1,762 research outputs found
SAND FULGURITES FROM NEBRASKA Their structure and formative factors
So much has been written during the past century on the origin, structure and occurrence of fulgurites, or lightning tubes, found in many parts of the world that it would seem as though little remains to be added to the literature on the subject; but the discovery of a considerable number of unusually large and complete specimens in Holt and Stanton Counties, Nebraska, which exhibit remarkable definition of the particular features that have occasioned so much controversy regarding their formative processes, has added an important type to the representatives of this phenomenon and afforded clearer interpretation of the origin of certain disputed structures
SAND FULGURITES FROM NEBRASKA Their structure and formative factors
So much has been written during the past century on the origin, structure and occurrence of fulgurites, or lightning tubes, found in many parts of the world that it would seem as though little remains to be added to the literature on the subject; but the discovery of a considerable number of unusually large and complete specimens in Holt and Stanton Counties, Nebraska, which exhibit remarkable definition of the particular features that have occasioned so much controversy regarding their formative processes, has added an important type to the representatives of this phenomenon and afforded clearer interpretation of the origin of certain disputed structures
Extending CFD Modeling to Near-Continuum Flows Using Enhanced Thermophysical Modeling
The constitutive relations found in traditional Navier-Stokes-based computational fluid dynamics solvers are known to be limited in altitude. The presence of nonequilibrium phenomena beyond what these methods are able to predict becomes more prevalent at higher altitudes, or increasing Knudsen number. The bulk viscosity, normally assumed to be zero in most computational fluid dynamics applications, is examined as a means of increasing the range of applicability of computational fluid dynamics. The bulk viscosity model used was from recent calculations available in the literature, from a new anisotropic potential energy surface, and is restricted to temperatures below 2000 K. The normal shock problem was solved for Mach numbers up to ten, using the bulk viscosity model. The bulk viscosity provided improvement in the agreement with observations of normal shock thickness for Mach numbers up to ten. Two axisymmetric, experimentally observed flows were solved with and without the bulk viscosity, and compared to DSMC solutions of a previous work. Improvement of surface heat transfer agreement with observation was found for a hollow-cylinder are axisymmetric body. Improvement of separation point prediction was found for an axisymmetric double cone
Protostellar Disk Evolution Over Million-Year Timescales with a Prescription for Magnetized Turbulence
Magnetorotational instability (MRI) is the most promising mechanism behind
accretion in low-mass protostellar disks. Here we present the first analysis of
the global structure and evolution of non-ideal MRI-driven T-Tauri disks on
million-year timescales. We accomplish this in a 1+1D simulation by calculating
magnetic diffusivities and utilizing turbulence activity criteria to determine
thermal structure and accretion rate without resorting to a 3-D
magnetohydrodynamical (MHD) simulation. Our major findings are as follows.
First, even for modest surface densities of just a few times the minimum-mass
solar nebula, the dead zone encompasses the giant planet-forming region,
preserving any compositional gradients. Second, the surface density of the
active layer is nearly constant in time at roughly 10 g/cm2, which we use to
derive a simple prescription for viscous heating in MRI-active disks for those
who wish to avoid detailed MHD computations. Furthermore, unlike a standard
disk with constant-alpha viscosity, the disk midplane does not cool off over
time, though the surface cools as the star evolves along the Hayashi track. The
ice line is firmly in the terrestrial planet-forming region throughout disk
evolution and can move either inward or outward with time, depending on whether
pileups form near the star. Finally, steady-state mass transport is a poor
description of flow through an MRI-active disk. We caution that MRI activity is
sensitive to many parameters, including stellar X-ray flux, grain size,
gas/small grain mass ratio and magnetic field strength, and we have not
performed an exhaustive parameter study here.Comment: Accepted for publication in Astrophysical Journal. 19 pages,
including 8 figure
Bioetanol dari Limbah Kulit Singkong (Manihot Esculenta Crantz) melalui Proses Fermentasi
Carbohydrates can be obtained from tubers such as cassava. Cassava is a plant from family euphorbiaceae and typical tropical plants. Cassava peel is a major waste that contains carbohydrates. The peel of cassava can be used as an energy source, namely ethanol.The purpose of this study is to determine the contents of ethanol through the fermentation process of cassava peel where obtainable from Malino village, Batu Daka West, Tojo Una-Una. The parameters in this study was content of ethanol that was obtained by fermentation using saccaromyces cerevisiae yeast. The fermentation process was conducted by varying day of fermentation, 4, 6, 8, and 10 days. The results showed the fermentation of ethanol with time variation respectively is 4.50, 5.20, 6.00 and 4.00%. In conclusion, it can be said that the highest ethanol content is 6.00% with the fermentation time of 8 days
Transcriptional landscape of psoriasis identifies the involvement of IL36 and IL36RN
Background
In present study we performed whole transcriptome analysis in plaque psoriasis patients and compared lesional skin with non-lesional skin and with the skin from healthy controls. We sequenced total RNA from 12 lesional (LP), 12 non-lesional (NLP) and from 12 normal (C) skin biopsies.
Results
Compared with previous gene expression profiling studies we had three groups under analysis - LP, NLP and C. Using NLP samples allows to see the transcriptome of visually normal skin from psoriasis patient. In LP skin S100A12, S100A7A, LCE3E, DEFB4A, IL19 were found up regulated. In addition to already these well-described genes, we also found several other genes related to psoriasis. Namely, KLK9, OAS2, OAS3, PLA2G, IL36G, IL36RN were found to be significantly and consistently related to the psoriatic lesions and this finding is supported also by previous studies. The genes up-regulated in the LP samples were related to the innate immunity, IL17 and IL10 networks. In NLP samples innate immunity and IL17 network were activated, but activation of IL10 network was not evident. The transcriptional changes characteristic in the NLP samples can be considered as a molecular signature of “dormant psoriasis”.
Conclusions
Taken together, our study described the transcriptome profile characteristic for LP and NLP psoriatic skin. RNA profile of the NLP skin is in between the lesional and healthy skin, with its own specific pattern. We found that both LP and NLP have up-regulated IL17 network, whereas LP skin has up regulated IL10 related cytokines (IL19, IL20, IL24). Moreover, IL36G and IL36RN were identified as strong regulators of skin pathology in both LP and NLP skin samples, with stronger influence in LP samples
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