Showing papers by "Islamic Azad University published in 2016"

Multi-Verse Optimizer: a nature-inspired algorithm for global optimization

Abstract: This paper proposes a novel nature-inspired algorithm called Multi-Verse Optimizer (MVO). The main inspirations of this algorithm are based on three concepts in cosmology: white hole, black hole, and wormhole. The mathematical models of these three concepts are developed to perform exploration, exploitation, and local search, respectively. The MVO algorithm is first benchmarked on 19 challenging test problems. It is then applied to five real engineering problems to further confirm its performance. To validate the results, MVO is compared with four well-known algorithms: Grey Wolf Optimizer, Particle Swarm Optimization, Genetic Algorithm, and Gravitational Search Algorithm. The results prove that the proposed algorithm is able to provide very competitive results and outperforms the best algorithms in the literature on the majority of the test beds. The results of the real case studies also demonstrate the potential of MVO in solving real problems with unknown search spaces. Note that the source codes of the proposed MVO algorithm are publicly available at http://www.alimirjalili.com/MVO.html.

Smart micro/nanoparticles in stimulus-responsive drug/gene delivery systems

Abstract: New achievements in the realm of nanoscience and innovative techniques of nanomedicine have moved micro/nanoparticles (MNPs) to the point of becoming actually useful for practical applications in the near future. Various differences between the extracellular and intracellular environments of cancerous and normal cells and the particular characteristics of tumors such as physicochemical properties, neovasculature, elasticity, surface electrical charge, and pH have motivated the design and fabrication of inventive “smart” MNPs for stimulus-responsive controlled drug release. These novel MNPs can be tailored to be responsive to pH variations, redox potential, enzymatic activation, thermal gradients, magnetic fields, light, and ultrasound (US), or can even be responsive to dual or multi-combinations of different stimuli. This unparalleled capability has increased their importance as site-specific controlled drug delivery systems (DDSs) and has encouraged their rapid development in recent years. An in-depth understanding of the underlying mechanisms of these DDS approaches is expected to further contribute to this groundbreaking field of nanomedicine. Smart nanocarriers in the form of MNPs that can be triggered by internal or external stimulus are summarized and discussed in the present review, including pH-sensitive peptides and polymers, redox-responsive micelles and nanogels, thermo- or magnetic-responsive nanoparticles (NPs), mechanical- or electrical-responsive MNPs, light or ultrasound-sensitive particles, and multi-responsive MNPs including dual stimuli-sensitive nanosheets of graphene. This review highlights the recent advances of smart MNPs categorized according to their activation stimulus (physical, chemical, or biological) and looks forward to future pharmaceutical applications.

Application of liposomes in medicine and drug delivery.

Abstract: Liposomes provide an established basis for the sustainable development of different commercial products for treatment of medical diseases by the smart delivery of drugs. The industrial applications include the use of liposomes as drug delivery vehicles in medicine, adjuvants in vaccination, signal enhancers/carriers in medical diagnostics and analytical biochemistry, solubilizers for various ingredients as well as support matrices for various ingredients and penetration enhancers in cosmetics.In this review, we summarize the main applications and liposome-based commercial products that are currently used in the medical field.

Parameter estimation of solar photovoltaic (PV) cells: A review

Abstract: The contribution of solar photovoltaics (PV׳s) in generation of electric power is continually increasing. PV cells are commonly modelled as circuits. Finding appropriate circuit model parameters of PV cells is crucial for performance evaluation, control, efficiency computations and maximum power point tracking of solar PV systems. The problem of finding circuit model parameters of solar PV cells is referred to as “PV cell model parameter estimation problem,” and is highly attracted by researchers. In this paper, the existing research works on PV cell model parameter estimation problem are classified into three categories and the research works of those categories are reviewed. Based on the conducted review, some recommendations for future research are provided.

Application of gold nanoparticles in biomedical and drug delivery

Abstract: Nanoparticles are the simplest form of structures with sizes in the nanometer (nm) range. In principle any collection of atoms bonded together with a structural radius of 100 nm can be considered nano particles. Nanotechnology off ers unique approaches to probe and control a variety of biological and medical processes that occur at nanometer scales, and is expected to have a revolutionary impact on biology and medicine. Among the approaches for exploiting nanotechnology in medicine, nanoparticles off er some unique advantages as sensing, image enhancement, and delivery agents. Several varieties of nanoparticles with biomedical relevance are available including, polymeric nanoparticles, metal nanoparticles, liposomes, micelles, quantum dots, dendrimers, and nanoassemblies. To further the application of nanoparticles in disease diagnosis and therapy, it is important that the systems are biocompatible and capable of being functionalized for recognition of specifi c target sites in the body after systemic administration. In this review, we have explained some important applications of gold nanoparticles.

Measurement of thermal conductivity of ZnO–TiO 2 /EG hybrid nanofluid

Abstract: The hybrid nanofluids are novel nanofluids and can be prepared by suspending various kinds of nanoparticles in base fluid. In this paper, an experimental investigation on the effects of temperature and nanoparticles concentration on the thermal conductivity of ZnO–TiO2/EG hybrid nanofluids is presented. The experiments were implemented at temperature ranging from 25 to 50 °C and solid volume fraction range of 0–3.5 %. Experiments indicate that the thermal conductivity enhances with increasing the solid volume fraction and temperature. It was found that the variation of thermal conductivity enhancement of nanofluids with solid volume fraction at higher temperatures is greater than that at lower temperature. Moreover, it can be also seen that the variation of thermal conductivity enhancement of nanofluids with temperature at higher solid volume fraction is more than that at lower solid volume fraction. Finally, based on experimental data, in order to predict the thermal conductivity ratio of ZnO–TiO2/EG hybrid nanofluids, a correlation was proposed. Deviation analysis of the thermal conductivity ratio was also performed. Comparison between experimental data and the proposed correlation outputs revealed that this correlation has a good accuracy.

A GIS-based flood susceptibility assessment and its mapping in Iran: a comparison between frequency ratio and weights-of-evidence bivariate statistical models with multi-criteria decision-making technique

Abstract: Flood is one of the most prevalent natural disasters that frequently occur in the northern part of Iran reported in hot spots of flood occurrences The main aim of the current study was to prepare flood susceptibility maps using four models, namely frequency ratio (FR), weights-of-evidence (WofE), analytical hierarchy process (AHP), and ensemble of frequency ratio with AHP (FR-AHP), and to compare them at Haraz Watershed in Mazandaran Province, Iran A total of 211 flood locations were prepared in GIS environment, of which 151 locations were randomly selected for modeling and the remaining 60 locations were used for validation aims In the next step, 10 flood-conditioning factors were prepared including slope angle, plan curvature, elevation, topographic wetness index, stream power index, rainfall, distance from river, geology, landuse, and normalized difference vegetation index The receiver operating characteristic curve and the area under the curve (AUC) were created for different flood susceptibility maps Validation of results showed that AUC values for success rate in training data set, for FR, WofE, AHP, and FR-AHP, were 9707, 9896, 9591, and 8619 % with prediction rates of 09657 (9657 %), 09596 (9596 %), 09492 (9492 %), and 08469 (8469 %), respectively Moreover, the results showed that the frequency ratio model had the highest AUC in comparison with other models Generally, the four models show a reasonable accuracy in flood-susceptible areas The results of this study can be useful for managers, researchers, and planners to manage the susceptible areas to flood and reduce damages

Optimization of neural networks for precipitation analysis in a humid region to detect drought and wet year alarms

Abstract: In this study, annual precipitation was forecast by coding in MATLAB software environment based on a non-linear autoregressive neural network (NARNN), non-linear input–output (NIO) and NARNN with exogenous input (NARNNX). Historical precipitation data (27 precipitation gauge stations located in Gilan, Iran) were used as two 21 year sets from 1968 to 1988 and from 1989 to 2009 for calibration and testing of the networks, respectively. Results showed that the accuracy of the NARNNX was better than that of the NARNN and NIO, based on r values. However, performance of the networks was not satisfactory because the number of neurons in the hidden layer and the roles of training, validation and testing phases were lacking flexibility and change. Optimization of the number of neurons in the hidden layer and the determination of the best role among the different phases led to improvement of network accuracy. The r values were <0.73 only for five stations in the optimized NARNN and <0.74 only for those stations with optimized NIO.

Photo-degradation of organic dyes: simple chemical synthesis of Ni(OH)2 nanoparticles, Ni/Ni(OH)2 and Ni/NiO magnetic nanocomposites

Abstract: In this work Ni, Ni(OH)2, NiO nanoparticles as well as Ni/Ni(OH)2 and Ni/NiO nanocomposites were synthesized via a simple chemical precipitation method in aqueous solution. The prepared products were characterized by X-ray diffraction pattern (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR) spectroscopy. Alternating gradient force magnetometer (AGFM) illustrated ferro-magnetic behaviour of Ni nanoparticles as well as Ni/Ni(OH)2 and Ni/NiO nanocomposites. The photocatalytic behaviour of Ni–NiO nanocomposites was evaluated using the degradation of organic dyes under ultraviolet light irradiation. The results show that Ni–NiO nanocomposites have applicable magnetic and photocatalytic performance.

Temperature-Responsive Smart Nanocarriers for Delivery Of Therapeutic Agents: Applications and Recent Advances

Abstract: Smart drug delivery systems (DDSs) have attracted the attention of many scientists, as carriers that can be stimulated by changes in environmental parameters such as temperature, pH, light, electromagnetic fields, mechanical forces, etc. These smart nanocarriers can release their cargo on demand when their target is reached and the stimulus is applied. Using the techniques of nanotechnology, these nanocarriers can be tailored to be target-specific, and exhibit delayed or controlled release of drugs. Temperature-responsive nanocarriers are one of most important groups of smart nanoparticles (NPs) that have been investigated during the past decades. Temperature can either act as an external stimulus when heat is applied from the outside, or can be internal when pathological lesions have a naturally elevated termperature. A low critical solution temperature (LCST) is a special feature of some polymeric materials, and most of the temperature-responsive nanocarriers have been designed based on this feature. In...

Application of magnetic nanoparticles in smart enzyme immobilization.

Abstract: Immobilization of enzymes enhances their properties for efficient utilization in industrial processes. Magnetic nanoparticles, due to their high surface area, large surface-to-volume ratio and easy separation under external magnetic fields, are highly valued. Significant progress has been made to develop new catalytic systems that are immobilized onto magnetic nanocarriers. This review provides an overview of recent developments in enzyme immobilization and stabilization protocols using this technology. The current applications of immobilized enzymes based on magnetic nanoparticles are summarized and future growth prospects are discussed. Recommendations are also given for areas of future research.

Recent advances and emerging challenges in microbial electrolysis cells (MECs) for microbial production of hydrogen and value-added chemicals

Abstract: Microbial electrolysis cell (MEC) is a potentially attractive green technology to tackle the global warming and energy crisis, which employs electrochemically active bacteria to convert organic matter into hydrogen or a wide range of chemicals, such as methane, acetate, hydrogen peroxide, ethanol, and formic acid, without causing environmental pollution. Until now, probably the cleanest and the most efficient method of producing hydrogen has been MEC. However, this technology is still in its infancy period and poses various challenges towards up-scaling and widespread applications, such as such as lower hydrogen production rate (HPR), high internal resistance, complicated architecture, and expensive materials. New advances are needed in biofilm engineering, materials for electrodes and reactor configuration for successful real-world application of this technology. Thus, the present review deals with development of practical MEC technology and includes the following sections: firstly a general introduction to MECs; their operating principles, thermodynamics of MEC, and energy or voltage losses in the MEC system were provided. Followed by a section on the critical factors affecting MEC performance; microorganisms, anode, cathode, membrane or separator, fuel sources, the state-of-art MECs designs, other key operational factors, and its potential application in microbial production of value added products are discussed in detail. Afterwards, current challenges involved in developing practical MEC systems are highlighted, and outlooks for future development are also suggested. The review aims to assist researcher and engineers to gain fundamental understandings of MEC, and it also provides several future research directions and a road map on how to overcome the barriers, so the MEC technology can be further advanced and applied in larger scale.

Ionic Reactivity at Contacts and Aging of Methylammonium Lead Triiodide Perovskite Solar Cells

Abstract: Hybrid lead halide perovskites have reached very la ge solar to electricity power conversion efficiencies, even in some cases exceedi ng 20%. The most extensively used perovskite-based solar cell configuration comprises CH3NH3PbI3 (MAPbI3) in combination with electron (TiO 2) and hole 2,2 ′,7,7′-tetrakis(N,N-di-pmethoxyphenylamine)-9,9-spirobifluorene ( spiro-OMeTAD) selective contacts. The recognition that the solar cell performance is heav ily affected by time scale of the measurement and preconditioning procedures has rais ed many concerns about the stability of the device and reliability for long ti me operation. Mechanisms at contacts originate observable current-voltage distortions. T wo types of reactivity sources have been identified here: ( i) weak Ti−I−Pb bonds that facilitate interfacial ac commodation of moving iodine ions. This interaction produces a highly reversible capacitive current originated at the TiO2/MAPbI3 interface, and it does not alter steady-state phot ovoltaic features. ( ii ) An irreversible redox peak only observable after positive poling at slow scan rates. It corresponds to the chemical reaction between spiro-OMeTAD and migrating I which progressively reduces the hole transporting material conductivity and deteriorates solar cell performance.

Review for application of electrospinning and electrospun nanofibers technology in textile industry

Abstract: Electrospinning (electrostatic fiber spinning) is a modern and efficient method which uses electric field to produce fine fibers which their diameter can reduce to nanometers. These fibers have wide applications in industry such as filtration, composite materials, medical, membrane, etc. In this paper a review of electrospinning process, its products and applications are explained.

Study of nanoparticles aggregation/agglomeration in polymer particulate nanocomposites by mechanical properties

Abstract: A simple approach is described to study the aggregation/agglomeration details in polymer nanocomposites reinforced with spherical nanoparticles. The suggested methodology for mechanical properties can offer the aggregation/agglomeration level as a function of different parameters. In addition, the effective volume fraction of agglomerated nanoparticles in nanocomposite samples ( ϕ agg ) is determined by the present technique. The calculated results for various samples express that the aggregation/agglomeration of nanoparticles is occurred in all reported nanocomposites. Also, both aggregate/agglomerate and nanofiller diameters play important roles in aggregation/agglomeration level of samples. The aggregation/agglomeration extent increases by addition of nanofiller content and reduction of nanofiller size. Moreover, the aggregation/agglomeration decreases the effectiveness of nanoparticles in polymer matrix, which lastly results in the poor properties of samples.

Gas sensor based on MoS2 monolayer

Abstract: We investigate the electronic and transport properties of a MoS 2 monolayer transducer with some simple gas molecules, such as CO, CO 2 and NO to explore theoretically sensing capabilities of this monolayer. The calculations are performed using nonequilibrium Green's function (NEGF) formalism based on the density functional theory (DFT) as implemented in the TranSIESTA code. Exposure to the NO gas molecule influences dramatically the electron transmission and the current–voltage characteristics of the MoS 2 monolayer. The results predict that the MoS 2 monolayer transducer can monitor the NO gas molecule to 10 4 order among these molecules between ±0.9 V bias window using the current–voltage characteristic with high sensitivity and selectivity. Here, post-processed analyses predict that the sensing mechanism is based on the charge transfer, which it in turn causes remarkable electrostatic gating to occur for the NO adsorbate. The numerical results may be useful to engineer and design gas sensor based on the MoS 2 monolayer.

Potential of biogas production from farm animal waste in Malaysia

Abstract: Anaerobic digestion of renewable feedstocks has been known as a prospective technology for the production of clean energy in the form of biogas. Biogas is a sustainable energy carrier which is mainly composed of methane (60%) and carbon dioxide (35–40%). Among the raw substances, organic matters obtained from farm animal waste are pivotal sources for biogas production. In recent years, the number of animal husbandry has drastically grown in Malaysia. Accordingly, a large amount of animal waste including manure, blood and rumen content are produced which provide a tremendous source of biogas generation. This paper presents biogas potential from the organic waste obtained from the farm animals and slaughterhouses in Malaysia. The findings of this study indicated that biogas potential of 4589.49 million m 3 year − 1 could be produced from animal waste in Malaysia in 2012 which could provide an electricity generation of 8.27×10 9 kWh year −1 .

Study on the removal of heavy metal ions from industry waste by carbon nanotubes: Effect of the surface modification: a review

Abstract: Removal of noxious materials such as heavy metal ions (which are hazardous above certain ppm concentration) from wastewater is one of the biggest environmental challenges that suffers the economy nowadays. On the basis of their versatility, environmental friendliness, the adsorption was proved to be a most economical and efficient technology, which is used extensively for their removal from the aqueous media. Among the various developed adsorbents used so far, carbon nanotubes (CNTs) show a unique impact on the fast adsorption and rapid removal of noxious impurities from the aqueous source. CNTs festooned on the sources like activated carbon, nanoparticles, and nanocomposities enhanced the efficiency and potential of the adsorbent. Due to their unique structural, electronic, optoelectronic, semiconductor, as well as mechanical, chemical, and physical properties, they have been extensively used to remove heavy metals in wastewater treatment. The adsorption mechanisms are majorly contributed by the ...