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Optimisation of MSF Desalination Process for Fixed Water Demand using gPROMSSowgath, Md Tanvir, Mujtaba, Iqbal 21 February 2008 (has links)
Yes / Simultaneous optimisation of design and operating parameters of MSF
desalination process is considered here using MINLP technique within
gPROMS software. For a fixed fresh water demand throughout the year and
with seasonal variation of seawater temperature, the external heat input (a
measure of operating cost) to the process is minimised. It is observed that
seasonal variation in seawater temperature results in significant variation in
design with minimum variation in operating conditions in terms of process
temperatures. The results also reveal the possibility of designing stand-alone
flash stages which would offer flexible scheduling in terms of the connection of
various units (to build up the process) and efficient maintenance of the units
throughout the year as the weather condition changes. In addition, operation at
low temperatures throughout the year will reduce design and operating costs in
terms of low temperature materials of construction and reduced amount of antiscaling
and anti-corrosion agents.
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Optimisation of design and operation of MSF desalination process using MINLP technique in gPROMSSowgath, Md Tanvir, Mujtaba, Iqbal 03 1900 (has links)
No / Optimal design and operation of MSF desalination process is considered here using MINLP technique within
gPROMS model builder 2.3.4. gPROMS provides an easy and flexible platform to build a process flowsheet
graphically and the corresponding master model connecting automatically individual unit model equations during
simulation and optimisation. For different freshwater demand throughout the year and with seasonal variation of
seawater temperature, the total annualised cost of desalination is minimised. It is found that seasonal variation in
seawater temperature results in significant variation in design and some of the operating parameters but with
minimum variation in of process temperatures. The results also reveal the possibility of designing stand-alone
flash stages which would offer flexible scheduling in terms of the connection of various units (to build up the process)
and efficient maintenance of the units throughout the year as the weather condition changes. In addition, operation
at low temperatures throughout the year will reduce design and operating costs in terms of low temperature materials
of construction and reduced amount of anti-scaling and anti-corrosion agents.
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Migration Stimulating Factor : the search for inhibitorsFlorence, Margaret Mary January 2013 (has links)
The oncofetal protein Migration Stimulating Factor (MSF) is a truncated isoform of human fibronectin which exhibits numerous bioactivities that are pertinent to cancer progression. The MSF protein (70kDa) has potent motogenic activity, with only femtomolar concentrations required to produce half-maximal. The proteolytic degradation of MSF generates the functionally equivalent 43kDa Gel-BD domain and 21kDa IGD peptide. The screening of conditioned medium (CM) for bioactivity revealed two sources of MSF-inhibitory (MSF-I) activity; the spontaneously immortalised human keratinocyte cell line (HaCaT) and endothelial cells (ENDO 742) specifically when exhibiting a cobblestone phenotype. The CM from the HaCaT keratinocyte line was fractionated by both molecular weight and ionic charge, followed by sequence analysis which identified the inhibitor as Neutrophil Gelatinase Associated Lipocalin (NGAL). Both recombinant and cell-produced NGAL neutralise the motogenic activity of MSF. This novel bioactivity for NGAL is not dependent on its iron transportation capability or direct binding to MSF. HaCaT cells also secrete MSF; the bioactivity of which is masked by the co-expression of NGAL. The relative expression levels of the pro- and anti-motogenic factors, MSF and NGAL, were assessed using an in vitro model for human skin carcinogenesis, the HaCaT –ras clones. The shift in tumorigenic potential from benign to metastatic was characterised by a decrease in NGAL and an increase in MSF expression, indicating their potential role in tumour progression. The protein responsible for the MSF inhibitory activity is cell- type specific; NGAL is not expressed by endothelial cells in vitro. MSF stimulates the generation of sprouting endothelial cells from a cobblestone monolayer and acts a survival factor for spontaneously sprouting cells within a 3D matrix. NGAL does not selectively the target sprouting phenotype of endothelial cells, but induces apoptosis in all endothelial cells. Fractionation of endothelial CM revealed that both sprouting and cobblestone cells express bioactive MSF and a MSF-I. Endothelial MSF-I was located in fractions of MW 70kDa, 40kDa and =25kDa; further investigation is required to identify the protein responsible.
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MSF process modelling, simulation and optimisation : impact of non-condensable gases and fouling factor on design and operation : optimal design and operation of MSF desalination process with non-condensable gases and calcium carbonate fouling, flexible design operation and scheduling under variable demand and seawater temperature using gPROMSSaid, Said Alforjani R. January 2012 (has links)
Desalination is a technique of producing fresh water from the saline water. Industrial desalination of sea water is becoming an essential part in providing sustainable source of fresh water for a large number of countries around the world. Thermal process being the oldest and most dominating for large scale production of freshwater in today's world. Multi-Stage Flash (MSF) distillation process has been used for many years and is now the largest sector in the desalination industry. In this work, a steady state mathematical model of Multistage Flash (MSF) desalination process is developed and validated against the results reported in the literature using gPROMS software. The model is then used for further investigation. First, a steady state calcium carbonate fouling resistance model has been developed and implemented in the full MSF mathematical model developed above using gPROMS modeling tool. This model takes into consideration the effect of stage temperature on the calcium carbonate fouling resistance in the flashing chambers in the heat recovery section, heat rejection section, and brine heaters of MSF desalination plants. The effect of seasonal variation of seawater temperature and top brine temperature on the calcium carbonate fouling resistance has been studied throughout the flashing stage. In addition, the total annual operating cost of the MSF process is selected to minimise, while optimising the operating parameters such as seawater rejected flow rate, brine recycle flow rate and steam temperature at different seawater temperature and fouling resistance. Secondly, an intermediate storage between the plant and the client is considered to provide additional flexibility in design and operation of the MSF process throughout the day. A simple polynomial based dynamic seawater temperature and different freshwater demand correlations are developed based on actual data. For different number of flash stages, operating parameters such as seawater rejected flow rate and brine recycle flow rate are optimised, while the total annual operating cost of the MSF process is selected to minimise.The results clearly show that the advantage of using the intermediate storage tank adds flexible scheduling in the MSF plant design and operation parameters to meet the variation in freshwater demand with varying seawater temperatures without interrupting or fully shutting down the plant at any time during the day by adjusting the number of stages. Furthermore, the effect of non-condensable gases (NCG) on the steady state mathematical model of MSF process is developed and implemented in the MSF model developed earlier. Then the model is used to study effect of NCG on the overall heat transfer coefficient. The simulation results showed a decrease in the overall heat transfer coefficient values as NCG concentrations increased. The model is then used to study the effect of NCG on the design and operation parameters of MSF process for fixed water demand. For a given plant configuration (fixed design) and at different seawater and steam temperatures, a 0.015 wt. % of NCG results in significantly different plant operations when compared with those obtained without the presence of NCG. Finally, for fixed water demand and in the presence of 0.015 wt. % NCGs, the performance is evaluated for different plant configurations and seawater temperature and compared with those obtained without the presence of NCG.
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Veiklos taisyklėmis pagrįsta IS projektavimo metodika / Integrating Business Rules into Software Development Process ModelLukošius, Vilius 25 May 2005 (has links)
Today’s business’s more and more depend on information systems to give them edge on competition and keep double digit growth rates needed to satisfy shareholders. And information systems, serving their needs, have to keep up with changing business requirements. Business Rules Approach [10] seems to be the answer to their demands, but not many service and solution providers can satisfy their needs, because there is no standard based software engineering process to efficiently provide solution to customers. This works provides methodology of integrating business rules approach into existing and time proven software development process as well as providing needed infrastructure to creating solution specification and integrating externalized business rules with created system specification. This work concentrates on tasks: 1. Creating business rules management model; 2. Selecting software development process, adaptable to business rules approach; 3. Integrating business rules management model into selected software development process; 4. Relating externalized business rules with specification entities; 5. Providing comparison of unmodified software process with provided proposal.
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Trihalomethane compounds in the drinking water of Kuwait : a survey from source to consumerLatif, Nidhal Abbas Abdul January 1991 (has links)
A comprehensive survey of the presence of trihalomethane (THM) compounds, as chlorination by-products, in drinking water in Kuwait have been performed. The survey covers the whole drinking water treatment cycle, starting with sea water and ending with the consumer tap. The data generated by the survey was all derived from actual water treatment plants, operating under normal conditions. All four trihalomethane compounds, namely; chloroform (CHCI3), bromodichloromethane (CHBrCI2), dibromochloromethane (CHBr2CI) and bromoform (CHBr3) were covered. The study clearly showed that, although considerable amounts of THM compounds did form as a result of chlorination of sea water entering the multi-stage flash (MSF) distillation plants, these plants were highly efficient in removing these compounds. The average removal efficiency, based on THM compounds mass load in the sea water feed, was around 95%. Factors which were found to have an influence on the degree of formation of these compounds, include, chlorination practice (continuous vs. shock), sea water temperature, level of organic precursors and contact time. Of much more important consequence, as far as the presence of these compounds in drinking water is concerned, was the degree of THM compounds formation as a result of the chlorination of drinking water before it is pumped to the consumer. Here, not only all the compounds formed remain in the water but there is a definite tendency for continuous formation well after the actual chlorination process has taken place. Factors which were found affecting this formation include water temperature, contact time and chlorination dosage. Although, all samples collected showed that the presence of THM compounds was always below the United States Environmental Protection Agency maximum contaminant level of 100 ~g/L, a need exists for the optimization of all chlorination processes with particular emphasis on the chlorination of drinking water. In almost all kinds of water encountered in this study, bromoform was found to be by far the most dominant compound.
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Microstructural Behavior And Multiscale Structure-Property Relations For Cyclic Loading Of Metallic Alloys Procured From Additive Manufacturing (Laser Engineered Net Shaping -- LENS)Bagheri, Mohammad Ali 08 December 2017 (has links)
The goal of this study is to investigate the microstructure and microstructure-based fatigue (MSF) model of additively-manufactured (AM) metallic materials. Several challenges associated with different metals produced through additive manufacturing (Laser Enhanced Net Shaping – LENS®) have been addressed experimentally and numerically. Significant research efforts are focused on optimizing the process parameters for AM manufacturing; however, achieving a homogenous, defectree AM product immediately after its fabrication without postabrication processing has not been fully established yet. Thus, in order to adopt AM materials for applications, a thorough understanding of the impact of AM process parameters on the mechanical behavior of AM parts based on their resultant microstructure is required. Therefore, experiments in this study elucidate the effects of process parameters – i.e. laser power, traverse speed and powder feed rate – on the microstructural characteristics and mechanical properties of AM specimens. A majority of fatigue data in the literature are on rotation/bending test of wrought specimens; however, few studies examined the fatigue behavior of AM specimens. So, investigating the fatigue resistance and failure mechanism of AM specimens fabricated via LENS® is crucial. Finally, a microstructure-based MultiStage Fatigue (MSF) model for AM specimens is proposed. For calibration of the model, fatigue experiments were exploited to determine structure-property relations for an AM alloy. Additional modifications to the microstructurally-based MSF Model were implemented based on microstructural analysis of the fracture surfaces – e.g. grain misorientation and grain orientation angles were added to the MSF code.
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Dynamic modelling and simulation of industrial scale multistage flash desalination processHasan, Hasan, Alsadaie, S., Al-Obaidi, Mudhar A.A.R., Mujtaba, Iqbal 13 July 2023 (has links)
Yes / Multistage Flash (MSF) desalination process is still a dominant process, especially in the Gulf region, to produce high quality freshwater. Although there has been energy price surge in recent years, MSF process will continue to operate in that region for some foreseeable future. The key challenge is how to make such processes still profitable. Understanding the dynamics of any processes under uncertainty and disturbances is very important to make a process operationally feasible and profitable. The main aim of this work is to understand the dynamics of industrial scale MSF process using high fidelity and reliable process model. For this purpose, a detailed dynamic model for the MSF process incorporating key and new features is developed and validated against the actual data of a large-scale seawater desalination plant. The model is then used to study the behaviour of large scale MSF processes for disturbances in steam temperature, feed temperature and the recycle brine flow rate. The simulation results show that the last stage requires a longer time to settle compared to the preceding stages. In addition, steam temperature shows insignificant influence on the performance ratio compared to the inlet seawater temperature and recycle brine flow rate. Furthermore, it is found that the productivity of plant can increase in the winter compared to that in the summer. However, this benefit comes at the expense of increased steam consumption in the winter, resulting in a low performance ratio.
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MSF process modelling, simulation and optimisation : impact of non-condensable gases and fouling factor on design and operation. Optimal design and operation of MSF desalination process with non-condensable gases and calcium carbonate fouling, flexible design operation and scheduling under variable demand and seawater temperature using gPROMS.Said, Said Alforjani R. January 2012 (has links)
Desalination is a technique of producing fresh water from the saline water. Industrial desalination of sea water is becoming an essential part in providing sustainable source of fresh water for a large number of countries around the world. Thermal process being the oldest and most dominating for large scale production of freshwater in today¿s world. Multi-Stage Flash (MSF) distillation process has been used for many years and is now the largest sector in the desalination industry.
In this work, a steady state mathematical model of Multistage Flash (MSF) desalination process is developed and validated against the results reported in the literature using gPROMS software. The model is then used for further investigation.
First, a steady state calcium carbonate fouling resistance model has been developed and implemented in the full MSF mathematical model developed above using gPROMS modeling tool. This model takes into consideration the effect of stage temperature on the calcium carbonate fouling resistance in the flashing chambers in the heat recovery section, heat rejection section, and brine heaters of MSF desalination plants. The effect of seasonal variation of seawater temperature and top brine temperature on the calcium carbonate fouling resistance has been studied throughout the flashing stage. In addition, the total annual operating cost of the MSF process is selected to minimise, while optimising the operating parameters such as seawater rejected flow rate, brine recycle flow rate and steam temperature at different seawater temperature and fouling resistance.
Secondly, an intermediate storage between the plant and the client is considered to provide additional flexibility in design and operation of the MSF process throughout the day. A simple polynomial based dynamic seawater temperature and different freshwater demand correlations are developed based on actual data. For different number of flash stages, operating parameters such as seawater rejected flow rate and brine recycle flow rate are optimised, while the total annual operating cost of the MSF process is selected to minimise.The results clearly show that the advantage of using the intermediate storage tank adds flexible scheduling in the MSF plant design and operation parameters to meet the variation in freshwater demand with varying seawater temperatures without interrupting or fully shutting down the plant at any time during the day by adjusting the number of stages.
Furthermore, the effect of non-condensable gases (NCG) on the steady state mathematical model of MSF process is developed and implemented in the MSF model developed earlier. Then the model is used to study effect of NCG on the overall heat transfer coefficient. The simulation results showed a decrease in the overall heat transfer coefficient values as NCG concentrations increased. The model is then used to study the effect of NCG on the design and operation parameters of MSF process for fixed water demand. For a given plant configuration (fixed design) and at different seawater and steam temperatures, a 0.015 wt. % of NCG results in significantly different plant operations when compared with those obtained without the presence of NCG. Finally, for fixed water demand and in the presence of 0.015 wt. % NCGs, the performance is evaluated for different plant configurations and seawater temperature and compared with those obtained without the presence of NCG.
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Neural network based correlations for estimating temperature elevation for seawater in MSF desalination processSowgath, Md Tanvir, Mujtaba, Iqbal 09 November 2005 (has links)
No / Modelling played an important role in simulation, optimisation, and control of multi-stage flash (MSF) desalination processes. Top brine temperature (TBT) is one of the many important parameters that affect optimal design and operation of MSF processes. Within the MSF process model, calculation of TBT is therefore important. For a given pressure, TBT is a function of boiling point temperature (BPT) at zero salinity and temperature elevation (TE) due to salinity. In this work, we develop several neural network (NN) based correlations for predicting TE. It is found that the NN based correlations can predict the experimental TE very closely. Also predictions by the NN based correlations were good when TE values, obtained using existing correlations from the literature are compared. Due to advancement of the microcomputer, plant automation becomes reliable means of plant maintenance. NN based correlations (models) can be updated in terms of new sets of weights and biases for the same architecture or for a new architecture reliably with new plant data.
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