Planetary nurseries: vortices formed at smooth viscosity transition

Excitation of Rossby wave instability and development of a large-scale vortex at the outer dead zone edge of protoplanetary discs is one of the leading theories that explains horseshoe-like brightness distribution in transition discs. Formation of such vortices requires a relatively sharp viscosity transition. Detailed modelling, however, indicates that viscosity transitions at the outer edge of the dead zone is relatively smooth. In this study, we present 2D global, non-isothermal, gas-dust coupled hydrodynamic simulations to investigate the possibility of vortex excitation at smooth viscosity transitions. Our models are based on a recently postulated scenario, wherein the recombination of charged particles on the surface of dust grains results in reduced ionisation fraction and in turn the turbulence due to magnetorotational instability. Thus, the alpha-parameter for the disc viscosity depends on the local dust-to-gas mass ratio. We found that the smooth viscosity transitions at the outer edge of the dead zone can become Rossby unstable and form vortices. A single large-scale vortex develops if the dust content of the disc is well coupled to the gas, however, multiple small-scale vortices ensue for the case of less coupled dust. As both type of vortices are trapped at the dead zone outer edge, they provide sufficient time for dust growth. The solid content collected by the vortices can exceed several hundred Earth masses, while the dust-to-gas density ratio within often exceeds unity. Thus, such vortices function as planetary nurseries within the disc, providing ideal sites for formation of planetesimals and eventually planetary systems.Comment: accepted for publication in MNRA

An Approach to Recommend Pages to User after Path Completion

With the huge amount of data available on the web, the effective and timely search is most important aspects. Because of tremendous USAge of web the size of the log files are becoming huge day by day. Web Mining which is an application of data mining can be used to improve web performance by generating patterns in the log files. Web Pre-fetching based on recommendation can be used to improve web performance. This paper proposes an architecture that recommends pages to the user based on studying the browsing activity of the user and other user of same USAge profile and completing it in every aspects and then recommending the pages which can be pre-fetched to improve web performance. This paper proposes about the path completion which shows users interest and then recommending pages to the user which will result in effective recommendation

A review on Charakokta Shukrajanana Mahakashaya

According to Ayurveda the Sharir (human body) is made of seven dhatus i.e rasa (fliud), rakta (blood), mamsa (muscles), meda (fat), asthi (bones), majja (marrow) and shukra (semen). Shukra dhatu is the 7th and the last dhatu made in the body. Hence, we can say shukra dhatu is sara (essence) of all the dhatus, it is well spreaded all through the body. The shukra dhatu according to modern concept can be understood as the sexual power, the ejaculation, the erectile strength, the quality of sperms, the semen or we can say overall reproductive strength of the person. The action of Shukra dhatu in the human body is regeneration of species. Any vitiation in the Shukra dhatu affects this action. Thus, hampering the progeny. Nowadays, due to lifestyle as well occupational hazards Shukra dhatu gets affected. Acharya Charaka has described “Shukrajanana mahakashaya” in the Sutrasthana 4th adhyaya. It is compilation of 10 drugs which helps in generation of Shukra dhatu and also helps in maintaining the product Shukra dhatu stage in the body. Many factors are involved in the generation of Shukra dhatu. Individual drugs out of 10 acts on various factors realated to Shukra dhatu. As per the causative factors, the Vaidya may adjust the dose of drugs of Shukrajanana mahakashaya and prescribe to the patient. In this article, identification and action of these drugs will be compiled and presented. On the basis of literature obtained, conclusion we be drawn

Исследование возможности проведения изотопного обмена в диоксиде углерода в каскаде газовых центрифуг

Проведено исследование применения реакций изотопного обмена при получении высокообогащенных изотопов углерода в каскаде газовых центрифуг, работающих на диоксиде углерода, и испытание опытного реактора изотопного обмена с никелевым катализатором. Показана принципиальная возможность применения реакций и реактора изотопного обмена для получения высокообогащенных изотопов углерода в каскаде газовых центрифуг