Experimental evaluation of the interfacial properties of carbon nanotube coated carbon fiber reinforced hybrid composites

A floating catalyst chemical vapor deposition (CVD) unit was utilized to grow CNT onto the surface of carbon fiber (CF). The surface morphology of the resultant fibers, CNT population density and alignment pattern were found to be depended on the CNT growth temperature, growth time, and atmospheric conditions within the CVD chamber. In contrast to the neat‐CF reinforced composites, improved interfacial shear strength (IFSS) between CF and matrix were obtained when the surface of CF was coated by CNT. Particularly, CF treatment condition for CNT‐coating with 700°C reaction temperature and 30 min reaction time has shown a considerable increase in IFSS approximately of 45% over that of the untreated fiber from which it was processed. The proper justification of fiber–matrix adhesion featured by composite interfacial properties was explained through IFSS. POLYM. COMPOS., 36:1941–1950, 2015. © 2014 Society of Plastics Engineers     

Design of Circular Urban Storm Sewer Systems Using Multilinear Muskingum Flow Routing Method

In this study, a multilinear Muskingum method is presented for hydrologic routing through circular conduits. In order to increase accuracy, the reference discharge is assumed to be a nonlinear function of conduit diameter, Manning coefficient, bed slope, and peak discharge of the inflow hydrograph. The reference discharge function has been determined using a nonlinear regression technique. Flow depths are computed at every time step by solving the continuity equation using an implicit finite difference scheme. Many storm hydrographs were routed through circular conduits of various sizes by the proposed model. The calculated routed hydrographs and water surface profiles indicate close agreement with those obtained by solving Saint Venant equations. Using this method, a branched urban sewer system was designed. This indicates that the method can be easily implemented for design purposes because of its simplicity, accuracy, and computational efficiency.     

Voltammetric studies of a cobalt(II)-4-methylsalophen modified carbon-paste electrode and its application for the simultaneous determination of cysteine and ascorbic acid

A carbon-paste electrode (CPE) chemically modified with the cobalt(II)-4-methylsalophen (CoMSal) as a Schiff base complex was used as a highly sensitive and fairly selective electrochemical sensor for simultaneous determination of minor mounts of ascorbic acid (AA) and cysteine. This modified electrode shows very efficient electrocatalytic activity for anodic oxidation of both AA and cysteine via substantially decreasing of anodic overpotentials for both compounds. The mechanism of electrochemical oxidation of both AA and cysteine using CoMSal-modified electrode was thoroughly investigated by cyclic voltammetry and polarization studies. Results of cyclic voltammetry (CV) and differential pulse voltammetry (DPV) using this modified electrode show two well-resolved anodic waves for the oxidation of AA and cysteine, which makes it possible for simultaneous determination of both compounds. A linear range of 1 × 10⁻⁴ to 5 × 10⁻⁷ M for cysteine in a constant concentration of 1 × 10⁻⁴ M AA in buffered solution (as a background electrolyte) was obtained from DPV measurements using this electrode. The linear range, which is obtained for AA in the presence of 1 × 10⁻⁴ M cysteine, was in the range of 1 × 10⁻⁴ to 1 × 10⁻⁶ M. The modified electrode has good reproducibility (RSD ≤ 2.5%), low detection limit (sub-micromolar) and high sensitivity for the detection of both AA and cysteine with a very high stability in its voltammetric response. Differential pulse voltammetry using the modified electrode exhibited a reasonable recovery for a relatively wide concentration range of cysteine spiked to a synthetic human serum sample.     

被动动态目标操作: 初步定义和例子

In this work, we introduce a category of dynamic manipulation processes, namely passive dynamic object manipulation, according to which an object is manipulated passively. Specifically, we study passive dynamic manipulation here. We define the main concept, discuss the challenges, and talk about the future directions. Like other passive robotic systems, there are no actuators in these systems. The object follows a path and travels along it under the effect of its own weight, as well as the interaction force applied by each manipulator on it. We select some simple examples to show the concept. For each example, dynamic equations of motion are derived and the stability of the process is taken into account. In this direction, some rules are derived under which we ensure that the manipulation process does not fail. Simulations support this idea.     

A Unified Optimization-Based Framework to Adjust Consensus Convergence Rate and Optimize the Network Topology in Uncertain Multi-Agent Systems

This paper deals with the consensus problem in an uncertain multi-agent system whose agents communicate with each other through a weighted undirected (primary) graph. The considered multi-agent system is described by an uncertain state-space model in which the involved matrices belong to some matrix boxes. As the main contribution of the paper, a unified optimization-based framework is proposed for simultaneously reducing the weights of the edges of the primary communication graph (optimizing the network topology) and synthesizing a controller such that the consensus in the considered uncertain multi-agent system is ensured with an adjustable convergence rate. Considering the NP-hardness nature of the optimization problem related to the aforementioned framework, this problem is relaxed such that it can be solved by regular LMI solvers. Numerical/practical-based examples are presented to verify the usefulness of the obtained results.      

Dielectric relaxation and conduction behaviors of Aurivillius Na0.5Bi4.5Ti4O15 ceramics with Na doping

Aurivillius Na0.5Bi4.5Ti4O15 and Bi4Ti3O12 compounds were synthesized via solid-state reaction tech-nique.X-ray powder diffraction study confirmed monophasic fo...     

What is the relationship between research funding and citation-based performance? A comparative analysis between critical disciplines

Scientometrics - The goal of the study here is to model and analyze the relation between research funding and citation-based performance in science to predict the diffusion of new scientific...     

Utilization of a triple hexagonal split ring resonator (SRR) based metamaterial sensor for the improved detection of fuel adulteration

Journal of Materials Science: Materials in Electronics - In this work, a triple hexagonal split ring resonator incorporated metamaterial sensor is proposed for the improved detection of fuel...     

Use of silver nanoparticles as an electron transfer facilitator in electrochemical ligand-binding of haemoglobin

Silver nanoparticles have an activity for high intensity electron transfer. They can facilitate the electron transfer from the redox centre of a protein, as a high volume molecule, to the electrode surface. In this study, silver nanoparticles were deposited on the surface of a graphite carbon electrode in the 1 V potential region. Deposition of silver nanoparticles, with a diameter between 70 and 150 nm, was observed on the graphite electrode by transmission electron microscopy (TEM). The results demonstrated that the fine redox waves of haemoglobin could be achieved after modification of the graphite electrode by silver nanoparticles. The cathodic and anodic peaks of haemoglobin were at −135 and +375 mV vs. Ag/AgCl, respectively. The effect of guanosine 3′,5′-triphosphate (GTP), guanosine diphosphate (GDP) and guanosine monophosphate (GMP) on the structure of haemoglobin was investigated. It was observed that GTP shifts the cathodic and anodic peaks positively, indicating the transfer of the haem group to the surface of protein as a reflex of easier oxidation and reduction, while GDP and GMP do not show this behaviour. GTP binds with haemoglobin, while GDP and GMP do not.     

Rainfall-runoff Modeling in a Watershed Scale Using an Object Oriented Approach Based on the Concepts of System Dynamics

Relying on a linear causal thinking, most of the hydrological models fail to incorporate socio-economic characteristics of a watershed with hydrological and environmental attributes. Based on a systems thinking philosophy, the paper aims to adopt an Object-Oriented (OO) approach based on the concepts of System Dynamics (SD) such as stocks and flows to analyze the dynamics in a hydrological system in a watershed scale. Object-Oriented modeling is a way to organize data into discrete, recognizable entities called objects. These objects could be concrete (such as a river reach) or conceptual (such as a policy decision). In the present paper, VENSIM PLE has been used for the modeling purpose. The application was illustrated in an Iranian watershed. The model was examined using validity and verifying tests. The results showed that the model is capable of generating the monthly runoff quite well. The values of R² are 0.69 and 0.61 for generated discharge values at Polchehr and Doab stations respectively. Also the values of NSE are 0.66 and 0.64 for estimated discharge values at the same stations. The capability of model was more clarified comparing R² and NSE coefficients obtained by a SWAT model with those obtained by Watershed Hydrological Model developed in this study.