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11.
Maissa Farhat Oscar Barambones Lassâad Sbita 《International Journal of Adaptive Control and Signal Processing》2017,31(11):1655-1665
In this paper, a photovoltaic system topology incorporating a new maximum power point tracking (MPPT) controller method is presented. This method uses an autotuning estimator and a PI controller to make the system work in the maximum power point. The controller is formulated based on the bijectivity in the photovoltaic generator characteristic; therefore, if the optimal voltage is reached, this means that the maximum of power is obtained. The proposed MPPT algorithm is implemented on a dSpace DS1104 controller board. In order to demonstrate the efficiency of the proposed algorithm in real time, an experimental setup using a boost converter connected to a resistive load is successfully implemented and studied. The obtained experimental results prove the validity of the proposed MPPT algorithm. 相似文献
12.
Hasnia Benmoussa Asma Farhat Rafik Bachoual Zina Nasfi Mehrez Romdhane 《分离科学与技术》2016,51(13):2145-2152
The present study aims to compare two innovative extraction techniques: microwave-assisted hydrodistillation (MAHD) and solvent-free microwave extraction (SFME) through traditional extraction techniques: hydrodistillation (HD) and steam distillation (SD) for their efficiency in the extraction of the volatile compounds from Tunisian Thymus vulgaris leaves; the kinetic, yield, composition and antibacterial activities of the essential oil were assessed in vitro. Results show that the essential oils extracted by microwaves were quantitatively (yield) similar to those obtained through the conventional methods, but qualitatively, essential oils analysed by gas chromatography–mass spectrometry (GC–MS) presented 17, 11, 11 and 8 compounds obtained through SFME, MAHD, SD and HD, respectively, mostly consisting of carvacrol (89.24–41.17%), followed by γ-terpinene (11.37–1.37%) and para-cymene (27.95–2.05%). The essential oils were screened for antibacterial activity against 5 microorganisms. All essential oils obtained by studied extraction methods showed the same resistance against Gram (?) and Gram (+) bacteria. The SFME method gave the best results: rapid kinetic of extraction (30 min vs. 35 min for MAHD, 120 min for SD, and 180 min for HD), less energy saving and cleanest process. 相似文献
13.
Adil Farooq Arfa Iqbal Nosheen Fatima Rana Misha Fatima Tuba Maryam Farhat Batool Zahra Rehman Farid Menaa Shabia Azhar Afrah Nawaz Faheem Amin Zuhair M. Mohammedsaleh Salma Saleh Alrdahe 《International journal of molecular sciences》2022,23(6)
Chronic liver disease (CLD) is a global threat to the human population, with manifestations resulting from alcohol-related liver disease (ALD) and non-alcohol fatty liver disease (NAFLD). NAFLD, if not treated, may progress to non-alcoholic steatohepatitis (NASH). Furthermore, inflammation leads to liver fibrosis, cirrhosis, and hepatocellular carcinoma. Vitexin, a natural flavonoid, has been recently reported for inhibiting NAFLD. It is a lipogenesis inhibitor and activates lipolysis and fatty acid oxidation. In addition, owing to its antioxidant properties, it appeared as a hepatoprotective candidate. However, it exhibits low bioavailability and low efficacy due to its hydrophobic nature. A novel rat model for liver cirrhosis was developed by CCL4/Urethane co-administration. Vitexin encapsulated liposomes were synthesized by the ‘thin-film hydration’ method. Polyethylene glycol (PEG) was coated on liposomes to enhance stability and stealth effect. The diseased rats were then treated with vitexin and PEGylated vitexin liposomes, administered intravenously and orally. Results ascertained the liposomal encapsulation of vitexin and subsequent PEG coating to be a substantial strategy for treating liver cirrhosis through oral drug delivery. 相似文献
14.
DRYING KINETICS AND CHARACTERISTIC DRYING CURVE OF LIGHTLY SALTED SARDINE (SARDINELLA AURITA) 总被引:5,自引:0,他引:5
Drying of lightly salted sardine (Sardinella aurita) was accomplished using three air temperatures (35°C, 40°C, 50°C) and three air velocities (0.5 m/s, 1.5 m/s, 2 m/s); the effects of drying conditions on drying kinetics were studied. As for all biological products, air temperature is the main factor influencing the drying kinetics. However, over a given temperature which seems to correspond to protein modification (50°C), and at a high air flow rate (2 m/s and 2.5 m/s) a crust formation on the surface of the fish, due to the combined effect of heat and salt was observed. This phenomenon inhibited the drying rate. From the drying curves, two falling rate periods were observed. The dimensionless drying rate versus a dimensionless moisture content data were regressed by the Marquardt Levenberg non-linear optimization method to obtain an empirical equation describing the salted sardine characteristic drying curve. 相似文献
15.
Adsorption of nitrate and monovalent phosphate anions from aqueous solutions on mono, di‐ and tri‐ammonium‐functionalised mesoporous SBA‐15 silica was investigated. The adsorbents were prepared via a post‐synthesis grafting method, using either 3‐aminopropyltrimethoxysilane (N‐silane) or [1‐(2‐aminoethyl)‐3‐aminopropyl]trimethoxysilane (NN‐silane) or 1‐[3‐(trimethoxysilyl)‐propyl]‐diethylenetriamine (NNN‐silane), followed by acidification in HCl solution to convert the attached surface amino groups to positively charged ammonium moieties. The nominal loading of amino moieties on the SBA‐15 surface was varied from 5% to 20% as organoalkoxysilane/silica molar ratio. The adsorption experiments were conducted batchwise at room temperature. Results showed that adsorption capacity increased with increasing the concentration of monoammonium groups on the SBA‐15 adsorbent. Nitrate adsorption capacity increased from 0.34 to 0.66 mmol ${\rm NO}_{3}^{{-} } /{\rm g}$ adsorbent while phosphate adsorption capacity increased from 0.34 to 0.63 mmol ${\rm H}_{2} {\rm PO}_{4}^{{-} } /{\rm g}$ adsorbent when the molar ratio organoalkoxysilane/silica was varied from 5% to 20%, respectively. Also, for the same organoalkoxysilane/silica molar ratio of 10%, the adsorption capacity increased with the increase of the number of protonated amines in the functional groups. Therefore, maximum adsorption capacities of 0.80, 1.16 and 1.38 mmol ${\rm NO}_{3}^{{-} } /{\rm g}$ adsorbent and 0.72, 0.82 and 1.17 mmol ${\rm H}_{2} {\rm PO}_{4}^{{-} } /{\rm g}$ adsorbent were obtained using mono‐, di‐ and triammonium functionalised SBA‐15 adsorbents, respectively. © 2011 Canadian Society for Chemical Engineering 相似文献
16.
Jie Yuan Ning Song Nabil Farhat Jan Van der Spiegel 《Analog Integrated Circuits and Signal Processing》2009,59(3):287-300
The clustering of spatio-temporal patterns are essential for many applications. Established from the biological analogy of
the cortex, the parametrically coupled logistic map network (PCLMN) provides a viable solution to the clustering problem.
To engineer for a single-chip spatio-temporal pattern clustering system, the highly modular PCLMN is designed in analog circuit.
In this paper, the 0.6 μm 5 V CMOS design of the processing element is presented. The analog design employs self-calibration
techniques to improve the accuracy and robustness of the nonlinear circuits. A fabricated element covers a die area of 0.55
mm2, and consumes 240 mW power at 5 V supply. After calibration, simulation and testing results show that the element fulfills
the system-level requirement of the Cort-X model for driving signals up to 1 MHz. 相似文献
17.
H. Bavestrello P. Avery C. Farhat 《Computer Methods in Applied Mechanics and Engineering》2007,196(8):1347-1368
Two approaches are presented for extending the FETI-DP domain-decomposition-based iterative method to the solution of problems with Linear Multipoint Constraints (LMPCs). Both cases of arbitrary LMPCs and LMPCs generated by the mortar method for enforcing a weak continuity of the solution across non-matching finite element interfaces are considered. In the first approach, the LMPCs are addressed during the preconditioning step but enforced only at convergence. In the second approach, the LMPCs are enforced at each iteration through the solution of an auxiliary coarse problem. Both extended FETI-DP solvers are benchmarked on a parallel processor for a wide range of constrained structural mechanics problems. The obtained results reveal that both solvers are numerically scalable and complement each other from the memory and CPU performance viewpoints. 相似文献
18.
19.
The range profiles and images of a straight wire without and with lumped impedance loading are discussed and demonstrated. The scattering mechanisms of a straight wire are qualitatively analyzed using the method of moments. Plots of range profiles at different aspect angles show that surface traveling waves are important scattering mechanisms of a straight wire. The presence of traveling wave makes ringlike artifacts appear in the reconstructed images. It was found that lumped impedance loading can effectively distort the range profiles and microwave images of a wire scatterer. In addition, randomly varied reactive loading can generate random peaks in the range profiles 相似文献
20.
An improved desulfurization process for removing sulfur from hydro treated diesel oil based on the oxidation of thiophenic type sulfur-containing compounds with H2O2 and acetic acid (AcOH) using H2SO4 as catalyst has been studied. The experimental results show that the sulfone content in the oxidation product increased rapidly with an increase in acetic acid and sulfuric acid ratios from 1:0 to 2:1 mole ratios. The maximum DBT conversion (wt.%) was at 2:1 mole ratio of acetic acid/sulfuric acid. This oxidation process is found to be capable of removing up to 90% of the sulfur compounds in hydro treated real fuels and can provide an alternative way to meet the future sulfur environmental requirements. 相似文献