Combustion characteristics of biomass in SouthEast Asia

Gas emission during combustion of mixed tropical wood, bamboo, oil palm trunk, acacia, and rubber wood have been investigated by using TG–MS in presence of oxygen as well as FTIR. The weight decreasing profiles and the gas formation rates of oil palm trunk was significantly different among the samples although their elemental composition was almost the same from biomass samples. It was found that H₂O is the main product formed for all samples. The evolving rates of the gaseous products during the combustion and infrared spectrums such as CO, H₂O, CO₂, CH₄ and COOH⁺ were found. The DTG curves spectrums for biomass present four overlapping peaks.     

Effects of rf power on the structural properties of carbon nitride thin films prepared by plasma enhanced chemical vapour deposition

Carbon nitride (CN_x) thin films were deposited by radio frequency plasma enhanced chemical vapour deposition (rf PECVD) technique from a gas mixture of methane (CH₄), hydrogen (H₂) and nitrogen (N₂). The effects of rf power on the structural properties of CN_x thin films were discussed in this paper. It was found that rf power had significant effects on the growth rate, structural and morphological properties of the deposited films. The point of transition of the growth rate trend marked the equilibrium condition for primary and secondary reactions in growth kinetics of the film with respect to rf power. The films grown at this optimum rf power were most ordered in structure with high surface roughness and had the lowest N incorporation. This work showed that H etching effects and ion bombardment effects increase with increase in rf power and strongly influenced the structure of the CN_x films.     

Electrochemical deposition and evaluation of electrically conductive polymer coating on biodegradable magnesium implants for neural applications

In an attempt to develop biodegradable, mechanically strong, biocompatible, and conductive nerve guidance conduits, pure magnesium (Mg) was used as the biodegradable substrate material to provide strength while the conductive polymer, poly(3,4-ethylenedioxythiophene) (PEDOT) was used as a conductive coating material to control Mg degradation and improve cytocompatibility of Mg substrates. This study explored a series of electrochemical deposition conditions to produce a uniform, consistent PEDOT coating on large three-dimensional Mg samples. A concentration of 1 M 3,4-ethylenedioxythiophene in ionic liquid was sufficient for coating Mg samples with a size of 5 × 5 × 0.25 mm. Both cyclic voltammetry (CV) and chronoamperometry coating methods produced adequate coverage and uniform PEDOT coating. Low-cost stainless steel and copper electrodes can be used to deposit PEDOT coatings as effectively as platinum and silver/silver chloride electrodes. Five cycles of CV with the potential ranging from ?0.5 to 2.0 V for 200 s per cycle were used to produce consistent coatings for further evaluation. Scanning electron micrographs showed the micro-porous structure of PEDOT coatings. Energy dispersive X-ray spectroscopy showed the peaks of sulfur, carbon, and oxygen, indicating sufficient PEDOT coating. Adhesion strength of the coating was measured using the tape test following the ASTM-D 3359 standard. The adhesion strength of PEDOT coating was within the classifications of 3B to 4B. Tafel tests of the PEDOT coated Mg showed a corrosion current (I_CORR) of 6.14 × 10^?5 A as compared with I_CORR of 9.08 × 10^?4 A for non-coated Mg. The calculated corrosion rate for the PEDOT coated Mg was 2.64 mm/year, much slower than 38.98 mm/year for the non-coated Mg.     

Thermal stability of corn oil flavoured with Thymus capitatus under heating and deep-frying conditions

BACKGROUND: The thermal stability of corn oil flavoured with thyme flowers was determined and compared with that of the original refined corn oil (control). The oxidative stability index (OSI) was measured and samples were exposed to heating (30 min at 150, 180 and 200 °C) and deep‐frying (180 °C). Changes in peroxide value (PV), free fatty acid (FFA) content, specific absorptivity values (K₂₃₂ and K₂₇₀), colour and chlorophyll, carotenoid and total phenol contents were monitored. RESULTS: The OSI and heating results showed that thyme incorporation was effective against thermal oxidation based on the increased induction time observed for the flavoured oil (6.48 vs 4.36 h), which was characterised by lower PV, FFA content, K₂₃₂ and K₂₇₀ than the control oil after heating from 25 to 200 °C, with higher red and yellow colour intensities and chlorophyll, carotenoid and total phenol contents. The deep‐frying test showed the accelerated deterioration of both oils in the presence of French fries. CONCLUSION: Compared with the control oil, the thyme‐flavoured oil showed improved thermal stability after heating. This could be attributed to the presence of thyme pigments and antioxidant compounds allowing extended oil thermal resistance. Copyright © 2011 Society of Chemical Industry     

Study of microalgae cultivation systems based on integrated analytic hierarchy process–life cycle optimization

Optimization of sustainable process plant configurations requires the use of systematic assessment methods based on the usage of natural resources, release of pollutants and generation of environmental impact. This paper presents an integrated life cycle optimization framework for the synthesis of microalgae cultivation systems, using a multiple objective linear program formulation; in the model, individual objective functions are aggregated and weighted using the analytic hierarchy process. Four different cultivation alternatives were used as case study to demonstrate the capability of this formulated integrated model. The model takes into account three main environmental criteria in assessing different cultivation alternatives, namely energy, water (direct and indirect water) and carbon footprints. It is determined in the case study that the open pond cultivation system is preferred compared to other alternatives.     

Visual interface for searching and browsing children’s WebOPAC

This study focuses on the visual interface design of WebOPAC, which assists children in carrying out searching and browsing activities for bibliographical information in a library database. The existing interface of WebOPAC, called Ilmu, is investigated in this study; the interface is efficient in retrieving information from the database; however, its poor graphic design causes major usability problems. The graphic design of Ilmu is important in helping children to understand and visualise concepts of searching and browsing. Therefore, the interface must be constructed in such a way that can meet the needs of children aged 7–11 years. In this study, an analysis has been carried out on children’s requirements for the graphic design through participatory design activities using two approaches: cooperative inquiry and sketching of ideas. The cooperative Inquiry approach involved 40 children, while sketching children’s ideas involved 20 children as respondents. A total of 14 requirement specifications were generated and categorised into four areas—use of space, information organisation, function and use of colours; these would serve as a basis in designing a new WebOPAC interface. Synthesis of these requirements has shown that they are best supported through the implementation of visual interface display techniques. Chi-squared (χ ²) test was used to test the responses of children towards the usability of the new interface; the results showed a high level of acceptance by the children, recording a rate of 83.98 %.     

Liposome‐Supported Peritoneal Dialysis for the Treatment of Hyperammonemia‐Associated Encephalopathy

Hyperammonemia can lead to cerebral dysfunction, encephalopathy, coma, and death if not treated adequately. The poor prognosis associated with this condition reflects the unmet medical need for effective ammonia‐lowering treatments. Here, the translational potential of liposome‐supported peritoneal dialysis (LSPD), a recently‐developed detoxification strategy for the removal of small ionizable molecules like ammonia, is described. Dialysis fluids supplemented with micrometer‐sized, transmembrane pH‐gradient liposomes are prepared via an innovative, osmotic shock‐based method overcoming sterilization and long‐term stability issues. LSPD is able to sequester ammonia in healthy rats in relation to the injected dose, buffering capacity of the liposomal core, and membrane composition. In a rat model of cirrhosis, LSPD outperforms conventional peritoneal dialysis in lowering plasmatic ammonia levels and attenuating brain edema. LSPD does not trigger any hypersensitive reaction in pigs, a side effect commonly observed upon the injection of colloids in this animal model and in humans. These findings support the development of LSPD for the treatment of hyperammonemia‐induced encephalopathy.     

Fuzzy analytic hierarchy process (FAHP) for multi-criteria selection of microalgae harvesting and drying processes

Microalgae are considered to be a promising source of biomass compared with first and second generation feedstocks. However, the high energy requirement for harvesting and drying of the algal biomass poses challenge to commercialization due to implications on both carbon footprint (CF) and cost. In this work, we propose a systematic methodology for the multi-criteria evaluation of alternatives for the harvesting and drying processes. A fuzzy analytic hierarchy process (FAHP) approach is used, where the pairwise comparison of the multiple criteria and alternatives were done to prioritize the best harvesting and drying method within the fuzzy bounds of the value judgment that satisfies the consistency index. FAHP also allows the degree of confidence of the expert to be quantified. A case study of four alternatives each for the harvesting and drying process is used to demonstrate the process. Technology capability, cost and environmental impacts (comprised CF, land footprint and water footprint) are identified as the selection criteria for harvesting and drying process, respectively. Results show that flotation is the best alternative for harvesting process, while sun drying is the best among the drying alternatives. Sensitivity analysis is used to give insights on the robustness of the decision model and enables the understanding of critical criteria that would significantly influence the ranking of the alternatives. The proposed FAHP approach therefore can effectively deal with the uncertainty of judgment in the decision-making process in the evaluation of microalgae harvesting and drying processes.