365 research outputs found
Determinants for students perceived potential of BIM use
Newly graduated students are shown to constitute an important source of innovation withinthe architectural, engineering and construction (AEC) industry. In relation to digital technologies likeBIM (Building Information Modelling) that is claimed to have a potential to transform the industry,newly graduated students may play a vital role in innovating with BIM. The paper aims to exploredeterminants for students perceived potential of BIM use (PPBU) and the role of the educationalbackground. The aim will be achieved by analysing the results from a survey conducted among thirdand fourth-year students in construction and civil engineering in Hong Kong, Sweden, and Thailand (n= 194). When the different groups are compared Swedish and Thai students perceive a significant higherPPBU than Hong Kong students. In a step-wise multiple regression analysis five predictors for PPBUwere identified for Thai respectively Swedish students, and one predictor was identified for Hong Kongstudents. It is concluded that in the contemporary BIM-discourse it is claimed that BIM can/shouldtransform the industry, and BIM is even seen as a disruptive technology, and newly graduated studentswill contribute to (digitally driven) innovation. However, from the predictors of PPBU, the question canraised if the awareness of the need for structural changes is lacking in the education, if students later intheir working life should contribute to a BIM-induced transformation of the industry
Tværfaglig undervisning i folkeskolens naturfag
Formålet med denne artikel er at give en introduktion til tværfaglighed og didaktiske ele-menter i en tværfaglighedsdidaktik i folkeskolens naturfag. Artiklen starter med at definere centrale begreber omkring tværfaglighed og begrundelser for tværfaglig undervisning. Herefter redegøres for studier af elevers læringsudbytte i tværfaglig undervisning og læreres holdning til samt udfordringer ved at undervise tværfagligt. Artiklen afsluttes med en redegørelse af hvilke konsekvenser det øgede fokus på tværfaglighed har for undervisningspraksis, og hvilke opmærksomhedspunkter undervisnin-gen kan antage for at imødekomme udfordringer omkring tværfaglig undervisning
Low-temperature positron-lifetime studies of proton-irradiated silicon
The positron-lifetime technique has been used to identify defects created in high-purity single-crystal silicon by irradiation with 12-MeV protons at 15 K, and the evolution of the defects has been studied by subsequent annealings between 20 and 650 K. Two clear annealing steps were seen in the samples, the first starting at 100 K and the other at 400 K. The first is suggested to be a result of the migration of free, negatively charged monovacancies, and the second is connected to the annealing of some vacancy-impurity complexes, probably negatively charged vacancy-oxygen pairs. The specific trapping rate of positrons to both of these negatively charged monovacancy-type defects has been found to have a clear T-0.5 dependence. The positron lifetime in perfect Si is measured to be 217±1 ps, and the monovacancy lifetime is found to be 275±5 ps. Also the negatively charged vacancy-oxygen complexes were found, both experimentally and theoretically, to give rise to a positron lifetime of about 275 ps
Exploring the transferability of large supramolecular assemblies to the vacuum-solid interface
We present an interplay of high-resolution scanning tunneling microscopy imaging and the corresponding theoretical calculations based on elastic scattering quantum chemistry techniques of the adsorption of a gold-functionalized rosette assembly and its building blocks on a Au(111) surface with the goal of exploring how to fabricate functional 3-D molecular nanostructures on surfaces. The supramolecular rosette assembly stabilized by multiple hydrogen bonds has been sublimed onto the Au(111) surface under ultra-high vacuum conditions; the resulting surface nanostructures are distinctly different from those formed by the individual molecular building blocks of the rosette assembly, suggesting that the assembly itself can be transferred intact to the surface by in situ thermal sublimation. This unanticipated result will open up new perspectives for growth of complex 3-D supramolecular nanostructures at the vacuum-solid interface
Epitaxial growth of Cu on Cu(001): experiments and simulations
A quantitative comparison between experimental and Monte Carlo simulation
results for the epitaxial growth of Cu/Cu(001) in the submonolayer regime is
presented. The simulations take into account a complete set of hopping
processes whose activation energies are derived from semi-empirical
calculations using the embedded-atom method. The island separation is measured
as a function of the incoming flux and the temperature. A good quantitative
agreement between the experiment and simulation is found for the island
separation, the activation energies for the dominant processes, and the
exponents that characterize the growth. The simulation results are then
analyzed at lower coverages, which are not accessible experimentally, providing
good agreement with theoretical predictions as well.Comment: Latex document. 7 pages. 3 embedded figures in separate PS files. One
bbl fil
Finite-Size and surface effects in maghemite nanoparticles: Monte Carlo simulations
Finite-size and surface effects in fine particle systems are investigated by
Monte Carlo simulation of a model of a -FeO (maghemite) single
particle. Periodic boundary conditions have been used to simulate the bulk
properties and the results compared with those for a spherical shaped particle
with free boundaries to evidence the role played by the surface on the
anomalous magnetic properties displayed by these systems at low temperatures.
Several outcomes of the model are in qualitative agreement with the
experimental findings. A reduction of the magnetic ordering temperature,
spontaneous magnetization, and coercive field is observed as the particle size
is decreased. Moreover, the hysteresis loops become elongated with high values
of the differential susceptibility, resembling those from frustrated or
disordered systems. These facts are consequence of the formation of a surface
layer with higher degree of magnetic disorder than the core, which, for small
sizes, dominates the magnetization processes of the particle. However, in
contradiction with the assumptions of some authors, our model does not predict
the freezing of the surface layer into a spin-glass-like state. The results
indicate that magnetic disorder at the surface simply facilitates the thermal
demagnetization of the particle at zero field, while the magnetization is
increased at moderate fields, since surface disorder diminishes ferrimagnetic
correlations within the particle. The change in shape of the hysteresis loops
with the particle size demonstrates that the reversal mode is strongly
influenced by the reduced atomic coordination and disorder at the surface.Comment: Twocolumn RevTex format. 19 pages, 15 Figures included. Submitted to
Phys. Rev.
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