Dielectric relaxation in complex perovskite Ba(Bi1/2Ta1/2)O3

A new lead-free perovskite Ba(Bi_1/2Ta_1/2)O₃ was prepared by conventional ceramic fabrication technique at 1,200 °C/4 h in air atmosphere. The crystal symmetry, space group and unit cell dimensions were determined from the experimental results using FullProf software. The crystallite size and lattice strain were estimated from Williamson-Hall approach. XRD analysis of the compound indicated the formation of a single-phase cubic structure with the space group Pm3m. EDAX and SEM studies were carried out in order to evaluate the quality and purity of the compound. Permittivity data showed a low temperature coefficient of capacitance (T _CC  < 4%) up to +125 °C. Complex impedance analyses suggested the dielectric relaxation to be of non-Debye type. Electric modulus studies supported the hopping type of conduction in Ba(Bi_1/2Ta_1/2)O₃.     

SIRA: Scale illumination rotation affine invariant mask R-CNN for pedestrian detection

Applied Intelligence - In this paper, we resolve the challenging obstacle of detecting pedestrians with the ubiquity of irregularities in scale, rotation, and the illumination of the natural scene...     

Multi-stage deep probabilistic prediction for travel demand

Applied Intelligence - Accurate demand prediction is an essential component of any decision support system for smart vehicle dispatching. However, predicting real time demand at the...     

Properties of PET/clay nanocomposite films

Polyethylene terephthalate (PET) nanocomposite films were prepared by cast extrusion followed by uniaxial stretching, using chill rolls. Transmission electron microscopy (TEM) and wide angle X‐ray diffraction (WAXD) showed that the clay layers were aligned in the machine direction (MD) in the PET/clay nanocomposite (PCN) films. Differential scanning calorimetry (DSC) showed that PCN films have higher crystallinity than the neat PET films, possibly due to the nucleating role of the silicate layers. The PCN films became hazier as the clay content increased, but the film transparency remained in the acceptable range. Oxygen permeability of the PCN films decreased by 23% compared to the neat PET film. This is comparable with predictions of models proposed in the literature. Silicate incorporation brought about 20% increase in the tensile modulus, while the puncture and tear propagation resistance were reduced, due to brittleness of the PCN films. The measured modulus (1.7 GPa) was somewhat smaller than the values predicted using the Pseudoinclusion model (2.1 GPa). POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers     

Light transmission and haze of polyethylene blown thin films

The surface and bulk morphologies of polyethylene blown films are obtained using non‐contact Atomic Force Microscopy (AFM). Based on these experimental observations, a model using the Mie Scattering theory is proposed to describe the forward transmission and scattering of a plane wave through the film. The light transmission properties are computed from the proposed model and the results are validated by experimental measurements.     

Investigation on the effect of spinning conditions on the properties of hollow fiber membrane for hemodialysis application

Polyethersulfone (PES) hollow fiber membranes were fabricated via the dry‐wet phase inversion spinning technique, aiming to produce an asymmetric, micro porous ultrafiltration hollow‐fiber specifically for hemodialysis membrane. The objective of this study is to investigate the effect of spinning conditions on the morphological and permeation properties of the fabricated membrane. Among the parameters that were studied in this work are air gap distance, dope extrusion rate, bore fluid flow rate, and the take‐up speed. The contact angle was measured to determine the hydrophilicity of the fibers. Membrane with sufficient hydrophilicity properties is desired for hemodialysis application to avoid fouling and increase its biocompatibility. The influences of the hollow fiber's morphology (i.e., diameter and wall thickness) on the performance of the membranes were evaluated by pure water flux and BSA rejection. The experimental results showed that the dope extrusion rate to bore fluid flow rate ratio should be maintained at 1:1 ratio to produce a perfectly rounded asymmetric hollow fiber membrane. Moreover, the flux of the hollow fiber spun at higher air gap distance had better flux than the one spun at lower air gap distance. Furthermore, spinning asymmetric hollow fiber membranes at high air gap distance helps to produce a thin and porous skin layer, leading to a better flux but a relatively low percentage of rejection for BSA separation. Findings from this study would serve as primary data which will be a useful guide for fabricating a high performance hemodialysis hollow fiber membrane. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43633.     

Synthesis,Characterization and Surface Properties of Amidosulfobetaine Surfactants Bearing Odd-Number Hydrophobic Tail

Three amidosulfobetaine surfactants were synthesized namely: 3-(N-pentadecanamidopropyl-N,N-dimethyl ammonium) propanesulfonate (2a); 3-(N-heptadecanamidopropyl-N,N-dimethyl ammonium) propanesulfonate (2b), and 3-(N-nonadecanamidopropyl-N,N-dimethyl ammonium) propanesulfonate (2c). These surfactants were prepared by direct amidation of commercially available fatty acids with 3-(dimethylamino)-1-propylamine and subsequent reaction with 1,3-propanesultone to obtain quaternary ammonium salts. The synthesized surfactants were characterized by IR, NMR and mass spectrometry. Thermogravimetric analysis (TGA) results showed that the synthesized surfactants have excellent thermal stability with no major thermal degradation below 300 °C. The critical micelle concentration (CMC) values of the surfactants 2a and 2b were found to be 2.2 × 10^?4 and 1.04 × 10^?4 mol/L, and the corresponding surface tension (γ_CMC) values were 33.14 and 34.89 mN m^?1, respectively. The surfactants exhibit excellent surface properties, which are comparable with conventional surfactants. The intrinsic viscosity of surfactant (2b) was studied at various temperatures and concentrations of multi-component brine solution. The plot of natural logarithm of relative viscosity versus surfactant concentration obtained from Higiro et al. model best fit the surfactant behavior. Due to good salt resistance, excellent surface properties and thermal stability, the synthesized surfactant has potential to be used in various oil field applications such as enhanced oil recovery, fracturing, acid diversion, and well stimulation.