Temperature dependence and long term behaviour of capillary-type helium reference leaks with gas reservoir

Vacuum ◽  
1990 ◽  
Vol 41 (7-9) ◽  
pp. 1863-1865 ◽  
Author(s):  
W. Große Bley
Keyword(s):  
Temperature Dependence ◽  
Gas Reservoir ◽  
Capillary Type

Pond and wetland treatment

2003 ◽  
Vol 48 (5) ◽  
pp. 1-8 ◽  
Author(s):  
R.H. Kadlec
Keyword(s):  
Temperature Dependence ◽  
Rate Constants ◽  
Cost Effective ◽  
Fecal Coliforms ◽  
First Order ◽  
Loading Rates ◽  
Wetland Treatment ◽  
Long Term Performance ◽  
Term Performance

Wetlands are in use as adjuncts to wastewater treatment lagoons at many north temperate locations. Performance data for 21 systems show median removals of 67, 61, 61, 48 and 99.8% for TSS, BOD, NH4-N, TP and fecal coliforms, respectively. Hydraulic loading rates range from 0.14 to 55 cm/d, areas from 0.02 to 200 ha, and latitudes from 30 to 54°N. Calibrations of first order models with temperature dependence show that rate constants vary from seasonal dependence at low loadings to temperature dependence at high loadings for ammonia. Phosphorus rate constants display seasonal, not temperature effects. BOD and TSS are not affected by season. Wetland rate constants are larger than those for lagoons for all constituents. The optimal winter operating strategy, if hydraulics allow, is partial storage during frozen months, coupled with winter use of the wetlands. The use of FWS wetlands for polishing lagoon effluents is cost effective when land availability is not drastically constrained. Many systems have been in operation long enough to demonstrate sustainable long-term performance. Infiltration beds are potentially a valuable addition to ponds and wetlands.

scholarly journals Summer ozone in the northern Front Range metropolitan area: weekend–weekday effects, temperature dependences, and the impact of drought

2017 ◽  
Vol 17 (11) ◽  
pp. 6517-6529 ◽  
Author(s):  
Andrew J. Abeleira ◽  
Delphine K. Farmer
Keyword(s):  
Temperature Dependence ◽  
Metropolitan Area ◽  
Ozone Production ◽  
Nox Emissions ◽  
Front Range ◽  
Temperature Dependent ◽  
Biogenic Voc ◽  
Temperature Dependences ◽  
The Impact

Abstract. Contrary to most regions in the US, ozone in the northern Front Range metropolitan area (NFRMA) of Colorado was either stagnant or increasing between 2000 and 2015, despite substantial reductions in NOx emissions. We used available long-term ozone and NOx data in the NFRMA to investigate these trends. Ozone increased from weekdays to weekends for a number of sites in the NFRMA with weekend reductions in NO2 at two sites in downtown Denver, indicating that the region was in a NOx-saturated ozone production regime. The stagnation and increases in ozone in the NFRMA are likely due to a combination of decreasing NOx emissions in a NOx-saturated environment and increased anthropogenic volatile organic compound (VOC) emissions in the NFRMA. Further investigation of the weekend–weekday effect showed that the region outside of the most heavily trafficked Denver area was transitioning to peak ozone production towards NOx-limited chemistry. This transition implies that continued NOx decreases will result in ozone being less sensitive to changes in either anthropogenic or biogenic VOC reactivity in the NFRMA. In contrast to anthropogenic VOCs, biogenic VOCs are unlikely to have increased in the NFRMA between 2000 and 2015, but are temperature dependent and likely vary by drought year. Ozone in the NFRMA has a temperature dependence, albeit smaller than many other US locations, consistent with biogenic VOC contributions to ozone production in the region. We show that while ozone increased with temperature in the NFRMA, which is consistent with a NOx-saturated regime coupled to temperature-dependent VOCs, this relationship is suppressed in drought years. We attribute this drought year suppression to decreased biogenic isoprene emissions due to long-term drought stress. Thus, while anthropogenic NOx and VOCs likely dominate ozone production regimes in the NFRMA, biogenic VOCs may also impact regional ozone and its temperature dependence.

scholarly journals Main Approaches to Cable Aging Management at Nuclear Power Plants in Ukraine

2019 ◽  
pp. 54-62
Author(s):  
T. Bilan ◽  
I. Rezvik ◽  
O. Sakhno ◽  
O. But ◽  
S. Bogdanov
Keyword(s):  
Service Life ◽  
Temperature Dependence ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Operating Temperature ◽  
Operating Conditions ◽  
Insulation Material ◽  
Term Operation

The mechanisms of cable ageing at nuclear power plants (NPPs) mainly depending on the insulation material, as well as the damaging factors affecting cables that are determined by the operating conditions are considered in the paper. The main and additional mechanisms of aging resulting from the effects of damaging factors are provided. The paper presents the main methods of cable aging management: determining the actual service life and testing using field methods and other means. The basic principles for the arrangement of cable aging management at Ukrainian NPPs, as well as the methods used to investigate the technical condition of cables, are presented. A list of mandatory lists has been defined when performing activities on cable aging management. A methodology is described for lifetime extension of cables, and conditions for extending the service life of cables that are in service are provided. A number of methods of testing cables for aging management are considered: visual inspection of insulation and measurement of crack size, discoloration, etc.; insulation hardness test; insulation chemical analysis; electrical insulation tests; tensile strength measurement; measurement of elongation at break; measurements of dielectric loss at low frequency or sweep frequency; testing by dynamic reflectometry method; AC and DC current impedance measurements. The paper presents results of separate laboratory studies for selected 1 kV representative power cables with PVC insulation of SUNPP-1, ZNPP-1 and KhNPP-2 conducted within Ukrainian NPP long-term operation, which included a stage of laboratory examination and examination of cable samples in operating conditions. The following results were obtained: dependence of VVGng 4x6 cable lifetime on operating temperature; dependence of AVVG cable lifetime on operating temperature; dependence of AVVG (a) cable lifetime on operating temperature. There are possibilities and conditions under which the use of cables within long-term operation is permissible.

scholarly journals High Reliability Evaluation and Lifetime Prediction of 50 GHz Athermal AWG Module

2021 ◽  
Vol 11 (23) ◽  
pp. 11107
Author(s):  
Kwang-Su Yun ◽  
Chong-Hee Yu ◽  
Kwon-Seob Lim ◽  
Young-Sic Kim ◽  
Insu Jeon
Keyword(s):  
Temperature Dependence ◽  
Insertion Loss ◽  
High Reliability ◽  
Accelerated Life Testing ◽  
Center Wavelength ◽  
Accelerated Life ◽  
Outdoor Environments ◽  
Indoor And Outdoor Environments ◽  
Nm Range

A 96-channel (50 GHz-spacing) athermal AWG has been developed. It has a wide operating range due to reduced temperature dependence than conventional AWG. The temperature dependence of the center wavelength of the developed module satisfied the ±0.05 nm range in all channels in the temperature range of −40 °C to 85 °C, and the insertion loss variation was also less than ±0.5 dB. As a result of validating its reliability through tests based on Telcordia-GR-1209 and GR-1221, the temperature dependence of the center wavelength satisfied the ±0.022 nm range, and the insertion loss variation was also less than ±0.2 dB. Accelerated life testing showed an expected service life of over 36.7 years, ensuring long-term safety of communication quality in harsh indoor and outdoor environments.

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