Highly‐Cyclable Room‐Temperature Phosphorene Polymer Electrolyte Composites for Li Metal Batteries

Despite significant interest toward solid‐state electrolytes owing to their superior safety in comparison to liquid‐based electrolytes, sluggish ion diffusion and high interfacial resistance limit their application in durable and high‐power density batteries. Here, a novel quasi‐solid Li⁺ ion conductive nanocomposite polymer electrolyte containing black phosphorous (BP) nanosheets is reported. The developed electrolyte is successfully cycled against Li metal (over 550 h cycling) at 1 mA cm^?2 at room temperature. The cycling overpotential is dropped by 75% in comparison to BP‐free polymer composite electrolyte indicating lower interfacial resistance at the electrode/electrolyte interfaces. Molecular dynamics simulations reveal that the coordination number of Li⁺ ions around (trifluoromethanesulfonyl)imide (TFSI^?) pairs and ethylene‐oxide chains decreases at the Li metal/electrolyte interface, which facilitates the Li⁺ transport through the polymer host. Density functional theory calculations confirm that the adsorption of the LiTFSI molecules at the BP surface leads to the weakening of N and Li atomic bonding and enhances the dissociation of Li⁺ ions. This work offers a new potential mechanism to tune the bulk and interfacial ionic conductivity of solid‐state electrolytes that may lead to a new generation of lithium polymer batteries with high ionic conduction kinetics and stable long‐life cycling.     

Discrete Event System Framework for Fault Diagnosis with Measurement Inconsistency: Case Study of Rogue DHCP Attack

Fault detection and diagnosis (FDD) facilitates reliable operation of systems. Various approaches have been proposed for FDD like Analytical redundancy (AR), Principal component analysis (PCA), Discrete event system (DES) model etc., in the literature. Performance of FDD schemes greatly depends on accuracy of the sensors which measure the system parameters. Due to various reasons like faults, communication errors etc., sensors may occasionally miss or report erroneous values of some system parameters to FDD engine, resulting in measurement inconsistency of these parameters. Schemes like AR, PCA etc., have mechanisms to handle measurement inconsistency, however, they are computationally heavy. DES based FDD techniques are widely used because of computational simplicity, but they cannot handle measurement inconsistency efficiently. Existing DES based schemes do not use Measurement inconsistent (MI) parameters for FDD. These parameters are not permanently unmeasurable or erroneous, so ignoring them may lead to weak diagnosis. To address this issue, we propose a Measurement inconsistent discrete event system (MIDES) framework, which uses MI parameters for FDD at the instances they are measured by the sensors. Otherwise, when they are unmeasurable or erroneously reported, the MIDES invokes an estimator diagnoser that predicts the state(s) the system is expected to be in, using the subsequent parameters measured by the other sensors. The efficacy of the proposed method is illustrated using a pumpvalve system. In addition, an MIDES based intrusion detection system has been developed for detection of rogue dynamic host configuration protocol (DHCP) server attack by mapping the attack to a fault in the DES framework.      

Effect of Benzheterazoles on the Micellar Behavior of Sodium Dodecylsulfate in Dimethylsulfoxide: A Conductometric and Spectroscopic Approach

In this article, we report intermolecular interactions in terms of the effect of benzfused heterocyclic compounds, i.e., 2-thioureidobenzimidazole and 2-thioureidobenzoxazole (0.00, 0.01, and 0.05 mol kg⁻¹), on the micellization behavior of sodium dodecylsulphate (SDS) (1–52 mmol kg⁻¹) in dimethylsulphoxide (DMSO) at different temperatures (293.15–313.15 K) through conductometric and spectroscopic investigations. The variation of specific conductance with SDS concentration has been utilized to estimate the critical micelle concentration ( CMC). The above-performed techniques infer that the presence of additives results in a decrease in the CMC values. Various standard thermodynamic parameters such as free energy change (), enthalpy change (), and entropy change () of micellization have been determined using the temperature dependence of CMC. The above calculated parameters and also UV–visible and fluorescence spectroscopy have been used to obtain information regarding the various interactions between the compounds and surfactant aggregates. In addition, an attempt has also been made to examine the minimum inhibitory concentration (MIC) of the heterocompounds, which indicates the effectiveness of these compounds against fungus growth at a particular concentration. These synthetic heterocyclic compounds find increasing applications in material science, medicinal chemistry, and biochemistry due to their antifungal and antioxidant properties.     

Simulation and optimization of the continuous tower process for styrene polymerization

The continuous tower process, a popular industrial process for the manufacture of polystyrene, was simulated and optimized. A kinetic model for the thermal polymerization of styrene, which takes into account the Trommsdorff effect and the volume change accompanying the reaction, was developed. This was used to formulate model equations for the continuous flow stirred tank reactor (CSTR) and plug flow reactor (several sections) in the tower process. The model can predict monomer conversion, number‐ and weight‐average molecular weights, polydispersity index (PDI), and temperature at various locations in the unit, under specified operating conditions. Multiobjective optimization of this process was also carried out, for which an adaptation of a genetic algorithm (GA) was used. The two objectives were maximization of the final monomer conversion and minimization of the PDI of the product. The conversion in the CSTR was constrained to lie within a desired range, and polymer having a specified value of the number‐average molecular weight was to be produced. The optimal solution was a unique point (no Pareto sets were obtained). The optimal solutions indicated that the tower process is operated under near‐optimal conditions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 775–788, 2004     

An experimental study on on-line optimizing control of free radical bulk polymerization in a rheometer-reactor assembly under conditions of power failure

An experimental study on the on-line optimizing control of a sample free radical bulk polymerization system, namely, methyl methacrylate (MMA), is carried out in a rheometer-reactor assembly. Two initiator loadings and three cases involving external disturbances (power failure) are studied. The disturbances are assumed to be of two kinds: one that leads to a sudden increase in the temperature of the reaction mass (cooling water pump failure) over the planned temperature history, T(t), and one leading to a sudden drop in the temperature (heater failure). The temperature and the viscosity, η, histories are used to describe the ‘state’ (conversion, x_m, and weight-average molecular weight, M_w) of the polymerizing mass. The polymerization is first carried out under an off-line computed optimal temperature history, T_op(t), obtained using the adapted jumping gene version of the elitist genetic algorithm (GA-II-aJG). A planned disturbance is introduced after the start of polymerization and continues for a pre-specified duration. A new optimal temperature history, T_reop(t), is calculated on-line (in about 3 min of real time) using GA-II-aJG. This is implemented as soon as the disturbance is rectified. Experimental values of x_m(t), M_w(t) and η(t) are also measured. These are observed to be in good agreement with model predictions for all the cases. It is found that the information on the viscosity of the reaction mass can be used effectively for on-line optimizing control. This can help ‘save’ the batch (give a product having the desired values of the average molecular weights) optimally, in as short a reaction time as possible. The effect of re-tuning of the model parameters using experimental data on the temperature, T_exp(t), and the viscosity, η(t), is also demonstrated.     

Long-Term Exposure to Nanosized TiO2 Triggers Stress Responses and Cell Death Pathways in Pulmonary Epithelial Cells

There is little in vitro data available on long-term effects of TiO₂ exposure. Such data are important for improving the understanding of underlying mechanisms of adverse health effects of TiO₂. Here, we exposed pulmonary epithelial cells to two doses (0.96 and 1.92 µg/cm²) of TiO₂ for 13 weeks and effects on cell cycle and cell death mechanisms, i.e., apoptosis and autophagy were determined after 4, 8 and 13 weeks of exposure. Changes in telomere length, cellular protein levels and lipid classes were also analyzed at 13 weeks of exposure. We observed that the TiO₂ exposure increased the fraction of cells in G1-phase and reduced the fraction of cells in G2-phase, which was accompanied by an increase in the fraction of late apoptotic/necrotic cells. This corresponded with an induced expression of key apoptotic proteins i.e., BAD and BAX, and an accumulation of several lipid classes involved in cellular stress and apoptosis. These findings were further supported by quantitative proteome profiling data showing an increase in proteins involved in cell stress and genomic maintenance pathways following TiO₂ exposure. Altogether, we suggest that cell stress response and cell death pathways may be important molecular events in long-term health effects of TiO₂.     

Enantioselective Hydrolytic Kinetic Resolution of 1,2-epoxy-3-phenoxy Propane Derivatives by New Chiral (Salen) Cobalt Complexes

In the present letter, for the first time, the efficacy of hydrotalcite-like layered double hydroxides (LDHs) materials as alternative and novel catalyst precursors for the synthesis of carbon nanotubes (CNTs) via catalytic chemical vapor deposition (CCVD) of acetylene was reported. Nanometer-sized cobalt particles were prepared by calcination of a single molecular LDH precursor containing cobalt (II) and aluminum (III) and following by a process of reduction. Multi-walled CNTs with uniform diameters were obtained using the as-synthesized catalyst in the reaction.     

New route for preparation of luminescent mercaptoethanoate capped cadmium selenide quantum dots

We report a synthesis of cadmium selenide quantum dots (Q-CdSe) by refluxing a mixture of cadmium acetate, selenium powder, sodium sulfite and 2-mercaptoethanol in N,N′-dimethyl formamide (DMF)/water solution. X-ray and electron diffractions suggest the formation of hexagonal phase of size quantized CdSe. Based on TEM analysis, the formation of nanoparticles with an average diameter of 3.5 ± 0.5 nm is inferred. Their sols in DMF and dimethyl sulphoxide (DMSO) gave characteristic absorption peaks at 300 nm and 327 nm, which is attributed to the formation of high quality, size quantized CdSe particles. Extracted particles from the sol were readily redispersed in DMF and DMSO, which were diluted further with water without losing their optical and colloidal properties. FTIR spectroscopy suggested the formation of 2-mercaptoethanol thiolate on the particle surface, with free-OH groups available for linkage. Sols in DMSO and their solutions in water displayed an intense photoluminescence (PL).     

Synthesis and characterization of amine‐functionalized amphiphilic block copolymers based on poly(ethylene glycol) and poly(caprolactone)

A series of amine‐functionalized block copolymers, poly(caprolactone)‐block‐poly(ethylene glycol) (PCL‐b‐PEG), were synthesized by ring‐opening bulk polymerization (ROP) of ε‐caprolactone (ε‐CL) initiated through the hydroxyl end of the amino poly(ethylene glycol) (PEG) used as a macroinitiator in the presence of stannous 2‐ethylhexonoate [Sn(Oct)₂]. The polymerization and end functionality of the polymer were studied by different physicochemical techniques (¹H NMR, Fourier transform infrared and X‐ray photoelectron spectroscopy, gel permeation chromatography and thermogravimetric analysis). Thermal, crystalline and mechanical properties of the polymer were thoroughly analyzed using differential scanning calorimetry, wide‐angle X‐ray diffractometry and tensile testing, respectively. The results showed a linear improvement in crystallinity and mechanical properties of the polymer with the content of PEG. Thus the synthesized functional polymers can be used as excellent biomaterials for the delivery of polyanions, as well as macroinitiators for the synthesis of A–B–C‐type block copolymers. Copyright © 2006 Society of Chemical Industry     

AC conductivity in rare earth ions doped vanadophosphate glasses

Room temperature density and AC conductivity in the temperature range 300–525 K and frequency range 50 Hz to 5 MHz have been investigated in a set of La₂O doped vanadophosphate glasses. The density decreased and total conductivity increased with increase of La₂O content. The high temperature electrical conductivity has been analyzed using Mott’s small polaron model and polaron activation energies were determined. The polaron activation energy decreased marginally with increase of lanthanum content, at all frequencies of interest. These results have been attributed to the presence of mixed ion–polaron conduction in the present glasses. It is for the first time that La₂O doped vanadophosphate glasses have been investigated for AC conductivity and despite heaviness of lanthanum ions, the mixed ion–polaron conduction has been detected. Frequency dependence of AC conductivity has been considered under the correlated barrier hopping (CBH) model of single electron hopping.