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1.
Chien-Jung Huang Shao-Ching Huang Susan M. White Sanjay M. Mallya Jeff D. Eldredge 《Theoretical and Computational Fluid Dynamics》2016,30(1-2):87-104
Obstructive sleep apnea (OSA) is a medical condition characterized by repetitive partial or complete occlusion of the airway during sleep. The soft tissues in the airway of OSA patients are prone to collapse under the low-pressure loads incurred during breathing. This paper describes efforts toward the development of a numerical tool for simulation of air–tissue interactions in the upper airway of patients with sleep apnea. A procedure by which patient-specific airway geometries are segmented and processed from dental cone-beam CT scans into signed distance fields is presented. A sharp-interface embedded boundary method based on the signed distance field is used on Cartesian grids for resolving the airflow in the airway geometries. For simulation of structure mechanics with large expected displacements, a cut-cell finite element method with nonlinear Green strains is used. The fluid and structure solvers are strongly coupled with a partitioned iterative algorithm. Preliminary results are shown for flow simulation inside the three-dimensional rigid upper airway of patients with obstructive sleep apnea. Two validation cases for the fluid–structure coupling problem are also presented. 相似文献
2.
Surendra V. Singh Jayaram Vishakantaiah Jaya K. Meka Vijayan Sivaprahasam Vijayanand Chandrasekaran Rebecca Thombre Vijay Thiruvenkatam Ambresh Mallya Balabhadrapatruni N. Rajasekhar Mariyappan Muruganantham Akshay Datey Hugh Hill Anil Bhardwaj Gopalan Jagadeesh Kalidevapura P. J. Reddy Nigel J. Mason Bhalamurugan Sivaraman 《Molecules (Basel, Switzerland)》2020,25(23)
The building blocks of life, amino acids, are believed to have been synthesized in the extreme conditions that prevail in space, starting from simple molecules containing hydrogen, carbon, oxygen and nitrogen. However, the fate and role of amino acids when they are subjected to similar processes largely remain unexplored. Here we report, for the first time, that shock processed amino acids tend to form complex agglomerate structures. Such structures are formed on timescales of about 2 ms due to impact induced shock heating and subsequent cooling. This discovery suggests that the building blocks of life could have self-assembled not just on Earth but on other planetary bodies as a result of impact events. Our study also provides further experimental evidence for the ‘threads’ observed in meteorites being due to assemblages of (bio)molecules arising from impact-induced shocks. 相似文献
3.
Electrical resistance measurements are reported for amorphous In20Te80 and Cu25Au5Te70 alloys up to a pressure of 80 Kbar using a Bridgman anvil apparatus and a four lead arrangement to measure resistances. The amorphous samples are produced by liquisol quenching. The resistance shows time dependent changes which are analysed in detail. The contention that there is a pressure-induced transformation from the amorphous to the crystalline phase is confirmed by X-ray diffraction of samples recovered after they were pressurised to 35 Kbar in a hydrostatic environment. 相似文献
4.
Ambresh Shivaji Subhadip Mitra Pankaj Agrawal 《The European Physical Journal C - Particles and Fields》2012,72(3):1922
In order to solve the hierarchy problem, several extra-dimensional models have received considerable attention. We have considered
a process where a Higgs boson is produced in association with a KK-graviton (G
KK) at the LHC. At the leading order, this process occurs through the gluon fusion mechanism gg→hG
KK via a quark loop. We compute the cross section and examine some features of this process in the ADD model. We find that the
quark in the loop does not decouple in the large quark-mass limit just as in the case of gg→h process. We compute the cross section of this process for the case of the RS model also. We examine the feasibility of this
process being observed at the LHC. 相似文献
5.
Electron and x-ray diffraction studies on Al86Fe14, Al82Fe18 and Al75Fe25 quasicrystals 总被引:1,自引:0,他引:1
J A Sekhar T Rajasekharan P Rama Rao G Parthasarathy S Ramkumar E S R Gopal C S Lakshmi R M Mallya 《Pramana》1986,27(1-2):267-273
Electron and x-ray diffraction experiments on the metlt-spun Al100−x
Fe
x
(x=14, 18, 25) alloys are carried out. It is observed that all the melt-spun alloys possessing the quasi-crystalline phases
have icosahedral point-group symmetry.
The authors felicitate Prof. D S Kothari on his eightieth birthday and dedicate this paper to him on this occasion. 相似文献
6.
Reactivity with hydrogen of pure iron oxide and of iron oxides doped with oxides of Mn,Co, Ni and Cu
Using dynamic TG in H2, X-ray powder diffraction and Mössbauer Spectroscopy the reactivities fot hydrogen reduction of Fe2O3 prepared at different temperatures, Fe2O3 doped with oxides of Mn, Co, Ni and Cu prepared at 300C from nitrate precursors and intermediate spinels derived from above samples during reduction have been explored. The reactivity is higher for finely divided Fe2O3 prepared at 250C. The reduction is retarded by Mn, marginally affected by Co and accelerated by Ni and Cu, especially at higher (5 at.%) dopant concentration. These reactivities confirmed also by isothermal experiments, are ascribed to the nature of disorder in the metastable intermediate spinels and to hydrogen spill over effects.
The authors thank Dr. Chitra Sankar for her help and useful discussions on the Mössbauer studies carried out. They also thank A. V. Narayan and D. Molliah for their assistance with the figures. 相似文献
Zusammenfassung Mittels Debye-Scherrer-Aufnahmen, Mössbauer-Spektroskopie und DTG in WasserstoffatmosphÄre wurde die ReaktivitÄt bezüglich der Reduktion mit Wasserstoff von Fe2O3, versetztem Fe2O3 und von intermediÄren Spinellen aus der Reduktion obiger Proben untersucht. Die reinen Fe2O3-Proben wurden bei verschiedenen Temperaturen hergestellt. Mit Oxiden von Mn, Co, Ni und Cu versetzte Fe2O3-Proben wurden bei 300C aus Nitrat-VorlÄufern hergestellt. Eine höhere AktivitÄt besteht für fein zerkleinertes, bei 250C hergestelltes Fe2)O3. Die Reduktion wird durch Mn verzögert, durch Co unwesentlich beeinflu\t und durch Ni und Cu beschleunigt, besonders bei höheren Konzentrationen (5 mol%). Diese ReaktivitÄten, die auch durch isotherme Experimente bestÄtigt werden konnten, wurden der Ungeordnetheit in den metastabilen intermediÄren Spinellen sowie Wasserstoff-überschu\-Effekten zugeschrieben.
The authors thank Dr. Chitra Sankar for her help and useful discussions on the Mössbauer studies carried out. They also thank A. V. Narayan and D. Molliah for their assistance with the figures. 相似文献
7.
V.R.Pai Verneker D. Seetharamacharyulu R.M. Mallya 《Journal of solid state chemistry》1981,39(2):154-160
Ammonium perchlorate-potassium perchlorate mixtures, upon pelletization, form a series of homogeneous solid solutions as manifested by X-ray powder diffractograms. Scanning electron microscopic studies throw light on the mechanism of the solid-solution formation. Solid solutions of ammonium perchlorate-potassium perchlorate have also been obtained by a modified cocrystallization technique. The thermal and combustion behavior of the solid solutions have also been studied, using the DTA technique and the Crawford strand burner. 相似文献
8.
Narayani Mallya Vaneica Young 《Journal of Electron Spectroscopy and Related Phenomena》1981,24(1):43-54
Angular distribution XPS has been employed for the first time to follow the changes in the electronic structure of gold as it is implanted into Al2O3 overlayers on aluminium by recoil. The rudimentary aspects of the implantation process may be followed by observing the Au 4f intensity as a function of primary ion dose for discrete values of θ. Intensity versus primary ion dose curves show three distinct regions — a continuous-film region, an island and cluster region, and an implanted-atom region. For this system, while only gold atoms are introduced into the substrate, the surface contains clusters of gold even for very low gold concentrations. The valence-band density of states shows good agreement with a theoretical spectrum calculated using a unity polarizability model previously described. 相似文献
9.
Noor Shahina Begum D. E. Vasundhara C. R. Girija M. Narendra Mallya Gopalpur Nagendrappa 《Journal of chemical crystallography》2008,38(7):547-551
Abstract The crystal and molecular structure of cis-1-chloro-2-amino-1-trimethylsilylcycloheptane picrate (cis-CATP) is determined and discussed along with its spectroscopy. The crystal structure of this compound (C10H23SiClN+ C6H2N3O7−) consists of ammonium cycloheptane cation and picrate anion stabilized by interionic N–H···O and C–H···O interactions leading
to extended hydrogen bonded network structure. Apart from the less common syn addition of nitrosylchloride to 1-trimethylsilylcycloheptene ring, an interesting and unexpected reversal of regiochemistry
of addition is revealed.
Index Abstract The preparation of cis-1-chloro-2-ammonium-1-trimethylsilylcycloheptane picrate is described and its crystal structure is determined and discussed.
相似文献
10.