AHW-BGOA-DNN: a novel deep learning model for epileptic seizure detection

Neural Computing and Applications - “Brain–Computer Interface” (BCI)—a real-life support system provides a way for epileptic patients to improve their quality of life. In...     

Microstructure determination and thermal studies of n‐acryloylcarbazole/vinyl acetate copolymers

Copolymers of N‐acryloylcarbazole (A) and vinyl acetate (V) were synthesized by bulk polymerization using benzoyl peroxide (BPO) as free‐radical initiator at 65°C in different in‐feed ratios. The composition of the copolymer was determined by ¹H‐NMR spectrum. The comonomer reactivity ratios, determined by Kelen–Tudos (KT) and nonlinear error‐in‐variables (EVM) methods, were r_A= 16.75 ± 1.38, r_V = 0.015 ± 0.002, and r_A = 16.36, r_V = 0.015, respectively. Complete spectral assignments of the ¹H and ¹³C{¹H} NMR spectra of the copolymers were done by the help of distortionless enhancement by polarization transfer (DEPT) and two‐dimensional NMR techniques such as heteronuclear single quantum coherence (HSQC) and total correlation spectroscopy (TOCSY). The methine and methylene carbon resonances were found to be compositional as well as configurational sensitive. The signals obtained were broad pertaining to the restricted rotation of bulky carbazole group. The thermal stability and glass‐transition temperatures (T_g) of the copolymers were found to be dependant on polymer composition and characteristic of rotational rigidity of the polymer chain. Variation in the values of T_g with the copolymer composition was found to be in good agreement with theoretical values obtained from Johnston and Barton equations. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2720–2733, 2007     

Pristine and cadmium-doped zinc oxide: chemical synthesis and characterizations

The chemical synthesis of pristine and cadmium-doped ZnO powders using a simple, cost-effective at 65 °C is reported and characterized for their structures, optical and morphological studies using X-ray diffraction, UV–visible–Near Infra-Red (UV–Vis–NIR) spectroscopy, scanning electron microscopy measurement techniques where XRD spectra confirm the formation of ZnO and Cd-doped ZnO with hexagonal crystal structure. The particle size of ZnO is reduced on Cd-doping from 16 to 14 nm. Plane-view surface morphology analysis supported for spherical-type crystallites and UV–Vis–NIR spectra reveal shift in the band edge of ZnO after Cd-doping. Photo-degradation study of Methylene Blue dye shows Pristine ZnO degrades dye faster than Cd-doped ZnO.     

Chemically deposited nickel oxide as counter electrode for dye sensitized solar cell

Nickel oxide (NiO) thin films have been synthesized by simple and inexpensive chemical bath deposition at low temperature. The synthesized thin films were annealed at 623 K and used for further characterization. Structural and morphological properties of the NiO thin film were characterized using X-ray diffraction and scanning electron microscope (SEM), respectively. The structural study shows the simple cubic formation of NiO thin films with average crystallite size of 9 nm. Honeycomb like surface morphology with porous structure was observed from the SEM study. NiO thin film electrode has been used as a counter electrode in dye sensitized solar cell. Finally, photovoltaic parameters such as short circuit current density (J_sc), open circuit voltage (V_oc), Fill Factor (FF) and efficiency (η) have been studied.     

Isocyanurate based fluorinated polyurethane dispersion for anti-graffiti coatings

Fluorinated polyurethane dispersions (FPUDs) were synthesized using HDI isocyanurate, polyester polyol and DMPA with varying concentrations of trifluoro ethanol (TFE) in the range of 0–9 wt%. Further FPUDs were characterized by FT-IR and ¹H NMR for structural elucidation. Effects of trifluoro ethanol on the dispersion were evaluated by particle size analyzer. It was observed that with increase in TFE, particle size increases. Topography and contact angle were studied by atomic force microscopy (AFM) and goniometer, respectively. To gain more insight into the formation of roughness, power spectral density (PSD) analysis was carried out. It was found that with increase in TFE content, surface roughness increases due to migration of fluorinating agent on the coating substrate and consequently water repellency increases. Nano indentation of coating revealed that fluorinated coating possesses less stiffness and elastic modulus, due to the presence of fluorine on the coating. Further, coatings were analyzed for thermal properties by thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC) which shows the enhancement in thermal stability and glass transition temperature with increase in TFE content. Anti-graffiti test was carried out which showed improved resistance with increasing fluorine content.     

Synthesis and characterization of nanostructured CaSiO3 biomaterial

Here we report a successful preparation of nanostructured calcium silicate by wet chemical approach. The synthesized sample was characterized by various physico-chemical methods. Thermal stability was investigated using thermo-gravimetric and differential thermal analysis (TG-DTA). Structural characterization of the sample was carried out by the X-ray diffraction technique (XRD) which confirmed its single phase hexagonal structure. Transmission electron microscopy (TEM) was used to study the nanostructure of the ceramics while homogeneous grain distribution was revealed by scanning electron microscopy studies (SEM). The elemental analysis data obtained from energy dispersive X-ray spectroscopy (EDAX) were in close agreement with the starting composition used for the synthesis. Superhydrophilic nature of CaSiO₃ was investigated at room temperature by sessile drop technique. Effect of porous nanosized CaSiO₃ on early adhesion and proliferation of human bone marrow mesenchymal stem cells (BMMSCs) and cord blood mesenchymal stem (CBMSCs) cells was measured in vitro. MTT cytotoxicity test and cell adhesion test showed that the material had good biocompatibility and promoted cell viability and cell proliferation. It has been stated that the cell viability and proliferation are significantly affected by time and concentration of CaSiO₃. These findings indicate that the CaSiO₃ ceramics has good biocompatibility and that it is promising as a biomaterial.     

Preparation and characterization of carbon-encapsulated iron nanoparticles and their catalytic activity in the hydrogenation of levulinic acid

This study describes the synthesis of carbon-encapsulated iron nanoparticles using an ultrasonic method and also investigates their catalytic activity. These nanoparticles have been prepared using ultrasonic irradiation followed by annealing at various temperatures. As the annealing temperature of as-prepared α-Fe₂O₃ nanoparticles increased, the sample transformed into γ-Fe₂O₃, Fe₃O₄, and Fe nanoparticles via the reduction process without requiring any additional reducing agents such as H₂ gas, thus, creating a carbon shell surrounding the nanoparticles. By controlling the experimental conditions, Fe nanoparticles of various sizes can be formed with diameters in the range 100–800 nm; these nanoparticles are tightly encapsulated by 20-nm-thick carbon shells. Because of their high saturation magnetization 212 emu g^?1, the carbon-encapsulated Fe nanoparticles can be used for magnetic resonance imaging with a dramatically enhanced efficiency compared to commercially available T ₂ contrast agents. Moreover, the carbon-encapsulated Fe nanoparticles showed its superior catalytic activity and reusability for the hydrogenation of biomass-derived levulinic acid to GVL (99.6 %) in liquid phase.     

Influence of the coupling agent and graphene oxide on the thermal and mechanical behavior of tea dust–polypropylene composites

In this study, the effects of a coupling agent and additive on the physicomechanical (morphological, mechanical, thermal, and swelling) properties of tea dust (TD)–polypropylene (PP) composites were studied. TD–PP composites were prepared with untreated tea dust (UTD) and tetraethylsilane (TES)‐treated TD or silanated tea dust (STD) particles at ratios of 0:100, 10:90, 20:80, 30:70, and 40:60 w/w. Initially, TD particles were grafted by TES as a coupling agent, and these STD particles were then modified with graphene oxide (GO) as an additive to study their effects on the STD–PP composites; these were compared to the STD–PP and UTD–PP composites in accordance with a study of improvements in the mechanical properties. All of the TD–PP composites were analyzed with Fourier transform infrared spectroscopy, scanning electron microscopy, and mechanical, thermal, and physical tests. The thermal and mechanical properties of both the STD–PP and GO‐modified STD–PP composites were found to be improved as compared to those of the UTD–PP composites. So, the recycling of a large amount of TD as a waste material could be useful in the preparation of TD–PP composites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42927.