Sel tunggal dan berbilang sel metanol langsung berskala mikro dengan luas permukaan 1.0 cm2 beroperasi secara pasif telah dibangunkan dan diuji. Gas oksigen telah diambil dari persekitaran dan larutan metanol disimpan pada ruang tersedia pada bahagian anod. Prestasi sel tunggal diuji dengan menggunakan beberapa kepekatan metanol antara 1.0 M hingga 5.0 M dan keputusan menunjukkan kepekatan 4.0 M memberikan prestasi yang optimum pada operasi sel. Stek yang mengandungi 6 sel difabrikasi dan diuji dengan menggunakan kepekatan metanol optimum iaitu 4.0 M dan tenaga yang terhasil dengan muatan mangkin yang berbeza pada anod dibandingkan. Kombinasi muatan mangkin 3.0 mg cm-2 Pt/Ru pada anod dan 2.0 mg cm-2 Pt pada katod memberikan nilai tenaga yang paling tinggi antara kombinasi lain iaitu 12.05 mW pada 1.08 V dan 11.2 mA.
The pyroelectric properties of La0.03Sr0.255Ba0.7Nb2-yTiyO(6-y/2) (LSBNT) ceramic pellets using several Ti/Nb ratios sintered at 1250°C for 5 h were investigated. The samples were subjected to several values of electric fields in order to obtain the optimum electric field strength. The pyroelectric coefficients, (p) were measured using the quasi-static method by applying several heating rates. The results show that the Ti/Nb ratios and the dc poling field, (Edc) influenced the measured pyroelectric coefficient of the LSBNT ceramic pellets. The mean grain size of the particles as obtained from scanning electron microscope (SEM) does not seem to give significant impact on the pyroelectric coefficient of the ceramic pellets. However, the X-Ray diffraction (XRD) results indicate that the crystallite sizes of Ti and Nb of these ceramic pellets after being treated with sintering process also influence the measured pyroelectric coefficients of the ceramic pellets.
The effect of copper addition on martensitic structure and reversion from martensite to austenite behaviours upon heating were investigated to clarify mechanism of grain refinement of austenite in Fe-8wt.%Ni-Cu alloys. Upon water-quenching, the alloys underwent a martensitic transformation that exhibited a typical lath-martensitic structure. It was found that prior-austenite grain and martensite-packet sizes were refined with increasing copper content. The grain refinement was not due to a decrease of grain growth rate of the austenite. However, it was found that nucleation rate of the austenite on reversion was increased by the copper addition. In Fe-8wt.%Ni alloy heated in (austenite+ferrite) region, reversed austenite grains were formed at high angle boundaries such as prior austenite grain boundary and packet boundary. On the other hand, TEM observation of the Fe-8wt.%Ni-3wt.%Cu alloy revealed that fine copper particles precipitated within the martensitic structure and the reversed austenite grains also formed within lath-structures and lath boundary. It means that the copper addition promoted formation of the reversed austenite within martensitic matrix and resulted in the grain refinement of the prior-austenite in Fe-8wt.%Ni-Cu alloy.
This study was carried out to investigate the undrained behaviour of weakly bonded soil. Artificial specimens were used and were prepared from a mixture of sand and kaolin. The mixture was fired at 500°C for 5 h to create uniform strength of artificial weakly bonding between sand particles. Based on microscopic observation of the specimens revealed that the fired kaolin formed bridges between the sand particles and most of the sand particles were entirely coated by kaolin. It was observed that very few sand grains made a direct grain to grain contact. The occurrences of inter-particle voids either isolated or connected to form larger voids. Fissures found in between the bonding and the grains were due to high temperature firing. A series of consolidated undrained tests (CU) were performed using conventional triaxial compression test. The stress ratio curves for the bonded specimens showed a significant peak at early strain and the values of maximum stress ratios dropped with increasing applied confining stresses. For the destructured (or unbounded) specimens, no apparent peaks were observed and the stress values were slightly lower compared to that of bonded specimens. The bounding surface for the destructured specimens is represented by a straight line equivalent to stress ratio of 1.24. This line is equivalent to strength parameters of internal friction angle, φ’ and cohesion intercept, c’ of 31o and 21 kPa, respectively. Meanwhile, the bounding surface for the bonded specimens is indicated by some curvature at low stress (p′<150 kPa) and high stresses (p′>1100 kPa). The study clearly suggested the role of bonding on the engineering behaviour of residual soils in undrained conditions.
An electron beam (EB) flue gas test rig and a dielectric barrier discharge (DBD) reactor were tested for the removal of nitric oxide (NO) from gas stream in separate experiments. In both systems, energised electrons were used to produce radicals that reacted with the pollutants. The EB system was a laboratory scale test rig used to treat emission from a diesel run generator. At 1.0 MeV and 10 mA more than 90% NO removal from flue gases flowing at 120 Nm3/h can be achieved. For higher removal percentage, higher beam current was required. In a related effort, a table top, two tubes DBD reactor was used to process bottled gases containing 106 ppm NO. Total removal (>99%) was achieved when the inlet gas contained only NO and N2. Additional SO2 in the in let gas stream lowered the removal rate but was overcame by scaling up the system to 10 DBD tubes. The system was operated with input AC voltage of 35 kV peak to peak. In the EB treatment system, the amount of NO2 increased at high beam current, showing that the NO was also oxidised in the process. Whereas in the DBD reactor, the amount of NO2 remained insignificant throughout the process. This leads to the conclusion that the DBD reactor is capable of producing total removal of NO. This is highly desirable as post treatment will not be necessary.
Titanium dioxide particles were successfully prepared using microemulsion-mediated hydrothermal processing route, with sucrose ester as a stabilising agent. X-ray diffraction patterns revealed that the particles possessed anatase crystal phase. Scanning electron micrographs showed micron-sized spherical particles with rough and smooth surfaces, which eventually interconnected with one another. The formation mechanism of the titanium dioxide microstructures was postulated. The as-prepared particles were subjected to photocatalytic degradation of methylene blue, which exhibited higher photocatalytic activity compared to their commercial counterpart.
The molecular characteristics of sago starch (native and debranched) were determined using a gel permeation chromatograpy multi-angle laser light scattering (GPC-MALLS) method. The method involves the optimisation of sample solubilisation and GPC operating conditions. The weight-average molecular weight Mw of native and debranched sago starch determined was 29.1 ± 2.1 × 106 and 1.87 ± 0.4 × 105 gmol-1 respectively while radius of gyration Rg was 123.6 and 59.3 nm respectively. The reduction in Mw and Rg in debranched sago was attributed to the hydrolysis of α-1,6 glycosidic linkages by pullulanase to smaller oligosaccharides.
An ethanolic solution of caffeine was added to an aqueous solution of metal salts and followed by adding ethanolic solution of adenine and an aqueous solution of potassium thiocyanate to give complexes with general formula [M(CA)2(Ad)X2] where CA is caffeine, Ad is adenine, X is thiocyanate ion and M is Co(II), Ni(II), Cu(II), Zn(II) and Cd(II). The resulting products were characterized using UV-visible and infrared spectroscopies. Elemental analyses were performed using C, H, N analysis and atomic absorption techniques. The magnetic susceptibility and the conductivity were also measured. The results suggested that the complexes have octahedral geometry.
The seed of Jatropha curcas was collected from the outskirts region of the Bardoli (Gujarat) and it was utilized for determination of seed characterization. The Jatropha curcas oil was extracted using light petroleum ether (60-80°C) by Soxhlet apparatus. The physicochemical properties of Jatropha curcas oil were evaluated. The result showed that the seeds consist of 46.31% (dry w/w) oil, moisture and volatilities (5.8% v/w) and protein content (22.50%). The physicochemical properties shows acid value (36.46), iodine value (106.00 mg/g) and saponification value (194.70 mg/g). The unsaponifiable matter was 1.02%. Negative Halphen test indicated the absence of cyclopropanoid acids in seed oil. GC analysis of J. curcas oil showed presence of palmitic acid (16.69%), stearic acid (7.67%), oleic acid (40. 39%) and linoleic acid (33.09%).
This study was carried out in an oil palm plantation in Tanjung Sepat, Selangor in September 2007 by using pigs (Sus scrofa L.) as a carcass model in a forensic entomological research. A 2.5 month old pig (10 kg) which died naturally was hanged on a palm tree to observe the insect succession and decomposition stages. Observation was made for 16 days; one afternoon visit per day and all climatological data were recorded. On the first day, adult muscids of Ophyra spinigera Stein and Musca domestica L. were observed, however no blowfly (Calliphoridae) activities were sighted. Fly eggs wer seen on the second day on both sides of the face, inside nostrils and genitourinary area. Adults of Chrysomya megacephala Fabricius and Chrysomya rufifacies (Macquart) congregated on the head and anal areas. Adult flies and maggots (first and second instars) were observed in the mouth and anus of the pig on the third day of hanging. Adult yellow jackets (Vespidae) and spiders (Arachnida) were found preying on some adult flies. Rove beetles (Staphilinidae) were also discovered on the pig carcass. Only a few ants (Formicidae) were sighted. Maggot masses were found in eye orbits, neck, and genital organs on the fourth day of hanging and some maggots were seen falling down to the ground. The dominant maggot species identified on this day was Ch. megacephala. On the sixth day, the head, neck, and anus were in the stage of active decay. Maggots of Ch. rufifacies were abundant on the seventh day and was the dominant species. On day eight the carcass fell onto the ground. Chrysomya rufifacies maggots were found underneath the pig carcass and they started to migrate and pupated under the soil. On the tenth day, third instar Op. spinigera maggots were found under the carcass. The rate of carcass decomposition slowed down and became stable from tenth day onwards to the sixteenth day of decomposition. Thereafter, most of the remaining parts of the body remained dried and devoid of any insects.
The lichen collection from Bukit Larut, Taiping, Malaysia in 1999 included Bulbothrix isidiza, Chrysothrix xanthina, Cladonia adspersa, C. verticillata, Coccocarpia palmicola, Heterodermia flabellata, H. japonica, H. obscurata, Hypotrachyna imbricatula, Leptogium azureum, Parmelinella wallichiana, Parmotrema tinctorum, P. clavuliferum, P. reticulatum, Pertusaria sp., Physma byrsaeum, Usnea baileyi and Usnea rubrotincta. Secondary metabolites could not be detected in three lichens, Coccocarpia palmicola, Leptogium azureum and Physma byrsaeum by HPLC and TLC analysis. The other 15 lichen species showed the presence of ten classes of compounds, depsides (10 compounds), depsidones (16), quinones (5), xanthones (2), naphthopyrones (1), pulvinic acid derivatives (1), diphenylethers (1), dibenzofurans (1), aliphatic acids (4) and terpenoids (3).
The effects of ammonium tartrate and glucose concentration on biomass, lipid and GLA accumulation in Cunninghamella sp. 2A1 were investigated using Response Surface Methodology (RSM). Cultivation was carried out in 250 mL shake flask containing 100 mL of nitrogen limiting medium (with various combinations of concentration of ammonium tartrate (1-3 g/L) and glucose (30-60 g/L) at 30°C and 250 rpm agitation for 120 h. The concentration of both compounds significantly affected the biomass, lipid and GLA yield (p<0.05), with the production of each of them being represented by quadratic models. Higher concentration of ammonium tartrate and glucose (2.99 and 59.33 g/L, respectively) was required for enhanced biomass production whereas low nitrogen content with excess glucose was otherwise favoured for lipid and GLA production. Ammonium tartrate and glucose concentration at 1 and 43 g/L, respectively were estimated by the model and proven to give the highest lipid production and GLA yield of 31.06 % (g/g biomass) and 4.15 ×10-2 (g/g lipid less biomass), respectively
Growth, mortality and recruitment of the sergestid shrimps Lucifer intermedius, collected from the Sungai Pulai seagrass area in Johor, Peninsular Malaysia was investigated between April 2007 and December 2007 using monthly length-frequency data. The shrimps were collected during the day by subsurface towing of a Bongo net with a mesh size of 500 μm for 30 minutes. Total length was measured monthly for 50 individuals and the estimated extreme length was 10.42 mm. The von Bertalanffy growth parameters, K and L∞ were estimated as 1.40 yr-1 and 11.10 mm, respectively. The growth performance index (φ’) was 2.237 while total mortality (Z) was calculated at 5.32 yr-1. The natural and fishing mortality was 2.99 yr-1 and 2.33 yr-1, respectively. The recruitment pattern of L. intermedius was continuous throughout the year with two major peaks. The exploitation rate (E) was estimated at 0.44. This indicates that fishery status of L. intermedius in the Sungai Pulai sea grass area of Johor Strait is below the optimum level of exploitation (E < 0.50).
Fishes from five streams in Gunung Machinchang and six streams in Gunung Raya areas of Pulau Langkawi were surveyed with the aim to investigate their diversity and distribution. Fish samples were collected from 23rd to 29th November 2007. Samplings took place along the 50 m reach of each of the site using an electrofisher and scoop nets. A total of 619 individuals of fish comprising 27 species and 14 families were recorded. Sixty-six percent from the taxa listed were of the cyprinids and Puntius binotatus was the most abundant species. Carassius auratus auratus was recorded for the first time in Pulau Langkawi. Streams of the Gunung Machinchang area were dominated by secondary freshwater fish species, but in the Gunung Raya area the streams were dominated by primary freshwater fish species. The highest diversity of fish was recorded for Sg. Kubang Badak with Simpson Index Ds = 0.838 and the lowest was for Sg. Perangin with Ds = 0.450. The highest evenness index of fish species was detected for Sg. Temurun with Es = 0.684 and the lowest was for Sg. Perangin with Es = 0.299. Species overlapping between streams of the two areas was 9.6%.
Pertumbuhan sel secara selanjar pada keadaan mantap telah diperolehi dalam pengkulturan dengan bioreaktor padat. Produktiviti (0.02 g/L/j) bioetanol yang paling tinggi diperolehi adalah pada pengudaraan 0.003 vvm. Produktiviti bioetanol didapati meningkat dengan peningkatan kadar pencairan. Produktiviti tertinggi sebanyak 0.037 g/L/j direkod semasa kadar pencairan (D) 0.05 per jam. Penghasilan bioetanol secara selanjar telah berjaya diselenggarakan pada keadaan tidak 100% anaerobik. Pengudaraan yang terbaik untuk produktiviti bioetanol dalam keadaan seimbang pertumbuhan sel dan penghasilan bioetanol ialah pada 0.003 vvm.
Kapsaisinoid merupakan alkaloid yang memberikan ciri kepedasan pada cili serta khusus pada genus Capsicum. Sebatian kapsaisinoid terdiri daripada dua komponen utama iaitu kapsaisin dan dihidrokapsaisin. Dalam kajian ini, pengklonan cDNA Kapsaisin sintase (Cs) telah berjaya dilakukan menerusi kaedah transkripsi berbalik PCR (RT-PCR) dan klon cDNA tersebut dinamakan CUKMCS yang bersaiz 981 pb. Pencarian homologi menggunakan program blastx dan blastp yang terdapat pada pangkalan data NCBI mendapati CUKMCS mempunyai persamaan yang sangat tinggi terhadap Cs pada Capsicum frutescens, Capsicum annuum dan Capsicum chacoense. Saiz ramalan protein CUKMCS diangggarkan sekitar 36 kDa. Penentuan pengekspresan transkrip Cs pada 5 tisu yang berbeza mendapati transkrip dikesan pada tisu plasenta, mesokarp dan biji manakala tiada transkrip Cs dikesan pada daun dan akar
The convergence property for doing logic programming in Hopfield network can be accelerated by using new relaxation method. This paper shows that the performance of the Hopfield network can be improved by using a relaxation rate to control the energy relaxation process. The capacity and performance of these networks is tested by using computer simulations. It was proven by computer simulations that the new approach provides good solutions.
Proses pencecairan lignin soda telah dilakukan dengan menggunakan fenol dengan nisbah 1:3. Proses dilakukan selama 90 minit pada suhu 130oC dalam keadaan refluk. Hasil pencecairan iaitu pemfenolan lignin (PL) telah dianalisis dengan Spektrometer Inframerah Transformasi Fourier (FTIR), reometer dan analisis termogravimetri (TGA). Sampel yang disintesis dengan menggunakan asid hidroklorik sebagai mangkin memberikan keputusan yang terbaik. Analisis FTIR menunjukkan kehadiran kumpulan berfungsi yang signifikan seperti gelang aromatik, alkohol dan karbonil. Kesemua sampel PL mematuhi persamaan Arhenius dan bersifat pseudo-plastik. Peratus kehilangan berat sampel dan kadar penguraian sampel PL dipengaruhi oleh jenis mangkin yang digunakan. Sampel PL yang disintesis dikelaskan sebagai biopolimer resin fenolik.
Potensi 49% poli(metil metakrilat) cangkukan getah asli (MG49) sebagai elektrolit pepejal polimer untuk diaplikasi dalam sistem peranti elektrokimia telah dikaji. Filem MG49 dengan garam LiBF4 sebagai dopan disediakan dengan menggunakan teknik pengacuan larutan. Kekonduksian ion yang diuji dengan menggunakan alat spektroskopi impedans elektrokimia menunjukkan kekonduksian optimum pada penambahan 25% bt garam LiBF4, dengan nilai kekonduksian ion, 1.49×10-9 S.cm-1 pada suhu bilik. Pemerhatian struktur dan morfologi dijalankan dengan menggunakan analisis pembelauan sinar-X dan mikroskopi imbasan elektron. Hasil menunjukkan pengkompleksan dan penghabluran berlaku dalam sistem polimer elektrolit. Hal ini menyebabkan nilai kekonduksian elektrik yang rendah didapati walaupun telah mencapai tahap optimum penambahan garam LiBF4.
Twenty (n=20) beef isolates of Escherichia coli O157:H7 were examined for the detection of Shiga- toxin 1 and 2 (stx1 and stx2) genes by multiplex polymerase chain reaction (PCR) and characterized using Random Amplified Polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR) fingerprinting. All isolates were obtained from the laboratory of Food Science and Biotechnology, University Putra Malaysia, Serdang, Selangor. In the detection of stx1 and stx2 genes, 14 of isolates (14/20) were positive to stx1 and stx2. 5 isolates (5/20) were positive to stx1 and 1 isolate (1/20) was negative by either of stx1 or stx2 genes. Using RAPD-PCR analysis, two oligonucleotides were chosen because they yielded clearly and reproducible band. There were OPAR8 (5’-TGGGGCTGTC-3’) and OPAR20 (5’-ACGGCAAGGA-3’). Subsequently, all 20 isolates of E.coli O157:H7 were subtyped using OPAR8 and OPAR20. Primer OPAR8 produced 8 RAPD-PCR fingerprinting namely P1 to P11. Whereas, OPAR20 produced 16 RAPD-PCR fingerprinting of Q1-Q18. Combination of two primers was analyzed using Unweighted Pair Group Method with Arithmetic mean (UPGMA). Dendogram performed from cluster analysis showed that all the 20 isolates of E.coli O157:H7 differentiated into 20 individual isolates which may suggest the high level of local geographical genetic variation.