Sharif Digital Repository

This study explores the intricate interaction of thermal radiation, chemical reactions, Brownian motion, and thermophoresis on heat and mass transfer within a magnetic nanofluid, flowing over a porous stretching surface. Current models in the literature are limited in their ability to account for the complex dynamics governing this process, particularly with respect to nonlinear variations in fluid momentum, temperature, and mass diffusion. To overcome these limitations, we propose an enhanced approach utilizing the Darcy–Forchheimer fluidic model (DFM), which integrates these nonlinear effects and addresses both momentum and mass diffusion. Our model is distinct in its application of... 

Mixed matrix membranes (MMMs) with enhanced selectivity and permeability are investigated by incorporating deep eutectic solvents (DES) functionalized CeO2 as fillers. DES is well known owing to the intrinsic benefits of low cost, environmentally friendly, biodegradable, and CO2 philic nature. Characterization confirms the collaboration of polymer and functional CeO2 fillers. Experiments of gas separation show that the introduction of DES-modified CeO2 fillers (2%–15%) significantly improves CO2 penetrability from 27 to 48 Barrer. The ideal separation factor of CO2/CH4 and CO2/N2 also increases from 46 to 62 and 60 to 86, respectively, with increasing filler percentage. MMMs correspond to... 

Focusing on the Lower Bari Doab Canal (LBDC) command area, characterized by its heavy reliance on agriculture, this study addresses the critical issue of groundwater table fluctuations in response to diverse pumping scenarios. Herein, we comprehensively evaluated the dynamic interplay between crop water requirements and groundwater pumping within the expansive canvas of the LBDC, which is facing water shortages. Using the Penman–Monteith equation, we calculated annual average evapotranspiration for major crops—wheat, maize, cotton, rice, and sugarcane. Three-dimensional MODFLOW-based numerical modeling was used to analyze the dynamics of groundwater regimes. MODFLOW was calibrated from 2010... 

Volatile organic compounds (VOCs) are a major class of pollutants that are hazardous to human health and environment. An emerging and successful technology for the treatment of VOC, even at low concentrations is nonthermal plasma (NTP). However, it has the disadvantages of generating undesired by-products and is less energy efficient. In this work, the NTP is combined with ferrite-based catalysts Co–Zn–Fe2O4, Co–Fe2O4, and Zn–Fe2O4 are prepared by the coprecipitation method to study the impact of input power (11–44 W), CO2 selectivity, NOx, O3, and undesired by-product generation for the degradation of toluene as representing VOC. The NTP with catalysts significantly improves the removal... 

The current study was conducted at Ali-Ul-Murtaza Department of Rehabilitation Sciences, Muhammad Institute of Medical and Allied Sciences, Multan, Pakistan, from October to December 2022 to explore the correlation of body mass index with cardiometabolic and cardiorespiratory parameters in 393 male and female healthcare professionals, including physiotherapists, pharmacists and medical laboratory technicians, aged 22-40 years. The evaluation was on the basis of the Physical Activity Readiness Questionnaire, body mass index, lipid profile, body fat and correlation of blood pressure, temperature, oxygen saturation, respiration rate and heart rate with cardiorespiratory fitness assessed through... 

The increase of pesticide residues in food is extremely dangerous for humans. This research aimed to determine the concentrations of left-over pesticides residues on mangoes after they were exposed to pesticide residue mitigation modules (PRMM). Among these, four modules were used as candidate for integrated pest management approaches, while the fifth was traditional and served as a control. Residues of the lambda-cyhalothrin, cypermethrin, indoxacarb, imidacloprid, pyriproxyfen, acetamiprid, buprofezin and chlorpyrifos pesticides were assessed from mangoes taken from orchards. The QuEChERS technique was used to extract the residue samples and the GC-MS for their quantification. A... 

According to Arthur (2006, p. 200), “Through the use of literature, a language learning experience might become at the same time a source of immediate pleasure and satisfaction for the student. This possibility makes literature an appealing teaching device for ESL teachers”. However, numerous factors may contribute to the teachers’ lack of interest in using literary texts as a teaching tool. This study was an attempt to investigate Iranian EFL teachers’ attitude toward using literature in language classes and their perception toward the probable reasons of some teachers’ lack of interest in doing so. Altogether forty-four language teachers (19 females and 25 males, with a mean age of 26)... 

In this study, the inclusion of multi-walled carbon nanotubes as the second phase in the hydroxyapatite matrix, in order to improve the mechanical strength, has been performed via the sol-gel process. The stability of carbon nanotube sol with the changes of pH and dispersant values (sodium dodecyl sulfate) was evaluated by zeta potential analysis. The results indicated that synthesis of hydroxyapatite particles in the presence of the carbon nanotubes had the best result in homogenization of the carbon nanotube dispersion and faster crystallization of hydroxyapatite. The crystallization of hydroxyapatite phase was investigated with differential scanning calorimetry (DSC) and X-ray diffraction... 

The unwanted effects of diffraction and defocus aberration in three-dimensional integral imaging are taken into account by using the Fourier optics approach. The concepts of point spread function and optical transfer function widely in use for conventional two-dimensional imaging are generalized and applied to three-dimensional integral imaging systems. The effects of diffraction and defocus aberration are then studied and the performance of the conventional single lens imaging system is compared against that of the integral imaging  

High temperature shape memory NiTiHf thin films with varying hafnium contents up to 28.7 at.% were fabricated by DC magnetron sputtering using simultaneous sputter deposition from separate elemental targets. The required film composition was achieved by adjusting the power ratio to the targets. The as-deposited films were amorphous; a post deposition annealing was performed at 550 °C to crystallize the films. Two-micron thick films were characterized by energy dispersive spectroscopy in a scanning electron microscope, temperature controlled X-ray diffraction, differential scanning calorimetry, and atomic force microscopy. The results showed that above 10 at.% Hf additions the transformation... 

Consider Myerson's optimal auction with respect to an inaccurate prior, e.g., estimated from data, which is an underestimation of the true value distribution. Can the auctioneer expect getting at least the optimal revenue w.r.t. the inaccurate prior since the true value distribution is larger? This so-called strong revenue monotonicity is known to be true for single-parameter auctions when the feasible allocations form a matroid. We find that strong revenue monotonicity fails to generalize beyond the matroid setting, and further show that auctions in the matroid setting are the only downward-closed auctions that satisfy strong revenue monotonicity. On the flip side, we recover an approximate... 

In this study, an attempt has been made using different concentrations of rare-earth (RE) elements Yb, Gd in Ni–Zn spinel ferrite to examine the magneto-optical and electrical conductivity analysis of the prepared samples. RE doped Ni–Zn ferrite with composition Ni0.5Zn0.5YbxGdxFe2-xO4 (where, x = 0.00, 0.20, 0.40, 0. 60, 0.80 and 1.00) were prepared by one step sol-gel self-ignition approach. XRD and FESEM were used to examine the formation of a single-phase and variations in the grain size with the increasing contents of RE elements in Ni–Zn ferrite NPs. FTIR confirmed the vibrational studies of the RE doped spinel ferrite. The saturation magnetization, remanence, and coercivity elucidated... 

In recent years, subsidy payment has been made a main challenge for governments due to growth of population and energy price in global markets. Targeted subsidy plan has been implemented in Iran since last year, and this article discusses its effects on costs and revenues of Tehran Electricity Company as one of the major subdivisions of Iran's electricity industry. In the new system, structural changes have been made in electricity tariffs, so it is not possible to predict the future trends in electricity consumption only based on the past consumptions. In order to model the decision making structure in the recent conditions, a system dynamics method is applied. In addition to modeling the... 

In this study, an attempt has been made using different concentrations of rare-earth (RE) elements Yb, Gd in Ni–Zn spinel ferrite to examine the magneto-optical and electrical conductivity analysis of the prepared samples. RE doped Ni–Zn ferrite with composition Ni0.5Zn0.5YbxGdxFe2-xO4 (where, x = 0.00, 0.20, 0.40, 0. 60, 0.80 and 1.00) were prepared by one step sol-gel self-ignition approach. XRD and FESEM were used to examine the formation of a single-phase and variations in the grain size with the increasing contents of RE elements in Ni–Zn ferrite NPs. FTIR confirmed the vibrational studies of the RE doped spinel ferrite. The saturation magnetization, remanence, and coercivity elucidated... 

Understanding the nature of interaction between metal nanoparticles and biomolecules such as amino acids is important in the development and design of biosensors. In this paper, binding of M3 clusters (M = Au, Ag and Cu) with neutral and anionic forms of histidine amino acid was studied using density functional theory (DFT-B3LYP). It was found that the interaction of histidine with M3 clusters is governed by two major bonding factors: (a) the anchoring N-M and O-M bonds and (b) the nonconventional N-H⋯M and O-H⋯M hydrogen bonds. The nature of these chemical bonds has been investigated based on quantum theory of atoms in molecules (QTAIM) and natural bond orbital (NBO) analyses. In the next... 

The relative stabilities and noncovalent interactions of the six low-lying energy tautomers of cytosine nucleobase with some biological anions (such as F-, Cl-, and CN-) have been investigated in gas phase by density functional theory (DFT) method in conjunction with 6-311++G (d,p) atomic basis set. Furthermore, to systematically investigate all possible tautomerisms from cytosine induced by proton transfer, we describe a study of structural tautomer interconversion in the gas phase and in a continuum solvent using DFT calculation. We carried out geometrical optimizations with the integral equation formalism of polarizable continuum (IEF-PCM) model to account for the solvent effect, and the... 

Understanding the nature of the interaction between metal nanoparticles and biomolecules has been important in the development and design of sensors. In this paper, structural, electronic, and bonding properties of the neutral and anionic forms of glutathione tripeptide (GSH) complexes with a Au 3 cluster were studied using the DFT-B3LYP with 6-31+G**-LANL2DZ mixed basis set. Binding of glutathione with the gold cluster is governed by two different kinds of interactions: Auâ€"X (X = N, O, and S) anchoring bond and Au··•·•H-X nonconventional hydrogen bonding. The influence of the intramolecular hydrogen bonding of glutathione on the interaction of this peptide with the gold cluster has been... 

As digital technology has developed, relays have evolved from simple electro-mechanical devices into robust microprocessor-embedded intelligent electronic devices (IEDs). Distance protection, one of the most important and sophisticated forms of substation protection, quickly and selectively detects and clears phase faults in sub-transmission and transmission lines. The installation of a substation automation system (SAS) involves implementing control, monitoring, and protection logic by programming the IEDs and providing an appropriate communication network. IEC61850 has gradually satisfied the need for a standard communication protocol so that IEDs from different manufacturers can... 

The first asymmetric synthesis of α,β-disubstituted γ-phosphono sulfonates is reported. The key step is the Michael addition of a lithiated enantiopure sulfonate bearing an inexpensive chiral sugar auxiliary to α,β-unsaturated phosphonates in good diastereoselectivities. After chromatographic purification, the cleavage of the chiral sugar auxiliary proceeds without any epimerization or racemization to form the corresponding isopropyl sulfonate in very good overall yield (75%) and excellent diastereomeric and enantiomeric excess (de, ee ≥ 95%). © 2009 Elsevier Ltd. All rights reserved