Particle Size Range Research Articles

Application of Response Surface Methodology on the Optimization of Chromite Recovery from the South African Middle Group Chromite Seams

The aim of this study was to optimize the recovery of chromite from the chrome plant tailings of the South African Middle Group chromite seams using a Wilfley shaking table. The optimization process employed the response surface methodology in conjunction with the central composite design. The independent variables considered in the investigation included the tilt angle (°), sample feed rate (g/min), table vibration (Hz), water flow rate (L/H), and particle size range (µm). On the other hand, the recovery (%), grade (% Cr2O3), Cr/Fe ratio, and separation efficiency (SE) (%) were determined as the response variables. Based on the characterization results, the sample was identified as a low-grade chromite containing 19.86% Cr2O3 and 18.12% Fe2O3 with a Cr/Fe ratio of 1.07. The bulk gangue material was well-liberated and rich in MgO (10.45%), Al2O3 (12.10%), and SiO2 (33.70%). The particle size distribution of the sample was 80% passing 106 µm. The optimal values for recovery, grade, Cr/Fe ratio and SE were found to be 71.59%, 36.97% Cr2O3, 1.52 and 30% respectively. The corresponding operating conditions were a tilt angle of 5.88°, a sample feed rate of 175 g/min, a table vibration of 44.5 Hz, a water flow rate of 366.16 L/H, and a particle size range of − 106 + 53 µm.Graphical

Pollution characteristics, source apportionment and absorption spectra of size-resolved PAHs in atmospheric particles in a cold megacity of China

Polycyclic aromatic hydrocarbons (PAHs) have the capability for solar radiation absorption related to climate forcing. Herein, pollution characteristics and absorption spectra of size-resolved PAHs in atmospheric particles in a cold megacity were comprehensively investigated. The mean concentrations of Σ18PAHs in all the 11 particle size ranges were 3.95 ± 4.77 × 104 pg/m3 and 2.17 ± 1.54 × 103 pg/m3 in heating period (HP) and non-heating period (NHP), respectively. Except for most PAHs with 2 and 3 benzene rings in NHP, most other PAHs showed a unimodal distribution pattern with the peak at 0.56–1.0 µm in both periods, which was caused by PAH emission sources. The PAH-related climate forcing was mainly caused by the solar radiation absorptions at ∼325 (∼330) nm and ∼365 nm. In general, the absorption intensities were higher in HP than NHP. The absorption intensity in the particle size range of 0.56–1.0 µm was the highest, and benzo[e]pyrene was the dominant contributor. In colder periods in HP, higher PAH concentrations caused more intensive PAH-related climate forcing. This study provided new insights for pollution characteristics and absorption spectra of size-resolved PAHs in atmospheric particles, which will be useful for better understanding PAH-related climate forcing.

Highly bioactive hydroxyapatite coating made by flame spray technique

This research involves fabrication and characterization of flame sprayed hydroxyapatite (HA) coatings on 316 stainless steel substrates where the desirable structure with high porosity can be obtained. Nano-sized HA powder was synthesized and calcined at 600 °C. The subsequent powder was used as feedstock powder for flame spray technique (FS). In-flight particles of HA were spherical with the range of particle size between 3–37 µm. The average coating thickness was 128 µm and the crystalline phases were a mixture of HA and tricalcium phosphate (TCP). Simulated body fluid (SBF) test showed that HA layer was formed after 7 days. Highly bioactive properties were due to high surface area from rough coating and porous structure, which would be beneficial from the flame spray technique. The coating is promising for applications in biomedical field.

Study on the Influence of Particle Size Distribution on the Separation of Pyrite from Coal Gangue by Jigging

The presence of pyrite poses a significant impediment to the comprehensive utilization of coal gangue, which is a prevalent solid waste in industrial production. However, the current efficacy of jig separation for pyrite in fine-grade coal gangue remains unsatisfactory. To investigate the influence of particle size distribution on the jig separation of pyrite in fine-grade coal gangue, the raw material was crushed to less than 2 mm using a jaw crusher and subsequently sieved to obtain its particle size distribution curve. Upon fitting the curve, it was observed that it tends towards the Rosin-Rammler (RRSB) and Fuller distributions. Leveraging these two-parameter distribution curves, adjustments were made to determine the mass within each particle size range before conducting thorough mixing followed by jig separation. The results indicate that for fine-grade gangue particles smaller than 2 mm, the RRSB distribution with a uniformity coefficient of n = 0.85 exhibits the most effective separation, although it is comparable to the separation achieved using the size distribution of raw ore. On the other hand, employing the Fuller distribution with modulus of distribution q = 1.5 yields superior separation performance. In comparison to the raw ore, the concentrate shows an increase in sulfur (S) and iron (Fe) content by factors of 3.4 and 2.4, respectively. Furthermore, compared to the RRSB distribution, there is an increase in S and Fe content by 1.91% and 2.30%, respectively; the contents of S and Fe in tailings is 0.71% and 2.72%, which can be directly used as raw materials for coating materials. Therefore, for fine-grade coal gangue particles, jigging under the Fuller distribution demonstrates better effectiveness than under the RRSB distribution.

Characterization of the airborne aerosol inlet and transport system used during the A-LIFE aircraft field experiment

Abstract. Atmospheric aerosol particles have a profound impact on Earth's climate by scattering and absorbing solar and terrestrial radiation and by impacting the properties of clouds. Research aircraft such as the Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR) Falcon are widely used to study aerosol particles in the troposphere and lower stratosphere. However, transporting a representative sample to the instrumentation inside the aircraft remains a challenge due to high airspeeds and changing ambient conditions. In particular, for high-quality coarse-mode aerosol measurements, knowledge about losses or enhancements in the aerosol sampling system is crucial. In this study, the sampling efficiency of the aerosol inlet aboard the Falcon research aircraft is characterized for the first time with state-of-the art in situ measurements including sizing instruments operated behind the Falcon aerosol inlet and mounted at the aircraft wing not affected by the aerosol inlet. Sampling efficiencies were derived for different true airspeed ranges by comparing the in-cabin and ”full”-size-range particle number size distributions during 174 flight sequences with a major contribution of mineral dust particles during the ”Absorbing aerosol layers in a changing climate: aging, lifetime and dynamics” project (A-LIFE). Additionally, experimentally derived Stokes numbers were used to calculate the cutoff diameter of the aerosol sampling system for different particle densities as a function of true airspeed. As expected, the results show that the velocity of the research aircraft has a major impact on the sampling of coarse-mode aerosol particles with in-cabin instruments. For true airspeeds up to about 190 m s−1, aerosol particles larger than about 1 µm are depleted in the sampling system of the Falcon during the A-LIFE project. In contrast, for true airspeeds higher than 190 m s−1, an enhancement of particles up to a diameter of 4 µm is observed. For even larger particles, the enhancement effect at the inlet is still present, but inertial and gravitational particle losses in the transport system get more and more pronounced, which leads to a decreasing overall sampling efficiency. In summary, aerosol particles are either depleted or enhanced in the Falcon aerosol inlet, whereas transport in sampling lines always leads to a loss of particles. Here, we have considered both effects and determined the cutoff diameter for the A-LIFE transport system (i.e., the sampling lines only), the cutoff diameter of the Falcon aerosol inlet (i.e., the effect of the inlet only), and the combined effect of the inlet and sampling lines.

Wind Tunnel Test of Sand Particle Size Distribution along Height in Blown Sand

In aeolian sand movement, the vertical distribution of sand particle size is intricately linked to sand flux, wind–sand flow field and dune development. In the present study, the distribution characteristics of sand grains in four particle size ranges at nine heights were investigated through sand blowing tests at five different reference wind speeds. The correlation between sand particle size and wind speed indicates that when the particle size was ≥0.35 mm, there was a linear variation of mass percentage with wind speed. When the particle size was <0.35 mm, when Z ≤ 0.15 m, a linear variation of mass percentage with wind speed was found; when Z > 0.15 m, an exponential modification in mass percentage with wind velocity was observed for sand grains falling within this specific range of particle sizes. The correlation between sand particle size and height indicates that when the reference wind speed was ≥15 m/s, the mass percentage of sand particles varied linearly with height. When the reference wind speed was ≤13.5 m/s, the mass percentage of sand grains with particle size in the 0.25–0.35 mm range increases first and then decreases with increasing height. The present results can provide a reference for subsequent research on the aerodynamic characteristics of wind–sand flow fields and on the mechanism of dune formation.

Prediction of water absorption of recycled coarse aggregate based on deep learning image segmentation

Abstract To quickly measure the water absorption (WA) of Recycled Coarse Aggregates (RCA), we utilize a detection platform designed for RCA to collect two-dimensional images. Utilizing the RCA-net network, we segment the areas of the mortar and aggregate on the RCA surface. Segmentations allow us to extract critical parameters for characterizing the quality of RCA, the proportion of mortar area (PMA). Subsequently, we construct three regression functions between PMA and WA. The experimental results demonstrate that our proposed segmentation method effectively separates both adhered particles of RCA and distinct areas of mortar and aggregate on RCA surfaces. Next, sprinkling water on RCA surfaces can enhance the accuracy of the segmentation. Notably, within particle size ranges of 5–10 mm, 10–20 mm, and 20–31.5 mm, we all observed a significant linear relationship between PMA and WA. We used those linear relationships and the equivalent mass of RCA detected by the image method in each particle size range to construct the prediction model of water absorption. According to the validation result of 24 groups RCA, this model’s maximum relative error of RCA water absorption predicted value was 10.6 %. The detection time of this method is short, and the detection time of 2 kg RCA is 3.8 min, with an average computation time per image of merely 0.659 s. This efficiency fulfills the requirements for real-time industrial inspection.

Calculation of trapping optical forces induced by a focused continuous Hermite Gaussian beam on a nano-dielectric spherical particle

An analytical expression for the intensity distribution of a focused continuous Hermite Gaussian beam after passing through a positive lens has been derived. Analytically, this intensity has been used to derive the gradient force acting on a nano-dielectric spherical particle . It is found that, the beam modes (p, l) have a direct influence on the trap stability, the number of trapping regions, the area of trapping zones and the particle size range.

DESIGN AND DEVELOPMENT OF NANOEMULSION OF SMILAX CHINA FOR ANTI-PSORIASIS ACTIVITY

Objective: The present investigation aimed to prepare a smilax china loaded nanoemulsion using tween 80 as a surfactant and propylene glycol as a co-surfactant. Formulation of such drugs in nanoparticulate drug delivery will be advantageous for reducing dosing frequency, longer residence time, improved permeation, and patient compliance. Methods: High-speed homogenization method. The smilax china oil was prepared by collecting the extract of smilax china leaves into the coconut oil and then used as a solvent. The authentication studies of smilax china and coconut oil were evaluated for their organoleptic and physicochemical characteristics. The quantitative estimation and pre-formulation study of quercetin was carried out which has major anti-psoriatic properties. Surfactant and co-surfactant were selected and the solubility studies of oil and Surfactants were done. The nanoemulsion was characterized by particle size, polydispersity index, zeta potential, and entrapment efficiency (%). Results: This nanoemulsion provides the particle size and entrapment efficiency range between 80.52 to 89.78 nm and 68.66 to 70.16 % respectively. Batch SC1 showed the lowest particle size, PDI, and optimized drug entrapment effectiveness (%), indicating good particle size consistency within the remaining formulation batches. The optimized formulation SC 1 was found to be stable for 90 d. Conclusion: The formulated nanoemulsion showed significant antipsoriasis activity due to the presence of quercetin which has a rhetorical yield of 1.066 mg per 5 gm powder of smilax china leaves. Formulated smilax china-loaded nanoemulsion, has the potential as an effective antipsoriasis agent with a good spreading property with faster absorption which is beneficial for reducing drug concentration with maximum therapeutic effect.

Continuous pipe-stream self-assembly technology for preparation of high sphericity FOX-7/HMX energetic composite microspheres

The emphasis on producing high-energy and insensitive composite microspheres has increased in energetic materials. However, few methods are available for preparing good spherical and morphological composite microspheres. To produce composite microspheres that are both high-energy and safe, in this article, a continuous pipe-stream self-assembly device was constructed to produce FOX-7/HMX composite microspheres continuously and taking advantage of the principle that PVA and Tween-80 can reduce the surface tension of the microspheres in water. In comparison with the molding powders produced by the kneading way, the FOX-7/HMX composite microspheres prepared by this device had fewer surface defects, a denser structure, a more spherical shape, and a smaller range of particle sizes. The mechanical properties of the pressed columns were better, with maximum compressive strength and strain increased by 44.2% and 21.4%, respectively; and the flowability and bulk density were also improved to some extent (angle of repose: energetic microspheres vs kneading method molding powder, 26.6° vs 51.1°; bulk density: energetic microspheres vs kneading method molding powder, 0.522 vs 0.426 g/cm3). Mechanical sensitivity has also been significantly reduced. This article provides innovative ideas for preparing high-energy and insensitive composite microspheres using a continuous pipe-stream self-assembly device.

Crack development and fracture performance of Recycled Powder Engineered Cementitious Composites (ECC): Experimental investigation

In this paper, recycled concrete powder (RCP) and recycled brick powder (RBP), with particle sizes ranging from 10 to 130 μm, are used to completely replace the fine aggregate quartz sand at a ratio of 1:1. On this basis, recycled glass powder (RGP), with a discussed particle sizes range of 38–300 μm, is used to partially substitute the cementitious materials. Polyethylene (PE) fibers are used as the reinforcement in the Engineered Cementitious Composites (ECC). Using the particle size range and substitution rate of RGP as variables, the crack development, crack mouth opening displacement (CMOD), fracture toughness and fracture energy of Recycled glass powder ECC (RGP-ECC) were discussed through a three-point bending experiment on a single-edge notch beam. A relatively comprehensive evaluation was made on the fracture performance and behavior of recycled ECC, and a suitable mix ratio of recycled powder ECC was given. The results show that the addition of various recycled powders will not affect the multi-slit cracking behavior of ECC, and the cracks can still spread densely, giving the specimen greater deformation capacity and CMOD. The total substitution of fine aggregate by RCP and RBP has a positive impact on the fracture toughness KICini, KICun and fracture energy (GF), but the addition of RGP has some minor negative effects. Among the particle size range and substitution rate of RGP, the influence of substitution rate is more obvious, and the fracture performance will show a downward trend after growth as the substitution rate increases. Choosing the appropriate RGP substitution rate and particle size range can maximize the recycling of construction waste while ensuring fracture performance.

Optimization and Bioactive Properties of Nanoemulsion Formulated with Hemp (Cannabis sativa L.) Seed Oil and Aloe vera (Barbadensis miller Stockton) Gel

AbstractThe use of nanoemulsions, a nanotechnology technique, is very popular in the food industry to extend the shelf life of foods and preserve their quality. In this study, it was aimed to develop, optimize, and determine the bioactive properties of nanoemulsion containing Aloe vera gel (AVG) and hemp seed oil (HSO) for use in the food industry. Nanoemulsions containing different ratios of AVG (1 %, 2 %, and 3 %) and HSO: Tween 80(T80) (1 : 4; 20, 25, 30 %) were formulated by ultrasonication. Bioactive properties of nanoemulsions were determined by droplet size, polydispersity index (PDI), zeta potential, Transmission electron microscopy (TEM) imaging, Fourier transform infrared spectroscopy (FT‐IR), viscosity, color, whiteness index, turbidity, conductivity, pH, antioxidant (DPPH), and antimicrobial activity analyses. The pH of the nanoemulsions was between 4.74 and 4.88 due to the acidic nature of AVG. PDI was determined in the 0.17 (HA8) range to 0.26 (HA1). According to the FT‐IR spectrum, it was determined that the entire nanoemulsion formulation did not undergo any chemical degradation and their particle sizes (range between 118.9 nm and 170.5 nm) were <200 nm. The small droplet size and PDI values obtained showed that the nanoemulsions had a homogeneous and stable structure in their dispersions. TEM results determined that all nanoemulsions showed a spherical shape, but the structure detected in the HA8 group had a more homogeneous appearance. The antioxidant activity of the nanoemulsions increased depending on the increasing HSO and AVG percentages. Unfortunately, no antibacterial activity of the nanoemulsions was detected against any of the bacterial strains tested. According to the analysis results, it was determined that the best nanoemulsion formulation belonged to the HA8 group containing 3 % Aloe vera gel and 5 % HSO in terms of TEM and PDI analyses.

Formulation of microsponges of anti-fungal drugs and their pharmacokinetic and in vitro analysis

Microsponges are uniform, spherical, porous polymeric microspheres having myriad interconnected voids of particle size range 5-300 μm. These microsponges have the capacity to entrap a wide range of active ingredients such as emollients, fragrances, essential oils, sunscreens and anti-infective, etc. and then release them onto the skin over a time in response to a trigger. Microsponge Delivery System (MDS) can be used to resolve the problem associated with these conventional approaches. The drug entrapped microsponges can be incorporated into a formulated product, such as a gel, cream, liquid or powder. Microsponge is as tiny as a particle of talcum powder. Although they are microscopic in size, these systems are too large to pass through the stratum corneum thus preventing excessive accumulation of drugs within the epidermis and dermis, and hence systemic entry of the drugs. They increase the rate of solubilization of poorly water soluble drugs by entrapping such drugs in pores of the microsponges. In this study, Flutrimazole and Oxiconazole nitrate microsponge were prepared by quasi-emulsion solvent diffusion method. The microsponges thus prepared, were evaluated for production yield, loading efficiency, particle size analysis, SEM, IR, DSC, PXRD, characterization of pore structure, in-vitro release study of microsponges, and stability. Then, gels loaded with microsponge and plain drug were formulated and evaluated for rheology, diffusion, skin irritation and antifungal activity. Antifungal activity of Flutrimazole and Oxiconazole nitrate containing microspongic gels were compared with marketed formulations. The microsponges showed good production yield, loading efficiency and particle size. All characteristic peaks of the drugs were concordant with IR spectra of pure drugs. PXRD and DSC studies revealed amorphization of drugs. SEM images showed that styrene microsponges prepared by suspension polymerization were finely spherical and uniform, while Eudragit microsponges prepared by quasi-emulsion solvent diffusion method were comparatively less spherical. According to intrusion and extrusion curves, majority of the pores present in Eudragit microsponges were spherical type, whereas the pores of styrene microsponges were mainly cylindrical-hole type. BET multipoint adsorption isotherm studies revealed that the percent of porosity of styrene microsponges is comparatively higher than Eudragit based microsponges. During the storage of drug-entrapped microsponges at 40±2°C and 75±5% RH for 6 months, surface morphology and release of drug showed no notable changes. Viscosity determination of gel showed that gels loaded with microsponge are more viscous than gel loaded with plain drug. The controlled drug release was observed with all the microspongic gels. Antifungal activity of gels containing microsponge entrapped Flutrimazole and Oxiconazole nitrate showed that antifungal activity of drugs was retained even after entrapment in microsponges and it was higher as compared with the gel containing free drug and marketed formulation. Gels containing drugs entrapped in microsponges.

Pontederia crassipes Biosynthesised Silver Nanoparticles (AgNPs), Characterisation and Activity against Multidrug-Resistant Microbes

Introduction: Pontederia crassipes (water hyacinth) has been singled out as one of the major causes of enormous economic and ecological losses to tropical water systems and habitats. Almost impossible to eradicate, the ominous species is characterized by rapid multiplication, giving rapid and extensive spread that can choke entire rivers and water bodies. However, vast, diverse bioactive secondary metabolites are found in P crassipes which exhibit an expansive assortment of antibacterial properties used in traditional medicine. The rapid emergence of Multi Drug Resistant (MDR) pathogens to common drugs is a pandemic of global proportions. Global health institutions are calling for a coordinated, global action plan to develop new biomaterials to combat the rising threat by MDR strains and improve treatment outcomes and save lives. This study proposes consumption of the water hyacinth lily species through a novel, material biosynthesis approach not only to manage the aquatic infestation but to develop advanced multifunctional, anti-microbial Silver nanoparticles through bio-reduction and capping of Silver salts targeted at MDR microbes. Methodology: After screening for active phytoconstituents of P.crassipes. The Biosynthesis of Novel AgNPs mediated by phenolic, antibacterial lyophilized hydro-ethanolic extracts from P crassipes as both bioreduction and capping agents was investigated. The resultant AgNPs characteristics, toxicological profiles and the antibacterial effects on 10 common microbes including MDR bacterial strains were evaluated. Observations and Results: TEM revealed that cubic and spherical nanometric AgNPs structures were successfully synthesized with particle size range from 10-60nm. With an average zone of inhibition of 29mm and an MIC of 6.25 µg/ml .The nanoparticles were efficacious against selected MDR strains and common infectious bacterial strains tested. In-vivo acute oral toxicity evaluations confirmed the safety of P crassipes. Conclusion: Biogenic P.crassipes mediated AgNPs are feasible, safe and efficacious and have immense potential for optimization into efficient broad spectrum MDR antibacterial agents.b

Compatibility, Microstructure, and Mechanical Properties of a Dimethyl-Sulfoxide-Pretreated Graphene-Modified Asphalt Binder.

The surface of graphene was pretreated with dimethyl sulfoxide to enhance its dispersion in asphalt. To investigate the compatibility, microstructure, and mechanical properties of a dimethyl-sulfoxide-pretreated graphene (DG)-modified asphalt (DG asphalt). The interaction between asphalt and DG, DG dispersion, functional groups, tensile performance, microscopic structures, and micromechanical properties of the DG asphalt were characterized. Results indicate that DG with a particle size range from 0 to 8 μm is uniformly dispersed in asphalt. The irregular distribution of DG enhances the stress transfer distance, thus improving the energy consumption and mechanical properties of the DG asphalt. The preparation process involves physical blending, which reduces the saturated hydrocarbon content and increases the chemical bond energy, ultimately enhancing mechanical properties. Additionally, the surface of the DG asphalt shows numerous smaller sized bee structures, which contribute to the hardening and smoothness of the asphalt surface. The stress is distributed uniformly across the surface of the DG asphalt, minimizing stress concentrations. Furthermore, the light components in asphalt are adsorbed by DG, forming intercalated structures that decrease the adhesion and energy dissipation when compared to base asphalt. The compressive stress within bee structures consumes more energy and enhances the anti-deformation capacity of the DG asphalt. However, at higher deformation levels, the slipping of intercalated DG decreases its anti-deformation capacity when compared to that of base asphalt. Nonetheless, the interaction between intercalated structures prevents rapid tensile failure in the DG asphalt.

A captivating approach to elevate the detection of Al3+ ions incorporates the utilization of a tripodal receptor intricately embellishing the surface of zinc oxide

The FDA (Food and Drug Administration, (USA)) lists ZnO as a material that is widely acknowledged to be safe. ZnO NPs with a range of tiny particle sizes were made using the precipitation process. ZnO nanoparticles' surface is embellished with a tripodal sensor containing naphthol units. The assembly with the same receptor decorated on ZnO NPs is contrasted with the cation detection capabilities of the purified tripodal receptor. The UV–visible spectrophotometric analysis was conducted to study the state transitions of the receptor and the decorated ZnO receptor. A positive selectivity to Al3+ cations is determined by the fluorescence study under ideal circumstances. The particle size and surface morphologies are determined by DLS and SEM analysis for the same receptor − TP1 and embellished with a tripodal receptor TP2. Using a fluorescence switch-on Photoinduced Electron Transfer (PET) mechanism, the receptor coated on ZnO detects the presence of Al3+ ions with specificity. The binding constant value was determined using the B-H plot equation. Binding stoichiometry for [TP1-Al3+, TP2-Al3+] showed a 1:1 ratio. The fluorescence switches ON-OFF process of the ZnO surface adorned − TP2 with Tripodal receptor- TP1 was used to create molecular logic gates, which can function as a module for sensors and molecular switches. The addition of Na2EDTA in the solution of the [TP1; TP2 − Al3+] complex resulted in a noticeable reduction in the emission of fluorescence. This finding offers compelling support for the reversibility of the chemosensor. To enable the practical application of this sensor, we have developed a cassette containing receptors TP1 and TP2. Successfully, it can detect Al3+ metal ions. We performed a comprehensive assessment of the dependability and appropriateness of our approach in measuring the concentration of Al3+ ions in wastewater produced by important industrial procedures.

A study on particle size of slag on properties of magnesium potassium phosphate cement

AbstractMagnesium potassium phosphate cement (MKPC) presents a broad application prospect in engineering fast repairing, reinforcement, hazardous material, and national defense construction, due to its good properties such as fast hardening and early strength, high bonding strength, and wide environmental adaptability. In this work, the effect of slag with different particle size on the workability, mechanical properties, and hydration products of MKPC was investigated. The results showed that the compositions of slag in the particle size range 75–300 µm are quite different. A decrease in the particle size of slag resulted in reduction of the fluidity of MKPC from 175 to 108 mm and shortening the setting time from 1300 to 850 s. The compressive strength of MKPC (curing for 3 h) does no change much as the particle size of slag varies, and slag with the particle size in the range of 115–300 µm slightly increase the 3‐h‐compressive strength of MKPC, since the compressive strength values are in the vicinity of 13 ± 2 MPa. As the curing age increases, physical effect and hydration activity of slag concurrently dominate the mechanical properties of MKPC, and when the hydration activity of the slag exceeds the adverse effect caused by fine particles, the compressive strength increases. Slag particle size can significantly improve the long‐term compressive strength of MKPC, which can effectively reduce the cost and can be used as a repair material with better durability.

Effects of Particle Size Distribution on the Physicochemical, Functional, and Structural Properties of Alfalfa Leaf Powder

To explore the effects of particle size distribution on its physicochemical, functional, and structural properties, alfalfa leaf powders with mean particle sizes (D50) of 506.1, 246.3, 209.8, 92.01, and 20.68 μm were prepared by sieving. The physicochemical, functional, and structural properties of alfalfa were compared, and correlation and principal component analyses were conducted. As the D50 of alfalfa leaf decreased, the bulk density, tap density, and the swelling capacity increased first and then decreased, but the compressibility, transition temperature, and melting temperature exhibited an opposite trend. The solubility, lightness, and inhibition of angiotensin-converting enzymes and tyrosinase were enhanced. Specifically, the alfalfa leaf with a D50 of 209.8 μm exhibited a higher bulk density and swelling capacity and a lower compressibility, transition temperature, and melting temperature. The alfalfa leaf with a D50 of 20.68 μm presented better solubility, lightness, and inhibition of angiotensin-converting enzymes and tyrosinase. Additionally, the surface roughness and the number of surface hydroxyls improved and the crystallinity index decreased, but the type of surface functional groups was unchanged. These changes in microstructure can provide an explanation for the trend of the physicochemical and functional properties. Moreover, based on the results of the correlation analysis and principal component analysis, it can be concluded that there are strong correlations among the particle size, physicochemical properties, and functional properties of alfalfa leaf. Overall, this conclusion can help determine the appropriate grinding particle size range for alfalfa leaf in different functional food products.

Structural optimization of diblock polymers that undergo thermo-responsive nanoparticle self-assembly for intravitreal drug delivery

Certain diseases of the eye require frequent intravitreal injections to sustain active drug concentrations due to the limited volume (≤50 µL) of solution that can be administered each injection. Drug delivery systems have been evaluated to reduce dosing frequency but achieving (i) high concentrations with low viscosity (<100 cP) and (ii) narrow range of particle size (∼20–70 nm) to prolong drug activity without affecting vision remain major challenges. To address these challenges, we synthesized a combinatorial library of thermo-responsive polymer-drug conjugates with diblock architecture and assessed how various parameters (monomer unit composition, block length, drug density and attachment site) affect properties impacting ocular injection suitability. Our screens identified a lead composition, p[(N-isopropylmethacyrlamide)–co-(N-benzylmethacrylamide)]-b-p(N-(2-hydroxypropyl)methacrylamide) with 20 mol% N-benzylmethacrylamide (p[(NIPMAM)–co-(BnMAM)]-b-p(HPMA)), that exists as unimers at room temperature that can be highly concentrated (200 mg/mL) and injected at low viscosity but self-assemble into 20–70 nm particles upon injection into vitreous humor at body temperature. Furthermore, covalent attachment of representative small molecule, peptide- and protein-based drugs had minimal to no impact on thermoresponsive and hydrodynamic behavior highlighting the versatility of the lead composition as a platform for delivering a broad range of different drug molecules.

Potential of powder metallurgical methods to fabricate Fe-6.5Si soft magnetic components

The soft magnetic Fe-6.5Si alloy is well known for its excellent soft magnetic properties but its usage is limited due to fabricational constrains by conventional methods. Powder metallurgical processing of Fe-6.5Si is possible by a variety of different methods shown here, sinter-based screen printing (SP), electron beam powder bed fusion (E-PBF) and field-assisted sintering (field-assisted sintering/spark plasma sintering, FAST/SPS). The microstructure of the components varies strongly by process and powder used which is directly influencing their soft magnetic properties. The correlation between powder properties and processing parameters on the structural and magnetic properties is established. Lowest coercivity ( H c = 7 A m−1) is achieved by E-PBF due to large grain size minimising hysteresis losses necessary for direct current applications. SP can provide sheets with low coercivity ( H c = 21 A m−1) and adjustable thickness reducing eddy current losses especially suitable for alternating current application at higher frequencies. FAST/SPS can be used for a large range of powder particle sizes which is suitable to tune the soft magnetic properties in a wide range between 40 and 210 A m−1.