bluuebunny/crossref_metadata_2025_split huggingface dataset:
Parental Relationships and Behavioral Approach System Dysregulation in Young Adults With Bipolar Disorder
Authors: Muralidharan Anjana , Kotwicki Raymond J. , Cowperthwait Colleen , Craighead W. Edward 
Published: December 2014

ObjectivesExpressed emotion (EE), or the presence of criticism/hostility/emotional overinvolvement in a family relationship, predicts poorer outcomes in bipolar disorder; however, the mechanism of this is unclear. The present study investigated whether, in a sample of young adults (aged 18–40 years) with bipolar disorder, parental criticism was associated with Behavioral Approach System (BAS) dysregulation, including emotional reactivity to negative feedback and cognitive schemas of self‐criticism/perfectionism.MethodTwenty‐two young adults with bipolar I disorder and 22 matched control participants completed an interview, questionnaires, and a computer‐based task with false negative feedback; emotional reactivity to this feedback was assessed.ResultsCompared to control participants, clinical participants exhibited higher levels (p = 0.001) of self‐criticism, and a trend towards a greater decrease in positive affect after negative feedback (p = 0.053), even when controlling for mood symptoms. Among clinical participants, perceived criticism from paternal caregivers was associated with self‐criticism and perfectionism, and low perceived paternal care was associated with decrease in positive affect.ConclusionStrain in parental relationships may be associated with BAS dysregulation for individuals with bipolar disorder.
Methanol feeding strategy design enhances recombinant human growth hormone production by Pichia pastoris
Authors: Güneş Hande , Boy Erdem , Ata Özge , Zerze Gül H , Çalık Pınar , Özdamar Tunçer H 
Published: December 2014

ABSTRACTBACKGROUNDThe effects of designed methanol and co‐substrate feeding strategies on fed‐batch recombinant human growth hormone (rhGH) production by Pichia pastoris hGH‐Mut+ were investigated.RESULTSThe highest cell concentration was obtained as 157 g L−1 with the exponential feeding strategy where methanol was fed at a pre‐calculated feeding rate based on pre‐determined µ0 = 0.03 h−1, and mannitol concentration was kept constant at 50 g L−1 for t=0–6 h. The highest rhGH concentration was obtained as 1.3 g L−1 at t=54 h with the methanol‐stat feeding strategy, where no co‐substrate was used and the methanol concentration was kept at 5 g L−1 in the medium during the production phase. Thereafter, in another methanol‐stat feeding strategy with pulse‐fed sorbitol, the highest rhGH concentration was obtained as 1.2 g L−1 at t=42 h.CONCLUSIONThe methanol‐stat fed‐batch method keeping methanol concentration constant at 5 g L−1 in the production medium increased rhGH production at least 2‐fold compared with that of the exponential feeding strategies. In the designed methanol‐stat feeding strategies, use of sorbitol as co‐substrate decreased methanol demand of the cells 2‐fold, increased the overall product yield on the substrate 1.6‐fold, shortened the cultivation time by 12 h and increased the productivity. Thus, methanol‐stat feeding with co‐substrate sorbitol was found to be a favorable fed‐batch strategy for rhGH production by Pichia pastoris under alcohol oxidase I promoter. © 2014 Society of Chemical Industry
The Effect of Landscape Conservation Measures in Changing Landscape Patterns: A Case Study in Mediterranean Mountains
Authors: Lasanta Teodoro , Nadal‐Romero Estela , Errea Paz , Arnáez José 
Published: December 2014

AbstractMediterranean mountain landscapes have high ecological and cultural values. However, since 1950, a large number of these landscapes have been subject to degradation as a consequence of land abandonment. Some regional administrations have enacted measures that favour the regeneration of pasturelands through scrubland clearing. The aim of this study was to evaluate the consequences of clearing and the regeneration of pasturelands on landscape structure and the recovery of extensive livestock in La Rioja. The results indicate that between 1986 and 2011 an area of 29,659 ha was cleared in the mountains of La Rioja, although 62·6% of this was cleared in the period 2000–2011. In 1956, the landscape was dominated by cultivated fields, but by 2001, much of the agricultural area had been abandoned and replaced by scrubland, natural woods and reforested areas. Furthermore, the landscape was more fragmented in 1956 than in 2001. The landscape structure varied following clearing, with a doubling in the number of patches and an increase in heterogeneity. The consequences of clearing have included an increase in the area of pastureland and the number of large animals. In addition, the number of farms has decreased, but their mean size has increased. Clearing is an appropriate way for spatial reorganization in marginal mountain areas. It does not require excessive investment but favours the reintegration of abandoned fields and an increase in pasturelands. The results of this study contribute to the debate about reclaiming mountain landscapes affected by human activities and subject to intense degradation processes. Copyright © 2015 John Wiley & Sons, Ltd.
Amine‐Functionalized Porous Polymer Network for Highly Selective Absorption of CO2 Over N2
Authors: Lee Doyun , Zhang Chengyi , Gao Haifeng 
Published: December 2014

Porous polymeric sorbents showing selective CO2 absorption over N2 are prepared by conventional radical copolymerization of divinylbenzene and 4‐vinylbenzyl chloride under solvothermal conditions, followed by surface modification of the pores with polyamines. The amine‐functionalized porous materials that interact with CO2 via chemisorption exhibit exceptionally high CO2/N2 select­ivity of up to 373 times, determined by ideal adsorbed solution theory (IAST).
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Numerical analysis of the geotechnical behaviour of energy piles
Authors: Di Donna AIice , Laloui Lyesse 
Published: December 2014

SummaryEnergy geostructures are rapidly gaining acceptance around the world; they represent a renewable and clean source of energy that can be used for the heating and cooling of buildings and for de‐icing of infrastructures. This technology couples the structural role of geostructures with the energy supply, using the principle of shallow geothermal energy. The geothermal energy exploitation represents an additional thermal loading, seasonally cyclic, which is imposed on the soil and the structure itself. Because the primary role of the piles is the stability of the superstructure, this aspect needs to be ensured even in the presence of the additional thermal load. The goal of this paper is to numerically investigate the behaviour of energy pile foundations during heating–cooling cycles. For this purpose, the finite element method is used to simulate both a single and a group of energy piles. The piles are subjected to a constant mechanical load and a seasonally cyclic thermal load over several years, imposed in terms of injected–extracted thermal power. The soil and the pile–soil interface behaviours are reproduced using a thermoelastic‐thermoplastic constitutive model. The thermal‐induced stresses inside the piles and the additional displacements of the foundations are discussed. The group model is used to investigate the interactions between the piles during thermo‐mechanical loading. The presented results are specific to the studied cases but lead to the conclusion that both the thermal‐induced displacements and stresses, despite being acceptable under normal working conditions, deserve to be taken into account in the geotechnical design of energy piles. Copyright © 2014 John Wiley & Sons, Ltd.
Tire footprint analysis depending on the elastokinematics of a multi‐link suspension system using multi‐body dynamics simulation
Authors: Kohl Sergej , Sextro Walter , Zuber Armin 
Published: December 2014

AbstractAn automotive suspension system represents one of the most complex and important systems in a passenger vehicle, which has to ensure a robust and optimized contact between the wheels and the road at any time. For improving a suspension system it is important to take an investigative look at the interaction between suspension, tire and road dynamics. Thus a part of a study into aspects of suspension modeling on multi‐body simulations of rear multi‐link suspension system dynamics with focus on the tire footprint area is presented in this work. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Time Optimal Path Planning for Industrial Robots: A Dynamic Programming Approach Considering Torque Derivative and Jerk Constraints
Authors: Oberherber Matthias , Gattringer Hubert , Springer Klemens 
Published: December 2014

AbstractThis paper presents a dynamic programming approach for calculating time optimal trajectories for industrial robots, subject to various physical constraints. In addition to path velocity, motor torque, joint velocity and acceleration constraints, the present contribution also shows how to deal with torque derivative and joint jerk limitations. First a Cartesian path for the endeffector is defined by splines using Bernstein polynomials as basis functions and is parameterized via a scalar path parameter. In order to compute the belonging quantities in configuration space, inverse kinematics is solved numerically. Using this and in combination with the dynamical model, joint torques as well as their derivatives can be constrained. For that purpose the equations of motion are calculated with the help of the Projection Equation. As a consequence of the used optimization problem formulation, the dynamical model as well as the restrictions have to be transformed to path parameter space. Due to the additional consideration of jerk and torque derivative constraints, the phase plane is expanded to a phase space. The parameterized restrictions lead to feasible regions in this space, in which the optimal solution is sought. Result of the optimization is the time behavior of the path parameter and subsequently the feed forward torques for the optimal motion on the spatial path defined by previously mentioned splines. Simulation results as well as experimental results for a three axes industrial robot are presented. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Energy‐optimized bipedal running of a simple humanoid robot
Authors: Römer Ulrich , Fidlin Alexander 
Published: December 2014

AbstractA method to optimize energy efficiency for bipedal running robots is presented. A running model of a simple bipedal robot consisting of five rigid bodies connected by actuated revolute joints is introduced. The actuators' torques are generated by a trajectory tracking controller to produce periodic running gaits. The controller's reference trajectories are parameterized by Bézier polynomials. A numerical optimization is used to employ reference trajectories with optimal energy efficiency for average velocities in the range of 1.5 to 5.5 m/s. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Computational modeling of cardiac tissue with strongly coupled electromechanics and orthotropic viscoelastic effects
Authors: Cansiz Baris , Dal Hüsnü , Kaliske Michael 
Published: December 2014

AbstractModeling of complex mechanisms leading to the functioning of the heart has been an active field of research since decades. Difficulties associated with in vivo experiments motivate the utilization of computational models in order to gain a better appreciation of heart electromechanics. Although rate dependent behaviour of the orthotropic passive heart tissue has been comprehensively studied in the literature [1], effects of this phenomenon on fully coupled cardiac electromechanics are unrevealed yet. Therefore, this contribution is concerned with the investigation of viscous effects on the electromechanical response of the myocardium. To this end, we adopt the fully implicit finite element framework which strongly couples the mechanical and electrophysiological problem of the myocardium in a mono‐ and bi‐domain setting [2,3], respectively. Viscous effects, however, are consistently embedded into this framework by making use of the orthotropic viscoelastic material model for the passive myocardium, which considers different relaxation mechanisms for the different orientation directions [5]. The performance of the proposed model is assessed by comparing finite element simulations of spiral waves in heart tissue for elastic and viscoelastic formulations. We further investigate the influence of viscosity on the defibrillation phenomenon by means of the finite element formulation of bidomain electrophysiology. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On dynamic finite element analysis of viscoplastic thin‐walled structures with non‐local damage: A phase‐field approach
Authors: Nguyen A.D. , Trinh B.T. , Stoffel M. , Markert B. 
Published: December 2014

Abstract[EN] In this work, a nonlocal damage model is proposed for dynamic analysis of viscoplastic shell structures using the phase‐field approach. A phase‐field variable on the mid surface is introduced to characterize the nonlocal damage as well as the transition between undamaged and damaged phase. The total free energy in [1] is modified as a sum of Helmholtz free‐energy and Ginzburg‐Landau one. The latter is defined as a function of the phase‐field variable and its corresponding gradient. This enhancement gives rise to an introduction of gradient parameters in terms of a substructure‐related intrinsic length‐scale. The evolution of the phase‐field based damage variable can be found from the minimum principle of the dissipation potential [3]. The performance of the proposed model is demonstrated through numerical results of a plate with a circular hole. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Phase field modeling of complex crack patterns in multi‐physics problems
Authors: Schänzel Lisa‐Marie , Ulmer Heike , Miehe Christian 
Published: December 2014

AbstractRecently developed continuum phase field models for brittle fracture show excellent modeling capability in situations with complex crack topologies including branching in the small and large strain applications. This work presents a generalization towards fully coupled multi‐physics problems at large strains. A modular concept is outlined for the linking of the diffusive crack modeling with complex multi field material response, where the focus is put on the model problem of finite thermo‐elasticity. This concerns a generalization of crack driving forces from the energetic definitions towards stress‐based criteria, the constitutive modeling of degradation of non‐mechanical fluxes on generated crack faces. Particular assumptions are made on the generation of convective heat exchanges approximating surface load integrals of the sharp crack approach by distinct volume integrals. The coupling effect is also shown in generation of cracks due to thermally induced stress states. We finally demonstrate the performance of the phase field formulation of fracture at large strains by means of representative numerical examples. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical aspects of failure modeling of amorphous thermoplastics
Authors: Schneider Konrad , Seelig Thomas 
Published: December 2014

AbstractThe present work investigates a reliable method of integrating the evolution equations of constitutive models for amorphous thermoplastics that typically utilize a power‐law or exponential‐type flow rule. When it comes to sudden changes in the external stress (e.g. element deletion technique in explicit finite element analysis) these functional dependencies need a special treatment to assure a numerically stable integration of the evolution equations. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Finite Element Simulation of Frost Wedging in Ice Shelves
Authors: Plate Carolin , Müller Ralf , Humbert Angelika , Gross Dietmar 
Published: December 2014

AbstractBreak‐up events in ice shelves have been studied extensively during the last years. One popular assumption links disintegration events to surface melting of the ice shelf in conjunction with growing melt‐water ponds, leading to hydro‐fracture. As this explanation only holds during warm seasons [1], the possibility of frost wedging as forcing mechanism for autumn and winter break‐up events is considered. Frost wedging can only occur if a closed ice lid seals the water inside the crack. Hence, the present study of frost wedging in a single crack uses ice lid thicknesses to evaluate the additional pressure on the crack faces. The investigation of the resulting stress intensity factor as a measure of crack criticality follows consequently. The results show that freezing water inside a crack can result in unstable crack growth of an initially stable water filled crack. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Phase Field Approximation of Dynamic Brittle Fracture
Authors: Schlüter Alexander , Kuhn Charlotte , Müller Ralf 
Published: December 2014

AbstractThe numerical assessment of fracture has gained importance in fields like the safety analysis of technical structures or the hydraulic fracturing process. The modelling technique discussed in this work is the phase field method which introduces an additional scalar field. The smooth phase field distinguishes broken from undamaged material and thus describes cracks in a continuum. The model consists of two coupled partial differential equations ‐ the equation of motion including the constitutive behaviour of the material and a phase field evolution equation. The crack growth follows implicitly from the solution of this system of PDEs. The numerical solution with finite elements can be accelerated with an algorithm that performs computationally extensive tasks on a graphic processing unit (GPU). A numerical example illustrates the capability of the model to reproduce realistic features of dynamic brittle fracture. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hypersingularities in three‐dimensional crack configurations in composite laminates
Authors: Hell Sascha , Becker Wilfried 
Published: December 2014

AbstractThree‐dimensional crack configurations in composite laminates are studied by means of the Scaled Boundary Finite Element Method (SBFEM) particularly regarding stress singularities and their associated deformation modes. The SBFEM is an efficient semi‐analytical method that permits solving linear elastic mechanical problems. Only the boundary needs to be discretized while the problem is considered analytically in the direction of the dimensionless radial coordinate pointing from the scaling center to the boundary . An important advantage is that it requires no additional effort for the characterization of existing stress singularities. The situation of two meeting inter‐fiber cracks is investigated in detail, considering different materials and fiber / crack orientations. It is shown that in three‐dimensional crack configurations in composite laminates so‐called hypersingularities can occur, i.e. stress singularities which are even stronger than the classical crack singularity. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Experimental and Numerical Investigations of Al/Mg Compounds
Authors: Kirbach Carola , Stockmann Martin , Ihlemann Jörn 
Published: December 2014

AbstractAl/Mg compounds produced by hydrostatic extrusion exhibit unique characteristics regarding high strength and low weight, which are required by safety part applications in lightweight constructions. Between the two materials an interface in form of a brittle intermetallic phase consisting of Al2Mg3 and Al12Mg17 arises during the production process. However, a certain plastic deformability of the semi‐finished product is essential for further forming processes. Even under multi‐axle load during a radial upsetting process, the interface maintains a full material joint although a fragmentation and a new secondary interface between the fragments can be observed. Due to the evaluations of light microscopy images and Eulerian Hencky strain values at the interface, which are obtained with the help of the Digital Image Correlation, a relation between the strain and the boundary layer's appearance seems reasonable. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Reduction of non‐linear drill string models using proper orthogonal decomposition
Authors: Kueck Armin , Recke Bastian , Ostermeyer Georg‐Peter 
Published: December 2014

AbstractOil service companies use highly complex drill string models to optimize drilling assemblies and to perform post‐drilling analysis. These drill string models are usually non‐linear, FEM based and able to describe arbitrary curved well bore geometries. One of the most critical parts is the description of the contact at the well bore wall. Due to the model's complexity, simulations in time domain are extremely expensive and can take days to weeks. Less results in the same time reduce the quality of optimization and parameter studies. Thus, one goal of research is to accelerate time domain simulations while maintaining an appropriate level of accuracy. One way to reduce simulation time is to lower the order of the system. There are a lot of common well‐developed order‐reduction‐techniques for linear‐systems, e.g., modal reduction. However, these methods cannot handle unilateral‐constraints as used for the wall contact description. Hence, a reduction technique for non‐linear systems is needed. A promising reduction method of this kind is the proper orthogonal decomposition (POD, also called Karhunen‐Loève Transformation). This technique determines the principal structure of motions based on time signal measurements. The system is then reduced by transforming it to a lower dimensional space build on these main structures. In this paper the POD will be applied to a basic drill string model. It is a 2D‐FEM beam‐element drill string system with linear penalty‐springs. Parameter studies of the contact stiffness and the degree of reduction will show the performance and possible gain of this reduction method. Finally advantages and inconveniences of this method for drill string dynamics will be discussed. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Static and dynamic behavior of a selected cable‐stayed footbridge with respect to change of the cable tension
Authors: Pakos Wojciech , Wójcicki Zbigniew 
Published: December 2014

AbstractThe paper presents the theoretical analysis of the possibilities of using the authors' own method of actively reducing resonant vibration in cable‐stayed footbridges. The method of actively reducing vibration was earlier tested on a laboratory model of a steel footbridge, [1]. The method relies on changing the static tension in chosen cables. The term “active” refers to the fact that the tension changes would only be introduced when resonant vibration of the structure occurred. A change in the cable tensions should cause a change of the natural frequencies for which resonant vibration amplification appeared earlier. Eigenproblem sensitivity analysis, formulated for the structure according to the second order theory, is the basis for choosing the cables in which the tension should change. Apart from analyzing the effectiveness of the active method for reducing resonant vibration, the influence of cable tension change on other values was also studied. These values included the changes in vibration amplitudes, as well as changes of cross‐section forces, tensions, and static bend of the structure elements that are most sensitive to tension change. It was also established whether the tension changes in chosen cables, which were large enough to cause a practically significant reduction of resonant vibration, cause exceeding the levels of Serviceability Limit State (SLS) and Ultimate Limit State (ULS) for the structure as a whole or for some of its elements. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)