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71.
Multimedia Tools and Applications - Nowadays, digital protection has become greater prominence for daily digital activities. It’s far vital for people to keep new passwords in their minds and... 相似文献
72.
The rheological behavior of coir‐fiber‐filled polypropylene (PP) composite has been studied at constant shear stress. The shear stress versus shear rate relationship for the composite follows power law model of viscous flow. Unlike similar studies in the literature, the viscosity is treated as a stress‐independent parameter, which increases with the increase of fiber loading; but decreases with the rise of temperature. The SEM reveals that the fibers are loosely bound to the polymer matrix and the outer surface of the composite is rough and irregular, making it susceptible to high friction with the wall of the flow channel. With analogy to nth order chemical reaction, new formula has been derived for the activation energy of viscous flow, which is found to increase with the increase in the fiber content. The die‐swell ratio decreases with the increase of fiber loading, but increases with the rise of temperature. The elastics parameters of the composite such as the recoverable shear strain, the first normal stress difference, and the elastic strain induced by the stored energy in the capillary reservoir have been estimated based on the die‐swell data. POLYM. COMPOS., 36:51–61, 2015. © 2014 Society of Plastics Engineers 相似文献
73.
In modern structural constructions, concrete-filled steel tubular (CFT) columns have gradually become a central element in structural systems like tall buildings, bridges and so forth. The effective parameters on load carrying capacity of CFT columns are the bond between the steel and internal concrete, local buckling strength of steel tube, creep of concrete and loading conditions of column at connections. Considering these effective parameters, a novel section is suggested which can be used for columns of tall buildings and bridges with large spans. The main characteristic of the suggested steel section is internal longitudinal symmetric stiffeners. In the present study, a comparative investigation into the behavior of this novel section (with circular and octagonal shapes) and the most common used sections of CFT columns has been carried out under axial and cyclic loading. Having verified the finite element modeling, several different analyses have been undertaken. The results of the analyses clearly exhibit the increase in strength and ductility of the suggested novel section under axial and cyclic loading and therefore, its application is recommended in construction practice. 相似文献
74.
Tolga Tavsanoglu Ceren Begum Murat Alkan Onuralp Yucel 《JOM Journal of the Minerals, Metals and Materials Society》2013,65(4):562-566
In this study, WC (tungsten carbide) thin films were deposited on high-speed steel (AISI M2) and Si (100) substrates by direct current magnetron sputtering of a tungsten carbide target having 7% cobalt as binding material. The properties of the coatings have been modified by the change in the bias voltages from grounded to 200 V. All the coatings were deposited at 250°C constant temperature. The microstructure and the thickness of the films were determined from cross-sectional field-emission gun scanning electron microscope micrographs. The chemical composition of the film was determined by electron probe micro analyzer. The x-ray diffractometer has been used for the phase analyses. Nanoindentation and wear tests were used to determine the mechanical and tribological properties of the films, respectively. It is found that the increase in the bias voltages increased drastically the hardness and elastic modulus, decreased the friction coefficient values and increased the wear resistance of tungsten carbide thin films by a phase transformation from metallic W (tungsten) to a nonstoichiometric WC1?x (tungsten carbide) phase. 相似文献
75.
Hiroshi Hasegawa Ismail M.M. Rahman Masayoshi NakanoZinnat A. Begum Yuji EgawaTeruya Maki Yoshiaki FurushoSatoshi Mizutani 《Water research》2011,45(16):4844-4854
Aminopolycarboxylate chelants (APCs) are extremely useful for a variety of industrial applications, including the treatment of toxic metal-contaminated solid waste materials. Because non-toxic matrix elements compete with toxic metals for the binding sites of APCs, an excess of chelant is commonly added to ensure the adequate sequestration of toxic metal contaminants during waste treatment operations. The major environmental impacts of APCs are related to their ability to solubilize toxic heavy metals. If APCs are not sufficiently eliminated from the effluent, the aqueous transport of metals can occur through the introduction of APCs into the natural environment, increasing the magnitude of associated toxicity. Although several techniques that focus primarily on the degradation of APCs at the pre-release step have been proposed, methods that recycle not only the processed water, but also provide the option to recover and reuse the metals, might be economically feasible, considering the high costs involved due to the chelants used in metal ion sequestration. In this paper, we propose a separation process for the recovery of metals from effluents that contain an excess of APCs. Additionally, the option of recycling the processed water using a solid phase extraction (SPE) system with an ion-selective immobilized macrocyclic material, commonly known as a molecular recognition technology (MRT) gel, is presented. Simulated effluents containing As(V), Cd(II), Cr(III), Pb(II) or Se(IV) in the presence of APCs at molar ratios of 1:50 in H2O were studied with a flow rate of 0.2 mL min−1. The ‘captured’ ions in the SPE system were quantitatively eluted with HNO3. The effects of solution pH, metal-chelant stability constants and matrix elements were assessed. Better separation performance for the metals was achieved with the MRT-SPE compared to other SPE materials. Our proposed technique offers the advantage of a non-destructive separation of both metal ions and chelants compared to conventional treatment options for such effluents. 相似文献
76.
Md. Tariqul Islam Shajib Mahbuba Kawser Md. Nuruddin Miah Parveen Begum Lalita Bhattacharjee A. Hossain Inge S. Fomsgaard Sheikh Nazrul Islam 《Food chemistry》2013
In line of the development of a food composition database for Bangladesh, 10 minor indigenous fruits were analysed for their nutrient composition comprising ascorbic acid, carotenoids and mineral values. Nutrient data obtained have been compared with published data reported in different literatures, book and United States Department of Agriculture-National Nutrient Database for Standard Reference. Ascorbic acid was highest in Wood apple and lowest in Roselle. Monkey jack contained the highest amount of carotenoids, zinc and copper. Content of calcium, magnesium and phosphorous were found highest in Antidesma velutinum. Potassium was the highest in Wood apple followed by in Moneky jack. It was noted that most of the minor fruits have much higher amount of ascorbic acid than the national fruit – Jack fruit ripe, the king fruit – Mango ripe of Bangladesh and exotic fruits – Apple and Grapes. The nutrient values of these minor fruits would make awareness among the people for their mass consumption for healthy life and to grow more minor fruit trees from extinction in order to maintain biodiversity. 相似文献
77.
Thatchawan Thanasupawat Aleksandra Glogowska Christopher Pascoe Sai Nivedita Krishnan Maliha Munir Farhana Begum Jason Beiko Jerry Krcek Marc R. Del Bigio Marshall Pitz Yaoqing Shen Victor Spicer Kevin M. Coombs John Wilkins Sabine Hombach-Klonisch Thomas Klonisch 《International journal of molecular sciences》2021,22(17)
Malignant gliomas derive from brain glial cells and represent >75% of primary brain tumors. This includes anaplastic astrocytoma (grade III; AS), the most common and fatal glioblastoma multiforme (grade IV; GBM), and oligodendroglioma (ODG). We have generated patient-derived AS, GBM, and ODG cell models to study disease mechanisms and test patient-centered therapeutic strategies. We have used an aptamer-based high-throughput SOMAscan® 1.3K assay to determine the proteomic profiles of 1307 different analytes. SOMAscan® proteomes of AS and GBM self-organized into closely adjacent proteomes which were clearly distinct from ODG proteomes. GBM self-organized into four proteomic clusters of which SOMAscan® cluster 4 proteome predicted a highly inter-connected proteomic network. Several up- and down-regulated proteins relevant to glioma were successfully validated in GBM cell isolates across different SOMAscan® clusters and in corresponding GBM tissues. Slow off-rate modified aptamer proteomics is an attractive analytical tool for rapid proteomic stratification of different malignant gliomas and identified cluster-specific SOMAscan® signatures and functionalities in patient GBM cells. 相似文献
78.
Hasina Begum Sanjoy Banerjee Helena Khatoon Mohamed Shariff 《Critical reviews in food science and nutrition》2016,56(13):2209-2222
Microalgae are the major photosynthesizers on earth and produce important pigments that include chlorophyll a, b and c, β-carotene, astaxanthin, xanthophylls, and phycobiliproteins. Presently, synthetic colorants are used in food, cosmetic, nutraceutical, and pharmaceutical industries. However, due to problems associated with the harmful effects of synthetic colorants, exploitation of microalgal pigments as a source of natural colors becomes an attractive option. There are various factors such as nutrient availability, salinity, pH, temperature, light wavelength, and light intensity that affect pigment production in microalgae. This paper reviews the availability and characteristics of microalgal pigments, factors affecting pigment production, and the application of pigments produced from microalgae. The potential of microalgal pigments as a source of natural colors is enormous as an alternative to synthetic coloring agents, which has limited applications due to regulatory practice for health reasons. 相似文献
79.
Saba Gul Mushtaq Ahmad Muhammad Zafar Saraj Bahadur Ferhat Celep Shazia Sultana Najla Begum Uzma Hanif Wajid Zaman Muhammad Shuaib Asma Ayaz 《Microscopy research and technique》2019,82(9):1507-1528
Foliar micromorphological features are useful to elucidate the taxonomy and systematics of the Lamiaceae species. Leaf epidermal morphology using scanning electron microscopy and light microscopy of 22 Lamiaceae species from 15 genera have been investigated with an aim to solve its taxonomic problem in the correct identification. Various foliar micromorphological features were observed to explain their importance in resolving the correct identification of Lamiaceae taxa. Two main types of trichomes were observed; glandular trichomes (GTs) and nonglandular trichomes (NGTs). GTs were further divided into seven subtypes including the capitate, subsessile capitate, sessile capitate, sunken, barrel, peltate, and clavate. Similarly, NGTs were also divided into simple unicellular and multicellular including conical, falcate, cylindrical, dendrite, papillose, and short hook shape. Quantitative measurement includes the length and width of the trichomes, stomatal complex, epidermal cells, stomata, and trichomes index. Based on the foliar micromorphological characters, a taxonomic key was developed to delimit and correctly identify studied taxa. Further molecular, other anatomical and phylogenetic studies are recommended to strengthen the systematics of Lamiaceae. 相似文献
80.
Nawazish A. Khan Rehana Begum Mazhar Mehmood 《Journal of Superconductivity and Novel Magnetism》2010,23(3):351-359
A reproducible synthesis and characterization of Zn-doped Cu0.5Tl0.5Ba2Ca2Cu3−y
Zn
y
O12−δ
(y=0, 0.5, 1.0, 1.5) superconductors at a relatively lower synthesis temperature of 840°C are studied by using X-ray diffraction,
resistivity, ac-susceptibility and FTIR absorption measurements. The X-ray diffraction (XRD) studies of these samples have
shown a tetragonal structure in which the c-axis length has been found to decrease with increased Zn doping. The critical temperature and magnitude of diamagnetism have
not been significantly affected with the doping of Zn at this synthesis temperature. The magnitude of diamagnetism in the
as-prepared undoped samples is decreased, whereas it remains stable (unchanged) in oxygen post-annealed samples. The apical
oxygen phonon’s modes of type Tl–OA–M(2) and Cu(1)–OA–M(2) {where M=Cu/Zn} and the planar oxygen phonon modes of type M(2)–OP–M(2) are also softened with the increase of Zn doping. We interpreted the softening of these oxygen related phonon modes
linked with the decreased c-axis length, reduced John–Teller distortions and increased mass of Zn (65.38 amu) as compared to that of Cu (63.54 amu) (Kaplan
et al., Phys. Rev. B 65, 214509, 2002). 相似文献