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371.
Daw Mohammad Abdalhadi Zulkifly Abbas Ahmad Fahad Ahmad Khamirul Amin Matori Fahmiruddin Esa 《Fibers and Polymers》2018,19(7):1513-1521
Microwave-absorptive polymer composite materials provide protection against interference to communication systems caused by microwave-inducing devices. Microwave-absorptive polymer composites were prepared from polylactic acid (PLA) biocomposite blended with oil palm empty fruit bunch (OPEFB) fiber and commercial Iron oxide (Fe2O3) as filler using the melt-blending method. The composites characterization was carried out using the scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses. The coefficient of reflection S11 and coefficient of transmission S21 of the composites for various Fe2O3 filler percentages were determined using a rectangular waveguide in connection with microwave vector network analyser (HP/Agilent model PNA N5227). These coefficients were then used to calculate microwave-absorption properties (in decibels). XRD analysis showed that increasing amounts of reinforced material (Fe2O3) reduces the crystallinity of the composites. SEM data indicated that Fe2O3 filler ratio increased in the composites, and adhesion to the cellulose fiber grew gradually until the highest percentage of filler was added. The complex relative permittivity and relative permeability were obtained within the broad frequency range of 8–12 GHz at room temperature for various percentages of filler and were measured by the transmission/reflection method using a vector network analyser. Fe2O3 embedment in OPEFB/PLA was observed to have resulted in enhancing the dielectric and magnetic properties. The values of permittivity and permeability increased with increasing Fe2O3 filler content. Theoretical simulation studied the relation between ε′ and ε″ of the relative complex permittivity in terms of Cole-Cole dispersion law. The result indicated that the processes of Debye relaxation in Fe2O3/OPEFB/PLA, the unique dielectric characteristics of Fe2O3 cannot be accounted for by both the Debye dipolar relaxation and natural resonance. Results further showed that the material transmission, reflection, and absorption properties could be controlled by changing the percentage of Fe2O3 filler in the composites. 相似文献
372.
Mehdi Vafakhah Amin Fakher Nikche Seyed Hamidreza Sadeghi 《Paddy and Water Environment》2018,16(3):411-424
The present study aims to evaluate performance of different infiltration models, namely initial and constant rate, soil conservation service (SCS) curve number and Green–Ampt in simulation of flood hydrographs for the small-sized Amameh Watershed, Iran. To achieve the study purpose, the infiltration rates were measured using rainfall simulator in work units acquired through overlaying topography, land use, drainage network and soil hydrologic group maps. All parameters of the study infiltration models were determined with the help of the Infilt. software package. The performances of the models in simulation of the observed output hydrographs from the entire watershed were ultimately evaluated for 28 rainfall–runoff events in the HEC-HMS environment. The different components of the observed and estimated hydrographs including time to peak, runoff volume, peak discharge, discharge values and peak time deviation were compared using relative error (RE), coefficient of determination (R2), peak-weighted root mean square error (PWRMSE) and Nash–Sutcliffe (NS) criteria. The general performance of estimations was also qualitatively assessed using scatter plot and distribution of study variables around standard lines of 1:1 slope. The results revealed that the SCS infiltration model with PWRMSE = 0.61 m3 s?1 and NS = 0.53 performed better than initial and constant rate model with PWRMSE = 1.1 m3 s?1 and NS = 0.54, and Green Ampt model with PWRMSE = 1.35 m3 s?1 and NS = 0.29 in estimation of flood hydrograph for the Amameh Watershed. 相似文献
373.
Nigella sativa (black cumin seed) as a biological detoxifier in diet contaminated with aflatoxin B1
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A. A. Rasouli‐Hiq F. Bagherzadeh‐Kasmani M. Mehri M. A. Karimi‐Torshizi 《Journal of animal physiology and animal nutrition》2017,101(5):e77-e86
Aflatoxin B1 (AFB1) is a common feed contaminant that adversely affects bird performance and product quality. A total of 600 7‐day‐old quail chicks were randomly allotted to eight experimental groups in a completely randomized design with five replicate pens and 15 quails per pen. Experimental treatments including two levels of AFB1 (0 and 2.5 mg/kg) and 4 levels of Nigella sativa (NS) (0, 0.5, 1.0 and 1.5% of diet) were offered from 7 to 35 days of age to quail chicks. Although feeding of AFB1 impaired gain (G) and feed conversion ratio, dietary NS increased G (p < 0.05). Relative weight of bursa of Fabricius increased with incremental levels of NS (p < 0.05). AFB1 decreased the size of heart, but incremental levels of NS increased the relative weight of heart (p < 0.05). The liver hypertrophy was observed in birds receiving AFB1 (p < 0.05). The birds in AFB1 group had smaller testes than other groups (p < 0.05). Hematocrit value in birds fed AFB1 was lower than that in other groups (p < 0.05) and incremental levels of NS increased blood hematocrit (p < 0.05). Amount of malondialdehyde (MDA) in meat samples of the birds fed AFB1 was higher than those did not receive toxin but incremental levels of NS decreased the MDA concentration in affected birds (p < 0.05). AFB1 suppressed the humoral immunity of the birds while NS augmented the antibody titres against sheep red blood cell and Newcastle disease virus antigens (p < 0.05). AFB1 decreased lactic acid bacteria (LAB) and spore‐forming bacteria (SFB) but increased Escherichia coli (E. coli; p < 0.05). However, NS increased LAB and SFB but decreased the E. coli populations (p < 0.05). This study revealed that NS as a biological detoxifier could relatively attenuate the negative effects of AFB1 in quails. 相似文献
374.
Oguzhan Uzun Sema Kaplan Selen Deviren Saygın Feras Youssef Amin Nouri 《Arid Land Research and Management》2017,31(2):125-139
Wind erosion is a serious land degradation phenomenon in semi-arid parts of Turkey. It is even becoming more critical problem considering the current effects of global warming and climate change in the region. The objectives of this study are to model spatial variation of aeolian sediment transport and to map Sediment Transport Rate (STR) by geostatistics in a fallow plot in the Central Anatolia. STRs for four consecutive wind cases with different vegetation cover rates were determined using the cyclone BEST sediment traps. Plant cover ratio and height changed between 8 and 25% and 3–12?cm throughout the research period, respectively, and soil moistures ranged between 10.9 and 12.7%. The windstorms lasted for 400, 835, 1240, and 50 minutes with the mean wind velocities of 8.6, 7.7, 7.7, and 6.3?m?s?1, respectively, for cases 1, 2, 3, and 4. The calculated STRs varied between 0.0248?±?0.0170?kg?m?1?h?1 and 0.190?±?0.084?kg?m?1?h?1. Spatial analysis revealed that the spatial correlations were between 19 and 48?m and different spatial patterns occurred from one case to another. The study results indicated that the amount of transported sediment and its spatial variation were mostly related to velocity and duration of erosive wind in the fallow area of the arid region. 相似文献
375.
Stevia (Stevia rebaudiana Bertoni) is a perennial plant producing some natural sweeteners. Stevia is considered as a new crop in some countries. This study was conducted to find the stevia response to nitrogen fertilizer supply. Different levels of nitrogen (0, 30, 60, 90, 120, and 150 kg/ha from urea source) were used in a greenhouse condition and then the stevia growth and metabolites were assessed under different availability of nitrogen. Results showed that the optimum growth of stevia was obtained by 60 kg/ha nitrogen and more nitrogen supply did not enhance the stevia growth. It was observed that the total steviol glycosides (SVglys) content of Stevia was significantly increased by nitrogen fertilizer application just up to 30 kg/ha, while it decreased by more rates of nitrogen fertilizer. Our result clearly showed that SVglys yield reached to maximum value by application of 60 kg/ha of nitrogen fertilizer. Since the variation of SVglys content and shoot growth of the stevia were compromised by 60 kg/ha nitrogen, it can be concluded that 60 kg/ha of nitrogen fertilizer could be considered as an optimum rate of nitrogen for stevia and could also be recommended for greenhouse conditions. 相似文献
376.
Arshad Ali Khan Muhammad Sajid Abdur Rab Noor ul Amin Farooq Shah 《Communications in Soil Science and Plant Analysis》2017,48(12):1486-1493
Nitrogen has a role in plant mineral nutrition, and so a better way of supplying nitrogenous fertilizers is demanded to promote plant nutrition and clean environment. The present study was, therefore, designed to maintain plant mineral requirements and control environmental pollution. Tomato cultivars, that is, Falcon and Rio Grande, were supplied with a mixture of poultry manure (PM) and urea in various proportions in 2009 and 2010. All tested factors (N source, cultivar, and year) alone and in combination significantly (P ≤ 0.05) affected the mineral profile of tomato fruit. Treatment 75:25 resulted in highest uptake of calcium (Ca), iron (Fe), zinc (Zn), and copper (Cu) in cultivar Rio Grande during 2010. Similarly, highest concentration of boron (B) was recorded in Rio Grande fed with 50:50 of PM and urea, respectively. It was concluded that a combination of PM and urea in ratios of 75:25 and 50:50 performed well in achieving the optimal mineral contents in the tomato fruits. 相似文献