High-power biofuel cells based on threedimensional reduced graphene oxide/ carbon nanotube micro-arrays

Miniaturized enzymatic biofuel cells (EBFCs) with high cell performance are promising candidates for powering next-generation implantable medical devices. Here, we report a closed-loop theoretical and experimental study on a micro EBFC system based on three-dimensional (3D) carbon micropillar arrays coated with reduced graphene oxide (rGO), carbon nanotubes (CNTs), and a biocatalyst composite. The fabrication process of this system combines the top–down carbon microelectromechanical systems (C-MEMS) technique to fabricate the 3D micropillar array platform and bottom–up electrophoretic deposition (EPD) to deposit the reduced rGO/CNTs/enzyme onto the electrode surface. The Michaelis–Menten constant KM of 2.1 mM for glucose oxidase (GOx) on the rGO/CNTs/GOx bioanode was obtained, which is close to the KM for free GOx. Theoretical modelling of the rGO/CNT-based EBFC system via finite element analysis was conducted to predict the cell performance and efficiency. The experimental results from the developed rGO/CNT-based EBFC showed a maximum power density of 196.04 µW cm−2 at 0.61 V, which is approximately twice the maximum power density obtained from the rGO-based EBFC. The experimental power density is noted to be 71.1% of the theoretical value

Modeling and Simulation of Enzymatic Biofuel Cells with Three-Dimensional Microelectrodes

The enzymatic biofuel cells (EBFCs) are considered as an attractive candidate for powering future implantable medical devices. In this study, a computational model of EBFCs based on three-dimensional (3-D) interdigitated microelectrode arrays was conducted. The main focus of this research is to investigate the effect of different designs and spatial distributions of the microelectrode arrays on mass transport of fuels, enzymatic reaction rate, open circuit output potential and current density. To optimize the performance of the EBFCs, numerical simulations have been performed for cylindrical electrodes with various electrode heights and well widths. Optimized cell performance was obtained when the well width is half of the height of the 3-D electrode. In addition, semi-elliptical shaped electrode is preferred based on the results from current density and resistive heating simulation

Entropy-Based Complexity Metrics for Coal Resource Consolidation System Engineering

AbstractBased on the basic principle of management entropy theory, this paper constructs a metric scale and entropy-based quantization model for evaluating the complexity of resource consolidation system engineering. Under the transformed structure of coal resource consolidation system of Shanxi Province and the constructed relation mode, the proposed model is put in practice to analyze and evaluate the complexity of Shanxi coal resources consolidation system. The results show that by importing material, energy and information, the complex system evolves to the direction of order and dynamic balance

Research Progress and Development of Sapphire Fiber Sensor 1

Abstract: Sapphire fiber thermometers have become a new potential option in the field of high-temperature measurements. Recent research progress of sapphire fiber sensors is summarized; operational principles, advantages, disadvantages, and applications of sapphire fiber sensors are introduced. Research has shown that sapphire fiber sensors can be used to accurately measure very high temperatures in harsh environments and has been widely applied in fields such as aviation, metallurgy, the chemical industry, energy, and other high temperature measurement areas. Sapphire optical fiber temperature measurement technology will move toward miniaturization, intelligence following the advances in materials, micro-fabrication and communication technologies. Copyright © 2014 IFSA Publishing, S. L

Past studies and potential measures for rehabilitation of the shallow lake (Lake Ludas)

Lake Ludaš has been under a strong anthropogenic influence for a very long time, so the history of fruitful scientific investigation was very often connected with the evaluation of a human impact and potential rehabilitation measures. Unfortunately, attempts to improve the lake's natural status remain more in the field of theoretical models than concrete practical solutions. Aiming to better understand the potential of different rehabilitation measures for Lake Ludaš, we combined our ecological analyses (unpublished results) and the literature survey. The continuous massive cyanobacterial bloom and the formation of a thick sediment layer rich in different organic and inorganic pollutants represent two major challenges in the lake's rehabilitation. The unknown ecological role of invasive species that have already colonised Lake Ludaš will make the attempts to improve conditions in the lake even more challenging. The reduction of nutrient load, changes in the intensity and directions of water circulation, as well as top sediment layer removal in the lake, are measures under consideration for several decades. But their combination, order of implementation and possibilities of successful execution are still under debate. However, there is no doubt that the restoration of a natural hydrological regime should be a key step in the rehabilitation of Lake Ludaš

Rapid approach for cloning bacterial single-genes directly from soils

Obtaining functional genes of bacteria from environmental samples usually depends on library-based approach which is not favored as its large amount of work with small possibility of positive clones. A kind of bacterial single-gene encoding glutamine synthetase (GS) was selected as example to detect the efficiency of cloning strategy in this study. Five GS genes were directly cloned from soils using degenerate primers with two steps of nested polymerase chains reactions. The genes showed 94 to 99% amino acid identities to the homologs in the known database, and encoded proteins affiliated to GS I and GS II families, respectively. All the five genes could rescue the growth of Escherichia coli glutamine auxotroph mutant ET6017 in minimum medium (ammonium chloride was sole nitrogen source in this medium). This study develops one rapid approach for cloning bacterial single-genes directly from soils. Comparing with the conventional strategies for gene cloning from complex environmental samples, this method did not need making genomic library and isolating target genes from large amount of library clones. This approach distinctively demonstrates its advantages of rapidity and effectiveness particularly when it aims at cloning short single-genes that had known homologs in all kinds of nucleic acid databases.Keywords: Gene cloning, soil, glutamine synthetase, nested PCR, single-geneAfrican Journal of Biotechnology Vol. 12(32), pp. 5029-503