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Major modifications are made to the setup and signal processing of the method of in-situ measurement of the pitch of a diffraction grating based on the angles of diffraction of the diffracted optical frequency comb laser emanated from the grating. In the method, the improvement of the uncertainty of in-situ pitch measurement can be expected since every mode in the diffracted optical frequency comb laser can be utilized. Instead of employing a Fabry-Pérot etalon for the separation of the neighboring modes in the group of the diffracted laser beams, the weight-of-mass method is introduced in the method to detect the light wavelength in the Littrow configuration. An attempt is also made to reduce the influence of the non-uniform spectrum of the optical comb laser employed in the setup through normalization operation. In addition, an optical alignment technique with the employment of a retroreflector is introduced for the precise alignment of optical components in the setup. Furthermore, a mathematical model of the pitch measurement by the proposed method is established, and theoretical analysis on the uncertainty of pitch measurement is carried out based on the guide to the expression of uncertainty in measurement (GUM).

Peripheral fatigue results from multiple electrochemical and mechanical events in the cell body and the muscle-tendon complex. Combined force and surface electromyographic signal analysis is among the most widely used approaches to describe the behaviour of a fatigued muscle. Advances in technologies and methodological procedures (e.g. laser diffraction, 31P magnetic resonance spectroscopy, shear-wave elastography, tensiomyography, myotonometry, mechanomyography, and high-density surface electromyography) have expanded our knowledge of muscle behaviour before, during, and after a fatiguing task. This review gives an update on recent developments in technologies for investigating the effects of peripheral fatigue linked to skeletal muscle contraction and on mechanistic insights into the electrochemical and mechanical aspects of fatigue. The salient points from the literature analysis are: (1) the electrochemical and mechanical events in the cell (alterations in cross-bridge formation and function and in depolarization of the tubular membrane) precede the events taking place at the muscle-tendon complex (decrease in muscle-tendon unit stiffness); (2) the changes in the fatigued muscle are not homogenous along its length and width but rather reflect a functional compartmentalisation that counteracts the decline in performance; (3) fatigue induces changes in load sharing among adjacent/synergistic muscles. A focus of future studies is to observe how these regional differences occur within single muscle fibres. To do this, a combination of different approaches may yield new insights into the mechanisms underlying muscle fatigue and how the muscle counteracts fatigue. [ABSTRACT FROM AUTHOR]

The determination of particle size distribution is a crucial issue in various fields of earth sciences (e.g., Quaternary research, sedimentology, stratigraphy, structural geology, volcanology), environmental sciences as well as diverse industrial applications (e.g., pharmaceuticals, cement industry). New measurement techniques developed as a result of industrial demands have also gained ground in environmental and Earth sciences research. The new techniques (especially laser diffraction) have enabled the particle characterisation in the broader size-range with a more detailed resolution. Still, they have to be compared with data obtained by classical methods. In light of the above, the primary aim of our research is to examine the methods of particle size determination critically. Excessive oversimplifications of particle size analyses routinely have used in paleo-environmental and paleo-climatological reconstructions, and other sedimentary studies, as well as insufficient knowledge of the background of the applied methods, distort the interpretation of the results. Over the past four decades, laser diffraction particle size analysers have proven to be practical tools of particle size characterisation. However, the shape of the natural sediment and soil particles are irregular and, therefore, affects the particle size distribution results obtained by different methods. The results of the traditional pipette method differed from laser diffraction results. The presence or absence of the pretreatments did control the differences between the two techniques. The results of Fraunhofer optical method were significantly different from Mie theory because it can detect much lower volume percentages of finer particles. Grain size results of coarse-grained samples measured by different laser diffraction devices were more comparable than the results of more clayey samples. The ratios of different sizes were changed due to the hydrochloric acid and hydrogen peroxide pretreatments. The comparison of different techniques is necessary to revaluate standards in grain size measurements which can enable the shift from conventional methods to more productive and reproducible methods. Still, light scattering techniques have not yet been able to displace classical methods in Earth sciences completely, in contrast to industrial applications. [ABSTRACT FROM AUTHOR]

Nozzle flowrate and spray pressure are two of the most important factors influencing on droplet characteristics. With the aim to develop prediction models for air-induction nozzles (AINs), a series of Billericay Farm Services (BFS) AINs with different orifice diameters in combination with tap water were tested. 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.6 MPa and 0.7 MPa of spray pressures and 2 m/s, 3 m/s, 4 m/s and 5 m/s of air speeds were setup. Based on the wind tunnel tests data, prediction models with input variables of nozzle flowrate and spray pressure and output variables of Dv0.1, Dv0.5, Dv0.9, %<150 µm (proportion of spray volume contained in droplets with diameter below 150 µm), relative span (RS) and coefficient of variation (CV) of Dv0.5 were developed. The developed models were validated based on wind tunnel experimental data. Results showed that: for Dv0.1, Dv0.5, Dv0.9 and %<150 µm, R² were equal to 0.768, 0.823, 0.868 and 0.811, indicating that the predictive ability for these four parameters is strong. For RS and CV, R² were equal to 0.100 and 0.113, respectively, indicating that the predictive ability for these two parameters is poor. The models developed in the present study are helpful for facilitating the use of AIN in agricultural spray application. [ABSTRACT FROM AUTHOR]

There are global aspirations to harmonize soil particle- size distribution data measured by the laser diffraction method and by traditional sedimentation techniques, e.g. sieve-pipette methods. The need has arisen therefore to build up a database, containing particle-size distribution values measured by the sieving and pipette method according to the Hungarian standard (sieve-pipette methods-MSZ) and the laser diffraction method according to a widespread and widely used procedure. In our current publication, 155 soil samples measured with sieve-pipette methods-MSZ and laser diffraction method (Malvern Mastersizer 2000, HydroG dispersion unit) were compared. Through the application of the usual size limits at the laser diffraction method, the clay fraction was under- and the silt fraction was overestimated compared to the sieve-pipette methods-MSZ results, and subsequently the soil texture classes were determined according to the results of both methods also differed significantly from each other. Based on our previous experience, the extension of the upper size limit of the clay fraction from 2 to 7 µm increases the comparability of sievepipette methods-MSZ and laser diffraction method, in this way the texture classes derived from the particle-size distributions were also more in accordance with each other. The difference between the results of the two kinds of particle-size distribution measurement methods could be further reduced with the pedotransfer functions presented. [ABSTRACT FROM AUTHOR]

Liposomes are potent adjuvant constituents for licensed vaccines and vaccine candidates and carriers for drug delivery. Depending on the method of preparation, liposomes vary in size distribution, either forming uniform small size vesicles or a heterogeneous mixture of small to large vesicles. Importantly, differences in liposomal size have been demonstrated to induce differential immune responses. Determination of particle size distribution could therefore be crucial for the efficacy and stability of vaccine formulations. We compared the techniques of dynamic light scattering, laser diffraction, and conventional nanoparticle tracking analysis with a novel multispectral advanced nanoparticle tracking analysis (MANTA) for particle size determination of mono- and polydisperse liposomes. MANTA reported an average 146 nm size of monodisperse liposomes but showed a multimodal distribution of polydisperse liposomes with continuous sizes from 50 to 2000 nm. However, approximately 95% of particles were in the size range of 50–1500 nm and only few particles were identified in the 1500–2000 nm range for the investigated volume. Based on our results, we conclude that MANTA is the most suitable approach and can serve as stand-alone technique for particle size characterization of heterogeneous liposome samples in the 50–2000 nm size range. [ABSTRACT FROM AUTHOR]

Laser diffraction grain size data and size distributions of paleosols are widely used in paleoenvironmental reconstructions as physicochemical alteration-related proxies of past changes of the sedimentary environment. Different laser diffraction devices, optical theories, and optical settings are being applied nowadays, and ignorance of several uncertainty factors and drawbacks of this indirect grain size characterization approach has led to poorly comparable and reproducible granulometric datasets. Here we present a detailed comparison of grain size results acquired by three state-of-the-art, widely used laser diffraction devices (Fritsch Analysette 22 Microtec Plus, Horiba Partica La-950 v2 and Malvern Mastersizer 3000). Grain size distributions were calculated using both the Fraunhofer and Mie scattering theories and a wide variety of optical settings (68 different complex refractive indices: 1.45–1.6–0.01i-1i) for 10 samples from loess-paleosol sequences of the Carpathian Basin. Our findings demonstrate that optical settings have significant effects on grain size distributions, especially for the finest fractions (clay and fine silt populations). Interestingly, the selection of laser diffraction devices was an even more deterministic factor in grain size characterization as revealed by network analyses. Clustering of bulk and size-fractionated grain size records was primarily determined by the device used, and also by the applied optical settings. At the same time, the real physical differences of samples were found to be deterministic exclusively for the sand-sized fraction. As such, these findings emphasize the importance of the accurate description of applied methodological details in research papers, as comparability and reproducibility of granulometric datasets cannot be ensured with a lack of information about instrumental conditions and settings. [ABSTRACT FROM AUTHOR]

Abstract In the present work, the question how to obtain high-quality laser diffraction (LD) results is discussed by investigating various hurdles that can be encountered during particle size measurements in wet dispersions and the associated data interpretation. Following this an effective troubleshooting is discussed based on theoretical insight into the LD measurement. As an important element in the Mie theory, the refractive indices of the model compounds, bedaquiline and cinnarizine, were quantified using the LD software, the Becke line technique, and the single solvent technique, as described by Saveyn et al. [Saveyn H, et al. Part Part Syst Char. 2001;19:426-432]. The influence of parameters such as obscuration level, background quality, and fitting of data were investigated and a summative flow chart has been provided. Through this analysis the present work emphasizes the need for a systematic approach when conducting LD measurements, including standard performance of an obscuration titration and an extended method optimization, to reach high-quality LD results. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract The evaluation of particle size recommended in the pharmacopeias requires a constant flow rate, and the method for pediatric inhaled drugs is the same as for adult drugs. In this study, the aerosol concentration and particle size distribution (PSD) were measured under a realistic breathing pattern and constant flow. Two types of nebulizer (i.e., breath-enhanced nebulizer and vibrating-mesh nebulizer) and two formulations (i.e., budesonide suspension and albuterol solution) were chosen for comparison. The aerosol concentration under the realistic pattern was not constant, which was different from the result at constant flow. The changing trend of aerosol concentration varied with the operation process of each device. The aerosol concentration profile was similar between budesonide suspension and albuterol solution. As to the PSD, as inspiratory flow increased, the X50 (50% undersize) increased with all nebulizers but Omron microAir NE-U22 nebulizer. There was good agreement between X50 obtained under the realistic inhalation patterns and their equivalent average flow rates by Bland-Altman analysis, although the X50 obtained under the realistic inhalation pattern was greater than value at constant flow. The agreement of the two breath-enhanced jet nebulizers was better than that of the vibrating-mesh nebulizers. The X50 of budesonide was not equal to that of albuterol when using the same nebulizer. Interestingly, a significant difference was observed in the X50 and Span when comparing the results of PSD under adult and child breathing patterns. Furthermore, all vibrating-mesh nebulizers produced aerosol droplets having larger mean diameter and narrower size distribution than those of the air-jet nebulizers. We conclude that it will be more conducive to the evaluation of particle size to use a laser diffractometer under a realistic pattern and make up for the shortcomings of cascade impactors. The effects of flow pattern, nebulizer and formulation should be taken into account in the evaluation of the qualities of nebulizer products in pharmaceutical practice. [ABSTRACT FROM AUTHOR]

Suspension plasma spray (SPS) is an emerging coating process for making surfaces with superior properties. In this process, in-flight spray particle characteristics such as size, velocity, and temperature have a direct influence on the properties of the deposited coatings. Accordingly, online diagnostic tools to characterize the in-flight particles in the SPS are sought by research laboratories and industrial centers for process optimization and control. However, small particle size, high temperature, and radiation of the plasma make it challenging to carry out these measurements. In this study, we used a light diffraction (LD) approach to measure online the size of in-flight particles sprayed from a well-predefined size distribution. Laser beam refraction by the hot plasma/gas jet is one of the main sources of noise for such size measurement. Successful measurements were achieved by shielding the measurement section and filtering the plasma radiation to reduce the influence of the laser refraction and plasma radiation. Results showed that the LD method has the potential to be used to monitor online the size distribution of in-flight particles in the SPS process. [ABSTRACT FROM AUTHOR]

Particle size distribution (PSD) is among basic parameters in soil and sediment characterization and provides essential information in sedimentological and environmental studies. The problem with the PSD determination is that for any given sample the result depends not only on the method used but also on the sample pre‐treatment, making them seldom comparable. In this study, the PSD of seven non‐treated and pre‐treated soil samples were determined by four granulometric methods (pipette, sedigraph, particle counter and laser diffraction analysis). Samples were subjected to pre‐treatments commonly used in sample preparation for the PSD determination, i.e., addition of dispersant (sodium metaphosphate) and removal of the organic matter (with hydrogen peroxide). The total organic carbon (TOC) analysis was used to estimate the content of organic matter before and after its removal. The effect of different pre‐treatments was evaluated based on the PSD variations and the changes in the specific surface area (SSA) of the samples. The results highlighted differences in the PSD curves of samples depending on the granulometric method and pre‐treatment applied. The most pronounced difference was the higher amount of clay fraction determined by settling techniques. The role of hydrogen peroxide in disruption of aggregates was evident in the increase in the SSA as well as the share of fine fraction determined by all four techniques, while sodium metaphosphate made no modifications of the SSA but acted in favour of prolonging settling of clay particles and increasing its content obtained by settling techniques. [ABSTRACT FROM AUTHOR]

Abstract A method for characterizing aggregate stability with repeated laser diffraction measurements was tested on soils spanning the prairie-forest ecotone in northern Minnesota, USA. These soils formed in similar parent material but display a wide range of upper horizon morphology, organic carbon content, and chemistry, allowing assessment of the method's performance over a wide range of aggregate stability and its utility in identifying factors influencing aggregate behavior. Equations representing fine material release through breakdown of two aggregate populations as first-order processes were fit to experimental data. The best-fit parameters for these equations, and an additional index of persistent water-stable aggregate content, indicated distinct differences in aggregate behavior among the major horizons of Mollisols and Alfisols. Linear models were developed to explore the relationships between these parameters and soil physicochemical characteristics for the dataset as a whole and for subsets corresponding to four zones with different vegetation history, soil orders, and major soil horizons. The relationships identified were relatively weak (R2 = 0.30 to 0.70). The best predictors for the parameters representing early disintegration of less stable aggregates were cation exchange capacity (CEC) and effective CEC (ECEC) for the whole dataset, although organic carbon and nitrogen contents also emerged as predictors for forest and Alfisol subsets. The best predictors for the index of persistent water-stable aggregate content were organic carbon content, base saturation, or exchangeable Ca/Mg ratio, depending on the particular subset and fine material size fraction used in the analysis. The relatively weak explanatory power of organic carbon content as a predictor of aggregate behavior in these experiments was somewhat surprising, given prior work on aggregate stability. Both CEC and ECEC may serve as proxies for the various combinations of organic matter and clay content that influence aggregate stability in these samples, explaining their importance as predictors. It is likely that other factors not examined in this research contributed to aggregate stability, including carbonate content, clay mineralogy, and differing frequency and types of pedoturbation under grassland and forest. The results of this study are relevant to reconstructing the development of texture-contrast profiles as forest invaded grassland over the past 4000 in the study area, as documented by paleoecological research. In particular, loss of organic matter below a thin A horizon may have facilitated initial development of an E horizon in which weak aggregation favored clay eluviation; loss of clay would then have weakened aggregate stability still further. We suggest this new method for assessing aggregate stability can also be applied to research on soil erosion and runoff potential as affected by land use and management. Highlights • Soil aggregate behavior assessed using repeated laser diffraction measurements. • Dynamics of aggregate disintegration can be modeled as first-order processes. • Method applied to comparison of aggregate behavior in grassland and forest soils. • Aggregate's stability and disintegration dynamics vary by soil order and horizon. • Disintegration rates and water-stable aggregate content related to soil properties. [ABSTRACT FROM AUTHOR]

The hydrosedimentological monitoring with reliable data of suspended sediment concentration can be problematic when conventional methods are employed because these methods usually show measurements with stations and frequencies lower than desirable, therefore limiting the studies and the management of water resources. In this context, this paper shows a study carried out in the Mogi-Guaçu reservoir (São Paulo, Brazil) in which the correlation of data from sediment in suspension concentration was made, measured with automatic device (LISST-100X) and conventional sampling. By linear regressions and statistical tests, the efficiency of laser diffraction technique was assessed, and the concentrations of suspended sediments were estimated, for both of the performed campaigns. Through the statistical analysis of the results, it was possible to confirm that among all scenarios of linear regressions adopted, the model that divides the reservoir in sectors shows better concentration estimates, inferring that the concentration of suspended sediment has a characteristic behaviour of the segment of the Mogi-Guaçu reservoir. Therefore, the LISST-100X herein proved to be feasible for the case study. It should be noted that the use of this probe made it possible to obtain more data than those obtained using conventional techniques, enabling a more complete analysis of the reservoir and significantly reducing the work in the field, laboratory and office. [ABSTRACT FROM AUTHOR]

In this study, the particle size distribution (PSD) of the soil sediment from topsoil obtained from soil erosion experiments under different conditions was measured. Rainfall simulators were used for rain generation on the soil erosion plots with slopes 22°, 30°, 34° and length 4.25 m. The influence of the external factors (slope and initial state) on the particle and aggregate size distribution were evaluated by laser diffractometer (LD). The aggregate representation percentage in the eroded sediment was also investigated. It has been found that when the erosion processes are intensive (steep slope or long duration of the raining), the eroded sediment contains coarser particles and lower amounts of aggregates. Three methods for the soil particle analyses were tested: (i) conventional–sieving and hydrometer method; (ii) PARIO Soil Particle Analyzer combined with sieving; and (iii) laser diffraction (LD) using Mastersizer 3000. These methods were evaluated in terms of reproducibility of the results, time demands, and usability. It was verified that the LD has significant advantages compared to other two methods, especially the short measurement time for one sample (only 15 min per sample for LD) and the possibility to destroy soil aggregates using ultrasound which is much easier than using hexametaphosphate.

While the concept of microplastic (<5 mm) is well-established, emergence of nanoplastics (<1000 nm) as a new contaminant presents a recent and evolving challenge. The field of nanoplastic research remains in its early stages, and its progress is contingent upon the development of reliable and practical analytical methods, which are currently lacking. This review aims to address the intricacies of nanoplastic analysis by providing a comprehensive overview on the application of advanced imaging techniques, with a particular focus on Raman imaging, for nanoplastic identification and simultaneous visualisation towards quantification. Although Raman imaging via hyper spectrum is a potentially powerful tool to analyse nanoplastics, several challenges should be overcome. The first challenge lies in the weak Raman signal of nanoplastics. To address this, effective sample preparation and signal enhancement techniques can be implemented, such as by analysing the hyper spectrum that contains hundred-to-thousand spectra, rather than a single spectrum. Second challenge is the complexity of Raman hyperspectral matrix with dataset size at megabyte (MB) or even bigger, which can be adopted using different algorithms ranging from image merging to multivariate analysis of chemometrics. Third challenge is the laser size that hinders the visualisation of small nanoplastics due to the laser diffraction (λ/ 2NA, ∼300 nm), which can be solved with involving the use of super-resolution. Signal processing, such as colour off-setting, Gaussian fitting (via deconvolution), and re-focus or image re-construction, are reviewed herein, which show a great promise for breaking through the diffraction limit. Overall, current studies along with further validation are imperative to refine these approaches and enhance the reliability, not only for nanoplastics research but also for broader investigations in the realm of nanomaterials. [Display omitted] • Unique characteristics of nanoplastics complicate extraction and detection. • Combining microscopy and spectroscopy is recommended for nanoplastic analysis. • Raman imaging is a promising method for reliable characterisation of nanoplastics. • Several algorithms are useful in converting a hyperspectral matrix to an image. • Image re-construction via Gaussian fitting helps break through diffraction limit. [ABSTRACT FROM AUTHOR]

The particle size of milled ingredients influences the quality and texture of manufactured foods. However, the limited understanding of how milling influences particle size distribution (PSD) of pulse flours, has hindered the incorporation of pulses in food formulations. This first-ot-its-kind study delves into PSD examination of roller-milled yellow pea flour streams and blends, employing laser diffraction (LD), scanning electron microscopy (SEM), and synchrotron-based X-ray microcomputed tomography (SR-μCT). LD analysis revealed a multimodal distribution pattern across particle sizes ranging from 3 to 1300 μm. SEM confirmed particle size variations among flour streams and blends. Synchrotron X-rays, known for their high intensity, brightness, and tunable energy, provided seminal insights into complex flour structures. Employing SR-μCT, the 3D volumetric particle size distribution yielded more accurate particle size and shape computations than established techniques. This pulse flour characterization will enable food manufacturers to utilize nutrient-dense pulse ingredients to address the growing market demand for health-conscious products. [Display omitted] • Synchrotron-based X-ray micro-computed tomography aided in 3D flour particle models. • Particle size distribution (PSD) differed among flour streams and blends. • Comprehensive PSD analysis yielded seminal microstructural details of pea flour. • Flour streams had a higher particle count than blends in the specified range. [ABSTRACT FROM AUTHOR]

The present study analyze the effects of sample preparation and data analysis techniques for different experimental methods of metal powder characterization. The aim is to propose a robust strategy for quantifying powder particle size distribution and morphology of relevance for metal additive manufacturing (MAM) processes, in particular for powders with nearly spherical particle shape. Laser diffraction (LD), scanning electron microscopy (SEM) and high-resolution X-ray computed tomography (XCT) are used to analyze three different stainless-steel 316L powders. The results obtained demonstrate that the powder sample itself and the sample preparation, both have a significant effect on the obtained values. For the imaging processing methods, the post-processing route is an important part of the characterization and strongly affects the results. However, proper sample preparation is shown to ease this post-processing. Given the high sphericity of the powders used, it is shown that 2D and 3D methods generally lead to the same result when the 2D data are properly transformed to 3D space. Guidelines to overcome the shortcomings of the different techniques are suggested. [Display omitted] • The importance of sample preparation and analysis procedures. • Possibilities and limitations of 2D to 3D data transformation for PSD. • Multi-technique for enhanced characterization. [ABSTRACT FROM AUTHOR]

The paper deals with particle analysis and the evaluation of the shape and size distribution of micro- to nano-sized quartz particles as a key parameter for the evaluation of quality in many industrial fields, particularly for high-purity applications. Samples are analyzed by laser diffraction, the most commonly used method for determining the size of the particles; for precise measurement with the possibility of high-resolution imaging of particles, scanning electron microscopy was applied. For morphological and size analysis of electrically non-conductive micro- to nano-particles under environmentally compatible conditions of elevated gas pressure and humidity, environmental scanning electron microscopy was selected as the most suitable. Moreover, the high-end methods of focused ion beam scanning electron microscopy and serial block-face scanning electron microscopy enabled the analysis of particles in the epoxy resin volume including spatial imaging. The application of image post-processing as an important part of the electron microscopy workflow is also discussed. [Display omitted] • Shape analysis and particle size distribution of nano to micro quartz particles. • Comparison of laser diffraction and other advanced electron microscopic methods. • Image post-processing is an important part of analysis when using microscopic methods. • Environmental scanning electron microscopy used as a complex particle analysis method. [ABSTRACT FROM AUTHOR]

Dust explosion hazards can be analyzed by various explosion parameters, which are known to depend on the particle size distribution of combustible dust. Literature has evidenced the dispersion system in laboratory apparatus (e.g., 20-L chamber) breaks the original dust into smaller sizes. Such unexpected particle breakage can lead to misleading explosion results which may exaggerate the actual hazards. This study develops a novel solution to identify combustible particle breakage by exploiting dry dispersion laser diffraction technology. Nine samples were dispersed under different levels of energy in a particle size analyzer. Serious particle breakage is confirmed if the tested particle size decreases significantly with increasing dispersion pressure. Eight particle size parameters were plotted to derive quantitative pressure titration curves. A larger average slope in percentage decreases of D 10 , D 50 , and D 3,2 represents a higher particle breakage tendency. The characterization results are well correlated to previous breakage classification in the 20-L chamber. [Display omitted] • A new approach via laser diffraction is proposed to identify particle breakage due to dispersion. • Results are well correlated to previous particle breakage classification performed in the 20-L chamber. • Combustible dusts can be categorized into three breakage classes: BCI, BCII and BCIII. • It is suggested to apply the approach during the stage of sample characterization in laboratory tests. [ABSTRACT FROM AUTHOR]

Fine aggregate is one of the essential components in concrete and significantly influences the material properties. As parts of natures, physical characteristics of fine aggregate are highly relevant to its behaviors in concrete. The most of previous studies are mainly focused on the physical properties of coarse aggregate due to the equipment limitations. In this paper, two typical fine aggregates, i.e. river sand and crushed rock, are selected for shape characterization. The new developed digital image analysis systems are employed as the main approaches for the purpose. Some other technical methods, e.g. sieve test, laser diffraction method are also used for the comparable references. Shape characteristics of fine aggregates with different origins but in similar size ranges are revealed by this study. Compared with coarse aggregate, fine grains of different origins generally have similar shape differences. These differences are more significant in surface texture properties, which can be easily identified by an advanced shape parameter: bluntness. The new image analysis method is then approved to be efficient for the shape characterization of fine aggregate in concrete.

The article presents hazardous conditions of airborne dust based on the results of measurements of dust concentration taken at work-places at a underground rock-coal face drilled by a heading machine with combined ventilation (suction and forced ventilation with dust collector). The measurements were taken using three methods in order to examine and assess the actual conditions within the excavation subject to the study. The measurement results and conclusions show major difficulties in achieving MAC levels. Research conclusions indicate the low efficiency of collective and personal measures applied to protect against dust harmful to health as well as the need to improve them.

Aim of Study: The use of a nebulizer paired with high-flow nasal cannulas (HFNC) has been proposed for drug delivery in bronchiolitis. Particle size nebulized is a relevant factor determining the efficacy of the nebulization. We replicated in vitro the theoretical parameters most widely used in bronchiolitis and we compared the size of the droplet nebulized with a standard nebulizer and a nebulizer integrated into HFNC. Materials and Methods: We used laser diffraction to analyze the particle size nebulized (volume median diameter Dv50). The standard system was a jet nebulizer connected to a facemask with a flow rate of 8 L/min (JN). Three designs were used as nebulizers integrated into HFNC: a vibrating mesh nebulizer set 1) before (HFNC-BH) and 2) after (HFNC-AH) the humidifier, and 3) a jet nebulizer connected before the nasal cannula (HFNC-BNC). HFNC was used with neonatal (3–8 L/min) and infant cannulas (8–15 L/min). Results: Droplet size was similar among the three drugs studied. A lower particle size was obtained when using the nebulization system integrated into HFNC compared to the standard nebulizer, regardless of the flow rate and the nasal cannula used when the position of the nebulizer was before the nasal cannula (p < 0.05): 6.89 µm (JN), 2.49 µm (HFNC-BNC 3 L/min), 2.59 µm (HFNC-BNC 5 L/min), 2.44 µm (HFNC-BNC 8 L/min), 3.22 µm (HFNC-BNC 10 L/min), 3.23 µm (HFNC-BNC 13 L/min), 3.16 µm (HFNC-BNC 15 L/min). The particle size was lower in HFNC-BF compared to the HFNC-AH using neonatal nasal cannula (3–8 L/min) (p < 0.05). Conclusion: The use of a nebulizer integrated with HFNC has shown promising results in an experimental scenario of bronchiolitis. The particle size achieved with the nebulizer placed before the humidifier is equivalent to the one obtained via conventional nebulization, and it is even smaller when the integrated nebulizer is placed before the nasal cannulas. [ABSTRACT FROM AUTHOR]

Abstract Two polydisperse, non-spherical certified reference materials consisting of corundum particles with sizes between 1 μm and 8 μm and 15 μm and 80 μm were prepared. Homogeneity was assessed using a dedicated study, as well as data from the characterisation exercise and was found sufficient. The materials were characterized with respect to their particle size distribution in interlaboratory studies. Certification was performed for selected percentiles of the cumulative distribution of the number-weighted area-equivalent circular diameter by static image analysis and for selected percentiles of the cumulative distribution of the volume-weighted equivalent spherical diameter by laser diffraction. Relative expanded assigned uncertainties ranged from 1.1% to 8.9% for laser diffraction, confirming that, for the given materials, instruments of different manufacturers do not provide different results. Relative expanded assigned uncertainties for image analysis were significantly larger than for laser diffraction and ranged from 8% to 23%. These uncertainties are considerably larger than the fundamental sampling error and indicate that unaccounted effects may be attributable to sample preparation and non-sphericity of particles may have a large effect on the reliability of image analysis. Graphical abstract Unlabelled Image Highlights • Two certified reference materials from non-spherical, polydisperse corundum produced. • Very good agreement was achieved for laser diffraction among instruments of different producers. • Expanded uncertainties are small enough to demonstrate of accuracy within the limits of ISO 13320. • Variation for static image analysis are higher than reported for spherical particles. [ABSTRACT FROM AUTHOR]

Highlights • Automated optical methodologies can provide in depth analysis of particle size and shape. • Lased diffraction is in better agreement with automated optical methodologies than sedimentation methods are. • A comparative study shows that traditional techniques present limitation for particle size analysis. • Confirmation of the offset between sedimentation and laser. Abstract For many years papers have been published showing differences between sedimentation-based methods against laser diffraction. Differences were found especially in the fine texture ranges and regression equations were presented to convert data obtained between different methods. In this paper we aimed at understanding which method is closer to an independent measurement of particle size. We selected a new, automated image analysis technique as a reference method. Since with this new method each individual particle is photographed, its pixels counted and its shape analysed, we assumed this method as the reference method against which test the accuracy of sedimentation methods and laser diffraction. Comparison showed that laser diffraction was in better agreement with the independent optical methods, indicating that the sedimentation methods tend to largely overestimate the finer fractions of the distribution. Considering the results presented in this research, and the methodological disadvantages of sedimentation methods, we propose to employ laser diffraction as a standard method for particle size analysis in soils. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Charge due to oxidation of copper in KOH solution was used to estimate surface area. • Charge due to stripping of monolayer of Pb was used to estimate surface area. • The surface area of copper powder estimated by copper oxidation was 611 cm2/gm. • The surface area of copper powder estimated by stripping Pb was 675 cm2/gm. Abstract For heterogeneous catalytic/electrocatalytic reaction systems, estimation of the surface area of the catalyst is of great importance. As far as systems involving copper as catalyst are concerned, the literature reveals lack of a robust method to determine the surface area. In this work, we compare the surface area determined from electrochemical measurements, optical and electron microscopy and from laser diffraction experiments. Specifically, cyclic voltammetry in two different solutions involving two separate surface reactions has been used to measure the surface area. First involves the formation of a monolayer of Cu 2 O and the second involves formation of a monolayer of Pb. Additionally, the surface area was also estimated from the double layer capacitance of the copper electrode. The surface areas determined from these electrochemical measurements are in good agreement with those obtained from microscopy and particle size analyzers (for average copper particle diameter = 10 µm). [ABSTRACT FROM AUTHOR]

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Highlights • Image analysis is suitable for determining the specific surface area of fly ash. • Blaine air permeability test underestimates the specific surface area of fly ash. • Nitrogen absorption test overestimates the specific surface area of fly ash. • Laser diffraction test is affected by the material chemical composition. • Laser diffraction test underestimates the specific surface area of porous fly ash. Abstract The specific surface area (SSA) of fly ash has a significant effect on its pozzolanic reactivity and on the performance of fly ash-blended concrete. Because fly ash contains a considerable amount of irregularly shaped particles and unburned carbon, determination of an accurate SSA is analytically troublesome by conventional methods. Various methods for determining the SSA of fly ash are evaluated and compared in this study, including Blaine air permeability, nitrogen absorption testing, laser diffraction testing and image analysis. The experimental results show that Blaine air permeability and laser diffraction testing tend to underestimate the SSA of fly ash because they involve the assumption of perfectly spherical particle geometry. The SSA determined by nitrogen absorption testing is found to be associated with a significant overestimation induced by unburned carbon. Image analysis coupled with BSE appears to give consistent results and appears to be the most promising method of determining an accurate value for absolute SSA. [ABSTRACT FROM AUTHOR]

Laser diffraction is among the most widely used methods for spray droplet size measurements. However, the so-called beam-steering effect must be considered when pneumatic atomizers are used for droplet generation. The beam-steering effect is a systematic measurement error, leading to the detection of apparent large spray droplets due to gradients in the refractive index of the gas phase. The established correction method is based on the reduction of the laser diffraction system's measurement range by deactivation of detectors, relevant for the detection of large droplets. As this method is only applicable when size ranges of real and apparent droplet sizes are clearly different, an alternative method for beam-steering correction is introduced in the presented study. It is based on a multimodal log-normal fit of measured spray droplet sizes. The modality representing the largest droplets is correlated to the beam-steering effect and therefore excluded from the measured size distribution. The new method was successfully applied to previously published droplet size distribution measurements of an internal mixing Air-Core-Liquid-Ring (ACLR) atomizer. In measurements where the method of detector deactivation is applicable, excellent accordance of droplet size distributions, gained by both correction methods, was found. In measurements with overlapping real and apparent parts of the distribution, the new correction method led to a significant reduction of overestimated large droplets. As a consequence, we conclude that the new method presented here for beam-steering correction should be applied in laser diffraction measurements of spray droplet sizes, generated by pneumatic atomizers. [ABSTRACT FROM AUTHOR]

This work presents a new method for an online measurement of particles detached from a starch fouling layer during a cleaning process. This was achieved by designing the Automated Particle Analyser for Cleaning (APAC) by combining a flow channel with a laser diffraction particle size analyser. A method for the online measurement of particle size for different sets of parameters (flow velocity, temperature and addition of Sodium Hydroxide) was developed, monitoring cleaning progress and behaviour. The influence of the variation of the parameters on the progress of cleaning as well as their balance could be shown. Low temperature or velocity cause increasing cleaning time and vice versa. Overall detachment of small particles indicating cohesive failure could be observed as characteristic for starch based fouling layers. A narrow particle size distribution (PSD) of small particles indicates a cohesive failure and a steady disintegration of the fouling layer from top to bottom. On the contrary a PSD of larger size and broader shape prevails for adhesive failure and detachment of large patches of the fouling layer. [ABSTRACT FROM AUTHOR]

Two-level arrays of colloidal particles have been obtained using the method based on an intermittent, ‘‘stick–slip’’ motion of the meniscus during colloidal suspension evaporation. The ethanol suspension of monodisperse polystyrene microspheres of about 1 μm in size was prepared by emulsifier-free emulsion polymerization of styrene with potassium persulphate as an initiator. The resulting structures consist of parallel monolayer stripes of deposited microspheres, repeated with a period of 140–150 μm, and empty spaces between them. The microspheres are packed into a hexagonal structure inside the stripes. Laser diffraction patterns have been demonstrated for both levels of ordering, i.e., for the hexagonal structure at the first level and for the parallel stripes at the second level. [ABSTRACT FROM AUTHOR]

The objective of this research was to examine the influence of energy input on the particle size distribution of disintegrated sludge. The change of particle size distribution indicates the deagglomeration of flocs and disruption of micro-colonies. As the digestibility of sludge increases with dispersion, particle size analysis is an important factor in evaluating the disintegration process. Four different levels of energy input were used in the research: 10-100 kWh⋅m-3. All samples showed significant changes as far as dispersion (kdCST = 22.98-74.67, kdFCOD = 3.23-18.46), lysis (kdSCOD = 4.22-12.09), acidification (kdVFAs = 1.78-12.61), nitrogen release (kdTN = 4.02-21.61) indicators were concerned. Results indicate the gradual decrease of measured particle size with increasing energy input. The energy supplied to the disintegration process primarily promotes deagglomeration and with the rise of energy input, the destruction of cells. For EV = 50 and 100 kWh⋅m-3 an increased occurrence of lysis effects and increase in particle fraction <99.9 µm was noted. The highest efficiency evaluated by increase of filtered chemical oxygen demand (FCOD) and soluble COD (SCOD) per unit of volumetric energy - ΔCOD and ΔSCOD (mgO2⋅Wh-1) was obtained for Ev = 10 WhL-1, which corresponds to the most significant change in particle size distribution. The volume of particles <99.9 µm rose from 1.92% for non-disintegrated sludge to 26.62% for volumetric energy 100 kWh⋅m-3. [ABSTRACT FROM AUTHOR]

Purpose: Methods for particle size distribution (PSD) determination by laser diffraction are not standardized and differ between disciplines and sectors. The effect of H2O2 pretreatment before a sonication treatment in laser diffraction analysis of soils and marine sediments was examined on soils with less than 1% C and some marine sediments.Materials and methods: The method uncertainty for particle size analysis by the laser diffraction method using or not using H2O2 pretreatment followed by 2 min ultrasound and 1-mm sieving was determined for two soil samples and two aquatic sediments by analyzing ten replicates on a Malvern M2000 instrument. The carbon content was in the normal range for upland soils 0.1-0.9% C, but one of the aquatic sediment samples had a high carbon content (16.3% C) for which the H2O2 pretreatment was not feasible.Results and discussion: The effect of H2O2 pretreatment on the PSD was small and not significant. The standard deviation (std) in particle size fractions increased with particle size. PSDs and std for some samples were presented for future reference. Similar to other studies, the content of clay and silt (by sieving/hydrometer, SHM) was lower by the laser diffraction method (LDM) than by the hydrometer method. To avoid confusion, LDM results for the < 2-μm fraction should not be reported as a clay fraction to be used in texture classification. The absolute standard deviation of within-bin class was well below 1% in the colloidal fractions (using 2, 6, 8, and 20 μm bin delimitations) and below 0.2-3% in the sand fractions.Conclusions: The LDM method requires new calibrated transfer functions for classification of soil textural class due to deviating results for colloidal fractions. It can be used without H2O2 pretreatment on soils containing less than about 1% C, but results should be corrected for 1-2-mm coarse sand content if higher than, e.g., 5%. If the analysis is not referring to a particular volume of sample, the correction for 1-2-mm material can be omitted. [ABSTRACT FROM AUTHOR]

In this study, we examined lyotropic intrinsic cholesteric phase properties of some amino acid-based chiral surfactants, with partly fluorinated and hydrogenated chains, to investigate the effect of the twist structure of fluorocarbon chain on the helical twisting power of chiral surfactants. We synthesized some chiral and achiral surfactants, and their fluorinated/hydrogenated counterpart surfactants, taking into account the rule that [1 CF 2 = 1.5 CH 2 ]. We prepared lyotropic mixtures exhibiting discotic cholesteric phases by dissolution of chiral surfactants l -alaninehydrochloride undecylester ( l -AUnDE), l -serinehydrochloride undecylester ( l -SUnDE) and their partly fluorinated counterparts ( l -APFOE and l -SPFOE, respectively) into sodium chloride (NaCl)/water mixtures, separately. The pitch measurements were used to evaluate the helical twisting powers of each fluorinated/hydrogenated chiral surfactants. The results indicated that the twist structure of fluorocarbon chain provides higher helical twisting power with respect to the hydrocarbon chain. [ABSTRACT FROM AUTHOR]

High-speed laser imaging (HSLI) is the preferred technique to characterize the geometry of the plume in pressurized metered dose inhalers (pMDIs). However, current methods do not allow for simulation of inhalation airflow and do not use drug mass quantification to determine plume angles. To address these limitations, a Plume Induction Port Evaluator (PIPE) was designed to characterize the plume geometry based on mass deposition patterns. The method is easily adaptable to current pMDI characterization methodologies, uses similar calculations methods, and can be used under airflow. The effect of airflow and formulation on the plume geometry were evaluated using PIPE and HSLI. Deposition patterns in PIPE were highly reproducible and log-normal distributed. Mass Median Plume Angle (MMPA) was a new characterization parameter to describe the effective angle of the droplets deposited in the induction port. Plume angles determined by mass showed a significant decrease in size as ethanol increases which correlates to the decrease on vapor pressure in the formulation. Additionally, airflow significantly decreased the angle of the plumes when cascade impactor was operated under flow. PIPE is an alternative to laser-based characterization methods to evaluate the plume angle of pMDIs based on reliable drug quantification while simulating patient inhalation. [ABSTRACT FROM AUTHOR]

Copyright of Technical Transactions / Czasopismo Techniczne is the property of Sciendo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Loess-paleosol sequences (LPS) are sensitive terrestrial archives of past aeolian dynamics and paleoclimatic changes within the Quaternary. Grain size (GS) analysis is commonly used to interpret aeolian dynamics and climate influences on LPS, based on granulometric parameters such as specific GS classes, ratios of GS classes and statistical manipulation of GS data. However, the GS distribution of a loess sample is not solely a function of aeolian dynamics; rather complex polygenetic depositional and post-depositional processes must be taken into account. This study assesses the reliability of fixed GS ratios as proxies for past sedimentation dynamics using the case study of Remizovka in southeast Kazakhstan. Continuous sampling of the upper 8 m of the profile, which shows extremely weak pedogenic alteration and is therefore dominated by primary aeolian activity, indicates that fixed GS ratios do not adequately serve as proxies for loess sedimentation dynamics. We find through the calculation of single value parameters, that “true” variations within sensitive GS classes are masked by relative changes of the more frequent classes. Heatmap signatures provide the visualization of GS variability within LPS without significant data loss within the measured classes of a sample, or across all measured samples. We also examine the effect of two different commonly used laser diffraction devices on GS ratio calculation by duplicate measurements, the Beckman Coulter (LS13320) and a Malvern Mastersizer Hydro (MM2000), as well as the applicability and significance of the so-called “twin peak ratio” previously developed on samples from the same section. The LS13320 provides higher resolution results than the MM2000, nevertheless the GS ratios related to variations in the silt-sized fraction were comparable. However, we could not detect a twin peak within the coarse silt as detected in the original study using the same device. Our GS measurements differ from previous works at Remizovka in several instances, calling into question the interpretation of paleoclimatic implications using GS data alone. [ABSTRACT FROM AUTHOR]

Kinetic analysis by means of low-angle laser light scattering has been used for the investigation into active pharmaceutical ingredients solubility depending on the content of heavy isotope of hydrogen 1 2H (D) in water. Rate constants of active pharmaceutical ingredient solubility differ approximately by ~1.5 times for the two types of water with different deuterium/protium ratios, natural deionized high-ohmic water (D/H= 140 ppm) and deuterium-depleted water (D/H= 4 ppm). Results are to be utilized in order to control the quality of pharmaceutical substances with the purpose of dissolution quantitative evaluation, as well as with the aim of tackling the issue of new active pharmaceutical ingredients' low solubility while developing drugs. [ABSTRACT FROM AUTHOR]

Real-time measurements of Suspended Sediment mass Concentration ( SSC ) and Particle Size Distribution (PSD) are of prime importance for the investigation and management of fine-sediment related processes in surface water systems and hydraulic schemes. In a field study at the waterway of the hydropower plant (HPP) Fieschertal in the Swiss Alps, the real-time measurement performance of the following techniques and instruments were assessed based on measurements in the sediment seasons of the years 2013 and 2014: (1) turbidimetry, (2) single-frequency acoustic attenuation using a standard acoustic discharge measurement (ADM) installation, (3) laser diffraction (Laser In-Situ Scattering and Transmissometry, LISST), and (4) vibrating tube densimetry using a Coriolis Flow and Density Meter (CFDM). Reference SSC s were obtained from gravimetric analysis of 219 automatically pumped water samples. LISST additionally supplied PSD every minute. The median particle diameter, d 50 , was usually 15 µm and increased occasionally to 100 µm. The turbidimeter and the ADM underestimated the SSC when the transported particles were coarser than usual. Such temporary biases resulted from the poor correlation between d 50 and SSC at this study site. The SSC s from CFDM and LISST were not or less biased by PSD variations. Mainly due to angular and flaky particle shapes, SSC from LISST needed a correction by 79% on average. With the usually prevailing silt particles, an optical path length of 5 mm and no dilution, the SSC measurement range of LISST was limited to about 1.5 g/l. The CFDM allowed measuring higher SSC than the other investigated instruments (e.g. up to 13.5 g/l). With a periodic offset correction, its relative SSC measurement uncertainty was < 20% for SSC ≥ 1.5 g/l. To reliably measure a wide range of SSC with temporarily variable PSD, a combination of instruments is recommended: e.g. a standard LISST, a CFDM, and an automatic water sampler for gravimetric reference measurements. [ABSTRACT FROM AUTHOR]

A combination of two indirect methods to measure sediment flux is presented in this study to evaluate suspended sediment transport in a hydropower reservoir. The acoustic backscatter signal (ABS) from an Acoustic Doppler Current Profiler (ADCP) is therefore applied in pre-defined transects within the reservoir in combination with a Laser In-Situ Scattering Transmissometry – stream lined device (LISST-SL). The stationary LISST-SL derived suspended sediment concentration (SSC) measurements are used to calibrate the ABS. From the LISST-SL measurements a time series of SSC is obtained. This enables, in addition, a comprehensive data analysis to evaluate the influence of natural fluctuations of the SSC on the calculated sediment flux, which should be taken into account when assessing sediment transport. Furthermore SSC measurements are done with the LISST-SL close to the reservoir bed. In areas close to the bed no information regarding the ABS is available from the ADCP measurements due to the side-lobe interference. In various studies the information from the last three valid cells is used for extrapolation. However, as result of a comparison of the LISST-SL measurements with extrapolated SSC values from the ADCP measurements it can be seen that, especially in deep reservoirs, this method has to be adapted to the in-situ conditions. [ABSTRACT FROM AUTHOR]

The objective of this work is to demonstrate changes in properties and increase of biological activity of nicotinamide (NAM) substance for skin protectants activated by mechanical activation (MA). To assess the physical, chemical and biological properties of NAM were used biotesting by the Spirotox-method, direct and indirect optical methods (microscopy, laser diffraction), infrared spectroscopy, pH-metry. The results of the study showed an increase in biological activity, expressed in changes in the energy of activation of cell transition to the “dead cell” state on the example of biosensor Spirostomum ambiguum. Also we indicated an increase in the rate of the chemical process of dissolution of mechanoactivated molecular crystals of nicotinamide (NAM) expressed in the values of the first order rate constant. Mechanical activation at a high rate of NAM substance powder deformation has led to changes in physical, chemical and biological properties of the drug, which can be used in medicine to increase efficiency and reduce doses of pharmacotherapy.

In this study, we evaluated the fundamental physical behavior during droplet formation and flow from a rotary bell spray in the absence of an electrostatic field. The impact of a wide range of operating parameters of the rotary bell sprayer, such as flow rates, rotational speeds, and spatial positioning, on droplet sizes and size distributions using a three-dimensional (3-D) mapping was studied. The results showed that increasing the rotational speed caused the Sauter mean diameter of the droplets to decrease while increasing flow rate increased the droplet sizes. The rotational speed effect, however, was dominant compared to the effect of flow rate. An increase in droplet size radially away from the cup was noted in the vicinity of the cup, nevertheless, as the lateral distances from the cup and rotational speed were increased, the droplet sizes within the flow field became more uniform. This result is of importance for painting industries, which are looking for optimal target distances for uniform painting appearance. Furthermore, the theoretical formulation was validated with experimental data, which provides a wider range of applicability in terms of environment and parameters that could be tested. This work also provides an abundance of measurements, which can serve as a database for the validation of future droplet disintegration simulations.