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91.
Ashkan Farazin Saeid Sahmani Maryam Soleimani Amin Kolooshani Saeed Saber-Samandari Amirsalar Khandan 《Ceramics International》2021,47(13):18339-18350
Porous bony scaffolds are utilized to manage the growth and migration of cells from adjacent tissues to a defective position. In the current investigation, the effect of titanium oxide (TiO2) nanoparticles on mechanical and physical properties of porous bony implants made of polymeric polycaprolactone (PCL) is studied. The bio-nanocomposite scaffolds are prepared with composition of nanocrystalline hydroxyapatite (HA) and TiO2 powder using the freeze-drying technique for different weight fractions of TiO2 (0 wt%, 5 wt%, 10 wt%, and 15 wt%). In order to identify the microstructure and morphology of the fabricated porous bio-nanocomposites, the X-ray diffraction (XRD), atomic force microscope (AFM) and scanning electron microscopy (SEM) are employed. Also, the biocompatibility and biodegradability of the manufactured scaffolds are examined by placing them in a simulated body fluid (SBF) for 21 days, their weight and pH changes are measured. The rate of degradation of the PCL-HA scaffold can be controlled by varying the percentage of its constituent components. Due to an increasing growth and activity of bone cells and the apatite formation on the free surface of the fabricated bio-nanocomposite implants as well as their reasonable mechanical properties, they have the potential to be used as a bone substitute. Additionally, with the aid of the experimentally extracted mechanical properties of the scaffolds, the vibrational characteristics of a beam-type implant made of the proposed porous bio-nanocomposites are explored. The results obtained from SEM image indicate that the scaffolds produced by the employed method have high total porosity (70%–85%) and effective porosity. The pore size is obtained between 60 and 200 μm, which is desirable for the growth and propagation of bone cells. Also, it is revealed that the addition of TiO2 nanoparticles leads to reduce the rate of dissolution of the fabricated bio-nanocomposite scaffolds. 相似文献
92.
Shahla Imani Moghaddam Hoda Pasdar Reza Fazaeli Saeed Mortazavi Nik 《Ceramics International》2021,47(15):20917-20922
Ferrites are an important group of magnetic materials which are used as absorbers. The incorporation of ferrite and conducting polymer achieves great enhancement in microwave absorption properties. The nanocomposites of hexagonal ferrites embedded by conducting polymers such as polypyrrole, polyaniline and polythiophene (PTH) have been paid much attention. In the present study, strontium hexagonal ferrite doped by Zr and Zn with the final formula of SrFe12-x(ZrZn)0.5xO19 considering x = 0.9 and embedded by PTH was produced to achieve a nanocomposite with the highest microwave absorbing ability. In this study, after synthesis of SrFe12O19(ZrZn)0.5xO19 and PTH, the nanocomposite was prepared by in situ polymerization. Wrapping the ferrite particles and PTH chains could form nanocomposite properly, and therefore acceptable interactions were observable between SrFe12-x(ZrZn)0.5xO19ferrite particles and PTH polymer chains in the composites. Assessing the X-ray diffraction (XRD) patterns of SrFe12-x(ZrZn)0.5xO19, PTH, and PTH/SrFe12-x(ZrZn)0.5xO19 nanocomposite indicated that the PTH characteristic peak shifts slightly and its peak intensity reduces, which may be attribute to the coating of PTH polymer chains onto SrFe12-x(ZrZn)0.5xO19 particles. We revealed also lower magnetic properties in the obtained nanocomposite. The morphological assessment also suggested that PTH could effectively coat the SrFe12-x(ZrZn)0.5xO19 particles. The synergistic effect of SrFe12-x(ZrZn)0.5xO19 particle plus PTH leads to microwave absorption percentage higher than 95% by PTH/SrFe12-x(ZrZn)0.5xO19 nanocomposite. Overall, nanocomposite creating by coupling interaction between SrFe12-x(ZrZn)0.5xO19 particles (x = 0.9) and PTH can effectively lead to achieve the highest rate of absorption of electromagnetic waves. 相似文献
93.
Zhale Gholampour Shamami Mir Saeed Seyed Dorraji Seyyedeh Fatemeh Hosseini Mohammad Hossein Rasoulifard Ismael Hajimiri Alireza Amani-Ghadim 《Ceramics International》2021,47(15):21334-21342
The current paper focuses on synthesizing a high-efficiency microwave absorber via incorporating the nanofillers of graphene oxide-polyaniline (GO-PANI), barium-strontium titanate (BST), and soft-hard ferrite within the polyester matrix. The nanocomposite magnets of (Ba0.5Sr0.5Fe12O19)1-x hard/(CoFe2O4)x soft (x = 0.2, 0.5, and 0.8) were prepared using sol-gel auto-combustion method. The GO-PANI and BST were successfully synthesized by in situ polymerization and improved polymerization, respectively. The phase structure, chemical structure, morphology, and microwave absorption properties of the synthesized nanocomposites were characterized by X-ray diffractometer (XRD), Fourier-transform infrared spectroscopy (FT-IR), and scanning electron microscope (SEM), vector network analyzer (VNA) techniques, respectively. The results showed that the synergistic effects of the combination of dielectric (BST), conductive (GO-PANI), and magnetic materials (hard-soft ferrites) provided the reflection loss values of less than ?20 dB (>99% absorption) in the X-band region. The minimum reflection loss of ?35 dB (>99.99% absorption) was obtained by the optimal formulation including (Ba0.5Sr0.5Fe12O19)0.2 (CoFe2O4)0.8, and the weight ratio of 1: 2 for both BST/soft-hard ferrite and hard-soft ferrite + BST/GO-PANI with the thickness of 1 mm. According to the results, the thickness factor plays a key role in improving the impedance matching. Consequently, the proposed nanocomposite can be employed as a novel kind of microwave absorbers with good impendence matching and high absorption. 相似文献
94.
Farida khan Naeem A Israf Ud Din T. Saeed Mshari A. Alotaibi Abdulrahman I. Alharthi Asad Habib Tabassum Malik 《Ceramics International》2021,47(4):4749-4757
In the present study, hexagonal boron nitride (h-BN) was synthesized from boric acid and melamine by thermal annealing method in a nitrogen atmosphere. The pure h-BN was used as an efficient sorbent for the uptake of Cd2+ ions from the solution phase. The kinetics and sorption studies of metal ions onto the h-BN were carried out in batch adsorption experiments at different temperature, time, pH, sorbent dosage, and concentration of metal ions. The optimum pH for the removal of the Cd2+ ions was found to be pH 7. The effect of temperature showed that the process of Cd2+ sorption remained endothermic in the range of 298 K–328 K. The Lagergren's first and Ho's second kinetic models were tested to interpret the adsorption kinetic data, however the present data was explained well by Ho's model for kinetics. The thermodynamic perameters ΔG, ΔS and ΔH were determined using the available adsorption data at different temperatures. The physicochemical properties of the synthesized product were also characterized before and after adsorption by different analytical techniques like FT-IR, TGA, XRD and Point of Zero Charge (PZC). The morphology of the surface was analyzed with the help of Scanning Electron Microscopy. The h-BN proved to be an efficient adsorbent for the uptake of the Cd2+ ions from aqueous media. 相似文献
95.
Stability of fortified whole wheat flour (WWF) was evaluated using NaFeEDTA, elemental iron, ZnSO4 and ZnO as fortificants. Fortified WWF was stored in tin boxes and polypropylene bags for 60 days under ambient storage condition (ASC) and controlled storage condition (CSC). Fortification significantly (p ? 0.05) decreased moisture and protein content and increased ash content to 5.44%, 6% and 23%, as compared to control. Fortified WWF, assayed periodically for mould contamination manifested a significant inhibition (∼1 log reduction) in flours containing elemental iron. Low storage temperature and relative humidity (RH) indicated lower level of mould count during extended storage time. Tin boxes, as storage material, exhibited a better protection against mould attack, acting as an effective barrier for moisture. Fortificants exerted a slight deteriorative effect on texture characteristics of the chapattis made of these flours but chapattis were still accepted by the judges. Zinc fortificants seemed like having little or no effect on the quality of the flours and chapattis, made of such flours. Shelf life of fortified flour may be extended by using elemental iron as fortificant and storing the product in tin boxes under relatively low temperature and RH. 相似文献
96.
Nikghalb Saeed Shokoohi Alireza Singh Vijay P. Yu Ruihong 《Water Resources Management》2016,30(13):4969-4984
Water Resources Management - Maintaining Environmental Flow (EF) plays a critical role in protecting rivers and their ecosystems. Because of shortage of data and limited financial resources in... 相似文献
97.
Javad Sayyad Amin Meysam Bahadori Moonyong Lee Tomoaki Kashiwao Saeed Rafiee 《Petroleum Science and Technology》2016,34(8):703-711
In this study, two mathematical models for hydrate formation process to separate carbon dioxide by a combination of two different kinds of organic and surfactant promoters are presented. Promoters such as sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, and dodecyl trimethyl ammonium chloride as surfactant promoters; also, tetrahydrofuran, cyclopentane, 1,3-dioxolane, and 2-methyl tetrahydrofuran as organic promoters have been used in recent years. The results showed that a combination of 3000 ppm of surfactant promoters and 4 wt% organic promoters had the highest separation rate of carbon dioxide and; consequently, the investigated models were based on this optimum condition. As a matter of fact, by using these simulations the hydrate formation behavior was predicted with high accuracy; moreover, conducting consuming experiments is not essential anymore. To sum up, in the present research both Vandermonde matrix model and Levenberg-Marquardt algorithm were applied to predict the hydrate formation behavior; in addition, their results were precisely considered and validated with experimental data. 相似文献
98.
Hamideh Hosseini Safa Saeed Morid Mahnoush Moghaddasi 《Water Resources Management》2012,26(8):2267-2281
Optimizing water allocations for the agricultural sector, the main water consumer, at the beginning of a period of drought is essential. However, long-term inflow forecasting, with its high uncertainty, is a necessary component of the allocation process. This paper presents a methodology that combines this uncertainty with economic factors to determine water allocation. The following models were developed and linked: optimization of agricultural water allocation under water scarcity, long-term flow forecast and quantification of forecast uncertainties. The approach coordinates economic values of water with system operational requirements. The Zayandeh Rud dam and irrigation system was selected to explore the methodology of this research. 相似文献
99.
The objective of this work is to implement a
pseudo-forward equation which is called PFE to transform
data (similarity attribute) to model parameters (porosity) in
a gas reservoir in the F3 block of North Sea. This equation
which is an experimental model has unknown constants in
its structure; hence, a least square solution is applied to find
the best constants. The results derived from solved equations
show that the errors on measured data are mapped
into the errors of estimated constants; hence, Tikhonov
regularization is used to improve the estimated parameters.
The results are compared with a conventional method such
as cross plotting between acoustic impedance and porosity
values to validate the PFE model. When the testing dataset
in sand units was used, the correlation coefficient between
two variables (actual and predicted values) was obtained as
0.720 and 0.476 for PFE model and cross-plotting analysis,
respectively. Therefore, the testing dataset validates relatively
well the PFE optimized by Tikhonov regularization
in sand units of a gas reservoir. The obtained results indicate
that PFE could provide initial information about
sandstone reservoirs. It could estimate reservoir porosity
distribution approximately and it highlights bright spots
and fault structures such as gas chimneys and salt edges. 相似文献
100.
The purpose of this paper is the quantitative analysis of the change in quality perception of four new processed beef products from pre to post trial phases. Based on the Total Food Quality Model, differences in pre and post-trial phases were measured using repeated measures technique for cue evaluation, quality evaluation and purchase motive fulfillment. For two of the tested products, trial resulted in a decline of the evaluation of cues, quality and purchase motive fulfillment compared to pre-trial expectations. For these products, positive expectations were created by giving information about ingredients and ways of processing, which were not confirmed during trial. For the other two products, evaluations on key sensory dimensions based on trial exceeded expectations, whereas the other evaluations remained unchanged. Several demographic factors influenced the pattern of results, notably age and gender, which may be due to underlying differences in previous experience. The study gives useful insights for testing of new processed meat products before market introduction. 相似文献