bluuebunny/crossref_metadata_2025 huggingface dataset:
Robust tracking and remapping of eye appearance with passive computer vision
Authors: Colombo Carlo , Comanducci Dario , Bimbo Alberto Del
Published: January 2008

A single-camera iris-tracking and remapping approach based on passive computer vision is presented. Tracking is aimed at obtaining accurate and robust measurements of the iris/pupil position. To this purpose, a robust method for ellipse fitting is used, employing search constraints so as to achieve better performance with respect to the standard RANSAC algorithm. Tracking also embeds an iris localization algorithm (working as a bootstrap multiple-hypotheses generation step), and a blink detector that can detect voluntary eye blinks in human-computer interaction applications. On-screen remapping incorporates a head-tracking method capable of compensating for small user-head movements. The approach operates in real time under different light conditions and in the presence of distractors. An extensive set of experiments is presented and discussed. In particular, an evaluation method for the choice of layout of both hardware components and calibration points is described. Experiments also investigate the importance of providing a visual feedback to the user, and the benefits gained from performing head compensation, especially during image-to-screen map calibration.
Using geometric properties of topographic manifold to detect and track eyes for human-computer interaction
Authors: Wang Jun , Yin Lijun , Moore Jason
Published: January 2008

Automatic eye detection and tracking is an important component for advanced human-computer interface design. Accurate eye localization can help develop a successful system for face recognition and emotion identification. In this article, we propose a novel approach to detect and track eyes using geometric surface features on topographic manifold of eye images. First, in the joint spatial-intensity domain, a facial image is treated as a 3D terrain surface or image topographic manifold. In particular, eye regions exhibit certain intrinsic geometric traits on this topographic manifold, namely, the
pit
-labeled center and
hillside
-like surround regions. Applying a terrain classification procedure on the topographic manifold of facial images, each location of the manifold can be labeled to generate a terrain map. We use the distribution of terrain labels to represent the eye terrain pattern. The Bhattacharyya affinity is employed to measure the distribution similarity between two topographic manifolds. Based on the Bhattacharyya kernel, a support vector machine is applied for selecting proper eye pairs from the pit-labeled candidates. Second, given detected eyes on the first frame of a video sequence, a mutual-information-based fitting function is defined to describe the similarity between two terrain surfaces of neighboring frames. By optimizing the fitting function, eye locations are updated for subsequent frames. The distinction of the proposed approach lies in that both eye detection and eye tracking are performed on the derived topographic manifold, rather than on an original-intensity image domain. The robustness of the approach is demonstrated under various imaging conditions and with different facial appearances, using both static images and video sequences without background constraints.
Towards efficient context-specific video coding based on gaze-tracking analysis
Authors: Agrafiotis D. , Davies S. J. C. , Canagarajah N. , Bull D. R.
Published: January 2008

This article discusses a framework for model-based, context-dependent video coding based on exploitation of characteristics of the human visual system. The system utilizes variable-quality coding based on priority maps which are created using mostly context-dependent rules. The technique is demonstrated through two case studies of specific video context, namely open signed content and football sequences. Eye-tracking analysis is employed for identifying the characteristics of each context, which are subsequently exploited for coding purposes, either directly or through a gaze prediction model. The framework is shown to achieve a considerable improvement in coding efficiency.
Detecting eye fixations by projection clustering
Authors: Urruty Thierry , Lew Stanislas , Ihadaddene Nacim , Simovici Dan A.
Published: January 2008

Eye movements are certainly the most natural and repetitive movement of a human being. The most mundane activity, such as watching television or reading a newspaper, involves this automatic activity which consists of shifting our gaze from one point to another.

Identification of the components of eye movements (fixations and saccades) is an essential part in the analysis of visual behavior because these types of movements provide the basic elements used by further investigations of human vision.

However, many of the algorithms that detect fixations present a number of problems. In this article, we present a new fixation identification technique that is based on clustering of eye positions, using projections and projection aggregation applied to static pictures. We also present a new method that computes dispersion of eye fixations in videos considering a multiuser environment.

To demonstrate the performance and usefulness of our approach we discuss our experimental work with two different applications: on fixed image and video.
An empirical study of slice-based cohesion and coupling metrics
Authors: Meyers Timothy M. , Binkley David
Published: January 2008

Software reengineering is a costly endeavor, due in part to the ambiguity of where to focus reengineering effort. Coupling and Cohesion metrics, particularly quantitative cohesion metrics, have the potential to aid in this identification and to measure progress. The most extensive work on such metrics is with slice-based cohesion metrics. While their use of semantic dependence information should make them an excellent choice for cohesion measurement, their wide spread use has been impeded in part by a lack of empirical study.

Recent advances in software tools make, for the first time, a large-scale empirical study of slice-based cohesion and coupling metrics possible. Four results from such a study are presented. First, “head-to-head” qualitative and quantitative comparisons of the metrics identify which metrics provide similar views of a program and which provide unique views of a program. This study includes statistical analysis showing that slice-based metrics are not proxies for simple size-based metrics such as lines of code. Second, two longitudinal studies show that slice-based metrics quantify the deterioration of a program as it ages. This serves to validate the metrics: the metrics quantify the degradation that exists during development; turning this around, the metrics can be used to measure the progress of a reengineering effort. Third, baseline values for slice-based metrics are provided. These values act as targets for reengineering efforts with modules having values outside the expected range being the most in need of attention. Finally, slice-based coupling is correlated and compared with slice-based cohesion.
Identifying Crosscutting Concerns Using Fan-In Analysis
Authors: Marin Marius , Deursen Arie Van , Moonen Leon
Published: January 2008

Aspect mining is a reverse engineering process that aims at finding crosscutting concerns in existing systems. This article proposes an aspect mining approach based on determining methods that are called from many different places, and hence have a high
fan-in
, which can be seen as a symptom of crosscutting functionality. The approach is semiautomatic, and consists of three steps: metric calculation, method filtering, and call site analysis. Carrying out these steps is an interactive process supported by an Eclipse plug-in called FINT. Fan-in analysis has been applied to three open source Java systems, totaling around 200,000 lines of code. The most interesting concerns identified are discussed in detail, which includes several concerns not previously discussed in the aspect-oriented literature. The results show that a significant number of crosscutting concerns can be recognized using fan-in analysis, and each of the three steps can be supported by tools.
Efficient Analysis of DynAlloy Specifications
Authors: Frias Marcelo F. , Lopez Pombo Carlos G. , Galeotti Juan P. , Aguirre Nazareno M.
Published: January 2008

DynAlloy is an extension of Alloy to support the definition of actions and the specification of assertions regarding execution traces. In this article we show how we can extend the Alloy tool so that DynAlloy specifications can be automatically analyzed in an efficient way. We also demonstrate that DynAlloy's semantics allows for a sound technique that we call
program atomization
, which improves the analyzability of properties regarding execution traces by considering certain programs as atomic steps in a trace.

We present the foundations, case studies, and empirical results indicating that the analysis of DynAlloy specifications can be performed efficiently.
A real-time Java virtual machine with applications in avionics
Authors: Armbruster Austin , Baker Jason , Cunei Antonio , Flack Chapman , Holmes David , Pizlo Filip , Pla Edward , Prochazka Marek , Vitek Jan
Published: January 2008

This paper reports on our experience with the implementation of the Real-time Specification for Java on the Ovm open source Java virtual machine. We describe the architecture and main design decisions involved in implementing real-time Java on Ovm. We present the first use of Real-time Java in avionics in the context of control software for a ScanEagle Unmanned Aerial Vehicle.
Uniprocessor scheduling under precedence constraints for embedded systems design
Authors: Mangeruca Leonardo , Baleani Massimo , Ferrari Alberto , Sangiovanni-Vincentelli Alberto
Published: January 2008

In this paper, we present a novel approach to the constrained scheduling problem, while addressing a more general class of constraints that arise from the timing requirements on real-time embedded controllers. We provide general necessary and sufficient conditions for scheduling under precedence constraints and derive sufficient conditions for two well-known scheduling policies. We define mathematical problems that provide optimum priority and deadline assignments, while ensuring both precedence constraints and system's schedulability. We show how these problems can be relaxed to corresponding integer linear programming (ILP) formulations leveraging on available solvers. The results are demonstrated on a real design case.
Interactive schedulability analysis
Authors: Bordoloi Unmesh D. , Chakraborty Samarjit
Published: January 2008

A typical design process for real-time embedded systems involves choosing the values of certain system parameters and performing a schedulability analysis to determine whether all deadline constraints can be satisfied. If such an analysis returns a negative answer, then some of the parameters are modified and the analysis is invoked once again. This iteration is repeated until a schedulable design is obtained. However, the schedulability analysis problem for most task models is intractable (usually co-NP hard) and, hence, such an iterative design process is often very expensive. To get around this problem, we introduce the concept of “interactive” schedulability analysis. It is based on the observation that if only a small number of system parameters are changed, then it is not necessary to rerun the full schedulability analysis algorithm, thereby making the iterative design process considerably faster. We refer to this analysis as being “interactive” because it is supposed to be run in an interactive mode. This concept is fairly general and can be applied to a wide variety of task models. In this paper, we have chosen the recurring real-time task model, because it can be used to represent realistic applications from the embedded systems domain (containing conditional branches and fine-grained deadline constraints). Our experimental results show that using our scheme can lead to more than 20× speedup for each invocation of the schedulability analysis algorithm, compared to the case where the full algorithm is run.
SIGIR's 30th anniversary
Authors: Hiemstra Djoerd , Hauff Claudia , de Jong Franciska , Kraaij Wessel
Published: January 2008

This paper presents an analysis of all SIGIR proceedings to date in order to summarize what IR researchers discussed over the years, where they are from, and whether subcommunities can be identified, determined by co-authorship.
The CSIRO enterprise search test collection
Authors: Bailey Peter , Craswell Nick , Soboroff Ian , de Vries Arjen P.
Published: January 2008

This article describes a new TREC Enterprise Track search test collection -- CERC. The collection is designed to represent some real-world search activity within the enterprise, using as a specific example the Commonwealth Scientific and Industrial Research Organisation (CSIRO). It has a deep crawl of CSIRO's public-facing information, that is very similar to the crawl of a real-world search service provided by CSIRO. The search tasks are based on the activities of CSIRO Science Communicators, who are CSIRO employees that deal with public-facing information. Topics and judgments are tied to the Science Communicators in various ways, for example by involving them in the topic development process. The overall approach is to enhance the validity of the test collection as a model of enterprise search, by tying it to real-world examples.
Learning to rank for information retrieval (LR4IR 2007)
Authors: Joachims Thorsten , Li Hang , Liu Tie-Yan , Zhai ChengXiang
Published: January 2008

The task of "learning to rank" has emerged as an active and growing area of research both in information retrieval and machine learning. The goal is to design and apply methods to automatically learn a function from training data, such that the function can sort objects (e.g., documents) according to their degrees of relevance, preference, or importance as defined in a specific application.
Workshop on large-scale distributed systems for information retrieval
Authors: Junqueira Flavio P. , Plachouras Vassilis , Silvestri Fabrizio , Podnar Ivana
Published: January 2008

The Workshop on Large-Scale Distributed Systems for Information Retrieval was a venue for seminal ideas on the design of systems for search. The workshop focused mainly on mechanisms for P2P IR, which is currently a highly popular research area, but it also had fruitful discussions and presentations on other architectures for large-scale systems. Given the attendance and the good level of discussion, we conclude that systems for information retrieval is a growing and promising area of research.
7
th
Dutch-Belgian Information Retrieval Workshop March 28--29, 2007 Katholieke Universiteit Leuven, Belgium
Authors: Moens Marie-Francine , Tuytelaars Tinne , de Vries Arjen
Published: January 2008

The 7
th
Dutch-Belgian Information Retrieval Workshop on March 28 and 29, 2007 was hosted at the Katholieke Universiteit Leuven, Belgium. The DIR workshop was held for the second time at this university. Compared to its 2002 edition at the Katholieke Universiteit Leuven the DIR workshop has gained in importance over the years and is now run in a two-day format. During the two days of DIR 2007 we have welcomed 94 participants.
Aspects of sentence retrieval
Authors: Murdock Vanessa
Published: January 2008

Sentence Retrieval is the task of retrieving a relevant sentence in response to a query, a question, or a reference sentence. Tasks such as question answering, summarization, novelty detection, and information provenance make use of a sentence-retrieval module as a preprocessing step. The performance of these systems is dependent on the quality of the sentence-retrieval module. Other tasks such as information extraction and machine translation operate on sentences, either using them as training data, or as the unit of input or output (or both), and may benefit from sentence retrieval to build a training corpus, or as a post-processing step.
Ant colony optimization for real-world vehicle routing problems
Authors: Coltorti Dario , Rizzoli Andrea E.
Published: January 2008

Metaheuristics like ant colony optimization (ACO) can be used to solve combinatorial optimization problems. In this paper we refer to its successful application to the vehicle routing problem (VRP). At the beginning, we introduce the VRP and some of its variants. The variants of VRP were designed to reproduce the kind of situations faced in the real-world. Further, we introduce the fundamentals of ant colony optimization, and we present in few words its application to the solution of the VRP. At the end, we discuss the applications of ACO to a number of real-world problems: a VRP with time windows for a major supermarket chain in Switzerland; a VRP with pickup and delivery for a leading distribution company in Italy and an on-line VRP in the city of Lugano, Switzerland, where clients' orders arrive during the delivery process.
Lost gems of EC
Authors: Lobo Fernando G.
Published: January 2008

This summer I found a beautiful paper titled
The Equilibrium Genetic Algorithm and the Role of Crossover
[1]. It's from Nov/1993 and is authored by Ari Juels, Shumeet Baluja, and Alistair Sinclair. To my best knowledge, this paper describes the first evolutionary algorithm that explicitly replaces the population by a probability vector. While reading the paper, one can recognize that the main goal of the authors is to come up with an abstraction of the basic genetic algorithm in order to better analyze it from a mathematical perspective. To that end, they develop the
Equilibrium Genetic Algorithm
(EGA), and, as a byproduct, are able to show that some of the mechanisms present in standard genetic algorithms are likely to be, in certain cases, unnecessarily complex.
Foreword
Authors: Squillante Mark S.
Published: January 2008

The complexity of computer systems, networks and applications, as well as the advancements in computer technology, continue to grow at a rapid pace. Mathematical analysis, modeling and optimization have been playing, and continue to play, an important role in research studies to investigate fundamental issues and tradeoffs at the core of performance problems in the design and implementation of complex computer systems, networks and applications.
Fair bandwidth sharing under flow arrivals/departures
Authors: Marbukh Vladimir
Published: January 2008

A flow-level Markov model for fair bandwidth sharing with packet retransmissions and random flow arrivals/departures is proposed. The model accounts for retransmissions by assuming that file transfer rates are determined by the end-to-end goodputs rather than the corresponding throughputs as in the conventional model. The model predicts the network instability even under light exogenous load. Despite instability, a desirable metastable network state with finite number of flows in progress may exist. The network can be stabilized in a close neighborhood of the metastable state with admission control at the cost of small flow rejection probability.
Accuracy of measured throughputs and mean response times
Authors: Osogami Takayuki
Published: January 2008

The performance of computer systems such as Web systems is measured to guarantee quality of service (QoS) or to compare difference configurations of the systems [8]. We consider the problem of whether we should measure mean response time or throughput to better guarantee QoS or to better compare different configurations of a Web system. Specifically, is measured mean response time or measured throughput more accurate, when the Web system is measured for a fixed period of time?
Modeling of an online TV recording service
Authors: Hoßfeld Tobias , Leibnitz Kenji , Remiche Marie-Ange
Published: January 2008

Recently, new services have emerged which utilize the Internet as a delivery mechanism for multimedia content. With the advent of broadband accesses, more users are willing to download large volume content from servers, such as video files of TV shows. While some popular video services (e.g. YouTube.com) or some broadcasting companies (e.g. ABC.com) use streaming data with Flash technology, some media distributors (e.g. iTunes) offer entire TV shows for download. In this study, we investigate the performance of the German site OnlineTVRecorder.com (OTR), which acts as an online video cassette recorder (VCR) where users can program their favorite shows over a web interface and download the recorded files from a server or its mirrors. These files are offered in different file formats and can consist of several hundred megabytes up to 1 GB or more depending on the length of the TV show as well as the encoding format. OTR can, thus, be seen as an example for a server-based content distribution system with large data files.
Exponential supermartingales for evaluating end-to-end backlog bounds
Authors: Ciucu Florin
Published: January 2008

A common problem arising in network performance analysis with the stochastic network calculus is the evaluation of (min, +) convolutions. This paper presents a method to solve this problem by applying a maximal inequality to a suitable constructed supermartingale. For a network with D/M input, end-to-end backlog bounds obtained with this method improve existing results at low utilizations. For the same network, it is shown that at utilizations smaller than a certain threshold, fluid-flow models may lead to inaccurate approximations of packetized models.
Insensitivity for PS server farms with JSQ routing
Authors: Gupta Varun , Sigman Karl , Harchol-Balter Mor , Whitt Ward
Published: January 2008

Join-the-Shortest-Queue (JSQ) is a very old and popular routing policy for server farms. Figure 1 shows two examples of server farm architectures employing JSQ routing. In both cases, each incoming job is immediately dispatched, via a front-end router, to the queue with the fewest number of jobs, designated as the
shortest queue
(ties are broken at random). In Figure 1(a), jobs at a queue are served in First-Come-First-Served (FCFS) order. In Figure 1(b), jobs within a queue are served according to Processor-Sharing (PS), meaning that when there are
n
jobs at a queue, they
share
the processing capacity, each simultaneously receiving 1/nth of the service. We refer to Figure 1(a) as a JSQ/FCFS server farm and to Figure 1(b) as a JSQ/PS farm. If more detail is needed, we use the notation: M/G/K/JSQ/PS, denoting a Poisson arrival process, i.i.d. job sizes from a general distribution,
K
servers, JSQ routing; and PS scheduling at queues.
Approximate analysis of a network of fluid queues
Authors: Field Tony , Harrison Peter
Published: January 2008

Fluid models have for some time been used to approximate stochastic networks with discrete state. These range from traditional 'heavy traffic' approximations to the recent advances in bio-chemical system models. Here we use an approximate compositional method to analyse a simple feedforward network of fluid queues which comprises both probabilistic branching and superposition. This extends our earlier work that showed the approximation to yield excellent results for a linear chain of fluid queues. The results are compared with those from a simulation model of the same system. The compositional approach is shown to yield good approximations, deteriorating for nodes with high load when there is correlation between their immediate inputs. This correlation arises when a common set of external sources feeds more than one queue, directly or indirectly.
Product form stationary distributions for diffusion approximations to a flow-level model operating under a proportional fair sharing policy
Authors: Kang W. N. , Kelly F. P. , Lee N. H. , Williams R. J.
Published: January 2008

We consider a flow-level model of Internet congestion control introduced by Massoulié and Roberts [2]. We assume that bandwidth is shared amongst elastic documents according to a weighted proportional fair bandwidth sharing policy. With Poisson arrivals and exponentially distributed document sizes, we focus on the heavy traffic regime in which the average load placed on each resource is approximately equal to its capacity. In [1], under a mild local traffic condition, we establish a diffusion approximation for the workload process (and hence for the flow count process) in this model. We first recall that result in this paper. We then state results showing that when all of the weights are equal (proportional fair sharing) the diffusion has a product form invariant distribution with a strikingly simple interpretation in terms of dual random variables, one for each of the resources of the network. This result can be extended to the case where document sizes are distributed as finite mixtures of exponentials, and to models that include multi-path routing (these extensions are not described here, but can be found in [1]).
Rationale for co-arrays in Fortran 2008
Authors: Donev Aleksandar
Published: January 2008

This paper explains some of the technical decisions made during the incorporation of co-arrays in Fortran 2008. Familiarity with John Reid's summary of co-arrays [R07] is assumed. This document is by no means exhaustive: It is a selection of issues from my recollection. This article is not an official document and has not been approved by J3 or WG5. Many thanks to John Reid and Bill Long for helping me write this Rationale.
AFIS data compression
Authors: Zirkind Givon
Published: January 2008

This article describes the development and implementation of a data compression algorithm designed specifically for fingerprints, referred to as GBP compression. The algorithm is herein discussed. Data Compression algorithms can be designed for general applications, meaning the input data is unknown. This is more commonly referred to as generic data. [LI01] Or, data compression algorithms can be designed for specific applications. E.g. AFIS [Automated Fingerprint Identification Systems] "When the input is known, higher compression ratios can be achieved with the knowledge of the input data stream." To-date, the highest compression ratio for an unknown input data stream, for all data compression algorithms, is JPEG with an average compression ratio range of 1:17 --- 1:23. [PEN03] The algorithm herein discussed, has a compression ratio range of 1:68 --- 1:92. There is a value, time and place for each design method --- generic or specific --- depending upon a variety of factors. Due to the nature of the use of AFIS for law enforcement and incrimination as well as criminal conviction, there are social issues that make data integrity of paramount concern. This factor influences algorithm selection and design. A lossless algorithm is a must! Also, the nature of AFIS is such that it operates across borders and between states, municipalities and jurisdictions. In addition to the usual issues and resistance to accepting new technology, including software [e.g. resistance to change, fear of system failure, etc.], there are the issues of changing engineering standards [hardware and software] which are governmentally determined as well as governmental policy decisions. Likewise, the portability required in implementing a new algorithm, will have to deal with a variety of hardware and software; as well as be designed to integrate into existing systems. This integration must include the ability to incorporate existing JPEG data files, from existing police databases. This requires a handshaking of standards and conversion programs that maintain data integrity. In addition, there is an in depth discussion of the limits of compression with a novel perspective.
SIGGRAPHICON
Authors: Eisenberg Sharon
Published: January 2008

What is SIGGRAPHICON? It's the term I've coined for the rare phenomenon that occurs when both the SIGGRAPH convention and Comi-Con occur consecutive weekends at the San Diego Convention Center.
The little things
Authors: Teo Trina
Published: January 2008

A First timer's Memoir of SIGGRAPH 2007
SIGGRAPH Asia
Authors: Westman Hans
Published: January 2008

Asia is rising. While Japan has been dominant economically for decades, China and India are growing at a phenomenal rate, and the four Asian tigers, Hong Kong, Korea, Singapore and Taiwan are still strongly on the prowl. Asian governments are pumping billions of dollars into digital media technology research and development, and Asian contributions in this field have increased tremendously. SIGGRAPH conference figures show that while the number of papers from Asia has more than doubled in the new millennium, Asian attendance at the conference has fallen by about a third, due partly to cost and visa problems.
A Conversation with Mary Lou Jepsen
Authors: Stanik John
Published: January 2008

From Tunisia to Taiwan, Mary Lou Jepsen has circled the globe in her role as CTO of the OLPC (One Laptop Per Child) project. Founded by MIT Media Lab co-founder Nicholas Negroponte in 2005, OLPC builds inexpensive laptops designed for educating children in developing nations. Marvels of engineering, the machines have been designed to withstand some of the harshest climates and most power-starved regions on the planet. To accomplish this, Jepsen and her team had to reinvent what a laptop could be. As Jepsen says, “You ask different questions and you get different answers.” The resulting machine, named the XO, is uniquely adapted to its purpose, combining super-low-power electronics, mesh networking, and a sunlight-readable screen, which Jepsen designed herself. Although still shy of the “$100 laptop” goal envisioned in the beginning, the XO is still the most inexpensive laptop ever built.
Review of "Practical Subversion, Second Edition, by Daniel Berlin and Garrett Rooney," Apress, 2006, $34.99, ISBN: 1590597532
Authors: Gibian Marc S.
Published: January 2008

Review of "Practical Subversion, Second Edition, by Daniel Berlin and Garrett Rooney," Apress, 2006, $34.99, ISBN: 1590597532
Diffusivity Measurement of LiPF6, LiTFSI, LiBF4 in PC
Authors: Nishida Tetsuo , Nishikawa Kei , Fukunaka Yasuhiro
Published: January 2008

The molecular diffusion coefficients of LiPF6, LiTFSI and LiBF4 in PC were measured by Moiré pattern technique within the salt concentration range from 0.5 M to 1.0 M and at the temperature range from 258 K to 298 K. The diffusion coefficient of LiPF6 and LiTFSI are around 4×10-6 cm2 s-1 and that of LiBF4 is around 3×10-6 cm2 s-1 at 298 K. The activation energy of LiPF6- PC, LiTFSI-PC and LiBF4-PC system was calculated from an Arrhenius plots. They were 14, 18 and 21 kJ mol-1, respectively.
Study of Oxidation on Metallic Surfaces Using AC Electrochemical Impedance Spectroscopy
Authors: Hu Jianxun , Seitz Martin
Published: January 2008

Under a lubricating fluid medium, the kinetics of tin oxidation process has been investigated using electrochemical impedance spectroscopy. A two-probe configuration was applied, and the charge transfer was found to be dependent on the surface oxidation status. It was found that the charge transfer through the metal surface, resulting in a faradic reaction at the lubricating fluid/metal interface, is strongly influenced by the surface defect concentration from the oxidation. Therefore, a sensing technology can be developed to monitor the process and the degree of oxidation of the metallic substrate.
Treatment of Orange II Azo Dye Using Electrochemical and Photo-Oxidative Methods
Authors: Gomes Jewel A. , Cocke David L. , Mahmud Md A. , Moreno Hector , Peterson Eric , Mollah Mohammad Y. , Parga Jose R.
Published: January 2008

The ready availability and cheapness of azo compounds have increased their use as intermediary products in organic synthesis. In addition, they are widely applied in dye and pharmaceutical industries. However, they have been found to be toxic and in some cases mutagenic. Due to the large degree of aromatics present in azo dye molecules and their biological persistence, conventional biological and physical methods are ineffective for their discoloration, degradation, or removal. Electrochemical methods, such as electrocoagulation (EC), have been used in recent times for the most effective removal of orange II azo dye from wastewaters using iron, aluminum and combination of them as electrodes. Photo-oxidative methods might be another option for the photo-degradation of azo dyes. In this paper, we present our results on EC and photo-oxidative treatment of orange II azo dye. A cyclic voltammetric study on it was performed followed by a discussion on mechanisms of these processes.
Effect of Surface-Exchange Catalyst on the Transport Properties of MIEC Membrane for Hydrogen Separation
Authors: Hong Jialing , Wang Haibing , Gopalan Srikanth , Pal Uday
Published: January 2008

Gd0.2Ce0.8O1.9(GDC)-Gd0.08Sr0.88Ti0.95Al0.05O3{plus minus}δ(GSTA) is a mixed oxygen ionic and electronic conducting composite developed for hydrogen separation. By removing oxygen from steam using the membrane at elevated temperature, a H2-rich steam-hydrogen mixture was obtained. Generally, a permeation process is controlled by surface exchange reactions as well as bulk diffusion process of charged species. However, when the membrane thickness is less than a critical thickness, the permeation flux cannot be increased significantly by further decreasing the thickness of the membrane since the permeation process is surface reaction controlled. In order to improve the surface exchange reaction and thereby increase the permeation flux from the membrane, a NiO/GDC surface catalyst was applied onto the surface of GDC-GSTA bare sample. The effect of surface catalyst on transport properties of the MIEC membrane was investigated using electrical conductivity relaxation (ECR) method and hydrogen generation experiments.
Development of Reversible SOFC's for Hydrogen Production
Authors: Hawkes Grant L. , Sohal M. , Torgerson Paul , Armstrong T. , Williams Mark C.
Published: January 2008

The solid oxide fuel cell (SOFC) can be designed for both power generation (fuel cell) and hydrogen production (solid oxide electrolyser cell (SOEC)). In a reversible SOFC both functions are done in the same cell. One possible design suitable for this purpose is the metal-supported tubular SOFC (MTSOFC) under development at Worldwide Energy, Inc. (WE) in cooperation with Oak Ridge National Laboratory (ORNL). The feasibility of using the SOFC standard materials set for a reversible SOFC is being experimentally investigated at ORNL and modeled at Idaho National Laboratory (INL). Fluent Computational Fluid Dynamics (CFD) modeling of the SOEC has been initiated. This is the first known attempt to model a MTSOFC design. Results to-date indicate that parameters such as permeability of the porous metal support tube and steam concentration are important for both fuel cell and electrolyser mode. Current distribution is also a critical design co nsideration.
BaCe1-x-yZrxYyO3-d Protonic Conductor for Intermediate Temperature Solid Oxide Fuel Cells (IT-SOFCs)
Authors: Fabbri Emiliana , D'Epifanio Alessandra , Di Bartolomeo Elisabetta , Licoccia Silvia , Traversa E.
Published: January 2008

Proton conductors BaCe1-x-yZrxYyO3-a were synthesized by a wet chemistry process to obtain powders with controlled compositional homogeneity and purity at low processing temperatures. The synthesized powders were calcined at different temperatures, depending on Zr-content (x). To investigate the chemical stability, the calcined powders were exposed to CO2 and the phase analysis was performed by X-Ray Diffraction (XRD). Dense electrolytes were obtained pressing the calcined powders into cylindrical pellets and then sintering in the temperature range 1500-1600{degree sign}C, depending on Zr- content. Electrical conductivity of the sintered pellets was measured as a function of temperature and Zr-content by Electrochemical Impedance Spectroscopy (EIS).
Low Temperature Ethanol Steam Reforming in a Pd-Ag Membrane Reformer
Authors: Santucci Alessia , Borgogni Fabio , Cordiner Stefano , Traversa E. , Tosti Silvano
Published: January 2008

Ethanol steam reforming was been carried out in a membrane reactor consisting of a dense Pd-Ag thin wall tube, selectively permeable to the hydrogen, and a catalytic bed. In this way the hydrogen produced during the reaction was continuously removed from the reaction site. The permeator tube was produced via new technique of cold-rolling and diffusion welding. The experimental tests were performed in the temperature range of 400-450 {degree sign}C to study the performance of the membrane reactor in terms of reaction conversion and hydrogen yields. The main investigated operating parameters were the water/ethanol feed molar ratio, the pressure inside the membrane, the sweep gas mode, the spatial velocity and the kind of catalyst bed. In all tests, ultra pure hydrogen was separated through the membrane. The experimental results demonstrated the capability of the Pd-Ag membrane to shift the conversion of the ethanol steam reforming reaction bey ond the thermodynamic equilibrium.
Direct Water Splitting Under Visible Light with a Nanostructured Photoanode and GaInP2 Photocathode
Authors: Wang Heli , Deutsch Todd , Turner John A. A.
Published: January 2008

Thin films of hematite nanorod and GaInP2 were used for direct water splitting under visible light. In open circuit conditions, the potential of hematite shifted cathodically and that of GaInP2 anodically, which generated an open circuit voltage between the two electrodes. In short circuit condition, the combination of the two photoelectrodes can split water under visible light illumination, though with a very low current of µA/cm2 level even at 1 W/cm2 light. By means of chopped light, we found that hematite nanorod has a low photocurrent, which is responsible for the low short circuit current of the 2-electrode combination. The low photoresponse of hematite nanorods is due to the recombination of photo- generated charges, low holes mobility, and short diffusion length.
Developing a Battery using Concrete as an Electrolyte
Authors: Burstein Gordon T. , Speckert Erek I.
Published: January 2008

This paper presents a brief account of a developing electrochemical power source which uses set concrete (in this case, set cement paste containing no aggregate) as electrolyte. The system is designed with an aluminium anode which dissolves during discharge, and employs reduction of water to hydrogen on steel as cathode. The system functions as an alkaline aluminium/water cell, and can be operated at low current density.
Platinum-free Air Cathode Catalyst for Metal/Air Batteries
Authors: Sawai Keijiro , Maeda Yu-Suke
Published: January 2008

Platinum-free air cathode catalysts were prepared by heat- treating transition metal hexacyanometallate precursors dispersed on carbon black under an inert atmosphere. Oxygen reduction reaction on the prepared catalysts was examined with using gas-diffusion electrode floating on the surface of alkaline solution. Decomposition rate of peroxide generated during oxygen reduction on the catalyzed carbon electrode was estimated in-situ by monitoring the open circuit potential recovery after interrupting steady-state cathodic current applied to the air cathode. An effect of the peroxide elimination activity of the catalyst upon the polarization behavior of the air cathode was also described. From these results, a possibility of the cost-effective Pt-free air cathode catalysts for metal/air batteries is discussed.
Bamboo-carbon as a novel carbon-support/electrocatalyst of air cathodes
Authors: Lan Chi-Jui , Chi Yuean-Fa , Chin Tsung-Shune
Published: January 2008

A novel carbon-support/electrocatalyst, based on carbon derived from bamboo (the bamboo-carbon), is developed for use in air cathodes of metal-air batteries. Linear sweep voltametry, scanning electron microscopy and X-ray diffractometry were used to investigate the electrochemical performance, surface morphology and lattice structure, respectively, to optimize the performance of the air cathode. The activation layer made of powdered bamboo-carbon exhibited a current density approximately 280 mA/cm2 at -600 mVHg/HgO, the value was 24%, 99% and 117% larger than the current densities of those made of active carbon, carbon-black and XC-72, respectively. Blending equal amounts of bamboo-carbon and active carbon into the activation layer led to a lowered polarization by around 13% and a higher current density by about 8% over that obtained using bamboo-carbon alone. These results arise from the fact that bamboo-carbon has the largest surface are a, the well graphitized structure and a most suitable pore size distribution among the six carbon sources used in this study.
A Brief History of Non-Aqueous Metal-Air Batteries
Authors: Abraham K. M.
Published: January 2008

A new family of non-aqueous metal-air batteries has been discovered during the course of experiments carried out to study the Li intercalation behavior of graphite in a Li/C cell utilizing propylene carbonate containing gel-polymer electrolytes. Some of these batteries when fully developed could have practical specific energies of 1000-3000 Wh/kg. The Li/O2 battery is rechargeable and efforts should be made to fully develop it.
Polymer Electrolytes Based on Ionic Liquids and Their Application to Solid-state Thin-film Li-Oxygen Batteries
Authors: Ye Hui , Xu J. J.
Published: January 2008

Ionic liquids that are non-volatile, non-flammable, and stable with Li metal and exhibit wide electrochemical stability window are promising for application to lithium batteries, including Li/air cells. 1-Methyl-3-Propylpyrrolidinium bis (trifluoromethanesulfonyl)imide (P13TFSI) is identified to be such an ionic liquid. Dimensionally stable, elastic polymer electrolyte membranes with high thermal and electrochemical stability, high ionic conductivity and other desirable properties are synthesized by blending P13TFSI with lithium imide salt dissolved in it and the PVDF-HFP co-polymer. Preliminary solid-state, thin-film Li-oxygen cells are constructed using the polymer electrolyte membranes and their performance analyzed.
Lithium-Air Cells with High Capacity Cathodes
Authors: Dobley Arthur , Morein Christine , Roark Ralph
Published: January 2008

Lithium-air batteries consist of lithium anodes electrochemically coupled to atmospheric oxygen through an air cathode. Oxygen gas introduced into the battery through the air cathode is essentially an unlimited cathode reactant source. The theoretical specific energy of the Li-oxygen cell with 3 V is 5.4 kWh/kg, and that excluding oxygen is 11.5 kWh/kg, the highest for a metal air battery. Having previously developed a high capacity cathode for lithium-air cells, the current focus is on packaging the cell components, and testing the cells performance. Our improved air cathode structures have specific capacities approaching 4000 mAh/g of carbon. The specific capacities are over 250% greater than the highest specific capacities reported in literature. In this paper we briefly review the cathode design, discuss cell packaging, and report lithium-air cell performance data.
A Zinc-Air Fuel Cell
Authors: Smedley Stuart , Zhang Gregory X.
Published: January 2008

The Zinc Regenerative Fuel Cell (ZRFC) developed by the former Metallic Power Inc. from 1998 to 2004 is described. The component technologies and engineering solutions for various technical issues are discussed in relation to their functionality in the system. The system was designed to serve as a source of backup emergency power for remote or difficult to access cell phone towers during periods when the main power was interrupted. It contained a 12 cell stack developing 1.8 kW, a separate fuel tank containing zinc pellet fuel and electrolyte, and a zinc electrolyzer to regenerate the zinc pellets during standby periods. Offsite commissioning and testing of the system was successfully performed. The intellectual property of the ZRFC technology is now owned by Teck Cominco Metals Ltd.
Dual effect of Nai+ on Ca2+ influx through the Na+/Ca2+ exchanger in dialyzed squid axons. Experimental data confirming the validity of the squid axon kinetic model
Authors: Beaugé Luis , DiPolo Reinaldo
Published: January 2008

We propose a steady-state kinetic model for the squid Na+/Ca2+ exchanger that differs from other current models of regulation in that it takes into account, within a single kinetic scheme, all ionic [intracellular Ca2+ (Cai2+)-intracellular Na+ (Nai+)-intracellular Hi+] and metabolic (ATP) regulations of the exchanger in which the Cai2+-regulatory pathway plays the central role in regulation. Although the integrated ionic-metabolic model predicts all squid steady-state experimental data on exchange regulation, a critical test for the validity of it is the predicted dual effect of Nai+ on steady-state Ca2+ influx through the exchanger. To test this prediction, an improved technique for the estimation of isotope fluxes in squid axons was developed, which allows sequential measurements of ion influx and effluxes. With this method, we report here two novel observations of the squid axon Na+/Ca2+ exchanger. First, at intracellular pH (7.0) and in the absence of MgATP, Nai+ has a dual effect on Ca2+ influx: inhibition at low concentrations followed by stimulation at high Nai+ concentrations, reaching levels higher than those seen without Nai+. Second, in the presence of MgATP, the biphasic response to Nai+ disappears and is replaced by a sigmoid activation. Furthermore, the model predicts that Ca2+ efflux is monotonically inhibited by Nai+, more pronouncedly without than with MgATP. These results are predicted by the proposed kinetic model. Although not fully applicable to all exchangers, this scheme might provide some insights on expected net Ca2+ movements in other tissues under a variety of intracellular ionic and metabolic conditions.
IL-6 downregulates transcription of NTPDase2 via specific promoter elements
Authors: Yu Jin , Lavoie Élise G. , Sheung Nina , Tremblay Jacques J. , Sévigny Jean , Dranoff Jonathan A.
Published: January 2008

Bile ductular proliferation is markedly upregulated in biliary fibrosis and cirrhosis. However, the mechanisms regulating this upregulation in bile ductular proliferation have not been defined. Recently, we demonstrated that expression of the ectonucleotidase nucleoside triphosphate diphosphohydrolase-2 (NTPDase2/ Entpd2) by portal fibroblasts (PF) is a critical regulator of bile ductular proliferation. Since interleukin 6 (IL-6) is markedly upregulated in biliary cirrhosis, our aims were to determine the role and mechanism of IL-6 in the regulation of NTPDase2 by PF. We found that IL-6 downregulated NTPDase2 protein expression in a concentration-dependent and time-dependent fashion but did not alter PF α-smooth muscle actin expression. IL-6 markedly downregulated NTPDase2 mRNA expression. Expression of the IL-6 receptor gp130 but not the IL-6 receptor gp80 was detected in PF. Two transcription start sites were identified in rat Entpd2 by the method of RNA ligase-mediated rapid amplification of 5′ cDNA ends. The minimal promoter construct, but not shorter constructs, was downregulated by IL-6. Three putative IL-6 response elements were identified in silico and mutated. Mutation of all three response elements, but not fewer elements, completely abolished the IL-6 response. Thus IL-6 transcriptionally downregulates NTPDase2 expression by PF via actions at specific promoter elements independently of myofibroblastic differentiation. This effect may represent a novel signaling pathway by which bile ductular proliferation is dysregulated in biliary cirrhosis and thus provides a potential therapeutic approach for the regulation of bile ductular growth.