Comparison between Predicted and Measured Moisture Content and Climate in 12 Monitored Timber Structures in Switzerland

Wood is a hygroscopic material that primarily adapts its moisture content to the surrounding relative humidity. The climate in a structure or building depends on the building type and the region the structure is located in. In this study, the effect of region on the moisture content of wood was investigated. Measurements taken in 12 ventilated timber structures were compared to the theoretical equilibrium moisture content calculated from the relative humidity and temperature in 107 meteorological stations across Switzerland. The monitored load-bearing elements were made of softwood and protected from the direct impact of weather. The climatic conditions around the Alps, a mountain range that runs from France to Austria and crosses Switzerland, can be divided into the following three different regions: (1) south of the Alps, where the climate is affected mainly by the Mediterranean sea; (2) north of the Alps, where the climate is affected by the Atlantic Ocean; and (3) the inner Alps, where the climate is considered to be relatively dry. The climatic conditions of the three separate regions were reflected in the measurements made in the monitored timber structures. Differences between the regions were quantified. The moisture content and relative humidity, similarly to temperature, depended on altitude (above sea level).

Analysis of a Topsoil Moisture Regime Through an Effective Precipitation Index for the Locality of Nitra, Slovakia

The aim of this work was to analyze and statistically confirm the relationship between the computed daily values of the Effective Precipitation Index (EP365) and the measured moisture content of the topsoil of a research site near Nitra, Slovakia. The statistical analysis (coefficients of determination) confirmed the strong correlation. Subsequently each day’s mean of EP365 (MEP) was used to quantify the long-term deficit or surplus of the soil water supply in the individual years. The daily values of the EP365 index provide a more detailed view of the development of the topsoil’s moisture regime. According to the deviation of EP (DEP) from the 14-year MEP, the most extreme dry periods prevailed during the years 2015, 2017 and 2018. Therefore, the 2012–2018period was evaluated as dry, and the topsoil moisture regime described through the MEP index was compared with the course of the MEP index from the normal (slightly humid) period of the years 2005 – 2011.

Improving the accuracy of wood moisture content estimation in four European softwoods from Spain

Aim of study: To obtain improved models to predict, with an error of less than ± 2.0%, the gravimetric moisture content in four different softwoods commonly present in the Spanish and European markets, based on electrical resistance measurements. This improved moisture content estimation is useful not only for assessing the quality of wood products, especially in the case of laminated products, during the transformation and delivery process, but also for accurately monitoring the evolution of moisture in wood present in bridges and buildings, which is of great importance for its maintenance and service life improvement.Area of study: The study was carried out on samples of Scots, laricio, radiata and maritime pines of Spanish provenances.Material and methods: On 50x50x20 mm3 solid wood samples (36 per species, 9 per condition), conditioned at 20ºC (±05ºC) and 40±5%, 65±5%, 80±5% or 90±5% Relative Humidity (RH), electrical resistance and oven-dry moisture content was measured. The Samuelsson's model was fitted to data to explain the relationship between the two variables. The accuracy of the model was evaluated by the use of an external sample.Main results: With the proposed mathematical functions the wood moisture content can be estimated with an error of ±0.9% in the four species, confirming the effectiveness of this nondestructive methodology for accurate estimation and monitoring of moisture content.Research highlights: our results allow the improvement of the moisture content estimation technique by resistance-type methodologies.Keywords: Resistance-type moisture meter; species correction.Abbreviations used: MC: Moisture content; RH: relative Humidity; R: electrical resistance; RP: wood electrical resistance measured parallel to the grain; RT: electrical resistance measured perpendicular (transversally) to the grain; GM-MC: gravimetrically measured moisture content.

Improving the accuracy of wood moisture content estimation in four European softwoods from Spain

Aim of study: To obtain improved models to predict, with an error of less than ± 2.0%, the gravimetric moisture content in four different softwoods commonly present in the Spanish and European markets, based on electrical resistance measurements. This improved moisture content estimation is useful not only for assessing the quality of wood products, especially in the case of laminated products, during the transformation and delivery process, but also for accurately monitoring the evolution of moisture in wood present in bridges and buildings, which is of great importance for its maintenance and service life improvement.Area of study: The study was carried out on samples of Scots, laricio, radiata and maritime pines of Spanish provenances.Material and methods: On 50x50x20 mm3 solid wood samples (36 per species, 9 per condition), conditioned at 20ºC (±05ºC) and 40±5%, 65±5%, 80±5% or 90±5% Relative Humidity (RH), electrical resistance and oven-dry moisture content was measured. The Samuelsson's model was fitted to data to explain the relationship between the two variables. The accuracy of the model was evaluated by the use of an external sample.Main results: With the proposed mathematical functions the wood moisture content can be estimated with an error of ±0.9% in the four species, confirming the effectiveness of this nondestructive methodology for accurate estimation and monitoring of moisture content.Research highlights: our results allow the improvement of the moisture content estimation technique by resistance-type methodologies.Keywords: Resistance-type moisture meter; species correction.Abbreviations used: MC: Moisture content; RH: relative Humidity; R: electrical resistance; RP: wood electrical resistance measured parallel to the grain; RT: electrical resistance measured perpendicular (transversally) to the grain; GM-MC: gravimetrically measured moisture content.

Drying Tectona grandis boards using the simulating solar kiln conditions technique

Timber cracking, drying stress residuals, and the change of moisture content profile were investigated during the drying of Tectona grandis boards in a conventional laboratory kiln. The study applied a technique that simulated solar kiln conditions using a conventional laboratory kiln to dry timber, based on Vientiane’s climatic conditions (Laos). The theoretical recharge and discharge model was used to generate the potential drying schedule for the Vientiane area; then the drying schedule was mimicked in a conventional laboratory kiln. Timber cracking and drying stress residual were monitored and measured using Image J software, and the change of moisture content profile was determined, based on the oven dry method. Measured moisture content data were compared with the theoretical drying model. The results showed that teak boards, of 25 mm thick, had no cracking. The drying stress residual was 0.8 ± 0.3 mm with the maximum of 1.53 mm. The initial average moisture content of 62% decreased to 12% within 16 d, while the case and core moisture contents reached 12% and 14%, respectively. The drying model described the changes of moisture content profile during drying, with a maximal error of 5%.

Características físico-químicas y microbiológicas del compostaje de bagazo de agave tequilero a escala industrial

The aim of the present study was to evaluate some physicochemical characteristics of large scale composting process of tequila agave bagasse, and also quantify the population dynamic of bacteria, fungi and actinomycetes througout 300 days. A large windrow of agave bagasse of approximately 195 m (~331 t) was set and regularly monitored. Thereafter a pile section was reubicated to continue the evaluation. The windrow was sampled every 15 days and the following parameters were measured: moisture content, temperature, pH, electric conductivity (EC), the organic matter (OM), C/N ratio and the population dynamic of bacteria, fungi and actynomicetes in colony forming units. From the very beginning of composting the temperature of the windrow reached the thermophylic phase (>45 °C) and continued up to 270 days. However, at the end of the study the temperature felt down till 42 °C due to the reduction on moisture content (<30%). The highest EC registered was 1.5 dS/m; the OM remained between 70-35% and the C/N ratio varied between 96.9 initial and 29.6 final. Actinomycetes were the most dominant group especially in the last weeks of composting, which infers the possibility of using this type of compost in soil bioremediation.

MAKING NATA DE CASSAVA FROM RENGGINANG LIQUID WASTE USING ACETOBACTER XYLIUM

Processed cassava liquid waste in Nyamok Village causes a decrease in water quality with amarked unpleasant odor. The liquid waste comes from the washing process of raw materials andstarch deposited water containing starch. Glucose in cassava liquid waste can be a source of energyfor Acetobacter Xylinum to form cellulose called nata de cassava. This study examines the potential ofRengginang UKM liquid waste as a substrate / raw material for making nata de cassava as a newmaterial.Based on previous research, it was obtained optimization of various percentages of sugar(carbon source) and urea (nitrogen source). Therefore, this study aims to determine the optimizationof the percentage of sugar and urea given in fermentation by evaluating, among others, the test watercontent (moisture content), tensile strength test and elongation. The study was conducted with wastepreparation and processed into nata de cassava with variations of sugar and urea for 8 days offermentation. Wet nata de cassava thickness is measured to determine the optimal recipe. Thefermentation optimization results measured moisture content, dried and tested the tensile strength andelongation. The data obtained were tested statistically with two-way ANOVA. The results showed thatsugar and urea are very influential in the process of bacterial cellulose formation based on anova test,namely F> Fc (11.8> 2.9). The optimum conditions obtained are the addition of sugar 15 grams / Land urea 2 grams / L, with a thickness of 12.1 mm. Moisture content value of 97.97%, tensile strengthof 14.31 N/mm2 and elongation at 3.83%.Keyword: Nata de cassava, Urea,Sugar,Moisture content, Mensile strengt

Thermal Remote Sensing For Moisture Content Monitoring of Mine Tailings: Laboratory Study

Mining produces massive volumes of mine tailings that are deposited into large-scale mine tailings impoundments. A key environmental objective of managing these large impoundments is mitigating fugitive dust emissions by monitoring and controlling moisture, because moisture directly affects the tailings’ strength and the ability to apply dust control measures using motorized equipment. Therefore, understanding the spatial and temporal variations in moisture content for surface tailings is critical for characterizing dust susceptibility and trafficability. Remote sensing has been proven to be a useful tool for similar applications. This study utilized laboratory testing conducted on iron mine tailings to verify that: (1) a relationship exists between moisture content and strength for the surface of mine tailings, and (2) thermal remote sensing can be used to infer spatial variations in moisture content for surface tailings. Multivariate regressions were developed to identify the critical remote sensing and climatic variables and evaluate their influence in remotely measured moisture content. For tailings samples collected from two different North American iron mines, regressions using sample temperature and ambient humidity were able to predict surface moisture content (R2> 0.9).

The Influence of Specimen Size and Distance to a Surface on Resistive Moisture Content Measurements in Wood

The moisture content of wood is commonly determined by measuring the electrical resistance between two electrodes inserted in the wood. However, problems using this method close to wood surfaces were reported in a previous study. In the present study, the effect of the distance to a surface and the specimen size on the measured electrical resistance was studied analytically as follows. The two electrodes create an electrical potential in the wood specimen. The boundary condition for the electrical potential is that the electrical current across all specimen surfaces is zero, which is achieved by using a suitable array of mirror sources. The analytical solution for the electrical potential was used to analyse the influence of the distance from the electrodes to the specimen surface as well as the size of the specimen. In addition, the error in moisture content was evaluated. The effect of the distance to a surface and the specimen size depended on the equivalent radius of the electrodes; if large electrodes are used in small specimens or close to surfaces, there is a risk that a higher resistance is measured which results in slightly lower measured moisture content than the actual moisture content of the specimen.

Application of TDR Method for Moisture Profiles Measurement in Cellular Concrete

Possible applicability of TDR method for continuous monitoring of moisture content in porous building materials is studied in the paper. TDR method, originally proposed for application in soil science, represents prospective tool for long time monitoring of moisture content in laboratory as well as in-situ conditions neglecting the effect of salts presence in researched material on accuracy of measured moisture content. The basic experimental setup of the TDR method is adjusted to the measurement of water content in building materials. The practical application of the method is presented on the measurement of moisture profiles in rod-shaped sample of cellular concrete.