Laser Diffractometer Research Articles

The Use of a Laser Diffractometer to Analyze the Particle Size Distribution of Selected Organic Soils

This study was conducted to verify the usefulness of the laser diffractometer method for determining the particle size distribution of selected organic soils from the Podkarpacie region in Poland. The soil selected for this research represented three main classification groups, namely, low-organic, medium-organic and high-organic soil, in accordance with the standard criterion. Particle size distribution was determined using two types of laser diffractometers: the Helos laser diffractometer manufactured by Sympatec GmbH (Clausthal-Zellerfeld, Germany) and the laser particle size analyzer Analysette 22 MicroTech plus manufactured by Fritsch GmbH (Idar-Oberstein, Germany). The standard mechanical and sedimentation methods, which are perfect for testing mineral soils, are not applicable to organic soils; therefore, a serious problem was found and examined. A reference method that could verify the test results obtained using the laser diffractometer methods was required. After analyzing the literature, the hydrometric (sedimentation) method was adopted as the reference method. Currently, there are no reliable and fully verified methods for testing soils with such a complex skeleton structure, and the resources, standards and guidelines concerning the issues discussed are extremely limited; therefore, new research methods are being sought to fill this gap, and this work is a step in this direction. The results of the conducted studies and analyses have shown that laser diffractometry methods can be useful for determining the particle size distribution of organic soils, but to a limited extent, depending mainly on the quantity of organic substances. The highest agreement was obtained by comparing the results of the sedimentation method with those obtained using the diffractometer analyzer Analysette 22 in the group of highly organic soils.

Aerosol Delivery Efficiency With High-Flow Nasal Cannula Therapy in Neonatal, Pediatric, and Adult Nasal Upper-Airway and Lung Models.

High-flow nasal cannula (HFNC) systems employ different methods to provide aerosol to patients. This study compared delivery efficiency, particle size, and regional deposition of aerosolized bronchodilators during HFNC in neonatal, pediatric, and adult upper-airway and lung models between a proximal aerosol adapter and distal aerosol circuit chamber. A filter was connected to the upper airway to a spontaneously breathing lung model. Albuterol was nebulized using the aerosol adapter and circuit at different clinical flow settings. The aerosol mass deposited in the upper airway and lung was quantified. Particle size was measured with a laser diffractometer. Regional deposition was assessed with a gamma camera at each nebulizer location and patient model with minimum flow settings. Inhaled lung doses ranged from 0.2-0.8% for neonates, 0.2-2.2% for the small child, and 0.5-5.2% for the adult models. Neonatal inhaled lung doses were not different between the aerosol circuit and adapter, but the aerosol circuit showed marginally greater lung doses in the pediatric and adult patient models. Impacted aerosols and condensation in the non-heated HFNC and aerosol delivery components contributed to the dispersion of coarse liquid droplets, high deposition (11-44%), and occlusion of the supine neonatal upper airway. In contrast, the upright pediatric and adult upper-airway models had minimal deposition (0.3-7.0%) and high fugitive losses (∼24%) from liquid droplets leaking out of the nose. The high impactive losses in the aerosol adapter (56%) were better contained than in the aerosol circuit, resulting in less cannula sputter (5% vs 22%), fewer fugitive losses (18% vs 24%), and smaller inhaled aerosols (5 µm vs 13 µm). The inhaled lung dose was low (1-5%) during HFNC. Approaches that streamline aerosol delivery are needed to provide safe and effective therapy to patients receiving aerosolized medications with this HFNC system.

Application of Digital Correlation-Spectral Analysis for Identification, Classifiaction and Separation of Plant Roots and Plant Root Tissues: Simple Low-Cost Alternatives for Laser Diffractometer Based 2D FFT Pattern Recognition Techniques

Application of Digital Correlation-Spectral Analysis for Identification, Classifiaction and Separation of Plant Roots and Plant Root Tissues: Simple Low-Cost Alternatives for Laser Diffractometer Based 2D FFT Pattern Recognition Techniques

Characterization of suspended particles at different glacial bays at Spitsbergen

Particle size distribution (PSD) and concentration of mineral-suspended sediment released from melting glaciers are important factors affecting the local marine ecosystem, e.g. affecting the light availability in water columns, thus changing underwater light climate for photosynthetic organisms. We examined the characteristics of various samples of natural mineral assemblages suspended in different glacial bays in Hornsund and Kongsfjord at Spitsbergen. The concentrations of the total mass of particles (TSM) in suspended sediment as well as particular organic matter (POM) and particular inorganic matter mass (PIM) together with mineralogical composition and particular size distribution (PSD) were determined.In this study, we investigated the PSD properties and variability in the front of different tidewater glaciers based, laser diffractometer measurements (LISST-100x), and XRD – techniques to obtain the mineralogical composition of the particles. The sampled sites are under the strong influence of freshwater discharge from the glacier. At each station, inorganic particulate matter contributed up to 98% to total suspended matter with the particle concentration of the particle reaches up to 111 mg/l with mean surface PSD slopes ranging from 3.24 to 3.85. The result provides valuable baseline information on the observed range of variability of the size of suspended particles due to glacial runoff and the presence of particles of different mineral origin in the glacial bays.

The use of a laser diffractometer to analyse the particle size distribution of selected organic soils

The use of a laser diffractometer to analyse the particle size distribution of selected organic soils

Suspended Particulate Matter Investigations by the Optical Method in the Franz-Victoria Trough, the Barents Sea

The article describes results of the suspended particulate matter during 80th cruise of the RV Akademik Mstislav Keldysh in the Franz-Victoria Through, northern Barents Sea. Two perpendicular transections were carried out by means of small-angle laser diffractometer LISST-Deep operating in the red range with a wavelength of 670 nm. Observed data consist 7 thousand volume concentration and particle size distributions (PSD) measurements. Weather conditions during expedition allowed to extend the transection to southern part of Nansen basin. The volume concentration of suspended matter varied up to 7.58 μl/l in the euphotic zone and layer and from 0.2 to 0.5 μl/l in the nepheloid layer. Paper demonstrates construction possibilities of the particle size distributions profiles by depth. Transection comparison with measurement results by the conductometric method on a Coulter Counter of the bathometric samples were carried out.

Fluorescence-enabled evaluation of nasal tract deposition and coverage of pharmaceutical formulations in a silicone nasal cast using an innovative spray device

IntroductionThe characterisation of nasal formulations is a critical point. However, there are still no recommendations or guidelines in terms of standard approaches for evaluating the formulation's nasal deposition and/or coverage profile. This study optimises a method for quantifying silicone nasal cast deposition and coverage of liquid formulations using different nasal devices. ObjectivesThe present work investigates the nasal deposition and coverage patterns of innovative nasal spray nozzles producing slow velocity soft mists, using a nasal cavity replica and a fluorescent dye. MethodsThe study of the deposition pattern of a fluorescent liquid formulation in a transparent nasal cast was carried out in both the presence and absence of a simulated inhalation flow. The extent of the deposition pattern was investigated using ImageJ and fluorescence in the nasal cast, quantified by fluorometric analysis. The particle size distribution and initial droplet velocity were determined using a laser diffractometer and a high-speed camera with a frame rate of 1000 fps. ResultsA uniform intranasal coverage was obtained with droplets of a volume median particle size (Dv50) between 15 and 25 µm in airflow between 10 and 30 L/min. In these conditions, aerosol formulations can be uniformly deposited in the vestibule and turbinate cavity nasal regions, with less than 10 % passing beyond the nasopharyngeal region. ConclusionThe method applied allowed for the determination of the coverage of the nasal cast in different regions using images analysis and fluorometric analysis. Droplet velocity is a critical parameter in the deposition in the nasal cavity. With standard swirl nozzles, many droplets are found on the surface of the nasal vestibule. Soft mist nozzles produce smaller droplets at a much lower initial velocity (<1 m/s), resulting in a more uniform coverage.

Размер и содержание органических частиц в копролитах Aporrectodea caliginosa и Lumbricus rubellus

Размер и содержание органических частиц в копролитах Aporrectodea caliginosa и Lumbricus rubellus

The Effect of Adjuvant Concentration on Changes of Spray Characteristics and Spraying Parameters for Selected Types of Nozzles

Abstract The paper presents the results of the research on the influence of the adjuvant concentration on the size of the drops produced by the spray nozzles of agricultural sprayers. For the tests, adjuvant Normaton with the composition of total nitrogen, amide nitrogen (N-NH2) and phosphorus pentoxide (P2O5) was used. The adjuvant was added to the water taken from the municipal water supply system of the city of Lublin. The tests were carried out for three concentrations, i.e. 75%, 100%, and 125% of the adjuvant concentration recommended by the manufacturer, and water without the adjuvant. The surface tension of water with adjuvant was examined for each nozzle. Then, the size of the obtained droplets was measured for each adjuvant concentration. Two types of nozzles were used for spraying, standard nozzle AP 120-03 and 6MSC injector nozzle, both with the same nozzle flow rate, but with a different design. The size of the droplets produced was measured on a HELOSVARIO laser diffractometer by Sympatec. The droplet measurement was performed at a pressure of 3 bar. The nozzle was placed 50 cm above the diffractometer laser light line. The droplet size was measured in three places of the sprayed liquid, i.e. in the position of the nozzle axis, 30 and 60 cm from the nozzle axis. It was shown that the addition of the adjuvant influenced the number of droplets produced in the indicated droplet size classes.

Aggregate and Particle Size Distribution of the Soil Sediment Eroded on Steep Artificial Slopes

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.

Fluorescent phenylthiazoles: Application as latent fingermark and their cytotoxicity against NOK-SI cell line

Abstract Fingerprints are unique to each individual who contributes to human identification in forensic cases. In this sense, the present work aimed to synthesize 1H-pyrazol-1-yl-4-phenylthiazoles and apply them as powder agents to reveal latent finger marks as an alternative and low cost related to powders found on the market. The compounds were characterized by infrared; fluorescence; 1H NMR; 13C NMR; laser diffractometer and SEM. In addition, cytotoxicity was also evaluated in oral keratinocytes showing high cell viability. The result of the hemolytic assay revealed that compound 2a does not present red cell cytotoxicity. The prepared powders were applied to fingermarks deposited on different surfaces providing quality visualization at level three so that human identification is possible.

Effect of heat curing on early strength of high-performance mortar containing ferronickel slag as cement replacement

High-performance mortar (HPM) is a new material in construction projects which requires a huge amount of cement on its production. As a consequence, the cost of this material will increase. This problem can be solved by utilizing alternative binders combined with the latest curing technology to obtain a low cost of HPM without loss of quality. This study aims to examine the effect of heat curing on the compressive strength of HPM containing FNS as cement replacement in early days (7 days). The FNS was ground using a ball mill to achieve a fineness similar or higher than cement. A low water-to-cement ratio of 0.35 was chosen in this research. The series of HPM mixtures containing FNS used in this study were 0%, 5%, 10%, 15%, 20% and 30%. Heat curing at 75 °C was used to assess the performance of the HPM compared to normal curing. The particle size distribution of binders was determined using a laser diffractometer. The results showed that the presence of FNS in the HPM had a positive effect on the compressive strength at 7 days after applying heat curing. The use of heat curing at 75 °C increased the strength of HPM at 7 days.

Filtration capacity of a gravel inlet system under low accumulation conditions

Filtration models were applied to a gravel inlet system to estimate attachment and/or detachment of particles onto collectors (gravel grain). Two methods were used to estimate total solidstrapping efficiency at the gravel inlet: mass concentration and particle count. The first method provided trapping estimate between 11% and 22% based on two averaging computations. The second method, particle count, showed that detachment of total solids occurred mostly with the clay size category and early duringrainfall events. Detachment reveals the quality of effluent and can be interpreted as particles being detached either from previous total solids deposit or not being retained by the collector. Based on a model by Rajagopalan and Tien, trapping ability of gravel inlet was expected to be relatively low (&lt;50%) for particles and aggregates smaller than 100 μm. Five rainfall events in 2002 were analyzed and showed that the first event had a retention capacity of 32% with a significant statistical difference between pairs of samples from “above” and “below” the gravel, based on a paired t-test. The following rainfall events had not seen any significant difference based on the same statistical test between the above and below water samples; however, the pattern of retention within pairs of samples showed that large filtration values were associated with incoming large solids concentrations, which, in turn, are related to rainfall bursts. The laser diffractometer technique allowed the particle count method to estimate number of particles retained or detached with respect to the gravel media. Particle count was obtained by direct measurement in the fine silt and clay size region and by extrapolation of measured data for large size in the silt-sand region including small particles and aggregates. Two rainfall events (August 3 and 21) showed important detachment based on particle counting method.

In situ Measurements of the Characteristics of Suspended Particles in the Barents Sea by the LISST-Deep Laser Diffractometer

The key indicators of marine sediment genesis are the particle size distribution (PSD) and volume concentration of suspended particulate matter (SPM). However, their study is not widespread in ship oceanology research. This paper reviews experience in using the LISST-Deep laser particle size analyzer for the study of marine SPM in situ. We present the first data on the volume concentration and PSD of SPM in the Barents Sea obtained during the 75th cruise of the RV Akademik Mstislav Keldysh in June 2019. We carried out an assessment of the adequacy of information display on the polydisperse system composition of the Barents Sea water body, which contains particles of a wide particle size spectrum of differing genesis and shape. This paper gives a regression and correlation analysis of LISST-Deep data with a Wet Labs turbidity meter and Multisizer 3 Coulter Counter, as well as the SPM mass concentration measured by the membrane filtration technique. All of them demonstrated reliable correlations between characteristics of SPM of the Barents Sea. Their correlation and determination coefficients varied from 0.6 to 0.8. The laser diffractometer produces more detailed vertical distributions of marine SPM parameters than does a turbidity meter, especially for euphotic zones. We found a significant correlation of LISST-Deep data with the concentration of dissolved oxygen, which increases for coarse–silty and sandy fractions (47.7–92.6 and 92.6–250 µm, respectively). Also, there is a correlation with SPM composition between parameters as organic carbon concentration and phytoplankton pigments. These correlations give some indirect indications of SPM composition from laser diffractometer measurements.

Changing of Particle Size and Pore Structures of Calcium Oxide during Calcinations of Industrial Eggshell Waste

Surface area and particle size are significant properties of a catalyst that determine the reaction rate of the heterogeneous catalyst. In this research, calcium oxide derived from industrial eggshell waste was synthesized by thermal decomposition method under air-atmosphere. The obtained eggshell waste was washed, dried, and ground to 420 μm followed by calcination of the ground eggshell in different conditions including calcination temperature (800 to 900 °C) and holding time (1 to 4 hours). Changes of pore structure and the median particle size diameter of the obtained calcium oxides were systematically investigated by various scientific instruments. Results from powder X-ray diffractometer (PXRD) indicated that the calcium oxide can be obtained after calcination at both 800 and at 900°C. Laser diffractometer shows that median particle size diameter of calcium oxide significantly decreased by about 76-95 % with increasing of both calcination temperature and holding time. Additionally, specific surface area of calcium oxides determined by N2 adsorption experiment at-195 °C shows that surface area of calcium oxide dramatically decreased (37-84 %) with increasing both calcination temperature from 800 to 900 °C and calcination time from 1 to 4 hours. These results indicated that both calcination temperature and time play an important role in the shrinkage of pores of calcium oxide. Higher calcination temperature and longer holding time induce more shrinkage of pore leading to smaller particle size diameter and lower surface area of the calcium oxide catalyst.

Method for the determination of preferential orientation of marine particles from laser diffraction measurements.

In situ laser diffractometry (LD) is increasingly used in oceanographic studies to estimate sediment transport, particle fluxes and to assess the concentration of marine phytoplankton. It enables an accurate characterization of the size distribution of suspended particles from the scattering signal produced by their interaction with a collimated laser beam. LD reliably reflects the sizes of suspensions dominated by nearly spherical particles; however, when complex particle morphologies dominate the suspension (e.g. phytoplankton) the resulting particle size distribution (PSD) may present significant variations attributed to different factors. In particular, the orientation of non-spherical particles - which abound in the sea - modifies LD measurements of PSDs. While this may be interpreted as a drawback for some studies (i.e. when precise measurement of the volume concentration is required), we propose that detailed analysis of this signal provides information on particle orientation. We use PDMS micropillars with prescribed elliptical cross-sections to experimentally determine the dependence between the spatial orientation of elongated particles and changes in the PSD measured with a LISST laser diffractometer. We show that LD can be used to adequately characterize the different dimensions of the non-spherical particles at specific orientations. Using this property, we describe and validate a method to infer the preferential orientation of particles in the sea. Our study opens new perspectives in the use of in-situ LD in ocean research.

Cystic fibrosis in the modern therapeutic era: Give the shower a thought!

Fifty-two meshes of e-flow rapid® were characterized for tobramycin delivery with a laser diffractometer after 6 months of home use by cystic fibrosis patients treated with various nebulized drugs. Three meshes were out of order and 30 considered to be defective for tobramycin delivery. The use of the specific mesh cleaning shower system permitted 14 defective meshes to be in the expected range of nebulized volume.

Effects of flow pattern, device and formulation on particle size distribution of nebulized aerosol

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.

A research pathway for the study of the delivery and disposition of nebulised antibiotics: an incremental approach from in vitro to large animal models

BackgroundNebulised antibiotics are frequently used for the prevention or treatment of ventilator-associated pneumonia. Many factors may influence pulmonary drug concentrations with inaccurate dosing schedules potentially leading to therapeutic failure and/or the emergence of antibiotic resistance. We describe a research pathway for studying the pharmacokinetics of a nebulised antibiotic during mechanical ventilation using in vitro methods and ovine models, using tobramycin as the study antibiotic.MethodsIn vitro studies using a laser diffractometer and a bacterial-viral filter were used to measure the effect of the type and size of tracheal tubes and antibiotic concentration on the particle size distribution of the tobramycin 400 mg (4 ml; 100 mg/ml) and 160 mg (4 ml, 40 mg/ml) aerosol and nebulised mass delivered. To compare the regional drug distribution in the lung of two routes (intravenous and nebulised) of drug administration of tobramycin 400 mg, technetium-99m-labelled tobramycin 400 mg with planar nuclear medicine imaging was used in a mechanically ventilated ovine model. To measure tobramycin concentrations by intravenous and nebulised tobramycin 400 mg (4 ml, 100 mg/ml) administration in the lung interstitial space (ISF) fluid and blood of mechanically ventilated sheep, the microdialysis technique was used over an 8-h duration.ResultsTobramycin 100 mg/ml achieved a higher lung dose (121.3 mg) compared to 40 mg/ml (41.3 mg) solution. The imaging study with labelled tobramycin indicated that nebulised tobramycin distributed more extensively into each lung zone of the mechanically ventilated sheep than intravenous administration. A higher lung ISF peak concentration of tobramycin was observed with nebulised tobramycin (40.8 mg/l) compared to intravenous route (19.0 mg/l).ConclusionsThe research methods appear promising to describe lung pharmacokinetics for formulations intended for nebulisation during mechanical ventilation. These methods need further validation in an experimental pneumonia model to be able to contribute toward optimising dosing regimens to inform clinical trials and/or clinical use.

Characterisation of 40 mg/ml and 100 mg/ml tobramycin formulations for aerosol therapy with adult mechanical ventilation

BackgroundPreservative-free tobramycin is commonly used as aerosolized therapy for ventilator associated pneumonia. The comparative delivery profile of the formulations of two different concentrations (100 mg/ml and 40 mg/ml) is unknown. This study aims to evaluate the aerosol characteristics of these tobramycin formulations in a simulated adult mechanical ventilation model. MethodsSimulated adult mechanical ventilation set up and optimal settings were used in the study. Inhaled mass study was performed using bacterial/viral filters at the tip of the tracheal tube and in the expiratory limb of circuit. Laser diffractometer was used for characterising particle size distribution. The physicochemical characteristics of the formulations were described and nebulization characteristics compared using two airways, an endotracheal tube (ET) and a tracheostomy tube (TT). For each type of tube, three internal tube diameters were studied, 7 mm, 8 mm and 9 mm. ResultsThe lung dose was significantly higher for 100 mg/ml solution (mean 121.3 mg vs 41.3 mg). Viscosity was different (2.11cp vs 1.58cp) for 100 mg/ml vs 40 mg/ml respectively but surface tension was similar. For tobramycin 100 mg/ml vs 40 mg/ml, the volume median diameter (2.02 vs 1.9 μm) was comparable. The fine particle fraction (98.5 vs 85.4%) was higher and geometric standard deviation (1.36 vs 1.62 μm) was significantly lower for 100 mg/ml concentration. Nebulization duration was longer for 100 mg/ml solution (16.9 vs 10.1 min). The inhaled dose percent was similar (30%) but the exhaled dose was higher for 100 mg/ml solution (18.9 vs 10.4%). The differences in results were non-significant for type of tube or size except for a small but statistically significant reduction in inhaled mass with TT compared to ET (0.06%). ConclusionAerosolized tobramycin 100 mg/ml solution delivered higher lung dose compared to tobramycin 40 mg/ml solution. Tracheal tube type or size did not influence the aerosol characteristics and delivery parameters.