bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical Study of Long Separation Bubble on Slotted Thick Airfoil
Authors: Ramzi Mdouki 
Published: December 2018

AbstractThis work is aimed to examine the potential of two types of slots to control the long laminar separation bubble LoSB developed on the suction side of the thick symmetric NACA0021 airfoil. Two dimensional simulations are carried out under steady state and incompressible regime with the correlation‐based intermittency turbulent model in order to predict the boundary layer transition aspect. Two slots are included separately in the airfoil and are proposed as a passive tool to manipulate the LoSB under the effect of pressure gradient between both high and low pressurized zones. The results without control are confronted with experimental data and give a good validation. Concerning the controlled configurations, the transversal slot fails to manipulate the LoSB, while the longitudinal slot reveals its positive potential to control the LoSB and therefore enhancing the lift coefficient of the airfoil and the length of the SB, however, the drag coefficient was increased.
A finite‐element framework for the modelling and simulation of phase transforming magnetic solids using energy relaxation concepts
Authors: Bartel Thorsten , Kiefer Bjoern , Buckmann Karsten , Menzel Andreas 
Published: December 2018

AbstractIn this contribution we present a variational framework suitable for the finite element implementation of energy relaxation‐based dissipative magnetostriction and magnetic shape memory alloy models. Inspired by the non‐local nature of the magnetostatic energy stored in the self‐field associated with magnetised solids, three global fields are considered: the displacement field, the scalar magnetic potential, and additional state variable fields that parameterise the microstructure. This global variational three‐field problem is enhanced by the consideration of Karush‐Kuhn‐Tucker parameters—stemming from restrictions w.r.t. the microstructural variable evolution—at each node of the finite element mesh. This approach allows the simulation of magnetomechanically fully‐coupled, microstructure evolution‐driven responses in arbitrarily shaped domains.
Computational study of the interaction between degradation of biodegradable magnesium implants and bone remodelling
Authors: Ma Songyun , Markert Bernd 
Published: December 2018

AbstractBiodegradable magnesium implants are increasingly applied to promising orthopaedic fixation devices due to obvious advantages over conventional permanent implants. However, potential risks of environment assisted corrosion failures during their service in human body have not been systematically studied [1], which leads to a limitation of the extensive applications of the magnesium implants. In addition, the influence of the degradation process of magnesium implants on the bone remodelling after surgery is also a critical factor. Therefore, a modelling approach is required to understand their interactions with the physiological environment and improve the design of biodegradable magnesium implants with respect to the healing efficiency of fractured bones. In the present work, three‐dimensional computer simulations are conducted for a fractured femur fixed by the bone plate and screws to investigate the service behaviour of magnesium implants and their interaction with the bone healing process. A mechano‐regulatory model based on the biphasic stimuli is used to simulate tissue differentiation and bone remodelling of the fractured femur. A corrosion damage model is used to describe the complex degradation process of mechanical integrity of magnesium implants under physiological loadings. The simulation results are consistent with the experimental observation. The present modelling approach provides an efficient tool in the design and the performance evaluation of biodegradable magnesium implants.
Simulation of PCM‐saturated porous solid matrix for thermal energy storage using the phase‐field method
Authors: Sweidan Abdel Hassan , Heider Yousef , Markert Bernd 
Published: December 2018

AbstractLatent heat storage systems using phase change materials (PCMs) are considered an attractive technique for storing the available thermal energy due to their high energy storage capacity, compactness and ability to store heat at an almost constant temperature. However, the PCMs suffer from their low thermal conductivity that affects the heat transfer rates and leads to slow charging and discharging processes. Therefore, many approaches have been adopted for improving the low thermal conductivity of PCMs. In the underlying research work, a latent heat storage medium using a PCM‐saturated highly conductive porous metal foam is being studied. High porosity cellular metal foams are proved to be promising materials for enhancing the heat transfer performance of the PCMs due to their high surface area to volume ratio, ultra light weight and relatively high thermal conductivity. A macroscopic description of the PCM‐saturated porous material with intrinsically coupled and incompressible solid and fluid constituents is presented, based on the Theory of Porous Media (TPM). The heat transfer process between the metal foam and the PCM is described using the local thermal non‐equilibrium model, where the phase‐field method (PFM) is employed to account for the phase change process. The PFM relies on specification of the free energy density function and employs a phase‐field variable that defines the state of the material (solid or liquid). Finally, numerical examples using the finite element method are presented to show the ability of the phase‐field‐porous media approach in simulating the phase change problems on the macro scale.
Flatness‐based control of a rigid body carried by multiple heavy ropes
Authors: Irscheid Abdurrahman , Gerbet Daniel , Rudolph Joachim 
Published: December 2018

AbstractFlatness‐based trajectory planning for the distributed‐parameter system consisting of a rigid body carried by multiple heavy ropes is discussed. The suspension points (controlled ends) of the ropes are assumed to be freely movable. The other ends of the ropes are parametrized by a flat output of the nonlinear boundary system at the load that describes the motion of the rigid body. This parametrization is then used to express the solution of the linearized partial differential equations for the heavy ropes under small angle approximations around a vertical equilibrium configuration by the means of operational calculus. It is shown that the system trajectories of the ropes depend on distributed delays and advances of the flat output trajectory at the load‐side boundary system. Evaluating the derived parametrization of the heavy ropes at the controllable ends yields the desired open‐loop controller by using a planned trajectory for the flat output. This control can be used to realize a desired transition of the load position and orientation in finite time. The introduced method is illustrated for the example of a linear infinite‐dimensional model of two heavy ropes carrying a rigid rod.
A Filter‐Based Motion Cueing Algorithm for a Redundant Driving Simulator
Authors: Ellensohn Felix , Breyer Manuel , Schwienbacher Markus , Venrooij Joost , Rixen Daniel 
Published: December 2018

AbstractA Motion Cueing Algorithm (MCA) determines the simulator's input subject to the driving dynamics demands. Main limitations form the technical restrictions of the simulator's actuators on position, velocity and acceleration level. This paper shows a filter‐based MCA for a redundant motion system exhibiting nine degrees of freedom (DoF). The redundant DoF are distributed by a frequency divider. A parameter optimization scheme is shown to estimate the unknown parameters of the MCA subject to the tilt restrictions and the exploitation of the actuators.
Numerical investigations of diffusion coefficients in the context of multi‐component gas transport within the Theory of Porous Media
Authors: Thom Andrea , Ricken Tim , Koßler Marvin , Gehrke Tobias , Denecke Martin , Widmann Renatus , Schulte Marcel , Schmidt Thorsten C. 
Published: December 2018

AbstractIn order to simulate methane oxidation within landfill covers in changing environmental conditions, a computational approach via the extended Theory of Porous Media (eTPM) was created. Its purpose is to gain an overall view on the ongoing processes such as concentration progression of methane, oxygen, carbon dioxide and nitrogen. For that, advective and diffusive transport mechanisms as well as energy production from the exothermic oxidation reaction are considered. Regarding the diffusive gas transport different approaches to model the diffusion coefficient are made use of.
Damage evolution in fiber reinforced polymer‐metal joints – modeling and simulation
Authors: Hirsch Franz , Kästner Markus 
Published: December 2018

AbstractIn this contribution, the interface behavior of an aluminum component connected to an FRP is considered on the microscale. Different local features, e.g. the surface roughness, fibers near the interface and local failure of the polymer material and their effects on the overall interface characteristics are investigated. Computational homogenization schemes enable the derivation of effective traction‐separation laws for representative interface elements. The polymer material can exhibit large deformations up to failure, which is modeled with a gradient‐enhanced finite strain elastic‐plastic damage model.
A nonlinear FE‐HMM formulation along with a novel algorithmic structure for finite deformation elasticity
Authors: Eidel Bernhard , Fischer Andreas , Gote Ajinkya 
Published: December 2018

AbstractThis contribution presents a nonlinear formulation of the Finite Element Heterogeneous Multiscale Method (FE‐HMM) for the homogenization of microheterogeneous solids. Moreover, a novel algorithmic structure is proposed for FE‐HMM, FE2 and alike, which enables for hyperelastic constitutive laws a considerable speed‐up compared to the existing standard.
A coupled thermo‐poro‐mechanical model of the breast applied to breast cancer detection
Authors: Niedermeyer Angela , Ma Songyun , Markert Bernd 
Published: December 2018

AbstractRecently, diagnostic methods based on infrared thermographic imaging of the skin have shown promising results regarding skin cancer detection. The application to breast cancer has not yet led to satisfying results. The challenge lies in determining the location and intensity of the embedded cancerous heat source from measured infrared radiation of the breast surface. For this purpose, a coupled poro‐thermo‐mechanical constitutive model of the breast is proposed here, which describes the energy transport in this soft tissue. In this work, numerical simulations of a breast model containing a tumor are conducted to study the correlation between skin temperature and tumour characteristics. The results demonstrate that the proposed modelling approach can be employed to determine optimal measurement conditions such as surrounding temperature and to evaluate the potentialities of transient measurements.
Towards the generation of dry patient‐specific human aortic valve models from medical imaging data
Authors: Morales Ortuno Sergio , Röehrle Oliver 
Published: December 2018

AbstractConsidering the geometry of the human aortic valve as one of the key factors influencing directly on its function, deformation and performance, we focus on the generation of 3‐D Finite Element Models (FEMs) of these valves under healthy and diseased conditions from patient‐specific geometries extracted from medical imaging data.
Partitioned simulation of the fluid‐structure interaction of flexible marine propellers in unsteady flow conditions
Authors: Lampe Tobias , Radtke Lars , Abdel‐Maksoud Moustafa , Düster Alexander 
Published: December 2018

AbstractRegarding new propeller materials and designs, vibrations and large deformations are becoming increasingly relevant. Therefore, simulation methods need to be developed which take into account the interaction of fluid and structure while retaining a computational effort suitable for the design stage. In the approach presented here, the fluid mechanical subproblem is solved by means of the software panMARE, which is based on the potential theory. The structural‐mechanical subproblem is engaged using different structural solvers as well as modelling approaches. Information exchange between the subproblems is managed by the software comana.
Interactive Web Apps for Visualizations in Mathematics and Engineering
Authors: Taddei Francesca , Rüth Benjamin , Karpfinger Christian , Müller Gerhard 
Published: December 2018

AbstractDepicting numbers in a graphical way has always been crucial to understand and explain the physical phenomena behind. Interactive graphical applications bring the understanding to a higher level, where the users get actively engaged. Moreover, interactive visualization of data, equations etc.… help to motivate students and strengthen the sharing of knowledge. At the Technical University of Munich, the Chair of Structural Mechanics and the Research Group Algebra developed interactive applications in the fields of mechanics and higher mathematics. Students can access the applications online at any time, without installation or special requirements, and, thus, can actively explore the content with a very low entry barrier. For example, they can experiment with a spring‐mass‐damper system and let it enter the resonance by changing the frequency of the excitation; or they can search for local maxima and minima of a function with side conditions with the Lagrange multipliers in an interactive and graphical way. The interactive process enhances the understanding, even if the user does not interact with a strategy but just uses his intuition. These applications can be also used to explain complex concepts to the general public. The source code is publicly available on
https://github.com/ChairOfStructuralMechanicsTUM/Mechanics_Apps
.
Lower gamma globulin level before conditioning is a risk factor for cytomegalovirus antigenemia after pediatric allogeneic stem cell transplantation
Authors: Kobayashi Ryoji , Hori Daiki , Matsushima Satoru , Sano Hirozumi , Suzuki Daisuke , Kobayashi Kunihiko 
Published: December 2018

AbstractBackgroundDespite the development of early detection methods and new antiviral drugs, cytomegalovirus (CMV) infection remains a persistent and sometimes severe complication of stem cell transplantation (SCT). CMV antigenemia has become widely used for early detection of CMV infection after SCT.ProcedureWe retrospectively analyzed risk factors for CMV antigenemia in pediatric patients following allogeneic SCT. We analyzed 74 pediatric patients who received allogeneic SCT at Sapporo Hokuyu Hospital between April 2007 and March 2018 and were alive over three months after SCT.ResultsOf the 74 patients, 22 (29.7%) were CMV antigenemia positive. On univariate analyses, many patients with CMV antigenemia tested positive for CMV antibody before SCT (P < 0.001), and had lower gamma globulin levels before conditioning (P = 0.014). Multivariate analysis additionally confirmed that pre‐SCT CMV antibody positivity (P < 0.001) and preconditioning gamma globulin levels under 655 mg/dL (P = 0.004) were independent risk factors for post‐SCT CMV antigenemia.ConclusionsThese results indicate the importance of assessing gamma globulin levels in pediatric patients prior to SCT.
Adolescent and young adult cancer care: Financial hardship and continued uncertainty
Authors: Parsons Susan K. , Kumar Anita J. 
Published: December 2018

AbstractSince 2005, there has been a steady increase in the number of new cancer diagnoses among adolescents and young adults (AYA) in the United States (US), likely due to improved awareness and detection within this age group, as well as the possible contribution of insurance expansion under the Patient Protection and Affordable Care Act. AYAs with cancer remain highly vulnerable financially, a situation that will only worsen with proposed rollbacks in access to and affordability of healthcare. In this review, we will discuss existing aspects of financial hardship and highlight areas of uncertainty, based on the current US political climate.
Influence of overloading on the reliability and critical components of networked critical infrastructures
Authors: Zhu Huaxing , Zhang Chi , Ouyang Min 
Published: December 2018

AbstractThe economic development and social well‐being of modern societies are highly dependent on networked critical infrastructures to satisfy the necessary demand. In the case that the prescribed demand cannot be satisfied with each component of a network normally loaded, certain components need to be overloaded. To study the influence of overloading on the network reliability, this research proposes a new flow‐redistribution rule based on minimal cuts to determine the components to overload when necessary and the way to redistribute the network flow. The proposed rule can help to keep the prescribed demand for a network satisfied, while trying to minimize the adverse influence of overloading on the network reliability. Based on the proposed rule, we then propose a bi‐objective optimization model to identify a network's critical components that, among all the possible combinations of components with the same amount, influence the network reliability the most when incapacitated, while considering the possibility of overloading and its influence on the reliability.
Do Resources Matter? Effects of an In‐Class Library Project on Student Independent Reading Habits in Primary Schools in Rural China
Authors: Yi Hongmei , Mo Di , Wang Huan , Gao Qiufeng , Shi Yaojiang , Wu Paiou , Abbey Cody , Rozelle Scott 
Published: December 2018

AbstractIt is commonly believed that reading challenges should be addressed early to reduce the likelihood that developmental delays will impact students over the long term. However, students in developing countries often have limited access to reading resources. In this study, the authors used a randomized controlled trial of 11,083 fourth‐ and fifth‐grade students in 120 primary schools in rural China to examine the causal effect of an in‐class library program on student reading outcomes and academic achievement in schools with poor reading resources over an eight‐month period. An in‐class library was installed in each of the selected classes in the 40 treatment schools. The authors found that the program significantly improved student affinity toward reading and student reading habits, and in these regards, it narrowed the gap between male and female students, between low‐ and high‐performing students, and between left‐behind children and children living with parents. However, the authors found no overall effect of the program on reading and academic achievement and a negative effect on student confidence in reading. There was also no effect on student, teacher, and primary caregiver perceptions toward the effect of independent reading on academic achievement, nor any effect on whether teachers and primary caregivers provided reading instructions to students. The authors propose three possible explanations for these findings: a lack of reading instruction from teachers and caregivers, a lack of reading materials specifically tailored to local needs and interests, and the relatively short duration of the intervention.
A Hybrid Kinetic Analysis of the Biosolids Pyrolysis using Thermogravimetric Analyser
Authors: Patel Savankumar R. , Kundu Sazal K. , Halder Pobitra K. , Setiawan Adi , Paz‐Ferreiro Jorge , Surapaneni Aravind , Shah Kalpit V. 
Published: December 2018

AbstractIn this study, multi‐heating rate and multi‐temperature pyrolysis experiments of mechanically and biologically treated Australian biosolids is conducted in a Thermogravimetric Analyser (TGA). A hybrid approach is applied for the estimation of kinetic parameters of biosolids pyrolysis where model‐free methods such as Kissinger–Akahira–Sunose (KAS) and Ozawa–Flynn–Wall (OFW) are used to derive activation energy while model‐fitting method such as Coats‐Redfern is used to derive pre‐exponential factor. The results obtained from this study are compared with other biosolids, lignocellulosic biomass, microalgae and coal. The activation energy and pre‐exponential factor obtained in the current work are 99.75 kJ/mol and 1.7×109 min−1 respectively. The coefficients of determination (R2) obtained in the determination of activation energies ranged between 0.93 and 0.99.
Ambient Degradation‐Induced Spin Paramagnetism in Phosphorene
Authors: Chen Jie , Zhou Qionghua , Pan Hongzhe , Zhang Weili , Zhao Yunlei , Deng Yu , Du Youwei , Wang Jinlan , Tang Nujiang 
Published: December 2018

AbstractThe sizeable direct bandgap, high mobility, and long spin lifetimes at room temperature offer black phosphorus (BP) potential applications in spin‐based semiconductor devices. Toward these applications, a critical step is creating a magnetic response in BP, which is arousing much interest. It is reported here that ambient degradation of BP, which is immediate and inevitable and greatly changes the semiconducting properties, creates magnetic moments, and any degree of degradation leads to notable paramagnetism. Its Landau factor g measured is ≈1.995, revealing that the magnetization mainly results from spin rather than orbital moments. Such magnetism most likely results from the unsaturated phosphorus in the vacancies which are stabilized by O adatoms. It can be tuned by changing any one of the ambient factors of ambient temperature, humidity, and light intensity, and can be stabilized by exposing BP in argon. The findings highlight the importance of evaluating the effect of ambient degradation‐induced magnetism on BP's spin‐based devices. The work seems an essential milestone toward the forthcoming research upsurge on BP's magnetism.
E2R‐F2N: Energy‐efficient retailing using a femtolet‐based fog network
Authors: Mukherjee Anwesha , De Debashis , Buyya Rajkumar 
Published: December 2018

SummaryEnergy‐efficient smart retail system design is a challenging research area. In this paper, we propose an automated retail system using a femtolet‐based fog network. A femtolet is an indoor base station providing computation and storage. Femtolets in our system work as indoor base stations and maintain databases of the products located in their respective coverage areas. The femtolets switch to active or idle mode according to the user's presence in its coverage. A smart trolley is proposed for our retailing system, which guides the user to the particular product type selected by the user. The user, after entering the shopping mall, carries the smart trolley. The customer selects and purchases products using this trolley. On the basis of product purchasing, the respective databases maintained inside the femtolets are updated. An Android application for the proposed retailing is developed. We compare the power consumption and delay of the proposed retail system with the existing retail system. Simulation analyses illustrate that the proposed approach reduces power by approximately 89% and 94%, respectively, in comparison to the local cloud server–based and remote cloud server–based retail systems. Thus, we refer to the proposed system as a green retail system. The performance of the proposed system through experimental analysis is also evaluated.