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cutting
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The effect of machining parameters on force signal and tool wear in stone cutting
, Article AIP Conference Proceedings, 24 October 2010 through 27 October 2010, Paris ; Volume 1315 , 2010 , Pages 961-966 ; 0094243X (ISSN) ; 9780735408715 (ISBN) ; Gorjizadeh, A ; Mikaeil, R ; Sharif University of Technology
2010
Abstract
The application of sensor system is becoming more commonplace in improving productivity and reliability. Although measuring force signal have been widely used for monitoring of metal machining process that their application to stone cutting has not been well investigated. In this paper, the effect of machining parameter on force signal and tool wear was investigated. The result indicate that increasing of the depth of cut and spindle speed will increase the force and tool wear while increasing feed rate will increase force and decrease tool wear
Extended haessler heuristic algorithm for cutting stock problem: a case study in film industry
, Article Australian Journal of Basic and Applied Sciences ; Volume 3, Issue 4 , 2009 , Pages 3944-3953 ; 19918178 (ISSN) ; Mohammadi, A ; Sharif University of Technology
2009
Abstract
The cutting stock problem is an important problem in the field of combinational optimization. In classic versions of this problem, the aim is to find a solution for cutting some equal-width mother rolls into smaller parts with given width so that the amount of trim-loss become as small as possible. There are plenty of works which addressed the classic cutting stock problem. However in real world applications there are usually some constraints which make the problem different form classical version and make it harder to solve. In this paper we investigate a special cutting stock problem in film industry and show that it can not be solved by using previous methods. We propose a new hybrid...
A Gentzen-style axiomatization for basic predicate calculus
, Article Archive for Mathematical Logic ; Volume 42, Issue 3 , 2003 , Pages 245-259 ; 09335846 (ISSN) ; Ardeshir, M ; Sharif University of Technology
2003
Abstract
We introduce a Gentzen-style sequent calculus axiomatization for Basic Predicate Calculus. Our new axiomatization is an improvement of the previous axiomatizations, in the sense that it has the subformula property. In this system the cut rule is eliminated
Gentzen-style axiomatizations for some conservative extensions of basic propositional logic
, Article Studia Logica ; Volume 68, Issue 2 , 2001 , Pages 263-285 ; 00393215 (ISSN) ; Ardeshir, M ; Sharif University of Technology
Springer Netherlands
2001
Abstract
We introduce two Gentzen-style sequent calculus axiomatizations for conservative extensions of basic propositional logic. Our first axiomatization is an ipmrovement of [1], in the sense that it has a kind of the subformula property and is a slight modification of [6]. In this system the cut rule is eliminated. The second axiomatization is a classical conservative extension of basic propositional logic. Using these axiomatizations, we prove interpolation theorems for basic propositional logic. © 2001 Kluwer Academic Publishers
Simulation of Chip Segmentation in Metal Cutting Using ALE Finite Element Method
, M.Sc. Thesis Sharif University of Technology ; Movahhedy, Mohammad Reza (Supervisor)
Abstract
Since it is important to obtain the suitable cutting conditions for machining and investigate the effect of various parameters on this process, the simulation of this process has been developed extensively by using the finite element method in recent years. Due to very large plastic deformation and also continuous chip flow, one of the most appropriate techniques in modeling chip formation is the arbitrary Lagrangian-Eulerian (ALE) finite element method which has been used in several papers using some traditional codes like ABAQUS or personal codes in recent years. However, one of the limitations in this method is the use of a continuous mesh retains with no change in connectivities which is...
Expand the shares together: envy-free mechanisms with a small number of cuts
, Article Algorithmica ; Volume 81, Issue 4 , 2019 , Pages 1728-1755 ; 01784617 (ISSN) ; Farhadi, M ; Ghodsi, M ; Alijani, R ; Tajik, A. S ; Sharif University of Technology
Springer New York LLC
2019
Abstract
We study the problem of fair division of a heterogeneous resource among strategic players. Given a divisible heterogeneous cake, we wish to divide the cake among n players to meet these conditions: (I) every player (weakly) prefers his allocated cake to any other player’s share (such notion is known as envy-freeness), (II) the allocation is dominant strategy-proof (truthful) (III) the number of cuts made on the cake is small. We provide methods for dividing the cake under different assumptions on the valuation functions of the players. First, we suppose that the valuation function of every player is a single interval with a special property, namely ordering property. For this case, we...
Conditions for regularity and for 2-connectivity of Toeplitz graphs
, Article Utilitas Mathematica ; Volume 110 , 2019 , Pages 305-314 ; 03153681 (ISSN) ; Ghorban, S. H ; Malik, S ; Qajar, S ; Sharif University of Technology
Utilitas Mathematica Publishing Inc
2019
Abstract
Let 1 < ti < t2 < ••• < th < n. A Toeplitz graph G = (V,E) denoted by Tn(tiy ..., f) is a graph where V = {1,. .. ,n} and E = {(m) I i-JI. • • >}}•this paper, we classify all regular Toeplitz graphs. Here, we present some conditions under which a Toeplitz graph has no cut-edge and cut-vertex
Solubility calculation of oil-contaminated drill cuttings in supercritical carbon dioxide using statistical associating fluid theory (PC-SAFT)
, Article Chemical Engineering and Technology ; Volume 31, Issue 1 , 2008 , Pages 66-70 ; 09307516 (ISSN) ; Goodarznia, I ; Daneshi, R ; Sharif University of Technology
2008
Abstract
Supercritical fluid extraction is a new technology that could be effectively used to treat oil-contaminated drill cuttings generated during drilling for oil and gas. In this work, the solubility of oil-contaminated drill cuttings in supercritical carbon dioxide is obtained by an experimental flow type apparatus. The solubility was measured at 200 bar pressure, over a temperature range of 55-79.5°C. The measured solubility and experimental data for oil in drill cuttings were correlated using the PC-SAFT, PR and SRK EOS models, without any adjustable parameters. Average absolute derivations of less than 15.1 %, 98.7 %, and 99.3 % are achieved between predicted and experimental values for the...
Investigation of optimum condition in oxygen gas-assisted laser cutting
, Article Optics and Laser Technology ; Volume 41, Issue 4 , 2009 , Pages 454-460 ; 00303992 (ISSN) ; Bahar, M ; Sharif University of Technology
2009
Abstract
Laser cutting characteristics including power level and cutting gas pressure are investigated in order to obtain an optimum kerf width. The kerf width is investigated for a laser power range of 50-170 W and a gas pressure of 1-6 bar for steel and mild steel materials. Variation of sample thickness, material type, gas pressure and laser power on the average cut width and slot quality are investigated. Optimum conditions for the steel and mild steel materials with a thickness range of 1-2 mm are obtained. The optimum condition for the steel cutting results in a minimum average kerf width of 0.2 mm at a laser power of 67 W, cutting rate of 7.1 mm/s and an oxygen pressure of 4 bar. A similar...
Beyond the cut-set bound: Uncertainty computations in network coding with correlated sources
, Article IEEE Transactions on Information Theory ; Volume 59, Issue 9 , 2013 , Pages 5708-5722 ; 00189448 (ISSN) ; Yang, S ; Jaggi, S ; Sharif University of Technology
2013
Abstract
Cut-set bounds are not, in general, tight for all classes of network communication problems. In this paper, we introduce a new technique for proving converses for the problem of transmission of correlated sources in networks, which results in bounds that are tighter than the corresponding cut-set bounds. We also define the concept of 'uncertainty region' which might be of independent interest. We provide a full characterization of this region for the case of two correlated random variables. The bounding technique works as follows: on one hand, we show that if the communication problem is solvable, the uncertainty of certain random variables in the network with respect to imaginary parties...
A Supervisory Fuzzy Force Control of CNC HEXAGLIDE Robot
,
M.Sc. Thesis
Sharif University of Technology
;
Alasti, Aria
(Supervisor)
;
Vossoughi, Gholamreza
(Supervisor)
Abstract
In this paper, controlling the cutting force of an end-milling process using a supervisory fuzzy controller has been investigated. The proposed control consists of an ordinary fuzzy controller and a fuzzy supervisor. In a machining process, there are several parameters which do not contribute to the force control system directly. Therefore an ordinary fuzzy force controller is suitable when these parameter have only small amount of variations. Since in practice this assumption is not valid, then a supervisory fuzzy controller has been added to the system. The designed fuzzy supervisor, inspects the dynamic behavior of the cutting force, estimates a pre-defined ‘sensitivity’ parameter and...
An ACO algorithm for one-dimensional cutting stock problem [electronic resource]
, Article Journal of Industrial engineering International ; September 2005, Vol. 1, No. 1, pp. 10-19 ; Javanshir, H ; Sharif University of Technology
Abstract
The one-dimensional cutting stock problem, has so many applications in lots of industrial processes and during the past few years has attracted so many researchers’ attention all over the world. In this paper a metaheuristic method based on ACO is presented to solve this problem. In this algorithm, based on designed probabilistic laws, artificial ants do select various cuts and then select the best patterns. Also because of the problem framework, effective improvements has been made to problem solving process. The results of that algorithm in sample problems, show high efficiency of the algorithm in different levels of problems
Anaerobic treatment by UASB reactor and aerobic biodegradability test of cutting oil sewage
, Article Journal of Environmental Studies ; Vol. 40, issue. 1 , 2014 , p. 211-220 ; Sajadi, A. A ; Mirzaei, M ; Hoseynian, H ; Sharif University of Technology
Abstract
Introduction: Water is consumed in almost all industries. Consequently the used water is turning to a waste that usually should be treated to meet the regulated standard level prior to reuse or discharge into the environment. Cutting oil wastewater is an emulsion normally comprised ofl-10% oil and the remainder water. The main functions of this oil in industry are lubrication, friction reduction, and cooling of instrument s parts. This wastewater is classified as a toxic waste according to the existence of some additive material to prevent corrosion and bacterial growth. Breakage of the emulsion and separation of the water and the oil can alone reduce more than about 90% of the aqueous phase...
Design of a gas lift system to increase oil production from an Iranian offshore well with high water cut
, Article Australian Journal of Basic and Applied Sciences ; Volume 5, Issue 11 , 2011 , Pages 1561-1565 ; 19918178 (ISSN) ; Morshedi, S ; Sedaghat, M. H ; Aghahoseini, S ; Sharif University of Technology
Abstract
One of the most important production issues in oil fields is high water production which may lead to wells killing and reduction in an economical production period. With the increment of water production or decrease of reservoir pressure, reservoir drawdown pressure reduces which causes reduction in oil production rate. To preserve the reservoir production, we should apply one of the proposed methods; namely, increasing the reservoir pressure, preventing water source invasion or using artificial lift technique. To compensate this reduction, continuous gas injection into the wells can be used. The injected gas combines with fluid in tubing and the density of the fluid decreases, thereby...
Genetic algorithm for solving fuzzy shortest path problem in a network with mixed fuzzy arc lengths
, Article AIP Conference Proceedings, 2 December 2010 through 4 December 2010, Sarawak ; Volume 1337 , 2011 , Pages 265-270 ; 0094243X (ISSN) ; 9780735408937 (ISBN) ; Tajdin, A ; Hassanzadeh, R ; Mahdavi-Amiri, N ; Shafieian, H ; Sharif University of Technology
2011
Abstract
We are concerned with the design of a model and an algorithm for computing a shortest path in a network having various types of fuzzy arc lengths. First, we develop a new technique for the addition of various fuzzy numbers in a path using α -cuts by proposing a linear least squares model to obtain membership functions for the considered additions. Then, using a recently proposed distance function for comparison of fuzzy numbers. we propose a new approach to solve the fuzzy APSPP using of genetic algorithm. Examples are worked out to illustrate the applicability of the proposed model
A shortest path algorithm for a network with various fuzzy arc lengths
, Article AIP Conference Proceedings, 2 February 2010 through 4 February 2010, Gold Coast, QLD ; Volume 1239 , 2010 , Pages 260-267 ; 0094243X (ISSN) ; 9780735407855 (ISBN) ; Mahdavi, I ; Mahdavi Amiri, N ; Sadeghpour Gildeh, B ; Hadighi, R ; Sharif University of Technology
2010
Abstract
We are concerned with the design of a model and an algorithm for computing a shortest path in a network having various types of fuzzy arc lengths. First, we develop a new technique for the addition of various fuzzy numbers in a path using α-cuts. Then, we propose a regression model for obtaining membership function for the considered addition. Finally, we present a dynamic programming method for finding a shortest path in the network. An example is worked out to illustrate the applicability of the proposed approach
Optimum experimental condition in oxygen gas-assisted low power Nd:Yag laser cutting
, Article Modern Physics Letters B ; Volume 23, Issue 6 , 2009 , Pages 877-890 ; 02179849 (ISSN) ; Golnabi, H ; Sharif University of Technology
2009
Abstract
The optimum condition for the reactive gas-assisted Nd:YAG laser cuttings is described in this article. The cut kerf width is investigated for a laser power range of 50-170 W and a gas pressure of 1-6 bar for steel and mild steel materials. Variation of sample thickness, material type, gas pressure and the laser power on the cut width and slot quality are considered in this study. An overall 338 experiments at different experimental conditions are performed and the kerf results are compared. Optimum conditions for the steel and mild steel materials with a thickness range of 1-2 mm are obtained. The optimum condition for the steel cutting results in a minimum kerf width of 0.2 mm at a laser...
Effects of tool rake angle and tool nose radius on surface quality of ultraprecision diamond-turned porous silicon
, Article Journal of Manufacturing Processes ; Volume 37 , 2019 , Pages 321-331 ; 15266125 (ISSN) ; Akbari, J ; Yan, J ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
This paper presents an investigation of the effects of tool rake angle and nose radius on the surface quality of ultraprecision diamond-turned porous silicon. The results showed that as rake angle decreases, the high-stress field induced by the tool edge increases, causing microcracks to propagate extensively near the pore walls. As a result, the ductile-machined areas shrank under a negative tool rake angle. On the other hand, brittle fracture occurred around pores released cutting pressure significantly. These trends of rake angle effects are distinctly different from those in the cutting of non-porous silicon. Finite element simulation of stress in the cutting area agreed with the...
Numerical analysis of metal cutting with chamfered and blunt tools
, Article Journal of Manufacturing Science and Engineering ; Volume 124, Issue 2 , 2002 , Pages 178-188 ; 10871357 (ISSN) ; Altintas, Y ; Gadala, M. S ; Sharif University of Technology
American Society of Mechanical Engineers(ASME)
2002
Abstract
In high speed machining of hard materials, tools with chamfered edge and materials resistant to diffusion wear are commonly used. In this paper, the influence of cutting edge geometry on the chip removal process is studied through numerical simulation of cutting with sharp, chamfered or blunt edges and with carbide and CBN tools. The analysis is based on the use of ALE finite element method for continuous chip formation process. Simulations include cutting with tools of different chamfer angles and cutting speeds. The study shows that a region of trapped material zone is formed under the chamfer and acts as the effective cutting edge of the tool, in accordance with experimental observations....
Biological upgrading of heavy oil cuts using native microbial consortia as an environmental-friendly technology in petroleum refineries
, Article Advances in Environmental Technology ; Volume 8, Issue 3 , 2022 , Pages 215-228 ; 24766674 (ISSN) ; Ziaei Rad, Z ; Shayegan, J ; Pazouki, M ; Hossinia, A ; Sharif University of Technology
Iranian Research Organization for Science and Technology
2022
Abstract
Refineries are amongst the most energy-intensive and polluting industries in the world. Biotechnology may serve as an alternative low-cost and environmental-friendly tool to the current costly, toxic and hazardous refining processes. In this study, the compositional redistribution of a heavy hydrocarbon cut is investigated under biological conversion using native microbial consortia. The native consortia were obtained by batch enrichment method applied on oil-polluted soil samples from oil refineries of Iran. The bioconversion experiments were conducted with 20% and 40% (v/v) of the heavy cut as the sole carbon source and 10% (v/v) of the consortia broth in 250 ml flasks containing a mineral...