Bulk viscosity in hyperonic star and r-mode instability

We consider a rotating neutron star with the presence of hyperons in its core, using an equation of state in an effective chiral model within the relativistic mean field approximation. We calculate the hyperonic bulk viscosity coefficient due to nonleptonic weak interactions. By estimating the damping timescales of the dissipative processes, we investigate its role in the suppression of gravitationally driven instabilities in the $r$-mode. We observe that $r$-mode instability remains very much significant for hyperon core temperature of around $10^8$K, resulting in a comparatively larger instability window. We find that such instability can reduce the angular velocity of the rapidly rotating star considerably upto $\sim0.04 \Omega_K$, with $\Omega_K$ as the Keplerian angular velocity.Comment: 10 pages including 7 figure

Spatial heterogeneities in the mass concentration of near surface aerosols over the Arabian Sea during ICARB

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Hyperon bulk viscosity and rr-modes of neutron stars

We propose and apply a new parameterization of the modified chiral effective model to study rotating neutron stars with hyperon cores in the framework of the relativistic mean-field theory. The inclusion of mesonic cross couplings in the model has improved the density content of the symmetry energy slope parameters, which are in agreement with the findings from recent terrestrial experiments. The bulk viscosity of the hyperonic medium is analyzed to investigate its role in the suppression of gravitationally driven $r$-modes. The hyperonic bulk viscosity coefficient caused by non-leptonic weak interactions and the corresponding damping timescales are calculated and the $r$-mode instability windows are obtained. The present model predicts a significant reduction of the unstable region due to a more effective damping of oscillations. We find that from $\sim 10^8$ K to $\sim 10^{9}$ K, hyperonic bulk viscosity completely suppresses the $r$-modes leading to a stable region between the instability windows. Our analysis indicates that the instability can reduce the angular velocity of the star up to $\sim$0.3~$\Omega_K$, where $\Omega_K$ is the Kepler frequency of the star.Comment: 9 pages, 9 figures; Accepted for publication in MNRA

On attributes of a Rotating Neutron star with a Hyperon core

We study the effect of rotation on global properties of neutron star with a hyperon core in an effective chiral model with varying nucleon effective mass within a mean field approach. The resulting gross properties of the rotating compact star sequences are then compared and analyzed with other theoretical predictions and observations from neutron stars. The maximum mass of the compact star predicted by the model lies in the range $(1.4-2.4) ~M_{\odot}$ at Kepler frequency $\Omega_K$, which is consistant with recent observation of high mass stars thereby reflecting the sensitivity of the underlying nucleon effective mass in the dense matter EoS. We also discuss the implications of the experimental constraints from the flow data from heavy-ion collisions on the global properties of the rotating neutron stars.Comment: 11 Pages, 10 Figures and 2 Table

Bioremediation Of Dairy Wastewater Using Microalgae For The Production Of Biodiesel

This study describes the feasibility for treatment of dairy waste waters in batch cultures by using selected strains of green microalgae namely Chlorella vulgaris, Botryococcus braunii and a mixed algal culture in indoor and outdoor. The Biomass productivity peaked on the 6th day. Best results were observed in C. vulgaris strain in both indoor and outdoor studies with biomass productivity of 0.51g/L, chlorophyll concentration of 0.039mg/L and lipid yield of 0.030g/L in indoor cultures whereas 0.59g/L of biomass productivity, 0.045mg/L chlorophyll concentration and 0.035g/L lipid yields were obtained in outdoor studies.. Gas Chromatography mass Spectrophotometer (GC MS) analysis of the extracted lipids showed that major components in C.vulgaris and mixed algae were palmitic acid, staeric acid and oleic acid where as oleic acid was the major component in B.braunii and palmitic acid, staeric acid were also present in minor amounts

Enabling hypervisor environment for increasing efficiency and effectiveness of training programmes - a case study at NAARM

The National Academy of Agricultural Research Management (NAARM) was established by the Indian Council of Agricultural Research (ICAR) at Hyderabad, in 1976, to address issues related to agricultural research and education management. The Academy also renders services for building IP portfolios like patents and geographical indications to various stakeholders including farmers and scientists. Keeping in view the increasing national and global need to integrate agriculture with agribusiness for raising rural incomes, and the increased emphasis on the creation, dissemination, application and exchange of knowledge in this vital area, the Academy has recently initiated post graduate education programmes and set up an Agribusiness Knowledge Centre. In the above mentioned scenario, NAARM also conducting many training programmes/courses over the year and there is lot of time and money being invested into purchasing physical machines and software. There is a need of maintaining specific set of software required for each training. The Coordinators of the training programmes has to ensure beforehand that all the machines are working fine and all the software required for that training got installed in all machines and working without any issues. This requirement of preparedness for training programmes has been avoided completely by establishing a private cloud which can provide Infrastructure as a Service (IaaS) at our organization. At the end of programmes may it be a regular or refresher course, coordinators has supposed to be evaluate the participants by tools like quizzes and exams. NAARM is using SynchronEyes Student-Teacher software for evaluation purpose. Many issues were there in this examinations system because of network, virus and power problems. This also has been completely avoided by establishing a hybrid cloud

Convective thundercloud development over the western ghats mountain slope in Kerala

Studies were carried out on the data from Braemore mountain observatory (lat. 8°45'N, long. 77°5'E) using a single-lens ceilometer (LIDAR), an electric field mill and a portable automatic weather station throughout the year 2010. The simultaneous data collected using the above instruments indicate the existence of strong updrafts followed by the formation of thunderclouds, a characteristic of the mountain slopes, during the thunderstorm months. Changes in atmosphere related to condensation and formation of water droplets during updraft events on the mountain slope could be detected from the ceilometer scattering data. Results of the study point to the cause of relatively more thunderstorm activity in that zone. This seems to be due to excessive updraft, which is strongly related to lightning activity in the region