3,233 research outputs found
Insect (Arthropoda: Insecta) Composition in the Diet of Ornate Box Turtles (Terrapene ornata ornata) in Two Western Illinois Sand Prairies, with a New State Record for Cyclocephala (Coleoptera: Scarabaeidae)
A study of fecal samples collected over a two-year period from juvenile ornate box turtles (Terrapene ornata ornata Agassiz) revealed diets consisting of six orders of insects representing 19 families. Turtles were reared in captivity from eggs harvested from local, wild populations, and released at two remnant prairies. Identifiable insect fragments were found in 94% of samples in 2013 (n=33) and 96% in 2014 (n=25). Frequency of occurrence of insects in turtle feces is similar to results reported in previous studies of midwestern Terrapene species. A comparison of insect composition presented no significant difference between release sites. There is no significant difference in consumed insect species between turtles released into or outside of a fenced enclosure at the same site. Specimens of Cyclocephala longula LeConte collected during this study represent a new state record for Illinois
Microstructural and Corrosion Properties of Cold Rolled Laser Welded UNS S32750 Duplex Stainless Steel
The main goal of this work was to study the effect of plastic deformation on weldability of duplex stainless steel (DSS). It is well known that plastic deformation prior to thermal cycles can enhance secondary phase precipitation in DSS which can lead to significant change of the ferrite-austenite phase ratio. From this point of view one of the most important phase transformation in DSS is the eutectoid decomposition of ferrite. Duplex stainless steels (DSSs) are a category of stainless steels which are employed in all kinds of applications where high strength and excellent corrosion resistance are both required. This favorable combination of properties is provided by their biphasic microstructure, consisting of ferrite and austenite in approximately equal volume fractions. Nevertheless, these materials may suffer from several microstructural transformations if they undergo heat treatments, welding processes or thermal cycles. These transformations modify the balanced phase ratio, compromising the corrosion and mechanical properties of the material. In this paper, the microstructural stability as a consequence of heat history due to welding processes has been investigated for a super duplex stainless steel (SDSS) UNS S32750. During this work, the effects of laser beam welding on cold rolled UNS S32750 SDSS have been investigated. Samples have been cold rolled at different thickness reduction (\u3b5 = 9.6%, 21.1%, 29.6%, 39.4%, 49.5%, and 60.3%) and then welded using Nd:YAG laser. Optical and electronical microscopy, eddy\u2019s current tests, microhardness tests, and critical pitting temperature tests have been performed on the welded samples to analyze the microstructure, ferrite content, hardness, and corrosion resistance. Results show that laser welded joints had a strongly unbalanced microstructure, mostly consisting of ferritic phase (~60%). Ferrite content decreases with increasing distance from the middle of the joint. The heat-affected zone (HAZ) was almost undetectable and no defects or secondary phases have been observed. Both hardness and corrosion susceptibility of the joints increase. Plastic deformation had no effects on microstructure, hardness or corrosion resistance of the joints, but resulted in higher hardness of the base material. Cold rolling process instead, influences the corrosion resistance of the base material
Contribuição de poleiros naturais e artificiais para a recuperação de ecossistemas florestais.
Resumo
Esperienze progettuali di edifici per attività natatorie
Alla città di Milano manca un centro natatorio di spicco atto ad ospitare eventi sportivi di caratura internazionale. L’articolo affronta il tema della progettazione di edifici per attività natatorie proponendo l’inquadramento di possibili soluzioni progettuali attraverso degli studi eseguiti nell’ambito del corso “Building Technology Studio” al Politecnico di Milano. I progetti sono contestualizzati nell’ambito di un quartiere originariamente pensato per il rapporto con l’acqua, ovvero Porto di Mare, sito alla periferia sud-est di Milano
Características das espécies vegetais dispersas por aves e morcegos e suas implicações na recuperação ou manutenção de ambientes florestais.
Editores técnicos: Marcílio José Thomazini, Elenice Fritzsons, Patrícia Raquel Silva, Guilherme Schnell e Schuhli, Denise Jeton Cardoso, Luziane Franciscon. EVINCI. Resumos
19F nuclear spin relaxation and spin diffusion effects in the single ion magnet LiYF4:Ho3+
Temperature and magnetic field dependences of the 19F nuclear spin-lattice
relaxation in a single crystal of LiYF4 doped with holmium are described by an
approach based on a detailed consideration of the magnetic dipole-dipole
interactions between nuclei and impurity paramagnetic ions and nuclear spin
diffusion processes. The observed non-exponential long time recovery of the
nuclear magnetization after saturation at intermediate temperatures is in
agreement with predictions of the spin-diffusion theory in a case of the
diffusion limited relaxation. At avoided level crossings in the spectrum of
electron-nuclear states of the Ho3+ ion, rates of nuclear spin-lattice
relaxation increase due to quasi-resonant energy exchange between nuclei and
paramagnetic ions, in contrast to the predominant role played by electronic
cross-relaxation processes in the low-frequency ac-susceptibility.Comment: 27 pages total, 5 figures, accepted for publication, Eur. Phys. J.
From cosmic deceleration to acceleration: new constraints from SN Ia and BAO/CMB
We use type Ia supernovae (SN Ia) data in combination with recent baryonic
acoustic oscillations (BAO) and cosmic microwave background (CMB) observations
to constrain a kink-like parametrization of the deceleration parameter ().
This -parametrization can be written in terms of the initial () and
present () values of the deceleration parameter, the redshift of the
cosmic transition from deceleration to acceleration () and the redshift
width of such transition (). By assuming a flat space geometry,
and adopting a likelihood approach to deal with the SN Ia data we obtain, at
the 68% confidence level (C.L.), that: ,
and when we combine
BAO/CMB observations with SN Ia data processed with the MLCS2k2 light-curve
fitter. When in this combination we use the SALT2 fitter we get instead, at the
same C.L.: , and
. Our results indicate, with a quite general and
model independent approach, that MLCS2k2 favors Dvali-Gabadadze-Porrati-like
cosmological models, while SALT2 favors CDM-like ones. Progress in
determining the transition redshift and/or the present value of the
deceleration parameter depends crucially on solving the issue of the difference
obtained when using these two light-curve fitters.Comment: 25 pages, 9 figure
Experimental analysis on steel reinforced glass beams at different temperatures
This work is funded by FEDER Funds, through the Operational Programme Competitiveness
Factors – COMPETE, and Portuguese Funds, through FCT - Foundation for Science and Technology, under the project PTDC/ECM/116609/2010, “S-GLASS: Structural Performance and
Design Rules of Glass Beams Externally Reinforced”.
In addition, The COST Action TU0905 ‘‘Structural Glass – Novel Design Methods and Next Generation Products’’ is also acknowledged.Whereas glass components were used as infill elements in the past, contemporary architectural concepts include glass components as load-bearing elements. Recent architectural trends and technological developments have brought about unprecedented opportunities in the use of glass in buildings. The increasingly daring structural applications of glass will continue to drive the development of structural glass elements with high post-failure resistances.
The present work aims to explore the concepts of structural performance of glass beams and the effectiveness of an embedded steel reinforcement system. The reinforcement system consists in embedding perforated stainless steel plates in the lamination process. The experimental study focuses on the effect of thermal actions and compares the use of soft foils and stiff foils (temperature ranging from approximately 16 ºC to 85 ºC).Fundação para a Ciência e a Tecnologia (FCT
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