205 research outputs found
Examination of Technology in Turkish Social Studies Curricula
AbstractThis study is designed in descriptive model because it aims to analyze 4th, 5th, 6th and 7th grade social studies curricula in a technology focused view. In this context, document analysis technique was used which is a qualitative research method. Learning areas, acquisitions and skills in social studies curricula are considered in evaluation process. In conclusion, it was seen that in social studies curricula, Science,Technology and Society learning is directly technology oriented and this learning area has strict connections with others. Technology oriented activities are also implemented as needed in other learning areas. Besides, it was determined that there are 23 technology oriented acquisitions in 4 th, 5 th, 6 th and 7 th grade social studies curricula in Turkey. Six of them are in the 4th grade, six of them are in the 5th grade, five of them are in the 6th grade and six of them in the 7th grade. In this context, technology oriented acquisitions formed 13,2% of whole acquisitions in curricula (total 174). In skill dimension “using information technologies” skill is technology oriented and it is towards the effective usage of technology
Computational Simulation of Thermal and Spattering Phenomena and Microstructure in Selective Laser Melting of Inconel 625
AbstractComputational modelling of Laser Powder Bed Fusion (L-PBF) processes such as Selective laser Melting (SLM) can reveal information that is hard to obtain or unobtainable by in-situ experimental measurements. A 3D thermal field that is not visible by the thermal camera can be obtained by solving the 3D heat transfer problem. Furthermore, microstructural modelling can be used to predict the quality and mechanical properties of the product. In this paper, a nonlinear 3D Finite Element Method based computational code is developed to simulate the SLM process with different process parameters such as laser power and scan velocity. The code is further improved by utilizing an in-situ thermal camera recording to predict spattering which is in turn included as a stochastic heat loss. Then, thermal gradients extracted from the simulations applied to predict growth directions in the resulting microstructure
Driven and Non-Driven Surface Chaos in Spin-Glass Sponges
A spin-glass system with a smooth or fractal outer surface is studied by
renormalization-group theory, in bulk spatial dimension d=3. Independently
varying the surface and bulk random-interaction strengths, phase diagrams are
calculated. The smooth surface does not have spin-glass ordering in the absence
of bulk spin-glass ordering and always has spin-glass ordering when the bulk is
spin-glass ordered. With fractal (d>2) surfaces, a sponge is obtained and has
surface spin-glass ordering also in the absence of bulk spin-glass ordering.
The phase diagram has the only-surface-spin-glass ordered phase, the bulk and
surface spin-glass ordered phase, and the disordered phase, and a special
multicritical point where these three phases meet. All spin-glass phases have
distinct chaotic renormalization-group trajectories, with distinct Lyapunov and
runaway exponents which we have calculated.Comment: 4 pages, 3 figure
Cooling of the Martian thermosphere by CO(2) radiation and gravity waves: an intercomparison study with two general circulation models
©2015. American Geophysical Union. All Rights Reserved. Observations show that the lower thermosphere of Mars (∼100-140 km) is up to 40 K colder than the current general circulation models (GCMs) can reproduce. Possible candidates for physical processes missing in the models are larger abundances of atomic oxygen facilitating stronger CO2 radiative cooling and thermal effects of gravity waves. Using two state-of-the-art Martian GCMs, the Laboratoire de Météorologie Dynamique and Max Planck Institute models that self-consistently cover the atmosphere from the surface to the thermosphere, these physical mechanisms are investigated. Simulations demonstrate that the CO2 radiative cooling with a sufficiently large atomic oxygen abundance and the gravity wave-induced cooling can alone result in up to 40 K colder temperature in the lower thermosphere. Accounting for both mechanisms produce stronger cooling at high latitudes. However, radiative cooling effects peak above the mesopause, while gravity wave cooling rates continuously increase with height. Although both mechanisms act simultaneously, these peculiarities could help to further quantify their relative contributions from future observations.The work was partially supported by German Science Foundation (DFG) grant ME2752/3-1. F.G.G. was funded by a CSIC JAE-Doc contract cofinanced by the European Social Fund. F.G.G. thanks the Spanish MICINN for funding support through the CONSOLIDER program ASTROMOL CSD2009-00038, and through project AYA2011-23552/ESP. E.Y. was partially supported by NASA grant NNX13AO36G.Peer Reviewe
Which morphological abnormalities better define the elongation of transverse aortic arch: a magnetic resonance angiography study
Background: The aim of the study is to investigate the relation between morphological abnormalities that might indicate elongation of transverse aortic arch (ETA) and various aortic and thoracic measurements, and to determine which morphological criteria define the elongated transverse arch better.Materials and methods: Patients under 40 years of age who underwent contrast enhanced thoracic magnetic resonance angiography were included in the study. Images were evaluated for the presence of morphological arch abnormalities such as late take off (LTO) of left subclavian artery (LSA), flattening of the arch, and kinking at the posterior or anterior contour of the lesser curvature. Various aortic and thoracic measurements, including the distance between the orifices of the left common carotid artery (LCCA) and LSA, were made. Statistical relation between morphological abnormalities and these measurements was analysed. The effect of morphological abnormalities and their combinations on the distance between LCCA and LSA orifices was evaluated by linear regression analysis.Results: Ninety three cases were included in the study. All morphological abnormalities and most of their combinations show statistically significant relation with longer LCCA to LSA distance. The parameters that most affected this distance were combination of flattening with LTO of LSA, anterior kinking and combination of anterior kinking with both flattening and LTO, respectively.Conclusions: Our study showed that the finding which best defines ETA is the combination of LTO and arch flattening. Therefore, we recommend using this combination in the diagnosis of ETA instead of the classical diagnostic criteria including combination of LTO and posterior kinking
Influence of gravity waves on the climatology of high-altitude Martian carbon dioxide ice clouds
Carbon dioxide (CO2) ice clouds have been routinely observed in the
middle atmosphere of Mars. However, there are still uncertainties concerning
physical mechanisms that control their altitude, geographical, and seasonal
distributions. Using the Max Planck Institute Martian General Circulation
Model (MPI-MGCM), incorporating a state-of-the-art whole atmosphere
subgrid-scale gravity wave parameterization (Yiğit et al., 2008), we
demonstrate that internal gravity waves generated by lower atmospheric
weather processes have a wide-reaching impact on the Martian climate.
Globally, GWs cool the upper atmosphere of Mars by ∼10 % and
facilitate high-altitude CO2 ice cloud formation. CO2 ice
cloud seasonal variations in the mesosphere and the mesopause region
appreciably coincide with the spatio-temporal variations of GW effects,
providing insight into the observed distribution of clouds. Our results
suggest that GW propagation and dissipation constitute a necessary physical
mechanism for CO2 ice cloud formation in the Martian upper atmosphere
during all seasons.</p
Investigation of spherical and cylindrical catural Iridium targets by photonuclear reaction
Renormalization and topological susceptibility on the lattice: SU(2) Yang-Mills theory
The renormalization functions involved in the determination of the
topological susceptibility in the SU(2) lattice gauge theory are extracted by
direct measurements, without relying on perturbation theory. The determination
exploits the phenomenon of critical slowing down to allow the separation of
perturbative and non-perturbative effects. The results are in good agreement
with perturbative computations.Comment: 12 pages + 4 figures (PostScript); report no. IFUP-TH 10/9
Nitric oxide biosensor uncovers diminished ferrous iron-dependency of cultured cells adapted to physiological oxygen levels
Iron is an essential metal for cellular metabolism and signaling, but it has adverse effects in excess. The physiological consequences of iron deficiency are well established, yet the relationship between iron supplementation and pericellular oxygen levels in cultured cells and their downstream effects on metalloproteins has been less explored. This study exploits the metalloprotein geNOps in cultured HEK293T epithelial and EA.hy926 endothelial cells to test the iron-dependency in cells adapted to standard room air (18 kPa O2) or physiological normoxia (5 kPa O2). We show that cells in culture require iron supplementation to activate the metalloprotein geNOps and demonstrate for the first time that cells adapted to physiological normoxia require significantly lower iron compared to cells adapted to hyperoxia. This study establishes an essential role for recapitulating oxygen levels in vivo and uncovers a previously unrecognized requirement for ferrous iron supplementation under standard cell culture conditions to achieve geNOps functionality.Integration Projects of Sabanci University ; Heart Research U.K. ; British Heart Foundation ; European Cooperation in Science and Technology (COST) ; King's Together Strategic Awar
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