scholarly journals Field Study of Hygrothermal Performance of Cross‐Laminated Timber Wall Assemblies with Built‐In Moisture

2021 ◽  
Author(s):  
Victoria Ruth McClung
Keyword(s):  
North America ◽  
Seismic Performance ◽  
Field Data ◽  
Cross Laminated Timber ◽  
Hygrothermal Simulation ◽  
Potential Market ◽  
Hygrothermal Performance ◽  
Drying Behaviour ◽  
The Given

Cross-laminated timber (CLT) panels have potential market in North America for building mid-rise structures due to their good structural and seismic performance, lightweight, and prefabricated nature. However, to ensure long-term durability, the hygrothermal performance of CLT wall assemblies needs to be evaluated in terms of drying and wetting potential before their widespread adoption in North America. A test wall was constructed with initially wetted CLT panels, and monitored over a year. The drying behaviour of the panels was analysed, and results were compared to hygrothermal simulations. It was found from the field data that no tested wall assemblies in the given climate prevented the panels from drying in enough time to prevent decay initiation. The hygrothermal simulation program is capable of predicting general trends, and can predict if a wall be safe, but tends to be overly conservative. Further refinement of the model for wood is needed.

scholarly journals Field Study of Hygrothermal Performance of Cross‐Laminated Timber Wall Assemblies with Built‐In Moisture

2021 ◽  
Author(s):  
Victoria Ruth McClung
Keyword(s):  
North America ◽  
Seismic Performance ◽  
Field Data ◽  
Cross Laminated Timber ◽  
Hygrothermal Simulation ◽  
Potential Market ◽  
Hygrothermal Performance ◽  
Drying Behaviour ◽  
The Given

Cross-laminated timber (CLT) panels have potential market in North America for building mid-rise structures due to their good structural and seismic performance, lightweight, and prefabricated nature. However, to ensure long-term durability, the hygrothermal performance of CLT wall assemblies needs to be evaluated in terms of drying and wetting potential before their widespread adoption in North America. A test wall was constructed with initially wetted CLT panels, and monitored over a year. The drying behaviour of the panels was analysed, and results were compared to hygrothermal simulations. It was found from the field data that no tested wall assemblies in the given climate prevented the panels from drying in enough time to prevent decay initiation. The hygrothermal simulation program is capable of predicting general trends, and can predict if a wall be safe, but tends to be overly conservative. Further refinement of the model for wood is needed.

Sophistry, Security, and Socio-Political Structures in the American Revolution; or, Why Jamaica did not Rebel

1986 ◽  
Vol 29 (2) ◽  
pp. 319-344 ◽  
Author(s):  
T. R. Clayton
Keyword(s):  
North America ◽  
British Empire ◽  
American Revolution ◽  
North American ◽  
Western Hemisphere ◽  
American Colonies ◽  
Constitutional Principle ◽  
Mother Country ◽  
Political Structures

Britain's most important American colonies did not rebel in 1776. Thirteen provinces did declare their independence; but no fewer than nineteen colonies in the western hemisphere remained loyal to the mother country. Massachusetts and Virginia may have led the American revolution, but they had never been the leading colonies of the British empire. From the imperial standpoint, the significance of any of the thirteen provinces which rebelled was pale in comparison with that of Jamaica or Barbados. In the century before 1763 the recalcitrance of these two colonies had been more notorious than that of any mainland province and had actually inspired many of the imperial policies cited as long-term grievances by North American patriots in 1774. Real Whig ideology, which some historians have seen as the key to understanding the American revolution, was equally understood by Caribbean elites who, like the continental, had often proved extremely sensitive on questions of constitutional principle. Attacks of ‘frenzied rhetoric’ broke out in Jamaica in 1766 and Barbados in 1776. But these had nothing whatsoever to do with the Stamp Act or events in North America.

scholarly journals Defining Long-term Outcomes With Living Donor Liver Transplantation in North America

2015 ◽  
Vol 262 (3) ◽  
pp. 465-475 ◽  
Author(s):  
Kim M. Olthoff ◽  
Abigail R. Smith ◽  
Michael Abecassis ◽  
Talia Baker ◽  
Jean C. Emond ◽  
...  
Keyword(s):  
Liver Transplantation ◽  
North America ◽  
Living Donor ◽  
Living Donor Liver Transplantation ◽  
Long Term Outcomes ◽  
Donor Liver ◽  
Donor Liver Transplantation

scholarly journals Climatological and statistical characteristics of the Haines Index for North America

2007 ◽  
Vol 16 (2) ◽  
pp. 139 ◽  
Author(s):  
Julie A. Winkler ◽  
Brian E. Potter ◽  
Dwight F. Wilhelm ◽  
Ryan P. Shadbolt ◽  
Krerk Piromsopa ◽  
...  
Keyword(s):  
North America ◽  
Spatial Variability ◽  
Atmospheric Pressure ◽  
Statistical Characteristics ◽  
Potential Contribution ◽  
Extensive Analysis ◽  
Temperature And Humidity ◽  
Humidity Measurements ◽  
Operational Tool

The Haines Index is an operational tool for evaluating the potential contribution of dry, unstable air to the development of large or erratic plume-dominated wildfires. The index has three variants related to surface elevation, and is calculated from temperature and humidity measurements at atmospheric pressure levels. To effectively use the Haines Index, fire forecasters and managers must be aware of the climatological and statistical characteristics of the index for their location. However, a detailed, long-term, and spatially extensive analysis of the index does not currently exist. To meet this need, a 40-year (1961–2000) climatology of the Haines Index was developed for North America. The climatology is based on gridded (2.5° latitude × 2.5° longitude) temperature and humidity fields from the NCEP/NCAR reanalysis. The climatology illustrates the large spatial variability in the Haines Index both within and between regions using the different index variants. These spatial variations point to the limitations of the index and must be taken into account when using the Haines Index operationally.

The Effects of Long‐Term Land‐Use Change on Soil Properties in Perth, Ontario Canada

2016 ◽  
Author(s):  
Trina Stephens
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
North America ◽  
Land Use Change ◽  
Soil Properties ◽  
Carbon Storage ◽  
Organic Matter Content ◽  
Matter Content ◽  
Topographic Gradients

Land‐use change can have a major impact on soil properties, leading to long‐term changes in soilnutrient cycling rates and carbon storage. While a substantial amount of research has been conducted onland‐use change in tropical regions, empirical evidence of long‐term conversion of forested land toagricultural land in North America is lacking. Pervasive deforestation for the sake of agriculturethroughout much of North America is likely to have modified soil properties, with implications for theglobal climate. Here, we examined the response of physical, chemical and biological soil properties toconversion of forest to agricultural land (100 years ago) on Roebuck Farm near Perth, Ontario, Canada.Soil samples were collected at three sites from under forest and agricultural vegetative cover on bothhigh‐ and low‐lying topographic positions (12 locations in total; soil profile sampled to a depth of 40cm).Our results revealed that bulk density, pH, and nitrate concentrations were all higher in soils collectedfrom cultivate sites. In contrast, samples from forested sites exhibited greater water‐holding capacity,porosity, organic matter content, ammonia concentrations and cation exchange capacity. Many of these characteristics are linked to greater organic matter abundance and diversity in soils under forestvegetation as compared with agricultural soils. Microbial activity and Q10 values were also higher in theforest soils. While soil properties in the forest were fairly similar across topographic gradients, low‐lyingpositions under agricultural regions had higher bulk density and organic matter content than upslopepositions, suggesting significant movement of material along topographic gradients. Differences in soilproperties are attributed largely to increased compaction and loss of organic matter inputs in theagricultural system. Our results suggest that the conversion of forested land cover to agriculture landcover reduces soil quality and carbon storage, alters long‐term site productivity, and contributes toincreased atmospheric carbon dioxide concentrations.

scholarly journals Changing forest water yields in response to climate warming: results from long‐term experimental watershed sites across North America

2014 ◽  
Vol 20 (10) ◽  
pp. 3191-3208 ◽  
Author(s):  
Irena F. Creed ◽  
Adam T. Spargo ◽  
Julia A. Jones ◽  
Jim M. Buttle ◽  
Mary B. Adams ◽  
...  
Keyword(s):  
North America ◽  
Climate Warming

scholarly journals A survey of short-term and long-term stability of tube parameters in a mammography unit

2014 ◽  
Vol 29 (4) ◽  
pp. 321-325
Author(s):  
Jovica Praskalo ◽  
Jasna Davidovic ◽  
Biljana Kocic ◽  
Monika Zivkovic ◽  
Svetlana Pejovic
Keyword(s):  
Screening Program ◽  
Short Term ◽  
X Ray ◽  
Term Stability ◽  
Long Term Stability ◽  
Mammography Screening Program ◽  
The Republic ◽  
Set Up ◽  
The Given

In order to set up a successful mammography screening program in the Republic of Srpska, a Siemens Mammomat 1000 X-ray machine was selected for analysis as the said mammography system is widely used in clinical practice. The variations in tube parameters (specific air kerma, high-voltage accuracy and reproducibility, linearity between exposure and dose exposure time) were monitored over a five-year period, from 2008 to 2012. In addition, due to observed daily fluctuations for chosen parameters, a series of measurements were performed three times a day within a single-month period (mainly October 2012). The goal of such an experimental set up is to assess short-term and long-term stability of tube parameters in the given mammography unit and to make a comparison between them. The present paper shows how an early detection of significant parameter fluctuations can help eliminate irregularities and optimize the performance of mammography systems.

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