Effect of Paste Viscosity on Direct-Current Resistance in Improving the Efficiency of Dye-Sensitized Solar Cell

The quality of photoelectrode film plays an important role in producing high performing dye-sensitized solar cell (DSC). A well-deposited film would ensure the stability of photoelectrode material and improve electron transport and recombination. This study aims to evaluate the effect of paste viscosity on the direct-current resistance of the fabricated DSC. Photoelectrode paste of different viscosity was prepared by varying the amount of terpineol as the solvent. Photoelectrode films were then deposited on fluorine-doped tin oxide glass substrate by screen printing method. Electrochemical impedance spectroscopy analysis was utilized to analyse the direct-current resistance of fabricated DSC integrated with different paste viscosity. Direct-current resistance is found to be reduced with increasing paste viscosity. This is attributed to the increase in electron density which reduces the transport as well as recombination resistance leading to an improvement in the conversion efficiency

Parallel H.264/AVC Fast Rate-Distortion Optimized Motion Estimation using Graphics Processing Unit and Dedicated Hardware

Heterogeneous systems on a single chip composed of CPU, Graphical Processing Unit (GPU), and Field Programmable Gate Array (FPGA) are expected to emerge in near future. In this context, the System on Chip (SoC) can be dynamically adapted to employ different architectures for execution of data-intensive applications. Motion estimation is one such task that can be accelerated using FPGA and GPU for high performance H.264/AVC encoder implementation. In most of works on parallel implementation of motion estimation, the bit rate cost of motion vectors is generally ignored. On the contrary, this paper presents a fast rate-distortion optimized parallel motion estimation algorithm implemented on GPU using OpenCL and FPGA/ASIC using VHDL. The predicted motion vectors are estimated from temporally preceding motion vectors and used for evaluating the bit rate cost of the motion vectors simultaneously. The experimental results show that the proposed scheme achieves significant speedup on GPU and FPGA, and has comparable ratedistortion performance with respect to sequential fast motion estimation algorithm

Investigation of change in different properties of sandstone and dolomite samples during matrix acidizing using chelating agents

Properties of rock, such as effective porosity, permeability and pore size distribution (PSD), are generally referred to as petrophysical properties. These properties are among the most significant for reservoir evaluation. Acid stimulation treatments are usually used in sandstones to mitigate the impact of formation damage, with the aim of restoring or enhancing the natural matrix permeability and consequently boosting the well productivity. Hydrochloric acid (HCl) is commonly used in the preflush stage to remove calcium and other metal ions, preventing the development of calcium fluoride (CaF 2 ) and other silicate precipitates that could block the pore throats, while an acid mixture (HF–HCl combination) is usually preferred as the main stimulation fluid for the removal of quartz and remaining metal ions. However, sometimes the application of these acids can lead to other problems, including fast reactions, corrosion of pipes, environmental hazards, precipitation reactions and formation damage due to the incompatibility of HCl with clay minerals, so chelating agents have been proposed as an alternative for matrix stimulation fluids. In this study, three different chelating agents, ethylenediaminetetraacetic acid (EDTA), N-(2-hydroxyethyl) ethylenediamine-N,N′,N′-triacetic acid (HEDTA) and N-acetyl-l-glutamic acid (GLDA), have been used to stimulate Berea sandstone, Colton tight sandstone and Guelph dolomite samples. Core flood experiments were conducted on 1.5 × 3 (in 2 ) core plugs, at a temperature below 180 °F. A slow injection rate of (1–0.5 cc/min) was chosen for the treatment fluid, promoting the dissolution of ions by increasing the contact time between the fluid and the rock. Furthermore, nuclear magnetic resonance, wettability and micro-computed tomography (CT scan) analyses were employed to evaluate the effect of the acid treatment on formation properties such as porosity, PSD, pore topology, wettability and pore structure. After exposing the samples to HEDTA, large wormholes were detected in their pore network, demonstrating that HEDTA has the highest potential to create new pore spaces when compared to GLDA and EDTA when reacted with both types of samples

Institutional adversity, external knowledge sources, and new ventures' innovation: An institutional polycentrism theory perspective

Why do some new ventures thrive while others fail? In this study, we investigate the unique relationship between external knowledge sourcing of new ventures and its innovative outcomes, and its contextual embeddedness. The investigation is based on the Knowledge-based view and theory of institutional polycentrism across entrepreneurs, nested in different institutional contexts. Our framework generates hypothesis about the negative impact of higher levels of institutional adversity, on new venture's innovation at the national level. We then found the contingent role of adversity in institutions based on the relationship between external knowledge sourcing and new venture innovation. We examine this question using data from 28,660 entrepreneurs from 47 countries. We use Global Entrepreneurship Monitor, Freedom House, IEF, POLCON and Political Risk Services data for 2009–2013. We apply multilevel estimation framework to test our hypotheses. We find the new ventures that have high level of external knowledge sourcing tend to be more innovative: the ones that search widely through different external sources. Further, we find that the benefits to external knowledge sourcing depend on institutional environmental conditions, however new venture innovation should ensure the external knowledge sourcing are used robustly to develop a resource mechanism to deal with the institutional adversity

Hydrogen-rich syngas production from bi-reforming of greenhouse gases over zirconia modified Ni/MgO catalyst

Bi-reforming of methane (BRM) is gaining an increase interest due to the critical requirements to mitigate global warming and provide alternative energy resources. However, there has been a serious challenge to the scale-up of the process to commercial production due to the catalyst deactivation. In the present study, the influence of ZrO2 modifications on the activity and stability of MgO-supported Ni catalyst in the BRM reaction was investigated. The ZrO2-MgO mixed oxide support was prepared by co-precipitation method with variation in the ZrO2 composition and subsequently impregnated with Ni. The characterization of the freshly prepared Ni/MgO and Ni/MgO-ZrO2 catalysts using N2 physisorption analysis, X-Ray Diffraction (XRD), FESEM, XPS, H2-TPR, and CO2-TPD techniques revealed suitable physicochemical properties for the BRM reaction. The Ni/MgO-ZrO2 catalysts showed an improved performance in the BRM reaction in terms of activity and stability compared to the Ni/MgO at 800°C and CH4, H2O, CO2 ratio of 3:2:1, respectively. The best performance was obtained using the Ni/15%ZrO2-MgO for the BRM with CO2 and CH4 conversion of 81.5% and 82.5%, respectively. The characterization of the spent Ni/MgO catalyst using Raman spectroscopy, FESEM, and High Resolution Transmission Electron Microscopy (HRTEM) analysis revealed the formation of amorphous carbon that could be responsible for its fast deactivation

Oxidative Cleavage of Solbutamol by N- Chloro Saccharin in Aqueous Acetic Acid Medium

Kinetic oxidation of Salbutamol by N-Chlorosaccharin, in aqueous Acetic acid medium, shows first-order dependence on [NCSA] and [H+], and fractional order on [Solbutamol]. The variation of [H+] and [Sacharin](reaction product) has a remarked effect on the rate of reaction(rate decreases). Activation parameters for the reaction have been evaluated from the Arrhenius plot by studying the reaction at different temperatures. The stoichiometry was found to be 1:1, and the products of oxidation were found to be 3-hydroxy methyl,4-hydroxy benzene carbaldehyde, Saccharin) and territory ammine as bi-products. The rate law has been derived on the basis of experimental Kinetic data and a plausible mechanism has been proposed