2,342 research outputs found
Modelling ripples in Orion with coupled dust dynamics and radiative transfer
In light of the recent detection of direct evidence for the formation of
Kelvin-Helmholtz instabilities in the Orion nebula, we expand upon previous
modelling efforts by numerically simulating the shear-flow driven gas and dust
dynamics in locations where the H region and the molecular cloud
interact. We aim to directly confront the simulation results with the infrared
observations. Methods: To numerically model the onset and full nonlinear
development of the Kelvin-Helmholtz instability we take the setup proposed to
interpret the observations, and adjust it to a full 3D hydrodynamical
simulation that includes the dynamics of gas as well as dust. A dust grain
distribution with sizes between 5-250 nm is used, exploiting the gas+dust
module of the MPI-AMRVAC code, in which the dust species are represented by
several pressureless dust fluids. The evolution of the model is followed well
into the nonlinear phase. The output of these simulations is then used as input
for the SKIRT dust radiative transfer code to obtain infrared images at several
stages of the evolution, which can be compared to the observations. Results: We
confirm that a 3D Kelvin-Helmholtz instability is able to develop in the
proposed setup, and that the formation of the instability is not inhibited by
the addition of dust. Kelvin-Helmholtz billows form at the end of the linear
phase, and synthetic observations of the billows show striking similarities to
the infrared observations. It is pointed out that the high density dust regions
preferentially collect on the flanks of the billows. To get agreement with the
observed Kelvin-Helmholtz ripples, the assumed geometry between the background
radiation, the billows and the observer is seen to be of critical importance.Comment: 8 pages, 10 figure
Implementation of Research and Development Based on Patent Natural Ingredients and Potential Utilization of Tradition Medicine
. The results of research and development based on natural ingredients for traditional medicines become an interesting topic to discuss at this point; it's shown from increasing number in utilization. The use of traditional medicine especially on natural ingredients at this moment becomes effective solution to increase the level of market acceptance in herbal extracts, including an affordable purchase from potential utilization of natural resources which are owned. By using Matheo Patent XE Ver 10.2 as methodology of searching, we can know potentials useful through strategy, research and development, patent analysis and patent collaboration among users in utilization of Natural Ingredient for Traditional Medicine. From the data result shows majority in the field of chemistry for human necessity related to Health; Amusement; Medical or Veterinary Science; Hygiene sectors with total patent 108, family 65. The use of patent analysis is a way to find how the development of technology and products that have been produced and how commercial processes connecting with technology users, especially in traditional medicine. From the data that exist in particular of patents, it is critical to identify the number of patents that has been registered through the innovation process development including technology dissemination is used
Military-Affiliated Student Experiences in Post-Secondary Education
AbstractThis paper is intended to learn about the experiences of military-affiliated students in post-secondary education by surveying veterans, service members, and dependents on what resources they have available, what resources they would like to have, and comparing between 2-year, 4-year, public, and private institutions. Participants were surveyed at five different institutions. Three closed-ended questions asked for background and other disadvantaged identifiers. Three open-ended questions ask in detail about their experiences at their institution. Students at public 4-year institutions received the best assistance with room to improve. Institutions of higher learning would benefit their military-affiliated students by providing a military-affiliated success center as a one-stop with all possible resources in one location. Institutions that can not feasibly provide this could offer a military-affiliated orientation to cover resources and benefits. There should be more efforts to recruit, retain, and graduate military-affiliated students
On local convergence of stochastic global optimization algorithms
In engineering optimization with continuous variables, the use of Stochastic Global Optimization (SGO) algorithms is popular due to the easy availability of codes. All algorithms have a global and local search character, where the global behaviour tries to avoid getting trapped in local optima and the local behaviour intends to reach the lowest objective function values. As the algorithm parameter set includes a final convergence criterion, the algorithm might be running for a while around a reached minimum point. Our question deals with the local search behaviour after the algorithm reached the final stage. How fast do practical SGO algorithms actually converge to the minimum point? To investigate this question, we run implementations of well known SGO algorithms in a final local phase stage.- This paper has been supported by The Spanish Ministry (RTI2018-095993-B-I00) in part financed by the European Regional Development Fund (ERDF) and by FCT Fundacao para a Ciencia e Tecnologia within the Project Scope: UIDB/00319/2020
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