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ardeshir-larijani--morteza
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Experimental Study of Movement of Mercury Droplets in Micro Channel by Electromagnetic Force
, M.Sc. Thesis Sharif University of Technology ; Afshin, Hossein (Supervisor)
Abstract
As today's tremendous advance occurred in biotechnology and nanotechnology, the microfluidic devices made a new success that was not possible with the traditional equipments. It was useful in such a way that by using a microliter volume of that fluid, we could have the ability to use it in biologics, medicine, aerospace, cooling electronic systems and medical discovery. One of the main component of fluidic microsystems are micropumps in which they divide into two types. Reciprocating micropumps have been worked by stimulating electromagnetic micropumps which is based on Lorentz law. In this project, we try to investigate the impact of effective parameters in the movement of the mercury mass....
Design and Optimization of Helium Extraction and Liquefaction Cycle from Natural Gas by Direct Method
, Ph.D. Dissertation Sharif University of Technology ; Afshin, Hossein (Supervisor)
Abstract
Helium is known as a strategic material due to its unique properties and applications in the development of advanced industries. Currently, natural gas is the only source from which helium can be produced economically. The United States, Qatar, Algeria, and Russia have the largest share of helium production, respectively. In this research, the process of helium extraction from natural gas and its liquefaction, independent of LNG production based on helium in South Pars gas of Iran, which is the largest helium reservoir in the world, were designed and simulated.In the helium liquefaction section, the speed and accuracy of the process simulation were improved by developing a home code based on...
Simulation and performance improvement of cryogenic distillation column, using enhanced predictive Peng–Robinson equation of state
, Article Fluid Phase Equilibria ; Volume 489 , 2019 , Pages 117-130 ; 03783812 (ISSN) ; Bayat, M ; Afshin, H ; Sharif University of Technology
Elsevier B.V
2019
Abstract
In this study, a cryogenic distillation column has been designed and simulated via a computer code based on the theta method of convergence. The required thermodynamic properties are determined from the enhanced predictive Peng-Robinson (E-PPR 78) equation of state which has a good accuracy in predicting the corresponding thermodynamic properties of natural gas components. The combined code of distillation column/equation of state has been verified with that of another study. In the present study, the results are achieved by the constant molar over-flow and inclusion of energy equations assumptions. In order to have more accuracy in the results, the energy equations were considered in the...
Simulation of hybrid reo connectors
, Article 3rd CSI/CPSSI International Symposium on Real-Time and Embedded Systems and Technologies, RTEST 2020, 10 June 2020 through 11 June 2020 ; 2020 ; Farhadi, A ; Arbab, F ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
The prevalence of complex Cyber-Physical Systems (CPS) as an increasingly ubiquitous technology, necessitates the incorporation of component based and compositional design methods for the development and deployment of such systems. In this paper, we introduce a hybrid coordination framework to specify CPSs with components and use the resulting models to simulate, validate and verify those systems, using UPPAAL statistical model checker (SMC). We use SMC because with a level of uncertainty and unpredictability (e.g., the physical environment with which a CPS interacts), simulation-based verification approaches, where properties are guaranteed with a degree of confidence, produce more...
Parallel hermite interpolation on the pyramid
, Article 22nd International Symposium on Computer and Information Sciences, ISCIS 2007, Ankara, 7 November 2007 through 9 November 2007 ; February , 2007 , Pages 403-407 ; 1424413648 (ISBN); 9781424413645 (ISBN) ; Sarbazi Azad, H ; Sharif University of Technology
2007
Abstract
The pyramid network is one of the most important interconnection topologies used as hardware architecture or software data structure. It has a combined tree-mesh structure making it suitable for solving many parallel problems and applications. This paper proposes a parallel algorithm for Hermite Interpolation on the Pyramid network which has at least N nodes. The proposed algorithm has 3 phases: initialization, main, and final. The algorithm is optimal with a time complexity of O(N) for an N-point interpolation. ©2007 IEEE
Design and implementation of an ADC-based real-time simulator along with an optimal selection of the switch model parameters
, Article Electrical Engineering ; Volume 103, Issue 5 , 2021 , Pages 2315-2325 ; 09487921 (ISSN) ; Zolghadri, M. R ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2021
Abstract
The method for modeling switching converters plays a key role in real-time simulators. Associate discrete circuit (ADC) modeling technique is a commonly used method for modeling the switching converter. However, the optimal selection of the ADC-based switch model parameters has great importance in the accuracy of the real-time simulator. In this paper, the design of a real-time simulator for a switching power converter has been done, in which a novel method for detecting optimum values of the switch model parameters has been expressed. Particle swarm optimization (PSO) algorithm is used to find these optimum values using state-space analysis of the modeled circuit in the z-domain. The...
Investigation of effective parameters on the performance of the helium liquefaction cycle
, Article International Journal of Heat and Technology ; Volume 37, Issue 4 , 2019 , Pages 1009-1018 ; 03928764 (ISSN) ; Eslami, M ; Afshin, H ; Sharif University of Technology
International Information and Engineering Technology Association
2019
Abstract
Due to its unique properties, helium has wide application in different industries and scientific fields, which has turned it into a strategic material. Helium liquefaction plants include wide temperature range from 300 k to 4.2 k, so these plants have high energy consumption. A lot of studies have done to optimize the operation of these cycles. In this research, an exergy analysis is performed for a liquid helium production plant. The optimal performance of 3 and 4 stage cycles is extracted using parametric study and the results are compared with those of Collins dual-expander cycle. The results show that by increasing the number of cooling stages, not only the compressor optimum discharge...
Investigation of effective parameters on the performance of the helium liquefaction cycle
, Article International Journal of Heat and Technology ; Volume 37, Issue 4 , 2019 , Pages 1009-1018 ; 03928764 (ISSN) ; Eslami, M ; Afshin, H ; Sharif University of Technology
International Information and Engineering Technology Association
2019
Abstract
Due to its unique properties, helium has wide application in different industries and scientific fields, which has turned it into a strategic material. Helium liquefaction plants include wide temperature range from 300 k to 4.2 k, so these plants have high energy consumption. A lot of studies have done to optimize the operation of these cycles. In this research, an exergy analysis is performed for a liquid helium production plant. The optimal performance of 3 and 4 stage cycles is extracted using parametric study and the results are compared with those of Collins dual-expander cycle. The results show that by increasing the number of cooling stages, not only the compressor optimum discharge...
A unification of the basic logics of Sambin and Visser
, Article Logic Journal of the IGPL ; Volume 20, Issue 6 , 2012 , Pages 1202-1213 ; 13670751 (ISSN) ; Vaezian, V ; Sharif University of Technology
2012
Abstract
In logical literature, the phrase 'basic logic' refers to at least three different logical systems. The first one, basic propositional logic, BPL was introduced by Albert Visser in 1981. This logic is a subintuitionistic logic that can be obtained from intuitionistic logic by weakening of modus ponens. The second logical system with the name 'basic logic', is the system B that was introduced by G. Sambin and G. Battilotti in 1997. The goal of this logical system is to provide a common foundation for all usual non-modal logics. The third one is called 'basic logic' by P. Hajek in the field of Fuzzy Logic. We show that the two systems BPL and B do not have a direct relationship (i.e. none of...
On the constructive notion of closure maps
, Article Mathematical Logic Quarterly ; Volume 58, Issue 4-5 , 2012 , Pages 348-355 ; 09425616 (ISSN) ; Ramezanian, R ; Sharif University of Technology
Wiley
2012
Abstract
Let A be a subset of the constructive real line. What are the necessary and sufficient conditions for the set A such that A is continuously separated from other reals, i.e., there exists a continuous function f with f -1(0) = A? In this paper, we study the notions of closed sets and closure maps in constructive reverse mathematics
The double negation of the intermediate value theorem
, Article Annals of Pure and Applied Logic ; Volume 161, Issue 6 , 2010 , Pages 737-744 ; 01680072 (ISSN) ; Ramezanian, R ; Sharif University of Technology
2010
Abstract
In the context of intuitionistic analysis, we consider the set F consisting of all continuous functions φ{symbol} from [0, 1] to R such that φ{symbol} (0) = 0 and φ{symbol} (1) = 1, and the set I0 consisting of φ{symbol}'s in F where there exists x ∈ [0, 1] such that φ{symbol} (x) = frac(1, 2). It is well-known that there are weak counterexamples to the intermediate value theorem, and with Brouwer's continuity principle we have I0 ≠ F. However, there exists no satisfying answer to I0¬ ¬ =? F. We try to answer to this question by reducing it to a schema (which we call ED) about intuitionistic decidability that asserts "there exists an intuitionistically enumerable set that is not...
Decidability and Specker sequences in intuitionistic mathematics
, Article Mathematical Logic Quarterly ; Volume 55, Issue 6 , 2009 , Pages 637-648 ; 09425616 (ISSN) ; Ramezanian, R ; Sharif University of Technology
2009
Abstract
A bounded monotone sequence of reals without a limit is called a Specker sequence. In Russian constructive analysis, Church's Thesis permits the existence of a Specker sequence. In intuitionistic mathematics, Brouwer's Continuity Principle implies it is false that every bounded monotone sequence of real numbers has a limit. We claim that the existence of Specker sequences crucially depends on the properties of intuitionistic decidable sets. We propose a schema (which we call ED) about intuitionistic decidability that asserts "there exists an intuitionistic enumerable set that is not intuitionistic decidable" and show that the existence of a Specker sequence is equivalent to ED. We show that...
Latarres, lattices with an arrow
, Article Studia Logica ; 2017 , Pages 1-32 ; 00393215 (ISSN) ; Ruitenburg, W ; Sharif University of Technology
2017
Abstract
A latarre is a lattice with an arrow. its axiomatization looks natural. Latarres have a nontrivial theory which permits many constructions of latarres. Latarres appear as an end result of a series of generalizations of better known structures. These include Boolean algebras and Heyting algebras. Latarres need not have a distributive lattice. © 2017 Springer Science+Business Media B.V
Compactness, colocatedness, measurability and ED
, Article Logic Journal of the IGPL ; Volume 26, Issue 2 , January , 2018 , Pages 244-254 ; 13670751 (ISSN) ; Ghafouri, Z ; Sharif University of Technology
Oxford University Press
2018
Abstract
In classical analysis, every compact subset of ℝ is Lebesgue measurable, but it is not true in constructive analysis. In this paper, we prove that the statement 'every compact set K in a locally compact space X is integrable with respect to a positive measure μ' is equivalent to LPO, over Bishop's constructive analysis. We also prove that the existence of a compact subset of ℝ which is not Lebesgue integrable is equivalent to the schema ED, which asserts that 'there exists an intuitionistically enumerable subset of ℕ which is not intuitionistically decidable'. Moreover, classically, every open subset of ℝ is Lebesgue measurable, but it is not true constructively. We show that Lebesgue...
The principle of open induction and specker sequences
, Article Logic Journal of the IGPL ; Volume 25, Issue 2 , 2017 , Pages 232-238 ; 13670751 (ISSN) ; Ghafouri, Z ; Sharif University of Technology
Oxford University Press
2017
Abstract
The schema ED asserts that 'there exists an intuitionistically enumerable subset of N which is not intuitionistically decidable.' In this article, we prove that in the presence of Markov's Principle over Bishop's constructive analysis, ¬ED is equivalent to the principle of open induction on [0,1], via Specker sequences. © 2016. Oxford University Press. All rights reserved
The Σ1-provability logic of HA
, Article Annals of Pure and Applied Logic ; Volume 169, Issue 10 , 2018 , Pages 997-1043 ; 01680072 (ISSN) ; Mojtahedi, M ; Sharif University of Technology
Elsevier B.V
2018
Abstract
In this paper we introduce a modal theory iHσ which is sound and complete for arithmetical Σ1-interpretations in HA, in other words, we will show that iHσ is the Σ1-provability logic of HA. Moreover we will show that iHσ is decidable. As a by-product of these results, we show that HA+□⊥ has de Jongh property. © 2018 Elsevier B.V
The Σ1-Provability Logic of HA
, Article Journal of Symbolic Logic ; Volume 84, Issue 3 , 2019 , Pages 1118-1135 ; 00224812 (ISSN) ; Mojtahedi, M ; Sharif University of Technology
Cambridge University Press
2019
Abstract
For the Heyting Arithmetic HA,HA is defined [14, 15] as the theory {A | HA-A}, where is called the box translation of A (Definition 2.4). We characterize the Σ1-provability logic of HA as a modal theory (Definition 3.17). © 2019 The Association for Symbolic Logic
Latarres, Lattices with an Arrow
, Article Studia Logica ; Volume 106, Issue 4 , 2018 , Pages 757-788 ; 00393215 (ISSN) ; Ruitenburg, W ; Sharif University of Technology
Springer Netherlands
2018
Abstract
A latarre is a lattice with an arrow. Its axiomatization looks natural. Latarres have a nontrivial theory which permits many constructions of latarres. Latarres appear as an end result of a series of generalizations of better known structures. These include Boolean algebras and Heyting algebras. Latarres need not have a distributive lattice. © 2017, Springer Science+Business Media B.V
An introduction to basic arithmetic
, Article Logic Journal of the IGPL ; Volume 16, Issue 1 , 2008 , Pages 1-13 ; 13670751 (ISSN) ; Hesaam, B ; Sharif University of Technology
Oxford University Press
2008
Abstract
We study Basic Arithmetic BA, which is the basic logic BQC equivalent of Heyting Arithmetic HA over intuitionistic logic IQC, and of Peano Arithmetic PA over classical logic CQC. It turns out that The Friedman translation is applicable to BA. Using this translation, we prove that BA is closed under a restricted form of the Markov rule. Moreover, it is proved that all nodes of a finite Kripke model of BA are classical models of Ι∃1+, a fragment of PA with Induction restricted to the formulas made up of ∃, ∧ and/or ∨. We also study an interesting extension of BQC, called EBQC, which is the extension by the axiom schema ⊤ → →. We show that this extension behaves very like to IQC, and the...
On some questions of L. Åqvist
, Article Logic Journal of the IGPL ; Volume 14, Issue 1 , 2006 , Pages 1-13 ; 13670751 (ISSN) ; Nabavi, F ; Sharif University of Technology
Oxford University Press
2006
Abstract
We give answers to some questions raised by L. Åqvist in [6] and [7]. The question raised in [7] which we will answer positively is about the representability of Åqvist's system G in a hierarchy of alethic modal logics Hm, m = 1, 2, .... On the other hand, the questions raised in [6] are about the completeness of some monadic alethic denotic logics with respect to their Kripke semantics. © Copyright 2006 Oxford University Press