Robust controller design for multiple boilers and boiler turbine units

University of Technology, Sydney. Faculty of Engineering and Information Technology.Boilers or boiler turbine units are the main source of energy for almost every industrial installation. In most cases, the fuel cost of a power plant is a key factor in the total budget of any industrial unit. Also the major part of the running expense of any plant consists of the total fuel expense of a power plant. Due to this fact, the control of boilers and boiler turbine units confirm their significance. Improving the performance of a power plant and making it cost-effective becomes extremely important for engineers. Over the last few decades, power plant control has been the focus of attention for academic researchers, scientists and control engineers. Many innovative control techniques have been experimented with on boilers. It is seen that in order to meet the vast utility demand of the plant, more than one boiler or boiler-turbine unit is usually installed ·in a power plant. The control of such a system becomes sensitive due to the mutual dependency and interactions between one unit and another. The research reported in this thesis mostly focuses on implementing control systems with multiple boilers and multiple boiler turbine units. Hoo robust controllers are designed for systems where multiple boilers and boilerturbine units are installed and operate in parallel to each other. These controllers maintain power and steam supply in the presence of sudden changes in process parameters and external disturbances in the power plant. These days due to the vast usage of steam in a production unit, power plants consist of more than one boiler. Furthermore control of this kind of system becomes extremely sensitive when the plant is subjected to frequent variations in operating conditions. A loop shaping technique is used to synthesise robust controllers for the set point tracking, disturbance rejection and robust stability of the system against variations of the operational conditions and nonlinearity of the plant. Designed robust controllers are of high orders and, compared to PID controllers these are still not the industry favourite . That is why, to make the controllers in this study industrial favourable, these higher-order controllers are reduced to approximate the multivariable PID controllers structure. This is done for practical implementation by using eigenvalue decomposition technique. Simulation results show that the resulting PID structure displays a good robust stability and performance in the time domain, achieving steam demand and electricity demand from the boiler header and power grid stations for multiple boilers and multiple boiler-turbine units system

Capillarity in lithographically patterned micro channels

The spontaneous capillary-driven filling of micro channels is important for a wide range of applications. Reporting for the first time for vertically mounted open top channels, in this work the theory for capillary rise in channels of rectangular cross-section has been tested and verified, taking into account the effects of surface topography assuming a Wenzel state. The theory has been tested via capillary rise experiments using polydimethylsiloxane oils of viscosity 96.0, 48.0, 19.2 and 4.8 mPa s within the 400μm and 600μm closed square glass tubes and SU8 open top smooth walled rectangular cross-section channels having width 400μm and 600μm and depth 135μm. It has been shown that capillary rise heights in plane open top walled channels (with roughness factor of 1) can be fitted using the exact numerical solution and that these are similar to fits using the analytical visco-gravitational solution. The viscous friction contribution was found to be higher than predicted by theory assuming a non-rigidified liquid–air boundary, but far below that for a rigidified boundary, which is recently reported for imbibition into horizontally mounted open micro channels. It has also been observed that fingers of liquid spreading along the internal edges of the smooth walled channels in advance of the main body of liquid consistent with wetting expectations. These fingers were observed to be thicker and larger in size for wider and shallower channels

Challenges and requirements of heterogenous research data management in environmental sciences:a qualitative study

Abstract. The research focuses on the challenges and requirements of heterogeneous research data management in environmental sciences. Environmental research involves diverse data types, and effective management and integration of these data sets are crucial in managing heterogeneous environmental research data. The issue at hand is the lack of specific guidance on how to select and plan an appropriate data management practice to address the challenges of handling and integrating diverse data types in environmental research. The objective of the research is to identify the issues associated with the current data storage approach in research data management and determine the requirements for an appropriate system to address these challenges. The research adopts a qualitative approach, utilizing semi-structured interviews to collect data. Content analysis is employed to analyze the gathered data and identify relevant issues and requirements. The study reveals various issues in the current data management process, including inconsistencies in data treatment, the risk of unintentional data deletion, loss of knowledge due to staff turnover, lack of guidelines, and data scattered across multiple locations. The requirements identified through interviews emphasize the need for a data management system that integrates automation, open access, centralized storage, online electronic lab notes, systematic data management, secure repositories, reduced hardware storage, and version control with metadata support. The research identifies the current challenges faced by researchers in heterogeneous data management and compiles a list of requirements for an effective solution. The findings contribute to existing knowledge on research-related problems and provide a foundation for developing tailored solutions to meet the specific needs of researchers in environmental sciences

Level of Serum Uric Acid in Pre-eclamptic and Normal Pregnant Women

Objective: The objective of study was to find out serum uric acid level in normal andpreeclamptic pregnant women of third trimester visiting outpatient department of obstetrics and gynecology of Bahawal Victoria Hospital, Bahawalpur. Methodology: It was a cross sectional descriptive study conducted form July 2018 to June 2019. All primigravida women of age 18-35 years in third trimester of singleton pregnancy attending in Obstetrics and Gynecology Outpatient Department of Bahawal Victoria Hospital in study duration were included in the study. Statistical analysis was performed by using SPSS version 14. Chi-square test was performed to find the statistical difference regarding uric acid distribution between groups and ‘p' value <0.05 was considered as a lowest level of significance. Results: Out of total 1212 women 84.6% were normal and 15.4% had preeclampsia. In our study out of 187 preeclamptic women, 63.6% had raised serum uric acid level and out of 268 normal pregnant women uric acid level was raised in only 39.5%. Results were found statistically significant. Conclusion: Results of our study suggest that serum uric acid level in pregnant women can be used as a useful and inexpensive marker in prediction of preeclampsia and preventive measures can be taken accordingly

Effect of amino acids on inhibition of lactate dehydrogenase-X by gossypol

Gossypol acetic acid (GAA) has been shown to have male antifertility effects, but there are pronounced differences among animal species. In the search of endogenous effector molecules, which interfere with the functions of GAA, we have studied the in vitro effect of various amino acids on the inhibition of the purified LDH-X by GAA. Histidine, cysteine and glycine were shown to block the effect of GAA. The effects of these amino acids were concentration dependent. Histidine and glycine protection was found to be complex type in which both the Km and Vmax were decreased compared to control. Arginine, glutamic acid, phenylalanine and valine were found to be ineffective against the inhibitory action of GAA

Dissolved Concentrations, Sources, and Risk Evaluation of Selected Metals in Surface Water from Mangla Lake, Pakistan

The present study is carried out for the assessment of water quality parameters and selected metals levels in surface water from Mangla Lake, Pakistan. The metal levels (Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, Pb, Sr, and Zn) were determined by flame atomic absorption spectrophotometry. Average levels of Cd, Co, Cr, Ni, and Pb were higher than the allowable concentrations set by national and international agencies. Principal component analysis indicated significant anthropogenic contributions of Cd, Co, Cr, Ni, and Pb in the water reservoir. Noncarcinogenic risk assessment was then evaluated using Hazard Quotient HQing/derm and Hazard Index HIing/derm following USEPA methodology. For adults and children, Cd, Co, Cr, and Pb HQing>1 emerged as the most important pollutants leading to noncarcinogenic concerns via ingestion route, whereas there was no risk via dermal contact of surface water. This study helps in establishing pollutant loading reduction goal and the total maximum daily loads, and consequently contributes to preserve public health and develop water conservation strategy

Percutaneous coronary intervention in unprotected left main coronary artery disease

Percutaneous coronary intervention for unprotected left main coronary artery disease is potentially an important intervention in surgically unstable patients. A detailed review of medical record and visual analysis of coronary angiography and PCI procedure was undertaken. The study was conducted at the Aga Khan University Hospital, from January 2003 to December 2007. Patients included in the study had unprotected \u3e 70% left main stenosis with ongoing ischemia, considered unsuitable for surgical revascularization. A total of 9 patients were included with a mean age of 70.1 years. Six patients had cardiogenic shock. Eight patients had bifurcation lesion. Simultaneous kissing stenting technique was used in 4 patients. There were 4 in-hospital deaths while 5 patients were alive at discharge. All 4 patients who expired had cardiogenic shock. Four patients were alive at a mean follow-up of 17 months. PCI turned out to be an alternative therapeutic option for unprotected left main coronary artery disease when surgery is declined

Anaemia in pregnancy: occurrence in two economically different clinic populations of Karachi

According to previous WHO standards, anaemia in pregnancy denoted a haemoglobin level of 11.0 gms/dl or less, but this is now considered to be variable1 as it differs from country to country depending on local reference ranges and socio-economic conditions. Each country should “lay down minimal acceptable standards” below which an individual is considered to be anaemic, taking into account the available fmancial and manpower resources and other health needs of the country2. There is a wide divergence in the quoted prevalence of anaemia in Pakistan and neigh­bouring countries.3-6 This study was undertaken to determine a range of haemoglobin levels and frequency of anaemia in pregnancy in 2 clinic populations of Karachi. This study emphasises the relationship between anaemia and socio-economic levels of the population

Efficacy of Protein, Symbiotic and Probiotic Supplementation on Body Performance and Organs Weight in Molted Layers

Two hundred White Leg Horn Layers (70 week age) were arranged and brought to the poultry research station, Department of Physiology and Pharmacology, University of Agriculture, Faisalabad. Four groups were made (n=50 each) into keeping G1 as control (CP 16%, No other supplement), G2 (CP 18% diet), G3 (CP16% diet; symbiotic @ 85 mg L-1/day) and G4 (CP 16% diet; probiotic @ 85 mg L-1/day). The body and organs (heart, liver, spleen, kidney, brain and pituitary) weight from fifteen birds in each group at 5% (5P), peak (PP) and end (EP) of post molt production stage were determined. The overall mean heart weight in G2 and pituitary weight in G2 and G3 reduced (P≤0.05) as compared to G1. The mean kidney weight found increased (P≤0.05) in G3 and G4 as compared to G1. The results show metabolic relation of protein and probiotics with body organs