Estudio de la variación del contenido de humedad en el Pinus pinaster Ait. por medio de la técnica no destructiva del georradar / Assessment of the variation of the moisture content in the Pinus pinaster Ait using the non destructive gpr technique

La variación en el contenido de humedad (CH) tiene una influencia significativa tanto en las propiedades físico- químicas de la madera, como en sus propiedades electromagnéticas y por tanto afecta a las características de la propagación de las ondas. En concreto, en este trabajo se estudia la capacidad del georradar (GR) empleando una antena de 1.6GHz de frecuencia central para registrar las variaciones que se producen en la velocidad y en la amplitud de las ondas electromagnéticas cuando se propagan en unas viguetas de madera de Pinus pinaster Ait de uso estructural cuyo CH va disminuyendo. Se ha comprobado como cuando el CH descendía la velocidad de propagación y las amplitudes, tanto de la onda directa como de la reflejada aumentaba. Los altos factores de correlación encontrados demuestran que el GR es una técnica capaz de evaluar, de forma no destructiva, el CH de la madera de uso estructural. The moisture content variations in wood have a significant influence in wood?s physicochemical properties, as well as in its electromagnetic properties and to specific effects upon waves? characteristics. In particular, this paper focuses on the analysis of the Ground-penetrating Radar?s (GPR) using an antenna of 1.6 GHz central frequency capacity to register the velocity and the amplitude of the electromagnetic waves? variation during the drying process of Pinus pinaster Ait timber joists. The results showed that when timber MC descended, the propagation velocity and amplitude of both the direct and the reflected wave increased. The high correlation found between the variables studied demonstrates GPR efficiency and the innovative application of this technique as a non-destructive evaluation tool for timber structures, particularly when studying its moisture content.

Influence of temperature and moisture content in Non-destructive values of Scots pine (Pinus sylvestris L.)

Good results evaluating material properties using non-destructive testing (NDT) techniques have been achieved for decades. Several studies to understand the influence of temperature and moisture content on NDT have concluded different effects. In this study, NDT parameters were measured on the principal structural Spanish sawn timber species, Scots pine (Pinus sylvestris L.). NDT were conducted on 216 specimens of nominal dimensions 20 by 20 by 400 mm. Specimens were divided into several groups and studied at six different temperatures and four different moisture contents. Commercial equipment and techniques applied were Sylvatest Duo (ultrasonic wave technique), Steinkamp BPV (ultrasonic wave technique), and Grindo Sonic Mk5 "Industrial" (vibration analysis technique). Differences in NDT values within specimens at different temperatures and moisture contents were obtained. Main results of this study and relationships that describe changes in NDT values by effect of temperature and moisture content are presented.

Soil moisture content determines the effect of the urease inhibitor NBPT on N2O emissions

Among the mitigation strategies to prevent nitrogen (N) losses from ureic fertilizers, urease inhibitors (UIs) have been demonstrated to promote high N use efficiency by reducing ammonia (NH3) volatilization. In the last few years, some field experiments have also shown its effectiveness in reducing nitrous oxide (N2O) losses from fertilized soils under conditions of low soil moisture. An incubation experiment was carried out with the aim of assessing the main biotic mechanisms behind N2O emissions once that the UIs N-(n-butyl) thiophosphoric triamid (NBPT) and phenil phosphorodiamidate (PPDA) were applied with Urea (U) under different soil moisture conditions (40, 60 and 80 % water-filled pore space, WFPS). In the same study we tried to analyze to what extent soil WFPS regulates the effect of these inhibitors on N2O emissions. The use of PPDA in our study allowed us to compare the effect of NBPT with that of another commercially available urease inhibitor, aiming to see if the results were inhibitor-specific or not. Based on the results from this experiment, a WFPS (i.e. 60 %) was chosen for a second study (i.e. mesocosm experiment) aiming to assess the efficiency of the UIs to indirectly affect N2O emissions through influencing the pool of soil mineral N. The N2O emissions at 40 % WFPS were almost negligible, being significantly lower from all fertilized treatments than that produced at 60 and 80 % WFPS. When compared to U alone, NBPT+U reduced the N2O emissions at 60 % WFPS but had no effect at 80 % WFPS. The application of PPDA significantly increased the emissions with respect to U at 80 % WFPS whereas no significant effect was found at 60 %. At 80 % WFPS, denitrification was the main source of N2O emissions for all treatments. In the mesocosm study, the application of NBPT+U was an effective strategy to reduce N2O emissions (75 % reduction compared to U alone), due to a lower soil ammonium (NH4 +) content induced by the inhibitor. These results suggest that adequate management of the UI NBPT could provide, under certain soil conditions, an opportunity for mitigation of N2O emissions from fertilized soils.

Methodology of image analysis for study of the vertisols moisture content

The main problem to study vertical drainage from the moisture distribution, on a vertisol profile, is searching for suitable methods using these procedures. Our aim was to design a digital image processing methodology and its analysis to characterize the moisture content distribution of a vertisol profile. In this research, twelve soil pits were excavated on a ba re Mazic Pellic Vertisols ix of them in May 13/2011 and the rest in May 19 /2011 after a moderate rainfall event. Digital RGB images were taken from each vertisol pit using a Kodak? camera selecting a size of 1600x945 pixels. Each soil image was processed to homogenized brightness and then a spatial filter with several window sizes was applied to select the optimum one. The RGB image obtained were divided in each matrix color selecting the best thresholds for each one, maximum and minimum, to be applied and get a digital binary pattern. This one was analyzed by estimating two fractal scaling exponents box counting dimension D BC) and interface fractal dimension (D) In addition, three pre-fractal scaling coefficients were determinate at maximum resolution: total number of boxes intercepting the foreground pattern (A), fractal lacunarity (?1) and Shannon entropy S1). For all the images processed the spatial filter 9x9 was the optimum based on entropy, cluster and histogram criteria. Thresholds for each color were selected based on bimodal histograms.

The effect of moisture content on nondestructive probing measurements

When assessing existing timber structures it is not possible to obtain density as the ratio mass/volume, so nondestructive probing methods are used to predict density. As in other nondestructive techniques, moisture content influences measurements. The goal of this paper is to study the influence of timber moisture content on two nondestructive probing techniques (penetration resistance and pullout resistance). 25 large cross section specimens of laricio pine from Spain were measured. The moisture content ranged from 65.1% to 8.3%. Penetration depth decreases and screw withdrawal strength increases when moisture content decreases below the fiber saturation point. There are lineal tendencies in both techniques. No moisture content influence was found in measures above fiber saturation point.

Factors controlling the moisture content of cheese curds /

Includes bibliographical references.

Equilibrium moisture contents of fiber flax /

Caption title.

(Table 3) Boron and chlorine in atmospheric moisture and rain water collected on the shore of the Golubaya Bay in 1970

Boron and chlorine were determined in rain water and in atmospheric moisture condensed in a "Saratov" refrigerator. Ocean is the main source of boron on the earth surface. Boron evaporates from the ocean and enriches atmospheric precipitation: B/Cl ratio of ocean water (0.00024) increases by factor of 10-15. Assuming that the average Cl content in global river runoff is 7.8 mg/l and boron content 0.013 mgl, B/Cl ratio in this runoff is 0.0017. The average B/Cl ratio in rain water of the Golubaya (Blue) Bay (Gelendzhik, Black Sea region) is 0.0026 and in condensates of atmospheric moisture during onshore and offshore winds in the same region it averages from 0.0029 to 0.0033. The maximum boron content in the condensates of this region during onshore winds was 0.032 mg/l and the minimum during offshore winds, 0.004 mg/l. /Cl ratio in sea water over the Atlantic Ocean and in the Gelendzhik area of the Black Sea varied within narrow range, mostly from 0.0025 to 0.0035. Similar B/Cl ratio (0.0024) was found for atmospheric precipitation on the slope of the Terskei Ala-Tau near the Issyk-Kul Lake in 1969. Thus, although chemistries of boron and chlorine (in chlorides) are very different, the B/Cl ratio in the atmosphere is fairly constant. This can be taken as a confirmation of an assumption that salt composition of sea water passes into the atmosphere in molecularly dispersed state. Supposing that the ocean-atmosphere system is in equilibrium as regards to the boron budget, it can be assumed that the same amount of boron passes from the ocean into bottom sediments and from lithosphere rocks and soils into the hydrosphere.

Effect of moisture content on the R-70 self-heating rate of Callide coal

Strip samples from the Boundary Hill pit at Callide have been tested in an adiabatic oven to assess the effect of moisture on the R-70 self-heating rate of coal. The two strip samples tested had R-70 self-heating rate values of 10.23 and 8.61 degrees C/h. As the moisture content of the coal was progressively increased, from the dry state of the test, the R-70 value decreased dramatically. At approximately 40-50% of the moisture holding capacity of the coal, the self-heating rate becomes measurable. Above this critical level of moisture content, the heat produced by oxidation is dissipated by moisture evaporation and coal self-heating is significantly delayed. (c) 2005 Elsevier B.V All rights reserved.

Prediction of vapor-moisture equilibriums for a wood-moisture system using a modified UNIQUAC model

A modified UNIQUAC model has been extended to describe and predict the equilibrium relative humidity and moisture content for wood. The method is validated over a range of moisture content from oven-dried state to fiber saturation point, and over a temperature range of 20-70 degrees C. Adjustable parameters and binary interaction parameters of the UNIQUAC model were estimated from experimental data for Caribbean pine and Hoop pine as well as data available in the literature. The two group-interaction parameters for the wood-moisture system were consistent with using function group contributions for H2O, -OH and -CHO. The result reconfirms that the main contributors to water adsorption in cell walls are the hydroxyl groups of the carbohydrates in cellulose and hemicelluloses. This provides some physical insight into the intermolecular force and energy between bound water and the wood material. (c) 2006 Elsevier Ltd. All rights reserved.

Nondestructive measurement of water content and moisture migration of unsaturated red clays in South China

To reveal the moisture migration mechanism of the unsaturated red clays, which are sensitive to water content change and widely distributed in South China, and then rationally use them as a filling material for highway embankments, a method to measure the water content of red clay cylinders using X-ray computed tomography (CT) was proposed and verified. Then, studies on the moisture migrations in the red clays under the rainfall and ground water level were performed at different degrees of compaction. The results show that the relationship between dry density, water content, and CT value determined from X-ray CT tests can be used to nondestructively measure the water content of red clay cylinders at different migration time, which avoids the error reduced by the sample-to-sample variation. The rainfall, ground water level, and degree of compaction are factors that can significantly affect the moisture migration distance and migration rate. Some techniques, such as lowering groundwater table and increasing degree of compaction of the red clays, can be used to prevent or delay the moisture migration in highway embankments filled with red clays.

Microparticle surface layering through dry coating:impact of moisture content and process parameters on the properties of orally disintegrating tablets

OBJECTIVES: The aim of this study was to investigate the influence of process parameters during dry coating on particle and dosage form properties upon varying the surface adsorbed moisture of microcrystalline cellulose (MCC), a model filler/binder for orally disintegrating tablets (ODTs). METHODS: The moisture content of MCC was optimised using the spray water method and analysed using thermogravimetric analysis. Microproperty/macroproperty assessment was investigated using atomic force microscopy, nano-indentation, scanning electron microscopy, tablet hardness and disintegration testing. KEY FINDINGS: The results showed that MCC demonstrated its best flowability at a moisture content of 11.2% w/w when compared to control, comprising of 3.9% w/w moisture. The use of the composite powder coating process (without air) resulted in up to 80% increase in tablet hardness, when compared to the control. The study also demonstrated that surface adsorbed moisture can be displaced upon addition of excipients during dry processing circumventing the need for particle drying before tabletting. CONCLUSIONS: It was concluded that MCC with a moisture content of 11% w/w provides a good balance between powder flowability and favourable ODT characteristics.

A New Method for Estimating the Moisture Content and Flexibility of Polymerised Bentonite Clay Mat

This paper presents a scientific development to address the current absence of a convenient technique to identify the ductile to brittle transition of bentonite clay mats. The instrumented indentation and 3-point bending tests were performed on different liquid polymer hydrated bentonite clay mats at varying moisture content. Properties measured include modified Brinell Hardness Number (BHN) and elastic structural stiffness (EI). The dependence of flexural stiffness on moisture content is demonstrated to conform to a best power function variation. The ductile to brittle transition of clay mat is affected primarily by the change in the moisture content and for the clay mat to remain flexible, critical moisture content of 1.7 times of its plastic limit is required. Results also indicate that a strong correlation between indentation hardness and the structural stiffness. The subsequent outcome in the development of a portable quality control device to monitor the acceptable moisture content level to ensure flexibility of the clay mats was also described in this paper.

Calibration of Grassmaster II to estimate green and dry matter yield in Mediterranean pastures: effects of pasture moisture content

Accurate assessment of standing pasture biomass in livestock production systems is a major factor for improving feed planning. Several tools are available to achieve this, including the GrassMaster II capacitance meter. This tool relies on an electrical signal, which is modified by the surrounding pasture. There is limited knowledge on how this capacitance meter performs in Mediterranean pastures. Therefore, we evaluated the GrassMaster II under Mediterranean conditions to determine (i) the effect of pasture moisture content (PMC) on the meter’s ability to estimate pasture green matter (GM) and dry matter (DM) yields, and (ii) the spatial variability and temporal stability of corrected meter readings (CMR) and DM in a bio-diverse pasture. Field tests were carried out with typical pastures of the southern region of Portugal (grasses, legumes, mixture and volunteer annual species) and at different phenological stages (and different PMC). There were significant positive linear relations between CMR and GM (r2 = 0.60, P < 0.01) and CMR and DM (r2 = 0.35, P < 0.05) for all locations (n = 347). Weak relationships were found for PMC (%) v. slope and coefficient of determination for both GM and DM. A significant linear relation existed for CMR v. GM and DM for PMC >80% (r2= 0.57, P < 0.01, RMSE = 2856.7 kg ha–1, CVRMSE=17.1% to GM; and r2= 0.51, P < 0.01,RMSE = 353.7 kg ha–1, CVRMSE = 14.3% to DM). Therefore, under the conditions of this current study there exists an optimum PMC (%) for estimating both GM and DM with the GrassMaster II. Repeated-measurements taken at the same location on different dates and conditions in a bio-diverse pasture showed similar and stable patterns between CMR and DM (r2= 0.67, P < 0.01, RMSE = 136.1 kg ha–1, CVRMSE = 6.5%). The results indicate that the GrassMaster II in-situ technique could play a crucial role in assessing pasture mass to improve feed planning under Mediterranean conditions.