Transient thermal stresses due to axisymmetric heat supply in a semi-infinite thick circular plate

The present paper deals with the determination of thermal stresses in a semi-infinite thick circular plate of a finite length and infinite extent subjected to an axisymmetric heat supply. A thick circular plate is considered having constant initial temperature and arbitrary heat flux is applied on the upper and lower face. The governing heat conduction equation has been solved by using integral transform technique. The results are obtained in terms of Bessel’s function. The thermoelastic behavior has been computed numerically and illustrated graphically for a steel plate

Analysis of Maximum power Point Tracking in Solar Photovoltaic System

This paper presents a grid synchronization technique based on adaptive notch twist for SPV (Solar Photovoltaic) system along with MPPT (Maximum Power Point Tracking) techniques. An efficient grid synchronization technique offers capable detection of various components of grid signal like phase and frequency. It also acts as a obstruction for harmonics and other turbulence in grid signal. A reference phase signal synchronized with the grid voltage is provided by the grid synchronization technique to standardize the system with grid codes and power quality standards. Hence, grid synchronization unit plays important role for grid connected SPV systems. As the output of the PV array is variable in nature with the meteorological parameters like irradiance, temperature and wind etc. In order to maintain a constant DC voltage at VSC (Voltage Source Converter) input, MPPT control is required to track the maximum power point from PV array. In this work, a variable step size P & O (Perturb and Observe) MPPT technique with DC/DC boost converter has been used at first stage of the system

Great Inequality of Jupiter and Saturn I: The Planetary Three Body Problem, Heliocentric development by Lagrange multipliers, Perturbation Theory Formulation

In this paper, we undertake to present a self-contained and thorough analysis of the gravitational three body problem, with anticipated application to the Great Inequality of Jupiter and Saturn. The analysis of the three body Lagrangian is very convenient in heliocentric coordinates with Lagrange multipliers, the coordinates being the vector-sides $\vec{r}_i,\,i=1,2,3$ of the triangle that the bodies form. In two dimensions to begin with, the equations of motion are formulated into a dynamical system for the polar angles $\theta_i$, angular momenta $\ell_i$ and eccentricity vectors $\vec{e}_i$. The dynamical system is simplified considerably by change of variables to certain auxiliary vector $\vec{f}_i=\hat{r}_i+\vec{e}_i$. We then begin to formulate the Hamiltonian perturbation theory of the problem, now in three dimensions. We first give the geometric definitions for the Delaunay action-angle variables of the two body problem. We express the three body Hamiltonian in terms of Delaunay variables in each sector $i=1,2,3$, revealing that it is a nearly integrable Hamiltonian. We then present the KAM theory perturbative approach that will be followed in future work, including the modification that will be required because the Hamiltonian is degenerate

Study of rationality and utilization pattern of antimicrobials in ear, nose, throat outpatient department of Tertiary Care Hospital, Nanded

Background: Antimicrobials are most commonly prescribed drugs worldwide. Around 50% of the prescriptions of antimicrobial drugs are either not needed, inappropriate or in wrong doses. With the widespread use of antimicrobial agents (AMAs), the prevalence of resistance has increased. To evaluate the prescription pattern and utilization of AMA in ear, nose, throat (ENT) outpatient department (OPD) of Tertiary Care Hospital, Nanded.Methods: This prospective study was conducted in ENT OPD of Dr. Shankarrao Chavan Government Medical College, Nanded over a period of 3 months. During this period, approximately 1100 patients visited ENT OPD and 600 prescriptions were evaluated. The excluded patients were of post-operative follow-up and of patients undergoing medical examination for fitness and handicap certificate. Data were collected by using specially designed case report form. Appropriateness of AMA was assessed by Kunin’s modified criteria.Results: Total 600 prescriptions were analyzed out of which (91%) consist of AMA. Most of them reported with upper respiratory tract infections (URTI) (30.4%), chronic suppurative otitis media (21.4%), acute suppurative otitis media (10.4%), tonsillitis (3.3%), sinusitis (2.7%), and others (15%). Amoxicillin (43.9%) was preferred AMA followed by ciprofloxacin (30.6%), cotrimoxazole (5.8%), azithromycin (3.2%), doxycycline (3.2%) cefixime + clavulanate (3.2%), and amoxicillin + clavulanate (1.8%). Single antibiotic was preferred in all prescriptions. In the concomitant medications, antihistaminics were prescribed in 97.22% of patients, non-steroidal anti-inflammatory drugs in 94.96% of patients, and antacids in 87.76% of patients. Fixed-dose combinations were used in 10% of prescriptions. Brand names of AMA were used in 10% of prescriptions. As per the Kunin’s modified criteria, 83% of patients received AMA therapy appropriately, while 17% patients inappropriately.Conclusions: Amoxicillin is the most common AMA prescribed and URTI is the most common diagnosis made. All AMAs should be prescribed only when needed and should be used in proper dose and for proper duration. Institution wise antibiotic policy should be used to contain resistance. Proper training and regular orientation programs of the juniors’ doctors for judicial use of AMAs will foster the habit of rational prescribing of AMA

Giant angioleiomyoma of uterus masquerading as ovarian tumour: a case report

Angioleiomyoma is a rare benign tumour of uterus. We are presenting an unusual case of 45-year-old female with 11 kg giant angioleiomyoma of uterus which was masquerading as ovarian tumour on imaging. Exploratory laparotomy was done which was suggestive of huge lobulated mass arising from the uterus. Hysterectomy with bilateral salpingo-oophorectomy was done. Histopathological examination of specimen was suggestive of uterine subserosal and broad ligament angioleiomyoma of cavernous type. This case is being reported because of its rarity and challenges in diagnosis and management

Inverse Heat Conduction Problem in a Semi-Infinite Circular Plate and its Thermal Deflection by Quasi-Static Approach

This paper concerns the inverse heat conduction problem in a semi-infinite thin circular plate subjected to an arbitrary known temperature under unsteady condition and the behavior of thermal deflection has been discussed on the outer curved surface with the help of mathematical modeling. The solutions are obtained in an analytical form by using the integral transform technique

Thermal stresses in functionally graded hollow sphere due to non-uniform internal heat generation

In this article, the thermal stresses in a hollow thick sphere of functionally graded material subjected to non-uniform internal heat generation are obtained as a function of radius to an exact solution by using the theory of elasticity. Material properties and heat generation are assumed as a function of radius of sphere and Poisson’s ratio as constant. The distribution of thermal stresses for different values of the powers of the module of elasticity and varying power law index of heat generation is studied. The results are illustrated numerically and graphically

Thermal stresses in an infinite body with spherical cavity due to an arbitrary heat flux on its internal boundary surface

In this paper we consider an elastic infinite body with a spherical cavity subjected to a arbitrary heat flux on its internal boundary which is assumed to be traction free. The displacement and thermal stresses are obtained and results are compared using constant and time dependent heat flux. Laplace transform technique is used to obtain the temperature distribution. The mathematical model is obtained for copper material. The results are illustrated numerically and graphically