Determination Of Water Content Research Articles

Transformation of peat deposits and carbon accumulation in post-pyrogenic raised bogs within the taiga zone of West Siberia

The aim of the study was to assess of the transformation of the hydrologic and physical properties of peat deposits and peat accumulation rates in the post-pyrogenic sites of drained fens in the taiga zone of West Siberia. Location and time of the study. Field studies were conducted in 2022 on the Bakchar fen (drained for forestry, seven plots) and Ust-Bakchar fen (drained for peat extraction, three plots) located in the Tomsk region. Methods. Peat sampling was carried out from two boreholes at each plot in the hollow and the hummock. The sampling increment was 5 cm; the total depth was 45–90 cm. Peat samples were taken at nine subsites by the envelope method on each plot in 0–30 cm layer by 10 cm increment for water content determination in laboratory. Laboratory study of peat characteristics was carried out using the following methods: water and ash content measurements (GOST 11306-2013, GOST 11306-2013), estimation of peat decomposition and humification degree, botanical composition (GOST 28245-89), as well as measuring peat bulk density. Carbon stocks in the upper layer of peat deposits was estimated using the values of peat ash content and density. Results. The peat deposit of the upper layers was formed mainly by sphagnum peat with Sphagnum fuscum plant residues predominating. The differences between hollows and hummocks in their peat properties were manifested to a depth of 5–15 cm from the surface of depressions. The burnout of the hollows led to the changes of all peat properties to a depth of 10–15 cm: the changes were more pronounced in ash content, which was 1.5–9 times higher in the 0–5 cm layer as compared with the unburned site. The changes in peat properties on positive relief forms, i.e. moss hummocks, was less evident in the upper 0–5 cm layer, but reached a greater depth of 30 cm. The change was revealed mainly as an increase in peat ash content due to the migration of ash elements from the surface of burnt hollows and as an increase in bulk density due to subsidence of moss hummocks with the died-off sphagnum moss. Although the average water content in postpyrogenic and unburned sites was the same, amounting to 90–91% in the 0–30 cm layer, some difference was observed between the microrelief forms. The post-pyrogenic site in the Bakchar fen was characterized by water content decrease in hollows and hummocks, the maximum values being observed at an altitude near the average surface. In the Ust-Bakchar fen, water content was found to decrease from hollows to hummocks. In the Bakchar fen, 30 years after the fire peat accumulation occurred only on positive microrelief forms, where the 35 cm thick layer formed after the fire. Taking into account the microrelief heterogeneity, carbon accumulation over the post-fire period was estimated as 1.9 kg C/m2 or 60 g C/m2 per year. Peat accumulation seemed much slower in the Ust-Bakchar fen and was apparently absent on most of the surface. The average rate was estimated as 7 g C/m2 per year. Conclusions. The study found fen hollows to be most prone to burnout. The consequences of the fire manifest themselves in the drying of the upper layer of the peat deposit, thus preventing intensive overgrowth by sphagnum mosses 6–8 years after the fire. At the drained for forestry site in the Bakchar fen, 30 years after the fire the peat accumulation rate on moss hummocks was comparable to the rate in the unburned areas.

Inversion of Leaf Water Content of Cinnamomum camphora Based on Preferred Spectral Index and Machine Learning Algorithm

Plant leaf water content significantly influences photosynthetic efficiency and crop yield. Leaf water content (LWC) and equivalent water thickness (EWT) are indicators that reflect the water state within plant tissues, and they play a crucial role in assessing plant water supply and usage. In recent years, there has been a growing focus on the rapid and precise determination of plant water content. In this study, Cinnamomum camphora (C. camphora) was chosen as the subject of investigation. After acquiring spectral data, three types of vegetation indices were computed: the empirical vegetation index, the random combination dual-band vegetation index, and the ‘trilateral’ parameter. Four groups of optimal spectral index screening strategies were established, namely an empirical vegetation index group (G1), a random combination dual-band vegetation index group (G2), a ‘trilateral’ parameter group (G3), and a mixed group (G4). Three algorithms, specifically random forest (RF), radial basis function neural network (RBFNN), and support vector machine (SVM), were employed for the estimation of leaf water content (LWC) and equivalent water thickness (EWT) in mature C. camphora. The results demonstrated that the G4 group displayed superior performance, yielding five optimal spectral indices for LWC: water index (WI), optimized soil-adjusted vegetation index (OSAVI), difference vegetation index (DVI) at wavelengths 734 and 956 nm, first-order difference vegetation index (DVI-FD) at wavelengths 1009 and 774 nm, and red-edge amplitude (Dr). With regard to EWT estimation, the five optimal spectral indices encompassed the red-edge normalized difference vegetation index (RE-NDVI), simple ratio water index (SRWI), difference vegetation index (DVI) at wavelengths 700 and 1167 nm, first-order difference vegetation index (DVI-FD) at wavelengths 1182 and 1514 nm, and red-edge area (SDr). Utilizing these indices as inputs significantly enhanced the accuracy of the models, with the RF model emerging as the most effective for estimating LWC and EWT in C. camphora. Based on the LWC estimation model of the G4 group and the RF algorithm, the determination coefficient (R2) for both the training and test sets reached 0.848 and 0.871, respectively. The root mean square error (RMSE) was 0.568% for the training set and 0.582% for the test set, while the average relative error (MRE) stood at 0.806% and 0.642%, respectively. Regarding the EWT estimation model, R2 values of 0.887 and 0.919 were achieved for the training and test sets, accompanied by RMSE values of 0.6 × 10−3 g·cm−2 and 0.7 × 10−3 g·cm−2, and MRE values of 3.198% and 2.901%, respectively. These findings lay a solid foundation for hyperspectral moisture monitoring in C. camphora and offer valuable reference for the rapid assessment of crop growth status.

Quantitative Determination of Water in Organic Liquids by Ambient Mass Spectrometry

AbstractThis study uses a rapid tandem mass‐spectrometry method to determine water content in complex organic solutions. Emphasis is placed on trace‐water analysis by a fast and accurate alternative to the Karl–Fischer method. In this new method, water is captured by a charge‐labeled molecular probe. Water binds strongly with high specificity to the strongly electrophilic aldehyde site in a charge‐labelled molecule (N‐methylpyridinium); competitive binding by other analytes is effectively discriminated against in the mass‐measurement step. Quantitative determinations are made over a wide concentration range, 0.001 % (10 ppm) to 99 %, with better than 10 % relative standard deviation, along with short (1 min) analysis times using small sample volumes (several μL). Applications include water measurement in simple organic solvents, for example, deuterated solvents, as well as in complex mixtures, for example, organic reaction mixtures. Additionally, this method allows for water monitoring in levitated droplets. Mechanistic investigations into the impact of water on important chemical processes in organic synthesis and environmental science are reported.

Quantitative Determination of Water in Organic Liquids by Ambient Mass Spectrometry.

This study uses a rapid tandem mass-spectrometry method to determine water content in complex organic solutions. Emphasis is placed on trace-water analysis by a fast and accurate alternative to the Karl-Fischer method. In this new method, water is captured by a charge-labeled molecular probe. Water binds strongly with high specificity to the strongly electrophilic aldehyde site in a charge-labelled molecule (N-methylpyridinium); competitive binding by other analytes is effectively discriminated against in the mass-measurement step. Quantitative determinations are made over a wide concentration range, 0.001 % (10 ppm) to 99 %, with better than 10 % relative standard deviation, along with short (1 min) analysis times using small sample volumes (several μL). Applications include water measurement in simple organic solvents, for example, deuterated solvents, as well as in complex mixtures, for example, organic reaction mixtures. Additionally, this method allows for water monitoring in levitated droplets. Mechanistic investigations into the impact of water on important chemical processes in organic synthesis and environmental science are reported.

Determination of Trace Water Using Fluorescence Probes Based on Nitrogen‐Doped Carbon Quantum Dot Fluorescence Senors (Y‐CDs and R‐CDs)

AbstractIn this work, we reported two nitrogen doped carbon quantum dot fluorescence sensors (Y‐CDs and R‐CDs) with good stability and luminescence efficiency, which can be quickly, sensitively and low‐cost for the determination of trace water content in organic solvents. Using o‐phenylenediamine and p‐phenylenediamine as nitrogen sources and terephthalic acid as carbon sources, the preparation was carried out through simple solvothermal synthesis and heteroatom doping. The luminescence characteristics and interaction mechanism with the target were discussed. The results indicate that the two carbon dots can effectively quench the water content in acetone, ethanol, and DMF, as well as physical interactions such as hydrogen bonding and dynamic quenching, which are the reasons for the observed quenching effect. Based on this, a new method for determining water content in organic solvents using carbon quantum dot fluorescence probes has been established. The linear relationship between the fluorescence quenching efficiency F0/F of two carbon quantum dots and the water content in different organic solvents was studied. The detection limits (LOD) of water in acetone, ethanol and N,N‐dimethylformamide (DMF) were 0.17 %, 2.35 %, 0.26 %, respectively, determined by Y‐CDs. The LOQ of acetone, ethanol, and DMF were 0.554 %, 7.83 %, 0.855 %, respectively. The LOD of water in acetone, ethanol and DMF determined by R‐CDs were 0.056 %, 0.69 %, 0.27 % and the LOQ was 0.187 %, 2.290 %, 0.909 %, respectively. Good recovery rates and precision were achieved in practical applications.

Estimating soil water content in a thorny forest ecosystem by time‐lapse electrical resistivity tomography (ERT) and HYDRUS 2D/3D simulations

AbstractDetermination of soil volumetric water content in forest ecosystems is particularly challenging due to deep rooting systems and unknown soil vertical and spatial heterogeneity. This research aims to test two undisturbed methods, electrical resistivity tomography (ERT) and HYDRUS 2D/3D, for 2D determination in a thorny forest ecosystem. The experiment consisted of infiltrating 10 L of water lasting 60 min. During infiltration, ERT measured apparent resistivity by time‐lapse measurements, and was measured with an FDR probe (EnviroSCAN) at 33, 63, 83, 97, and 163 cm depth close to the infiltration site. At the end of infiltration, a soil pit was dug, and 100 measurements of were performed with a TDR in a 10 × 10 cm regular grid. Archie law transformed soil resistivity (ERT) into using manual calibration, verified by an independent dataset. The 2D profile obtained by ERT was qualitatively compared with the HYDRUS 2D/3D one. HYDRUS 2D/3D was parametrized with calibrated parameters obtained with HYDRUS 1D using 106 days of obtained with EnviroSCAN. The results of HYDRUS 1D calibration and verification were satisfactory, with RMSE and Nash‐Sutcliffe coefficients ranging from 0.021 to 0.034 cm3 cm−3 and 0.11 to 0.77, respectively. The forward HYDRUS 2D/3D simulation disagrees with EnviroSCAN data for 33 cm depth. However, it follows the trend with near to zero variation of water content at 63 cm depth. Water content determination by ERT was satisfactory with RMSE for calibration and verification of 0.017 and 0.021 cm3 cm−3. HYDRUS 2D/3D and ERT comparisons were not equal, with a shallower wetting front by ERT and a deeper one for HYDRUS. Still, both wetting fronts agree with the wetting depth estimated by EnviroSCAN. We conclude that both methods are an alternative for determination in heterogeneous and deep soils of forest ecosystems.

Shannon entropy on near-infrared spectroscopy for nondestructively determining water content in oil palm

<span lang="EN-US">Indonesia is the world’s largest producer of palm oil. To preserve its competitive advantages, the Indonesian oil palm sector must expand high-quality palm oil output. In oil palm quality control, the water content is a crucial parameter as it can be used as a reference to determine the right harvest time. Thus, this study proposed a near-infrared (NIR) spectroscopy as a fast and non-destructive analysis to assess oil palm water content. NIR spectra were processed using Shannon entropy to describe the characteristics at each wavelength. In this study, oil palm fruit samples at various maturity levels were collected with eight different maturity fractions. Based on the analysis, the Shannon entropy value is closely related to any changes in the water content of palm oil. The entropy value has a decreasing trend as the water content increases. The proposed technique can predict the water content of an oil palm with satisfactory performance with values of 0.9746 of coefficient of determination (R<sup>2</sup>) and 2,487 of root mean square error (RMSE). Application of this model will lead to a fast and accurate prediction system related to oil palm water content.</span>

Fast-nondestructive measurement of axial slice water content and water distribution with NMR SFG-MSCPMG sequence

Measuring hydraulic conductivity by instantaneous profile method needs to detect the pore water content of soil at different positions, but most of the detecting methods will disturb the soil sample. In the study, the axial slice scanning of soil samples was carried out by using static filed gradient multi-slice Carr-Purcell-Meiboom-Gill (SFG-MSCPMG) sequence of nuclear magnetic resonance (NMR) technology, which can nondestructively determine water content and distribution at different positions of soil column. In this experiment, three clays were used to illustrate the relationship between NMR test results and oven drying results of water content. The results show that there is a good linear relationship between the NMR signal and water content. Combining mercury intrusion porosimetry (MIP) data, the transverse surface relaxivity parameters (ρ2) of clays are obtained. With ρ2 = 41.90 μm/s the T2 distribution curve of pore water in the ordinary clay can be converted into the pore water distribution curve, which is in good agreement with that obtained with MIP. Nevertheless, it is found that the T2 distribution curve of pore water in expansive clay obtained with NMR technique is more suitable for analyzing the average pore water distribution because of the fast exchange of pore water between the interlayers, intra-aggregates and inter-aggregates in expansive clay.

Polymer Microtip-Based Fabry-Perot Interferometer for Water Content Determination in the Gas and Liquid Phase.

In this work, we present a Fabry-Perot interferometer (FPI) based on a polymer microtip for water content determination in both the gas and liquid phase. The polymer tip of pentaerythritol triacrylate (PETA) is fabricated at the end of an optical fiber by self-guiding photopolymerization, forming at the same time a low-fineness Fabry-Perot interferometer and a sensing layer for water thanks to hydroxyl groups present in PETA. The PETA tip shows a clear interferometric signal, which is highly sensitive to the change of the water content in the environment. The FPI signal shifts with a constant sensitivity of 90 pm/%RH, which corresponds to a relative sensitivity of 104 ppm/% RH, in the range of relative humidity from 30 to 80%. In liquid, the FPI sensor shows a nonlinear sensitivity, up to 158 pm/wt % as the water content is below 40 wt % in water/glycerol mixtures. The cross effect of the temperature on the PETA tip is demonstrated to be negligible as the FPI signal is insensitive to temperature changes from 23 to 70 °C. More importantly, the interaction between the tip and the environment affecting the FPI signal is demonstrated experimentally. The proposed FPI sensor is therefore promising for the direct, sensitive, and reliable determination of the water content of products.

Leaf water content determination of oilseed rape using near-infrared hyperspectral imaging with deep learning regression methods

Water content is crucial for plant growth. Determination of water content can help monitor plant growth status. In this study, spectral data in the range of 900–1700 nm acquired by near-infrared hyperspectral imaging and corrected by black-white calibration were used to detect the water content of fresh oilseed rape leaves. The oilseed leaves were analyzed without particular treatments. Conventional machine learning (support vector regression, partial least squares regression and least absolute shrinkage and selection operator) and deep learning regression models (Convolutional Neural Network and Long Short-Term Memory) were developed to predict oilseed rape leaf water content. The performance of CNN-LSTM-R was highly accurate. The coefficient of determination and root mean square error of the testing set (RMSEP) were 0.814 and 0.005, respectively. The characteristic wavelengths with strong correlation with water content prediction of the regression models were analyzed. The results showed that the deep learning-based regression models showed great potential for water content determination of oilseed rape leaves. Therefore, this study provides an important theoretical basis and practical application for the detection of fresh plant water content.

Environmentally friendly method in determining the water content of coffee by NIR Spectroscopy

Coffee quality could be determined from several aspects, one of those is the water content inside. Along the storage, it must be low and for coffee export it must be below 12.5%. Nowadays, the determination of water content is conducted by the chemical method like the gravimetry method which spend time, destructive also can not represent all of the products. Therefore, it is not in line with the industries which need an actual measurement that could measure all of the products nondestructively and also keep considering the environment. This study aimed to develop a PLS model to determine the water content of green bean coffee, nondestructively. This study used green bean coffee from several region in Indonesia with a high range data concentration (7.18% - 12.16%), a NIR wavelength of 1000-2500 nm, followed by determination of water content using gravimetry method. After that, the NIR data was processed using data pretreatment such as normalization, first derivative, second derivative, multiple scatter correction and standard normal variate and followed by the calibration using PLS and validation. Result showed that NIR spectroscopy could be used to calculate the percentage of water inside coffee beans, indicated by high R value above 0.8% and high consistency above 90%.

Determination of the water content of an ex vivo porcine liver

Abstract When modeling High-Frequency (HF) surgical applications the choice of the right dielectric tissue parameters is a key factor for success. The water content of biological tissue is of particular importance since the dielectric tissue properties highly depend on it. Therefore, we investigate a simple and fast method for the determination of relative tissue water content using small samples of an ex vivo porcine liver. To identify the water content, we utilized a desiccation and weighing experiment. It is assumed that the weight loss can be directly attributed to the loss of water in the case of desiccation. Based on the ratio between the initial and dry weight of a sample, the relative water content can be determined. The drying procedure lasted 28 hours, with 16 small samples taken from an ex vivo porcine liver. At the end of the drying procedure, a relative tissue water content of 69.6 % ± 1.1 % was observed. Using a curve fit to the measured data, it can be assumed that approximately 99.3 % of the tissue water content had evaporated by the end of the drying process. With the drying and weighing method used, we were able to determine the water content of the ex vivo porcine liver relatively easily. However, our results also suggest that optimizations of the applied method should be considered for future measurements. Especially, if a faster determination of the water content is required, which in a broader sense should afterward serve for the validation of a simulation model.

Effects of Freeze–Thaw Cycles on the Mechanical Properties and Microstructure of a Dispersed Soil

Dispersed soil is highly sensitive to water and can easily disperse in low-salt water, leading to weakened structures and engineering issues. To investigate the freeze–thaw effects on the mechanical properties and microstructure of dispersed soils in western Jilin Province, we simulated 0, 1, 3, 5, 7, 9, 12, and 15 freeze–thaw cycles. Qualitative and quantitative analyses were performed using numerous methods, including soluble salt determination, density and water content determination, particle size analysis, dispersion identification tests, and scanning electron microscopy (SEM), to investigate the mechanism of deterioration in soil mechanical properties from various perspectives. The research findings indicate that the unconfined compressive strength (UCS) decreased from 156.843 kPa in the unfrozen state to 76.961 kPa and then stabilized. The freeze–thaw action resulted in particle fragmentation, increased soil porosity, and elevated crack content, thereby contributing to soil structure deterioration and strength reduction. Furthermore, the cohesion value (c-value) gradually decreased from 22.196 kPa in the unfrozen state to 7.997 kPa and then stabilized. The angle of internal friction (φ-value) started at 7.514°, peaked at 9.514°, and gradually declined. This comprehensive study provides valuable insights into the variations in soil mechanical properties under freeze–thaw cycles from multiple perspectives.

A Sustainable Way to Determine the Water Content in Torreya grandis Kernels Based on Near-Infrared Spectroscopy

Water content is an important parameter of Torreya grandis (T. grandis) kernels that affects their quality, processing and storage. The traditional drying method for water content determination is time-consuming and laborious. Water content detection based on modern analytical techniques such as spectroscopy is accomplished in a fast, accurate, nondestructive, and sustainable way. The aim of this study was to realize the rapid detection of the water content in T. grandis kernels using near-infrared spectroscopy. The water content of T. grandis kernels was measured by the traditional drying method. Meanwhile, the corresponding near-infrared spectra of these samples were collected. A quantitative water content model of T. grandis kernels was established using the full spectrum after 10 outlier samples were removed by the Mahalanobis distance method and concentration residual analysis. The results showed that the prediction model developed from the partial least squares regression (PLS) method after the spectra were pretreated by the standard normal variate transform (SNV) achieved optimal performance. The correlation coefficient of the calibration set (R2c) and the cross-validation set (R2cv) were 0.9879 and 0.9782, respectively, and the root mean square error of the calibration set (RMSEC) and the root mean square error of the cross-validation set (RMSECV) were 0.0029 and 0.0039, respectively. Thus, near-infrared spectroscopy is feasible for the rapid nondestructive detection of the water content in T. grandis seeds. Detecting the water content of agricultural and forestry products in such an environmentally friendly manner is conducive to the sustainable development of agriculture.

Nanoformulation of lipase from Porcine pancreas by electrospinning as a novel alternative for enzyme-based per os therapies

Pancreatic enzyme replacement therapy (PERT) treats pancreatic insufficiency, causing a lack of digestive enzymes due to pancreatic damage or dysfunction. However, traditional PERT faces challenges such as poor stability and limited efficiency of the enzymes. Lipase from Porcine pancreas (PpL) is commonly applied for PERT, however only classic formulas such as tablets or capsules produced from physical mixture of the enzyme and excipients had been developed. Electrospinning produces nanofibers that are promising as drug carriers, due to their high surface area-to-volume ratio and tunable physicochemical properties. In this study we investigated the direct nanoformulation of PpL applying polymer nanofibers. The effect of water-soluble and water-resist polymers (PVA: polyvinyl alcohol, PVP: polyvinylpyrrolidone and PLA: polylactic acid) on the physicochemical properties of precursor for electrospinning and on the nanofibers produced from them was systematically investigated. The immobilization of PpL using electrospun nanofibers by entrapment and adsorption methods was developed and compared the enzymatic activities of the nanofibrous formulas. It was found that immobilization using nanofibers in all cases caused a large increase in the enzymatic activity of PpL. Our research demonstrates that nanoformulation of PpL could be efficient by electrospinning technique and the polymer has dominant effect on the enzymatic and structural properties of formulas since PpL entrapped in PLA showed the highest enzymatic activity. Nanofibrous enzyme loaded formulations were comprehensively studied by rheology, scanning electron (SEM) and Raman microscopy, water content determination, positron annihilation lifetime spectroscopy (PALS) and enzyme activity assay of ester hydrolysis.

Experimental Study on Solidified Lake Sediment Based on Industrial Solid Waste and Construction Waste: Stabilization and Mechanism

Occupation of land and damage to the surrounding ecosystem may occur due to the accumulation of dredged lake sediments. In order to solve the large amount of dredged lake sediments, industrial wastes (slag, desulfurization gypsum) and urban construction waste were used to solidify the lake substrate, obtained a new construction material. Water content, volumetric shrinkage, unconfined compressive strength and flexural strength parameters and hydraulic conductivity coefficients of the solidified sediment were obtained from water content determination tests, volumetric shrinkage tests, unconfined compressive strength tests, flexural tests and permeation tests. Mineralogical composition and microstructural characterization of the solidified sediment using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were obtained. The solidification mechanism of lake sediment under the coupling of industrial waste and urban construction waste was revealed. The water content of the specimens decreased rapidly, and shrinkage deformation occurred in curing for 7 d. The volumetric shrinkage of 28 d was eventually maintained at 1.27–5.19%. The trend of specimen strength changed with the extension of time in the overall increase state, the compressive strength and flexural strength within 28 d were 3.15–10.96 MPa and 0.64–2.69 MPa, respectively. The solidified sediment material showed excellent anti-seepage performance, the hydraulic conductivity reached stability at 1.22 × 10−8–55.4 × 10−8 cm/s. Gismondine, gypsum, calcite, scawtite and fibrous C-S-H phases were generated in the solidified material.

Determination of refractive index increments of PMMA particles dispersed in liquid phase

The refractive index increments of poly(methyl methacrylate) (PMMA) particles with sizes ranging from submicron to several microns were determined by measuring different concentrations of the solution and using a refractometer and microbalance calibrated by accurate traceability source. Conventionally, it was common to measure only the difference in refractive index between solvent and solution using a Bryce-type cell system, but it is difficult to perform traceable calibration since there is no reference material for refractive index increment. In this paper, we accurately quantify the refractive index increment by making individual measurements of the solvent and solution refractive indices, respectively, using Abbe-type refractometer. In addition, an uncertainty analysis was performed, and the results clarified the main factor of the variance in the refractive index increment measurements. The most important factor of variation of refractive index increment measurement is the measured apparent values at dilute concentration region including fluctuation of the system. This method was able to be applied to the determination of water content existing in particles. The percentage of the water content was determined using two different solvents, and the water content values were in good agreement within their uncertainties.

Paper-based sensor based on lead-free manganese halide for the determination of water content in organic solvents.

A highly stable and luminescent lead-free manganese(II) halide hybrid MnBr4(TMN)2 (C34H42Br4MnN4) was designed and synthesized by introducing a large cationic organic spacer. The MnBr4(TMN)2 displays high luminescence with quantum yields up to 77% and possesses turn-off fluorescence behavior (Ex/Em=365/546 nm) for water. These properties make the MnBr4(TMN)2 a promising candidate as an alternative indicator for the detection of water with potential applications for the fabrication of LEDs. Herein, a paper-based sensor based on MnBr4(TMN)2 is described for the determination of water content in organic solvents. The mechanism of water sensing can be tentatively explained by fluorescence quenching originating from the destruction of water dueto the Mn-Br bonds of MnBr4(TMN)2. The MnBr4(TMN)2-based paper sensor exhibits an excellent discrimination ability of water content in therange 0-25.0% with a detection limit of 0.27%. Satisfactory recoveries (94.91±4.09% to 103.23±2.38%) are obtained in spiked ethanol solvent samples, which demonstrate that the MnBr4(TMN)2-based paper sensor is capable of detecting water content in real ethanol solvent samples.

DETERMINATION OF WATER CONTENT IN GRAINS WITH MICROWAVE OVEN

The determination of water content is essential for the maintenance of grain quality, and an evaluation of alternative methods for quantification allows to increase the efficiency of the process and bring benefits to the productive sector. The study aimed to analyze the efficiency of using microwave ovens to determine the water content in grains. The study was carried out in a completely randomized design in a 5 x 6 factorial scheme, with five species (peanut, sunflower, corn, soybean and wheat) and six microwave drying periods (0.5, 1, 1.5, 2, 2.5, and 3 min), with four replications. Data were subjected to descriptive analysis to characterize the samples, and regression analysis to analyze differences between methods as a function of drying time. The determination of water content in peanut, sunflower, corn, soybean and wheat grains in microwave is technically feasible, showing correlation with the determination in an oven by the standard method. The drying time in the microwave influences the water removal capacity of the grains. For peanut, sunflower, corn, soybean and wheat grains, the microwave drying time of 3 min showed greater similarity with the determination by the standard method.

Calorimetric determination of wet snow liquid water content: The effect of test conditions on the calorimeter constant and its impact on the measurement uncertainty

The liquid water content (lwc) of wet snow is a fundamental parameter in determining snow properties like its strength and adhesion force to surfaces. Among the different methods available for the measurement of the lwc, this paper focuses on melting calorimetry: known masses of hot water and snow are mixed into a thermally insulated container, and the lwc is obtained from the difference between the initial hot water temperature and the final mixing temperature; it is a fast and easy to implement method that requires little equipment, making it suitable for both laboratory and field measurements. Tests with “equivalent” wet snow samples whose liquid water content was known in advance were carried out to assess the method, showing that the liquid water content was overestimated by a variable amount that seemed to depend on the test parameters. To account for the heat capacity of the calorimeter, which was found not to be negligible, a constant in terms of equivalent hot water mass (E) was introduced. However, its value also depended on the test conditions. Hence, a correlation between E and the test parameters was found, and the measurements were repeated using a container of a different material, showing a similar behavior. Eventually, a discussion about the effects of choosing different hot water masses and hot water-to-snow mass ratios on measurement accuracy is provided.