arXiv subjects

Ali Shafiei

Publications and source records attributed to Ali Shafiei.

8 recordsLinked to original sources

arXiv2024

Emo3D: Metric and Benchmarking Dataset for 3D Facial Expression Generation from Emotion Description

Existing 3D facial emotion modeling have been constrained by limited emotion classes and insufficient datasets. This paper introduces "Emo3D", an extensive "Text-Image-Expression dataset" spanning a wide spectrum of human emotions, each paired with images and 3D blendshapes. Leveraging Large Language Models (LLMs), we generate a diverse array of textual descriptions, facilitating the capture of a broad spectrum of emotional expressions. Using this unique dataset, we conduct a comprehensive evaluation of language-based models' fine-tuning and vision-language models like Contranstive Language Image Pretraining (CLIP) for 3D facial expression synthesis. We also introduce a new evaluation metric for this task to more directly measure the conveyed emotion. Our new evaluation metric, Emo3D, demonstrates its superiority over Mean Squared Error (MSE) metrics in assessing visual-text alignment and semantic richness in 3D facial expressions associated with human emotions. "Emo3D" has great applications in animation design, virtual reality, and emotional human-computer interaction.

cs.CV↗

arXiv2021

Design of Eutectic High Entropy Alloys

Eutectic high entropy alloys (EHEAs) are emerging as an exciting new class of structural alloys as they have shown very promising mechanical properties. However, how to design these alloys has been a challenge. In this work, a simple approach is presented for designing EHEAs. The introduced approach uses the composition of binary and ternary eutectic alloys for finding the composition of EHEAs. The approach is based on the assumption that EHEAs are originated from binary and ternary eutectic alloys. The approach is applied for alloy systems Al-Co-Cr-Fe-Ni, Co-Cr-Fe-Ni, Co-Cr-Fe-Ni-Ti, and Co-Cr-Fe-Ni-Ta and several EHEAs are predicted for these alloy systems. The predicted results are verified with thermodynamic simulations and experimental data. The results show that the introduced approach can be considered as a feasible and easy-to-use method for designing EHEAs. Based on the developed approach, any binary eutectic alloy can be used for designing multicomponent eutectic alloys.

cond-mat.mtrl-sci↗

arXiv2021

A Molecular Dynamics Study on CO$_2$ Diffusion Coefficient in Saline Water Under a Wide Range of Temperatures, Pressures, and Salinity Concentrations: Implications to CO2 Geological Storage

Carbon dioxide (CO$_2$) sequestration in saline aquifers has been introduced as one of the most practical, long-term, and safe solutions to tackle a growing threat originating from the emission of CO$_2$. Successfully executing and planning the process necessitates a comprehensive understanding of CO$_2$ transport properties -- particularly the diffusion coefficient, influencing the behavior of CO$_2$ dissolution in water/brine regarding the shape of viscous fingers, the onset of instabilities, etc. In this research, Molecular Dynamics (MD) simulation was employed to compute the CO$_2$ diffusion coefficient in various NaCl saline water concentrations under the broad spectrum of temperatures and pressures to acquire a data-set. The NaCl concentration increase gives rise to a decrease in the CO$_2$ diffusion coefficient, by which the reduction is most notably at higher temperatures. In addition, the rise in the CO$_2$ diffusion at elevated temperatures can be explained by the cation's hydration shell size reduction with temperature increment due to intensifying repulsive forces among water molecules. A new precise correlation is proposed for estimating CO$_2$ diffusion coefficients. Regarding the pressure variation effects, no tangible changes are observed with pressure increase. Furthermore, the variability of the CO$_2$ diffusion coefficient in the presence of other salts, namely MgCl2, CaCl2, KCl, and Na2SO4, were computed separately. Comparing the influence of various salts, CaCl2 and KCl have the highest and lowest effect on the CO$_2$ diffusion coefficient, respectively. Finally, a set of direct numerical simulations was conducted to study the impact of the CO$_2$ diffusion coefficient on the CO$_2$ dissolution process. The results shed light on the importance of CO$_2$ diffusion coefficient changes under the saline water condition in predicting dissolution process behavior and further calculations.

cond-mat.mes-hall↗

arXiv2020

New approach to model the yield strength of body centered cubic solid solution refractory high entropy alloys

A simple fitting approach is used for modeling the compressive yield strength of body centered cubic (bcc) solid solution high entropy alloys in Al-Hf-Nb-Mo-Ta-Ti-V-Zr system. It is proposed that the yield strength could be modeled by a polynomial where the experimental data can be used for finding the polynomial coefficients. The results show that the proposed polynomial could model the yield strength of solid solution alloys relatively well. The developed polynomial is used for predicting the strength of RHEAs in Hf-Mo-Nb-Ta-Ti-V-Zr system. It is observed that the yield strength of alloys within this system increases with the additions of Mo and Zr and decreases with the addition of Ti. Furthermore, the model predicts that the yield strength increases with increasing the value of parameters valence electron concentration (VEC) and atomic size difference (ASD). Although the developed polynomial does not consider the mechanisms involved in the strengthening of alloys, it can be considered as a straightforward method for assessing the strength of solid solution RHEAs.

cond-mat.mtrl-sci↗

arXiv2020

The design of eutectic high entropy alloys in Al-Co-Cr-Fe-Ni system

In the present work, a simple approach is proposed for predicting the compositions of eutectic high entropy alloys (EHEAs) in Al-Co-Cr-Fe-Ni system. It is proposed that eutectic lines exist between certain eutectic alloys in this system and, as a result, new eutectic or near-eutectic compositions can be obtained by mixing the alloys which are located on the same eutectic line. The approach is applied for a series of experimentally verified eutectic alloys and new eutectic or near-eutectic alloys are designed for Al-Co-Cr-Fe-Ni system. Furthermore, by investigating the compositions of verified eutectic alloys in Al-Co-Cr-Fe-Ni system, compositional diagrams are proposed which show the relations between the concentrations of constituent elements in eutectic alloys. The compositional diagrams suggest that EHEAs are derived from binary and ternary eutectic alloys. Moreover, the proposed diagrams can be considered as convenient methods for evaluating the composition of EHEAs in Al-Co-Cr-Fe-Ni system.

cond-mat.mtrl-sci↗

arXiv2020

A dual-phase cobalt alloy with a triple yielding phenomenon under compression test

The compressive mechanical behavior of a dual phase cobalt alloy (Al$_{14}$Co$_{41}$Cr$_{16}$Fe$_{11}$Ni$_{18}$) is reported in this communication. An uncommon triple yielding phenomenon is observed in the as-cast condition. Microstructural studies suggest that the observed behavior may be due to a stress/strain-induced martensitic phase transformation.

cond-mat.mtrl-sci↗

arXiv2019

Continuous-variable entanglement distillation by cascaded photon replacement

We study the entanglement distillation in continuous variable systems when a photon replacement protocol is employed. A cascaded protocol is studied and we find that the resultant entanglement increases by increasing the number of repetitions. Interestingly, the entanglement enhancement is not sensitive to the asymmetry of the protocol and gives the same result for any arrangement in the absence of loss. The non-Gaussianity of the outcome state is also studied and it is found that the non-Gaussianity of the state dramatically depends on the experimental arrangements. By providing practical information on photon replacement operation, this work is one step towards realization of universal quantum computation. In particular, in setups where deGaussifying protocols are only applicable to one of the parties.

quant-ph↗

arXiv2019

Fluid-structure coupling of concentric double FGM shells with different lengths

The aim of this study is to develop a semi-analytical method to investigate fluid-structure coupling of concentric double shells with different lengths and elastic behaviours. Co-axial shells constitute a cylindrical circular container and a baffle submerged inside the stored fluid. The container shell is made of functionally graded materials with mechanical properties changing through its thickness continuously. The baffle made of steel is fixed along its top edge and submerged inside fluid such that its lower edge freely moves. The developed approach is verified using a commercial finite element computer code. Although the model is presented for a specific case in the present work, it can be generalized to investigate coupling of shellplate structures via fluid. It is shown that the coupling between concentric shells occurs only when they vibrate in a same circumferential mode number, n. It is also revealed that the normalized vibration amplitude of the inner shell is about the same as that of the outer shell, for narrower radial gaps. Moreover, the natural frequencies of the fluid-coupled system gradually decrease and converge to the certain values as the gradient index increases.

cond-mat.mtrl-sci↗