Constrained Discrete Phase Control of a Heaving Wave Energy Converter in Irregular Seas Using Reinforcement Learning

Designed for offshore deployment in irregular seas, the point absorber wave energy conversion (WEC) system is promisingly attractive amongst the currently available WEC technologies. The effectiveness of phase control when applied to a heaving point absorber through a hydraulic power take-off (PTO) system is systematically investigated in both regular and irregular waves. For this purpose, two phase control accumulators are utilized in the hydraulic PTO system. Simulations are performed in MATLAB® using the Cummins equation to model the dynamics of the heaving point absorber in the time domain. For a given sea state, the opening instant of the control valves of the phase control accumulators relative to the wave excitation peak and the volumetric displacement of the hydraulic motor are utilized as parameters in a number of simulation runs. In regular waves, the parametric investigation demonstrates that in most cases there is a trade off between maximizing the mean generated power and minimizing the maximum motion amplitude. In fully developed irregular seas, a parametric investigation of different sea states in the North Atlantic demonstrates that by utilizing phase control a significant increase in the power absorption efficiency can be obtained compared to the WEC system operation without phase control. The problem of providing an effective phase-control strategy that maximizes the mean generated power of the WEC system subject to motion amplitude constraints is formulated and solved using a Reinforcement Learning (RL) approach based on the Q-learning algorithm. The RL-based controller chooses actions that determine the opening instant of the phase control accumulator valves and the volumetric displacement of the hydraulic motor. As demonstrated in both regular and irregular waves, the RL-based controller is successful in finding the optimal phase-control strategy. Finally, the prediction of the wave excitation force is performed using a Radial Basis Function (RBF) network ensemble in order to evaluate the impact of the prediction accuracy on the RL-controller\u27s performance. The results show that the computed mean generated power and maximum motion amplitude values using the RBF network ensemble predictions compare very well with the corresponding values computed assuming perfect knowledge of the future wave excitation

Long term Ultra-Violet Variability of Seyfert galaxies

Flux variability is one of the defining characteristics of Seyfert galaxies, a class of active galactic nuclei (AGN). Though these variations are observed over a wide range of wavelengths, results on their flux variability characteristics in the ultra-violet (UV) band are very limited. We present here the long term UV flux variability characteristics of a sample of fourteen Seyfert galaxies using data from the International Ultraviolet Explorer acquired between 1978 and 1995. We found that all the sources showed flux variations with no statistically significant difference in the amplitude of UV flux variation between shorter and longer wavelengths. Also, the flux variations between different near-UV (NUV, 1850 - 3300 A) and far-UV (FUV, 1150 - 2000 A) passbands in the rest frames of the objects are correlated with no time lag. The data show indications of (i) a mild negative correlation of UV variability with bolometric luminosity and (ii) weak positive correlation between UV variability and black hole mass. At FUV, about 50% of the sources show a strong correlation between spectral indices and flux variations with a hardening when brightening behaviour, while for the remaining sources the correlation is moderate. In NUV, the sources do show a harder when brighter trend, however, the correlation is either weak or moderate.Comment: Accepted by Journal of Astrophysics and Astronom

Bacteriological profile and antibiotic sensitivity pattern of blood culture isolates from tertiary care level teaching hospital of Vijayapura district

Background: Blood stream infections, ranging from self-limiting bacteraemia to life threatening septicaemia, remain one of the most important cause of morbidity and mortality worldwide. Sepsis is a systemic illness caused by microbial invasion of normally sterile parts of the body. Bacteria isolated from blood stream infections are numerous and diseases related to them need urgent treatment with antimicrobial drugs. Aim was to study the bacteriological profile of positive blood cultures and to find their antibiotic sensitivity patternMethods: A retrospective analysis of positive blood culture reports was done in the microbiology laboratory of present tertiary care teaching hospital (Al-Ameen Medical College, Vijayapura) for the consecutive year 2017, 2018 and 2019.Results: Total 21% samples found positive on blood culture shows Staphylococcus aureus as most common organism followed by Klebseilla and E.Coli antibiotic sensitivity pattern shows maximum sensitive to gentamicin (92%) and vancomycin (92%) as maximum resistance to penicillin (55%). Gram-positive organisms show more resistance to penicillin and least to vancomycin whereas gram-negative organisms show more resistance to cephalosporin group of antibiotics and least resistance to ciprofloxacin/gentamicin.Conclusions: Resistance pattern of organisms to some commonly used drugs has given warning signal to clinicians to search for alternate effective antibiotics and hospital authorities to formulate antibiotic policy for rationale use of antibiotics to prevent drug resistance

Finding Universal Relations using Statistical Data Analysis

We present applications of statistical data analysis methods from both bi- and multivariate statistics to find suitable sets of neutron star features that can be leveraged for accurate and EoS independent -- or universal -- relations. To this end, we investigate the ability of various correlation measures such as Distance Correlation and Mutual Information in identifying universally related pairs of neutron star features. We also evaluate relations produced by methods of multivariate statistics such as Principal Component Analysis to assess their suitability for producing universal relations with multiple independent variables. As part of our analyses, we also put forward multiple entirely novel relations, including multivariate relations for the $f$-mode frequency of neutron stars with reduced error when compared to existing, bivariate relations.Comment: 19 pages, 29 figures, 6 table

The Theme of Friendship in Kambar’s Select Occasional Verses: A Critical Analysis

In our everyday life, we come across many relationships. One of the most unique relationships is friendship which we encounter with different people in different situations of our lives. This paper discusses the friendship experienced by Kambar which he has expressed through his occasional verses. Friendship has been classified into five kinds based on the experiences of Kambar culled out from his occasional verses. The five kinds of friendship are (i) friendship based on gratitude, (ii) friendship based on caste to which he belongs, (iii) friendship based on his scholarliness, (iv)Friendship based on profit and (v) friendship based on love

A PROSPECTIVE STUDY ON ROLE OF VITAMIN E SUPPLEMENTATION IN TYPE 2 DIABETES MELLITUS

Aim and Objective: The aim of the study was to evaluate the role of Vitamin E supplementation in Type II diabetes mellitus (DM), to determines whether people with Type II DM treated with hypoglycemic agents alone, with or without Vitamin E, to determines the drug interaction in such treatment regimen, and to evaluates the Safety of the regimen.Methods: Type II DM patients with or without complications were included in this study along with serum glycated hemoglobin (HbA1c) concentration between 7.5% and 9.5%. They are divided into test group (which received hypoglycemic agent along with Vitamin E 4000 IU) and control group. Body mass index (BMI) status, fasting blood sugar (FBS), and post-prandial blood sugar (PPBS) were noted once in a month, HbA1c percentage, total cholesterol level (TC), and serum Vitamin E level were estimated and noted for every 3 months at total 9 months of this study. Patients with other comorbid conditions were prominent in this study.Results: It is perceptible with the analysis of obtained data that FBS, PPBS, HbA1c percentage, TC level, and BMI status of the patients were declined gradually in test group (patients with Vitamin E supplementation along with their hypoglycemic agents). Thus, antioxidant therapy is highly propitious whereby delaying the onset of complications in patients with DM. This development would be highly helpful for diabetic patients

Enhanced ionic conductivity in nano-composite solid polymer electrolyte: (PEG)x LiBr: y(SiO2)

In this paper, we report an enhancement in ionic conductivity in a new nano-composite solid polymer electrolyte namely, (PEG)x LiBr: y(SiO2). The samples were prepared, characterized, and investigated by XRD, IR, NMR, and impedance spectroscopy. Conductivity as a function of salt concentration shows a double peak. Five weight percent addition of silica nanoparticles increases the ionic conductivity by two orders of magnitude. Conductivity exhibits an Arrhenius type dependence on temperature. IR study has shown that the existence of nanoparticles in the vicinity of terminal O―H group results in a shift in IR absorption frequency and increase in amplitude of vibration of the terminal O―H group. This might lead to an enhancement in conductivity due to increased segmental motion of the polymer. 7Li NMR spectroscopic studies also seem to support this. Thus addition of nanoparticle inert fillers still seems to be a promising technique to enhance the ionic conductivity in solid polymer electrolytes

A STUDY ON PATIENTS AWARENESS ON RATIONAL USE OF ANTIBIOTICS AND ITS RESISTANCE

Objectives: Antibiotics are needed for many serious illnesses such as bacterial pneumonia, bacterial meningitis, septicemia, and even strep throat.These illnesses can be life threatening or can lead to serious complications. The work aims to create an awareness on antibiotics and its resistance inpatients. The main objective of this work is to study the patient knowledge through knowledge assessment questionnaire, to promote the rational useof antibiotics and to educate the patients using antibiotics.Methods: A questionnaire was prepared and data were collected from the patients based on which the study was carried out.Results and Conclusion: A very high consumption of antibiotics was observed.there was a higher use of cephalosporins. Dispensing of antibioticsis very high in community pharmacy despite of federal regulations, heath education programs should be taken to the patients regarding antibiotics.Keywords: Rational use, Antibiotics, Resistance