The majority of offshore wind turbines are founded on large-diameter, open-ended steel monopiles. Monopiles must resist lateral loads and overturning moments because of environmental (wind and wave) actions, whereas vertical loads tend to be comparatively small. Recent developments in turbine sizes and increases in hub heights have resulted in pile diameters increasing rapidly, whereas the embedment length to diameter ratio (L/D) is reducing. Soil erosion around piles, termed scour, changes the soil strength and stiffness properties and affects the system's load resistance characteristics. In practice, design scour depths of up to 1.3D are routinely assumed during the turbine lifetime; however, the impact on monopiles with low L/D is not yet fully understood. In this article, centrifuge tests are performed to assess the effect of scour on the performance of piles with low L/D. In particular, the effect of combined loads, scour type (global, local), and depth are considered. A loading system is developed that enables application of realistic load eccentricity and combined vertical, horizontal, and moment loading at the seabed level. An instrumented 1.8-m-diameter pile with L/D = 5 is used. A friction-reducing ball-type connection is designed to transfer lateral loads to the pile without inducing any rotational pile-head constraint, which is associated with loading rigs in tests of this nature. Results suggest that vertical and lateral load interaction is minimal. Scour has a significant impact on the lateral load-bearing capacity and stiffness of the pile, leads to increases in bending moment magnitude along the pile shaft, and lowers the location of peak pile bending moment. The response varies with scour type, with global scour resulting in larger moments than local scour. The size of the local scour hole is found to have a significant impact on the pile response, suggesting that scour hole width should be explicitly considered in design.

@en

In this paper, we present a novel MEMS Pirani sensor with triple heat sinks which was designed to measure the pressure inside thin film, wafer level packages. The sensors are made in SOI (silicon on insulator) wafers leading to a very simple fabrication process. The use of relatively thick single crystal silicon for the in plane bridges result in structures with good mechanical properties as compared to alternative surface micromachining processes and reduces problems with buckling and sticking. Since, the proposed Pirani has three heat sinks, the area of heat loss through the ambient gas is greatly enlarged as compared to Pirani sensors with one or two heat sinks, without increasing the size of the sensor. Consequently, a Priani sensor of 336 µm in length has a pressure measurement range of 0.08-200 Torr. Alternative designs have shown measurement ranges varying between 0.02 and 500 Torr. This new type of Pirani sensor is small enough to be easily integrated in small volume wafer level packages.@en

In this paper, the gas dependence of the Q factor in MEMS resonators is investigated and verified by the measurements in different ambient gases, with pressures changing from vacuum to atmosphere. The experimental results agree favorably with the existing theoretical models. The findings in the work suggest that low molecular weight gasses can be used to enhance the Q factor without the need for external low pressure.@en

In this paper, outgassing of the thin film vacuum package is analyzed by integrated MEMS (Microelectromechanical system) resonator and RBS (Rutherford backscattering spectroscopy). Outgassing behavior of different thin film packaging materials is studied by exodiffusion experiments. It is demonstrated that a high temperature pre anneal will greatly reduce the outgassing but can not eliminate it.@en

In this paper, we will present a novel MEMS Pirani sensor with triple heat sinks. The sensors are made on SOI (Silicon On Insulator) wafers leading to a very simple process and good mechanical structures as compared to alternative surface micromachining processes. Moreover, the proposed Pirani has three heat sinks. The area of heat loss through the ambient gas is greatly enlarged as compared to Pirani sensors with one or dual heat sinks without increasing the dimension of the sensor. Consequently, the dynamic pressure range of the Pirani sensor will be enlarged. Keywords: Pirani; SOI; Triple; Heat sink; Pressure; Sensor@en

Failure analysis (FA) is a critical element in Integrated Circuit (IC) manufacturing. As IC advances and new materials are introduced in the semiconductor process, some conventional FA techniques cannot be applied. In this paper, we present a novel FA technique for IC packages with copper wire. It is a low cost and time efficient dry etching technique, where microwave induced plasma (MIP) is utilized to decapsulate the plastic encapsulated microcircuits components. The system does not require any vacuum and is capable to remove the molding compound on the top of the IC chip without destroying the structure on the chip or the wires. The experimental set-up to operate the plasma is described and the results of the experiments are shown to prove the feasibility and the efficiency of the proposed technique.@en