Tuning of shear thickening behavior and elastic strength of polyvinylidene fluoride via doping of ZnO-graphene

ZnO rice like nonarchitects are grafted on the graphene carbon core via a rapid microwave synthesis route. The prepared grafted systems are characterized via XRD, SEM, RAMAN, and XPS to examined the structural and morphological parameters. Zinc oxide grafted graphene sheets (ZnO-G) are further doped in β-phase of polyvinylidene fluoride (PVDF) to prepare the polymer nanocomposites (PNCs) via mixed solvent approach (THF/DMF). β-phase confirmation of PVDF PNCs is done by FTIR studies. It is observed that ZnO-G filler enhances the β-phase content in the PNCs. Non-doped PVDF and PNCs are further studied for rheological behavior under the shear rate of 1–100 s⁻¹. Doping of ZnO-G dopant to the PVDF matrix changes its discontinuous shear thickening (DST) behavior to continues shear thickening behavior (CST). Hydrocluster formation and their interaction with the dopant could be the reason for this striking DST to CST behavioral change. Strain amplitude sweep (10⁻³% -10%) oscillatory test reveals that the PNCs shows extended linear viscoelastic region with high elastic modulus and lower viscous modulus. Effective shear thickening behavior and strong elastic strength of these PNCs present their candidature for various fields including mechanical and soft body armor applications.     

Development of docetaxel nanocapsules for improving in vitro cytotoxicity and cellular uptake in MCF-7 cells

The aim of this study was to fabricate docetaxel loaded nanocapsules (DTX-NCs) with a high payload using Layer-by-Layer (LbL) technique by successive coating with alternate layers of oppositely charged polyelectrolytes. Developed nanocapsules (NCs) were characterized in terms of morphology, particle size distribution, zeta potential (ζ-potential), entrapment efficiency and in vitro release. The morphological characteristics of the NCs were assessed using transmission electron microscopy (TEM) that revealed coating of polyelectrolytes around the surface of particles. The developed NCs successfully attained a submicron particle size while the ζ-potential of optimized NCs alternated between (+) 34.64?±?1.5 mV to (?) 33.25?±?2.1 mV with each coating step. The non-hemolytic potential of the NCs indicated the suitability of the developed formulation for intravenous administration. A comparative study indicated that the cytotoxicity of positively charged NCs (F4) was significant higher (p?in vitro on MCF-7 cells. Furthermore, cell uptake studies evidenced a higher uptake of positive NCs (≥1.2 fold) in comparison to negative NCs. In conclusion, formulated NCs are an ideal vehicle for passive targeting of drugs to tumor cells that may result in improved efficacy and reduced toxicity of encapsulated drug moiety.     

Detailed study on fusion characteristics of rigid poly(vinyl chloride) nanocomposites: The comparison of using multiple regression analysis and artificial neural network

Fusion behavior of poly(vinyl chloride) (PVC) compounds plays an important role in the development of physical properties of processed material. The fusion characteristics in PVC processing are governed by material variables that affect the fusion with some interactions. In this research, the aim was to characterize the effects of formulation ingredients on fusion characteristics of PVC. Four material parameters, including the contents of nanoclay (NC), azodicarbonamide, calcium stearate, and processing aid, are proposed as affecting variables. The fusion time (FT) as well as fusion factor (FF) are considered fusion indicators and are experimentally determined in some different levels of affecting parameters. The multivariable regression analysis (MRA) and the Artificial Neural Network (ANN) modeling are considered as two analytical methods. The regression analysis result for the FT denotes, in part, significant linear and quadratic effects of NC and also its significant interactions with azodicarbonamide and calcium stearate, whereas that of FF indicates only a linear effect of NC. ANN modeling is performed with a three‐layer (input, hidden, and output) neural network. The results of the comparison of the MRA and ANN predictions with experimental values are reported as the correlation coefficient (R²), mean‐square error, and mean absolute percentage error for both FF and FT parameters. The obtained values clearly denote that the ANN results are more precise and especially more general than those of MRA. However, in the case of FT, improvement of the ANN modeling is much greater than that of FF. J. VINYL ADDIT. TECHNOL., 21:147–155, 2015. © 2014 Society of Plastics Engineers     

Recent Developments in Integrated Solar Combined Cycle Power Plants

Global concern for depleting fossil fuel reserves have been compelling for evolving power generation options using renewable energy sources. The solar energy happens to be a potential source for running the power plants among renewable energy sources. Integrated Solar Combined Cycle(ISCC) power plants have gained popularity among the thermal power plants. Traditional ISCC power plants use Direct Steam Generation(DSG) approach. However, with the DSG method, the ISCC plant’s overall thermal efficiency does not increase significantly due to variations in the availability of solar energy. Thermal Energy Storage(TES) systems when integrated into the solar cycle can address such issues related to energy efficiency, process flexibility, reducing intermittency during non-solar hours. This review work focuses and discusses the developments in various components of the ISCC system including its major cycles and related parameters. The main focus is on CSP technologies, Heat Transfer Fluid(HTF), and Phase Change Material(PCM) used for thermal energy storage. Further, study includes heat enhancement methods with HTF and latent heat storage system. This study will be beneficial to the power plant professionals intending to modify the solar-based Combined Cycle Power Plant(CCPP) and to retrofit the existing Natural Gas Combined Cycle(NGCC) plant with the advanced solar cycle.     

Improved low energy adaptive clustering hierarchy and its optimum cluster head selection

ABSTRACT

Wireless sensor networks (WSNs) play a vital role in present-day world, which are being used in different types of applications and occupy an important part in networking domain. The main objective of WSNs is to sense and collect the information from a given area of interest and provide the gathered data to the sink. WSN comprises of number of sensor nodes with batteries of limited energy for communication and computational activities, which are not possible to recharge the batteries after their deployment in the region of interest. Therefore, saving battery energy and utilising the limited power to the optimum level for extending network lifetime became the main factor of WSN. Hence, optimum cluster head (CH) selection will make the network to support longer lifetime and balanced energy consumption during its lifetime. Our proposed protocol selects the optimum CH and found out to be more efficient than the existing low energy adaptive clustering hierarchy. The simulated output shows better network lifetime and in some other performance metric.     

A multi-tier based clustering framework for scalable and energy efficient WSN-assisted IoT network

Wireless Networks - The effectiveness of wireless sensor network (WSN) in Internet of Thing (IoT) based large scale application depends on the deployment method along with the routing protocol. The...     

Thin film composite sodium alginate membranes for dehydration of acetic acid and isobutanol

Dehydration of widely used organic solvents such as acetic acid (AA) and isobutanol (IB) is challenging tasks, which form close boiling mixtures with water. Sodium alginate (SA) thin film composite membranes were prepared and crosslinked with 2,4‐toluene diisocyanate (TDI) and glutaraldehyde for dehydration of IB and AA/water mixtures through pervaporation (PV). The crosslinked and uncrosslinked SA composite membranes were characterized by Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction, thermogravimetric analysis, scanning electron microscopy, and universal testing machine for intermolecular interactions, crystalline nature, thermal stability, surface morphology, and tensile strength, respectively. At a feed composition of 98 wt % IB and 95 wt % AA aqueous solutions, the TDI crosslinked SA composite membrane exhibited separation factors of 3229 and 708 with reasonable fluxes of 0.021 and 0.012 kg m^?2 h^?1, respectively. The results obtained in the study for IB and AA systems were compared with other SA membranes reported in the literature. The membranes appeared to have potential for commercial PV ability to dehydrate the solvents up to desirable purity levels (>99%) and feasibility of preparing them in a composite form which would enable scale‐up into modular configurations. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 40018.     

Mathematical modelling of solar radiation incident on tilted surface for photovoltaic application at Bhopal,M.P., India

In general, solar radiations are the combination of beam plus diffuse and ground-reflected radiation. The availability of recorded data on a tilted surface is very rare due to lack of measuring equipment and techniques involved. In this study, a standard procedure is adopted for estimation of solar radiation on a tilted surface for a location in Central region of India. Solar radiation is estimated for three tilted positions: First, solar collector tilt equal to latitude angle, second, solar collector tilt equal to latitude angle +15° and third, solar collector tilt at latitude ?15°. Total global solar radiation estimated on the inclined surface for various photovoltaic (PV) modules was used to obtain the annual energy yield based on the estimated value. It was found that on an average, 14?kWh/m² of annual energy output can be obtained for monocrystalline solar PV module corresponding to the inclination of 23.26° latitude at Bhopal.     

Thermal modeling for greenhouse heating by using thermal curtain and an earth–air heat exchanger

In this paper, a thermal model for heating of greenhouse by using different combinations of inner thermal curtain, an earth–air heat exchanger, and geothermal heating has been developed. The analysis incorporates the study of thermal performance of three-zone greenhouse. The calculations have been made for a typical production greenhouse in southern part of Argentina; available climatic data has been used. The thermal performance of a greenhouse having thermal curtain and an earth–air heat exchanger has been compared with a greenhouse having thermal curtain and geothermal energy. It is seen that the fluctuations in temperature in the vicinity of plants are comparable in the two cases. From the results, it is seen that an earth–air heat exchanger might prove an alternative source for heating of greenhouse when geothermal energy is not available. It has also been observed that, the increase in temperature of zone I is more for the greenhouse with geothermal than the greenhouse with an earth–air heat exchanger.