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A novel method for prediction of parameters of naturally fractured condensate reservoirs using pressure response analysis
, Article Journal of Natural Gas Science and Engineering ; Vol. 19, issue , July , 2014 , p. 13-22 ; ISSN: 18755100 ; Jamshidi, S ; Masihi, M ; Sharif University of Technology
2014
Abstract
Producing from gas condensate reservoirs under dew-point pressure and at constant temperature shows a complex behavior because of existing liquid condensate around the well. Zones with different mobilities generate three zones as a zone away from the well containing only gas, a zone having liquid around the well and finally a zone containing movable oil and gas. Existence of condensate around wellbore reduces gas relative permeability and as a result productivity index of the well will decrease. In fact, this condensate acts like an additional skin and investigating of this behavior can be difficult because of the complex fluid flow processes. Well test analysis in naturally fractured...
Pressure Response Analysis of Naturally Fractured Condensate Reservoirs Regarding the Effect of Permeability Anisotropy
, M.Sc. Thesis Sharif University of Technology ; Jamshidi, Saied (Supervisor) ; Masihi, Mohsen (Co-Advisor)
Abstract
Producing from Gas Condensate Reservoirs under dew point pressure and at constant temperature may have a complex behavior because of existing two phase system and liquid around the well. Zones with different mobility generate as a zone away from the well containing only gas, a zone having liquid around the well and finally a zone with capillary effect. Existence of condensate around well reduces gas relative permeability and as a result productivity index of well decreases. In fact these condensate acts like an additional skin and because of some complex processes, investigating of these behaviors can be difficult.
Well testing analysis in Natural Fractured reservoir is generally based...
Well testing analysis in Natural Fractured reservoir is generally based...
Synthesis of zero-valent iron nanoparticles via electrical wire explosion for efficient removal of heavy metals
, Article Clean - Soil, Air, Water ; Volume 45, Issue 3 , 2017 ; 18630650 (ISSN) ; Rabiee, H ; Seyed Shahabadi, S. M ; Borghei, S. M ; Sharif University of Technology
2017
Abstract
In this paper, electrical wire explosion (EWE) was used as a simple, clean, in situ method to synthesise nano zero-valent iron (nZVI) particles in liquid mediums. The structural and physical properties of the synthesised nZVI particles were characterised by x-ray diffraction, Brunauer–Emmett–Teller analysis, field emission scanning electron microscopy and transmission electron microscopy. The synthesised spherical nanoparticles, at a specific size of 10–50 nm, possessed large surface areas of approximately 13.27 m2/g, reinforcing the significant advantages of EWE, that is, less aggregation and in situ production of nanoparticles with enhanced removal efficacy, for groundwater treatment....
Computation of armature reaction field and full-load characteristics of an axial flux surface mounted pm machine using a new analytical approach
, Article 26th Iranian Conference on Electrical Engineering, ICEE 2018, 8 May 2018 through 10 May 2018 ; 2018 , Pages 1027-1031 ; 9781538649169 (ISBN) ; Sharifi, A. H ; Abedini Mohammadi, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
In recent years axial flux permanent magnet (AFPM) machines have found industrial applications because of such characteristics as high power density, compact structure and disc-like shape. Like other electrical machines, prediction of flux density distribution in the air gap of AFPM is essential. In this paper, an analytical method for calculation of air gap flux density caused by armature reaction is presented. The solution is based on Maxwell's equations. Separation of variables method is applied to field equations and 2D distribution of magnetic flux density in the air gap calculated in term of Fourier series. The 2-D distribution of three-phase armature winding is modeled exactly....
Preparation and characterization of PVC/PAN blend ultrafiltration membranes: Effect of PAN concentration and PEG with different molecular weight
, Article Desalination and Water Treatment ; Volume 58 , 2017 , Pages 1-11 ; 19443994 (ISSN) ; Mojtaba Seyedi, S ; Rabiei, H ; Alvandifar, N ; Arya, A ; Sharif University of Technology
Desalination Publications
2017
Abstract
The current study investigates the effect of polyacrylonitrile (PAN) addition on morphology and antifouling properties of poly(vinyl chloride) (PVC) asymmetric flat ultrafiltration (UF) membranes. The membranes are prepared via phase inversion method induced by immersion precipitation at different PVC/PAN blending ratio up to 40 wt% PAN. Also, membranes with blending ratio of PVC/ PAN:70/30, which showed the highest water flux and flux recovery ratio, were used for membrane preparation with 4 wt% of Polyethylene glycol (PEG) addition in four different molecular weight, 600 Da, 1,000 Da, 6,000 Da and 20,000 Da, which was used as pore former and hydrophilic polymeric additive. The performance...
Superhydrophobic dual layer functionalized titanium dioxide/polyvinylidene fluoride-co-hexafluoropropylene (TiO2/PH) nanofibrous membrane for high flux membrane distillation
, Article Journal of Membrane Science ; Volume 537 , 2017 , Pages 140-150 ; 03767388 (ISSN) ; Rabiee, H ; Seyedi, S. M ; Mokhtare, A ; Brant, J. A ; Sharif University of Technology
Elsevier B.V
2017
Abstract
In this study, superhydrophobic dual layer membranes with highly porous structure were fabricated using electrospinning and electrospraying techniques. Electrospinning method was used to produce the support nanofibrous layer using polyvinylidene fluoride-co-hexafluoropropylene (PH) as the polymer and a mixed solvent system of N,N-Dimetylformamide (DMF) and acetone. Afterwards, hydrophobic, functionalized TiO2 nanoparticles were deposited on the surface of the support layer using the electrospraying technique. TiO2 chemical functionalization and their deposition on the support layer were investigated by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy. The...
One-for-one period policy in a two-echelon inventory system with commoncycle and poisson demand rate for retailers
, Article 2009 International Conference on Computers and Industrial Engineering, CIE 2009 ; 2009 , Pages 831-834 ; 9781424441365 (ISBN) ; Tayebi, H ; Haji, B ; Sharif University of Technology
2009
Abstract
This paper deals with a two-echelon inventory system consisting of onesupplier and N retailers. Each retailer faces an independent Poisson demand withthe same rate and applies a new ordering policy called one-for-one- periodordering policy for its inventory control. In this ordering policy the ordersize is equal to one and the time interval between any two consecutive ordersforms a common fixed cycle. Thus, the supplier faces a deterministic demand andadopts a deterministic inventory policy. At each cycle he orders a batch of sizeN to his own supplier. Upon receipt of each batch he sends 1 unit of theproduct to each retailer with a transportation cost. In this paper, for theabove system we...
Developing a partial backlogging deteriorating inventory model with selling price dependant demand rate and cycle length dependant selling price
, Article 2008 IEEE International Conference on Industrial Engineering and Engineering Management, IEEM 2008, Singapore, 8 December 2008 through 11 December 2008 ; January , 2008 , Pages 198-202 ; 9781424426300 (ISBN) ; Sabahno, H ; Haji, R ; Sharif University of Technology
2008
Abstract
In this paper, we develop an inventory model with price dependant demand rate, under time value of money and inflation, finite time horizon, exponential backlogging rate and exponential deterioration rate with the objective of maximizing the present worth of the total system profit. Using a dynamic programming based solution algorithm, we are able to find the optimal sequence of the cycles and also to obtain different optimal selling prices and optimal order quantities for the cycles with unequal lengths, which have never been done before for our model. We also use a proper numerical example to show accuracy of the solution procedure. © 2008 IEEE
The effect of HRT and carriers on the sludge specifications in MBR to remove VOCs from petrochemical wastewater
, Article Desalination and Water Treatment ; Volume 57, Issue 46 , 2016 , Pages 21730-21742 ; 19443994 (ISSN) ; Shayegan, J ; Mojtaba Seyedi, S ; Sharif University of Technology
Taylor and Francis Inc
2016
Abstract
This work employs two membrane bioreactors (with and without carrier) to evaluate the influence of carrier and hydraulic retention time (HRT) on the sludge specifications when removing organic volatile compounds (e.g. styrene and ethylbenzene) from petrochemical wastewater. This study is conducted during three various HRTs. The results indicate that the optimum HRT (e.g. 15 h.) was achieved in the reactor with carrier during biological removal and membrane fouling minimization. During the optimum HRT, the biological removal efficiency for styrene, ethylbenzene, and COD is 99.8 ± 0.1%, 99.8 ± 0.1%, and 99 ± 0.8%, respectively, and the concentration of styrene and ethylbenzene in the exit air...
Biodegradation kinetics and interactions of styrene and ethylbenzene as single and dual substrates for a mixed bacterial culture
, Article Journal of Environmental Health Science and Engineering ; 2015 ; 2052336X (ISSN) ; Shayegan, J ; Seyedi, S. M ; Sharif University of Technology
BioMed Central Ltd
2015
Abstract
This study examined biodegradation kinetics of styrene and ethylbenzene as representatives of alkenylbenzenes and mono-alkylbenzenes, respectively. The compounds were studied independently and as binary mixtures using a series of aerobic batch degradation experiments introduced by acclimatized mix culture. Initial concentration of styrene and ethylbenzene in the liquid phase vacillated from 0 to 220 mg/l. The Andrew model was applied for the biodegradation of individual substrates and the estimated constants of the equation for styrene and ethylbenzene were μmax = 0.1581, 0.2090 (1/h), KS =25.91, 37.77 (mg/L), KI =13.15, 62.62 (mg/L), respectively. The accomplished parameters from single...
The effect of HRT and carriers on the sludge specifications in MBR to remove VOCs from petrochemical wastewater
, Article Desalination and Water Treatment ; Dec , 2015 , Pages 1-13 ; 19443994 (ISSN) ; Shayegan, J ; Mojtaba Seyedi, S ; Sharif University of Technology
Taylor and Francis Inc
2015
Abstract
This work employs two membrane bioreactors (with and without carrier) to evaluate the influence of carrier and hydraulic retention time (HRT) on the sludge specifications when removing organic volatile compounds (e.g. styrene and ethylbenzene) from petrochemical wastewater. This study is conducted during three various HRTs. The results indicate that the optimum HRT (e.g. 15 h.) was achieved in the reactor with carrier during biological removal and membrane fouling minimization. During the optimum HRT, the biological removal efficiency for styrene, ethylbenzene, and COD is 99.8 ± 0.1%, 99.8 ± 0.1%, and 99 ± 0.8%, respectively, and the concentration of styrene and ethylbenzene in the exit air...
Minimizing expected discounted cost in a queueing loss model with discriminating arrivals
, Article European Journal of Operational Research ; Volume 282, Issue 2 , 2020 , Pages 593-601 ; Ross, S ; Sharif University of Technology
Elsevier B.V
2020
Abstract
We consider a queuing loss system with heterogeneous skill based servers and Poisson arrivals. We first assume that each arrival has a vector (X1,…,Xn) of independent binary random variables with Xi=1 if server i is eligible to serve that arrival. The service time at server i is exponential with rate μi. Arrivals finding no servers that are both idle and eligible to serve them are lost. Assuming the system incurs a cost of one unit for each lost customer, our goal is to find the optimal policy for assigning arrivals to idle and eligible servers so as to minimize the expected discounted cost of the system. Later, we generalize our model by considering k server pools where each pool i is...
A trace-time framework for prediction of elevation angle over land mobile LEO satellites networks
, Article Wireless Personal Communications ; Volume 62, Issue 4 , February , 2012 , Pages 793-804 ; 09296212 (ISSN) ; Rahimi, F ; Sharif University of Technology
2012
Abstract
Elevation angle is one of the most significant parameters of land mobile satellite channels, subject to rapid variations in the case of Low Earth Orbit (LEO) satellite systems. In this paper a novel trace-based framework is proposed and analyzed which is capable of predicting elevation angle as a function of time during satellite visibility window. Trace-time based modeling makes the framework practical for real-time evaluation of elevation angle and its alteration incurred by communication links in LEO satellite systems. The proposed method is particularly suitable for development of communication channel models and services in mobile LEO satellite networks where path variability is of...
Erratum: A trace-time framework for prediction of elevation angle over land mobile LEO satellites networks (Wireless Personal Communications DOI 10.1007/s11277-010-0094-5)
, Article Wireless Personal Communications ; Volume 62, Issue 4 , February , 2012 , Pages 805-806 ; 09296212 (ISSN) ; Rahimi, F ; Sharif University of Technology
2012
Identification And Assessment of Major Risks Associated with Heavy Equipment Transportation in Iranian Oil, Gas and Petrochemical Projects
, M.Sc. Thesis Sharif University of Technology ; Eslami, Hossein (Supervisor)
Abstract
Transportation of heavy and super heavy equipment is one of the issues that have been discussed in recent years. High cost and required expertise of Transportation for oil and gas projects has caused many organizations and Iranian companies turn to outsourcing strategy and have invested a lot of money in this field without regard to its Risks. Unfortunately, the lack of risk management in transportation projects has led to an increase in refractive index. In this thesis, have been identified the risks of heavy and super-heavy transport equipment in the oil, gas and petrochemical industries then prioritize the risks identified. Finally, each of the identified risks in Iran is investigated....
Explanation of Policy Process for the Legislative Bill to Establish Free Trade, Industrial and Special Economic Zones in 2018 in Iran
, M.Sc. Thesis Sharif University of Technology ; Maleki, Ali (Supervisor)
Abstract
Understanding and interpreting the process that policy goes through from the agenda-setting stage to the implementation and evaluation stages have many difficulties and complexities. One way to facilitate the understanding of this process is to use theories that explain the policy process. The purpose of this research is to explain the process that has passed through the legislative bill of eight free trade zones and one hundred and three special economic zones in Iran in 2018. To reach this goal using two theories of Multiple Streams Analysis (MSA) and the Advocacy Coalition Framework (ACF).Due to the nature and aims of this research, the qualitative approach and case study method have been...
Probability estimation in aircraft conflict detection: A simple and computationally effective method with accuracy certificates
, Article 18th European Control Conference, ECC 2019, 25 June 2019 through 28 June 2019 ; 2019 , Pages 4319-4324 ; 9783907144008 (ISBN) ; Nobahari, H ; Prandini, M ; European Control Assoication (EUCA) ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
In this paper, we address aircraft conflict detection on a mid-term horizon. We adopt a probabilistic approach and provide a simple method to estimate the probability of two aircraft getting closer than some minimum predefined distance, based on a commonly adopted Gaussian model of the deviation from their planned trajectories. A key feature of our method is that the probability estimate is accompanied by a deterministic accuracy certificate. This is achieved by adopting a geometric approach to conflict probability estimation and jointly computing a lower and an upper bound on the conflict probability. These bounds can be inspected and refined if the resulting accuracy of the probability...
The Rate of Fields’ Variations Toward the Distance of Two Horizons in Dilatonic Black Holes and its Relation With Time, Near the Extremality
, M.Sc. Thesis Sharif University of Technology ; Arfaei, Hessamaddin (Supervisor)
Abstract
Among the various types of black holes, dilatonic black holes can be mentioned which are in the center point of view at their extremality. In this study, we pay attention to these answers and their fields and the way they behave variously, especially when the coupling constant α is between 0and1. For doing so, in chapter one we attempt to study one of the simplest answers in General Relativity (Schwarzschild) and some beginning contexts. Then in chapter two, we try another answer (Reissner Nordstrom) which contains non-Extremal and Extremal states. In chapter three we introduce the concept of the higher theories. Chapter four is a hint about hawking radiation. And finally in chapter five, we...
Developing two deteriorating inventory models with selling price dependant demand rate and cycle time dependant selling price
, Article 37th International Conference on Computers and Industrial Engineering 2007, Alexandria, 20 October 2007 through 23 October 2007 ; Volume 2 , 2007 , Pages 1330-1339 ; 9781627486811 (ISBN) ; Haji, R ; Sabahno, H ; Sharif University of Technology
2007
Abstract
In this paper we develop two models; the without shortages and the completely backlogging shortages with the price dependant demand rate under time value of money and inflation, finite time horizon and exponentially deterioration rate with the objective of maximizing the present worth of the total system profit. Using the dynamic programming method for each model, we are able to obtain different selling price, order quantity and cycle length for each cycle. We also use a proper numerical example to show accuracy of the solution procedures and to compare the results. This research and its results are unique and have never been concluded before
The M/M/1 queue with inventory, lost sale, and general lead times
, Article Queueing Systems ; Volume 75, Issue 1 , January , 2013 , Pages 65-77 ; 02570130 (ISSN) ; Asmussen, S ; Haji, R ; Sharif University of Technology
2013
Abstract
We consider an M/M/1 queueing system with inventory under the (r,Q) policy and with lost sales, in which demands occur according to a Poisson process and service times are exponentially distributed. All arriving customers during stockout are lost. We derive the stationary distributions of the joint queue length (number of customers in the system) and on-hand inventory when lead times are random variables and can take various distributions. The derived stationary distributions are used to formulate long-run average performance measures and cost functions in some numerical examples