Advanced Materials Research Vol. 1133

Abstract: The effect of heat on the quality of spray dried Tongkat Ali extract was investigated at three different air inlet temperatures (100°C, 180°C and 2200C). Response surface methodology employing the Box-Behnken Design was employed to hunt for the optimum operating conditions at these temperatures. Good retentions of eurycomanone, total polysaccharides and glycosaponins were exhibited during the spray drying process. However, protein was found to be susceptible to thermal degradation during the spray drying process. Use of high air inlet temperatures (i.e. 1800C and 2200C) in spray drying led to greater process yield, lower moisture contents, produced non-sticky particles, and resulted in good powder size distribution of Tongkat Ali extract compared to spray drying at 1000C.

Abstract: This paper presents a significant finding where a capillary force is observed for a gas hydrate growth under a 24-hours shut-in condition (static fluid) using a newly designed apparatus comprising six units of identical rocking cells within isochoric conditions. The gas hydrate growth (static condition) is compared to a gas hydrate formation under a rocking condition. Crystal growth with a simulated natural gas mixture at various time intervals is noted. The visual observations of nucleation and growth at a wetted surface are described. The obtained visual results suggest that capillary forces provide continuous mass-transfer of water towards gas hydrate growth, even within shut-in conditions.

Abstract: This paper has reviewed the failure criteria that had been applied in the wellbore studies. Rock failure studies had applied in the wellbore and reservoir to establish the stability, which is a major problem in oil and gas wells. There problems are both in injection wells and production wells. In injection wells, fracturing is a problem and in production wells, sand production affects the oil flow rate. The stress state of the well determines the stability of the well using the failure criteria.Different failure criteria and their applications had been studied. The theory of the failure has expressed; then applied criteria, formulation and modification of different criteria is expressed for different wellbore studies. And finally the important aspects and differences in wellbore failure rather than the rock surface failure has been discussed.

Abstract: The leaching process of Malaysian low grade manganese ore (LGMO) using bamboo sawdust (BSD) as reducing agent in acidic medium (H₂SO₄) and the dissolution kinetics of this ore was investigated. Acid concentration, reaction temperature, and BSD loading were chosen as experimental parameters through application of response surface methodology (RSM). For analysis of the kinetic data in this study, the SCM with surface chemical reaction and diffusion through product layer, the mixed control modelled and also new variant SCM were evaluated. The reaction kinetics of this leaching process was determined, and it is observed that it fits the model of 1-23X-(1-X)23=kt with activation energy of 69.3kJ/mol. The reaction rate for LGMO leaching using BSD was found to be diffusion through product layer.

Abstract: —Foam stability and mobility reduction are the key parameters for foam assisted enhanced oil recovery. The harsh conditions such as high temperature, pressure and salinity present in an oil reservoir tend to destabilise the foam leading to poor sweep efficiency. Screening for the best performing foaming recipes has been performed to ascertain foam stability in the presence and absence of oil. Static foam test has been performed in order to study the foam stability and foam oil interactions at 90°C. Two anionic surfactants, alpha olefin sulphonate (AOS_14-16) and methyl ester sulphonate (MES_16-18) were mixed with betaine (foam booster) in different proportions to design the formulations. In addition to the ternary formulations, binary formulation involving surfactant and betaine were also evaluated for foam stability. For the study of oil effects on foaming performance of surfactant formulation, n-decane, diesel and Dulang crude oil are used. The recipes were evaluated by static foam tests to note the foam height and endurance time. It was found that the anionic surfactant played a major role in foam stability and the betaine was found less significant. However, the betaine alone was found effective for foaming and was poor for endurance time. While in mixture, the surfactant and betaine were found to interact strongly and a profound synergistic effect was noted. During oil interaction studies, the alkane type oils of low molecular weight become solubilised with surfactant molecule forming an emulsion and hence decimate the foam stability. However, higher alkanes with molecular chain more than ten carbon atoms (decane) stabilised the foam because of low solubilisation efficiency between surfactant and oil to form emulsions. The obtained results of the designed experiment have been analysed and discussed in detail to understand the contribution of individual component as well as their interactions with each other in order to stabilize foams.Keywords—Static Foam, Foam-Oil interactions, AOS, MES, Enhanced Oil Recovery

Abstract: Besides other application of clathrate hydrates, hydrate-based CO₂ capture and storage are potentially important where additives are commonly used to speed up the hydrate formation processes in order to gain on scientific, technological and economic interest. In this work combination of additives such as tetrahydrofuran and sodium dodecyl sulphate (THF/SDS) on mixed gas hydrate formation and dissociation condition have been investigated using a graphical method. The measurements were carried out at temperature and pressure range of (265 to 300) K and (1 to 5) MPa. The presence of additive 3 mol % THF has drastically increased in the hydrate stability region while with the combination of SDS + THF lower the hydrate equilibrium temperature marginally.

Abstract: Cellulose microfibers (CMF) were produced by utilizing recycled newspaper paper (RNP) as starting material. This approach is considered as green since recycling newspaper leads to the environment preservation and also cost-effective. The effect on the structural properties of cellulose produced at different stage of pretreatment were investigated by using Fourier transform infrared (FTIR), Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Thermal gravimetric analysis (TGA). The FTIR and SEM demonstrate that the hemicellulose and lignin was successfully removed from the structure of the CMF. XRD and TGA results revealed that the different step of pretreatment was increased the crystallinity and thermal stability of CMF increased gradually. The improvement in CMF crystallinity has improved its thermal properties which is important in the field of reinforcement material.

Abstract: In this work, synthesis of ZIF-8 membranes via in situ and secondary seeded growth methods was conducted at the preliminary stage. Synthesis durations were varied at 4 h and 36 h using in situ growth method. For secondary growth, the seeding procedure was applied through rubbing and dip-coating of the seeds on the support. The resultant membranes were characterized using X-ray diffraction (XRD) and scanning electron microscope (SEM). Subsequently, the defects of the resultant membranes were determined using nitrogen gas permeation test. The results showed that, ZIF-8 membrane synthesized using in situ growth method for 4 h exhibited highest crystallinity and lower defects with the nitrogen gas permeance of 5.09 × 10^-7 mol/m²·s·Pa. Besides, in situ growth method has shown its potential in synthesizing high quality ZIF-8 membrane through an easy and faster route.

Abstract: In Malaysia, due to abundance of oil palm waste, it is a good candidate to be used as a feedstock for syngas and hydrogen production. Biomass steam gasification is one of the promising methods for syngas production. This work focuses on the steam gasification with in-situ CO₂ capture using CaO as absorbent materials for hydrogen production from palm oil empty fruit bunch (EFB). Three parameters (temperature, steam/biomass ratio and sorbent/biomass ratio) has been studied on the lower heating value (LHV) and higher heating value (HHV) of product gas. The results shows that the current study gives higher value of LHV at lower temperature of 823K. The higher value of LHV is obtained due to the lower concentration of CO₂ caused by using CaO as sorbent material. Furthermore, CaO materials enhanced the concentration of concentration of the CO, H₂ and CH₄ in the product gas. The results are also compared against published data as well.

Abstract: Volumetric characterstics of multiple electrolytic solutions in a wide range of solute concentrations and solutions temperatutre are of fundamental importance for the understanding of numerous physicochemical processes occurring in various brances of the chemical industry as well as in the natural envirnoment. In a view of importance of NaCl as primary salts in seawater and most of other natural water, accurate thermophysical data is crucial for understanding industrial and natural processes [1]. Ionic interaction plays an important role in chemical reactions in solutions [2]. In fact, the effect of the addition of salts in aquous solutions of ILs is very complex, primarily because a large number of different types of intermolecular interactions come into play between the ion and water, ion and IL, and IL and water. From a thermodynamic perspective, the solvation of ionic species in the ILs is much more favored than in conventional solvents. This is one of the key advantages of using ILs in separations involving ionic species.