Abdoul‐Aziz Bogno, Henri Nguyen-Thi, N. Bergeon, Nathalie Mangelinck‐Noël, T. Schenk, B. Billia, E. Boller, J. Baruchel,
The phenomena involved during equiaxed growth, which is the most common growth morphology in metal casting, are dynamic. Therefore, in situ investigation is necessary to fully analyse the microstructure formation. Synchrotron X-ray radiography has become a major tool for in situ characterization of solidification in metallic systems. This paper reports on dedicated equiaxed solidification experiments carried out at the European Synchrotron Radiation Facility (ESRF) in Grenoble-France on Al–10 wt.% ...
Tópico(s): Metallurgy and Material Forming
2009 - Elsevier BV | Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms
Abdoul‐Aziz Bogno, H. Nguyen-Thi, B. Billia, N. Bergeon, Nathalie Mangelinck‐Noël, Élodie Boller, T. Schenk, J. Baruchel,
Tópico(s): Metallurgical Processes and Thermodynamics
2009 - Springer Science+Business Media | Transactions of the Indian Institute of Metals
A. Graue, E. Aspenes, Thomas Bognø, R. Moe, J Ramsdal,
This paper emphasizes how wettability may be altered for special core analysis purposes and by which processes this occurs. Studies of how the imbibition characteristics change after aging core plugs in crude oil are reported, focusing on imbibition rate and endpoint saturations and on the induction time. Imbibition characteristics after wettability alteration by aging core plugs submerged in crude oil at elevated temperature are compared to the effects from aging procedures, where crude oil is ...
Tópico(s): Reservoir Engineering and Simulation Methods
2002 - Elsevier BV | Journal of Petroleum Science and Engineering
B. Billia, Henri Nguyen-Thi, Nathalie Mangelinck‐Noël, N. Bergeon, Hyejin Jung, G. Reinhart, Abdoul‐Aziz Bogno, Adeline Buffet, J. Härtwig, J. Baruchel, T. Schenk,
The microstructure formed during the solidification step has a major influence on the properties of materials processed by major techniques (casting, welding ...). In situ and real-time characterization by synchrotron X-ray imaging is the method of choice to unveil the dynamical formation of the solidification microstructure in metallic alloys, and thus provide precise data for the critical validation of the theoretical predictions that is needed for sound advancement of modeling and numerical simulation. ...
Tópico(s): Metallurgical Processes and Thermodynamics
2010 - The Iron and Steel Institute of Japan | ISIJ International
Adeline Buffet, Henri Nguyen-Thi, Abdoul‐Aziz Bogno, T. Schenk, Nathalie Mangelinck‐Noël, G. Reinhart, N. Bergeon, B. Billia, J. Baruchel,
In the present study, we report on an image analysis procedure, which enables to extract from synchrotron radiographs the long range solute profiles in the whole sample and in both phases (solid and liquid). This image analysis is based on the measurement of local density differences, and is applied to study the directional solidification of Al - 4wt% Cu alloy, from planar to onset of the initial instability. Dedicated experiments were carried out at the European Synchrotron Radiation Facility (ESRF) ...
Tópico(s): Metallurgical Processes and Thermodynamics
2010 - Trans Tech Publications | Materials science forum
Abdoul‐Aziz Bogno, G. Reinhart, Adeline Buffet, H. Nguyen Thi, B. Billia, T. Schenk, Nathalie Mangelinck‐Noël, N. Bergeon, J. Baruchel,
We report on in situ study of the initial transient during planar solidification of an Al–4 wt%Cu alloy by means of synchrotron X-ray radiography. Based on the recorded X-ray images, we first analysed in detail the time evolution of the macroscopic deformation of the solid-liquid interface. This deformation is due to the convective flow in the melt initiated by a residual transverse temperature gradient, and amplified by the solute rejection during solidification process. Additionally the growth ...
Tópico(s): Metallurgical Processes and Thermodynamics
2010 - Elsevier BV | Journal of Crystal Growth
Henri Nguyen-Thi, Abdoul‐Aziz Bogno, G. Reinhart, B. Billia, Ragnvald H. Mathiesen, G. Zimmermann, Y. Houltz, Kenneth Löth, D. Voss, Antonio Verga, Fabio De Pascale,
As most of the phenomena involved during solidification are dynamic, in situ and real-time X-ray imaging should be retained as the method of choice for investigating the solidification front evolution of metallic alloys grown from the melt. On Earth, natural convection in the melt is well known to be the major source of various disturbing effects which can significantly modify or mask important physical mechanisms. Microgravity environment is an efficient way to eliminate buoyancy and convection ...
Tópico(s): Crystallization and Solubility Studies
2011 - IOP Publishing | Journal of Physics Conference Series
Yun Chen, Abdoul‐Aziz Bogno, Na Xiao, B. Billia, Xiu Hong Kang, Henri Nguyen-Thi, Xing Hong Luo, Dian Zhong Li,
The initial transient during directional solidification of an Al–4 wt.% Cu alloy was simulated by a quantitative phase-field model solved with the adaptive finite element method. The simulated solidification process was compared with the related analytical theory and in situ and real time observations by means of X-ray radiography at the European Synchrotron Radiation Facility. The simulated velocity of the planar interface and solute profile ahead of the solidification front in the liquid are close ...
Tópico(s): Metallurgical Processes and Thermodynamics
2011 - Elsevier BV | Acta Materialia
Abdoul‐Aziz Bogno, Henri Nguyen-Thi, Adeline Buffet, G. Reinhart, B. Billia, Nathalie Mangelinck‐Noël, N. Bergeon, J. Baruchel, T. Schenk,
In situ monitoring of the initial transient of directional solidification was carried out by means of synchrotron X-ray radiography. Experiments with Al–4 wt.% Cu alloy samples were performed on beamline ID19 of the European Synchrotron Radiation Facility (ESRF) in a dedicated Bridgman-type furnace. X-ray radiography enabled a detailed analysis of the evolution over time of the solid–liquid interface macroscopic shape in interaction with convection in the melt. Lateral solute segregation induced ...
Tópico(s): Aluminum Alloy Microstructure Properties
2011 - Elsevier BV | Acta Materialia
Abdoul‐Aziz Bogno, Henri Nguyen-Thi, G. Reinhart, B. Billia, J. Baruchel,
This paper addresses dendritic equiaxed growth during grain structure formation in alloy solidification, and focuses on the growth and interaction of primary dendrite arms, which drive and limit grain development, respectively. Dedicated solidification experiments on Al–10 wt.% Cu alloy were carried out at the European Synchrotron Radiation Facility, enabling live observation by in situ and real-time synchrotron X-ray radiography. Equiaxed solidification was achieved by cooling nearly isothermal ...
Tópico(s): Metallurgy and Material Forming
2012 - Elsevier BV | Acta Materialia
Yun Chen, B. Billia, Dian Zhong Li, Henri Nguyen-Thi, Na Xiao, Abdoul‐Aziz Bogno,
The evolution of the solid–liquid interface morphology during the initial transient of directional solidification is investigated by quantitative phase-field numerical simulation during cooling down of an Al–4 wt.% Cu alloy growing in the preferred 〈1 0 0〉-direction. Simulations show that the shape of the non-planar solid–liquid interface varies with the instantaneous growth parameters; in particular, above a critical value of tip velocity, cell/dendrite tips undergo Mullins–Sekerka morphological ...
Tópico(s): Metallurgical Processes and Thermodynamics
2014 - Elsevier BV | Acta Materialia
A. Graue, Thomas Bognø, Bernard A. Baldwin, Eugene A. Spinler,
Summary Iterative comparison between experimental work and numerical simulations has been used to predict oil-recovery mechanisms in fractured chalk as a function of wettability. Selective and reproducible alteration of wettability by aging in crude oil at an elevated temperature produced chalk blocks that were strongly water-wet and moderately water-wet, but with identical mineralogy and pore geometry. Large scale, nuclear-tracer, 2D-imaging experiments monitored the waterflooding of these blocks ...
Tópico(s): Hydrocarbon exploration and reservoir analysis
2001 - | SPE Reservoir Evaluation & Engineering
Produção Nacional
Revisado por pares
Abdoul‐Aziz Bogno, José Eduardo Spinelli, Conrado Ramos Moreira Afonso, H. Henein,
The properties and performance of lead-free solder alloys such as fluidity and wettability are defined by the alloy composition and solidification microstructure. Rapid solidification of metallic alloys is known to result in refined microstructures with reduced microsegregation and improved mechanical properties of the final products as compared to normal castings. The rapidly solidified Sn-based solders by melt spinning were shown to be suitable for soldering with low temperature and short soldering ...
Tópico(s): Aluminum Alloy Microstructure Properties
2015 - Elsevier BV | Journal of Materials Research and Technology
Marie Bedel, G. Reinhart, Abdoul‐Aziz Bogno, Charles‐André Gandin, S. Jacomet, Élodie Boller, Henri Nguyen-Thi, H. Henein,
The impulse atomization process developed at the University of Alberta (Canada) enables metallic powders to be solidified with well controlled process parameters. The inner microstructure of several droplets of Al–4.5 wt.%Cu alloy produced by this technique has been investigated by using both synchrotron X-ray micro-tomography and electron backscattered diffraction (EBSD). The 3D reconstructions obtained by micro-tomography are used to visualize cross sections of the droplets in any spatial directions. ...
Tópico(s): Metallurgical Processes and Thermodynamics
2015 - Elsevier BV | Acta Materialia
Abdoul‐Aziz Bogno, P. Delshad Khatibi, H. Henein, Charles‐André Gandin,
Tópico(s): Metallurgical Processes and Thermodynamics
2016 - Springer Science+Business Media | Metallurgical and Materials Transactions A
Bachirou Bogno, Jean-Paul Sawicki, Chafic Salame, Michel Aillerie, Fréderic Saint-Eve, Oumarou Hamandjoda, Tibi Béda,
In a renewable energy system, in order to ensure continuous production, batteries associated to a charge controller are always necessary whenever the source of charging is solar, wind, or hydraulics. For photovoltaic (PV) systems, an excessive energy produced by solar cells during intense sunlight peak conditions could damage the batteries. A charge controller is therefore used to maintain the suitable charging voltage to the batteries so that, as the input voltage from the PV module rises, the charge ...
Tópico(s): Advancements in Battery Materials
2016 - Elsevier BV | International Journal of Hydrogen Energy
Torvid Kiserud, Knut Gjelland, H. Bognø, M. Waardal, Hallvard Reigstad, Karen Rosendahl,
Abstract The presence of echogenic material within the gallbladder is probably a rare finding in the fetus, and the list of predisposing factors known for postnatal life seems not to be applicable to prenatal diagnosis. In the present study 1656 obstetric scans were performed on referrals to the Unit of Fetal Medicine. No echogenic gallbladder contents were found before 28 weeks. In the subgroup of 523 fetuses who were examined during gestational weeks 28–42, six fetuses were found to have echogenic ...
Tópico(s): Congenital Anomalies and Fetal Surgery
1997 - Wiley | Ultrasound in Obstetrics and Gynecology
Produção Nacional
Revisado por pares
José Eduardo Spinelli, Abdoul‐Aziz Bogno, H. Henein,
Tópico(s): Microstructure and mechanical properties
2017 - Springer Science+Business Media | Metallurgical and Materials Transactions A
Elie Bertrand Kengne Signe, Bachirou Bogno, Michel Aillerie, Oumarou Hamandjoda,
Currently in the world, the development of renewable energy appears as a relevant contribution fighting against the climate change. Micro hydro power plants (MHPP) are an excellent method of harnessing renewable energy. Cameroon has lots of small waterfalls suitable for the development of MHPP. But, their development is not yet effective because of the lack of data and technology skills. The objective of this work is to develop and propose a software tool for the feasibility studies of MHPP in Cameroon, ...
Tópico(s): Oil and Gas Production Techniques
2019 - Elsevier BV | Energy Procedia
William Hearn, Abdoul‐Aziz Bogno, José Eduardo Spinelli, J. Valloton, H. Henein,
Tópico(s): Aluminum Alloys Composites Properties
2019 - Springer Science+Business Media | Metallurgical and Materials Transactions A
Dieudonné Kaoga Kidmo, Kodji Deli, Bachirou Bogno,
Globally, the continuous increase of energy consumption coupled with the depletion of the limited fossil fuel sources and their negative impacts on the environment, has shifted focus towards renewables for a sustainable development. For the last fifteen years, the world has enjoyed renewables generation capacity increases in a double-digit Terawatt-hours range. Although renewables consumption is fast developing in Asia Pacific, Europe and North America, significant coordination efforts are required ...
Tópico(s): Social Acceptance of Renewable Energy
2021 - EDP Sciences | Renewable Energy and Environmental Sustainability
Xiuhui Li, Morteza Ghasri-Khouzani, Abdoul‐Aziz Bogno, Jing Liu, H. Henein, Zengtao Chen, Ahmed Jawad Qureshi,
This study reports fabrication, mechanical characterization, and finite element modeling of a novel lattice structure based bimetallic composite comprising 316L stainless steel and a functional dissolvable aluminum alloy. A net-shaped 316L stainless steel lattice structure composed of diamond unit cells was fabricated by selective laser melting (SLM). The cavities in the lattice structure were then filled through vacuum-assisted melt infiltration to form the bimetallic composite. The bulk aluminum ...
Tópico(s): Additive Manufacturing and 3D Printing Technologies
2021 - Multidisciplinary Digital Publishing Institute | Materials
Morteza Ghasri-Khouzani, X. Li, Abdoul‐Aziz Bogno, Zhijiang Chen, Jingao Liu, H. Henein, Ahmed Jawad Qureshi,
This paper provides a hybrid method for net shape, lattice based, complex bimetallic composites using a combination of laser powder bed additive manufacturing and vacuum-assisted melt infiltration casting process. 316L stainless steel lattice structures were built using a selective laser melting (SLM) technique. Then, their cavities were filled with an aluminum alloy using vacuum-assisted melt infiltration to yield a bimetallic composite. For comparison purposes, monolithic aluminum alloy was also ...
Tópico(s): Cellular and Composite Structures
2021 - Elsevier BV | Journal of Manufacturing Processes
Federico Piccioni, Luigi Mariani, Lucia Bogno, Ilaria Rivetti, Giulia T. A. Tramontano, Marco Carbonara, Mario Ammatuna, Martin Langer,
This randomized double-blind study was designed to determine if respiratory muscle weakness – measured by maximum inspiratory pressure (MIP), maximum expiratory pressure (MEP), forced vital capacity (FVC), and forced expiratory volume in one second (FEV1) – persists even if an acceleromyographic train-of-four ratio (TOFR) of 1.0 is reached after major abdominal surgery. Twenty patients underwent respiratory function tests before induction of anesthesia. Rocuronium was given, and the tests were repeated after ...
Tópico(s): Intensive Care Unit Cognitive Disorders
2014 - Springer Science+Business Media | Canadian Journal of Anesthesia/Journal canadien d anesthésie
Yun Chen, Abdoul‐Aziz Bogno, B. Billia, Xiu Hong Kang, Henri Nguyen-Thi, Dian Zhong Li, Xing Hong Luo, Jean‐Marc Debierre,
The initial transient in directional solidification of Al–4wt%Cu alloy by cooling-down is investigated by numerical simulation using the phase-field model proposed by Karma (Phys. Rev. Lett., 87 (2001) 115701), which includes solute antitrapping in mass conservation relation and is solved by the adaptive finite element method. The simulated velocity of the unsteady planar solidification interface and the solute profile in the liquid are always close to the predictions of the Warren–Langer analytical ...
Tópico(s): Metallurgical Processes and Thermodynamics
2010 - The Iron and Steel Institute of Japan | ISIJ International
Dieudonné Kidmo Kaoga, Bachirou Bogno, Michel Aillerie, Danwé Raïdandi, Serge Doka Yamigno, Oumarou Hamandjoda, Tibi Béda,
In this work, 28 years of wind data, measured at 10m above ground level (AGL), from Maroua meteorological station is utilized to assess the potential of wind energy at exposed ridges tops of mountains surrounding the city of Maroua. The aim of this study is to estimate the cost of wind-generated electricity using six types of wind turbines (50 to 2000 kW). The Weibull distribution function is employed to estimate Weibull shape and scale parameters using the energy pattern factor method. The considered ...
Tópico(s): Solar Radiation and Photovoltaics
2016 - American Institute of Physics | AIP conference proceedings
Yun Chen, Henri Nguyen-Thi, Dian Zhong Li, Abdoul‐Aziz Bogno, B. Billia, Na Xiao,
The influence of natural convection on the evolution of the solid-liquid (s/l) interface during the initial transient of upward directional solidification was studied on Al-4 wt.% Cu alloy by coupling the two dimensional quantitative phase-field model with the Navier-Stokes equations. The simulations were compared with in situ and real-time synchrotron X-ray monitoring data. The origin of natural convection in experiment was the presence of a small unavoidable horizontal temperature gradient. Due ...
Tópico(s): Metallurgical Processes and Thermodynamics
2012 - IOP Publishing | IOP Conference Series Materials Science and Engineering
Bachirou Bogno, Sali Mohammadou, Michel Aillerie,
This paper reports on a technical and economic evaluation of an autonomous wind system for domestic electricity generation to be used in a secondary school located in a Sahel zone of central Africa. Indeed, development and application of renewable resources are very common in the industrialized countries as well as in some of the so-called third-world countries. With regard to Cameroon, this large country is characterized by a much-diversified climate and two distinct geographical zones, an equatorial ...
Tópico(s): Hybrid Renewable Energy Systems
2014 - Elsevier BV | Energy Procedia
Bachirou Bogno, Sali Mohammadou, Michel Aillerie,
This paper analyzes and evaluates the possible technical and economical optimization of electricity production by autonomous hybrid power generator from renewable sources integrating an electrochemical storage system. A progressive combination of wind-turbines to photovoltaic modules is carried out in order to minimize the size of the electrochemical storage system over the cost of the resulting autonomous generator. An autonomous system with solar PV is dimensioned with respect to the needs in ...
Tópico(s): Electric Vehicles and Infrastructure
2015 - Elsevier BV | Energy Procedia
Aminou Halidou, Xinge You, Bachirou Bogno,
Nowadays pedestrian detection plays an important role in security and driving assistance. Detecting moving object is complex, and some of the detection methods are comparatively ineffective and slow. In relation to human detection it is very useful to combine independent information sources, such as appearance and motion. To achieve acceptable detection performance, we propose inter-frames differencing image to compute the region of interest, and MB-BIF to extract features. The MB-BIF approach combines ...
Tópico(s): Advanced Neural Network Applications
2014 - Canadian Center of Science and Education | Computer and Information Science