638 research outputs found

    Solvent Vapor Induced Film Formation of PS/AgNPs Composites Using Spectroscopic Techniques

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    In this work, pyrene labeled polystyrene (PS) latex dispersions and silver nanoparticles (AgNPs) were mixed at different weight ratios of AgNPS in the range of 0-50 wt%. Powder (PS/AgNPs) films were prepared on glass substrates from these mixtures by the drop-casting method at room temperature. The fast transient fluorescence (FTRF) technique was used to monitor the film formation process of PS/AgNPs composites by measuring the fluorescence lifetimes of pyrene during vapor exposure. It was observed that pyrene lifetimes decreased as vapor exposure time, t increased obeying Stern-Volmer kinetic. The optical transmission (UVV) experiments showed that the transparency of the films decreased with increasing AgNPs content. Transparent films were produced for the composites with 0 to 20 wt % of AgNPs content. The Prager-Tirrel model was employed to FTRF and UVV data to obtain back-and-forth frequencies, ν, of the reptating PS chains during vapor induced film formation process and polymer interdiffusion was found to obey a t1/2 law. Despite the conductivity increased by 3 orders of magnitude with increasing AgNPs content, the composites behaved like an insulator. The morphology of composite films also progressively changed during vapor exposure and affected by AgNPs content

    Automated Lane Change Decision Making using Deep Reinforcement Learning in Dynamic and Uncertain Highway Environment

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    Autonomous lane changing is a critical feature for advanced autonomous driving systems, that involves several challenges such as uncertainty in other driver's behaviors and the trade-off between safety and agility. In this work, we develop a novel simulation environment that emulates these challenges and train a deep reinforcement learning agent that yields consistent performance in a variety of dynamic and uncertain traffic scenarios. Results show that the proposed data-driven approach performs significantly better in noisy environments compared to methods that rely solely on heuristics.Comment: Accepted to IEEE Intelligent Transportation Systems Conference - ITSC 201

    HEMOPHILIA PATIENT WITH DIFFICULTY IN BLOOD PRESSURE CONTROL

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    Hypertension prevalence is increasing in patients with hemophilia. Therefore it is an important complication of hemophilia. We aimed to present a 49-year-old male patient with hemophilia-A who presented with acute hemarthrosis and hypertensive attack. The patient was treated in our internal medicine clinic

    MDP based Decision Support for Earthquake Damaged Distribution System Restoration

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    As the society becomes more dependent on the presence of electricity, the resilience of the power systems gains more importance. This paper develops a decision support method for distribution system operators to restore electricity after an earthquake to the maximum number of customers in the minimum expected duration. The proposed method employs Markov Decision Process (MDP) to determine the optimal restoration scheme. In order to determine the probability of the field component damage due to the earthquake, the Probability of Failure (PfP_f) of structures are calculated using the Peak Ground Acceleration (PGA) values recorded by observatories and earthquake research centers during the earthquake

    Centralized Microgrid Control System in Compliance with IEEE 2030.7 Standard Based on an Advanced Field Unit

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    The necessity for the utilization of microgrids emerges from the integration of distributed energy resources, electric vehicles, and battery storage systems into the conventional grid structure. In order to achieve a proper operation of the microgrid, the presence of a microgrid control system is crucial. The IEEE 2030.7 standard defines the microgrid control system as a key element of the microgrid that regulates every aspect of it at the point-of-interconnection with the distribution system, and autonomously manages operations such as the transitions of operating modes. In this paper, a microgrid control system is developed to achieve real-time monitoring and control through a centralized approach. The controller consists of a centralized server and advanced field units that are also developed during this work. The control functions of the centralized server ensure the proper operation during grid-connected and island modes, using the real-time data received via the advanced field unit. The developed server and the field unit constitute a complete system solution. The server is composed of control function and communication, database, and user interface modules. The microgrid control functions comprise dispatch and transition core-level functions. A rule-based core-level dispatch function guarantees the security of supply to critical loads during the islanded mode. The core-level transition function accomplishes a successful transition between the operation modes. Moreover, a communication framework and a graphical user interface are implemented. The presented system is tested through thecases based on the IEEE 2030.8 standard

    Investigation of Vitamin D Levels in Patients with Vitiligo Vulgaris

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    The aim of the study was to investigate serum 25-hydroxyvitamin D (25(OH) D3) levels in patients with vitiligo vulgaris in terms of causal relation and extension of the disorder.This study is a clinical cross-sectional study carried out in order to determine 25-hydroxyvitamin D levels among 25 patients with vitiligo vulgaris and in 41 controls. Fitzpatrick skin phototypes, history of autoimmune disease, family history of vitiligo, and duration of the disease were also evaluated.The mean levels of vitamin D in patient and the control group were 15.2±5.2 ng/dL and 14.4±6.2 ng/dL respectively (P&gt;0.05). In our study, 48% of the patients had insufficient (&lt;30 ng/mL) and 52% had very low (&lt;15 ng/mL) levels of vitamin D. There was no correlation between age, duration of the disease, and body surface area affected with vitamin D levels. There was no significant difference in vitamin D levels between patients who had family history of vitiligo (5 patients, 20%) and those that did not.Vitamin D levels were found to be insufficient (&lt;30 ng/mL) or very low (&lt;15 ng/mL) in most of the patients with vitiligo vulgaris, but not statistically significantly different as a group when compared to the controls. More studies are needed to differentiate between the effects of low vitamin D levels on pathogenesis of vitiligo vulgaris and lower vitamin D levels as a result of the disease. </p

    Bis maltolato oxovanadium (BMOV) and ischemia/reperfusion-induced acute kidney injury in rats

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    The aim of the present study was to test the potential protective effects of the organic vanadium salt bis (maltolato) oxovanadium (BMOV; 15 mg/kg) in the context of renal ischemia/reperfusion (30 min of ischemia) and its effects on renal oxygenation and renal function in the acute phase of reperfusion (up to 90 min post-ischemia). Ischemia was established in anesthetized and mechanically ventilated male Wistar rats by renal artery clamping. Renal microvascular and venous oxygenation were measured using phosphorimetry. Creatinine clearance rate, sodium reabsorption, and renal oxygen handling efficiency were considered markers for renal function. The main findings were that BMOV did not affect the systemic and renal hemodynamic and oxygenation variables and partially protected renal sodium reabsorption. Pretreatment with the organic vanadium compound BMOV did not protect the kidney from I/R injur

    Single session endoscopic management of intrinsic ureteropelvic junction obstruction and concomitant renal stone disease in a child: a case report

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    BACKGROUND: Percutaneous nephrolithotomy is a well known therapeutic modality for stone diseases of childhood. Antegrade and retrograde endopyelotomies are also well defined options of treatment for secondary ureteropelvic junction obstruction. Yet there are few reports regarding endoscopic therapy of intrinsic ureteropelvic junction obstruction. To our knowledge, there exist only a few reports of endosurgical treatment of children with stone disease and with concomitant intrinsic ureteropelvic junction obstruction, in the literature. CASE PRESENTATION: We present the endoscopic management of stone disease and concomitant intrinsic ureteropelvic junction obstruction of a child in one session. CONCLUSION: Percutaneous nephrolithotomy and antegrade endopyelotomy is combined safely with successful outcome in a child

    Chronic hepatitis B associated with hepatic steatosis, insulin resistance, necroinflammation and fibrosis.

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    Background: The effect of hepatitis B virus (HBV) infection on fatty liver disease is unclear.. Objectives: The aim of this study was to investigate the viral and host causes of fatty liver in chronic hepatitis B (CHB) patients. This study included 88 CHB patients of which 17 were not treated. Liver biopsy was performed in each patient. Group 1 included those with hepatic steatosis (n=28) and group 2 those without hepatic steatosis. The groups were compared in terms of age, body mass index (BMI), Homeostasis Model Assessment- Insulin Resistance (HOMA-IR), viral load, biochemical parameters and histological findings. Patients in group 1 were subdivided according to the degree of steatosis as follows: grade 1 (15 patients, 53.6%), grade 2 (6 patients, 21.4%),and grade 3 (7 patients, 25%). Results: In group 1 (n=28), mean age, BMI, cholesterol, and HOMA-IR were found to be significantly higher than in group 2 (n=60). There were no significant differences in the positivity of viral load, HbeAg, treatment, fibrosis and other laboratory parameters between the two groups. HOMA-IR was the only independent predictive factor of liver steatosis in patients with CHB in logistic regression analysis. Conclusion: Hepatic steatosis in CHB patients was associated with host metabolic factors
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