Stress‐relaxation behavior of natural rubber/polystyrene and natural rubber/polystyrene/natural rubber‐graft‐polystyrene blends

We studied the stress‐relaxation behavior of natural rubber (NR)/polystyrene (PS) blends in tension. The effects of strain level, composition, compatibilizer loading, and aging on the stress‐relaxation behavior were investigated in detail. The dispersed/matrix phase morphology always showed a two‐stage mechanism. On the other hand, the cocontinuos morphology showed a single‐stage mechanism. The addition of a compatibilizer (NR‐g‐PS) into 50/50 blends changed the blend morphology to a matrix/dispersed phase structure. As a result, a two‐step relaxation mechanism was found in the compatibilized blends. A three‐stage mechanism was observed at very high loadings of the compatibilizer (above the critical micelle concentration), where the compatibilizer formed micelles in the continuous phase. The aged samples showed a two‐stage relaxation mechanism. The rate of relaxation increased with strain levels. The aging produced interesting effects on the relaxation pattern. The rate of relaxation increased with temperature due to the degradation of the samples. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Molybdenum/graphene – Based catalyst for hydrogen evolution reaction synthesized by a rapid photothermal method

Catalysis of the hydrogen evolution reaction (HER) is important in the development of an energy economy based on clean hydrogen gas. In this work, we report a new catalyst material for the generation of hydrogen via hydronium reduction. The new material, which consists of MoO₂, sulfur, and graphene, was prepared by co-reduction of molybdenum salt and graphite oxide in air in the presence of focused solar radiation. The potential utility of this material for HER catalysis was evaluated by cyclic and linear-sweep voltammograms and compared against a Pt/C commercial catalyst. The MoO₂/graphene hybrid nanocomposite exhibits a Tafel slope of 47 mV/dec and hydrogen evolution at a potential only ∼120 mV more negative than the standard Pt/Carbon catalyst at 10 mA/cm² current density. The hydrogen gas generated by the catalytic material was measured using gas chromatography. The simple synthesis and low overpotential suggests that this hybrid composite has potential as an HER catalyst.     

D-optimal designs for sorption kinetic experiments: Slabs

In this paper, we report the results of a numerical study of how the model parameters for the kinetics of sorption based on Fick’s law of diffusion coupled with an external convective mass transfer coefficient affect the D-optimal support points. The geometry studied was that of a slab of finite thickness but infinite width and length so that diffusion was characterized by a single dimension. Although a wide range of diffusivities characteristic of many foodstuffs were used, it was shown that the two support points for the design could be expressed in terms of just the dimensionless Biot number and the dimensionless Fourier modulus.     

D-optimal designs for the Cross viscosity model applied to guar gum mixtures

D-optimal designs are developed using the Cross viscosity model for aqueous solutions of guar gum. Designs are developed for a 2⁶ factorial design in the model parameters to study the effect of the model parameters on the experimental design. Analysis of this study shows that of the six experimental design points, two were independent of the six model parameters and the remaining four were dependent on only three of the model parameters. Additional analysis using ANOVA showed that only two of the model parameters, concentration and shear-rate exponents, statistically affect the design efficiency at the 0.05 level within the range of the model parameters studied. Furthermore, it is shown that incorrectly specifying the model parameters by as much as 50% reduces the design efficiency to 50–90%.     

TiO2-UV photocatalytic oxidation of Reactive Yellow 14: effect of operational parameters

The photocatalytic decolourisation and degradation of an azo dye Reactive Yellow (RY14) in aqueous solution with TiO(2) as photocatalyst in slurry form has been carried out using UV-A radiation (365 nm). The effect of various parameters such as catalyst loading, radiation intensity and initial dye concentration on the dye removal was investigated to find optimum conditions. The decolourisation and degradation kinetics have been analysed. Both follow modified Langmuir-Hinshelwood kinetic (L-H) model. A study on the effect of electron acceptors on photooxidation reveals that both decolourisation and degradation increase in the presence of H(2)O(2), (NH(4))(2)S(2)O(8), KBrO(3), to certain dosage beyond which the enhancement effect is negligible. But negative effects are observed in the presence of NaCl or Na(2)CO(3).     

Solar assisted photocatalytic and photochemical degradation of Reactive Black 5

The photocatalytic oxidative degradation of Reactive Black 5 (RB 5) has been investigated using TiO(2)-P25 as photocatalyst and sunlight as irradiation source in slurry form. The degradation was carried out at different experimental conditions to optimize the parameters such as amount of catalyst, concentration of dye and pH. A complete degradation of 3.85 x 10(-4) M dye solution under solar irradiation was observed in 3.5 h. The photochemical degradation using hydrogen peroxide results in the partial removal of the dye.     

An Easily Accessible NIR-Absorbing Tetraimide Dye and its Biotherapeutics Based Photothermal and Photodynamic Therapy

Organic π-systems with strong absorption in the near-infrared (NIR) region are promising candidates for photothermal therapy (PTT) and photodynamic therapy (PDT). However, the synthesis of NIR π-systems involves several steps and many of them display poor photothermal conversion efficiency (PTCE). Here we present the synthesis of a tetraimide-based donor-acceptor NIR π-system, 2EHex-B having absorbance in the range of 350–900 nm. Importantly, 2EHex-B is synthesized in two steps with a 70 % high yield. Moreover, 2EHex-B shows excellent PTCE up to 50 % and good biocompatibility when encapsulated in liposomes. The liposome coated 2EHex-B , ( L-2EHex-B) showed good thermal stability and efficiently kills cancer cells via PTT. Additionally, L-2EHex-B shows good reactive singlet oxygen generation ability when irradiated with a 750 nm laser. 3D cell culture model - multicellular spheroids test was performed to evaluate the efficiency of PTT. The spheroids treated with L-2EHex-B after NIR light irradiation showed increased cell death from the core of the tumor toward the periphery. The easy access to 2EHex-B makes it a potential candidate for minimally invasive cancer treatment.     

Missing data estimation and IoT-based flyby monitoring of a water distribution system: Conceptual and experimental validation

Achieving uninterrupted water supply to the consumer node is considered to be the significant aspect for urban water distribution system (WDS). Under circumstances such as sensor failures or large sampling interval, the intermittent vital data are ignored, which lead to the missing data problem. In this work, an enhanced version of Kalman filter (KF) is proposed termed to be customized KF (CKF). The proposed CKF is equipped to handle the state- and input-dependent noises, which are amplified based on the input and states in WDS. These noises corrupt the measured response from the WDS added to the conventional sensor and model uncertainties. In this case, a real-world-existing WDS is considered to test the credibility of the proposed algorithm. This reduces the complexity of the computation and the sampling rate of the measured head level, and the flows are considered to be random. The study indicates that the proposed CKF performs better in estimating the missing data voids with the noise-corrupted measurements. To have the continuous monitoring accessible in remote sections, the vital parameters are monitored through Internet of Things (IoT) in android platform. The estimated data from the MATLAB and the sensor data of the consumer demands are monitored through user-defined android application. This technique provides the advantage of monitoring the WDS in flyby condition and also even in the presence of any sensor failures, which also helps to localize the fault location.     

Thermal diffusivity of lead titanate/polyvinylidene fluoride-trifluoroethylene nanocomposites by the mirage method

Thermal diffusivity D of lead titanate/polyvinylidene fluoride-trifluoroethylene {PT/P(VDF-TrFE)} nanocomposites has been measured by the skimming configuration of the mirage method. Diffusivity values are calculated by measuring the phase variation of the probe beam deflection signal upon changing both the vertical and horizontal probe beam offset values at different modulation frequencies of the pump beam. The thermal diffusivity of the nanocomposites is found to depend on the volume fraction of the ceramic in the composites. The composites with higher volume fraction of ceramic have higher thermal diffusivity and conductivity. Different models were used to predict the thermal conductivity (k) of composites and the measured values agree quite well with the Looyenga model.