Determination Of Water Content Research Articles

KARAKTERISASI SIMPLISIA DAN EKSTRAK KULIT BATANG SEKILANG (Embelia borneensis Scheff.)

The Sekilang plant (Embelia borneensis Scheff.) Is one of the plants used by the Dayak community for fishing, leech repellent and as an ingredient for hair care. Empirical use of plants can be developed into products based on natural ingredients. This must be supported by research data. As a first step, the simplicia and ethanol extract of the stem bark were characterized. The research objective was to determine the specific and non-specific characteristics of the simplicia and the extracts of the bark of the sekilang. The research stage includes plant determination, collection of raw materials, manufacture of simplicia, extract preparation, organoleptic, microscopic testing, phytochemical screening, determination of water soluble extract content, determination of ethanol soluble extract content, determination of water content and determination of ash content. Microscopy test results of sekilang stem bark showed the presence of fiber fragments, stone cells, and oxalate crystals. The average water soluble content for simplicia and sekilang bark extract was 7.5% and 80%. The average ethanol soluble content for simplicia and extract was 6% and 30%. The average moisture content for the simplicia and extract was 9.5% and 12%. The mean total ash content for simplicia and extract was 5% and 8.5%. The mean acid insoluble ash content for simplicia and extract was 1% and 0.5%.

A simple method for estimating the optimum water content for tillage

AbstractSimple and quick determination of the optimum water content for tillage (θOPT) is helpful to guide tillage operations. Based on the definition of θOPT that is the water content at the inflection point of the soil water retention curve, a simple method was established to estimate the θOPT from saturated water content (θs) (θOPT = 0.75θs). The validation results on 132 soils with varying texture showed that the root mean squared error and mean error were 0.021 and 0.009 g g−1, respectively. These results confirmed that the θs was valuable information for estimating θOPT and the proposed method could give a reasonable estimation for θOPT.

Quantification and characterization of water within drug-eluting beads

This work describes the analysis and characterisation of polyvinylalcohol (PVA)-based hydrogel polymer beads, specifically focussing on the quantitative and qualitative aspects of water within such beads in the absence and presence of three drugs; doxorubicin and irinotecan (already utilised as medicines) and finally, imipramine (for comparison). Using optical microscopy the size of the beads in the presence of increasing amounts of imipramine decreased (121–79 μm) as water was displaced, demonstrating the presence of drug-bead interactions. Thermogravimetric analysis (TGA) permitted determination of the total water content within the beads, ranging from beads alone that contained 96.8% water, through to beads formulated with irinotecan that contained only 91.7% water. Differential scanning calorimetry (DSC) was utilised to investigate water present within their hydrogel structures, separated into bound (non-freezing), loosely bound and unbound forms. For imipramine and irinotecan (25 mg/mL) beads there was little impact on the relative ratio of bound, loosely bound and free water within the structure. For doxorubicin and the higher drug loaded irinotecan a distinct decrease in overall water content was seen. This study confirms the ability of TGA and DSC to characterise the differing types of water within the beads and indicates the relative changes in water content in the presence of these three drugs. It is clearly beneficial to characterise states of water in such hydrogel systems to better understand drug loading and release in the context of cancer treatment.

Gaussian process regression to determine water content of methane: Application to methane transport modeling

The uncontrolled release of methane from natural gas wells may pose risks to shallow groundwater resources. Numerical modeling of methane migration from deep hydrocarbon formations towards shallow systems requires knowledge of phase behavior of the water-methane system, usually calculated by classic thermodynamic approaches. This study presents a Gaussian process regression (GPR) model to estimate water content of methane gas using pressure and temperature as input parameters. Bayesian optimization algorithm was implemented to tune hyper-parameters of the GPR model. The GPR predictions were evaluated with experimental data as well as four thermodynamic models. The results revealed that the predictions of the GPR are in good correspondence with experimental data having a MSE value of 3.127 × 10−7 and R2 of 0.981. Furthermore, the analysis showed that the GPR model exhibits an acceptable performance comparing with the well-known thermodynamic models. The GPR predicts the water content of methane over widespread ranges of pressure and temperature with a degree of accuracy needed for typical subsurface engineering applications.

Fast and non-destructive determination of water content in ionic liquids at varying temperatures by Raman spectroscopy and multivariate regression analysis

Imidazolium acetate ionic liquids (ILs) have been utilized as promising solvents in many applications that involve varying water content and temperature. These experimental variables affect the anion-cation intermolecular interactions, which in turn influence the performance of the ILs in these applications. This paper shows Raman spectroscopy can be used as an operando method to measure water content in IL solvents when simultaneous temperature changes may occur. The Raman spectra of 1-alkyl-3-methylimidazolium acetate ILs (alkyl chain length n = 2, 4, 6, 8) with varying water content (from 0.028 to 0.899 water mole fraction) and temperature (from 78.1 K to 423.1 K) were measured. Increasing the water content or decreasing the temperature of the tested ILs weakens the anion-cation intermolecular interactions. The water content of these ILs can be quantified even in conditions when the temperature is changing using Raman spectroscopy combined with multivariate regression analysis, including principal component regression (PCR), partial-least-squares regression (PLSR), and artificial neural networks (ANNs). The ANN model combined with partial-least-squares (PLS) achieved the highest prediction accuracy of water content in ILs at varying temperatures (RMSECV = 0.017, R2CV = 99.1%, RMSEP = 0.019, R2P = 98.8%, RPD = 8.93). Raman spectroscopy provides a potential fast non-destructive operando method to monitor the water content of ILs even in applications when the temperature may be simultaneously altered; this information can lead to the optimized use of these ILs in many applications.

Hysteresis in the ultrasonic parameters of saturated sandstone during freezing and thawing and correlations with unfrozen water content

Determining the mechanical properties of frozen rock is highly important in cold-area engineering. These properties are essentially correlated with the content of liquid water remaining in frozen rock. Therefore, accurate determination of unfrozen water content could allow rapid evaluation of mechanical properties of frozen rock. This paper investigates the hysteresis characteristics of ultrasonic waves applied to sandstone (in terms of the parameters of P-wave velocity, amplitude, dominant frequency and quality factor Q ) and their relationships with unfrozen water content during the freeze-thaw process. Their correlations are analysed in terms of their potential for use as indicators of freezing state and unfrozen water content. The results show that: (1) During a freeze-thaw cycle, the ultrasonic parameters and unfrozen water content of sandstone have significant hysteresis with changes in temperature. (2) There are three clear stages of change during freezing: supercooled stage (0 °C to −2 °C), rapid freezing stage (−2 °C to −3 °C), and stable freezing stage (−3 °C to −20 °C). The changes in unfrozen water content and ultrasonic parameters with freezing temperature are inverse. (3) During a single freeze-thaw cycle, the ultrasonic parameters of sandstone are significantly correlated with its unfrozen water content, and this correlation is affected by the pore structure. For sandstones with mesopores greater than 50%, there are inflection points in the curves of ultrasonic parameters vs. unfrozen water content at −3 °C during freezing and at −1 °C during thawing. It was found that thermal deformation of the mineral-grain skeleton and variations in the phase composition of pore water change the propagation path of ultrasonic waves. The inflection point in the curve of dominant frequency vs. temperature clearly marks the end of the rapid freezing stage of pore water, in which more than 70% of the pore water freezes. Consequently, the dominant frequency can be used as an index to conveniently estimate the unfrozen water content of frozen rock and, hence, its mechanical properties.

Magma chamber decompression during explosive caldera-forming eruption of Aira caldera

Decompression of a magma chamber is a fundamental condition of caldera collapse. Although theoretical models have predicted the decompression of magma chambers before caldera collapse, few previous studies have demonstrated the amount of magma chamber decompression. Here, we determine water content in quartz glass embayments and inclusions from pyroclastic deposits of a caldera-forming eruption at Aira volcano approximately 30,000 years ago and apply this data to calculate decompression inside the magma chamber. We identify a pressure drop from 140–260 MPa to 20–90 MPa during the extraction of around 50 km3 of magma prior to the caldera collapse. The magma extraction may have caused down-sag subsidence at the caldera center before the onset of catastrophic caldera collapse. We propose that this deformation resulted in the fracturing and collapse of the roof rock into the magma chamber, leading to the eruption of massive ignimbrite.

In Situ Water Quantification in Natural Deep Eutectic Solvents Using Portable Raman Spectroscopy

Raman spectroscopy is a label-free, non-destructive, non-invasive analytical tool that provides insight into the molecular composition of samples with minimum or no sample preparation. The increased availability of commercial portable Raman devices presents a potentially easy and convenient analytical solution for day-to-day analysis in laboratories and production lines. However, their performance for highly specific and sensitive analysis applications has not been extensively evaluated. This study performs a direct comparison of such a commercially available, portable Raman system, with a research grade Raman microscope system for the analysis of water content of Natural Deep Eutectic Solvents (NADES). NADES are renewable, biodegradable and easily tunable “green” solvents, outcompeting existing organic solvents for applications in extraction from biomass, biocatalysis, and nanoparticle synthesis. Water content in NADES is, however, a critical parameter, affecting their properties, optimal use and extraction efficiency. In the present study, portable Raman spectroscopy coupled with Partial Least Squares Regression (PLSR) is investigated for rapid determination of water content in NADES samples in situ, i.e., directly in glassware. Three NADES systems, namely Betaine Glycerol (BG), Choline Chloride Glycerol (CCG) and Glucose Glycerol (GG), containing a range of water concentrations between 0% (w/w) and 28.5% (w/w), were studied. The results are directly compared with previously published studies of the same systems, using a research grade Raman microscope. PLSR results demonstrate the reliability of the analysis, surrendering R2 values above 0.99. Root Mean Square Errors Prediction (RMSEP) of 0.6805%, 0.9859% and 1.2907% w/w were found for respectively unknown CCG, BG and GG samples using the portable device compared to 0.4715%, 0.3437% and 0.7409% w/w previously obtained by analysis in quartz cuvettes with a Raman confocal microscope. Despite the relatively higher values of RMSEP observed, the comparison of the percentage of relative errors in the predicted concentration highlights that, overall, the portable device delivers accuracy below 5%. Ultimately, it has been demonstrated that portable Raman spectroscopy enables accurate quantification of water in NADES directly through glass vials without the requirement for sample withdrawal. Such compact instruments provide solvent and consumable free analysis for rapid analysis directly in laboratories and for non-expert users. Portable Raman is a promising approach for high throughput monitoring of water content in NADES that can support the development of new analytical protocols in the field of green chemistry in research and development laboratories but also in the industry as a routine quality control tool.

Experimental Study of Site-Specific Soil Water Content and Rainfall Inducing Shallow Landslides: Case of Gakenke District, Rwanda

Shallow landslides are among the natural threats causing death and damage. They are mostly triggered by rainfall in mountainous areas where precipitation used to be abundant. The amount of rainfall inducing this natural threat differs from one site to another based on the geographical characteristics of that area. In addition to the rainfall depth, the determination of soil water content in a specific zone has a major contribution to the landslide prediction and early warning systems. Rwanda being a country with hilly terrains, some areas are susceptible to both rainfall and soil water content inducing landslides. But an analytical study of the physical threshold determination of both rainfall and soil water content inducing landslides is lacking. Therefore, this experimental study is conducted to determine the rainfall and soil water content threshold that can be fed in to the landslide early warning system (LEWS) for alert messages using the Internet of Things (IoT) technology. Various experiments have been conducted for the real-time monitoring of slope failure using the toolset composed of a rain gauge, soil moisture sensors, and a rainfall simulating tool. The results obtained show that the threshold for landslide occurrence does not solely correlate with the total rainfall amount (or intensity) or soil moisture, but also influenced by internal (geological, morphological) and environmental factors. Among the sampled sites, the sites covered by forest indicated no sign of slope failure, whereas sites with crops could slip. The experiments revealed that for a specific site, the minimum duration to induce slope failure was 8 hours, 41 minutes with the rainfall intensity of 8 mm/hour, and the soil moisture was above 90% for deeper sensors. These values are used as thresholds for LEWS for that specific site to improve predictions.

Filter paper method for suction measurement using electrical resistivity

The filter paper method is an economical, easily accessible, and simple-to-use method to measure total or matric suction over a wide suction range. Difficulty in handling the filter paper can result in inaccurate water content determination of the filter paper leading to poor estimation of the suction. This paper examines the feasibility of using electrical resistivity of the filter paper in the non-contact mode to determine equilibrium time and to infer the total suction. It was shown that for a specific set-up, electrical resistance (ER) can be used in place of electrical resistivity. Relationships between ER and water content of the filter paper and between ER and total suction were first established. Finally, a prototype set-up is used to demonstrate how it can be used to measure the total suction of soil specimens. It was demonstrated that ER of the filter paper can be used to provide a reasonable estimate of total suction greater than 100 kPa with an error between −18 and +10%. Better accuracy can be achieved if each filter paper is calibrated before use.

Rapid determination of leaf water content for monitoring waterlogging in winter wheat based on hyperspectral parameters

Waterlogging is becoming an obvious constraint on food production due to the frequent occurrence of extremely high-level rainfall events. Leaf water content (LWC) is an important waterlogging indicator, and hyperspectral remote sensing provides a non-destructive, real-time and reliable method to determine LWC. Thus, based on a pot experiment, winter wheat was subjected to different gradients of waterlogging stress at the jointing stage. Leaf hyperspectral data and LWC were collected every 7 days after waterlogging treatment until the winter wheat was mature. Combined with methods such as vegetation index construction, correlation analysis, regression analysis, BP neural network (BPNN), etc., we found that the effect of waterlogging stress on LWC had the characteristics of hysteresis and all waterlogging stress led to the decrease of LWC. LWC decreased faster under severe stress than under slight stress, but the effect of long-term slight stress was greater than that of short-term severe stress. The sensitive spectral bands of LWC were located in the visible (VIS, 400–780 nm) and short-wave infrared (SWIR, 1 400–2 500 nm) regions. The BPNN Model with the original spectrum at 648 nm, the first derivative spectrum at 500 nm, the red edge position (λr), the new vegetation index RVI (437, 466), NDVI (437, 466) and NDVI’ (747, 1 956) as independent variables was the best model for inverting the LWC of waterlogging in winter wheat (modeling set: R2=0.889, RMSE=0.138; validation set: R2=0.891, RMSE=0.518). These results have important theoretical significance and practical application value for the precise control of waterlogging stress.

Frequency Dielectric Response of Aramid Enhanced Cellulose Paper in Aspect of Its Water Content Determination

Wydawnictwo SIGMA-NOT wydaje czasopisma fachowe informujące swoich czytelników o najnowszych osiągnięciach naukowych i nowoczesnych rozwiązaniach technicznych w Polsce i na świecie, popularyzuje problemy techniczne oraz poszerza wiedzę i kulturę techniczną.

Two Crystal Forms of a Hydrated 2:1 β-Cyclodextrin Fluconazole Complex: Single Crystal X-ray Structures, Dehydration Profiles, and Conditions for Their Individual Isolation

Inclusion complexes between cyclodextrins (CDs) and active pharmaceutical ingredients (APIs) have potential for pharmaceutical formulation. Since crystallization of a given complex may result in the isolation of multiple crystal forms, it is essential to characterize these forms with respect to their structures and physicochemical properties to optimize pharmaceutical candidate selection. Here, we report the preparation and characterization of two crystallographically distinct hydrated forms of an inclusion complex between β-cyclodextrin (β-CD) and the antifungal API fluconazole (FLU) as well as temperature–concentration conditions required for their individual isolation. Determination of crystal water contents was achieved using thermoanalytical methods. X-ray analyses revealed distinct structural differences between the triclinic (TBCDFLU, space group P1) and monoclinic (MBCDFLU, space group C2) crystal forms. Removal of the crystals from their mother liquors led to rapid dehydration of the MBCDFLU crystal, while the TBCDFLU crystal was stable, a result that could be reconciled with the distinct packing arrangements in the respective crystals. This study highlights (a) the importance of identifying possible multiple forms of a cyclodextrin API complex and controlling the crystallization conditions, and (b) the need to characterize such crystal forms to determine the extent to which their physicochemical properties may differ.

Distribution and migration of moisture in round bamboo in response to microwave drying

Characterized by its light weight, high strength, and good flexibility, round bamboo is a natural functional biomaterial with a multi-level structure. Cracking is a key factor hindering its wider application. Moisture changes cause cracking when the round bamboo is dried. Therefore, studying moisture variations in the drying process of round bamboo can effectively reduce or solve the cracking problem. In this study, microwave drying with computer tomography (CT) imaging technology was used to understand the distribution and migration of moisture in round bamboo in the course of drying. The results indicated that water content has a significant correlation with the CT value, which can be used to achieve rapid determination of water content. The radial water content of samples gradually decreased from bamboo green (outer) to bamboo yellow (inner). The axial water content was high in the middle and low on both ends. As the water content decreased, the axial moisture distribution was consistent. The internode moisture mainly moved from the junction of bamboo yellow and bamboo partition, entered the adjacent cavity, and then gradually moved outward. Thus, the microwave drying method can effectively achieve industrial drying of round bamboo and prevent cracking.

Characteristics of simplicia ginger (Zingiber officinale) and lemongrass (Cymbopogon citratus) powder by different drying method

This study aimed to produce qualified simplicia of ginger and lemongrass powder by determining water content, antioxidant activity, and the characteristic of color and aroma. Two stages of drying were conducted, namely, the conventional method using open-air sun drying and the oven method with a temperature of 50°C for 24 hours. The method used to determine water content was based on SNI 01-2891-1992, and antioxidant activity was determined using the UV. VIS spectrophotometry method. The data were analyzed according to descriptive analysis. The results indicated that the simplicia ginger and lemongrass powder in the oven drying method resulted in lower moisture content, higher antioxidant activity, stronger aroma quality, and lighter color compared to the conventional drying. The water content of ginger and lemongrass powder was 6.75% and 7.2% in oven drying, while the conventional methods were 7.25% and 10.15%, respectively. The antioxidant activity of ginger and lemongrass powder in oven drying was 65.12% and 51.63%, while the conventional methods were 62.41% and 50.05%, respectively. Based on this study, it can be concluded that the simplicia of ginger and lemongrass powder indicated the better characteristics and quality with the oven drying method at 50°C for 24 hours compared to the conventional method using open-air sun drying.

Optimization of the water determination conditions by coulometric titration with evaporation for lubricating oils

The knowledge of the water content of various petroleum products, including lubricating oils, additives and various innovative products, is important from the point of view of manufacturing, purchasing or selling them, due to the impact on their quality and performance characteristics. In the case of lubricating oils, the presence of water can lead to premature corrosion and wear, the formation of deposits, which leads to reduced lubrication and premature clogging of filters, reduced action of additives or undesirable bacterial growth. The article presents the study on the selection of optimal conditions for the determination of water content by coulometric Karl-Fischer titration with evaporation in lubricating oils. The tests were carried out using a coulometer with a titration cell without a diaphragm by Metrohm, 917 Coulometer model with an automatic sample feeder equipped with a heating chamber 885 Compact Oven Sample Changer. Various types of lubricating oils were selected for testing, namely engine oils of different viscosity classes (5W/40, 10W/40, 15W/40, 5W/30), gear oil, hydraulic oil, turbine oil, base oil and hydraulic fluid. All selected samples of lubricating oils were tested in four different measuring conditions: 110°C and 20 ml/min; 150°C and 50 ml/min, 180°C and 50 ml/min and 150°C and 70 ml/min. It was found that for all the lubricating oils, the best results were obtained with a furnace temperature setting of 150°C and a carrier gas flow of 50 ml/min or 70 ml/min. The influence of various factors, such as the sample weight, the furnace temperature, the carrier gas flow velocity on the test course and the analysis speed, was determined. Increased carrier gas flow of up to 70 ml/min does not shorten the analysis time. In some cases, an increase in the oven temperature may speed up the analysis, but this is quite risky for some samples that decompose at given temperature. It is therefore safer to conduct the test at an oven temperature of 150°C. The speed of analysis is most influenced by an appropriate selection of the sample quantity under analysis. Depending on the water content in the tested sample, the appropriate sample weight should be selected. It should be small enough not to excessively extend the analysis, but also large enough that the amount of titrated water is at least twice as large as in the blank.

Method for Determining Water Content in Natural Rhyolitic Melts by Raman Spectroscopy and Electron Microprobe Analysis

Method for Determining Water Content in Natural Rhyolitic Melts by Raman Spectroscopy and Electron Microprobe Analysis

Time-domain NMR analysis for the determination of water content in pharmaceutical ingredients and wet granules

The application of time-domain NMR (TD-NMR) analysis to quantify water content in pharmaceutical ingredients is demonstrated. The initial phase of the study employed a range of disintegrants with defined amounts of added water (0–30% of the total weight) as samples; the disintegrants included croscarmellose sodium, corn starch, low-substituted hydroxypropyl cellulose, and crospovidone. After acquisition of the T2 relaxation curves of the samples by TD-NMR measurements, these curves were analyzed by partial least squares (PLS) regression. According to the analysis, accurate and reliable PLS models were created that enabled accurate assessment of water content in the samples. A powder blend consisting of acetaminophen (paracetamol) and tablet excipients was also examined. Both a physical mixture of the powder blend and a wet granule prepared with a high-speed granulator were tested as samples in this study. Precise determination of water content in the powder blend was achieved by using the TD-NMR method. The accuracy of water content determination was equivalent to or better than that of the conventional loss on drying method. TD-NMR analysis samples were measured nondestructively and rapidly with low cost; thus, it could be a powerful quantitative method for determining water content in pharmaceuticals.

Potential of invasive alien species Clidemia hirta as antibacterial against Salmonella typhi and Staphylococcus aureus

Abstract. Pratami MP, Fendiyanto MH, Satrio RD, Widana IDKK, Nikmah IA, Sari NIP, Awwanah M, Farah N, Darmadi D. 2021. Potential of invasive alien species Clidemia hirta as antibacterial against Salmonella typhi and Staphylococcus aureus. Biodiversitas 22: 3363-3369. Clidemia hirta D. Don is an invasive alien species (IAS) that is a threat to biodiversity in tropical country particularly Indonesia, and remains underutilized to date. Conversely, prevalence of typhus in Indonesia is generally higher every year. Thus, the aim of this study was to detect phytochemicals in ethanolic and aqueous extracts of C. hirta and their antibacterial activity against Salmonella typhi and Staphylococcus aureus. The research methods included sample identification, generating the simplicia, determination of water content, extraction, phytochemical screening tests, and antibacterial activity tests. Identification was made based on morphological characteristics. The water content in the dried powder of simplicia was 12.26 ± 0.39%. Phytochemical results showed that 70% ethanol extract of C. hirta contained flavonoids, saponins, tannins, and triterpenoids compounds. In addition, aqueous extract of C. hirta showed positive results on flavonoids, saponins, tannins, and steroids tests. Antibacterial activity results showed that ethanolic extracts of C. hirta inhibited S. typhi and S. aureus at all concentrations, while aqueous extract inhibited bacterial growth in only 12.5% ??and 25% concentrations. These findings indicate that C. hirta has antibacterial activity that inhibits S. typhi and S. aureus. This information can be used for adding preliminary data to metabolite interest researchers, i.e., biologists and biotechnologists in the future.

Taking essential oil by water distillation and antibacterial activity test of refined water from agarwood plant parts (Aquilaria malaccensis Lamk)

Agarwood distilled water is a by-product produced during water distillation from wood containing resin in Aquilaria sp. Distilled water contains a small fraction of aromatic compounds obtained from plants during the distillation process which collects in distilled water. This research is expected to provide information about the potential of agarwood plant parts. The methods were raw material preparation, determination of water content, making distilled water, phytochemical screening and antibacterial activity test. The results were water content (average value 1.98-5.29 %) has met the BPOM RI standards, we met glycosides in leaf, trunk, skinned stems, bark. Parts of agarwood has antibacterial activity against Streptococcus mutants bacteria.