bluuebunny/crossref_metadata_2025 huggingface dataset:
Shrinking the hypervisor one subsystem at a time
Authors: Stecklina Julian
Published: October 2014

Efficient and secure networking between virtual machines is crucial in a time where a large share of the services on the Internet and in private datacenters run in virtual machines. To achieve this efficiency, virtualization solutions, such as Qemu/KVM, move toward a monolithic system architecture in which all performance critical functionality is implemented directly in the hypervisor in privileged mode. This is an attack surface in the hypervisor that can be used from compromised VMs to take over the virtual machine host and all VMs running on it.

We show that it is possible to implement an efficient network switch nfor virtual machines as an unprivileged userspace component running in the host system including the driver for the upstream network adapter. Our network switch relies on functionality already present in the KVM hypervisor and requires no changes to Linux, the host operating system, and the guest.

Our userspace implementation compares favorably to the existing in-kernel implementation with respect to throughput and latency. We reduced per-packet overhead by using a run-to-completion model an are able to outperform the unmodified system for VM-to-VM traffic by a large margin when packet rates are high.
String deduplication for Java-based middleware in virtualized environments
Authors: Horie Michihiro , Ogata Kazunori , Kawachiya Kiyokuni , Onodera Tamiya
Published: October 2014

To increase the memory efficiency in physical servers is a significant concern for increasing the number of virtual machines (VM) in them. When similar web application service runs in each guest VM, many string data with the same values are created in every guest VMs. These duplications of string data are redundant from the viewpoint of memory efficiency in the host OS. This paper proposes two approaches to reduce the duplication in Java string in a single Java VM (JVM) and across JVMs. The first approach is to share string objects cross JVMs by using a read-only memory-mapped file. The other approach is to selectively unify string objects created at runtime in the web applications. This paper evaluates our approach by using the Apache DayTrader and the DaCapo benchmark suite. Our prototype implementation chieved 7% to 12% reduction in the total size of the objects allocated over the lifetime of the programs. In addition, we observed the performance of DayTrader was maintained even under a situation of high density guest VMs in a KVM host machine.
Change detection in streaming data in the era of big data
Authors: Tran Dang-Hoan , Gaber Mohamed Medhat , Sattler Kai-Uwe
Published: October 2014

Big Data is identified by its three Vs, namely velocity, volume, and variety. The area of data stream processing has long dealt with the former two Vs velocity and volume. Over a decade of intensive research, the community has provided many important research discoveries in the area. The third V of Big Data has been the result of social media and the large unstructured data it generates. Streaming techniques have also been proposed recently addressing this emerging need. However, a hidden factor can represent an important fourth V, that is variability or change. Our world is changing rapidly, and accounting to variability is a crucial success factor. This paper provides a survey of change detection techniques as applied to streaming data. The review is timely with the rise of Big Data technologies, and the need to have this important aspect highlighted and its techniques categorized and detailed.
Contextual crowd intelligence
Authors: Ooi Beng Chin , Tan Kian Lee , Tran Quoc Trung , Yip James W.L. , Chen Gang , Ling Zheng Jye , Nguyen Thi , Tung Anthony K.H. , Zhang Meihui
Published: October 2014

Most data analytics applications are industry/domain specific, e.g., predicting patients at high risk of being admitted to intensive care unit in the healthcare sector or predicting malicious SMSs in the telecommunication sector. Existing solutions are based on "best practices", i.e., the systems' decisions are
knowledge-driven and/or data-driven
. However, there are rules and exceptional cases that can only be precisely formulated and identified by subject-matter experts (SMEs) who have accumulated many years of experience. This paper envisions a more intelligent database management system (DBMS) that captures such knowledge to effectively address the industry/domain specific applications. At the core, the system is a hybrid human-machine database engine where the machine interacts with the SMEs as part of a feedback loop to gather, infer, ascertain and enhance the database knowledge and processing. We discuss the challenges towards building such a system through examples in healthcare predictive analysis -- a popular area for big data analytics.
On power law distributions in large-scale taxonomies
Authors: Babbar Rohit , Metzig Cornelia , Partalas Ioannis , Gaussier Eric , Amini Massih-Reza
Published: October 2014

In many of the large-scale physical and social complex systems phenomena fat-tailed distributions occur, for which different generating mechanisms have been proposed. In this paper, we study models of generating power law distributions in the evolution of large-scale taxonomies such as Open Directory Project, which consist of websites assigned to one of tens of thousands of categories. The categories in such taxonomies are arranged in tree or DAG structured configurations having parent-child relations among them. We first quantitatively analyse the formation process of such taxonomies, which leads to power law distribution as the stationary distributions. In the context of designing classifiers for large-scale taxonomies, which automatically assign unseen documents to leaf-level categories, we highlight how the fat-tailed nature of these distributions can be leveraged to analytically study the space complexity of such classifiers. Empirical evaluation of the space complexity on publicly available datasets demonstrates the applicability of our approach.
Interview
Authors: Piatetsky Gregory
Published: October 2014

We discuss the most important database research advances, industry developments, role of relational and NoSQL databases, Computing Reality, Data Curation, Cloud Computing, Tamr and Jisto startups, what he learned as a chief Scientist of Verizon, Knowledge Discovery, Privacy Issues, and more.
Port Squatting
Authors: Neville-Neil George
Published: October 2014

Dear KV, A few years ago you upbraided some developers for not following the correct process when requesting a reserved network port from IETF (Internet Engineering Task Force). While I get that squatting a used port is poor practice, I wonder if you, yourself, have ever tried to get IETF to allocate a port. We recently went through this with a new protocol on an open-source project, and it was a nontrivial and frustrating exercise. While I wouldn’t encourage your readers to squat ports, I can see why they might just look for unallocated ports on their own and simply start using those, with the expectation that if their protocols proved popular, they would be granted the allocations later.
The Importance of Setting the Stage
Authors: Johnson Glenn , Rosenberger James L. , Chow Mosuk
Published: October 2014

The motivation for engaging in peer review of teaching vacillates between providing opportunities to improve teaching and evaluating teaching performance. We strive to find ways to maximize the benefits of peer review of teaching because this activity provides a valuable opportunity for peer collaboration and curricular coordination within a program. This article discusses a range of strategies that we have used to engage online instructors in thinking critically about the quality of their online instruction; we show how these strategies help "set the stage" for maximizing the benefits that a well structured peer review of online teaching can provide.
Oncolytic Poxviruses
Authors: Chan Winnie M. , McFadden Grant
Published: October 2014

Current standard treatments of cancer can prolong survival of many cancer patients but usually do not effectively cure the disease. Oncolytic virotherapy is an emerging therapeutic for the treatment of cancer that exploits replication-competent viruses to selectively infect and destroy cancerous cells while sparing normal cells and tissues. Clinical and/or preclinical studies on oncolytic viruses have revealed that the candidate viruses being tested in trials are remarkably safe and offer potential for treating many classes of currently incurable cancers. Among these candidates are vaccinia and myxoma viruses, which belong to the family Poxviridae and possess promising oncolytic features. This article describes poxviruses that are being developed for oncolytic virotherapy and summarizes the outcomes of both clinical and preclinical studies. Additionally, studies demonstrating superior efficacy when poxvirus oncolytic virotherapy is combined with conventional therapies are described.
Electrodeposition and Characterization of Manganese Dioxide Thin Films on Silicon Pillar Arrays for 3D Thin-Film Lithium-Ion Batteries
Authors: Zargouni Yafa , Deheryan Stella , Radisic Aleksandar , Cott Daire J. , Rochan Sinha , Alouani Khaled , Huyghebaert Cedric , Vereecken Philippe M.
Published: October 2014

In this paper, we evaluate PECVD carbon coating for TiN/Si substrate as a technologically relevant current collector for 3D thin film Lithium ion battery applications. Carbon coated TiN/silicon pillars (with aspect ratio of 30) served as substrate for electrolytic manganese dioxide (EMD) deposition from aqueous bath to be tested as positive electrode for Lithium ion batteries. Reversible insertion and extraction of Li+ is observed showing an improved cycle performance for carbon coated TiN substrates compared to Pt coated TiN substrates. The average lithium storage capacity for planar EMD films is about 50mAh/cm2 (at 10mV/s comparable with charging rate of 20 C). Based on a surface area gain of 28 for the 3D pillar structures, a capacity of 0.2mAh/cm2 is expected for conformal coated 200 nm film at these high rates.
A New Technique of Electro-Synthesis of Polypyrrole Nanoparticles
Authors: Basumallick Srijita
Published: October 2014

We report here a two phase electro-oxidation technique for the synthesis of polypyrrole from pyrrole using picric acid as dopant onto a stainless steel electrode. Pyrrole and its red color H-bonded complex with picric acid are almost insoluble in water but soluble in di-chloromethane (DCM). Water and DCM form an immiscible solvent pair. We demonstrated that polypyrrole nano particles are formed in aqueous phase onto working electrode coupled with Pt counter electrode placed near the boundary of organic phase by passing a current of 0.25 mA/cm2 for 600 s under galvanostatic condition. This has been explained in terms of steady but small concentration of pyrrole picric acid complex in the water phase and free radical scavenging property of picric acid.
Synthesis of Co-Deposited Electroless Pd-Cu Catalyst for Nitrate Reduction
Authors: Anderson Shannon , Kalu Egwu Eric , Onyeozili Edith N
Published: October 2014

Electrochemical and thermodynamic data obtained from the determination of the corrosion potentials of Cu and Pd in various reducing agents (formaldehyde, hypophosphite and ammonia borane) and their mixtures was used to formulate a stable electroless bath for co-deposition of Cu and Pd on Al2O3 substrate. The electrolessly deposited Pd-Cu catalyst was characterized using SEM, EDAX and BET measurements. The Pd-Cu catalyst on alumina was found to be active for nitrate reduction in aqueous solution. The activity and composition of the catalyst increased with electroless plating time up to 30 minutes whereupon the variation of metal composition was minimal. The BET measurement showed that the electroless plating decreases the BET surface area of the catalyst thereby suggesting a macroporous mechanism for nitrate reduction on electroless Pd-Cu catalyst. The supported electroless Pd-Cu catalyst converted most of the nitrate in solution into preferred nitrogen gas product rather than ammonia.
Analytical Modeling of PEM Fuel Cell Gas Diffusion Layers Deformation under Compression: Part 2 - Nonlinear Behaviour Region
Authors: Norouzifard Vahid , Bahrami Majid
Published: October 2014

In the Proton exchange membrane PEM fuel cell stack, the porous gas diffusion layer (GDL) provides mechanical support for the membrane assembly against the compressive loads imposed by bipolar plates. In this paper, using assumption of existing gap between the fibers in the GDL micro-structure, an analytical model proposed in first part of this study for linear region is extended to predict the GDL nonlinear mechanical behaviour in low compressive pressures. The present unit cell model covers salient microstructural parameters and properties of the fibrous porous medium including: carbon fiber diameter, elastic modulus, pore size distribution, gap size distribution between fibers. A comparison between the present model and the GDL stress-strain data shows that the assumption of closing gap between the fibers during compression can accurately describe the GDL nonlinear behaviour. The proposed model also provides useful information about the microstructural properties of the GDL during compression such as gap distribution between fibers that can be used in the GDL transport properties prediction.
Palladium Nanodendrites Deposited on Electrochemically Activated Carbon Based Support for Electrocatalytic Applications
Authors: Maniam Kranthi Kumar , Chetty Raghuram
Published: October 2014

This paper focuses on the morphological nature of Pd electrodeposited on different carbon supports such as Vulcan XC-72R (VCX), carbon nanotubes (CNTs) and wood apple shell carbon (WASC), and presents a comparative assessment of the catalytic activity on different supports towards formic acid (HCOOH) oxidation and oxygen reduction reaction (ORR) in low-temperature fuel cells. The carbon supports subjected to an electrochemical activation by potential cycling in an acidic media followed by deposition of Pd showed dendrite formation as confirmed by scanning electron micrographs irrespective of the morphology of carbon material. Pd dendrites on WASC showed the highest electrochemical surface area of 86.1 m2g-1 among the electrocatalysts studied. The carbon supported Pd dendrite showed the following order towards the activity of formic acid oxidation: WASC > VXC > CNTs, whereas for oxygen reduction reaction the activity was in the order CNTs > WASC > VXC. The results suggest the need for different carbon support for anode and cathode reaction of direct liquid fuel cells.
Identifying Water Thickness in Various Layers in PEMFCs through EIS and X-ray Radiography
Authors: Antonacci Patrick , Lee Jongmin , Yip Ronnie , Ge Nan , Tabuchi Yuichiro , Kotaka Toshikazu , Bazylak Aimy
Published: October 2014

In order to understand the detailed relationship between liquid water presence and polymer electrolyte membrane fuel cell (PEMFC) performance, diagnostic tools which offer an accurate measure of liquid water in the fuel cell during operation are required. This work presents electrochemical impedance spectroscopy (EIS) and synchrotron X-ray radiography for studying this liquid water/performance relationship. X-ray radiography was applied in the through-plane direction of the cell, and by using the Beer-Lambert law, liquid water was quantified in the anode and cathode flow channels, gas diffusion layers (GDLs), microporous layers (MPLs), and membrane electrode assembly (MEA). EIS was used as a non-invasive diagnostic tool in quantifying the equivalent resistances of the fuel cell. This paper presents studies of water thickness in various layers of the fuel cell during EIS measurements and demonstrates the role of the water thickness of each layer in the overall mass transport resistance of the fuel cell. The fuel cells analyzed have two varying MPL thicknesses at increasing constant current densities. Nyquist plots will be discussed with relation to amount of liquid water visualized.
A Cahn-Hilliard Modeling of Metal Oxide Thin Films for Advanced CMP Applications
Authors: Karagoz Ayse , Sengul Yasemin , Basim G. Bahar
Published: October 2014

Chemical mechanical planarization (CMP) process enables topographic selectivity through formation of a protective oxide thin film on the recessed locations of the deposited metal layer, while a continuous chemical oxidation reaction is followed by mechanical abrasion takes place on the protruding locations. This paper demonstrates a new approach to CMP process optimization in terms of analyzing the nano-scale surface topography of the protective metal oxide films and modeling their growth through a Cahn-Hilliard equation (CHE) approach as an alternative to classical nucleation theory. It is observed that the material removal rate mechanisms and the consequent planarization performance depend on the nature of nucleation of the metal oxide films, which is a function of the oxidizer concentration of the CMP slurry.
Current Status of Slurries and Cleans for CMP of III-V Device Fabrications – A Critical Review
Authors: Banerjee Gautam
Published: October 2014

With the growth of cloud computing market, the need for logic and memory chips for data centers have been steadily growing which require low power and high performance. Another area of growing semiconductor application is mobile products which require increasingly higher performance without sacrificing power. The above two requirements can only be achieved by scaling supply voltage (Vdd). III-V materials enable Vdd scaling to address power without sacrificing performance due to the very high electron injection velocity at virtual source compared to Si. For example, Vinj (InGaAs) > 2Vinj (Si) at less than half VDD. The development at Intel on InGaAs and at IMEC on Ge based FinFET structures have made it possible to conceive new integration schemes[1]. In order to enable such CMOS fabrication, development of CMP (Chemical Mechanical Planarization) slurry, post CMP clean and modification of the presently available process tools need to be done. While new slurries and cleans will be needed to planarize III-V film layer(s) without compromising the film composition (and functionality), modification of the process tool will be needed to address potential release of toxic waste water into the waste stream after planarization. In this paper, the status of development of CMP processes, slurries and post CMP cleans will be reviewed and the critical needs to enable for the future III-V device integration will be analyzed.
Dual-Function Coaxial Supercapacitor Cable
Authors: Yu Zenan , Moore Julian , Lorenzo Josie , Li Chao , Thomas Jayan
Published: October 2014

A dual-function coaxial supercapacitor cable, which has the capability to be used as an electrical cable and an energy storage device, is shown. The outer cover facilitates energy storage, while the core within is used for the passing of electricity. Not only is this new architecture pliable, but it also shows high flexibility and gives high energy and power densities. These properties, along with the astounding results of its usage, show that it has successfully married the functions of storing and sending electricity into one device.
PAN@AuPd@MnO2 Core-Shell Nanopillars for High-Performance Electrochemical Energy Storage
Authors: Yu Zenan , Moore Julian , Duong Binh , Li Chao , Thomas Jayan
Published: October 2014

A quick and easy method to print highly ordered nanopillar structures has been developed without the need of costly equipment or sacrificial templates. The resulting polymer architecture is used as a scaffold to deposit manganese dioxide as a pseudocapacitive active material. Cyclic voltammetry (CV) and galvanostatic charge/discharge (GCD) measurements were used to characterize electrode performance. This facile fabrication process along with superior power and energy density make this electrode design very appealing for future energy storage systems.
Indium Tin Oxide Photonic Crystal for Controllable Light Coupling in Solar Cells by an Inexpensive Soft Lithography with HD-DVD and Blu-ray
Authors: Chen Biyan , Mathai Cherian J. , Mukherjee Somik , Gangopadhyay Shubhra
Published: October 2014

We present an indium tin oxide/polymethylsilsesquioxane (ITO/PMSSQ) photonic crystal (PC) with grating structure. This topography exhibits multiple coupling resonances in specific regions of the solar spectrum, which can be controlled by tuning the angle and polarization of incident light as demonstrated through simulation and experimental results. The ITO/PMSSQ grating structures are prepared by simple soft lithography procedures using commercial HD-DVD and Blu-ray as template molds. The surface topography also includes geometrical singularities such as nanogaps and nanocones, which lead to further enhanced light trapping characteristics. Together, these singularity-embedded photonic crystal gratings result in concentrated electromagnetic fields at the aforementioned singularities, which could be especially helpful in separating the tightly bonded excitons in organic solar cells. Simulation shows an absorption enhancement over the full spectral range of ITO PCs-based solar cells with substantial increases closer to the band edge under s-polarized light.
A Carbon Paste Composite Electrode with Mixture of Zirconium Dioxide and Titanium Dioxide to Detect Heavy Metals Studied by SEM and XPS
Authors: Sullivan Mary , Spradlin Corrie , Nguyen Phuong Khanh Quoc , Lunsford Suzanne Kay
Published: October 2014

The purpose of this study is to show that an alternative and novel modified electrode such as the zirconium dioxide with titanium dioxide (ZrO2/TiO2) carbon paste electrode could be utilized in the area of highly toxic metal detection such as the highly toxic metal indium. The challenges of the development of an electrochemical sensor over the last two decades which possess the following qualities such as user friendly, robust, selective, low detection limits and allowing for fast analyses in toxic metal detection are the reasons for this investigation. A carbon modified electrode was developed with zirconium dioxide with titanium dioxide for the determination of indium (III) in the presence of lead (II) by Square Wave Anodic Stripping Voltammetry (SWASV). This novel carbon paste electrode zirconium dioxide with titanium dioxide was examined by scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) to understand the possible interaction between the determination of the sample and the modified electrode surface.
Dynamometer Testing of Planar Mixed-Potential Sensors
Authors: Kreller Cortney R. , Sekhar Praveen K. , Prikhodko Vitaly , Pihl Josh , Curran Scott , Parks James E , Mukundan Rangachary , Garzon Fernando , Brosha Eric L.
Published: October 2014

Mixed-potential sensors for vehicle on-board emissions monitoring applications have been fabricated in an automotive planar sensor configuration using high temperature ceramic co-fire methods. The sensing element consists of dense Pt and LaSrCrO electrodes and a porous 3 mol% YSZ electrolyte. This sensor construct exhibits preferential selectivity to NOx (NO+NO2) when operated at a positive current bias. The performance of the planar sensors under engine-out conditions was recently evaluated at the Oak Ridge National Laboratory National Transportation Research Center on a GM 1.9L CIDI diesel engine. The sensor response qualitatively tracked transients in NOx measured via FTIR under transient engine operation. Additionally, quantitative correlation between sensor voltage response and total NOx concentration was obtained under steady-state engine speed and load while varying exhaust gas recirculation (EGR) levels.
Surface Dependence of pH Sensors on AlGaN/GaN Heterostructure
Authors: Maeda Yutaro , Niigata Kazutaka , Narano Kazuhiro , Wang Lei , Ao Jin-Ping
Published: October 2014

A pH sensor on an AlGaN/GaN heterostructure with differentsurface conditions was developed and evaluated. The averagesensitivity is 49.5, 47.2 and 51.8 mV/pH, respectively, forsamples with i-GaN, p-GaN and n-GaN cap layers on the AlGaNsurface. The average sensitivity is 52.9, 53.5, 54.1, and 55.2mV/pH, respectively, for the samples with an AlGaN surface andAl composition of 22%, 24%, 25%, and 35%. The sensitivity ofthe pH sensor on AlGaN/GaN heterostructure increases if theAlGaN surface is adopted and increases with increasingaluminum composition.
The Consequence of Stress Intensity on Fatigue Crack Propagation in High-Strength Steels in Sour Environment
Authors: Ziomek-Moroz Margaret , Hawk Jeffrey A. , Collins Keith , Thodla Ramgopal , Gui Feng
Published: October 2014

The fatigue crack propagation behavior of high-strength carbon steel in 5% NaCl buffered with Na2CO3/ CO2 and in contact with 0.83 H2S at 20°C was studied using frequency scans and microscopic surface analyses. The solution pH was 7. A fatigue crack growth rate (FCGR) was measured as a function of frequency for stress intensity factors (ΔK) of 315.4 and 153.5 MPa√cm, respectively. The FCGR versus frequency plot showed a linear dependence with a gradient of -0.5 for of 315.4 MPa√cm, whereas at 153.5 MPa√cm linear dependence was not observed. Samples failed catastrophically after the cyclic stress testing in the autoclave for 315.4 and 153.5 MPa√cm. Microscopic investigations of the fracture surface for the higher ΔK revealed the presence of pits, secondary cracks and characteristics suggesting overall brittle fracture. The fractograph after cyclic testing at lower ΔK revealed areas characteristic of ductile fracture near the outer surfaces of the compact tension specimen and indications of brittle fracture in the central region away from the outer surfaces. The frequency scans and the microscopic investigations confirmed different failure mechanisms of the steel for 315.4 and 153.5 MPa√cm.
Corrosion in Construction Materials
Authors: Marquez Andres
Published: October 2014

Corrosion studies in different construction materials, such as Ibeams, reinforcing bars, angle bars, flat bars, made of several typesof steel alloys, and for other types of materials made of aluminum alloys, were carried out to evaluate their performance. Conditions such as acid type/concentration, Temperature, air or CO2 bubbling, inhibitor presence, among others were varied during the experiments to explore the sets of conditions and to identify not only the most corrosive environments, but the most resistant material. The findings are presented and discussed.
Electropolishing of Kovar Alloy for Vacuum Applications
Authors: Dündar Yasemin , Demirci Gökhan , Erdogan Metehan , Karakaya Ishak
Published: October 2014

Kovar (53% Fe – 29%Ni - 17% Co) is one of the most commonly used materials in high vacuum applications which quite often require electrical insulation(s). Kovar has thermal expansion coefficient close to that of alumina over the range from brazing to cryogenic temperatures. Therefore, joining problems due to difference in thermal expansion coefficients can be minimized when alumina and Kovar alloy are used together (1-4). Besides, Kovar parts should have smooth surfaces to minimize outgas from the surface due to inadequate cleaning, for the applications that require long vacuum life. This paper presents the electrochemical polishing of Kovar alloy in an electrolyte containing acetic acid, chromic acid and water. The primary objectives are to set a proper cell design and determine appropriate electropolishing conditions to attain the minimum surface roughness for Kovar parts in vacuum applications.
Enhancing the Rate of Organic Material Decomposition Photo Catalyzed by High Performance Visible Light Activated Tungsten Oxide
Authors: Fukushi Daisuke , Sato Akira , Kusaka Takao , Kataoka Yoshinori , Kobayashi Kumpei
Published: October 2014

We report a novel approach for increasing the rate of organic material decomposition photo-catalyzed by visible light activated tungsten oxide (WO3). It was confirmed that photo-catalysis by WO3 nano-particles fabricated by gas phase method and annealed at 600 °C for 1 hour achieves 30 times higher decomposition rate compared to photo-catalysis by commonly reported nitrogen doped titanium dioxides (TiO2). 1) The high decomposition rate in the presence of WO3 nano-particles could be attributed to their high crystalline quality and large surface area. It was also found that the decomposition rate can further be doubled by addition of metal oxides such as zirconium oxide (ZrO2) or TiO2. Furthermore, it is shown that immersing WO3 nano-particles mixed with ZrO2 or TiO2 in Pt colloid or Ru ionic solutions achieve complete decomposition of organic material to CO2 and H2O. These novel methods are already in the mass production stage.
Mitigation of PEM Fuel Cell Electrolyte Degradation with Metal Oxide/Nafion Nanofiber Interlayers
Authors: Zaton Marta , Jones Deborah , Rozière Jacques
Published: October 2014

A new nanofiber-network material enriched with cerium oxide nanoparticles (NFCeOx) has been developed as radical trap at the membrane electrode interface. Mitigation properties of NFCeOx, oriented to the anode side and to the cathode side, were investigated in in situ OCV hold test conditions at low relative humidity (50 %) and high temperature (90 °C). The results of OCV hold testing under these conditions show that whereas MEAs integrating non-modified Nafion®-212, show a marked drop in OCV with time, and end of life at < 200 hours, an MEA comprising a NFCeOx at the anode side gave very stable OCV and a lifetime close to 1000 hours. Post mortem analysis of aged MEAs indicated lower degree of degradation for a membrane protected by NFCeOx than for the reference material. These results are in agreement with OCV profile and fluoride emission rate.
Uranium Electrodeposition Using Direct Potential Technique in Less Acidic Aqueous Media
Authors: Saliba-Silva Adonis Marcelo , Oliveira Eneas Tavares de , Durazzo Michelangelo
Published: October 2014

Electrodeposition of uranium is a common practice to create samples for alpha spectrometry and it could be an alternative way to produce irradiation LEU targets to fabricate radiopharmaceuticals as 99Mo used for cancer diagnosis. Usually electrodeposition of uranium uses ionic or aqueous solutions to produce uranium deposits in less acidic electrolytes (pH>2.5). During uranium electrodeposition, there is a high competition with H2 evolution, once cathodic potentials are very high. In less acidic electrolyte the electrodeposition is uranyl hydroxyl and uranium oxides compounds, formed directly from uranyl (U-VI) structure. A reliable regression equation (R2=0.836) for alpha emission activity of uranium deposition was obtained, based on cell temperature and electrodeposition time. The deposition has oxide/hydroxide nature, acting as insulator during electrochemical process. The maximum level of deposited uranium, in terms of alpha activity, was around 34 Bq.cm-2 (-1.8 VAg/AgCl, 2000 s, 60°C). In this condition, the inferred maximum amount of uranium was ~5.4 mg [U] /cm2, which might be interesting to build probe samples to simulate irradiation targets.
Sandwich Biobattery with Enzymatic Cathode and Zinc Anode for Powering Sensors
Authors: Majdecka Dominika , Dramińska Sylwia , Stolarczyk Krzysztof , Kizling Michal , Krysiński Pawel , Golimowski Jerzy , Bilewicz Renata
Published: October 2014

Carbon paper covered with naphthylated multi-walled carbon nanotubes was used as the conducting support for the construction of a biocathode in a hybrid biofuel cell (biobattery). Laccase Cerrena unicolor enzyme was employed as the catalyst for the 4e reduction of oxygen and a zinc disc covered with hopeite was the anode. Carbon nanotubes increase the working surface area of the electrode and provide direct contact with the active sites of laccase. Biobattery parameters under externally applied resistance, and power-time dependencies under flow cell conditions were evaluated. The system including the sandwich biobattery connected to a simple sensor was employed for monitoring the neurotransmitter – catechol. The biobattery powered sensor gave oxidation currents linearly dependent on catechol in the range 0 – 2 mM and with a correlation coefficient of 0.998. We show that the zinc – air biobattery with laccase as the cathode catalyst can be integrated with analytical devices and power them even in long-time monitoring experiments.
ZnO Gate Based MOSFETs for Sensor Applications
Authors: Saikumar Ashwin Kumar , Skaria Giji , Sundaram Kalpathy B
Published: October 2014

A metal–oxide–semiconductor field-effect transistor (MOSFET) with transparent ZnO as its gate metal was fabricated and its photodetecting capabilities were investigated. For the fabrication of the MOSFET, a four level mask was used. The first level was used for making the diffusion wells for source and drain. The second level to form the via holes for Aluminum deposition followed by the third level to shape the source and drain contact structures. Finally the fourth level mask to pattern the ZnO gate metal. The ZnO gate metal was deposited by sputtering process. The electrical characteristic analysis was performed on the fabricated MOSFETs when different types of light were incident on it.
Nanostructured Electrodes Via Electrostatic Spray Deposition for Energy Storage System
Authors: Chen Chunhui , Agrawal Richa , Kim Tea Kwon , Li Xifei , Chen Wei , Yu Yan , Beidaghi Majid , Penmatsa Varun , Wang Chunlei
Published: October 2014

Energy storage systems such as Li-ion batteries and supercapacitors are extremely important in today’s society, and have been widely used as the energy and power sources for portable electronics, electrical vehicles and hybrid electrical vehicles. A lot of research has focused on improving their performance; however, many crucial challenges need to be addressed to obtain high performance electrode materials for further applications. Recently, the electrostatic spray deposition (ESD) technique has attracted great interest to satisfy the goals. Due to its many advantages, the ESD technique shows promising prospects compared to other conventional deposition techniques. In this paper, our recent research outcomes related to the ESD derived anodes for Li-ion batteries and other applications is summarized and discussed.
Characterization of Lithium Thin Film Batteries by Electrochemical Impedance Spectroscopy
Authors: Larfaillou Séverin , Guy-Bouyssou Delphine , Le Cras Frédéric , Franger Sylvain
Published: October 2014

In this study, lithium thin film batteries were characterized using Electrochemical Impedance Spectroscopy (EIS) to analyze the interfaces evolution during cycling and aging. Firstly, the conception of symmetrical Pt/LiPON/Pt blocking cells shows the resistive contribution of the solid electrolyte and let us access to the ionic transport parameters such as the ionic conductivity and the dielectric constant, respectively of 2.10-6 S.cm-1 and 20. Moreover, EIS performed on fresh and aged battery highlights an increase of LiPON/Lithium interface resistivity, which may be caused by a lithium metal degradation or oxidation at the interface. This observation was confirmed by a cycle inducing the creation of a fresh LiPON/Lithium interface and a decrease of the corresponding EIS response. Further works will focus on the understanding of the origin and the evolution of each contribution thanks to impedance characterization of half-cells.
Analysis of Impedance Spectrum by Electrochemical Approach
Authors: Huang Chih-Sheng , Lin Yang-Shan , Chen Kuo-Ching , Lin Chi-Hao
Published: October 2014

A simulation model to predict impedance spectrum by electrochemical approach is developed. The simulation result is validated by experimental data obtained from a LiMn2O4 lithium–ion battery. Base on the accuracy from validating simulation result of discharge curve, we use the simulation model to study the impedance spectrum variation in various degradation conditions and mismatch batteries in parallel connection.
Effects of Pore Size Distribution on the Discharge Characteristics of Li-Air Batteries with Organic Electrolyte
Authors: Andrei Petru , Bevara Vamsci V
Published: October 2014

The effects of the pore size distribution on the discharge characteristics of Li-air batteries with organic electrolyte are investigated. The theory of concentrated solutions is used to solve the transport equations in the electrolyte, which include oxygen diffusion, anion and cation drift and diffusion, reaction product deposition in the cathode, and Butler-Volmer kinetics. It is shown that the pore size distribution has a significant effect on the specific area in the cathode, specific capacity, and discharge characteristics of the battery: the specific area, the specific capacity and the voltage drop decrease when the standard deviation of the pore radius increases; the specific capacity increases when the average value of the pore radius increases. In addition, we found that the specific capacity of lithium-air batteries does not depend monotonically on the resistivity of the discharge product. The finite resistivity of the deposit layer has a positive effect on the performance of the battery by slightly increasing the specific capacity at low values of the resistivity. When the resistivity of the deposit layer becomes too high the specific capacity of the battery decreases abruptly with the resistivity because of the large voltage drop across the deposit layer.
Water Vapor Transport Measurement across PEMs
Authors: Yadav Ramesh , DiLeo Greg , Dale Nilesh , Oshihara Kenzo
Published: October 2014

Water vapor transport through the PEM is one of the key parameters that can help achieve high performance and low-cost fuel cell system. Ex-situ water vapor transport rate (WVTR) measurement is extremely difficult and expensive to measure. This transport depends on many parameters such as ionomer equivalent weight, ionomer type, thickness, reinforcement, and operating conditions. This work presents a simplified and an inexpensive set-up that consists of fuel cell test stand, cell hardware, and a humidity sensor to measure WVTR at PEMFCs operating conditions in order to characterize and compare water transport properties of PEMs. WVTR is found to increase with decrease in EW and decrease in thickness. WVTR shows dependence on flow rates at fixed water vapor activity and increases by almost 2 times at flow rate from 0.1 to 4 L/min. WVTR is strongly dependent on RH% and increases by 4-5 times at RH from 30 to 100%. Overall, a simple and inexpensive set-up is developed which is capable of producing water vapor transport behavior of widely different PEMs.
Highly Active Pt-Sn/C Catalysts for Ethanol Electro-Oxidation Prepared by a Polyol-Alcohol Reduction Process
Authors: González-Quijano D. , Pech-Rodríguez W.J. , Escalante-García J.I. , Vargas-Gutiérrez G. , Rodríguez-Varela F.J.
Published: October 2014

Pt-Sn/C catalysts with nominal Pt:Sn atomic ratio of 1:1 were synthesized by a polyol/alcohol reduction process. The effects of varying the volume ratio (v/o) of ethylene glycol, ethanol, and water on the physicochemical and electrochemical characteristics for the Ethanol Oxidation Reaction (EOR) of the catalyst were evaluated. The XRD patterns confirmed the formation oxides due to the presence of SnOx phases. The degree of alloying, calculated from XRD, ranged from 15 to approximately 49 %. Meanwhile, the average particle size of the catalysts determined with the Scherrer equation was found to be within 1.8-4.7 nm, in good agreement with TEM analysis. ICP-AES chemical analysis confirmed the actual content of Pt (10.84 to 13.23 wt. %) and Sn (0.55 to 6.36 wt. %). CVs of the EOR showed that the synthesis conditions have important effects on catalytic activity of the Pt-Sn/C alloys for the anodic reaction. As a result, the alloys synthesized in the absence of H2O delivered a higher performance than Pt/C and the rest of the Pt-Sn/C materials for the EOR.
Electrochemical Characterization of Pt Nanocatalysts Supported on Functionalized Vulcan XC-72 for the EOR
Authors: Pech-Rodríguez W.J. , Gonzalez-Quijano D. , Vargas-Gutierrez G. , Escalante-Garcia J.I. , Rodriguez-Varela F.J.
Published: October 2014

In this work, the effect of the functionalization of Vulcan support on the electrocatalytic behavior of Pt/C nanocatalysts for the Ethanol Oxidation Reaction (EOR) has been studied. Vulcan was functionalized via a micro-wave promoted reaction using citric acid (CA) and methanol (MeOH) as chemical agents. Pt nanoparticles were dispersed on functionalized Vulcan using Intermittent Microwave Heating (IMH) polyol reduction method. Synthesized Pt/C catalysts were characterized by XRD and SEM-EDS. Cyclic voltammetry and chronoamperometry measurements were conducted to study the behavior of the nanocatalysts during the EOR. The results showed an increase in current density of the EOR and higher stability when functionalized Vulcan was used as support for Pt catalysts.
Carbon-Based Cerium(III)-Doped Lead Dioxide Anode
Authors: Haque Inam ul
Published: October 2014

The electrocatalytic activity of cerium doped lead dioxide anode was investigated. The electrodes were prepared by electrodeposition of lead dioxide on the carbon based substrates from the bath comprising lead(II) nitrate 1.0 M and cerium(III) nitrate 0.1 M. Polarization studies of cerium doped lead dioxide electrodes were carried out using 1.0 mM iso-propanol at a scan rate of 100 mV/min in a three electrode system as shown in Figure 1. The electrooxidation of chromium(III) to chromium(VI) was also carried out using 0.3 mM chromium(III) solution and the cerium doped electrodes of area 30cm2 in divided cell. The electrolysis was run for 20 hours and the electrolyte was analyzed by visible spectroscopy. The electrochemical conversion of chromium(III) to chromium(VI) after electrolysis was 77.4% by passing 2.5 mF of charge.
Development of Fullerene Based Molecules as an Acceptor Partner with P3HT for OPV Devices in a Thin Layer Organic Solar Cell
Authors: Matsumoto Kei , Yoshimura Ken , Sugawara Kiyotaka , Uetani Yasunori , Hayase Shuichi , Nokami Toshiki , Itoh Toshiyuki
Published: October 2014

OPV devices which have 2,5-diarylfulleropyrrolidine and 1,1-diarylmethanofullerene derivatives as acceptor partners with poly(3-hexylthiophene) (P3HT) were fabricated and their OPV performances investigated. PCE values of OPV devices prepared with 2,5-diarylfulleropyrrolidines depended on both the stereochemistry and nature of the substituent: PCE of those using trans-2,5-diphenylfulleropyrrolidine, cis-2,5-di(thiophen-3-yl)fulleropyrrolidine and trans-2,5-di(thiophen-3-yl)fulleropyrrolidine were significantly lowered by PEDOT:PSS. On the other hand, cis-2,5-diphenylfulleropyrrolidine and both isomers of thiophen-2-yl-substituted compounds worked in a different mode: these are independent of the presence of PEDOT:PSS. We further found that 1,1-diarylmethanofullerene derivatives also are independent of the presence of PEDOT:PSS and showed good PCE values.
Mechanistic Study of ORR by Cu(II) Based Electrocatalyst Using Simultaneous Electrochemical EPR Spectroscopy
Authors: Zhang Congling , Lawton Jamie S. , Foister Shane , Zawodzinski Thomas A.
Published: October 2014

The mechanistic aspects of the ORR catalyzed by a non-pyrolyzed Cu-based catalyst were studied using a previously reported in situ electrochemical-EPR cell. Measurements made at a series of different O2 concentrations include calculation of Tafel slope and reaction order of O2 and Cu species in the kinetic region. The Cu-species reaction orders reveal that Cu(I) is involved in the RDS in a 1:1 complex with O2 and that Cu(II) reduced to Cu(I) is a fast step before the RDS.
Post Deposition Annealing Temperature Effect on White-Light Emitting of WOx Thin Film Stack on Si
Authors: Lin Chi-Chou , Kuo Yue
Published: October 2014

The white light emission phenomenon of the WOx solid state incandescent light emitting device with respect to the annealing temperature has been investigated. Light was emitted after being stressed with a gate voltage above the dielectric breakdown voltage. The emission light intensity increased with the increase of the post deposition annealing temperature. It increased with the magnitude of the stress voltage under the continuous driving condition or the duty cycle number in the pulsed driving scheme. The device emitted lights with high color rendering indices and stable CIE coordinates. The light emission process lasted for more than 1,300 hours continuously in air without failure except the slight change of the optical properties. The above results could be explained with the thermal excitation of the conductive path formed in the dielectric film.
Field Experience from Li-Ion BESS Delivering Primary Frequency Regulation in the Danish Energy Market
Authors: Świerczyński Maciej , Stroe Daniel Ioan , Lærke Rasmus , Stan Ana Irina , Kjær Philip Carne , Teodorescu Remus , Kær Soren Knudsen
Published: October 2014

In this paper it is presented the practical experience from operating a 1.6 MW/ 0.4 MWh lithium ion battery energy storage system, which is providing primary frequency regulation service on the Danish energy market. Aspects of the battery system requirements and the used control strategy for primary frequency regulation service are discussed. Moreover, the estimation of the battery storage system lifetime is discussed based on the results from 1.5 years periodic inspections and measured performance degradation of the both BESSs.
(Invited) Molecular Dynamics Simulation of Dipole Layer Formation at High-k/SiO2 Interfaces
Authors: Watanabe Takanobu , Kuriyama Ryo , Hashiguchi Masahiro , Takahashi Ryusuke , Shimura Kosuke , Ogura Atsushi , Satoh Shinichi
Published: October 2014

Electric dipole layer formation at high-k/SiO2 interface is reproduced by classical molecular dynamics simulation based on a simple two-body rigid ion model (1). The dipole layer was spontaneously formed by the migration of oxygen ions across the high-k/SiO2 interface. In case of Al2O3/SiO2, a part of oxygen ions of Al2O3 penetrated into the SiO2 side, resulting in the formation of a built-in potential of about 0.5 V. The opposite migration of oxygen ions, from SiO2 side to high-k oxide side, is also reproduced by using different potential parameters of ionic radius and effective charge. The simulation result suggests that the dipole is not merely formed by the oxygen density difference. Rather, oxygen ions are driven by some interatomic forces at the interface. We discuss the origin of the driving force of the oxygen migration in terms of the multipole moments around cations in the oxides.
ALD Grown Rare-Earth High-k Oxides on Ge: Lowering of the Interface Trap Density and EOT Scalability
Authors: Bethge Ole , Zimmermann Christina , Lutzer Bernhard , Simsek Sinan , Abermann Stephan , Bertagnolli Emmerich
Published: October 2014

Y2O3 and L2O3/ZrO2 stacks have been examined in terms of their electrical properties in Ge capacitors. It is discussed that scaling of L2O3/ZrO2 stacks into the sub 1 nm EOT regime can be achieved either by using thin amorphous La2O3 capped by a thin ZrO2 layer or by stabilizing the tetragonal or cubic very high-k phase of ZrO2 induced by diffused La and Ge atoms during a PDA step. Y2O3 shows very good interfacial qualities in terms of a low interface trap density and hysteresis when an annealing in O2 atmosphere is applied. Fowler-Nordheim tunneling is identified as the primary leakage current mechanism at high gate bias whereas for the low bias regime leakage current is primary conducted by direct tunneling through the Y2O3 layer.