The Experts below are selected from a list of 27048 Experts worldwide ranked by ideXlab platform
Gerald Schubert - One of the best experts on this subject based on the ideXlab platform.
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a two phase model for compaction and damage 2 applications to compaction deformation and the role of interfacial surface tension
Journal of Geophysical Research, 2001Co-Authors: Yanick Ricard, David Bercovici, Gerald SchubertAbstract:New equations for the dynamics of a two-phase mixture are derived in a companion paper [Bercovici et al., this issue (a)]. These equations do not invoke a bulk viscosity as most previous papers have done, and use the existence of the pressure difference between the two phases, including the possibility of surface energy at the interface between the phases. In this paper we show how a two-phase mixture reacts to simple stress fields. As a basic example, we discuss the deformation of a Porous material confined by an impermeable jacket and loaded by a Porous piston and show that the fluid can never be totally extracted from the matrix. We demonstrate that an unconfined Porous Sample is stronger under shear deformation than under normal stress. We consider spherically symmetric compaction and show that some unphysical results obtained using a constant matrix bulk viscosity are naturally avoided in our approach. We discuss the problem of compaction of a two-phase liquid in the presence of surface tension. In a one-dimensional simulation the surface tension generates porosity instabilities that tend to localize the fluid into narrow sills and dikes that cannot reach the surface.
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A two-phase model for compaction and damage 2. Applications to compaction, deformation, and the role of interfacial surface tension
Journal of Geophysical Research : Solid Earth, 2001Co-Authors: Yanick Ricard, David Bercovici, Gerald SchubertAbstract:New equations for the dynamics of a two-phase mixture are derived in a companion paper [Bercovici et al., this issue (a)]. These equations do not invoke a bulk viscosity as most previous papers have done, and use the existence of the pressure difference between the two phases, including the possibility of surface energy at the interface between the phases. In this paper we show how a two-phase mixture reacts to simple stress fields. As a basic example, we discuss the deformation of a Porous material confined by an impermeable jacket and loaded by a Porous piston and show that the fluid can never be totally extracted from the matrix. We demonstrate that an unconfined Porous Sample is stronger under shear deformation than under normal stress. We consider spherically symmetric compaction and show that some unphysical results obtained using a constant matrix bulk viscosity are naturally avoided in our approach. We discuss the problem of compaction of a two-phase liquid in the presence of surface tension. In a one-dimensional simulation the surface tension generates porosity instabilities that tend to localize the fluid into narrow sills and dikes that cannot reach the surface. Copyright 2001 by the American Geophysical Union.
Yanick Ricard - One of the best experts on this subject based on the ideXlab platform.
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a two phase model for compaction and damage 2 applications to compaction deformation and the role of interfacial surface tension
Journal of Geophysical Research, 2001Co-Authors: Yanick Ricard, David Bercovici, Gerald SchubertAbstract:New equations for the dynamics of a two-phase mixture are derived in a companion paper [Bercovici et al., this issue (a)]. These equations do not invoke a bulk viscosity as most previous papers have done, and use the existence of the pressure difference between the two phases, including the possibility of surface energy at the interface between the phases. In this paper we show how a two-phase mixture reacts to simple stress fields. As a basic example, we discuss the deformation of a Porous material confined by an impermeable jacket and loaded by a Porous piston and show that the fluid can never be totally extracted from the matrix. We demonstrate that an unconfined Porous Sample is stronger under shear deformation than under normal stress. We consider spherically symmetric compaction and show that some unphysical results obtained using a constant matrix bulk viscosity are naturally avoided in our approach. We discuss the problem of compaction of a two-phase liquid in the presence of surface tension. In a one-dimensional simulation the surface tension generates porosity instabilities that tend to localize the fluid into narrow sills and dikes that cannot reach the surface.
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A two-phase model for compaction and damage 2. Applications to compaction, deformation, and the role of interfacial surface tension
Journal of Geophysical Research : Solid Earth, 2001Co-Authors: Yanick Ricard, David Bercovici, Gerald SchubertAbstract:New equations for the dynamics of a two-phase mixture are derived in a companion paper [Bercovici et al., this issue (a)]. These equations do not invoke a bulk viscosity as most previous papers have done, and use the existence of the pressure difference between the two phases, including the possibility of surface energy at the interface between the phases. In this paper we show how a two-phase mixture reacts to simple stress fields. As a basic example, we discuss the deformation of a Porous material confined by an impermeable jacket and loaded by a Porous piston and show that the fluid can never be totally extracted from the matrix. We demonstrate that an unconfined Porous Sample is stronger under shear deformation than under normal stress. We consider spherically symmetric compaction and show that some unphysical results obtained using a constant matrix bulk viscosity are naturally avoided in our approach. We discuss the problem of compaction of a two-phase liquid in the presence of surface tension. In a one-dimensional simulation the surface tension generates porosity instabilities that tend to localize the fluid into narrow sills and dikes that cannot reach the surface. Copyright 2001 by the American Geophysical Union.
Nima Naderi - One of the best experts on this subject based on the ideXlab platform.
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Ultra-sensitive UV sensors based on Porous silicon carbide thin films on silicon substrate
Ceramics International, 2020Co-Authors: Nima Naderi, Mehdi MoghaddamAbstract:Abstract In this report, high-performance ultraviolet (UV) detectors were designed based on Porous silicon carbide (SiC) thin films on silicon (Si) substrate. The results can broaden the applications of Porous SiC structures in sensing applications. Here, n-type Si (100) was used as a substrate for epitaxial growth of SiC thin films. In order to fabricate Porous SiC thin films, a two-electrode, photo-assisted electrochemical etching process was carried out using an integrated current source. The improvement in optical characteristics of Porous SiC/Si was reported by tuning the anodization current density. It was illustrated that current density is an effective parameter for controlling the morphology of Porous Samples. The optical properties of Samples were studied using photoluminescence (PL) and optical reflectometry. The results showed that by applying an optimized value of etching current density, the optical reflectivity is decreased which is due to the elevated specific surface area of Porous Samples that captures the incident light and reduces the reflection. Enhancement in porosity of optimized Porous SiC/Si Sample was illustrated by its elevated PL intensity. The UV sensing capability of fabricated metal-semiconductor-metal (MSM) detectors based on Porous SiC/Si Samples with different etching current densities was investigated. The device based on the optimized Porous Sample showed enhanced sensitivity (54.51) to UV illumination due to the elevated photogenerated current. Moreover, the ultrafast sensing behavior of this device indicates its improved optoelectrical performance in UV detection.
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a combination of electroless and electrochemical etching methods for enhancing the uniformity of Porous silicon substrate for light detection application
Applied Surface Science, 2012Co-Authors: Nima Naderi, M R HashimAbstract:Abstract This paper reports on a combination of electroless and electrochemical etching of a silicon surface for enhancing the uniformity of fabricated Porous silicon substrate and improving the sensitivity of photodetectors. Photo-assisted pulsed electrochemical etching of silicon is modified by introducing a novel parameter called delay time ( T d ), along with cycle time and pause time, of pulsed current, which can affect the morphology of pores. This technique offers the possibility of growing photoluminescent materials with uniform pores and selective wavelength emission. A Sample with a T d of 2 min shows a significant increase in the intensity of the Raman spectrum (10 times stronger than that of the Sample without T d at 518.2 cm −1 ) due to the enhanced surface-assisted multi-phonon processes in Porous film. A red-shift of 2.5 cm −1 and a peak broadening of 1.4 times are also observed for this Porous Sample compared with those of crystalline silicon. Porous surface properties and the performance of the optimized PS as photodetectors are discussed.
M R Hashim - One of the best experts on this subject based on the ideXlab platform.
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a combination of electroless and electrochemical etching methods for enhancing the uniformity of Porous silicon substrate for light detection application
Applied Surface Science, 2012Co-Authors: Nima Naderi, M R HashimAbstract:Abstract This paper reports on a combination of electroless and electrochemical etching of a silicon surface for enhancing the uniformity of fabricated Porous silicon substrate and improving the sensitivity of photodetectors. Photo-assisted pulsed electrochemical etching of silicon is modified by introducing a novel parameter called delay time ( T d ), along with cycle time and pause time, of pulsed current, which can affect the morphology of pores. This technique offers the possibility of growing photoluminescent materials with uniform pores and selective wavelength emission. A Sample with a T d of 2 min shows a significant increase in the intensity of the Raman spectrum (10 times stronger than that of the Sample without T d at 518.2 cm −1 ) due to the enhanced surface-assisted multi-phonon processes in Porous film. A red-shift of 2.5 cm −1 and a peak broadening of 1.4 times are also observed for this Porous Sample compared with those of crystalline silicon. Porous surface properties and the performance of the optimized PS as photodetectors are discussed.
David Bercovici - One of the best experts on this subject based on the ideXlab platform.
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a two phase model for compaction and damage 2 applications to compaction deformation and the role of interfacial surface tension
Journal of Geophysical Research, 2001Co-Authors: Yanick Ricard, David Bercovici, Gerald SchubertAbstract:New equations for the dynamics of a two-phase mixture are derived in a companion paper [Bercovici et al., this issue (a)]. These equations do not invoke a bulk viscosity as most previous papers have done, and use the existence of the pressure difference between the two phases, including the possibility of surface energy at the interface between the phases. In this paper we show how a two-phase mixture reacts to simple stress fields. As a basic example, we discuss the deformation of a Porous material confined by an impermeable jacket and loaded by a Porous piston and show that the fluid can never be totally extracted from the matrix. We demonstrate that an unconfined Porous Sample is stronger under shear deformation than under normal stress. We consider spherically symmetric compaction and show that some unphysical results obtained using a constant matrix bulk viscosity are naturally avoided in our approach. We discuss the problem of compaction of a two-phase liquid in the presence of surface tension. In a one-dimensional simulation the surface tension generates porosity instabilities that tend to localize the fluid into narrow sills and dikes that cannot reach the surface.
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A two-phase model for compaction and damage 2. Applications to compaction, deformation, and the role of interfacial surface tension
Journal of Geophysical Research : Solid Earth, 2001Co-Authors: Yanick Ricard, David Bercovici, Gerald SchubertAbstract:New equations for the dynamics of a two-phase mixture are derived in a companion paper [Bercovici et al., this issue (a)]. These equations do not invoke a bulk viscosity as most previous papers have done, and use the existence of the pressure difference between the two phases, including the possibility of surface energy at the interface between the phases. In this paper we show how a two-phase mixture reacts to simple stress fields. As a basic example, we discuss the deformation of a Porous material confined by an impermeable jacket and loaded by a Porous piston and show that the fluid can never be totally extracted from the matrix. We demonstrate that an unconfined Porous Sample is stronger under shear deformation than under normal stress. We consider spherically symmetric compaction and show that some unphysical results obtained using a constant matrix bulk viscosity are naturally avoided in our approach. We discuss the problem of compaction of a two-phase liquid in the presence of surface tension. In a one-dimensional simulation the surface tension generates porosity instabilities that tend to localize the fluid into narrow sills and dikes that cannot reach the surface. Copyright 2001 by the American Geophysical Union.