Ferroelectric poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) copolymer 70/30 thin films are prepared by spin coating. The crystalline structure of these films is investigated by varying the annealing temperature from the ferroelectric phase to the paraelectric phase. A hot plate was used to produce a direct and an efficient annealing effect on the thin film. The dielectric, ferroelectric and pyroelectric properties of the P(VDF-TrFE) thin films are measured as a function of different annealing temperatures (80 to 140 °C). It was found that an annealing temperature of 100 °C (slightly above the Curie temperature, Tc) has induced a highly crystalline β phase with a rod-like crystal structure, as examined by X-ray. Such a crystal structure yields a high remanent polarization, Pr = 94 mC/m2, and pyroelectric constant, p = 24 μC/m2K. A higher annealing temperature exhibits an elongated needle-like crystal domain, resulting in a decrease in the crystalline structure and the functional electrical properties. This study revealed that highly crystalline P(VDF-TrFE) thin films could be induced at 100 °C by annealing the thin film with a simple and cheap method.
A mononuclear of [Eu(NO3)(Pic)(H2O)2(EO3)](Pic)·(0.73)H2O complex, where EO3=trietraethylene glycol and Pic=picrate anion, shows a red emission when used as an active layer in a single layer of ITO/EO3-Eu-Pic/Al configuration. The crystal structure of the complex consists of [Eu(NO3)(Pic)(H2O)2(EO3)]+ cation and [Pic]- anion. The Eu(III) ion is coordinated to the 10 oxygen atoms from one EO3 ligand, one Pic anion, one nitrate anion, and two water molecules. The complex is crystallized in triclinic with space group P-1. The hybrids in thin films I and II were prepared in the respective order solution concentrations of 15 and 20 mg/mL the emissive center. Comparing the photoluminescence (PL) and electroluminescence (EL) spectra, we can find that all emissions come from the characteristic transitions of the Eu(III) ion. The EL spectra of both thin films showed the occurrence of the most intense red-light emission around at 612 nm. Comparison of organic light-emitting device (OLED) current intensity characteristics as a function of voltage (I-V) show that the thin film I is better than those found for the thin film II. The thickness of the emitting layer is an important factor to control the current-voltage curve. The sharp and intense emission of the complex at low voltage indicates that the complex is a suitable and promising candidate for red-emitting materials.
A preliminary study was carried out to fabricate a three electrode system based on electrochemical sensoring. The cyclic voltammetry (CV) technique was chosen to select the type of metal suitable for evaporation and to compare the results produced from the fabricated gold electrode with the conventional macro-electrode system. The methodology and apparatus used involved low cost apparatus and methodology such as soft lithography, wet-etching, thermal evaporation, direct current sputtering, polymethylmethacrylate moulding and polydimethylsiloxane coating. The experiment was conducted at a fixed scan rate of 100 mV/s by using 0.01 M K3Fe(CN)6 in 0.1M KCl and well known method using Randles-Sevcik equation, peak current ratio and voltage separation was used to analyze the characterization on the fabricated sensors. Electrodes of 6.5 mm2 and 0.26 mm2 were fabricated to prove the adsorption effect of the reactant and the influence of the electrode area on the value of the peak current. CV analysis proved that the fabricated sensor was reliable for a range of 24 h at 25ºC room temperature.
This paper examines the processing steps of extracting palm oil from fresh fruit bunches in a way that may impact on the formation of chloropropandiol fatty esters (3-MCPD esters), particularly during refining. Diacylglycerols (DAGs) do not appear to be a critical factor when crude palm oils are extracted from various qualities of fruit bunches. Highly hydrolysed oils, in spite of the high free fatty acid (FFA) contents, did not show exceptionally high DAGs, and the oils did not display a higher formation of 3-MCPD esters upon heat treatment. However, acidity measured in terms of pH appears to have a strong impact on 3-MCPD ester formation in the crude oil when heated at high temperatures. The differences in the extraction process of crude palm oil from current commercial processes and that from a modified experimental process showed clearly the effect of acidity of the oil on the formation of 3-MCPD esters. This paper concludes that the washing or dilution step in palm oil mills removes the acidity of the vegetative materials and that a well-optimised dilution/washing step in the extraction process will play an important role in reducing formation of 3-MCPD esters in crude palm oil upon further heat processing.
Mild heat stress promotes thermotolerance and protection against several different stresses in aquatic animals, consequences correlated with the accumulation of heat shock protein 70 (Hsp70). The purpose of this study was to determine if non-lethal heat shock (NLHS) of the Asian green mussel, Perna viridis, an aquatic species of commercial value, promoted the production of Hsp70 and enhanced its resistance to stresses. Initially, the LT50 and LHT for P. viridis were determined to be 42°C and 44°C, respectively, with no heat shock induced death of mussels at 40°C or less. Immunoprobing of western blots revealed augmentation of constitutive (PvHsp70-1) and inducible (PvHsp70-2) Hsp70 in tissue from adductor muscle, foot, gill and mantel of P. viridis exposed to 38°C for 30 min followed by 6 h recovery, NLHS conditions for this organism. Characterization by liquid chromatography-tandem mass spectrometry (LC-MS/MS) revealed that PvHsp70-1 and PvHsp70-2 respectively corresponded most closely to Hsp70 from P. viridis and Mytilus galloprovincialis. Priming of adult mussels with NLHS promoted thermotolerance and increased resistance to V. alginolyticus. The induction of Hsp70 in parallel with enhanced thermotolerance and improved protection against V. alginolyticus, suggests Hsp70 functions in P. viridis as a molecular chaperone and as a stimulator of the immune system.
Dimethyl adipate (DMA) was synthesized by immobilized Candida antarctica lipase B-catalyzed esterification of adipic acid and methanol. To optimize the reaction conditions of ester production, response surface methodology was applied, and the effects of four factors namely, time, temperature, enzyme concentration, and molar ratio of substrates on product synthesis were determined. A statistical model predicted that the maximum conversion yield would be 97.6%, at the optimal conditions of 58.5 degrees C, 54.0 mg enzyme, 358.0 min, and 12:1 molar ratio of methanol to adipic acid. The R(2) (0.9769) shows a high correlation between predicted and experimental values. The kinetics of the reaction was also investigated in this study. The reaction was found to obey the ping-pong bi-bi mechanism with methanol inhibition. The kinetic parameters were determined and used to simulate the experimental results. A good quality of fit was observed between the simulated and experimental initial rates.
The importance and development of industrial biotechnology processing has led to the utilisation of microbial enzymes in various applications. One of the important enzymes is amylase, which hydrolyses starch to glucose. In Malaysia, the use of sago starch has been increasing, and it is presently being used for the production of glucose. Sago starch represents an alternative cheap carbon source for fermentation processes that is attractive out of both economic and geographical considerations. Production of fermentable sugars from the hydrolysis of starches is normally carried out by an enzymatic processes that involves two reaction steps, liquefaction and saccharification, each of which has different temperature and pH optima with respect to the maximum reaction rate. This method of starch hydrolysis requires the use of an expensive temperature control system and a complex mixing device. Our laboratory has investigated the possibility of using amylolytic enzyme-producing microorganisms in the continuous single-step biological hydrolysis of sago flour for the production of a generic fermentation medium. The ability of a novel DNA-recombinated yeast, Saccharomyces cerevisiae strain YKU 107 (expressing alpha-amylase production) to hydrolyse gelatinised sago starch production has been studied with the aim of further utilizing sago starch to obtain value-added products.
This study was conducted in order to optimise simultaneous saccharification and fermentation (SSF) for biobutanol production from a pretreated oil palm empty fruit bunch (OPEFB) by Clostridium acetobutylicum ATCC 824. Temperature, initial pH, cellulase loading and substrate concentration were screened using one factor at a time (OFAT) and further statistically optimised by central composite design (CCD) using the response surface methodology (RSM) approach. Approximately 2.47 g/L of biobutanol concentration and 0.10 g/g of biobutanol yield were obtained after being screened through OFAT with 29.55% increment (1.42 fold). The optimised conditions for SSF after CCD were: temperature of 35 °C, initial pH of 5.5, cellulase loading of 15 FPU/g-substrate and substrate concentration of 5% (w/v). This optimisation study resulted in 55.95% increment (2.14 fold) of biobutanol concentration equivalent to 3.97 g/L and biobutanol yield of 0.16 g/g. The model and optimisation design obtained from this study are important for further improvement of biobutanol production, especially in consolidated bioprocessing technology.
The effects of strontium doping on the electrical and magneto-transport properties of magneto resistive La0.7Ca0.28Sr0.02MnO3 at different sintering temperatures have been studied. The samples were prepared by the co-precipitation technique (COP) and sintered at 1120, 1220 and 1320 oC. XRD patterns revealed that the samples have an orthorhombic structure and the diffraction patterns can be indexed with the Pbnm space group. The insulator metal transition, TIM increased linearly from 261 K to 272 K with the increase in sintering temperature. The magnetoresistance (MR) measurements were made in magnetic fields from 0.1 to 1 T at room temperature. The percentage of MR increased with increasing of magnetic field and sintering temperature for all samples. The electrical resistivity data were fitted with several equations in the metallic (ferromagnetic) and insulator (paramagnetic) regime. The density of states at the Fermi level N(EF) and the activation energy (Ea) of electron hopping were estimated by using variable range hopping and small polaron hopping model.
In this study, zinc oxide (ZnO) nanorod arrays were synthesized using a simple hydrothermal reaction on ZnO seeds/n-silicon substrate. Several parameters were studied, including the heat-treatment temperature to produce ZnO seeds, zinc nitrate concentration, pH of hydrothermal reaction solution, and hydrothermal reaction time. The optimum heat-treatment temperature to produce uniform nanosized ZnO seeds was 400°C. The nanorod dimensions depended on the hydrothermal reaction parameters. The optimum hydrothermal reaction parameters to produce blunt tip-like nanorods (770 nm long and 80 nm in top diameter) were 0.1 M zinc nitrate, pH 7, and 4 h of growth duration. Phase analysis studies showed that all ZnO nanorods exhibited a strong (002) peak. Thus, the ZnO nanorods grew in a c-axis preferred orientation. A strong ultraviolet (UV) emission peak was observed for ZnO nanorods grown under optimized parameters with a low, deep-level emission peak, which indicated high optical property and crystallinity of the nanorods. The produced ZnO nanorods were also tested for their UV-sensing properties. All samples responded to UV light but with different sensing characteristics. Such different responses could be attributed to the high surface-to-volume ratio of the nanorods that correlated with the final ZnO nanorods morphology formed at different synthesis parameters. The sample grown using optimum synthesis parameters showed the highest responsivity of 0.024 A/W for UV light at 375 nm under a 3 V bias.
The effects of thermochemical pretreatment and continuous thermophilic conditions on the composting of a mixture of rice straw residue and cattle manure were investigated using a laboratory-scale composting reactor. Results indicate that the composting period of rice straw can be shortened to less than 10 days by applying alkali pre-treatment and continuous thermophilic composting conditions. The parameters obtained on day 9 of this study are similar to the criteria level published by the Canadian Council of Ministers of the Environment. The moisture content, organic matter reduction, pH level, electrical conductivity, total organic carbon reduction, soluble chemical oxygen demand reduction, total Kjeldahl nitrogen, carbon-to-nitrogen ratio, and germination index were 62.07%, 16.99%, 7.30%, 1058 μS/cm, 17.00%, 83.43%, 2.06%, 16.75%, and 90.33%, respectively. The results of this study suggest that the application of chemical-biological integrated processes under thermophilic conditions is a novel method for the rapid degradation and maturation of rice straw residue.
Thorium is a fertile material that can undergo transmutation for it to become a fissile material,
uranium-233. The fissile material can go through a fission process in order to generate heat energy
and eventually electricity. Most nuclear reactors use uranium as their fission source. The use of
thorium as nuclear fuel has been only investigated for few types of reactors such as a high, temperature
gas reactor (HTGR), fast breeder reactor, light water reactor (LWR) and heavy water reactor
(HWR). For research reactors specifically, there are limited academic publications related to the
la,test u.se of thorium. Hence, the main, interest, of this work is to compile and review the latest
academic publications related to the active use of thorium, for research reactors in particular. The
reviewed studies have been, divided into two categories which are experimented and simulation projects.
The experimental projects are a,bold the ongoing thorium fuel tests that have been carried out. in an
actual, research reactor. On the hand, the simulation work: is related to the computational analysis
performed in predicting the neutronic behaviour of thorium based fuel in research reactors. The
experimented study of thorium is currently active for the KAMINI research reactor. Additionally, most,
simulation works focus on finding criticality and neutron spectra.
An earlier study showed that the behaviour of chitosan-poly(methacrylic acid‑co‑N‑isopropylacrylamide) [chitosan‑p(MAA‑co‑NIPAM)] hydrogels synthesized at different reaction times are affected with regard to their pH and temperature sensitivities. The study was continued in this paper to identify the effects of different reaction times on the degradation, efficiency of rifampicin (Rif) loading and the Rif release profile under two different pH conditions (acidic and basic). The results that were obtained showed that the hydrogel had a faster degradation rate in the acidic condition than in the basic condition, where there was a loss of approximately 50% and 20%, respectively in its original weight within two weeks. The Rif loading efficiency was within 50% and the drug release was controlled by characteristics that were developed beyond the polymerization stages of the synthesis. Therefore, the reaction time for the synthesis of the hydrogel can be considered as a way to control the behaviour of the hydrogel as well as to modify the drug release profile in the chitosan‑p(MAA‑co‑NIPAM) hydrogel.
Numerous mitigation techniques have been incorporated to capture or remove SO2 with flue gas desulfurization (FGD) being the most common method. Regenerative FGD method is advantageous over other methods due to high desulfurization efficiency, sorbent regenerability, and reduction in waste handling. The capital costs of regenerative methods are higher than those of commonly used once-through methods simply due to the inclusion of sorbent regeneration while operational and management costs depend on the operating hours and fuel composition. Regenerable sorbents like ionic liquids, deep eutectic solvents, ammonium halide solutions, alkyl-aniline solutions, amino acid solutions, activated carbons, mesoporous silica, zeolite, and metal-organic frameworks have been reported to successfully achieve high SO2 removal. The presence of other gases in flue gas, e.g., O2, CO2, NOx, and water vapor, and the reaction temperature critically affect the sorption capacity and sorbent regenerability. To obtain optimal SO2 removal performance, other parameters such as pH, inlet SO2 concentration, and additives need to be adequately governed. Due to its high removal capacity, easy preparation, non-toxicity, and low regeneration temperature, the use of deep eutectic solvents is highly feasible for upscale utilization. Metal-organic frameworks demonstrated highest reported SO2 removal capacity; however, it is not yet applicable at industrial level due to its high price, weak stability, and robust formulation.
An improved laboratory technique for measurement of polonium-210(
210Po) in environmental
samples has been developed in Radiochemistry and Environmental Laboratory (RAS), Malaysian
Nuclear Agency. To further improve this technique, a study with the objectives to determine the
optimum conditions for
210Po deposition and; evaluate the accuracy and precision results for
the determination of 2 1 0 P o in environmental samples was carried-out. Polonium-210 which
is an alpha emitter obtained in acidic solution through total digestion and dissolution of samples
has been efficiently plated onto one side of the silver disc in the spontaneous plating process for
measurement of its alpha activity. The optimum conditions for deposition of 210Po were achieved
using hydrochloric acid (HCl) media at acidity of 0.5 M with the presence of 1.0 gram hydroxyl
ammonium chloride and the plating temperature at 90
oC. The plating was carried out in 80 mL
HCl solution (0.5 M) for 4 hours. The recorded recoveries obtained using 2 0 9 P o tracers in
the CRM IAEA-385 and environmental samples were 85% – 98% whereby the efficiency of the
new technique is a distinct advantage over the existing techniques. Therefore, optimization of
deposition parameters is a prime importance to achieve accuracy and precision results as well as
economy and time saving
Along with the mysteries of their ecology, freshwater eels have fascinated biologists for centuries. However, information concerning species diversity, geographic distribution, and life histories of the tropical anguillid eels in the Indo-Pacific region are highly limited. Comprehensive research on the species composition, distribution and habitat use among tropical anguillid eels in the Peninsular Malaysia were conducted for four years. A total of 463 specimens were collected in the northwestern peninsular area. The dominant species was A. bicolor bicolor constituting of 88.1% of the total eels, the second one was A. bengalensis bengalensis at 11.7%, while A. marmorata was the least abundant at 0.2%. A. bicolor bicolor was widely distributed from upstream to downstream areas of the rivers. In comparison, A. bengalensis bengalensis preferred to reside from the upstream to midstream areas with no tidal zones, cooler water temperatures and higher elevation areas. The habitat preference might be different between sites due to inter-species interactions and intra-specific plasticity to local environmental conditions. These results suggest that habitat use in the tropical anguillid eels might be more influenced by ambient environmental factors, such as salinity, temperature, elevation, river size and carrying capacity, than ecological competition, such as interspecific competition.
Response surface methodology-Box–Behnken design (RSM-BBD) was employed to optimize the methyl orange (MO) dye removal efficiency from aqueous solution by cross-linked chitosan-tripolyphosphate/nano-titania compsite (Chi-TPP/NTC). The influence of pertinent parameters, i.e. A: TiO2 loading (0- 50 %), B: dose (0.04-0.14 g), C: pH (4-10), and D: temperature (30-50 oC) on the MO removal efficiency were tested and optimized using RSM-BBD. The F-values of BBD model for MO removal efficiency was 93.4 (corresponding p-value < 0.0001). The results illustrated that the highest MO removal efficiency (87.27 %) was observed at the following conditions: TiO2 loading (50% TiO2), dose (0.09 g), pH = 4.0, and temperature of 40 oC.
This paper presents a comparison on the effects of blending chitin and/or starch with poly(lactic acid) (PLA). Three sets of composites (PLA-chitin, PLA-starch and PLA-chitin-starch) with 92%, 94%, 96% and 98% PLA by weight were prepared. The percentage weight (wt.%) amount of the chitin and starch incorporated ranges from 2% to 8%. The mechanical, dynamic mechanical, thermal and microstructural properties were analyzed. The results from the tensile strength, yield strength, Young's modulus, and impact showed that the PLA-chitin-starch blend has the best mechanical properties compared to PLA-chitin and PLA-starch blends. The dynamic mechanical analysis result shows a better damping property for PLA-chitin than PLA-chitin-starch and PLA-starch. On the other hand, the thermal property analysis from thermogravimetry analysis (TGA) shows no significant improvement in a specific order, but the glass transition temperature of the composite increased compared to that of neat PLA. However, the degradation process was found to start with PLA-chitin for all composites, which suggests an improvement in PLA degradation. Significantly, the morphological analysis revealed a uniform mix with an obvious blend network in the three composites. Interestingly, the network was more significant in the PLA-chitin-starch blend, which may be responsible for its significantly enhanced mechanical properties compared with PLA-chitin and PLA-starch samples.
High temperature tolerance is an important component of adaptation to arid and semiarid cropping environment in chili pepper. Two experiments were carried out to study the genetic variability among chili pepper for heat tolerance and morphophysiological traits and to estimate heritability and genetic advance expected from selection. There was a highly significant variation among the genotypes in response to high temperature (CMT), photosynthesis rate, plant height, disease incidence, fruit length, fruit weight, number of fruits, and yield per plant. At 5% selection intensity, high genetic advance as percent of the mean (>20%) was observed for CMT, photosynthesis rate, fruit length, fruit weight, number of fruits, and yield per plant. Similarly, high heritability (>60%) was also observed indicating the substantial effect of additive gene more than the environmental effect. Yield per plant showed strong to moderately positive correlations (r = 0.23-0.56) at phenotypic level while at genotypic level correlation coefficient ranged from 0.16 to 0.72 for CMT, plant height, fruit length, and number of fruits. Cluster analysis revealed eight groups and Group VIII recorded the highest CMT and yield. Group IV recorded 13 genotypes while Groups II, VII, and VIII recorded one each. The results showed that the availability of genetic variance could be useful for exploitation through selection for further breeding purposes.
Cat's whiskers (Orthosiphon stamineus) leaves extracts were prepared using supercritical CO2 (SC-CO2) with full factorial design to determine the optimum extraction parameters. Nine extracts were obtained by varying pressure, temperature, and time. The extracts were analysed using FTIR, UV-Vis, and GC-MS. Cytotoxicity of the extracts was evaluated on human (colorectal, breast, and prostate) cancer and normal fibroblast cells. Moderate pressure (31.1 MPa) and temperature (60°C) were recorded as optimum extraction conditions with high yield (1.74%) of the extract (B2) at 60 min extraction time. The optimized extract (B2) displayed selective cytotoxicity against prostate cancer (PC3) cells (IC50 28 µg/mL) and significant antioxidant activity (IC50 42.8 µg/mL). Elevated levels of caspases 3/7 and 9 in B2-treated PC3 cells suggest the induction of apoptosis through nuclear and mitochondrial pathways. Hoechst and rhodamine assays confirmed the nuclear condensation and disruption of mitochondrial membrane potential in the cells. B2 also demonstrated inhibitory effects on motility and colonies of PC3 cells at its subcytotoxic concentrations. It is noteworthy that B2 displayed negligible toxicity against the normal cells. Chemometric analysis revealed high content of essential oils, hydrocarbon, fatty acids, esters, and aromatic sesquiterpenes in B2. This study highlights the therapeutic potentials of SC-CO2 extract of cat's whiskers in targeting prostate carcinoma.