10,754 research outputs found
Direct numerical simulation of 'short' laminar separation bubbles with turbulent reattachment
No full textDirect numerical simulation of the incompressible Navier–Stokes equations is used to study flows where laminar boundary-layer separation is followed by turbulent reattachment forming a closed region known as a laminar separation bubble. In the simulations a laminar boundary layer is forced to separate by the action of a suction profile applied as the upper boundary condition. The separated shear layer undergoes transition via oblique modes and [Lambda]-vortex-induced breakdown and reattaches as turbulent flow, slowly recovering to an equilibrium turbulent boundary layer. Compared with classical experiments the computed bubbles may be classified as ‘short’, as the external potential flow is only affected in the immediate vicinity of the bubble. Near reattachment budgets of turbulence kinetic energy are dominated by turbulence events away from the wall. Characteristics of near-wall turbulence only develop several bubble lengths downstream of reattachment. Comparisons are made with two-dimensional simulations which fail to capture many of the detailed features of the full three-dimensional simulations. Stability characteristics of mean flow profiles are computed in the separated flow region for a family of velocity profiles generated using simulation data. Absolute instability is shown to require reverse flows of the order of 15–20%. The three-dimensional bubbles with turbulent reattachment have maximum reverse flows of less than 8% and it is concluded that for these bubbles the basic instability is convective in nature
Two-pion femtoscopy in p-Pb collisions at root(NN)-N-S=5.02 TeV
No full textWe report the results of the femtoscopic analysis of pairs of identical pions measured in p-Pb collisions at root(NN)-N-S = 5.02 TeV. Femtoscopic radii are determined as a function of event multiplicity and pair momentum in three spatial dimensions. As in the pp collision system, the analysis is complicated by the presence of sizable background correlation structures in addition to the femtoscopic signal. The radii increase with event multiplicity and decrease with pair transverse momentum. When taken at comparable multiplicity, the radii measured in p-Pb collisions, at high multiplicity and low pair transverse momentum, are 10%-20% higher than those observed in pp collisions but below those observed in A-A collisions. The results are compared to hydrodynamic predictions at large event multiplicity as well as discussed in the context of calculations based on gluon saturation
5.6 kW peak power, nanosecond pulses at 274 nm from a frequency quadrupled Yb-doped fiber MOPA
No full textDataset for the paper:
He, J, Lin, D, Xu, L, Beresna, M, Zervas, M, Alam, S-U & Brambilla, G (2018) '5.6 kW peak power, nanosecond pulses at 274 nm from a frequency quadrupled Yb-doped fiber MOPA' in Optics Express
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Cis-Diastereoselectivity in Pictet–Spengler Reactions of L-Tryptophan and Electronic Circular Dichroism Studies
No full textThe diastereoselective synthesis of optically active 1,3-disubstituted tetrahydro-beta-carbolines using polar protic PictetSpengler cyclization of (S)-tryptophan methyl ester with five aldehydes RCHO (R-CH3, C2H5, C3H7, C4H9, and C6H5) was studied. As an alternate route, the cyclization of (S)-tryptophan with the same aldehydes and subsequent methylation of the resulting tetrahydro-beta-carboline carboxylic acids were also performed for comparison. 13C NMR and electronic circular dichroism (ECD) studies and time-dependent density functional theory ECD calculations data established the relative 1,3 cis/trans and the absolute configuration (1S,3S/ 1R,3S) of the synthesized compounds. The solid-state and solution ECD study of the prepared compounds, supported by ECD calculation and X-ray data, afforded a reliable ECD method for the configurational assignment of 1,3-disubstituted tetrahydro-beta-carbolines and revealed the stereochemical factors that determine the characteristic ECD data
Recommendation domains for pond aquaculture: country case study: development and status of freshwater aquaculture in Bangladesh
No full textThis report is an output of the project ôDetermination of high-potential aquaculture development areas and impact in Africa and Asiaö. This monograph is the case study for Bangladesh. Written in three parts, it describes the historical background, practices, stakeholder profiles, production levels, economic and institutional environment, policy issues, and prospects for aquaculture in the country. First, it documents the history and current status of the aquaculture in the country. Second, it assesses the technologies and approaches that either succeeded or failed to foster aquaculture development and discusses why. Third, it identifies the key reasons for aquaculture adoption.Freshwater aquaculture, Economic analysis, Trade, Ecosystems, Pond culture, Fish consumption, Food security, Policies, Regulations, Legislation, Socioeconomic aspects, Yield, Bangladesh,
Evaluation of hepatoprotective effects of crude methanolic extract of Datura metel L. In mice
No full textDatura metel has been recommended in several human disorders including a remedy for liver toxicity. The current study was designed to evaluate the hepatoprotective effect of methanolic extract of D. metel in animal model. Acute toxicity of methanolic crude extract of Datura metel (MEDM) was studied in animals in various doses 500-2000 mg/kg. Mice of either sex were divided into groups (n=6). One group received normal saline intraperitonially as negative control, while other gentamicin 100mg/kg for 8 days as positive control. 3rd group received 50mg/kg silymarin as standard, 4th group received 100mg/kg of MEDM, 5th group received 200mg/kg MEDM while 6th group received 300mg/kg MEDM and gentamicin 100mg/kg for 8 days. The blood samples were collected on 9th day and the animals were then dissected and the liver of all the animals were isolated. MEDM was found safe in acute toxicity test at various doses up to 2000 mg/kg. The levels of serum glutamic pyruvic transaminase and alkaline phosphatase were elevated significantly with gentamicin treatment which significantly down-regulated by MEDM (100, 200 and 300 mg/kg) in a dose dependent manner.. The histological examination showed that the MEDM has markedly treated the inflammatory infiltrate, fatty changes and congested blood vessels which were induced by gentamicin. The findings of our study thus proved the absolute of MEDM in acute toxicity test; followed by significant hepatoprotective effect in gentamicin induced hepatotoxic mice
Shape studies of quark jets versus gluon jets at s=10 GeV
No full textcomplete author list:
Alam M.; Kim I.; Nemati B.; O'Neill J.; Romero V.; Severini H.; Sun C.; Wang P.; Zoeller M.; Crawford G.; Fulton R.; Gan K.; Kagan H.; Kass R.; Lee J.; Malchow R.; Morrow F.; Sung M.; White C.; Whitmore J.; Wilson P.; Butler F.; Fu X.; Kalbfleisch G.; Lambrecht M.; Skubic P.; Snow J.; Wang P.; Bortoletto D.; Brown D.; Dominick J.; McIlwain R.; Miao T.; Miller D.; Modesitt M.; Schaffner S.; Shibata E.; Shipsey I.; Battle M.; Ernst J.; Kroha H.; Roberts S.; Sparks K.; Thorndike E.; Wang C.; Artuso M.; Goldberg M.; Haupt T.; Horwitz N.; Kennett R.; Moneti G.; Playfer S.; Rozen Y.; Rubin P.; Skwarnicki T.; Stone S.; Thulasidas M.; Yao W.; Zhu G.; Stroynowski R.; Barnes A.; Bartelt J.; Csorna S.; Egyed Z.; Jain V.; Letson T.; Mestayer M.; Sheldon P.; Akerib D.; Barish B.; Chadha M.; Cowen D.; Eigen G.; Miller J.; Urheim J.; Weinstein A.; Menary S.; Morrison R.; Nelson H.; Richman J.; Tajima H.; Schmidt D.; Sperka D.; Witherell M.; Acosta D.; Masek G.; Ong B.; Paar H.; Sivertz M.; Procario M.; Daoudi M.; Ford W.; Johnson D.; Lingel K.; Lohner M.; Rankin P.; Smith J.; Alexander J.; Bebek C.; Berkelman K.; Besson D.; Browder T.; Cassel D.; Cheu E.; Coffman D.; Drell P.; Ehrlich R.; Garcia-Sciveres M.; Geiser B.; Gittelman B.; Gray S.; Hartill D.; Heltsley B.; Honscheid K.; Jones C.; Kandaswamy J.; Katayama N.; Kim P.; Kreinick D.; Ludwig G.; Masui J.; Mevissen J.; Mistry N.; Nandi S.; Ng C.; Nordberg E.; O'Grady C.; Patterson J.; Peterson D.; Riley D.; Sapper M.; Selen M.; Worden H.; Worris M.; Würthwein F.; Avery P.; Freyberger A.; Rodriguez J.; Stephens R.; Yelton J.; Henderson S.; Kinoshita K.; Liu T.; Saulnier M.; Wilson R.; Yamamoto H.; Sadoff A.; Ammar R.; Ball S.; Baringer P.; Coppage D.; Davis R.; Hancock N.; Kelly M.; Kwak N.; Lam H.; Ro S.; Kubota Y.; Lattery M.; Nelson J.; Perticone D.; Poling R.; Schrenk S.; Wang R.; Wang R.; Poling R.; Schrenk S.; Nelson J.; Perticone D.; Alam M.S
menghayati kodrat alam: robert frost penyair alam
No full textHidup bahagia adalah idaman setiap insan manuaia, n a m u n tidak semus manuaia mampu menoapinya. Untuk itu diperlukanpengetahuan dan penghayatan tentang sifat-sifat atau kodrat hidup itu sendiri. Tanpa semuanya manuaia seringkali menga -Iami kekeoewaan, kebingungan bahkan frustasi. Robert Prost, aalah seorang penyair Amerika yang terkenal di abed duapuluh, memerikan perjuangan manusia dalam menemukan sifat-sifat atau kodrat hidup alam dalam sejumlah karyanya yang tertulia aepanjang perjalanan hidupnya. Froat percaya ,bahwa alam itu kaya, tidak hanya ada makanan atau seauatu yang dapat dinaikmati manuaia seoara lahir, tetapi juga ada hal-hal yang bersifat sp~ritual didelamnya. aeperti r a s a peroaya diri, keseimbangan dan keselaraaan d a 1 a m hidup.Namun Froat juga tidak sepenuhnya peroaya. bahwa alam selalu ramah terhadap manuaia. Dalsm beberapa puisinya, dia meng gambarkan manusia aeringkali menjumpai alam yang indifferent atau acuh-takacuh terhadap manuaia, menakUtkan dan bah k a n menganaam keselamatan manueia
Interdependent multi-issue negotiation for energy exchange in remote communities
No full textWe present a novel negotiation protocol to facilitate energy exchange between off-grid homes that are equipped with renewable energy generation and electricity storage. Our protocol imposes restrictions over negotiation such that it reduces the complex interdependent multi-issue negotiation to one where agents have a strategy profile in subgame perfect Nash equilibrium. We show that our negotiation protocol is tractable, concurrent, scalable and leads to Pareto-optimal outcomes in a decentralised manner. We empirically evaluate our protocol and show that, in this instance, a society of agents can (i) improve the overall utilities by 14% and (ii) reduce their overall use of the batteries by 37
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