The Application of PEEK to the Packaging of Implantable Electronic Devices: Water Permeation Calculation Method and Maximum Achievable Lifetime with Desiccant

2013 ◽  
Vol 10 (1) ◽  
pp. 15-22 ◽  
Author(s):  
Nathaniel Dahan ◽  
Nick Donaldson ◽  
Stephen Taylor ◽  
Nuno Sereno
Keyword(s):  
Water Vapor ◽  
Relative Humidity ◽  
Calculation Method ◽  
Electronic Devices ◽  
Medical Implants ◽  
Permeable Material ◽  
Short Term ◽  
Water Permeation ◽  
Internal Relative Humidity ◽  
Device Lifetime

When packaging electronics to protect from the effects of water vapor, it is essential to be able to predict how moisture will permeate the enclosure. In the context of short term medical implants, for instance, packages made of a permeable material such as a polymer may be acceptable, provided calculations and tests show that low internal relative humidity (RH) is guaranteed for the required device lifetime. A method is presented to evaluate the permeation of water vapor into a package with desiccant, and tests are described to evaluate the validity of the model experimentally. Achievable lifetimes for PEEK packages with silica gel are investigated.

The Application of PEEK to Implantable Electronic Devices Packaging: Water Permeation Calculation Method and Maximum Lifetime with Desiccant

2012 ◽  
Vol 2012 (1) ◽  
pp. 000340-000350
Author(s):  
Nathaniel Dahan ◽  
Nick Donaldson ◽  
Stephen Taylor ◽  
Nuno Sereno
Keyword(s):  
Relative Humidity ◽  
Water Vapour ◽  
Electronic Devices ◽  
Medical Implants ◽  
Permeable Material ◽  
Short Term ◽  
Water Permeation ◽  
Maximum Lifetime ◽  
Internal Relative Humidity ◽  
Device Lifetime

When packaging electronics to protect from the effects of water vapour, it is essential to be able to predict how moisture will permeate the enclosure. In the context of short term medical implants for instance, packages made of a ‘permeable’ material such as a polymer may be acceptable, provided calculations and tests show that low internal relative humidity is guaranteed for the required device lifetime. This paper presents a method to evaluate the water vapour permeation into a package which has walls or elements of different thicknesses or properties. Tests are described to evaluate the validity of this model experimentally. The method is adapted for the use of desiccant and achievable lifetimes for PEEK packages with silica gel are investigated.

The Effect of Water Vapor on the Corrosion of Carbon Steel at 65°c

1995 ◽  
Vol 412 ◽  
Author(s):  
Gregory E. Gdowski ◽  
John C. Estill
Keyword(s):  
Water Vapor ◽  
Carbon Steel ◽  
Relative Humidity ◽  
Electrochemical Corrosion ◽  
Short Term ◽  
Effect Of Water ◽  
Dry Oxidation ◽  
Critical Relative Humidity

AbstractAISI 1020 carbon steel was exposed to air at various relative humidities at 65°C. A “critical relative humidity” (CRH) of 75–85% was determined. The CRH is the transitional relative humidity where oxidation/corrosion changes from dry oxidation to aqueous film electrochemical corrosion. Short term testing suggests that aqueous film electrochemical corrosion results in the formation of an inner oxide of Fe3O4, and an outer oxide of a powdery Fe2O3 and/or Fe2O3·xH2O.

scholarly journals HGPT2: An ERA5-Based Global Model to Estimate Relative Humidity

2021 ◽  
Vol 13 (11) ◽  
pp. 2179
Author(s):  
Pedro Mateus ◽  
Virgílio B. Mendes ◽  
Sandra M. Plecha
Keyword(s):  
Water Vapor ◽  
Relative Humidity ◽  
Real Time ◽  
Prediction Models ◽  
Weather Prediction ◽  
Precipitable Water ◽  
Precipitable Water Vapor ◽  
Global Navigation Satellite Systems ◽  
International Gnss Service ◽  
Weighted Mean Temperature

The neutral atmospheric delay is one of the major error sources in Space Geodesy techniques such as Global Navigation Satellite Systems (GNSS), and its modeling for high accuracy applications can be challenging. Improving the modeling of the atmospheric delays (hydrostatic and non-hydrostatic) also leads to a more accurate and precise precipitable water vapor estimation (PWV), mostly in real-time applications, where models play an important role, since numerical weather prediction models cannot be used for real-time processing or forecasting. This study developed an improved version of the Hourly Global Pressure and Temperature (HGPT) model, the HGPT2. It is based on 20 years of ERA5 reanalysis data at full spatial (0.25° × 0.25°) and temporal resolution (1-h). Apart from surface air temperature, surface pressure, zenith hydrostatic delay, and weighted mean temperature, the updated model also provides information regarding the relative humidity, zenith non-hydrostatic delay, and precipitable water vapor. The HGPT2 is based on the time-segmentation concept and uses the annual, semi-annual, and quarterly periodicities to calculate the relative humidity anywhere on the Earth’s surface. Data from 282 moisture sensors located close to GNSS stations during 1 year (2020) were used to assess the model coefficients. The HGPT2 meteorological parameters were used to process 35 GNSS sites belonging to the International GNSS Service (IGS) using the GAMIT/GLOBK software package. Results show a decreased root-mean-square error (RMSE) and bias values relative to the most used zenith delay models, with a significant impact on the height component. The HGPT2 was developed to be applied in the most diverse areas that can significantly benefit from an ERA5 full-resolution model.

scholarly journals Implementation of a 3-D-Var system for atmospheric profiling data assimilation into the RAMS model: initial results

2013 ◽  
Vol 6 (2) ◽  
pp. 3581-3610
Author(s):  
S. Federico
Keyword(s):  
Relative Humidity ◽  
Data Assimilation ◽  
Initial Conditions ◽  
Weather Prediction ◽  
Wind Profiler ◽  
Short Term ◽  
Recursive Filters ◽  
Data Assimilation System ◽  
Rams Model ◽  
Assimilation System

Abstract. This paper presents the current status of development of a three-dimensional variational data assimilation system. The system can be used with different numerical weather prediction models, but it is mainly designed to be coupled with the Regional Atmospheric Modelling System (RAMS). Analyses are given for the following parameters: zonal and meridional wind components, temperature, relative humidity, and geopotential height. Important features of the data assimilation system are the use of incremental formulation of the cost-function, and the use of an analysis space represented by recursive filters and eigenmodes of the vertical background error matrix. This matrix and the length-scale of the recursive filters are estimated by the National Meteorological Center (NMC) method. The data assimilation and forecasting system is applied to the real context of atmospheric profiling data assimilation, and in particular to the short-term wind prediction. The analyses are produced at 20 km horizontal resolution over central Europe and extend over the whole troposphere. Assimilated data are vertical soundings of wind, temperature, and relative humidity from radiosondes, and wind measurements of the European wind profiler network. Results show the validity of the analysis solutions because they are closer to the observations (lower RMSE) compared to the background (higher RMSE), and the differences of the RMSEs are consistent with the data assimilation settings. To quantify the impact of improved initial conditions on the short-term forecast, the analyses are used as initial conditions of a three-hours forecast of the RAMS model. In particular two sets of forecasts are produced: (a) the first uses the ECMWF analysis/forecast cycle as initial and boundary conditions; (b) the second uses the analyses produced by the 3-D-Var scheme as initial conditions, then is driven by the ECMWF forecast. The improvement is quantified by considering the horizontal components of the wind, which are measured at a-synoptic times by the European wind profiler network. The results show that the RMSE is effectively reduced at the short range (1–2 h). The results are in agreement with the set-up of the numerical experiment.

scholarly journals Cooling Performance of Heat Sinks Used in Electronic Devices

2018 ◽  
Vol 171 ◽  
pp. 02003
Author(s):  
Ibrahim Mjallal ◽  
Hussein Farhat ◽  
Mohammad Hammoud ◽  
Samer Ali ◽  
Ali AL Shaer ◽  
...  
Keyword(s):  
Heat Sink ◽  
Electronic Devices ◽  
Heat Fluxes ◽  
Electronic Cooling ◽  
Heat Sinks ◽  
Passive Cooling ◽  
Short Term ◽  
Cooling Systems ◽  
Thermal Output ◽  
Electrical Devices

Existing passive cooling solutions limit the short-term thermal output of systems, thereby either limiting instantaneous performance or requiring active cooling solutions. As the temperature of the electronic devices increases, their failure rate increases. That’s why electrical devices should be cooled. Conventional electronic cooling systems usually consist of a metal heat sink coupled to a fan. This paper compares the heat distribution on a heat sink relative to different heat fluxes produced by electronic chips. The benefit of adding a fan is also investigated when high levels of heat generation are expected.

scholarly journals Deuterium excess in marine water vapor: Dependency on relative humidity and surface wind speed during evaporation

2014 ◽  
Vol 119 (2) ◽  
pp. 584-593 ◽  
Author(s):  
Marion Benetti ◽  
Gilles Reverdin ◽  
Catherine Pierre ◽  
Liliane Merlivat ◽  
Camille Risi ◽  
...  
Keyword(s):  
Water Vapor ◽  
Wind Speed ◽  
Relative Humidity ◽  
Surface Wind ◽  
Surface Wind Speed ◽  
Marine Water ◽  
Deuterium Excess

scholarly journals Impact of Lightning Data Assimilation on Forecasts of a Leeward Slope Precipitation Event in the Western Margin of the Junggar Basin

2021 ◽  
Vol 13 (18) ◽  
pp. 3584
Author(s):  
Peng Liu ◽  
Yi Yang ◽  
Yu Xin ◽  
Chenghai Wang
Keyword(s):  
Water Vapor ◽  
Data Assimilation ◽  
Three Dimensional ◽  
Junggar Basin ◽  
Precipitation Event ◽  
Short Term ◽  
Western Margin ◽  
Precipitation Prediction ◽  
Analysis Experiment ◽  
Short Term Forecasting

A moderate precipitation event occurring in northern Xinjiang, a region with a continental climate with little rainfall, and in leeward slope areas influenced by topography is important but rarely studied. In this study, the performance of lightning data assimilation is evaluated in the short-term forecasting of a moderate precipitation event along the western margin of the Junggar Basin and eastern Jayer Mountain. Pseudo-water vapor observations driven by lightning data are assimilated in both single and cycling analysis experiments of the Weather Research and Forecast (WRF) three-dimensional variational (3DVAR) system. Lightning data assimilation yields a larger increment in the relative humidity in the analysis field at the observed lightning locations, and the largest increment is obtained in the cycling analysis experiment. Due to the increase in water vapor content in the analysis field, more suitable thermal and dynamic conditions for moderate precipitation are obtained on the leeward slope, and the ice-phase and raindrop particle contents increase in the forecast field. Lightning data assimilation significantly improves the short-term leeward slope moderate precipitation prediction along the western margin of the Junggar Basin and provides the best forecast skill in cycling analysis experiments.

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