Conventional Particle Size Research Articles

Effects of particle size reduction of meadow hay on feed intake, performance, and apparent total tract nutrient digestibility in dairy cows

ABSTRACT Forage-based diets are encouraged in organic dairy cattle production as this can increase the net human food supply, but their voluminous nature can limit dry matter intake (DMI) and performance. This study investigates the effects of a substantial particle size reduction of hay on dairy cows’ feed intake, performance, and body characteristics, as well as on apparent total tract digestibility (ATTD). Eighteen lactating Holstein cows were allocated to two balanced feeding groups. The control group received long stem hay with a conventional particle size (CON), the experimental group received chopped hay (RED). Both groups were supplemented with concentrates (3.6 kg/d, DM basis). After 14 adaptation days, data were collected for 20 consecutive days. A covariate period of 21 days preceded the experimental feeding period. Particles retained on the 19-, 8- and 4-mm screens and on the pan of the Penn State Particle Separator accounted for 21%, 20%, 20% and 39% of the RED hay. CON hay consisted of 72% large particles, followed by 8%, 7% and 13% retained on the other screens. Average DMI levels of cows in the CON group reached 20.8 kg/d, with a nonsignificant increase (+1.05 kg/d) in the RED group (p = 0.28). Intakes of both NFC (+0.65 kg/d, p = 0.01) and CP (+0.28 kg/d, p = 0.05) were significantly greater in the RED group, resulting in a slightly increased milk yield (+0.8 kg energy corrected milk/d) (p = 0.45), likely because the ATTD decreased significantly when feeding RED hay. No impact was observed on energy balance (103.7 vs 103.9%, p = 0.95), feed conversion efficiency (kg ECM/kg DMI), or N use efficiency. Overall, the results indicate increases in intake of NFC and CP in the RED group when feeding a hay-based (>83%, DM basis) diet, but also a decrease in nutrient digestibility, likely due to increased passage rate, potentially because of the high fraction of hay particles < 4 mm. In conclusion, hay-based rations with a lower proportion of fine particles should be tested to exploit the potential of particle size reduction in terms of improving hay use efficiency.

Agglomeration of particles stored in a box

Metallic nanoparticles are an essential part of advanced rocket fuels. Because of difficulties caused by hard ignition, incomplete reaction, and large size of combustion residues metallic particles with conventional particle sizes are unfavorable. However, the application of nanosized metallic particles does not show these disadvantages, in contrast, the application of nanosized metallic particles increases burning rates and reduces the two-phase specific impulse losses associated with solid combustion residues. On the other side, nanosized metallic particles are problematic, too. Nanoparticles, especially metallic ones, have a tendency to agglomerate. The formation of agglomerates leads to a reduction of the total surface of the particles and, therefore, to a reduction of the surface energy. This paper is limited to the process of agglomeration. As agglomeration is a random process, meaningful results are possible only using statistical methods. For this paper, a model with random selection of the particles based on Markow chains was applied. To evaluate the stability of the agglomerated product, the entropy was calculated. The results show that, with increasing agglomeration, the entropy increases exponentially. The thermodynamically better criterion is the free enthalpy; however, in lack of adequate materials data, this criterion could not be applied. Therefore, in general, the consideration presented in this paper are not specific for the addition of a specific metal.

The Role of Particle Size Distribution for Fluid Loss Materials on Formation of Filter-Cakes and Avoiding Formation Damage

Abstract Numerous studies have shown that careful particle size selection is the main parameter for reducing fluid loss when drilling permeable or fractured formations. The methods are generally built around either the D50 or D90 values of the particles in the fluid as a relative size to the pore openings of the formation to minimize fluid loss. A series of studies were conducted with the aim of assessing if analysis of fluid loss could be used to separate the formation of internal and external filter-cakes, thereby enabling a more accurate estimate of the permeabilities of the internal and external filter-cakes. It was concluded that conventional particle size methods were found to be adequate for designing a fluid for wellbore stabilization purposes. This led to higher solids invasion and a more impermeable internal filter-cake. However, for optimization of reservoir drilling fluids, a different particle size selection method was found to be more useful to prevent reservoir formation damage. This method involves selecting particles that are resistant towards shear-degradation and with a D90 particle size ⪞3/2 the pore size of the formation. By analyzing fluid loss regression data and correlating these with indicators of formation damage, such as disc mass and permeability change, it was found that a ratio defined as the relative plugging factor could provide insight into the extent of solids invasion into the formation and potential formation damage.

Proposal for an initial screening method for identifying microplastics in marine sediments

Marine debris, which is often called microplastics, is widespread in marine environments, particularly in sediments, and is recognized as an environmental hazard because it concentrates contaminants, forms biofilms, and sinks into marine sediments. In sediments, it may be ingested by benthos and have a negative impact on higher food chain levels. In this study, a new protocol was developed to identify microplastics in various sediment fractions. This protocol combined sieving and staining based on ordinal geotechnical/geological testing methods. The sieving process was derived from the conventional particle size distribution test, and nontoxic dyes were employed in the staining process. The protocol is safe and easy to perform as it merely involves the use of conventional geological/geotechnical testing equipment. The new protocol was successfully employed to stain and categorize different types and sizes of microplastic particles from contaminated sediments. This safe, easy-to-use, and efficient protocol can serve as the basis for a new alternative approach to study microplastics present in sediments, which can be performed using basic materials familiar to geotechnical/geological engineers.

Impact of isolation methods on the biophysical heterogeneity of single extracellular vesicles

Extracellular vesicles (EVs) have raised high expectations as a novel class of diagnostics and therapeutics. However, variabilities in EV isolation methods and the unresolved structural complexity of these biological-nanoparticles (sub-100 nm) necessitate rigorous biophysical characterization of single EVs. Here, using atomic force microscopy (AFM) in conjunction with direct stochastic optical reconstruction microscopy (dSTORM), micro-fluidic resistive pore sizing (MRPS), and multi-angle light scattering (MALS) techniques, we compared the size, structure and unique surface properties of breast cancer cell-derived small EVs (sEV) obtained using four different isolation methods. AFM and dSTORM particle size distributions showed coherent unimodal and bimodal particle size populations isolated via centrifugation and immune-affinity methods respectively. More importantly, AFM imaging revealed striking differences in sEV nanoscale morphology, surface nano-roughness, and relative abundance of non-vesicles among different isolation methods. Precipitation-based isolation method exhibited the highest particle counts, yet nanoscale imaging revealed the additional presence of aggregates and polymeric residues. Together, our findings demonstrate the significance of orthogonal label-free surface characteristics of single sEVs, not discernable via conventional particle sizing and counts alone. Quantifying key nanoscale structural characteristics of sEVs, collectively termed ‘EV-nano-metrics’ enhances the understanding of the complexity and heterogeneity of sEV isolates, with broad implications for EV-analyte based research and clinical use.

Enhancing the Mechanical Properties of Glass-Ionomer Dental Cements: A Review.

This paper reviews the strategies that have been reported in the literature to attempt to reinforce glass-ionomer dental cements, both conventional and resin-modified. These cements are widely used in current clinical practice, but their use is limited to regions where loading is not high. Reinforcement might extend these applications, particularly to the posterior dentition. A variety of strategies have been identified, including the use of fibres, nanoparticles, and larger particle additives. One problem revealed by the literature survey is the limited extent to which researchers have used International Standard test methods. This makes comparison of results very difficult. However, it does seem possible to draw conclusions from this substantial body of work and these are (1) that powders with conventional particle sizes do not reinforce glass-ionomer cements, (2) certain fibres and certain nanoparticles give distinct improvements in strength, and (3) in the case of the nanoparticles these improvements are associated with differences in the morphology of the cement matrix, in particular, a reduction in the porosity. Despite these improvements, none of the developments has yet been translated into clinical use.

Feeding forages with reduced particle size in a total mixed ration improves feed intake, total-tract digestibility, and performance of organic dairy cows

The optimal utilization of forages is crucial in cattle production, especially in organic dairy systems that encourage forage-based feeding with limited concentrate amounts. Reduction of the particle size of forages is known to improve feed intake and thus might be a viable option to help cows cope with less nutrient-dense feeds. The main aim of this study was to evaluate the effects of reducing forage particle size with a geometric mean of 52 mm (conventional particle size; CON) to 7 mm (reduced particle size; RED) in a high-forage diet (80% of dry matter) on dairy cows' sorting behavior, feed intake, chewing activity, and performance as well as on total-tract nutrient digestibility. Both diets (CON and RED) consisted of 43% grass hay, 37% clover-grass silage, and 20% concentrate and contained roughly 44% NDF, 15% CP, and 0.5% starch (dry matter basis). For CON, particle size was set by mixing all components for 20 min in a vertical feed mixer. The RED diet was treated the same, but before the mixer was filled, forages were chopped (theoretical length of cut = 0.5 cm) and the hay was hammer-milled (sieve size = 2 cm). Four primiparous and 16 multiparous mid-lactating dairy cows were assigned according to milk yield, body weight (BW), days in milk, and parity into 2 groups and fed 1 of the 2 diets for 34 d. The first 13 d were used for diet adaption, followed by data collection of nutrient intake, chewing activity, sorting behavior, milk production, and nutrient digestibility for the last 21 d of the experiment. Seven days before the start of the experiment, data on BW, dry matter intake (DMI), chewing activity, sorting behavior, and milk production were collected for use as covariates. Results showed that the RED diet improved DMI (+1.8 kg/d) and NDF intake (+0.46 kg/d) but decreased intake of physically effective NDF >8 (-3.25 kg/d). The RED-fed cows increased their intake of smaller particles (<19 mm), whereas CON-fed cows sorted for long particles (>19 mm). The RED cows reduced eating and ruminating time per kilogram of DMI by 4.8 and 1.9 min, respectively, suggesting lower mastication efforts. In addition, the RED diet significantly increased apparent total-tract digestibility of nutrients. As a consequence, RED cows' energy-corrected milk yield was higher (27.0 vs. 29.3 kg/d) without affecting milk solids, cow BW, or feed efficiency. In conclusion, the data support a reduction of forage particle size in high-forage diets as a measure to improve energy intake, performance, and hence forage utilization under these feeding conditions.

Using focused beam reflectance measurement (FBRM) to monitor aggregate structures formed in flocculated clay suspensions

The shear sensitivity of fragile, low-density aggregates formed in particle suspensions by polymer-bridging flocculation makes characterisation methods needing sampling or dilution problematic. Focused beam reflectance measurement (FBRM) probes can readily monitor such structures in real-time, but interpretation of resulting chord length data can be superficial, often missing detail within the distributions. However, the potential for deeper insights can’t be realised if flocculating with poor control of applied shear conditions (intensity and duration). In this study, continuous flocculation was achieved in a Couette mixing device with a vertical flow-through arrangement, acquiring operator-independent settling rate and FBRM chord data. The performance of a series of anionic flocculants (same charge density but different molecular weights) was investigated when applied to kaolin suspensions, with the introduction of 10 or 20% bentonite used to induce ‘bad’ flocculation responses. Size-density relationships in selected samples were determined separately by image analysis of free-settling aggregates.Following well controlled flocculation, distinct relationships between settling rate and mean volume-weighted chord length were attributed to variations in both substrate mineralogy and applied mixing intensity impacting on aggregate density. No such distinctions could be drawn from variations in flocculant molecular weight. Unweighted chord length distributions offered sensitivity to inefficiencies in fines capture and aggregate breakage under higher shear, which were both impacted by flocculant molecular weight. The unweighted chord counts <10 µm for the unflocculated clay slurries better anticipated dosage demand than conventional (volume-based) particle sizing, showing the potential of FBRM feed monitoring for flocculation control.

Application of TG-FTIR analysis to superfine pulverized coal

Thermogravimetric test combined with FTIR analysis is conducted to reveal the yield profile of gaseous species and functional groups, both for conventional and superfine pulverized coal (average particle size below or around 20 μm). Generally speaking, the yield of CO2 is less for superfine pulverized coal particle compared with conventional particle size. Since the content of carbonyl group is reduced, the amount of CO2 released during the pyrolysis is more for coal of lower rank (i.e. Neimenggu bituminous coal). CO yield of Neimenggu coal is greater than Shenhua coal, because more side chains and hydroxyl groups are owned by coal of lower rank. As CO group is likely to be linked to the same compound as CC group, the profile of CO group is similar to CC group. H2O evolution of superfine pulverized coal is higher than conventional particle size, for the impact of mechanochemical force for finer particle may be more prominent. With the decrease of the coal particle size, yield trend of CH4 gradually decreases, indicating that superfine pulverized coal is possibly engaged in NO reduction at the early stage of pyrolysis.

Comparative Evaluation of Bioactive Materials and Their Nano-Counterpart as Pulp Capping Agents in Dogs’ Teeth

Introduction: Direct pulp-capping is an alternative procedure to extraction or endodontic therapy, in which a medicament is placed directly over the exposed pulp to maintain pulp vitality and facilitate the formation of protective barrier. Aim of study: The purpose of this study was to evaluate and compare the histological response of dog’s pulp after direct pulp capping with 3 different materials; MTA, Bioactive glass, CEM and their nanoparticles, at 1 month and 3 month time intervals. Materials & Methods: A total of 112 teeth in 8 dogs were used for this study, where 96 teeth were pulp capped with the investigated materials and 16 teeth were serving as negative control. The 14 teeth of each dog were classified into 6 experimental groups and one control (2 teeth each) as follows: Group A: was capped with MTA, Group B: was capped with NMTA, Group C: was capped with CEM, Group D: was capped with NCEM, Group E: was capped with Bioactive glass, Group F: was capped with Nano Bioactive glass and Group G: unprepared tooth (negative control). Dogs were randomly divided into 2 groups (4 dogs each), relative to the observation periods tested, 1 month and 3 months for histomorphological evaluation of pulp response after direct pulp capping with tested materials. Results: Regarding the dentin bridge formation, both NMTA and NCEM groups induced thick dentin bridge with irregular dentin pattern in 1 and 3 months evaluation time period while MTA and CEM induced thinner dentin bridge with regular dentin pattern. BG and NBG groups showed the lowest mean dentin bridge thickness values with no tubular dentin pattern. About the inflammatory reaction of the dental pulp to materials with conventional particle size; MTA displayed the highest prevalence of no inflammation followed by CEM while BG showed the highest prevalence of moderate inflammation and the highest inflammatory cell counts. All nanomaterials showed the highest mean inflammatory cell counts at both evaluations time periods. Conclusion: MTA and CEM can be considered favorable materials for direct pulp capping, while BG and NBG produced the worst inflammatory cell reaction, dentin bridge thickness and quality. Nanoparticles although increased dentin bridge thickness, they also increased the inflammatory cell reaction.

Size distribution of wood particles for extruded particleboard production determined by sieve analysis and image analysis-based particle size measurement

Three wood particle types of different origin [knife ring flaker (KRF), hammer mill (HM), sawmill plant] for the manufacture of extruded particleboards were characterized by conventional sieve analysis and image analysis-based particle size measurement. Sieve analysis was performed following two different approaches (on-site, off-site). Image analysis-based measurement was done applying the so-called QICPIC apparatus from Sympatec GmbH (Clausthal-Zellerfeld, Germany). It was found that the size distributions of particles derived from timber production (sawdust) were different in comparison to those of KRF or HM manufacture.

Characterizing powder materials using keypoint-based computer vision methods

We applied the bag of visual words model for visual texture to a dataset of realistic powder micrograph images drawn from eight closely related particle size distributions. We found that image texture based powder classification performance saturates at 89±3% with 640 training images (80 images per class). This classification accuracy is comparable to classification using conventional segmentation-based particle size analysis. Furthermore, we found that particle size distributions obtained via watershed segmentation are generally not statistically equivalent to the ground truth particle size distributions, as quantified by the two-sample Kolmogorov-Smirnov test for distribution equivalence. We expect image texture classification methods to outperform particle size analysis for more challenging real-world powder classification tasks by capturing additional information about particle morphology and surface textures, which add complexity to the image segmentation task inherent in particle size distribution estimation.

Insights into Spray Development from Metered-Dose Inhalers Through Quantitative X-ray Radiography.

Typical methods to study pMDI sprays employ particle sizing or visible light diagnostics, which suffer in regions of high spray density. X-ray techniques can be applied to pharmaceutical sprays to obtain information unattainable by conventional particle sizing and light-based techniques. We present a technique for obtaining quantitative measurements of spray density in pMDI sprays. A monochromatic focused X-ray beam was used to perform quantitative radiography measurements in the near-nozzle region and plume of HFA-propelled sprays. Measurements were obtained with a temporal resolution of 0.184 ms and spatial resolution of 5 μm. Steady flow conditions were reached after around 30 ms for the formulations examined with the spray device used. Spray evolution was affected by the inclusion of ethanol in the formulation and unaffected by the inclusion of 0.1% drug by weight. Estimation of the nozzle exit density showed that vapour is likely to dominate the flow leaving the inhaler nozzle during steady flow. Quantitative measurements in pMDI sprays allow the determination of nozzle exit conditions that are difficult to obtain experimentally by other means. Measurements of these nozzle exit conditions can improve understanding of the atomization mechanisms responsible for pMDI spray droplet and particle formation.

Parametric study of reburning of nitrogen oxide for superfine pulverized coal

An experimental investigation of process parameters design by superfine pulverized coal reburning on NOx reduction is carried out in a one-dimensional bench-scale combustion system. Reburning effectiveness for initial levels ranging from 600 to 650ppm is evaluated. It is found that for Shenhua bituminous coal, NOx reduction performance of superfine pulverized coal owns its unique advantage, 50% higher than conventional particle size. Medium reburning fuel fraction (RF20∼RF25) and low oxygen concentration are recommended to be ensured in this experiment. The yield of HCN and CH4 along the furnace axis does not seem to be decisive on the effect of particle size, but is closely related to the effect of reburning fuel fraction. Both exhaust and in-flame measurements are reported in this paper to provide valuable experimental data for practical engineering applications.

Improving clay content measurement in oxidic and volcanic ash soils of Hawaii by increasing dispersant concentration and ultrasonic energy levels

Quantifying clay content is a fundamental step in predicting and managing soil behaviors such as nutrient and water retention. However, clay measurements are underestimated when using standard methods of dispersion in soils rich in oxides and volcanic ash-derived non-crystalline minerals. Increasing levels of the chemical dispersant and ultrasonic energy are two simple techniques found to increase dispersion and clay measurements in temperate soils, but their effects are less known for oxidic and volcanic ash soils. In this study we investigated the effects of increasing dispersion concentration and ultrasonic energy on clay measurements for a range of oxidic and volcanic ash soils from Hawaii. While doubling and tripling the standard sodium hexametaphosphate concentration of 0.441gL−1 did not increase estimates of clay content, increasing levels of ultrasonic energy up to 1600JmL−1 significantly increased measured clay content for all oxide and volcanic ash soils. The response to ultrasonication was dependent on soil carbon, oxide content, and surface charge, with more energy needed to disperse soils higher in carbon, oxides, and positive charge. Scanning electron microscopy revealed damage to the sand fraction in some soils when ultrasonicated, but the extent of this damage was viewed as negligible. Porous sand-sized particles resembling pumice grains were also observed in some soils, suggesting that conventional particle size analysis and clay interpretations may not adequately describe surface related behaviors.

Industrial applications of supercritical fluids: A review

High pressure technologies involving sub and supercritical fluids offer the possibility to obtain new products with special characteristics or to design new processes, which are environmentally friendly and sustainable. By using high pressure as a processing tool one can also avoid the legal limitations for solvent residues and restrictions on use of conventional solvents in chemical processes. Supercritical fluids are already applied in several processes developed to commercial scale in pharmaceutical, food and textile industries. Extraction of valuable compounds from plant materials and their “in situ” formulation in products with specific properties is one of the very promising applications of high pressure technology. Particle formation using supercritical fluids may overcome the drawbacks of conventional particle size reduction processes. Because of their unique thermo-dynamic and fluid-dynamic properties, dense gases can also be used for impregnation of solid particles, particle coating, foaming etc. Some biochemical and chemical reactions performed in supercritical fluids have already been implemented at industrial scale to obtain products with high added value, while the use of supercritical fluids as heat carriers is a newly emerging field. In our short overview we present some applications and future expected development in the field of sub and supercritical fluids.

A novel high-pressure precipitation tandem homogenization technology for drug nanocrystals production – a case study with ursodeoxycholic acid

To overcome the limitations of the conventional particle size reduction technologies, a novel combinative particle size reduction method for the effective production of homogeneous nanosuspensions was investigated. Ursodeoxycholic acid, a poorly soluble drug representative, was tried to prepare nanosuspension by homogenization technology and high-pressure precipitation tandem homogenization technology. It was shown that the combinative approach could significantly improve the particle size reduction effectiveness over conventional homogenization approach. The Box–Behnken design analysis for process optimization revealed that the acceptable UDCA-NS was obtained wherein the optimal values of A, B, C and D were 10%, 500 bar, 0.125 and 600 bar, respectively. SEM results demonstrated that no significant aggregation or crystals growth could be observed in the freeze-dried UDCA nanocrystals. The DSC and XRD results showed that UDCA remained in a crystalline state. Dissolution velocities of the freeze-dried UDCA-NS powder were distinctly superior compared to those of the crude powder and physical mixture. The high-pressure precipitation tandem homogenization technology can be a good choice for nanosuspension preparation of poorly soluble UDCA, due to high efficiency of particle size reduction.

Characterization and stability studies of a novel liposomal cyclosporin A prepared using the supercritical fluid method: comparison with the modified conventional Bangham method

A novel method to prepare cyclosporin A encapsulated liposomes was introduced using supercritical fluid of carbon dioxide (SCF-CO2) as an antisolvent. To investigate the strength of the newly developed SCF-CO2 method compared with the modified conventional Bangham method, particle size, zeta potential, and polydispersity index (PDI) of both liposomal formulations were characterized and compared. In addition, entrapment efficiency (EE) and drug loading (DL) characteristics were analyzed by reversed-phase high-performance liquid chromatography. Significantly larger particle size and PDI were revealed from the conventional method, while EE (%) and DL (%) did not exhibit any significant differences. The SCF-CO2 liposomes were found to be relatively smaller, multilamellar, and spherical with a smoother surface as determined by transmission electron microscopy. SCF-CO2 liposomes showed no significant differences in their particle size and PDI after more than 3 months, whereas conventional liposomes exhibited significant changes in their particle size. The initial yield (%), EE (%), and DL (%) of SCF-CO2 liposomes and conventional liposomes were 90.98 ± 2.94, 92.20 ± 1.36, 20.99 ± 0.84 and 90.72 ± 2.83, 90.24 ± 1.37, 20.47 ± 0.94, respectively, which changed after 14 weeks to 86.65 ± 0.30, 87.63 ± 0.72, 18.98 ± 0.22 and 75.04 ± 8.80, 84.59 ± 5.13, 15.94 ± 2.80, respectively. Therefore, the newly developed SCF-CO2 method could be a better alternative compared with the conventional method and may provide a promising approach for large-scale production of liposomes.

Wear properties of CrC–37WC–18M coatings deposited by HVOF and HVAF spraying processes

CrC–37WC–18M cermet coatings were deposited using new feedstock powders which seem to combine the properties of WC–CoCr and CrC–NiCr coatings. A conventional particle size CrC–37WC–18M powder was used as feedstock for the HVOF (high velocity oxygen fuel) thermal spraying process and a fine particle distribution was used as feedstock for the HVAF (high velocity air fuel) thermal spraying process. In order to characterize the morphology of the feedstock powders and deposited coatings SEM and X-ray diffraction were used. The microhardness of the coatings was also studied. The wear behavior of the coatings was evaluated by pin-on-disk and rubber wheel abrasion tests. The HVAF coating showed equal or even better wear resistance as compared to corresponding HVOF coatings.

In Situ Characterization of Spinel Nanoceramic Suspensions

In this study, an approach to characterize ceramic colloidal suspensions has been developed, based on vitrification of aqueous ceramic suspensions and microstructural characterization using cryogenic‐temperature scanning electron microscopy (cryo‐SEM), augmented by conventional rheological measurements. The flocculation phenomenon in as‐milled and aged Mg‐spinel (MgAl2O4) aqueous suspensions was characterized. A microstructure based on hard particle agglomerates separated by long‐chain deflocculant molecules was directly observed, and correlated to the rheological properties of the suspension. Several levels of flocculation were detected as a function of suspension preparation conditions. Although suspensions at solid‐loading levels appropriate for ceramic processing cannot be characterized using conventional particle size measurement techniques, cryo‐SEM can be used to measure characteristic sizes, and to distinguish between agglomerated and flocculated particles, opening a new approach for optimizing solid‐loading conditions for slip casting in terms of viscosity and green density.