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628 results on '"ZAINAL, Z."'

108. Novel pyrochlores in the Bi2O3-Fe2O3-Ta2O5(BFT) ternary system: synthesis, structural and electrical properties

Author

Jusoh, F.A., Tan, K.B., Zainal, Z., Chen, S.K., Khaw, C.C., and Lee, O.J.

Abstract

The purpose of this work is to present a systematic study related to the doping mechanism, structural and electrical properties of the novel pyrochlores in the Bi2O3-Fe2O3-Ta2O5(BFT) system. The pyrochlores with the general formula of Bi3.36Fe2.08+xTa2.56-xO14.56-x(-0.32 ≤ x ≤ 0.48) were prepared through solid-state reaction at 975 °C for 48 h. The subsolidus solution formation involved a mechanism of x Ta5++ x O2−↔ x Fe3+. These phase-pure BFT pyrochlores had a cubic structure with a space group of Fd3m(No. 227), Z = 4. Their lattice parameters were found to vary insignificantly within the range 10.4979 (8)-10.5033 (1) Å. The crystallite sizes determined by Scherrer and Williamson–Hall methods showed a good agreement with their values found to be in the range ∼57−78 nm. Meanwhile, the larger grain sizes in the range 0.2−4.7 μm were measured by the scanning electron microscopy (SEM) analysis. BFT pyrochlores were also found to be high refractory and thermally stable by the thermal analyses. These highly insulating pyrochlores exhibited high activation energies, ∼0.87−1.10 eV; moderate high dielectric constants, ∼78–92 and dielectric losses, ∼10-1at 1 MHz and ∼30 °C. As such, these dielectric materials could be attractive candidates for potential application in low temperature co-fired ceramic (LTCC).

Published
2020
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109. Influence of deposition time on the surface morphology and photoelectrochemical properties of copper doped titania nanotubes prepared by electrodeposition.

Author

Mahmud, M. A., Chin, L. Y., Khusaimi, Z., Zainal, Z., Mahmood, Mohamad Rusop, Soga, Tetsuo, Nagaoka, Shiro, Mamat, Mohamad Hafiz, and Jafar, Salifairus Mohammad

Subjects
PHOTOELECTROCHEMISTRY, COPPER alloys, DOPING agents (Chemistry), ELECTROFORMING, SOL-gel processes
Abstract

A great attention has focused on Cu doped titania nanotubes (Cu/TiNT) as a versatile advance material since it can be employed in various promising technological applications. The current study reported on the influence of various deposition times on the surface morphology and photoelectrochemical properties of Cu/TiNT via electrodeposition technique. Cu loaded on the TiNT surface was detected with prolonged deposition time. For photoelectrochemical (PEC) measurement, the highest responsive photocurrent density was obtained at 20 minutes with 54.3 µA/cm2. Too long duration (40 mins) resulted in poor performance of Cu/TiNT as only 22.6 µA/cm2 of photocurrent being generated. [ABSTRACT FROM AUTHOR]

Published
2018
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115. Batch isotherm and thermodynamic studies of pineapple (Ananas comosus) plant stem as agricultural biosorbent for the removal of Basic Blue 3 and Congo Red dyes

Author

Chan, Siew Ling, Tan, Yen Ping, Abdullah, Abdul Halim, Ong, Siew Teng, Zainal, Z., Yusof, N. A., Chan, Siew Ling, Tan, Yen Ping, Abdullah, Abdul Halim, Ong, Siew Teng, Zainal, Z., and Yusof, N. A.

Abstract

There are considerable amount of dyes to be discharged in the effluent from dyeing and finishing processes in the textile industry. The discharged dyes are known to be toxic, carcinogenic and mutagenic toward the aquatic system. A low concentration of dyes in the effluent can affect the aesthetic and transparency of water stream. Remaining dyes in the effluent necessitated colour removal along with the stringent restrictions and regulations established. Agricultural waste generally is preferred due to its cost-effective and good performance in adsorption. Pineapple plant stem (PPS) is one of the agricultural residues after shoots transplantation. Utilisation of PPS in dyes removal not only can remediate textile wastewater but also reduce the agricultural waste management problem in Malaysia. In the present study, the performance of pineapple plant stem for cationic (Basic Blue 3, BB3) and anionic (Congo Red, CR) dyes removal has been evaluated in a batch process. The isotherm equilibrium studies indicated that BB3 could be well described by Freundlich model (R² = 0.999) while high correlation values of CR obtained from Langmuir (R² = 0.999) and Temkin (R² = 0.997) models. The maximum sorption capacities for BB3 and CR were found to be 59.52 and 11.92 mg g¯¹, respectively under a favourable sorption process. The dependency of BB3 and CR adsorption on temperature was validated by van’t Hoff equation. The effect of temperature on the BB3 and CR removal by PPS was ascertained by studying the temperature-dependence dyes distribution between bulk solution and adsorbent, and the interaction between dyes and adsorbent. Removal of BB3 and CR by PPS was found to be exothermic. The result suggests that PPS has higher affinity on cationic than anionic dye.

Published
2015

118. The fate of SOFC anodes under biomass producer gas contaminants.

Author

Din, Zia Ud and Zainal, Z. A.

Subjects
*SOLID oxide fuel cells, *ANODES, *BIOMASS gasification, *POLLUTANTS, *GAS cleaning
Abstract

Biomass gasification integrated with Solid Oxide Fuel Cells (SOFCs) offers a tremendous opportunity to generate highly efficient power in sustainable and environmental friendly manner. The comprehensive survey of the up-to-date literature on the influence of producer gas contaminants (particulates, alkali metals, tar, H2S and HCl) on SOFC anodes presented in this review reveals that state-of-the-art Ni/YSZ anodes are less tolerant to the contaminants and more stringent cleaning is required for them as compared to Ni/GDC anodes, while other anodes have been scarcely studied. The most striking finding is that Ni/GDC anodes seem to be rather more tolerant to the contaminants as recently understood. This remarkable opportunity needs to be further explored via detailed experiments which would lead to design the economically viable gas cleaning systems. The available gas cleaning technologies are also analysed and the most suitable cleaning options for each of the contaminant are suggested. [ABSTRACT FROM AUTHOR]

Published
2017
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121. Developmental abnormalities and reduced fruit softening in\ud tomato plants expressing an antisense rab11 GTPase gene

Author

Lu, C, Zainal, Z, Tucker, GA, and Lycett, GW

Subjects
food and beverages
Abstract

A cDNA clone from tomato fruit encodes a protein with strong homology with the rab11/YPT3 class of small GTPases that is thought to be involved in the control of protein trafficking within cells. The gene, LeRab11a, showed a pattern consistent with a single copy in DNA gel blots. The corresponding mRNA was developmentally regulated during fruit ripening, and its expression was inhibited in several ripening mutants. Its reduced expression in the Never-ripe mutant indicates that it may be induced by ethylene in fruit. The ripening-induced expression in tissues that are undergoing cell wall loosening immediately suggests a possible role in trafficking of cell wall–modifying enzymes. The message\ud also was produced in leaves and flowers but not in roots. Antisense transformation was used to generate a “mutant\ud phenotype.” Antisense fruit changed color as expected but failed to soften normally. This was accompanied by reduced levels of two cell wall hydrolases, pectinesterase and polygalacturonase. There were other phenotypic effects in the plants, including determinate growth, reduced apical dominance, branched inflorescences, abnormal floral structure, and ectopic shoots on the leaves. In some plants, ethylene production was reduced. These data suggest an alternative or additional role in exocytosis or endocytosis of homeotic proteins, hormone carriers, or receptors.

Published
2001

122. High temperature impedance spectroscopy study of non-stoichiometric bismuth zinc niobate pyrochlore.

Author

Tan, Kar Ban, Khaw, C. C., Lee, C. K., Zainal, Z., Tan, Y. P., Shaari, Hasnizam, Tan, Kar Ban, Khaw, C. C., Lee, C. K., Zainal, Z., Tan, Y. P., and Shaari, Hasnizam

Abstract

Single phase non-stoichiometric bismuth zinc niobate, Bi3Zn1.84Nb3O13.84, was fabricated by a conventional solid state method. The sample was refined and fully indexed on the cubic system, space group Fd3m (No. 227), Z = 4 with a = 10.5579(4) �. Electrical characterisation was performed using an ac impedance analyser over the temperature range of 25-850 �C and frequency range of 5 Hz-13 MHz. Typical dielectric response is observed in Bi3 Zn1.84Nb3O13.84 with a high relative permittivity, low dielectric loss and a negative temperature coefficient of capacitance, with the values of 147, 0.002 and -396 ppm/�C, at 100 kHz at ambient temperature, respectively. This material is highly resistive, with a conductivity of 1�10-21 O-1�cm-1 and a high activation energy of ca. 1.59 eV.

Published
2009

124. First distribution records of Acetes intermedius (Decapoda: Sergestidae)from the coastal waters of Bintulu, Sarawak : population structure, length-weigh and length-length relationship.

Author

S. M., Nurul Amin, Aziz, Arshad, Zainal, Z., Idris, Mohd Hanafi, Siraj, Siti Shapor, Sidik Bujang, Japar, S. M., Nurul Amin, Aziz, Arshad, Zainal, Z., Idris, Mohd Hanafi, Siraj, Siti Shapor, and Sidik Bujang, Japar

Abstract

Sergestid shrimp Acetes intermedius was recorded for the first time from the Bintulu coastal waters in Sarawak. The morphological characters of the species were examined. Population structure, length-weight and length-length relationship of A. intermedius was estimated based on specimens collected from the site during February-March 2006. A total of 857 specimens (473 males and 384 females) of A. intermedius were measured for the study of size frequency structure. The mean length of the male and female was 25.6 ± 2.52 mm and 27.02 ± 3.24 mm, respectively. The sex ratio was found to be 1: 0.81 (males: females). Total length of female was on an average 1.41 mm longer than the male (P < 0.01). The equations calculated for length-weight relationship were W = 0.0025 TL3.1484 (r2 = 0.80) for male, W = 0.0033 L3.044 (r2 = 0.77) for female. The value of b for males (b = 3.148) and females (b = 3.044) were closest to 3 which was not significantly higher than isometric value (3) indicating that the growth in males and females were isometric. The estimated co efficient of correlation (r) between the total length and body weight was 0.99 for combined sexes of the species, indicating that the relationship was highly significant (P < 0.01).

Published
2008

146. Efficient plant regeneration of Malaysian aromatic rice (Oryza sativa L.) through somatic embryogenesis.

Author

Rahman, Z. A., Ramli, A., Hosni, H., Kamaruzaman, R., Seman, Z. A., Othman, A. N., Zainal, Z., Uddain, J., and Subramaniam, S.

Subjects
PLANT growth, PLANT cell culture, RICE varieties, REGENERATION (Botany), SOMATIC embryogenesis
Abstract

Aromatic rice variety namely MRQ 74, MRQ 80 and MRQ 50 are the most popular rice in Malaysia. Establishing an efficient regeneration protocols via somatic embryogenesis is required for varietal improvements. An efficient somatic embryogenesis system has been established for three aromatic rice varieties using mature seeds. MS-B5 medium containing 1 mg/L 2, 4-D (2, 4-dichlorophenoxyacetic acid) and 10 mg/L NAA (á-naphthaleneacetic acid) optimized that produced highest embryogenic callus (89%) without any browning effect. The highest whitish somatic embryos frequency (75%) was initiated by incubating embryogenic calli on same medium containing 10 mg/L ABA and 9 g/L Gelrite for 8 weeks. However, the numbers of regenerated plantlets on medium containing NAA and 2,4-D which was previously pre-treated with 10 mg/L ABA, 9 g/L Gelrite and incubation at 8 weeks was the best method for shoots induction of three rice varieties. [ABSTRACT FROM AUTHOR]

Published
2015
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147. Supercritical water gasification of empty fruit bunches from oil palm for hydrogen production.

Author

Sivasangar, S., Zainal, Z., Salmiaton, A., and Taufiq-Yap, Y.H.

Subjects
*OIL gasification, *HYDROGEN production, *SUPERCRITICAL water, *OIL palm, *PLANTATIONS, *AGRICULTURAL wastes
Abstract

Empty fruit bunches (EFBs) from the palm plantation sector are abundant agricultural waste products in Malaysia. Supercritical water gasification (SCWG) is a prominent way to convert high-moisture-content biomass such as EFBs into valuable end products. This investigation is focused on EFB conversion into hydrogen-rich products using SCWG (temperature = 380 °C and pressure ≈ 240 bar). Lignocellulosic model compounds (xylan, cellulose, and lignin) were used to study the degradation patterns and gas compositions under similar reaction conditions. The effect of the EFB/water ratio and the SCWG reaction time on the composition of the product gas was examined. Carbon gasification does not improve with increasing EFB/water ratio as well as with increasing reaction time caused by the thermally stable tar formation during reaction. The hydrogen concentration was found to be increased with reaction time along with raising the EFB/water ratio to 0.3 g (3.75 wt%). In addition, the possibility of using palm oil mill effluent as a reaction medium in comparison to deionized water was analyzed. [ABSTRACT FROM AUTHOR]

Published
2015
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