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991.
Mohadese Hossien-poor-Zaryabi Mahmoud Chamsaz Tahereh Heidari Mohammad Hossein Arbab Zavar Mohammad Behbahani Mani Salarian 《Food Analytical Methods》2014,7(2):352-359
In the present study, dispersive liquid–liquid micro-extraction has been applied for trace extraction and determination of mercury (Hg) ions in environmental samples. The mean centering of ratio spectra method was used to optimize the experimental parameters affecting the extraction of Hg. The factors influencing the extraction procedure such as type and volume of extracting and disperser solvent, concentration of chelating reagent, pH, salt effect, and centrifuge time were investigated and optimized. Under the optimized conditions, the limit of detection of the method was 0.15 μg l?1 and enrichment factor was 39. The calibration curve was linear in the range of 0.5–100 μg l?1 with a correlation of determination (R 2) of 0.998. The relative standard deviation for determination of 40 μg l?1 of Hg(II) was 2.6 % (n?=?5). The proposed method was applied for the determination of Hg in pine leaf, sea and river fish, sand, and water samples as indicators of environmental pollution and cigarette with satisfactory analytical results. In comparison with other methods, the proposed method is very simple, easy, rapid, and sensitive for determination of Hg at trace levels in complex matrices. 相似文献
992.
Rezvan Shaddel Abdolmajid Maskooki Mohammad Hossein Haddad-Khodaparast Sodeif Azadmard-Damirchi Morteza Mohamadi Bahram Fathi-Achachlouei 《Food science and biotechnology》2014,23(5):1459-1468
Bene hull contains antioxidant components. Optimum conditions for bioactive compound extraction processes from Bene hull using subcritical water with response surface methodology (RSM) were obtained. Temperature (110–200°C), processing time (30–60 min), and the water to Bene hull ratio (10:1–50:1) were the investigated factors. The optimal conditions for maximizing the antioxidant activity were 196.8°C for 52.6 min and a ratio of 43.6:1 for water to Bene hull. Under these conditions, the amount of polyphenolic compounds, the reduction power (RP) (EC50), and the DPPH free radical scavenging activity (RSA) (EC50) were predicted to be 2,284 mg of gallic acid/100 g of Bene hull, 0.2002 mg/mL, and 0.6284 mg/mL, respectively. HPLC analysis was used to identify the main phenolic compounds. The subcritical water extraction technique could be used as a beneficial method to obtain bioactive compounds from Bene hull. 相似文献
993.
Maryam Fallah Najafabadi Hossein Talebi Rostami Khashayar Hosseinzadeh Davood Domiri Ganji 《亚洲传热研究》2021,50(8):7553-7567
In this study, the heat transfer and temperature distribution in a moving fin have been analyzed. The fin velocity was considered constant, and the thermal conductivity coefficient was variable with temperature, and the fin was under the effect of convection, radiation, and conduction heat transfer. The main equation of the problem was solved by the radial basis function method and validated by the numerical 4th-order Runge–Kutta method. Several parameters such as thermal conductivity parameter from 0 to 1, sink temperature parameter from 0.2 to 0.8, and Nr, Nc, Pe number from 1 to 4, were examined. The outcomes illustrate that increasing the thermal conductivity by 51.5% raises the conduction heat transfers as well as the dimensionless temperature by 3.42%. Moreover, increasing the sink temperature leads to a slow rise in ambient temperature by 22.8% in the maximum state. By raising the Nc and Nr parameters, near 33.3%, the temperature distribution profile is declined by 4% and 10.5%, respectively. And increasing the Pe number by 100% results in a rise in the temperature distribution by about 7%. 相似文献
994.
Amir Hossein Saberi Lai Oi‐ Ming Mat Sahri Miskandar 《European Journal of Lipid Science and Technology》2011,113(5):627-636
Ternary mixtures containing palm olein (POL), palm kernel oil (PKO) and palm oil‐based diacylglycerol (PO‐DAG) were designed using mixture design. The corresponding physical properties such as solid fat content (SFC) as well as deviation from SFC (ΔSFC) using nuclear magnetic resonance (NMR) and melting and crystallization properties using differential scanning calorimetry (DSC) were studied. Ternary phase behaviour was analysed using isosolid diagrams. The most intensive eutectic interaction among the three binary blends studied was observed along the binary line of PKO/PO‐DAG followed by POL/PKO and POL/PO‐DAG. The higher ΔSFC did not always lead to the more intensive eutectic behaviour among the blends. Addition of pure POL, 33.33 and 66.66% POL, and no POL to 50/50 mixture of PKO/PO‐DAG decreased heat of crystallization (ΔHc) as well as crystallization onset (TO). However, as the same amounts of PO‐DAG and PKO were added to the 50/50 mixtures of POL/PKO and POL/PO‐DAG, respectively, blend containing the equi‐mixture of POL, PKO and PO‐DAG (33.33/33.33/33.33) was found to have the lowest ΔHc. This was also reflected in the corresponding eutectic effect observed at 20–25 and 5–10°C, respectively. Palm‐based DAG‐enriched shelf‐stable margarine consisting of POL/PKO/PO‐DAG (42.5/42.5/15 w/w) was optimally formulated through analysis of multiple isosolid diagrams and was found to have quite similar SFC profile with commercial shelf‐stable margarine. Practical applications: In this study, valuable information about complicated interactions among the palm oil‐based diacylglycerol (PO‐DAG) and palm‐based oils with different FA chain length was obtained in the ternary system. These informative data may be useful in future exploitation of solid fat‐based DAG in blend with natural fats for various DAG‐enriched plastic fat products. Furthermore, Design Expert software was found to be a valuable tool to optimize the new fat blend formulation using the minimum number of blend preparation. By using this tool, assessment of complicated behaviour among the blend components through construction of the corresponding phase diagrams which are critical for optimization purposes as well as fat product development, would also be possible. 相似文献
995.
Abdollah Arasteh Alireza Aliahmadi Hossein Mahmoodi Sefidkoohi Mohammad Mohammadpour Omran 《The International Journal of Advanced Manufacturing Technology》2011,56(1-4):261-272
Queuing networks present as beneficial models for a category of problems emerging in modern manufacturing systems. As the optimal control problem for queuing networks in familiar to be difficult, an important topic of research during the last two decades has been the growth of difficult estimations, and the use of these estimations to control optimal controls. Flexible moderations are an important class of such estimations that have received much consideration in recent years. The central objective of this paper is to determine the utilization of flexible moderations in solving a diversity of scheduling problems. In this paper, we investigate the role of flexible moderations in solving classic job shop problems. For the job shop problem with the objective of minimizing makespan, we build a schedule that is guaranteed to be within a consistent of the optimal. In other words, we examine the job shop scheduling problem with the aim of minimizing holding costs. Recent results show that for this objective, the job shop problem does not have a polynomial time estimation plan; consequently, in terms of approximability, this is a harder objective than the makespan. Our main result is an algorithm, based on regular relaxation that presents lateral optimal schedules. 相似文献
996.
Compressed sensing for real-time energy-efficient ECG compression on wireless body sensor nodes 总被引:3,自引:0,他引:3
Mamaghanian H Khaled N Atienza D Vandergheynst P 《IEEE transactions on bio-medical engineering》2011,58(9):2456-2466
Wireless body sensor networks (WBSN) hold the promise to be a key enabling information and communications technology for next-generation patient-centric telecardiology or mobile cardiology solutions. Through enabling continuous remote cardiac monitoring, they have the potential to achieve improved personalization and quality of care, increased ability of prevention and early diagnosis, and enhanced patient autonomy, mobility, and safety. However, state-of-the-art WBSN-enabled ECG monitors still fall short of the required functionality, miniaturization, and energy efficiency. Among others, energy efficiency can be improved through embedded ECG compression, in order to reduce airtime over energy-hungry wireless links. In this paper, we quantify the potential of the emerging compressed sensing (CS) signal acquisition/compression paradigm for low-complexity energy-efficient ECG compression on the state-of-the-art Shimmer WBSN mote. Interestingly, our results show that CS represents a competitive alternative to state-of-the-art digital wavelet transform (DWT)-based ECG compression solutions in the context of WBSN-based ECG monitoring systems. More specifically, while expectedly exhibiting inferior compression performance than its DWT-based counterpart for a given reconstructed signal quality, its substantially lower complexity and CPU execution time enables it to ultimately outperform DWT-based ECG compression in terms of overall energy efficiency. CS-based ECG compression is accordingly shown to achieve a 37.1% extension in node lifetime relative to its DWT-based counterpart for "good" reconstruction quality. 相似文献
997.
Off-axis electron holography has been extended to in situ observations in gas atmospheres. The Yttria-stabilized zirconia (YSZ)-Pt hetero-interface was characterized by electron holography at high temperature in a vacuum and in an oxygen atmosphere. Analysis of the phase shift profiles revealed high mobility of anions in the oxide in the vicinity of the interface in the oxygen atmosphere. This would compensate for any increase in the number of oxygen vacancies in YSZ through the metal interface. 相似文献
998.
Peiman Aliparast Ziaddin Daie Koozehkanani Abdolhamid Moallemi Khiavi Ghader Karimian Hossein Balazadeh Bahar 《Analog Integrated Circuits and Signal Processing》2011,66(2):235-243
This paper presents a new high-speed CMOS 4-2 compressor which is an essential part in fast digital arithmetic integrated
circuits. Current-mode techniques have been used to improve the overall performance of the compressor. New fully differential
proposed circuit improves speed up to 45% also reduces occupied area in comparison to other high-speed conventional compressor
circuits. To evaluate the performance of the proposed circuit, two other structures have been chosen and all of the circuits
have been simulated in 0.18 μm standard TSMC CMOS process with 1.8 V power supply voltage. 相似文献
999.
Mina Shahi Amir Houshang Mahmoudi Farhad Talebi 《International Communications in Heat and Mass Transfer》2011,38(4):533-542
Laminar conjugate heat transfer by natural convection and conduction in a vertical annulus formed between an inner heat generating solid circular cylinder and an outer isothermal cylindrical boundary has been studied by a numerical method. It is assumed that the two sealed ends of the tube to be adiabatic. Governing equations are derived based on the conceptual model in the cylindrical coordinate system. The governing equations have been solved using the finite volume approach, using SIMPLE algorithm on the collocated arrangement. Results are presented for the flow and temperature distributions and Nusselt numbers on different cross sectional planes and longitudinal sections for Rayleigh number ranging from 105 to 108, solid volume fraction of 0‹φ‹0.05 with copper-water nanofluid as the working medium. Considering that the driven flow in the annular tube is strongly influenced by orientation of tube, study has been carried out for different inclination angles. 相似文献
1000.
K. Ait-Hamouda N. Gabouze T. Hadjersi N. Benrekaa R. Outemzabet H. Cheraga K. Beldjilali Br. Mahmoudi 《Solar Energy Materials & Solar Cells》2003,76(4):287
An experimental study of the influence of solution resistivity and the effect of post-anodizing treatments of PS films on the electrical and optical properties of the metal/PS/Si photodiodes was performed. Porous silicon (PS) samples were made from p-Si in ethylene-glycol/HF or ethanol/HF solutions of different concentrations. The anodized sample was left in the dark for different times in the HF/base electrolyte in which the porous layer had been fabricated or in methanol. The results show a strong influence of the etching solution parameters and PS surface post-treatments on kinetic changes of the device's electrical properties. The mechanism of electrical conduction was interpreted in terms of charge carrier transport through shallow traps associated with the surface impurities. 相似文献