Synthesis and corrosion protection study of poly(o-ethylaniline) coatings on copper

Poly(o-ethylaniline) coatings were synthesized on copper (Cu) by electrochemical polymerization of o-ethylaniline in an aqueous salicylate solution by using cyclic voltammetry. The characterization of these coatings was carried out by cyclic voltammetry, UV-visible absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The results of these characterizations indicate that the aqueous salicylate solution is a suitable medium for the electrochemical polymerization of o-ethylaniline to generate strongly adherent and smooth poly(o-ethylaniline) coatings on Cu substrates. The performance of poly(o-ethylaniline) as protective coating against corrosion of Cu in aqueous 3% NaCl was assessed by the potentiodynamic polarization technique and electrochemical impedance spectroscopy (EIS). The results of these studies demonstrate that the poly(o-ethylaniline) coating has ability to protect the Cu against corrosion. The corrosion potential was about 0.078 V versus SCE more positive in aqueous 3% NaCl for the poly(o-ethylaniline) coated Cu (∼ 15 μm thick) than that of uncoated Cu and reduces the corrosion rate of Cu almost by a factor of 70.     

Triplet Harvesting with 100% Efficiency by Way of Thermally Activated Delayed Fluorescence in Charge Transfer OLED Emitters

Organic light‐emitting diodes (OLEDs) have their performance limited by the number of emissive singlet states created upon charge recombination (25%). Recently, a novel strategy has been proposed, based on thermally activated up‐conversion of triplet to singlet states, yielding delayed fluorescence (TADF), which greatly enhances electroluminescence. The energy barrier for this reverse intersystem crossing mechanism is proportional to the exchange energy (ΔE_ST) between the singlet and triplet states; therefore, materials with intramolecular charge transfer (ICT) states, where it is known that the exchange energy is small, are perfect candidates. However, here it is shown that triplet states can be harvested with 100% efficiency via TADF, even in materials with ΔE_ST of more than 20 kT (where k is the Boltzmann constant and T is the temperature) at room temperature. The key role played by lone pair electrons in achieving this high efficiency in a series of ICT molecules is elucidated. The results show the complex photophysics of efficient TADF materials and give clear guidelines for designing new emitters.     

Green's Function for Transversely Isotropic Thermoelastic Diffusion Bimaterials

The aim of the present article is to study the Green's function in transversely isotropic thermoelastic diffusion bimaterial. With this objective, first the three-dimensional general solution in transversely isotropic thermoelastic diffusion bimaterial is derived. On the basis of general solution, Green's function, with a concentrated heat source in steady state, is completely solved using harmonic functions. The components of displacement, stress, temperature distribution, and mass concentration are expressed in terms of elementary functions. The resulting quantities are computed numerically and illustrated graphically. A particular case of three-dimensional Green function in transversely isotropic thermoelastic bimaterial has been deduced from the present investigation.     

Modeling multilayered MEMS-based micro-fluidic systems

This article describes the design, fabrication, and simulation of two micro-electromechanical systems-based micro-fluidic systems. The first system, a lab-on-a-chip, enables electrochemical immunoassay-based chemical/biological detection. The second is a micro-fluidic bio-impedance sensor. The relevance of fluidic dynamics in micro-fluidic channels is discussed in context of fluid paths and misalignments in the channels that appear during multi-level structure integration. Also discussed is the effect of channel dimensions on the flow profile and on performance within the micro-systems. For more information, contact Shekhar Bhansali, University of South Florida, Nanomaterials and Nanomanufacturing Research Center, Department of Electrical Engineering, 4202 East Fowler Avenue ENB 118, Tampa, Florida 33620; e-mail bhansali@eng.usf.edu.     

Structural and dielectric properties of a novel Bi2O3-(1 −x)WO3-xCuO solid solution

A novel solid solution in the system Bi-W-Cu-O has been synthesized and its structural and dielectric properties studied. The solid solution Bi₂O₃-(1 −x)WO₃-xCuO exists up tox=0·7; the solid solutions up tox=0·65 are orthorhombic but stabilize in tetragonal structure in a narrow range aroundx=0·7. The solid solutions are non-centrosymmetric and exhibit ferroelectric behaviour similar to their parent phase Bi₂WO₆. The Curie point of the solid solution is found to decrease with increase inx.     

Interpolymer association between phenolic copolymers and polyelectrolytes: effects of copolymer structure and hydrophobic interactions on the stability of polycomplexes

Summary Phenolic copolymers have been prepared with two different feed compositions from some typical phenolic monomers, such as, p-Chlorophenol, p-Cresol and p-Aminophenol. They have been characterized by known methods. Some interpolymer complexes of the phenolic copolymers have been prepared with polyelectrolytes, such as poly(methacrylic acid) (PMA) and poly(ethylene imine)(PEI). The degree of linkage, stability constant, enthalpy and entropy changes of the systems were determined at several temperatures. Interpretations have been sought in terms of the various interacting forces involved in the complex formation.     

Semi-Markov modeling of dependability of VoIP network in the presence of resource degradation and security attacks

Nowadays VoIP has become an evolutionary technology in telecommunications. Hence it is very important to study and enhance its dependability attributes. In this paper, an analytical dependability model for VoIP is proposed. The study is focused on analyzing the combined effects of resource degradation and security breaches on the Quality of Service (QoS) of VoIP, to enhance its overall dependability. As a preventive maintenance policy to prevent or postpone software failures which cause resource degradation, software rejuvenation is adopted. The dependability model is analyzed using semi-Markov process which captures the effects of non-Markovian nature of the time spent at various states of the system. The steady-state as well as the time-dependent analysis of the dependability model is presented. The steady-state results are obtained analytically, whereas the time-dependent results are obtained from simulation. Also, the analytical model is validated via simulation. The model analysis using a numerical example indicates the feasibility of our approach. Various dependability attributes such as availability, reliability and confidentiality are also obtained. A comparative study is also done between our proposed model and the existing models.     

An efficient elite group-based routing protocol for wireless sensor network

ABSTRACT

In recent days, due to the wide verities of applications of Wireless Sensor Networks, it gets recognition from research communities. As the sensor nodes are operated through limited battery capacity, how to utilise the battery power or energy in an optimum way is a major concern. In this paper, we have addressed the energy issue of wireless sensor networks. We have developed an energy-efficient routing protocol. This paper proposes the Novel Elite group concept where the cluster-head selection process is restricted to only a few high-energy nodes rather than all nodes in the network, which substantially reduces the number of cluster-head selection overhead in every iteration, decreases the energy consumption and increases network lifetime. Our method is compared with three well-known routing protocols, i.e. EECRP (Energy Efficient Centroid-Based Routing Protocol) protocol, NCBR (New Cooperative Balancing Routing Protocol) and Mod-LEACH (Modified low-Energy Adaptive Clustering Hierarchy Protocol). We have conducted a simulation in NS-2 simulator. We have computed various network quality parameters like Throughput, transmission delay, analysis of the number of dead nodes (reciprocal of alive nodes) and energy dissipation with respect to the number of simulation rounds. The simulation results show that our proposed methodology outperforms the rest of the protocol.     

Macroporous WO3: Tunable morphology as a function of glycine concentration and its excellent acetone sensing performance

Materials-by-Design symbolizes the development of advanced materials with cost and time -effective experimentation. Here, we show the single and unique strategy of developing macroporous WO₃ with different morphologies (nano to micro) using glycine as structure assisting agent. The developed structures were analyzed with various characterizing tools, and tested for practical application as acetone gas sensor (83.87% for 10?ppm). The morphological correlation with the sensitivity is described.     

Detection of SARS-CoV-2 using dielectric modulated TFET-based biosensor

Journal of Materials Science: Materials in Electronics - Attributable to the rapid increase in human infection of Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome...