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The densification behavior of metals and alloys during spark plasma sintering: A mini-review
, Article Science of Sintering ; Volume 51, Issue 2 , 2019 , Pages 1-18 ; 0350820X (ISSN) ; Esmaeeli Seraji, M ; Sharif University of Technology
International Institute for the Science of Sintering (IISS)
2019
Abstract
As of today, metals and alloys are widely utilized as structural, mechanical, electrical, and magnetic materials in every aspect of technology and industry. The complexity and diversity of metals applications emphasize the need for a new production method to quickly and easily manufacture metallic components. Spark plasma sintering as a new solid-state sintering method has been recently developed to respond to these needs. Up to now, numerous papers and researches have been published in the field of spark plasma sintering and its ability to manufacture metallic samples. Density is a significant property that has a great influence on the physical, mechanical, and functional properties of...
Co-precipitation Synthesis Parameters of Lithium-rich Cathode Material
, M.Sc. Thesis Sharif University of Technology ; Sadrnezhaad, Khatiboleslam (Supervisor)
Abstract
Electric vehicles and electronics such as laptops and smartphones require an efficient amount of energy conversion and storage. As one of the reliable systems in this field, lithium-ion batteries have high energy density and lower emissions. Cathodic material is a bottleneck in the development of lithium-ion systems due to its high cost and limited energy capacity. In this study, lithium-rich oxide cathode was synthesized in the liquid phase using the co-precipitation synthesis method using six-aqueous nickel nitrate and four-aqueous manganese chloride precursors. The material was analyzed by structural characterization analysis as well as electrochemical characterizations. In this project,...
Geodesic spanners for points in R3 amid axis-parallel boxes
, Article Information Processing Letters ; Volume 166 , 2021 ; 00200190 (ISSN) ; Rezaei Seraji, M. J ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Let P be a set of n points in R3 amid a bounded number of obstacles. Consider the metric space M=(P,dM) where dM(p,q) is the geodesic distance of p and q, i.e., the length of a shortest path from p to q avoiding obstacles. When obstacles are axis-parallel boxes, we prove that M admits an 83-spanner with O(nlog3n) edges. In other words, let S be a complete graph on n vertices where each node corresponds to a point p∈P. For nodes u and v of S corresponding to p,q∈P, the edge (u,v) is associated with the geodesic distance of p and q as its weight. We indeed prove that S admits a near linear-size t-spanner for some constant t. © 2020 Elsevier B.V
Geodesic spanners for points in R3 amid axis-parallel boxes
, Article Information Processing Letters ; Volume 166 , 2021 ; 00200190 (ISSN) ; Rezaei Seraji, M. J ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Let P be a set of n points in R3 amid a bounded number of obstacles. Consider the metric space M=(P,dM) where dM(p,q) is the geodesic distance of p and q, i.e., the length of a shortest path from p to q avoiding obstacles. When obstacles are axis-parallel boxes, we prove that M admits an 83-spanner with O(nlog3n) edges. In other words, let S be a complete graph on n vertices where each node corresponds to a point p∈P. For nodes u and v of S corresponding to p,q∈P, the edge (u,v) is associated with the geodesic distance of p and q as its weight. We indeed prove that S admits a near linear-size t-spanner for some constant t. © 2020 Elsevier B.V
Scattering Correction in PET Device using Deep Learning
, M.Sc. Thesis Sharif University of Technology ; Vosoghi, Naser (Supervisor) ; Ghaffarian, Pardis (Co-Supervisor) ; Sheikhzadeh, Peyman (Co-Supervisor)
Abstract
Positron Emission Tomography (PET) imaging is a modern sectional imaging technique widely used due to its advantages in visualizing the physiological functions of body tissues. In this method, a radiotracer is injected into the body, concentrating in the area of interest. As the positron-emitting radionuclide decays, positron annihilation occurs, resulting in the emission of two gamma rays in opposite directions. The PET scanner detects these gamma rays; however, scattering may occur during their journey from the patient’s body to the detector, which can introduce errors in tumor localization. To reconstruct images and correct for these scatter effects, various techniques such as iterative...
Adaptive Lossless Image Compression of Pipelines in Smart Structures
, M.Sc. Thesis Sharif University of Technology ; Mortazavi, Mohammad (Supervisor) ; Ghorshi, Mohammad Ali (Supervisor)
Abstract
Structural Health Monitoring (SHM) means to give a diagnosis of the “state” of the subjects. Small leaks along the entire lengths of oil pipelines are detected and located by monitoring.Nowadays health monitoring of pipeline in water, gas, oil and chemical industry has been the focus of researchers. This is due to the fact that leak accidents may cause great economic problems to human resources as well as extreme environmental pollution. This project focuses on a visual and photographic observation system as leakage detection to monitor long range pipelines. In this system, several cameras with overlapping views are located along the entire lengths of pipelines. We are using digital cameras...
Online Conflict-free Coloring Of Intervals
, M.Sc. Thesis Sharif University of Technology ; Abam, Mohammad Ali (Supervisor)
Abstract
In this thesis, we consider the problem of online conflict-free coloring for regions. First, we analyze online variant of the conflict-free coloring of intervals on the line, where each newly inserted interval must be assigned a color upon insertion such that the coloring remains conflict-free, i.e. for every point p in the union of the current intervals, there must be an interval I with a unique color among all intervals covering p. we present deterministic algorithm for achieving this goal which uses O(log^3n) color. Next, we consider the online conflict-free coloring of nearly-equal axis-parallel rectangles in the plane and present a deterministic algorithms which uses O(log^12n)...
Geodesic spanners for points on a polyhedral terrain
, Article SIAM Journal on Computing ; Volume 48, Issue 6 , 2019 , Pages 1796-1810 ; 00975397 (ISSN) ; De Berg, M ; Rezaei Seraji, M. J ; Sharif University of Technology
Society for Industrial and Applied Mathematics Publications
2019
Abstract
Let S be a set of n points on a polyhedral terrain T in ℝ3, and let ϵ > 0 be a fixed constant. We prove that S admits a (2 + ϵ )-spanner with O(n log n) edges with respect to the geodesic distance. This is the first spanner with constant spanning ratio and a near-linear number of edges for points on a terrain. On our way to this result, we prove that any set of n weighted points in Rd admits an additively weighted (2 + ϵ )-spanner with O(n) edges; this improves the previously best known bound on the spanning ratio (which was 5 + ϵ ) and almost matches the lower bound. © 2019 Society for Industrial and Applied Mathematics Publications. All rights reserved
Geodesic spanners for points on a polyhedral terrain
, Article SIAM Journal on Computing ; Volume 48, Issue 6 , 2019 , Pages 1796-1810 ; 00975397 (ISSN) ; De Berg, M ; Rezaei Seraji, M. J ; Sharif University of Technology
Society for Industrial and Applied Mathematics Publications
2019
Abstract
Let S be a set of n points on a polyhedral terrain T in ℝ3, and let ϵ > 0 be a fixed constant. We prove that S admits a (2 + ϵ )-spanner with O(n log n) edges with respect to the geodesic distance. This is the first spanner with constant spanning ratio and a near-linear number of edges for points on a terrain. On our way to this result, we prove that any set of n weighted points in Rd admits an additively weighted (2 + ϵ )-spanner with O(n) edges; this improves the previously best known bound on the spanning ratio (which was 5 + ϵ ) and almost matches the lower bound. © 2019 Society for Industrial and Applied Mathematics Publications. All rights reserved
Geodesic spanners for points on a polyhedral terrain
, Article 28th Annual ACM-SIAM Symposium on Discrete Algorithms, SODA 2017, 16 January 2017 through 19 January 2017 ; 2017 , Pages 2434-2442 ; 9781611974782 (ISBN) ; De Berg, M ; Rezaei Seraji, M. J ; Universitat Politecnica de Catalunya ; Sharif University of Technology
Association for Computing Machinery
2017
Abstract
Let S be a set S of n points on a polyhedral terrain T in R3, and let ϵ > 0 be a fixed constant. We prove that S admits a (2 + ϵ)-spanner with O(n log n) edges with respect to the geodesic distance. This is the first spanner with constant spanning ratio and a near-linear number of edges for points on a terrain. On our way to this result, we prove that any set of n weighted points in Rd admits an additively weighted (2 + ϵ)-spanner with O(n) edges; this improves the previously best known bound on the spanning ratio (which was 5 + ϵ), and almost matches the lower bound. Copyright © by SIAM
The role of heat treatment on wear behavior of powder metallurgy low alloy steels
, Article Materials and Design ; Volume 23, Issue 7 , 2002 , Pages 667-670 ; 02641275 (ISSN) ; Habibi, S. M ; Yoozbashizadea, H ; Janghorban, K ; Reihani, S. M. S ; Rahmani Seraji, H ; Ashtari, M ; Sharif University of Technology
Elsevier Ltd
2002
Abstract
The influence of manufacturing parameters such as compacting pressure, heat treatment and microstructure on the static and dynamic properties of Fe-1.75 Ni-1.5 Cu-0.5 Mo-0.6 C was investigated. Wear and fatigue tests were carried out on reciprocate wearing and tension compression mode, respectively. The results show that delamination wear mechanism of sintered steel is similar to that of conventional wrought or cast materials. But, in sintered material, open porosity acts as sites of generation and collection of wear debris or formation of subsurface cracks. Wear rate is decreased and fatigue strength is increased by heat treatment. © 2002 Elsevier Science Ltd. All rights reserved
An analytical review on Spark Plasma Sintering of metals and alloys: from processing window, phase transformation, and property perspective
, Article Critical Reviews in Solid State and Materials Sciences ; 2022 ; 10408436 (ISSN) ; Sovizi, S ; Azarniya, A ; Giuntini, D ; Seraji, M. E ; Hosseini, H. R. M ; Amutha, C ; Ramakrishna, S ; Mukasyan, A ; Sharif University of Technology
Taylor and Francis Ltd
2022
Abstract
ABSTRACTs: The need for fully dense material with well-engineered microstructures has led to the promising emergence of innovative sintering technologies among which the Spark Plasma Sintering (SPS) is one of the most favorite. Unlike the conventional sintering processes, SPS takes advantage of a current flow passing through the sintering die and metallic powders by which fast densification with minimal grain growth and enhanced physicomechanical properties can be obtained. Albeit there is a growing interest in the exploitation of SPS in producing sufficiently consolidated metallic parts, no analytical review has been released over the effects of SPS parameters on the densification behavior,...
Physicomechanical Properties of Porous Materials by Spark Plasma Sintering
, Article Critical Reviews in Solid State and Materials Sciences ; Volume 45, Issue 1 , 2020 , Pages 22-65 ; Azarniya, A ; Safavi, M. S ; Farshbaf Ahmadipour, M ; Esmaeeli Seraji, M ; Sovizi, S ; Saqaei, M ; Yamanoglu, R ; Soltaninejad, M ; Madaah Hosseini, H. R ; Ramakrishna, S ; Kawasaki, A ; Adams, S ; Reddy, M. V ; Sharif University of Technology
Taylor and Francis Inc
2020
Abstract
Metallic or ceramic micro/nanoporous materials have attracted particular attention due to some interesting structural and functional properties. There exist a variety of methods for producing porous materials by which optimized features can be reached. Spark plasma sintering (SPS) is one of these new-emerging approaches. This technique is often combined with conventional technologies and produce a variety of porous structures with tailorable microstructure and physicomechanical properties. This review addresses SPS and obtainable porous materials with nanoscale and microscale microstructural features. The processing methods, microstructural phenomena, and physicomechanical properties of...