Development of a self balanced robot and its controller

Two wheeled balancing robots are based on inverted pendulum configuration which relies upon dynamic balancing systems for balancing and maneuvering. This project is based on the development of a self-balanced two wheeled robot which has a configuration similar to a bicycle. These robot bases provide exceptional robustness and capability due to their smaller size and power requirements. Outcome of research in this field had led to the birth of robots such as Segway, Murata boy etc. Such robots find their applications in surveillance & transportation purpose. Here, in particular, the focus is on the electro-mechanical mechanisms & control algorithms required to enable the robot to perceive and act in real time for a dynamically changing world. Using an Ultrasonic sensor and an accelerometer we get the information about the tilt of the robot from its equilibrium position. Balancing was done using a servo motor, a DC motor and a control momnt gyroscope. While these techniques are applicable to many robot applications, the construction of sensors, filters and actuator system is a learning experience

Effect of Site-disorder, Off-stoichiometry and Epitaxial Strain on the Optical Properties of Magnetoelectric Gallium Ferrite

We present a combined experimental-theoretical study demonstrating the role of site disorder, off-stoichiometry and strain on the optical behavior of magnetoelectric gallium ferrite. Optical properties such as band-gap, refractive indices and dielectric constants were experimentally obtained by performing ellipsometric studies over the energy range 0.8 eV to 4.2 eV on pulsed laser deposited epitaxial thin films of stoichiometric gallium ferrite with b-axis orientation and the data was compared with theoretical results. Calculations on the ground state structure show that the optical activity in GaFeO3 arises primarily from O2p-Fe3d transitions. Further, inclusion of site disorder and epitaxial strain in the ground state structure significantly improves the agreement between the theory and the room temperature experimental data substantiating the presence of site-disorder in the experimentally derived strained GaFeO3 films at room temperature. We attribute the modification of the ground state optical behavior upon inclusion of site disorder to the corresponding changes in the electronic band structure, especially in Fe3d states leading to a lowered band-gap of the material.Comment: 18 Pages, 6 figure

Chronic pelvic pain in women: comparative study between ultrasonography and laparoscopy as diagnostic tool

Background: Chronic pelvic pain is a major cause of morbidity among the reproductive age group women. The study on patients of chronic pelvic pain aimed to compare the diagnostic accuracy of ultrasonography and laparoscopy in these patientsMethods: The study was conducted on 100 patients of chronic pelvic pain attending the gynaecology outdoor and were subjected to thorough clinical examination followed by ultrasonography and laparoscopic examination.Results: Maximum number of cases of chronic pelvic pain belonged to 25-30 years, were parous with mean duration of pain of 15.2 months. The most common complaint was vaginal discharge (70%) followed by menstrual irregularity. On clinical examination, pelvic tenderness was observed in majority (60%) of cases. USG examination showed chronic pelvic inflammatory disease in 43% cases followed by myoma (8%), ovarian cyst (5%), endometriosis (6%), pelvic congestion (5%) and no abnormal pathology in 25% cases. On laparoscopic examination, chronic pelvic inflammatory disease was present in 47% cases followed by endometriosis (11%), pelvic congestion (8%), myoma (8%), adhesions (7%) while 13% cases showed normal findings.Conclusions: Laparoscopy is more effective than ultrasonography as a diagnostic tool in patients of chronic pelvic pain.

Electronic Structures, Born Effective Charges and Spontaneous Polarization in Magnetoelectric Gallium Ferrite

We present a theoretical study of the structure-property correlation in gallium ferrite, based on the first principles calculations followed by a subsequent comparison with the experiments. Local spin density approximation (LSDA+U) of the density functional theory has been used to calculate the ground state structure, electronic band structure, density of states and Born effective charges. Calculations reveal that the ground state structure is orthorhombic Pc21n having A-type antiferromagnetic spin configuration, with lattice parameters matching well with those obtained experimentally. Plots of partial density of states of constituent ions exhibit noticeable hybridization of Fe 3d, Ga 4s, Ga 4p and O 2p states. However, the calculated charge density and electron localization function show largely ionic character of the Ga/Fe-O bonds which is also supported by lack of any significant anomaly in the calculated Born effective charges with respect to the corresponding nominal ionic charges. The calculations show a spontaneous polarization of ~ 59 microC/cm^2 along b-axis which is largely due to asymmetrically placed Ga1, Fe1, O1, O2 and O6 ions.Comment: Total 21 pages including 3 tables and 6 figure

First-Principles Calculation of Born Effective Charges and Spontaneous Polarization of Ferroelectric Bismuth Titanate

In this study, we present the results of our first-principles calculations of the band structure, density of states and the Born effective charge tensors for the ferroelectric (ground state B1a1) and paraelectric (I4/mmm) phases of bismuth titanate. The calculations are done using the generalized gradient approximation (GGA) as well as the local density approximation (LDA) of the density functional theory. In contrast to the literature, our calculations on B1a1 structure using GGA and LDA yield smaller indirect band gaps as compared to the direct band gaps, in agreement with the experimental data. The density of states shows considerable hybridization among Ti 3d, Bi 6p and O 2p states indicating covalent nature of the bonds leading to the ferroelectric instability. The Born effective charge tensors of the constituent ions for the ground state (B1a1) and paraelectric (I4/mmm) structures were calculated using the Berry phase method. This is followed by the calculation of the spontaneous polarization for the ferroelectric B1a1 phase using the Born effective charge tensors of the individual ions. The calculated value for the spontaneous polarization of ferroelectric bismuth titanate using different Born effective charges was found to be in the range of 55+/-13 $\mu$C/cm2 in comparison to the reported experimental value of (50+/-10 $\mu$C/cm2) for single crystals. The origin of ferroelectricity is attributed to the relatively large displacements of those oxygen ions in the TiO6 octahedra that lie along the a-axis of the bismuth titanate crystal.Comment: 36 pages, 5 figure

Hashimoto Encephalopathy in Case of Progressive Cognitive Impairment; a Case Report

Hashimoto's encephalopathy (HE) is a rare condition characterized by atypical psychiatric and heterogeneous neurological manifestations such as acute cerebral ischemia, seizure, tremors, myoclonus, psychosis, depression, cognitive disorders, and fluctuating loss of consciousness. Here, a case of 28 year-old man was reported who referred to the emergency department (ED) with different acute neurologic disorders and final diagnose of HE

Non hodgkin’s lymphoma misdiagnosed as tuberculosis: A case report

Non-Hodgkin’s Lymphoma is a heterogeneous group of malignancies characterized by an abnormal clonal proliferation of T-cells, B-cells or both. Sometimes, tuberculosis and lymphoma presentation can share common symptoms and features. A 37-year-old male patient was admitted in the hospital with complains of shortness of breath associated with cough, loss of appetite, generalized weakness and weight loss since two months. There were no palpable peripheral lymph nodes present anywhere in the body. The patient had no personal or family history of tuberculosis. The chest X-ray showed bilateral mild pleural effusion with confluent radio opacities in both lung fields. Pleural fluid biochemistry showed increased Adenosine deaminase level with increased protein and low sugar. Antitubercular drugs were started after initial diagnosis of tuberculosis. After non improvement in symptoms fine needleaspiration cytology (FNAC) was done from spleen which showed finding suggestive of non- hodgkins lymphoma

Efficacy of topical phenytoin in healing diabetic foot ulcer

Background: India is fast becoming world diabetes capital. Complications are a cause of hospitalization in patients with diabetes mellitus especially foot complications. Gauze moistened with saline has been the standard method.Methods: The study was done from June 2015 to June 2016. The objective of this study was to assess the efficacy of topical phenytoin compared to standard and conventional methods of wound care in improving the healing process. In this randomised control trial, the data from 70 patients with diabetic ulcers was collected, 35 patients underwent topical phenytoin dressing while remaining 35 underwent conventional wound care. Histopathological and Clinical examination were done and the following parameters were calculated: Granulation tissue formation in 2 weeks and Mean duration of hospital stay.Results: In this study, Mean hospital stay in days was 33.4 in Phenytoin treated group and in other group with use conventional materials, the mean hospital stay in days was 39.7 days. Granulation tissue formation was faster as compared to conventional materials of Dressings.Conclusions: In this study we conclude Topical phenytoin helps in faster healing of Diabetic Foot Ulcers and it also reduces the mean hospital stay of the patients

Optical Anisotropy in Bismuth Titanate: An Experimental and Theoretical Study

We report experimental and theoretical investigation of anisotropy in optical properties and their origin in the ferroelectric and paraelectric phases of bismuth titanate. Room temperature ellipsometric measurements performed on pulsed laser deposited bismuth titanate thin films of different orientations show anisotropy in the dielectric and optical constants, Subsequent first-principles calculations performed on the ground state structures of ferroelectric and high temperature paraelectric phases of bismuth titanate show that the material demonstrates anisotropic optical behavior in both ferroelectric and paraelectric phases. We further show that O 2p to Ti 3d transition is the primary origin of optical activity of the material while optical anisotropy results from the asymmetrically oriented Ti-O bonds in TiO6 octehdra in the unit cell.Comment: 13 pages, 4 figure