bluuebunny/crossref_metadata_2025_split huggingface dataset:
The structure of magnetic turbulence in the heliosheath region observed by Voyager 2 at 106 AU
Authors: Fraternale Federico , Pogorelov Nikolai V , Richagrdson John D. , Tordella Daniela 
Published: June 2019

Abstract
It is currently believed that the turbulent fluctuations pervade the outermost heliosphere. Turbulence, magnetic reconnection, and their link may be responsible for magnetic energy conversion in these regions. The governing mechanisms of such anisotropic and compressible magnetic turbulence in the inner heliosheath (IHS) and in the local interstellar medium (LISM) still lack a thorough description. The present literature mainly concerns large scales which are not representative of the inertial-cascade dynamics of turbulence. Moreover, lack of broadband spectral analysis makes the IHS dynamics critically understudied. Our recent study [1] shows that 48 s magnetic-field data from the Voyager mission are appropriate for a spectral analysis over a frequency range of six decades, from 5 × 10−8 Hz to 10−2 Hz. Here, focusing on the Voyager 2 observation interval from 2013.824 to 2016.0, we describe the structure of turbulence in a sector zone of the IHS. A spectral break around 7 × 10−7 Hz (magnetic structures with size ℓ ≈ 1.3 Astronomical Units) separates the energy-injection regime from the inertial-cascade regime of turbulence. A second scale is observed around 6 × 10−5 Hz (ℓ ≈ 0.017 AU) and corresponds to a peak of compressibility and intermittency of fluctuations.
A Dynamical Model of the Heliosphere with the Adaptive Mesh Refinement
Authors: Matsumoto Tomoaki , Shiota Daikou , Kataoka Ryuho , Miyahara Hiroko , Miyake Shoko 
Published: June 2019

Abstract
A three-dimensional time-dependent heliospheric model is developed with the adaptive mesh refinement (AMR) technique. The AMR code, SFUMATO, is adopted, which has been originally developed for star-formation problems. The solar wind model is based on the space weather forecast system, SUSANOO, and it is imposed on the inner boundary at r = 25 R
⊙. The solar wind model is derived from magnetogram synoptic maps, which are observed daily. Using the potential field source surface models, the WS formula, and a few empirical laws, the MHD parameters at the inner boundary are reproduced. The heliospheric model here extends up to 14 au, and the AMR grid resolves the heliospheric current sheets and co-rotating interaction regions with refined resolutions. The AMR grid brings considerable improvement in the fine features in the outer region of r ≳ 2 au compared to the concentric nested grid, of which resolution has the relationship Δx ∝ r, similar to spherical coordinates. The refinement criteria are based mainly on the distance from the Sun, the anti-parallel toroidal magnetic fields, and the density of the solar wind.
Particle-in-Cell Simulations of Plasma Dynamics in Cometary Environment
Authors: Sishtla Chaitanya Prasad , Olshevsky Vyacheslav , Chien Steven W. D. , Markidis Stefano , Laure Erwin 
Published: June 2019

AbstractWe perform and analyze global Particle-in-Cell (PIC) simulations of the interaction between solar wind and an outgassing comet with the goal of studying the plasma kinetic dynamics of a cometary environment. To achieve this, we design and implement a new numerical method in the iPIC3D code to model outgassing from the comet: new plasma particles are ejected from the comet “surface” at each computational cycle. Our simulations show that a bow shock is formed as a result of the interaction between solar wind and outgassed particles. The analysis of distribution functions for the PIC simulations shows that at the bow shock part of the incoming solar wind, ions are reflected while electrons are heated. This work attempts to reveal kinetic effects in the atmosphere of an outgassing comet using a fully kinetic Particle-in-Cell model.
GPU Acceleration of an Established Solar MHD Code using OpenACC
Authors: Caplan R. M. , Linker J. A. , Mikić Z. , Downs C. , Török T. , Titov V. S. 
Published: June 2019

Abstract
GPU accelerators have had a notable impact on high-performance computing across many disciplines. They provide high performance with low cost/power, and therefore have become a primary compute resource on many of the largest supercomputers. Here, we implement multi-GPU acceleration into our Solar MHD code (MAS) using OpenACC in a fully portable, single-source manner. Our preliminary implementation is focused on MAS running in a reduced physics “zero-beta” mode. While valuable on its own, our main goal is to pave the way for a full physics, thermodynamic MHD implementation. We describe the OpenACC implementation methodology and challenges. “Time-to-solution” performance results of a production-level flux rope eruption simulation on multi-CPU and multi-GPU systems are shown. We find that the GPU-accelerated MAS code has the ability to run “zero-beta” simulations on a single multi-GPU server at speeds previously requiring multiple CPU server-nodes of a supercomputer.
thornado-transport: IMEX schemes for two-moment neutrino transport respecting Fermi-Dirac statistics
Authors: Chu Ran , Endeve Eirik , Hauck Cory D. , Mezzacappa Anthony , Messer Bronson 
Published: June 2019

Abstract
We develop implicit-explicit (IMEX) schemes for neutrino transport in a background material in the context of a two-moment model that evolves the angular moments of a neutrino phase-space distribution function. Considering the upper and lower bounds that are introduced by Pauli’s exclusion principle on the moments, an algebraic moment closure based on Fermi-Dirac statistics and a convex-invariant time integrator both are demanded. A finite-volume/first-order discontinuous Galerkin(DG) method is used to illustrate how an algebraic moment closure based on Fermi-Dirac statistics is needed to satisfy the bounds. Several algebraic closures are compared with these bounds in mind, and the Cernohorsky and Bludman closure, which satisfies the bounds, is chosen for our IMEX schemes. For the convex-invariant time integrator, two IMEX schemes named PD-ARS have been proposed. PD-ARS denotes a convex-invariant IMEX Runge-Kutta scheme that is high-order accurate in the streaming limit, and works well in the diffusion limit. Our two PD-ARS schemes use second-and third-order, explicit, strong-stability-preserving Runge-Kutta methods as their explicit part, respectively, and therefore are second-and third-order accurate in the streaming limit, respectively. The accuracy and convex-invariance of our PD-ARS schemes are demonstrated in the numerical tests with a third-order DG method for spatial discretization and a simple Lax-Friedrichs flux. The method has been implemented in our high-order neutrino-radiation hydrodynamics (thornado) toolkit. We show preliminary results employing tabulated neutrino opacities.
Video Processing Techniques for the Contactless Investigation of Large Oscillations
Authors: Civera M , Zanotti Fragonara L , Surace C 
Published: June 2019

Abstract
The experimental acquisition of large vibrations presents various technical difficulties. Especially in the case of geometric nonlinearities, dealing with very flexible, very light structures causes minimal variations in mass or stiffness to affect severely the dynamical response. Thus, sensors’ added masses change the behaviour of the structure with respect to the unloaded condition. Moreover, the most common tools regularly employed for acquisition in vibration analysis - that is to say, laser vibrometers and accelerometers - are often designed with small amplitudes in mind. Their recordings are known to lack accuracy when the investigated structure undergoes large or very large motions, due to geometrical reasons. Image-based measurement techniques offer a valid solution to this problem. Here, an ensemble of three video processing techniques are benchmarked against each other and tested as viable options for the non-contact dynamic characterisation of slender beam-like structures. The methods have been applied to the case study of an aluminium spar for a highly-flexible airwing prototype and compared to the measurements recorded by a laser velocimeter and several Raspberry PI Inertial Measurement Units (IMUs), which also proved to be minimally invasive.
Patient Specific Diagnostics for cardiovascular diseases based on diagnostic imaging: an application to the aneurism of the ascending aorta
Authors: Querzoli G. , Satta V. , Matta G. , Ferrari S. , Badas M. G. , Bitti G. 
Published: June 2019

Abstract
In the framework of a collaboration between clinicians and engineers (namely, the Department of Radiology of the Brotzu Hospital in Cagliari and the group of experimental hydraulics at DICAAR - University of Cagliari), methodologies for the application of the in vitro study of the cardiovascular fluid mechanics to the support of the physical interpretation of the diagnostic imaging data are being tested. To this aim, we set up a mock-loop able to reproduce the physiologic pulsatile flow and designed to host a replica of aortic root made of transparent silicon rubber. Then, we developed a procedure to obtain a transparent and compliant replica of a patient specific ascending aorta from diagnostic images. The patient specific aorta model can be inserted in the mock-loop to study the fluid dynamics by means of particle image velocimetry techniques. We compared the flow in three cases, corresponding to physiological conditions, mild and severe aortic root dilation, observing significant differences in the redirection of the transvalvular jet and vortex evolution in the aortic flow. The observed fluid dynamics differences may have relevant implications on the thromboembolism and vascular tissue damage potential.
A non-invasive stochastic-optical method (SOM) for estimating the volume fraction in granular flows: application on interrogation windows with different aspect ratios
Authors: Sarno Luca , Nicolina Papa Maria , Tai Yih-Chin , Carleo Luigi , Villani Paolo 
Published: June 2019

Abstract
Granular flows are involved in geophysical phenomena and industrial applications. The knowledge of the volume fraction is essential for better understanding their dynamics. Indeed, this quantity is highly coupled with the rheology of granular media. Here, we investigated the performance of the stochastic-optical method (SOM), proposed by [Sarno et al. Granular Matter (2016) 18: 80]. The method works thanks to highly-controlled illumination conditions, guaranteed by a flickering-free planar lamp, and uses a high-speed digital camera. Namely, the indirect estimation of the near-wall volume fraction c3D
is made possible by the estimation of a quantity, called two-dimensional volume fraction c2D
, which is measurable through an opportune binarization of gray-scale images. With the purpose of assessing the performance of the SOM method on rectangular interrogation windows with different aspect ratios, we present a novel experimental campaign on dispersions of matte-white plastic beads immersed in a dense fluid, where the angle of incidence of light was 25°. Moreover, we explored various settings of the binarization algorithm, incorporated in the SOM method. The accuracy of the method is found to be reasonably high with a root-mean-square error on c3D
lower than 0.03 for a wide range of settings and independently from the aspect ratio.
Hull wake measurement in steady drift using a boroscopic stereo-PIV system
Authors: Capone A , Alves Pereira F , Maiocchi A , Camussi R , Di Felice F 
Published: June 2019

Abstract
Particle Image Velocimetry measurements in towing tanks usually require ad-hoc solutions to address the need to protect electronic equipment from water. Pioneering works in this field rely upon fully underwater probe systems to address this issue, as in [1]. In this work we present an approach based on the use of endoscopic equipment (boroscopes) to carry out towing-tank Stereo PIV (SPIV) measurements of the hull wake of a ship model in steady drift. A boroscopic SPIV system provides increased flexibility thanks to the absence of water-proof camera casings. The only underwater components of the presented apparatus are the boroscope tubes and the light-sheet forming device, which are not critical in terms of water protection. The major drawbacks are the reduced light-collecting efficiency of the boroscope devices as well as the geometric deformations and aberrations due to the short focal length, which must be specifically addressed with adequate algorithms. The boroscope-based SPIV system presented in this work features three cameras for redundancy and to increase measurement accuracy. We present the results of towing-tank testing of the hull wake of a twin-screw model at Froude number Fr = 0.24 in straight-ahead and steady drift conditions.
Feasibility study of FBG-based sensors for prognostics in aerospace applications
Authors: Berri P C , Dalla Vedova M D L , Maggiore P , Scolpito T 
Published: June 2019

Abstract
In recent years, aerospace systems have undergone a huge technical-scientific impulse, evolving new high-performance intelligent solutions able to perform diagnostic and prognostic functions autonomously. In this scenario, an important role is certainly played by the new types of sensors combining high performance (in terms of sensibility, accuracy, and reliability) with a marked resilience to external disturbances (e.g. EM noise or electrostatic discharges) and other environmental factors. Fiber Bragg Gratings (FBGs)sensors, suitable for measuring various engineering parameters in both static and dynamic modes, meet all these requirements; in aerospace, they could replace several traditional sensors, not only in structural monitoring but also in a much wider range of system applications including the diagnostic and prognostic of mechatronic devices. In this paper, the authors propose the first results of their investigation about the use of optical sensors for Electromechanical (EMA) and Electrohydrostatic Actuators (EHA). FBGs allow determination of aerodynamic hinge loads and minimally invasive measurements of local temperatures: the firsts are needed for in-flight model-based prognostics, whereas the detection of local heating allows to early infer an incipient partial short circuit of EM motor, a progressive power electronics failure or abnormal friction dissipation e.g. at bearing level. In order to assess the capabilities of optical sensors, evaluating different installation techniques and defining suitable configurations for the aforementioned mechatronic systems, a dedicated test bench has been developed and used for calibrating FBGs, analyzing their behaviour in different conditions of strain and temperature and conceiving a proper thermo-mechanical compensation strategy.
Place Energy and Urban Scene Drama in Iraqi City Centers (Case study Rusafa district in Baghdad-Iraq)
Authors: Hamzah Malk Jamal , AbdulJalil Mustafa 
Published: June 2019

Abstract
The concept of place energy aroused as one of the historical concepts of active regeneration over time, several studies have tried to activate its part in dealing with the place, but all of them have addressed the place internally only and didn’t take into consideration the outer part of place. Because of the prominence of this concept in our urban life, this study has tried to activate the concept of place energy at the urban level to go beyond the cramped frame that was created for it. Where the place has outstanding importance in making human interaction within society, particularly its urban part. The study will analyze the energy of the place which is related to people’s collective events and the memory of city residents, and how to deal with it and adapt it to the formation of the urban structure which gets closer to the ideal, and the possibility of benefiting from it in dealing with the spatial and the social dimensions within the city, while giving planning decisions to help activating this energy towards the Urban scene drama with which the community interacts and produces a live drama, this research focuses on the concept of place energy that shows the relationship between humans and place. The collective memory of the people will be adopted to discover their mental map according to their relative priority to the urban event to determine the important landmarks of the city and thus the energy nodes in the city, then these nodes will be analyzed in space syntax to reach to the relationship between these nodes and the urban structure, to reach to a scenario that arranges the urban scene.
Sustainable engineering factors Affecting the generation of dwelling Solid Waste in some Residential neighborhoods in the Karkh district of Baghdad City in 2014
Authors: Alwan Kareem Hassan , Hamden Maarib Youssef 
Published: June 2019

Abstract
The world concern deeply in the creation of a healthy and happy environment for sustainable human living, to improve the human output in all activities of the life, so it is significantly concerned in finding the best procedure in the disposal of solid waste from the urban area. The recent improvements in economic, social and environment due to the national development and spatial analysis, led to increase in solid waste generated from different sources and to increase in the demands on this service, so it is necessary to study, and analysis quality and quantity of generated solid wastes effected on this problem. This study expresses the indicators in four selected neighborhoods of Baghdad residential areas in engineering and planning views by using quantitative approaches with the help of the different statistical methods. The researchers get off the effected of many variables; This discrepancy was due to a change in the behavior of the community and the diversity of the needs of its adult and child members as a result of the change in the general lifestyle. The problem of research is the environmental problems due to the accumulation of solid waste regarding health, environment aesthetic, and the lack of identification of indicators affecting them. Most urban areas suffered from increasing the volume of substantial waste dwelling from the residential area relative to the speed and convenience of dealing with techniques methods of modern planning ensure fair distribution of service based on updated planning indicators. Updating the spatial, temporal, engineering and economic indicators that have a limited impact on achieving the practical goal of this service and ensuring its continuity efficiently when dealing with the factors affecting the generation of household waste in residential areas. Identification and spatial analysis of factors affecting environmental pollution due to the generation of household waste using plastic bags in the study area by using quantitative and statistical methods. Several explanatory indicators can be used to estimate the number of plastic bags offered by dwelling units in the study area to decrease environmental pollution.
Improvement of the Traffic Management of Deactivated Al-Faris Al-Arabi Signalized Roundabout in Baghdad City
Authors: Al-Obaidi Mahmood K J 
Published: June 2019

Abstract
Baghdad city, the capital of Iraq has mainly suffered from influences of transportation highway modes especially at intersections. Traffic management system TMS leads to improve the level of service LOS of the intersections by reducing traffic congestion, delay and time wasted during travel. This research studied the improving of TMS for deactivated Al-Faris Al-Arabi signalized roundabout that considered the important area near city center. Traffic data collected manually by group of engineers during March and April, 2018. Highway Capacity Software HCS2010 used to assess and improve the TMS for current and future forecasted flow. Results showed that roundabout operating on LOS F with a high delay of time and saturation flow. Three solutions proposed to improve the traffic conditions considering of modifying the geometric features with changing and optimizing the timing plan of traffic signals. It showed a highly improving in LOS from F to B, improving saturation flow to less than one and reducing in delay time to about 43 times of that at existing conditions. In addition to analysis results, 18 years has been expected to carry the future forecasted data. Finally, architectural model has been achieved to display the pre and post improvement of the study area.
The impact of UAV flight planning parameters on topographic mapping quality control
Authors: Ali H H , Abed F M 
Published: June 2019

Abstract
There is a growing need for up-to-date data for rapid decision making in the modern digital age. Recently, the need for high-resolution topographic maps is highly demanding by most mapping clients. With the maturing automatic structure from mobile and multi-view stereoscopy software, small organizations and individuals now have the ability to make their own surveys based on mobile mapping devices. This study looks at how feasible using low-cost Unmanned Aerial Vehicle (UAV) as a mobile mapping device for photogrammetric topographical surveys. It is showing the impact of different UAV flight settings and parameters on the accuracy of mapping products. An automatic scenario for photogrammetric flight mission and its execution are proposed and described. The focus of this research is to generate 3D point clouds from digital imagery using low-cost UAV and showing the relationship between flight mission settings and the quality of the delivered 3D data. Automatic solution is presented and analysed, which automatically generate 3D point clouds from arbitrary image configurations. Results delivered within millimetres based on specific flight setting and optimal quality control considerations. Accuracy assessment and validation process was adopted based on statistical assessments according to ground truth 3D adjusted measurements to assure validity.
Dynamic modulus of elasticity of geopolymer lightweight aggregate concrete
Authors: Khalil Wasan I , Abbas Waleed A , Nasser Ibtesam F 
Published: June 2019

Abstract
The production processes of ordinary Portland cement (OPC), accompanying with bad environment influences such as, huge energy consumption, greenhouse gases emissions and natural resource exploitation; but fly ash-based geopolymer concrete is produced without (OPC), yet that has many sustainable environment benefits. In this study locally artificial lightweight aggregate was used to produce lightweight fly ash geopolymer concrete. The dynamic modulus of elasticity for geopolymer lightweight concrete produced by using locally artificial aggregate was investigated. Reference lightweight geopolymer concrete containing natural normal weight fine aggregate without fiber, lightweight geopolymer concrete reinforced with two volume fractions of steel fibers (0.25 and 0.5); in addition to four concrete mixtures containing artificial coarse lightweight aggregate and artificial lightweight fine aggregate with 25, 50, 75 and 100% volumetric replacement to natural normal weight fine aggregate (sand) were prepared. The dynamic modulus of elasticity was tested at 28day age for all specimens using resonance frequency method. The results demonstrate that the incorporation of artificial fine lightweight aggregate as a volumetric replacement to natural fine aggregate in concrete geopolymer lightweight concrete reduces the dynamic modulus of elasticity gradually with the increase of artificial lightweight aggregate content.