KMITL

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

Browse

Search Results

Now showing 1 - 5 of 5

Some of the metrics are blocked by your
consent settings
Mineral filler characteristics and non-Newtonian viscosity of asphalt mastic at high temperature: A response surface methodology approach
(2026-12-01)
Chamwon, Suwaphit
;
Hutabarat, Multazam
;
Chaturabong, Preeda
Asphalt mastic—composed of asphalt binder and mineral filler—strongly governs the high-temperature viscosity of asphalt concrete during mixing and compaction. This study investigates the effects of four mineral fillers (granite, limestone, shale, and pumice) on the viscosity and flow behavior of asphalt mastics at elevated temperatures (130–170 °C). Comprehensive filler characterization was performed, encompassing morphological analysis by scanning electron microscopy (SEM), physical property evaluation (particle density, specific surface area, and Rigden voids), hydrophilic coefficient determination, particle size distribution by laser diffraction, and mineralogical identification by X-ray diffraction (XRD). Response surface methodology (RSM) with a central composite design (CCD) was employed to model the combined effects of temperature (130–170 °C), filler content (5–30% by volume), and rotational speed (10–30 RPM) on apparent viscosity measured by a Brookfield rotational viscometer. The non-Newtonian index, derived from the power-law (Ostwald–de Waele) model, was used to classify flow behavior. Results demonstrate that temperature and filler content are the dominant parameters governing viscosity, while rotational speed controls the degree of non-Newtonian behavior in a filler-dependent manner. A critical transition from quasi-Newtonian to pronounced non-Newtonian flow was identified at 15–20% filler content by volume, coinciding with a sharp increase in the effective solid volume fraction that approaches the colloidal packing threshold (φ* ≈ 32–34%). Pumice exhibited the strongest shear-thickening (n up to 1.22) while granite showed consistent shear-thinning (n ≈ 0.88–0.94), with limestone and shale showing mixed behavior. Pumice and shale produced the strongest viscosity stiffening, consistent with greater binder immobilization due to their higher Rigden voids. AASHTO T316 workability analysis indicates that under base-binder conditions, the maximum filler content within practical mixing limits at 160 °C is approximately 30% for granite and limestone but only ∼22% for pumice. The validated quadratic RSM models (R² = 0.84–0.96) provide a practical framework for optimizing filler selection and processing temperatures in asphalt mixture design.
Some of the metrics are blocked by your
consent settings
Enhancing biodiesel yield and purification with a recently developed centrifuge machine: A response surface methodology approach
(2024-04-15)
Limmun, Warunee
;
Chungcharoen, Thatchapol
;
Rattanamechaiskul, Chaiwat
;
Phetpan, Kittisak
;
Limmun, Wanida
Biodiesel production processes, such as gravity settling, have limitations in terms of biodiesel yield, purification efficiency, operating time in the separation process, and more extensive equipment. Therefore, this study has focused on using a recently developed centrifuge machine for biodiesel separation to address these challenges due to its compact design, high efficiency, and simplicity. Additionally, this study aimed to optimize the separation efficiency of glycerol from biodiesel using a centrifuge machine, employing response surface methodology (RSM) with central composite design (CCD). The optimum conditions for separating glycerol from biodiesel via centrifuge machine are a rotation speed of 1800 rpm, a mixture flow rate of 192.25 ml/min, and a temperature of 55 °C, respectively. In optimum conditions, 94.52% separation efficiency was achieved. Biodiesel production can be improved, leading to higher yields and greater purity. The utilization of RSM proved valuable in determining the optimum conditions for separation. Furthermore, the machine successfully separated the biodiesel to meet ASTM D6751 and EN 14,214 standards. The results highlight the potential of the centrifuge machine for efficient and reliable biodiesel production, contributing to the advancement of the biodiesel industry.
Some of the metrics are blocked by your
consent settings
Optimization of hot-water extraction of dried yacon herbal tea leaves: Enhanced antioxidant activities and total phenolic content by response surface methodology
(2019-01-01)
Ueda, Yuto
;
Apiphuwasukcharoen, Nippitch
;
Tsutsumi, Shuhei
;
Matsuda, Yasushi
;
Areekul, Varipat
Yacon (Smallanthus sonchifolius) is an herbal plant and its root has been historically consumed as a sweet vegetable in the Andes. With the research goal of establishing yacon leaves, grown in Japan, as a foodstuff with health benefits, we previously reported the antioxidant effects of yacon tea leaves using concentrated extracts. In this study, we determined the optimum conditions for regular hot-water extraction of yacon tea leaves, intended for normal consumption, aiming for higher activity in several antioxidant assays and total phenolic content (TPC). Response surface methodology was used to optimize the extraction by central composite design. Extraction temperature (ranging from 75.0 to 96.0 ℃) and time (from 2.00 to 5.50 min) were set as the two independent variables. Based on a composite desirability value of 0.863, the hot-water extraction of yacon tea at 89.3 ℃ for 2.50 min was found to be the optimized condition providing higher antioxidant activity and TPC.
Some of the metrics are blocked by your
consent settings
Optimization of microbial collagenolytic enzyme production by Bacillus subtilis subsp. Subtilis S13 using Plackett-Burman and response surface methodology
(2019-01-01)
Khamson, A.
;
Sumpavapol, P.
;
Tangwatcharin, P.
;
Sorapukdee, S.
Bacillus subtilis subsp. subtilis S13, a new isolate from soil is found to be the collagenase producing bacteria. The results showed that gelatin concentration, initial pH, and incubation time were accounted for significant factors from PB design and then applied for a central composite design (CCD) under response surface methodology (RSM) for optimization of significant factors were performed. The optimum parameters for the enhancing gelatinase production through CCD and response surface methodology were 19 g/l of pork gelatin, initial pH 6.16 for culture medium, and 59 h of incubation time, which provided the predicted maximum collatinolytic activity of 65.36 U/ml. This condition allowed approximately increasing 4-folds as compared to un-optimized condition (15 U/ml). The obtained optimal activity of this enzyme might be expressed the potential collagenase for several applications including meat tenderizing enzyme.
Some of the metrics are blocked by your
consent settings
Simulation of V2O5/TiO2 catalyst activity by central composite design for optimal operating conditions and catalyst life in phthalic anhydride production
(2015-05-25)
Lothongkum, Anchaleeporn Waritswat
;
Sethapokin, Pinthep
;
Ouraipryvan, Piya
A simple central composite design was applied to estimate the activity of V<inf>2</inf>O<inf>5</inf>/TiO<inf>2</inf> catalyst and catalyst life in phthalic anhydride production. Using 1-3 years of simulation data, it was found that the temperature profiles along the catalyst bed and the outlet flow rates of phthalic anhydride and maleic anhydride (main by-product) were less than 8% deviation compared with the plant data. In comparing the simulated optimal conditions to the normal operating conditions, the phthalic anhydride production increased by 1,600ton with the inlet o-xylene-air ratio (w/w) and the coolant temperature, while maleic anhydride decreased by approximately 340ton.

KMITL

Browse

Filters

Settings

Sort By

Results per page

Search Results