STUDYING THE EFFECTS OF INITIAL CRACK ANGLE ON THE CRACK PROPAGATION IN GRAPHENE NANO-RIBBON THROUGH MOLECULAR DYNAMICS SIMULATIONS

In this research, we have worked on the brittle fracture of graphene nano-ribbon to explore the behavior of crack propagation at different crack angles. We have performed classical Molecular Dynamics simulations using LAMMPS at ten different crack angles between 0 degrees and 45 degrees, in an increment of 5 degrees to observe the parameters that dominate the crack path. The graphene nanoribbon is loaded in the zigzag direction by pulling it in the armchair direction with a pre-existing crack in the center. We have used OVITO for the visualization of the simulation. AIREBO potential is employed in this work because it is extensively used in the fracture of graphene with different loading conditions and temperatures. The crack path is determined for all ten nanoribbons and the nanoribbon with a crack at 25° turned out to be the weakest because of the sharp crack tip and crack shape. The results are validated with the published results and are in accordance with them

Competition between antiferromagnetism and superconductivity, electron-hole doping asymmetry and "Fermi Surface" topology in cuprates

We investigate the asymmetry between electron and hole doping in a 2D Mott insulator, and the resulting competition between antiferromagnetism (AF) and d-wave superconductivity (SC), using variational Monte Carlo for projected wave functions. We find that key features of the T = 0 phase diagram, such as critical doping for SC-AF coexistence and the maximum value of the SC order parameter, are determined by a single parameter which characterises the topology of the "Fermi surface" at half filling defined by the bare tight-binding parameters. Our results give insight into why AF wins for electron doping, while SC is dominant on the hole doped side. We also suggest using band structure engineering to control the parameter for enhancing SC.Comment: 4 pages, 4 figure

SPECIFIC ABSORPTION RATE (SAR) DUE TO VARIATION IN FREQUENCY ON HUMAN BODY TISSUES NEAR RADIO BROADCASTING ANTENNA

 Objective: Theoretical studies are made for the specific absorption rate (SAR) in consequences of induced electric fields due to radio broadcastingtower at 100 m distance.Methods: The penetrated electric fields and SAR inside human body tissues are calculated for different frequencies. A comparison is made with theinternational safety guidelines given by World Health Organization and International Commission on Non-ionizing Radiation Protection.Results: The penetrated electric field and SAR by some tissues at frequencies 1377, 1404, 1485, 1512, and 1530 kHz of electromagnetic waves arecomputed.Conclusion: According to permissible limit the frequencies 1377, 1404, 1485, 1512 and 1530 kHz of 20 kW EM radiations at 100 m distance are safefor tissues bladder, blood vessel, brain white matter, fat, heart, lung outer and mucous membrane at depths 0.1, 0.2 and 0.3 mm respectively. And thisradiation is harmful for blood, body fluid, cerebella spinal fluid, eye sclera, gall bladder, gall bladder bile, gland, lung inner, lymph, mucous membrane,pancreas, stomach, testis and vitreous humor tissues at depths 0.1, 0.2 and 0.3 mm, respectively.Keywords: Induced electric field, Specific absorption rate, Thermoregulatory mechanism and broadcasting antenna.Â

Possibility of High Tc Superconductivity in doped Graphene

Graphene is at the forefront of condensed matter sciences, because of a variety of interesting phenomena it supports. If graphene could support high Tc superconductivity, after doping for example, it will make it even more valuable. Some authors have suggested possibility of superconductivity in graphite like systems. However, an early suggestion of one of us (Baskaran) was unique in the sense it combined Pauling's classic idea of resonating valence bond physics with band theory to obtain some exciting results for superconductivity. Black-Schaffer and Doniach took this approach further and found an unconventional d + id order parameter. To sharpen our theory and get more convincing and reliable results for superconductivity, we introduce a correlated variational BCS ground state wavefunction and perform extensive Monte Carlo study of the repulsive Hubbard model on the honeycomb lattice. We find that undoped graphene is not a superconductor, consistent with experiments and also mean field results. Interestingly, an appreciable superconducting order is obtained around an optimal doping. This result and a supportive slave particle analysis together suggest the possibility of high temperature superconductivity in doped graphene.Comment: 6 Pages, 3 Figure

Superior vena cava syndrome due to pacemaker leads: an Indian report with a review of management practices

Superior vena cava [SVC] syndrome due to pacemaker leads is a distinct diagnostic rarity. It is diagnosed clinically based on constellation of signs and symptoms supported by imaging evidence of SVC obstruction. A 70-year-old male, an ex-smoker, presented with facial and upper limb swelling along with exertional dyspnea. He had undergone transvenous dual chamber rate modulated [DDDR] pacemaker implantation four years back for symptomatic sinus node dysfunction. Imaging demonstrated a hypodense-filling defect in the SVC causing 70-80% luminal narrowing along with presence of collaterals. Patient was managed on anticoagulants and planned for SVC stenting with epicardial pacing which failed. Patient refused to undergo further any further treatment and was subsequently lost to follow-up. To the best of our knowledge, this is the first detailed description of SVC syndrome due to pacemaker leads from India, which was managed medically

Methods of obtaining smooth surface in 2D/3D surface reconstruction

Surface reconstruction is an emergent research area in the field of computer aided design and manufacturing. There are various methods / algorithms which are working considerably well for surface reconstruction problem but we cannot say to the best of our knowledge that we got all the solutions. Missing surface can be repaired either by surface patch or by extending boundary curves. However, in both cases, surface smoothening problem arises in form of flat surface. The present paper has been tried to offer a solution to above problem which makes the curve smoother

Innovative approaches in Mexico and North East India health care system and their implications in other Ibero American countries

Objetives - Discuss and look at innovative ideas in Mexico and North east India to structure a better healthcare system for other Ibero American countries. - Overcome shortage of human resources for health and provide center for information systems in North east India and its implications. - Execute a more refined system in healthcare education.Trabajos libres ISTEC Salud y ACE.Ibero-American Science and Technology Education Consortium (ISTEC