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排序方式: 共有791条查询结果,搜索用时 15 毫秒
71.
Elham Moazami Farahany Jinap Selamat Yakoob Bin Che Man Nor Aini Idris 《International Journal of Food Science & Technology》2008,43(6):1083-1087
The tocopherol and tocotrienol compositions of the genuine cocoa butter (CB) and palm mid‐fraction (PMF) were investigated to introduce a more reliable indicator in detecting PMF in CB. The results suggested that the α‐tocotrienol data presented could be utilised for the detection of the PMF admixture to CB. The PMF was added to CB at different levels. HPLC was used to detect the presence of PMF admixture to CB using α‐tocotrienol as an indicator. The results derived from the model system indicated that increasing the PMF amount at 0–15% to CB resulted in an increase in the concentration of the α‐tocotrienol significantly (P < 0.05). The addition of PMF amount more than 15% did not have any effect on the α‐tocotrienol concentration. A linear plot with a high correlation of 0.9967 was obtained with SE of 1.527. The high correlation obtained indicated good accuracy, reflecting a close relationship between experimental and theoretical predicted value. 相似文献
72.
73.
Study of morphology and gas separation properties of polysulfone/titanium dioxide mixed matrix membranes
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Pourya Moradihamedani Nor Azowa Ibrahim Wan Md Zin Wan Yunus Nor Azah Yusof 《Polymer Engineering and Science》2015,55(2):367-374
Polysulfone (PSf)‐based mixed matrix membranes (MMMs) with the incorporation of titanium dioxide (TiO2) nanoparticles were prepared. Distribution and agglomeration of TiO2 in polymer matrix and also surface of membranes were observed by scanning electron microscopy, transmission electron microscopy, and energy dispersive X‐ray. Variation in surface roughness of MMMs with different TiO2 loadings was analyzed by atomic force microscopy. Physical properties of membranes before and after cross‐linking were identified through thermal gravimetric analysis. At low TiO2 loadings (≤3 wt%), both CO2 and CH4 permeabilities decreased and consequently gas selectivity improved and reached to 36.5 at 3 bar pressure. Interestingly, PSf/TiO2 3 wt% membrane did not allow to CH4 molecules to pass through the membrane and this sample just had CO2 permeability at 1 bar pressure. Gas permeability increased considerably at high filler contents (≥5 wt%) and CO2 permeance reached to 37.7 GPU for PSf/TiO2 7 wt% at 7 bar pressure. It was detected that, critical nanoparticle aggregation has occurred at higher filler loadings (≥5 wt%), which contributed to formation of macrovoids and defects in MMMs. Accordingly, MMMs with higher gas permeance and lower gas selectivity were prepared in higher TiO2 contents (≥5 wt%). POLYM. ENG. SCI., 55:367–374, 2015. © 2014 Society of Plastics Engineers 相似文献
74.
Oi Wei Mak Nursyafikah Seman Nor Hamizah Harun Rusnah Syahila Duali Hussen Nasrulzamani Mohd Rodzi Thorsten Heidelberg 《Journal of surfactants and detergents》2015,18(6):973-980
A biantennary surfactant based on a synthetic C16‐maltoside was chosen to prepare vesicles for a potential vesicular drug delivery system. The synthesis comprised of three stages: Initial synthesis of β‐d ‐maltose octaacetate was followed by glycosidation of 2‐hexyl‐decanol and final glycolipid deacetylation. Both α‐ and β‐anomers were prepared and their anomeric purity was evaluated by 1H NMR. Owing to the low water solubility of the glycolipid, addition of ionic co‐surfactants was believed to promote the surfactant distribution, thus leading to smaller and more uniform vesicles. The assembly behavior of the surfactant systems was studied by contact penetration under an optical polarizing microscope, while interfacial properties were determined by surface tension measurements. Vesicles were prepared by injection of an ethanolic solution into bulk water and investigated by dynamic light scattering and field emission scanning electron microscopy. Contact of the surfactant mixtures with water indicated a high tendency to exhibit the lamellar phase and confirmed the expected low molecular solubility. These findings suggest a potential of the surfactant to form stable vesicles. Injection of an ethanolic surfactant solution into bulk water gave sub‐micrometer sized vesicles with a narrow size distribution. Application of ionic co‐surfactants reduced the vesicle size. In particular ~20 % of anionic SDS proved highly effective, lowering the vesicle size by nearly one decade, thus accessing nano‐sized vesicles. Encapsulation of a water‐soluble drug was achieved in a 76 ± 10 % efficiency. 相似文献
75.
Wardah Fatimah Mohammad Yusoff Elias Salleh Nor Mariah Adam Abdul Razak Sapian Mohamad Yusof Sulaiman 《Building and Environment》2010
In the hot and humid climate, stack ventilation is inefficient due to small temperature difference between the inside and outside of naturally ventilated buildings. Hence, solar induced ventilation is a feasible alternative in enhancing the stack ventilation. This paper aims to investigate the effectiveness of a proposed solar induced ventilation strategy, which combines a roof solar collector and a vertical stack, in enhancing the stack ventilation performance in the hot and humid climate. The methodology selected for the investigation is physical experimental modelling which was carried out in the actual environment. The results are presented and discussed in terms of two performance variables: air temperature and air velocity. The findings indicate that the proposed strategy is able to enhance the stack ventilation, both in semi-clear sky and overcast sky conditions. The highest air temperature difference between the air inside the stack and the ambient air (Ti−To) is achieved in the semi-clear sky condition, which is about 9.9 °C (45.8 °C–35.9 °C). Meanwhile, in the overcast sky condition, the highest air temperature difference (Ti−To) is 6.2 °C (39.3 °C–33.1 °C). The experimental results also indicate good agreement with the theoretical results for the glass temperature, the air temperature in the roof solar collector’s channel and the absorber temperature. The findings also show that wind has significant effect to the induced air velocity by the proposed strategy. 相似文献
76.
Ştefan Ţălu Samah Boudour Idris Bouchama Bandar Astinchap Hamta Ghanbaripour Muhammad Saeed Akhtar Sarwat Zahra 《Microscopy research and technique》2022,85(4):1213-1223
A multifractal analysis has been performed on the 3D (three-dimensional) surface microtexture of magnesium-doped zinc oxide (ZnO:Mg) thin films with doping concentration of 0, 2, 4, and 5%. Thin films were deposited onto the glass substrates via the sol–gel spin coating method. The effect of magnesium doping, on the crystal structure, morphology, and band gap for ZnO:Mg thin films has been analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and UV–Vis spectroscopy. It has been observed that the surface of ZnO thin films is multifractal in nature. However, multifractality and complexity observed to decrease with increasing content of Mg in ZnO thin films due to formation of islands on the surface in accordance with Volmer–Weber growth mechanism. The investigations revealed that crystallinity, microtexture, morphology, and optical properties of the thin films can be tuned by controlling the Mg content within the ZnO lattice. In particular, their optical band gap energies were 3.27, 3.31, 3.34, and 3.33 eV at 0, 2, 4, and 5%, respectively. The prepared thin films of ZnO:Mg with tuned characteristics would have promising applications in optoelectronic devices. 相似文献
77.
In the present paper, the effects of ethanol as a gasoline additive and water as a contaminant on the corrosion behavior of metallic components of a fuel delivery system were investigated. Electrochemical impedance spectroscopy (EIS) testing was performed in both water-free and water contaminated gasoline containing 0%, 5%, 10% and 15% ethanol without the addition of any supporting electrolyte. The surface of the specimens examined in 10% ethanol blended gasoline was observed by scanning electron microscope to understand what types of corrosion attack occurred. The results revealed that the addition of ethanol to gasoline fuel decreased the solution resistance and polarization resistance values of the specimens, resulting in an increase in the corrosion rates of these specimens in ethanol blended gasoline. Water contaminant caused a decrease in the polarization resistance of the ferrous specimens, whereas the observed behavior in others was reversed. Among the investigated metallic materials, the brazing alloy fared the best while Al 6061 alloy showed satisfactory corrosion resistance compared to the rest of the materials in both water-free and water-contaminated ethanol blended gasoline. Moreover, no localized attack was observed in corrosion products. 相似文献
78.
Synthesis and characterization of waterborne and phosphorus-containing flame retardant polyurethane coatings 总被引:2,自引:0,他引:2
Funda ?elebi Leyla Aras Güng?r Gündüz Idris M. Akhmedov 《Journal of Coatings Technology》2003,75(944):65-71
Phosphorus-containing flame retardant water-dispersed polyurethane coatings were produced by incorporating different amounts
of a phosphorus compound onto the polyurethane main chain. The novel phosphorus containing compound (phosphorus phenyl dihydroxy)
was synthesized in three steps using benzaldehyde, pentaerythritol, phenyl phosphonic dichloride, and acetic acid.
The addition of phosphorus phenyl dihydroxy to the main chain of polyurethane, in which NCO/OH ratio was kept constant at
1.5 and the amount of dimethylolpropionic acid (DMPA) at 3.5 wt%, increased the hardness and abrasion resistance, but only
slightly decreased the gloss values of the polyurethane paints. All the samples showed superior impact resistance and flexibility.
Moreover, increasing the phosphorus content increased the char yield, and the maximum fire retardancy was reached at 1.5%
P content with a limiting oxygen index (LOI) value of 29.
Kimya B?lümü, 06531 Ankara, Turkey. 相似文献
79.
Lalchand A Patil Dinesh N Suryawanshi Idris G Pathan Dhanashri G Patil 《Bulletin of Materials Science》2014,37(3):425-432
Nanostructured pure and Pt-doped TiO2 thin films were prepared by chemical spray pyrolysis technique. Aqueous solution of TiCl3·6H2O (0·01 M) was chosen as the starting solution for the preparation of pure TiO2 thin film. Aqueous solutions of PtCl6·6H2O (0·01 M) and TiCl3·6H2O (0·01 M) were mixed in volume % of 1 : 99, 2·5 : 97·5 and 5 : 95 respectively to obtain Pt-doped TiO2 thin films. The solutions were sprayed onto quartz substrate heated at 350 °C temperature to obtain the films. These thin films were fired for one hour at 550 °C. The sensing performance of these films was tested for various gases such as LPG, H2, CO2, ethanol, NH3 and Cl2 (1000 ppm). The Pt-doped TiO2 (1 : 99) was observed to be most sensitive (572) to H2 at 400 °C with high selectivity against other gases. Its response time was short (10 s) and recovery was also fast (14 s). To understand the reasons behind the gas-sensing performance of the films, their structural and microstructral properties were studied using X-ray diffraction and electron microscopy (FE–SEM and TEM), respectively. Thicknesses of all these samples were determined using Surface Profiler. The results are interpreted. 相似文献
80.
Hamidreza Ghandvar Saeed Farahany Jamaliah Idris 《Materials and Manufacturing Processes》2015,30(12):1442-1449
The effects of SiCp treatment and magnesium addition on microstructural and mechanical properties of Al356/20 wt% SiCp semisolid composites were investigated. The results showed that cleaning and oxidizing of SiCp and addition of 1 wt% Mg resulted in improving wettability, incorporation, and uniform distribution of SiCp in A356 matrix. Consequently, the ultimate tensile strength (UTS) value increased by 19% and 32% when the SiC was treated and also when Mg was added, respectively, compared to as-received SiCp. In addition, hardness value increased from 69.7 HV in as-received SiCp to 94.8 HV after SiCp treatment and addition of Mg. 相似文献