bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Gaussian Process-Based Crack Pattern Modeling Approach for Battery Anode Materials Design
Authors: Zheng Zhuoyuan , Chen Bo , Xu Yanwen , Fritz Nathan , Gurumukhi Yashraj , Cook John , Ates Mehmet N. , Miljkovic Nenad , Braun Paul V. , Wang Pingfeng 
Published: April 2020

Abstract
Silicon-based anodes are one of the promising candidates for the next generation high-power/energy density lithium ion batteries (LIBs). However, a major drawback limiting the practical application of the Si anode is that Si experiences a significant volume change during lithiation/delithiation, which induces high stresses causing degradation and pulverization of the anode. This study focuses on crack initiation within a Si anode during the delithiation process. A multi-physics-based finite element (FE) model is built to simulate the electrochemical process and crack generation during delithiation. On top of that, a Gaussian process (GP)-based surrogate model is developed to assist the exploration of the crack patterns within the anode design space. It is found that the thickness of the Si coating layer, TSi, the yield strength of the Si material, σFc, the cohesive strength between Si and the substrate, σFs, and the curvature of the substrate, ρ, have large impacts on the cracking behavior of Si. This coupled FE simulation-GP surrogate model framework is also applicable to other types of LIB electrodes and provides fundamental insights as building blocks to investigate more complex internal geometries.
Energy Harvesting Performance of Vertically Staggered Rectangle-Through-Holes Cantilever in Piezoelectric Vibration Energy Harvester
Authors: Gao Shan , Ao Hongrui , Jiang Hongyuan 
Published: April 2020

Abstract
Piezoelectric vibration energy harvesting technology has attracted significant attention for its applications in integrated circuits, microelectronic devices, and wireless sensors due to high power density, easy integration, simple configuration, and other outstanding features. Among piezoelectric vibration energy harvesting structures, the cantilevered beam is one of the simplest and most commonly used structures. In this work, a vertically staggered rectangle-through-holes (VS-RTH) cantilevered model is proposed, which focuses on the multi-directional vibration collection. To verify the output performance of the device, this paper employs basic materials and fabrication methods with mathematical modeling. The simulations are conducted through finite element methods to discuss the properties of VS-RTH energy harvester on resonant frequency and output characteristics. Besides, an energy storage circuit is adopted as a collection system. It can achieve a maximum voltage of 4.5 V which is responded to the harmonic vibrating input of 1 N force and 1 m/s2 in a single vibrating direction. Moreover, the power density is 2.596 W/cm3 with a 100 kΩ resistor. It is almost four times better than the output of unidirectional cantilever beam with similar resonant frequency and volume. According to the more functionality in the applications, VS-RTH energy harvester can be used in general vibration acquisition of machines and vehicles. Except for electricity storage, the harvester can potentially employ as a sensor to monitor the diversified physical signals for smooth operation and emergence reports. Looking forward, the VS-RTH harvester renders an effective approach toward decomposing the vibration directions in the environment for further complicating vibration applications.
Structural Changes of TiO2 as a Result of Irradiation by E-Beam and X-Rays
Authors: Paunović Perica , Grozdanov Anita , Makreski Petre , Gentile Gennaro 
Published: April 2020

AbstractThe subject of this research was to monitor and evaluate the effect of X-rays and e-beam irradiation on the structure of nanoscaled TiO2 and its properties. The samples of nanoscaled TiO2 were synthesized using the sol–gel method and subsequently exposed to thermal treatment to obtain the anatase crystalline structure. X-ray powder diffraction (XRPD) and Raman spectroscopy revealed the following changes in the structure as a result of the e-beam and X-ray irradiation: a decrease in the size of the crystallite of TiO2, an increase of the distance between the crystalline planes and the lattice parameters as well as the achievement of a certain degree of amorphization. As a consequence of the structural changes, thermal stability decreased. Also, a shift of the light absorption toward the visible end of the spectrum was detected and the energy of the band gap was reduced, indicating a better photocatalytic activity, i.e., the photocatalytic action can be shifted to the region of the visible light.
Parametric Study and Uncertainty Quantification of the Nonlinear Modal Properties of Frictional Dampers
Authors: Sun Yekai , Yuan Jie , Pesaresi Luca , Denimal Enora , Salles Loïc 
Published: April 2020

Abstract
A numerical methodology is described to study the influence of the contact location and contact condition of friction damper in aircraft engines. A simplified beam model is used to represent the blade for the preliminary design stage. The frictional damper is numerically analyzed based on two parameters, contact angle and vertical position of the platform. The nonlinear modal analysis is used to investigate the nonlinear dynamic behavior and damping performances of the system. The harmonic balanced method with the continuation technique is used to compute the nonlinear modes for a large range of energy levels. By using such a modeling strategy, the modal damping ratio, resonant amplitude, and resonant frequency are directly and efficiently computed for a range of design parameters. Monte Carlo simulations together with Latin hypercube sampling is then used to assess the robustness of the frictional damper, whose contact parameters involve much uncertainties due to manufacturing tolerance and also wear effects. The influences of those two parameters are obtained, and the best performances of the frictional damper can be achieved when the contact angle is around 25 deg–30 deg. The vertical position of the platform is highly mode dependent, and other design considerations need to be accounted. The results have proved that the uncertainties that involved contact surfaces do not have significant effects on the performance of frictional damper.
The Effect of Surface Finish on the Proper Functioning of Underplatform Dampers
Authors: Gastaldi Chiara , Berruti Teresa M. , Gola Muzio M. 
Published: April 2020

Abstract
Underplatform dampers are used to limit the resonant vibration of turbine blades. In recent years, various strategies have been implemented to maximize their damping capability. Curved-flat dampers are preferred to ensure a predictable bilateral contact, while a pre-optimization procedure was developed to exclude all those cross-sectional shapes that will bring the damper to roll and thus limit the amount of dissipated energy. The pre-optimization bases its predictions on the assumption that the effective width of the flat contact interface corresponds to the nominal one. It is shown here that this hypothesis cannot be relied upon: the energy dissipated by two nominally identical dampers, machined according to the usual industrial standards, may differ by a factor up to three due to the morphology of the flat-to-flat contact interface. Five dampers have been tested on two dedicated test rigs, available in the AERMEC laboratory, specially designed to reveal the details of the damper behavior during operation. Their contact interfaces are scanned by means of a profilometer. In each case, the mechanics, the kinematics, and the effectiveness of the dampers in terms of cycle shape and dissipated energy are correlated to the morphology of the specific contact surface. To complete the picture, a state-of-the-art numerical simulation tool is used to show how this tribo-mechanic phenomenon, in turn, influences the damper effect on the dynamic response of the turbine.
Implementation and Comparison of Contact Models Within PIRAT for Nuclear Reactivity Control Systems
Authors: Bonney Matthew S. , Zabiégo Maxime 
Published: April 2020

AbstractThe reactivity control system is a vital safety system for a nuclear reactor. One of the most challenging aspects in the design of these systems is the operation during critical situations, in particular during earthquakes to safely shut-down the reactor. To study these situations, the toolbox python Implementation for Reliability Assessment Tools (PIRAT) is used to model two types of excitation: single frequency and realistic. The main focus of this work is the comparison of the implementation of the contact models used to describe the interaction between the subsystems. For the dynamic tool in PIRAT (dynamic Euler–Bernoulli for seismic event (DEBSE)), this is done with a two-stage linear spring or Lankarani and Nikravesh-based models. For the sine excitation, the results show four distinct response types with the maximum displacement varying between the models. Low-frequency excitation showed little variance while higher frequency excitation showed large variations. The realistic excitation, however, did not show these variations and showed nearly identical results for the contact models tested. This gives confidence in the simulations since the user selected contact model did not greatly affect the simulation results for a realistic excitation.
Detachment Waves and Self-Oscillation in a Belt-Drive System Incorporating Tensile Cords
Authors: Wu Yingdan , Varenberg Michael , Leamy Michael J. 
Published: April 2020

Abstract
Recent experimental studies have shown that tension transition via detachment waves (rather than via sliding, as commonly accepted) occurs at the belt–pulley interface for systems using simple homogeneous or textured flat belts operating under slow speeds. This raises the question of whether or not such detachment waves are universal—e.g., will they persist in systems incorporating belts with composite cross sections, such as those used in commercial applications? Herein, we experimentally explore the behavior of a belt-drive system incorporating a composite belt with tensile cords, with and without a patterned contact surface, and document the persistence of detachment waves. This then leads to a re-evaluation of the Firbank model of belt shear. We also explore the effect of tensile cords on (i) the amplitude and frequency of the observed detachment waves, (ii) the ensuing oscillations of the pulley, (iii) the evolution of belt shear strain, and (iv) the frictional losses of the system. We find that the detachment frequency increases and the pulley rotates steadier with inclusion of tensile cords. The corded belt undergoes shear deformation starting from the entry point due to a speed differential between the pulley envelope and the tension members, which is consistent with the classical Firbank shear model. However, the Firbank model cannot predict the rapid relaxation of the shear traction via detachment waves at the exit region. Additionally, accounting for shear and detachment events, we find that frictional losses in the belt-drive system decrease with inclusion of tensile cords.
Modeling, Analysis, and Control of SLIP Running on Dynamic Platforms
Authors: Iqbal Amir , Mao Zhu , Gu Yan 
Published: April 2020

AbstractThe complex dynamic behaviors of legged locomotion on stationary terrain have been extensively analyzed using a simplified dynamic model called the spring-loaded inverted pendulum (SLIP) model. However, legged locomotion on dynamic platforms has not been thoroughly investigated even by using a simplified dynamic model such as SLIP. In this paper, we present the modeling, analysis, and control of a SLIP model running on dynamic platforms. Three types of dynamic platforms are considered: (a) a sinusoidally excited rigid-body platform; (b) a spring-supported rigid-body platform; and (c) an Euler–Bernoulli beam. These platforms capture some important domains of real-world locomotion terrain (e.g., harmonically excited platforms, suspended floors, and bridges). The interaction force model and the equations of motion of the SLIP-platform systems are derived. Numerical simulations of SLIP running on the three types of dynamic platforms reveal that the platform movement can destabilize the SLIP even when the initial conditions of the SLIP motion are within the domain of attraction of its motion on flat, stationary platforms. A simple control strategy that can sustain the forward motion of a SLIP on dynamic platforms is then synthesized. The effectiveness of the proposed control strategy in sustaining SLIP motion on dynamic platforms is validated through simulations.
A New Index of Static Actuation Force Sensitivity of Mechanisms Based on Unified Forward Jacobian Matrix
Authors: Wang Xu , Guo Weizhong , Han Youcheng 
Published: April 2020

Abstract
This paper proposes a novel performance index, which is called static actuation force sensitivity (SAFS), to investigate the response of the actuation forces when the amplitude of the suffered load of the end-effector has a change. Smaller SAFS can protect the actuations, and the load is mainly suffered by the structural constraints. This work starts with the construction of the unified forward Jacobian matrix of both serial and parallel mechanisms by screw theory. Then, with the forward Jacobian matrix, the inverse static equation is established. SAFS is thus introduced by the “partial differential” operation on the inverse static equation. SAFS is only related to the position of the whole mechanism and the direction of the suffered load, but not related to the detailed value of the amplitude of the load and the detailed value of the actuation forces; thus, SAFS can reveal the essence of static force capacities of the mechanisms. The example mechanism (namely, the 3revolute-prismatic-spherical (RPS) parallel mechanism) is used to illustrate the distribution of SAFS both over the workspace and at a certain pose. The analysis method of SAFS and the proposed index are expected to be applied to the pose optimization in the motion planning of the mechanisms to protect the actuations.
A Hybrid Contact Implementation Framework for Finite Element Analysis and Topology Optimization of Machine Tools
Authors: Yuksel Esra , Erturk Ahmet Semih , Budak Erhan 
Published: April 2020

AbstractMachine tool contacts must be represented accurately for reliable prediction of machine behavior. In structural optimization problems, contact constraints are represented as an additional minimization problem based on computational contact mechanics theory. An accurate contact constraint representation is challenging for structural optimization problems: (i) “No penetration” rule dictated by Hertz-Signorini-Moreau (HSM) conditions at contacts is satisfied by varying the contact stiffness during a finite element (FE) solution without control of a user which causes increased contact stiffness “erroneously” to avoid penetration of contacting node pairs in an FE solution; and (ii) the reliability of solutions varies according to the chosen computational contact method. This paper is devoted to the topology optimization of machine tools with contact constraints. A hybrid approach is followed that combines the computational contact problem framework and an obtained stable contact stiffness function (analytically or experimentally). According to the proposed method, the existing optimization problem in FE literature is restated in a reliable form for machine tool applications. To avoid the existing computational challenges and reliability problems, contact forces are directly mapped onto an FE model used in the restated topology optimization problem with the help of proposed method. In this study, the existing and the proposed methods for contact are investigated by means of the solid isotropic material with penalization model (SIMP) algorithm for topology optimization. The effectiveness of the proposed method is demonstrated by comparing the experimental measurements on a prototype machine tool manufactured according to the optimization solutions of the proposed method and those of a conventional machine tool.
Impact of the PDFs on the Z and W lineshapes at LHC
Authors: Bertacchi Valerio , Bianchini Lorenzo , Manca Elisabetta , Rolandi Gigi , Chowdhury Suvankar Roy 
Published: April 2020

AbstractThe parton distribution functions (PDFs) of the proton play a role in determining the lineshape of Z and W bosons produced at the LHC. In particular, the mode of the gauge boson virtuality is shifted with respect to the pole due to the dependence of the partonic luminosity on the boson virtuality. The knowledge of this shift contributes to the systematic uncertainty for a direct measurement of the boson mass. A detailed study of the shift and of its systematic uncertainty due to the limited knowledge of the PDFs is obtained using a tree-level model of Z and W boson production in proton-proton collisions at $$\sqrt{s}=13~\hbox {TeV}$$s=13TeV. A Monte Carlo simulation is further used to validate the tree-level model and study the dependence of the shift on the transverse momentum of the gauge bosons. The tree-level calculation is found to provide a good description of the shift. The systematic uncertainty on the lineshape due to the PDFs is estimated to be below one MeV in the phase-space relevant for a future high-precision mass measurement of the gauge boson masses at the LHC.
Korean Nonprofit/Non-Government Sector Research: A Literature Review and Analysis
Authors: Kim Sung-Ju , Jung Jin-Kyung 
Published: April 2020

Abstract
Discourses on the nonprofit sector and civil society have elevated awareness of the significant growth of the sector’s roles and responsibilities since the early 1990s in South Korea (hereafter simply Korea). The nonprofit sector has played significant roles in promoting economic progress and democracy in Korea. Based on extensive empirical research and government statistics, this article presents the nature of the Korean nonprofit sector from various angles, including terminology, history, legal frames, size and dimensions, financial resources, changes in philanthropy and volunteer cultures, and social economic perspectives. In addition, the authors discuss contemporary issues for the nonprofit sector based on changes in the social environment.
In discussing the magnitude of the Korean nonprofit sector, this article makes three arguments. First, we confirm that the Korean nonprofit sector has rapidly grown in multidimensional aspects as the legal systems for the nonprofits have developed in Korea since World War II. The growth has been accelerated by strong government supports and initiatives. Second, we argue that lack of conceptual frameworks to identify the nonprofit sector and lack of a centralized administration system have hindered fully catching up on the nature of the nonprofit sector in Korea. Multiple legal frameworks and excessively complicated governing systems for the nonprofit sector have inhibited understanding the size and dimensions of the Korean nonprofit sector. This article further diagnoses the financial structures and the contemporary issues for the Korean nonprofit sector, discussing key suggestions for developing it.
Salvage Reconstructive Surgery During Nivolumab Therapy for a Patient With Hypopharyngeal Cancer
Authors: Tsushima Nayuta , Shinozaki Takeshi , Fujisawa Takao , Tomioka Toshifumi , Okano Wataru , Ikeda Masakazu , Tahara Makoto , Higashino Takuya , Hayashi Ryuichi 
Published: April 2020

Objectives: Nivolumab, a fully IgG4-programmed death-1 inhibitor antibody, led to improved overall survival compared with single-agent therapy in patients with platinum-refractory recurrent head and neck cancers. In general, nivolumab is used in inoperable patients. To the best of our knowledge, there have been no reports of salvage surgery during nivolumab therapy for patients with head and neck cancer. We report the case of a woman treated with salvage reconstructive surgery during nivolumab therapy. Method: Case report and literature review. Results: The patient underwent nivolumab therapy for recurrent primary and neck disease after induction chemotherapy, followed by concurrent chemoradiation therapy. The neck disease shrunk, whereas the primary disease temporarily shrunk but later progressed again. Recurrent primary disease led to a narrowing of her airway, and she required airway management. We performed total pharyngolaryngectomy with free jejunal reconstruction, and her quality of life improved. The surgery was performed without complications and the postoperative course was uneventful. She was discharged postoperative day 18 with oral intake function and a safer airway. Conclusion: As far as we know, this is the first report of salvage surgery during nivolumab therapy for patients with head and neck cancer. The salvage reconstructive surgery in this case proceeded uneventfully.
Early Myeloablative Allogeneic Stem Cell Transplantation during High-Dose Cytarabin Induced Cytopenia in Patients with Refractory or Relapsed Myeloid Leukemias.
Authors: Graef Thorsten T. , Neumann Frank F. , Fenk Roland R. , Kondakci Mustafa M. , Ruf Lailani L. , Steidl Ulrich U. , Haas Rainer R. , Kobbe Guido G. 
Published: April 2020

Abstract
Allogeneic stem cell transplantation is the most effective therapy for myeloid leukemias. Still, especially patients with refractory disease, unfavourable cytogenetics or blast transformation of a myeloproliferative disorder (mpd) have a poor prognosis as a result of a high rate of treatment related mortality and relapse with conventional conditioning regimens. Recently, Kolb et al. have introduced a sequential protocol utilizing early TBI-based non-myeloablative transplantation following conventional induction therapy in high-risk patients.
In this study, in dependence to Kolb, we have treated 21 patients (median age 51 years, range 17–63, 4 female, 17 male) with advanced leukemias according to an intensified sequential high-dose protocol. Diagnoses were AML (primary refractory 2, relapsed 5), MDS (refractory 7, untreated 1) and blast transformation of a MPD (refractory 6, untreated 0). The median blast count at induction was 22% (range 1–90) and 9 patients (43 %) had unfavourable cytogenetics. Induction therapy consisted of fludarabine, high-dose cytarabine with or without idarubicine, amsacrine or topotecan. ATG, high-dose melphalan with or without high-dose thiotepa was used for conditioning while patients were still cytopenic from the preceeding induction therapy. Following transplantation of a median of 6.1x10E6 CD34+ cells/kg (range 0.85–12.0) from related (6) or unrelated (15) donors, the median time to a wbc&gt;1000/μl and plt&gt;20000/μl was 15 days (range 10–24) and 17 days (range 8–30), respectively. No toxic death was observed during the first 30 days and 95% of patients achieved CR by day 28, 100% by day 50. Twelve patients (57%) developed aGvHD (12I-II°, 0III-IV°) and 7 patients (33%) at risk have developed chronic GvHD (5 limited, 2 extensive) so far. After a median time of 181 days (range 3 – 596 days) fifteen patients (72%) are alive and all are in complete remission. Six patients died, one of infection (5%), two of a combination of a chronic GvHD and infections (9%), two of disease progression (9%) and one patient from a second malignancy (SCLC).
We conclude that early sequential transplantation during induction therapy induced cytopenia using high-dose melphalan and thiotepa based conditioning is feasible and highly effective in patients with advanced myeloid leukemias and poor prognosis. Although these early results are promising, a longer follow up and comparison with standard regimens are required.