The impact of temperature and humidity conditions on surface insulation resistance values for various fluxes

Abstract The National Centers for Environmental Prediction regional spectral model and mesoscale spectral model (NCEP RSM/MSM) use a spectral computation on perturbation. The perturbation is defined as a deviation between RSM/MSM forecast value and their outer model or analysis value on model sigma-coordinate surfaces. The horizontal diffusion used in the models applies perturbation diffusion in spectral space on model sigma-coordinate surfaces. However, because of the large difference between RSM/MSM and their outer model or analysis terrains, the perturbation on sigma surfaces could be large over steep mountain areas as horizontal resolution increases. This large perturbation could introduce systematical error due to artificial vertical mixing from horizontal diffusion on sigma surface for variables with strong vertical stratification, such as temperature and humidity. This nonnegligible error would eventually ruin the forecast and simulation results over mountain areas in high-resolution modeling. To avoid the erroneous vertical mixing on the systematic perturbation, a coordinate transformation is applied in deriving a horizontal diffusion on pressure surface from the variables provided on terrain-following sigma coordinates. Three cases are selected to illustrate the impact of the horizontal diffusion on pressure surfaces, which reduces or eliminates numerical errors of mesoscale modeling over mountain areas. These cases address concerns from all aspects, including unstable and stable synoptic conditions, moist and dry atmospheric settings, weather and climate integrations, hydrostatic and nonhydrostatic modeling, and island and continental orography. After implementing the horizontal diffusion on pressure surfaces for temperature and humidity, the results show better rainfall and flow pattern simulations when compared to observations. Horizontal diffusion corrects the warming, moistening, excessive rainfall, and convergent flow patterns around high mountains under unstable and moist synoptic conditions and corrects the cooling, drying, and divergent flow patterns under stable and dry synoptic settings.

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Analysis of surface insulation resistance related failures in electronics by circuit simulation

Circuit World ◽

10.1108/cw-09-2016-0040 ◽

2017 ◽

Vol 43 (2) ◽

pp. 45-55 ◽

Cited By ~ 2

Author(s):

Vadimas Verdingovas ◽

Salil Joshy ◽

Morten Stendahl Jellesen ◽

Rajan Ambat

Keyword(s):

Printed Circuit Board ◽

Electronic Device ◽

Early Stage ◽

Circuit Simulation ◽

Circuit Board ◽

Insulation Resistance ◽

Electronic Circuits ◽

Content Type ◽

Printed Circuit ◽

Surface Insulation Resistance

Purpose The purpose of this study is to show that the humidity levels for surface insulation resistance (SIR)-related failures are dependent on the type of activators used in no-clean flux systems and to demonstrate the possibility of simulating the effects of humidity and contamination on printed circuit board components and sensitive parts if typical SIR data connected to a particular climatic condition are available. This is shown on representative components and typical circuits. Design/methodology/approach A range of SIR values obtained on SIR patterns with 1,476 squares was used as input data for the circuit analysis. The SIR data were compared to the surface resistance values observable on a real device printed circuit board assembly. SIR issues at the component and circuit levels were analysed on the basis of parasitic circuit effects owing to the formation of a water layer as an electrical conduction medium. Findings This paper provides a summary of the effects of contamination with various weak organic acids representing the active components in no-clean solder flux residue, and demonstrates the effect of humidity and contamination on the possible malfunctions and errors in electronic circuits. The effect of contamination and humidity is expressed as drift from the nominal resistance values of the resistors, self-discharge of the capacitors and the errors in the circuits due to parasitic leakage currents (reduction of SIR). Practical/implications The methodology of the analysis of the circuits using a range of empirical leakage resistance values combined with the knowledge of the humidity and contamination profile of the electronics can be used for the robust design of a device, which is also important for electronic products relying on low current consumption for long battery lifetime. Originality/value Examples provide a basic link between the combined effect of humidity and contamination and the performance of electronic circuits. The methodology shown provides the possibility of addressing the climatic reliability of an electronic device at the early stage of device design by using typical SIR data representing the possible climate exposure.

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INFLUENCE OF THE TEMPERATURE AND HUMIDITY REGIME OF BURIED VOLUMES ON THE PRESERVATION OF ARCHITECTURAL MONUMENTS WITH MONUMENTAL PAINTINGS ON THE EXAMPLE OF THE TRANSFIGURATION CHURCH IN POLOTSK

Building and reconstruction ◽

10.33979/2073-7416-2021-98-6-43-49 ◽

2021 ◽

Vol 98 (6) ◽

pp. 43-49

Author(s):

V.B. DOROKHOV ◽

◽

N.YU. PINTELIN ◽

D.YU. ZHELDAKOV ◽

◽

...

Keyword(s):

Wide Range ◽

Temperature And Humidity ◽

The Impact

The heat and humidity regime of the buried parts can be essential, and sometimes crucial, for the normalization of the microclimate of the entire monument. The experience of thermophysical studies in church architectural monuments shows a wide range of factors that determine the impact of the temperature and humidity regime of the buried volumes on the formation of conditions for the preservation of the monument as a whole. Currently, the Climate Laboratory of Museums and Architectural Monuments of GOSNIIR conducts research on this problem in order to create a methodology for studying and normalizing the heat and humidity regime of the aboveground and underground parts of the building as a whole to develop design and technological approaches to optimizing the conditions for the preservation of the monument. The article considers a practical example of providing heat and humidity conditions for the preservation of a monument with monumental painting.

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The impact of thermal comfort in the perceived level of service and energy costs of three Brazilian airports

Journal of Transport Literature ◽

10.1590/s2238-10312013000200010 ◽

2013 ◽

Vol 7 (2) ◽

pp. 192-206 ◽

Cited By ~ 12

Author(s):

Jacqueline Elhage Ramis ◽

Emmanuel Antonio dos Santos

Keyword(s):

Thermal Comfort ◽

Air Conditioning ◽

International Standards ◽

Combined System ◽

Service Levels ◽

Transportation Demand ◽

Temperature And Humidity ◽

Air Conditioning Systems ◽

Air Circulation ◽

The Impact

To evaluate airports' current thermal comfort temperature and humidity were registered in three main Brazilian international airports, other variables were local region climate characteristics and the constructive types of passenger terminal buildings. The Brazilian air transportation demand has considerably grown over the last decade, with some airports reaching their capacity. Thermal discomfort may be a key driver of passenger perceptions of airport service levels, specially under capacity overload situations. Therefore, to achieve airport thermal comfort within this new scenario, and with the imminent and future expansions of the airport system, certainly put extra work on the existing air conditioning systems, consequently increasing energy consumption and its associated costs. Collected temperature and humidity from each study case subsided the data for the psychrometric charts. The evidences showed temperatures below the international standards requirements for thermal comfort levels. These charts also indicated that adequate building types with natural air circulation, provides the best levels of thermal comfort. Results suggest the importance of considering the implementation of a combined system using artificial and natural air conditioning in the planning of future expansions.

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The impact of temperature and humidity measures on influenza A (H7N9) outbreaks—evidence from China

International Journal of Infectious Diseases ◽

10.1016/j.ijid.2014.11.010 ◽

2015 ◽

Vol 30 ◽

pp. 122-124 ◽

Cited By ~ 21

Author(s):

Yi Zhang ◽

Cindy Feng ◽

Chunna Ma ◽

Peng Yang ◽

Song Tang ◽

...

Keyword(s):

Influenza A ◽

Temperature And Humidity ◽

The Impact

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The Influence of Temperature and Humidity on the ABS Contaminations

2014 Conference on Information Storage and Processing Systems ◽

10.1115/isps2014-6981 ◽

2014 ◽

Cited By ~ 2

Author(s):

Fuhao Cui ◽

Jinhong Hu ◽

Yue Peng ◽

Hui Li ◽

Shengnan Shen ◽

...

Keyword(s):

Shear Stress ◽

Flow Pattern ◽

Air Flow ◽

Disk Drive ◽

Flying Height ◽

Flow Shear ◽

Slip Boundary ◽

Temperature And Humidity ◽

Flow Shear Stress ◽

The Impact

In order to increase the areal recording density of hard disk drive beyond 1 Tb/in2, the flying height has to be reduced to several nanometers. At such a low flying height, particles and lube contaminations, which could lead to a transient vibration and flying height modulation in a hard disk drive, are becoming more and more serious. In this work, it studies the influence of temperature and humidity on the air flow pattern, velocity and shear stress distribution on the air bearing surface (ABS) of slider using a self-developed simulator. It first solves the generalized steady state Reynolds equation with slip boundary conditions. Then it solves the reduced Navier-Stokes (N-S) equation with slip boundary conditions to get the air velocity distribution, i.e., identify the air flow pattern on the ABS. The stagnation lines and areas of air flow are calculated to judge the contamination area. On the other hand, it calculates the air shear stress distribution on the ABS since the air shear stress is the main driving force for the lubricant and particles migration and contaminations. After that, the impact of the temperature and humidity on the air flow pattern is analyzed by applying the Sutherland equation and mixed gas viscosity calculation equation. The simulation results indicate that the impact of temperature and humidity on the air flow pattern is un-conspicuous. However, the peak velocity of the air flow, which contains no vapor, reduces almost 10%, and the peak air flow shear stress increases less than 1.5%, with the increase of operational temperature from 298.15 K to 343.15 K. In addition, the peak velocity of the air flow increasing almost 4%, and the peak air flow shear stress keeps almost same, with the increase of the operational mole fraction of vapor from 5% to 15%.

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Field measurements of windbreak effects on airflow, turbulent exchanges and microclimates

Australian Journal of Experimental Agriculture ◽

10.1071/ea02004 ◽

2002 ◽

Vol 42 (6) ◽

pp. 665 ◽

Cited By ~ 19

Author(s):

H. A. Cleugh

Keyword(s):

Wind Speed ◽

Water Vapour ◽

Incident Angle ◽

Surface Wind ◽

Field Measurements ◽

Experimental Program ◽

Near Surface ◽

Speed Reduction ◽

Temperature And Humidity ◽

The Impact

While there has been considerable research into airflow around windbreaks, the interaction of this airflow with the exchanges of heat and water vapour has received far less attention. Yet, the effects of windbreaks on microclimates, water use and agricultural productivity depend, in part, on this interaction. A field and wind tunnel experimental program was conducted to quantify the effects of windbreaks on microclimates and evaporation fluxes. This paper describes the field measurements, which were conducted over a 6-week period at a tree windbreak site located in undulating terrain in south-east Australia. The expected features of airflow around porous windbreaks were observed despite the less than ideal nature of the site. As predicted from theory, the air temperature and humidity were elevated, by day, in the quiet zone and the location of the peak increase in temperature and humidity coincided with the location of the minimum wind speed. However, this increase in temperature and humidity was small in size and restricted to the zone within 10 windbreak heights (H) of the windbreak. This pattern contrasts with that for the near surface wind speeds, which were reduced by up to 80% in a sheltered zone that extended from 5 H upwind to over 25 H downwind of the windbreak. Similar differences were found between the turbulent scalar (heat, water vapour) and velocity terms. While both are reduced in the quiet zone, the turbulent scalar terms near the surface were substantially enhanced at the location where the wake zone begins. Here the mean wind speed is reduced by 50% and the turbulent velocity terms return to their upwind values. Wind speed reductions varied linearly with [cos (90 – α)], where α is the incident angle of the wind, for sites located 6 H downwind. This means that the spatial pattern of wind speed reduction applies to all wind directions, provided that distance downwind is expressed in terms of streamwise distance. However, shelter in the near-break region is slightly increased as the wind blows more obliquely towards the windbreak. The atmospheric demand in the quiet zone was reduced when the humidity of the upwind air was low. In such conditions, windbreaks can 'protect' growing crops from the impact of dry air with high atmospheric demand. The corollary is that in humid conditions, the atmospheric demand in the quiet zone can be increased as a result of shelter.

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