scholarly journals A Nondestructive Indirect Approach to Long-Term Wood Moisture Monitoring Based on Electrical Methods

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2373 ◽  
Author(s):  
Slávik ◽  
Čekon ◽  
Štefaňák
Keyword(s):  
Building Structures ◽  
Electric Resistance ◽  
Digital Signals ◽  
Wood Moisture ◽  
Moisture Contents ◽  
Spruce Wood ◽  
Moisture Protection ◽  
Electrical Methods ◽  
Rc Circuit

Wood has a long tradition of use as a building material due its properties and availability. However, it is very sensitive to moisture. Wood components of building structures basically require a certain level of moisture protection, and thus moisture monitoring to ensure the serviceability of such components during their whole lifespan while integrated within buildings is relevant to this area. The aim of this study is to investigate two moisture monitoring techniques promoting moisture safety in wood-based buildings (i.e., new structures, as well as renovated and protected buildings). The study is focused on the comparison of two electrical methods that can be employed for the nondestructive moisture monitoring of wood components integrated in the structures of buildings. The main principle of the two presented methods of the moisture measurement by electric resistance is based on a simple resistor–capacitor (RC) circuit system improved with ICM7555 chip and integrator circuit using TLC71 amplifier. The RC-circuit is easier to implement thanks to the digital signals of the used chip, whilst the newly presented integration method allows faster measurement at lower moisture contents. A comparative experimental campaign utilizing spruce wood samples is conducted in this relation. Based on the results obtained, both methods can be successfully applied to wood components in buildings for moisture contents above 8%.

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.

scholarly journals Most Frequent Problems of Building Structures of Urban Apartment Buildings from 2nd Half of 19th Century and the Start of 20th Century

Buildings ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 27
Author(s):  
Klara Kroftova
Keyword(s):  
20Th Century ◽  
19Th Century ◽  
Residential Building ◽  
Structural Safety ◽  
Horizontal Load ◽  
Building Structures ◽  
Speed Up ◽  
The 19Th Century ◽  
Basic Prerequisite

An urban residential building from the second half of the 19th century and the start of the 20th century, the so-called tenement house, is a significant representative of the architecture of the developing urban fabric in Central Europe. The vertical and horizontal load-bearing structures of these houses currently tend to show characteristic, repeated defects and failures. Their knowledge may, in many cases, facilitate and speed up the design of the historic building’s restoration without compromising its heritage value in this process. The article presents the summary of the most frequently occurring defects and failures of these buildings. The summary, however, is not an absolute one, and, in the case of major damage to the building, it still applies that, first of all, a detailed analysis of the causes and consequences of defects and failures must be made as a basic prerequisite for the reliability and long-term durability of the building’s restoration and rehabilitation. An integral part of the rehabilitation of buildings must be the elimination of the causes of the appearance of their failures and remediation of all defects impairing their structural safety, health safety and energy efficiency.

Foot-mounted Pedestrian Navigation based on Particle Filter with an Adaptive Weight Updating Strategy

2014 ◽  
Vol 68 (1) ◽  
pp. 23-38 ◽  
Author(s):  
Yang Gu ◽  
Qian Song ◽  
Yanghuan Li ◽  
Ming Ma
Keyword(s):  
Particle Filter ◽  
A Priori ◽  
Close Relation ◽  
Building Structures ◽  
New Approach ◽  
Pedestrian Navigation ◽  
Regular Structures ◽  
Time Varying Parameter ◽  
Adaptive Weight

The algorithm flow of an inertial-based Pedestrian Navigation System (PNS) can be divided into a trajectory-generation stage and trajectory-calibration stage. The Zero-velocity UPdaTe (ZUPT)-aided Extended Kalman Filter (EKF) algorithm is commonly used to resolve the trajectory of a walking person, but it still suffers from long-term drift. Many methods have been developed to suppress these drifts and thus to calibrate the trajectory generated by the previous stage. However, these methods have certain requirements, such as explicit map information or frequent location revisits, which are hard to satisfy in such situations as Search and Rescue (SAR) operations. A new approach is proposed in this paper that requires no explicit presupposition. This approach is based on a particle filter framework, with the weight of particles being adaptively adjusted according to the a priori knowledge of building structures and human behaviours. The distribution of particle weights is designed with awareness of the regular structures of buildings. The time-varying parameter of the distribution is acquired from a Hidden Markov Model (HMM) based on the foregoing odometry, which has a close relation with human behaviour. HMM is trained offline based on samples acquired in advance. Many real-world experiments under various scenarios were performed, and the results indicate good accuracy and robustness of the proposed approach.

scholarly journals Long-Term Deformation Monitoring of Metro-Tunnel Airshaft Excavation during Construction Stage

2012 ◽  
Vol 8 (10) ◽  
pp. 972893 ◽  
Author(s):  
L. Ran ◽  
T. H. Yi ◽  
X. W. Ye ◽  
X. B. Dong
Keyword(s):  
Deformation Monitoring ◽  
Geological Condition ◽  
Building Structures ◽  
Construction Site ◽  
Construction Stage ◽  
Transit System ◽  
Depth Direction ◽  
Metro Tunnel ◽  
Metro Systems

The project of Hangzhou Metro Line 1 is the first metro line of the urban rapid rail transit system in Hangzhou, China, which is one of the largest municipal projects of Hangzhou and is being constructed commencing from March 28, 2007 and expected to be completed by October 1, 2012. This metro line has a total length of 48 km and 34 stations, connecting Hangzhou downtown with the suburban area of the city. Owing to the complex geological condition, harsh construction situation, and immature computational methodology, construction of metro systems is often subjected to considerable sources of uncertainties. To ensure the safety of the adjacent building structures, it is a vital necessity to monitor deep excavations of metro tunnels at their in-construction stage. This paper introduces the instrumentation system for settlement monitoring of a metro-tunnel airshaft of the project of Hangzhou Metro Line 1 during the construction of deep excavation. The long-term settlement data monitored by the measurement markers installed at the surface ground and in the depth direction of the airshaft excavation construction site are analyzed and presented in detail. The obtained results indicate that the settlements at the instrumented locations of the construction site during different construction steps vary steadily in an allowable variation range.

INTERNAL WATER RELATIONS OF YELLOW BIRCH AT CHALK RIVER

1959 ◽  
Vol 37 (5) ◽  
pp. 789-799 ◽  
Author(s):  
D. A. Fraser ◽  
H. T. Dirks
Keyword(s):  
Moisture Content ◽  
Water Relations ◽  
Field Capacity ◽  
Yellow Birch ◽  
Mature Trees ◽  
Wood Moisture ◽  
Moisture Contents ◽  
Internal Water ◽  
Birch Trees ◽  
Wilting Point

Wood moisture was measured in the butt of healthy and decadent yellow birch trees growing on various sites in the summers of 1950 and 1952. The moisture content decreased from almost 100% in May to about 60% in late June when the leaves were fully unfolded. Wood moisture was usually 5 to 15% higher in the butt of decadent trees than in healthy trees during the 2 years of investigations. It was higher in the trunk of trees on a dry site during a wet summer and on a wet site during a somewhat dry summer.Relative turgidity in leaves was measured in mature trees as well as in leaves of seedlings growing on soils with varied moisture contents. Relative turgidity was usually less during the day. During periods of drought it decreased even during the night. Exceptions observed may have been caused by leaf absorption of dew. In young birch seedlings relative turgidity values varied between 65 and 50% in soils ranging from 100 to 70% of field capacity. As the soil wilting point was approached, relative turgidity of leaves decreased to about 35%.

scholarly journals Analyzing Near-Surface Regions of Hydrophobic and Long-Term Weathered Natural Stones at Microscopic Scale

Heritage ◽  
2020 ◽  
Vol 3 (2) ◽  
pp. 457-473
Author(s):  
Franziska Braun ◽  
Jeanette Orlowsky ◽  
Stefan Brüggerhoff
Keyword(s):  
Structural Changes ◽  
Color Difference ◽  
Outdoor Exposure ◽  
Material Surface ◽  
Building Structures ◽  
Near Surface ◽  
Visual Appearance ◽  
Microscopic Scale ◽  
Surface Damages

The visual appearance of building structures is an important attribute which reflects the character and identity of a region. Due to the influence of weathering, the surfaces of building stones alter, leading to aesthetic changes of the material surface such as discoloration or darkening. In this study, near-surface regions of weathered Baumberger (BST), Schleeriether (SST), and Obernkirchener Sandstones (OKS) have been analyzed at the microscopic scale in order to investigate the intensity and the extent of visual as well as structural changes and how both can be affected due to the presence of surface treatments with hydrophobing agents. It could be detected that aesthetic changes appeared already after 2 years of outdoor exposure, with the slightest variations on BST surfaces, followed by SST and OKS. The use of hydrophobing agents leads to a reduction in surface darkening in the short term. After long-term weathering, no significant changes are visible, as similar values in total color difference (ΔE*) were measured. Biogenic growth and the formation of black weathering crusts are the main reasons for color alterations in the case of the examined stones. The surface damages occur especially on calcareous (BST) followed by clayey (SST) and quartzitic (OKS) stone surfaces.

Basic Study on Creep Properties of Eucalyptus Wood

2014 ◽  
Vol 911 ◽  
pp. 232-237
Author(s):  
Yuan Rong Ma ◽  
Xian Jun Li ◽  
Biao Deng ◽  
Ying She Luo
Keyword(s):  
Model Parameters ◽  
Short Term ◽  
Basic Study ◽  
Burger Model ◽  
Creep Properties ◽  
Eucalyptus Plantation ◽  
Moisture Contents ◽  
Creep Curves ◽  
Term Creep

The study tested the short-term bending creep curves of Eucalyptus Plantation Wood under different loads, moisture contents and temperatures, analyzed the influence of load, moisture content and temperature on creep of Eucalyptus. Guided by the rheological theory, the study adopted the Burger rheological model to do the curve fitting and solved the model parameters. A defect found from Burger model in simulating long-term creep properties of wood was preliminary discussed and remedied. The equivalence of creep test and relaxation one was discussed.

The long-term monitoring of civil engineering and building structures—developments in techniques for monitoring corrosion in reinforced and post-tensioned concrete

1998 ◽  
Vol 212 (3) ◽  
pp. 175-188 ◽  
Author(s):  
G P Hammersley ◽  
M J Dill
Keyword(s):  
Civil Engineering ◽  
Warning System ◽  
In Situ Monitoring ◽  
Building Structures ◽  
Actual Performance ◽  
Structural Problems ◽  
Long Term Monitoring ◽  
Term Monitoring ◽  
Post Tensioned

An important step in the progress towards smart structures is the development of reliable systems for the long-term monitoring of performance. Data obtained from monitoring can provide an early warning system to maximize the safe use of structures, contribute towards planned maintenance by giving advanced notice of durability or structural problems and provide information on actual performance, which can be fed back into the design process. This paper sets out to describe some developments in permanent in situ monitoring systems which have achieved practical use on civil engineering and building structures constructed from concrete, concentrating on the key area of corrosion of reinforced and post-tensioned concrete. The techniques are illustrated with case histories.

scholarly journals Temperature Requirements for the Storage and Germination of Delphinium × cultorum Seed

HortScience ◽  
1992 ◽  
Vol 27 (9) ◽  
pp. 989-992 ◽  
Author(s):  
William J. Carpenter ◽  
Joseph F. Boucher
Keyword(s):  
Seed Germination ◽  
Seed Storage ◽  
Moisture Contents ◽  
Long Term Storage ◽  
Subzero Temperatures ◽  
Temperature Requirements ◽  
Cultivar Responses ◽  
Term Storage ◽  
Storage Temperatures

Delphinium seed germination was about equal in light or darkness. Seed total germination percentages were highest and about equal at constant 15 or 20C and alternating (12 h) 10/20C, 15/25C, or 20/30C. The most rapid and uniform germination generally occurred at constant 20C. Storing seeds dry at 2C for 3 weeks before germination reduced the days to 50% of final germination (T50) and between 10% and 90% germination (T90 - T10) but did not increase total germination. The seeds had only limited desiccation tolerance, with `Magic Fountains Lavender' having declining germination percentages at moisture contents below 7.0% and `Magic Fountains Lilac' below 6.7%. Seeds tolerated storage at low, nonfreezing or subzero temperatures, but cultivar responses differed. `Magic Fountains Lavendar' had progressively lower germination percentages as storage temperatures declined from 5 to –20C, while `Magic Fountains Lilac' germination increased. The relative humidity (RH) and temperature that delphinium seed received during long-term storage influenced germination. Germination after seed storage at 5C was higher, earlier, and more uniform than after 15 or 25C storage. The highest total germination percentages occurred following seed storage at 5C and 30% to 50% RH, the shortest T50 from 35% to 55% RH, and shortest spans (T90 - T10) from 25% to 50% RH.

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