11,659 research outputs found
An Experimental and Numerical Study of the Humidity Effect on the Stability of a Capacitive Ceramic Pressure Sensor
The effect of the humidity of the surrounding atmosphere on the characteristics of capacitive structures is a known problem for capacitive gas-pressure sensors. However, the use of a differential mode of operation can provide a good solution – only the manufacturing of the ceramic structures with the appropriate pairs of capacitive sensing elements remains a major challenge. In order to find a compromise solution, the effect of the humid atmosphere and the moisture on the exterior of an LTCC-based capacitive pressure sensor was inspected closely through experimental and numerical analyses of various situations
Commentary: The case for caution in predicting scientists’ future impact
We stress-test the career predictability model proposed by Acuna et al.
[Nature 489, 201-202 2012] by applying their model to a longitudinal career
data set of 100 Assistant professors in physics, two from each of the top 50
physics departments in the US. The Acuna model claims to predict h(t+\Delta t),
a scientist's h-index \Delta t years into the future, using a linear
combination of 5 cumulative career measures taken at career age t. Here we
investigate how the "predictability" depends on the aggregation of career data
across multiple age cohorts. We confirm that the Acuna model does a respectable
job of predicting h(t+\Delta t) up to roughly 6 years into the future when
aggregating all age cohorts together. However, when calculated using subsets of
specific age cohorts (e.g. using data for only t=3), we find that the model's
predictive power significantly decreases, especially when applied to early
career years. For young careers, the model does a much worse job of predicting
future impact, and hence, exposes a serious limitation. The limitation is
particularly concerning as early career decisions make up a significant
portion, if not the majority, of cases where quantitative approaches are likely
to be applied.Comment: 2 pages, 1 figur
Design of LTCC-based Ceramic Structure for Chemical Microreactor
The design of ceramic chemical microreactor for the production of hydrogen needed in portable polymer-electrolyte membrane (PEM) fuel cells is presented. The microreactor was developed for the steam reforming of liquid fuels with water into hydrogen. The complex three-dimensional ceramic structure of the microreactor includes evaporator(s), mixer(s), reformer and combustor. Low-temperature co-fired ceramic (LTCC) technology was used to fabricate the ceramic structures with buried cavities and channels, and thick-film technology was used to make electrical heaters, temperature sensors and pressure sensors. The final 3D ceramic structure consists of 45 LTCC tapes. The dimensions of the structure are 75 × 41 × 9 mm3 and the weight is about 73 g
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