Statistical mechanics of confined quantum particles

We develop statistical mechanics and thermodynamics of Bose and Fermi systems in relativistic harmonic oscillator (RHO) confining potential, which may be applicable in quark gluon plasma (QGP), astrophysics, Bose-Einstein condensation (BEC), condensed matter physics etc. Detailed study of QGP system is carried out and compared with lattice results. Further, as an application, our equation of state (EoS) of QGP is used to study compact stars like quark star.Comment: 9 pages, 2 figures, articl

Pregnancy in breast cancer survivor with anthracycline induced cardiomyopathy

With earlier diagnosis and improved treatment modalities and management of breast cancer patients, survival is improving. An increasing number of survivors are in the reproductive age group; however a neglected medical area is contraceptive advice, failure of which can result in unwanted pregnancy and further medical complications. An undiagnosed pregnancy in a breast cancer survivor with known anthracycline- induced cardiomyopathy is presented here

Quasi-stationary sequences of hyper massive neutron stars with exotic equations of state

In this work, we study the effect of differential rotation, finite temperature and strangeness on the quasi stationary sequences of hyper massive neutron stars (HMNS). We generate constant rest mass sequences of differentially rotating and uniformly rotating stars. The nucleonic matter relevant to the star interior is described within the framework of the relativistic mean field model with the DD2 parameter set. We also consider the strange $\Lambda$ hyperons using the BHB$\Lambda\phi$ equation of state (EoS). Additionally, we probe the behaviour of neutron stars (NS) with these compositions at different temperatures. We report that the addition of hyperons to the EoS produces a significant boost to the spin-up phenomenon. Moreover, increasing the temperature can make the spin-up more robust. We also study the impact of strangeness and thermal effects on the T/W instability. Finally, we analyse equilibrium sequences of a NS following a stable transition from differential rotation to uniform rotation. The decrease in frequency relative to angular momentum loss during this transition is significantly smaller for EoS containing hyperons, compared to nucleonic EoS.Comment: Accepted for publication in the Journal of Astrophysics and Astronom

ROLE OF ANTIOXIDANTS AND NUTRITION IN OXIDATIVE STRESS: A REVIEW

Human body is known to experience positive stress that keeps it vigilant and protects it from biological and physical threats. This stress turns negative when a person is confronted with continuous challenges. Also, stress and nutrition have always run in synergism with each other. Nutritional value of a person's diet depends on the overall mixture or balance of food that is eaten over a period of time, as well as on the needs of the individual. The body relies on obtaining its anti-oxidants from food and other supplements. These nutritional requirements of antioxidants are enormously altered in diseased conditions. In view of the immense medicinal importance of antioxidants, an effort has been made in this article to bring together information about the role of nutrition and antioxidants such as carotenoids, vitamins, some important minerals in combating free radical generation and in general, boosting normal immune mechanisms. The present review is an attempt to generate interest in the scientific fraternity of their immense potential in preventing and treating several common diseases. Keywords: Antioxidants, Free radicals, Balanced diet, Nutrition, Oxidative stress, Vitamins

Power quality enhancement at distribution level utilizing the unified power quality conditioner (UPQC)

Power electronics based equipments are rapidly emerging as key components in the present modern power distribution system. Power processing utilizing these devices offer vast advantages such as flexible control, cost reduction, overall size optimization, etc. On the other hand, operation of these devices gives rise to some of the serious power quality problems, such as, the reactive power requirement and generation of harmonics that pollutes the power distribution system. Moreover, modern equipments are becoming highly sensitive to the voltage supplied to them. Increasing the generation capacities of existing power stations is difficult and expensive due to environmental constraints. Hence, improving the quality of power can not only make the power distribution systems healthier and more efficient, but also results in reduced power losses, and thus saving in terms of costs. Active power filters are widely used to tackle some of the important power quality problems. Recent trends are geared towards the realization of multitasking devices which can tackle several power quality problems simultaneously. The unified power quality conditioner (UPQC) is one of the most versatile active power filters that can compensate significant power quality issues, such as, voltage harmonics, voltage sag, voltage swell, voltage unbalance, voltage flicker, current harmonics, load reactive power, current unbalance, and neutral current. A UPQC consists of two voltage source inverters connected back to back with each other sharing a common self- supporting DC link. One inverter is controlled as a variable voltage source in same manner as in the series active power filter (APF), and the other as a variable current source which is similar in operation as that of the shunt APF. The existing literature suggests the dependency on shunt inverter to compensate the load reactive power demand. Moreover, the series inverter is always utilized to overcome all the voltage related problems. The voltage sags, swells and the flickers are short duration power quality problems. Hence, this traditional approach of utilizing the UPQC to compensate the power qualite problems shows a significant drawback of under usage of the available series inverter. Therefore, the utilization factor of the series inverter is much lower than that of the shunt inverter. The present doctoral work is based on the philosophy of optimal utilization of the available resources in a most effective and efficient way to improve the product efficiency and to reduce the overall cost. This work proposes a novel control concept, termed as power angle control (PAC), in which both the series and shunt inverters share the load reactive power in co-ordination with each other without affecting the basic UPQC compensation capabilities. This eventually results in a better utilization of the series inverter, reduction in the shunt inverter rating to some extent and ultimately in the reduction of the overall cost of UPQC. Moreover, this thesis also introduces a new functionality for UPQC in which, it is possible to extent the UPQC based three-phase three-wire system to a three-phase four-wire system. The developed PAC concept is successfully validated through digital simulation as well as extensive experimental investigations. The experimental results show that for the given laboratory test conditions with a highly inductive load, a boost in power angle 8=28° between the source and the resultant load voltage can reduce the shunt inverter rating by 50%. The performance evaluation of PAC approach under voltage sag, voltage swell, distorted source voltage and non-linear load conditions is also carried out. Under distorted source voltage (source voltage THD=6.6%) and the non-linear load (load current THD=23.4%), the UPQC with proposed PAC concept, effectively compensates the harmonics in source voltage (load voltage THD=3.2%), load current (source current THD= 2.94%) and shares the load reactive power between the series and shunt inverters, simultaneously. This work was partially conducted in collaboration with Hydro-Quebec, Montreal and Institut de recherche d'Hydro-Quebec (IREQ), Varennes, Canada

Treatment of the Intrinsic Hamiltonian in Particle-Number Nonconserving Theories

We discuss the implications of using an intrinsic Hamiltonian in theories without particle-number conservation, e.g., the Hartree-Fock-Bogoliubov approximation, where the Hamiltonian's particle-number dependence leads to discrepancies if one naively replaces the particle-number operator by its expectation value. We develop a systematic expansion that fixes this problem and leads to an a posteriori justification of the widely-used one- plus two-body form of the intrinsic kinetic energy in nuclear self-consistent field methods. The expansion's convergence properties as well as its practical applications are discussed for several sample nuclei.Comment: 6 pages, 5 figure

Comparison of conventional risk factors, clinical and angiographic profile between younger and older coronary heart disease patients

Background: Although numerous risk factors have been established to predict the development of Coronary artery Disease, the risk factor profile may be different between the younger and older individuals. The aim of the study was to compare risk factors, clinical profile and angiographic profile of young and old coronary heart disease patients.Methods: Patients admitted at cardiac intensive care unit at Sunderam Ahulraj Hospital of south India between January 2012 and December 2013 were classified in to two age groups with 40yrs as cut-off. Patients were assessed for conventional risk factors (diabetes mellitus, dyslipidaemia, hypertension, smoking, and obesity), clinical profile and angiographic profiles.Results: A total of 100 patients, out of which 32patients were ≤40yrs of age and 68 patients >40yrs of age, were evaluated. Mean age for younger group (40yrs) was 55.39 yrs. Range of age group for study population was 28-72 yrs. The prevalence of obesity, dyslipidaemia, and smoking/ tobacco chewing did not vary significantly between the two groups. Older patients had higher frequency of diabetes (48.5%) and hypertension (41.1%). The most commonly affected coronary artery was the left anterior descending artery among both age groups.Conclusions: Young patients with Coronary heart disease had different risk profile and less extensive coronary artery disease as compared to older counterparts. Emphasis should be given on diagnosis and management of major modifiable risk factors

The Triaxial Rotation Vibration Model in the Xe-Ba Region

The axial Rotation Vibration Model is here extended to describe also triaxial equilibrium shapes with beta and gamma vibrations allowing for the interaction between vibrations and rotations. This Triaxial Rotation Vibration Model (TRVM) is applied to Xe and Ba isotopes with mass numbers between 120 and 130. This area has recently been pointed out to be the O(6) limit of the Interacting Boson Approximation (IBA). The present work shows that the TRVM can equally well describe these nuclei concerning their excitation energies and E2 branching ratios.Comment: 11 pages, 2 figure

A Hierarchical Control Strategy With Fault Ride-Through Capability for Variable Frequency Transformer

A variable frequency transformer (VFT) is being considered as a new alternative to the classical back-to-back high voltage direct current (HVDC) link for interconnection of two asynchronous networks. The VFT is a retrospective form of frequency converter using the wound rotor induction machine (WRIM), which converts the constant frequency input into a variable frequency output. The prime objective of VFT is to achieve controlled bidirectional power transfer between the two asynchronous networks. This paper presents a detailed working principle of VFT technology and proposes a new hierarchical control strategy for establishing the VFT connection with two power systems to achieve bidirectional power transfer between them. Also, to restrict the grid fault propagation from one side of the VFT to the other side, a series dynamic braking resistor based fault ride-through (FRT) scheme is proposed. The performance of the VFT during the synchronization process, steady-state, dynamic, and the grid fault conditions is evaluated using the real-time hardware in-loop (HIL) system. The plant is simulated in real time using OPAL-RT real-time simulator while the control algorithm is implemented in digital signal processor to carry out HIL study. All the important results supporting the effectiveness of the proposed control strategy and FRT scheme are discussed

Rotational Bands and Electromagnetic Transitions of some even-even Neodymium Nuclei in J-Projected Hartree-Fock Model

Rotational structures of even-even $^{148-160}$Nd nuclei are studied with the self-consistent deformed Hartree-Fock (HF) and angular momentum (J) projection model. Spectra of ground band, recently observed $K=4^{-}$, $K=5^{-}$ and a few more excited, positive and negative parity bands have been studied upto high spin values. Apart from these detailed electromagnetic properties (like E2, M1 matrix elements) of all the bands have been obtained. There is substantial agreement between our model calculations and available experimental data. Predictions are made about the band structures and electromagnetic properties of these nuclei. Some 4-qasiparticle K-isomeric bands and their electromagnetic properties are predicted.Comment: 20 page