In this paper, we are proposing a new algorithm that improves the performance of the DBSCAN clustering algorithm using a packed X-tree. The proposed algorithm does not require the minpoints and eps values. We have extensively described how the system is achieved and we have also proposed a new effective method for finding the knearest neighbours of spatial objects in a large database. The study shows that the proposed method is very efficient and will greatly accelerate the operations of density based clustering in large dataset as against the existing methods.
Many efforts are being made to tune perovskite thin film cathodes toward improving their oxygen reduction kinetics and thereby improving overall solid oxide fuel cell performance. One approach is to enhance oxygen diffusion via introduction of larger concentrations of grain boundaries during thin film growth. While such grain boundary engineering has been shown to enhance ionic transport and surface reaction kinetics in some cases, little attention has been paid on its corresponding influence on electronic conductivity. To provide insights into the role of grain boundaries and their contribution to the cathode performance, we have investigated separately the electronic and ionic conductivity of La 0.8 Sr 0.2 MnO 3 (LSM) thin films by Van-der-Pauw and 18 O tracer exchange measurements respectively, as well as their combined contributions by electrochemical impedance spectroscopy. All three types of experiments were performed on the same kind of samples with varying LSM microstructure to illustrate the effects of grain boundaries on both electron and ion conduction. Correlations between active electrode area and microstructure-dependent partial conductivities are presented. The findings can also be used for optimizing current collector spacing in thin film solid oxide fuel cells.©The
Solid state electrolyte systems boasting Li+ conductivity of >10 mS cm−1 at room temperature have opened the potential for developing a solid state battery with power and energy densities that are competitive with conventional liquid electrolyte systems. The primary focus of this review is twofold. First, differences in Li penetration resistance in solid state systems are discussed, and kinetic limitations of the solid state interface are highlighted. Second, technological challenges associated with processing such systems in relevant form factors are elucidated, and architectures needed for cell level devices in the context of product development are reviewed. Specific research vectors that provide high value to advancing solid state batteries are outlined and discussed.
Mechanical and electrochemical phenomena are coupled in defining the battery reliability, particularly for solid-state batteries. Micro-cracks act as barriers to Li-ion diffusion in the electrolyte, increasing the average electrode's tortuosity. In our previous work, we showed that solid electrolytes are likely to suffer from mechanical degradation if their fracture energy is lower than 4 J m(-2) [G. Bucci, T. Swamy, Y.-M. Chiang, and W. C. Carter, J. Mater. Chem. A (2017)]. Here we study the effect of electrolyte micro-cracking on the effective conductivity of composite electrodes. Via random analyzes, we predict the average diffusivity of lithium in a solid-state electrode to decrease linearly with the extension of mechanical degradation. Furthermore, the statistical distribution of first passage times indicates that the microstructure becomes more and more heterogeneous as damage progresses. In addition to power and capacity loss, a non-uniform increase of the electrode tortuosity can lead to heterogeneous lithiation and further stress localization. The understanding of these phenomena at the mesoscale is essential to the implementation of safe high-energy solid-state batteries. (C) The Author(s) 2017. Published by ECS. All rights reserved.
Rural Kiosks are important infrastructural pillar in rural regions for internet and basic technology facility all around the world. They are also known as Tele-centers or Common Service Centers and are majorly used by government to promote Electronic Governance. The major characteristic of setting up of Rural Kiosk is their appropriate location so that people from rural region can avail the services at minimum travel cost and time. There are lot of traditional schemes used by researchers in past for location allocation but this paper proposes the usage of Fuzzy C-Means clustering and BAT algorithm to optimize the location of Rural Kiosk. The meta-heuristic approach has produced better results as compared to normal graph theories in past. The experiment has been conducted on a random data set of 72 village locations from India and their clusters are formed. It is found that using only Fuzzy C-Means clustering to allocate the center and by using it in combination with BAT algorithm produced up to 25% of efficient results. This can drastically help the key stakeholders in allocation of these Rural Kiosks at right places so as to maximize their utility.
An accurate, comprehensive model for the individual and simultaneous electro-oxidation of H-2 and CO on Ni-YSZ is necessary to predict SOFC performance for a range of gaseous fuels. A mechanism that combines hydrogen (H) spillover to YSZ with oxygen (O) spillover to nickel is implemented in a previously-validated 1D-MEA model with detailed gas-phase transport and surface reforming kinetics in the anode. This model is then successfully fitted to a wide range of experimental polarization data for fuel mixtures. The H and O spillover pathways are then investigated in depth for two anode fuel mixtures: 20% H-2 + 80% N-2 and 20% H-2 + 80% CO. Although these studies confirm that H spillover is typically the dominant source of current, they also show that the current produced by O spillover is non-negligible at higher currents. Furthermore, it is observed that H-2 adsorption to nickel becomes the rate-limiting step at high currents in the hydrogen pathways, while the current produced by O spillover to CO(Ni) is never limited by the rate of CO adsorption. The model is then successfully compared to two independent lower temperature data sets. Together these results demonstrate that it is important to model both spillover pathways on Ni/YSZ and to account for rate-limiting H-2 adsorption at high currents. (C) The Author(s) 2016. Published by ECS. All rights reserved.
The potential of anion exchange membrane (AEM) fuel cells to provide inexpensive compact power from a wider variety of fuels than is possible with a proton exchange membrane (PEM) fuel cell, has continued to drive the research interest in this area. Alkaline catalysis in fuel cells has been demonstrated with non-precious metal catalysts, and with a variety of fuels beyond H2and methanol. Alkaline fuel cells (AFCs), based on aqueous solutions of KOH, have serious drawbacks associated with system complexity and carbonate formation. Anion exchange membrane (AEMs) fuel cells have a number of advantages over both PEM fuel cells and traditional AFCs; however, ionic conductivity in AEMs is still lower than PEMs and chemical stability of membrane attached cations in hydroxide is still not sufficient for practical applications. Our goal is to synthesize an AEM with excellent anion transport properties that can be fabricated into a thin robust film suitable for fuel cell applications. To do this with have started with polymer architectures based on homo- and co-polymers of vinylbenzyltrimethylammonium, PVBTMA, as these are readily synthesized as organized or random diblock polymers, which we can fully characterize, use for the study of anionic transport and build in-silico so that predictive modeling can be used to design next generation materials. Block copolymers that can self-assemble into well-defined hydrophobic and hydrophilic domains will better be able to achieve the stringent requirements for excellent AEM fuel cells. Membranes made from block copolymers will provide well-oriented and continuous conductive hydrophilic channels to enhance ion conductivity. Because of the presence of the hydrophobic domain in the membranes, the mechanical property of the membranes can also be enhanced. Therefore, high IEC can be achieved leading to higher conductivity. In contrast to random copolymers, it is difficult to achieve high IEC because of the associated swelling encountered at high states of hydration resulted in disintegration of the membranes. By using block copolymers containing polycation as AEMs, the relationship between structure and ionic conductivity of the membranes can be investigated as well. Several studies about structure-morphology-property relationships of block copolymers for PEM have shown that the morphology of the conductive membranes strongly influences their proton conductivity on the aspect of type and orientation of structure. We studied water partitioning in PVBTMA diblock copolymers with alternating hydrophobic lamellae (for structural support) and hydrophilic lamellae (to conduct ions). In order to be conductive, the hydrophilic block must absorb water. The water is often thought of as uniformly permeating the hydrophilic lamella, but that need not be so. Since the hydrophilic block is effectively tethered to the hydrophilic-hydrophobic interface, the polymers must stretch on average to accommodate the water. For typical well-solvated grafted layers the optimal stretching profile leads to strongly non-uniform swelling with solvent. In a simple example the polymer concentration decreases quadratically with the distance z from the tethering surface and reaches zero at a specific height h set by the solvent quality and the elastic properties of the polymer coils. Likewise for weaker solvation, there will be more polymer near the hydrophilic-hydrophobic interface, and more water at the midplane. This nonuniformity takes a special form for marginal solvation, where two concentrations exist in equilibrium. Here the tethering constraint favors the polymer-rich phase to reside near the tethering surface, while the dilute phase occupies a “water channel" near the midplane. The water configuration has potential implications for the ion conductivity of the membrane. The polymer-rich region is packed with ions (good for conductivity), but the small amount of water there inhibits ion mobility (bad for conductivity). In the water channel, this tradeoff is reversed. The consequences of this for ionic conductivity will be discussed.
The use of Graphics Processing Units (GPUs) has recently witnessed ever growing applications for different computational analyses in the field of Life Sciences. In this work we present a CUDA-powered computational tool, named coagSODA, that was purposely developed and applied for the analysis of a large model of the blood coagulation cascade defined as a system of ordinary differential equations, based on both mass-action kinetics and Hill functions. We discuss the biological results of the parameter sweep analyses of this model, and show that GPUs can boost the computational performances up to 177x speedup.
The development of new materials for secondary batteries is nowadays one of the most active fields in the international scientific panorama [1]. The state of the art for liquid electrolytes in a lithium-ion cell is typically a mixture of organic carbonates such as ethylene carbonate (EC) or dimethyl carbonate (DMC). The mixture ratio varies depending upon the desired cell properties. These solvents contain solvated lithium ions. The latter are provided by lithium salts, most commonly lithium hexafluorophosphate (LiPF 6 )[2]. Despite the high conductivity of these electrolytes (s >10 -3 S·cm -1 at RT), important drawbacks are associated with the volatility and flammability of liquid solvents and the chemical instability of the LiPF 6 salt. The latter undergoes hydrolysis in the presence of water traces, releasing fluoride anions. [3] Ionic liquids (ILs) are salts with melting temperatures lower than 100°C. When they are liquid at room temperature, ILs are classified as room temperature ILs (RTILs). Some typical properties of ILs are: a) a low volatility, a high thermal stability and a negligible flammability; b) a high ion density and conductivity; c) a wide electrochemical stability window; and d) a simple synthesis, carried out by choosing the cation and anion which best comply with the requirements of the intended application. These features make ILs very suitable as solvents in electrolytes for Li batteries[4]. Recently, a class of solid-state single-ion conducting materials based on lithiated fluorinated-TiO 2 (LiFT) was proposed, which demonstrated its applicability as a nanofiller to obtain nanocomposite polymer electrolytes [5,6]. LiFT consists of fluorinated anatase nanoparticles that are directly surface-functionalized with Li + through an innovative one-step reaction with molten metallic lithium[7]. The conductivity of LiFT is due to Li + hopping processes between coordination sites present at the nanoparticle grain boundaries. These latter events take place in a very effective way. The use of LiFT nanoparticles as the source of Li + ions and ILs as the plasticizing agents allowed us to obtain innovative composite electrolytes for application in lithium batteries with a high thermal stability and conductivity. Indeed, the use of imidazolium ILs based on TFSI - and BF 4 - anions allowed us to investigate the different ability of these anions to coordinate and dissociate the Li + cations present on the surface of LiFT nanoparticles. For these reasons it has to be highlighted that no conventional Li salts are used in the electrolytes here proposed. In this report, composite electrolytes based on LiFT nanopowder, 1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF 4 ) and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMImTFSI) ILs are proposed. In details, LiFT nanopowder is doped with a known amount of both ILs to obtain two types of electrolytes with formula LiFT/EMImTFSI 0.118 and LiFT/EMImBF 4 0.200 . The resulting electrolytes contain around 25% wt of ILs and show a powder-like consistence. The correlation between structure, thermal properties and conductivity mechanisms of the resulting LiFT/EMImTFSI 0.118 and LiFT/EMImBF 4 0.200 electrolytes is investigated by a variety of techniques: (a) FT-MIR and FIR at different temperatures; (b) Differential Scanning Calorimetry (DSC); (c) Thermogravimetric Analysis (TGA); and (d) Broadband Electrical Spectroscopy (BES). The materials are thermally stable up to 250°C and their conductivities at 30 and 130°C are, respectively, of 1.2x10 -2 cm -1 and 4.1x10 -2 Scm -1 for LiFT/EMImTFSI 0.118 and 1.7x10 -3 Scm -1 and 1.7x10 -2 Scm -1 , for LiFT/EMImBF 4 0.200 . Finally, the performance of the proposed materials, tested in operating CR2032 coin cells by galvanostatic cycling in a Li 4 Ti 5 O 12 /{LiFT/EMImTFSI 0.118 }/LiCoO 2 configuration is shown in Figure 1. Figure 1 Discharge profiles (inset) and capacity vs. cycle number for a Li 4 Ti 5 O 12 / {LiFT/EMImTFSI 0.118 }/LiCoO 2 , CR2032, coin cell (discharge plotted as negative current). References [1] V. Di Noto, S. Lavina, G.A. Giffin, E. Negro, B. Scrosati, Polymer electrolytes: Present, past and future, Electrochim. Acta. 57 (2011) 4–13. [2] K. Xu, Nonaqueous Liquid Electrolytes for Lithium-Based Rechargeable Batteries, Chem. Rev. 104 (2004) 4303–4418. [3] C. Mikolajczak, M. Kahn, K. White, R.T. Long, Lithium-Ion Batteries Hazard and Use Assessment, Springer US, Boston, MA, 2011. [4] M. Armand, F. Endres, D.R. MacFarlane, H. Ohno, B. Scrosati, Ionic-liquid materials for the electrochemical challenges of the future, Nat. Mater. (2009) 621–629. [5] F. Bertasi, K. Vezzù, E. Negro, S. Greenbaum, V. Di Noto, Single-ion-conducting nanocomposite polymer electrolytes based on PEG400 and anionic nanoparticles: Part 1. Synthesis, structure and properties, Int. J. Hydrogen Energy. 39 (2013) 2872–2883. [6] F. Bertasi, K. Vezzù, G.A. Giffin, T. Nosach, P. Sideris, S. Greenbaum, et al., Single-ion-conducting nanocomposite polymer electrolytes based on PEG400 and anionic nanoparticles: Part 2. Electrical characterization, Int. J. Hydrogen Energy. 39 (2013) 2884–2895. [7] V. Di Noto, F. Bertasi, E. Negro, M. Piga, M. Bettiol, F. Bassetto, Solid-state electrolytes based on fluorine-doped oxides, PCT/IB2012/053542, 2013.
This prototype development explains the challenges encountered during the ISO/IEEE 11073 standard implementation process. The complexity of the standard and the consequent heavy requirements, which have not encouraged software engineers to adopt the standard. The developing complexity evaluation drives us to propose two possible implementation strategies that cover almost all possible use cases and eases handling the standard by non-expert users. The first one is focused on medical devices (MD) and proposes a low-memory and lowprocessor usage technique. It is based on message patterns that allow simple functions to generate ISO/IEEE 11073 messages and to process them easily. MD act as X73 agent. Second one is focused on more powerful device X73 manager, which do not have the MDs' memory and processor usage constraints. The protocol between Agent and Manager is point-to-point and we can distribute the functionality between devices. Developed both implementation X73 Agent and Manager will cut developing time for applications based on ISO/EEE 11073. Keys words: ISO/EEE 11073, ECG, home monitoring system, personal distance healthcare
Census in most countries has been faced with various natural and human made barriers. Thus, the aim of this research is to develop a systematic, coordinated, and responsive database which will adequately interact with a web application by harnessing the strengths of computational science and biometrics. The programming language employed in the development of this web-based application was the C#.NET programming language. Microsoft Visual Studio was used as an integrated environment for the development of this tool. Microsoft SQL Server (2005) served as a relational database management application for handling the data used in this research. From the results obtained from this research work, it had shown that with design and implementation of a secured system information countries can make informed decisions for effective policy, planning and management of their everincreasing populace and economy. Keyword: Census, Census information management, programming, biometrics
