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Continuous-wave amplification in bismuth-oxide fiber optical parametric amplifiers
, Article 2011 IEEE Winter Topicals, WTM 2011, 10 January 2011 through 12 January 2011, Keystone, CO ; 2011 , Pages 161-162 ; 9781424484287 (ISBN) ; Jamshidifar, M ; Govan, D ; Marhic, M. E ; Sharif University of Technology
Abstract
We review our investigations on bismuth-oxide fiber as an amplifying medium for parametric amplifiers with continuous-wave pumping. The results lead to new applications in demultiplexing, which are discussed
Effect of higher-order waves in parametric oscillatory instability in optical cavities
, Article Physica Scripta ; Volume 83, Issue 4 , 2011 ; 00318949 (ISSN) ; Bahrampour, A. R ; Sharif University of Technology
Abstract
A new strict proposal for determining radiation pressure coupling to optical resonator devices has been developed. Our evidence shows that the effect of the anti-Stokes wave cannot be neglected. It is shown that Stokes and anti-Stokes frequencies of all orders will participate in the optomechanical effect. Furthermore, we have shown that for the input pump power, there exists a threshold value for instability behavior. Radiation pressure can couple mechanical modes of a cavity to its optical modes, leading to parametric oscillation instability. Here we present an approximate analysis of such a nonlinear effect with Hamilton's least action principle. Loss in every mode has been taken into...
Effects of corrugated roughness on gaseous slip flow forced convection in microtubes
, Article Journal of Thermophysics and Heat Transfer ; Volume 25, Issue 2 , 2011 , Pages 262-271 ; 08878722 (ISSN) ; Salarieh, H ; Saidi, M. H ; Mozafari, A. A ; Sharif University of Technology
Abstract
Because of technological restrictions, it is actually impossible to fabricate smooth microchannels. Therefore, exploring the roughness effects on the flow characteristics at microscale is of great importance for scientific communities. The present investigation deals with the effects of corrugated roughness on the fully developed slip flow forced convection in micropipes. The governing equations subject to first-order slip boundary conditions are solved by means of the straightforward perturbation method. Closed-form expressions are obtained for the dimensionless velocity and temperature distributions, for the friction coefficient and pressure drop, and finally for the Nusselt number. The...
Spatial resolution enhancement in fiber Raman distributed temperature sensor by employing ForWaRD deconvolution algorithm
, Article Optical Fiber Technology ; Volume 17, Issue 2 , 2011 , Pages 128-134 ; 10685200 (ISSN) ; Moosavi, A ; Bahrampour, M. J ; Safaei, L ; Sharif University of Technology
Abstract
Governing equations of a Raman fiber distributed temperature sensor supported by a counter propagating pumped Raman amplifier are written in the form of integral equations. Forward pump and backward going probe are in the pulsed and continuous wave modes of operation respectively. It is shown that powers of the forward and backward Raman signals (stokes and anti stokes) approximately are the convolution of the input forward pump pulse and corresponding optical fiber impulse responses. The Fourier Wavelet Regularized Deconvolution (ForWaRD) method is employed to improve the spatial resolution in fiber Raman distributed temperature sensor without reducing the pulse width of the laser source
Rotary magnetohydrodynamic micropump based on slug trapping valve
, Article Journal of Microelectromechanical Systems ; Volume 20, Issue 1 , December , 2011 , Pages 260-269 ; 10577157 (ISSN) ; Shafii, M. B ; Sharif University of Technology
2011
Abstract
A novel rotary magnetohydrodynamic (MHD) (RMHD) micropump is presented in this paper in order to both benefit exclusive advantages from the MHD micropumps and eliminate the current obstacles in their implementation. Lorentz force, which is the actuation mechanism in RMHD, is used to propel a mercury slug in a circular microchannel in order to suck the working fluid from the inlet and pump it to the outlet. This idea is integrated with a valve which prevents the working fluid from passing through, while allowing the mercury slug to pass, during each pumping loop. The performance of a fabricated RMHD is evaluated, considering parameters such as pressure difference, running duration, electric...
A novel revolving piston minipump
, Article Sensors and Actuators, B: Chemical ; Volume 218 , October , 2015 , Pages 237-244 ; 09254005 (ISSN) ; Shafii, M. B ; Moosavi, A ; Amiri Hezave, H ; Sharif University of Technology
Elsevier
2015
Abstract
In this study, a novel prototype high-efficiency miniature pump that uses magnetic properties of a ferrofluid in both pumping and valving mechanisms is presented. The minichannel consisting of a cylindrical pumping chamber, a check valve, an inlet and an outlet, comprises six bonded layers of PMMA. A cylindrical permanent magnet that is placed inside the chamber and is externally actuated by a motorized off-center permanent magnet, functions as a revolving piston which sweeps the perimeter of the cylinder. Ferrofluid is used to cover the gaps between the magnetic piston and the channel walls, also serves as a separating plug between the inlet and the outlet of the chamber preventing...
Modeling the Solar Heat Pump with an Energy Storage System
, M.Sc. Thesis Sharif University of Technology ; Samimi , Jalal (Supervisor) ; Vesaghi, Mohammad Ali (Supervisor)
Abstract
Purpose of ongoing thesis is providing a tool for suitable modeling, increase efficiency and decrease construction cost of solar absorption heat pump. At first, the solar absorption heat pump is modeled by the thermodynamic laws. Then, this model is converted to the new standard mathematical programming model using exergy and thermodynamic Analysis with considering all technical and economic constrains. This mathematical model is optimized by Genetic algorithm (GA). Because of the nonlinear objective function and the constraint, GA is used as optimization algorithm. After applying GA, optimized parameters of cycle heat exchanger designing and its electricity consumption are calculated....
Thermal-economic Modeling and Optimization of Ground-Coupled Heat Pump System for Various Climatic Conditions of Iran
, M.Sc. Thesis Sharif University of Technology ; Abbaspour Tehrani Fard, Madjid (Supervisor)
Abstract
The optimal design of a ground-coupled heat pump (GCHP) system with vertical ground heat exchanger (VGHX) includes thermal modeling of the system and selection of optimal design parameters is presented in this research. Then, by applying Nelder-Mead optimization algorithm, an objective function (Total Annual Cost which is the sum of annual investment and operating costs of the system) is defined and minimized, exposed to specified design constraints. Also, Genetic Algorithm is used to verify the optimal design process. In order to evaluate the accuracy of a presented model, the optimum values of a heat pump design parameters includes saturated temperature/pressure of a condenser and...
Investigation of Potential Failure Modes of Electric Submersible Pumps and Propose New Methods for Fault Diagnosis and Condition Monitoring of
Electric Submersible Pump
,
M.Sc. Thesis
Sharif University of Technology
;
Behzad, Mehdi
(Supervisor)
Abstract
Despite of many advantages, electro submersible pumps (ESP) have very high costs in maintenance. Since ESP usually operates in deep wells, it should be transported to the surface in order to malfunction. In addition, the state of ESP equipment cannot be determined because of unavailability of vibration measurement on the site. Thus, this equipment fails suddenly. This process costs a lot on country’s oil and water & wastewater industry. so in this thesis, at first, the potential failure modes (PFM) of ESPs are investigated, then proper methods are presented for condition monitoring. Finally, the presented methods are verified by experimental tests and wavelet analysis. The results show that...
Technical and Economical Feasibility Study of Applying Heat Pump Systems to Provide Utilities for Oil & Gas Industries
, M.Sc. Thesis Sharif University of Technology ; Sattari, Sorena (Supervisor) ; Amidpour, Majid (Supervisor)
Abstract
Distillation is the most applied unit in the separation processess of the oil and gas industries. Because the distillation process requires energy in the form of the utilities, integration of heat pump systems in the distillation process as an application of these systems is considered in this research. A new and effective methodology of proper integrating of heat pump and distillation columns has been proposed by collecting thermodynamic and thermoeconomic tools. Then, this procedure has been applied on the ethane recovery and NGL fractionation units of 4 & 5 phases of the south pars field. The exergy analysis of the distillation columns is the first step of this methodology as the...
Exergy Analysis of Thermoacoustic Heat Pump with Industrial Application
, Ph.D. Dissertation Sharif University of Technology ; Ghorbanian, Kaveh (Supervisor)
Abstract
Typical thermoacoustic systems deal with the conversion of heat energy to sound energy and vice versa. Recent advances in the field of thermoacoustics have altered the working mechanism of many conventional heating and cooling devices. These systems have three highlighted advantages: first, they have simple structure, no moving parts, low cost of manufacture, and high reliability; second, by using inert gases as working fluid, they are environmentally friendly; and finally, heat driven thermoacoustic devices can be driven by low quality energy sources such as waste heat and solar energy.
The main focus of the present thesis is on the application of the thermoacoustic technology in the...
The main focus of the present thesis is on the application of the thermoacoustic technology in the...
Assessment of Water and Sewage Facilities of Kish Island and Offering Solutions in Emergency Conditions (A Case Study on Kish Island)
, M.Sc. Thesis Sharif University of Technology ; Hashemian, Jamal (Supervisor)
Abstract
Vulnerability of water and sewage infrastructure in Kish Island survey versus natural and unnatural threats. It is important to know what to do when crisis or unpredicted event occurs in the Island. Decision makers and master managers of the Island, as the main custodians make suitable and effective reactions and decisions so that the impact of threats is reduced to minimum. According to the threats, there are short term and long term solutions. These solutions can be applied when the Island is encountered with crisis
Diffuser miniature pump with an extra ferrofluidic valve
, Article Microfluidics and Nanofluidics ; Volume 19, Issue 5 , November , 2015 , Pages 1235-1244 ; 16134982 (ISSN) ; Shafii, M. B ; Moosavi, A ; Sharif University of Technology
Springer Verlag
2015
Abstract
This paper presents the prototype design and fabrication of a magnetically actuated miniature pump that utilizes self-sealing capability of ferrofluid-covered permanent magnets in both pumping and valving mechanisms. The valving action is performed by employing one active valve along with two nozzle/diffuser elements. Two cylindrical permanent magnets are placed inside the flat-wall channels: One magnet acts as the active valve and the other one serves as a reciprocating piston actuating the working fluid. In order to seal the gaps between the channel walls and the permanent magnet of the valve/piston, ferrofluid is used to cover the surfaces of both magnets. The valve and the piston are...
Low-cost reciprocating electromagnetic-based micropump for high-flow rate applications
, Article Journal of Micro/ Nanolithography, MEMS, and MOEMS ; Volume 14, Issue 3 , July , 2015 ; 19325150 (ISSN) ; Salari, A ; Shafii, M. B ; Sharif University of Technology
SPIE
2015
Abstract
A reciprocating single-chamber micropump is designed and experimentally tested. The actuation technique of the pump is based on Lorentz force acting on an array of low-weight microwires placed on a flexible membrane surface. A square-wave electric current (5.6 and 7.8 A) with a low-frequency range (5.6 to 7.6 Hz) is applied through the microwires in the presence of a perpendicular magnetic field (0.08 to 0.09 T). The resultant oscillating Lorentz force causes the membrane to oscillate with the same frequency, and pushes the fluid to flow toward the outlet using a high-efficiency ball-valve. The micropump has exhibited a maximum efficiency of 2.03% with a flow rate as high as 490 μl/s and...
Almost zero-jitter optical clock recovery using all-optical kerr shutter switching techniques
, Article Journal of Lightwave Technology ; Volume 33, Issue 9 , February , 2015 , Pages 1737-1747 ; 07338724 (ISSN) ; Salehi, J. A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
In this paper, a new all optical phase-locked loop (OPLL) is proposed and analyzed. The scheme relies on using two optical Kerr shutters to reveal the OPLL's error signal. The set of optical Kerr shutters and the subsequent low-speed photodetectors realize two nonlinear cross-correlations between the local clock pulse stream (called pump in Kerr shutter notations) and the time-shifted replicas of the incoming received data signal (called probe). The outputs of the cross-correlators are subtracted to form the error signal of the OPLL. We characterize the mathematical structure of the proposed OPLL and identify its two intrinsic sources of phase noise, namely, randomness of the received...
On the use of pumped storage for wind energy maximization in transmission-constrained power systems
, Article IEEE Transactions on Power Systems ; Volume 30, Issue 2 , 2015 , Pages 1017-1025 ; 08858950 (ISSN) ; Abbaspour, A ; Fotuhi Firuzabad, M ; Moeini Aghtaie, M ; Sharif University of Technology
Abstract
Owing to wind power inherent characteristics and technical constraints of power systems operation, a considerable amount of wind energy cannot be delivered to load centers and gets curtailed. Transmission congestion together with temporal mismatch between load and available wind power can be accounted as the main reasons for this unpleasant event. This paper aims to concentrate on the wind energy curtailment for which it provides a combinatorial planning model to maximize wind power utilization. Jointly operating the wind power generation system with pumped hydro energy storage (PHES), the planning procedure tries to reach schemes with the minimum level of wind energy curtailment as well as...
Evaluation of methods for estimating aquifer hydraulic parameters
, Article Applied Soft Computing Journal ; Volume 28 , March , 2015 , Pages 541-549 ; 15684946 (ISSN) ; Mortazavi Naeini, M ; Ataie Ashtiani, B ; Jeng, D. S ; Khanbilvardi, R ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
An accurate estimation of aquifer hydraulic parameters is required for groundwater modeling and proper management of vital groundwater resources. In situ measurements of aquifer hydraulic parameters are expensive and difficult. Traditionally, these parameters have been estimated by graphical methods that are approximate and time-consuming. As a result, nonlinear programming (NLP) techniques have been used extensively to estimate them. Despite the outperformance of NLP approaches over graphical methods, they tend to converge to local minima and typically suffer from a convergence problem. In this study, Genetic Algorithm (GA) and Ant Colony Optimization (ACO) methods are used to identify...
A novel reciprocating micropump based on Lorentz force
, Article Progress in Biomedical Optics and Imaging - Proceedings of SPIE, 7 February 2015 through 9 February 2015 ; Volume 9320 , 2015 ; 16057422 (ISSN) ; 9781628414103 (ISBN) ; Hakimsima, A ; Shafii, M. B ; Sharif University of Technology
SPIE
2015
Abstract
Lorentz force is the pumping basis of many electromagnetic micropumps used in lab-on-a-chip. In this paper a novel reciprocating single-chamber micropump is proposed, in which the actuation technique is based on Lorentz force acting on an array of microwires attached on a membrane surface. An alternating current is applied through the microwires in the presence of a magnetic field. The resultant force causes the membrane to oscillate and pushes the fluid to flow through microchannel using a ball-valve. The pump chamber (3 mm depth) was fabricated on a Polymethylmethacrylate (PMMA) substrate using laser engraving technique. The chamber was covered by a 60 μm thick hyper-elastic latex rubber...
Shear-rate-dependent rheology effects on mass transport and surface reactions in biomicrofluidic devices
, Article AIChE Journal ; Volume 61, Issue 6 , 2015 , Pages 1912-1924 ; 00011541 (ISSN) ; Amini, Y ; Saidi, M. H ; Yavari, H ; Sharif University of Technology
John Wiley and Sons Inc
2015
Abstract
Consideration is given to shear-rate-dependent rheology effects on mass transport in a heterogeneous microreactor of rectangular cross section, utilizing both numerical and analytical approaches. The carrier liquid obeys the power-law viscosity model and is actuated primarily by an electrokinetic pumping mechanism. It is discovered that, considering the shear-thinning biofluids to be Newtonian fluids gives rise to an overestimation of the saturation time. The degree of overestimation is higher in the presence of large Damkohler numbers and electric double layer thicknesses. It is also increased by the application of a favorable pressure gradient, whereas the opposite is true when an opposed...
Economic optimization of heat pump-assisted distillation columns inmethanol-water separation
, Article Energy ; Volume 80 , 2015 , Pages 496-508 ; 03605442 (ISSN) ; Jafari, M ; Kasiri, N ; Ivakpour, J ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
Finding efficient alternative to CDiC (Conventional Distillation Column) for methanol-water separation has been an attractive field of study in literature. In this work, five heat pump-assisted schemes are proposed and compared to each other to find the optimal one; (1) VRC (Vapor Recompression Column), (2) external HIDiC (Heat-Integrated Distillation Column), (3) intensified HIDiC with feed preheater, (4) double compressor intensified HIDiC-1, and (5) double compressor intensified HIDiC-2. GA (Genetic Algorithm) is then implemented for optimization of the schemes when TAC (Total Annual Cost) is its objective function. During optimization, two new variables are added for using only...