bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of ground densification using spectral analysis of surface waves (SASW) and resonant column (RC) tests
Authors: Kim D S , Park H C
Published: April 2011

In order to assess the quality and depth of ground densification due to compaction, standard and (or) cone penetration tests are often performed before and after compaction. Both methods are intrusive and one-location tests and require a substantial amount of time to evaluate a large area, and evaluation quality is quite dependent on the operation technique and soil type. In this paper, the quality and extent of ground densification by compaction were evaluated using the results from in situ spectral analysis of surface waves (SASW) tests and laboratory resonant column (RC) tests. The SASW test was used to determine the shear wave velocity profiles before and after compaction, and the RC test was adopted to determine the correlation between the normalized shear wave velocity and density of the site, which is almost independent of confinement. Testing and data-reduction procedures of both tests were discussed, and a simplified procedure for evaluating ground densification was proposed by effectively combining in situ shear wave velocity profiles determined by SASW tests with the correlation between normalized shear wave velocity and density determined by RC tests. Finally, the feasibility of the proposed method was verified by performing field studies at the Inchon International Airport project. Field densities determined by the proposed method matched well with those determined by sand cone tests.Key words: density evaluation, densification, compaction, shear wave velocity, spectral analysis of surface waves test, resonant column test.
An approach to evaluation of field CPTU dissipation data in overconsolidated fine-grained soils
Authors: Sully John P , Robertson Peter K , Campanella Richard G , Woeller David J
Published: April 2011

Dissipation of excess pore pressures during piezocone testing in firm to stiff overconsolidated fine-grained soils provides data curves that cannot be interpreted using published theoretical solutions. Available solutions are based on either cavity-expansion or strain-path methods, which have been developed for soft, normally consolidated soils and do not adequately model the response in overconsolidated soils. During penetration in overconsolidated soils, large pore-pressure gradients and unloading can exist as the soil moves past the singularity at the cone tip shoulder; these gradients modify the initial pore-pressure distribution around the tip and along the friction sleeve and give rise to nonstandard dissipation curves. The different types of response resulting from the modified pore-pressure distribution are discussed and classified and a correction technique is proposed. In this way, the application of available theoretical models can be used to evaluate in situ flow characteristics. Examples of the different types of pore-pressure response are presented from various sites worldwide.Key words: cone penetration test, in situ, clay, overconsolidation ratio, pore pressure, dissipation, consolidation.
Appraising cone penetration test based liquefaction resistance evaluation methods: artificial neural network approach
Authors: Hsein Juang C , Chen Caroline Jinxia , Tien Yong-Ming
Published: April 2011

This paper evaluates and compares two comprehensive cone penetration test (CPT) based methods for evaluating liquefaction resistance of sandy soils. The comparison is made based on the results obtained from artificial neural network (ANN) analyses. Two methods are compared, one by Olsen and his colleagues at the Waterways Experiment Station and one by Robertson and his colleagues at the University of Alberta. ANN models are created to approximate the two CPT-based methods so that they can easily be compared using a large database. The results show that ANN models can approximate both Robertson and Olsen methods well, and that both methods are fairly accurate in predicting liquefaction resistance. The Robertson method has a success rate of 89% in predicting liquefied cases, a success rate of 76% in predicting nonliquefied cases, and an overall success rate of 84%. The success rates for the Olsen method are 68%, 89%, and 77%, respectively, in predicting liquefied cases, nonliquefied cases, and all cases. Both methods are considered accurate in predicting liquefaction resistance of sandy soils. The Robertson method is slightly more accurate than the Olsen method. The issue of the propagation of potential uncertainties in the soil parameters and solution model is also discussed.
Measured and predicted time-dependent stress-strain behaviour of Hong Kong marine deposits
Authors: Yin Jian-Hua , Zhu Jun-Gao
Published: April 2011

Hong Kong marine deposits (HKMD) are considered to be difficult (or weak) soils for civil projects because of low shear strength and time-dependent high compressibility. Understanding and modelling the time-dependent stress-strain behaviour of HKMD are of practical significance in the analysis and design of civil structures on and in HKMD. In this technical note, test data on the time-dependent behaviour of a remoulded HKMD are presented and analysed. An existing elastic viscoplastic (EVP) modelling framework is used to describe the time-dependent stress-strain behaviour of HKMD. The modelling results are compared with the measured results.Key words: stress-strain, time dependent, creep, viscoplastic, triaxial, soil.
A geotechnical investigation of marine deposits in a nearshore seabed for land reclamation
Authors: Lee Kin-Man , Ng Patrick CC
Published: April 2011

The properties of marine deposits in a nearshore seabed at a land reclamation site in Hong Kong were investigated. A variety of laboratory and in situ tests were conducted to define the geotechnical and consolidation characteristics of the marine deposits. The reliability and applicability of various laboratory and in situ testing techniques in evaluating the coefficient of consolidation were examined. Coefficients of consolidation were calculated from conventional oedometer tests, large-diameter (250 mm) Rowe cell tests, field permeability tests, and piezocone dissipation tests. Three techniques were adopted to evaluate the horizontal coefficient of consolidation ch from the results of in situ piezocone dissipation tests. Results from in situ pore pressure dissipation tests are compared with those from large-diameter Rowe cell tests performed on undisturbed samples under both vertical and horizontal drainage conditions and in situ permeability tests to provide reference values of the vertical coefficient of consolidation cv and ch. The engineering implications, particularly those related to land reclamation work in the nearshore environment, of various laboratory and field tests are discussed.
ON THE STATIC SPACETIME OF A SINGLE POINT CHARGE
Authors: TAHVILDAR-ZADEH A. SHADI
Published: April 2011

Among all electromagnetic theories which (a) are derivable from a Lagrangian, (b) satisfy the dominant energy condition, and (c) in the weak field limit coincide with classical linear electromagnetics, we identify a certain subclass with the property that the corresponding spherically symmetric, asymptotically flat, electrostatic spacetime metric has the mildest possible singularity at its center, namely, a conical singularity on the time axis. The electric field moreover has a point defect on the time axis, its total energy is finite, and is equal to the ADM mass of the spacetime. By an appropriate scaling of the Lagrangian, one can arrange the total mass and total charge of these spacetimes to have any chosen values. For small enough mass-to-charge ratio, these spacetimes have no horizons and no trapped null geodesics. We also prove the uniqueness of these solutions in the spherically symmetric class, and we conclude by performing a qualitative study of the geodesics and test-charge trajectories of these spacetimes.
WDM DEMULTIPLEXING BY USING SURFACE PLASMON POLARITONS
Authors: MYNBAEV DJAFAR K. , SUKHARENKO VITALY
Published: April 2011

The volume of telecommunications traffic keeps growing at an exponential rate. The optical-communications industry, the linchpin of modern telecommunications, in its quest of keeping up with this growth simply must increase the number of wavelengths in the wavelength-division multiplexing (WDM) configuration. The result of this increase would mean, too, that the number of transmitters and receivers that could be placed on one board would increase as well; hence, the density of their packaging would come to micro- and even nano-scale. At the receiver end, which we will consider in this paper, manufacturers are now able to fabricate an array of photodiodes (PDs) on a single wafer, reducing the size of an individual PD to hundreds of nm. The main obstacle in approaching this scale from a communications link point of view, however, is the diffraction limit. One possible solution to this problem is the use of plasmonics. This paper discusses a possible approach to using surface plasmon polaritons (SPPs) for WDM demultiplexing, presents a possible scheme to implement this approach, and offers our analysis of this scheme along with suggestions for future developments.
LOW FREQUENCY NOISE AND INTERFACE DENSITY OF TRAPS IN InGaAs MOSFETs WITH GdScO3 HIGH-K DIELECTRIC
Authors: RUMYANTSEV S. , STILLMAN W. , SHUR M. , HEEG T. , SCHLOM D.G. , KOVESHNIKOV S. , KAMBHAMPATI R. , TOKRANOV V. , OKTYABRSKY S.
Published: April 2011

Insulated gate n-channel enhancement mode InGaAs field effect transistors with the GdScO 3 high-k dielectric have been fabricated and studied. The low frequency noise was high indicating a high interface density of traps. Trap density and its dependence on the gate voltage have been extracted from the noise and conductance measurements.
III-V COMPOUND SEMICONDUCTOR NANOWIRES FOR OPTOELECTRONIC DEVICE APPLICATIONS
Authors: GAO Q. , JOYCE H. J. , PAIMAN S. , KANG J. H. , TAN H. H. , KIM Y. , SMITH L. M. , JACKSON H. E. , YARRISON-RICE J. M. , ZOU J. , JAGADISH C.
Published: April 2011

GaAs and InP based III-V compound semiconductor nanowires were grown epitaxially on GaAs (or Si ) (111)B and InP (111)B substrates, respectively, by metalorganic chemical vapor deposition using Au nanoparticles as catalyst. In this paper, we will give an overview of nanowire research activities in our group. In particular, the effects of growth parameters on the crystal structure and optical properties of various nanowires were studied in detail. We have successfully obtained defect-free GaAs nanowires with nearly intrinsic exciton lifetime and vertical straight nanowires on Si (111)B substrates. The crystal structure of InP nanowires, i.e., WZ or ZB , can also be engineered by carefully controlling the V/III ratio and catalyst size.
ELECTRON HEATING IN QUANTUM-DOT STRUCTURES WITH COLLECTIVE POTENTIAL BARRIERS
Authors: CHIEN L.H. , SERGEEV A. , VAGIDOV N. , MITIN V. , BIRNER S.
Published: April 2011

Here we report our research on quantum-dot structures with collective barriers surrounding groups of quantum dots (planes, clusters etc) and preventing photoelectron capture. Employing Monte-Carlo simulations, we investigate photoelectron kinetics and calculate the photoelectron lifetime as a function of geometrical parameters of the structures, dot occupation, and electric field. Results of our simulations demonstrate that the capture processes are substantially suppressed by the potential barriers and enhanced in strong electric fields. Detailed analysis shows that the effects of the electric field can be explained by electron heating, i.e. field effects become significant, when the shift of the electron temperature due to electron heating reaches the barrier height. Optimized photoelectron kinetics in quantum-dot structures with collective barriers allows for significant improvements in the photoconductive gain, detectivity, and responsivity of photodetectors based on these structures.
NOVEL APPROACHES TO MICROWAVE SWITCHING DEVICES USING NITRIDE TECHNOLOGY
Authors: SIMIN G. , WANG J. , KHAN B. , YANG J. , SATTU A. , GASKA R. , SHUR M.
Published: April 2011

III-Nitride heterostructure field-effect transistors (HFETs) demonstrated a new paradigm in microwave switching and control applications due to unique combination of extremely low channel resistance (leading to low loss), very high RF power, low off-state capacitance, broad range of operating temperatures, chemical inertness and robustness. The paper reviews novel approaches and recent advances in III-Nitride technology for RF switching devices leading to higher operating frequencies and even lower insertion loss.
TSV Cu Plating and Implications for CMP
Authors: Radisic Aleksandar , Philipsen Harold , Honore Mia , Wang Yu-Shuen , Heylen Nancy , El-Mekki Zaid , Armini Silvia , Vandersmissen Kevin , Rodet Simon , Van Ammel Annemie , Bender Hugo , Drijbooms Christel , Vanstreels Kris , Ruythooren Wouter
Published: April 2011

In the work presented here, we focused on fabrication of Cu nails for 3D Stacked-Integrated-Circuits (3D-SIC) applications using electrochemical deposition from the bath with model ('open source') additives. We have studied the effects of bath composition on the Cu fill profile and overburden, and have also examined the correlations between phenomena observed during post-plating-processing and bath composition. Based on these results, we explored different approaches to improving Cu removal rate during Chemical Mechanical Polishing (CMP).
Adsorption/Desorption of Suppressor Complex on Copper: Description of the Critical Potential
Authors: Atanasova Tanya A. , Strubbe Katrien , Vereecken Philippe M.
Published: April 2011

The acid cupric sulfate solutions, used for Damascene copper plating, contain several additives which provide the differential deposition rate inside cavities for void-free fill. Most of the models for this process, available in the literature, can successfully predict trends. However, these models miss fines as they are based on physical adsorption only. Since the copper surface has a complex chemistry, a physicochemical approach is needed to describe all the reaction mechanisms involved. In this work we provide some further insight into the thermodynamics of copper deposition inhibition by the suppressor polymer. The quantitative participation of each solution component is discussed and the adsorption/desorption reaction for the suppression is balanced based on the achieved results. In addition, a value for the standard critical potential was obtained which made possible the solubility constant for the Cu(I)-Suppressor-Cl complex to be estimated.
Microstructure of Electrodeposited Nano-Crystalline Au-Ni Alloy Films
Authors: Inoue Takahiro , Sato Kazuo , Yokoshima Tokihiko , Sawaguchi Takahiro , Sugiyama Atsushi , Okinaka Yutaka , Osaka Tetsuya
Published: April 2011

The microstructure of electrodeposited Au-Ni films was investigated by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning transmission electron microscopy (STEM). Nano-crystalline films were found to be composed of three different phases: Au-rich crystalline phase, Ni-rich crystalline phase, and Ni-rich amorphous phase. Particles of carbon measuring 5 to 20 nm were also found in the deposit. It is assumed that the inclusion of a large amount of carbon particles causes the formation of the amorphous phase. The microstructure and the state of dispersion of the carbon particles were also investigated. The results of TEM and STEM observations showed that the carbon particles possess either the graphite structure or the amorphous structure with some of the particles being arranged in arrays. Scanning tunneling microscopy (STM) was performed to study the relationship between the structure of species adsorbed on the electrode surface and the process of carbon inclusion.
Microelectrochemical Investigation of Hydrogen Absorption and Dissolution Behavior of MnS Inclusions in Carbon Steel
Authors: Muto Izumi , Shinozaki Jun , Omura Tomohiko , Numata Mitsuhiro , Hara Nobuyoshi
Published: April 2011

Microelectrochemical polarization and silver decoration techniques were performed on the small area with and without MnS inclusions. MnS inclusions were found to be partially dissolved in the potential range from 0.15 to -0.45 V (vs. Ag/AgCl, 3.33 M KCl) in a boric-borate buffer (pH 8.45) with 10 mM NaCl, whereas the entire surface of the inclusions was dissolved below and above this potential range. Silver deposition occurred only on and around MnS inclusions below -0.2 V, which generally corresponded to the stable region of hydrogen sulfide ions. When MnS inclusions partially dissolved, silver deposition occurred only in the dissolved area. The dissolution species from MnS inclusions seems to promote hydrogen absorption reaction.
High Efficiency Organic Bistable Light-Emitting Diodes with Little Efficiency Roll-Off
Authors: Yook Kyoung Soo , Jeon Soon Ok , Kim Oh Young , Lee Jun Yeob
Published: April 2011

Highly efficient organic bistable light-emitting diodes (OBLEDs) were developed using the tandem structure of organic light-emitting diodes and organic bistable memory. A high external quantum efficiency (> 19.0%) was obtained in the OBLED by combining a green phosphorescent organic light-emitting diode and polymer resistive memory. High quantum efficiency was observed in the OBLED at both the off and on states. The high quantum efficiency was maintained up to high luminance with little efficiency roll-off.
Process Parameter Control for the Formation of Porous Silicon through Nanoporous Alumina Using Pulsed Anodization
Authors: Bhattacharya Neelanjan , Das Biswajit
Published: April 2011

This paper discusses the formation of porous silicon through porous alumina using pulsed anodization for various parameters of anodization, type of acid for the formation of porous alumina, and their characterization using photoluminescence. The porous alumina has been synthesized using sulfuric, oxalic and phosphoric acids and luminescent porous silicon through the porous alumina has been obtained in each case. The porous silicon through porous alumina formation has also been investigated using pulsed anodization. The duty cycle and frequency of the square wave pulse have been varied and the optical properties of the porous silicon, so formed, through the porous alumina, have been investigated.
Fabrication of Variable Diameter Thin Film Porous Alumina Using Alternate Cycles of Mild and Hard Anodization
Authors: Bhattacharya Neelanjan , Das Biswajit
Published: April 2011

This paper reports fabrication of thin film porous anodic alumina with variable diameter pores using alternate cycles of mild and hard anodization. The formation of modulated pore structures on bulk porous alumina has been reported. In this paper, the formation of variable diameter porous alumina in thin films has been studied using current-time graphs obtained during anodization and SEM images. The impact of different process parameters on pore diameter variability has been discussed and device applications suggested
Investigation on the Hardness and Morphology of Be-Cu for Probing Al Layers
Authors: Saito Mikiko , Kimoto Gunsei , Homma Takayuki
Published: April 2011

In this study, we evaluate the hardness and morphology of Al layers, which are constructed using Al / Si and alumina / Al / Si. The depth of the hollow in the Al sample, which has native oxide, was measured as 0.5 μm using a Be-Cu probe under the applied force of 10 mN. The relationship between the applied force and the displacement can be explained by the Hertzian theory. In the case of alumina (20 nm, 50 nm) / Al / Si, the hollows were smaller than those predicted by the Hertzian theory. Cross-sectional observations revealed that the Al layer under alumina was deformed vertically and laterally. It was concluded that the breaking of alumina was induced by the deformation of Al.
Usage Of Porous Indium Phosphide as Substrate for Indium Nitride Films
Authors: Suchikova Y.A. , Kidalov Valeriy , Konovalenko Anatoliy , Sukach G.A.
Published: April 2011

In this paper the possibility of obtaining thin InN films on porous InP substrates by radical-beam gettering epitaxy is considered. Porous InP prepared by electrochemical etching. On the surface of porous InP by Auger spectroscopy proved the formation of films of InN.
(High Temperature Materials Division Outstanding Achievement Award) Measurement and Modeling of Electrical, Mechanical, and Chemical Properties of a Model Mixed Ionic Electronic Conductor: Pr Doped Ceria
Authors: Bishop Sean R. , Chen Di , Kuru Yener , Kim Jae-Jin , Stefanik Todd , Tuller Harry L.
Published: April 2011

Praseodymium doped cerium oxide (PCO) shows mixed ionic and electronic conducting (MIEC) characteristics at relatively high pO2 (e.g. air) and enhanced oxygen storage capacity (OSC) resulting from the ready reduction of Pr to its trivalent state. These features are important in applications such as solid oxide fuel cell (SOFC) cathodes and permeation membranes, oxygen buffers in three-way catalysts, and gas sensors. In this proceedings article, we present an overview of our current and past efforts towards the electrical, chemical, mechanical, and optical characterization of PCO.
Mixed Oxide-Ion and Carbonate-Ion Conductors (MOCCs) as Electrolyte Materials for Solid Oxide Fuel Cells
Authors: Li Xue , Xiao Guoliang , Lee Seung Min , Huang Kevin
Published: April 2011

A systematic investigation on the effective ionic conductivity (σm) of a novel intermediate temperature mixed oxide-ion and carbonate-ion conductor (MOCC) consisting of a ceria and a carbonate is reported. The study explicitly shows that the observed remarkable temperature-dependent σm is primarily the result of softening/melting of the carbonate phase as the physical state of the carbonate phase transforms from solid, softened to molten. DSC analysis complements the understanding of the observed electrical behavior by revealing temperatures of melting and solidification in agreement with the onset temperatures of σm. In addition, the measured σm agrees reasonably well with those simulated by the Effective Medium Percolation Theory (EMPT). Furthermore, σm of the MOCC is independent of atmosphere at t<600oC, exhibiting the characteristics of a good electrolyte. Finally, no sign of σm degradation measured at 600oC in air is found over a three-day period.
Electrochemical Performances of a Thin Film Type SOFC on a Porous Microtubular Support
Authors: Yamaguchi Toshiaki , Sammes Nigel
Published: April 2011

This report summarizes electrochemical performances of a thin film type SOFC prepared on a porous microtubular support. The sample was prepared via the co-sintering of YSZ electrolyte and NiO-YSZ anode bilayers on a porous microtubular YSZ support, and then an LSCF-GDC cathode layer was also prepared on the electrolyte film. Evaluations were conducted using impedance analyzer and potentio/galvanostat under a humidified hydrogen flow. Film thickness of the anode layer was controlled by the composition of the anode coating suspension and the coating conditions (coating number and coating speed etc.). Impedance analyses showed that with increasing operation temperature, semi-circle at higher frequency region became small, while semi-circle at lower frequency region weakly depended on the temperature. Electrode activation energy was calculated to be approximately 80 kJ/mol using Arrhenius plot on the semi-circle at higher frequency region.
Electrochemical Analysis of Microtubular SOFC under Fuel Contaminants
Authors: Andres Lozano Carlos , Ohashi Masato , Shimpalee Sirivatch , Van Zee John W. , Aungkavattana Pavadee
Published: April 2011

In the present study, the SOFC which are built by the National Metal and Materials Technology Center (MTEC) in Thailand were electrochemically characterized using polarization and transient techniques. The effect of diluting hydrogen with argon was studied and also the impact that the use of methane, as a zero order contaminant, was evaluated. To quantify the amount of carbon deposition, mass spectroscopy was used with samples collected at the outlet of the fuel cell during and after methane. The results obtained show that very small, and reversible, carbon deposition could be seen, as long as some current was applied to the fuel cell. However, if no current was applied while methane was flown, much stronger carbon deposition could be seen. This carbon deposition, at open circuit voltage proved to be irreversible leading to cell failure.
Morphological Transformations and Electrochemical Properties of Hydrothermally Synthesized MnO2 Nanostructures
Authors: Shahani Ashwin , Wu Jingjie , Wu Laying , Wang Qian , Zhou Xiao-Dong
Published: April 2011

MnO2 nanostructures with various morphologies were synthesized by the hydrothermal method with control over the reaction temperature and dwell time. One dimensional (1D) nanoneedle structure can self-assemble to form three dimensional (3D) microspheres of MnO2 nanoneedles at 95oC by extending the dwell time from 3 hours to 15 hours. Alternatively, the 3D microspheres of nanoneedles can transform into 1D nanobelts and nanorods by increasing the reaction temperature to 120oC and 165oC, respectively, while maintaining constant dwell time of 15 hours. The supercapacitance of these nanostructures shows strong morphology dependence, and nanobelts have the highest specific capacitance of 323.7 F g-1.
Graphene Platelets and their Manganese Composites for Lithium- Ion Batteries
Authors: Cheekati Sree , Xing Yun , Zhuang Yan , Huang Hong
Published: April 2011

In comparison with graphitic carbons, graphene oxide and transition metal oxides can reversibly store/release over twice amount of lithium per mass. In this research, lithium storage characteristics in graphene oxide (GO) and GO/manganese oxide (GO/Mn3O4) composites were studied, which are advantageous in terms of low cost and environmental benign. The prepared GO delivered reversible capacities of 790 mAh/g with an average columbic efficiency of 95%. The capacity decreased dramatically after GO was thermally annealed 400°C resulting from the 3D stacking of graphene layers into the turbostratic misalignment. The GO/Mn3O4 composites exhibited reversible capacities up to 860 mAh/g based on the total mass, corresponding to 900 mAh per gram of Mn3O4 close to theoretical value. The high reversible capacities and good cyclic stability of the GO/Mn3O4 composites can be attributed to the formation of nano size particles of Mn3O4 and enhanced electronic and mechanical properties in the presence of graphene.
A New Charging Method for Li-Ion Batteries: Dependence of the Charging Time on the Direction of an Additional Oscillating Field
Authors: Abou Hamad Ibrahim , Novotny Mark , Wipf David , Rikvold Per Arne
Published: April 2011

We have recently proposed a new method for charging Li-ion batteries based on large-scale molecular dynamics studies (I. Abou Hamad et al, Phys. Chem. Chem. Phys., 12, 2740 (2010)). Applying an additional oscillating electric field in the direction perpendicular to the graphite sheets of the anode showed an exponential decrease in charging time with increasing amplitude of the applied oscillating field. Here we present new results exploring the effect on the charging time of changing the orientation of the oscillating field. Results for oscillating fields in three orthogonal directions are compared.
EIS Measurements for Determining the SoC and SoH of Li-Ion Batteries
Authors: Mingant Rémy , Bernard Julien , Sauvant Moynot Valerie , Delaille Arnaud , Mailley Sophie , Hognon Jean-Luc , Huet François
Published: April 2011

In the framework of the ALIDISSI project of the Stock-E program funded by the French Research National Agency (ANR), electrochemical impedance spectroscopy (EIS) has been used as a non intrusive tool to perform in-situ diagnosis of batteries for applications dedicated to hybrid electric vehicles and grid-connected photovoltaic solar energy. EIS measurements were performed on 3-electrode coffee bag Li-ion cells during cycling with the aim of identifying the ageing mechanisms in these applications and determining impedance parameters related to the State-of-Charge (SoC) and State-of-Health (SoH) of the cells. EIS diagrams were modeled with electric equivalent circuits and, using an automatic spectra treatment, SoC and SoH prediction algorithms based on a multivariate mathematical analysis were obtained. They give a 10% SoC error on commercial LiFePO4/graphite cells and a 7% SoH error on LiFePO4/Li4Ti5O12 cells with EIS measurements performed at 20 degrees.
Electrochemical Impedance Spectroscopy of Liquid Tin Anode Solid Oxide Fuel Cell
Authors: Rayman Sean C. , Koslowske Mark , Bateman Linda , Tao Thomas , White Ralph E.
Published: April 2011

Solid oxide fuel cells (SOFCs) can convert the chemical energy stored in hydrocarbon fuels directly into electricity bypassing the many energy transfers that normally occur, (chemical→ heat (steam boiler)→ mechanical (turbine)→ electrical (generator)), when hydrocarbon fuels are combusted to produce electricity. CellTech Power has developed a liquid tin anode (LTA) SOFC that is not damaged by fuels that contain sulfur. This paper develops an analytical electrochemical impedance spectroscopy model from first principals for the the LTA-SOFC anode half cell. The model is in conjunction with experimental data to determine; the average Ohmic resistance, 8.81mΩ, average steady state concentration of tin oxide in liquid tin, 1.09E-9 mol/cm3, effective diffusion coefficient of tin oxide through liquid tin, 0.198 cm2/s, and the pre-exponential factor for the butler volmer equation 2.92E5 C*cm/mol/s.
Porous Cathode Transient One Dimensional Model of a Liquid Tin Anode Solid Oxide Fuel Cell
Authors: Rayman Sean C. , Sikha Godfrey , Koslowske Mark , Tao Thomas , White Ralph E.
Published: April 2011

Solid oxide fuel cells (SOFCs) can convert the chemical energy stored in hydrocarbon fuels directly into electricity bypassing the many energy transfers that normally occur, chemical→ heat (steam boiler)→ mechanical (turbine)→ electrical (generator), when hydrocarbon fuels are combusted to produce electricity. CellTech Power has developed a liquid tin anode (LTA) SOFC that is not damaged by fuels that contain sulfur. This paper expands the 1-D model of the LTA-SOFC by using porous electrode theory for the cathode, which facilitates the prediction of concentration polarization experimentally observed at higher current densities. The results of this study indicate that the tortuosity of the cathode and the lanthanum strontium manganate (LSM) layer should be as close to unity as possible, and that the porosity of the LSM should be between 0.4 and 0.8 while the porosity of the cathode should be 0.2.
Novel Electrolyte Chemistries for Mg-Ni Rechargeable Batteries
Authors: Kane Marie , Garcia-Diaz Brenda , Au Ming
Published: April 2011

A new electrolyte chemistry is suggested to replace aqueous-based alkaline solutions for Mg-Ni rechargeable batteries that have high theoretical energy density, low cost, long cycle life, and no safety issues. The addition of potassium hydroxide and nano-sized clay particles to polyvinyl alcohol both increase conductivity to nearly 0.1 S/cm. The clay particles reduce the polymer crystallinity, thus increase conductivity; although the addition of more than 5 wt% clay actually reduces conductivity values. A mechanism is suggested for this behavior that includes the interaction of the clay with ion channels within the polymer helix.
Polyamines mediate glutamine-dependent induction of the intestinal epithelial heat shock response
Authors: Iwashita Yuji , Sakiyama Toshio , Musch Mark W. , Ropeleski Mark J. , Tsubouchi Hirohito , Chang Eugene B.
Published: April 2011

Heat shock proteins (Hsps) are highly conserved proteins that play a role in cytoprotection and maintaining intestinal homeostasis. Glutamine is essential for the optimal induction of intestinal epithelial Hsp expression, but its mechanisms of action are incompletely understood. Glutamine is a substrate for polyamine synthesis and stimulates the activity of ornithine decarboxylase (ODC), a key enzyme for polyamine synthesis, in intestinal epithelial cells. Thus we investigated whether polyamines (putrescine, spermidine, or spermine) and their precursor ornithine mediate the induction of Hsp expression in IEC-18 rat intestinal epithelial cells. As previously observed, glutamine was required for heat stress induction of Hsp70 and Hsp25, although it had little effect under basal conditions. Under conditions of glutamine depletion, supplementation of ornithine or polyamines restored the heat-induced expression of Hsp70 and Hsp25. When ODC was inhibited by α-difluoromethylornithine (DFMO), an irreversible ODC inhibitor, the heat stress induction of Hsp70 and Hsp25 was decreased significantly, even in the presence of glutamine. Ornithine, polyamines, and DFMO did not modify the nuclear localization of heat shock transcription factor 1 (HSF-1). However, DFMO dramatically reduced glutamine-dependent HSF-1 binding to an oligonucleotide with heat shock elements (HSE), which was increased by glutamine. In addition, exogenous polyamines recovered the DNA-binding activity. These results indicate that polyamines play a critical role in the glutamine-dependent induction of the intestinal epithelial heat shock response through facilitation of HSF-1 binding to HSE.
Laser-based absorption spectroscopy as a technique for rapid in-line analysis of respired gas concentrations of O2 and CO2
Authors: Cummings Beth , Hamilton Michelle L. , Ciaffoni Luca , Pragnell Timothy R. , Peverall Rob , Ritchie Grant A. D. , Hancock Gus , Robbins Peter A.
Published: April 2011

The use of sidestream analyzers for respired gas analysis is almost universal. However, they are not ideal for measurements of respiratory gas exchange because the analyses are both temporally dissociated from measurements of respiratory flow and also not generally conducted under the same physical conditions. This study explores the possibility of constructing an all optical, fast response, in-line breath analyzer for oxygen and carbon dioxide. Using direct absorption spectroscopy with a diode laser operating at a wavelength near 2 μm, measurements of expired carbon dioxide concentrations were obtained with an absolute limit of detection of 0.04% at a time resolution of 10 ms. Simultaneously, cavity enhanced absorption spectroscopy at a wavelength near 760 nm was employed to obtain measurements of expired oxygen concentrations with an absolute limit of detection of 0.26% at a time resolution of 10 ms. We conclude that laser-based absorption spectroscopy is a promising technology for in-line analysis of respired carbon dioxide and oxygen concentrations.
Relationship between leg muscle capillary density and peak hyperemic blood flow with endurance capacity in peripheral artery disease
Authors: Robbins Jennifer L. , Jones W. Schuyler , Duscha Brian D. , Allen Jason D. , Kraus William E. , Regensteiner Judith G. , Hiatt William R. , Annex Brian H.
Published: April 2011

The aim of this study was to determine if skeletal muscle capillary density is lower in patients with peripheral artery disease (PAD) and if capillary density relates to functional limitations. PAD patients with intermittent claudication (IC) have a decreased exercise tolerance due to exercise-induced muscle ischemia. Despite the apparent role diminished arterial flow has in this population, the degree of walking pain and functional limitation is not entirely explained by altered hemodynamics of the affected limbs. We hypothesized that skeletal muscle capillary density is lower in PAD and is related to the functional impairment observed in this population. Sixty-four patients with PAD and 56 controls underwent cardiopulmonary exercise testing and a gastrocnemius muscle biopsy. A subset of these patients (48 PAD and 47 controls) underwent peak hyperemic flow testing via plethysmography. Capillary density in PAD patients was lower compared with controls ( P < 0.001). After adjustment for several baseline demographic imbalances the model relating capillary density to peak oxygen consumption (V̇o2) remained significant ( P < 0.001). In PAD subjects, capillary density correlated with peak V̇o2, peak walking time (PWT), and claudication onset time (COT). Peak hyperemic blood flow related to peak V̇o2 in both PAD and control subjects. PAD is associated with lower capillary density, and capillary density is related to the functional impairment as defined by a reduced peak V̇o2, PWT, and COT. These findings suggest that alterations in microcirculation may contribute to functional impairment capacity in PAD.
Interactions between intracellular calcium and phosphate in intact mouse muscle during fatigue
Authors: Allen D. G. , Clugston E. , Petersen Y. , Röder I. V. , Chapman B. , Rudolf R.
Published: April 2011

Fatigue was studied in intact tibialis anterior muscle of anesthetized mice. The distal tendon was detached and connected to a force transducer while blood flow continued normally. The muscle was stimulated with electrodes applied directly to the muscle surface and fatigued by repeated (1 per 4 s), brief (0.4 s), maximal (100-Hz stimulation frequency) tetani. Force declined monotonically to 49 ± 5% of the initial value with a half time of 36 ± 5 s and recovered to 86 ± 4% after 4 min. Intracellular phosphate concentration ([Pi]) was measured by31P-NMR on perchloric acid extracts of muscles. [Pi] increased during fatigue from 7.6 ± 1.7 to 16.0 ± 1.6 mmol/kg muscle wet wt and returned to control during recovery. Intracellular Ca2+was measured with cameleons whose plasmids had been transfected in the muscle 2 wk before the experiment. Yellow cameleon 2 was used to measure myoplasmic Ca2+, and D1ER was used to measure sarcoplasmic reticulum (SR) Ca2+. The myoplasmic Ca2+during tetani declined steadily during the period of fatigue and showed complete recovery over 4 min. The SR Ca2+also declined monotonically during fatigue and showed a partial recovery with rest. These results show that the initial phase of force decline is accompanied by a rise in [Pi] and a reduction in the tetanic myoplasmic Ca2+. We suggest that both changes contribute to the fatigue. A likely cause of the decline in tetanic myoplasmic Ca2+is precipitation of CaPiin the SR.
Surface contamination artificially elevates initial sweat mineral concentrations
Authors: Ely Matthew R. , Kenefick Robert W. , Cheuvront Samuel N. , Chinevere Troy D. , Lacher Craig P. , Lukaski Henry C. , Montain Scott J.
Published: April 2011

Several sweat mineral element concentrations decline with serial sampling. Possible causes include reduced dermal mineral concentrations or flushing of surface contamination. The purpose of this study was to simultaneously sample mineral concentrations in transdermal fluid (TDF), sweat, and serum during extended exercise-heat stress to determine if these compartments show the same serial changes during repeat sampling. Sixteen heat-acclimated individuals walked on a treadmill (1.56 m/s, 3.0% grade) in a 35°C, 20% relative humidity (RH), 1 m/s wind environment 50 min each hour for 3 h. Mineral concentrations of Ca, Cu, Fe, K, Mg, Na, and Zn were measured each hour from serum, sweat from upper back (sweat pouch) and arm (bag), and TDF from the upper back. Sites were meticulously cleaned to minimize surface contamination. Mineral concentrations were determined by spectrometry. TDF remained stable over time, with exception of a modest increase in TDF [Fe] (15%) and decrease in TDF [Zn] (−18%). Likewise, serum and pouch sweat samples were stable over time. In contrast, the initial arm bag sweat mineral concentrations were greater than those in the sweat pouch, and [Ca], [Cu], [Mg], and [Zn] declined 26–76% from initial to the subsequent samples, becoming similar to sweat pouch. Nominal TDF mineral shifts do not affect sweat mineral concentrations. Arm bag sweat mineral concentrations are initially elevated due to skin surface contaminants that are not removed despite meticulous cleaning (e.g., under fingernails, on arm hair), then decrease with extended sweating and approach those measured from the scapular region.
An EGFR-ERK-SOX9 Signaling Cascade Links Urothelial Development and Regeneration to Cancer
Authors: Ling Shizhang , Chang Xiaofei , Schultz Luciana , Lee Thomas K. , Chaux Alcides , Marchionni Luigi , Netto George J. , Sidransky David , Berman David M.
Published: April 2011

Like many carcinomas, urothelial carcinoma (UroCa) is associated with chronic injury. A better understanding of this association could inform improved strategies for preventing and treating this disease. We investigated the expression, regulation, and function of the transcriptional regulator SRY-related high-mobility group box 9 (Sox9) in urothelial development, injury repair, and cancer. In mouse bladders, Sox9 levels were high during periods of prenatal urothelial development and diminished with maturation after birth. In adult urothelial cells, Sox9 was quiescent but was rapidly induced by a variety of injuries, including exposure to the carcinogen cyclophosphamide, culture with hydrogen peroxide, and osmotic stress. Activation of extracellular signal–regulated kinases 1/2 (ERK1/2) was required for Sox9 induction in urothelial injury and resulted from activation of the epidermal growth factor receptor (Egfr) by several Egfr ligands that were dramatically induced by injury. In UroCa cell lines, SOX9 expression was constitutively upregulated and could be suppressed by EGFR or ERK1/2 blockade. Gene knockdown showed a role for SOX9 in cell migration and invasion. Accordingly, SOX9 protein levels were preferentially induced in invasive human UroCa tissue samples (n = 84) compared with noninvasive cancers (n = 56) or benign adjacent urothelium (n = 49). These results identify a novel, potentially oncogenic signaling axis linking urothelial injury to UroCa. Inhibiting this axis is feasible through a variety of pharmacologic approaches and may have clinical utility. Cancer Res; 71(11); 3812–21. ©2011 AACR.
Chronic Inflammatory IFN-γ Signaling Suppresses Hepatocarcinogenesis in Mice by Sensitizing Hepatocytes for Apoptosis
Authors: Lüth Stefan , Schrader Jörg , Zander Stefan , Carambia Antonella , Buchkremer Juliane , Huber Samuel , Reifenberg Kurt , Yamamura Ken-Ichi , Schirmacher Peter , Lohse Ansgar W. , Herkel Johannes
Published: April 2011

Chronic liver inflammation is a critical component of hepatocarcinogenesis. Indeed, inflammatory mediators are believed to promote liver cancer by upholding compensatory proliferation of hepatocytes in response to tissue damage. However, inflammation can also mediate the depletion of malignant cells, but the difference between tumor-suppressive and tumor-promoting inflammation is not defined at the molecular level. Here, we analyzed the role of the major inflammatory mediator IFN-γ in chemical hepatocarcinogenesis of transgenic mice that overexpress IFN-γ in the liver; these mice manifest severe chronic inflammatory liver damage and lasting compensatory regeneration. We found that chronic exposure to IFN-γ suppressed chemical hepatocarcinogenesis, despite overt liver injury. Indeed, IFN-γ–transgenic mice had significantly fewer and significantly less advanced malignant lesions than nontransgenic mice. This tumor-suppressive effect of IFN-γ seemed to be mediated in part by its known immune activating function, indicated by infiltration of IFN-γ–transgenic livers with CD8 T cells, natural killer T cells, and natural killer cells. However, IFN-γ seemed to prevent carcinogenesis also by activating the cell-intrinsic p53 tumor suppressor pathway. Indeed, exposure to IFN-γ in vivo or in vitro was associated with accumulation of p53 in hepatocytes and the sensitization of hepatocytes to apoptosis induced by genotoxic stress. The IFN-γ–induced increase in apoptosis of hepatocytes seemed to be p53 dependent. Thus, chronic inflammation dominated by IFN-γ may prevent hepatocarcinogenesis, despite continued inflammatory liver injury and regeneration. Therefore, the carcinogenic potential of inflammation seems to be determined by type and composition of its mediators and manipulating the type of chronic inflammation may serve the prevention of cancer. Cancer Res; 71(11); 3763–71. ©2011 AACR.
Bone Marrow Stroma–Secreted Cytokines Protect JAK2V617F-Mutated Cells from the Effects of a JAK2 Inhibitor
Authors: Manshouri Taghi , Estrov Zeev , Quintás-Cardama Alfonso , Burger Jan , Zhang Ying , Livun Ana , Knez Liza , Harris David , Creighton Chad J. , Kantarjian Hagop M. , Verstovsek Srdan
Published: April 2011

Signals emanating from the bone marrow microenvironment, such as stromal cells, are thought to support the survival and proliferation of the malignant cells in patients with myeloproliferative neoplasms (MPN). To examine this hypothesis, we established a coculture platform [cells cocultured directly (cell-on-cell) or indirectly (separated by micropore membrane)] designed to interrogate the interplay between Janus activated kinase 2-V617F (JAK2V617F)–positive cells and the stromal cells. Treatment with atiprimod, a potent JAK2 inhibitor, caused marked growth inhibition and apoptosis of human (SET-2) and mouse (FDCP-EpoR) JAK2V617F-positive cells as well as primary blood or bone marrow mononuclear cells from patients with polycythemia vera; however, these effects were attenuated when any of these cell types were cocultured (cell-on-cell) with human marrow stromal cell lines (e.g., HS5, NK.tert, TM-R1). Coculture with stromal cells hampered the ability of atiprimod to inhibit phosphorylation of JAK2 and the downstream STAT3 and STAT5 pathways. This protective effect was maintained in noncontact coculture assays (JAK2V617F-positive cells separated by 0.4-μm-thick micropore membranes from stromal cells), indicating a paracrine effect. Cytokine profiling of supernatants from noncontact coculture assays detected distinctly high levels of interleukin 6 (IL-6), fibroblast growth factor (FGF), and chemokine C-X-C-motif ligand 10 (CXCL-10)/IFN-γ–inducible 10-kD protein (IP-10). Anti-IL-6, -FGF, or -CXCL-10/IP-10 neutralizing antibodies ablated the protective effect of stromal cells and restored atiprimod-induced apoptosis of JAK2V617F-positive cells. Therefore, our results indicate that humoral factors secreted by stromal cells protect MPN clones from JAK2 inhibitor therapy, thus underscoring the importance of targeting the marrow niche in MPN for therapeutic purposes. Cancer Res; 71(11); 3831–40. ©2011 AACR.
c-Myc Regulates RNA Splicing of the A-Raf Kinase and Its Activation of the ERK Pathway
Authors: Rauch Jens , Moran-Jones Kim , Albrecht Valerie , Schwarzl Thomas , Hunter Keith , Gires Olivier , Kolch Walter
Published: April 2011

A-Raf kinase can inhibit apoptosis by binding to the proapoptotic mammalian sterile 20-like kinase (MST2). This function relies on expression of hnRNP H, which ensures the correct splicing of a-raf mRNA needed to produce full-length A-Raf protein. Here, we showed that expression of hnRNP H and production of full-length A-Raf is positively controlled by c-Myc. Low c-Myc reduces hnRNP H expression and switches a-raf splicing to produce A-Rafshort, a truncated protein. Importantly, A-Rafshort fails to regulate MST2 but retains the Ras-binding domain such that it functions as a dominant negative mutant suppressing Ras activation and transformation. Human colon and head and neck cancers exhibit high hnRNP H and high c-Myc levels resulting in enhanced A-Raf expression and reduced expression of A-Rafshort. Conversely, in normal cells and tissues in which c-Myc and hnRNP H are low, A-Rafshort suppresses extracellular signal regulated kinase activation such that it may act as a safeguard against oncogenic transformation. Our findings offered a new paradigm to understand how c-Myc coordinates diverse cell functions by directly affecting alternate splicing of key signaling components. Cancer Res; 71(13); 4664–74. ©2011 AACR.