Effect of Temperature on the Die Shear Strength of a Au-Sn SLID Bond

The effect of temperature on the die shear strength of a optimized Au-Sn solid–liquid interdiffusion SLID bond, a reliable high temperature die attach and interconnect technology, was investigated. The shear strength was greatly reduced with temperature from 140 MPa at room temperature to 20 MPa at 573 K (300 °C). This reduction was unexpected since the melting point of a Au-Sn SLID bond is 795 K (522 °C). Fractographic studies revealed a change in fracture mode with increasing temperatures. This work emphasizes the importance of performing bond strength quantification at the intended application temperature.     

Polarization properties of a nematic liquid-crystal spatial light modulator for phase modulation

The polarization properties of a nematic zero-twist liquid-crystal (NLC) spatial light modulator (SLM) were studied. A large ratio between the liquid-crystal (LC) layer thickness and the pixel pitch combined with spatial variations in the applied electric field causes fringing fields between pixels. Depending on the LC alignment, the electric field components within the LC layer can result in a twist deformation. The produced inhomogeneous optical anisotropy affects the polarization of light propagating through the device. We experimentally examined polarization effects in different diffraction orders for both binary and blazed phase gratings. Simulations of the LC deformation together with finite-difference time-domain simulations for the optical propagation were used to calculate the corresponding far-field intensities. It was demonstrated how rigorous simulations of the NLC SLM properties can be used to understand the polarization features of different diffraction orders.     

Major hazard risk indicators for monitoring of trends in the Norwegian offshore petroleum sector

The Petroleum Safety Authority Norway (PSA, formerly Norwegian Petroleum Directorate) took in 1999 the initiative to develop a method in order to assess trends and status for the risk levels in the Norwegian offshore petroleum industry. A method was developed, and a pilot study report was issued in April 2001, covering the period 1996–2000. Annual updates have been performed since then, and the latest report covers the period 1996–2004. The statistical approach is based on recording occurrence of near misses and relevant incidents, performance of barriers and results from risk assessments. Of similar importance is an evaluation of safety culture, motivation, communication and perceived risk. This is covered through the use of social science methods, such as questionnaire surveys and a number of interviews, audit and inspection reports as well as accident and incident investigations. There are also indicators for occupational accidents and occupational illness/-physical working environment factors.The focus is on the major hazard risk components for personnel staying on the offshore installations. An overview of the indicators used to illustrate these risk aspects is presented, followed by a discussion of the analytical approach used for these indicators. Results from the risk assessment for the Norwegian Continental Shelf in the period 1996–2004 are used throughout for illustration, and discussion of challenges.     

Biological availability of iron found in fish-meals

Samples of uncontaminated meals produced in the laboratory from capelin and mackerel were found to contain about 70 and 90 mg iron kg^?1, respectively. Commercially produced fish-meals were contaminated to a varying degree by iron from the processing equipment. The increased iron content in commercial meals may represent an important nutritional iron source. In experiments with chicks, the biological availability of the iron in fish-meals was found to depend on the total amount present. Compared with iron given as ferrous sulphate, the ‘fish-iron’ was found to be about 70% available, whereas the ‘contaminating iron’ derived from the processing equipment during production showed considerably lower availability, varying from 22 to 52%, depending on the factory.