and Combustion Properties of Charcoal Briquettes Produced from Mangrove Wood and Coconut Shell Waste

Tue, 29 Sep 2026 00:00:00 +0700

This research examines the physical and combustion properties of charcoal briquettes produced from mangrove wood and coconut shell agricultural residues, which were fabricated using a cylindrical compression mould. The seven formulations were prepared with mangrove wood and coconut shell ratios of 100 : 0, 90 : 10, 80 : 20, 70 : 30, 60 : 40, 50 : 50, and 0 : 100. The entire mixture consists of 0.5 kg of tapioca starch (binding agent) and 3 L of tap water. The charcoal briquettes have an outer diameter of 40 mm, an inner diameter of 14 mm, and a height of 80 mm. The properties analysed included physical properties: particle size, true density, moisture content and combustion properties: total heat value, and fuel usage characteristics. The particle size analysis revealed that mangrove charcoal powder had a finer average particle size of 48.2 ± 1.75 µm compared to coconut shell charcoal powder of 285.4 ± 20.36 µm. The true densities of mangrove wood and coconut shell charcoals were 1.3690 ± 0.0019 g/cm³ and 1.4095 ± 0.0016 g/cm³, respectively, indicating similar intrinsic density. Every formulation satisfied the Community Product Standard for Charcoal Briquettes (M.P.Ch. 238/2547) and had a gross calorific value ranging from 5,897 ± 510 kcal/kg to 6,886 ± 420 kcal/kg and a moisture content ranging from 4.211 ± 0.127% to 4.887 ± 0.164%. A higher coconut-shell fraction generally increased calorific value. During combustion, formulation M60C40 ignited fastest (7 min) and had the longest burn-to ash-time, 223 min, making it well-suited for long-duration applications. No formulation produced sparks during usability tests. In summary, the M70C30 formula releases little smoke and provides a consistent medium flame, indicating excellent performance for this research.

Development of Biodegradable Plant Pots from Chitosan Reinforced with Natural Fibers for Agricultural Applications

Thanchanok Kanlaoong, Sopida Jornden, Uraiwan Sookyung — Tue, 29 Sep 2026 00:00:00 +0700

This study aimed to develop biodegradable composite materials based on chitosan reinforced with natural fibers, including pineapple leaf fiber (PL), rice straw (RI), and sugarcane bagasse (BG), for use as biodegradable plant pots. The fibers were incorporated into a chitosan matrix at fiber-to-chitosan ratios of 1:0.08, 1:0.12, 1:0.16, 1:0.20, and 1:0.24 by weight, with glycerol used as a plasticizer. The composites were then fabricated using a molding and drying process. The effects of fiber type and composition on density, water absorption, thickness swelling, and biodegradation behavior were investigated. The results showed that fiber type significantly influenced the composite properties. PL-reinforced composites exhibited the highest density, water absorption, thickness swelling, and biodegradation rate, attributed to their high cellulose content and fibrillated structure. PL-reinforced composites exhibited the highest density (0.907 g/cm³) and biodegradation (97%), attributed to their high cellulose content and fibrillated structure. In contrast, RI composites showed the lowest density and biodegradation, while BG composites demonstrated intermediate behavior. Increasing chitosan content improved dimensional stability by reducing thickness swelling. Soil burial tests confirmed that all composites were biodegradable, with degradation increasing over time. Among the formulations investigated, the fiber-to-chitosan ratio of 1:0.16 was selected as the most suitable formulation for pot fabrication and plant cultivation tests due to its balanced dimensional stability and biodegradation performance. Furthermore, the developed composites were successfully fabricated into hollow pot structures using a two-part mold system. A plant cultivation test demonstrated that all biodegradable pots supported plant growth without visible toxicity and exhibited performance comparable to conventional plastic nursery bags.

Enrichment of Bioactive Compounds from Lotus (Nelumbo nucifera ‘Roseum Plenum’) Tea through Fermentation

Udomrat Chueasuwanachai , Nuntaporn Pungsungvorn, Nipaporn Kanthong — Tue, 29 Sep 2026 00:00:00 +0700

Lotus tea, tea made from the Double red lotus (Nelumbo nucifera ‘Roseum Plenum’). This advantageous characteristic is caused by its bioactive compounds, which include flavonoids and alkaloids. However, stirring the tea with hot water rapidly extracts the active compounds, which may result in a lower overall yield. Additionally, the related flavonoids and alkaloids have good solubility in alcohol. This study aimed to evaluate the feasibility of using lotus tea as a substrate for wine fermentation and to investigate the effect of fermentation on the extraction and enrichment of bioactive compound. Lotus tea and tea infusion used as substrate for the fermentation and HPLC utilized for measuring interesting bioactive compounds. The results indicate that both lotus tea and tea infusion underwent steady fermentation, producing ethanol levels of approximately 6% (v/v) within the first 7 days. All samples displayed characteristics typical of sweet wine, with alcohol content ranging from 6-8% (v/v) by day 28. Fermentation increased the concentrations of bioactive compounds, including catechin, epigallocatechin gallate (EGCG), and nuciferine, to approximately 2–5 times those in the original tea infusion, indicating enhanced extraction during fermentation. While fermentation increased the content of bioactive compounds in lotus tea, further in vivo and clinical investigations are necessary to establish the biological relevance of these findings and assess any potential health effects.

Calcium Ion Adsorption-Desorption Behavior on Maize Residue-Derived Biochar for Soil Nutrient Retention

Patcharee Intanoo, Sakkarin Khaedaeng — Tue, 29 Sep 2026 00:00:00 +0700

This research investigated the adsorption and desorption behavior of calcium ion (Ca²⁺) on maize residue-derived biochar prepared by pyrolysis at 400 °C for 3 h under oxygen-limited conditions. Batch adsorption experiments were conducted by mixing 1.0 g biochar with 30 mL Ca²⁺ solutions at initial concentrations of 50-90 mg/L and shaking at 100 rpm until equilibrium. The produced biochar had an alkaline pH of 8.11, a specific surface area of 22.51 m²/g, a pore volume of 0.04 cm³/g, and oxygen-containing functional groups including -OH, -COOH/C=O, C-O, and phenolic groups. Adsorption equilibrium was reached after 240 min. The adsorption data fitted the Freundlich model (R² = 0.9828; KF = 1.6792 L/g; 1/n = 1.6567) better than the Langmuir model (R² = 0.8478), while negative Langmuir parameters indicated that the monolayer assumption was not appropriate for this system. Kinetic analysis showed better agreement with the pseudo-second-order model (R² = 1.00; qe, cal = 1.170 mg/g), suggesting that surface complexation or ion-exchange interactions contributed to the first adsorption layer. Subsequent retention might involve weaker adsorbate-adsorbate interactions on heterogeneous sites, consistent with Freundlich-type multilayer adsorption. The hysteresis index (HI = 1.37) suggested relatively strong calcium retention with limited desorption in deionized water. These findings indicate that maize residue-derived biochar has potential as a calcium-retention soil amendment; however, soil incubation and plant-response studies are required to validate agricultural performance under practical conditions.

Dual-Heat-Zone Biomass-Assisted Pyrolysis of Polyethylene Waste for Community-Scale Fuel Recovery in Nakhon Phanom, Thailand

Harid Klongdee, Narongrit Uppapong — Tue, 29 Sep 2026 00:00:00 +0700

This study aimed to design, fabricate, and evaluate the performance of a dual-heat-zone (central-pipe), biomass-assisted pyrolysis system for converting polyethylene (PE) plastic waste into pyrolytic oil at rural community scale. The developed system incorporated a central heat-transfer pipe inside the pyrolysis reactor, enabling simultaneous heat transfer from both the bottom (external jacket) and the interior (central pipe) of the reactor. Performance was assessed against a conventional reactor, defined here as a bottom-heated reactor of identical volume, wall material, and PE feedstock loading, heated only through the external jacket The performance was measured based on the reactor temperature profile, cumulative oil yield, and energy efficiency (η), defined as the ratio of chemical energy recovered in the pyrolytic oil to the total thermal energy supplied by the biomass fuel over the run using thermodynamic energy equations (Eq. (3)). Experimental results demonstrated that the system could rapidly increase the reactor temperature from approximately 30°C to 420°C within 20 minutes, and up to 520°C within 30 minutes (mean ± SD, n = 3). The heat transfer rate (Q) from the biomass stove to the reactor reached 15.8 kW, while the cumulative oil yield (Y oil) reached approximately 65% at 30 minutes (± SD, n = 3). Under these specific test conditions (single reactor unit, 5.0 kg PE per batch, n = 3 replicates), the energy efficiency of the pyrolysis system was found to be 68.5%, compared with 42.3% for the conventional bottom-heated reactor tested under the same conditions. These results should be interpreted as preliminary, single-configuration findings rather than generalized performance guarantees. A linear regression analysis was applied to correlate reactor temperature with oil yield (R² = 0.974, P-value < 0.001). Preliminary, non-replicated field observations at two community sites in Nakhon Phanom Province suggested an income-generation potential of approximately 30,000 THB/month, motivating a more rigorous field-trial protocol as a next step. This economic estimate is based on assumptions regarding oil price, daily production volume, and operating cost, as explicitly stated in Section 3.5, and should be treated as indicative rather than confirmed. Preliminary characterization of the pyrolytic oil indicated properties broadly consistent with a diesel-range fuel; full quality data are required before the product is described as a finished “fuel oil.” The fabrication cost of approximately 20,000 THB/unit supports the system's potential viability for community-scale deployment, consistent with the principles of the circular economy and the Sustainable Development Goals. The main limitations of this study include the use of a single plastic type (PE), a single reactor scale, a short 30-minute test duration, and the current lack of data on pyrolytic oil quality and environmental emissions data. These limitations are addressed as priorities for follow-up work.

Natural Rubber Foam for Modular Acoustic Pods: Comparative Acoustic Performance and Full-Scale Prototype Performance Assessment

Natdanai Pratoom, Nattapon Uthaipan — Tue, 29 Sep 2026 00:00:00 +0700

This study investigated the acoustic performance of bio-based natural rubber foam (NR foam) relative to conventional acoustic materials for modular acoustic pod applications through laboratory-scale material screening and full-scale prototype performance assessment. The novelty of this work lies in the introduction of the proposed Normalized Acoustic Performance Index (NAPI), a study-specific composite metric developed to compare the balance between sound absorption and material-level sound transmission resistance, together with a system-level assessment of a full-scale acoustic pod incorporating NR foam. Five materials, including NR foam, polyester fiber, polyurethane (PU) foam, polystyrene (PS) foam, and coconut fiber, were evaluated using impedance tube methods for sound absorption coefficient (SAC) and sound transmission loss (STL). Among the five materials investigated and the selected normalization reference values, NR foam yielded the highest NAPI value of 0.58, indicating the most balanced combination of sound absorption and material-level sound transmission resistance among the tested specimens. A full-scale acoustic pod incorporating NR foam within the wall cavities was subsequently constructed and evaluated under field measurement conditions. The pod exhibited octave-band sound level differences ranging from 37.1 to 49.7 dB, with an arithmetic mean of 42.4 dB across 125–8000 Hz. These values represent the combined acoustic performance of the complete enclosure and do not isolate the individual contribution of the NR foam layer. The developed NR foam exhibited a bulk density of 0.4238 g/cm³, a compressive strength of 80 kPa, a flexible interconnected open-cell structure, and HBF classification under the horizontal burning test conditions employed. Overall, the findings demonstrate the potential of NR foam as a bio-based material providing a balanced combination of sound absorption and material-level sound transmission resistance for modular acoustic enclosure applications.

Plant Community Structure and Carbon Sequestration of the Forest Restoration Areas at Kamnoetvidya Science Academy

Tue, 29 Sep 2026 00:00:00 +0700

This study evaluated the plant community structure, species diversity, and carbon sequestration potential of two distinct forest restoration models at Kamnoetvidya Science Academy, Rayong Province, Thailand. Two silvicultural approaches were observed: (1) Rubber–Palm Intercropping Plots (RPP) and (2) Mixed-Orchard Plots (OP). Vegetation data were collected from 20 x 50 m sample plots in each restoration approach, with each plot subdivided into ten 10 × 10 m subplots, to determine species composition, canopy architecture, and the Importance Value Index (IVI). Biodiversity was quantified using the Shannon–Wiener Index, while biomass and carbon stocks were estimated via established allometric equations. The results revealed higher taxonomic richness in OP (36 species) compared to RPP (25 species), with OP exhibiting higher diversity and evenness indices. Phytosociological analysis identified Hevea brasiliensis as the sole dominant species in RPP, whereas OP displayed a co-dominance of various fruit and indigenous forest species. Despite differences in composition, total carbon stocks were comparable between the two systems, with RPP yielding 45.59 tC/ha and OP yielding 46.23 tC/ha. Carbon distribution was highly concentrated in rubber trees within RPP, while OP exhibited a more heterogeneous distribution across multiple taxa. These findings demonstrate that both integrated agricultural models effectively enhance biodiversity and structural complexity while providing substantial carbon sinks. Consequently, RPP and OP represent viable strategies for rehabilitating degraded agricultural landscapes, contributing to both sustainable land management and global climate change mitigation efforts.

Detection of Chronic Load Imbalance and Hot-Spot Risk in Building Electrical Systems using Long-Term Three-Phase Current Analysis and Mechanism-Informed Artificial Intelligence

Sittisak Rojchaya, Santi karisan — Tue, 29 Sep 2026 00:00:00 +0700

Infrared thermography detects hot spots only at the time of inspection, whereas electrical system degradation evolves continuously through the 24/7 accumulation of operational stress. This study proposes a novel mechanism-informed predictive monitoring framework that integrates long-term three-phase current data with a physics-guided machine-learning inference model to identify early degradation signatures before infrared-detectable heating occurs. Results synthesized from multiple degradation indicators reveal that Phase B exhibits persistent structural dominance, with a mean occupancy of 56% (peaking at 71%), and accumulates 2.35 times the thermal debt of Phase A. This imbalance produces pronounced thermal memory, whereby 38% of thermal stress remains unrecovered after load reduction, resulting in the fastest insulation aging (aging rate = 0.0028; final Aging Index = 0.95). Notably, the proposed system degradation collapse index exceeds the critical degradation threshold (0.70) despite the absence of overload or fault conditions under conventional protection criteria. The proposed framework provides a continuous, low-cost, and practical solution for 24/7 predictive condition monitoring, enabling electrical hazards to be identified before hot spots and failures occur while overcoming the limitations of snapshot-based inspections.