Sharif Digital Repository

In this paper, a new software is introduced that is developed to give the most appropriate solution for the component selection and design of a hybrid electric bus. There are several simulation programs that can simulate behavior of a hybrid electric bus, but most of them are not able to suggest the best design and the best choice of the components. Customer requirements are dissimilar and there are several different parameters that they may need. Cost, pollution, driving cycle, battery type, DC link voltage, weight, volume, fuel consumption, and acceleration are some parameters that vary from one customer to the other. The stated software that is developed and presented by this paper will... 

This chapter reviews the recent advances in two-dimensional hexagonal boron nitride-based electrochemical sensors. Hexagonal boron nitride nanosheets are lesser utilized than other 2D nanostructures in electrochemistry and electrochemical sensing due to their unsuitable electrical conductivity. Recent studies have determined that high specific surface area, the presence of many active edges, the possibility of tunning the bandgap through interactions with other nanomaterials, and chemical motifs result in enhanced catalytic activity and conductivity. Therefore, 2D h-BN becomes a promising modifier for electroanalytical sensing applications. Herein, we present the recent progress in 2D... 

Kinetics and isotherms of adsorption behavior of nanoscale Zr-based metal-organic framework for the removal of three organic dyes including acidic, direct and basic ones from aqueous solutions were studied by sorption models. Nanocube-shaped UiO-66 particles with an average edge length of 215 nm, specific surface area of 1215 m2/g, total pore volume of 0.58 cm3/g, and average pore diameter of 1.8 nm were prepared by solvothermal methods. Analyzing of the equilibrium isotherms indicates that direct dye removal is best fitted with the Langmuir isotherm. Study of the adsorption kinetics also determines that direct dye adsorption follows pseudo-first-order model (R2=0.99). The kinetics of basic... 

Activated carbon (AC) is an inert adsorbent material that has widely been used in water treatment or removing of environmental pollutants from water. In order to improve the adsorption of AC, which highly depends on its pore size and surface area, we prepared highly porous adsorbent composites of activated carbon (AC)/chromium-based MOF (MIL-101(Cr)). The composite has a high specific surface area of 2440 m2 g−1 and total pore volume of 1.27 cm3 g−1. To show the efficiency of the composite as an adsorbent, the removal kinetics of anionic dyes (Direct Red 31 and Acid Blue 92) from aqueous solutions dependent on the amount of composite, adsorption time, concentration of dye and pH is... 

The potential of carbon-based nanosheet membranes with functionalized pores is great as water treatment membranes. Using the molecular dynamic simulation technique, the dimethyl sulfoxide (DMSO) separation from the water/DMSO binary solution is investigated, and the functionalized graphene nanosheets are used as a membrane. This membrane was functionalized by –F (fluorine) and –H (hydrogen) functional groups. For the separation of DMSO, external hydrostatic pressures up to 100 MPa were applied to the considered systems. The separation mechanism was based on molecular size. Multiple analyses were done to study the capability of considered membranes for the separation of DMSO molecules from... 

Electrospun nanofibers have several uses. They are one of the safest nanomaterials because of their long lifetime. Polymeric and nonwoven membranes cannot match their surface-to-volume ratio, porosity, and flexibility, which are unrivaled by their traditional alternatives. Gas separation is a common industrial procedure. Commercial exhausts and routine activities may produce air pollution. Researchers have found environmental protection or governance opportunities using electrospun nanofibers with a high specific surface area, especially for fast gas pollutant collection. Here is a look at recent breakthroughs in electrospun nanofibers for gas filtration. The history and design principles of... 

In this paper, a novel droop method to control the power sharing of parallel uninterruptible-power-supply (UPS) systems is presented. In a clear-cut contrast to the previously reported works, the controller is a proportional-resonant controller which ensures good transient response and steady-state objectives. Furthermore, the need for sensing the output current for the power-sharing control is removed by implementing it in a software routine. This brings a less complicated and less expensive structure in which the number of feedback sensors is reduced from three to two. The droop paralleling strategy is based on the drop in the inverter output frequency and amplitude. The application of... 

Promising properties of boron nitride nanomaterials such as their chemical, thermal, and mechanical stability have made them suitable materials in a various range of applications. However, their low electrical conductivity and wide bandgap, particularly in the case of boron nitride quantum dots (BNQDs), have given rise to severe limitations. Efforts on bandgap engineering through doping and surface functionalization have gained little success due to their high thermodynamic stability and inertness. Herein, we present a novel approach to functionalize BNQDs by hydroxyl, methyl, and amine functional groups aiming to adjust the electronic structure. The successful exfoliation is demonstrated by... 

Comparative studies between response surface methodology (RSM) and artificial neural network (ANN) methods to find the effects of electrospinning parameters on the porosity of nanofiber mats is described. The four important electrospinning parameters studied included solution concentration (wt.%), applied voltage (kV), spinning distance (cm) and volume flow rate (mL/h). It was found that the applied voltage and solution concentration are the two critical parameters affecting the porosity of the nanofiber mats. The two approaches were compared for their modeling and optimization capabilities with the modeling capability of RSM showing superiority over ANN, having comparatively lower values of... 

Clustering-based image segmentation is a well-known multispectral image segmentation method. However, as it inherently does not account for the spatial relation among image pixels, it often results in inhomogeneous segmented regions. The recently proposed membership-connectedness (MC)-based segmentation method considers the local and global spatial relations besides the fuzzy clustering stage to improve segmentation accuracy. However, the inherent spatial and intraclass redundancies in multispectral images might decrease the accuracy and efficiency of the method. This letter addresses these two problems and proposes a segmentation method that is based on the MC method, watershed transform,... 

In this paper, a simpler implementation of the well-known droop method for the control of parallel Uninterruptible Power Supply (UPS) systems is presented. In this method, in the power-sharing control scheme, the output current is calculated by software without the need for a current sensor, resulting in a simpler and cheaper structure. By doing so, the number of feedback sensors is reduced from three to two. The paralleling strategy uses the droop method in which the control strategy is based on the drop in the inverter output frequency and amplitude. The application of Proportional-Resonant (PR) controllers is also extended to parallel inverter and its superior performance over the... 

Magnetic resonance imaging (MRI) techniques provide detailed anatomic information non-invasively and without the use of ionizing radiation. The development of new pulse sequences in MRI has allowed obtaining images with high clinical importance and thus joint analysis (multispectral MRI) is required for interpretation of these images. Fuzz rule-based systems can combine many inputs from widely varying sources so that they can be useful for description of tissues in MRI. In a fuzzy system an error free and optimized classifier can be obtained by genetic algorithms. In this paper, we have utilized a genetic fuzzy system for modeling different tissues in brain MRI and proposed a statistical... 

Scour is an important cause of instability of breakwaters. In case of vertical-wall breakwaters, toe scour can cause collapse of the whole structure. This paper is concerned with an experimental study of the effects of regular breaking waves on scour at toe of vertical-wall breakwaters. Experiments were carried out in a wave flume with regular waves for two cases of a beach with and without a breakwater. Bed profiles and scour depths for various wave heights, periods and depths were recorded. For the case of a beach without a breakwater, the observed bed profile types are compared to predictions. For the case of a beach with a breakwater, factors affecting the scour are investigated, and an... 

During the last decade, solution-processed colloidal quantum dots (CQDs) have attracted significant attention for low-cost fabrication of optoelectronic devices. In this study, lead sulfide (PbS) CQDs were synthesized via the hot injection method and the effect of doping elements with low electron affinity, including cadmium, calcium and zinc, on the passivation of trap states was investigated. A red-shift in the luminescence emission was observed by doping through passivation of lead dangling bonds. Time-resolved photoluminescence measurements showed that the lifetime of charged carriers was significantly enhanced by cadmium doping (∼80%) which is quite noticeable compared with calcium- and... 

Decreasing Drain-Induced-Barrier-Lowering (DIBL) is one of the nondesirable short-channel effects, causes the threshold voltage of the transistor to be reduced by increasing the drain voltage. DIBL makes it impossible for engineers to consider VT as a constant, and it is necessary to calculate VT as a function of the drain voltage. Therefore, to consider the DIBL effect in the design of ICs, a large computational burden is imposed on the system, which slows down the simulation process in circuit-level simulators. Accordingly, a Nonlinear Feed-Forward Memory-Less (NFFML) model using the Gram-Schmidt orthogonalization approach is proposed, which calculates the VT of the new generation of... 

The α-FAPbI3 perovskite nanocrystals exhibit interesting optical properties, which make them attractive for versatile optoelectronic applications; however, the spontaneous phase transformation to the non-perovskite phase (δ-FAPbI3) in humid conditions requires a new strategy to improve the phase stability of the material. We employed 3-Aminopropyl triethoxysilane (APTES)-assisted reprecipitation and sol-gel methods at ambient temperature to prepare stable α-FAPbI3 nanocrystals embedded in a silica matrix. Transmission electron microscopy (TEM) and X-ray diffraction analysis determined that ultrafine perovskite nanocrystals (11.5 ± 3 nm) were uniformly distributed in a silica matrix.... 

Moving from two-dimensional hexagonal boron nitride (2D h-BN) flatlands towards their quantum sized zero-dimensional (0D) islands, as the newest member of the h-BN family, has recently opened up novel research areas due to the emergence of unique optical and physicochemical properties, excellent thermal and chemical stability, and desirable biocompatibility. This review elaborates on the fundamental properties of 2D and 0D h-BN nanomaterials and covers the latest progress in the fabrication and applications of BN nanosheets (BNNSs) and quantum dots (BNQDs). Initially, the transformation of properties in h-BN nanomaterials is discussed when moving from the 2D realm towards the 0D quantum...