Sharif Digital Repository

This review paper delves into the remarkable realm of MXene/carbon hybrid nanostructures within the context of electrochemical energy storage (EES) devices, exploring both the aspirations and realities of their application. The physicochemical attributes of MXenes are clarified, emphasizing the distinctive properties that render them promising candidates in energy storage systems. The synthesis methodologies of MXenes, including heteroatom-doped MXene-based materials and MXene-carbon composites, are expounded. This includes a comprehensive overview of the diverse strategies employed to engineer these hybrid structures. Focusing on energy storage applications, the intriguing domain of... 

Iodic acid supported on wet silica gel and K10 clay are used for the efficient oxidation of benzylic alcohols under microwave irradiation and solvent free condition  

Graphitic carbon nitride (g-CN) is a promising metal-free catalyst for environmental remediation. However, its practical applications have been limited due to insufficient solar-light responsivity. Hetero-element doping and the construction of heterostructures, comprised of g-CN and other band-matched semiconductors could be considered to overcome these drawbacks. In the present work, a series of 2D/3D heterostructures comprised of a few layers of boron-doped g-CN (B-CN) anchored on sea urchin-like Bi2S3 (BS) particles (B-CN@BS) were successfully synthesized. The catalytic performances of B-CN@BS composites were assessed for the photo-reduction of Cr(VI) and in-situ generation of H2O2 under... 

A comprehensive approach is proposed to manage landing sequences and their associated trajectories for an arbitrary number of aircraft in the vicinity of a controlled aerodrome. The current approach, similar to that of "first come, first served," could consider different types of priorities as well as emergencies. The approach is especially useful to combine unstructured free-flight trajectories with structured ones during the approach phase of the flight A comprehensive cost function considers the relative size of all aircraft together with their relative speeds and flight directions. This helps optimize the amount of fuel consumption while respecting separation minima. Resulting... 

4-Amino-2-chloroperbenzoic acid supported on silica gel was found to be a versatile and efficient oxidant for the oxidation of aldehydes and ketones to the corresponding carboxylic acids and esters. Copyright © Taylor & Francis, Inc  

Microvascular anastomosis is a common part of many reconstructive and transplant surgical procedures. While venous anastomosis can be achieved using microvascular anastomotic coupling devices, surgical suturing is the main method for arterial anastomosis. Suture-based microanastomosis is time-consuming and challenging. Here, dissolvable sugar-based stents are fabricated as an assistive tool for facilitating surgical anastomosis. The nonbrittle sugar-based stent holds the vessels together during the procedure and are dissolved upon the restoration of the blood flow. The incorporation of sodium citrate minimizes the chance of thrombosis. The dissolution rate and the mechanical properties of... 

In Industry 4.0, the emergence of new information technology and advanced manufacturing technology (e.g., digital twin, and robot) promotes the flexibility and smartness of manufacturing systems to deal with production task fluctuation. Digital twin-driven manufacturing system with human-robot collaboration is a typical paradigm of intelligent manufacturing. When production task changes, manufacturing system reconfiguration with dynamic opeartion task allocation between operator (human) and robot is a key manner to maintain the production efficiency of intelligent manufacturing system with human-robot collaboration. However, the differences between operator and robot are neglected during... 

A large number of treatment approaches have been used for spinal cord injury improvement, a medically incurable disorder, and subsequently stem cell transplantation appears to be a promising strategy. The main objective of this study is to ascertain whether combinational therapy of human neural stem cells (hNSCs) together with lithium chloride improves cell survival, proliferation, and differentiation in a rat spinal contusion model, or not. Contusive spinal cord injury was implemented on Wistar male rats. Experimental groups comprised of: control, hNSCs transplanted, lithium chloride (Li), and hNSCs and lithium chloride (hNSCs + Li). In every experimental group, locomotor activity score and... 

In this study, we reported the preparation of self cross-linked oxidized alginate-gelatin hydrogels for muscle tissue engineering. The effect of oxidation degree (OD) and oxidized alginate/gelatin (OA/GEL) weight ratio were examined and the results showed that in the constant OA/GEL weight ratio, both cross-linking density and Young's modulus enhanced by increasing OD due to increment of aldehyde groups. Furthermore, the degradation rate was increased with increasing OD probably due to decrement in alginate molecular weight during oxidation reaction facilitated degradation of alginate chains. MTT cytotoxicity assays performed on Wharton's Jelly-derived umbilical cord mesenchymal stem cells... 

The problem of aerodynamic shape optimization of unguided projectiles has been investigated. Two stochastic optimization methods have been applied to solve the problem. These include a Genetic Algorithm (GA) and the recently developed Continuous Ant Colony System (CACS), which is based on the well-known Ant Colony Optimization meta-heuristic. The objective function is defined as the summation of normal force coefficients over a set of given flight conditions. An engineering code (EC) is used to calculate the normal force coefficients over the flight conditions. The obtained results of CACS+EC are compared with those of GA+EC, as well as the results of a previous work (GA +AeroDesign). The... 

As machine learning tasks continue to evolve, the trend has been to gather larger datasets and train increasingly larger models. While this has led to advancements in accuracy, it has also escalated computational costs to unsustainable levels. Addressing this, our work aims to strike a delicate balance between computational efficiency and model accuracy, a persisting challenge in the field. We introduce a novel method that employs core subset selection for reweighting, effectively optimizing both computational time and model performance. By focusing on a strategically selected coreset, our approach offers a robust representation, as it efficiently minimizes the influence of outliers. The... 

Hemodialysis is a process in which the blood is resected using a dialysis apparatus and a specific strainer known as dialyzer. Poor nutritional status is common among hemodialysis patients, but only a few studies are found on how hemodialysis is affected by other factors in the local environment. The aim of this study was to find out hemodialysis patients' nutritional status and the factors that influence it. A total of 100 hemodialysis individuals (50 patients and 50 volunteers) was enrolled in this study. Anthropometry and biochemical assays, as well as nutrition assessments, were used as additional evaluation methods. According to multiple linear regression analysis, malnutrition is... 

In spinal cord injuries, axonal regeneration decreases with the activation of astrocytes followed by glial scar formation. Targeting reactive astrocytes has been recently performed by unsafe viral vectors to inhibit gliosis. In the current study, biocompatible polymeric nanoparticles were selected as an alternative for viruses to target reactive astrocytes for further drug/gene delivery applications. Lipopolysaccharide-bonded chitosan-quantum dots/poly acrylic acid nanoparticles were prepared by ionic gelation method to target reactive astrocytes both in vitro and in spinal cord-injured rats. Owing to their biocompatibility and pH-responsive behavior, chitosan and poly acrylic acid were the... 

In this work, new multi-layer nanocomposite coatings comprised of chitosan (CS) nanofibers functionalized using an innovative silver-based metal–organic framework (SOF) were developed. The SOFs were produced via a facile process using green and environmental-friendly materials. The CS-SOF nanocomposites were coated on hierarchical oxide (HO) layers fabricated on titanium substrates by an innovative two-step etching process. X-ray diffraction revealed fruitful production of the SOF NPs and their stable crystalline structure within the nanocomposite coatings. Energy-dispersive x-ray spectroscopy approved uniform SOFs distribution in the CS-SOF nanocomposites. Atomic force microscopy indicated... 

The worldwide menace of antibiotic-resistance bacteria could be weakened by development and utilization of impressive and multi-functional bactericidal materials. In this work, a novel silver-based metal-organic framework (SOF) was synthesized via a facile and environmentally-friendly process. Different amounts of the SOF nanoparticles incorporated in dual nanosized chitosan/bacterial cellulose (CS/BC) fibrous composites to make a hybrid antibacterial porous structure for mimicing the skin extracellular matrix. X-ray diffraction revealed the successful synthesis of the SOF and CS/BC-SOF nanocomposites using green solvents at ambient temperature. Energy-dispersive X-ray spectroscopy confirmed... 

We propose an all-optical arbitration architecture to resolve end-point contention in the optical networks-on-chip. The proposed architecture reduces on-chip optical power and energy losses by 37% and 21%, respectively, compared to Corona's token-based control plane  

Behavior of a screw dislocation inside a nanotube (NT) is considered in the context of surface elasticity. The elastic fields as well as the image force acting over the dislocation are derived and analyzed in detail. In contrast with the result of classical elasticity, the screw dislocation is shown to be repelled by free surfaces and occupy two stable equilibrium positions near them. The image force strongly depends on the NT's inner and outer radii as well as surface elastic characteristics  

In this study, we have experimentally investigated the electrical properties of graphene and its derivatives (Exfoliated graphene, CVD synthesized graphene, graphene oxide and hydrogenated graphene oxide) under uniaxial strain. We have used gauge factor as a common representation of the sensitivity of the strain sensors and found that the hydrogenated graphene oxide shows significantly higher responsivity comparing to other samples under study. Reproducibility, reliability and lack of hysteresis in the responses of the graphene based samples make them a good candidate to be used in the strain sensors. © 2018  

Digital Elevation Models (DEMs) play a significant role in hydraulic modeling and flood risk management. This study initially investigated the effect of Unmanned Aerial Vehicle (UAV) DEM resolutions, ranging from 1 m to 30 m, on flood characteristics, including the inundation area, mean flow depth, and mean flow velocity. Then, the errors of flood characteristics for global DEMs, comprising ALOS (30 m), ASTER (30 m), SRTM (30 m), and TDX (12 m) were quantified using UAV DEM measurements. For these purposes, the HEC-RAS 2D model in steady-state conditions was used to simulate the flood with return periods of 5- to 200 years along 20 km reach of Atrak River located in northeastern Iran.... 

Optimum highway alignment is among the most substantial, but large and complicated topics in transportation area. Infinite number of feasible solutions, numerous local optima and the constrained feature of the problem, associated with complex and mainly non-linear constraints, has put an extra effort into the problem solving process. This paper focuses on solving highway alignment optimization problem using an integrated model of parallel processing and particle swarm optimization algorithm. To achieve this goal, algorithm parallelization is done in synchronous and asynchronous manner. For assessing parallel performance, corresponding indexes are evaluated. SRTM3 databank is used for solving...