Standard Gravimetric Method Research Articles

Evaluation of Water Vapour Permeability of Some Food Grain Packaging Materials

The properties of any packaging material are essential parameters to know before storage of any kind of food materials. Physical properties are prerequisites for selecting proper packaging materials to obtain the desired shelf-life during the storage and distribution chain of food commodity. At the village/household level for packaging of food grains and other Non-Timber Forest Produce (NTFP) commodities, generally used packaging materials namely, low-density polyethylene (LDPE), polypropylene (PP), earthen pot (EP), polypropylene woven sack (PPWS), and gunny sack (GS) were evaluated for their physical properties such as strengths (grammage and thickness) and water vapour permeability using the standard gravimetric method. The thickness was determined to be 0.065 mm, 0.056 mm, 0.168 mm, 3.530 mm, and 0.849 mm for LDPE, PP, PPWS, EP, and GS respectively. Similarly, grammage was found to be 6.03 x 10-5 g m-2, 4.94 x 10-5 g m-2, 9.59 x 10-5 g m-2, and 3.70 x 10-4 g m-2 for LDPE, PP, PPWS, and GS respectively. Results revealed a significant difference between the permeability of packing materials. The highest water vapour permeability of 7.26 x 10-5 kg m-2 day-1 Pa-1 was obtained for GS, whereas the lowest 1.81 x 10-5 kg m-2 day-1 Pa-1 was for LDPE at 40 ± 1°C temperature and 90 ± 1% relative humidity. The water vapour permeability of other packaging materials viz., PP, PPWS, and EP was 2.18 x 10-5 kg m-2 day-1 Pa-1, 3.63 x 10-5 kg m-2 day-1 Pa-1, and 5.03 x 10-5 kg m-2 day-1 Pa-1 respectively.

Innovative Module Design for Advanced Automated Irrigation Systems

Aim:The paper aims to develop a soil moisture sensor utilizing copper material to enhance irrigation efficiency in regions like India. Calibration using the gravimetric method showcased the sensor's superior performance across various soil types. Integrated with an Arduino platform, an automated irrigation module was successfully tested. The developed system offers a practical solution for automated irrigation, even in water-scarce environments.
 Methodology: The study conducted in the Soil and Water Conservation Engineering Laboratory involved fabricating a soil moisture sensor with copper material. The experimental setup comprised four units: power supply, sensing, controller, and display. Calibration involved the standard gravimetric method to establish a linear equation correlating moisture sensor readings with soil moisture content.
 Results: Calibration revealed a linear relationship between the developed sensor's analog values and soil moisture content. Validation against the gravimetric method demonstrated high accuracy across the tested soil types and depths. Statistical analysis yielded low RMSE values (1.02, 1.013, and 1.022), high R² values, and a satisfactory NSE (0.90, 0.90, 0.89), confirming the sensor's reliability and precision.
 Conclusion: The developed soil moisture sensor, validated through rigorous testing, demonstrates superior performance across tested soil types. Integrated into an automated irrigation module, it offers an efficient solution for irrigation automation, contributing to water conservation and improved crop productivity.

КОРРЕЛЯЦИОННЫЙ АНАЛИЗ ЗАВИСИМОСТИ УСТАНОВЛЕННОГО КОЛИЧЕСТВА ТОНА В ОТРАЖЕННОЙ СПЕКТРАЛЬНОЙ (ЦВЕТОВОЙ) ГРУППЕ И КОРРОЗИОННОЙ СТОЙКОСТИ ОДНОФАЗНЫХ СПЛАВОВ СИСТЕМ NI-CR-MO: Х30Н60М9, HASTELLOY G-35 С ГЦК РЕШЕТКОЙ МАТРИЦЫ

This article discusses the results of a correlation analysis between the indicators (parameters) of the established amount of tone in the spectral group of reflected visible light and corrosion resistance for single-phase nickel alloys of the Ni-Cr-Mo: Kh30N60M9, Hastelloy G-35 systems with a solid solution structure. The initial data for the analysis were the data obtained as a result of the analysis of the tone components of the reflected visible light by calculating the wavelength of the reflected light. The developed software estimated the amount of tone in the participating color groups, reflected visible light, where the tone is estimated by wavelength, determining the participating color groups. Further, the amount of tone determined in the color group is recalculated by the number of image elements - pixels, already offering the tone density in the color group. Corrosion rates were determined by a standard gravimetric method according to ASTM G-28 "A". Correspondence of the parameters: tone and corrosion rates for the alloys under consideration after various heat treatments indicated their high negative connection. The established fact allows us to state that a larger tone value determined for the pixel fragment characterizes a lower corrosion rate and better corrosion resistance in identical test conditions. The indicator correlation coefficient is determined at the level of - 0.93

Performance Evaluation of the Water Advisory for Irrigation Scheduling System (WAISS) Capacitance Soil Moisture Sensor

The agriculture sector accounts for 80% of the total freshwater resource use in the Philippines. With increasing competition for the scarce water supply, it is necessary to utilize water resources efficiently. The application of smart irrigation technology can help achieve higher water use efficiency, increase farm water productivity, and maximize crop yield. To minimize excess or insufficient irrigation water application to crops, and provide more effective and efficient water management, an integrated water monitoring system called Water Advisory for Irrigation Scheduling System (WAISS) was developed. The performance of WAISS was initially evaluated by comparing the soil moisture measurements of its capacitance soil moisture sensor with a commercially developed sensor and the standard gravimetric method. Statistical analysis shows that the low-cost WAISS soil moisture sensors are comparable with the commercially developed sensors with a Percent Error of 5.5% compared to METER ECH2O EC-5's 16.1%. This highlights WAISS' potential as a cost-effective yet reliable alternative for soil moisture monitoring.

SORPTION AND THERMODYNAMIC PROPERTIES OF AROMATIC PLANTS AS DRYING OBJECTS

The high demand for aromatic herbs in the biotechnological, cosmetic, pharmaceutical and food industries led to increased requirements for the technological processes of processing aromatic raw materials to preserve biologically active substances and essential oils. Peppermint (Mentha piperita L.) is a well-known medicinal essential oil crop that is widely distributed throughout Ukraine. It is widely used due to its beneficial properties and therapeutic effect on the human body.
 The purpose of the article is studies of sorption and thermodynamic properties of aromatic plants to determine technological parameters of drying and storage processes, which ensure minimum specific energy consumption and maximum preservation of essential oils.
 The results of study on sorption properties of peppermint leaves are presented. Adsorption moisture isotherms of peppermint leaves were determined at three different temperatures 30, 40 and 50 ºC, using the standard gravimetric static method. The net isosteric heat of adsorption was calculated from moisture isotherms, using the Clausius-Clapeyron equation.
 The specific heat consumption for drying peppermint leaves at temperatures of 40 and 50 ºС was obtained experimentally, using the differential microcalorimeter of evaporation. The effect of volatile substances of peppermint essential oil on the heat of vaporization was revealed.
 The choice of drying temperature of aromatic plants is primarily determined by the thermal sensitivity of essential oils. The study of the effect of drying temperature on the removal of volatile aromatic compounds from peppermint leaves showed that the maximum allowable temperature of the material during dehydration should not exceed the melting point of menthol at 42,5 ºС.

Measurement of moisture contents in concrete blocks using fringing field spiral capacitive sensors

This work reports the design and development of a fringing field, planar capacitive sensor with spiral configuration for measuring moisture contents in concrete blocks, following printed circuit board technology. This method is non-destructive, non-intrusive, cost effective, and provides rapid results. The performances of the fabricated sensors are evaluated with experiments on three different types of concrete blocks. The measured capacitance values are plotted against moisture contents in concrete blocks, measured following the standard gravimetric method. As moisture contents in concrete blocks increase from 0% to 11.34%, the corresponding interelectrode capacitance, which is a measure of the moisture contents, is found to increase by nearly 74%, providing high moisture content sensitivity for the method. The results of the measurements are presented and the implications of the results discussed in the paper. A comparison of the relevant technical parameters of the present system with those of existing technologies are also presented and discussed.

Assessment of the adverse effect of crop residue burning on respiratory health: a case study of Patiala, India

BackgroundCrop residue burning (CRB) is one of the top contributors to ambient air pollution (particulate matter 2·5 [PM2·5]) in north-western India. Despite the magnitude of the problems associated with high particulate amounts, there are few epidemiological data in India on the associated health effects of CRB, focusing on rural populations. The present study was conducted to quantify the effect of PM2·5 from CRB on the respiratory health of agricultural community in the Nabha block in Patiala, India. MethodsParticipants aged 10–60 years who were residents of six villages in the Nabha block in Patiala, India, who had resided in the area for at least 10 years and had self-reported as being in good health and non-pregnant women were enrolled in this cross-sectional study using purposive sampling. The participants were recruited from their residence, and all volunteered to participate in the study. The study population was surveyed for self-reported health symptoms and other exposure confounders. Lung function tests (LFTs) were done to examine forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and peak expiratory flow (PEF), both during CRB and non-CRB periods. 24-h continuous PM2·5 monitoring was done using the modified low-volume Combo Dust Samplers and particles were collected in glass fiber filters. The PM2·5 mass concentrations were analysed using the standard gravimetric method. Multiple regression models were used to quantify the association of PM2·5 from CRB on respiratory health after controlling for other exposure variables; namely, cooking fuel, ventilation, and distance from the road. FindingsA total of 3644 participants were enrolled from Oct 16 to 26, 2018, and March 7 to April 3, 2019 (the non-CRB periods), and from Oct 27 to Nov 20, 2018 and from Nov 3 to 13, 2019 (CRB periods). The present study showed significant associations between PM2·5 exposure and poor respiratory health with an increased prevalence of respiratory symptoms and lung function decrement among the study population. The older group (>40–60 years) reported more respiratory complaints during CRB than the younger groups (10–18 and >18–40 years), including coughs (OR 1·57; 95% CI 1·14–2·16), phlegm (1·69; 1·19–2·16), and itchiness of the eyes (3·44; 2·54–4·66). The study found a decrease in the results of LFTs with increasing PM2·5 across all age groups during CRB compared with the non-CRB period. The youngest group (10–18 years) had the highest reduction in lung capacity based on LFT variables. In men, FEV1 declined 16% in those aged 10–18 years, 9% in those aged older than 18 to 40 years, and 10% in those older than 40 to 60 years; and in women, it declined 26% in those aged 10–18 years, 12% in those older than 18 to 40 years, and 7% in those older than 40 to 60 years, during CRB (with a mean PM2·5 increase of 167 μg/m3). Similar declines were noted for the other (FVC and PEF) lung function variables. InterpretationThis study, which shows the adverse effects on health from CRB (increases in respiratory symptoms and poor lung function), highlights to need to accelerate policy interventions and engage farmers in discussions on CRB elimination. FundingCentral Pollution Control Board of India (B-33014/40/2018/AQM-EPC 9836).

Development of semi-automatic recalibration system and curve-fit models for smart soil moisture sensor

Reliable measurement of soil moisture is one of the primary requirements for agriculture, irrigation management, and the study of soil–water dynamics. To improve the accuracy of a smart soil moisture sensor beyond the manufacturer's calibration, there is a need for soil-specific recalibration and improved sensor models. This paper discusses the development of a semi-automatic virtual instrumentation system integrated with a standard gravimetric method for soil-specific recalibration of a relatively new, low-cost capacitive soil moisture sensor, SoilWatch 10, in loamy–sandy soil. Using dual sensor with confidence-weighted averaging sensor fusion method, variance in the raw sensor readings is minimized. Further, the pre-processed recalibration data is used to develop linear, polynomial, and optimized 3-layer FFBP-NN (feedforward backpropagation neural network) direct and inverse models of the sensor. Performance evaluation of the models indicate that goodness of fit and accuracy of the FBNN models is the highest, followed by the polynomial and linear models.

On the quantitative assessment of corrosion damages of aluminum at the early stages using confocal laser scanning microscopy

Despite being widely used in such industries as chemical, aviation and food ones, aluminum and its alloys are known to be prone to localized corrosion, and this remains a problem to be solved, especially when it comes to pitting corrosion. Therefore, there is a necessity to detect traces of corrosion at the earliest stages and to quantify the extent of corrosion damage. The simplest solution for assessing the overall corrosion rate is to use the gravimetric method, which, however, does not provide information for assessment of localized corrosion. This paper is devoted to the consideration of the possibilities of using the method of confocal laser scanning microscopy (CLSM) for assessing corrosion resistance using high-purity aluminum. The CLSM method, due to its high resolution (especially along the vertical axis), enables to obtain quantitative data on the volume of corroded metal, determine the depth of corrosion damage including building their profilograms, and analyze the morphology of the surface damaged by corrosion. Owing to the high sensitivity of the CLSM method, corrosion losses were detected within 21 days, contrary to the standard gravimetric method, which failed to determine the loss of metal even after 160 days of corrosion testing.

Microfluidic Thermal Flowmeters for Drug Injection Monitoring

This paper presents a microfluidic thermal flowmeter for monitoring injection pumps, which is essential to ensure proper patient treatment and reduce medication errors that can lead to severe injury or death. The standard gravimetric method for flow-rate monitoring requires a great deal of preparation and laboratory equipment and is impractical in clinics. Therefore, an alternative to the standard method suitable for remote, small-scale, and frequent infusion-pump monitoring is in great demand. Here, we propose a miniaturized thermal flowmeter consisting of a silicon substrate, a platinum heater layer on a silicon dioxide thin-membrane, and a polymer microchannel to provide accurate flow-rate measurement. The present thermal flowmeter is fabricated by the micromachining and micromolding process and exhibits sensitivity, linearity, and uncertainty of 0.722 mW/(g/h), 98.7%, and (2.36 ± 0.80)%, respectively, in the flow-rate range of 0.5–2.5 g/h when the flowmeter is operated in the constant temperature mode with the channel width of 0.5 mm. The measurement range of flow rate can be easily adjusted by changing the cross-sectional microchannel dimension. The present miniaturized thermal flowmeter shows a high potential for infusion-pump calibration in clinical settings.

Performance Assessment and Calibration of Low-cost Moisture Sensors at Multiple Oxisol Depths

Monitoring of soil moisture is a key component in irrigation management and can be carried out with the aid of low-cost electromagnetic sensors. This study aimed to develop calibration equations for the HFM2030 sensor at different depths (0-20; 20-40; 40-60; 60-80; 100 cm) of Oxisols and to assess the accuracy levels of calibration equations used in the continuous monitoring of soil moisture. Reference values of soil moisture content were measured by a standard gravimetric method, converted to volumetric moisture, and then compared with sensor readings to develop calibration equations. The fit of the regression function was evaluated based on the determination coefficient (R2). The results indicated that the calibration equations were linear at different soil depths. Calibrating the HFM2030 sensor improved the estimate of volumetric water content by 31.21%, 23.46%, 24.93%, 31.93%, and 41.18% in the 0-20, 20-40, 40-60, 60-80 and 80-100 cm layers, respectively. Here, it is demonstrated that the correct calibration of HFM2030 should precede the installation and use of these sensors in the field. The results of this study represent another step toward the development of criteria aiming for greater precision in the use of sensors in irrigation management. The calibration equations developed in this study can be applicable and useful for farmers and researchers working with HFM2030 sensors in similar soil conditions in other regions of Brazil and globally.

Gravimetric and instrumental methods comparison for experimental determination of carbonate carbon content in solid mineral fuels

The content of combustible elements in solid mineral fuels (carbon, hydrogen, etc.) are very important, since they most directly affect the heat value. It should be noted that the fuel heat value depends on many other constituents, such as ash and moisture. In this paper, special attention has been paid to carbon content. In solid mineral fuels, carbon is found alone or bound in the form of various compounds. One of them is mineral carbonate compounds bound as carbonate carbon, which originates from absorbed CO2 from atmosphere. Determination of carbonate carbon content of solid mineral fuels was performed by standard gravimetric method (according to ISO 925: 2019), and newly developed instrumental method, using thermogravimetric analyzer LECO TGA 701. Comparison of obtained experimental results was done. Four types of coal, Kolubara lignite, Kostolac lignite, brown coal, and control coal sample were included in experimental analysis. In addition, moisture in the samples was also determined using analytical method and inspected using LECO TGA 701 thermogravimetric analyzer, as well as total carbon content using the LECO CHN 628 elemental analyzer. An analysis and comparison of the obtained results was performed, and comments and conclusions are presented. The experiments were done in the department for fuel characterization, Laboratory for Thermal Engineering and Energy, Institute of Nuclear Sciences Vinca.

Groundwater quality of an hard rock aquifer in the Subledu Basin of Khammam district, India

Hard rock aquifers of Indian peninsula are loaded with excess nitrate due to heavy use of fertilizers during irrigation and excess fluoride due to the geogenic contamination. This study is focused on the groundwater quality in Subledu Basin in view of the large-scale use of groundwater for both irrigation and drinking purposes as no such study was carried out earlier in the basin. The study area is located at Khammam district, Telangana state, India, which is a hard rock terrain mostly covered with granites and gneisses. Twenty-two groundwater samples were collected covering the entire basin in the month of May 2019 from running hand pumps for analyzing the major anions and cations in the groundwater. The samples were analyzed by using standard gravimetric method for evaluation of total dissolved solids; titrimetric methods to analyze carbonates, bicarbonates and chloride; UV spectrometric method for estimation of nitrate; and ion-selective electrode method for fluoride and spectrophotometer for sulfate and phosphate. These chemical constituents are used to calculate parameters, namely total hardness, sodium adsorption ratio, residual sodium carbonate, sodium percentage, Kelley’s ratio and magnesium hazard. The spatial distribution maps of important chemical constituents are prepared by using the contour maps created by utilizing the inverse distance weighted interpolation tool in the Geographical Information System. The excess fluoride values of 2.84 mg/l, 2.76 mg/l and 1.87 mg/l are observed in the villages of Pocharam, Kistapuram and Turakagudem, respectively, as against the maximum permissible concentration of 1.5 mg/l prescribed by World Health Organization. Excess use of fertilizers for agriculture is causing the nitrate pollution of groundwater in more than 50% of the samples with concentrations ranging from a minimum of 2 mg/l to a maximum of 460 mg/l in the villages of Medidapalle and Bachodu. It is identified that the total hardness is ranging between 200 and 820 mg/l which is very high when compared with the Bureau of Indian Standards. Based on sodium adsorption ratio, residual sodium carbonate, Kelley’s ratio, and sodium percentage analyses, two samples were not suitable for irrigation. Similarly, 13 samples are not suitable for drinking water purposes based on the excess presence of fluoride and nitrate. Groundwater quality maps of Subledu Basin depicting the areas suitable or not for the irrigation as well as for drinking purposes were prepared. From these maps, it is found that groundwater from large parts of the basin is not suitable for drinking purposes while for irrigation purposes it is suitable.

A real-time light-scattering technique for tailings solids measurement.

This study presents the concept of an economic in situ light-scattering sensor for real-time measurement of the solid content in tailings facilities. An experimental setup using a blue (405nm wavelength) laser diode and silicon photodiodes was constructed to measure the angular distribution of the intensity of scattered light. It was found that the angular intensity of scattered light for tailing samples follows a cosn (θ) relation with n≈1.5, where θ is the angle between the laser beam and the photodiode. An angular value of θ =20° was chosen for the sensor design based on a high signal-to-noise ratio. The setup was used to determine the relation between scattered light intensity and solids content using a thickened tailings underflow from an oil sands facility and Kaolin as a model material. It was observed that the intensity of scattered light tends to increase with an increase in solids content, with qualitatively similar settling behavior for the two materials but at largely different time scales. An insertion-based prototype was built and tested in a large (2.7m height) settling column with treated mature fine tailings, and the light-scattering data were verified by standard gravimetric method and gamma-ray measurements. In general, good agreement was established between these measurements in the absence of optical fouling, which demonstrates the potential of the sensor as an effective tool for tailings management.

Study of Pumpkin Drying Through Magnetic Resonance Imaging

Nuclear Magnetic Resonance (NMR) and Magnetic Resonance Imaging (MRI) techniques are widely used in food science, mainly because they are non-invasive techniques. MRI, as a non-destructive technique, allows the study of intact samples and without any preparation of the samples before analysis. In food processing, the monitoring of distribution and water content is a consolidated analysis technique, frequently used on the market in order to preserve appropriate nutritional and health characteristics of food according to quality standards. In a food matrix, the variation of the water content is related to the changes in the internal structure and in the physico-chemical properties that occur during the transformation process. In this study MRI technique is used to evaluate the variation of the water content as a function of the drying time. Pumpkin samples are analyzed at four different drying temperatures of 50, 60, 65, and 70°C. The transverse relaxation time, T2, is used to assess the hydration level of the samples by comparing the information extracted from MR images with the drying kinetics measured by gravimetric method. Moreover, T2 maps are used to correlate the change in water distribution with the change in T2 values. The results show that the global weight loss curves obtained with the standard gravimetric method and with the MRI data are in excellent agreement. This work indicates that monitoring changes in the T2 profile of food (i.e., pumpkin) is a useful method for evaluating moisture profiles and changes induced on the sample during the drying process.

Recalibration and performance comparison of soil moisture sensors using regression and neural network characteristic models

In this work, laboratory based virtual instrumentation (VI) system for recalibration of various smart soil moisture sensors is implemented along with modelling and performance analysis of these sensors. This semiautomatic VI system integrates the standard gravimetric method with wireless data acquisition device to ascertain gravimetric water content in the field soil and online acquisition and analysis of the corresponding voltage samples of the sensors. The proposed VI system, is effectively used to test and record the recalibration data of commercially available analogue groove resistive sensor and capacitive (V1.0) soil moisture sensors and devise efficient characteristics models for the same. Both least-square linear-fit and polynomial-fit inverse models reveal that non-linear model of capacitive soil-moisture sensor has high accuracy (R2 = 0.98) as compared to resistive soil moisture sensor (R2 = 0.96). Further, to enhance measurement accuracy of capacitive soil moisture sensor, 3-layer neural network is modelled using back propagation algorithm to describe the output-input relationship of capacitive senor providing highest value of accuracy (R2 = 0.99). Easy to use and operate with remote connectivity, the VI tool offers ready to use on-site system for recalibration, modelling and comparison of many smart soil moisture sensors for reliable use in IoT based irrigation and water management.

Study on the Effects of Physical Properties of Tenera Palm Kernel during Drying and Its Moisture Sorption Isotherms

A study on the effect of the physical properties and moisture sorption isotherm of palm kernels constitutes the critical criteria in evaluating the drying performance. The drying was evaluated as a function of moisture content (MC) in the range of 0.31–0.02 kg/kg (d.b.). Whereas, the equilibrium moisture content (EMC) of palm kernels (whole kernel and ground kernel) was determined experimentally using the standard gravimetric method at different temperatures (50 °C to 80 °C), over a range of relative humidity (RH) from 10% to 81%. Palm kernel length, width, and thickness decrease from 16.08 ± 2.09 mm to 14.17 ± 2.30 mm, 12.06 ± 1.40 mm to 11.24 ± 1.08 mm, and 10.01 ± 1.27 mm to 9.18 ± 1.04 mm, respectively, when MC decreased. Bulk density, surface area, and specific surface area decreased as the MC decreased, while porosity and true density were increased. EMC of palm kernels (whole kernel and ground kernel) decreased with an increase in temperature at constant RH. Modified Oswin and modified Halsey models were found to be the best for predicting desorption moisture isotherms for whole and ground palm kernel, respectively. Therefore, the study of the effect of drying on physical aspects as well as moisture sorption isotherms is important to further analyze the drying performance of Tenera palm kernel (e.g., equipment design and energy requirement).

Sorption behavior and storage stability of microencapsulated transglutaminase by ultrasonic spray–freeze–drying

Adsorption isotherms at 25 °C and 38 °C for microencapsulated microbial transglutaminase (mTG) powder produced by ultrasonic spray–freeze–drying (USFD), conventional spray drying (CSD), and conventional freeze–drying (CFD) methods and USFD–crude (without coating materials) were obtained using the standard static gravimetric method, and experimental data were fitted to the mathematical models. The sorption isotherms exhibited type III behavior, and the Ferro–Fontán model was selected as the best fit, having an R 2 of 0.920–0.995. The sorption isotherms of mTG powder depended on temperature and drying methods. The equilibrium moisture content decreased with increasing temperature, and the monolayer moisture content of the USFD sample was lower than other microencapsulated samples (M 0 = 0.133 kg/kg dry solids for 25 °C and M 0 = 0.080 kg/kg dry solids for 38 °C from Guggenheim–Anderson–deBoer model), followed by CFD and CSD. Furthermore, the storage stability of mTG powders produced by different methods in terms of quality parameters including enzyme activity, moisture content, water activity, color, density, porosity, flowability, and caking degree value was studied in aluminum-laminated polyethylene (ALPE) pouches under storage conditions of 25 °C, 50% relative humidity (RH) for 180 days and 38 °C, 90% RH for 90 days. Inactivation kinetics, the effect of drying methods, and application of the microencapsulation process were also examined on mTG powder during the storage period. The first-order kinetic reaction was successfully applied to the relative activity values of all samples for both storage conditions. Both the drying method and application of microencapsulation showed a significant effect on enzyme activity. When comparing the drying techniques, the USFD samples were the most stable, having 816 and 465 days of half-life times for both storage conditions, respectively. Storage at 25 °C, 50% RH increased the half-life twofold compared with that of the USFD samples kept at 38 °C, 90% RH. The physical properties of mTG powder obtained either USFD, USFD–crude, CFD, or CSD showed that moisture content and wettability values increased, while caking degree and enzyme activity values decreased during storage. USFD samples had the lowest moisture content (5.48%) and Hausner ratio (1.12) and the highest relative activity (86.2%) compared with other samples after 180 days storage at 25 °C, 50% RH. When all quality characteristics and enzyme stability were considered, the USFD method was superior to others, and it was determined to be the best method for the production of microencapsulated mTG powders. mTG powders stored at 25 °C, 50% RH exhibited a longer shelf life.

Accuracies of Soil Moisture Estimations Using a Semi-Empirical Model over Bare Soil Agricultural Croplands from Sentinel-1 SAR Data

This study describes a semi-empirical model developed to estimate volumetric soil moisture ( ϑ v ) in bare soils during the dry season (March–May) using C-band (5.42 GHz) synthetic aperture radar (SAR) imagery acquired from the Sentinel-1 European satellite platform at a 20 m spatial resolution. The semi-empirical model was developed using backscatter coefficient ( σ ° dB ) and in situ soil moisture collected from Siruguppa taluk (sub-district) in the Karnataka state of India. The backscatter coefficients σ V V 0 and σ V H 0 were extracted from SAR images at 62 geo-referenced locations where ground sampling and volumetric soil moisture were measured at a 10 cm (0–10 cm) depth using a soil core sampler and a standard gravimetric method during the dry months (March–May) of 2017 and 2018. A linear equation was proposed by combining σ V V 0 and σ V H 0 to estimate soil moisture. Both localized and generalized linear models were derived. Thirty-nine localized linear models were obtained using the 13 Sentinel-1 images used in this study, considering each polarimetric channel Co-Polarization (VV) and Cross-Polarization (VH) separately, and also their linear combination of VV + VH. Furthermore, nine generalized linear models were derived using all the Sentinel-1 images acquired in 2017 and 2018; three generalized models were derived by combining the two years (2017 and 2018) for each polarimetric channel; and three more models were derived for the linear combination of σ V V 0 and σ V H 0 . The above set of equations were validated and the Root Mean Square Error (RMSE) was 0.030 and 0.030 for 2017 and 2018, respectively, and 0.02 for the combined years of 2017 and 2018. Both localized and generalized models were compared with in situ data. Both kind of models revealed that the linear combination of σ V V 0 + σ V H 0 showed a significantly higher R2 than the individual polarimetric channels.

Real-time Monitoring of Suspended Particulate Matter in Indoor Air: Validation and Application of a Light-scattering Sensor

ABSTRACT Since the 1950s, awareness of the impact of air pollution on human health has been growing. Of the many recognized air pollutants, suspended particulate matter has received the most attention, as both PM2.5 and PM10 can affect humans upon inhalation. Consequently, PM monitoring is critical to linking indoor pollution and exposure, and a validated measuring instrument is essential. Portable monitors, which track temporal changes in the aerosol mass concentration in real time, are a faster alternative to offline gravimetric techniques, which provide only averaged values. Hence, this study evaluated the performance of the DustTrak DRX aerosol monitor in assessing indoor air quality and validated its ability to measure complex aerosols. Three DustTrak units were used to measure different aerosols, e.g., ambient air, polystyrene latex (PSL) spheres, and environmental tobacco smoke (ETS), and the results were compared to those obtained with the standard gravimetric method. Notably, the bias of the DustTrak relative to the gravimetric method for ETS measurements ranged from 2% to 15% when a photometric calibration factor (PCF) of 0.38 was applied. Additionally, the working range of the tested units was established, and the limits of detection and quantification were found to be 5 and 15 µg m–3, respectively. Finally, in order to serve as an alternative to the gravimetric method, these instruments must be accredited for PM measurement in accordance with standards such as ISO 17025.