Now showing 1 - 10 of 10
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Performance Improvement of The Domestic Refrigerator Using Phase Change Materials
    (2022-01-01) ; ;
    Taweekun, Juntakan
    A growing environmental Impact of global warming and rapidly increasing cost of the electrical energy cause researchers in the field of refrigeration and air conditioning to develop the sustainable cooling technologies. This study investigated the influence of latent heat storage materials on the power consumption and the temperature distribution of a commercial domestic refrigerator. The 2 kg PCMs (Phase change materials) slab of thickness 5 mm, which consisted of a 2:1 by weight mixture of refined paraffin wax and kerosene oil, were located on the back side of the roll-bond evaporator and the copper coated steel tubing coils of the hot-wall condenser, in order to improve the higher performance of refrigerator and to decrease the operating cycle time of the compressor. The experimental and CFD (Computation fluid dynamics) simulation results indicated that the refrigerator equipped with the PCMs storage unit showed a significant enhancement of the system performance and a reduction of the temperature fluctuations in the refrigerator compartment compared to a conventional system. In this investigation, the electric power consumption and the compressor on-time ratio were reduced by 15.69% and 12.13%, respectively. Moreover, the COP (Coefficient of performance) of the refrigeration system was increased by 9.53%.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Bio-Based Wood Adhesives: Current Advances in Polymer Architecture and Structure–Property–Sustainability Integration
    (2026-07-01)
    Dangwilailux, Panya
    ;
    Rachsiriwatcharabul, Natworapol
    ;
    Lakachaiworakun, Putipong
    ;
    ;
    The development of bio-based adhesives has emerged as a viable strategy to reduce fossil-derived resin consumption in wood and wood-based panel applications. This review provides a polymer-focused assessment of adhesive systems derived from proteins, carbohydrates, lignin, and tannins, emphasizing molecular architecture, crosslinking chemistry, interfacial interactions, and structure–property relationships. Adhesive performance is primarily dictated by functional group density, crosslinking efficiency, and network topology. Protein-based adhesives rely on hydrogen bonding and covalent crosslinking with lignocellulosic substrates but require structural modification to improve hydrothermal stability. Carbohydrate-based systems, including starch and cellulose derivatives, offer reactive hydroxyl functionalities that enable oxidation, esterification, and etherification pathways for enhanced network formation. Lignin and tannins, characterized by phenolic and aromatic structures, facilitate condensation reactions and enable partial substitution of phenol in thermosetting resins, supporting low-formaldehyde or formaldehyde-free formulations. Hybrid polymer networks, particularly protein–carbohydrate and lignin-modified systems, demonstrate improved crosslink density, reduced hydrophilicity, and enhanced mechanical performance. Life cycle analyses indicate that increasing biogenic carbon content and minimizing fossil-based cross-linkers can lower global warming potential (GWP) and volatile organic compound (VOC) emissions. Overall, a structure–property–sustainability framework is proposed to guide molecular design and performance optimization of next-generation bio-based wood adhesives.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Mathematical Models of Natural Rubber Sheets Drying: Difference Acid Coagulation Cases
    (2024-05-01) ; ;
    Lakachaiworakun, Putipong
    ;
    Dangwilailux, Panya
    ;
    The mathematical model for drying process is a useful tool in process optimization and drying chamber design. The research purposes of this study were to investigate the influence of drying temperature on drying time and the modelling the drying kinetics of the natural rubber (NR) sheets. The NR sheets which produce from commercial formic acid, commercial acetic acids, and ammonia plus commercial formic acid were studied at drying temperature of 40, 50, and 60°C and air speed of 0.5 m/s. The results indicated that the drying time was substantially reduced with an increase in temperature. The moisture content ratio of rubber sheets produce from commercial formic acid coagulation was similar to the sheets produce from commercial acetic acids coagulation. However, the drying time of them were longer than the drying time of the sheets produce from ammonia plus commercial formic acid coagulation. Finally, the logarithmic model was the best model which suitable to predict the moisture content ratio of the sheets drying with all experimental condition.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Influence of non-straight parallel channel designs on performance of planar SOFC
    (2009-12-01) ; ;
    Charojrochkul, Sumittra
    The flow aerodynamic and friction loss which are usually considered for heat exchanger design are adapted for a channel design for solid oxide fuel cell stack. In this study the design concept is limited to a parallel configuration because of its simplicity. Heat and mass transfer rate can be improved by an introduction of the non-straight parallel channel design yielding higher fuel cell performance. In this paper, a three-dimensional computational model of SOFCs with non-straight parallel channel has been constructed using computational aided engineering tool, FLUENT. The aim of this work is to investigate the cell performance associated with underlying transport phenomena of different channel configurations by looking at distributions of velocity, pressure, hydrogen and oxygen concentrations and current density of each channel design. The influence of each flow channel design (serpentine-parallel, zigzag-parallel and wavy-parallel) on cell performance in SOFCs is discussed. The results indicate that the most enhanced cell performance, especially at high current density, is achieved by using a serpentine-parallel channel design with a trade-off on its greater pressure drop. Copyright © 2009 by ASME.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Characterization of Mixed Biomass Pellet Made from Oil Palm and Para-rubber Tree Residues
    (2017-01-01) ;
    Phetklung, Siwimon
    ;
    Jakaew, Watcharakit
    ;
    Chumuthai, Songamorn
    ;
    Sriam, Phurinut
    In this study, the potential of the important economic crops of Southern Thailand for pellet making was utilized. The biomass pellets were prepared from oil palm leaves (PL) and frond (PF), para-rubber leaves litter (PAL) and branch (PB) and their blend (mixing of 50 wt.% of two materials). The raw materials which collected from local plantation were cleaned, dried and milled into small particles less than 1 mm and then continued with pellet forming by a single unit press in a laboratory under the temperature and pressure of 130°C and 350 psi. Some characteristics were analyzed to evaluate quality of pellet, i.e. moisture content, density, ash content, calorific value. Moreover, the combustion behavior was investigated by means of thermogravimetry analysis. The lowest ash content of 2.27% and 2.82% were received from PB in case of pure pellet and PB+PAL in case of mixed pellets, respectively. The calorific values of pure pellets were 16.05, 17.68, 18.71 and 19.64 MJ/kg for PF, PL, PB and PAL, respectively. The combustion characteristics were exhibited in the ignition and burnout temperature, which drawn from TG curved. The burnout temperature was improved with higher in all cases of mixed biomass pellet. The characteristics of mixed biomass pellets differed from pure biomass pellets which contribute to the further improve its quality.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    A Review of the Parameters Related to the Rubber Sheets Production: Major Constituents of Rubber Latex, Rubber Particles, Particle Interaction of Rubber Latex, Rubber Porous Structure, Rubber Drying Kinetics and Energy Consumption
    (2023-01-01) ; ;
    Dangwilailux, Panya
    ;
    ;
    Taweekun, Juntakan
    Natural rubber (NR) is obtained principally from Para-rubber trees of the species Hevea brasiliensis which grow in tropical regions. Using ultra-centrifugation method, fresh latex (FL) from Para-rubber trees can be mainly divided into four fractions; an upper white layer consists of rubber particles, Frey-Wyssling particles in a yellow or an orange layer, C-serum phase and lutiods particles in the bottom fraction [1-3]. The averages of rubber particles have diameters of 0.02 to 3.0 micron, and they are protected by a complex film containing lipids and proteins [4-8]. The main forces of attraction between neighboring rubber particles in latex system can be divided into five force types; Structural Forces (SF), Van der Waals Interaction (VWI), Electrostatic Force (EF), Exclusion Interaction (EI) and Polymer-Polymer Interaction (PPI) [9]. The porous model of rubber structure used to describe moisture transfer was based on the existence of two different regions referred to as non-hygroscopic region and hygroscopic region. The rubber products drying always produced a considerable shrinkage effect which considered in the physical of the product, such as the diffusion coefficient, mass and heat transfer. An initial moisture content of raw material, the experimental temperature and the drying equipment had affect to the EMC isotherms and the drying kinetics. Finally, discussions on the implications of the results for strategies to reduce the energy consumption in RSS and STR20 block rubber are also presented.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Non-reacting flow distributions under various SOFC stack configurations
    (2007-12-01) ; ;
    Phoocharoen, Niwat
    ;
    Charojrochkul, Sumittra
    A 3-dimensional Computational Fluid Dynamics (CFD) model for fuel cell stack simulations has been developed using STAR-CD with effect of buoyancy force. A flow distribution in a planar fuel cell stack with straight gas channels is considered with variation in gas feeding directions. Any electrochemical interaction is neglected. Eight flow configurations comprising of three parameters were investigated, i.e.; i) vertical and horizontal orientations of the cell stack, ii) U-shape and Z-shape flow patterns, and iii) upward and downward feeding directions. For these configurations, the velocity distributions across the stack were compared. The better flow distribution was observed for air with U-shape flow pattern and upward feeding. For fuel side, the flow with U-shape downward yields a relatively better flow distribution. Moreover, the results indicate that the effect of feeding direction is small in the stack with Z-shape flow. © The Electrochemical Society.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Thin-Layer Drying Model and Antifungal Properties of Rubber Sheets Produced with Wood Vinegar as a Substitute for Formic and Acetic Acids
    (2025-05-01) ;
    Lakachaiworakun, Putipong
    ;
    Rachsiriwatcharabul, Natworapol
    ;
    ;
    Dangwilailux, Panya
    Currently, workers in the ribbed smoked sheet (RSS) rubber production industry face increasing health risks, primarily due to their direct involvement in converting fresh latex into raw rubber sheets. This process involves the manual addition of appropriately diluted commercial formic acid and acetic acid to induce coagulation, resulting in a tofu-like consistency, which is subsequently processed into rubber sheets. Previous studies have indicated that the use of commercial formic and acetic acids poses significant health hazards to workers and contributes to environmental pollution. Therefore, this study explores the feasibility of replacing commercial formic and acetic acids with wood vinegar derived from para-rubber wood, bamboo, and eucalyptus in the RSS production process. Wood vinegar samples from the three biomass sources were analyzed for their organic compound compositions using gas chromatography and subsequently used as coagulants in the preparation of raw rubber sheets. The drying kinetics and antifungal properties of the resulting sheets were then evaluated. The results revealed that wood vinegar derived from para-rubber wood contained the highest concentration of acetic acid (41.34%), followed by bamboo (38.19%) and eucalyptus (31.25%). Rubber sheets coagulated with wood vinegar from para-rubber wood and bamboo exhibited drying kinetics comparable to those obtained using acetic acid, with the two-term exponential model providing the best fit. Conversely, rubber sheets coagulated with eucalyptus-derived wood vinegar, which had a relatively high concentration of phenolic derivatives (22.08%), followed drying behavior consistent with the Midilli et al. model, similar to sheets treated with formic acid. In terms of antifungal properties, five fungal genera—Aspergillus, Penicillium, Fusarium, Trichoderma, and Paecilomyces—were identified on the rubber sheets. Fungal growth was most pronounced in the control samples (untreated with wood vinegar), whereas samples treated with wood vinegar exhibited significantly reduced fungal colonization. These findings indicate that wood vinegar is effective in inhibiting fungal growth on the surface of rubber sheets and may serve as a safer and more environmentally friendly alternative to commercial acid coagulants.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Sound Absorption Properties of Natural Fiber Composite from Areca Nut Shells Fibers with Polyvinyl Alcohol
    (2025-01-01) ; ;
    Rachsiriwatcharabul, Natworapol
    ;
    ;
    Dangwilailux, Panya
    This research investigates the development of sound-absorbing composites using areca nut shells fibers (ANS) bonded with polyvinyl alcohol glue, aiming to create an environmentally friendly and sustainable alternative to conventional synthetic materials. The research explores the effects of varying thicknesses (10, 20, and 30 mm) and fiber lengths (10, 20, and 30 mm) on the sound absorption performance of the composites. The sound absorption coefficient (SAC) was measured using the impedance tube method to determine the composites’ effectiveness across different frequency ranges. The results indicate that the thickness of the composite significantly enhances sound absorption, particularly in the low-frequency range (1,500–2,500 Hz). Composites with a fiber length of 30 mm demonstrated the most effective sound absorption properties at 0.90 above 1,600 Hz (ANS-T30-L30). Additionally, blending fibers of different lengths led to SAC changed behavior. This study contributes to the growing body of knowledge on sustainable materials by utilizing agricultural waste to produce functional and eco-friendly sound-absorbing composites.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Effects of Wood Vinegar as a Coagulant in Rubber Sheet Production: A Sustainable Alternative to Acetic Acid and Formic Acid
    (2025-07-01) ;
    Lakachaiworakun, Putipong
    ;
    Rachsiriwatcharabul, Natworapol
    ;
    ;
    Occupational exposure to commercial formic and acetic acids through dermal contact and inhalation during rubber sheet processing poses significant health risks to workers. Additionally, the use of these acids contributes to environmental pollution by contaminating water sources and soil. This study investigates the potential of three types of wood vinegar—derived from para-rubber wood, bamboo, and eucalyptus—obtained through biomass pyrolysis under anaerobic conditions, as sustainable alternatives to formic and acetic acids in the production of ribbed smoked sheets (RSSs). The organic constituents of each wood vinegar were characterized using gas chromatography and subsequently mixed with fresh natural latex to produce coagulated rubber sheets. The physical and chemical properties, equilibrium moisture content, and drying kinetics of the resulting sheets were then evaluated. The results indicated that wood vinegar derived from para-rubber wood contained a higher concentration of acetic acid compared to that obtained from bamboo and eucalyptus. As a result, rubber sheets coagulated with para-rubber wood and bamboo vinegars exhibited moisture sorption isotherms comparable to those of sheets coagulated with acetic acid, best described by the modified Henderson model. In contrast, sheets coagulated with eucalyptus-derived vinegar and formic acid followed the Oswin model. In terms of physical and chemical properties, extended drying times led to improved tensile strength in all samples. No statistically significant differences in tensile strength were observed between the experimental and reference samples. The concentration of acid was found to influence Mooney viscosity, the plasticity retention index (PRI), the thermogravimetric curve, and the overall coagulation process more significantly than the acid type. The drying kinetics of all five rubber sheet samples displayed similar trends, with the drying time decreasing in response to increases in drying temperature and airflow velocity.