Isogeometric analysis applied to frictionless large deformation elastoplastic contact

This paper focuses on the application of isogeometric analysis to model frictionless large deformation contact between deformable bodies and rigid surfaces that may be represented by analytical functions. The contact constraints are satisfied exactly with the augmented Lagrangian method, and treated with a mortar-based approach combined with a simplified integration method to avoid segmentation of the contact surfaces. The spatial discretization of the deformable body is performed with NURBS and C0-continuous Lagrange polynomial elements. The numerical examples demonstrate that isogeometric surface discretization delivers more accurate and robust predictions of the response compared to Lagrange discretizations

Organizational Knowledge Transfer: Introducing A Multi-Level Perspective

Posten inneholder presentasjon og tilhørende artikkel presentert på Academy of Management Annual Meeting i 2010Research on organizational knowledge transfer is burgeoning, due to the critical role of external knowledge as a source of advantages for firms as well as public sector organizations. Our study investigates knowledge transfer in the context of a Norwegian benchmarking project in which a majority of the country‟s municipality organizations participated over a period of two years. The explicit purpose of the project was to encourage the project groups to learn from the experiences of their partner organizations. A field sample of 82 benchmarking groups and 274 individual municipality managers were examined to test antecedents to knowledge transfer in this setting. Specifically, the relationships between knowledge transfer and group autonomy, group intensity of effort, absorptive capacity and cognitive distance were hypothesized in the current study, and possible moderator effects from group autonomy were tested on an exploratory basis. Our study was deliberately conducted using a composite multi-level design, in order to test individual and group level relationships simultaneously. The study detected a positive relationship between group intensity, group autonomy and knowledge transfer as well as a negative relationship between individual cognitive distance and knowledge transfer

Millimeter-wave diode-grid phase shifters

Monolithic diode grids have been fabricated on 2-cm square gallium-arsenide wafers with 1600 Schottky-barrier varactor diodes. Shorted diodes are detected with a liquid-crystal technique, and the bad diodes are removed with an ultrasonic probe. A small-aperture reflectometer that uses wavefront division interference was developed to measure the reflection coefficient of the grids. A Phase shift of 70° with a 7-dB loss was obtained at 93 GHz when the bias on the diode grid was changed from -3 V to 1 V. A simple transmission-line grid model, together with the measured low-frequency parameters for the diodes, was shown to predict the measured performance over the entire capacitive bias range of the diodes, as well as over the complete reactive tuning range provided by a reflector behind the grid, and over a wide range of frequencies form 33 GHz to 141 GHz. This shows that the transmission-line model and the measured low-frequency diode parameters can be used to design an electronic beam-steering array and to predict its performance. An electronic beam-steering array made of a pair of grids using state-of-the-art diodes with 5-Ω series resistances would have a loss of 1.4 dB at 90 GHz

Social-Cognitive Outcomes of Teachers’ Engagement in Community of Practice : Evidence from Finnish Basic Schools

Denne posten inneholder Powerpoint presentasjon og artikkel presentert av Paulsen, Hjertø og Thiveräinen på UCEA konferansen i 2010

Millimeter-Wave Diode-Grid Frequency Doubler

Monolithic diode grid were fabricated on 2-cm^2 gallium-arsenide wafers in a proof-of-principle test of a quasi-optical varactor millimeter-wave frequency multiplier array concept. An equivalent circuit model based on a transmission-line analysis of plane wave illumination was applied to predict the array performance. The doubler experiments were performed under far-field illumination conditions. A second-harmonic conversion efficiency of 9.5% and output powers of 0.5 W were achieved at 66 GHz when the diode grid was pumped with a pulsed source at 33 GHz. This grid had 760 Schottky-barrier varactor diodes. The average series resistance was 27 Ω, the minimum capacitance was 18 fF at a reverse breakdown voltage of -3 V. The measurements indicate that the diode grid is a feasible device for generating watt-level powers at millimeter frequencies and that substantial improvement is possible by improving the diode breakdown voltage

Dealing with Tsunami Risk - A Case Study for Thailand

The December 26 2004 tsunami event devastated large areas along the coastlines of Indonesia, Thailand, Myanmar, Sri Lanka and India, and even some parts of the east African coastline. It is a great challenge to the authorities in the countries affected by the tsunami to deal with the future risk of tsunami events and how to rehabilitate the devastated areas under consideration of that risk. On initiative from the Norwegian Geotechnical Institute (NGI), a project has been initiated to help develop a rehabilitation strategy in Thailand, but it is also intended as serve as an example project for other countries in the region. The project is undertaken for the Department of Mineral Resources (DMR) under the Ministry of Natural Resources and the Environment in Thailand, and is undertaken by NGI in cooperation with CCOP. The project is fully financed by the Royal Norwegian Ministry of Foreign Affairs. The paper describes the various components of the project, including: 1. Identification of possible future seismic and tsunami-triggering dislocation scenarios, and their associated risk level. This will involve a detailed study of the plate tectonics in the region and earthquake statistics, including correlations between earthquake magnitude and possible dislocations causing tsunamis. 2. Analyses of possible tsunami inundation levels for the various seismic scenarios and their possible consequences. A first step will be to verify that available tsunami and inundation models can predict the observations in connection with the December 2004 event on both global and local levels. 3. Assessment of possible measures to reduce or eliminate the potential consequences of future tsunamis. That may include physical barriers, vertical land reclamation, strengthening of buildings/new building codes, and development of new urban and city plans with focus on establishing safe “islands” and escape routes and placement of critical functions in safe areas. 4. Propose overall and specific reconstruction and rehabilitation plans for three typical selected areas along the coast in Thailand. Such plans will have both a short term and long term perspective