New batch and continuous systems for converting hydrogen from water hyacinth

Water hyacinth was the chosen alternative biomass for H₂ production in this study. A batch and a continuous pilot plant systems are proposed. A batch system of 500?ml capacity was developed first for finding an appropriate biomass ratio which was found to be 2.5%wt. Results from the batch system was used to construct a kinetic model of water hyacinth hydrolysis. The same biomass and water ratio was used in the continuous system. Besides water hyacinth, glucose and cellulose?+?lignin biomasses were tested. During processing, temperature, pressure, and electric consumption of the system were recorded. The quality and quantity of gas products were analyzed by gas chromatography (GC). The water hyacinth biomass attained the highest rate of H₂ production (providing energy of 11.43?kWh/mole of glucose). Comparing the batch and continuous pilot systems, the continuous system achieved 2.7 times more H₂ mole% than the batch system did.     

Extraction of protein from skim natural rubber latex using PEG as a surfactant via low speed centrifugation and continuous flow

Protein extractions from skim natural rubber latex using 3 %w/v polyethylene glycol (PEG6000) via both low speed centrifugation and continuous flow were investigated. In centrifugal extraction, when the speed was 1000 rpm, the extractable protein (EP) content in serum increased with processing time from 5 to 30 min and when the time was fixed at 5 min, EP content increased with centrifugal speed. In addition, further washing deproteinized chips with 2 %w/v SDS solution could remove proteins with efficiencies corresponding to the efficiencies of protein removals in latex phase, implying the role of PEG in protein reduction in both steps. In continuous flow extraction, EP content increased with increasing Reynolds number or increasing mean residence time of the flow to a maximum and then dropped. The efficiencies of the centrifugal extraction and continuous flow extraction were 55.2 and 33.7%, respectively. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39900.     

Kinetics and Equilibrium Modeling of Sterol Adsorption on Styrene‐Divinylbenzene Cation‐Exchange Resins

The potential of recovering phytosterols from fatty acid methyl esters by an adsorption‐desorption process is demonstrated using a strong‐acid ion‐exchange styrene‐divinylbenzene resin (SA‐R) as an adsorbent and ethanol as a desorbent. Since the operating cost of the overall process significantly depends on the efficiency of SA‐R in the adsorption step, the behavior of SA‐R in sterol adsorption is investigated in detail using a model solution of stigmasterol in n‐heptane. The results indicate that stigmasterol was associatively and exothermically adsorbed on SA‐R. Based on the experimental results, a simple pseudo‐second‐order model and a modified Langmuir isotherm with their parameters, which well predicted kinetics and adsorption capacity of SA‐R, are proposed.     

Amplification of Periodic Temperature Disturbances in a Packed‐Bed Reactor: CO Oxidation over a CuO/Al2O3 Catalyst

Amplification of periodic variations of input temperature in a product‐inhibited reaction — CO oxidation over CuO‐γ‐Al₂O₃ — was investigated experimentally in an insulated packed‐bed reactor. At steady state the temperature profile was elongated compared with that of a reactant‐inhibited CO oxidation over Pt/Al₂O₃, studied elsewhere. Under periodic operation, amplitudes of the resulting travelling temperature waves, monitored downstream from the reaction front, were amplified to a greater extent than those in the reactant‐inhibited CO oxidation over Pt/Al₂O₃. The magnitude of the amplification depended on the perturbation frequency and showed resonance behaviour. The magnitude decreased monotonically with increasing perturbation amplitude.     

QM methods in structure based design: utility in probing protein-ligand interactions

Small changes in ligand structure can lead to large unexpected changes in activity yet it is often not possible to rationalize these effects using empirical modeling techniques, suggesting more effective methods are required. In this study we investigate the use of high level QM methods to study the interactions found within protein-ligand complexes as improved understanding of these could help in the design of new, more active molecules. We study aspects of ligand binding in a set of protein ligand complexes containing ligand efficient, fragment-like inhibitors as these structures are often challenging to determine experimentally. To assess the reliability of our theoretical models we compare the MP2/6-31+G** QM results to the original X-ray coordinates and to QM/MM B3LYP/6-31G*//UFF results which we have previously reported. We also contrast these results with data obtained from an analysis of the distribution of comparable interactions found in (a) high resolution kinase complexes (≤ 1.8?) from the PDB and (b) more generic, small molecule crystal structures from the CSD.     

Esterification of palm fatty acid distillate (PFAD) in supercritical methanol: Effect of hydrolysis on reaction reactivity

This study demonstrated the potential use of local palm fatty acid distillate (PFAD) as alternative feedstock for fatty acid methyl esters (FAMEs) production and the possibility to replace the conventional acid-catalyzed esterification process (with H₂SO₄), which was industrially proven to suffer by several corrosion and environmental problems, with non-catalytic process in supercritical methanol. At 300 °C with the PFAD to methanol molar ratio of 1:6 and the reaction time of 30 min, the esterification of PFAD in supercritical methanol gave FAMEs production yield of 95%. Compared with transesterification of purified palm oil (PPO) in supercritical methanol, the production of FAMEs reached the maximum yield of only 80% at 300 °C with higher requirement for methanol (1:45 PPO to methanol molar ratio). Compared with the conventional acid-catalyzed esterification of PFAD, only 75% FAMEs yield was obtained in 5 h. The presence of water in the feed (between 0 and 30% v/v) was found to lower the yield of FAMEs production from PFAD significantly. This negative effect was proven to be due to the further hydrolysis of FAMEs, which nevertheless can be minimized when high content of methanol was used.     

Efficacy of chitin-PAA-GTMAC gel in promoting wound healing: animal study

Acrylic grafted chitin (chitin-PAA) was modified with glycidyltrimethylammonium chloride (GTMAC) with the aim of promoting wound healing. The chitin-PAA-GTMAC gels with different GTMAC contents were compared with the original chitin-PAA gel and Intrasite gel for their efficacy in deep wound healing of Wistar rats. Four full-thickness wounds were made on the dorsal skin of rats and then each was treated with 4 materials; chitin-PAA, chitin-PAA-GTMAC(1:4), chitin-PAA-GTMAC(1:10) and Intrasite gel. During 18 days of treatment, the wounds were visually observed and calculated for wound size using image analysis program. Skin wound tissues of sacrificed rats were processed for routine histological observation and immunohistochemistry of proliferating cell nuclear antigen (PCNA). The wounds covered with the chitin derivatives either with or without GTMAC showed a significant reduction in wound size in day 9 in comparison with day 12 for those covered with Intrasite gel. The faster rate and the better pattern of epidermal development observed in histological study as well as the higher dermal cell proliferation (PCNA expression) also demonstrated the better efficiency in wound healing of the chitin derivatives than Intrasite. The earliest epidermal development of the wounds treated with chitin-PAA-GTMAC (1:4) among the tested materials suggested the most promising of this material for the treatment of full-thickness open wound.     

Layer-by-layer deposition of green synthesised silver nanoparticles on polyester air filters and its antimicrobial activity

Silver nanoparticles stabilised with anionic polymeric polyelectrolytes were successfully synthesised by high-energy UV reduction. Three types of polyelectrolytes were used including poly(methacrylic acid) (PMA), poly(acrylic acid) (PAA) and poly(4-styrenesulphonic acid-co-maleic acid) (CoPSS). The formation of the prepared solutions exhibited surface plasmon resonance at the wavelength of 475, 730 and 408 nm by using PMA, PAA and CoPSS as the stabilising agents. UV–visible spectrophotometer, transmission electron microscope (TEM) and zeta potential analyser were employed to characterise the formation of the prepared solutions. The silver nanoparticles stabilised with anionic polyelectrolytes were immobilised on polyester air filters using a layer-by-layer technique. This is the sequential dipping of polyester air filters in a dilute solution of cationic poly(diallyldimethylammonium chloride) and anionic polymeric polyelectrolytes capped silver. The surface topography of the polyester air filters were measured by field emission scanning electron microscope. Results showed that silver nanoparticles had the highest surface coverage on the polyester air filters probably because it is a good bonding candidate and insures strong film growth. The multilayers polyester air filters coated silver nanoparticles were tested against the gram positive pathogen Staphylococcus aureus. The deposition of silver nanoparticles onto the polyester air filters resulted in 92.18%, 84.32% and 71.19% of bacteria removal using PMA, PAA and CoPSS as the stabilising agent.     

Recovery of useful chemicals from oil palm shell-derived oil using zirconia supporting iron oxide catalysts

The possibility for recovering methanol, acetic acid and phenol from oil palm shell-derived oil was investigated. Thermal cracking mainly produced a solid residue and was not a suitable method for recovering these three target chemicals. When zirconia supporting iron based catalyst (Zr/FeOx, Zr-FeOx or Zr-Al-FeOx) was applied, the “others”—unidentified hydrocarbons—were satisfactorily removed without formation of a solid residue while these target compounds were considerably stable over these catalysts. Zr-Al-FeOx showed the highest activity for oxidation of the oil to CO₂. Effect of operating parameters (steam to oil ratio, temperature and time factor) on its performance was further investigated. In order to gain insight into the reaction path, the reaction using model compounds (methanol, acetic acid, acetone, ethyl acetate and phenol) was performed. This paper was presented at the 11th Korea-Japan Symposium on Catatysis held at Seoul, Korea, May 21–24, 2007.     

Fourier Transform Infrared Spectroscopy for Antioxidant Capacity Determination in Colored Glutinous Rice

The determination of total phenolic content and antioxidant capacity of 48 colored rice varieties and two white rice varieties from Thailand by Fourier transform infrared (FT-IR) spectroscopy (400–4,000 cm^?1) was performed to explore the possibility of using FT-IR as an effective alternative technique for such determination. The peak at 1,635 cm^?1 resulted from the ring C-C stretch of phenyl was clearly observed. The levels of phenolic content in rice samples as indicated with infrared spectrum were consistent with the results from chemical assays. Dark glutinous rice had the highest level of antioxidant capacity and phytochemicals followed by red rice, brown rice, and white rice. The hierarchical cluster analysis based on selected principal components from principal component analysis model was performed to produce dendrograms which discriminated rice varieties according to their color well. The partial least squares regression models were constructed, and validated models were used to predict total antioxidant capacity and total phenolic content of the rice varieties. Satisfactory precision of prediction was achieved. With technical advantages that FT-IR offers especially when large number of samples are to be analyzed, FT-IR spectral features with chemometrics are suggested to be applicable for quantification and prediction of antioxidant capacity and phenolic compound content of colored rice.