Particle Concentration Research Articles

Performances of two-stage electrostatic precipitator with different types of discharge electrodes of unipolar electrostatic agglomerator

Current-voltage characteristics of electrostatic agglomerator with three types of discharge electrodes, operating as the first stage of a two-stage electrostatic precipitator, and the effects of its operating parameter on the removal efficiency of this system for PM10 particles have been investigated. The results shown that the removal efficiency of the system of this specific design only weakly depends on the supply voltage of the AC kinematic electrostatic agglomerator in the supply voltage range of 18–26 kV. A synergistic effect between the operation of electrostatic agglomerator and electrostatic precipitator was obtained. By this effect, the removal efficiency of the whole system, i.e., the electrostatic agglomerator and electrostatic precipitator operating simultaneously, is higher than that determined as the combination of the removal efficiencies obtained for both of these stages operating alone. The effect of synergy results from the agglomeration of fly ash particles in the electrostatic agglomerator stage that decreases the concentration of small particles and increases their removal efficiency by electrostatic precipitator.

Mechanism of Improving Etching Selectivity for E-Beam Resist AR-N 7520 in the Formation of Photonic Silicon Structures

The selectivity of the reactive ion etching of silicon using a negative electron resist AR-N 7520 mask was investigated. The selectivity dependencies on the fraction of SF6 in the feeding gas and bias voltage were obtained. To understand the kinetics of passivation film formation and etching, the type and concentration of neutral particles were evaluated and identified using plasma optical emission spectroscopy. Electron temperature and electron density were measured by the Langmuir probe method to interpret the optical emission spectroscopy data. A high etching selectivity of 8.0 ± 1.8 was obtained for the etching process. The optimum electron beam exposure dose for defining the mask was 8200 pC/m at 30 keV.

MβCD inhibits SFTSV entry by disrupting lipid raft structure of the host cells

Severe fever with thrombocytopenia syndrome virus (SFTSV), recently named as Dabie bandavirus, belongs to the family Phenuiviridae of the order Bunyavirales, is a newly-identified bunyavirus with a case fatality rate of up to 30%, posing a serious threat to public health. Lipid rafts on plasm membranes are important for the entry of enveloped viruses; however, the role of lipid rafts in bunyavirus entry remains unclear. In this study, we found that methyl-beta-cyclodextrin (MβCD), a drug that disrupts cholesterol in lipid rafts of cell membranes, inhibits SFTSV infection. Additionally, there is a back-complementary effect of SFTSV infection upon the addition of cholesterol. Moreover, the concentration of SFTSV particles in lipid rafts during entry directly indicated the role of lipid rafts as a gateway, whereas MβCD could inhibit SFTSV entry by affecting the structure of lipid rafts. In an in vivo study, MβCD also reduced the susceptibility of mice to SFTSV infection. Our results suggest that SFTSV can interact with Talin1 proteins on lipid rafts to enter host cells by endocytosis of lipid rafts and reveal the potential therapeutic value of MβCD for SFTSV infection.

Volcanic ash in the water column: Cellular, physiological and anatomical implications for the gastropod suspension-feeder Crepipatella peruviana (Lamarck, 1822)

The influx of volcanic ash into seawater alters particle composition with implications for the cellular, physiological and anatomical response of suspension-feeding organisms. Adult females of Crepipatella peruviana were exposed to three diets consisting of a fixed concentration of 50,000 cells ml−1 of the microalga Isochrysis galbana plus different concentrations of ash particles (30, 90 and 150 mg L−1). The objective was to determine the cellular, physiological and anatomical responses. Mortality increased with ash concentrations, while feeding and respiration rates, tissue weight, and condition index decreased. The gills showed severe degradation of cilia and the presence of large mucous aggregates of cilia and ash. An increase in ash resulted in decreased lipid peroxidation and protein carbonyls, but increased total antioxidant capacity and phenols. Thus, volcanic ash particles may exert a high impact at both cellular and physiological levels for C. peruviana, where inhibition of gill function reduces the ability to acquire food.

Non-linear filtration model with splitting front

We consider filtration of a suspension in a homogeneous porous medium which is described by a macroscopic 1-D model including the mass exchange equation and the kinetic equation for deposit growth. The standard model assumes that suspended particles move at the same speed as the carrier fluid. However, in some experiments, a lag between the front boundary of suspended particles and the front of the carrier fluid was observed. This article proposes a modification of the standard model that provides a description of the separation between the fluid front and the particle front. For this purpose, a non-smooth non-linear function depending on the concentration of the suspension is introduced into the deposit growth equation. In case of a non-smooth suspension function, the concentration of suspended particles at the front decreases to zero in a finite time. At this moment the united front splits into the front of pure injected water and the front of suspended and retained particles. The particle front moves slower than the pure water front. In case of a linear filtration function (Langmuir coefficient), an exact solution is constructed in a closed form. For the filtration problem with a suspension function in the form of a square root, explicit analytical formulae are obtained. In case of a non-smooth filtration function, the filtration time is finite. The curvilinear boundary separates the filtration domain, where concentrations increase with time, from the stabilization domain, where the concentrations of suspended and retained particles have reached their limits. The limit speeds of the stabilization border and of the particle front coincide.

Synergistic Role of the AuAg-Fe3O4 Nanoenzyme for Ultrasensitive Immunoassay of Dengue Virus.

A combination of magnetic and noble metal nanoparticles (NPs) has recently emerged as a potential substance for rapid and sensitive immunosorbent assays. However, to make the assay an alternative method for Enzyme-linked immunosorbent assay, the individual role of each nanoparticle must be explored properly. In this work, an immunoassay has been proposed using two antibody-conjugated iron oxide nanoparticles (Fe3O4NPs) and gold-silver bimetallic nanoparticles (AuAgNPs) to enhance the sensitivity of virus detection by colorimetric TMB/H2O2 signal amplification. A synergistic effect is monitored between Fe3O4NPs and AuAgNPs, which is explored for colorimetric virus detection. The sensor exploits the synergistic effect between the nanoparticles to successfully detect a wide range of dengue virus-like particle (DENV-LP) concentrations ranging from 10 to 100 pg/mL with a detection limit of up to 2.6 fg/mL. In the presence of a target DENV-LP, a sandwich-like structure is formed, which restricts the electron transfer and the associated synergistic effect between the nanoparticles, restricting the TMB oxidation process. Therefore, the synergistic effect is the key to the present work, which accounts for the enhanced rate of the enzymatic reaction on TMB and makes the current method of virus detection more sensitive and reliable compared to the others.

Study on the Effectiveness of a Copper Electrostatic Filtration System "Aerok 1.0" for Air Disinfection.

Bioaerosols can represent a danger to health. During SARS-CoV-2 pandemic, portable devices were used in different environments and considered a valuable prevention tool. This study has evaluated the effectiveness of the air treatment device "AEROK 1.0®" in reducing microbial, particulate, and pollen airborne contamination indoors, during normal activity. In an administrative room, airborne microbial contamination was measured using active (DUOSAS 360 and MD8) and passive sampling; a particle counter was used to evaluate particle concentrations; a Hirst-type pollen trap was used to assess airborne pollen and Alternaria spores. Statistical analysis was performed using SPSS 26.0; p values < 0.05 were considered statistically significant. The airborne bacterial contamination assessed by the two different samplers decreased by 56% and 69%, respectively. The airborne bacterial contamination assessed by passive sampling decreased by 44%. For fungi, the reduction was 39% by active sampling. Airborne particles (diameters ≥ 1.0, 2.0 μm) and the ratio of indoor/outdoor concentrations of total pollen and Alternaria spp. spores significantly decreased. The results highlight the effectiveness of AEROK 1.0® in reducing airborne contamination. The approach carried out represents a contribution to the definition of a standardized model for evaluating the effectiveness of devices to be used for air disinfection.

Effects of tire particles and associated-chemicals on the Pacific oyster (Magallana gigas) physiology, reproduction and next-generation

By 2040, tire particles (TP) are expected to dominate marine plastic contamination, raising concerns about their effects on marine animals. This study employed a multidisciplinary and multigenerational approach on the Pacific oyster Magallana gigas to investigate the effects of TP and their leachates (LEA). Effects were analyzed at the individual scale, from cellular, molecular, and microbiota changes to reproductive outputs and offspring performance. Microbiota characterization revealed potential dysbiosis in oysters treated with high concentration of both TP and LEA. RNA-seq analyses highlighted the activation of energy metabolism and stress responses in the LEA treatment. Additionally, transcriptional changes in oocytes and the reduction of motile spermatozoa suggested potential effects on gamete quality. Notably, possible oyster resilience was pointed out by the lack of significant ecophysiological modifications in adults and impacts on the growth and reproductive outputs of the offspring. Overall, the implications of the observed oyster resilience under our experimental setting are discussed in relation to available toxicity data and within a comprehensive view of coastal ecosystems, where a higher diversity of plastic/rubber materials and harsher environmental conditions occur.

Assessing Inter-yarn Frictional Behavior of Jute Fabrics Impregnated with Corn Flour Particles-Based Shear Thickening Fluids

Recently naturally driven fabrics are gaining more attention to develop impact-resistive fabrics due to their cost-effectiveness and environment-friendly nature. The effectiveness of jute fabrics becomes more prominent when used with shear thickening fluids (STFs). The present study is focused on the assessment of inter-yarn frictional behavior of jute fabrics impregnated with natural corn flour particles-based STFs. The varying amount of corn flour particles of 10 and 13 µm were blended with deionized water, glycerol, and polyethylene glycol (PEG-400) to synthesize STFs. To the best of our knowledge, first time the stability and rheological performance of corn flour particles-based STFs under varying shear rates in different dispersion mediums have been investigated. The peak viscosity of STF consisting 50% particles (10 µm) in glycerol was found significantly higher compared to the STF consisting same size and concentration of particles with deionized water. The yarn pull-out test was conducted to evaluate the materials’ inter-yarn frictional resistance behavior. The maximum pulling force was observed for jute fabric impregnated with glycerol-based STF. Thus, the developed STFs can be vital for developing better impact-resistive fabrics.

Interaction of Micro- and Nanoplastics with Enzymes: The Case of Carbonic Anhydrase.

Microplastics (MPs) and nanoplastics (NPs) have emerged as significant environmental pollutants with potential detrimental effects on ecosystems and human health. Several studies indicate their interaction with enzymes; this topic represents a multifaceted research field encompassing several areas of interest from the toxicological and ecotoxicological impact of MPs and NPs on humans and wildlife to the biodegradation of plastics by microbial enzymes. This review aims to provide a critical analysis of the state-of-the-art knowledge of the interaction of MPs and NPs on the enzyme carbonic anhydrase (CA), providing recent insights, analyzing the knowledge gaps in the field, and drawing future perspectives of the research and its application. CA is a widespread and crucial enzyme in various organisms; it is critical for various physiological processes in animals, plants, and bacteria. It catalyzes the reversible hydration of CO2, which is essential for respiration, acid-base balance, pH homeostasis, ion transport, calcification, and photosynthesis. Studies demonstrate that MPs and NPs can inhibit CA activity with mechanisms including adsorption to the enzyme surface and subsequent conformational changes. In vitro and in silico studies highlight the role of electrostatic and hydrophobic interactions in these processes. In vivo studies present mixed results, which are influenced by factors like particle type, size, concentration, and organism type. Moreover, the potentiality of the esterase activity of CA for plastic degradation is discussed. The complexity of the interaction between CA and MPs/NPs underscores the need for further research to fully understand the ecological and health impacts of MPs and NPs on CA activity and expression and glimpses of the potentiality and perspectives in this field.

Methods for laboratory-generation and physico-chemical characterisation of tyre wear particles

Tyre wear particles are generated by the frictional forces between a tyre and the road during driving. Tyre wear represents one of the biggest sources of synthetic polymer-based material released into the environment, significantly contributing to microplastic pollution and the associated ecological consequences. However, the extent of tyre particle pollution is not fully understood, and research and understanding are hindered by a lack of described chemical compounds that meet all the criteria for an effective marker of tyre particles. The aims of this study were to develop a methodology for generating tyre particles using a pin-on-disc tribometer; and to distinguish the chemical components in the particles – using two-dimensional gas chromatography-mass spectrometry – to propose a suite of potential markers. The results show that the morphology of the tyre particles reflected that of particles generated in previous literature and during driving. Additionally, the suggested markers were common across the three tyre brands studied here, thus meeting one of the criteria for a successful marker. Future research into measuring the concentration of tyre particles in environmental samples is necessary to understand further their distribution, and assessing the contribution of tyre particles to non-exhaust emissions can inform on future engineering strategies to minimise their release

Impact of weathered and virgin polyethylene terephthalate (PET) micro- and nanoplastics on growth dynamics and the production of extracellular polymeric substances (EPS) of microalgae

The ever-increasing plastic waste accumulation in the marine environment necessitates a deeper understanding of microalgae interactions with micro- and nanoplastics (MNP), and the role of extracellular polymeric substances (EPS). EPS, known for its adhesive properties and produced as an algal stress response, may facilitate aggregation of both algae and MNPs, thereby impacting ecological and hydrodynamic processes such as the trophic transfer or vertical transport of MNPs. Moreover, gaining a deeper understanding of the impact of weathering processes on the potential toxicological effects of plastic particles, and the comparative significance of plastic-specific effects relative to those of naturally occurring particles such as kaolin clay, is imperative. Therefore, this study investigated the impact of fragmented, polydisperse virgin polyethylene terephthalate (PET, Daverage = 910 nm) and weathered PET (Daverage = 1700 nm) on the growth and the production of EPS of Rhodomonas salina. Algae were exposed to a range of low MNP concentrations (10, 100 and 1000 and 10,000 MNPs ml-1) for 11 days. A natural particle control (kaolin, Daverage = 1600 nm) was deployed to differentiate particle effects from plastic effects. It was observed that exposure to both weathered PET and virgin PET resulted in initially increased growth rates (7.80 % and 7.28 % respectively), followed by significant decreases in algae cell density (−30.1 % and −11.2 % respectively). Furthermore, exposure to weathered PET caused a simultaneous elevation in cellular EPS production (76.51 %). The effects of plastics were significantly larger than the effect of kaolin. Also, the observed effects were amplified by the weathering of the plastics. These observations underscore the interactions between particle type, age and concentration, and their distinct impacts on algae density and growth inhibition. The observations indicate a role for EPS as an algal protection mechanism, potentially affecting the environmental fate of MNP – microalgae aggregates.

Structure–property correlation assessment of LLDPE‐based biocomposites with Azadirachta Indica wood flour

AbstractThis research explores the development of new composite material by integrating Azadirachta Indica (AI) with LLDPE to create wood‐plastic composites using the rotational molding process. By examining various proportions of AI wood flour blended with LLDPE, we investigated their impact on mechanical and physical properties. Our tests elucidate a clear correlation between mechanical properties and composite morphologies. Despite identical molding conditions, higher wood particle concentrations reduced mechanical properties compared to lower concentrations. Remarkably, a 12% wood content emerges as optimal, yielding a tensile modulus of 3.69 MPa and a flexural modulus of 468.5 MPa, with an acceptable reduction of 11% density and 13% porosity versus pure LLDPE. Additionally, we observed declines in tensile strength, impact strength, and hardness by up to 23%, 62%, and 11%, respectively, compared to neat LLDPE. Natural fillers enhance aesthetics, making these materials ideal for consumer products like garden equipment and furniture accessories.

Dyslipidemias in multiple sclerosis

PurposeTo investigate the frequency of dyslipidemia phenotypes in multiple sclerosis and to assess the associations with lipoprotein particle size distributions. MethodsThis cross-sectional study included 203 healthy controls (HC), 221 relapsing-remitting MS (RRMS), and 126 progressive MS (PMS). A lipid profile with total cholesterol, high-density lipoprotein cholesterol (HDL-C), triglycerides, and apolipoprotein B levels were measured. Low density lipoprotein cholesterol (LDL-C), very low-density lipoprotein cholesterol, large buoyant LDL-C and small dense LDL-C were calculated using the Sampson-NIH equations method. Dyslipidemia phenotypes were categorized by their nonHDL-C and triglyceride values. The diameters and concentrations of triglyceride-rich lipoprotein particles (TRLP), LDL particles (LDLP), and HDL particles (HDLP) were measured with proton NMR lipoprotein profiling. Serum proprotein convertase subtilisin/kexin type 9 (PCSK9) levels were obtained using immunoassay. ResultsThe frequencies of normolipidemia, and various dyslipidemia phenotypes were similar in HC, RRMS, and PMS. The size of the TRLP, very large TRLP, large TRLP, and small LDLP concentrations had a decreasing pattern of HC>RR>PMS. The lowest tertile of EDSS was associated with higher concentrations of HDLP and small HDLP in PMS. PCSK9 was associated with concentration of HDL particles, primarily via its effects on the concentration of small HDL particles. ConclusionsThere were no differences in the frequency of dyslipidemias in MS compared to healthy controls. Higher HDLP concentrations are associated with lower disability in PMS.

Characterization of hybrid silicate materials based on ceramic glazes and waste London underground dust

In “London Underground” stations, a high concentration of dust particles containing organic and inorganic matter of varying chemical composition. “London underground dust” is created from train wheels and brakes grinding against steel tracks and collected in filtration systems. The experiment will focus on using “London Underground Dust” to colour the ceramic facing tiles intended for re-use in newly built London Underground stations. The phase composition, particle size distribution surface area, morphology, and thermal behavior of collected dust were studied by XRD, XRF, SEM-EDS, BET, heating microscopy, STA-MS, UV–VIS spectroscopy. The substrate tiles for glazing experiments were prepared from local London clay. The mixtures of glazes and collected or milled dust were sprayed on the substrate tile's surface, dried and finally fired at 1060 °C. The influence of used materials weight ratio and dust milling time were shown as crucial parameters to obtain optimal final glaze colour.

Correlating scatterer concentration and intensity threshold of random laser in niobium oxide particle colloids with dye solution

Our study examines how the concentration of scatterers affects the intensity threshold of random laser (RL) action in colloids made of niobium oxide particles and Rhodamine B dye. This is the first reported instance of RL action in niobium oxide. We kept the dye (gain medium) concentration constant and quantified how varying concentrations of niobium oxide particles (scatterers) affect the RL intensity threshold. Our findings indicate an inverse relationship between the concentration of niobium oxide particles and the RL threshold. Increasing the niobium oxide concentration from 0.32 mM to 2.50 mM decreased the RL threshold by up to 70 %, suggesting that higher scatterer densities lead to enhanced efficiency of the lasing process. We noticed that the RL intensity thresholds decrease concerning scatterer concentration, highlighting the significant impact of scatterer density on lasing efficiency. These results could provide a better comprehension of the mechanics of RL in disordered media and emphasize the essential role of scatterer density in determining RL efficiency. Our work deepens the understanding of RL dynamics and lays the groundwork for designing and optimizing colloidal RL systems for various applications such as imaging and optical sensing.

Analysis of the impact of exfoliated graphene oxide on the mechanical performance and in-plane fracture resistance of epoxy-based nanocomposite

Graphene oxide (GO) is a versatile material, derivative of graphene, and it has gained significant attention in the field of polymer nanocomposites due to its exceptional properties and unique structural features. These characteristics make it a successful secondary reinforcing agent for enhancing mechanical performance, fatigue resistance, and other various physical and thermal properties of nanocomposites. However, the low fracture toughness of nanocomposite has restricted the overall structural applications. In this research work, the epoxy nanocomposites were prepared with different weights of exfoliated graphene oxide (E-GO) nanoparticles by using a dual mixing probe ultra-sonication for homogeneous distribution and proper dispersion. A substantial enhancement in mechanical performance and fracture toughness of nanocomposite was observed. The good dispersion and interfacial adhesion among E-GO and epoxy matrix were investigated through the critical analysis of the fracture surfaces of the nanocomposite. The enhancement of mechanical performance of E-GO nanofiller-reinforced epoxy composite was observed superior at 1 wt. % of GO60 particle concentration. The maximum increment of mechanical properties such as tensile strength, flexural strength, and work of fracture were 40.763, 39.23, and 12.106 % respectively, whereas maximum tensile modulus and flexural modulus were 19.3724, 27.63 % at 1.5 wt. % of GO60 as compared to the neat composite. However, in the case of fracture toughness and energy, maximum improvement of 1.256 Mpa.m1/2 and 0.472 KJ/m2 respectively was observed at 1 wt. % of GO60. Such enhancement was primarily due to the bolstering of in-plane crack propagation resistance in the nanocomposites. Additionally, the highlight point in thermomechanical properties of the polymer nanocomposite is optimal storage modulus and damping factor such as 4066.75 MPa, and 0.46 respectively, for the GO60 at 1 wt.% nanocomposite. Moreover, GO60 at 1 wt.% demonstrates greater thermal stability, withstanding up to 50% material degradation at 413.65°C.

Study on the microstructure, mechanical and corrosion behaviors of 2A12 Al matrix composites containing B4C and 50% K2TiF6 flux

This study presents an innovative exploration into the development and characterization of boron carbide (B4C) reinforced aluminum (Al) metal matrix composites (AMMCs), specifically focusing on the 2A12 Al alloy. Utilizing a cutting-edge vacuum induction melting process, the research investigates the effects of varying B4C particle concentrations in conjunction with 50% K2TiF6 flux additions. This novel approach aims to enhance the microstructural integrity, mechanical properties, and corrosion resistance of the AMMCs. The research unveils a significant improvement in microhardness and tensile strength with the increase of B4C content. This enhancement is attributed to the efficient load transfer mechanism from the aluminum matrix to the B4C phase and the thermal expansion coefficient mismatch-induced dislocations. A critical finding of this study is the uniform distribution of B4C particles and the formation of a Ti-rich layer around these particles, facilitated by the K2TiF6 flux. This layer acts as a barrier, minimizing interfacial reactions. Electrochemical testing reveals that there is a slight decrease in corrosion resistance with increased B4C content. The outcomes of this research contribute to the field of metal matrix composites, offering a path forward for the application of B4C-reinforced AMMCs in demanding industrial environments where high strength, stiffness, and durability are critical. The study's findings open new avenues for advanced materials development in aerospace, automotive, and energy sectors.

Research on characteristics and influencing factors of road dust emission in a southern city in China.

One of the primary causes of urban atmospheric particulate matter, which is harmful to human health in addition to affecting air quality and atmospheric visibility, is road dust. This study used online monitoring equipment to examine the characteristics of road dust emissions, the effects of temperature, humidity, and wind speed on road dust, as well as the correlation between road and high-space particulate matter concentrations. A section of a real road in Jinhua City, South China, was chosen for the study. The findings demonstrate that the concentration of road dust particles has a very clear bimodal single-valley distribution throughout the day, peaking between 8:00 and 11:00 and 19:00 and 21:00 and troughing between 14:00 and 16:00. Throughout the year, there is a noticeable seasonal change in the concentration of road dust particles, with the highest concentration in the winter and the lowest in the summer. Simultaneously, it has been discovered that temperature and wind speed have the most effects on particle concentration. The concentration of road dust particles reduces with increasing temperature and wind speed. The particle concentrations of road particles and those from urban environmental monitoring stations have a strong correlation, although the trend in the former is not entirely consistent, and the changes in the former occur approximately 1 h after the changes in the latter.

The presence of nanoparticles in aqueous droplets containing plant-derived biopolymers plays a role in heterogeneous ice nucleation.

Organic matter can initiate heterogeneous ice nucleation in supercooled water droplets, thereby influencing atmospheric cloud glaciation. Predicting the ice nucleation ability of organic matter-containing cloud droplets is challenging due to the unknown mechanism for templating ice. Here, we observed the presence of nanoparticles in aqueous samples of known ice-nucleating biopolymers cellulose and lignin, as well as in newly identified ice-nucleating biopolymers xylan and laminarin. Using our drop Freezing Ice Nuclei Counter (FINC), we measured the median ice nucleation temperature (T50) of xylan and of laminarin droplets of 2 μl to be -14.2 and -20.0 °C, respectively. Next, we characterized these samples using nanoparticle tracking analysis, and we detected and quantified nanoparticles with mean diameters between 132 and 267nm. Xylan contained the largest nanoparticles and froze at higher temperatures. Xylan also dictated the freezing in a 1:1:1:1 mixture with cellulose, lignin, laminarin, and xylan. Filtration experiments down to 300 kDa with the xylan sample indicated that the presence of nanoparticles triggered freezing. Overall, only samples with mean diameters above 150nm froze above -20 °C. Furthermore, we determined the ice-active site densities normalized to particle concentrations, surface area, and mass of the nanoparticles to show that the samples' nucleation site densities are similar to sea spray aerosols and nanometer-sized dust. The identification and characterization of xylan and laminarin as nanometer-sized ice-nucleating substances expands the growing list of organic matter capable of impacting cloud formation and thus climate.