Rajamangala University of Technology (Thai: มหาวิทยาลัยเทคโนโลยีราชมงคล), (RMUT), is one of the university systems in Thailand. It has nine universities providing undergraduate and graduate level education. It was elevated to university status in 2005. Before that it was known as Rajamangala Institute of Technology (สถาบันเทคโนโลยีราชมงคล).In September 2016, Prime Minister Prayut Chan-o-cha invoked Section 44 of the interim charter allowing him to form a special panel to take over administration of Rajamangala University of Technology Tawan-ok as it was judged to be incapable of administering itself.
This study investigated cellular lightweight high-calcium fly ash geopolymer concrete incorporating basalt fibers and cured at ambient temperature. Foam was incorporated at 0–6% by weight, while basalt fiber was added at 0–6% by weight of fly ash. The compressive strength, density, water absorption, porosity, thermal conductivity, and sound absorption were evaluated. The results demonstrated that foam content played a dominant role in reducing density and thermal conductivity, whereas an appropriate basalt fiber content improved the mechanical performance of the cellular lightweight geopolymer concrete. The mixture containing 4% basalt fiber and 3% foam exhibited the optimum performance for structural lightweight concrete applications, achieving a compressive strength of 38.3 MPa at a density of 1691 kg/m³. For masonry applications, increasing the foam content to 6% produced a substantially lower density of 1119 kg/m³ while maintaining a compressive strength of 6.32 MPa. Furthermore, the Strength-Density-Cost-Carbon Performance Index (SDCC-PI), based on strength–density efficiency, material cost, and GHG emissions with equal weighting after ASTM-based screening, was used to identify suitable mixtures for different applications. The SDCC-PI results confirmed that the optimum mixture depends on the intended application and the required balance among mechanical, physical, economic, and environmental performance. Overall, the developed cellular lightweight geopolymer concrete demonstrates potential as an ambient-cured lightweight construction material with favorable mechanical, thermal, and acoustic properties.
This study proposes a numerical investigation of enhanced thermal performance in a circular tube equipped with periodically arranged, inclined delta wings (DWs) mounted directly on the inner tube walls. The turbulent airflow is evaluated for Reynolds numbers (Re) between 3000 and 21,000 utilizing the finite volume approach along with the Realizable k-epsilon turbulent model. The analysis is performed in two different phases: solid delta wings (DW) and punched delta wings (PDW). In the solid DW phase, the angle of attack (alpha) is kept constant at 45 degrees, and geometric parameters include a set of four base/chord ratios (BR = 0.4 to 0.7) and four pitch ratios (PR = 0.5 to 1.5). The forward delta wing (F-DW) constantly outperforms the backward delta wing (B-DW) in terms of heat transmission enhancement, as indicated by comparative analysis of the DWs. In contrast to a smooth tube, the F-DW generates streamwise vortices that greatly boost fluid interaction and heat transmission, but at the sacrifice of rising pressure loss. The greatest Nusselt number (Nu) and friction factor (f) are realized with the F-DW at the narrowest pitch ratio (PR = 0.5) and its highest base ratio (BR = 0.7). Under baseline operating parameters of PR = 0.75 and Re = 3,000, the largest thermal enhancement factor (TEF) values of 2.79, 2.82, and 2.76 are achieved, with corresponding Nu ratios of 7.69, 8.79, and 10.34 for BR = 0.4, 0.5, and 0.6, respectively. In the second phase, a novel perforation approach is employed on the optimal F-DW (BR = 0.5, PR = 0.75) to establish a forward punched delta wing (F-PDW). This cutting-edge F-PDW attains a maximum TEF of 3.01 alongside a Nu ratio of 9.24. The findings show that, as contrasted to solid DWs and smooth tubes, the FPDW greatly increases overall TEF, indicating its great potential for efficient, smaller heat exchanger applications.
This study addressed the thermal degradation of bioactives during industrial processing by developing and characterising hydrogel beads from Kaew Kamin mango pulp as a clean-label strategy to enhance stability and modify texture. Beads were formulated using a sodium alginate matrix cross-linked with calcium lactate (0.5–1.5 g/100 g) and stabilised with gum Arabic or guar gum (0.2 or 0.4 g/100 g). A factorial experimental design was used to assess the effects of cross-linker concentration, gum type, pump speed, and gelation time on bead properties. The optimised formulation, incorporating 0.4 g gum Arabic/100 g and 1.5 g calcium lactate/100 g, produced at a pump speed of 2 cm/s with a 10 min gelation time, yielded beads with high firmness (33.98 N), low swelling (< 20
The development of paper materials with advanced functionalities offers new opportunities for applications beyond traditional uses. In this study, a fluorine-free and environmentally friendly superhydrophobic coating was fabricated via a simple spray coating method. VTMS-modified SiO2 nanoparticles (VTMS/SiO2) were applied to atmospheric plasma-treated paper using polydimethylsiloxane (PDMS) and KH550 as crosslinking and coupling agents, respectively. The chemical functionalities of the surface and the morphology of the coated samples were characterized by FTIR and SEM. Among the different formulations, the optimum condition, i.e., 15 s plasma treatment followed by coating with 7.5VTMS/SiO2/0.75KH550, resulted in excellent superhydrophobicity with a water contact angle (WCA) of 160.4 ± 0.5° and a sliding angle (WSA) of 4.5 ± 1.1°. In addition, the coating exhibited excellent mechanical resistance and retained its properties after 20 Taber abrasion cycles. Chemical stability under acidic and alkaline conditions was also maintained. Compared to coatings without plasma treatment, the plasma-enhanced surface exhibited significantly improved adhesion and robustness. These results illustrate a scalable, fluorine-free strategy for producing durable, multifunctional paper surfaces suitable for advanced packaging and protective applications.
This research aims to provide finite element model to predict the linear and nonlinear responses of sandwich curved beams composed of FG-GPLRC faces and FG-TPMS cores under multiple moving forces. Sinusoidal shear deformable theory, coupled with nonlinear strain components, is used to derive the nonlinear equations of motion for describing their dynamic behavior. The effective material properties of the faces are estimated using a micromechanical model of Halpin-Tsai, while the core properties are obtained from the variation of relative density in different configurations of TPMS unit cell. The solution is obtained iteratively using the Newmark time integration method and the Newton-Raphson method. Several key factors, including material properties, material compositions, GPL content, coefficient of relative density, core-to-face thickness ratio, angle, slenderness ratio, velocity, and number of moving forces, significantly influence the responses of the beams. These factors are examined to better understand the nonlinear behavior of the beams. By considering geometrical nonlinearity, it is found that the difference between the maximum linear and nonlinear responses exceeds 10 %. In addition, the results show that adding GPLs improves the beam's ability to withstand deformation under moving forces and increases the critical velocity. These findings highlight the importance of optimizing both material composition and beam’s geometries to achieve the desired structural performance.
