Determination Of Size Distribution Research Articles

Comparison of laser diffractometry and pipetting methods for particle size determination: A pilot study on the implications of result discrepancies on soil classification

AbstractIn recent decades, the determination of particle size distribution (PSD) using the laser diffraction method (LDM) has become increasingly common, supplanting traditional sedimentation techniques. Advances in everything from sample preparation to software settings have been realized globally, whether through recommendations from laser diffraction (LD) manufacturers or through user experiences. These developments seek to enhance accuracy and diminish the uncertainties associated with new methodologies. Particularly in the determination of PSD using LDM on various LD instruments and in comparison with the sieve–pipette method (SPM), discrepancies in PSD frequently arise. This article aims to mitigate these discrepancies by predefining parameters, specifically through the adjustment of LD software settings and sample preparation (employing a uniform set of dispersed samples in potassium hydroxide) on two widely used LD instruments for soil measurements: Mastersizer 3000 and Analysette 22. Additionally, these samples were analyzed using the traditional SPM (ISO 11277, 1998), with the results from LDM and SPM subsequently compared. The paper also explores the impact, range of user options, and limitations of predefined software settings on both LD instruments. Eighty soil samples were analyzed for PSD, collected from arable land in the cadastral area of Hrušky, district of Břeclav (Czech Republic), in spring 2022, from depths of 0‐ to 10‐cm and 10‐ to 20‐cm. Significant differences in PSD were confirmed, although the trends of the grain size distribution curves were very similar to those of LDM. Results from the Mastersizer underestimated the clay fraction by an average of 17% compared to SPM, at the expense of the sand fraction, whereas the silt fraction was underestimated by a maximum of 4%. Conversely, Analysette 22 overestimated the silt fraction by an average of 37% at the expense of the sand fraction, confirming only a slight difference in the clay fraction: 3%. Moreover, the quantity of sample entering the dispersion unit was identified as a significant issue when comparing LD instruments, despite the obscuration value being nearly identical, that is, 20%–30%. Therefore, it was not possible to achieve the same or similar weight when introducing suspension into circulation. The robustness of the obtained results underscores the importance of understanding input parameters when interpreting results between different methods.

STUDY OF SILVER NANOPARTICLES BIOACCUMULATION IN CULTURED RED AND GREEN SEAWEED

The bioaccumulation of polyvinylpyrrolidone-coated silver nanoparticles (PVP-AgNPs) in Palmaria palmata and Ulva sp. seaweed was investigated by ICP-MS and SP-ICP-MS (determination of nanoparticles and size distribution after an enzymatic extraction). Seaweeds were exposed to 0.1 and 1.0 mg L-1 of PVP-AgNPs of small particle size (15 nm) for 28 days. They were cultured in 40-L seawater tanks and nanoparticles were mixed with growing media and the phytoplankton used for feeding. Bioaccumulation changed with the type of seaweed and was not proportional to the concentration. Palmaria palmata and Ulva sp. reached the maximum total Ag concentration at 14 and 21 days of exposure to 1.0 mg L-1, respectively. The Ag concentrations measured (until 0.79 ± 0.06 μg g-1 w.w.) were much smaller than those found in previous studies after short-term exposure (up to 48 h) under laboratory conditions, probably due to the presence of organic matter in the growing media. The maximum concentrations of AgNPs were achieved at 14 and 28 days for Palmaria palmata and Ulva sp., respectively, with most frequent sizes of approximately 20 nm. The size values measured by SP-ICP-MS agreed with TEM sizes in the enzymatic extracts. No changes were observed in the concentrations of most metals (Co, Cr, Cu, Mo, Ni, Rb and V) in exposed seaweed; only a decrease of Cd and Pb at the dose of 1 mg L-1 in Palmaria was observed. Studies simulating the real marine environment are important to estimate bioaccumulation and safety, which change depending on the type of seaweed and nanoparticle.

Determination of Size, Size Distribution, and Concentration of Nanoparticles Using ICP‐MS in the Context of SERS Substrates

ABSTRACTSurface enhanced Raman scattering (SERS) is a widely used vibrational spectroscopic technique employing metallic nanostructures to enhance an inherent Raman signal. This study aimed to develop a method for the characterization of SERS substrates in a single analysis by inductively coupled plasma mass spectrometry (ICP‐MS) equipped with the single particle module (spICP‐MS). For this development, the well‐known Lee‐Meisel protocol was selected as starting point to synthesize gold nanoparticles (AuNps) and silver nanoparticles (AgNps). A spICP‐MS method was successfully developed and gave the mean size, size distribution, and concentration of nanoparticles in only one single analysis. Reference techniques were used to confirm these results namely dynamic light scattering, transmission electron microscopy, and UV–Visible spectroscopy. Thanks to the ICP‐MS characterization, it was observed that AgNps synthesized by chemical reduction presented more variability than the AuNps. The dissolved elements concentration in the suspension was investigated. It appeared that reaction yields were close to 100% for the six syntheses. This analysis may be repeated over time to evaluate the suspension stability and monitor any potential degradation of Nps. To conclude, ICP‐MS is a powerful technique to characterize SERS substrates and could be an interesting alternative to other characterization techniques.

Determination of the particle size distribution of cube-shaped colloidal perovskite quantum dots from photoluminescence spectra: A combined theoretical-experimental approach.

A theoretical-experimental approach is proposed to convert the photoluminescence spectra of colloidal perovskite quantum dot ensembles into accurate estimates for their intrinsic particle size distribution functions. Two main problems were addressed and properly correlated: the size dependence of the first excitonic transition in a single cube-shaped quantum dot and the inhomogeneous broadening of the fluorescence line shape due to the size nonuniformity of the chemically prepared quantum dot suspension in addition to the single-dot homogeneous broadening. By applying the reported methodology to CsPbBr3 quantum dot samples belonging to the strong and intermediate confinement regimes, the calculated size distributions exhibited close agreement with those obtained from transmission electron microscopy, with precise estimates for the average particle size and standard deviation. Specifically for strongly confined ultrasmall CsPbBr3 quantum dots, the presented spectroscopic model for size distribution computation is based on a new analytical expression for the size-dependent bandgap, which was developed within the framework of the finite-depth square-well effective mass approximation accounting for band nonparabolicity effects. Such a quantum mechanical approach correctly predicts the expected transition to the intermediate confinement regime in sufficiently large quantum dots, which are traditionally described by the well-known bandgap equation in the infinite potential barrier limit with a spatially correlated electron-hole wavefunction and nonparabolic carrier effective masses. The proposed calculation scheme originates from general theoretical considerations so that it can be readily adapted to semiconductor quantum dots of many other systems, from all inorganic metal halides to hybrid perovskite materials, regardless of the adopted chemical synthesis route.

Determination of the Radon Progeny Activity Size Distribution in Laboratory Conditions

Knowledge of the active size distribution of radon daughters is one of the main parameters for determining the effective dose from inhalation of short-term radon decay products. However, this parameter is crucial for accurately determining an effective dose; there are currently very limited possibilities for determining it. This paper describes the laboratory validation of a method for determining the activity size distribution of radon decay products using the Dekati ELPI+ cascade impactor and the Graded Screen Array Diffusion Battery (GSA DB). Using nuclear track detectors placed on individual impaction plates of the cascade impactor, the equivalent equilibrium activity concentration of individual size classes can be determined in the range from 17 nm to 10 μm. A diffusion battery was used to detect smaller particles in the unattached fraction area. The presented method can further refine the knowledge of the activity size distribution of radon decay products in different types of workplace atmospheres. Workplaces with higher radon concentrations differ significantly in the size distribution of aerosol particles, radon activity concentration, and equilibrium equivalent activity concentration.

STUDY OF STEVIA ECAPSULATION FOR USING IN PROBIOTIC DELIVERY SYSTEMS

At the moment, incoming products, beverages, raw materials on the market must comply with the requirements of State standards and safety requirements. The question of nutritional value is growing every day, based on the fact that the constant use of healthy foods develops the body's resistance to various diseases. Such products are called useful or functional products. An equally urgent task for today's specialists is the development of a functional fermented milk product that contains a pleasant sweet taste from natural Stevia plant extract. Stevia rebaudiana Bertoni is a natural sweetener, which has many useful properties. For example, one of the first benefits in low-calorie content does not include fast carbohydrates. So, Stevia has less effect on blood sugar levels and does not increase insulin and is suitable for diabetics. In addition, Stevia extract can be used as prebiotic for co-encapsulation with probiotic microorganisms to enrich functional beverages. Purpose of this study is investigation of formulation parameters for reсeiving саpsules whiсh сreаte а strong bаrrier to penetrаtion of the encapsulated substаnсe to the externаl environment; the саpsules providing more effiсient mаnifestаtion of а сomplex of biologiсаl, phаrmасologiсаl, preventive or mediсinаl properties of bаgged substаnсe. Development of cаpsules of the long term of storаge in whiсh the асtive loaded mаteriаl is proteсted by аn envelope аnd саn preserve activity in vаrious pH environments became the most perspective. Ionic gelation method through extrusion represents a simple encapsulation technique that does not require organic solvents, making it suitable for both hydrophobic or hydrophilic compounds. Stevia extract -loaded Alginate-Chitosan particles with improved physicochemical properties with a process yield of 88-89% were obtained. The release kinetics of active agent was monitored using UV-vis spectroscopy and showed a slow release within 24 hours. Thus, the slow kinetics of the release of the agent demonstrates the effectiveness of the methodology of encapsulation based on the ionic gelation and hardening of shell. Сreаtion of саpsules with the ingredients enсаpsulаted inside, hаving thermostаble properties, resistаnсe to influenсe of асidiс environments аnd enzymes, meсhаniсаl аnd osmotiс resistаnсe to influenсe of externаl physiсаl аnd сhemiсаl fасtors, suсh аs meсhаniсаl effeсt, temperаture inсreаse, сhаnge of pressure, аnd аlso inсreаse in proteсtion of bаgged substаnсes remains as an actual problem at present time. The morphology, average diameters of wet and dry microcapsule were determined by optical microscopy using Olympus Soft Imaging Solutions GmbH, version E_LCmicro_09Okt2009. Twenty microparticles were randomly selected from triplicate batches to determine size distribution. The compositions of microcapsules for analysis on a scanning electron microscope were applied to a highly conductive graphite tape. SEM equipment was used to determine the pore size on the surface of the microparticles. Studies results showed that sizes of microcapsules were 720-830 µm, and color was determined by color of loaded agent. Microencapsulation allows not only protect active agent from aggressive environment, prolong activity, but also can be used for development product with useful properties for human health. Funding: This research is funded by the Science Committee of the Ministry of Science and Higher Education of the Republic of Kazakhstan (Grant No. AP19679879).

Two deep learning methods in comparison to characterize droplet sizes in emulsification flow processes

For reliable supervision in multiphase processes, the droplet size represents a critical quality attribute and needs to be monitored. A promising approach is the use of smart image flow sensors since optical measurement is the most commonly used technique for droplet size distribution determination. For this, two different AI-based object detection methods, Mask RCNN and YOLOv4, are compared regarding their accuracy and their applicability to an emulsification flow process. Iterative optimization steps, including data diversification and adaption of training parameters, enable the models to achieve robust detection performance across varying image qualities and compositions. YOLOv4 shows better detection performances and more accurate results which leads to a wider application window than Mask RCNN in determining droplet sizes in emulsification processes. The final droplet detection model YOLOv4 with Hough Circle (HC) for feature extraction determines reliable droplet sizes across diverse datasets of liquid-liquid flow systems (disperse phase content 1–15 vol.-%, droplet size range 5–150 μm). Evaluating the adjustment of Confidence Scores (CS) ensures statistical representation of even smaller droplets. The droplet detection performance of the final YOLOv4 model is compared with a manual image processing method to validate the model in general as well as its accuracy and reliability. Since YOLOv4 in combination with Hough Circle (HC) shows an accurate and robust detection and size determination, it is applicable for online monitoring and characterization of various liquid-liquid flow processes.Graphical abstract

Removal of a model reactive azo dye from aqueous solution by a bioadsorbent in batch and fixed-bed column modes: Application of the developed technology to a textile wastewater

Sugarcane bagasse (SB) was used to produce a new bioadsorbent (STEA), drawing on circular economy concepts. STEA was synthesized using a two-step one-pot reaction, employing epichlorohydrin and triethylamine in the presence of N,N-dimethylformamide, without the use of a petroleum-based catalyst. The structure and surface of STEA were characterized by elemental C, H, N, and Cl analysis, X-ray diffraction, infrared spectroscopy, 13C solid-state nuclear magnetic resonance spectroscopy, thermogravimetric analysis, specific surface area and pore size distribution determination, and point of zero charge measurement. Batch adsorption and desorption tests were performed with the model dye Remazol Golden Yellow (RGY) RNL, a reactive anionic azo dye widely used in textile industry, to evaluate the potential reuse and application of STEA in a fixed-bed column for wastewater treatment. For batch adsorption, the best dose and agitation speed were 0.2 g L−1 and 50 rpm, respectively. STEA effectively removed RGY over a wide range of pH (2.00–10.00). The equilibrium time, maximum adsorption capacity (Qmax), and desorption efficiency (Edes) were 720 min, 369 mg g−1 (0.71 mmol g−1), and 49.5 %, respectively. The fixed-bed column fed with a spiked aqueous RGY solution could be operated for 415 min, with Qmax of 422 mg g−1 (0.81 mmol g−1) and Edes of 58.9 %. Batch and continuous experiments using real textile industry wastewater containing reactive azo dyes showed high color removal efficiency by STEA, with no interference of other compounds present in wastewater on adsorption of the reactive azo dyes (overshooting effect). The technology was validated in a relevant environment and achieved technology readiness level 5, showing potential to be upscaled. Therefore, STEA proved to be an efficient bio-based technology for application in tertiary treatment of real textile plant wastewater to remove reactive anionic azo dyes.

Influence of dry density and wetting–drying cycles on the soil–water retention curve of compacted loess: experimental data and modeling

In this paper, the EC-5 water sensor and the MPS-6 water potential sensor were used to measure water content and suction, respectively, to investigate the evolution of soil–water retention properties of compacted loess samples prepared at different dry densities and subjected to different numbers of wetting–drying cycles. The water retention data were integrated with a detailed microstructural investigation, including morphological analysis (by scanning electron microscopy) and pore size distribution determination (by nuclear magnetic resonance). The microstructural information obtained shed light on the double porosity nature of compacted loess, allowing the identification of the effects of compaction dry density and wetting–drying cycles at both intra- and inter-aggregate levels. The information obtained at the microstructural scale was used to provide a solid physical basis for the development of a simplified version of the water retention model presented in Della Vecchia et al. (Int J Numer Anal Meth Geomech 39: 702–723, 2015). The model, adapted for engineering application to compacted loess, requires only five parameters to capture the water retention properties of samples characterized by different compaction dry densities and subjected to different numbers of wetting–drying cycles. The comparison between numerical simulations and experimental results, both original and from the literature, shows that only one set of parameters is needed to reproduce the effects of dry density variation, while the variation of only one parameter allows the reproduction of the effects of wetting and drying cycles. With respect to the approaches presented in the literature, where ad hoc calibrations are often used to fit density and wetting–drying cycle effects, the model presented here shows a good compromise between simplicity and predictive capabilities, making it suitable for practical engineering applications.

Careful choice of carbonyl-containing cmps, and optimisation of Buchwald-Hartwig crosscoupling reaction conditions

In this study, new nitrogen-rich conjugated microporous polymers were synthesized using the Buchwald-Hartwig cross-coupling reaction. The synthesized polymers were characterized using various methods, including X-ray diffraction (XRD), ultraviolet-visible-near-infrared (UV-Vis-NIR) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, Brunauer-Emmett-Teller (BET) surface area analysis, and pore size distribution (PSD) determination using non-local density functional theory (NLDFT). The results provide important information about the structure and properties of synthesized materials, which contributes to a deeper understanding of their characteristics. The obtained characteristics of the material allow us to judge the quality and purity of the obtained polymers, which is important for further research, as well as serve as a basis for the development of new synthesis methods or improvement of existing technologies.

Technical note: Optimization of the preparation of cascade impactors collection substrates for airborne metallic ultrafine particle sampling

The characterization of workers’ exposure to airborne metallic ultrafine particles (UFP) has been an increasing issue because of their effects on health, and as many activities are potentially concerned such as welding, oxy-cutting or 3D printing. Determining the particle size distribution of such an aerosol provides a real contribution to the understanding of UFP exposures and associated health effects, as it is directly related to their penetration in the respiratory tract. In this context, it is proposed to optimize the preparation of collection substrates of cascade impactors of airborne metallic UFP. The experimental results confirm that the collection substrates have to be prepared beforehand by coating them with a high-vacuum-resistant silicone grease. The results highlight that this grease has to be preliminarily dissolved in a heptane-based solution with a mass ratio grease-solvent of 7.5%, and then deposited on the substrate with a target height of 9 μm. Applying this protocol ensures a reproducible and representative determination of the particle size distribution, allowing the phenomena of particle bouncing and reentrainment to be significantly reduced. It is also shown that coated collection substrates remain stable for several months in terms of mass, and that the samples collected remain stable during transport thanks to the improvement of particle cohesion on the coated membrane.

Pseudo-Eulerian model formulation for the determination of breakage frequency and daughter size distribution: Single droplet breakup experiments in turbulent flow

The study of breakage of single oil droplet in a turbulent flow is experimentally performed by means of direct visualization using high-speed imaging. A comparison of two different approaches for estimation of the breakage frequency is presented using the same set of experimental data. The first approach, estimates the breakage frequency based on the estimation of the averaged breakage time and breakage probability calculation based on single oil breakage experiments. The second approach consists in combining and superposing the different measurements into one population of droplets, to investigate the evolution of the size distribution of droplets emulating a pseudo-Eulerian representation. Using this approach, the breakage frequency can be estimated by following the evolution of the number of droplets of a particular size. We found that the pseudo-Eulerian approach is more accurate for construction of closure model for the implementation of population balance equation.

Improved stability and antibacterial activity of cinnamaldehyde emulsion co-stabilized by cyclodextrin glycosyltransferase-catalyzed starch products and Tween 80

Cinnamaldehyde, a yellowish essential oil, has potential applications because of its antibacterial ability but is limited by its instability. In this study, we prepared the microencapsulated cinnamaldehyde emulsion co-stabilized by cyclodextrin glycosyltransferase-catalyzed (CGTase-catalyzed) starch products and Tween 80. Microscopic structure analysis by transmission electron microscopy, inverted fluorescence microscopy, and size distribution determination revealed that additional CGTase-catalyzed starch products could increase their homogeneity and decrease their particle sizes by 67.8%. Fluorescence spectra analysis showed the interactions between cinnamaldehyde and the wall materials with a decrease of 29.2% in fluorescence intensity. The cinnamaldehyde emulsion had good temperature, ionic strength, pH, and storage stability. Time-kill curve and inhibition zone showed increased antibacterial activity. Mechanism analysis by thermal gravimetric analysis and differential scanning calorimetry showed that the emulsion had a dual structure of gel network and cyclodextrin inclusion, contributing to its stability. This study could give new insights into the cinnamaldehyde emulsion and provide a good guidance for its application.

A Novel Frontier in the Geographic Distribution of the Japanese Sea Cucumber Apostichopus japonicus (Selenka, 1867) (Stichopodidae: Holothuroidea) in the World

The natural distribution of the Japanese sea cucumber (Apostichopus japonicus Selenka, 1867), a sea cucumber species, is characterized by the Northwest Pacific. Long-term monitoring studies from 2020 to 2024 document a significant deviation from the known natural distribution of A. japonicus and its ability to extensively colonize the Gulf of Izmit, the easternmost part of the Sea of Marmara. This record is also the first documentation of the species from the Mediterranean Sea. Population data extracted from 67 samples allowed the determination of size and weight distribution, length-weight relationship, and condition factor. The study delves into the implications for fisheries management by evaluating the species’ dispersion beyond its natural range and its adaptation, shedding light on potential threats from illegal hookah diving fisheries. While its presence offers potential economic benefits through fishing income, its emergence as an invasive species can pose critical ecological risks to the receiving ecosystem.

Pengaruh Jenis Cairan, Jenis Batang, dan Panjang Batang pada Penentuan Distribusi Ukuran Partikel Bubuk Kaca Menggunakan Buoyancy Weighing-Bar Method (BWM)

Particle size distribution is one of the important physical parameters in industry. A new method has been developed, the buoyancy weighing-bar method to determine the particle size distribution. This study examines the application of the buoyancy weighing-bar method for the determination of the particle size distribution of glass powder. Measurements were made by varying the type of liquid, the type of rod, and the size of the rod length. From this study, it was obtained that the best condition in determining the particle size distribution of glass powder is using aluminum rods with a length of 210 mm in 96% ethanol. The results of determining the particle size distribution of glass powder by using the buoyancy weighing-bar method at the best conditions are comparable to the results of determining the particle size distribution obtained using the settling balance method.

Molecular size distribution in pentavalent (A, C, Y, W, X) meningococcal polysaccharide conjugate vaccine by HPSEC-UV-MALS-RI method- a conceivable stability indicating parameter

Molecular size distribution (MSD) of polysaccharides serves as a key parameter that directly correlates to the immunogenicity of vaccine. MSD at meningococcal polysaccharide (A, C, Y and W) or conjugate bulk level is well established under detailed pharmacopeial and WHO guidelines. We report here, a newly developed method for determination of molecular size distribution of pentavalent Meningococcal conjugate vaccine comprising of A, C, Y, W and X (MenFive). Although serogroup specific molecular size could not be estimated here; lot to lot consistency monitoring, molecular aggregates distribution in final lot, are key takeaways of this method. Determination of MSD in pentavalent fill finished product was quite challenging. Various columns/detectors combination, buffers, physico-chemical conditions (temperature, 2–8 °C, 25 °C, 40 °C and 60 °C; flow rate, 0.3 mL to 0.8 mL), liquid/lyophilized formulations, were explored. Polymer-based packed columns were explored for estimation for MSD by aqueous size exclusion chromatography, using combinations of- Shodex OHPAK SB 807 HQ, Shodex OHPAK SB 806 HQ, G6000 PWXL, coupled with guard Shodex OHPAK SB-G-6B. MenFive showed heterogenous distribution of molecules ranging from 200 to 19000 kDa, indicating its complex nature. However, 1000–8000 kDa was dominant range, comprising of ≥ 50 % distribution of molecules, in both liquid as well as lyophilized formulations, with average molecular weight around 6000–6500 kDa. The molar mass distribution after slicing would provide an insight to the conformation of molecules through its presentation as HMW, LMW, aggregates and subsequently, the presence of dominant population of molecules of a particular molecular weight and its total contribution in the sample.

Humic Polyelectrolytes Facilitate Rapid Microwave Synthesis of Silver Nanoparticles Suitable for Wound-Healing Applications.

This article describes the one-pot microwave synthesis of silver nanoparticles (AgNPs) assisted with natural polyelectrolytes-humic substances (HS). The humic polyelectrolytes served both as chemical reductants for silver ions and as end-capping agents for AgNPs. Three commercially available sodium humates extracted from lignites and leonardite and one sodium fulvate isolated from natural brown water seeped through peat deposits were used in this study. The dynamics of the growth rate of AgNPs was characterised by UV-VIS spectroscopy by measuring the intensity of surface plasmon resonance at 420 nm. Transmission electron microscopy was used to characterise the size and morphology of AgNPs. Dynamic light scattering was used to determine size distributions of the synthesised AgNPs in the solutions. It was established that both conventional and microwave syntheses assisted with the coal humates produced small-size AgNPs in the range from 4 to 14 nm, with the maximum share of particles with sizes of (6 ± 2) nm by TEM estimates. The peat fulvate yielded much larger NPs with sizes from 10 to 50 nm by TEM estimates. DLS measurements revealed multimodal distributions of AgNPs stabilised with HS, which included both single NPs with the sizes from 5 to 15 nm, as well as their dominating aggregates with sizes from 20 to 200 nm and a smaller portion of extra-large aggregates up to 1000 nm. The given aggregates were loosely bound by humic polyelectrolyte, which prevented the coalescence of AgNPs into larger particles, as can be seen in the TEM images. The significant acceleration in the reaction time-a factor of 60 to 70-was achieved with the use of MW irradiation: from 240 min down to 210-240 s. The coal humate stabilised AgNPs showed antimicrobial properties in relation to S. aureus. A conclusion was made regarding the substantial advantages of microwave synthesis in the context of time and scaling up for the large-scale production of AgNP-HS preparations with antimicrobial properties suitable for external wound-healing applications.

Determination of Particle Size Distribution: Comparison of Standard Hydrometer Method and Laser Diffraction Analysis for Use in Forestry

Laser diffraction analysis is an alternative to standard sedimentation methods designed to determine particle size distribution. In this article, five samples from the forested part of the floodplain of the Svitava River in the Czech Republic were analyzed. Laser diffraction analysis and sedimentation hydrometer method were performed for each sample. The samples were divided according to soil classification into two groups depending on their classification–group A and group B. The results of laser diffraction analysis and hydrometer method were compared. Correlation relationships between both methods were established, and values were recalculated from laser diffraction analysis to the hydrometer method according to correlation equations. The article is a part of the methodology under preparation, which will include the most common soil types in the Czech Republic. This methodology focuses on the use of laser diffraction for the establishment of structures in forest environments using the regional specific standards for particle size distribution determination.

Investigation of olfactory perception by a putative adsorption process of sotolone and abhexone on human olfactory receptor OR8D1: Statistical physics modeling and molecular docking

In the present paper, a double layer advanced model was used to investigate the adsorption process putatively involved in the olfactory perception of sotolone and abhexone molecules on the human olfactory receptor OR8D1. The number of adsorbed molecules or the fraction of adsorbed molecule per site, n, informed that the two odorants molecules are docked on OR8D1 binding sites with mixed parallel and nonparallel anchorages. Furthermore, the estimated molar adsorption energy (−ΔE1 and −ΔE2) were inferior to 40 kJ/mol for the two adsorption systems, which confirmed the physical nature and the exothermic character of the adsorption process. In addition, stereographic characterizations of the receptor sites surface were carried out through the determination of the receptor site size distribution (RSDs) via Kelvin equation, which spread out from 0.05 to 1.5 nm. The adsorption energy distributions (AEDs) via Polayni equation show an adsorption band spectrum localized between 17 kJ/mol and 22.5 kJ/mol for sotolone and abhexone molecules respectively. A molecular docking calculation was performed. The results indicate that the binding affinities are belonging to the spectrum of the energy band of the molecules sotolone and abhexone, with values 19.66 kJ/mol and 19.24 kJ/mol.

DETERMINING ROCK FRAGMENT SIZE DISTRIBUTION USING A CONVOLUTIONAL NEURAL NETWORK

Fast and relatively accurate determination of the fragment size distribution of a muck-pile is still a challenge in mining operations and the existing measurement methods are inefficient. In this research, a new algorithm to determine fragment size distribution due to blasting was presented, using the image processing technique. In the newly proposed approach, delineating of the fragmented rock particles, as the main core of processing, was carried out, using a convolutional neural network. Two networks were defined and trained by 150 laboratory and 150 field data images. Also, 30 laboratory and 30 field data images were applied to carry out the validation visually, and by using F1-scores. For the two laboratory and field networks and results obtained by Split-Desktop software automatic edge detection on the same images, the F1-scores are equal to (0.98, 0.74) and (0.99, 0.85) respectively. Also, for determination of fragment size distribution by laboratory data network and Split-Desktop software automatic edge detection on the same images, the Root Mean Square Error (RMSE) for F30 and F80 are equal to (0.36, 1.20) and (0.31, 1.24) respectively. These indicate better performance of the proposed approach for both rock edge detection and fragment size distribution over Split-Desktop software automatic edge detection.