KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Search Results

Now showing 1 - 10 of 10

Some of the metrics are blocked by your
consent settings
Hybrid-AI-sep: A multi-agent computer-aided tool for separation process problems solving and learning
(2026-06-01)
Prasopsanti, Kris
;
Yadbantung, Rungroj
;
Phanusupawimol, Thunyaras
;
Areerat, Surat
;
Mansouri, Seyed Soheil
AbstractThis paper presents a multi-agent based and artificial intelligence augmented computer-aided software tool, Hybrid-AI-sep, with problem solving and education modules for the important topic of design of separation operations. Three types of agents are employed by Hybrid-AI-sep, a library of knowledge-tools containing theory, concepts, and glossary terms related to separation operations; a library of database tools consisting of different types of measured data; and a library of computational tools that generate problem specific data that may be needed for decision making and explanation for the problem solution and educational modules. The paper presents software architecture together with examples of the three types of agents. Illustrative examples highlighting various features of Hybrid-AI-sep are given in the main manuscript and the supplementary material.
Some of the metrics are blocked by your
consent settings
How Can an Appropriate CFD Model be Developed for Turbulent Flow in Rough Pipes?: Evidence from Friction Factor Prediction
(2026-01-01)
Boonsamer, Kraiwit
;
Temsiriphan, Barami
;
Thongnoi, Piyawut
;
Areerat, Surat
;
Bumrungthaichaichan, Eakarach
This paper answers the question: “How can an appropriate turbulent rough pipe flow computational fluid dynamics (CFD) model be developed?” The Reynolds-averaged Navier-Stokes equations with the standard k-epsilon turbulence model and scalable wall functions were solved to obtain Fanning friction factors and mean velocity profiles in inflectional and monotonic rough pipes. CFD models with near-wall grid sizes from four dimensionless wall distances and two roughness treatment approaches were simulated. Eight roughness Reynolds numbers, covering the lower end of the transitionally rough regime through the fully rough regime, were studied for each roughness type. Appropriate roughness and turbulence model constants for turbulent rough pipe flows in the transitionally rough regime were determined. For model validation, the predicted mean axial velocity profiles for Reynolds numbers of 5 × 104 and 5 × 105 exhibited good agreement with the reference experimental data. A total of 208 CFD simulations (32 from our previous works and 176 from the present study) were analyzed. Finally, based on comparisons between predicted Fanning friction factors and established correlations, appropriate CFD models for turbulent flows in inflectional and monotonic rough pipes were identified. Suitable CFD models for accurately predicting mean velocity profiles at roughness Reynolds numbers below 11.225 were also obtained, although with the caution that improved mean velocity prediction may reduce Fanning friction factor accuracy. Furthermore, the present CFD work provides essential guidance for extending simulations to other rough surface types and rough-wall flow situations.
Some of the metrics are blocked by your
consent settings
Solvent Selection for Mitragynine Extraction by Hansen Solubility Parameter
(2023-01-01)
Ditthapornset, Sirawich
;
Lerkkasemsan, Nuttapol
;
Areerat, Surat
Mitragyna speciosa (Korth.) Havil., commonly known as “Kratom” has a wide range of therapeutic benefits. In this research study the solvents that can be used to extract Mitragynine from kratom leaves. To predict solubility parameters, Hansen solubility parameters were employed. Then analyzing the solubility parameters using the ProCAPE application However, Mitragynine cannot directly determine the solubility. Instead, a method for evaluating the solubility from derivatives of Mitragynine was used in this study. A ternary graph shows the solubility of the derivatives and solvents. The solvents selected were considered for safety from the GSK’s Solvent Selection Guide. From the results, it was found that several types of solvents which that were dissolved derivatives of Mitragynine better than conventional solvents. Additionally, while using ProCAPE, the solubility parameters were predicted from extraction-related research was applied, and the results were shown as ternary graphs. The graphs were confirmed to be in accordance with the experimental data from the research that was collected.
Some of the metrics are blocked by your
consent settings
Enhancement of molecular weight reduction of natural rubber in triphasic CO2/toluene/H2O systems with hydrogen peroxide for preparation of biobased polyurethanes
(2019-01-28)
Duereh, Alif
;
Boonchuay, Chokchai
;
Buahom, Piyapong
;
Areerat, Surat
Molecular weight reduction of natural rubber (NR) with hydrogen peroxide (H<inf>2</inf>O<inf>2</inf>) oxidizing agent is limited in biphasic water-toluene systems that is attributed to mass transfer. In this work, CO<inf>2</inf> was applied to the (aqueous H<inf>2</inf>O<inf>2</inf>)-(toluene-NR) systems with the objective of improving reaction efficiency. Experiments were performed on the reaction system with CO<inf>2</inf> at 12 MPa and at reaction temperatures and times of 60°C-80°C and 1 h-10 h to evaluate the reaction kinetics. CO<inf>2</inf> could enhance the NR molecular weight reduction by lowering the activation energy (from 121 kJ·mol-1 to 38 kJ·mol-1). The role of CO<inf>2</inf> in the reaction system seems to be the formation of oxidative peroxycarbonic acid intermediate and promotion of mass transport due to the reduction in the toluene-NR viscosity and interfacial tension. The epoxidized liquid NRs (M<inf>n</inf>=4.9×103 g·mol-1) obtained from NR molecular weight reduction was further processed to prepare hydroxyl telechelic NR (M<inf>n</inf>=1.0×103 g·mol-1) and biobased polyurethane.
Some of the metrics are blocked by your
consent settings
The Effects of Foaming Conditions on Plasticized Polyvinyl Chloride Foam Morphology by using Supercritical Carbon Dioxide
(2018-01-01)
Chuaponpat, Natthapong
;
Areerat, Surat
This research studies the effects of foaming conditions by using supercritical (scCO<inf>2</inf>) as a physical blowing agent on plasticized polyvinyl chloride (PVC) foam morphology. Foaming conditions were foaming temperature of 40, 60, and 80 oC, foaming pressure of 120, 150, and 170 bar at constant soaking time of 30 min. Depressurization was employed to activate nucleation and samples were cooled at room temperature about 30 oC for stabilization, which cause shrinkage behavior. PVC foam samples were calculated percentage of shrinkage (Sh) by using density at before and after aging process at 30 oC for 12 h to make sure for completely permeation of air into foam structure. PVC foam by using scCO<inf>2</inf> as a physical blowing agent reveal uniform closed bubble and regular foam structure with thin bubble wall (less than 5 μm). At high solubility of scCO<inf>2</inf>, PVC foam samples contain bubble diameter with less than 20 μm and high bubble density within the range of 108 - 1011 bubbles/cm3. PVC foam samples at low solubility foaming conditions display a large bubble diameter (more than 140 μm) and lower bubble density (106 bubbles/cm3). These foam samples are be able to reduce the density about 75% when compared with unfoamed sample but it structure highly shrink with Sh more than 50%.
Some of the metrics are blocked by your
consent settings
Preparation of natural rubber-based polyol by oxidative degradation under supercritical carbon dioxide for flexible bio-based polyurethane foams
(2016-11-01)
Amnuaysin, Thidarat
;
Buahom, Piyapong
;
Areerat, Surat
Nowadays, polyurethane foams play a key role in widespread applications, and their market demand is still growing globally. This work aims to prepare hydroxyl telechelic liquid natural rubber, a bio-based polyol, as a sustainable raw material and to enhance elastic properties of soft segment bio-based polyurethane foams. A hydroxyl telechelic liquid natural rubber with a viscosity-average molecular weight of 4.2 × 103g/mol was successfully produced by oxidative degradation of natural rubber with hydrogen peroxide in the presence of supercritical carbon dioxide, then modifying the chain-end functionality to obtain hydroxyl number of 59 mg KOH/g. The functionality of hydroxyl telechelic liquid natural rubber was confirmed by FT-IR and 1H-NMR. Bio-based polyurethane foams were then prepared by mixing the synthesized hydroxyl telechelic liquid natural rubber with commercial diisocyanate. Morphological properties and thermal stability of polyurethane foams were investigated.
Some of the metrics are blocked by your
consent settings
Effect of moisture on the mechanical properties of glass fiber reinforced polyamide composites
(2016-05-01)
Chaichanawong, Jintawat
;
Thongchuea, Chanchai
;
Areerat, Surat
The effect of moisture on the mechanical properties of glass fiber reinforced polyamide composites was investigated. The composites of short glass fiber/polyamide with different weight percent (0-30 wt%) were prepared. To investigate the effect moisture on mechanical properties of these composites, the specimens were prepared and then immersed in distilled water for a period of 60 days. The weight changes of the specimens were daily measured to determine the amount of moisture absorption of the specimens. Tensile test and flexural test were conducted based on ASTM D638-02a and ASTM D790-02, respectively. The effect of moisture on the microstructure of the composites was also investigated. The moisture absorption of the glass fiber reinforced polyamide composites could be divided into four stages: (I) the beginning stage (1-7 days), (II) the second stage (8-24 days), (III) the third stage (25-35 days) and (IV) the saturated stage (36-60 days). Yield strength, ultimate tensile strength and flexural strength of all specimens significantly decreased at the beginning stage of moisture absorption and then these mechanical properties were almost constant. The modulus of elasticity of all specimens decreased at the beginning stage and saturated stage. In addition, ductility (%Elongation) of all specimens did not change at the beginning stage. However, ductility of all specimens significantly decreased in the third stage, and then their ductility were almost constant. Based on the microstructure analysis, the results indicated that the transition of brittle to ductile properties of the glass fiber reinforced polyamide composites after moisture absorption would be attributed to the changes in their mechanical properties.
Some of the metrics are blocked by your
consent settings
The effects of processing parameters on the residual wall thickness distribution at the sharp angle corner of water assisted injection molded parts
(2013-11-11)
Pudpong, T.
;
Buahom, P.
;
Areerat, Surat
;
Rungseesantivanon, W.
;
Satoh, I.
Water-assisted injection molding (WAIM) has been widely used for tubular plastic parts due to its advantages of relatively low cost and fast cycling time. However, the non-uniform distribution of the wall thickness, especially at the sharp corner, is still a basic problem in the WAIM process. This work presents the effects of sharp corner angles on wall thickness distribution in sections near corners for various processing conditions of the WAIM process, including melt temperature, mold temperature, water delay time, water holding time, and holding pressure. Three grades of polypropylene (PP) resins with different melt flow indices were studied using seven mold geometries that varied the angle of the sharp corner section. The wall thickness distribution at the corner sections were characterized in terms of inner and outer residual wall thicknesses, hollow core ratio, and the percentage of difference between the inner and outer wall thicknesses. In addition, computational fluid dynamic simulations with Moldflow Plastics Insight version 4.1 were performed for each sharp corner angle. It was found that the wall thickness distribution of the straight tube was more uniform than those of the curve tubes. Water injection delay time and water pressure were the major parameters that had a significant impact on the hollowed core ratios, while the percent difference between inner and outer wall thicknesses was mainly influenced by melt temperature. © Carl Hanser Verlag GmbH & Co. KG.
Some of the metrics are blocked by your
consent settings
Preparation of carbon aerogel microspheres by a simple-injection emulsification method
(2013-09-01)
Chaichanawong, Jintawat
;
Kongcharoen, Koranit
;
Areerat, Surat
Carbon aerogel microspheres were successfully prepared using a simple-injection emulsification method, employing sol-gel polycondensation of a resorcinol-formaldehyde solution containing sodium carbonate as a catalyst. This process was followed by solvent exchange using acetone, supercritical drying with carbon dioxide and carbonization in a nitrogen atmosphere. The effect of curing time before starting injection, injection rate and agitation rate of continuous phase on the particle size and the porous properties of the carbon aerogel microspheres was investigated. Adsorption of phenol by using the prepared carbon aerogel microspheres was also examined. The diameter of carbon aerogel microspheres was controlled in the range of 20-55 μm by varying injection rate and agitation rate. The mean diameter of carbon aerogel microspheres decreased with increasing the injection rate and the agitation rate, whereas their mean diameter was independent of the curing time. The BET surface area and total pore volume of carbon aerogel microspheres increased with increasing the curing time. In contrast, their BET surface area and total pore volume decreased with increasing the injection rate and the agitation rate. The BET surface area, total pore volume, mesopore volume and micropore volume of the carbon aerogel microspheres with a mean diameter of 45 μm were 903 m 2/g, 0.60 cm3/g, 0.31 cm3/g and 0.27 cm 3/g, respectively. The phenol-adsorption capacity of these carbon aerogel microspheres was 29.3 mg phenol/g adsorbent. © 2013 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.
Some of the metrics are blocked by your
consent settings
The estimation of cell density in isotropic microcellular polymeric foams using the critical bubble lattice
(2011-03-01)
Buahom, Piyapong
;
Areerat, Surat
In this study, models for estimating the cell density of isotropic polymeric foams using the surface cell density were developed. The basic morphological unit cell for these models is a gas-filled pentagonal dodecahedral cell cavity. The critical bubble lattice model was introduced to associate the packing structure of the pentagonal dodecahedral cells with a face-centered cubic (FCC) packing structure, and the cell density was estimated. This model was then used to investigate the effect of nonperfect cell cross-sections as found in the micrographs of cell densities of foams. Two cases were examined: first, the ideal case of a perfect cross-section, and second, the actual case of a nonperfect cross-section. The plots of cell density versus surface cell density from recently published data show the effect of a nonperfect cross-section on the estimation of cell density within an FCC lattice with perfect and nonperfect cell cross-sections. The percentage average absolute deviation (AAD) showed that the nonperfect cell cross-sectional model reliably predicts the cell density of isotropic low-density foam with an AAD of 39.2%. The perfect cell cross-sectional model reliably predicts the cell density of isotropic high-density foam with an AAD of 57.2%. These new models are more reliable than the conventional model, which give AADs 59.4% for low-density foams and 62.4% for high-density foams. Furthermore, the isotropic foam index was introduced as a parameter to indicate the isotropic foam behavior. © The Author(s) 2010.

KMITL

Browse

Filters

Settings

Sort By

Results per page

Search Results