The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Olivier Spalla - One of the best experts on this subject based on the ideXlab platform.
-
Behavior and determination of titanium dioxide nanoparticles in nitric acid and river water by ICP spectrometry.
Analytical chemistry, 2014Co-Authors: Valérie Geertsen, Michel Tabarant, Olivier SpallaAbstract:ICP spectrometry (ICPMS, ICPOES) are classical techniques for the determination of solubilized or suspended elements. Unfortunately, their relevance for nanoparticles at low concentration (below 10 ppm) is rarely called into question, even if literature reports are not always coherent. This work is a systematic study based on the measurement of TiO2 nanoparticle suspensions, as a model of quasi-insoluble material, by plasma spectrometry. It studies both sample treatment and measurement in the 10 ppb to 30 ppm concentration range. Realized on a set of four engineered nanoparticles suspensions at low concentration, it shows the existence of three different regimes of stability that affect concentration measurement. Above a CS stability concentration value, suspensions are stable in time; below a low-concentration CE value, the signal loss is at a maximum, and a Final Partition is reached between the container walls and the suspension. Between these two regimes, the suspension aging varies with concentration...
-
Behavior and Determination of Titanium Dioxide Nanoparticles in Nitric Acid and River Water by ICP Spectrometry
Analytical Chemistry, 2014Co-Authors: Valérie Geertsen, Michel Tabarant, Olivier SpallaAbstract:ICP spectrometry (ICPMS, ICPOES) are classical techniques for the determination of solubilized or suspended elements. Unfortunately, their relevance for nanoparticles at low concentration (below 10 ppm) is rarely called into question, even if literature reports are not always coherent. This work is a systematic study based on the measurement of TiO2 nanoparticle suspensions, as a model of quasi-insoluble material, by plasma spectrometry. It studies both sample treatment and measurement in the 10 ppb to 30 ppm concentration range. Realized on a set of four engineered nanoparticles suspensions at low concentration, it shows the existence of three different regimes of stability that affect concentration measurement. Above a CS stability concentration value, suspensions are stable in time; below a low-concentration CE value, the signal loss is at a maximum, and a Final Partition is reached between the container walls and the suspension. Between these two regimes, the suspension aging varies with concentration. CE and CS depend on nanoparticle characteristics and the suspension medium, whereas the evolution kinetic is volume-dependent. Because TiO2 nanoparticles are present in the environment at concentrationd below CS, it is then necessary to find a way to rehomogenize the suspension between sampling and analyzing. Soft sonication, minimizing the sample temperature, and trapping of free radicals is proposed and evaluated. Homogenization is traced by the addition of an internal standard before storage. The procedure is applied to a real sample, Seine River water. The amount of total titanium found, 48.7 ppb, is in good agreement with the result of the reference method.
Valérie Geertsen - One of the best experts on this subject based on the ideXlab platform.
-
Behavior and determination of titanium dioxide nanoparticles in nitric acid and river water by ICP spectrometry.
Analytical chemistry, 2014Co-Authors: Valérie Geertsen, Michel Tabarant, Olivier SpallaAbstract:ICP spectrometry (ICPMS, ICPOES) are classical techniques for the determination of solubilized or suspended elements. Unfortunately, their relevance for nanoparticles at low concentration (below 10 ppm) is rarely called into question, even if literature reports are not always coherent. This work is a systematic study based on the measurement of TiO2 nanoparticle suspensions, as a model of quasi-insoluble material, by plasma spectrometry. It studies both sample treatment and measurement in the 10 ppb to 30 ppm concentration range. Realized on a set of four engineered nanoparticles suspensions at low concentration, it shows the existence of three different regimes of stability that affect concentration measurement. Above a CS stability concentration value, suspensions are stable in time; below a low-concentration CE value, the signal loss is at a maximum, and a Final Partition is reached between the container walls and the suspension. Between these two regimes, the suspension aging varies with concentration...
-
Behavior and Determination of Titanium Dioxide Nanoparticles in Nitric Acid and River Water by ICP Spectrometry
Analytical Chemistry, 2014Co-Authors: Valérie Geertsen, Michel Tabarant, Olivier SpallaAbstract:ICP spectrometry (ICPMS, ICPOES) are classical techniques for the determination of solubilized or suspended elements. Unfortunately, their relevance for nanoparticles at low concentration (below 10 ppm) is rarely called into question, even if literature reports are not always coherent. This work is a systematic study based on the measurement of TiO2 nanoparticle suspensions, as a model of quasi-insoluble material, by plasma spectrometry. It studies both sample treatment and measurement in the 10 ppb to 30 ppm concentration range. Realized on a set of four engineered nanoparticles suspensions at low concentration, it shows the existence of three different regimes of stability that affect concentration measurement. Above a CS stability concentration value, suspensions are stable in time; below a low-concentration CE value, the signal loss is at a maximum, and a Final Partition is reached between the container walls and the suspension. Between these two regimes, the suspension aging varies with concentration. CE and CS depend on nanoparticle characteristics and the suspension medium, whereas the evolution kinetic is volume-dependent. Because TiO2 nanoparticles are present in the environment at concentrationd below CS, it is then necessary to find a way to rehomogenize the suspension between sampling and analyzing. Soft sonication, minimizing the sample temperature, and trapping of free radicals is proposed and evaluated. Homogenization is traced by the addition of an internal standard before storage. The procedure is applied to a real sample, Seine River water. The amount of total titanium found, 48.7 ppb, is in good agreement with the result of the reference method.
Michel Tabarant - One of the best experts on this subject based on the ideXlab platform.
-
Behavior and determination of titanium dioxide nanoparticles in nitric acid and river water by ICP spectrometry.
Analytical chemistry, 2014Co-Authors: Valérie Geertsen, Michel Tabarant, Olivier SpallaAbstract:ICP spectrometry (ICPMS, ICPOES) are classical techniques for the determination of solubilized or suspended elements. Unfortunately, their relevance for nanoparticles at low concentration (below 10 ppm) is rarely called into question, even if literature reports are not always coherent. This work is a systematic study based on the measurement of TiO2 nanoparticle suspensions, as a model of quasi-insoluble material, by plasma spectrometry. It studies both sample treatment and measurement in the 10 ppb to 30 ppm concentration range. Realized on a set of four engineered nanoparticles suspensions at low concentration, it shows the existence of three different regimes of stability that affect concentration measurement. Above a CS stability concentration value, suspensions are stable in time; below a low-concentration CE value, the signal loss is at a maximum, and a Final Partition is reached between the container walls and the suspension. Between these two regimes, the suspension aging varies with concentration...
-
Behavior and Determination of Titanium Dioxide Nanoparticles in Nitric Acid and River Water by ICP Spectrometry
Analytical Chemistry, 2014Co-Authors: Valérie Geertsen, Michel Tabarant, Olivier SpallaAbstract:ICP spectrometry (ICPMS, ICPOES) are classical techniques for the determination of solubilized or suspended elements. Unfortunately, their relevance for nanoparticles at low concentration (below 10 ppm) is rarely called into question, even if literature reports are not always coherent. This work is a systematic study based on the measurement of TiO2 nanoparticle suspensions, as a model of quasi-insoluble material, by plasma spectrometry. It studies both sample treatment and measurement in the 10 ppb to 30 ppm concentration range. Realized on a set of four engineered nanoparticles suspensions at low concentration, it shows the existence of three different regimes of stability that affect concentration measurement. Above a CS stability concentration value, suspensions are stable in time; below a low-concentration CE value, the signal loss is at a maximum, and a Final Partition is reached between the container walls and the suspension. Between these two regimes, the suspension aging varies with concentration. CE and CS depend on nanoparticle characteristics and the suspension medium, whereas the evolution kinetic is volume-dependent. Because TiO2 nanoparticles are present in the environment at concentrationd below CS, it is then necessary to find a way to rehomogenize the suspension between sampling and analyzing. Soft sonication, minimizing the sample temperature, and trapping of free radicals is proposed and evaluated. Homogenization is traced by the addition of an internal standard before storage. The procedure is applied to a real sample, Seine River water. The amount of total titanium found, 48.7 ppb, is in good agreement with the result of the reference method.
Guillaume Houzeaux - One of the best experts on this subject based on the ideXlab platform.
-
Parallel SFC-based mesh Partitioning and load balancing
arXiv: Computational Physics, 2020Co-Authors: R. Borrell, Guillermo Oyarzun, Damien Dosimont, Guillaume HouzeauxAbstract:Modern supercomputers allow the simulation of complex phenomena with increased accuracy. Eventually, this requires finer geometric discretizations with larger numbers of mesh elements. In this context, and extrapolating to the Exascale paradigm, meshing operations such as generation, adaptation or Partition, become a critical bottleneck within the simulation workflow. In this paper, we focus on mesh Partitioning. In particular, we present some improvements carried out on an in-house parallel mesh Partitioner based on the Hilbert Space-Filling Curve. Additionally, taking advantage of its performance, we present the application of the SFC-based Partitioning for dynamic load balancing. This method is based on the direct monitoring of the imbalance at runtime and the subsequent re-Partitioning of the mesh. The target weights for the optimized Partitions are evaluated using a least-squares approximation considering all measurements from previous iterations. In this way, the Final Partition corresponds to the average performance of the computing devices engaged.
-
parallel sfc based mesh Partitioning and load balancing
2019 IEEE ACM 10th Workshop on Latest Advances in Scalable Algorithms for Large-Scale Systems (ScalA), 2019Co-Authors: R. Borrell, Guillermo Oyarzun, Damien Dosimont, Guillaume HouzeauxAbstract:Modern supercomputers allow the simulation of complex phenomena with increased accuracy. Eventually, this requires finer geometric discretizations with larger numbers of mesh elements. In this context, and extrapolating to the Exascale paradigm, meshing operations such as generation, adaptation or Partition, become a critical issue within the simulation workflow. In this paper, we focus on mesh Partitioning. In particular, we present some improvements carried out on an in-house parallel mesh Partitioner based on the Hilbert Space-Filling Curve. Additionally, taking advantage of its performance, we present the application of the SFC-based Partitioning for dynamic load balancing. This method is based on the direct monitoring of the imbalance at runtime and the subsequent re-Partitioning of the mesh. The target weights for the optimized Partitions are evaluated using a least-squares approximation considering all measurements from previous iterations. In this way, the Final Partition corresponds to the average performance of the computing devices engaged.
-
ScalA@SC - Parallel SFC-based mesh Partitioning and load balancing
2019 IEEE ACM 10th Workshop on Latest Advances in Scalable Algorithms for Large-Scale Systems (ScalA), 2019Co-Authors: R. Borrell, Guillermo Oyarzun, Damien Dosimont, Guillaume HouzeauxAbstract:Modern supercomputers allow the simulation of complex phenomena with increased accuracy. Eventually, this requires finer geometric discretizations with larger numbers of mesh elements. In this context, and extrapolating to the Exascale paradigm, meshing operations such as generation, adaptation or Partition, become a critical issue within the simulation workflow. In this paper, we focus on mesh Partitioning. In particular, we present some improvements carried out on an in-house parallel mesh Partitioner based on the Hilbert Space-Filling Curve. Additionally, taking advantage of its performance, we present the application of the SFC-based Partitioning for dynamic load balancing. This method is based on the direct monitoring of the imbalance at runtime and the subsequent re-Partitioning of the mesh. The target weights for the optimized Partitions are evaluated using a least-squares approximation considering all measurements from previous iterations. In this way, the Final Partition corresponds to the average performance of the computing devices engaged.
R. Borrell - One of the best experts on this subject based on the ideXlab platform.
-
Parallel SFC-based mesh Partitioning and load balancing
arXiv: Computational Physics, 2020Co-Authors: R. Borrell, Guillermo Oyarzun, Damien Dosimont, Guillaume HouzeauxAbstract:Modern supercomputers allow the simulation of complex phenomena with increased accuracy. Eventually, this requires finer geometric discretizations with larger numbers of mesh elements. In this context, and extrapolating to the Exascale paradigm, meshing operations such as generation, adaptation or Partition, become a critical bottleneck within the simulation workflow. In this paper, we focus on mesh Partitioning. In particular, we present some improvements carried out on an in-house parallel mesh Partitioner based on the Hilbert Space-Filling Curve. Additionally, taking advantage of its performance, we present the application of the SFC-based Partitioning for dynamic load balancing. This method is based on the direct monitoring of the imbalance at runtime and the subsequent re-Partitioning of the mesh. The target weights for the optimized Partitions are evaluated using a least-squares approximation considering all measurements from previous iterations. In this way, the Final Partition corresponds to the average performance of the computing devices engaged.
-
parallel sfc based mesh Partitioning and load balancing
2019 IEEE ACM 10th Workshop on Latest Advances in Scalable Algorithms for Large-Scale Systems (ScalA), 2019Co-Authors: R. Borrell, Guillermo Oyarzun, Damien Dosimont, Guillaume HouzeauxAbstract:Modern supercomputers allow the simulation of complex phenomena with increased accuracy. Eventually, this requires finer geometric discretizations with larger numbers of mesh elements. In this context, and extrapolating to the Exascale paradigm, meshing operations such as generation, adaptation or Partition, become a critical issue within the simulation workflow. In this paper, we focus on mesh Partitioning. In particular, we present some improvements carried out on an in-house parallel mesh Partitioner based on the Hilbert Space-Filling Curve. Additionally, taking advantage of its performance, we present the application of the SFC-based Partitioning for dynamic load balancing. This method is based on the direct monitoring of the imbalance at runtime and the subsequent re-Partitioning of the mesh. The target weights for the optimized Partitions are evaluated using a least-squares approximation considering all measurements from previous iterations. In this way, the Final Partition corresponds to the average performance of the computing devices engaged.
-
ScalA@SC - Parallel SFC-based mesh Partitioning and load balancing
2019 IEEE ACM 10th Workshop on Latest Advances in Scalable Algorithms for Large-Scale Systems (ScalA), 2019Co-Authors: R. Borrell, Guillermo Oyarzun, Damien Dosimont, Guillaume HouzeauxAbstract:Modern supercomputers allow the simulation of complex phenomena with increased accuracy. Eventually, this requires finer geometric discretizations with larger numbers of mesh elements. In this context, and extrapolating to the Exascale paradigm, meshing operations such as generation, adaptation or Partition, become a critical issue within the simulation workflow. In this paper, we focus on mesh Partitioning. In particular, we present some improvements carried out on an in-house parallel mesh Partitioner based on the Hilbert Space-Filling Curve. Additionally, taking advantage of its performance, we present the application of the SFC-based Partitioning for dynamic load balancing. This method is based on the direct monitoring of the imbalance at runtime and the subsequent re-Partitioning of the mesh. The target weights for the optimized Partitions are evaluated using a least-squares approximation considering all measurements from previous iterations. In this way, the Final Partition corresponds to the average performance of the computing devices engaged.