Materials Science Forum Vol. 998

Abstract: Watermelon or Citrullus lanatus is a common fruit for daily consumption in Indonesia. The anthocyanin and flavonoid in watermelon rind serve a good antioxidant effect for protecting human body health from free radical damage. The objective of the present work is to observe and calculate the amount of anthocyanin and flavonoid in watermelon rind with two different colourscolours of fruit flesh harvested in Indonesia, that are red and yellow. Total polyphenol content was also observed in this work. Total anthocyanin content was derived in this study was (0.02±0.000) up to (0.05±0.000) mg/L and the lowest and highest value were found in MTK and MK, respectively. For total flavonoid content, the value in a range between (0.71±0.000) mg/L and (1.63±0.002) mg/L. The polyphenol value was between (0.38±0.002) mg/mL and (0.57±0.001) mg/mL. The lowest and highest values of flavonoid and polyphenol were found in MTK and KK. This work provided information on three compounds that will be useful.

Abstract: The cinnamon essential oil has antibacterial characteristic and sensitive to light and oxygen [1]. Due to its benefits from cinnamaldehyde, this compound has already used for antibacterial agent injected in polymer film [2]. Films are usually made from natural polymers as their main materials such as pectin. This research observed the influence of calcium chloride addition (0; 0.01; 0.02; and 0.03 g/mL solution) in the physical characteristics of pectin based edible films using the immersion method. The results indicated that calcium chloride content did not effect significantly. On the other hand, increasing calcium chloride content increased the water sorption of phosphate buffer saline solution and 0.03 g/mL of calcium chloride offered the lowest water sorption. Addition of cinnamaldehyde affected the surface morphology of the film and gave the crystal structure on the surface.

Abstract: Microwave-assisted synthesis of polyglycerolsebacate (PGS) - polycaprolactone (PCL) with nanoclay composite films were fabricated in this study. PGS produced via microwave irradiation technique was blended withorgano-modified montmorillonite (O-MMT) and PCL, and cast using thermally induced phase separation technique (TIPS) to produce nanocomposite films. The fabricated films underwent different qualitative characterization to identify its morphology, porosity,wettabilityandmechanical strength. FTIR results showed changes in the band peaks signifying the interaction between PCL, O-MMT and PGS. SEM images of the films displayed filamentous and non-uniform pores present on the films, which became more visible upon the addition of O-MMT and PGS.Also, the films showed improved tensile strength and elongation upon addition of PGS, but on an optimum O-MMT amount. Furthermore, the pore size of films increased upon addition of PGS, which confirmed the effect of its hydrophilic in nature. Thiswas correlated to the enhanced wettability of the films produced and the formation of asymmetric surface structure.

Abstract: Capsaicin (CAP) is a pungent alkaloid of chili peppers that is obtained from chili peppers that has a variety of pharmacological activities and can be used in various areas, such as functional foods, nutritional supplements and medical nutrition. Capsaicin has important anticancer, antioxidant and anti-inflammatory properties that allow to be applied as treatment for several diseases. However, its lack of water solubility, as well as its poor oral bioavailability in biological systems, show limiting factors for its successful application. Recently, the formulation of capsaicin for food and pharmaceutical use is limited. Therefore, the present study emphasized on preparation of capsaicin-loaded chitosan nanoparticles (CAP-CSNPs) and design and optimization of the formulation using Box-Behnken experimental design (BBD) and response surface methodology (RSM). The capsaicin-loaded chitosan nanoparticles were prepared by o/w emulsification and ionotropic gelification. The optimized formulation of capsaicin-loaded chitosan nanoparticles had a chitosan concentration of 0.11 (%w/v), a Tween 80^® concentration of 1.55 (%w/v) and a CAP concentration of 1 mg/mL and that it should be stored at 4°C. Box-Behnken experimental design and response surface methodology was found to be a powerful technique for design and optimization of the preparation of capsaicin-loaded chitosan nanoparticles using limited number of experimental runs. Our study demonstrated that capsaicin-loaded chitosan nanoparticles can be potentially utilized as dietary supplements, nutraceuticals and functional foods.

Abstract: We used Brownian Dynamic simulation to study structural and dynamic properties of bi-disperse colloidal suspensions. The size ratio of large to small particles in the bi-disperse colloidal suspension is set at 5:1 and 10:1. We studied the interaction of aggregates (clusters) formed through DLVO (Derjaguin, Landau, Verwey and Overbeek) and soft sphere interactions in a bi-disperse suspension. The dynamic properties of bi-disperse is correlated by varying the size ratio of bi-disperse particles, it is found that the mobility is decreased at size ratio of large to small particles is 5:1. This is despite the percolating particle gels formation was disrupted by larger particles at higher size ratio.

Abstract: Thanks to its porous structure the autoclaved aerated concrete has excellent thermal insulation properties. The production of this building material is carried out in two main steps. At first calcium hydroxide reacts with aluminum powder. This reaction releases hydrogen which creates the porous structure. Secondly lime reacts with siliceous components under hydrothermal conditions. This reaction forms crystalline calcium hydrosilicates which represent a binder component in the material. Focus of this paper is to study the degree of crystallization of calcium hydrosilicates depending on the quantity and fineness of the admixture of the waste foundry sand. This material was tested in three different values of specific surface. The influence of granularity of the waste foundry sand on the microstructure and physical-mechanical properties of the autoclaved aerated concrete was monitored. At the same time, the influence primary filler substitution by foundry sand was also observed. The substitution was realized in amounts of 10%, 30% and 50%. As the final step the influence of the waste foundry sand admixture on the autoclaved aerated concrete porous structure was evaluated. The microstructure was analyzed by X-ray diffraction. Obtained values show that admixture of waste foundry sand has positive effect on the crystallisation of calcium hydosilicate phases. Substitution of primary filler by waste foundry sand is possible up to 50%. With a higher amount of substitution, the higher values of compressive strength of autoclaved aerated concrete were monitored.

Abstract: This research investigates the effects of aggregate packing degree on the strength of Reactive Powder Concrete (RPC) mixtures on the basis of the Toufar model. To optimize the packing degree of sand for strength development of RPC, various sand blends with the combination of different fraction size were used. In addition, 10 different blends that showed best packing degree were chosen to investigate the compressive strength of RPC. It was found that experimental verification results conform to Toufar model calculations. The test result shows that packing degree had a significant effect on the strength of RPC: Mixtures with higher packing degree can achieve higher compressive strength. Furthermore, Results indicate the Toufar model can predict packing degree of aggregate blends.

Abstract: Autoclaved aerated concrete (AAC) is, mainly in Europe, widely used construction material. It has an optimal combination of bulk density, strength and thermal conductivity coefficient for load-bearing and non-load-bearing structures of civil facilities. The production technology is based on a mixture of ground silica sand, lime, cement, gypsum, aluminium powder and additives. The grinding of sand is most often carried out in a wet way, and the sand sludge is consequently used in production technology. The aim of the experiment was verification of the effect of partial replacement of sand with the alternative raw materials in sand sludge on the rheology of the mixture. This parameter determinates how the modified mixtures affect the sludge pumpability. As a reference the consistency of the sand sludge of the normal production density of 1.65 g/cm³ was compared to the sand sludges of different density (1.60, 1.70 and 1.75 g/cm³) and with a fresh aerated concrete (FAC) mixture of 1.60 g/cm³. Then the sludges were modified by 30 % of alternative raw materials (recycled glass, coal slag, FBC ash, FBC bottom ash) as the partial weight replacement for sand. This partial replacement resulted in water/solids ratio adjustment which recommended value is 0.47 for recycled glass and coal slag, 0.59 for fluidized bed combustion (FBC) bottom ash and for FBC fly ash it is 0.70.

Abstract: The conventional embankment has disadvantages in terms of its weight; it has an implication for the level of deformation that will occur on the subgrade layer. This study was conducted dealing with the design of geocomposite material compositions based on their mechanic characteristics. The lightweight geocomposit material (LWGM) was constructed by composing soil with expanded polystyrene (EPS) with by-product of buton asphalt as the binder agent (WBA). Unconfined Compression Test (UCT) and California Bearing Ratio (CBR) were examined to figure out the mechanical behavior of LWGM. The percentages of WBA used on specimens were 3%, 5%, 7% and 9%, while those of EPS were 0.15% and 0.30%, based on weight of soils dry density. Furthermore, to understand the curing period effect, all the specimens were cured and tested within 7 days and 28 days. The results showed that the LWGM could reduce the embankment densities from 20% to 35%, compared to conventional embankment. The compressive strength and CBR values presented the same tendency, so that, based on correlation of UCS and CBR value, the LWGM compositions that are appropriate for road foundation criteria as subbase courses are 3.2% to 7% for the WBA and 0,15% - 0,30% for the EPS.

Abstract: Portland cement (OPC) is one of the primary contributors accounted for climate change as a massive amount of Carbon dioxide is emitted to the atmosphere during its production processes. Geopolymer cement (GP), a green construction material, is therefore promoted to be an alternative cementitious binder to replace the consumption of that OPC. GP can be synthesized by mixing pozzolanic wastes (e.g., fly ash or slag) with alkaline solutions (e.g., NaOH and Na2SiO3). The mechanical properties of the geopolymer have been confirmed to be similar to or even better than OPC in the same testing conditions. However, the researches on GP have been mostly carrying out in just a laboratory scale, thus, the Laboratory grade of alkaline activators was commonly used. To make GP more realistic in practical works, the Industrial grade of alkaline activators was hence introduced. The results show that the usage of Industrial grade activators not only provides excellent mechanical properties to GP but also reduces its unit price to less than 20 percent of the conventional GP (GP with Laboratory-grade activator). By this approach, the confidence of expanding this green construction material, from Laboratory scale to In-field applications, is considerably increased.