Analysis of wind driven self-excited induction generator supplying isolated DC loads

AbstractThis paper presents the analysis, modelling and simulation of wind-driven self-excited induction generator (SEIG). The three-phase SEIG is driven by a variable-speed prime mover to represent a wind turbine. Also, the paper investigates the dynamic performance of the SEIG during start-up, increasing or decreasing the load or rotor speed. The value of the excitation capacitance required for the SEIG is calculated to give suitable saturation level to assure self-excitation and to avoid heavy saturation levels. Matching of the maximum power available from the wind turbine is performed through varying the load value. The effect of AC–DC power conversion on the generator is investigated. The system simulation is carried out using MATLAB/SIMULINK toolbox program

Nε-(Carboxymethyl)lysine and Coronary Atherosclerosis-Associated Low Density Lipoprotein Abnormalities in Type 2 Diabetes: Current Status

In comparison to the general population, individuals with diabetes suffer a 3- to 4-fold increased risk for developing complications of atherosclerosis and vascular insufficiency. This fact should be taken into account to develop a suitable determinant for the early detection of these complications and subsequently reduce the adverse effect of type 2 diabetes. In vitro experiments have shown that the products of glucose auto-oxidation and Amadori adducts are both potential sources of Nε-(carboxymethyl)lysine (CML). Excessive formation of CML on low density lipoprotein (LDL) has been proposed to be an important mechanism for the dyslipidemia and accelerated atherogenesis observed in patients with type 2 diabetes. It has been postulated that the uptake of CML-LDL by LDL receptors is impaired, thereby decreasing its clearance from the blood circulation. Alternatively, the uptake of these modified LDL particles by scavenger receptors on macrophages and vascular smooth muscle cells (SMCs) and by AGE receptors on endothelial cells, SMCs, and monocytes is highly enhanced and this, in turn, is centrally positioned to contribute to the pathogenesis of diabetic vascular complications especially coronary artery disease. The present review summarizes the up-to-date information on effects and mechanism of type 2 diabetes-associated coronary atherosclerosis induced by CML-LDL modification

Role of Nε-(Carboxymethyl)Lysine in the Development of Ischemic Heart Disease in Type 2 Diabetes Mellitus

This study aims to determine the levels of Nε-(carboxymethyl)lysine (CML) in patients with Type 2 diabetic patients with and without ischemic heart disease (IHD) and to find for a possible association between circulating CML and a number of clinical parameters including lipids, hemoglobin A1c (HbA1c) and malondialdehyde (MDA) in Type 2 diabetic IHD patients. Serum CML levels were measured by enzyme-linked immunosorbent assay using polyclonal anti-CML antibodies. Serum levels of CML and MDA were assessed in 60 IHD patients with Type 2 diabetes, 43 IHD patients without Type 2 diabetes, 64 Type 2 diabetics without IHD, and 80 sex- and age-matched healthy subjects. Correlations studies between CML levels and lipids, HbA1c, and lipid peroxidation were performed in Type 2 diabetes patients with and without IHD. A statistical significance was observed in the levels of serum glucose, lipids (triglyceride, total cholesterol, HDL-cholesterol), MDA, HbA1c, CML and LDL-cholesterol (p<0.05) between the groups of the study. CML levels were significantly increased in diabetic IHD patients compared with Type 2 diabetes patients but without IHD (537.1 ± 86.1 vs 449.7 ± 54.9, p<0.001). A positive correlation was observed between serum levels of CML and MDA, r = 0.338 (p = 0.008) in Type 2 diabetes patients with IHD. However, age, HbA1c and lipids had no significant influence on CML levels among diabetics (p>0.05). In conclusion, this study demonstrates the effect of both diabetes and oxidative stress on the higher levels of circulating CML. These results showed that increased serum levels of CML are associated with the development of IHD in Type 2 diabetes mellitus

Tissue trauma and inflammatory response following laparoscopic versus abdominal hysterectomy: a prospective randomized clinical trial

Background: Laparoscopic surgery is associated with more favorable clinical outcome than conventional open surgery. This might be related to the magnitude of tissue trauma and tissue stress response. This study compares the intensity of tissue injury by assessing plasma C-reactive protein (CRP), lactic dehydrogenase (LDH), and cancer antigen 125 (CA 125) in patients undergoing laparoscopic hysterectomy compared to abdominal hysterectomy.Methods: This study was conducted at Ain Shams University Maternity Hospital from May 2018 to February 2020. 74 women candidate for hysterectomy were recruited and randomized into two groups: group A included 37 cases who underwent abdominal hysterectomy, and group B included 37 cases that underwent laparoscopic hysterectomy.Results: CRP, LDH and CA125 significantly increased post-operatively in both groups. Postoperative mean serum CRP, LDH and CA125 were significantly higher in the laparotomy group (10.84±2.47, 262.21±76.77, and 13.41±2.6 respectively) compared to laparoscopy group (7.92±2.25, 148.53±43.56, 11.79±2.77 respectively) (p<0.05).Conclusions: Surgery is a significant cause of tissue injury that can be assessed by specific markers. We suggest that laparoscopic surgery causes less tissue damage as assessed by lower postoperative CRP and LDH values, which might account for the earlier recovery and reduced hospital stay in laparoscopic surgery

Importance and Significance of UF/MF Membrane Systems in Desalination Water Treatment

The proposed chapter addresses a comprehensive overview of the history and future outlook of ultrafiltration/microfiltration (UF/MF) membrane for desalination water pretreatment. Known theories on UF/MF membrane formation from phase inversion (Dr/wet) systems can be prolonged to define the consequences of high or low molecular weight additives. Also, direct material reengineering and surface modification for high-performance anti-fouling of UF/MF membranes are also highlighted. Before the modern final polymeric film, the characterization techniques, particularly molecular weight cut-off, pore size, pore size distribution, and microbiological activity classification, on to the UF/MF membrane surface were presented, respectively. Lab scale to commercial scale UF/MF membrane configuration and market size of UF/MF membranes for pretreatment desalination are described. The significance of UF/MF provided here as an unconventional approach for desalination water pretreatment is in contrast with the current conventionally used technologies. The recent development made in the integration of established desalination processes, such as spiral wound reverse osmosis (SWRO), multi-stage flash (MSF), multi-effect distillation (MED), electrodialysis (ED) desalination, and UF pretreatment, is addressed. Finally, the influence of UF/MF on desalination water pretreatment step on to the energy cost of desalination process system is discussed

Agent Productivity Modeling in a Call Center Domain Using Attentive Convolutional Neural Networks

Article numbre 5489Measuring the productivity of an agent in a call center domain is a challenging task. Subjective measures are commonly used for evaluation in the current systems. In this paper, we propose an objective framework for modeling agent productivity for real estate call centers based on speech signal processing. The problem is formulated as a binary classification task using deep learning methods. We explore several designs for the classifier based on convolutional neural networks (CNNs), long-short-term memory networks (LSTMs), and an attention layer. The corpus consists of seven hours collected and annotated from three different call centers. The result shows that the speech-based approach can lead to significant improvements (1.57% absolute improvements) over a robust text baseline system

Ownership structure and firm performance: Evidence manufacturing companies listed in Dhaka Stock Exchange

Purpose: This study aims at examining the relationship between ownership structure and firm performance about manufacturing companies listed in Dhaka Stock Exchange (DSE). Research Methodology: The analysis empirically uses dynamic panel data from 15 pharmaceutical and chemical companies enlisted in Dhaka Stock Exchange (DSE). The study period was 2011-2020. The study used panel data regression analysis. Results: The study confirms that sampled companies' financial performance represented by ROA and ROE is significantly influenced by institutional ownership, ownership concentration, and foreign ownership whereas, negatively influenced by managerial ownership and insider ownership. The study didn't find any noteworthy association between block holders' ownership with firms' performance. Contribution: This study keeps a significant role in understanding the ownership structures’ influence on firms’ performance. More specifically the policymakers may consider the study for implementing the relevant issues. Limitations: The study's results were restricted to 15 Bangladeshi pharmaceutical and chemical companies enlisted in DSE and could not be applied to other companies doing business in Bangladesh

Neuromorphic Computing between Reality and Future Needs

Neuromorphic computing is a one of computer engineering methods that to model their elements as the human brain and nervous system. Many sciences as biology, mathematics, electronic engineering, computer science and physics have been integrated to construct artificial neural systems. In this chapter, the basics of Neuromorphic computing together with existing systems having the materials, devices, and circuits. The last part includes algorithms and applications in some fields