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Reliability and Probabilistic Seismic Assessment of Fixed Jacket Type Offshore Platforms
,
M.Sc. Thesis
Sharif University of Technology
;
Golafshani, Ali Akbar
(Supervisor)
Abstract
This thesis encompasses a number of issues in earthquake engineering which may appear quite diverse in nature. Several methodological aspects of both conventional and novel approaches to probabilistic seismic hazard assessment are discussed here along with subjects more strictly pertinent to structural and geotechnical engineering. This work, however, has a unique, ultimate goal: to provide procedures for an effective and practical probabilistic estimation of structural demand of offshore platforms due to seismic ground shaking. In modern multi-level design and rehabilitation procedures, structural performance is in fact quantified by deformation demand levels exceeded with a specified...
The Effect of Exact and Approximate Distribution of Conditional Spectrum in Probabilistic Estimation of Structural Demands
, M.Sc. Thesis Sharif University of Technology ; Golafshani, Ali Akbar (Supervisor)
Abstract
In this thesis several methodological aspects of both conventional and novel approaches to probabilistic seismic hazard assessment are discussed here along with subjects more strictly pertinent to structural and geotechnical engineering. This work, however, has a unique, ultimate goal: to provide procedures for an effective and practical probabilistic estimation of structural demand of offshore platforms due to seismic ground shaking.In modern multi-level design and rehabilitation procedures, structural performance is in fact quantified by deformation demand levels exceeded with a specified annual frequency of structural life. We refer to this as Probabilistic Seismic Demand Analysis (PSDA)....
Assessment of Existing Jaket-Type Offshore Platforms in the Persian Gulf Region for Service Life Extension or Operative Conditions
, Ph.D. Dissertation Sharif University of Technology ; Golafshani, Ali Akbar (Supervisor)
Abstract
Assessment of existing jacket-type offshore platforms in Persian Gulf for life extension or operative conditions is a major concern for oil offshore companies in recent years. Significant damage to offshore platforms as well as their contents will induce significant losses such as financial losses, fatalities and casualties. On the other hand, extreme waves or earthquakes are low-probability, large-consequence and large-uncertainty hazards that can affect these critical facilities; therefore, the assessment of existing offshore platforms subjected to each of these sources can be successfully carried out by a probabilistic approach. In this dissertation, a unique probabilistic...
Probabilistic Seismic Demand Analysis Using Endurance Time Method
, Ph.D. Dissertation Sharif University of Technology ; Esmail Pourestekanchi, Homayoon (Supervisor)
Abstract
In the field of estimating the expected performance of structures under the excitation of earthquakes of different magnitudes, the Endurance time method has been introduced as a fast method in recent years. What is needed now in this method is to study the assumptions and definitions used in this method, to choose more logical definitions, to unify them, and to prove the statistics of this method in the overlapping and generalizable range of different structures. For this purpose, in this dissertation, different definitions have been evaluated in the process of using the Endurance time method and IDA. The results of different definitions for the target time equivalent to each earthquake...
Load commitment in a smart home
, Article Applied Energy ; Vol. 96, issue , 2012 , p. 45-54 ; ISSN: 03062619 ; Fotuhi-Firuzabad, M ; Aminifar, F ; Sharif University of Technology
Abstract
Although demand response (DR) potentially brings miscellaneous advantages, it is currently faced with challenges in its implementation due to customers' difficulty in manually responding to the time-varying prices. This paper presents an optimal and automatic residential load commitment (LC) framework to achieve the household minimum payment. Problem decision variables are the operating status of responsive appliances and charging/discharging cycles of battery storage and plug-in hybrid electric vehicles (PHEVs). Storage capability in residential centers provide the customers with this opportunity to not only supply the local demand during the high price hours but also sell the energy back...
Bimodal electricity generation and aromatic compounds removal from purified terephthalic acid plant wastewater in a microbial fuel cell
, Article Biotechnology Letters ; Volume 35, Issue 2 , 2013 , Pages 197-203 ; 01415492 (ISSN) ; Kariminia, H. R ; Savizi, I. S. P ; Sharif University of Technology
2013
Abstract
Wastewater of purified terephthalic acid (PTA) from a petrochemical plant was examined in a membrane-less single chamber microbial fuel cell for the first time. Time course of voltage during the cell operation cycle had two steady phases, which refers to the fact that metabolism of microorganisms was shifted from highly to less biodegradable carbon sources. The produced power density was 31.8 mW m-2 (normalized per cathode area) and the calculated coulombic efficiency was 2.05 % for a COD removal of 74 % during 21 days. The total removal rate of different pollutants in the PTA wastewater was observed in the following order: (acetic acid) > (benzoic acid) > (phthalic acid) > (terephthalic...
Load commitment in a smart home
, Article Applied Energy ; Volume 96 , 2012 , Pages 45-54 ; 03062619 (ISSN) ; Fotuhi Firuzabad, M ; Aminifar, F ; Sharif University of Technology
Abstract
Although demand response (DR) potentially brings miscellaneous advantages, it is currently faced with challenges in its implementation due to customers' difficulty in manually responding to the time-varying prices. This paper presents an optimal and automatic residential load commitment (LC) framework to achieve the household minimum payment. Problem decision variables are the operating status of responsive appliances and charging/discharging cycles of battery storage and plug-in hybrid electric vehicles (PHEVs). Storage capability in residential centers provide the customers with this opportunity to not only supply the local demand during the high price hours but also sell the energy back...
Imperialist competitive algorithm for solving non-convex dynamic economic power dispatch
, Article Energy ; Volume 44, Issue 1 , 2012 , Pages 228-240 ; 03605442 (ISSN) ; Rabiee, A ; Soroudi, A ; Ehsan, M ; Sharif University of Technology
Abstract
Dynamic economic dispatch (DED) aims to schedule the committed generating units' output active power economically over a certain period of time, satisfying operating constraints and load demand in each interval. Valve-point effect, the ramp rate limits, prohibited operation zones (POZs), and transmission losses make the DED a complicated, non-linear constrained problem. Hence, in this paper, imperialist competitive algorithm (ICA) is proposed to solve such complicated problem. The feasibility of the proposed method is validated on five and ten units test system for a 24 h time interval. The results obtained by the ICA are compared with other techniques of the literature. These results...
Designing time-of-use program based on stochastic security constrained unit commitment considering reliability index
, Article Energy ; Volume 41, Issue 1 , May , 2012 , Pages 541-548 ; 03605442 (ISSN) ; Mozafari, B ; Bashirvand, M ; Solaymani, S ; Ranjbar, A. M ; Sharif University of Technology
2012
Abstract
Recently in electricity markets, a massive focus has been made on setting up opportunities for participating demand side. Such opportunities, also known as demand response (DR) options, are triggered by either a grid reliability problem or high electricity prices. Two important challenges that market operators are facing are appropriate designing and reasonable pricing of DR options.In this paper, time-of-use program (TOU) as a prevalent time-varying program is modeled linearly based on own and cross elasticity definition. In order to decide on TOU rates, a stochastic model is proposed in which the optimum TOU rates are determined based on grid reliability index set by the operator. Expected...
Constrained single period problem under demand uncertainty
, Article Scientia Iranica ; Volume 18, Issue 6 , December , 2011 , Pages 1553-1563 ; 10263098 (ISSN) ; Shavandi, H ; Haji, R ; Sharif University of Technology
2011
Abstract
In this paper, we develop the multi-product, multi-constraint, Single Period Problem (SPP) with uncertain demands, considering an incremental discount situation. Three new models are presented for multi-product, multi-constraint SPP in fuzzy, stochastic and rough environments. We consider constraints, such as service rate, restriction on order quantity and restrictions on warehouse space and budget. We also consider that the order quantity is a multiplier of predefined batch size. Furthermore, three kinds of solution algorithm, (1) harmony search, (2) hybrid intelligent based on harmony search and fuzzy simulation and (3) hybrid intelligent based on harmony search and rough simulation, are...
Upgrading activated sludge systems and reduction in excess sludge
, Article Bioresource Technology ; Volume 102, Issue 22 , November , 2011 , Pages 10327-10333 ; 09608524 (ISSN) ; Shayegan, J ; Sharif University of Technology
2011
Abstract
Most of 200 Activated Sludge Plant in Iran are overloaded and as a result, their efficiency is low. In this work, a pilot plant is manufactured and put into operation in one of the wastewater treatment plants in the west of Tehran. Instead of conventional activated sludge, a membrane bioreactor and an upflow anaerobic sludge blanket reactor used as a pretreatment unit in this pilot. For the sake of data accuracy and precision, an enriched municipal wastewater was opted as an influent to the pilot. Based on the attained result, the optimum retention time in this system was 4. h, and the overall COD removal efficiency was 98%. As a whole, the application of this retrofit would increase the...
Bioelectricity generation enhancement in a dual chamber microbial fuel cell under cathodic enzyme catalyzed dye decolorization
, Article Bioresource Technology ; Volume 102, Issue 12 , June , 2011 , Pages 6761-6765 ; 09608524 (ISSN) ; Kariminia, H. R ; Roshandel, R ; Sharif University of Technology
2011
Abstract
Enzymatic decolorization of reactive blue 221 (RB221) using laccase was investigated in a dual-chamber microbial fuel cell (MFC). Suspended laccase was used in the cathode chamber in the absence of any mediators in order to decolorize RB221 and also improve oxygen reduction reaction in the cathode. Molasses was utilized as low cost and high strength energy source in the anode chamber. The capability of MFC for simultaneous molasses and dye removal was investigated. A decolorization efficiency of 87% was achieved in the cathode chamber and 84% COD removal for molasses was observed in the anode chamber. Laccase could catalyze the removal of RB221 and had positive effect on MFC performance as...
A stochastic security approach to energy and spinning reserve scheduling considering demand response program
, Article Energy ; Volume 36, Issue 5 , 2011 , Pages 3130-3137 ; 03605442 (ISSN) ; Nikzad, M ; Mozafari, B ; Ranjbar, A. M ; Sharif University of Technology
Abstract
In this paper a new algorithm for allocating energy and determining the optimum amount of network active power reserve capacity and the share of generating units and demand side contribution in providing reserve capacity requirements for day-ahead market is presented. In the proposed method, the optimum amount of reserve requirement is determined based on network security set by operator. In this regard, Expected Load Not Supplied (ELNS) is used to evaluate system security in each hour. The proposed method has been implemented over the IEEE 24-bus test system and the results are compared with a deterministic security approach, which considers certain and fixed amount of reserve capacity in...
Nitrogen removal from high organic loading wastewater in modified Ludzack-Ettinger configuration MBBR system
, Article Water Science and Technology ; Volume 72, Issue 8 , October , 2015 , Pages 1274-1282 ; 02731223 (ISSN) ; Borghei, S. M ; Tahmasebian, S ; Andalibi, M. R ; Sharif University of Technology
IWA Publishing
2015
Abstract
A moving bed biofilm reactor with pre-denitrification configuration was fed with a synthetic wastewater containing high chemical oxygen demand (COD) and ammonia. By changing different variables including ammonium and COD loading, nitrification rate in the aerobic reactor and denitrification rate in the anoxic reactor were monitored. Changing the influent loading was achieved via adjusting the inlet COD (956-2,096 mg/L), inlet ammonium (183-438 mg/L), and hydraulic retention time of the aerobic reactor (8, 12, and 18 hours). The overall organic loading rate was in the range of 3.60-17.37 gCOD/m2·day, of which 18.5-91% was removed in the anoxic reactor depending on the operational conditions....
An integrated vendor-buyer model with stock-dependent demand
, Article Transportation Research Part E: Logistics and Transportation Review ; Volume 46, Issue 6 , November , 2010 , Pages 963-974 ; 13665545 (ISSN) ; Thorstenson, A ; Akbari Jokar, M. R ; Sharif University of Technology
2010
Abstract
We develop an integrated vendor-buyer model for a two-stage supply chain. The vendor manufactures the product and delivers it in a number of equal-sized batches to the buyer. The items delivered are presented to the end customers in a display area. Demand is assumed to be positively dependent on the amount of items displayed. The objective is to maximize total supply chain profit. The numerical analysis shows that buyer-vendor coordination is more profitable in situations when demand is more stock dependent. It also shows that the effect of double marginalization provides a link between the non-coordinated and the coordinated case
Multi-objective design and operation of Solid Oxide Fuel Cell (SOFC) Triple Combined-cycle Power Generation systems: Integrating energy efficiency and operational safety
, Article Applied Energy ; Volume 185 , 2017 , Pages 345-361 ; 03062619 (ISSN) ; Meghdari, M ; Rashtchian, D ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
Energy efficiency is one of the main pathways for energy security and environmental protection. In fact, the International Energy Agency asserts that without energy efficiency, 70% of targeted emission reductions are not achievable. Despite this clarity, enhancing the energy efficiency introduce significant challenge toward process operation. The reason is that the methods applied for energy-saving pose the process operation at the intersection of safety constraints. The present research aims at uncovering the trade-off between safe operation and energy efficiency; an optimization framework is developed that ensures process safety and simultaneously optimizes energy-efficiency, quantified in...
Dynamic optimization of natural gas networks under customer demand uncertainties
, Article Energy ; Volume 134 , 2017 , Pages 968-983 ; 03605442 (ISSN) ; Bozorgmehry Boozarjomehry, R ; Sharif University of Technology
Abstract
In natural gas transmission networks, the efficiency of daily operation is strongly dependent on our knowledge about the customer future demands. Unavailability of accurate demand forecasts makes it more important to be able to characterize the loads and quantify the corresponding uncertainty. A planning strategy for natural gas transmission networks under future demand uncertainty is addressed, which involves coupling of a gas transmission network dynamic simulator with the stochastic optimization framework. Loads from a gas-fired power plant are studied where the loads are characterized by a number of uncertain parameters, and unscented transform is utilized for uncertainty propagation....
Power sector development in Iran: a retrospective optimization approach
, Article Energy ; Volume 140 , 2017 , Pages 330-339 ; 03605442 (ISSN) ; Aryanpur, V ; Sharif University of Technology
Abstract
This paper provides an overview of the power sector development in Iran for the period 1984–2014. A retrospective optimization approach is applied to assess economic and environmental benefits that would have been achieved through appropriate long-term planning. MESSAGE, a systems engineering optimization model, is used for this analysis. Two alternative scenarios are defined to explore the impact of supply- and demand-side strategies on the power generation mix, fuel consumption and CO2 emissions. The focus on the past choice of energy scenarios provides some insights for future scenario design. The results of the cost-optimal scenarios with international fuel prices are compared with the...
Capacity and output power estimation approach of individual behind-the-meter distributed photovoltaic system for demand response baseline estimation
, Article Applied Energy ; Volume 253 , 2019 ; 03062619 (ISSN) ; Wang, F ; Mi, Z ; Fotuhi Firuzabad, M ; Duić, N ; Wang, T ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
Accurate customer baseline load (CBL) estimation is critical for implementing incentive-based demand response (DR) programs. The increasing penetration of grid-tied distributed photovoltaic systems (DPVS) complicates customers’ load patterns, making the CBL estimation more difficult because the volatile actual load and the intermittent PV output power are coupled together. A PV-load decoupling framework is proposed in this paper to address the above issue. The basic idea is to decouple the actual load power and the PV output power, then estimate them separately. To this end, historical PV output power data of each individual DPVS is required. However, pure historical PV output power data is...
A decision support system for demand management in healthcare supply chains considering the epidemic outbreaks: A case study of coronavirus disease 2019 (COVID-19)
, Article Transportation Research Part E: Logistics and Transportation Review ; Volume 138 , June , 2020 ; Mina, H ; Alavi, B ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
The disasters caused by epidemic outbreaks is different from other disasters due to two specific features: their long-term disruption and their increasing propagation. Not controlling such disasters brings about severe disruptions in the supply chains and communities and, thereby, irreparable losses will come into play. Coronavirus disease 2019 (COVID-19) is one of these disasters that has caused severe disruptions across the world and in many supply chains, particularly in the healthcare supply chain. Therefore, this paper, for the first time, develops a practical decision support system based on physicians' knowledge and fuzzy inference system (FIS) in order to help with the demand...