Solid Particles Research Articles

New Insights into Pharmaceutical Nanocrystals for the Improved Topical Delivery of Therapeutics in Various Skin Disorders.

Nanotechnology has provided nanostructure-based delivery of drugs, among which nanocrystals have been investigated and explored for feasible topical drug delivery. Nanocrystals are nano-sized colloidal carriers, considered pure solid particles with a maximum drug load and a very small amount of stabilizer. The size or mean diameter of the nanocrystals is less than 1 μm and has a crystalline character. Prominent synthesis methods include the utilization of microfluidic- driven platforms as well as the milling approach, which is both adaptable and adjustable. Nanocrystals have shown a high capacity for loading drugs, utilization of negligible amounts of excipients, greater chemical stability, lower toxic effects, and ease of scale-up, as well as manufacturing. They have gained interest as drug delivery platforms, and the significantly large surface area of the skin makes it a potential approach for topical therapeutic formulations for different skin disorders including fungal and bacterial infections, psoriasis, wound healing, and skin cancers, etc. This article explores the preparation techniques, applications, and recent patents of nanocrystals for treating various skin conditions.

Effects of prepulse on hot electron emission from mesoscopic particles

In this paper we make an attempt to study the effect of a nanosecond prepulse on electron acceleration from microscopic solid particles. While standard scaling laws predict temperatures of ∼50 keV, our investigations showed an anomalous enhancement ( ∼200 keV) in electron temperatures from microscopic solids subjected to intense laser fields. Conventional isotropic expansion of the plasma target as a result of pre-pulse interaction is unable to explain the enhancement, prompting an experimental inquiry into the expansion form. Tentacle-like structures emerging from the spherical plasma are detected as an outcome of the pre-pulse interaction, with the region between the tentacles being targeted by the main laser pulse. We resort to PIC simulations to understand and predict the exact plasma condition that exists in this region. In this paper, we study a series of approximate pre-plasma conditions, particle shapes, and electron densities, examining them for their role in electron acceleration from this extended over-critical plasma target.

Tailoring stability in oil-in-water high internal phase Pickering emulsions (HIPPEs) through surface modification of beeswax-based solid lipid particles (SLPs) with various surfactants

As high-performance Pickering stabilizers, the exploration of solid lipid particles (SLPs) for oil-in-water high internal phase emulsions (HIPPEs) has garnered significant interest in the colloid domain, primarily owing to their promising applications in the food industry. Herein, as an underutilized and cost-effective food processing resource, beeswax (BW) was probed, and BW-SLPs was tuned by controlling the different type (Na-Cas or T80)/concentration (0.5–2.5 wt%) of surfactant with a view to stabilizing the HIPPEs (φ = 0.80) more effectively. At concentrations of 0.5–2.0 wt%, a more stable semi-solid HIPPEs could be formed by Na-Cas-BW-SLPs, while phase separation occurred at 2.5 wt%. However, T80-BW-SLPs could only form the fluid dynamic emulsions. The correlation between the interfacial characteristics of SLPs and the physical properties of SLPs-stabilized HIPPEs was thoroughly investigated. Microscopic images showed that Na-Cas-BW-SLPs formed a closely packed three-dimensional network structure around the oil droplets but aggregated in the aqueous phase at the concentration of 2.5 wt%. And they exhibited the capacity to improve the viscoelasticity of the interfacial film, which also endowed the HIPPEs with excellent rheological properties. While, T80-BW-SLPs were loosely arranged, formed a viscous film on the interface, and G′ of the interfacial film was about 2 orders of magnitude lower than Na-Cas-HIPPEs at the same concentration. Besides, transmission electron microscopy (TEM) analysis revealed that the Na-Cas-BW-SLPs (∼370 nm), unlike the out of shape T80-BW-SLPs (∼230 nm), exhibited a cross-linked structure with a rough surface. All SLPs demonstrated enhanced wettability and a remarkable ability to reduce interfacial tension (2 mN/m). Additionally, it further identified the inability to form stable HIPPEs up to φ = 0.84 at the optimal Na-Cas-SLPs concentration. Ultimately, the HIPPE stabilized by 3.0 wt% BW and 2.0 wt% Na-Cas, with oil fraction up to 83 vol%, exhibited the highest elastic modulus (3871.0 Pa) and demonstrated exceptional stability over a 30-day storage period.

Erosive Wear Caused by Large Solid Particles Carried by a Flowing Liquid: A Comprehensive Review

The erosive wear encountered in some industrial processes results in economic loss and even disastrous consequences. Hitherto, the mechanism of the erosive wear is not clear, especially when the erosive wear is caused by large particles (>3.0 mm) carried by a flowing liquid. Current approaches of predicting erosive wear need improvement, and the optimization of relevant equipment and systems lacks a sound guidance. It is of significance to further explore such a subject based on the relevant literature. The present review commences with a theoretical analysis of the dynamics of large particles and the fundamental mechanism of erosion. Then the characteristics of the erosion of various equipment are explicated. Effects of influential factors such as particle size and properties of the target material are analyzed. Subsequently, commonly used erosion models, measurement techniques, and numerical methods are described and discussed. Based on established knowledge and the studies reported, some expectations for future work are proposed.

Preparation and Performance Study of Rapid Repair Epoxy Concrete for Bridge Deck Pavement.

With the rapid development of bridge construction, the service life of bridges and traffic volume continue to increase, leading to the gradual appearance of diseases such as potholes and cracks in bridge deck pavements under repeated external loads. These issues severely impact the safety and service life of bridges. The repair of bridge deck potholes and cracks is crucial for ensuring the integrity and safety of bridge structures. Rapid repair materials designed for this purpose play a critical role in effectively and efficiently addressing these issues. In order to address the issues of pavement diseases, this study focuses on the rapid repair of epoxy concrete for bridge deck pavements and its performance is studied using experimental methods. Firstly, carbon black, rubber powder, and other materials were used to improve the elastic modulus and aging resistance of the epoxy concrete. Secondly, the addition of solid asphalt particles provided thermal sensitivity to the repair material. Finally, various properties of the rapid repair epoxy concrete for bridge deck pavements were tested through experiments including compressive strength testing, elastic modulus measurement, thermal sensitivity testing, and anti-UV aging testing. The experimental results show that adding carbon black and rubber powder reduces the elastic modulus of epoxy concrete by 25% compared to normal epoxy concrete, while increasing its aging resistance by 1.8%. The inclusion of solid asphalt particles provided thermal sensitivity to the repair material, contributing to better stress coordination between the repair material and the original pavement material under different temperature conditions. The epoxy concrete has early strength, toughness, and anti-aging properties, making it suitable for rapid repair of bridge deck pavement.

Solid-liquid particle flow sealing mucus (PFSM) in enhancing coalbed methane (CBM) recovery: Multiple-perspectives analysis and mechanism insights

The paper presents an in-depth investigation of solid-liquid two-phase particle flow sealing mucus (PFSM) for enhanced coalbed methane (CBM) recovery. PFSM is composed of solid waste particles such as fly ash and rubber particles. The PFSM is assessed using multiple-perspectives analysis, which includes measurements of water retention, pressure expansion, rheological characteristics, adhesion, wettability, microscopy and field case studies. Single-factor and multi-factor studies are used to optimize slurry material ratios. The results show that PFSM has outstanding water retention characteristics, with over 80 % retention for 30 days at 30 °C, and impressive expansion performance, with 9.52 % at 0.6 MPa. The shear thinning curve conforms to the Cross model. After 30 s, the final contact angle is 75.17 °, which is about 6 ° smaller than that of cement based materials. Field experiments show that, after applying PFSM, the drainage gas concentration can be improved at least 60 % comparing to other sealing materials. This research findings could offer novel insights into enhancing CBM extraction, indicating potential for safer and more efficient coal mine production.

Investigating Potential Sources of Sore Throat: Physico-Chemical Attributes and Microbial Contamination in Rambutan from Fresh Harvests and Retail Stores

Rambutan (Nephelium lappaceum), a tropical fruit cherished for its succulent flesh and vibrant appearance, is cultivated extensively across various regions worldwide. However, despite its popularity, the fruit faces challenges related to particulate contamination during the harvesting process. Particulate matter contamination refers to the presence of solid or liquid particles suspended in the air or adhered to the fruit's surface, posing potential risks to both consumer health and fruit quality. Hence, this study aims to identify the factors in rambutan that could cause sore throats by analysing its physicochemical properties and conducting a microbiological study. For this study, two samples of rambutan fruit which are rambutan sold in stores (RS) and rambutan freshly harvested from the tree (RT) were collected and analysed for their external peel, internal peel, and pulp parts (n = 3). The assessment included the weight of visible fine dirt, pH value, oil content, surface morphology and total coliform (TPC). The results showed that the weight of visible fine dirt on RT external peel (93.50 ± 5.00 mg) and the pH value of its external peel and pulp (4.17 ± 0.00 - 5.17 ± 0.00) were significantly higher and more acidic (p<0.05) than those of RS. However, there were insignificant differences (p>0.05) in oil content (0.36 ± 0.7 - 0.38 ± 0.8%) between the external peels of the rambutan samples. Additionally, the surface morphology and image analysis of RS showed more foreign particles, represented as black or white dots on its internal peel and pulp, compared to RT, which was suspected to be yeast. Moreover, the total coliform count for both samples was significantly different (p<0.05) in their external peel and pulp, but it was still within the safe eating limit. The study concluded that environmental pollution and contamination during rambutan handling could cause sore throat.

Inward motion of diamond nanoparticles inside an iron crystal

In the absence of externally applied mechanical loading, it would seem counterintuitive that a solid particle sitting on the surface of another solid could not only sink into the latter, but also continue its rigid-body motion towards the interior, reaching a depth as distant as thousands of times the particle diameter. Here, we demonstrate such a case using in situ microscopic as well as bulk experiments, in which diamond nanoparticles ~100 nm in size move into iron up to millimeter depth, at a temperature about half of the melting point of iron. Each diamond nanoparticle is nudged as a whole, in a displacive motion towards the iron interior, due to a local stress induced by the accumulation of iron atoms diffusing around the particle via a short and easy interfacial channel. Our discovery underscores an unusual mass transport mode in solids, in addition to the familiar diffusion of individual atoms.

A Mathematical Modelling of Solid Particles Transport in Two-Zone Porous Media with Non-Linear Kinetics of Deposition

A Mathematical Modelling of Solid Particles Transport in Two-Zone Porous Media with Non-Linear Kinetics of Deposition

Experimental Study on Vacuum Distillation Separation Characteristics of Tar Containing Solid Particles: Distributions of Light Components.

The impacts of the composition and properties of tar products on their utilization are of great importance, while the consequences of varying tar separation conditions on distillation fractions remain underexplored. Solid impurities in special tar products (e.g., subsurface in situ pyrolysis-derived tar-like substances) can contribute to the separation as well. In the present study, low-temperature coal tar (LTCT) was used as an analogue to pyrolysis product, mixed with semi-coke and coal dust, representing pyrolytic byproducts and nonpyrolytic substances, respectively. The LTCT mixtures were tested with vacuum distillation at various pressures and temperatures. The results revealed the role of pressure in fraction distribution across temperatures, with higher pressure concentrating fractions at lower temperatures. The impact of solid impurities on distillation primarily stemmed from adsorption. Minimal concentrations of solid impurities carried coal dust/semi-coke into the distillation, but higher levels retained them in the residue. The adsorption of coal dust was quite high at lower temperatures and waned as temperature increased, unlike semi-coke, which had consistent adsorption throughout the distillation. The present study can advance the understanding of vacuum distillation for tar products in the presence of solid impurities, offering a framework for the effective distillation/utilization of coal tar. By probing separation conditions, tar properties, and solid impurity effects, the present research will refine strategies for optimizing coal tar use, crucial for enhancing energy security and sustainable progress in China.

Microfiber emission from a municipal wastewater treatment plant in Hungary.

Since the ingestion of both natural and anthropogenic microfibers produces a deleterious effect on aquatic organisms, it is crucial to explore the emission of these pollutants by WWTPs into the receiving water bodies, such as rivers. Cellulose- and petroleum-based microfibers, as well as microplastic particles, were collected from the effluent of a municipal WWTP operating with activated sludge technology in Budapest, Hungary. During two sampling campaigns organized in February and April of 2023 on different working days and at different times of the day, 123-145 L of effluent was sieved and filtered. The organic matter was removed by hydrogen-peroxide treatment. All fibers and particles larger than 10µm were counted, and using a fluorescence microscope, the fibers were geometrically characterized in terms of length and diameter. Each fiber was individually identified by transflection-FT-IR method. The fiber concentration varied in the range of 1.88-2.84 and 4.25-6.79 items/L during the 7th and the 16th week of 2023, respectively. In February and April, the proportion of microfibers in the solid particles was 78.3 and 94.7%, respectively. In the effluent the cellulose-based microfibers were dominant (53-91%), while among the petroleum-based microfibers, polyester occurred most often. The median length of cellulose-based fibers was considerably higher in April than in February (650 vs. 1250µm), and simultaneously the median diameter also increased from 21 to 29µm. This behaviour was also seen, albeit to a lesser extent, in connection to microfibers derived from petroleum. The treated wastewater's daily microfiber transport to the Danube River varied between 0.44 -0.69 and 0.94-1.53 billion in February and April 2023, respectively.

Effects of food waste hydrolysate as an external carbon source on defoaming in wastewater treatment with activated sludge process

The activated sludge process is the most widely used technology for treating municipal wastewater. However, thick foam often occurs in activated sludge process. Here, we reported for the first time the effect of food waste hydrolysate (FWH) as an external carbon source on defoaming in activated sludge process. The study found that FWH was effective in defoaming at a wide dose range of 50–1600 mg/L total solids, as exhibiting that the foaming tendency of FWH-added foam mixed liquor was reduced to 0 mL-foam/mL-air·min from initial 0.171 mL-foam/mL-air·min in the control without adding FWH with 100 % of defoaming efficiency. Fatty acids, oils, and solid particles in FWH jointly contributed to the deformation. Among these factors, the concentration of long-chain unsaturated fatty acids was mainly responsible for the defoaming. This work provides a cost-effective strategy to solve the foaming problem in activated sludge process as well as providing external carbon sources.

Multiphase Numerical CFD Simulation of the Hydrothermal Liquefaction Process (HTL) of Sewage Sludge in a Tubular Reactor

This article presents multiphase numerical computational fluid dynamics (CFD) for simulating hydrothermal liquefaction of sewage sludge in a continuous plug-flow reactor. The discrete particle method (DPM) was used to analyze the solid particles’ interaction in liquid–solid high shear flows to investigate coupling computational fluid dynamics (CFD). Increasing solid particles’ interactions were observed with the increasing liquid velocity. The study examined the influence of parameters such as flow rate, temperature, and residence time on the efficiency of bio-oil production. An increase in temperature from 500 to 800 K caused an increase in the amount of biocrude oil produced from 12.4 to 32.9% within 60 min. In turn, an increase in the flow rate of the suspension from 10 to 60 mL/min caused a decrease in the amount of biocrude oil produced from 38.9 to 12.9%. This study offers insights into optimizing the flow channel of tubular reactors to enhance the HTL conversion efficiency of sewage sludge into biocrude oil. A parametric study was performed to investigate the effect of the slurry flow rate, temperature, and the external heat transfer coefficient on the biocrude oil production performance. The simulation data will be used in the future to design and scale up a large-scale HTL reactor.

DIC-Based Hydration Absorption Detection and Displacement Field Evolution of Outcrop Porous Sandstone

In order to study the hydration absorption behaviors and characteristics of sandstone in Mogao Grottoes in China, the pressure-less hydration absorption experiment on the outcrop porous sandstone of Mogao Grottoes was carried out by using the self-developed real-time monitoring experimental system. The hydration absorption was measured and the curve of hydration absorption with time was drawn. At the same time, the digital image correlation method (DIC) was used to measure the full-field deformation, and the speckle pattern of the sample was analyzed using Match ID, and the displacement field and strain field of the sandstone sample at different hydration absorption moments were computed. Moreover, the sparse area and dense area of sandstone are used as regions of interest (ROI) for DIC analysis. According to the test results, it is concluded that the hydration absorption of sandstone increases rapidly in the initial stage, and gradually tends to be stable with the change of time. This corresponds well with the deformation characteristics of sandstone analyzed using DIC. In the initial stage, the deformation of sandstone increases rapidly. With the change in time, the deformation of sandstone samples gradually slows down. When the hydration adsorption reaches saturation, the sandstone continues to deform for a period of time before stopping hydration absorption. The results of the mercury injection test and the XRD test show that the porosity of the sparse area is larger than that of the dense area and the particle content of the dense area is lower. When the sandstone is saturated with water, the liquid is immersed in the pores between the solid particles, which makes the sparse area more prone to stress concentration, and the deformation in the sparse area is larger. Therefore, when analyzing the hydration absorption deformation of sandstone, the porosity should be considered.

Accumulation of Particles in an Annular Centrifugal Contactor Cascade and the Effect upon the Extraction of Nitric Acid

Centrifugal contactors (CCs) are a technology candidate for the development of advanced reprocessing flowsheets. While they offer many advantages, such as process intensification, there are still uncertainties regarding their industrial deployment. The presence of particles in the process streams in particular may present a challenge to both performance and operability. Preliminary studies have been undertaken to evaluate the accumulation of particles in the contactors and the effect upon the extraction behaviour of nitric acid. Aluminium oxide (Al2O3) particles were suspended in the aqueous feed solution during the operation of a three-stage, 40 mm diameter CC cascade. The presence of insoluble solid particles in the aqueous feed, up to 7 g/L, were not observed to affect phase separation and entrainment under the experimental conditions investigated. The particles were centrifuged out of solution and accumulated as a thin cake/bed in the rotors of each stage. This work also illustrates that particles do entrain through the cascade. The predominant effect on the rate of accumulation was particle concentration in the aqueous feed solution, and increasing solids loading was observed to have an impact upon the extraction of nitric acid across the cascade.

Carbohydrate structural complexity modulates the formation, composition and functionality of microbial flocs and its impact on gut microbiota and growth of Pacific white shrimp

The addition of carbohydrate into the culture water to facilitate the growth of heterotrophic bacteria is a common practice in shrimp grow out culture. The present study aimed to evaluate the effect of carbohydrate structural complexity on the formation, composition and functionality of microbial flocs, and how it impacts the gut microbiome and growth of Pacific white shrimp (Litopenaeus vannamei). Pacific white shrimp juveniles (1.07 ± 0.01 g) were randomly distributed in 12 indoor fiber tanks (50 cm × 50 cm × 100 cm) and maintained for 30 days at stocking density 107 ind.m−3 (20 ind per tank). Three different carbohydrate sources were added according to the treatments, that is dextrose (Dx) representing simple carbohydrate, potato starch (St) representing starch polysaccharide, and cellulose (Cl) representing complex non-starch polysaccharide. Settleable solids level and particle size of microbial flocs in Dx treatment were consistently higher than those of St and Cl treatments (P < 0.05). Amino acids concentrations were not significantly different amongst the treatments (P > 0.05), however essential amino acid index relative to shrimp requirement was the lowest in the Dx treatment (P < 0.05). Shannon diversity index level in the microbial flocs with Cl as the carbohydrate sources was higher compared to Dx and St. T6SS2 and ExsA gene expressions in the co-culture of Vibrio parahaemolyticus and the microbial floc suspension was highly upregulated in Dx treatment. Accordingly, differences in the shrimp gut microbiome was also observed amongst the treatments. The highest growth performance was demonstrated by the shrimp cultured with cellulose as the carbohydrate source. In conclusion, carbohydrate structural complexity could significantly affect the characteristics of microbial flocs suspended in the culture water and could ultimately affect the shrimp growth performance.

Strategies for the quantification and characterization of nanoplastics in AOPs research

There is a growing interest in developing new targeted degradation technologies for the removal of micro- and nanoplastics (NPs) in water, corresponding to increased public concerns regarding their potential negative impacts on urban water systems, and consequently on human life quality. Recently, Advanced Oxidation Processes (AOPs) have been proposed as promising treatment alternatives for effective degradation of NPs in water. However, the selection of appropriate analytical methods for monitoring these oxidation tests remains a challenge. Herein, the feasibility of different characterization strategies for monitoring the evolution of NPs in water upon oxidation tests was systematically studied using polystyrene (PS) NPs of different particle sizes (D0 = 140, 252, 460, and 909 nm) as model plastic pollutants. To quantify NPs in water, Total Organic Carbon (TOC), Chemical Oxygen Demand (COD) and turbidity measurements were assessed. Moreover, turbidity was correlated to the particle size and PS NPs concentration by developing a response surface. Among the analytical techniques employed to characterize the solid particles, transmission electronic microscopy (TEM) was used to evaluate morphology and particle size. Alternatively, the viability of Dynamic Light Scattering (DLS), Nanoparticle Tracking Analysis (NTA) and Atomic Force Microscopy (AFM) to determine particle size is discussed. Chemical surface modifications were explored by Fourier-Transform Infrared Spectroscopy (FTIR). As a proof of concept, the degradation of PS NPs in water upon photo-Fenton oxidation was investigated at ambient conditions and fully characterized using the mentioned techniques.

The Influence of Exogenous Particles on Saliva Rheology

This study aimed to investigate the effect of exogenous nanoparticles on the rheological properties of artificial saliva. There are four reasons for undertaking this type of research: Firstly, the number of solid particles of various origins present in the air is still high. Secondly, nanoparticles (including silver and gold nanoparticles) are increasingly used in food packaging and can migrate into food. Thirdly, saliva is the first biological fluid that comes into contact with exogenous particles. Finally, the function of saliva is also closely related to its rheological properties. Due to the remarkable properties of nano-objects, nanoparticles of various origins in the body may cause effects that have not been realised until now. Therefore, each type of nanoparticle must be tested in terms of its impact on the body/body fluid. We used silver and gold nanoparticles because they are used in the food industry, and diesel exhaust particles because they are standard components of air pollution. The effect of various nanoparticles (e.g., their size and shape) on the rheology of saliva at two temperatures was investigated. The constants of the power law constitutive equation were also estimated. Studies showing the impact of nanoparticles on the rheology of body fluids are rare because it is one of the less obvious ways of their affecting the human body. However, the results show that nanoparticles are not neutral to the biological fluid, which may translate into a change in its properties and thus disturb its functions.

Effects of different solid particle sizes on oat protein isolate and pectin particle-stabilized Pickering emulsions and their use as delivery systems

Oat protein isolate (OPI)/high methoxyl pectin (HMP) complexes (OPP) were prepared to stabilized Pickering emulsions and applied as nutraceutical delivery systems. The different mass ratios and pH changed the interactions between OPI and HMP that caused the different size of OPP. Specifically, smaller particle size of OPP (125.7–297.6 nm) were formed when hydrophobic interactions along with electrostatic forces predominant in OPP (OPI:HMP = 3:1, pH 4, 5). Among these particles, OPP-2 could stabilize Pickering emulsion efficiently through formation of dense interfacial film, which exhibited the highest apparent viscosity and the smallest average droplet size (23.39 μm). Moreover, OPP-2 stabilized Pickering emulsions with superior stability not only exhibited higher encapsulation efficiency of 85.63%, but also could control curcumin release in simulated gastrointestinal fluids to improve curcumin's bioaccessibility. These results verified the possibility of OPP to be a Pickering emulsions stabilizer, and also identified its potential to be a stable delivery system for bioactive compounds.

Investigation on critical erosion of gas production channel for sand carrying during injection and production process in gas storage

Gas wells on underground gas storage typically are operated in high-load mode, with a large working displacement injection and high-strength production. Erosion-corrosion caused by solid particles could cause serious damage to the gas well, leading to tubing column failure and security risks. The influence factors on the tubing column geometry, the fluid properties and particle properties were investigated by the indoor erosion experiments and numerical simulation respectively. Five different erosion models were applied to predict the erosion rate. The Generic model was selected to calculate the influencing value by a range of parameters after comparing the predicted results with the experimental data. The results indicated that the sand production rate, the gas production rate and the production pressure played a crucial role on the tubing column erosion. The error of Generic model is less than 20%. The product of the quadratic power of daily gas production, the negative quadratic power of production pressure and the first power of sand production rate was directly proportional to the erosion rate of tubing column. The sequence of the maximum erosion rate on different sites from high to low was obtained: No-Go Landing Nipple, Safety Valve, integral Y-type wellhead. The erosion effect on Y-type wellhead should be considered emphatically considering the long-term operation. The chart of Critical Erosion Coefficient (C value) was established according to the design criterion of API RP 14E, which is suitable for gas storage production channel. The reasonable C value should be set as 180.0 to ensure the gas storage to meet the service life. Meanwhile, the recommendatory C value range was set between 175.0 and 200.0 for considering the maximum productivity of gas storage. The research results provided a key guidance for judging the service safety of injection-production channel in gas storage.