Distributed Control and State Estimation of DC Microgrids Based on Constrained Communication Networks.

PhD ThesesThe intermittent nature of renewable energy sources (RES) such as wind turbines and photovoltaic panels, requires advanced control systems to provide the balance between energy supply and demand in any power system. For better management of power quality and security issues, energy storage systems (ESSs) are deployed to compensate for the temporary mismatch of supply and demand. Furthermore, in rural areas with no connection to the main grid, ESSs such as batteries are deployed in large quantities as a solution for temporary power stabilization during RES unavailability. However, the control complexity of the power system increases as more ESSs are getting installed due to the need for coordination of the power transfer among them. This thesis undertakes a thorough analysis of distributed control and state estimation designs for direct current (DC) microgrids with ESSs based on constrained communication networks. The developed distributed control and estimation strategies are designed for operation over constrained communication networks. They don't require a central coordinator for synchronization of the control tasks between the ESSs. This forms a multi-agent environment where the controllers cooperatively achieve the DC microgrid objectives, i.e. voltage stabilization, proportional power-sharing, and balancing of ESSs' energy level. To overcome the communication network constraints, event-based controllers and estimators are designed, which e ectively reduce the network tra c and as a result, provide higher throughput with reduced delays for the real-time control loops of the DC microgrids. The controllers are designed to be distributed, leading to use cases such as autonomous islanded microgrids, smart villages, and plug-and-play mobile microgrids. The feasibility and performance of the proposed control and estimation strategies are con rmed in several experimental test benches by showing the higher reliability and robustness in the delivered power quality. The results have shown considerable reduction in the network tra c, meanwhile the control system provided high performance in terms of stability, robustness, power quality and endurabilit

A novel distributed privacy-preserving control and data collection method for IoT-centric microgrids

Abstract The privacy of electricity consumers has become one of the most critical subjects in designing smart meters and their proliferation. In this work, a multilayer architecture has been proposed for anonymous data collection from smart meters, which provides: (1) The anonymity of information for third‐party data consumers; (2) Secure communication to utility provider network for billing purposes; (3) Online control of data sharing for end‐users; (4) Low communication costs based on available Internet of things (IoT) communication protocols. The core elements of this architecture are, first, the digital twin equivalent of the cyber‐physical system and, second, the Tangle distributed ledger network with IOTA cryptocurrency. In this architecture, digital twin models are updated in real‐time by information received from trusted nodes of the Tangle distributed network anonymously. A small‐scale laboratory prototype based on this architecture has been developed using the dSPACE SCALEXIO real‐time simulator and open‐source software tools to prove the feasibility of the proposed solution. The numerical results confirm that after a few seconds of anomaly detection, the microgrid was fully stabilized around its operating point with less than 5% deviation during the transition time

Investigating Dynamic Properties of Residues of Warfarin-Azapropazone Binding Site in Human Serum Albumin

Introduction: Human Serum Albumin is one of the most important proteins in blood that can bind a wide range of components and different drugs such as Warfarin. Therefore, studying human serum albumin is very significant in pharmacology. In this research, dynamic behavior of residues of Warfain binding site of human serum albumin was investigated. Method: First, three-dimensional format of human serum albumin (PDB ID: 4G04) was downloaded from RCSB. Then, using GROMACS package, molecular dynamics simulation has been done on chain A of crystallography structure during 30ns. Results: RMSD analysis on residues of binding site showed that Arginines 186 and 218 have wide fluctuations in their RMSD plot. Also, Lysines 185 and 190 have nearly wide fluctuations of RMSD; however, these fluctuations were less than Arginine's. Other residues such as Glycine 189 have few fluctuations. Fluctuations in RMSD have direct relationship with accessible surface area of the residues. Conclusion: The results show that Warfarin binding site in human serum albumin can have various conformational situations because of the dynamics of its residues. This can be important in drug design. Overall, according to the results of this study, residues are divided into 3 categories. Among them, Tryptophan 214, that is one of the most important residues according to different studies, was placed in the category of residues with the least mobility

A new design equation for prediction of ultimate bearing capacity of shallow foundation on granular soils

A major concern in design of structures is to provide precise estimations of ultimate bearing capacity of soil beneath their foundations. Direct determination of the bearing capacity of foundations requires performing expensive and time consuming laboratory tests. To cope with this issue, several numerical models have been presented by researchers. This paper presents the development of a new design equation for the prediction of the ultimate bearing capacity of shallow foundations on granular soils using linear genetic programming (LGP) methodology. The ultimate bearing capacity is formulated in terms of width of footing, footing geometry, depth of footing, unit weight of sand, and angle of shearing resistance. The LGP-based design equation is established using the results of several load tests on real sized foundations presented in the literature. Validity of the model is verified using a part of laboratory data that are not involved in the calibration process. The statistical measures of coefficient of determination, root mean squared error and mean absolute error are used to evaluate the performance of the model. Sensitivity and parametric analyses are conducted and discussed. The proposed model accurately characterizes the ultimate bearing capacity resulting in a very good prediction performance. The LGP model reaches a better prediction performance than the well-known prediction equations for the bearing capacity of shallow foundations

Water Resources Management Through Flood Spreading Project Suitability Mapping Using Frequency Ratio, k-nearest Neighbours, and Random Forest Algorithms

Lack of water resources is a common issue in many countries, especially in the Middle East. Flood spreading project (FSP) is an artificial recharge technique, which is generally suggested for arid and semi-arid areas with two major aims including (1) flood mitigation and (2) artificial recharge of groundwater. This study implemented three state-of-the-art popular models including frequency ratio (FR), k-nearest neighbours (KNN), and random forest (RF) for determining the suitability of land for FSP. At the first step, suitable areas for FSP were identified according to the national guidelines and the literature. The identified areas were then verified by multiple field surveys. To produce FSP land suitability maps, several FSP conditioning factors such as topographical (i.e. slope, plan curvature, and profile curvature), hydrogeological (i.e. transmissivity, aquifer thickness, and electrical conductivity), hydrological (i.e. rainfall, distance from rivers, river density, and permeability), lithology, and land use were considered as input to the models. For the FR modelling, classified layers of the aforementioned variables were used, while their continuous layers were implemented in the KNN and RF algorithms. At the last step, receiver operating characteristic (ROC) curve was used to assess the ability and accuracy of the applied algorithms. Based on the findings, the area under the curve of ROC for the RF, KNN, and FR models was 97.1, 94.6, and 89.2%, respectively. Furthermore, transmissivity, slope, aquifer thickness, distance from rivers, rainfall, and electrical conductivity were recognized as the most influencing factors in the modelling procedure. The findings of this study indicated that the application of RF, KNN, and FR can be suggested for identification of suitable areas for FSP establishment in other regions

Improving lithium carbonate therapeutics by pegylated liposomal technology: an in vivo study

Bipolar disorder is a chronic mental illness which is associated with high risk of self-harm and suicide. Lithium carbonate has been suggested as a medicine to control and cure this disease. To overcome the complications related to taking lithium carbonate, nanotechnology has come to the aid of scientists. In this study, pegylated liposomal lithium carbonate nanoparticles were prepared by the reverse phase evaporation method to improve the drug’s therapeutic characteristics as well as lessening its side effects. In order to synthesize pegylated liposomal lithium carbonate, phosphatidylcholine, polyethylene glycol 3350 (PEG3350), cholesterol, and lithium carbonate were mixed. The characterization of synthesized nanoparticles was determined by Zetasizer. Encapsulation and drug loading efficiency and release pattern studies were determined through spectrophotometry method. In addition, serum lithium and creatinine levels of the samples were analyzed. The mean diameter, size distribution, and zeta potential for pegylated liposomal particles containing lithium carbonate and blank pegylated liposomal were determined by Zetasizer equal to 102\ua0nm, 0.458, and −25.1\ua0mV; 284.2\ua0nm, 0.427, and −28.3\ua0mV, respectively. Drug loading and encapsulation efficiency were calculated to be 32.87 and 97.4\ua0%, respectively. The drug release pattern demonstrated that the half-life of the nanodrug was approximately two times higher than the standard drug. The results related to the analysis of serum lithium and creatinine levels indicated that the efficiency of liposomal drug formulation was increased compared to the standard drug. Based on the findings, the nanodrug enjoyed a half-life two times higher than that of the standard drug and an efficiency level equal to it

Analysis of the effects of some surface preparation methods on the bond strength of orthodontic attachments to amalgam surface

This in-vitro research was aimed to examine the shear bond strength of metal brackets to silver amalgam using various surface preparation techniques to determine the best method to achieve appropriate bond strength between bracket and amalgam surface. Ninety amalgam blocks were divided into six groups and randomly assigned to one of the following conditioning groups (n=15): group 1 (control): etching with 37% phosphoric acid for 20 seconds, group 2: sand blasting with aluminum oxide (Al2O3), group 3: CO2 laser, group 4: CO2 laser plus sand blast, group 5: Er:YAG laser and group 6:Er:YAG laser plus sandblast. All Bond II was used in all groups and brackets were bonded with Transbond XT. After thermocycling, all samples were tested for shear bond strength by a universal testing machine. Data were analyzed by SPSS-22 software using Kruskal-Wallis and Mann-Whitney tests. The significance level was set at p <= 0.05.The results showed the mean shear bond strength was significantly higher in all five experimental groups than in control group (p <= 0.05). Shear bond strength was significantly higher in CO2 + sandblasting group than in sandblast group, but it was not significantly higher than Er:YAG,Er:YAG + sandblast and CO2 groups. Moreover, the results indicated a significantly higher shear bond strength in Er:YAG group than in sandblast group (p <= 0.05). Preparation by CO2 + sandblast (with mean shear bond strength of 6.3 Mpa) showed a higher shear bond strength than other methods, so it is considered an acceptable preparation method. Keywords:Surface treatment; amalgam; CO2 laser; Er:YAG laser; shear bond strengt

Pemphigoid Gestationis: A Retrospective Study in Southwest Iran

Pemphigoid gestationis (PG) is a rare autoimmune bullous dermatosis of pregnancy usually presents in the second or third trimester. It is characterized by pruritic, urticarial plaques with the development of tense vesicles and bullae within the lesions. Pathogenesis of PG is not fully established, however, most patients develop circulating autoantibodies targeting the bullous pemphigoid (BP) 180 antigen. The aim of this work is to draw a profile of the epidemiology, clinical aspects, treatment and evolution of the disease by studying hospital series. We retrospectively investigated the 13 patients who were diagnosed with PG based on hospital data at the Referral Center of Southwest Iran located in Ahvaz city between March 2002 and March 2011. The age of onset was 21 to 40 years (mean age: 27.5 years). The onset of the disease occurred in the second trimester of pregnancy in 6 patients and in the third trimester of pregnancy in 4 patients. One patient had a flare up of disease during the first trimester and two out of cases in puerperium period. In all cases, pruritus was the first symptom, followed by an erythematous vesiculobullous eruption.  The diagnosis of PG was confirmed by skin biopsy. Ten out of the patients treated with oral corticosteroids (0.5-1 mg/kg/day), one of the patients underwent oral corticosteroids plus topical glucocorticoid and the last patient treated with topical glucocorticoid. PG remains a rare dermatosis of pregnancy. Our series had two particularities compared to other studies: high frequency in primigravida and the frequent involvement of the face. Additionally our study demonstrated that improvement could occur faster and provide acceptable management if the treatment of the patients would be implemented sooner