Average Size Distribution Research Articles

Numerical simulation of diesel particulate filter performance optimization through pore structure analysis

Based on the theory of spherical filled bed, the internal porous media filter wall of the Diesel Particle Filter (DPF) is assumed to fill the filter wall of the unit cell. Since particle trapping by DPF is a dynamic process, the particle deposition characteristics inside DPF are simulated by numerical simulation in this paper. The influence of macroscopic incoming flow parameters and microstructural parameters on DPF filtration performance is investigated, and then the optimization window that can improve DPF filtration performance is explored. The results show that increasing the exhaust temperature and incoming particle concentration leads to an increase in the filtration efficiency and pressure drop of DPF, while the higher the filtration velocity, the lower the filtration efficiency of DPF. In addition, the larger the porosity, the higher the filtration efficiency and pressure drop of DPF, while the increase in the average pore size and pore size distribution range leads to a decrease of the filtration performance of DPF. On this basis, evaluation indexes that can evaluate the filtration performance of DPF are proposed to provide a theoretical basis for optimizing the substrate parameters of DPF.

Gamma‐ray irradiation effect on microstructure and physical performances of porous silica

AbstractIn this paper, the gamma irradiation effect on the microstructure and physical performances of porous silica, including mechanical, thermal, and optical performances, are systematically investigated by using molecular dynamics and density‐functional theory‐based methods. The study of bond angle distribution, pair distribution function, coordination number distribution, and average ring size distribution show that, after gamma‐ray irradiation, the microstructure of porous silica is obviously modified. The tight packing of SiO2 tetrahedrons in the porous silica network is broken by gamma‐ray irradiation. Defects of three‐coordinated Si and non‐bridging oxygen are induced by gamma‐ray irradiation. Moreover, we find that the defects concentrations rapidly grow as gamma‐ray dose increases. The mechanical, thermal, and optical performances of porous silica are all seriously degenerated by gamma‐ray irradiation. Our results show that, for mechanical performance, Young's modulus, Bulk modulus, and Shear modulus first decrease and then keep stable as gamma‐ray dose increases, but the change of Poisson's ratio is slight. For thermal performance, the thermal conductivity decreases exponentially as gamma‐ray dose increases. For optical performance, light absorption coefficients increase exponentially and light transmittance drops as gamma‐ray dose increases in the working range (photon energy range around 3.5 eV) of inertial confinement fusion. Present work is expected to be valuable for studying the degradation mechanism of silicate materials under gamma radiation and developing gamma‐ray irradiation protection technology.

Study on characterization technology of porosity and fractal dimension of micro-arc oxidation coating

Abstract The porosity of the micro-arc oxidation coating of pure titanium was assessed through the utilization of Mercury intrusion porosimetry (MIP). The porosity values were subsequently adjusted by accounting for the proportion of coating volume, resulting in a more precise determination of the coating’s porosity. Additionally, the fractal dimension of the pore structure was determined through the application of a linear regression equation utilizing the Mercury intrusion data. The findings indicate that the observed numerical dispersion from image metohd is substantial, with a range of 34.9% between the minimum and maximum values. This suggests that the precision and validity of the porosity outcomes derived from this approach are inadequate; The MIP is capable of determining both the porosity, average pore size and pore size distribution of the sample, while also mitigating the impact of the matrix through test result correction, thereby yielding precise porosity values. Additionally, the results of the verification experiment demonstrate a positive correlation between the porosity alteration of the MIP and oxidation duration, thereby affirming the reliability of the test outcomes; Through the analysis of pressure, pore size, cumulative Mercury intrude volume, and incremental Mercury intrude volume data obtained from MIP, the fractal dimension of the coating’s pore structure then be determined. Research showed that as the oxidation time increases, the pore fractal dimension of the MAO coating gradually expands within a narrow range, from 2.57 and finally stabilized at 2.77, indicating a gradual increase in pore structure complexity.

Prospects of silver nanoparticles (AgNPs) synthesized by Justicia secunda aqueous extracts on diabetes and its related complications

The wide range of secondary metabolites in medicinal plant extracts are used to treat and manage various diseases worldwide but more recently plant-mediated bio-nanotechnology is rapidly generating great research interest. Herein, the in-vitro study of the antidiabetic, anti-inflammatory, antiglycation, and antioxidant potentials of silver nanoparticles (AgNPs) synthesized by Justicia secunda aqueous extracts was evaluated. The synthesized AgNPs was characterized by UV-visible spectrophotometer, Fourier transform infrared spectroscopy (FT-IR) and Scanning electron microscopy (SEM). The antioxidant activity was evaluated via reducing power, 2,2-diphenyl-1-picrylhydrazyl (DPPH), total antioxidant capacity (TAC) and nitric oxide scavenging assays; antidiabetic activity was evaluated with α-glucosidase and α-amylase inhibitory assays; antiglycation activity was evaluated using fructosamine inhibitory assay, and anti-inflammatory activity was performed using trypsin inhibitory and albumin denaturation assays. The AgNPs from all the plant parts showed good biological potentials investigated compared to the plant extracts however, the synthesized AgNPs using the leaf aqueous extract (AgNPs-JsL) showed a better antioxidant, antidiabetic, antiglycation, and anti-inflammatory potentials with an essential quality absorption band in the ultraviolet region of 410 nm and average size distribution of 50.47nm. In conclusion, all the parts of J. secunda showed substantial antidiabetic, antioxidant, antiglycation and anti-inflammatory potentials with high yield of various bioactive metabolites, however, the AgNPs-JsL was more potent followed by the flower, stem and roots extracts, respectively.

Extracting dialdehyde cellulose nanocrystals using choline chloride/urea-based deep eutectic solvents: A comparative study in NaIO4 pre-oxidation and synchronous oxidation

Dialdehyde cellulose nanocrystals (DCNC) are defined as C2 and C3 aldehyde nanocellulose, which can be used as raw materials for nanocellulose derivatization, owing to the high activity of aldehyde groups. Herein, a comparative study in NaIO4 pre-oxidation and synchronous oxidation is investigated for DCNC extraction via choline chloride (ChCl)/urea-based deep eutectic solvent (DES). Ring-liked DCNC with an average particle size of 118 ± 11 nm, a yield of 49.25 %, an aldehyde group content of 6.29 mmol/g, a crystallinity of 69 %, and rod-liked DCNC with an average particle size of 109 ± 9 nm, a yield of 39.40 %, an aldehyde group content of 3.14 mmol/g, a crystallinity of 75 % can be extracted via optimized DES treatment combined with pre-oxidation and synchronous oxidation, respectively. In addition, the average particle size, size distribution, and aldehyde group content of DCNC were involved. TEM, FTIR, XRD, and TGA results reveal the variation of microstructure, chemical structure, crystalline structure, and thermostability of two kinds of DCNC during extraction even though the obtained DCNC exhibiting different micromorphology, pre-oxidation, or synchronous oxidation during ChCl/urea-based DES treatment can be considered as an efficient approach for DCNC extraction.

Silver nanoparticles doped heavy metal oxide borate glasses: luminescence and spectroscopic investigations

The effects of silver nanoparticles (NPs) embedded with samarium (Sm3+) ions doped on luminescence intensity of borate glasses was fabricated and evaluated using a method that is conventionally known as melt quenching. XRD study proved material's amorphousness. TEM examination determines average nanoparticle size distribution. Vibrational and structural units determined by FTIR and Raman spectra. DTA thermograms identify Tg, To, and Tp. XPS allows one to identify chemical shifts in addition to binding energies. Localized surface plasmon resonance (LSPR) band that has been identified is located at around 400 nm. It is a hypersensitive transition and enhancement of PL intensity due to the energy transfer from AgNPs to Sm3+ ions. A high-intensity emission peak can be seen at 599 nm (orange red), which is attributed to the electric dipole transition 4G5/26H7/2 of Sm3+ ions.The PL intensity non-linearity should be affected by the silver ion concentration. This happens because the energy is being transferred reverse, from the Sm3+ ions to the AgNPs, causing the PL intensity to oscillate in an anisotropic fashion. Analysis of the CIE diagram of glass system with Sm3+ ions suggests that it may be useful as a red luminous glass matrix in various photonic device implementations.

Influence of hydrocolloids and natural emulsifier in the physical stability of UHT oat beverage.

This study aimed to improve the physical stability of ultra-high temperature (UHT) oat beverage by adding hydrophilic colloids (guar gum [GG] and xanthan gum [XG]) and a natural emulsifier (soluble soybean polysaccharide [SSPS]). The stability of the oat beverage was characterized by particle size, zeta potential, rheological properties, Fourier-transform infrared (FTIR) spectroscopy, backscattered light intensity (ΔBS), and microstructure. The results indicated that XG reduced the average particle size and size distribution of the beverage, indicating that XG could prevent particle aggregation. GG increases the apparent viscosity of the oat beverage without affecting the zeta potential. When SSPS was added to the oat beverage, it increased the absolute value of the zeta potential and the infrared absorption peak intensity, while the average particle size and backscattered light intensity (ΔBS) decreased, resulting in a more uniform microstructure. The zeta potential reached a maximum value of 32.12 when GG, XG, and SSPS were combined, indicating that the physical stability of the oat beverage was effectively improved when all three were present simultaneously. This study may provide some suggestions for the industrial production of low-viscosity cereal beverages with good stability.

Formulation and optimization of aceclofenac loaded hyaluronic-oleic acid based micellar gel for the management of osteoarthritis

Aceclofenac is a non-steroidal anti-inflammatory drug used to manage osteoarthritis. However, its limited solubility, short half-life, and gastrointestinal side effects on chronic use limit its delivery via the oral route. This study used hyaluronic acid tailored with oleic acid via esterification to formulate micelles for aceclofenac topical delivery. The prepared micelles were characterized for average particle size, size distribution, surface charge, drug loading, entrapment efficiency, and surface morphology. The drug loading, entrapment efficiency, mean particle size, and zeta potential of micelles were 8.21 ± 0.3%, 81.25 ± 2.98%, 245.93 ± 7.68 nm, and −17.6 ± 1.95 mV, respectively. The prepared micelles were found to be spherical. The micelles were further loaded in chitosan gel and evaluated for drug release, skin permeation, and deposition. The hydrogel showed shear thinning behavior, sustained drug release, enhanced skin permeation, and deposition of aceclofenac. Further, the pharmacodynamic study revealed a significant reduction in pain and inflammatory response with an improved radiological and histopathological condition in the animal models. These results show the potential of hyaluronic acid oleic acid conjugate micellar gel as a promising carrier to deliver the poorly soluble small molecules like aceclofenac topically to manage the inflammatory condition.

Advanced Ag nanoparticles for the catalyzation of glyoxylic acid oxidation in through-holes electroless copper metallization

Advanced Ag nanoparticles (Ag NPs) were prepared by wet chemical oxidation–reduction method, using mainly the tannic acid as reducing agent and carboxymethylcellulose sodium as stabilizer. The prepared Ag NPs uniformly disperse and are stable for more than one month without agglomeration. The studies of transmission electron microscopy (TEM) and ultraviolet–visible (UV–vis) absorption spectroscopy indicate that the Ag NPs are in homogeneous sphere with only 4.4 nm average size and narrow particle size distribution. Electrochemical measurements reveal that the Ag NPs behave excellent catalytic activity for electroless copper plating using glyoxylic acid as reducing agent. In situ fourier transform infrared (in situ FTIR) spectroscopic analysis combined with density functional theory (DFT) calculation illustrate that the molecular oxidation of glyoxylic acid catalyzed by Ag NPs is as the following routes: glyoxylic acid molecule first is adsorbed on Ag atoms with carboxyl oxygen terminal, then hydrolyzed to diol anionic intermediate, and last oxidized to oxalic acid. Time-resolved in situ FTIR spectroscopy further reveals the real-time reactions of electroless copper plating as follows: glyoxylic acid is continuously oxidized to oxalic acid and releases electrons at the active catalyzing spots of Ag NPs, and Cu(II) coordination ions are in situ reduced by the electrons. Based on the excellent catalytic activity, the advanced Ag NPs can replace the expensive Pd colloids catalyst and successfully apply in through-holes metallization of printed circuit board (PCB) by electroless copper plating.

The plasmonic behaviours of gold nanoparticles with different thiol (n = 6, 10, 12) capping agents

The intense absorbance and scattering of incident light at the surface plasmon resonance wavelength of gold nanoparticles (AuNPs) is of paramount importance in its various and diverse applications. Being governed by their morphologies and surface chemistry, the optical property of AuNPs can be tuned to suit variety of applications by careful and systematic engineering of the particle surface. Among other variables, the nature of the ligands or capping agents employed and their concentrations play vital roles. Three different alkanethiols, namely 1-dodecanethiol (DDT), 1-decanethiol (DT) and 1-hexanethiol (HT) were investigated as capping agents in different concentration of gold/thiol ([Au]/[Thiol]) ratios of 7:1, 5:1, 3:1, 1:1, 1:3 and 1:5. First, the AuNPs with average particle sizes of 2 nm and characterised by 1H NMR, UV–visible, and TEM. The 1H NMR confirmed the capping of gold nanoparticles by the thiol. The TEM image confirmed the monodispersity of the nanoparticles with average size distributions of 2.4 nm, and plasmon absorption wavelength peaks at 505 nm was confirmed by the UV. There were variations in the values of the plasmonic peaks with the nature and concentrations of the capping agents.

Green synthesis of silver nanoparticles mediated Diospyros kaki L. (Persimmon): determination of chemical composition and evaluation of their antimicrobials and anticancer activities.

The eco-friendly synthesis of metallic nanoparticles (MNPs) using biological materials is an encouraging and innovativeness approach to nanotechnology. Among other synthesizing methods, biological methods are chosen because of their high efficiency and purity in many aspects. In this work, using the aqueous extract obtained from the green leaves of the D. kaki L. (DK); silver nanoparticles were synthesized in a short time and simply with an eco-friendly approach. The properties of the synthesized silver nanoparticles (AgNPs) were characterized using various techniques and measurements. In the characterization data of AgNPs, Maximum absorbance at 453.34nm wavelengths, the average size distribution of 27.12nm, the surface charge of -22.4mV, and spherical appearance were observed. LC-ESI-MS/MS analysis was used to assess the compound composition of D. kaki leaf extract. The chemical profiling of the crude extract of D. kaki leaves revealed the presence of a variety of phytochemicals, predominantly phenolics, resulting in the identification of five major high-feature compounds: two major phenolic acids (Chlorogenic acid and Cynarin), and tree flavonol glucosides (hyperoside, quercetin-3-glucoside, and quercetin-3- D-xyloside). The components with the highest concentrations were cynarin, chlorogenic acid, quercetin-3- D-xyloside, hyperoside, and quercetin-3-glucoside, respectively. Antimicrobial results were determined by a MIC assay. The biosynthesized AgNPs exhibited strong antibacterial activity against the human and food pathogen Gram (+ and -) bacteria and good antifungal activity against pathogenic yeast. It was determined that 0.03-0.050μg/mL concentrations ranges of DK-AgNPs were growth suppressive concentrations on all pathogen microorganisms. The MTT technique was used to study the cytotoxic effects of produced AgNPs on cancer cell lines (Glioblastoma (U118), Human Colorectal Adenocarcinoma (Caco-2), Human Ovarian Sarcoma (Skov-3) cancer cell lines, and Human Dermal Fibroblast (HDF) healthy cell line). It has been observed that they have a suppressive effect on the proliferation of cancerous cell lines. After 48h of treatment with Ag-NPs, the DK-AgNPs were found to be extremely cytotoxic to the CaCo-2 cell line, inhibiting cell viability by up to 59.49% at a concentration of 50gmL-1. It was found that the viability was inversely related to the DK-AgNP concentration. The biosynthesized AgNPs had dose-dependent anticancer efficacy. Because of the high concentration of bioactive chemicals in Diospyros kaki, it may be employed as a biological resource in medicinal applications. DK-AgNPs were shown to be an effective antibacterial agent as well as a prospective anticancer agent. The results provide a potential approach for the biogenic production of DK-AgNPs utilizing D. kaki aqueous leaf extract.

Green synthesis of chitosan/polyacrylic acid/graphitic carbon nitride nanocarrier as a potential pH-sensitive system for curcumin delivery to MCF-7 breast cancer cells

A novel pH-sensitive nanocarrier containing chitosan (CS), polyacrylic acid (PAA), and graphitic carbon nitride (g-C3N4) was designed via water/oil/water (W/O/W) emulsification to administer curcumin (CUR) drug. g-C3N4 nanosheets with a high surface area and porous structure were produced via simple one-step pyrolysis process using thiourea as precursor, and incorporated into CS/PAA hydrogel. X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR) were used to assess the crystalline structure of the nanocarrier and the interactions between its components, respectively. Scanning electron microscopy (SEM) images revealed a spherical structure and confirmed the g-C3N4 impregnation into the CS/PAA matrix. Zeta potential and dynamic light scattering (DLS) provided information about the surface charge and average size distribution. High CUR loading and entrapment efficiencies were obtained, which were further improved upon addition of g-C3N4. The release kinetics of drug-loaded CS/PAA/g-C3N4 nanocomposites were investigated at pH = 5.4 and pH = 7.4, and the results showed an excellent controlled pH-sensitive release profile. Cell apoptosis and in vitro cytotoxicity were investigated using flow cytometry and MTT analyses. CS/PAA/g-C3N4/CUR resulted in the highest rate of apoptosis in MCF-7 breast cancer cells, demonstrating the excellent nanocomposite efficacy in eliminating cancerous cells. CS/PAA hydrogel coated with g-C3N4 shows great potential for pH-sensitive controlled drug release.

Green synthesis of ZnO nanoparticles using marine brown algae (Cystoseira) extract comprising sol–gel, and combustion techniques based on dye-sensitized solar cells application

The ZnO nanoparticles were synthesized using marine brown algae (Cystoseira) extract and calcination. For comparison, combustion, and sol–gel methods were employed to synthesize nanoparticles to use as material in dye-sensitized solar cells (DSSCs) photoanode. The produced nanoparticles were characterized using structural and morphological studies by FTIR, SEM, and XRD experiments, respectively. The results revealed that the net hexagonal crystal structure was achieved with a crystal size of less than 100 nm, good purity, spherical shape, and a suitable dimension for fabricating DSSCs. They exhibit enhanced properties due to the variation in their characteristics such as average size, size distribution, and morphology. The ZnO nanoparticles were used to fabricate the DSSCs by the doctor blade method, and the efficacy of each cell was evaluated using voltage–current measurement. The results were in good agreement with the characteristic curve of the commercialized DSSC. The best performance for the fabricated DSSCs was achieved using green synthesized ZnO nanoparticles, because of the influence of their morphology such as smaller crystal size, more grain boundaries, and bigger surface area. The cell’s solar-to-electricity conversion efficiency, short-circuit current, open-circuit voltage, and fill factor were measured as ∼1.13%, 3.8[Formula: see text]mA/cm2, 620[Formula: see text]mV, and 54.3%, respectively. The enhanced photovoltaic properties were ascribed to the flower-like morphological structures of the ZnO nanoparticles prepared using the green synthesis method.

Controlling the Molar Ratios of Cation to Anion of Precursors for High Performance Capacitive Properties of MnO2 Hybridized Carbon-Based Materials Electrode

Controlling the cation to anion (Mn2+/MnO4−) molar ratios of the precursors was used to obtain a highly performance capacitive properties of nanostructural MnO2 hybridized carbon-based materials on nickel foam (NF) through successive ionic layer adsorption and reaction technology. SEM, XRD, BET, and XPS analyses are utilized to investigate the influence of cation/anion molar ratios of precursors on the as-obtained MnO2 electrode materials. At a lower molar ratio of cation/anion of 1, the prepared manganese oxide deposited on the NF with obvious δ-MnO2 phase. The average pore size distribution of BET analysis of the as-obtained δ-MnO2 is about 4.6 nm, the specific surface area is 155.7 m2 g−1, exhibiting a mesoporous structure. However, when the molar ratio of cation/anion is higher than 5, the deposited film produced by the reaction exhibits a γ-MnO2 crystal phase. The capacitance of δ-MnO2/NF electrode is 280 F g−1 at 1 A g−1 in a 1 M Na2SO4 aqueous electrolyte solution. In addition, reduced graphene oxide (rGO) mixed with multi-wall carbon nanotube (MWCNT) was added to synthesize γ-MnO2/rGO-MWCNT/NF electrode, which has a high capacitance of 377.4 F g−1 under the charge/discharge current density at 1 A g−1.

Structural and magnetic characterization of Co2+ substituted Ni-Zn ferrite nanoparticles synthesized by refluxing co-precipitation and their potential application as gas sensors

This work investigates the effect of Co2+ content on the structural, magnetic, and gas sensing properties of Ni0.3Zn0.7-xCoxFe2O4 (x=0.00, 0.05, 0.15, 0.25, 0.35) nanoferrites synthesized by refluxing co-precipitates of metal chlorides. X-ray diffraction and electron microscopy were used to study the structure and morphological aspects of the materials. X-ray diffraction (XRD) patterns revealed single-phase nanomaterial with shrinking lattice constants from 8.41 to 8.38 Å with increasing Co2+ content. The crystallite sizes varied slightly between 9.95 and 10.06 nm. The vibrating sample magnetometer (VSM) was used to extract information of the magnetization of the materials at room temperature. Saturation magnetization increased from 39.5 to 48.5 emu/g from x = 0 to 0.25 and dropped at x = 0.35 to 46.2 emu/g. Furthermore, the coercivity, effective anisotropy constant and remnant magnetization increased from 170 to 400 Oe, 696 to 1925 erg/Oe, and 1.15 to 2.72 emu/g respectively. A distinct correlation between the inverse initial magnetic susceptibility and unit cell volume of the materials was found. Room temperature 57Fe Mössbauer spectra revealed a magnetic transition from paramagnetic to ordered magnetic phase with increased Co2+ content. Except for sample with x = 0 and 0.15, where suspected co-existence of Fe3+ and Fe2+ was observed Fe3+ ions were observed. Zn2+ ions were found to largely occupy the B sites. Specific surface area and the average pore size distribution increased from 61 – 85 m2 g−1 and 22 – 25 nm respectively, with the addition of Co2+ content. The composition x= 0 showed exceptional response to propanol suggesting good suitability for sensor fabrication. All samples revealed the selectivity preferences in the order of propanol > ethanol > methanol.

Control of pressurized microbubble generation by multi-channel membranes: Experiments and modeling

Microbubbles have been attracting a lot of attention in the fields of chemical and petrochemical engineering, environmental protection, medicine, and aquaculture etc. Herein, a controlled pressurized microbubble generation system is developed. Numerous microbubbles are generated under certain of pressure by multi-channel ceramic membranes in a surfactant-free system consisting of dispersed gaseous and continuous aqueous phases. The average diameter and size distribution of the microbubbles are significantly affected by the membrane pore size, membrane area, liquid viscosity, pressure and gas-liquid flow ratio. A mathematical model about the average diameter of microbubbles is established for the first time by directly introducing the membrane parameters including the membrane area and membrane pore size, and the error of the as-established model is less than 10%. More importantly, the model can be used to predict the optimal membrane pore size and membrane area under different operating conditions under the premise of achieving the expected bubble size. The work will aid the understanding and development of microbubble generation with high performance.

Response Surface Optimization of Electro-Spun Polyvinyl Alcohol Nano-Fiber Membrane Process Parameters and its Characterization

An empirical exploration into the effects of time duration, voltage supply, concentration and flow rate on the membrane average fiber diameter and surface pore size distribution were done using response surface methodology (RSM) based on central compact design (CCD). The average fiber diameter and average surface pore diameter of the membrane (i.e. 110 nm and 130 nm, respectively) were obtained at optimum input parameters of 45 min, 10 wt. %, 12 kV and 1.0 mL/h for time duration, concentration, voltage supply, and flow rate, respectively. The optimization study shows that the predicted versus actual values of both membrane fiber diameter and surface pore diameter are at R2 = 0.96. In addition, the effect of glutaraldehyde on membrane crosslinking was also assessed for further studies. The results from FESEM images of the fabricated PVA nanofiber membranes using the optimized parameters revealed that the membranes showed smooth morphological structures without formation of beads. The thermo gravimetric analysis (TGA) results displayed an improvement in thermal stability after membrane crosslinking. From this study we have observed that the membrane average fiber diameter and surface pore diameter can be controlled by varying the electro-spinning parameters and can be utilized for wastewater treatment application.

Genesis of New Particle Formation Events in a Semi-Urban Location in Eastern Himalayan Foothills

New particle formation (NPF) events identified using scanning mobility particle sizer (SMPS) measurements, their subsequent growth and other characteristics over Dibrugarh, a semi-urban location in the eastern Himalayan foothills (EHF), during November–December 2016 are presented. The mean total number concentration of ultrafine aerosols was found to be high during morning and evening rush hours. The NPF occurrence frequency was found to be 14%. The temporal evolution of the hourly average aerosol number size distribution revealed that the nucleation burst occurred at a lower size spectrum, supporting the existence of NPF burst events. It continued to grow through coagulation loss and condensation sink with an average growth rate of 17.16 ± 12.29 nm/hr. The satellite-based observations showed a high concentration of the NPF precursors NO2, SO2, and HCHO during the NPF days. The backward air mass trajectories confirmed that the sources of emissions were confined within an area of radius ~100 km surrounding the observation site. These locally generated precursors and their associated photochemistry could be a probable reason for NPF occurrence at the study site.

Effect of different extraction methods on antioxidant properties and encapsulation efficiency of anthocyanin of pomegranate peel.

This study aimed to measure the efficiency, total anthocyanin content (TAC), and total phenol content (TPC) of pomegranate peel powder (PPP) extract from different extractions. Also, the characteristics of the nanoencapsulated extracts with maltodextrin (MD)/Lepidium perfoliatum (Qodume Shahri) seed gum were investigated. The highest and lowest extraction efficiency was related to solvent ethanol-water extraction (SEWE) (76.35%) and solvent ethanol extraction (SEE) (25.73%), respectively. Extracts obtained from microwave extraction (ME) and ultrasound extraction (UE) methods had the highest and lowest values of TAC (4.00-0.35) (mg C3G/g PPP) and TPC (702.13-232.58) (mg GAE/100 g sample), respectively. Peak 3213 in FT-IR indicates the O-H bond, which showed the highest content of phenolic compounds in the extract obtained from ME compared with SEE, SEWE, and UE. The nanoencapsulated extracts from SEE, SEE, and UE had the lowest particle size of peak 1, particle distribution in peak 1, and average particle size distribution compared with other extractions, respectively. The highest encapsulation efficiency of anthocyanin (EEA) and encapsulation efficiency of phenol (EEP) were related to UE (96.15%) and SEWE (86.57%), respectively. The EEP and EEA of SEE were not significantly different from ME and SEWE, respectively. On the other hand, the type and amount of extractive compounds in the extract have a great impact on the efficiency of nanoencapsulation and the average size distribution of nanoencapsulated particles. As a result, PPP extract is rich in antioxidant compounds, which can be determined by carefully examining the appropriate method of extraction and preservation of the extracted compounds.

Physicochemical Properties and Environmental Effects of Suspended Sediment Particles in the Largest Freshwater Lake, China

Suspended sediment particles (SSPs) act as a potential source of and sink for aquatic pollution. This study sampled six sites in Poyang Lake in August and November 2019. Changes in the physicochemical properties of SSPs were analyzed using scanning electron microscope energy-dispersive spectrometry (SEM-EDS). The results showed that SSPs consisted mainly of clay and chalk, with an average content of 39.71% and 57.52%, respectively. The average particle size distribution of SSPs in the study area ranged from 5.54 to 15.97 μm and the spatial distribution pattern showed the north lake area (I) > west lake area (II) > east lake area (III). The angle (K) of morphological indicators varied widely, with coefficients of variation between 0.25 and 1.23. Water-flow velocity was negatively correlated with SSP size, while suspended-solid concentration was positively correlated with SSP surface roughness. Morphological parameters, chemical composition, and correlation between each SSP form were analyzed to identify morphological distribution characteristics. Linear regression equations estimated endogenous phosphorus load in zones I, II, and III as 1027.202 mg/kg, 1265.343 mg/kg, and 1013.111 mg/kg respectively. Therefore, we conclude that the morphological differences in particulate matter, the interaction between chemical fractions, and the aqueous environment affecting the distribution of phosphorus fugitive forms, may contribute to endogenous lake pollution. These results are essential for revealing the intrinsic relationship between SSP physicochemical properties and lake eutrophication and studying other water–sediment interface processes of lake pollutants.