Identification of the true statistical distributions for various hydrologic data sets is a major problem facing engineers. The four-parameter kappa distribution is a combination of the established distribution including the Generalised Extreme Value (GEV), Generalised Logistic (GL), Generalised Pareto (GP) and the Gumbel distribution were considered in this study. The main objective of this study was to develop the method of LQ-moments for the kappa distribution. The performance of the LQ-moments was compared with L-moments through eight problems using published data sets. The results showed that the performance of both methods, the LQ-moments and L-moments worked equally well.
The increase in the amount of extracted silicon nanostructures resulting from the incorporation of sodium metasilicon salt in the etching solution was investigated. Silicon nanostructures were prepared in the form of thin fluorescent films via anodisation etching of silicon wafers in aqueous HF/H2O2 solution in the presence of the silicon-based salt. The quality of the fluorescent films was assessed using several nondestructive analytical techniques. The nanostructures produced were then extracted. The harvested nanostuctures were examined for quantitative elemental analysis using atomic absorption spectrophotometry. This investigation was limited to silicon nanostructures with size ≤ 200 nm. The results indicate that the incorporation of the silicate increased the yield of silicon nanostructures production significantly.
Molecularly imprinted polymer (MIP) particles for selective extraction of Pb2+ from aqueous media were prepared using non-covalent molecular imprinting methods. 2-vinylpyridine was chosen as the complexing monomer. The imprinted polymer was synthesised by radical polymerisation. The template (Pb2+) was removed by leaching with 0.1 M HCl. The polymer particles (imprinted and non-imprinted) were characterised by IR spectroscopy. The effect of different parameters such as pH, kinetic, adsorption isotherm and selectivity were evaluated. The maximum adsorption capacity is 150 μg Pb2+/mg MIP. The adsorption efficiently occurred at pH 6. The selectivity coefficients of the imprinted polymer particles for Pb2+/Zn2+ and Pb2+/Al3+ were 13.55 and 1.71, respectively.
Formulation models of brick margarine prepared from the interesterified of a fully hydrogenated palm stearin (POS) and palm kernel oil (PKO), POS of low iodine values and sunflower oil (SFO) were characterised, physically and chemically. Formulations with low trans fatty acid content were used in the margarine preparation and the products were evaluated for 25 days at storage temperatures of 5,10 and 15°C. The study had shown that formulations of POS in the form of simple blend with PKO and SFO (sample 900), blend of interesterified fully hydrogenated POS with PKO and SFO (sample 905) and simple blend of fully hydrogenated POS with PKO and SFO (sample 904) could achieve similar fatty acid composition, but not SFC profile. The results showed that POS was not only a suitable hard stock in trans-free brick margarine formulations but provided functional property in product texture. The formulations, with saturated fatty acid content <36% and <1% trans fatty acid had produced brick margarine with the desired spreadability at refrigerator temperature (5-15°C).
Organomontmorillonites were synthesized by grafting cationic surfactants i.e quaternary ammonium compounds into the interlayer space and were characterized using XRD, FTIR and N2 adsorption/ desorption analysis. The organomontmorillonites were applied as catalyst for the esterification of glycerol (GL) with lauric acid (LA). The catalyst which had symmetrical onium salts (tetrabuthylammoniumbromide, TBAB) gave higher activity than that of unsymmetrical onium salts (cetyltrimethylammoniumbromide, CTAB). Over the TBAB-montmorillonite catalyst, glycerol monolaurate was obtained with a selectivity of about 80%, a lauric acid conversion of about 71% and a glycerol monolaurate yield of about 57%.
Urea complexation is a method favoured by researchers to separate fatty acids based on molecular structure. In this study, effects of urea amount, crystallisation temperature and crystallisation time on the final products of urea complexation were examined. Box-Behnken Design (BBD) was employed to study the significance of these factors and the optimum conditions for the technique were predicted and verified. Results showed that urea-to-polyunsaturated fatty acid (PUFA) mole ratio and crystallisation temperature were two significant variables for enrichment of PUFA in non-urea complexing fraction (NUCF). In a 17-point experimental design, percentage of saturated fatty acid (SFA) was reduced almost entirely from initial 4.49%, monounsaturated fatty acid (MUFA) reduced from 57.02% to 41.32%, while PUFA increased from 33.49% to 53.87% in NUCF. Optimum condition for maximum PUFA and minimum SFA and MUFA contents was predicted at urea-to-PUFA mole ratio of 20, crystallisation temperature of –20°C and crystallisation time of 29.67 h.
Samples of trans-free vegetable ghee were made using palm oil/palm stearin/palm olein (PO/POs/POo) blends (set A) and using palm oil/palm stearin/palm kernel olein (PO/POs/PKOo) blends (set B). Palm stearin of iodine value (IV) 30 was used in this study. The products were evaluated for their physical and chemical properties. Changes in quality during storage were monitored during a period of 16 weeks. Most of the vegetable ghee were granular (grainy) and had a shiny appearance. Chemical analyses indicated that vegetable ghee consisting of PO/POs/POo had higher IV (47.7-52.4) than the PO/POs/PKOo vegetable ghee due to their higher content of unsaturated fatty acids, 46.0-50.0% compared to 36.6-45.0% in Set B. Decreasing the amount of palm oil while increasing palm stearin in the formulations resulted in higher slip melting point (SMP) and higher yield values. Eutectic interaction was noted in PO/POs/PKOo blends. The crystals in samples PO/POs/POo (set A) were predominant in the ß’ polymorphic form. One formulation in set B (B4) exhibited ß crystallinity. Free fatty acids (FFA) were lowest in samples PO/POs/POo 80:5:15 (A4) and PO/POs:/PKOo 80:5:15 (B4) throughout storage. There was no clear trend on anisidine value (AV) while IV remained almost constant. Selected vegetable ghee, A4 wasused to shallow fry roti canai and for cooking nasi minyak. Sensory evaluation on these two products revealed that there was no significant difference (P < 0.05) in texture, taste and overall quality between samples A4 and B4.
The melting and crystallization profile of cocoa butter substitute (CBS) formulation consisting of oil blends between palm mid fraction (PMF) and rice bran oil (RBO) were measured through solid fat content using pulsed Nuclear Magnetic Resonance (pNMR) Bruker Minispe. The isothermal melting and crystallization behaviour were determined via Differential Scanning Calorimeter (DSC). The formulations were developed through binary mixture of palm mid fraction and rice bran oil with different ratios created using Mixture Design, Design Expert version 6.0. Selected formulations had been studied for compositional modification through immobilized lipase catalyzed by interesterification using Novozyme® 435. Three selected parameters such as temperature (40-60°C), catalyst concentration (2-10%) and time (4-48 h) at 200rpm orbital shaking with 14 formulations acquired by applying D-Optimal experimental design had been applied. The results showed that blends of 75% palm mid fraction with 25% rice bran oil and its 14 enzymatic interesterification (EIE) yields have the potential to perform the desired behaviour as the crystals are completely melted at 32.48 - 38.28°C. However, the yields of formulation with EIE condition of 60°C, 10% lipase and 48 h incubation time (labeled N) formed the stable β crystals during tempering as it had melting peak at 34.19°C which was closer to the melting point of cocoa butter required in tempering to form V crystals (~34°C), that assured best chocolate appearance and texture.
Sifat terma dan pembakaran busa poliuretana minyak isirung sawit dan minyak soya dibandingkan. Monoester berkumpulan hujung hidroksil dihasilkan melalui tindak balas minyak isirung sawit (PKO) dan minyak kacang soya (SBO) dengan sebatian polihidrik yang mengandungi dietanolamina/etilena glikol dan mangkin kalium asetat. Tindak balas esterifikasi dan kondensasi ini dijalankan dengan nisbah minyak sayuran kepada sebatian polihidrik adalah 80:20. Monoester ini kemudiannya ditindakbalaskan dengan 2,4-difenilmetana diisosianat untuk menghasilkan poliuretana melalui tindak balas pempolimeran penambahan. Sifat termanya dibandingkan melalui analisis kalorimetri imbasan kebezaan (DSC), analisis termogravimetri (TGA), bom kalorimetri, ujian kestabilan dimensi dan ujian kerintangan api. Busa poliuretana SBO mempunyai nilai entalpi yang rendah daripada busa poliuretana PKO iaitu 7151 kal.g-1 berbanding 7223 kal.g-1 manakala analisis TGA menunjukkan peratus kehilangan jisim busa poliuretana SBO yang rendah (91.0%) berbanding busa poliuretana PKO (92.3%) dengan suhu kestabilan Tstabil adalah masing-masing 196°C dan 198°C. Kadar kebakaran busa poliuretana SBO ialah 0.6-1.2 mm.s-1, rendah daripada kadar kebakaran busa poliuretana PKO iaitu 1.1-1.6 mm.s-1. Menerusi ujian kestabilan dimensi, didapati nilai pengecutan dan pengembangan busa poliuretana SBO adalah kurang daripada busa poliuretana PKO.
Fire-retarding polyurethane (PU) composite was produced by adding 2,4-ditert-butylphenyl phosphite (FR) to palm-based monoester resin with loading percentage of 0, 2, 4, and 6 wt%. The Shore D hardness index increased marginally with increasing FR content. However, the impact and flexural strengths decreased with increasing FR loading attributed to the weak interfacial bonding between FR and PU matrix. The fire test indicated lowering of burning rate (from 5.30 mm.s-1 to 2.80 mm.s-1) as the loading percentage of FR increased. The combustion enthalpy of the composites also decreased with higher loading percentage of FR.
The application of homogenous and heterogeneous catalysts for ethoxylation of lauric acid (LAc) with ethylene oxide (EO) was conducted in this study. Ethoxylation reaction of LAc with EO with the mole ratio 1:3 (LAc:EO) have been done at reaction temperature 130-135°C under 1.8 bar pressure to produce Ethoxylated Lauric Acid (LAc:3EO), a type of nonionic surfactant. This experiment showed that potassium tert-butoxide (tBuOK) as a base homogenous catalyst gave good selectivity and activity compared with potassium methoxide, potassium ethoxide and potassium butoxide. Studies on intercalation of hydrotalcite (HT) with tBuO- to form HTtBuO as solid base catalyst was conducted. Ethoxylation reaction using heterogenous catalyst based on intercalated of HT-tBuO gave lower activity compared with tBuOK as homogenous catalyst. This might be due to diffusion which occurred significantly in heterogenous catalyst compared with homogenous catalyst. Analysis of nonionic surfactant LAc:3EO using HTtBuO as a catalyst gave no undesired side product. Detail analysis of the reaction products using GC-Tof technique gave a mixture of ester of LAc:3EO and polyethylene glycol (PEG).
The scarcity of land based oil reserves has necessitated the exploration of off shore oil. This exploration is often carried out in pristine waters and the use of green chemicals is essential to reduce environmental degradation. In the recovery of oil and gas from rocky formations, well bore fluids such as packer fluids, fracturing fluids, conformance and permeability control fluids are extensively employed. Potassium oleate as viscoelastic surfactants gives a low partition coefficient when in contact with hydrocarbon. Bromination of the oleate chain has been shown in this work to increase the partition coefficient and still maintaining its viscoelasticity. The partition coefficient increased to ca 8% compared to negligible for potassium oleate. A gel was formed when a 20% solution of potasssium 9-bromo stearate was mixed with 8% KCl. Contacting this gel with hydrocarbon resulted in a loss of viscosity due to the improved solubility of the brominated compound in hydrocarbon. This facilitates the removal of the surfactants after its use as a fracturing fluid. The viscoelastic properties were demonstrated using a Bohlin rheometer. The graph of viscosity vs shear rate shows at first a shear rate independence up to a shear rate of 0.2 s-1 and then falling with shear rate typical of a viscoelastic fluid. The zero shear viscosity η0 varied from 18 Pa s to 220 Pa s whilst the shear viscosity at 100 s-1 ranged from 0.16 Pa s to 1.5 Pa s for surfactant concentration from 5 to 20%.
Penggunaan formulasi tablet pelepasan tertahan untuk dadah anti-inflamatori bukan steroid (DAIBS) seperti aspirin berupaya melindungi lapisan perut dari kesan buruk jus asid tubuh. Kajian ini dilakukan untuk menilai keberkesanan formulasi tablet matriks pelepasan tertahan dengan kepelbagaian kepekatan polimer bersama ketoprofen sebagai model. Tablet dibangunkan dengan menggunakan kaedah granulasi basah yang terdiri daripada polimer hidrofilik (hidroksipropil metilselulosa), polimer hidrifobik bersandar pada pH (Eudragit L100-55) dan polimer tak bersandar pada pH (Eudragit R100) sebagai bahan asas pembentukan matriks pada kepekatan 10, 20 dan 30%b/b. Semua formulasi dimampatkan dengan menggunakan mesin pentabletan yang mempunyai penebuk berbentuk cembung bersaiz 10 mm. Tablet yang terhasil diuji daripada segi keseragaman berat, kekerasan, kerapuhan, ketebalan, peratus kandungan dadah dan kajian pelepasan in vitro menggunakan kaedah BP 2007. Hasil menunjukkan kadar pelepasan dadah dikawal oleh jenis dan kepekatan polimer di dalam formulasi matriks. Secara umumnya peningkatan kepekatan kandungan polimer di dalam tablet matriks didapati mengurangkan kadar pelepasan dadah. Perbandingan polimer melalui kepekatan yang sama menggunakan t50%, pula mendapati terdapat perbezaan statistik bermakna (p<0.05) pada kadar pelepasan dadah. Berdasarkan kepada pelepasan dadah dalam kajian in vitro, polimer hidrofobik bersandar pada pH (Eudragit L100-55) menunjukkan profil pelepasan dadah secara tertib sifar yang terbaik berbanding polimer yang lain.
A method for the determination of aflatoxins B1 and B2 in peanuts and corn based products is described. The samples were extracted with a mixture of acetonitrile-water (84:16), followed by multifunctional clean-up and liquid chromatography with fluorescence detection. Both calibration curves showed good correlation from 4.0 to 32.0 ppb for aflatoxin B1 (r=0.9999) and 1.2 to 9.6 ppb for aflatoxin B2 (r=0.9997). The detection limit of aflatoxins B1 and B2 were established at 0.1 and 0.03 ppb, respectively, based on signal-to-noise ratio of 3:1. Average recoveries for the determination of aflatoxins B1 and B2 at 10 and 3 ppb spiking levels, respectively ranged from 94.2 to 107.6%. A total of 20 peanut samples and corn based products were obtained from retail shop and local market around Kuala Terengganu and analyzed for aflatoxins B1 and B2 contents, using the proposed method. Aflatoxins B1 and B2 were detected in 5 out of the 9 peanuts samples and 5 out of the 11 corn based products, at levels ranging from 0.2 to 101.8 ppb.
MeSH terms: Acetonitriles; Aflatoxins; Calibration; Chromatography, Liquid; Zea mays; Fluorescence; Arachis; Water; Aflatoxin B1; Limit of Detection; Signal-To-Noise Ratio
Moisture-dependent physical grain properties of a new registered common bean cultivar ‘Kantar-05’ were determined. Some important chemical parameters of the grain were also investigated. The average length, width and thickness of the grain were 12.48, 7.92 and 5.00 mm at 7.82% db (dry basis) moisture content. The values of bulk density and true density of the grains decreased from 793.37 to 683.62 kg/m3 (P<0.01) and from 1269.37 to 1206.55 kg/m3 (P<0.05) with increasing moisture content. The coefficients of dynamic friction increased from 0.180 to 0.316, 0.173 to 0.276, and 0.226 to 0.331 on steel, plywood and wood friction surface, respectively with increasing moisture content. The force of rupture decreased from 121.88 to 68.93 N with increase in moisture content. Phosphorus, potassium, calcium, sodium and magnesium contents were 5020 ppm, 5576 ppm, 3562 ppm, 780 ppm and 372 ppm, respectively wb% (wet basis) at the initial moisture content. The antioxidant activity and phenolic content of the grains were found to be 56.62% and 24.82 μg GAE/mg db., respectively at the initial moisture content.
Vermicomposting using Lumbricus rubellus was conducted in two different durations, 10 and 30 weeks in the same plots. Three different of treatments combination were prepared with eight replicates for each treatment namely cow dung : kitchen waste in 30:70 ratio (T1), cow dung : coffee grounds in 30:70 ratio (T2), and cow dung : kitchen waste : coffee grounds in 30:35:35 ratio (T3). Macronutrients elements in the vermicompost from each treatment were measured in the tenth and thirtieth week. Comparatively longer duration of vermicomposting by using Lumbricus rubellus enhanced the quality of vermicompost by the increase of the macronutrient elements while reducing the heavy metal concentration and C/N ratio.
The size, growth and age of two congeneric archer fishes Toxotes jaculatrix and Toxotes chatareus collected from Johor coastal waters, Malaysia was studied. The standard length (SL) and body weight (BW) ranges of the two species caught in the study area were 7-12.2 cm SL (9.35±0.19 cm), 11-55 g BW (27.04±1.62 g) and 8-12.2 cm SL (9.88±0.17 cm), 15.12-54 g BW (30.52±1.72 g), respectively. The ratio of male and female specimens of T. jaculatrix and T. chatareus were 70%, 30% and 68.6%, 31.4%, respectively. The estimated von Bertalanffy growth parameters were L∞ = 12.78 cm, 13.59 cm and K = 1.46 year-1, 1.53 year-1 with a growth performance index of Ø’ = 5.48 and 5.64 in both species, respectively. In order to determine the age, the technique of reading and interpretation of the daily growth increments/rings in the sagittae otoliths and scales were applied. Daily growth increments and annulus of scales counts confirmed that the ages of the samples for both species were typically less than one year (<1) and the remnant samples were between one and two years. The similarity between scale and otolith age determination was identical and dissimilarity was observed only in few samples of both species.
Time stepping algorithm with spatial parallelisation is commonly used to solve time dependent partial differential equations. Computation in each time step is carried out using all processors available before sequentially advancing to the next time step. In cases where few spatial components are involved and there are relatively many processors available for use, this will result in fine granularity and decreased scalability. Naturally one alternative is to parallelise the temporal domain. Several time parallelisation algorithms have been suggested for the past two decades. One of them is the pipelined iterations across time steps. In this pipelined time stepping method, communication however is extensive between time steps during the pipelining process. This causes a decrease in performance on distributed memory environment which often has high message latency. We present a modified pipelined time stepping algorithm based on delayed pipelining and reduced communication strategies to improve overall execution time on a distributed memory environment using MPI. Our goal is to reduce the inter-time step communications while providing adequate information for the next time step to converge. Numerical result confirms that the improved algorithm is faster than the original pipelined algorithm and sequential time stepping algorithm with spatial parallelisation alone. The improved algorithm is most beneficial for fine granularity time dependent problems with limited spatial parallelisation.
A map on a group is not necessarily an automorphism on the group. In this paper we determined the necessary and sufficient conditions of a map on a split metacyclic p-group to be an automorphism, where we only considered p as an odd prime number. The metacyclic group can be defined by a presentation and it will be beneficial to have a direct relation between the parameters in the presentation and an automorphism of the group. We considered the action of an automorphism on the generators of the group mentioned. Since any element of a metacyclic group will be mapped to an element of the group by an automorphism, we can conveniently represent the automorphism in a matrix notation. We then used the relations and the regularity of the split metacyclic p-group to find conditions on each entry of the matrix in terms of the parameters in its presentation so that such a matrix does indeed represent an automorphism.
In this research an atomic force microscopy (AFM) study on self-assembled In0.5Ga0.5As/GaAs quantum dots (QDs) was performed. Surface morphology of self-assembled In0.5Ga0.5As QDs changes with different growth time. Increasing growth time increased the dots size and decreased the dots density. In addiditon, self-assembled In0.5Ga0.5As QDs was grown on In0.1Ga0.9As underlying layer with different after-growth AsH3 flow time during cooling-down. The underlying layer caused lattice strain relaxation in the QDs on the surface. Increasing the period of AsH3 flow during cooling-down reduced the diameter of the dots and increased the density. The migration of groups III species in the growth of In0.5Ga0.5As/GaAs system was influenced by AsH3 flow during cooling-down period. This was due to the increase in surface population of active arsenic species. Underlying layer and the period of AsH3 flow during cooling-down are the two key factors in the fabrication of small and dense In0.5Ga0.5As QDs.