Moisture content and material density affects severity of frost damage in earthen heritage

2022 ◽  
pp. 153047
Author(s):  
Jenny Richards ◽  
Qinglin Guo ◽  
Heather Viles ◽  
Yanwu Wang ◽  
Bo Zhang ◽  
...  
Keyword(s):  
Moisture Content ◽  
Frost Damage ◽  
Material Density

scholarly journals Impact of frost temperature and moisture content on frost damage to ceramic bricks

2019 ◽  
Vol 282 ◽  
pp. 02013
Author(s):  
Hans Janssen ◽  
Chi Feng ◽  
Staf Roels
Keyword(s):  
Moisture Content ◽  
Building Materials ◽  
Ultrasonic Method ◽  
Frost Damage ◽  
Testing Methods ◽  
High Moisture ◽  
Building Facades ◽  
Reliable Knowledge ◽  
Modulus Reduction ◽  
Very High

Reliable knowledge on how frost deteriorates building materials is necessary when assessing the hygrothermal performances of building facades. Unfortunately, the current frost-thaw testing methods do not offer dependable knowledge, as they only test at very low temperatures and very high moisture contents, contrary to the spectrum of milder conditions usually met in reality. This paper therefore studies frost damage to four ceramic bricks, with accele-rated frost-thaw tests at frost temperatures from -2 °C to -20 °C and moisture saturation degrees from 0.1 to 1.0. The ultrasonic method is used to quantify the resulting frost damage, with the Young’s modulus reduction as index. The actual frost temperature and moisture content affect the level of frost damage, an effect which is not recognised however in current frost-thaw test protocols.

scholarly journals Hygrothermal simulation assessment of internal insulation systems for retrofitting a historic Danish building

2019 ◽  
Vol 282 ◽  
pp. 02049
Author(s):  
Vasilis Soulios ◽  
Ernst Jan de Place Hansen ◽  
Ruut Peuhkuri
Keyword(s):  
Moisture Content ◽  
Frost Damage ◽  
Energy Performance ◽  
Hygrothermal Simulation ◽  
Moisture Content Level ◽  
Increased Risk ◽  
Hygrothermal Performance ◽  
Key Factor ◽  
Insulation Systems ◽  
The One

The built environment is accountable for 1/3 of the European energy consumption. Thermal insulation is a key factor affecting the energy performance of buildings. Historic buildings typically were made with solid external walls of brick masonry or natural stone, rarely insulated afterwards. Often the buildings have worth-preserving façades making internal insulation the only feasible technique, however significantly modifying the hygrothermal performance of the façade. The research objective of this paper is to simulate the hygrothermal performance of solid masonry walls in an old Danish hospital that will be internally insulated following the Danish requirement (U-value) for external walls (change of use of buildings) and transformed into dwellings, involving different insulation systems. Heat loss and masonry moisture content level after adding internal insulation and the possible effects of hydrophobization on the moisture content is simulated. Simulations show an increased moisture content in the original wall when adding internal insulation implying an increased risk for moisture-related damage (mould growth, frost damage and interstitial condensation). The results also show that hydrophobic impregnation of the internally insulated facades may be vital in avoiding moisture problems and securing a moisture-safe energy renovation of buildings like the one studied.

Specimen Collection Effect in Scanning Electron Microscopy Images

1972 ◽  
Vol 30 ◽  
pp. 448-449
Author(s):  
J. Temple Black ◽  
Jose Guerrero
Keyword(s):  
Surface Morphology ◽  
Secondary Electron Emission ◽  
Secondary Electrons ◽  
Charge Effects ◽  
Material Density ◽  
Specimen Collection ◽  
The Subject ◽  
Curved Paths ◽  
Subject Material ◽  
Microscopy Images

In the SEM, contrast in the image is the result of variations in the volume secondary electron emission and backscatter emission which reaches the detector and serves to intensity modulate the signal for the CRT's. This emission is a function of the accelerating potential, material density, chemistry, crystallography, local charge effects, surface morphology and especially the angle of the incident electron beam with the particular surface site. Aside from the influence of object inclination, the surface morphology is the most important feature In producing contrast. “Specimen collection“ is the name given the shielding of the collector by adjacent parts of the specimen, producing much image contrast. This type of contrast can occur for both secondary and backscatter electrons even though the secondary electrons take curved paths to the detector-collector.Figure 1 demonstrates, in a unique and striking fashion, the specimen collection effect. The subject material here is Armco Iron, 99.85% purity, which was spark machined.

Preparation and Standardization of a Stable AHF Plasma

1968 ◽  
Vol 19 (03/04) ◽  
pp. 423-429 ◽  
Author(s):  
G. M Thelin ◽  
Keyword(s):  
Moisture Content ◽  
Primary Standard ◽  
Healthy Male ◽  
Healthy Donors ◽  
Fresh Plasma

SummaryA stable, lyophilized AHF reference plasma has been prepared from pooled plasma from at least 50 normal healthy donors and standardized against a primary standard of fresh plasma from 20 healthy male donors aged 20 to 40. Average AHF potency of a typical lot is 98.8%, and moisture content is less than 0.5%. Under storage at -25° C, this AHF reference plasma is stable for at least 18 months. It has been used in several major coagulation laboratories, and has given consistently satisfactory and reproducible results in AHF assays.

Improvement in the Fock test for determining the reactivity of dissolving pulp

TAPPI Journal ◽  
2013 ◽  
Vol 12 (11) ◽  
pp. 21-26 ◽  
Author(s):  
CHAO TIAN ◽  
LINQIANG ZHENG ◽  
QINGXIAN MIAO ◽  
CHRIS NASH ◽  
CHUNYU CAO ◽  
...  
Keyword(s):  
Moisture Content ◽  
Sodium Hydroxide ◽  
Constant Temperature ◽  
Carbon Disulfide ◽  
Testing Procedure ◽  
Dissolving Pulp ◽  
Water Bath ◽  
Testing Conditions ◽  
Pulp Sample ◽  
Fock Reactivity

The Fock test is widely used for assessing the reactivity of dissolving pulp. The objective of this study was to modify the method to improve the repeatability of the test. Various parameters that affect the repeatability of the Fock test were investigated. The results showed that Fock reactivity is dependent on testing conditions affecting the xanthation between cellulose and carbon disulfide, such as the moisture content of the pulp sample, sodium hydroxide (NaOH) concentration, xanthation temperature, carbon disulfide dosage, and xanthation time. The repeatability of the test was significantly improved using the following modified testing procedure: air dried sample in the constant temperature/humidity room, xanthation temperature of 66°F (19°C) in a water bath, xanthation time of 3 h, NaOH concentration of 9% (w/w), and 1.3 mL carbon disulfide.

Examination of moisture content variation within an operational wet deck

TAPPI Journal ◽  
2013 ◽  
Vol 12 (1) ◽  
pp. 45-50 ◽  
Author(s):  
LAURENCE SCHIMLECK ◽  
KIM LOVE-MYERS ◽  
JOE SANDERS ◽  
HEATH RAYBON ◽  
RICHARD DANIELS ◽  
...  
Keyword(s):  
Moisture Content ◽  
Southeastern United States ◽  
Forest Products ◽  
Time Domain Reflectometry ◽  
Water Application ◽  
Wood Moisture ◽  
International Paper ◽  
Content Variation ◽  
Moisture Variation

Many forest products companies in the southeastern United States store large volumes of roundwood under wet storage. Log quality depends on maintaining a high and constant wood moisture content; however, limited knowledge exists regarding moisture variation within individual logs, and within wet decks as a whole, making it impossible to recommend appropriate water application strategies. To better understand moisture variation within a wet deck, time domain reflectometry (TDR) was used to monitor the moisture variation of 30 southern pine logs over an 11-week period for a wet deck at the International Paper McBean woodyard. Three 125 mm long TDR probes were inserted into each log (before the deck was built) at 3, 4.5, and 7.5 m from the butt. The position of each log within the stack was also recorded. Mixed-effects analysis of variance (ANOVA) was used to examine moisture variation over the study period. Moisture content varied within the log, while position within the stack was generally not significant. The performance of the TDR probes was consistent throughout the study, indicating that they would be suitable for long term (e.g., 12 months) monitoring.

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