74,908 research outputs found
Emanation thermal analysis study of a sol-gel precursor for silica-titania waveguides
No full textEmanation Thermal Analysis (ETA) was demonstrated as a tool for the characterization of microstructure
changes of a sol–gel precursor for silica–titania layers deposited on the glass plate to be
used as planar waveguides. Temperature ranges of 280–330 and 380–500°C, respectively, in which
the densification of the layers took place, were determined by ETA under in situ conditions of the
sample heating. Results of thermogravimetry were compared with the ETA data
The Benefits of Being Economics Professor A (and not Z)
No full textAlphabetic name ordering on multi-authored academic papers, which is the convention in the economics discipline and various other disciplines, is to the advantage of people whose last name initials are placed early in the alphabet. As it turns out, Professor A, who has been a first author more often than Professor Z, will have published more articles and experienced afaster growth rate over the course of her career as a result of reputation and visibility. Moreover, authors know that name ordering matters and indeed take ordering seriously: Several characteristics of an author group composition determine the decision to deviate from the default alphabetic name order to a significant extent.performance measurement, incentives, economists, name ordering
BARDAKÇI KÖYÜ ÇÖMLEKÇİLİĞİNİN GELİŞİM SÜRECİ
No full textBardakçı köyü Van Bölgesi söz konusu olduğunda özellikle bir çömlek üretim merkezi olarak akla gelmektedir. Neredeyse Urartulardan günümüze kadar uzanan seramik serüveninin bir parçası haline geldiği kabul edilir. 1970 yıllara kadar kesintisiz devam eden çömlekçilik üretimi o yıllardan sonra plastiğin yaygın kullanım alanı bulmasıyla, Bardakçı köyünde çömlekçilik zanaatı kesintiye uğramış ve atölyeler kapanmıştır. Bu bildiride Bardakçı Köyü arazisi satın alınarak üzerine inşa edilen Van Yüzüncü Yıl Üniversitesinin Bardakçı da yok olan çömlekçiliğin yeniden hayat bulması konusundaki önemli rolünden bahsedilecektir. Ayrıca Van Yüzüncü Yıl Üniversitesi Güzel Sanatlar Fakültesi Seramik Bölümünün Bardakçı Köyü Çömlekçiliğinin gelişimine olan katkısı anlatılacaktır.</p
Final word on Jersey Dutch
No full textIn this article, William Z. Shetter compares and contrasts the dialects that developed between different Dutch colonies in the New World. He explores in-depth the nuances of Jersey Dutch, and provides theories to explain how Dutch and colonial languages blended. The article is reprinted from American Speech, December 1958, Volum XXXIII, No. 4
Charakterystyka mlek fermentowanych po procesie pasażowania kultur starterowych®
No full textThe aim of this study presented in the article was an investiga- tion the influence of the passaging process of starter cultures on selected properties of fermented milks. The study involved fermentation of cow’s milk with three starter cultures containing bacteria from the genera Lactobacillus, Streptococcus, and Bifidobacterium. The obtained fermented milk samples were used as starters to perform another round of fermentation and fermentation after 3 days of refrigerated storage of the samples. The pH, number of bacterial cells, and sugar pro file of the fermented milk were then determined. The results showed that passage is an important factor determining the dynamics of the lactic acid fermentation process. The passage process significantly influenced the number of bacterial cells in milk. It was also observed that after the first and second passages, the fermented milk samples showed lower lactose content. The present study provides useful references on the metabolism of lactic acid bacteria and bifidobacteria in fermented milks.Celem pracy zaprezentowanej w artykule było zbadanie wpływu procesu pasażowania kultur starterowych na wybrane właściwości mlek fermentowanych. Badania obejmowały fermentację mleka krowiego trzema kulturami starterowymi zawierającymi bakterie z rodzajów Lactobacillus, Streptococcus i Bifidobacterium. Otrzymane próbki mleka fermentowanego posłużyły jako startery do przeprowadzenia kolejnej rundy fermentacji i fermentacji po 3 dniach przechowywania próbek w warunkach chłodniczych. Następnie określono pH, liczbę komórek bakteryjnych i profil cukru w próbkach mleka fermentowanego. Wyniki wykazały, że pasaż jest ważnym czynnikiem determinującym dynamikę procesu fermentacji kwasu mlekowego. Proces pasażowania istotnie wpłynął na liczbę komórek bakteryjnych w mleku. Zaobserwowano również, że po pierwszym i drugim pasażu próbki mleka fermentowanego wykazywały niższą zawartość laktozy. Niniejsze badanie dostarcza użytecznych informacji na temat metabolizmu bakterii kwasu mlekowego i bifidobakterii w mleku fermentowanym
Logarithmic variance profiles and the corresponding f-1 spectra of temperature fluctuations in turbulent Rayleigh-Bénard convection
No full textWe report experimental results for the temperature variance 2(z) and the corresponding frequency spectra P(f) in turbulent Rayleigh-Bénard convection (RBC) in a cylindrical sample of aspect ratioT= D/L = 1:00 (D = 1:12 m is the diameter and L = 1:12 m the height). The measurements were conducted in the Rayleigh-number range 1011 < Ra < 1:35 1014 and Pr ' 0:8. For Ra = 1:35x1014, 2(z) could be described well by a logarithmic dependence on the vertical position z in a range of z 1 < z < z 2 with z 1 ' 70 and z 2 = 0:1L. Here L=(2Nu) is the thickness of a thin thermal sublayer adjacent to the horizontal plate where the heat flux (denoted by the Nusselt number Nu) is carried mostly by thermal diffusion. In the log layer, we found that the temperature spectra had a significant frequency range over which P(f) f with close to 1. As Ra decreased, increased so that the log layer became thinner. At Ra = 2:05 1011, z 2 < z 1 and therefore there was no range for a log layer. Correspondingly, the temperature spectrum near the horizontal plate did not have the f1 scaling form either
Statistics of the subgrid scales after the shock-turbulence interaction
No full textThe interaction of a normal shock with isotropic turbulence (IT) represents a basic problem for studying some of the phenomena associated with high speed flows, such as hypersonic flight, supersonic combustion and Inertial Confinement Fusion (ICF). In general, in practical applications, the shock width is much smaller than the turbulence scales and the upstream turbulent Mach number is modest. In this case, recent high resolution shock-resolved Direct Numerical Simulations (DNS) (Ryu and Livescu, J. Fluid Mech., 756, R1, 2014) show that the interaction can be described by the Linear Interaction Approximation (LIA). By using LIA to alleviate the need to solve the shock, DNS post-shock data can be generated at much higher Reynolds numbers than previously possible. Here, such results with Taylor Reynolds number around are used to investigate the properties of the subgrid scales (SGS). In particular, it is shown that the shock interaction decreases the asymmetry of the SGS dissipation PDF as the shock Mach number increases, with a significant enhancement in size of the regions and magnitude of backscatter
Transition to turbulence in a qblique shock-wave/boundary-layer interaction at M=15
No full textDirect numerical simulations are carried out for different forcing techniques to trigger transition during the interaction between an oblique shock-wave and a laminar boundary-layer at M = 1.5. Three forcing methods are used: a) forcing of oblique unstable modes, whose shape and behaviour are determined by the local linear stability theory, b) broadband free-stream acoustic disturbances, and c) a cold plasma flow control device. While the oblique-mode breakdown is dominant for low-amplitude forcing, long streaky structures drive the transition process in a high-amplitude disturbance environment. LES are also performed on the experimental setup by the Institute of Theoretical and Applied Mechanics (ITAM) from Novosibirsk State University with cold plasma actuation. As well as the disturbance type, the effect of Reynolds number and forcing amplitude will be investigated
Triangular Constellations in Flows
No full textParticles advected on the surface of a fluid can exhibit fractal clustering. The local structure of a fractal set is described by its dimension , which is the exponent of a power-law relating the mass in a ball to its radius : . It is desirable to characterise the {\em shapes} of constellations of points sampling a fractal measure, as well as their masses. The simplest example is the distribution of shapes of triangles formed by triplets of points, which we investigate for fractals generated by chaotic dynamical systems. The most significant parameter describing the triangle shape is the ratio of its area to the radius of gyration squared. We show that the probability density of has a phase transition: is independent of and approximately uniform below a critical flow compressibility , which we estimate. For the distribution appears to be described by two power laws: when , and when
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