5,994 research outputs found
Pre-posterior analysis of inspections incorporating degradation of concrete structures
The framework of pre-posterior decision analysis has a large potential as a decision support tool in structural
engineering. It seems ideally suited to tackle problems related to determining the value of Structural Health
Monitoring and is commonly applied in inspection and maintenance planning. However, the application of this
methodology for integrated life-cycle cost decision making related to monitoring of time-dependent and
spatial degradation phenomena in concrete structures, needs further investigation. In this work, the timedependent
and spatial degradation phenomena will be coupled to the pre-posterior decision making approach
and applied on concrete beams under bending, subjected to corrosion of the reinforcement. A framework is
set up to determine the value of information of inspections enabling adequate decision-making. The
methodology incorporates Bayesian updating based on the uncertain inspection outcomes. The framework
will be illustrated by application on a simply supported reinforced concrete beam
Parents’ and Teachers’ Opinions about the School Food Policy in Belgian Flemish Nursery Schools
The partnership of parents, teachers, and schools is necessary to develop effective school food interventions. To gather parents' and teachers' opinions and perceptions about the school food policy, 884 parents and 70 teachers of preschoolers completed a questionnaire. School food policy is an issue of importance for parents and teachers: the majority agrees that schools should restrict the availability of snacks and soft drinks; however, to replace fruit juice and sugared milk drinks with sugarless alternatives will take special effort. Fruit is not always available at school, although parents would appreciate it. Parents of lower educational level are in general more permissive
Atomic layer deposition of aluminum phosphate based on the plasma polymerization of trimethyl phosphate
Aluminum phosphate thin films were deposited by plasma-assisted atomic layer deposition (ALD) using a sequence of trimethyl phosphate (TMP, Me3PO4) plasma, O-2 plasma, and trimethylaluminum (TMA, Me3Al) exposures. In situ characterization was performed, including spectroscopic ellipsometry, optical emission spectroscopy, mass spectrometry and FTIR. In the investigated temperature region between 50 and 320 degrees C, nucleation delays were absent and linear growth was observed, with the growth per cycle (GPC) being strongly dependent on temperature. The plasma polymerization of TMP was found to play an important role in this process, resulting in CVD-like behavior at low temperatures and ALD-like behavior at high temperatures. Films grown at 320 degrees C had a GPC value of 0.37 nm/cycle and consisted of amorphous aluminum pyrophosphate (Al4P6O21). They could be crystallized to triclinic AlPO4 (tridymite) by annealing to 900 degrees C, as evidenced by high-temperature XRD measurements. The use of a TMP plasma might open up the possibility of depositing many other metal phosphates by combining it with appropriate organometallic precursors
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