bluuebunny/crossref_metadata_2025 huggingface dataset:
Tidal Turbine Blades: Design and Dynamic Loads Estimation Using CFD and Blade Element Momentum Theory
Authors: Faudot Ce´line , Dahlhaug Ole G.
Published: November 2011

The interest in tidal power is constantly increasing thanks to its high predictability, the huge potential of tides and the actual need for renewable energy. It explains the emergence of many tidal turbine designs, especially in Europe, often inspired from wind turbines. All of them are at a more or less early stage of development. But because of the high density of water, environmental drag forces are very large compared with wind turbines of the same capacity. Therefore the knowledge acquired by the wind industry is certainly qualitatively useful, but it has to be reconsidered to be applicable to tidal turbines. The aim of the project presented in this paper is to create a 1 MW reference tidal turbine, whose small-scaled model has been tested in the towing tank of Marintek laboratory (Trondheim, Norway). The tests focused on dynamic loads, which are an important reason of failure, and thus will help tidal turbine designers in their work by gaining valuable experience in turbine performance in various operating conditions. The chosen turbine has a horizontal axis and two blades, which have been designed using the blade element momentum theory for a diameter of 20m. This paper states the project issues and the method used to design the blades, from the hydrodynamic properties of the hydrofoils to the computational fluid dynamic analysis. The tests on the small scaled model makes it possible to validate the concept and a comparison between efficiencies obtained analytically, experimentally and with CFD computation has been performed in this paper. The maximum power coefficient experimentally obtained is 0.427, i.e. 1.4% higher than the power coefficient obtained numerically. The blade element momentum theory is then used to estimate the loads on each blade when the rotor is subjected to regular waves of many heights and periods, with the intention of ranking the parameters of importance and introducing a fatigue analysis.
Vertical Wave Impacts on Offshore Wind Turbine Inspection Platforms
Authors: Bredmose Henrik , Jacobsen Niels G.
Published: November 2011

Breaking wave impacts on a monopile at 20 m depth are computed with a VOF (Volume Of Fluid) method. The impacting waves are generated by the second-order focused wave group technique, to obtain waves that break at the position of the monopile. The subsequent impact from the vertical run-up flow on a horizontal inspection platform is computed for five different platform levels. The computational results show details of monopile impact such as slamming pressures from the overturning wave front and the formation of run-up flow. The results show that vertical platform impacts can occur at 20 m water depth. The dependence of the vertical platform load to the platform level is discussed. Attention is given to the significant downward force that occur after the upward force associated with the vertical impact. The effect of the numerical resolution on the results is assessed. The position of wave overturning is found to be influenced by the grid resolution. For the lowest platform levels, the vertical impact is found to contribute to the peak values of in-line force and overturning moment.
Deep Sea Mining With an Archimedes Screw Driven Vehicle
Authors: Lotman Rick , Grima Mario Alvarez
Published: November 2011

Archimedes screw propulsion is a proven technology for land based vehicles. Especially in rough, impassable terrain they have shown reliable operation, superior traction capabilities and they can be used as a buoyancy body. Typical working territories for Archimedes driven are dredge deposit sites and swamps. The use of Archimedes screws will also prove their value in the deep sea mining application, but it will pose special demands and requirements on the propulsion system design such as: the propulsion system must be able to operate completely submerged and remotely operated. It must also include operational aspects like moving, manoeuvring, traction, friction and to cope with the aggressive environment. It can be said that the propulsion system is an important driver for the design of the SMT. It is an important factor in the SMT total weight and it influences the handling during launch and recovery, the excavation process controllability and the mining planning. This article presents the mathematical model of the Archimedes screw propulsion as developed by IHC Merwede. The model combines the soil mechanics theory and principles and screw geometry as input parameters. The outputs of the model are bearing capacity of the seabed, buoyancy forces, friction forces, maximum realizable traction and power requirement. In order to validate the model, an experimental test setup was built in the soil laboratory at IHC Merwede in Kinderdijk, the Netherlands. Different soil types were used and various experiments were performed to measure the bearing capacity and sinkage, friction forces, traction and forces directed sideways. Valuable lessons have been learned regarding slippage, motion behaviour, adhesion, and bulldozer effects at the front side of the screws.
Response of FPSO Systems to Squalls
Authors: Duggal Arun , Heyl Caspar , Izadparast Amir H. , Minnebo Joerik
Published: November 2011

Squalls are mesoscale sudden wind-speed increases that can occur worldwide and are a design driver for FPSO systems in areas the other design environmental conditions are relatively benign, e.g. offshore West Africa. Squalls are transient winds which rapidly reach a peak wind speed (up to 50 m/s) and then decay to low speeds in a span of 60 to 90 minutes. As squalls are transient phenomena traditional steady-state analysis techniques cannot be used for the global analysis or the development of the extreme response estimates. This paper focuses on the characterization of the squall environment and the impact of various parameters on the response of FPSOs. The responses of both spread and turret moored FPSOs are presented and the difference in response is discussed. The paper then focuses on a parametric study on a representative single degree of freedom model of a spread-moored FPSO with an emphasis on the estimation of the extreme response and its dependence on sample size.
Ship Wake Structure on the Finite Sea Depth in the Presence of Wind Waves
Authors: Yang Ray-Yeng , Fang Ming-Chung , Shugan Igor V.
Published: November 2011

A kinematics model of the ship wake in the presence of surface waves, generated by wind is presented. It is found that the stationary wave structure behind the ship covered a wedge region with the 16.9° half an angle at the top of the wake and only divergent waves are present in a ship wake for co propagating wind waves. Wind waves field directed at some nonzero angle to the ship motion can cause essential asymmetry of the wake and compressing of its windward half. The extension of Whitham-Lighthill kinematics theory of ship wake for the intermediate sea depth is also presented. The ship wake structure essentially depends from the Froude (Fr) number based on the value of the sea depth and ship velocity. For Froude number less than unit both longitudinal and cross waves are presented in the wake region and Kelvin wake angle increased with Fr. For Fr>1 wake angle decreased with Froude number and finally only divergent waves directed almost normally to the ship track are presented in the very narrow ship wake.
Extensive Dynamic Analyses to Achieve Stringent Noise and Vibration Levels for an Offshore Reciprocating Compressor System
Authors: Eijk Andre´ , Elferink Hans
Published: November 2011

During the lifetime of an existing gas well, located in the D15FA/FB field in the North Sea, the pressure has dropped and consequently production is reduced. A depletion compressor had to be added to this existing platform to increase the production. This sounds easy but has been very challenging due to physical, noise and vibration restrictions. For this platform it appeared that a reciprocating compressor was the best choice based on its flexibility with respect to the specified operating conditions, available power, and efficiency. However, despite of several advantages a disadvantage of a reciprocating compressor is that it generates additional vibrations and noise in the living quarters, which are located close to the compressor system. The specified requirements, not to exceed the allowable noise limits in the living quarters and the vibration limits of the complete compressor system, could in this specific case, not be met with straightforward solutions. This presentation will explain the dynamic analysis and the efforts taken in compressor, skid, motor, piping and deck design to meet the very stringent specified requirements and to ensure a safe and reliable system for the long term operation. Special attention will be given to the measures taken to reduce the excitations acting on the platform, and the mechanical and acoustical analysis that have led to the final design of this reciprocating compressor system. The solutions that have been developed can be regarded as non-standard and have resulted in new directions in solving very demanding system requirements.
Global Analysis of a Floating Wind Turbine Using an Aero-Hydro-Elastic Model: Part 1—Code Development and Case Study
Authors: Ormberg Harald , Passano Elizabeth , Luxcey Neil
Published: November 2011

This paper describes the extension of a well proven state-of-the-art simulation tool for coupled floating structures to accommodate offshore wind turbine applications, both floating and fixed. All structural parts, i.e. rotor blades, hub, nacelle, tower, vessel and mooring system, are included in the finite element model of the complete system. The aerodynamic formulation is based on the blade element momentum theory. A control algorithm is used for regulation of blade pitch angle and electrical torque. The system response is calculated by nonlinear time domain analysis. This approach ensures dynamic equilibrium every time step and gives a proper time domain interaction between the blade dynamics, the mooring dynamics and the tower motions. The developed computer code provides a tool for efficient analysis of motions, support forces and power generation potential, as influenced by waves, wind, and current. Some key results from simulations with wind and wave loading are presented in the paper. The results are compared with results obtained with a rigid blade model and quasi-static model of the anchor lines. The modelled wind turbine is the NREL offshore 5-MW baseline wind turbine, specifications of which are publicly available. In the accompanying paper, Global Analysis of a Floating Wind Turbine Using an Aero-Hydro-Elastic Numerical Model. Part 2: Benchmark Study, results from the new analysis tool are benchmarked against results from other analysis tools.
Comparison of SCR Field Response With Analytical Predictions
Authors: Constantinides Yiannis , Chen Jen-hwa , Tran Lee , Enuganti Prahlad , Campbell Mike
Published: November 2011

Design of deepwater risers involves the use of multiple conservative design parameters to account for the uncertainty in the understanding of the behavior of complex structures. As the oil industry moves into deeper and harsher waters, the design tolerances are getting stretched. Chevron has been monitoring the structural response of a deepwater Gulf of Mexico steel catenary riser (SCR) to improve the understanding of riser behavior and to evaluate the existing analysis and design methodologies against actual field measurements. The following paper presents a selected set of results from benchmark of SCR response in storm conditions against analytical predictions, based on industry standard methodologies. The predictions are based on a finite element analysis (FEA) modeling of the riser structure with empirically formulated models for hydrodynamics and soil-structure interaction. Predicted riser response in terms of accelerations and stresses along the length are compared against field measurements showing good overall agreement.
Deepwater SCR Benchmarking Methodology
Authors: Li Songcheng , Tran Lee , Enuganti Prahlad , Campbell Mike , Constantinides Yiannis
Published: November 2011

One of the primary goals of riser monitoring is to build a database of measured riser behavior during different environmental conditions and compare against design predictions during each period. A comprehensive database of field measured riser response provides not only a dataset to benchmark riser performance but enables the calibration of design parameters for future risers. The calibrated set of design parameters would feedback to establish a more representative riser design process and provide greater confidence during future riser designs. The following paper establishes a methodology to benchmark riser behavior against software predictions with applications specific to a steel catenary riser (SCR) suspended from a spar platform. Aspects and challenges dealing with processing of inclined sensors to derive global motions and operational effects are discussed and addressed. A demonstration of the methodology is presented using field measurements from a Gulf of Mexico deepwater SCR under storm conditions. The riser behavior of interest for this study is specifically the touchdown motions and stress but additional comparisons are made along the entire riser length.
Fatigue Life Improvement of Welded Elements and Structures by Ultrasonic Impact Treatment
Authors: Kudryavtsev Yuriy , Kleiman Jacob
Published: November 2011

The ultrasonic impact treatment (UIT) is relatively new and promising process for fatigue life improvement of welded elements and structures. In most industrial applications this process is known as ultrasonic peening (UP). The beneficial effect of UIT/UP is achieved mainly by relieving of harmful tensile residual stresses and introducing of compressive residual stresses into surface layers of a material, decreasing of stress concentration in weld toe zones and enhancement of mechanical properties of the surface layers of the material. The UP technique is based on the combined effect of high frequency impacts of special strikers and ultrasonic oscillations in treated material. Fatigue testing of welded specimens showed that UP is the most efficient improvement treatment as compared with traditional techniques such as grinding, TIG-dressing, heat treatment, hammer peening and application of LTT electrodes. The developed computerized complex for UP was successfully applied for increasing the fatigue life and corrosion resistance of welded elements, elimination of distortions caused by welding and other technological processes, residual stress relieving, increasing of the hardness of the surface of materials. The UP could be effectively applied for fatigue life improvement during manufacturing, rehabilitation and repair of welded elements and structures. The areas/industries where the UP process was applied successfully include: Shipbuilding, Railway and Highway Bridges, Construction Equipment, Mining, Automotive, Aerospace. The results of fatigue testing of welded elements in as-welded condition and after application of UP are considered in this paper. It is shown that UP is the most effective and economic technique for increasing of fatigue strength of welded elements in materials of different strength. These results also show a strong tendency of increasing of fatigue strength of welded elements after application of UP with the increase in mechanical properties of the material used.
Normative health-related fitness values for children: analysis of 85347 test results on 9–17-year-old Australians since 1985
Authors: Catley Mark J , Tomkinson Grant R
Published: October 2011

Objectives

To provide sex- and age-specific normative values for health-related fitness of 9–17-year-old Australians.

Methods

A systematic literature search was undertaken to identify peer-reviewed studies reporting health-related fitness data on Australian children since 1985—the year of the last national fitness survey. Only data on reasonably representative s amples of apparently healthy (free from known disease or injury) 9–17-year-old Australians, who were tested using field tests of health-related fitness, were included. Both raw and pseudo data (generated using Monte Carlo simulation) were combined with sex- and age-specific normative centile values generated using the Lambda Mu and Sigma (LMS) method. Sex- and age-related differences were expressed as standardised effect sizes.

Results

Normative values were displayed as tabulated percentiles and as smoothed centile curves for nine health-related fitness tests based on a dataset comprising 85347 test performances. Boys typically scored higher than girls on cardiovascular endurance, muscular strength, muscular endurance, speed and power tests, but lower on the flexibility test. The magnitude of the age-related changes was generally larger for boys than for girls, especially during the teenage years.

Conclusion

This study provides the most up-to-date sex- and age-specific normative centile values for the health-related fitness of Australian children that can be used as benchmark values for health and fitness screening and surveillance systems.
Aortic arch injection with C-arm cone beam CT for radiosurgery treatment planning of cerebral arteriovenous malformations: technical note
Authors: Radvany Martin G , Ehtiati Tina , Huang Judy , Mahesh Mahadevappa , Gailloud Philippe
Published: October 2011

Background

C-arm cone beam CT (CBCT) with selective intra-arterial contrast injection combined with digital subtraction angiography (DSA) is currently used for the evaluation and treatment planning of cerebral arteriovenous malformations (AVMs). In some instances an AVM will derive its blood supply from more than one main cervical artery (carotid and/or vertebral artery) and a single-vessel injection will not adequately demonstrate the entire AVM nidus.

Methods

Three patients with cerebral AVM in whom the entire nidus could not be visualized by injection of a single cervical artery are reported. CBCT dataset acquisition was performed by intra-arterial contrast injection in the ascending thoracic aorta through a 5 F pigtail catheter. The injection of diluted iodinated contrast agent (35%) lasted 22 s at a rate of 8 ml/s for a total volume of 176 ml (61.6 ml of contrast agent). The dataset was then processed using standard reconstruction methods.

Results

Contrast injection in the ascending aorta during a single CBCT acquisition provided a volumetric dataset adequate for subsequent radiosurgical treatment planning.

Conclusion

This is a safe and effective angiographic technique for the acquisition of volumetric datasets using CBCT that are suitable for treatment planning of intracranial AVMs deriving their blood supply from more than one major cervical artery. This technique allows imaging of the entire AVM nidus during a single CBCT acquisition.
Republished error management: Descriptions of verbal communication errors between staff. An analysis of 84 root cause analysis-reports from Danish hospitals
Authors: Rabøl Louise Isager , Andersen Mette Lehmann , Østergaard Doris , Bjørn Brian , Lilja Beth , Mogensen Torben
Published: November 2011

Introduction

Poor teamwork and communication between healthcare staff are correlated to patient safety incidents. However, the organisational factors responsible for these issues are unexplored. Root cause analyses (RCA) use human factors thinking to analyse the systems behind severe patient safety incidents. The objective of this study is to review RCA reports (RCAR) for characteristics of verbal communication errors between hospital staff in an organisational perspective.

Method

Two independent raters analysed 84 RCARs, conducted in six Danish hospitals between 2004 and 2006, for descriptions and characteristics of verbal communication errors such as handover errors and error during teamwork.

Results

Raters found description of verbal communication errors in 44 reports (52%). These included handover errors (35 (86%)), communication errors between different staff groups (19 (43%)), misunderstandings (13 (30%)), communication errors between junior and senior staff members (11 (25%)), hesitance in speaking up (10 (23%)) and communication errors during teamwork (8 (18%)). The kappa values were 0.44–0.78. Unproceduralized communication and information exchange via telephone, related to transfer between units and consults from other specialties, were particularly vulnerable processes.

Conclusion

With the risk of bias in mind, it is concluded that more than half of the RCARs described erroneous verbal communication between staff members as root causes of or contributing factors of severe patient safety incidents. The RCARs rich descriptions of the incidents revealed the organisational factors and needs related to these errors.
Re-licensing of general practitioners using the current UK revalidation proposals: a cross sectional study
Authors: Charlton Rodger , Coomber J , Thistlethwaite J E
Published: October 2011

Objective

To explore the views of general practitioners (GPs) on the feasibility of collecting supporting information for the Royal College of General Practitioners (RCGP) revalidation portfolio and mapping of this evidence to the General Medical Practice framework for proposed UK medical re-licensing.

Design

Cross sectional study with a questionnaire.

Setting

One inner city and one mixed urban/rural primary care organisation in the West Midlands, England and one rural primary care organisation in Wales.

Participants

51/69 GPs who submitted a revalidation portfolio from November 2009 to February 2010.

Results

The majority of GPs considered the majority of work based supporting information was feasible to collect within a 5 year revalidation cycle; most concerns were expressed about providing evidence for extended practice, learning credits, and patient satisfaction and colleague feedback surveys (59%, 63%, 72%, and 77%, respectively, of GPs considered it feasible to collect this evidence) due to workload time constraints and lack of automatic access to evidence from others, which differed by GP work role. Two-thirds of participants (65%) stated that the submission of a portfolio of evidence was a feasible component of GP revalidation, reporting reservations on the appropriateness of patient and colleague feedback surveys and extended practice (55%, 57%, and 59% respectively) to provide objective evidence. GPs requested further clarity on the evidence mapping process.

Conclusion

Overall, GPs reported a positive response to the RCGP revalidation proposals. Concerns were focused on collecting the newer types of supporting information and the ability of GPs non-principals to collect this evidence. GP revalidation training and preparation is required.
ON THE THREE-DIMENSIONAL CONTAINER PACKING PROBLEM UNDER HOME DELIVERY SERVICE
Authors: LIU WAN-YU , LIN CHUN-CHENG , YU CHANG-SUNG
Published: November 2011

Home delivery service is one of the most important cost drivers in e-commerce industry. We consider the three-dimensional container packing problem under home delivery service, where each rectangular item with its specific destination is loaded orthogonally onto a rectangular container so that the utilization rate of the container space is maximized. In our framework, we assume the routing of a consignment to be given, which turns out that there is an order of unloading items with respect to the consignment. If we load items without considering the order of unloading items, we may unload and reload other unconcerned items drastically while unloading the required item. Therefore, in this paper, the unloading costs for a consignment are precisely defined according to the invisible and untouchable rule, and a subvolume scheme based algorithm is proposed. Our experimental results suggest our approach to be promising.
METRIC SPACES WITH SUBEXPONENTIAL ASYMPTOTIC DIMENSION GROWTH
Authors: OZAWA NARUTAKA
Published: October 2011

We prove that a metric space with subexponential asymptotic dimension growth has Yu's property A.
LOCAL MINIMIZERS WITH VORTEX PINNING FOR A GINZBURG–LANDAU FUNCTIONAL FOR SUPERCONDUCTING HOLLOW SPHERES
Authors: ZHAI JIAN , XUE SHUAI
Published: October 2011

In this paper, we consider the pinning effect for full Ginzburg–Landau functional on a superconducting hollow sphere. The existence of local minimizers with vortices locating in the pinning regions is obtained.
ON THE INTERPLAY OF REGULARITY AND DECAY IN CASE OF RADIAL FUNCTIONS I: INHOMOGENEOUS SPACES
Authors: SICKEL WINFRIED , SKRZYPCZAK LESZEK , VYBIRAL JAN
Published: October 2011

We deal with decay and boundedness properties of radial functions belonging to Besov and Lizorkin–Triebel spaces. In detail we investigate the surprising interplay of regularity and decay. Our tools are atomic decompositions in combination with trace theorems.
LONG-TIME BEHAVIOR OF SOLUTIONS TO NONLINEAR REACTION DIFFUSION EQUATIONS INVOLVING L1 DATA
Authors: ZHONG CHENGKUI , NIU WEISHENG
Published: October 2011

In this paper we consider the long-time behavior of solutions to nonlinear reaction diffusion equations involving L1 data, [Formula: see text] where Ω is a smooth bounded domain and u0, g ∈ L1(Ω). Using a decomposition technique combined with a bootstrap argument we establish some uniform regularity results on the solutions, by which we prove that the solution semigroup generated by the problem above possesses a global attractor [Formula: see text] in L1(Ω). Moreover, we obtain that the attractor is actually invariant, compact in [Formula: see text], q < max {N/(N-1), (2p-2)/p}, and attracts every bounded subset of L1(Ω) in the norm of [Formula: see text], 1 ≤ r < ∞.
Spectroscopic and theoretical insights on determination of binding strength and molecular structure for the supramolecular complexes of a designed bisporphyrin with C60 and C70
Authors: Mukherjee Partha , Chattopadhyay Subarata , Bhattacharya Sumanta
Published: October 2011

The present article examines the binding affinity of the newly designed Zn2-bisporphyrin molecule, syn-1, towards C60 and C70 in toluene medium. The investigation is carried out by UV-vis spectrophotometric, steady state and time-resolved fluorescence spectroscopic techniques. The bisporphyrin, syn-1, serves as an effective and selective molecular tweezer for C70 as average value of binding constants (K) for the non-covalent complexes of syn-1 with C60 and C70 are estimated to be 1.65 × 104 and 1.05 × 105 dm3 · mol-1, respectively. Binding of C70 in the cleft of syn-1 is clearly demonstrated by the quantum chemical calculations at ab initio level of theory. Molecular electrostatic potential maps demonstrate significant redistribution of charges in these supramolecules. Proton NMR studies suggest that the C70 moiety remains at the shallow part of the cleft of syn-1.
Synthesis and toxicity of cobaltabisdicarbollide-containing porphyrins of high boron content
Authors: Bhupathiraju N.V.S. Dinesh K. , Gottumukkala Vijay , Hao Erhong , Hu Xiaoke , Fronczek Frank R. , Baker David G. , Wakamatsu Nobuko , Vicente M. Graça H.
Published: October 2011

Two porphyrins of high boron content (OCP and HCP–PEG) were prepared in high yields from the reaction of the corresponding tri- and tetra-(dihydroxyphenyl)porphyrins with zwitterionic cobaltabisdicarbollide [3,3′-Co(8-C4H8O2-1,2-C2B9H10)(1′,2′-C2B9H11)] . Both porphyrins were found to have low cytotoxicity toward human HEp2 cells, and to localize subcellularly mainly in the cell lysosomes. Animal toxicity investigations using male and female BALB/c mice also revealed low toxicity for both compounds. The determined maximum tolerated dose (MTD) for these boronated porphyrins administered intraperitoneally were 160 mg/kg for OCP and 320 mg/kg for HCP–PEG. Our studies warrant further development of these porphyrins of high boron content, and in particular of HCP–PEG, as boron delivery vehicles for BNCT.
ASSESSING THE PRINCIPLES OF COMMUNITY-BASED NATURAL RESOURCES MANAGEMENT IN LOCAL ENVIRONMENTAL CONSERVATION PLANS
Authors: TANG ZHENGHONG , ZHAO NAN
Published: October 2011

Community-based natural resources management (CBNRM) is increasingly perceived as a bottom-up alternative approach to the traditional top-down rational model of local environmental conservation planning. Although many studies have discussed the effectiveness of these two models in environmental planning, little research has been done to empirically determine the influence of these two principles on local environmental conservation planning. This study analyses 54 cities' local environmental conservation plans to quantitatively measure the conceptual plan components, then uses regression models to detect the factors influencing local environmental conservation plan quality. Descriptive results indicate that local plans have a relatively low awareness of strategic-level conservation items, a medium level of analysis for regional conservation items, and a high level of community-based conservation efforts. Regression results further highlight that the governance capacity has significant influence on local environmental conservation plan quality; however, the community-based participation capacity was not statistically significant.
A NOVEL SIGNAL DECOMPOSITION APPROACH — ADAPTIVE FOURIER DECOMPOSITION
Authors: ZHANG LIMING , LI HONG
Published: October 2011

This paper presents a novel signal decomposition approach — adaptive Fourier decomposition (AFD), which decomposes a given signal based on its physical characters. The algorithm is described in detail, that is based on recent theoretical studies on analytic instantaneous frequencies and stands as a realizable variation of the greedy algorithm. The principle of the algorithm gives rise to fast convergence in terms of energy. Effectiveness of the algorithm is evaluated by comparison experiments with the classical Fourier decomposition (FD) algorithm. The results are promising.
AN EMPIRICAL STUDY OF TROPICAL CYCLONE ACTIVITY IN THE ATLANTIC AND PACIFIC OCEANS: 1851–2005
Authors: BAO S. , PIETRAFESA L. J. , HUANG NORDEN E. , WU Z. , DICKEY D. A. , GAYES P. T. , YAN T.
Published: October 2011

The trends and intrinsic frequencies in the time series of the number of Tropical Cyclones (TCs), hurricanes and typhoons, and Categories 4 and 5 hurricanes and typhoons in the Atlantic and Pacific Ocean domains, and the yearly integral of hurricane wind energy, represented by the Power Density Index (PDI), in the Atlantic and Eastern North Pacific Ocean domains are studied. The results show that the Empirical Modal Decomposition (EMD) method [Huang et al. (1998)] successfully reveals that there are intrinsic modes of variations that are controlled by climate systems such as the Quasi-Biennial Oscillation (QBO), the El Nino Southern Oscillation (ENSO), and the Atlantic and Pacific Multi-Decadal Oscillations (AMO and PDO), along with the Meridional Overturning Circulation (MOC). It also reveals some oscillation modes whose controlling factors are not yet identified. In both the Atlantic and Pacific Ocean domains, the frequencies of TCs, hurricane/typhoon-strength TCs and the strongest (Saffir-Simpson Categories 4 and 5) TCs have slowly rising trends. In the Atlantic Ocean, our study indicates that since the mid-1970s, the observed rise in the number of the strongest (Cats. 4 and 5) TCs as discussed previously by Webster et al. [2005] and the rise in the measure of destructiveness, the Power Density Index (PDI), developed by Emanuel [2005], were not the cause of rising trends, but instead, they are the result of the combination of positive phases of several intrinsic frequency modes. In the Pacific Ocean, the rising trends have larger amplitudes than those in the Atlantic Ocean, but the higher frequency modes appear to play a more important role in deciding the year-to-year Pacific TC, hurricane/typhoon and Cats. 4 and 5 TC activity levels.
Favorable Pathway of O2 Dissociative Adsorption on a Single Platinum Adatom Coated on Gamma-Alumina (111) Surface: A Density Functional Theory Study
Authors: Cahyanto Wahyu Tri , Oemry Ferensa , Padama Allan Abraham B. , Sakaue Mamoru , Belkada Rachid , Aspera Susan M. , Chikaishi Masahiro , Kunikata Shinichi , Nakanishi Hiroshi , Kasai Hideaki , Maekawa Hiroyoshi , Osumi Kazuo , Tashiro Yoshihisa
Published: October 2011

We have investigated the dissociative adsorption process of O2 (oxygen molecule) on a composite surface formed by coating a single platinum (Pt) adatom on a gamma-alumina (γ-Al2O3) (111) surface. This process is studied by using density functional theory (DFT) and described in terms of potential energy surfaces (PES) with respect to the molecular degrees of freedom. We compare the activation barriers and adsorption energies among typical reaction channels. Our results show that O2 dissociative adsorption is preferably occurred when this O2 molecule approaches the surface with molecular orientation inclined by 30° angle with respect to the surface normal, i.e., the condition with lowest activation barrier. The results indicate that dissociated O atoms are likely to form strong bonds with the Pt adatom by keeping distance from the alumina layer.
Non-Isothermal Crystallization in Amorphous GaxSe100-x Nanorods
Authors: Khan Zishan H.
Published: October 2011

Thermal properties of amorphous Ga
x
Se100-x
(a-Ga
x
Se100-x
) nanorods were studied at different heating rates (5, 10, 15, and 20 K/min) using differential scanning calorimetry. It has been observed that the values of glass transition temperature and crystallization temperature vary with composition and heating rate. The activation energy for structural relaxation (ΔE
t), the activation energy of crystallization (ΔE
c) and the order parameter (n) were calculated using the heating rate dependence of glass transition temperature and crystallization temperature. Several parameters such as thermal stability parameter (S), the crystallization enthalpy (ΔH
c), entropy (ΔS) changes during crystallization process and crystallization rate factor (K
p) were calculated to study the thermal stability of these glasses. Whereas the parameters such as Hruby number (H
R) and relaxation time (τ
T
g
) were estimated to understand the glass forming ability (GFA). The fragility index (F
i) for the present glasses was also calculated to ascertain whether these glasses were obtained from kinetically strong-glass-forming (KS) or kinetically fragile-glass forming (KF) liquids.
Dual Surface Discharge Mode for Improving Luminous Efficacy in AC Plasma Display Panel
Authors: Park Hyung Dal , Jang Soo-Kwang , Kim Jae Hyun , Tae Heung-Sik , Chien Sung-Il
Published: October 2011

In the current paper, we propose a new sustain waveform for dual light emission to improve the luminous efficiency of ac-plasma display panels (ac-PDPs). The proposed sustain waveform featuring dual discharge per sustain pulse has two rising steps, thus producing a second large discharge using the first small discharge generated in the first rising step. The resultant longer-sustained discharge can reduce power consumption without sacrificing luminance, thereby improving luminance efficiency by about 20%. Furthermore, the side ICCD image analysis reveals that owing to positive wall charges accumulating on the phosphor layer during the first small discharge, the ion incidence onto the phosphor layer can be suppressed during the second large discharge, thereby minimizing phosphor degradation during sustain discharge.
Reengineering Aircraft Structural Life Prediction Using a Digital Twin
Authors: Tuegel Eric J. , Ingraffea Anthony R. , Eason Thomas G. , Spottswood S. Michael
Published: October 2011

Reengineering of the aircraft structural life prediction process to fully exploit advances in very high performance digital computing is proposed. The proposed process utilizes an ultrahigh fidelity model of individual aircraft by tail number, a Digital Twin, to integrate computation of structural deflections and temperatures in response to flight conditions, with resulting local damage and material state evolution. A conceptual model of how the Digital Twin can be used for predicting the life of aircraft structure and assuring its structural integrity is presented. The technical challenges to developing and deploying a Digital Twin are discussed in detail.
Some Relations between Twisted (h, q)‐Euler Numbers with Weight α and q‐Bernstein Polynomials with Weight α
Authors: Jung N. S. , Lee H. Y. , Ryoo C. S.
Published: October 2011

By using fermionic p‐adic q‐integral on ℤp, we give some
interesting relationship between the twisted (h, q)‐Euler numbers with weight α and the
q‐Bernstein polynomials.
Massive Congenital Bidirectional Coronary Arteriovenous Malformation Presenting with Signs and Symptoms of Congestive Heart Failure in an Adult: A Case Report and Review of the Literature
Authors: Al Hashimi H. M. M. , Wardeh A. J. , Bulut S. , Verheugt F. W. A.
Published: October 2011

Congenital anomalies of the coronary arteries are relatively rare. Mostly asymptomatic, however, some can cause problems, as heart failure, myocardial ischemia, and ventricular arrhythmia, and are associated with risk of complications, such as endocarditis and coronary rupture or sudden death. A case of a 69-year-old man with complaints of tiredness, dyspnea, and palpitation due to coronary artery fistula is presented with a review of the literature.
Fascioliasis Control:In VivoandIn VitroPhytotherapy of Vector Snail to KillFasciolaLarva
Authors: Sunita Kumari , Singh D. K.
Published: October 2011

Snail is one of the important components of an aquatic ecosystem, it acts as intermediate host ofFasciolaspecies. Control of snail population below a certain threshold level is one of the important methods in the campaign to reduce the incidence of fascioliasis. Life cycle of the parasite can be interrupted by killing the snail orFasciolalarva redia and cercaria in the snail body.In vivoandin vitrotoxicity of the plant products and their active component such as citral, ferulic acid, umbelliferone, azadirachtin, and allicin against larva ofFasciolain infected snailLymnaea acuminatawere tested. Mortality of larvae were observed at 2 h, 4 h, 6 h, and 8 h, of treatment. Inin vivotreatment, azadirachtin caused highest mortality in redia and cercaria larva (8 h, LC500.11, and 0.05 mg/L) whereas inin vitrocondition allicin was highly toxic against redia and cercaria (8 h, LC500.01, and 0.009 mg/L). Toxicity of citral was lowest against redia and cercaria larva.
Lateral Information Processing by Spiking Neurons: A Theoretical Model of the Neural Correlate of Consciousness
Authors: Ebner Marc , Hameroff Stuart
Published: October 2011

Cognitive brain functions, for example, sensory perception, motor control and learning, are understood as computation by axonal-dendritic chemical synapses in networks of integrate-and-fire neurons. Cognitive brain functions may occur either consciously or nonconsciously (on “autopilot”). Conscious cognition is marked by gamma synchrony EEG, mediated largely by dendritic-dendritic gap junctions, sideways connections in input/integration layers. Gap-junction-connected neurons define a sub-network within a larger neural network. A theoretical model (the “conscious pilot”) suggests that as gap junctions open and close, a gamma-synchronized subnetwork, or zone moves through the brain as an executive agent, converting nonconscious “auto-pilot” cognition to consciousness, and enhancing computation by coherent processing and collective integration. In this study we implemented sideways “gap junctions” in a single-layer artificial neural network to perform figure/ground separation. The set of neurons connected through gap junctions form a reconfigurable resistive grid or sub-network zone. In the model, outgoing spikes are temporally integrated and spatially averaged using the fixed resistive grid set up by neurons of similar function which are connected through gap-junctions. This spatial average, essentially a feedback signal from the neuron's output, determines whether particular gap junctions between neurons will open or close. Neurons connected through open gap junctions synchronize their output spikes. We have tested our gap-junction-defined sub-network in a one-layer neural network on artificial retinal inputs using real-world images. Our system is able to perform figure/ground separation where the laterally connected sub-network of neurons represents a perceived object. Even though we only show results for visual stimuli, our approach should generalize to other modalities. The system demonstrates a moving sub-network zone of synchrony, within which the contents of perception are represented and contained. This mobile zone can be viewed as a model of the neural correlate of consciousness in the brain.
Numerical Polynomial Homotopy Continuation Method and String Vacua
Authors: Mehta Dhagash
Published: October 2011

Finding vacua for the four-dimensional effective theories for supergravity which descend from flux compactifications and analyzing them according to their stability is one of the central problems in string phenomenology. Except for some simple toy models, it is, however, difficult to find all the vacua analytically. Recently developed algorithmic methods based on symbolic computer algebra can be of great help in the more realistic models. However, they suffer from serious algorithmic complexities and are limited to small system sizes. In this paper, we review a numerical method called the numerical polynomial homotopy continuation (NPHC) method, first used in the areas of lattice field theories, which by construction findsallof the vacua of a given potential that is known to have only isolated solutions. The NPHC method is known to suffer from no major algorithmic complexities and isembarrassingly parallelizable, and hence its applicability goes way beyond the existing symbolic methods. We first solve a simple toy model as a warm-up example to demonstrate the NPHC method at work. We then show that all the vacua of a more complicated model of a compactified M theory model, which has anSU(3)structure, can be obtained by using a desktop machine in just about an hour, a feat which was reported to be prohibitively difficult by the existing symbolic methods. Finally, we compare the various technicalities between the two methods.
LMI‐Based Criterion for the Robust Stability of 2D Discrete State‐Delayed Systems Using Generalized Overflow Nonlinearities
Authors: Dey Anurita , Kar Haranath
Published: October 2011

This paper addresses the problem of global asymptotic stability of a class of discrete uncertain state‐delayed systems described by the Fornasini‐Marchesini second local state‐space (FMSLSS) model using generalized overflow nonlinearities. The uncertainties are assumed to be norm bounded. A computationally tractable, that is, linear‐matrix‐inequality‐(LMI‐) based new criterion for the global asymptotic stability of such system is proposed. It is demonstrated that several previously reported stability criteria for two‐dimensional (2D) systems are recovered from the presented approach as special cases. Numerical examples are given to illustrate the usefulness of the presented approach.
Emphysematous Cystitis: Report of an Atypical Case
Authors: De Baets Karen , Baert Joost , Coene Luc , Claessens Marc , Hente Robert , Tailly Geert
Published: October 2011

We report the atypical case of a nondiabetic 66-year old male with severe abdominal pain and vomiting who was found to have emphysematous cystitis. Of all gas-forming infections of the urinary tract emphysematous cystitis is the most common and the least severe. The major risk factors are diabetes mellitus and urinary tract obstruction. Most frequent causative pathogens areEscherichia coliandKlebsiella pneumoniae. The clinical presentation is nonspecific and ranges from asymptomatic urinary tract infection to urosepsis and septic shock. The diagnosis is made by abdominal imaging. Treatment consists of broad-spectrum antibiotics, bladder drainage, and management of the risk factors. Surgery is reserved for severe cases. Overall mortality rate of emphysematous cystitis is 7%. Immediate diagnosis and treatment is necessary because of the rapid progression to bladder necrosis, emphysematous pyelonephritis, urosepsis, and possibly fatal evolution.
A Population-Based Study of Peyronie's Disease: Prevalence and Treatment Patterns in the United States
Authors: DiBenedetti Dana Britt , Nguyen Dat , Zografos Laurie , Ziemiecki Ryan , Zhou Xiaolei
Published: October 2011

Purpose. To estimate the US prevalence of Peyronie's disease (PD) from patient-reported data and to identify diagnosis and treatment patterns.Methods. 11,420 US males ≥18 years old completed a brief web-based survey regarding the presence of PD, past treatments, and penile symptoms (Phase 1). Phase 1 respondents with PD diagnosis, history of treatment, or PD-related symptoms then completed a disease-specific survey (Phase 2).Results. Estimated prevalence of PD ranged from 0.5% (diagnosis of PD) to 13% (diagnosis, treatment, or penile symptoms). Thirty-six percent of Phase 2 participants reported that penile symptoms interfered with sexual activities. Of participants who sought treatment for penile symptoms (), 73% initially saw a primary care physician, 74% did not receive treatment from their first doctor, and 92% were not diagnosed with PD.Conclusions. PD may be underdiagnosed/undertreated in the US. Improved awareness is needed of PD symptoms and treatment options among health care professionals.
An Evaluation of Initial Vancomycin Dosing in Infants, Children, and Adolescents
Authors: Broome Laura , So Tsz-Yin
Published: October 2011

Background. The pharmacokinetics of many medications change as we age, thus most would assume dosing strategies would adjust for these changes. The objective of this study is to evaluate the initial vancomycin dosing in three pediatric age groups based on measured serum trough concentrations.Methodology. This retrospective database review included patients aged from 1 month to 18 years old admitted to the Moses H. Cone Memorial Hospital. Patients had to have received vancomycin dosed at 15 mg/kg every 8 hours with an appropriately measured trough concentration. The primary outcome was to determine the percentage of patients in 3 pediatric age groups achieving therapeutic trough concentrations with the initial vancomycin dosing regimen.Results. Twenty-five patients were included in the study. None of the patients had therapeutic trough concentrations after receiving vancomycin 15 mg/kg every 8 hours. Only one patient had a supratherapeutic level, while all of the other patients had levels less than 10 mcg/mL.Conclusions. Vancomycin 15 mg/kg every 8 hours did not provide therapeutic serum trough concentrations for any pediatric age groups. Higher doses and/or more frequent dosing regimens need to be evaluated for each age group to determine the most appropriate strategies for producing therapeutic trough concentrations.
Physical Activity: Exploring Views of Older Russian-Speaking Slavic Immigrants
Authors: Purath Janet , Van Son Catherine , Corbett Cynthia F.
Published: October 2011

Many of the 1.3 million Russian-speaking immigrants in the US have chronic conditions such as cardiovascular disease, diabetes, obesity, and depression. They engage in physical activity less often than other groups, and little is known about their views of physical activity. This qualitative study explored physical activity attitudes, beliefs, motivators, and barriers among older Russian-speaking immigrants. In four focus group interviews, 23 participants discussed physical activity. “Movement is life” was a theme throughout all interviews. Walking was the most frequently mentioned activity. Increased energy and decreased pain were described as health benefits. Motivators for physical activity were maintaining function, improved health, and the support of God and family. Barriers included poor health and environmental safety concerns. Participants suggested community walking groups and church-supported programs as useful methods to promote physical activity. Future research includes developing culturally appropriate interventions that utilize physical activity to prevent and manage chronic illness with ethnic minority older adults.