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The filter paper (FP) method, a cost-effective, versatile, and convenient approach, has found extensive application in analyzing fine-grained soils, enabling the successful measurement of a broad spectrum of total and matric suctions. However, using the FP method in sand with a limited range of suction profiles has been notably underrepresented in the existing literature. Therefore, this study investigated the applicability of the contact FP method in establishing soil water retention curves (SWRCs) using five distinct FP calibration curves for 10 poorly graded sands. Among these calibration curves, the one presented by Chandler yielded the highest suction values, which were followed by those of ASTM. Furthermore, the FP results were subjected to fitting with a mathmatical model, which led to the observation that the overall trends in the obtained SWRCs displayed smooth sigmoidal shapes, resulting in a complete and coherent SWRCs. The SWRC results of five sand samples were assessed through validation against the hanging column technique (HCT) results, indicating a high degree of concordance and affirming the suitability of the FP method for sands characterized by a limited suction profile. Notably, the entire range of suction values fell within the 0.01–20 kPa range based on the calibration curves presented by Chandler and ASTM for all the examined sand samples, except sands 9 and 10. Furthermore, the suction values were unobtainable using the two aforementioned calibration curves within the ranges of 0.01–1.47 kPa and 0.01–0.172 kPa. [ABSTRACT FROM AUTHOR]

Background: Commissioning of treatment planning systems (TPS) and beam delivery for scanned light ion beams is an important quality assurance task. This requires measurement of large sets of high quality dosimetric data in anthropomorphic phantoms to benchmark the TPS and dose delivery under realistic conditions., Method: A novel measurement setup is described, which allows for an efficient collection of a large set of accurate dose data in complex phantom geometries. This setup allows dose measurements based on a set of 24 small volume ionization chambers calibrated in dose to water and mounted in a holder, which can be freely positioned in a water phantom with various phantoms mounted in front of the water tank. The phantoms can be scanned in a CT and a CT-based treatment planning can be performed for a direct benchmark of the dose calculation algorithm in various situations., Results: The system has been used for acceptance testing in scanned light ion beam therapy at Heidelberg Ion Beam Therapy Center for scanned proton and carbon ion beams. It demonstrated to be useful to collect large amounts of high quality data for comparison with the TPS calculation using various phantom geometries., Conclusion: The setup is an efficient tool for commissioning and verification of treatment planning systems. It is especially suited for dynamic beam delivery, as many data points can be obtained during a single plan delivery, but can be adapted also for other dynamic therapies, like rotational IMRT.

This paper proposes a 6Gbps receiver for 8K 240Hz OLED display. In the proposed receiver, video image compression is presented to double the effective data bandwidth. In addition, it proposes dual path CTLE offset voltage calibration and CTLE adaptation with eye margin tester to implement 6Gbps receiver. The prototype IC is implemented in a 0.18μm HVCMOS process and is evaluated as an 8K 65‐inch panel. [ABSTRACT FROM AUTHOR]

The use of reference solutions dispersed on filter paper discs is proposed for the first time as an external calibration strategy for matrix matching and determination of As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sr, V and Zn in plants by laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS). The procedure is based on the use of filter paper discs as support for aqueous reference solutions, which are further evaporated, resulting in solid standards with concentrations up to 250 μg g −1 of each element. The use of filter paper for calibration is proposed as matrix matched standards due to the similarities of this material with botanical samples, regarding to carbon concentration and its distribution through both matrices. These characteristics allowed the use of 13 C as internal standard (IS) during the analysis by LA-ICP-MS. In this way, parameters as analyte signal normalization with 13 C, carrier gas flow rate, laser energy, spot size, and calibration range were monitored. The calibration procedure using solution deposition on filter paper discs resulted in precision improvement when 13 C was used as IS. The method precision was calculated by the analysis of a certified reference material (CRM) of botanical matrix, considering the RSD obtained for 5 line scans and was lower than 20%. Accuracy of LA-ICP-MS determinations were evaluated by analysis of four CRM pellets of botanical composition, as well as by comparison with results obtained by ICP-MS using solution nebulization after microwave assisted digestion. Plant samples of unknown elemental composition were analyzed by the proposed LA method and good agreement were obtained with results of solution analysis. Limits of detection (LOD) established for LA-ICP-MS were obtained by the ablation of 10 lines on the filter paper disc containing 40 μL of 5% HNO 3 (v v −1 ) as calibration blank. Values ranged from 0.05 to 0.81 μg g −1 . Overall, the use of filter paper as support for dried aqueous standards showed to be a useful strategy for calibration and plant analysis by LA-ICP-MS. [ABSTRACT FROM AUTHOR]

Laser induced breakdown spectroscopy is explored for the estimation of Zr in metallic fuel and pyrochemical reprocessing stream using filter paper as a sample substrate. Zr(II) emission line at 339.20 nm has been identified and used for its quantitative determination. Calibration curves are obtained after normalizing the intensity of Zr to C/Y emission lines as an internal standard, to get better linearity. Analytical capability of LIBS for Zr estimation is tested by comparing the measured value with ICP-OES in simulated samples. Good agreement between the measured values confirms the ability of LIBS application in nuclear streams. [ABSTRACT FROM AUTHOR]

Recycled paper is extensively used worldwide. In the last decades, its market has expanded considerably. The increasing use of recycled paper in papermaking has led to the production of paper containing several types of impurities. Consequently, wastepaper mills are forced to implement quality control schemes for evaluating the incoming wastepaper stock, thus guarantying the specifications of the final product. The main objective of this work is to present a fast and reliable system for identifying different paper types. Therefore, undesirable paper types can be refused, improving the performance of the paper machine and the final quality of the paper manufactured. For this purpose, two fast techniques, i.e., Fourier transform midinfrared (FTIR) and reflectance near infrared (NIR), were applied to acquire the infrared spectra of the paper samples. Next, four processing multivariate methods, i.e., principal component analysis, canonical variate analysis (CVA), extended CVA (ECVA), and support vector machines (SVMs), were employed in the feature-extraction or dimension-reduction stage. Afterward, the k nearest neighbor (kNN) algorithm was used in the classification phase. Experimental results show the usefulness of the proposed methodology and the potential of both FTIR and NIR spectroscopic methods. Using the FTIR spectrum in association with SVM and kNN, the system achieved a maximum classification accuracy of 100%, whereas using the NIR spectrum in association with ECVA or SVM and kNN, the system achieved a maximum classification accuracy of 96.4%. [ABSTRACT FROM PUBLISHER]

We evaluate the geometric distortion on video see‐through (VST) head‐mounted displays (HMDs) with single‐camera and dualcamera design. We present the experimental setup and metrology for geometric calibration and VST geometric distortion measurement. Physical geometric distortion is compared to the distortion of digital content on a VST HMD. We investigate the impacts of camera misalignment and depth distance on VST geometric distortion with angular‐based distortion correction. [ABSTRACT FROM AUTHOR]

A submersible UV/VIS spectrometer was used to monitor a paper mill wastewater treatment plant. It utilises the UV/VIS range (200-750 nm) for simultaneous measurement of COD, filtered COD, TSS and nitrate with just a single instrument. The instrument measures in-situ, directly in the process. Paper mill wastewater shows typical and reproducible spectra at various process measuring points. There is a relative maximum at 280 mm due to the absorbance by dissolved organic substances, mainly ligninic acids. Comparison of absorbance spectra distinctly shows the decrease of this peak, indicating biological degradation throughout the treatment process. Summarising, one can say that paper mill wastewater cannot be monitored by a simple UV probe measuring only the absorbance at a single wavelength. The required information can only be gained from the whole spectra. Regarding plant control it is suggested that only the overall spectral information is used. Calibrations to conventional parameters are now merely carried out for purposes of reference-checking. [ABSTRACT FROM AUTHOR]

Application of integrated hydrological models to manage a watershed’s water resources are increasingly finding their way into the decision-making processes. The Soil and Water Assessment Tool (SWAT) is a multi-process model integrating hydrology, ecology, agriculture, and water quality. SWAT is a continuation of nearly 40 years of modeling efforts conducted by the United States Department of Agriculture (USDA) Agricultural Research Service (ARS). A large number of SWAT-related papers have appeared in ISI journals, building a world-wide consensus around the model’s stability and usefulness. The current issue is a collection of the latest research using SWAT as the modeling tool. Most models must undergo calibration/validation and uncertainty analysis. Unfortunately, these sciences are not formal subjects of teaching in most universities and the students are often left to their own resources to calibrate their model. In this paper, we focus on calibration and uncertainty analysis highlighting some serious issues in the calibration of distributed models. A protocol for calibration is also highlighted to guide the users to obtain better modeling results. Finally, a summary of the papers published in this special issue is provided in the Appendix.

This article describes a new approach for performing analytical assays on paper-based analytical devices that relies on the principles of multiple standard additions calibration, and uses calibrant-loaded paper devices. Calibrant-loaded devices have multiple sensing areas pre-loaded with an excess amount of the necessary colorimetric reagents and known amounts (standard solutions) of the tested analyte; thus, a colored product is developed before analysis in each sensing area. After sample addition, the analytical signal from each sensing area corresponds to the total concentration of the analyte, which is the sum of the concentration of the analyte in the tested sample plus the known amount of the analyte pre-stored in the device. The combined signal retrieved from each sensing zone is plotted to form a standard addition calibration curve that is used to calculate the concentration of the analyte in the sample using linear or non-linear models (i.e., first or higher order polynomials). This new approach could reduce the influence of matrix effects, paper inhomogeneity and environmental conditions on the results, and it could simplify the analysis as it may eliminate the steps associated with on-spot calibration that should ideally be performed using standard solutions that are prepared or transported in-situ. The utility and applicability of this approach is demonstrated as proof-of-concept on five assays (i.e., for the determination of iron, protein, hydrogen peroxide, acetic acid and carbonate ions) that use different reactions (i.e. complexation, oxidation and neutralization). This work provides a demonstration of a multiple standard addition methodology applied on calibrant-loaded paper-based analytical devices and illustrate its use as a sample-in result-out tool for point-of-use applications. [ABSTRACT FROM AUTHOR]

Filter paper technique (FPT) is known to measure both matric and total suctions in a wide measurement range. However, it has many individual errors due to the uncertainty of calibration curve and sensitivity of the measurements to the temperature and relative humidity variations. Besides, the ASTM procedure for FPT does not specify any sample preparation and repetition for experiments. In this regard, this study covers the reliability of suction measurements using the FPT and its application on zeolite-bentonite mixtures (ZBMs), which were proposed for use of liner material in the literature. A calibration curve for Whatman No. 42 filter paper was constructed and compared to the other calibration curves given in the literature. Due to large scatter of calibration curves, total suction measurement is found to be inconvenient for suction values under 1000 kPa. An improvement in sample preparation and necessary minimum numbers of tests are also suggested. When preparing the test specimen, the compacted sample is recommended not to be cut but to be compacted separately as upper and lower parts where the contact filter paper to be placed in between in order to obtain good contact area to measure the matric suction accurately. The necessary minimum numbers of tests for ± 10% accuracy band in a confidence level of 95% for ASTM procedure on ZBMs are suggested. Repetitions were found to vary depending on the suction type and bentonite content. Repetitions of six and eight times are recommended for 10% ZBMs for matric and total suction measurements, respectively. Similarly, for 20% ZBMs the repetitions of six and ten times are found for matric and total suction measurements, respectively. In addition, the influence of index properties and compaction states on suction was also investigated. Matric suction values decrease from dry of optimum water content to the wet of optimum water content and approach to zero for higher water contents. The suction values are found to increase with decreasing water contents where the dry density and the void ratio were constant. On the other hand, for a given water content, matric suction values are found to be increasing with increasing dry densities, while the void ratio was decreasing being more evident at relatively higher saturation degrees. [ABSTRACT FROM AUTHOR]

This article describes a new, simplified approach for performing quantitative colorimetric assays on paper-based analytical devices that uses calibrant-loaded paper devices to perform external calibration and standard addition calibration using one calibration point. Calibrant-loaded devices consist of sensing areas pre-loaded with a colored product which is produced from the reaction of a standard solution of the analyte with the appropriate colorimetric reagents. When the sample is added into the calibrant-loaded sensing zone the analytical signal (i.e. color intensity) increases proportionally to the concentration of the analyte in the tested sample. The total measured signal corresponds to the sum of the concentration of the analyte in the sample and the standard solution pre-stored in the device and is used to calculate the concentration of the analyte in the sample based on the principles of linear calibration. The applicability of this approach was benchmarked in three colorimetric assays (i.e., for the determination of iron, nickel, and amino acids) that use different reaction chemistries. This work demonstrates a simplified calibration-free approach for assays performed on paper-based analytical devices that requires minimum experimental and computational effort, it can be used for either external or standard addition calibration and can be used to identify and eliminate the presence of interferences in a sample. Image 1 • A new and simplified approach for quantitative assays on paper devices is described. • Single-point calibration and standard addition on paper devices is demonstrated. • The method can be used to identify the presence of interferences in the sample. • The method produces rapid results with minimum user effort and technical resources. [ABSTRACT FROM AUTHOR]

The Z-directional strength of paper fiber bonds is an important parameter for the paper and board industry. The current methods of studying Z-directional paper fiber bond strength rely on handsheet measurements. This paper presents a novel tool for measuring the Z-directional strength of individual paper fiber bonds. A polyvinylidenefluoride (PVDF) film microforce sensor, with a special specimen holder, was designed, fabricated and calibrated to perform the measurements. The microforce sensor operates in a cantilever-like bending mode and is capable of measuring forces up to 10 mN. It is demonstrated that the output of our microforce sensor is linear, in addition to which it can measure forces higher than 3 mN with a coefficient of variation of less than 2%. This new microforce sensor was integrated into a microrobotic platform and is shown to be able to accurately measure the Z-directional bond strength of paper fibers. [ABSTRACT FROM AUTHOR]

Titration method (dropping-on method) was introduced as an efficient approach for determining the mercury ion (Hg2+) concentration in aqueous solution by using fabricated cellulosic paper-based test strips. In this study, dithizone used as a recognition reagent was physically loaded on cellulosic paper-based test strips for Hg2+ selective recognition. The sensing mechanism was established on the spectral absorption rate of the coordination compound that was formed by dithizone and Hg2+ under strong acidic conditions. The calibration curve was obtained by the absorbency of Hg2+-dithizone complexes from different Hg2+ concentration solutions, and the correlation coefficient (R2) reached 0.9971. The detection range of the test trip for Hg2+ was obtained at 0.1 μg/mL to 30 μg/mL. Moreover, these superior cellulosic paper-based test strips have a rapid color-forming time (1.5 min) and low volume demand (3.7 μL samples at 0.0127 g/L dithizone recognition concentration). This portable paper-based test strip can give potential applications for field screening or on-site semiquantitative analysis. [ABSTRACT FROM AUTHOR]

Hydrogen sulfide (H 2 S) is a regulated industrial hazard, as it is a chemical asphyxiant with acute toxicity. The characteristic rotten egg smell of hydrogen sulfide is not a suitable indicator for the presence of the gas, as the olfactory system is often overwhelmed and desensitized to the gas. A new probe utilizing the copper(II) complex of 1-(2-pyridylazo)-2-naphthol (Cu-PAN) on a moist, porous, paper-like substrate has been developed to replace commercial lead acetate-based test papers for the detection of hydrogen sulfide gas at low concentrations. The reaction between H 2 S gas and the copper complex produces a distinct color change from purple to yellow/orange. The color change is observable to the naked eye for concentrations as low as 30 ppb H 2 S in a small, 1.35-L of gas, a typical volume of human breath. In comparison, the commercial Pb(II)(acetate) 2 test papers require large volumes of 5 ppm H 2 S gas. Incorporation of a base in the current probe aids in trapping weakly acidic H 2 S. The moist probe enhances the kinetics of the reaction between H 2 S gas and the base/Cu-PAN. These features increase the sensitivity of the probe, making it potentially suitable for both human breath tests and industrial H 2 S monitoring. The utilization of a handheld colorimeter allows for quantitative analysis of gaseous H 2 S, with a limit of detection (LoD) of 16 ppb and a limit of quantification (LoQ) of 53 ppb. The probe, offering rapid detection, is easy to prepare, inexpensive, disposable, and a green alternative to the commonly used lead acetate test papers. [ABSTRACT FROM AUTHOR]

Abstract: The automatic control of product moisture content in the paper industry is based upon online moisture measurement. Furthermore, the automatic control of other quality variables such as coat weight may also rely on the moisture measurement. The integrity of infrared radiation (IR) based online moisture measurement systems was studied by performing basic calibrations at the mills with references sealed between two glass plates. The calibrations were performed according to the EN ISO/IEC 17025 standard which is a requirement for calibration laboratories. The observed measurement errors were 2.9% moisture in the first time calibrations at the 95% confidence level. It is demonstrated that these errors can be reduced to under 0.5% moisture by applying traceable methods in the basic calibration, thus improving the integrity of online moisture measurements. Also a standardised algorithm, based on the experience from the performed calibrations, is proposed to ease the adjustment of different moisture measurement systems. [Copyright &y& Elsevier]

In this work, a colorimetric microfluidic paper-based analytical device (μPAD) combined with a smartphone readout was proposed for the determination of serum iron (Fe3+), which is linked to transferrin. Firstly, Fe3+ was selectively isolated and preconcentrated from serum by using anti-transferrin immunomagnetic beads (anti-Tf-MBs). Secondly, Fe3+ is reduced to Fe2+ by a hydroxylamine solution (pH 4.8) and then measured in the μPAD, which contains the colorimetric reagent ferrozine. Finally, the intensity of the purple color formed in the μPAD was measured by a smartphone. The approach exhibited an excellent linear correlation (r = 0.996) and good limit of detection (0.3 μg mL−1). Moreover, a certified reference material (human serum) was analyzed by this approach, showing an excellent accuracy (E r < 4%) and inter-device reproducibility (RSD = 1%, n = 3). Interestingly, the μPAD array-design allowed the simultaneous analysis of different samples, improving the sample throughput (up to 5 samples in 130 min, using 100 μL each), and the integration of calibration and analysis into the same device, simplifying the analysis without losing accuracy or sensitivity, and avoiding inter-device variability, which constituted an added value to this approach. These disposable μPADs meet several requirements of point-of-care testing (POCT) because it is cheap, portable, easy-to-use, sensitive, and specific. Therefore, it may be an interesting way for measuring patients' serum iron levels in situ with reliability, especially, in developing countries, where the prevalence of iron deficiency and iron-deficiency anemia is higher and there are lower health resources than in developed countries. [Display omitted] • A colorimetric μPAD with smartphone reading was developed for serum iron determination. • Anti-transferrin immunomagnetic beads were used for iron isolation and preconcentration. • Calibration and analysis were integrated on board the same μPAD. • The method was validated by analyzing a certified reference material (human serum). • The approach showed excellent accuracy (error <4%) and precision (RSD = 1%). [ABSTRACT FROM AUTHOR]