bluuebunny/crossref_metadata_2025 huggingface dataset:
Le couple aptus-praestantia dans l’ Éthique de Spinoza
Authors: Legeay Vincent
Published: September 2019

L’article entend montrer que la notion d’ aptus et la notion de praestantia , au scolie de la proposition 13 de la seconde partie de l’ Éthique , constituent un couple remarquable non anodin, parce qu’en partie repris à Hobbes. Après avoir analysé la teneur de cette reprise, depuis l’œuvre du philosophe anglais, dans le vocabulaire spinoziste, nous avançons que l’aptitude ne peut pas être comprise comme une valeur rapprochée de la puissance optimale, telle qu’elle a parfois été interprétée mais plutôt comme une position gnoséologique favorable vis-à-vis des causes extérieures contrariantes que sont les circonstances, et que l’on pourrait assimiler à une forme de complexité au sens contemporain.
Présentation
Authors: de Negroni Barbara
Published: September 2019

Le texte de Pierre Francastel que nous publions ici est une communication faite durant un colloque consacré à Nicolas Poussin, qui eut lieu à Paris du 19 au 21 septembre 1958. L’ensemble des communications a été publié, sous la direction d’André Chastel, aux Éditions du CNRS, Paris, 1960. Dans ce texte, Francastel propose une lecture de l'évolution de l'œuvre de Poussin et montre la profonde inventivité de sa peinture.
On the time decay in phase–lag thermoelasticity with two temperatures
Authors: Magaña Antonio , Miranville Alain , Quintanilla Ramón
Published: September 2019

The aim of this paper is to study the time decay of the solutions for two models of the one-dimensional phase-lag thermoelasticity with two temperatures. The first one is obtained when the heat flux vector and the inductive temperature are approximated by a second-order and first-order Taylor polynomial, respectively. In this case, the solutions decay in a slow way. The second model that we consider is obtained taking first-order Taylor approximations for the inductive thermal displacement, the inductive temperature and the heat flux. The decay is, therefore, of exponential type.
Visualization of buried anti‐tank landmines and soil pollution: analyses using ground penetrating radar method with attributes and petrographical methods
Authors: Kadioğlu Selma , Kadioğlu Yusuf Kagan
Published: September 2019

This paper presents an approximation to display buried anti‐tank landmines with ground‐penetrating radar method, including physical data attributes by measuring data in a special military field and determination of soil pollution using mineralogical and chemical features of the soil obtained by confocal Raman spectrometry and polarized energy dispersive X‐ray fluorescence, which are petro‐graphical methods, before and after bursting the mine. Two‐dimensional ground penetrating radar data were acquired on parallel profiles using 800‐MHz shielded antenna on unexploded anti‐tank landmines buried approximately 10 cm–15 cm in depth. After general processing in the time domain, we employed migration, a frequency‐wavenumber (F‐K) filter, and ground‐penetrating radar data attributes with an amplitude envelope, spectral whitening, and first‐time derivative to activate anti‐tank landmine visualization. Finally, we obtained three‐dimensional half bird ‘s eye view of the processed volume with each separate attribute. We also derived the transparent three dimensional volumes by assigning opacity to the amplitude‐colour range. The results showed that the depth slices including attributes and the transparent three‐dimensional depth‐volumes could clearly image the anti‐tank landmine. In addition, migration and F‐K filter during special processing were very important in removing data noise. Ground‐penetrating radar data atthbutes—particularly amplitude enveloping— could suppress small phase shifts in the neighbouhng traces of the landmine amplitude anomalies and helped to obtain more complete results showing location and depth in the three‐dimensional volume.

The results of the analyses of the major oxide elements and heavy metal elements, such as Fe2O3 Pb, Zn, As, Mn, Mo, Co, Ni, Sb, and Sn, in the test area revealed that there were almost no major differences before and after blasting the anti‐tank landmines. This indicates that one‐time bursting of the anti‐tank landmines in the field has not polluted the soil in this area.
Physical characterisation of soils recovered from the ANZAC battlefield
Authors: Orangi Amir , Narsilio Guillermo A.
Published: September 2019

As part of a unique tri‐nation study to commemorate the centenary of the iconic First World War ANZAC battlefield, this paper summarises the results of a laboratory experimental investigation of some geotechnical and geophysical characteristics of soil recovered from this field in Gallipoli, Turkey. The geophysical characterisation of these samples comprises the determination of the dielectric properties, namely real, imaginary and dielectric dispersion, over a frequency band between 200 MHz and 6 GHz. This characterisation is performed at the samples’ in situ state as well as in a controlled range of water content from oven‐dried to saturation. Specific frequencies pertaining to certain in situ geophysical applications and satellite surveys have been targeted as reference frequencies to study the dielectric data. Moreover, attenuation coefficients related to ground‐penetrating radar applications are also estimated at 200 MHz for a range of water contents. Microstructure and mineralogy were examined by environmental scanning electron microscopy and X‐ray diffraction techniques, respectively. Given the historical and archaeological significance of the ANZAC battlefield, these results can be used for future feasibility studies, planning, and result interpretation of geophysical investigations, including choosing the most appropriate time of the year and geophysical prospection tools, in this restricted‐access study area.
The 3D Autojuggie: automating acquisition of 3D near‐surface seismic reflection data
Authors: Miller Brian E. , Sloan Steven D. , Tsoflias Georgios P. , Steeples Don W.
Published: September 2019

New instrumentation, known as the 3D Autojuggie, has been developed that allows acquisition of three‐dimensional shallow seismic reflection data in a cost‐effective manner. The 3D Autojuggie is capable of simultaneously planting 220 geophones with 0.5‐m spacing in the inline and crossline directions in less than 1 minute. Likewise, all 220 geophones can be picked up in the same amount of time so that the receiver grid can be moved and redeployed on the order of a few minutes without disconnecting cables and seismographs. This significantly reduces the time required to roll geo‐phones and cables and the number of crew members needed for three‐dimensional high‐resolution seismic surveying. While efficiency of three‐dimensional surveying is demonstrated here, the use of the Autojuggie will be limited in rough terrain and in dry or rocky top soil.

This study presents two field tests of the 3D Autojuggie. The first one was conducted over soil using conventional geophones with spikes, and the second one was conducted over hard pavement using geophones mounted on base plates. Each dataset is compared to corresponding walkaway lines of conventional manually placed control geophones. Data acquired using the 3D Autojuggie are directly comparable and nearly indistinguishable to hand‐planted geophones. Field experiments resulted in a minimum of triple the acquisition efficiency increase compared with conventional geophone deployment methods. This work demonstrates that the 3D Autojuggie can facilitate the acquisition of high‐resolution three‐dimensional seismic data, making possible routine ultra‐shallow seismic imaging.
Using ground‐penetrating radar to explore the cemented soil horizon in an arid region in Iran
Authors: Abbaszadeh Afshar Farideh , Ayoubi Shamsollah , Castrignanò Annamaria , Quarto Ruggiero , Mahmoudzadeh Ardekani Mohammad Reza
Published: September 2019

Petrosalic horizon (cemented by soluble salts) is identified as a root‐restricting layer in the arid and semi‐arid regions. The knowledge of the variability of cemented layers within the soil profiles provides valuable information to decision‐makers for agricultural and/or engineering activities. This study was conducted to evaluate the potential of ground‐penetrating radar in detecting petrosalic horizon within the soil pedon in an arid area (Kerman Province, southeastern Iran). The measurements were performed using an impulse ground‐penetrating radar system with a centre frequency of 250 MHz along ten parallel transects of 100‐m length and 10‐m distance between two consecutive transects at two sites. The results of the soil stratigraphy indicated the presence of petrosalic horizons at 12‐ to 36‐cm depth. The ground‐penetrating radar images showed patterns corresponding to these soil horizons. The interpreted radargrams were quite consistent with the findings of the soil pedons. It is, therefore, suggested that ground‐penetrating radar could be employed to detect the boundaries between different soil horizons in the arid areas with various degrees of conductivity. This, in turn, helps differentiate soil‐mapping units and improve the reliability and accuracy of digital soil maps. The results confirmed that ground‐penetrating radar could be used as a rapid, efficient and non‐destructive tool providing highresolution and continuous visualisation of the soil horizons to detect the presence and depth of petro‐salic horizons. Such information could be crucial in making decisions in agricultural practices (e.g., creating gardens) and engineering activities (e.g., constructing roads and buildings).
Probe rotation effects on direction of arrival estimation in array‐type directional borehole radar
Authors: Ebihara Satoshi , Wada Kazushige , Karasawa Shinsuke , Kawata Kentaro
Published: September 2019

This paper discusses the relationship between feeding line delay compensation and direction of arrival estimation in an array‐type directional borehole radar. In this radar, since the space available for an array antenna is limited by the borehole diameter, direction of arrival estimation is based on small travel time differences among array elements, and an accurate compensation of feeding line delays is important. Computer simulation confirmed that the radar probe rotation in a borehole leads to errors in the direction of arrival estimation of greater than 15° if the delays associated with the feeding array antenna elements are not compensated to within 0.1 ns. This may be caused by a failure to measure the time delays of electrical circuits around the feeding points of the antenna elements. In this case, we suggest that the lengths of system components other than the coaxial cables should be kept to less than 3 cm. Based on these investigations, we developed an array‐type directional borehole radar for a geotechnical project to locate foundation piles. In a field experiment, we confirmed that direction of arrival estimation errors were below about 15°, although the radar probe rotated through more than 180° during the measurement, thanks to correct compensation of the cables. With the correct compensation, we demonstrated three‐dimensional location of a buried cylindrical conducting object, which was located at 2 m from the radar in wet soil. We were able to estimate the reflection point position with an accuracy of 34 cm, which is the averaged error of the three‐dimensional location, while allowing the radar probe to rotate.
A shear‐wave seismic system using full‐waveform inversion to look ahead of a tunnel‐boring machine
Authors: Bharadwaj Pawan , Drijkoningen Guy , Mulder Wim , Thorbecke Jan , Neducza Boriszlav , Jenneskens Rob
Published: September 2019

In the near surface with unconsolidated soils, shear‐wave properties can often be characterised better and with a higher resolution than compressional‐wave properties. To enable imaging ahead of a tunnel‐boring machine, we developed a seismic prediction system with a few shear‐wave vibrators and horizontal receivers. The boring process is interrupted at regular intervals to carry out active surveys. The vibrators are then pushed against the rock or soil in front of the cutting wheel of the machine. The design of the vibrators is based on linear synchronous motor technology that can generate very low frequencies, starting at 5 Hz. These vibrators generate a force in a direction perpendicular to the tunnel axis. Horizontal receivers measure the particle velocity, mainly due to the horizontally polarised shear waves. Because imaging with conventional migration methods suffers from artefacts, caused by the incomplete aperture and inaccuracies in the assumed velocity model, we use two‐dimensional horizontally polarised shear full‐waveform inversion to resolve the subsurface shear properties. The classic cycle‐skipping problem, which can make the application of full‐waveform inversion cumbersome, is avoided by the capacity of the vibrators to generate low frequencies. In this paper, we demonstrate the capabilities of the proposed seismic system through a number of synthetic and field experiments.
Forward and inverse modelling of electrical properties of some sandstone rocks using renormalisation group method
Authors: Gomaa Mohamed M. , Kassab Mohamed A.
Published: September 2019

Electrical properties of some sandstone rocks (conductivity and dielectric constant) were investigated as a function of frequency (100 Hz to 100 kHz). Such heterogeneous specimens contain semiconducting constituents (silt and clay) and insulating constituents (sand, air, and carbonates). A theoretical pseudo‐random renormalisation group method was used to predict the electrical properties of such random mixture. Four phases were used in the model to consider the detailed texture of the constituent materials. The measured electrical properties (conductivity and dielectric constant) versus frequency of these samples were analysed to predict the texture or connections of these four phases. From the analysis, these four phases were suggested to be (1) carbonates, (2) sand coated with clay and coated with air, (3) carbonates coated with clay and coated with air, and (4) pure sand. The forward problem predicts the electrical properties versus frequency using the pseudo‐random renormalisation group method for certain concentrations of the constituent materials distributed among the random four phases. The forward model is used to fit the measured response to obtain the expected concentrations of rock constituents in the proposed four phases using a parameter search method (inverse problem). The obtained accordance between the experimental and modelled characteristics in much of the frequency band used suggests that the pseudo‐random renormalisation group method with the supposed four phases reasonably represents the main mineralogical composition of the rock.
Direct monitoring of active geohazards: emerging geophysical tools for deep‐water assessments
Authors: Clare Michael A. , Vardy Mark E. , Cartigny Matthieu J.B. , Talling Peter J. , Himsworth Matthew D. , Dix Justin K. , Harris John M. , Whitehouse Richard J.S. , Belal Mohammad
Published: September 2019

Seafloor networks of cables, pipelines, and other infrastructure underpin our daily lives, providing communication links, information, and energy supplies. Despite their global importance, these networks are vulnerable to damage by a number of natural seafloor hazards, including landslides, turbidity currents, fluid flow, and scour. Conventional geophysical techniques, such as high‐resolution reflection seismic and side‐scan sonar, are commonly employed in geohazard assessments. These conventional tools provide essential information for route planning and design; however, such surveys provide only indirect evidence of past processes and do not observe or measure the geohazard itself. As such, many numerical‐based impact models lack field‐scale calibration, and much uncertainty exists about the triggers, nature, and frequency of deep‐water geohazards. Recent advances in technology now enable a step change in their understanding through direct monitoring. We outline some emerging monitoring tools and how they can quantify key parameters for deep‐water geohazard assessment. Repeat seafloor surveys in dynamic areas show that solely relying on evidence from past deposits can lead to an under‐representation of the geohazard events. Acoustic Doppler current profiling provides new insights into the structure of turbidity currents, whereas instrumented mobile sensors record the nature of movement at the base of those flows for the first time. Existing and bespoke cabled networks enable high bandwidth, low power, and distributed measurements of parameters such as strain across large areas of seafloor. These techniques provide valuable new measurements that will improve geohazard assessments and should be deployed in a complementary manner alongside conventional geophysical tools.
Measurement of geophysical parameters on clay samples at the solid–fluid transition
Authors: Carrière Simon R. , Bièvre Gregory , Jongmans Denis , Chambon Guillaume , Bellot Hervé , Lebourg Thomas
Published: September 2019

Fluidisation occurring in clay‐rich landslides poses serious threats to populations and infrastructures and has been the subject of numerous studies to apprehend its rheological origin. In parallel, noninvasive geophysical techniques for monitoring landslides have shown considerable developments as a means to obtain thein‐situgeotechnical parameters. This study investigates the influence of fluidisation on two geophysical parameters: the shear wave velocity,, and the electrical resistivity,. Both parameters are widely used in landslide monitoring as they are sensitive, respectively, to soil stiffness and water content, two key parameters for material fluidisation. Laboratory tests were carried out on soil samples collected in five flow‐like landslides occurring in very different geological conditions. A plate–plate rheometer was used to provoke fluidisation, andwas measured during oscillatory tests. The rheometer was redesigned for resistivity measurements, incorporating circular electrodes in polyvinyl chloride plates. Results show that (i) all soils exhibit a dramatic drop inat the fluidisation, and (ii) the resistivity does not significantly vary at the solid–fluid transition. These last results are analysed in terms of clay particles arrangement using the laws of Archie and Waxman–Smits, and the impact on geophysical monitoring of a landslide is discussed.
Electrical properties of two‐component mixtures and their application to high‐frequency IP exploration of permafrost
Authors: Zorin Nikita , Ageev Dmitriy
Published: September 2019

We investigate the problem of determination of the volumetric ratio between the two components of a heterogeneous mixture with unknown internal structure. If both resistivity and permittivity of one component are known to be much higher than those of the other within a sufficiently wide frequency range, the volumetric ratio may be roughly estimated from measured electromagnetic response of the mixture by making use of the variational approach. Otherwise, such estimation requires the exact knowledge of the inherent electrical properties of the mixed materials and application of some universal mixing model, such as the weighted power mean formula.

The high‐frequency induced polarization measurements are strongly influenced by the presence of ice inclusions in an investigated rock formation, which is commonly used for mapping of frozen ground within the permafrost regions. We show that for sedimentary rocks with low clay content, it is also possible to roughly estimate the ice concentration from broadband induced polarization data by using the two‐component, weighted power mean model, which is confirmed by a lab experiment on a frozen core sample with known ice content.
Spectral induced polarization for the characterisation of biochar in sand
Authors: Gao Zhan , Haegel Franz-Hubert , Huisman Johan A. , Esser Odilia , Zimmermann Egon , Vereecken Harry
Published: September 2019

The use of biochar as a soil amendment attracts increasing research interest. However, the lack of methods to detect and monitor biochar in situ limits the validation of the field‐scale application of biochar. Spectral induced polarization is a potential tool to characterise biochar in soil. The aim of this study is to investigate the sensitivity of spectral induced polarization to biochar in sand and to understand how the physicochemical properties of both the biochar and the surrounding matrix influence the spectral induced polarization response. To this end, spectral induced polarization measurements were conducted on four types of biochar with different mass fractions disseminated in saturated sand as a host media with changing electrical conductivity. In addition, it was investigated how the spectral induced polarization response depends on the particle size of biochar. The measured SIP data were interpreted by Debye decomposition to obtain values for the peak relaxation time, ; total chargeability, ; and normalised total chargeability, . Spectral induced polarization showed a clear and specifically differentiated response to the presence of all four types of biochars. was found to be proportional to the mass fraction of biochars, although relationships varied for each type of biochars. of biochars increased with increasing particle size. Increased electrolyte concentration enhanced for all biochars, although again, the specific response was different for each biochar. In addition, higher electrolyte concentrations decreased for biochars derived from wood through pyrolysis but did not affect of biochar derived from miscanthus through hydrothermal carbonisation. It was concluded that the spectral induced polarization response of pyrolytic biochars resembled that of conductors or semiconductors, whereas the spectral induced polarization response of hydrothermal carbonisation biochar more closely resembled that of clay. Overall, the findings in this study suggest that spectral induced polarization is a promising method for the detection and characterisation of biochar in soil.
Measurement of dielectric and magnetic properties of materials by means of a TDR probe: a preliminary theoretical investigation in the frequency domain
Authors: Persico Raffaele , Pieraccini Massimiliano
Published: September 2019

This paper is focused on the measurement of both dielectric and magnetic characteristics of a penetrable material at radio frequency through a time‐domain reflectometry probe. The goal is to prove that a time‐domain reflectometry probe can offer the possibility to discriminate the dielectric permittivity from the magnetic permeability of the material. This is due to the fact that the time‐domain reflectometry datum depends both on the propagation velocity of the electromagnetic waves in the probed medium and on the intrinsic impedance of the probe. However, the possibility to attain such a clear discrimination is bound by the condition that the reflection coefficient is measured (or calculated) along the probe at the air–soil interface in the frequency domain. Generally, time‐domain reflectometry probes measure the total (incident plus reflected) field in the time domain, and subsequently, the datum is needed to meet the condition that such claimed purpose is not just the Fourier transform of a datum collected by means of a common time‐domain reflectometry probe. Rather, either a devoted hardware should be implemented or a very accurate knowledge of the incident field should be guaranteed in order to separate the reflected wave from the incident one. In this preliminary work, our study has been restricted to a theoretical investigation in the frequency domain. In particular, our focus is set on the lossless case, and the attention is devoted to the issue of possible multiple solutions to demonstrate that this obstacle can be overcome by making the frequency step narrower or, alternatively, by narrowing the length step of the probe. Simulation results based on a bifilar transmission line model are shown.
Mapping geological structures in bedrock via large‐scale direct current resistivity and time‐domain induced polarization tomography
Authors: Rossi Matteo , Olsson Per‐Ivar , Johanson Sara , Fiandaca Gianluca , Preis Bergdahl Daniel , Dahlin Torleif
Published: September 2019

An investigation of geological conditions is always a key point for planning infrastructure constructions. Bedrock surface and rock quality must be estimated carefully in the designing process of infrastructures. A large direct‐current resistivity and time‐domain induced‐polarization survey has been performed in Dalby, Lund Municipality, southern Sweden, with the aim of mapping lithological variations in bedrock. The geology at the site is characterised by Precambrian granitic gneisses and amphibolites, which are intensely deformed, fractured, and partly weathered. In addition, there are northwest‐trending Permian dolerite dykes that are less deformed.

Four 2D direct‐current resistivity and time‐domain induced‐polarization profiles of about 1‐km length have been carefully pre‐processed to retrieve time‐domain induced polarization responses and inverted to obtain the direct‐current resistivity distribution of the subsoil and the phase of the complex conductivity using a constant‐phase angle model. The joint interpretation of electrical resistivity and induced‐polarization models leads to a better understanding of complex three‐dimensional subsoil geometries. The results have been validated by lithological descriptions from several drillings. In addition, direct‐current resistivity and time‐domain induced‐polarization logging has been carried out in two different boreholes, showing a good match with the results of the surface direct‐current resistivity and time‐domain induced‐polarization profiles.

The direct‐current resistivity and time‐domain induced‐polarization methodology proved to be a suitable technique for extensively mapping weathered zones with poor geotechnical characteristics and tectonic structures, which can lead to severe problems for infrastructure construction and/or constitute risk zones for aquifer contamination.
Terrestrial and marine electrical resistivity to identify groundwater pathways in coastal karst aquifers
Authors: O’Connell Yvonne , Daly Eve , Henry Tiernan , Brown Colin
Published: September 2019

Groundwater movement in karst aquifers is characterised by high‐velocity fissure and conduit flow paths, and in coastal karst aquifers, these act as pathways for saline intrusion and freshwater discharge to the sea. This paper examines groundwater movement in two neighbouring catchments in the west of Ireland that represent canonical coastal karst aquifers dominated by discharges in the intertidal zone and at offshore submarine springs. Terrestrial and surface‐towed marine electrical resistivity tomography, coupled with ancillary hydrogeological data, identifies the influence of faulting and conduits on groundwater egress/saltwater ingress. The on‐shore and off‐shore subsurface geometry of major fault zones is identified, and the tidal influence of seawater and ground‐water flow is demonstrated in these zones and karst springs. Imaging of these sub‐surface structures is a pre‐requisite for numerical modelling of current and future climate‐driven freshwater–seawater interactions in karst coastal aquifers.
La formation du supérieur : un levier de transformation des universités québécoises
Authors: Lison Christelle , Paquelin Didier
Published: September 2019

Depuis le Moyen Âge, les universités ont progressivement quitté leur fonction première centrée sur l’enseignement pour donner davantage de place à la recherche. Une culture et des pratiques professionnelles fortement ancrées dans une approche magistro-centrée semblent aujourd’hui moins en adéquation avec les attentes et les besoins des apprenants comme des acteurs du monde socio-économique actuel. La transformation des pratiques pédagogiques devient une impérative nécessité, qui suppose un accompagnement des enseignants visant le développement d’un nouveau corpus de gestes professionnels appuyé sur des capacités et des compétences parfois éloignées de leur cœur de métier. Pour y parvenir, plusieurs universités québécoises ont investi dans la formation des enseignants afin de créer une dynamique collective qui, partant des pratiques actuelles, vise un bien-être pédagogique fondé sur la réflexivité étayée par les résultats de la recherche en pédagogie de l’enseignement supérieur. Sans en faire une obligation, elles considèrent que proposer des espaces de développement professionnel pédagogique amène des retombées non seulement pour les individus qui s’y engagent mais aussi à l’échelle institutionnelle.
L’Université virtuelle du Sénégal, une réponse à la massification et aux inégalités d’accès à l’enseignement supérieur
Authors: Mbengue Abdourahmane , Meinertzhagen Lionel
Published: September 2019

Pour répondre aux défis de la massification et de l’inégalité d’accès dans l’enseignement supérieur d’Afrique subsaharienne, la formation à distance est reconnue comme une solution. Créée en 2013, l’Université virtuelle du Sénégal est rapidement devenue la première université publique entièrement numérique en Afrique francophone subsaharienne et la deuxième en termes d’effectifs au Sénégal. L’article présente les dispositifs de formation en ligne, tels que des plateformes à distance (Moodle), des classes virtuelles (Blackboard collaborate) et un réseau d’espaces numériques ouverts (ENO) disséminés dans différentes régions du pays. Il analyse ensuite les difficultés de démarrage et les conséquences sur la perception de l’opinion, les premières leçons tirées et les mesures de remédiations prises pour une montée en puissance de l’UVS. L’ambition est d’en faire un acteur africain incontournable de la pédagogie universitaire numérique.
Beryllium Effect on the Energy Band Gaps and the Electronic Charge Density of the Alloy (Be, Cd) Se
Authors: Saheb Hadjer , Bechiri Abderrachid
Published: September 2019

In the present study, we have computed the electronic band structure and electronic charge density of the alloy (Be, Cd)Se in the zinc-blende structure; using the local Empirical Pseudopotential Method (EPM), which takes into account the disorder effect into the Virtual Crystal Approximation (VCA) by introducing an effective potential disorder. The obtained results show a reasonable agreement with the available experimental data. Detailed plots of the valence charge distribution along the [111] direction and in the (110) plane are also presented and discussed.
Microstructural Aspects of the Zircaloy-4/SS-304L Interface Obtained by Diffusion Bonding Technique
Authors: Lebaili Abdelatif , Taouinet Mustapha , Lebaili Soltane
Published: September 2019

A dissimilar metal joining method based on diffusion bonding was developed to join 304L stainless steel (SS) and Zr alloy (Zy-4). This was done at 820°C and 950°C under argon and dynamic pressure for 45 minutes.The metallurgical structure of the interface and the evolution of its texture during the treatment were studied by evaluating the distribution of the constituent chemical elements and by identifying the crystalline phases formed. Chemical exchanges through the interface are favored by diffusion phenomena. The junction was characterized by: microscopic observations and chemical analyzes (ESEM-EDS, EPMA), X-RD and mechanical tests (HV and Shear test). Treatment at 820°C does not form a bond because the reciprocal solubilities of the chemical elements of SS and Zy-4 are very low. The junction obtained at 950°C has a reaction zone (RZ) formed at the SS/Zy-4 interface, composed of three layers. The first layer (LI = α-(Fe,Cr) on the SS side and the third layer (LIII=Zr2(Fe, Ni)) on the Zy-4 side are single-phased. The middle layer LII is biphasic (LII= e-Zr(Cr,Fe)2+Zr2(Fe, Ni)). The maximum hardness measured in the RZ is ~ 1120 HV. It is due to the formation of the intermetallic compounds of type e-Zr(Cr,Fe)2 in LII. Examination of fracture facies obtained from the joints reveals that the fracture is localized in the LIII layer and it is fragile in nature of the trans-granular type.
Influence of Cellulosic Fluxes on the Chemical Composition, Microstructure, Inclusions and Micro-Hardness of SMAW Multi-Pass Welds of X42 Steel
Authors: Khamouli Farida , Zidani Mosbah , Digheche Kaltoum , Saoudi Adel , Atoui L'Hadi
Published: September 2019

This paper studied the influence of cellulosic flux on the chemical composition, microstructure, formation of inclusions and micro hardness of X42 welded steel. The chemical compositions of the used fluxes are FA: E6010 and FB: E8010-P1, with electrodes has low carbon content. The welding conditions are not constant. The fluxes (FA and FB) have a high content of TiO2and SiO2and a low Ti and Si content was also detected in the internal (P1) and external (P3) passes. But there was an increase in the Ti content in the fusion zone (P1, P2 and P3) of the different passes gradually, compared to the base metal. The microstructure of the fusion zone (P1, P2 and P3) for each flux is mainly composed of acicular ferrite. The mass concentration variation of Mn is more elevated through the centers of the fusion zone passes (P1, P2 and P3) with the used fluxes. White and black non-metallic inclusions are observed, regardless of used flux. The micro-hardness in fusion zone varies according to the variation of the equivalent carbon in the different electrodes.
Kinematic analysis of rotary harrows
Authors: Raparelli Terenziano , Eula Gabriella , Ivanov Alexandre , Pepe Giuseppe
Published: September 2019

This article presents the kinematic analysis of the tine motion of a rotary harrow. In particular, it analyses the trajectories that the tines describe when they are pulled by the motion of the tractor and rotated by the rotors. This analysis, has led to the identification of the parameters that influence the motion of the tines and how these parameters intervene in the secondary tillage. The interaction between the tines and the soil is evaluated considering a plastic soil, i.e. without any cleavage and its propagation. With this hypothesis, the dimensions of the soil clods created by the passage of the tines in the soil have been analysed. The trajectories described by the tines of the machine, and therefore the dimensions of the portions of worked or unworked soil, are influenced by the operating parameters of the soil tillage process, such as the tractor speed and the angular speed of the tines themselves. Furthermore, a contribution is also given by the geometric parameters of the machine, such as the rotor radius and the geometric configuration of the rotary harrow in terms of rotor arrangement. This study is based on the creation of a mathematical model of the trajectories of the tines of a rotary harrow during soil tillage. The model is parametric and makes it possible to simulate and optimise the tillage process. The approach adopted also makes it possible to visualise the trajectories in graphic form for an easy visual interpretation of the results.
Financial management roles of nurse managers in selected public hospitals in KwaZulu-Natal province, South Africa
Authors: Naranjee Nellie , Ngxongo Thembelihle S.P. , Sibiya Maureen N.
Published: September 2019

Background: The public health sector in South Africa has been facing severe financial cutbacks and financial constraints in recent times. The nurse manager (NM) is faced with the task of managing and reducing expenditure in the nursing sector without compromising the quality care. This requires skills and understanding of financial management.Aim: This study aimed to explore the financial management roles of NMs and to identify financial management development needs necessary for NMs’ practice.Setting: The study was conducted in KwaZulu-Natal. A total of eight hospitals from the five health districts were included.Methods: The study used the naturalistic paradigm with a constructivist grounded theory approach. Interviews were used to initially gather data from six NMs who were purposively selected. Theoretical sampling was used to further recruit financial managers, chief executive officers, assistant nurse managers and operational managers. The final sample consisted of 18 participants.Results: Financial management of the hospitals is the primary function of the financial managers and the chief executive officers. However, the role of NMs extends to the performance and participation in various activities relating to the financial functioning of the hospital. These include financial planning, financial monitoring, financial decision-making and financial control.Conclusion: Nurse managers have a financial management function in public health care organisations but lack the necessary skills, knowledge and competencies to function in this role and require additional training. Recommendations included that a competency framework be developed to improve the financial management competencies of NMs.
The Effect of Dutasteride and Tomato Extract Combination on Reducing Blood Loss after Transurethral Resection of the Prostate
Authors: Nugroho Eriawan Agung , Kemara Selly Adyta , Amarwati Siti , Supit Tommy
Published: September 2019

Context:

Lycopene, a carotenoid found in tomatoes, possesses antiangiogenic activities that might be useful in the management of prostate enlargement. However, the current evidence is still inconclusive in regard to this matter.

Aims:

The aim of the study was to investigate the effect of combined oral dutasteride and lycopene consumption in reducing posttransurethral resection of the prostate (TURP) bleeding.

Settings and Design:

Twenty-two individuals diagnosed with benign prostatic hyperplasia were randomly allocated into two groups of equal size. Thirty days prior to TURP, individuals in Group 1 (control) were given daily oral dutasteride 0.5 mg and placebo pill and individuals in Group 2 (intervention) were given dutasteride 0.5 mg and lycopene 30 mg.

Subjects and Methods:

The parameters measured in this study were pre- and post-TURP plasma erythrocyte count and microvessel density (MVD) of resected prostate tissue stained with CD34.

Statistical Analysis Used:

Data homogeneity was tested using the Shapiro–Wilk test. Individuals' characteristics were analyzed using the Mann–Whitney U-test and plasma erythrocyte and MVD analyzed using the t-test. Spearman's correlation analysis was performed to find significant correlations between the two variables.

Results:

There were two dropouts. The mean MVD in the control group was significantly higher compared to the intervention group (28.2 ± 12.3 vs. 18.3 ± 7.6 vessel/mm2, P = 0.044). Reduction of post-TURP plasma erythrocytes was significantly higher in the control group compared to the intervention group (−0.34 ± 0.18 vs. −0.17 ± 0.12 106/μL, P = 0.048).

Conclusions:

Daily consumption of dutasteride and lycopene for at least 30 days reduced the formation of blood vessels in the prostate and reduced blood loss post-TURP.
Triviality Properties of Principal Bundles on Singular Curves. II
Authors: Belkale P. , Fakhruddin N.
Published: September 2019

For $G$ a split semi-simple group scheme and $P$ a principal $G$-bundle on a relative curve $X\rightarrow S$, we study a natural obstruction for the triviality of $P$ on the complement of a relatively ample Cartier divisor $D\subset X$. We show, by constructing explicit examples, that the obstruction is nontrivial if $G$ is not simply connected, but it can be made to vanish by a faithfully flat base change, if $S$ is the spectrum of a dvr (and some other hypotheses). The vanishing of this obstruction is shown to be a sufficient condition for étale local triviality if $S$ is a smooth curve, and the singular locus of $X-D$ is finite over $S$.
Highest weights for truncated shifted Yangians and product monomial crystals
Authors: Kamnitzer Joel , Tingley Peter , Webster Ben , Weekes Alex , Yacobi Oded
Published: September 2019

Truncated shifted Yangians are a family of algebras which are natural quantizations of slices in the affine Grassmannian.We study the highest weight representations of these algebras. In particular, we conjecture that the possible highest weights for these algebras are described by product monomial crystals, certain natural subcrystals of Nakajima’s monomials.We prove this conjecture in type A. We also place our results in the context of symplectic duality and prove a conjecture of Hikita in this situation.
Development of Multi-Material Overhead Stowage Systems for Commercial Aircrafts by Using New Design and Production Methods
Authors: Fette Marc , Büttemeyer Holger , Krause Daniel , Fick Gunnar
Published: September 2019

Innovative, lightweight and cost-efficient aircraft components require the use of modern lightweight materials and efficient production technologies. A promising technology is the combination of chopped fiber Sheet Molding Compounds (SMC) and pre-impregnated, continuous fiber fabrics processed by single-stage compression molding. The so-called Hybrid SMC Technology obtains cost-efficiency as well as time-saving production of loaded and functional aircraft components. However, reliable design principles for components and computing methods for predicting the material behavior have to be developed for a use in aviation industry. Hence, this paper deals with the development of materials, fabrics, manufacturing processes and computing methods related to the Hybrid SMC Technology. Those developments are demonstrated and validated by the implementation of a lightweight multi-material overhead stowage compartment (OHSC) using new design approaches as well as assembly principles.
Numerical Analysis of a Cycloidal Rotor under Diverse Operating Conditions and Altitudes
Authors: Rami Mehdi Habibnia , Pascoa Jose
Published: September 2019

The current paper presents the numerical study of the downwash flowfield characteristics in a cycloidal rotor at close-ground altitudes. In an aircraft equipped with this kind of thruster, the downwash flow plays significant role in different flight modes. The interaction of this downwash jet with ground in effective altitudes is studied using CFD simulations in OpenFOAM. Several operating conditions such as pitching oscillation angles, rotation speeds and height levels are all considered in this work. The results declare that close-ground operating states affects the performance of cyclorotors. The vertical and horizontal forces of a single blade is also analyzed in a complete cycloid in different operating conditions. A lead and lag in maximum and minimum extremes of force curves of a single blade is obtained while being subjected to different functional conditions. The presented results highly support an active control methodology to be taken for both pitching oscillations and rotation speeds as essential strategy for operating at optimum state.
Electromagnetic Characteristic Comparison of Superconducting Synchronous Motor Characteristics for Electric Aircraft Propulsion Systems
Authors: Terao Yutaka , Ishida Yusuke , Ohsaki Hiroyuki , Oyori Hitoshi
Published: September 2019

This paper describes the comparison of electromagnetic characteristics of two different superconducting-motor structures for electrified aircraft propulsion systems. Future electrified aircraft demand higher output (over 16 kW/kg) and higher efficiency (> 98%) for their motors in comparison with current ones. To satisfy the demands, two kinds of superconducting motors are dealt in this study: one is partially superconducting motors (PSCMs), made of superconducting field coils and copper armature windings; the other is the fully superconducting motors (FSCMs) made of superconducting field/armature windings. They are cooled at 20 K with liquid hydrogen. We designed these two motors with finite element method to obtain the output density of 16-20 kW/kg for future electrified propulsion systems. We selected 3.0- and 5.0 MW superconducting motors, considering the application to aircraft for almost 180 passengers and 44 MW rated power for take-off. Also, we evaluated the motor weight using two kinds of cryostat materials: stainless steel (SUS) and fiber-reinforced plastic (FRP). The results show that the 5.0 MW PSCM using FRP achieved the output density of 16.9 kW/kg and the FSCMs with FRP of 23.5 kW/kg, respectively. The values of their output density are over three times higher than those of synchronous motors using permanent magnets, whose maximum output density value is 5 kW/kg, so far. We also evaluated the motor losses and efficiency; their results described that the efficiency of the PSCM achieved around 98%, while the 5.0 MW FSCM over 99%. The obtained data shows the superconducting motors are one of the key solutions to realize future electrified aircraft propulsion systems.
Building Multiple Resolution Modeling Systems Using the High-Level Architecture
Authors: Lee Gene , Kim Jaeho , Marin Mario , Lee Kyungeun , Gutierrez Edgar , Rabelo Luis
Published: September 2019

The modeling and simulation pyramid in defense states it clearly: Multi-Level modeling and simulation are required. Models and simulations are often classified by the US Department of Defense into four levels—campaign, mission, engagement, and engineering. Campaign simulation models are applied for evaluation; mission-level simulations to experiment with the integration of several macro agents; engagement simulations in engineered systems development; and engineering-level simulation models with a solid foundation in structural physics and components. Models operating at one level must be able to interact with models at another level. Therefore, the cure (“silver bullet”) is very clear: a comprehensive framework for Multiple Resolution Modeling (MRM) is needed.

In this paper, we discuss our research about how to construct MRM environments. Also, the utilization of the High-Level Architecture (HLA) is explained and in particular, the processes of verification and validation in these composite models. Three implementations in the areas of aerospace, navy ships, and infantry combat are utilized to illustrate the MRM simulation concepts.
Orbital Forming of Automotive Wheel Bearings
Authors: Sponsler Jake
Published: September 2019

Orbital forming is considered an optimal assembly process for many designs of automotive wheel bearing assemblies. More specifically, this process involves forming the spindle over the inner race of the wheel bearing to maximize surface area contact on the inner ring for retention, and to maintain bearing preload. The unique forming properties and precise controls allow orbital forming to produce an ideal finished retention feature and form for these types of bearings. This paper discusses the specific benefits of orbital forming of automotive wheel bearings. Forming basics, the physics behind the benefits of orbital forming, as well as pre-form lip geometry and other part design considerations are presented. Advanced machine control methodologies and historical machine process improvements are also reviewed concluding with next steps in process control and in-machine quality assurance.
Brati Plinija: O Pliniju starejšem, likovni umetnosti in metodi
Authors: Mahnič Katja
Published: September 2019

Sodobnemu bralcu se Plinijeva »poglavja o umetnosti« lahko zdijo presenetljivo domača. S svojim seznamom umetnikov in del, ki so urejena kot niz slogovnih iznajdb in izboljšav, Plinijev opis grške umetnosti ... v marsikaterem pogledu ustreza zdaj splošno uveljavljenemu modelu zgodovine umetnosti. Vzrok za to je seveda v dejstvu, da je Plinijevo besedilo igralo osrednjo vlogo pri razvoju tega modela (Carey, 2003, 13).