High temperature kinetics of metal-oxygen reactions by solid oxide electrolyte cells: An application to nickel

Chronopotentiometric curves, generated by galvanostatic single steps, applied to a solid electrolyte cell, have been analysed on the basis of a dimensionless equation derived on the assumption that a scale of oxide grows at one of the electrode-electrolyte interfaces. This process is rate limiting for developing the charge transfer-diffusion overvoltage; Wagner's theory on tarnishing, under retarding electric field conditions, has been assumed for treating the kinetics of the growing scale. The kinetic model developed has been tested for the reaction of solid nickel (positive electrode) at 1268 K with oxygen partial pressures ranging from 3.9 × 10^?11 Atm [equilibrium pressure of Ni(s)-NiO(s) system] to 1.7 × 10^?10 Atm.Both the rate and the rate constant of the scale formation go through the maximum but at different times, while the rate constant dependence of the oxygen partial pressure agrees with the theory. The maximum rate constant value was found to be 9.8 × 10⁸ molecules cm^?1 s^?1. The calculated scale thicknesses were between 6 and 24 nm.     

Numerical simulation of unsteady continuous countercurrent adsorption system with nonlinear adsorption isotherm

A theoretical dispersed plug flow model that includes a mass-transfer resistance represented by a linear driving force approximation is developed for unsteady-state continuous countercurrent adsorption systems having nonlinear equilibrium isotherms. The model is solved from unsteady state to steady state using Danckwert's boundary conditions. The system consists of two sections having 11 adsorption columns. The model is used to investigate the effects of various process parameters on the performance of the system. It is demonstrated that as the nonlinearity changes, the optimal choice of bed length, feed and eluent flow rates, and switch times must be suitably adapted. The results are compared with the “pore diffusion” and “equilibrium” models of Morbidelli et al.¹⁴ and are found to lie between these two models. To establish the consistency of the model the results are compared with one of the limiting asymptotes, namely, the linear isotherm with the experimental data of Ching and Ruthven^12,13 and are found to agree well.     

Interaction rules underlying group decisions in homing pigeons

Travelling in groups gives animals opportunities to share route information by following cues from each other''s movement. The outcome of group navigation will depend on how individuals respond to each other within a flock, school, swarm or herd. Despite the abundance of modelling studies, only recently have researchers developed techniques to determine the interaction rules among real animals. Here, we use high-resolution GPS (global positioning system) tracking to study these interactions in pairs of pigeons flying home from a familiar site. Momentary changes in velocity indicate alignment with the neighbour''s direction, as well as attraction or avoidance depending on distance. Responses were stronger when the neighbour was in front. From the flocking behaviour, we develop a model to predict features of group navigation. Specifically, we show that the interactions between pigeons stabilize a side-by-side configuration, promoting bidirectional information transfer and reducing the risk of separation. However, if one bird gets in front it will lead directional choices. Our model further predicts, and observations confirm, that a faster bird (as measured from solo flights) will fly slightly in front and thus dominate the choice of homing route. Our results explain how group decisions emerge from individual differences in homing flight behaviour.     

Failure Prediction,Lead Time Estimation and Health Degree Assessment for Hard Disk Drives Using Voting Based Decision Trees

Hard Disk drives (HDDs) are an essential component of cloud computing and big data, responsible for storing humongous volumes of collected data. However, HDD failures pose a huge challenge to big data servers and cloud service providers. Every year, about 10% disk drives used in servers crash at least twice, lead to data loss, recovery cost and lower reliability. Recently, the researchers have used SMART parameters to develop various prediction techniques, however, these methods need to be improved for reliability and real-world usage due to the following factors: they lack the ability to consider the gradual change/deterioration of HDDs; they have failed to handle data unbalancing and biases problem; they don’t have adequate mechanisms for health status prediction of HDDs. This paper introduces a novel voting-based decision tree classifier to cater failure prediction, a balance splitting algorithm for the data unbalancing problem, an advanced procedure for lead time estimation and R-CNN based approach for health status estimation. Our system works robustly by considering a gradual change in SMART parameters. The system is rigorously tested on 3 datasets and it delivered benchmarks results as compared to the state of the art.     

Stand-alone and network capable pocket radiation detection system

A multi-functional and networked pocket radiation detection system has been developed at the Idaho National Laboratory (INL) capable of detecting and storing gamma ray and neutron data. The device can be used as a stand-alone device or in conjunction with an array to cover a small or large area. The device has programmable alarm trigger levels that can be modified for specific applications. The data are stored with a date/time stamp and can be transferred and viewed on a PDA via direct connection or, in networked configuration, wireless connection to a remote central facility upon request. Data functional/bench tests have been completed successfully and the device was demonstrated to detect radiation from a 55.6 μCi ²⁵²Cf source at 5 m and from 1.4 mCi ²⁵²Cf source at 10 m which exceeds both ANSI and IAEA standards for pocket radiation detection. In terms of sensitivity, this detection system detects neutron and gamma-ray fields down to 10 μrem/h levels and therefore can find the location of the radioactive source quickly. The detection system is small enough to be put in a pocket or clipped to a belt.     

A CAD/CAM system for process planning and optimization in LOM (Laminated Object Manufacturing)

Rapid Prototyping (RP) technologies have emerged as a powerful set of manufacturing technologies in recent years. While these technologies invariably provide tremendous time savings over traditional methods for the manufacture of design prototypes, most are still quite inefficient. This paper proposes two ideas: (i), that these processes can be significantly optimized by using better process planning; and (ii), that several of these technologies use similar core planning technologies for optimization. The first hypothesis is verified in this paper by presenting an improved process planning system for one RP technology, Laminated Object Manufacturing (LOM). The second observation led us to develop an open architecture planning system for a host of RP technologies. A testbed software system using these ideas has been developed and is presented in this paper. While the methodologies developed can work with the current industry standard STL format for storing object CAD data, the software is planned purely to work using exact solid models and direct slicing methods.     

AN INTERACTIVE HYBRID (SYMBOLIC-NUMERIC) SYSTEM APPROACH TO NEAR OPTIMAL DESIGN OF MECHANICAL COMPONENTS

A hybrid (symbolic-numeric) system, referred to as OPTDEX, (OPTIMAL DESIGN EXPERT) for the optimal design or mechanical components and systems has been developed. The system is written in Golden Common LISP and IBM Professional (Ryan-McFarland) FORTRAN for execution on the IBM PC/AT microcomputer. Graphical output has been implemented using the Graphical Kernel System (GKS) standard. This microcomputer-based implementation makes the system particularly attractive as an easily accessible, low cost engineering analysis and design tool.

Experience with the system indicates that the time required to achieve, at least, partially optimized engineering design solutions is similar to that which may be expected with standard, nonoptimization-based, microcomputer computation. Any added computational time may be justified and subsequently offset by increased long term design efficacy.     

Decision model for partnership development in virtual enterprises

A virtual enterprise has been considered as a temporary consortium of companies. Recently, researchers have investigated virtual enterprises from various perspectives, such as business activities and workflows, information exchanges and their standards, organizational behaviours between companies, etc. However, real collaborative activities among companies in a virtual enterprise cannot be done before a partnership is developed among companies. Besides, though partnership is important in virtual enterprises, a decision model for partnership development is seldom studied. This research develops a decision model from a micro view (i.e. from a company's perspective). A company may use the model to specify its current partnership strategy and determine its future partnership strategy with another company. Four factors are considered in the model: the format of the relationship with suppliers, the number of suppliers, the type of service provided by suppliers and the method of service delivery from suppliers. However, a partnership strategy has to be updated based on internal and external changes. This research finds out that six factors are associated with a change on partnership. With those factors, a decision process is developed for a company to update its partnership strategy. The partnership of IBM to Acer is also investigated to illustrate the application of the model. The results validate the applicability of the decision model.     

Dams and Floods

The possible mitigation of floods by dams and the risk to dams from floods are key problems. The People’s Republic of China is now leading world dam construction with great success and efficiency. This paper is devoted to relevant experiences from other countries, with a particular focus on lessons from accidents over the past two centuries and on new solutions. Accidents from floods are analyzed according to the dam’s height, storage, dam material, and spillway data. Most of the huge accidents that have been reported occurred for embankments storing over 10 hm³. New solutions appear promising for both dam safety and flood mitigation.     

Storage of Mechanical Energy Based on Carbon Nanotubes with High Energy Density and Power Density

Energy storage in a proper form is an important way to meet the fast increase in the demand for energy. Among the strategies for storing energy, storage of mechanical energy via suitable media is widely utilized by human beings. With a tensile strength over 100 GPa, and a Young's modulus over 1 TPa, carbon nanotubes (CNTs) are considered as one of the strongest materials ever found and exhibit overwhelming advantages for storing mechanical energy. For example, the tensile‐strain energy density of CNTs is as high as 1125 Wh kg^‐1. In addition, CNTs also exhibit great potential for fabricating flywheels to store kinetic energy with both high energy density (8571 Wh kg^‐1) and high power density (2 MW kg^‐1 to 2 GW kg^‐1). Here, an overview of some typical mechanical‐energy‐storage systems and materials is given. Then, theoretical and experimental studies on the mechanical properties of CNTs and CNT assemblies are introduced. Afterward, the strategies for utilizing CNTs to store mechanical energy are discussed. In addition, macroscale production of CNTs is summarized. Finally, future trends and prospects in the development of CNTs used as mechanical‐energy‐storage materials are presented.     

Rapid Measurements of Thermodynamic Properties for Alternative Refrigerants with Vibrating-Tube Densimeter

More than 2000 PVT data in the liquid phase, vapor phase, and at saturation boundaries have been obtained for pure compounds of several alternative refrigerants. In addition, more than 1000 liquid-density data have been obtained for several binary and ternary mixtures. The alternative refrigerants measured in the present study include CF₃OCH₃ (trifluoromethyl methyl ether) and CF₃CF₂OCH₃ (pentafluoroethyl methyl ether), which are hydrofluoroethers developed by RITE (the Research Institute of Innovative Technology for the Earth, Japan), and typical hydrocarbons, such as propane, n-butane, isobutene, and their binary and ternary mixtures. The measurement uncertainties are estimated to be 3 to 7mK for temperature, 0.26kPa or 0.022% whichever is greater for pressure, and 0.07 kg ·m³ or 0.024% whichever is greater for density. The present measurement system took only a few minutes to get one PVT datum, and one or two days to complete all the measurements for a single fluid at temperatures from 240 to 380\,K and at pressures up to 7\,MPa. In addition, an empirical equation of state (EoS) for the liquid phase was developed on the basis of the present data, and the EoS nicely reproduces not only the present data but also existing data reported by other researchers.Paper presented at the Fifteenth Symposium on Thermophysical Properties, June 22–27, 2003, Boulder, Colorado, U.S.A.     

HTR-10燃料元件装卸控制模拟装置的研制

在研制以ＬＣ－ＩＰＣ为核心的高温气冷实验堆燃料元件装卸控制系统的过程中,设计了燃料元件装卸控制模拟装置,文中介绍了装置结构,现场信号及执行模拟运行实现方式。实现了燃料元件装卸循环过程模调试控制、状态监控、等功能。     

Tolerance specification and comparative analysis for computer-integrated dimensional inspection

Two important issues in the development of a computer-integrated dimensional inspection environment for manufactured parts are described, namely tolerance specification and comparative analysis. These two issues are related directly and therefore, should be addressed together. For supporting the computer-integrated dimensional inspection, a geometric dimensioning and tolerancing (GD&T) specification module and a comparative analysis module are developed and integrated with CATTA of the IBM CAD/CAM system. The proposed specification module supports ISO and ANSI geometric tolerances and allows multiple tolerance assignments on each single feature as well as on a group of same pattern features. Using this specification module, various tolerance information can be directly specified to the 3D CAD model of a part and can be used to support the subsequent planning and operation for manfacturing and inspection. The comparative analysis module is created to work with the GD&T module for constructing datum reference frames and comparing the actual measurement data with nominal design. After specifying all necessary tolerance information, using discrete measurement data from coordinate measuring machines (CMM), one can evaluate the dimensional quality of an actual feature through the comparative analysis module.     

New mass transfer performance data of a cross-flow liquid desiccant dehumidification system

This paper presents new mass transfer performance data of a cross-flow liquid desiccant dehumidification system using a structured packed tower. The structured packing consists of cross-corrugated cellulose paper sheets with a surface area per unit volume ratio of 608 m² m^?3. The liquid desiccant, viz. calcium chloride, flows through the pad from top to bottom, while the air flows horizontally making it a cross-flow configuration. The experimental dehumidification effectiveness from the present study was compared with the widely used Chung's correlation (although developed for counter flow arrangement, as opposed to cross-flow in the current study) and Liu et al.'s correlation. A new empirical correlation was developed for the dehumidification effectiveness, which fitted the experimental data to within ±10%. The effect of varying air and solution inlet conditions and flow rates on the system performance was also quantified in the paper.     

OREX-J: towards a universal software framework for the experimental analysis of optimization algorithms

The Operations Research EXperiment Framework for Java (OREX-J) is an object-oriented software framework that helps users to design, implement and conduct computational experiments for the analysis of optimization algorithms. As it was designed in a generic way using object-oriented programming and design patterns, it is not limited to a specific class of optimization problems and algorithms. The purpose of the framework is to reduce the amount of manual labor required for conducting and evaluating computational experiments: OREX-J provides a generic, extensible data model for storing detailed data on an experimental design and its results. Those data can include algorithm parameters, test instance generator settings, the instances themselves, run-times, algorithm logs, solution properties, etc. All data are automatically saved in a relational database (MySQL, http://www.mysql.com/) by means of the object-relational mapping library Hibernate (http://www.hibernate.org/). This simplifies the task of analyzing computational results, as even complex analyses can be performed using comparatively simple Structured Query Language (SQL) queries. Also, OREX-J simplifies the comparison of algorithms developed by different researchers: Instead of integrating other researchers’ algorithms into proprietary test beds, researchers could use OREX-J as a common experiment framework. This paper describes the architecture and features of OREX-J and exemplifies its usage in a case study. OREX-J has already been used for experiments in three different areas: Algorithms and reformulations for mixed-integer programming models for dynamic lot-sizing with substitutions, a simulation-based optimization approach for a stochastic multi-location inventory control model, and an optimization model for software supplier selection and product portfolio planning.     

Spatial moment dynamics for collective cell movement incorporating a neighbour-dependent directional bias

The ability of cells to undergo collective movement plays a fundamental role in tissue repair, development and cancer. Interactions occurring at the level of individual cells may lead to the development of spatial structure which will affect the dynamics of migrating cells at a population level. Models that try to predict population-level behaviour often take a mean-field approach, which assumes that individuals interact with one another in proportion to their average density and ignores the presence of any small-scale spatial structure. In this work, we develop a lattice-free individual-based model (IBM) that uses random walk theory to model the stochastic interactions occurring at the scale of individual migrating cells. We incorporate a mechanism for local directional bias such that an individual''s direction of movement is dependent on the degree of cell crowding in its neighbourhood. As an alternative to the mean-field approach, we also employ spatial moment theory to develop a population-level model which accounts for spatial structure and predicts how these individual-level interactions propagate to the scale of the whole population. The IBM is used to derive an equation for dynamics of the second spatial moment (the average density of pairs of cells) which incorporates the neighbour-dependent directional bias, and we solve this numerically for a spatially homogeneous case.     

Generalization of experimental data on internal heat transfer in porous structures

Experimental data are analyzed and generalized, which were obtained at Joint Institute for High Temperatures of the Russian Academy of Sciences (OIVT RAN) for internal heat transfer to single-phase heat-transfer agent in porous structures of various classe s such as sintered spheres, multilayer reticular materials, and matted and highly porous cellular materials in a wide range of values of Peclet number from 10^-3 to 440 when using water, air, steam, and other heat-transfer agents as cooling agents. The results are compared with experimental data of other researchers to produce adequate agreement between them.     

A Changeable Scale Value Model for Rank Order Data

A generalized version of Takane and Carroll’s (1981) (Psychometrika, 46, 389–405) scaling model is developed to analyze rank order data. This model assigns to each stimulus n (the number of stimuli) different scale values each of which is to be utilized at its respective occasion of successive first choice in the ranking task. The n scale values assigned to a stimulus is predicted by using the cumulative binominal distribution function for an assumed set of n−1 Bernoulli trials of a simple judgment about the same attribute of that stimulus as is to be scaled from the ranking data. Examples of the application of the model are reported. They have demonstrated that the generalized model can account for all the data sets examined better than the original one.

     

Full scale Reynolds number effects for the viscous flow around the ship stern

We calculate the stern flow for the case of HSVA ship model at two different Reynolds number; one is Re=10⁹ for full scale and the other is Re=5×10⁶ for model scale. And we investigate the trend of scale effect on the stern flow by comparing the results of two calculations. The STERN/NS computer program, developed for solving the Navier-Stokes equations in a numerically generated general coordinate, is used with k– turbulence model for turbulent flows. At full scale, skin frictions are much reduced as expected from boundary layer concept, and the pressure in the thick boundary layer region around the stern and near wake is noticeably changed by decreasing of viscous-inviscid interaction in flow domain. At the propellar plane, full scale solutions show that the velocities in the shear layer increase and the wake region is substantially reduced by 20% compared with the model scale solutions.