Directional solvent extraction is one of the promising membrane-less seawater desalination method. This technique was not extensively investigated due the poor mixing and separation performances of its bench-scale system. It is believed that, overcoming these drawbacks is possible now with the rapid development of microfluidics technology that enabled high-precession micro mixing and separation. This work presents microfluidics chip for extracting and separating salt from seawater. The chip was designed with two sections for extraction and separation. In both sections, the liquids were separated using capillary channels perpendicular to the main stream. The main channels were designed to be 400 µm in width and 100 µm in height. Two streams inlets were introduced through a Y-junction containing octanoic acid as the organic phase and saltwater as the aqueous phase. The desalination performance was investigated at four different temperatures and five different solvent flow rates. Water product salinity was recorded to be as low as 0.056% (w/w) at 60 °C and 40 mL/h. A maximum water yield of 5.2% was achieved at 65 °C and 40 mL/h with a very low solvent residual (70 ppm). The chip mass transfer efficiency was recorded to be as high as 68% under similar conditions. The fabricated microfluidic desalination system showed a significant improvement in terms of water yield and separation efficiency over the conventional macroscale. The high performance of this microsystem resulted from its ability to achieve a high mixing efficiency and separate phases selectively and that will provide a good platform in the near future to develop small desalination kits for personal use.
Tropical peat swamp forest (PSF) is one of the most endangered ecosystems in the world. However, the impacts of
anthropogenic activities in PSF and its conversion area towards fish biodiversity are less understood. This study
investigates the influences of water physico-chemical parameters on fish occurrences in peat swamp, paddy field and
oil palm plantation in the North Selangor peat swamp forest (NSPSF), Selangor, Malaysia. Fish and water samples were
collected from four sites located in the peat swamps, while two sites were located in the paddy field and oil palm plantation
areas. Multivariate analyses were used to determine the associations between water qualities and fish occurrences in
the three habitats. A total of 1,382 individual fish, belonging to 10 families, 15 genera and 20 species were collected.
The family Cyprinidae had the highest representatives, followed by Bagridae and Osphronemidae. The most abundant
species was Barbonymus schwanefeldii (Bleeker 1854), while the least abundant was Wallago leerii Bleeker, 1851. The
paddy field and oil palm plantation area recorded significantly higher fish diversity and richness relative to peat swamp
(p<0.05). The water physico-chemical parameters, such as pH, DO, NH3
-N, PO4, SO4
, and Cl2 showed no significant
difference between paddy field and oil palm plantation (p>0.05), but was significantly different from the peat swamp
(p<0.05). However, no water quality parameter was consistently observed to be associated with fish occurrences in all
of the three habitats, but water temperature, NH3
-N, Cl2, SO4
, and EC were at least associated with fish occurrences in
two habitats studied. This study confirmed that each habitat possess different water quality parameters associated with
fish occurrences. Understanding all these ecological aspects could help future management and conservation of NSPSF.
Mixed culture sludge has been widely used as a microbial consortium for biohydrogen production. Simple thermal treatment of sludge is usually required in order to eliminate any H2-consuming bacteria that would reduce H2 production. In this study, thermal treatment of sludge was carried out at various temperatures. Electron flow model was then applied in order to assess community structure in the sludge upon thermal treatment for biohydrogen production. Results show that the dominant electron sink was acetate (150-217 e- meq/mol glucose). The electron equivalent (e- eq) balances were within 0.8-18% for all experiments. Treatment at 100 °C attained the highest H2 yield of 3.44 mol H2/mol glucose from the stoichiometric reaction. As the treatment temperature increased from 80 to 100 °C, the computed acetyl-CoA and reduced form of ferredoxin (Fdred) concentrations increased from 13.01 to 17.34 e- eq (1.63-2.17 mol) and 1.34 to 4.18 e- eq (0.67-2.09 mol), respectively. The NADH2 balance error varied from 3 to 10% and the term e-(Fd↔NADH2) (m) in the NADH2 balance was NADH2 consumption (m = -1). The H2 production was mainly via the Fd:hydrogenase system and this is supported with a good NADH2 balance. Using the modified Gompertz model, the highest maximum H2 production potential was 1194 mL whereas the maximum rate of H2 production was 357 mL/h recorded at 100 °C of treatment.
The contribution of palm oil fuel ash (POFA), an agricultural waste as a low cost adsorbent for the removal of arsenite (As(III)) and arsenate (As(V)) was explored. Investigation on the adsorbency characteristics of POFA suspension revealed that the surface area, particle size, composition, and crystallinity of the SiO2 rich mullite structure were the crucial factors in ensuring a high adsorption capacity of the ions. Maximum adsorption capacities of As(III) and As(V) at 91.2 and 99.4 mg g-1, respectively, were obtained when POFA of 30 μm particle size was employed at pH 3 with the highest calcination temperature at 1150 °C. An optimum dosage of 1.0 g of dried POFA powder successfully removed 48.7% and 50.2% of As(III) and As(V), respectively. Molecular modeling using the density functional theory consequently identified the energy for the proposed reaction routes between the SiO- and As+ species. The high stability of the POFA suspension in water in conjunction with good adsorption capacity of As(III) and As(V) seen in this study, thus envisages its feasibility as a potential alternative absorbent for the remediation of water polluted with heavy metals.
Interesterification reaction involves rearrangement of the fatty acid radicals on the glycerol backbone, either randomly (chemical interesterification) or regioselectivity (enzymatic interesterification). Refined, bleached and deodourised palm oil (RBDPO) and palm kernel oil (RBDPKO) were blended in ratios from 25:75 to 75:25 (wt/wt). All blends were subjected to enzymatic (EI) and chemical interesterification (CI) using Lipozyme TL IM (4% w/w) and sodium methoxide (0.2% m/m) as the catalysts, respectively. The effect of EI and CI on the triacylglycerol (TAG) composition, thermal behaviour, polymorphism, crystal morphology and crystallisation kinetics were studied. The aim of this research is to characterise the nature of crystals in food product for certain desired structure. The crystallisation behaviour discussed in this study involves microstructure (PLM), polymorphism (XRD), thermal properties and crystallisation kinetics by DSC. The alteration in TAG composition was greater after CI as compared to EI with the reduction of LaLaLa (from 11.00% to 5.15%) and POO (from 14.28% to 4.87%). The DSC complete melting and crystallisation temperature of blend with 75% PO increased after CI, from 39.58 °C to 41.67 °C and from -30.84 °C to -28.33 °C, respectively. EI contributed to finer crystals than CI. However, the β' and β polymorph mixture and crystallisation kinetics (n = 2) of PO-PKO blends did not change after CI and EI. The knowledge on controlling crystallisation of RBDPO and RBDPKO blends is vital for proper processing condition like margarine production.
The carbonation rate of reinforced concrete is influenced by three parameters, namely temperature, relative humidity, and concentration of carbon dioxide (CO₂) in the surroundings. As knowledge of the service lifespan of reinforced concrete is crucial in terms of corrosion, the carbonation process is important to study, and high-performance durable reinforced concretes can be produced to prolong the effects of corrosion. To examine carbonation resistance, accelerated carbonation testing was conducted in accordance with the standards of BS 1881-210:2013. In this study, 10⁻30% of micro palm oil fuel ash (mPOFA) and 0.5⁻1.5% of nano-POFA (nPOFA) were incorporated into concrete mixtures to determine the optimum amount for achieving the highest carbonation resistance after 28 days water curing and accelerated CO₂ conditions up to 70 days of exposure. The effect of carbonation on concrete specimens with the inclusion of mPOFA and nPOFA was investigated. The carbonation depth was identified by phenolphthalein solution. The highest carbonation resistance of concrete was found after the inclusion of 10% mPOFA and 0.5% nPOFA, while the lowest carbonation resistance was found after the inclusion of 30% mPOFA and 1.5% nPOFA.
In this study, Gelidium elegans is investigated for ethanol production. A combination of factors including different temperatures, acid concentration and incubation time was evaluated to determine the suitable saccharification conditions. The combination of 2.5% (w/v) H2SO4 at 120 °C for 40 min was selected for hydrolysis of the seaweed biomass, followed by purification, and fermentation to yield ethanol. The galactose and glucose were dominant reducing sugars in the G. elegans hydrolysate and under optimum condition of dilute acid hydrolysis, 39.42% of reducing sugars was produced and fermentation resulted in ethanol concentration of 13.27 ± 0.47 g/L. A modified method was evaluated for sample preparation for gas chromatography (GC) analysis of the ethanol content. A solvent mixture of acetonitrile and iso-butanol precipitated dissolved organic residues and reduced water content in GC samples at least by 90%. Results showed that this method could be successfully used for bioethanol production from seaweed.
Refined palm-pressed mesocarp fibre oil (PPFO), which can be obtained from one of the by-products of palm oil milling, palm-pressed mesocarp fibre, is categorized as palm sludge oil. So far, it has been given less attention and underutilized until some recent scientific reports revealing its high content of phytonutrients, carotenoids and vitamin E, which have been proven scientifically to possess anti-oxidant activity. The study evaluated the stability of PPFO as a carrier for plant-based emulsion. PPFO was extracted and examined for its positional distribution of fatty acids, saturation levels and iodine value (IV) using NMR spectroscopy. The PPFO-based emulsion was then prepared and subjected to stability tests, including temperature variation, centrifuge test, cycle test, pH and slip melting point for 28 days. Phase separation was observed from PPFO-based emulsion stored at 40℃ from day-21 onwards while no creaming found in all the palm olein-based emulsions stored at the three storage temperatures. Nevertheless, results indicated that the PPFO-based emulsion passed all the tests above showing insignificant phase separation (p > 0.05) compared with those of palm olein commonly used in emulsion preparation. The findings suggested that PPFO enriched with valuable phytonutrients could be used as an alternative carrier oil in emulsion formulation, which is an important component in personal care products.
Fission tracks are linear trails of intense radiation damage in the crystal structure of a mineral, produced by spontaneous fissioning of uranium-238 (238U) atoms. Detail information on the low-temperature thermal histories of rocks, below∼120 °C for tracks in apatite and below∼350 °C for zircon, can be provided by Fission-track (FT) analysis. The purpose of this article is to present apatite and zircon fission-track data, and U-Pb granite ages that provide information about the cooling histories of a rock which can be crucial in comprehending the exhumation episodes of the study area, in particular, and the region, in general. Granite samples were collected along the same vertical profile at different elevation, 178-944 m.a.s.l. These samples were used to determine Fission-Track and crystallization ages. HeFTy software was employed to interpret the cooling histories of the samples using forward and inverse models. The inverse model was an approach of reproducing the observed data, and it was carried out only for fission-track data from the apatite grains. And it was constructed after generating a number of forward models, where in each of these models the predicted apatite fission-track parameters were compared to the measured values. The apatite fission track (AFT) and zircon fission track (ZFT) data indicated expected age trends, i.e. the older ages at higher elevations and the younger ages at lower elevations. Similarly, the data shows that the apatite and zircon FT ages appear younger than the age of the rock crystallization. The U-Pb age in zircon consistently suggest the age of the granite is Late Triassic.
The spread of graphene in low-density polyethylene (LDPE) improves LDPE/graphene nanocompounds' thermal/mechanical/electrical characteristics. The images of scanning electron microscopy (SEM) verify full graphene exfoliation at 1000 °C. Inclusion graphene develops crystallinity; increases the local order of lattice and thermal stability of LDPE/graphene nanocompounds. The consistent distributions and further inclusion of graphene caused the great heat breakdown strength, increasing heat breakdown activation energy and a superior melting point (Tm) for LDPE nanocompounds. Percolation occurs with the graphene incorporation of 0.5 wt%. The complex viscosity test showed Newtonian behavior for LDPE at a very low frequency. But, graphene inclusion to LDPE changed the viscosity performance from liquid-like to solid-like which caused a decrease in the melt flow rate (MFR) values for all LDPE/graphene nanocompounds.
To overcome the critical limitations of liquid-electrolyte-based dye-sensitized solar cells, quasi-solid-state electrolytes have been explored as a means of addressing long-term device stability, albeit with comparatively low ionic conductivities and device performances. Although metal oxide additives have been shown to augment ionic conductivity, their propensity to aggregate into large crystalline particles upon high-heat annealing hinders their full potential in quasi-solid-state electrolytes. In this work, sonochemical processing has been successfully applied to generate fine Co3O4 nanoparticles that are highly dispersible in a PAN:P(VP-co-VAc) polymer-blended gel electrolyte, even after calcination. An optimized nanocomposite gel polymer electrolyte containing 3 wt % sonicated Co3O4 nanoparticles (PVVA-3) delivers the highest ionic conductivity (4.62 × 10-3 S cm-1) of the series. This property is accompanied by a 51% enhancement in the apparent diffusion coefficient of triiodide versus both unmodified and unsonicated electrolyte samples. The dye-sensitized solar cell based on PVVA-3 displays a power conversion efficiency of 6.46% under AM1.5 G, 100 mW cm-2. By identifying the optimal loading of sonochemically processed nanoparticles, we are able to generate a homogenous extended particle network that effectively mobilizes redox-active species through a highly amorphous host matrix. This effect is manifested in a selective 51% enhancement in photocurrent density (JSC = 16.2 mA cm-2) and a lowered barrier to N719 dye regeneration (RCT = 193 Ω) versus an unmodified solar cell. To the best of our knowledge, this work represents the highest known efficiency to date for dye-sensitized solar cells based on a sonicated Co3O4-modified gel polymer electrolyte. Sonochemical processing, when applied in this manner, has the potential to make meaningful contributions toward the ongoing mission to achieve the widespread exploitation of stable and low-cost dye-sensitized solar cells.
Ethylene glycol in the presence of sodium hydroxide was utilised as pretreatment for effective delignification and reduced the recalcitrance of lignocellulosic biomass which ramified the exposure of cellulose. Two-staged acid hydrolysis was also investigated which demonstrated its synergistic efficiency by minimising the deficiency of single stage acid hydrolysis. The operating parameters including acid concentration, temperature, residence time and cellulose loading for two-staged acid hydrolysis were studied by using ethylene glycol delignified degraded oil palm empty fruit bunch (DEFB) to recover the sugar based substrates for potential biofuels and other bio-chemicals production. In this study, stage I 45 wt% acid at 65 °C for 30 min coupled with high cellulose loading 21.25 w/v% and 12 wt% acid at 100 °C for 120 min was able to release a total of 89.8% optimum sugar yield with minimal formation of degradation products including 0.058 g/L furfural, 0.0251 g/L hydroxymethylfurfural and 0.200 g/L phenolic compounds.
An upsurge in sustainable energy demands has ultimately made supercapattery one of the important choice for energy storage, owing to highly advantageous energy density and long life span. In this work, novel strontium based mixed phased nanostructures were synthesized by using probe sonicator with sonication power 500 W at frequency of 20 kHz. The synthesized material was subsequently calcined at different temperature ranging from 200 to 800 °C. Structural and morphological analysis of the synthesized materials reveals the formation of mixed particle and rod like nanostructures with multiple crystal phases of strontium oxides and carbonates. Crystallinity, grain size and morphology of grown nanomaterials significantly improved with the increase of calcination temperature due to sufficient particle growth and low agglomeration. The electrochemical performance analysis confirms the redox activeness of the Sr-based electrode materials. Material calcined at 600 °C show high specific capacitance of 350 F g-1 and specific capacity of 175 C g-1 at current density of 0.3 A g-1 due to less particle agglomeration, good charge transfer and more contribution of electrochemical active sites for redox reactions. In addition, the developed supercapattery of Sr-based nanomaterials//activated carbon demonstrated high performance with maximum energy density of 21.8 Wh kg-1 and an excellent power density of 2400 W kg-1 for the lower and higher current densities. Furthermore, the supercapattery retain 87% of its capacity after continuous 3000 charge/discharge cycles. The device characteristics were further investigated by analyzing the capacitive and diffusion controlled contributions. The versatile strategy of developing mixed phased nanomaterials pave the way to synthesize other transition metal based nanomaterials with superior electrochemical performance for hybrid energy storage devices.
Time and temperature parameters of superheated steam (SHS) treatment were optimised using response surface methodology (RSM) for specific lipoxygenase (LOX) activity in soya beans and crude protein content in soya milk. The optimal SHS treatment was obtained at 9.3 min and 119 °C. The predicted values of specific LOX activity and crude protein content by RSM were 0.0098 μmol/(min mg protein) and 3.2%, respectively. These values were experimentally verified to be 0.0081 ± 0.0002 μmol/(min mg protein) and 3.0 ± 0.1%, respectively. Sensory evaluation showed that the beany flavour of soya milk produced from SHS treated soya beans was significantly weaker (P
A suitable and cost-effective microfabrication technique for processing aluminum micropart is required, as the choice
of aluminum microparts for aerospace, electronics and automobile components is preferred over other metals due to its
excellent properties. Meanwhile, powder injection molding (PIM) is identified as an economical manufacturing technique
for processing ceramic and micro-metal powders into microparts and or components. Therefore, this study investigates
formulation and processing of aluminum PIM feedstock using a custom-made machine. The investigation is focused on
the effect of mixing process parameters (powder loading, rotor speed and mixing temperature) and the suitability of
the backbone polymer. The formulated PIM feedstock constituents are paraffin wax (PW), stearic acid (SA), high-density
polyethylene (HDPE)/ medium-density polyethylene (MDPE) alternatively and aluminum micro-metal powder. Taguchi
method is used for the design of experiments (DOEs) and analysis. In addition, response surface methodology (RSM) is
employed to develop empirical viscosity models. The optimum powder-binder mixing ratio of 58:42 vol. % with rotor
speed of 43 rpm were determined for preparing aluminum PIM feedstock using mini-lab mixer developed. The empirical
model developed for aluminum PIM feedstock viscosity shows a good fit with R2
values of 0.84 using HDPE and 0.96 for
MDPE binder system. This investigation demonstrates preparation and suitability of aluminum PIM feedstock using waxbased
binder system.
Thrips (Thysanoptera) are common pests on legume plants, yet little is known about their ecology or diversity in Peninsular
Malaysia. In legumes, thrips are typically found in flowers, where their feeding activity causes malformations that
eventually lead to crop damage. In this study, we examined the diversity of thrips species, particularly Megalurothrips
usitatus, in three selected legume farms around Peninsular Malaysia (Janda Baik, Pahang; Bestari Jaya, Selangor; and
Jelebu, Negeri Sembilan). Each month from April 2013 to May 2014, depending on growing season, legume flowers were
inspected for thrips in five random plots from each farm. Sampling was performed six times in Bestari Jaya and Jelebu
and twelve times in Janda Baik. The most abundant thrips species on legumes was M. usitatus (89.97%) followed by
Thrips parvispinus (9.77%), T. hawaiiensis (0.13%) and Ceratothripoides brunneus (0.12%). The abundance of M. usitatus
was not different between long bean, French bean and winged bean which equally distributed among different arbitrary
strata on legume plants. Temperature and light intensity were found to be positively correlated with the abundance of
M. usitatus, but relative humidity showed a negative relationship. M. usitatus was found in large numbers during hot
and dry months, but in lower numbers during raining season. This study suggested that wet season may help to regulate
the populations of M. usitatus on legume plants.
Reference evapotranspiration (ET0) plays a fundamental role in irrigated agriculture. The objective of this study is to simulate monthly ET0 at a meteorological station in India using a new method, an improved support vector machine (SVM) based on the cuckoo algorithm (CA), which is known as SVM-CA. Maximum temperature, minimum temperature, relative humidity, wind speed and sunshine hours were selected as inputs for the models used in the simulation. The results of the simulation using SVM-CA were compared with those from experimental models, genetic programming (GP), model tree (M5T) and the adaptive neuro-fuzzy inference system (ANFIS). The achieved results demonstrate that the proposed SVM-CA model is able to simulate ET0 more accurately than the GP, M5T and ANFIS models. Two major indicators, namely, root mean square error (RMSE) and mean absolute error (MAE), indicated that the SVM-CA outperformed the other methods with respective reductions of 5-15% and 5-17% compared with the GP model, 12-21% and 10-22% compared with the M5T model, and 7-15% and 5-18% compared with the ANFIS model, respectively. Therefore, the proposed SVM-CA model has high potential for accurate simulation of monthly ET0 values compared with the other models.
Nowadays Silicone Rubber (SiR) is recommended in high voltage cable accessories fabrication as it offers excellent electrical and mechanical properties. Electrical tree is one of the phenomenon which contributes to the main factor of SiR insulation breakdown. Recently, a new approach has been applied in order to enhance the insulation strength properties by introducing nano filler in undoped material. Thus, this paper presents the influence of nano-alumina and halloysite nanoclay on electrical tree growth in SiR at 0, 1 vol%, 2 vol% and 3 vol% concentration. The electrical tree growth was investigated at 8kVrms after tree inception voltage (TIV) within 30 minutes under room temperature. The results show reductions of electrical tree growth speed and accumulate damage (%) up to 2 vol% nano-alumina and up to 3 vol% halloysite nanoclay. Nevertheless the presence of 3 vol% nano-alumina in SiR leads to the faster electrical tree growth rate and the worst accumulate damage within 1 minute of electrical tree growth process.
Granulation is an important step during the production of urea granules. Most of the commercial binders used for granulation are toxic and non-biodegradable. In this study, a fully biodegradable and cost-effective starch-based binder is used for urea granulation in a fluidized bed granulator. The effect of binder properties such as viscosity, surface tension, contact angle, penetration time, and liquid bridge bonding force on granulation performance is studied. In addition, the effect of fluidized bed process parameters such as fluidizing air inlet velocity, air temperature, weight of primary urea particles, binder spray rate, and binder concentration is also evaluated using response surface methodology. Based on the results, binder with higher concentration demonstrates higher viscosity and higher penetration time that potentially enhance the granulation performance. The viscous Stokes number for binder with higher concentration is lower than critical Stokes number that increases coalescence rate. Higher viscosity and lower restitution coefficient of urea particles result in elastic losses and subsequent successful coalescence. Statistical analysis indicate that air velocity, air temperature, and weight of primary urea particles have major effects on granulation performance. Higher air velocity increases probability of collision, whereby lower temperature prevents binder to be dried up prior to collision. Findings of this study can be useful for process scale-up and industrial application.
In this paper, a facile synthesis method for CaFe2O4 is introduced that produces a catalyst capable of significant photocatalytic degradation of POME under visible light irradiation. The co-precipitation method was used to produce two catalysts at calcination temperatures of 550 °C and 700 °C dubbed CP550 and CP700. CP550 demonstrated the maximum COD removal of 69.0% at 0.75 g/L catalyst loading after 8 h of visible light irradiation which dropped to 61.0% after three consecutive cycles. SEM images indicated that the higher calcination temperature of CP700 led to annealing which reduced the pore volume (0.025 cm3/g) and pore diameter (10.3 nm) while simultaneously creating a smoother and more spherical surface with lower SBET (9.73 m2/g). In comparison, CP550 had a rough hair-like surface with higher SBET (27.28 m2/g) and pore volume (0.077 cm3/g) as evidenced by BET analysis. XRD data indicated the presence of CaFe5O7 in the CP550 composition which was not present in CP700. The presence of Wustite-like FeO structures in CaFe5O7 are likely the cause for lower photoluminescence intensity profile and hence better charge separation of CP550 as these structures in CaFe2O4 have been known to increase resistivity and electron localization. The COD removal of CP550 dropped from 69.0% to just 7.0% upon adding a small quantity of isopropanol into the reaction mixture indicating hydroxyl radicals as the primary reactive oxidative species.