The objective of this research is recovery of squalene from palm fatty acid distillate (PFAD) using supercritical fluid extraction (SFE). The extraction process was performed by using the SFE and recovered squalene was analyzed from total lipid extracts using HPLC. A central composite design was used to study the effect of SFE variables namely pressure (X₁) from 200 to 400 bar and temperature (X₂) from 40 to 60⁰C on the total lipid extracts (Y₁) and squalene concentration (Y₂) and optimize the SFE conditions. The nonlinear regression equations were significantly (p < 0.05) fitted for both responses with high R₂ (> 0.965), which had no indication of lack of fit. The results indicated that a combined pressure (200 bar) and temperature (50⁰C) was predicted to provide the optimum region in terms of total lipid extracts (13.84 ± 0.52%) and squalene concentration (418.31 ± 18.40 ppm) studied.
Introduction: A prebiotic such as inulin is a well-known functional plant food ingredient. It is capable of stimulating growth of beneficial bifidobacteria in the intestine thus protecting against intestinal infections, preventing constipation, increasing mineral absorption, reducing the incidence of colon cancer, and producing B vitamins. Inulin added to food therefore has to be stable during food processing especially against heat treatment, low pH and Maillard reaction. Methods: Newly developed dark chocolate, DC-1, containing inulin (replacing sugar component) as an added value, was stored at 18oC, 60% relative humidity and 25oC, 80% relative humidity (RH) to determine shelf life stability compared to control dark chocolate, DC-0 (with high content of sugar). Sensory evaluation (quantitative descriptive analysis), water activity (aw), microbiological content and presence of inulin after storage of the prebiotic chocolate under both conditions were evaluated to determine shelf life. Results: The DC-1 chocolate had at least 12 months of shelf life at 18oC, 60% RH with better acceptance than DC-0; moreover, it did not experience microbiological and inulin content changes. At 25oC, 80% RH, the growth of Aspergillus sp. was observed on the surface of both DC-0 and DC-1 with aw >0.50 after a 2-month storage. Conclusion: Shelf life stability of DC-1 is almost similar to DC-0.
Transition metals play an important role in the growth of carbon nanotubes (CNTs). Series of unsupported hybrid catalysts consisting of Ni:Cu, Ni:Cr, and Ni:Mn doped with Nd catalyst, respectively were synthesized by impregnation method. The catalytic performance of the catalyst for the production of CNTs was measured in the pyrolysis process of hydrocarbon source by catalytic chemical vapour deposition method. Acetylene gas was used as the source of carbon in the pyrolysis process. The decomposition of acetylene was carried out at 700ºC. The bulk properties of the catalysts were investigated by X-ray diffraction. Field emission scanning electron microscopy and thermal analysis were used to observe the morphology and thermal stability of the as-synthesized CNTs, respectively. Hybrid catalyst of Ni:Mn/Nd and Ni:Cr/Nd in 3:1 atomic ratio gave high percentage of carbon yield which was assigned for the high production of CNTs with the mass of yield 18 times greater than the initial mass of the catalyst used.
The production of ethanol, from glucose in batch and fed batch culture, was investigated. In the fed batch culture, the glucose feeding was added into the culture at 16th hour of fermentation. The effects of different glucose concentration feeding rates on ethanol fermentation were investigated for fed batch culture. The 2gL-1hr-1 glucose concentration feeding rate was found to give higher ethanol yield (2.47 g ethanol g glucose-1), with respect to substrate consumed as compared to 8 gL-1hr-1 (0.23 g ethanol g glucose-1) and 4 gL-1hr-1 (0.20 g ethanol g glucose-1). The ethanol yield with respect to substrate consumed obtained in batch culture was 0.81 g ethanol g glucose-1. The fed batch culture at 2 gL-1hr-1 glucose concentration feeding rate was proven to be a better fermentation system than the batch culture. The specific growth rate, specific glucose consumption rate and specific ethanol production rate for the fed batch fermentation, at 2 gL-1hr-1 glucose concentration feeding rate, were 0.065 hr-1, 1.20 hr-1 and 0.0009 hr-1, respectively.
Texture evolution of NiO formed during oxidation of polycrystalline single oriented (100) Ni-Cr was investigated. This foil was also termed rolling assisted biaxially textured substrate (RABiTS). X-ray diffractograms of oxidized Ni-Cr RABiTS foil showed the existence of mostly (200) NiO indicating (100)-type NiO formed exclusively on (100) singly oriented Ni-Cr grains. Epitaxial relationship between the two layers is observed. However the dual-in-plane texture was recorded.
The in-plane texture was assessed by conducting phi scan and plotting series of pole figures measured at (111) NiO peak. The mechanism of the oxides formation was proposed to take into account the formation of (100)-type NiO. Cross section morphology of the oxidised foils reveals two oxidation layers; fast growing external layer consisting of the (100)-type NiO and an internal layer consisted of mostly Cr2O3 and maybe NiCr2O4. The thickness of NiO was ~ 10Pm. Cr2O3 formed as needle-like oxides embedded in a matrix of Ni foil. Inward diffusion of oxygen is believed to have caused this to happen. The external NiO layer was consisted of duplex microstructure characterised by columnar layer growing vertical on the surface of the metal and a few micron thick of equiaxed NiO. Delamination of the outer NiO layer often occurred at the columnarequiaxed interface which could be cured by CeO2 deposition on the foil prior to the oxidation process. CeO2 was deposited by conversion immersion using Ce(NO3)3.6H2O solution. (200) NiO formed on this coated sample as well.
Effects of cultural practice under different habitats, of well-managed monoculture plantation and growing wild under rubber trees, were studied in Aquilaria malaccensis (Karas) leaves. This study was carried out on Karas growing in these two habitats each from Lipis, Pahang and Sepang, Selangor areas in Malaysia; under the control and induced treatments. The parameters studied include wet and dry weight of 50 matured leaves, iron and zinc elemental contents in leaf, iron and zinc uptakes from soil, and leaf and soil moisture contents. Iron and zinc were analysed in Karas leaves and soil by using Instrumental Neutron Activation Analysis (INAA) technique.
Ocular abnormalities have apparent effects on brain activation. However, neuroimaging data about the ocular characteristics of healthy participants are still lacking to be compared with data for patients with ocular pathology. The objective of this multiple participants’ functional magnetic resonance imaging (fMRI) studies was to investigate the brain activation characteristics of healthy participants when they view stimuli of various shapes, pattern and size. During the fMRI scans, the participants view the growing ring, rotating wedge, flipping hour glass/bow tie, quadrant arc and full checker board stimuli. All stimuli have elements of black-and-white checkerboard pattern. Statistical parametric mapping (SPM) was used in generating brain activation via fixed-effects (FFX) and conjunction analyses. The stimuli of various shapes, pattern and size produce different brain activation with more activation concentrated in the left hemisphere. These results are supported by the conjunction analysis which indicated that the left pre-central, post-central, superior temporal and occipital gyrus as well as the left cingulate cortices were involved when the participants viewed each given stimulus. Differential activation analysis showed activation with high specificity in the occipital region due to the stimuli of various shapes, pattern and size. The activation in the right middle temporal gyrus was found to be significantly higher in response to moving stimuli as compared to stationary stimuli. This confi rms the involvement of the right middle temporal gyrus in the observation of movements. The black-and-white checkerboard stimuli of various shapes, pattern and size, stationary and moving was found to 1) activate visual as well as other cortices in temporal and parietal lobes, 2) cause asymmetry in brain function and 3) exhibit functional integration characteristics in several brain areas.
Keywords: fMRI; SPM; visual stimulus; occipital gyrus; middle temporal gyrus
Silicon nanowires were synthesized on Si substrates (111) via thermal evaporation using AuPd thin layer catalyst. Pre cleaned of Si wafer was used as a substrate to assemble the nanostructure products. In this work, the effect of growth temperature that ranging from 800 to 1000°C on the formation of silicon nanowires studied extensively. X-ray diffraction and field emission scanning electron microscope were employed to characterize the structures and morphology of nanowires. Vertical aligned silicon nanowires have been successfully grown on Si substrates at 900 and 1000°C. At 1100°C, the high aspect ratio of silicon nanowires can be produced but the formation density is low. The presence of AuPd catalyst on the tip of nanowires, it is expected that VLS is the most suitable to explain the growth mechanism of obtained SiNWs. The crystalline structure of SiNWs was proved by XRD data.
Nuclear grade (high-purity) graphite for fuel element and moderator material in Advanced Gas
Cooling Reactors (AGR) displays large scatter in strength and a non-linear stress-strain response from the damage accumulation. These responses can be characterized as quasi-brittle behaviour. Current assessments of fracture in core graphite components are based on the linear elastic approximation and thus represent a major assumption. The quasi-brittle behaviour gives challenge to assess the real nuclear graphite component. The selected test method would help to bridge the gap between microscale to macro-scale in real reactor component. The small scale tests presented here can contribute some statistical data to manifests the failure in real component. The evaluation and choice of different solution design of biaxial test will be discussed in this paper. The ball on-three ball test method was used for assessment test follows by numerous of analytical method. The results shown that biaxial strength of the EY9 grade graphite depends on the method used for evaluation. Some of the analytical methods use to calculate biaxial strength were found not to be valid and therefore should not be used to assess the mechanical properties of nuclear graphite.
The detection of tetrodotoxin (TTX) and saxitoxin (STX) in dried salted yellow puffer fish (Xenopterus naritus) eggs bought from Satok Market, Kuching, Sarawak was carried out by mouse bioassay method. The amount of TTX and STX detected in the samples ranged from 95.6-195.5 Mouse Unit (MU)/g and 1.72-3.58 MU/g respectively. The results indicate that the dried salted eggs samples were found to contain TTX 9-20 times above the regulatory limit for human consumption (10 MU/g). Although detected, the amount of STX in salted eggs extract was slightly below the accepted threshold limit (4 MU/g). The local public in Sarawak should be educated on the potential danger of consuming dried salted puffer fish eggs in addition to the current warnings on puffer fish.
This paper presents investigations into the development of control schemes for end-point vibration
suppression and input tracking of a flexible manipulator. A constrained planar single-link flexible manipulator is considered and the dynamic model of the system is derived using the assumed mode method. To study the effectiveness of the controllers, a Linear Quadratic Regulator (LQR) was initially developed for control of rigid body motion. This is then extended to incorporate a noncollocated PID controller and a feedforward controller based on input shaping techniques to control vibration (flexible motion) of the system. For feedforward controller, positive and modified specified negative amplitude (SNA) input shapers are proposed and designed based on the properties of the system. Results from the simulation of the manipulator responses with the controllers are presented in time and frequency domains. The performances of the control schemes are assessed in terms of level of vibration reduction, input tracking capability and time response specifications. Finally, a comparative assessment of the control techniques is presented and discussed.
The microstructural evolution of Sn-40Pb/Cu joints has been investigated under 125 o C thermal exposure conditions using single shear lap joints. A scanning electron microscope (SEM) was used to observe the morphology of the phases and energy dispersive x-ray (EDX) was used to estimate the elemental compositions of the phases. A double layer of Cu6Sn5 and Cu3Sn were observed. The Cu6Sn5 developed with a scalloped morphology, while the Cu3Sn always grew as a somewhat undulated planar layer in phase with the Cu6Sn5. The Cu6Sn5 layer began to transform from scallop shape to planar type after aging for 375 hours due to reduction in the interfacial energy. The intermetallic layers showed a linear dependence on the square root of aging time. The growth rate constant of the intermetallic compounds are estimated as 15.2 x 10 - 14 and 0.152 x 10 -14 cm 2 /s for Cu6Sn5 and Cu3Sn intermetallic, respectively.
The state of Selangor, Malaysia, is facing a significant rise in the number of malaria cases with the incidence varying from 20 to 90 per 100,000 persons in a population. A study was carried out to describe the distribution of malaria cases in relation to the growing number of foreign workers in Selangor. Data were reviewed using the return forms "PBV (M) 101", a summary of malaria cases in Selangor for 2006 and Annual Reports of Vector-Borne Disease Control Unit, Selangor State Department for 2001- 2005. The malaria cases in Selangor varied between 172 cases in 2001 and 90 cases in 2006. Most of the cases were contributed by foreign workers, who were predominantly male of economically active age group and came from malaria endemic countries. Most of these cases were concentrated in the urban districts. Malaria is still endemic in Selangor. Malarial infection has the potential of contributing to an urban outbreak of malaria.
The purpose of this study was to examine the effect of stimulus sweep direction on the fine structure of the 2f1-f2 distortion product otoacoustic emission (DPOAE). It was hypothesised that the DPOAE fine structure could be shifted if the stimulus sweep changed from one direction to the other. In the present study, ascending, descending and random frequency sweeps were used, with f2 frequency varying between 992 Hz and 2496 Hz and f2/f1 fixed at 1.22. DPOAE fine structure was recorded at 16 Hz intervals. Screening, spontaneous otoacoustic emission (SOAE) and DPOAE measurements were carried out on 19 ears of 19 subjects aged between 22 and 30 years. Data from 14 ears that had at least one significant peak or valley in their DPOAE fine structure were included in the main analysis. Of these, five ears showed at least one occurrence of SOAE over the frequency span 600 Hz to 2500 Hz. Data for ears with and without SOAEs were grouped and analysed separately. The results showed no effect of sweep direction on DPOAE fine structure. No significant differences were observed in peak or valley frequencies, peak height or valley depth between the three stimulus sweep conditions (p > 0.05). There was also no significant effect of stimulus sweep direction on DPOAE level at the point at which SOAE frequency equalled DPOAE frequency (p > 0.05). In conclusion, the study found no effect of stimulus sweep direction on the fine structure of the 2f1-f2 DPOAE, either in ears with or without SOAEs. Therefore, future measurements of this fine structure may use either sweep direction.
Living with borderline personality disorder (BPD) involves a lot of emotional suffering which may be hidden behind the complex and controversial nature of the condition and treatment. The condition is still largely under-diagnosed, undertreated and stigmatized. This paper described the emotional battle faced by a patient living with the disorder and the application of psychosocial treatments in helping her to recover.
In this research wok, three different techniques of change detection were used to detect changes in forest areas. One of the techniques used a local similarity measure approach to detect changes. This new approach of change detection technique, which used mutual information to measure the similarity between two multi-temporal images, was developed based on correspondence of the pixel values, rather than the difference in their intensity. Pixels suffering any changes will be maximally dissimilar. The study was conducted using multi-temporal SPOT 5 satellite images, with the resolution of 10 m x10 m on 5th August 2005 and 13th June 2007. The experimental results show that local mutual information provides more reliable results in detecting changes of the multitemporal images containing different lighting condition compared to the image differencing and NDVI technique, specifically in areas with less plant growth. In addition, it can also overcome the problem on selecting the threshold value. Besides, the findings of this study have also shown that band 3, which is sensitive to vegetation biomass, gave the best result in detecting area of changes compared to the others.
A series of polycrystalline samples (La1-xSmx)0.67Sr0.33MnO3 (X=0.00, 0.05 and 0.10) were prepared using the conventional solid-state reaction method. The XRD analysis indicated that all the samples were fully crystalline and in a single phase with a rhombohedral structure after a sintering at 1200ºC for 24 hours in air. Meanwhile, the Atomic Force Microscopy measurements showed that a small amount of Sm doping in La sites affected the grain growth and this might affect the grain boundary layer, thus resulting in the reduction of the Curie temperature, TC. Extrinsic magnetoresistance (MR) was observed for all the samples with a large negative MR at low field (0-0.1 or 0.2T) region, followed by a slower varying MR at high field (0.1 or 0.2-1T). The highest low-field MR value of -4.6% (at 0.1T) and -6.1% (at 0.2T) were observed for sample X=0.10 and X=0.05, respectively. Hence, these indicated that the extrinsic MR was grain size dependent and was therefore enhanced with a small amount of Sm substitution in La sites.
Studies have been carried out to determine the chemical (soluble solid content) and physical (firmness) parameters of locally grown Cavendish banana by near infrared (NIR) spectroscopy. NIR spectra in the wavelength region of 680-2500 nm were obtained from a total of 408 Cavendish bananas of different ripeness indices. Chemometrics using multiple linear regression (MLR) was applied to develop calibration models for prediction of firmness and soluble solid content (SSC) of Cavendish banana. Results showed that NIR spectroscopy had the feasibility for non-destructive determination of the quality of Cavendish banana. The coefficient of determination (R2) for firmness and SSC calibration models at different ripeness indices ranged from 0.78 to 0.86 and 0.75 to 0.96, respectively. The calibration models were validated using independent sets of data and prediction models developed with the root mean square error of prediction (RMSEP) ranged from 0.01 to 0.26 kgf and 0.039 to 0.788 Brix for firmness and SSC, respectively. The multi-index models showed considerable robustness but higher prediction error with RMSEP of 0.336 kgf for firmness and 0.937% Brix for SSC compared to index specific model.
Bacillus cereus is a soil inhabitant gram positive bacterium, and is known to cause severe food poisoning. The objective of this study was to isolate and identify the presence of Bacillus cereus s.l. from selected ready to eat cereals purchased randomly from local supermarkets in Kuching and Kota Samarahan, Sarawak. The result showed that four of the 30 food samples were detected to be contaminated by B. cereus s.l. . Our findings suggested that it is important for the public to be aware of the safety of RTE cereals consumption, as it is possible that B. cereus s.l. may be present in high count number and pose hazardous health effects to the consumers.