Graphene Based Nanocomposite Electrodes for Energy Storage in Supercapacitors

There is an unmet need to develop high performance energy storage systems (ESS), capable of storing energy from both renewable and non-renewable sources to meet the current energy crisis and depletion of non-renewable sources. Amongst many available ESS, supercapacitors (ECs) are the most promising because they exhibit a high charge/discharge rate and power density, along with a long cycle life. A novel use of atomically thin carbon allotropes like graphene, carbon nanotubes (CNTs) and electrically conducting polymers (ECPs) such as polypyrrole (PPy) have been studied as high performance conducting electrodes in supercapacitor application. A novel templated sustainable nanocomposite electrode has been fabricated using cellulose extracted from Cladophora c. aegagropila algae as a component of the assembled supercapacitor device which later has been transitioned to a unique template-less freestanding nanocomposite supercapacitor electrode[1]. The specific capacitance of polypyrrole-graphene-cellulose nanocomposite as calculated from the cyclic voltammetry curve is 91.5 F g-1 at the scan rate 50 m Vs-1 in the presence of 1M NaCl electrolyte. The open circuit voltage of the device with polypyrrole -graphene-cellulose electrode was found to be around 225 m V and that of the polypyrrole -cellulose device is only 53 m V without the presence of graphene in the nanocomposite electrode. Understanding the fundamentals by fabricating template nanocomposite electrode led to developing a unique nanocomposite template-less freestanding film which comprises of polypyrrole-graphene-CNT hybrid[2]. Various experiments have been performed using different electrolytes such ascorbic acid, sodium sulfate and sulfuric acid in different scan rates. The specific capacitance of polypyrrole-graphene-CNT nanocomposite with 0.1 wt% of graphene-CNT, as calculated from cyclic voltammetry curve is 450 F g-1 at the scan rate 5 m V s-1. For the first time a nanofibrous membrane has been developed as a separator which acts as an electrolyte reservoir and ionic diffusion membrane. The performance of the fabricated supercapacitor device has been analyzed using a multimeter and compared with a conventional alkaline (1.5 V) battery. Lighting up of 2.2 V light emitting diode has been demonstrated using the fabricated supercapacitor

Fabrication and Experimental Analysis of Axially Oriented Nanofibers

A novel design of a laboratory built axially rotating collector (ARC) having capability to align electrospun nanofibers have been described. A detailed morphological comparison of such nanofibers orientation and their geometry is done using scanning electron microscopy (SEM). For comparison various polymeric solutions were electrospun on conventional static collector as well as ARC. The average diameter of polyvinyl alcohol (PVA) nanofibers was found to be 250 nm while polycaprolactone (PCL) nanofibers were found to be within a range of 600–800 nm. Conducting nanoparticles such as graphene and multi-walled carbon nanotubes (MWNTs) mixed with polymer solutions shown to have a significant influence on the overall geometry of these nanofibers and their diameter distribution. It is evident from the SEM analysis that both graphene and MWNTs in polymer solution play a crucial role in achieving a uniform diameter of nanofibers. Lastly, the formation of the aligned nanofibers using ARC has been mathematically modeled and the electromagnetic field governing the process has been simulated

Effect of Long-Term Application of Inorganic Fertilizers, Organic Manure, and Lime on Different Forms of Potassium in Soil under Maize-Wheat Cropping System

The field study was undertaken with the major emphasis on potassium fractionation and its contribution in acid alfisol soils as affected by adoption of continuous cropping, fertilization, and manuring under maize-wheat cropping system in same field over 62 years of crop cycles. The experiment consisted of fourteen treatments, replicated thrice times in a randomized block design, out of which nine treatments were selected for the present study. The selected treatments were as follows - control, T2-100% N, T3- FYM, T4-100% NP, T5-100% NPK, T6- 1/2(N+FYM) + P(A-X/2) + K(B-Y/2) (INM), T7-100% NPK + Lime where the lime application in LR once in 4 years, T8-Lime+ FYM+ P(A-X) + K(B-Y), T9-Lime+N. Surface soil (0-15cm) and subsurface soil (16-30 cm) samples were collected after the harvest of wheat in 2017-18 to observe the initial Physico-chemical properties. Different fractions of potassium, viz., water-soluble K, exchangeable K, available K, 1NHNO3K, non-exchangeable K, Lattice K, and Total K were analyzed for the study. There was a significant difference among the different treatments with respect to potassium fractions in 0-15 cm, and 16-30 cm layers. Moreover, K fractions were significantly decreased with increasing depth of soil. Results showed that the percentage contribution of different forms of K with regard to the total K in surface soil and subsurface soil followed as: Lattice K (68.75-78.11%) > Non – Exchangeable K (19.15-25.49%) > Exchangeable K (1.65-2.45%) >Water soluble K (0.18-0.62%). Application of N and P without K caused depletion of soil, water-soluble K, available K, exchangeable K, non-exchangeable K, and lattice K because of continuous omission of potassium content during the all crop growing stages or the simultaneous leaching nature of residual potassium under same field of the experiment. Therefore, the present investigation stresses the vital importance of the inclusion of organic manure and lime in the fertilizer schedule to maintain soil K dynamics over the long run under the maize-wheat cropping system

Effect of public-private partnership in treatment of sexually transmitted infections among female sex workers in Andhra Pradesh, India

Background & Objectives: Providing sexually transmitted infection (STI) services to female sex workers (FSWs) in rural and resource constrained settings is a challenge. This paper describes an approach to address this challenge through a partnership with government health facilities, and examines the effect of this partnership on the utilization of STI services by FSWs in Andhra Pradesh, India. Methods: Partnerships were formed with 46 government clinics located in rural areas for providing STI treatment to FSWs in 2007. Government health facilities were supported by local and State level non-government organizations (NGOs) through provision of medicines, training of medical staff, outreach in the communities, and other coordination activities. Data from programme monitoring and behaviour tracking survey were used to examine the accessibility and acceptability in utilization of STI services from partnership clinics. Results: The number of FSWs accessing services at the partnership clinics increased from 1627 in 2007 to over 15,000 in 2010. The average number of annual visits by FSWs to these clinics in 2010 was 3.4. In opinion surveys, the majority of FSWs accessing services at the partnership clinics expressed confidence that they would continue to receive effective services from the government facilities even if the programme terminates. The overall attitude of FSWs to visit government clinics was more positive among FSWs from partnership clinic areas compared to those from non-partnership clinic areas. Interpretation & Conclusions: The partnership mechanism between the NGO-supported HIV prevention programme and government clinic facilities appeared to be a promising opportunity to provide timely and accessible STI services for FSWs living in rural and remote areas

Protective Ceramic Coatings for Solid Oxide Fuel Cell (SOFC) Balance-of-Plant Components

Solid oxide fuel cells (SOFCs) have the potential to meet the growing need for electrical power generation if the cost per megawatt can be further reduced. Currently, SOFC stacks are replaced too frequently to be cost competitive. SOFC service life can be extended by preventing chromium- (Cr-) bearing species from evaporating from the interior surfaces of balance of plant (BOP) components and poisoning the cathode to increase the lifetime. We have developed yttria-stabilized zirconia (YSZ) and aluminum oxide- (Al2O3-) modified sol-gel paints or inks for coating BOP components. 430 stainless steel (430SS) substrates with three surface conditions were coated with the 0.8–1.5 µm thick YSZ and Al2O3 paints. The coated 430SS samples were tested for thermal cycling resistance, thermal soak, and Cr evaporation. Thermal soak and thermal cycling test results show promise for the YSZ-coated 430SS substrates. The Cr evaporation test of a coated substrate showed a 51% reduction in Cr generation, when compared with a bare substrate