bluuebunny/crossref_metadata_2025_split huggingface dataset:
A gas chromatography/pyrolysis/isotope ratio mass spectrometry system for high‐precision δD measurements of atmospheric methane extracted from ice cores
Authors: Bock Michael , Schmitt Jochen , Behrens Melanie , Möller Lars , Schneider Robert , Sapart Celia , Fischer Hubertus 
Published: February 2010

AbstractAir enclosures in polar ice cores represent the only direct paleoatmospheric archive. Analysis of the entrapped air provides clues to the climate system of the past in decadal to centennial resolution. A wealth of information has been gained from measurements of concentrations of greenhouse gases; however, little is known about their isotopic composition. In particular, stable isotopologues (δD and δ13C) of methane (CH4) record valuable information on its global cycle as the different sources exhibit distinct carbon and hydrogen isotopic composition. However, CH4 isotope analysis is limited by the large sample size required and the demanding analysis as high precision is required. Here we present a highly automated, high‐precision online gas chromatography/pyrolysis/isotope ratio monitoring mass spectrometry (GC/P/irmMS) technique for the analysis of δD(CH4). It includes gas extraction from ice, preconcentration, gas chromatographic separation and pyrolysis of CH4 from roughly 500 g of ice with CH4 concentrations as low as 350 ppbv. Ice samples with approximately 40 mL air and only ∼1 nmol CH4 can be measured with a precision of 3.4‰. The precision for 65 mL air samples with recent atmospheric concentration is 1.5‰. The CH4 concentration can be obtained along with isotope data which is crucial for reporting ice core data on matched time scales and enables us to detect flaws in the measurement procedure. Custom‐made script‐based processing of MS raw and peak data enhance the system's performance with respect to stability, peak size dependency, hence precision and accuracy and last but not least time requirement. Copyright © 2010 John Wiley & Sons, Ltd.
ℋ︁∞sliding mode observers for uncertain nonlinear Lipschitz systems with fault estimation synthesis
Authors: Raoufi Reza , Marquez H. J. , Zinober A. S. I. 
Published: February 2010

AbstractThis paper presents a scheme to design robust sliding mode observers(SMO) with ℋ︁∞performance for uncertain nonlinear Lipschitz systems where both faults and disturbances are considered. We study the necessary conditions to achieve insensitivity of the proposed sliding mode observer to the unknown input(fault). The objective is to derive a sufficient condition using linear matrix inequality(LMI) optimization for minimizing the ℋ︁∞gain between the estimation error and disturbances, while at the same time the design method guarantees that the solution of the LMI optimization satisfies the so‐called structural matching condition. The sliding motion affects only a part of the system through a novel reduced‐order sliding mode controller. Furthermore, the so‐called equivalent control concept is discussed for fault estimation. Finally, a numerical example of MCK chaos demonstrates the high performance of the results compared with a pure SMO. Copyright © 2010 John Wiley & Sons, Ltd.
An efficient and secure agent code distribution service
Authors: Cucurull J. , Navarro‐Arribas G. , Martí R. , Robles S. , Borrell J. 
Published: February 2010

AbstractMobile agents (MAs) are autonomous computing entities that dwell in agent platforms and have the ability to move to different locations as needed. They are typically composed of code, data, and a state. The performance of MA migrations is always penalized by the need of carrying these components to each visited location. In contrast to the agent data and state, the agent code is static during the whole agent life. Therefore, optimizing the agent code management, the agent migration performance can be improved. The main contribution of this article is the definition of a global cache service to efficiently and securely deal with the distribution of agent code. An implementation of the service has been developed, and its benefits have been extensively demonstrated by a set of performance tests carried out in different scenarios. Copyright © 2010 John Wiley & Sons, Ltd.
Numerical Simulation of Liquid Steel Flow in Wedge‐type One‐strand Slab Tundish with a Subflux Turbulence Controller and an Argon Injection System
Authors: Cwudziński A. 
Published: February 2010

AbstractThe paper presents computational modelling of the liquid steel flow in a wedge‐type one‐strand slab tundish. The modelling was extended on the variance of liquid flow under a subflux turbulence controller (STC) and a gas permeable barrier on the tundish bottom. Commercial software was used for solving the mathematical model of the casting process. For the description of interactions between the continuous phase (liquid steel) and the discrete phase (inert gas), an Euler‐Lagrange description was chosen. The internal space of the subflux turbulence controller had the shape of a truncated cone, made according to a new design. Three locations for the gas permeable barrier were simulated and the flow rate of inert gas blown into the liquid steel was varied in the range from 10 to 30 Nl/min. The numerical modelling was validated by experimental tests which were carried out in an industrial wedge‐type tundish of a Polish steel plant. The industrial experiments included a direct sequence of heats of different chemical analysis in the course of the casting operation.The computations provided liquid steel flow maps, residence time distribution curves (RTD), and the volumes of particular flow types (stagnant, plug and ideal mixing flows), which characterize the effect of argon blowing and the subflux turbulence controller on liquid steel flow in the tundish. As a result, the industrial tundish operation was optimized.
Simulation of the Soaking and Gas Jet Cooling in a Continuous Annealing Line using Dilatometry
Authors: Granbom Y. , Ryde L. , Jeppsson J. 
Published: February 2010

AbstractThe present study concerns the simulation of a continuous annealing line (CAL), using dilatometry. Simulations of CAL have been performed on four commercial steel grades with different chemical compositions in order to investigate how the alloying elements C, Mn, Si and B affect the microstructure and hardness of dual phase (DP) and martensitic steels. Three annealing cycles corresponding to those used in a CAL have been applied. When annealing intercritically, as is the case in DP‐steel production, the materials do not reach equilibrium during soaking. Mn and C increase the austenite content and consequently the hardness of the materials. Higher levels of Si (0.4 wt %) are required to retard the formation of new ferrite during cooling in the gas jet section, prior to quenching. B increases hardenability effectively when annealing in the austenite region but is not as efficient during intercritical annealing, which implies that boron restrains ferrite nucleation rather than impeding ferrite growth. Results from DICTRA calculations show that it is possible to simulate the phase transformations during soaking, gasjet cooling and quenching.
Formation Free Energies of Solid Solution between Tri‐Calcium Phosphate and Di‐Calcium Silicate
Authors: Takeshita H. , Hasegawa M. , Kashiwaya Y. , Iwase M. 
Published: February 2010

AbstractIn order to determine the free energy changes for the reaction

molten copper containing phosphorus was brought into equilibrium with mixtures of tri‐calcium silicate + di‐calcium silicate + solid solution between tri‐calcium phosphate and di‐calcium silicate in a stream of Ar + H2 + H2O gas mixture at temperatures between 1548 and 1598 K, and the results are expressed as
Analysis of Mould, Spray and Radiation Zones of Continuous Billet Caster by Three‐dimensional Mathematical Model based on a Turbulent Fluid Flow
Authors: Shamsi M. R. R. I. , Ajmani S. K. 
Published: February 2010

AbstractAn analysis of mould, spray and radiation zones of a continuous billet caster has been done by a three‐dimensional turbulent fluid flow and heat transfer mathematical model. The aim was to reduce crack susceptibility of the billets and enhance productivity of the billet caster. Enthalpy‐porosity technique is used for the solidification. Turbulence is modelled by a realizable k‐ε model. The three‐dimensional mesh of the billet is generated by Gambit software, and Fluent software is used for the solution of equations. In various zones, different standard boundary conditions are applied. Enhanced wall treatment is used for the turbulence near the wall. In the mould region, Savage and Prichard expression for heat flux is applied. In the spray cooling zone, the heat transfer coefficient for surface cooling of the billet is calculated by knowing the water flow rate and the nozzle configuration of the plant. The model predicts the velocities in the molten pool of a billet, the temperature in the entire volume of billet, the heat transfer coefficient in the mould region, the heat flux in the cooling zone and radiation cooling zone, and the shell thickness at various zones. The model forecasts that the billet surface temperature up to the cutting region is above the austenite‐ferrite transformation temperature (which is accompanied by large volume change). The model predicts a temperature difference of maximum 700 K between the centre and surface of the billet. The entire solidification takes place at 11.0 m length at 3.0 m/min. For the same casting arrangement, increasing the casting speed up to 4.0 m/min has been explored. Based on the simulation results, recommendations to alter the spray water flow rate and spray nozzle diameter are presented to avoid a sudden change of temperature.
Inclusion Characteristics of Bearing Steel in a Runner after Ingot Casting
Authors: Doostmohammadi H. , Jönsson P.G. , Komenda J. , Hagman S. 
Published: February 2010

AbstractIn the uphill teaming method of ingot casting molten metal from the ladle goes into the runner system, which feeds one or several ingot moulds. This method is still important for production of bearing steel. In order to make clean steel, which has a controlled amount of inclusions, good understanding of inclusions characteristics is necessary. In this work non‐metallic inclusions of steel left in the runner part of an ingot casting system were studied. Inclusion type, size, and morphology were the main focus of this study. A scanning electron microscope (SEM) was used to assess inclusion size and morphology. The chemical composition of inclusions was determined by SEM equipped with EDS. An automated program called ‘INCAFeature’ was used to collect statistics of inclusion characteristics. Based on the statistical analysis of inclusion composition, four types of inclusions including oxides, sulfides, carbonitrides and complex inclusions were defined. The inclusion characteristics in the runner were also compared to literature data of inclusions found in ladle and mould samples.
Ermüdungsprobleme prismatischer, trogförmiger Eisenbahnbrücken mit dicken Tragblechen und deren Bewältigung
Authors: Schrade Christian 
Published: February 2010

AbstractBeim Nachweis prismatischer, trogförmiger Eisenbahnbrücken, die abgesehen von den Endquerträgern keine Aussteifungen aufweisen, ist die Annahme eines formtreuen Querschnitts nicht mehr grundsätzlich zulässig. Eine Untersuchung mit der Verallgemeinerten Technischen Biegetheorie (VTB) konnte zeigen, dass die erforderliche Ermüdungssicherheit für Bauwerke des untersuchten Typs bei Vernachlässigung von Querschnittsverformungen nicht unbedingt gegeben ist. Zur einfachen Bewältigung der Ermüdungsprobleme unter Berücksichtigung einer Vielzahl von Parametern wurde mit Microsoft Excel ein auf der VTB beruhendes Näherungsverfahren entwickelt, das die Querbiegespannungen sehr wirklichkeitsnah bestimmt. Es hat sich gezeigt, dass eine Erhöhung der Stegblechdicke, welche die Stahltonnage nur geringfügig anhebt, die Probleme löst, sodass die Vorteile des untersuchten Bauwerkstyps hinsichtlich Bauhöhe, Fertigung und Montage weiterhin bestehen.Fatigue problems of prismatic hutch‐shaped railroad bridges with thick plates and their handling. The assumption of a non deformable cross‐section at the calculation of prismatic hutchshaped railroad bridges without stiffening elements except for the bearing crossbeam is not in principle tolerable. An investigation with the Generalized Beam Theory (GBT) revealed that constructions of that kind due to high transverse bending do not necessarily achieve the sought fatigue security. In order to provide simple means for multiple choices of parameters, a GBT‐based approximation procedure, implemented in Microsoft Excel, was developed which calculates transverse bending stresses very accurately. It appeared that increasing the web plate thickness solves the problem, so that the advantages of the investigated bridge type concerning height of construction, assembly and installation persist.
Verallgemeinerte Technische Biegetheorie – Einordnung in die Entwicklungsgeschichte statischer Berechnungsmethoden
Authors: Strehl Christian 
Published: February 2010

AbstractSeit über 40 Jahren besteht ein logisches und erfolgreiches Berechnungsverfahren für Tragwerke aus zusammengesetzten Scheiben. Es stellt eine Erweiterung der technischen Biegelehre für die Berechnung biegesteifer prismatischer Faltwerke unter Berücksichtigung der Querschnittsverformungen dar. Die Entstehung der sogenannten Verallgemeinerten Technischen Biegetheorie (VTB) und die Leistungen dieses Berechnungsverfahrens werden hier anhand schematischer Skizzen erläutert.Generalized Beam Theory – A classification with respect to static calculation methods. Since more than 40 years a logical and successful method of analysis for structures combined of several plates exists. The method is an extension of the Engineer's Beam Theory for the calculation of rigid prismatic folded structures while allowing for changes of cross sections. The history of the so called Generalize Beam Theory (GBT) and the performance of this calculation method are illustrated by schematic diagrams.
Lagerungsbedingungen und Lagerkräfte in der Verallgemeinerten Technischen Biegelehre
Authors: Haakh Andreas 
Published: February 2010

AbstractDie Behandlung der Lagerungsbedingungen in der Verallgemeinerten Technischen Biegelehre (VTB) erfolgte seit ihrem Bestehen über die Zustandslager Längung, Biegungen, Torsion und den Profilverformungen. Lagerkräfte mussten aus den Schnittgrößendifferenzen rechts und links der Lager berechnet werden. In wurden erstmals diskrete Knotenlager in Form von Pendelstäben, Verschieblichkeiten und Festhaltungen eingeführt, allerdings ohne die Ermittlung der Lagerreaktionen. Nach einer kurzen Zusammenstellung der Grundlagen wird die systematische und einheitliche Behandlung allgemeiner Lagerbedingungen und ihre Rückrechnung mit Hilfe des Prinzip der virtuellen Verrückungen (P.d.v.V.) unter Verwendung des Weggrößenverfahrens dargestellt.Bearing conditions and bearing forces in the Generalized Beam‐Theory. The handling of bearing conditions in the Generalized Beam‐Theory (GBT) was realized by supporting modes such as elongation, bending, torsion and cross section distortions. Bearing forces had to be calculated using the difference of the internal forces on both sides of the support. In discrete node bearings like suspension rods, expansion bearings and fixed bearings were introduced, but without calculation of the bearing forces. After a short compilation of the basic principles a systematic and uniform handling of all bearing conditions and their calculation is presented using the principle of virtual displacements in conjunction with the displacement method.
Anwendung der Verallgemeinerten Technischen Biegetheorie in der Ingenieurpraxis
Authors: Schrade Wolfgang 
Published: February 2010

AbstractDie Zahl der wissenschaftlichen Publikationen und Fachbeiträge, die im Zusammenhang mit der Verallgemeinerten Technische Biegetheorie (VTB) stehen, dürfte, beginnend mit der Arbeit von Schardt im Jahr 1966, inzwischen die Zahl von fast 70 erreicht haben. Viele, wenn nicht sogar die meisten dieser Veröffentlichungen sind eher theoretischer Natur, so dass die Anwendung der VTB in der Ingenieurpraxis fast zwangsläufig etwas im Hintergrund bleibt. In dem nachfolgenden Beitrag soll deshalb anhand einiger ausgewählter Beispiele dargelegt werden, dass die Anwendung der VTB bei der Lösung entsprechender Aufgabenstellungen durchaus einer Behandlung zum Beispiel mit der FE‐Methode vorzuziehen ist.Application of the Generalized Beam Theory in practice. The number of scientific publications which are connected to the Generalized Beam Theory (GBT), beginning with Schardt's paper in 1966, should be about 70 right now. Most of these publications are rather theoretical so that the practical applicability of the GBT inevitably stays in the background. Therefore, the following essay by giving some examples is supposed to show, that in some practical cases the application of the GBT is to be preferred in comparison to the Finite Element Method.
Mit kühnem Schwung
Authors: Keil Andreas , Linden Sebastian 
Published: February 2010

AbstractIm Gelsenkirchener Norden, gleich hinter der ZOOM‐Erlebniswelt, überquert seit Juni 2009 eine filigrane, kreisförmig gekrümmte Hängebrücke den Rhein‐Herne‐Kanal. Mit einem kühnen Schwung und einer Spannweite von 141 m verbindet sie die Rad‐ und Wanderwege der südlichen Erzbahntrasse mit dem nördlichen Emscher Park Radweg. Die Brücke vereint durch ihre Leichtigkeit und ihre reduzierte, integrale Konstruktion ästhetische mit ingenieurmäßig sinnvollen Eigenschaften. Durch ungestützte Tragseilverankerungen und eine komplexe, dreidimensionale Werkstattform werden innovative Akzente gesetzt. Der vorliegende Bericht erläutert den Entwurf, die Planung und Ausführung sowie die komplexe Montage unter Schifffahrt dieser scheinbar schwebenden Konstruktion.With a bold sweep – A one‐side suspended pedestrian bridge in Gelsenkirchen, Germany. North of Gelsenkirchen, right behind ZOOM‐Erlebniswelt, a delicate, horizontally curved suspension bridge crosses the Rhine Herne Canal since June 2009. With a bold sweep and a span of 141 m it connects the bike and walking trails of the southern Erzbahntrasse with the northern Emscher Park bike trail. The bridge combines architectural aesthetic and discerning engineering attributes through its lightness and its minimal, integral construction. Using unsupported main cable anchorages and a complex, three‐dimensional workshop geometry, innovative accents were created. The following report illustrates the design, planning and construction as well as the complex erection sequence of this elegant, seemingly floating structure.
Development of capillary array DNA sequencers for genome analysis
Authors: Kambara H. 
Published: February 2010

AbstractMassive analysis of biological molecules is being successfully applied to elucidate various biological phenomena using techniques of molecular science. This new era was initiated by the Human Genome Project, which was supported by the development of various automated tools including DNA sequencers and DNA chips. A small project led by Akiyoshi Wada in Japan triggered the development of automated DNA analysis instruments. As one of the members of the project, the author has been engaged in developing DNA analyzers including capillary array DNA sequencers. Here, the principles and development of the main technologies related to capillary array DNA sequencers, which contributed to the completion of the Human Genome Project, are reviewed. © 2010 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 10: 000–000; 2010: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.200900010
A refined MAC protocol with multipacket reception for wireless networks
Authors: Lee Hyukjin , Lim Cheng‐Chew , Choi Jinho 
Published: February 2010

AbstractMedium access control (MAC) protocols making use of multipacket reception (MPR) capability achieve better throughput than conventional MAC protocols. When a wireless network operates with MPR capable nodes and non‐MPR nodes, the MAC protocols must not only utilise the MPR capability to maximise throughput, but must also enable the co‐existence with these two types of nodes. We propose a new MPR MAC protocol to achieve the co‐existence requirement by adopting a request‐to‐send (RTS)/clear‐to‐send (CTS) mechanism in IEEE 802.11 MAC standards. This MPR MAC protocol also improves throughput by allowing additional data transmissions to use the MPR capability fully. We analyse the system throughput of the co‐existence of different link characteristics of nodes, and optimise its throughput by adjusting contention window sizes with respect to certain throughput requirements of the nodes. Copyright © 2010 John Wiley & Sons, Ltd.
QoS provisioning for multiple non‐real‐time services in cellular wireless networks
Authors: Tzeng Show‐Shiow , Lu Hsin‐Yi 
Published: February 2010

AbstractFuture mobile services are expected to include various non‐voice oriented services. One important category of non‐voice oriented mobile services is non‐real‐time services. When a mobile user establishes a connection to access non‐real‐time service, the mobile user usually cares about whether the total time to complete its data transfer is within its time tolerance. In addition, different mobile users may have different bandwidth requirements and different tolerances in the total completion time. It is essential for wireless systems to provide various mobile users with different total completion times. In this paper, two quality‐of‐service (QoS) metrics, called stretch ratio and eligibility percentage, are employed at a connection level to present the degree of the length of the total completion time. We devise a measurement based call admission control scheme that provides multiple QoSs for various mobile users which have different requirements of stretch ratios, eligibility percentages, and bandwidths. Extensive simulation results show that the measurement based call admission control scheme not only provides various satisfactory QoSs for mobile users but also produces high throughput. Copyright © 2010 John Wiley & Sons, Ltd.
Determination method of optimal number of clusters for clustered wireless sensor networks
Authors: Li Wenfeng , Martins Philippe , Shen Lianfeng 
Published: February 2010

AbstractIn this paper, we present an analytical model for determining the optimal number of clusters, with the objective of minimizing the communication costs in a clustered wireless sensor network (WSN). Sensor nodes are located randomly and distributed according to a homogeneous two‐dimensional Poisson point process. Overall communication costs in the network are calculated analytically based on a practical energy consumption model at node level. The optimal probability of being a cluster head (CH) for each node is deduced by minimizing a cost function taking into account the energy dissipation of nodes. The scenarios with single‐hop and multi‐hop clustered networks are investigated. Simulation results show the existence of the optimum number of clusters which improves the energy efficiency of clustering schemes. We also verify by simulations that the analytical optimal probability of being a CH can provide a good approximation of the actual optimum probability, regardless of the different densities of nodes in the network. Copyright © 2010 John Wiley & Sons, Ltd.