bluuebunny/crossref_metadata_2025 huggingface dataset:
Systematic Review of Pretreatment Prostate-Specific Antigen Velocity and Doubling Time As Predictors for Prostate Cancer
Authors: Vickers Andrew J. , Savage Caroline , O'Brien M. Frank , Lilja Hans
Published: December 2008

Purpose

Pretreatment prostate-specific antigen (PSA) dynamics (PSA velocity and PSA doubling time) are widely advocated as useful prognostic markers in prostate cancer. We aimed to assess the published evidence for the clinical utility of PSA dynamics in this population.

Methods

We conducted a systematic review of studies published before March 2007 in which a PSA dynamic (velocity or doubling time) was calculated in patients before definitive treatment, a subsequent event (such as biopsy or recurrence) was ascertained, and the association between the two was analyzed. Our principal end point was the type of analysis reported, particularly whether the predictive accuracy of a statistical model that included both absolute PSA level and a PSA dynamic was compared with that of a model that included only PSA.

Results

Eighty-seven articles were eligible for analysis. The most common end points were biopsy (42 articles), and either recurrence (14 articles) or metastases or death (14 articles) after definitive therapy. Although PSA dynamics were generally found to be associated with outcome, only one article compared predictive accuracy of models with and without a PSA dynamic: this reported that PSA velocity improved prediction slightly (from 0.81 to 0.83), but was subject to verification bias. No article used decision analytic methods to examine the clinical impact of PSA dynamics.

Conclusion

There is little evidence that calculation of PSA velocity or doubling time in untreated patients provides predictive information beyond that provided by absolute PSA level alone. We see no justification for the use of PSA dynamics in clinical decision making before treatment in early-stage prostate cancer.
Residual strain analysis in polycrystalline aggregates using diffraction measurement and finite element modelling
Authors: Dini D , Song X , Zhang S Y , Korsunsky A M
Published: December 2008

This paper reviews some of the modelling and experimental techniques recently employed by the authors for the analysis of the macro- and mesoscopic behaviour of polycrystalline aggregates. A joined-up approach is used for assessing the deformation behaviour of polycrystalline materials at the macroscopic and grain levels, based on combining modelling using the crystal plasticity finite element (CPFE) method with experimental characterization by in situ loading and continuous lattice strain measurement by diffraction. The complementarity of the two methodologies is emphasized, as it helps to improve understanding of the physics underlying inelastic deformation, damage mechanisms, and fatigue crack initiation. The proposed approach is part of the attempt to develop a general framework that will enable reliable and accurate determination of the inhomogeneous fields of plastic strain, the regions of localized plasticity, and intergranular residual stresses. Examples are given of microscopically calibrated CPFE simulations being used to match the experimentally observed evolution of lattice stresses and strains in advanced structural alloys of industrial interest.
Electric strain gauge measurement of residual stress in welded panels
Authors: Ivetic G , Lanciotti A , Polese C
Published: December 2008

The current paper describes a destructive, sectioning method for measuring residual stress in welded panels, using electric strain gauges. Since this method is carried out rather simply, it has a wide range of possible applications. For this reason, a more thorough analysis of the method is performed. The potential limits of its application are investigated, together with the parameters that can influence the obtained results. The sectioning method is verified by determining residual stress in welded panels numerically. The results show it is possible to estimate the residual stress field in a welded structure rapidly and accurately, by using reasonably priced equipment.
Preliminary investigation on distribution of residual stress generated by the selective laser melting process
Authors: Casavola C , Campanelli S L , Pappalettere C
Published: December 2008

Selective laser melting (SLM) is one of the most interesting technologies used in rapid prototyping processes because of the possibility of building complex three-dimensional metal parts of nearly full density and with mechanical properties similar to those obtained with conventional manufacturing processes. This goal can be achieved using high-power lasers and low values of scan velocity. These conditions, together with an appropriate scanning strategy, allow full melting of the powders used in the process to be obtained.

The aim of this paper is to investigate the residual stresses in SLM specimens manufactured from AISI Marage 300 steel. First, the strain gauge hole drilling method is utilized to determine residual stress profiles in a set of test samples of different thicknesses, placed in different positions on the building platform. Statistical analyses are performed in order to study the relationships between sample position on the platform, the distance from the specimen surface, and maximum/minimum principal residual stresses. The experimental results show that the melting/solidification mechanism generates highly variable thermal residual stresses in the SLM parts used in this study.
Behaviour of three parallel non-symmetric mode III cracks in a functionally graded material plane
Authors: Zhang P-W , Zhou Z-G , Wu L-Z
Published: December 2008

In this article, the behaviour of three parallel non-symmetric finite-length cracks in an infinite functionally graded material plane subjected to anti-plane shear stress loading was studied by the Schmidt method. The problem was formulated through Fourier transform into three pairs of dual integral equations, in which unknown variables are the jumps of displacements across the crack surfaces. To solve the dual integral equations, the jumps of displacements across the crack surfaces were directly expanded as a series of Jacobi polynomials. The results show that the stress intensity factors depend on the crack lengths, spacing of cracks, and the material parameters. It was also revealed that the crack shielding effect is present in functionally graded materials.
Motion control of flexible-link manipulators
Authors: Kilicaslan S , Ider S K , Özgören M K
Published: December 2008

A new method is proposed for the end-effector trajectory tracking control of flexible robot manipulators. The equations of motion are separated into two parts that represent the pseudostatic equilibrium and the deviations from it. The part of the control input for the pseudostatic equilibrium is determined algebraically, and the other part of the control input for the stabilization of the deviations is obtained by a state variable feedback law, by using strain, joint variable, and end-effector position measurements. The feedback gain matrix is determined online by continuously updated pole placement. The pseudostatic equilibrium is defined here as a hypothetical state, in which the velocity and acceleration of the end-effector have their desired values whereas the elastic deformations are instantaneously constant. In order to demonstrate the method, a planar two-link robot with a flexible forearm is taken into consideration. The elasticity of the forearm is approximately described by the first two modes, and a controller is designed by using this two-mode model. Furthermore, in order to investigate the effects of modelling discrepancies, a ‘submodel controller’ is designed by using a model with only the first mode and it is applied to the same system with the two-mode model. The performances of these two controllers are compared by means of simulations. The behaviour of the flexible robot is also simulated by using the computed torque method as if the robot is rigid in order to illustrate the importance of including the flexibility effects in the formation of an appropriate control law. The spillover effect that causes the dominant poles to approach towards the imaginary axis is inspected by monitoring the real parts of the dominant poles of the closed-loop system under the effect of the ‘submodel’ and ‘computed torque’ controllers.
Investigation of flexible multi-mode harmonic vibration for the automatic washing process
Authors: Kuo J-L , Wang T-Y
Published: December 2008

This article discusses multi-mode vibration for the vibration motor in the washing process. Sinusoidal vibration modes for the speed servo command are carefully designed for flexible control. Different kinds of operating modes for possible automatic process control are provided. Three basic and five extended vibration modes for different operations are proposed. Simulation and experimental results will be compared to verify the formulation. To make the washing process more flexible, various servo commands are provided to be reconfigurable for the required vibration motion. Differing from the conventional approach of mechanically regulating the blade angle of the vibration motor, multi-mode vibration developed by the software approach is successfully proposed. It is easier for the washing process to be electrically regulated instead of it being a mechanical operation only. It is believed that this article will be beneficial for the application of an automatic washing process of the washing machine.
Frictional complete contacts subject to shear and bulk tension
Authors: Banerjee N , Dini D , Hills D A
Published: December 2008

This paper provides a set of ‘maps’ showing the response of three example frictional complete contacts (with edge angle of 60°, 90°, and 120°) subject to a constant normal load and the subsequent application of cyclic shear and bulk tension, the latter present in only one body. The maps define the region of full adhesion, the nature of violations, and conditions under which they arise.
An effective experimental method for identifying radiated noise of different angular ranges for the rolling-piston compressor
Authors: Huang Z , Jiang W , Zhang H , Liu C , Jin H , Zhou Y , He J
Published: December 2008

In the traditional analysis method of noise signals, it is very difficult to relate the overall noise from compressors to the angular position. The experimental method of separating the overall noise of different angular ranges is carried out at the real conditions. The starting position of the rotary piston is labelled with vane displacement and the test signals are synchronously sampled. Experimental results are analysed through fast Fourier transform method based on different angular ranges, which displays the following useful conclusions. The experiment technology could effectively identify the angular ranges for the frequency bands with prominent noise level; for the experimental rolling-piston compressor, the vibration, and sound pressure level of the discharge process (210–360 angular degrees) are the largest above the frequency 500 Hz. The discharge process is divided into three parts, where the final part contributes a little to the overall noise level when compared with the other two stages. Pressure pulsation is an important source of vibration and noise and its suppression of peak frequencies is the key of low-noise design of the compressor.
Experimental investigations for reducing wall thickness in zinc shell casting using three-dimensional printing
Authors: Kaplas M , Singh R
Published: December 2008

The purpose of this study is to verify the feasibility of decreasing the shell thickness in rapid casting (RC) process based on three-dimensional printing technology and to evaluate the dimensional accuracy, mechanical properties of RC solutions for the production of zinc-alloy casting. Starting from the identification of component/benchmark, technological prototypes were produced with different shell thickness. Measurements on a coordinate-measuring machine helped in calculating the dimensional tolerances of the castings produced. Some important mechanical properties were also compared to verify the suitability of the castings, and further results are supported by the radiography analysis. The study suggested that the shell thickness having value less than the recommended one is more suitable from dimensional accuracy and economic point of view. The provided data from the experimentation are extremely useful for the industrial application of the considered technology. The result indicates that at 7 mm shell thickness, hardness of the casting improved from the recommended 12 mm. Further, production cost and production time have been reduced by 41 and 37 per cent, respectively, in comparison with the 12 mm recommended shell thickness.
A simple and effective solution of the elastica problem
Authors: Campanile L F , Hasse A
Published: December 2008

The bending behaviour of thin stripes and leaf springs, in the presence of large deflections, is ruled by the so-called Bernoulli—Euler equation. The standard solution approach of this problem (‘elastica’) is represented by the non-linear finite-element analysis. In some special cases, closed-form solutions are available, which involve elliptic integrals and functions. In this article, an alternative method is presented based on the discretization of the deformed beam into circular-arc segments. The method is fast and simple to implement, and therefore suits well for the design and optimization of compliant kinematics.
Plastic behaviour of two-dimensional regular hexagonal structures with bilinear and uniaxial strength asymmetry in cellular materials
Authors: Zhang Qing Hang , Tan Soon Huat , Chou Siaw Meng
Published: December 2008

An elasto-plastic micromechanical model of the two-dimensional regular hexagonal structure was developed. General analytical expressions for the incremental constitutive relations were derived in terms of parameters defining the architecture and material of an internal beam. Non-linearity of the structure was introduced by considering the elastic—linear strain hardening behaviour of each internal beam, in which uniaxial strength asymmetry of the cellular material was accounted for. The plastic stress—strain relationship of the structure under any loading conditions can therefore be analysed by localized beam deformation. The results show that the bending deformation of the internal beam dominates under uniaxial stress loading conditions, however, the axial displacement dominates under the uniaxial strain conditions. The structure will present different behaviours under different loading conditions. The corresponding stresses under the uniaxial strain condition are greater than those under the uniaxial stress condition. The analyses also show that the volume fraction is highly correlated with the elastic constants and yield stresses of the structure. The denser the structure, the higher the moduli and yield stresses.
An experimental semi-active anti-roll system
Authors: Stone E J , Cebon D
Published: December 2008

The use of anti-roll bars to provide additional roll stiffness and therefore to reduce the trade-off between ride and rollover performance has previously been studied. However, little work has been carried out to investigate the benefits of a switchable roll stiffness. Such a semi-active anti-roll system has the ability to have a low roll stiffness during straight-ahead driving for improved ride performance and high roll stiffness during cornering for improved roll performance.

Modelling of such a system is conducted and the model is validated against a semi-active anti-roll system fitted to an experimental vehicle. Experimental and theoretical investigations are used to investigate the performance of such a system with several different strategies employed to switch to the high-stiffness state. The use of an air suspension on the vehicle to roll into corners is also investigated, as is the possibility of exploiting the road layout by allowing the vehicle to be in a low-roll-stiffness configuration during a corner, and then to switch to the high-roll-stiffness configuration midcorner, hence ‘locking in’ a roll angle. The best rollover performance improvement that was achieved was 12.5 per cent.
Research on elastohydrodynamic lubrication of a crankshaft bearing with a rough surface considering crankshaft deformation
Authors: Sun J , Gui C-L , Wang Z-H
Published: December 2008

Journal misalignment in bearings caused by crankshaft deformation under load exists generally in internal combustion engines. When serious journal misalignment takes place, the minimum oil-film thickness of bearings is greatly reduced and the maximum oil-film pressure of the bearings increases markedly. Therefore, it is necessary to consider the surface roughness and deformation of bearing surface when analysing the hydrodynamic lubrication characteristics of a misaligned bearing. In this paper, the elastohydrodynamic lubrication properties of crankshaft bearings considering crankshaft deformation under load and the surface roughness for a four-cylinder internal combustion engine were studied. The lubrications of the crankshaft bearings were analysed by the dynamic method. The deformation of the bush surface under the oil-film pressure was calculated by the deformation matrix method. The results show that, when crankshaft deformation is considered, the surface roughness has a marked effect on the orbits of the crankshaft bearings, but deformation of the bearing surface scarcely affects the orbits of the crankshaft bearings. When the surface roughness of a bearing is considered, the maximum oil-film pressure of crankshaft bearings obviously increases, the minimum oil-film thickness decreases markedly, and the end flowrate changes little in most of the engine cycle. When elastic deformation of the bearing surface is considered, the maximum oil-film pressure of bearings decreases to a different extent: elastic deformation of the bearing surface affects the end flowrate, the frictional coefficient of the journal, and the minimum oil-film thickness very little.
Impact of thermal barrier coating application on the performance and emissions of a turbocharged diesel engine
Authors: Ciniviz M , Hasimoglu C , Şahin F , Salman M S
Published: December 2008

In this study, the effect of thermal-barrier-coated piston top and combustion chamber surfaces on turbocharged diesel engine performance was experimentally investigated. Satisfactory performance was obtained with TBC1 (with coated cylinder head and valves) and TBC2 (with coated cylinder head, piston top, and valves). Compared with a standard diesel engine, engine power was increased by 2 per cent, the engine torque was increased by 1.5–2.5 per cent, and brake specific fuel consumption (b.s.f.c.) was decreased by 4.5–9 per cent. The NO x emissions were increased by 10 per cent in diesel engines with TBC coatings compared with a standard diesel engine. Experimental studies have shown that there is a reduction in smoke emissions of up to 18 per cent as a result of TBC application.
A comparison of three steering controllers for off-road vehicles
Authors: Gao Y-J , Huang R , Zhang Q
Published: December 2008

Many off-road vehicles use electrohydraulic (E/H) actuators for implementing steering controls. However, the high non-linearity of E/H steering systems often results in difficulties in achieving high performance in steering control, especially when it requires only some small steering corrections. Such features of E/H steering systems call for capable control methods to overcome the non-linearity problems in achieving a desirable level of steering performance. This paper presents a comparison of the performance of three commonly used controllers, namely a proportional—integral—derivative (PID) controller, a feedforward-plus-PID (FPID) controller, and a fuzzy controller, for an E/H steering system. To isolate environment influences on the investigation of the controller performance, the comparison tests were implemented on a validated hardware-in-the-loop (HIL) E/H steering system simulator. The results obtained confirmed that both the FPID and fuzzy controllers have superior performance in compensating for system deadband and could achieve more sensitive and accurate small steering corrections than a PID controller.
Fatigue life analysis of the autobody in a sports utility vehicle and its improvement using the homogenization method
Authors: Ping Z , Jun H , Jin M
Published: December 2008

Fatigue life analysis and improvement of the autobody in a sports utility vehicle (SUV) were performed. The stress distribution under unit displacement excitation was obtained by the finite element (FE) method. A bilateral track model was adopted to obtain load spectra in accordance with the vehicle reliability test. The total life of the autobody was evaluated by the nominal stress method with the assumption of a uniaxial stress state, and thus the critical regions were determined. The life of components with critical regions was further investigated on the basis of multiaxial fatigue theory. The results show that some components near to the suspension are easy to damage because they are directly subjected to impact loading from the road. It is also indicated that the result from multiaxial fatigue analysis is more reasonable than that from the nominal stress method, which was verified by experimental results. Finally, topological optimization of the spot weld location in the critical region was carried out by the homogenization method to improve its fatigue life.
Management of angular speed sensors for control at the power-zero condition of a continuously variable transmission: A describing-function approach
Authors: Codecà F , Tanelli M , Savaresi S M , Frignati D , Taroni F , Tascedda L
Published: December 2008

This paper focuses on the control at the power-zero condition of a power-split continuously variable transmission (CVT) used in agricultural tractors. The power-zero condition requires the controller to regulate the transmission ratio to zero, independently of the input engine speed. This is particularly useful when the tractor is operated uphill or downhill, in order to keep the vehicle still without using brakes. As the considered CVT is tailored to low-power tractors used in orchards and vineyards, this is indeed a very important functioning mode. Specifically, it is shown how the control problem is deeply interleaved with the choice of the appropriate angular speed sensors used for computing the transmission ratio and the algorithm used to process their output for computing the angular speed. An innovative analysis on the estimation error and the time delay of the two main speed estimation algorithms is developed. In particular, it is proven that the delay introduced by the speed sensor can cause an undesired limit-cycle behaviour in the closed-loop system. The existence and stability properties of such a limit cycle are assessed with a describing-function approach, and a strategy to suppress the limit cycle is proposed.
Sliding mode control for torque ripple reduction of an electric power steering system based on a reference model
Authors: Li X , Zhao X-P , Chen J
Published: December 2008

Torque ripple in an electric power steering (EPS) system can be induced by the phase lag between steer angle and rack displacement, non-linear friction, and disturbances from road and sensor noise, especially during high-frequency manoeuvres. This paper investigates the application of robust and non-linear sliding mode control (SMC) strategies to an EPS system, based on a reference model to reduce the torque ripple and stabilize the dynamics of the EPS system. The dynamics of the EPS system is described by a non-linear state-space model with realistic non-linear friction and disturbances from road and sensor noise. Meanwhile, the ideal EPS system, in which the rack displacement tracks the steer angle perfectly, is proposed as the reference model. A non-linear sliding mode observer (SMO) is also developed to estimate the unmeasurable states. The performance and robustness of SMC and SMO are demonstrated using various simulations and compared with traditional alternatives. The results of these simulations reveal that the non-linear SMC and SMO strategies can reduce the torque ripple to achieve a better steering feel and more stable driving, and can be applied to commercial EPS systems.
Simulation of planetary gear trains, modelling and numerical validation
Authors: Cervantes-Sánchez J J , Rico-Martínez J M , Ledesma-Jaime R , Barroso-Hernández J L
Published: December 2008

This article introduces a novel set of multi-bond graph diagrams (MBGDs), which are intended for modelling an arbitrary planetary gear train (PGT). In this regard, three standard MBGDs are proposed: (a) one was developed for representing a single moving body, (b) another was designed for describing a revolute joint, and (c) the last one was created for representing a gear pair. Thus, by taking advantage of the module handling facility offered by the multibond graph technique (MBGT) and by adopting a multi-body-based approach, such models can be systematically coupled, through an assembling procedure, thereby forming the complete model for the whole PGT. Moreover, the obtained model incorporates both kinematics and kinetics equations of the PGT under study and allows us to perform a comprehensive power-flow analysis. The proposed approach also offers the capability of computing the dynamic loads of bearings and gear teeth for an adequate design of the PGT at hand. Furthermore, the resulting MBGD of the PGT has assigned an integral causality, which is a salient feature to be pursued in the resulting set of state equations, and mathematically means that an explicit set of first-order, differential equations can be obtained. Finally, the proposed diagrams are numerically validated by means of the simulation of a typical PGT and by its corresponding comparison with the Lagrange's equations and also with the Euler's laws.
Complete shaking force and shaking moment balancing of planar parallel manipulators with prismatic pairs
Authors: Briot S , Bonev I A , Gosselin C M , Arakelian V
Published: December 2008

This article deals with the complete shaking force and shaking moment balancing of planar parallel manipulators with prismatic pairs. The cancellation of dynamic loads transmitted to the ground is a challenge for these types of manipulators.

It is obvious that the classical methods based on the optimal redistribution of movable masses and additional counter-rotations can be used to cancel shaking force and shaking moment. However, balancing of parallel manipulators with prismatic pairs is attained via a considerably complicated design. This article shows that it is possible to balance planar parallel mechanisms by using Scott—Russell mechanisms. Such an approach enables counter-rotations to be divided by 2. Numerical simulations carried out using ADAMS software validate the obtained results and illustrate that the suggested balancing enables to create a parallel manipulator transmitting no inertial load to its base.
Adhesively bonded joints in composite materials: An overview
Authors: Banea M D , da Silva L F M
Published: December 2008

A review of the investigations that have been made on adhesively bonded joints of fibre-reinforced plastic (FRP) composite structures (single skin and sandwich construction) is presented. The effects of surface preparation, joint configuration, adhesive properties, and environmental factors on the joint behaviour are described briefly for adhesively bonded FRP composite structures. The analytical and numerical methods of stress analysis required before failure prediction are discussed. The numerical approaches cover both linear and non-linear models. Several methods that have been used to predict failure in bonded joints are described. There is no general agreement about the method that should be used to predict failure since the failure strength and modes are different according to the various bonding methods and parameters, but progressive damage models are quite promising since important aspects of the joint behaviour can be modelled by using this approach. However, a lack of reliable failure criteria still exists, limiting in this way a more widespread application of adhesively bonded joints in principal load-bearing structural applications. An accurate strength prediction of the adhesively bonded joints is essential to decrease the amount of expensive testing at the design stage.
Friction stir processing: Thermo-mechanical loads and consequent effects on the local material characteristics
Authors: Fratini L
Published: December 2008

The present article is focused on the correlation between the applied thermal and mechanical loads and the consequent effects on the material in friction stir processing (FSP) operations. On one hand, the actions exerted in FSP are split compared to the results obtained with a tool without the pin at its end to a traditional one with a cylindrical pin. In this way, the thermal flux determined by the frictional forces at the tool—shoulder—workpiece interface is secluded from the mechanical stirring action made by the tool pin. On the other hand, the processed specimens are analysed in terms of residual stress state, microhardness, and average grain size values. An in-process heat treatment of the processed blanks was also carried out to highlight the single local actions and effects on the material. The obtained results permit to determine cause—effect correlations between the considered inputs and outputs. AA7075-T6 aluminium blanks were used for the study.
MCrAlY creep behaviour modelling by means of finite-element unit cells and self-consistent constitutive equations
Authors: Hermosilla U , Karunaratne M S A , Jones I A , Hyde T H , Thomson R C
Published: December 2008

The MCrAlY bond coats (BCs) used in thermal barrier coatings (TBCs) undergo severe microstructural changes that affect their creep behaviour. One method to take into account the effect of the high-temperature degradation in the creep properties of these alloys is by means of unit cell calculations that reproduce the microstructure present in the alloy. However, this method is not suitable to be included in large-scale calculations and a self-consistent constitutive model, based on Eshelby's inclusion technique, is presented for that purpose, showing good numerical agreement. Results are compared with experimental data obtained for several MCrAlY BCs.
Generalized methodology for operational risk analysis of offshore installations
Authors: Vinnem J E , Seljelid J , Haugen S , Sklet S , Aven T
Published: December 2008

The barrier and operational risk analysis (BORA) project has developed a model for risk analysis based on the use of event trees, fault trees, influence diagrams, and risk influencing factors (RIFs). The model has been applied in some case studies in the project. The experience from these case studies has been used to develop a generalized methodology for analysis of operational barriers that are intended to prevent hydrocarbon leaks. A stepwise description of this generalized methodology is presented and discussed in the paper.
A rule-based approach for establishing states in a Markov process applied to maintenance modelling
Authors: Welte T M
Published: December 2008

The deterioration of technical systems can often be classified into discrete states, and the transitions between these states can be modelled using a Markov process. Instead of using an exponential distribution, it may be more realistic to assume that a general probability distribution describes the sojourn time in one of these states. The resultant model is a semi-Markov process, which may be difficult to treat analytically. This paper therefore presents an approach where the sojourn times in these states are gamma distributed and where the gamma distribution is transformed into a Markov process with a sequence of states that have exponentially distributed sojourn times. This means that the gamma distribution is approximated by a Markov process, which simplifies maintenance modelling. The approach presented is based on a simple rule such that it can easily be implemented in a maintenance model. It is shown that the approach yields good results compared with available alternatives.
Identification of stochastic and deterministic stochastic Petri net models for reliability analysis
Authors: Ould El Medhi A , Leclercq E , Lefebvre Greah D
Published: December 2008

Reliability analysis for dynamical systems is often based on timed stochastic Petri net (PN) models. A priori knowledge about failure processes is difficult to obtain and, as a consequence, the model structure and parameters are mainly unknown. In that case, synthesis and identification methods based on analysis of collected event sequences are of great interest. The contribution of this paper concerns the identification of timed stochastic PN models. Stochastic and deterministic stochastic PNs with deterministic and exponentially distributed transition durations are considered. A systematic identification method is proposed according to event sequences that are recorded by supervision systems. This method is based on the idea that the dynamic behaviour of considered PN can be mapped into a Markov model with state space isomorphic to the reachability graph of the untimed PN model.
Diagnosis and fault signature analysis of a wind turbine at a variable speed
Authors: Bennouna O , Héraud N , Camblong H , Rodriguez M , Kahyeh M A
Published: December 2008

The diagnosis of dynamic linear systems has been studied in a previous paper by using the polynomial representation of each variable. Data validation and gross error detection were investigated. This paper uses fault signature analysis to detect errors in the doubly fed induction generator (DFIG) of a wind turbine. The major contribution of this paper is that the wind turbine is operating at variable speed.
Multiplatform phased mission reliability modelling for mission planning
Authors: Prescott D R , Andrews J D , Downes C G
Published: December 2008

Autonomous systems are being increasingly used in many areas. A significant example is unmanned aerial vehicles (UAVs), regularly being called upon to perform tasks in the military theatre. Autonomous systems can work alone or be called upon to work collaboratively towards common mission objectives. In this case it will be necessary to ensure that the decisions enable the progression of the platform objectives and also the overall mission objectives.

The motivation behind the work presented in this paper is the need to be able to predict the failure probability of missions performed by a number of autonomous systems working together. Such mission prognoses can assist the mission planning process in autonomous systems when conditions change, with reconfiguration taking place if the probability of mission failure becomes unacceptably high.

In a multiplatform phased mission a number of platforms perform their own phased mission that contributes to an overall mission objective. Presented in this paper is a methodology for calculating the phase failure probabilities of a multiplatform phased mission. These probabilities are then used to find the total mission failure probability. Prior to the mission the failure probabilities are used to decide if the original mission structure is acceptable. Once underway, failure probabilities, updated as circumstances change, are used to decide whether a mission should continue. Circumstances can change owing to failures on a platform, changing environmental conditions (weather), or the occurrence of unforeseen external events (emerging threats). This diagnostics information should be used to ensure that the updated failure probabilities calculated take into account the most up-to-date system information possible. Since the speed of decision making and the accuracy of the information used are essential, binary decision diagrams (BDDs) are utilized to form the basis of a fast, accurate quantification process.
Reliability assessment of a wind power delivery system
Authors: Karki R , Patel J
Published: December 2008

Growing environmental concerns have led to renewable energy policies, such as the renewable portfolio standard, that have set ambitious targets for wind power penetration in electric power systems throughout the world. In many cases, the geographical locations with good wind resources are not close to the main load centres. Wind is a highly variable energy source and, therefore, transmission system planning for wind delivery is very different from conventional transmission planning. It becomes extremely important to assess the availability of wind power against the cost of transmission facility connecting to the power grid. This paper presents an analytical method to determine appropriate transmission line sizing based on its contribution to the overall system risk. The studies can also be used to evaluate the reliability contribution of the combined wind generation and transmission systems. The effects of generation, transmission, and load parameters on risk-based transmission line sizing are presented using a test system. The methodology and results presented in this paper should be useful in wind site selection and transmission system planning for delivering wind power.
The roots of human altruism
Authors: Warneken Felix , Tomasello Michael
Published: December 2008

Human infants as young as 14 to 18 months of age help others attain their goals, for example, by helping them to fetch out‐of‐reach objects or opening cabinets for them. They do this irrespective of any reward from adults (indeed external rewards undermine the tendency), and very likely with no concern for such things as reciprocation and reputation, which serve to maintain altruism in older children and adults. Humans' nearest primate relatives, chimpanzees, also help others instrumentally without concrete rewards. These results suggest that human infants are naturally altruistic, and as ontogeny proceeds and they must deal more independently with a wider range of social contexts, socialization and feedback from social interactions with others become important mediators of these initial altruistic tendencies.
Embodied ideas and divided selves: Revisiting Laing via Bakhtin
Authors: Burkitt Ian , Sullivan Paul
Published: December 2008

In this article, we apply Mikhail Bakhtin's model of a ‘divided self’ to R.D. Laing's eponymous work on the lived experience of divided selves in ‘psychosis’. Both of these authors offer intriguing insights into the fracturing of self through its social relationships (including the ‘micro‐dialogues’ staged for oneself) but from uniquely different perspectives.Bakhtin (1984)uses Dostoevsky's novels as his material for a theory of self, centrally concerned with moments of split identity, crisis, and personal transformation, while Laing relies on his patient's accounts of ‘psychosis’. We will outline how two key Bakhtinian divisions of the self (spirit/soul and authoritative/internally persuasive discourse) help to make sense of Laing's descriptions of his patient's experiences and micro‐dialogues. Conversely, when refracted through Laing's phenomenology Bakhtin's account of the self becomes richer and somewhat darkened in terms of a double‐edged ontology, which describes a maximally open self but one that is consumed by ideas, unable to manage their contradictions. The implications of this for managing the dilemmas of self‐identity will be drawn out.
Imaging of metals and metal-containing species in biological tissues and on gels by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS): A new analytical strategy for applications in life sciences
Authors: Becker J. Sabine , Zoriy M. , Dressler Valderi L. , Wu Bei , Becker J. Susanne
Published: December 2008

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has become established as a very efficient and sensitive trace, ultratrace, and surface analytical technique in the life sciences. We have developed a new analytical imaging technique using LA-ICP-MS to study element distribution in biological tissues. Nowadays, LA imaging ICP-MS using double-focusing sector field (LA-ICP-SFMS) or quadrupole-based mass spectrometers (LA-ICP-QMS) can be applied as an exciting tool providing new information on the pathophysiology, pharmacology, and toxicology of elements of interest in biological systems. The quantitative determination of elements (e.g., Cu, Fe, Zn, Se, and others) in biological tissues is of growing interest especially in brain research (e.g., for studying neurodegenerative diseases such as Alzheimer's or Parkinson's disease). LA-ICP-SFMS was employed to produce images of detailed regionally specific element distributions in thin tissue sections of different sizes (such as control human or rat brain tissues or tumor regions). In addition, imaging MS using LA-ICP-QMS was applied to study the uptake and transport of nutrient and toxic elements in plant tissues.

Besides the quantitative imaging of essential and toxic elements in tissues, powerful analytical techniques are also required for the determination and characterization of phosphoproteins and metal-containing proteins within a large pool of proteins, after electrophoretic separation (e.g., blue native, BN and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, SDS-PAGE) into 1D and 2D gels. LA-ICP-MS was used to detect metalloproteins in protein bands of 1D gels or protein spots separated after 2D gel electrophoresis (2D-GE). In addition to elemental determination by LA-ICP-MS, matrix-assisted laser desorption/ionization (MALDI)-MS was employed to identify metal-containing proteins. Recent progress will be discussed in applying LA-ICP-MS in the life sciences, including the imaging of thin slices of tissue and applications in proteome analysis in combination with MALDI-MS to investigate phosphoproteins and metal-containing proteins.
Structural chemistry involved in information detection and transmission by gas sensor heme proteins: Resonance Raman investigation
Authors: El-Mashtoly Samir F. , Kitagawa Teizo
Published: December 2008

A variety of heme-containing gas sensor proteins have been discovered by gene analysis from bacteria to mammals. In general, these proteins are composed of an N-terminal heme-containing sensor domain and a C-terminal catalytic domain. Binding of O2, CO, or NO to the heme causes a change in the structure of heme, which alters the protein conformation in the vicinity of the heme, and the conformational change is propagated to the catalytic domain, leading to regulation of the protein activity. This mini-review summarizes the recent resonance Raman studies obtained with both visible and UV excitation sources for two O2 sensor proteins, EcDOS and HemAT-Bs. These investigations have shown the role of heme propionate hydrogen-bonding interactions in communicating the heme structural changes, which occur upon ligand binding, from heme to the protein moiety. Furthermore, it is deduced that the contact interactions between the heme 2-vinyl group and the surrounding residues are also important for signal transmission from heme to protein in EcDOS.
Specific transporter for iron(III): Phytosiderophore complex involved in iron uptake by barley roots
Authors: Murata Yoshiko , Harada Emiko , Sugase Kenji , Namba Kosuke , Horikawa Manabu , Ma Jian Feng , Yamaji Naoki , Ueno Daisei , Nomoto Kyosuke , Iwashita Takashi , Kusumoto Shoichi
Published: December 2008

Iron (Fe) is an essential element for plant growth. Gramineous plants have generally developed a distinct strategy to efficiently acquire insoluble Fe, which is characterized by the synthesis and secretion of an Fe-chelating substance, phytosiderophore (PS) such as mugineic acid (MA), and by a specific uptake system for Fe(III)-PS complexes. In a previous study, we identified a gene specifically encoding an Fe(III)-PS transporter (HvYS1) in barley. This gene as well as the encoded protein is specifically expressed in the epidermal cells of the roots, and gene expression is greatly enhanced under Fe-deficient conditions. The localization and substrate specificity of HvYS1 indicate that it is a specific transporter in barley roots. In contrast, ZmYS1, which has been reported as an Fe-PS transporter from maize, possesses broad substrate specificity despite a high homology with HvYS1. By assessing the transport activity of a series of HvYS1-ZmYS1 chimeras, we revealed that the outer membrane loop between the 6th and 7th transmembrane regions is essential for the substrate specificity. We also achieved an efficient short-step synthesis of MA and 2'-deoxymugineic acid (DMA). Our new synthetic method enabled us to use them in a large quantity for biological studies.
Action mechanism of metallo-allixin complexes as antidiabetic agents
Authors: Hiromura Makoto , Sakurai Hiromu
Published: December 2008

The metabolic syndrome is a group of factors associated with an increased risk of atherosclerosis and diabetes. Diabetes mellitus (DM) is classified into 2 major types - type 1 DM and type 2 DM - characterized by chronic hyperglycemia resulting from defects in insulin secretion and insulin action, respectively. Several synthetic pharmaceuticals have been developed and clinically used for treating DM; however, these pharmaceuticals continue to cause side effects. Recently, we proposed that oxovanadium(IV) (vanadyl) and zinc(II) (zinc) complexes are potent antidiabetic agents for both type 1 and type 2 DM therapy. This article reviews the vanadyl- and zinc-allixin and their related complexes that are being currently developed as novel types of antidiabetic metal complexes, focusing on their action mechanism in terms of regulation of the insulin signaling pathway and inhibition of lipolysis signaling in adipocyte cells.
Expression of Immunoglobulin Gene With Classical V-(D)-J Rearrangement in Mouse Testis and Epididymis
Authors: Huang Jing , Zhang Li , Ma Teng , Zhang Pei , Qiu Xiaoyan
Published: December 2008

Immunoglobulin (Ig) molecules have thus far been found only to be produced by differentiated B lymphocytes. As we know, immune privilege in the normal adult mouse testis exists to make these privileged sites generally free of patrolling immune cells and Igs. However, in this study, the expression of Ig in normal adult mouse testis and epididymis was detected. First, by IHC, a strong pattern of Ig expression was detected in the spermatogenic cells of adult mouse testis at different development stages. Second, by Western blot analysis, different strong bands of Igs in mouse testicular spermatogenic cells and epididymal epithelial cell extract were recognized using specific antibodies against IgG. More importantly, by ISH and cell sorting–related RT-PCR, rearranged Ig γ chain and κ chain transcripts were expressed in testicular spermatogenic cells and epididymal epithelial cells. These results suggested that Ig in testis and epididymis was mainly produced by adult mouse testicular spermatogenic cells and epididymal epithelial cells. This manuscript contains online supplemental material at http://www.jhc.org. Please visit this article online to view these materials.