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Background: Health concerns about the exposure to genotoxic and carcinogenic agents in the air are particularly significant for outdoor workers in less developed countries. Aims: To investigate the association between personal exposure to a group of air pollutants and severity of DNA damage in outdoor workers from two Mexican cities. Methods: DNA damage (Comet assay) and personal exposure to volatile organic compounds, PM2.5, and ozone were investigated in 55 outdoor and indoor workers from México City and Puebla. Results: In México City, outdoor workers had greater DNA damage, reflected by a longer tail length, than indoor workers (median 46.8 v 30.1 μm), and a greater percentage of highly damaged cells (cells with tail length ⩾41 μm); in Puebla, outdoor and indoor workers had similar DNA damage. There were more alkali labile sites in outdoor than indoor workers. The DNA damage magnitude was positively correlated with PM2.5 and ozone exposure. Outdoor and indoor workers with ⩾60% of highly damaged cells (highly damaged workers) had significantly higher exposures to PM2.5, ozone, and some volatile organic compounds. The main factors associated with the highly damaged workers were ozone, PM2.5, and 1-ethyl-2-methyl benzene exposure. Conclusions: With this approach, the effects of some air pollutants could be correlated with biological endpoints from the Comet assay. It is suggested that the use of personal exposure assessment and biological endpoints evaluation could be an important tool to generate a more precise assessment of the associated potential health risks.

The Mu Us Sandy Land is a region characterized by wind-blown sand and soil erosion in northern China. To enhance the soil quality of this area, various organic materials were incorporated into the mixed soil at a volume ratio of 1:2 for feldspathic sandstone to sand. Culture was conducted in the field and under constant temperature conditions in laboratory culture chambers. Four treatments were established in the experiment, each calculated based on weight ratio and controlled (with no organic material added, CK); single application of straw (5% straw, P1); single application of biochar (5% biochar, P2); combined application of biochar and straw (5% biochar + 5% straw, P3). After 90 days of culture, soil samples were collected for analysis of various indicators such as soil aggregate particle size distribution, water stability of soil aggregates, mean weight diameter, mean geometric diameter, and fractal dimension using dry sieving and wet sieving methods. The objective is to establish a scientific basis and provide technical support for addressing the challenges associated with compound soil and implementing rational fertilization measures. The research results indicate that: (1) The quantity of aggregates > 0.25 mm under different treatments follows the order CK < P1 < P2 < P3, and the differences between treatments are significant (P < 0.05); (2) Soil water stability, mean weight diameter (MWD), mean geometric diameter (GMD), and fractal dimension of soil aggregates in compound soil with different organic material additions are superior to the control, and the effect of biochar on improving soil aggregates is better than that of corn straw. The combined application of both significantly improves the effect compared to single applications. In both culture modes, under wet sieving, the P3 treatment shows the highest MWD and GMD of soil aggregates, with an increase ranging from 3.45% to 85% and 4.55% to 38.46%, respectively, compared to other treatments. (3) The trend of fractal dimension among treatments is consistent: P3 < P2 < P1 < CK, and the differences between treatments are significant (P < 0.05). Moreover, there is a good negative correlation linear equation relationship between the fractal dimension (y) and WR > 0.25 (x) of compound soil, with a correlation coefficient of up to 0.9851. In conclusion, the incorporation of organic materials can effectively enhance the proportion of macroaggregates in compound soil consisting of Feldspathic sandstone and sand, thereby improving soil stability and erosion resistance. The optimal outcome is achieved through the combined application of biochar and straw. Indoor culture proves to be more effective than field culture, while wet sieving accurately reflects the structural characteristics of compound soil under both dry and wet sieving treatments.

Raindrop size distributions (RSD) of southwest (SW – June to September) and northeast (NE – October to December) monsoon heavy precipitation are measured with PARticle SIze and VELocity (PARSIVEL) disdrometer and Micro Rain Radar (MRR) deployed at Kadapa (14.47°N; 78.82°E), a semi-arid continental site in Andhra Pradesh, India. RSD characteristics stratified on the basis of rainrate showed that the mean values of raindrop concentration of small (medium) drops are less (more) in SW when compared with NE monsoon heavy precipitation. Gamma function applied to heavy precipitation events showed that the mean value of mass weighted mean diameter, Dm (normalized intercept parameter log10Nw) is higher (lower) in SW monsoon than NE monsoon. Stratiform and convective precipitating cloud fraction observed during SW and NE monsoons revealed that contribution of stratiform precipitation is predominant for the seasonal variation in raindrop size distribution. The coefficient and exponent values of the Z–R relations are higher in SW than NE monsoon in both stratiform and convective precipitation.

The research aimed to explore the influence of different land use manners on soil aggregate, and provide scientific basis for improving soil stability and production performance of consolidation and returning to field in hollow village of hilly area. After consolidation and returning to field in hollow village of hilly area of Chengcheng County, Shaanxi, 5 kinds of land use manners were set for 1-year plantation test, and they were corn （C treatment）, wheat （W treatment）, vegetable （V treatment）, medicinal material （M treatment） and control （no plantation: CK treatment）. Soil aggregate distribution, mean mass diameter（WMD）, geometric mean diameter（GMD）, aggregate failure rate（PAD）, unstable aggregate number（ELT）and fractal dimension（D） at 0-40 cm of soil layer were measured and analyzed by dry and wet sieving methods. The results showed that （i） soil aggregate number and size at 0-40 cm of soil layer by each treatment were all significantly better than CK treatment, and >0.25 mm of aggregate content by dry sieving method （DR0.25）and >0.25 mm of aggregate content by wet sieving method （WR0.25）at 0-40 cm of soil layer in each treatment showed declining trend with soil layer depth increased; （ii）MWD and GMD sequences of each treatment at 0-40 cm of soil layer by dry and wet sieving methods were both W treatment>C treatment>M treatment>V treatment>CK treatment, and C treatment was conducive to increasing large aggregate content of surface soil, while W treatment was conducive to increasing large aggregate content of lower soil; （iii）the analysis by wet sieving method showed that PAD and ELT at 0-40 cm of soil layer in each treatment both showed similar “Z” shape trend, and each treatment was significantly lower than CK;（iv）D sequence at 0-40 cm of soil layer in each treatment was C treatment0.25 mm of aggregate content at 0-40 cm of soil layer by dry and wet sieving methods, and they were respectively R2=0.74 and R2=0.67. Corn and wheat plantation after consolidation and returning to field in hollow village was conducive to improving large aggregate content at 0-40 cm of soil layer, increasing the stability of soil layer and improving soil structure.

\"A theoretical model is developed for the prediction of the mean-mass diameter of droplets produced by the fragmentation of liquid fuel sheet and film in a fuel-air explosive (FAE) device after the detonation of the central burster charge. This model does not contain arbitrarily assumed values for the instabilities as in presently available models. Also, a distribution model for the initial distribution of the droplet diameter, which depends on the design parameters of the FAE device, is presented. \"

The L-shaped pulsed sieve-plate column (LPSPC) was introduced by Akhgar et al. to improve the efficiency of horizontal columns. It combined vertical and horizontal columns to enhancing efficiency, reducing height and increasing capacity through suction forces at the connection point. Droplet size is crucial for hydrodynamics and mass transfer in extraction columns, affecting interfacial area and overall performance. The Sauter mean diameter (SMD) and drop size distribution (DSD) are key design parameters in LPSPCs. The behavior of SMD and DSD was investigated in an LPSPC for four chemical systems, including water-kerosene, 17% nitric acid-5% TBP/kerosene (v/v), 17% nitric acid-15% TBP/kerosene (v/v) and 17% nitric acid-30% TBP/kerosene (v/v). The influence of the operating parameters such as pulsation intensity and flow rate of dispersed and continuous phases on SMD and DSD were evaluated. Additionally, the effect of interfacial tension and the percentage of TBP in the dispersed phase on SMD were investigated. Using the experimental results, semi-empirical correlations were obtained for prediction of SMD, which proved to be in great agreement with the experimental data. The average absolute relative error (AARE) of these correlations was 6.95% and 8.29% for the horizontal and vertical sections, respectively. Furthermore, new correlations were presented for prediction of DSD based on the four models of distribution functions. The AARE values of α and β parameters for each of the normal, log-normal, Weibull, and gamma functions were about 3.40–9.60, 11.52–17.65, 2.62-16.00, and 29.09–38.93%, respectively. According to the results, normal, Weibull and log-normal models were acceptable, in order.

Due to the excellent heat transfer performance, spray cooling is widely used for heat removal of high-heat-flux electronic devices. In this study, the influence of spray characteristics on spray cooling heat transfer is tested experimentally, where both water and 4% ethanol-water mixture are used as the working fluid. The Sauter mean diameter and droplet number distributions are measured by the Particle/Droplet Imaging Analysis system, and the fluid volumetric flux distributions are measured by the self-designed Precision Mobile Experiment Bench. The results show that the heat transfer efficiency of the 4% ethanol-water mixture is superior to that of water. Especially, the critical heat flux is about twofold that of water for the Spray A nozzle. For a fixed nozzle, the Sauter mean diameter of the 4% ethanol-water mixture is smaller, while the fluid volumetric flux shows an increase under the same conditions. Small Sauter mean diameter and large fluid volumetric flux can induce more droplets to entrain bubbles. Then the mechanisms of improved spray cooling heat transfer are analyzed based on the spray characteristics measurement results. It is revealed that the Sauter mean diameter and mean fluid volumetric flux exert joint influence on the heat transfer efficiency, and the mean fluid volumetric flux has an obvious effect between different nozzles. Two dimensionless heat flux correlations are proposed for the single-phase and nucleate boiling regimes with mean absolute errors of 15.56% and 14.68%, respectively. Highlights Sauter mean diameter of 4 vol.% ethanol-water is smaller than water, but the fluid volumetric flux is higher than water. Small Sauter mean diameter and large fluid volumetric flux induce more droplets generating entrained bubbles, which can enhance the heat transfer performance. Fluid volumetric flux is predominant in improving heat transfer performance, especially in the nucleate boiling regime. Spray characteristics have an obvious influence on the critical heat flux. Dimensionless heat flux is correlated with characteristic numbers integrating Sauter mean diameter and fluid volumetric flux.

The paper investigates the geometry and droplet size distribution of a fuel spray produced by an injection system with air-assisted (pneumatic) atomizer. Two optical research methods, based on the processing of images obtained through shadow photography, were employed. The evolution of a pulsed spray was studied using a high-speed video camera with a macro lens. Droplet size distributions were studied using a camera equipped with a long-distance microscope and backlighting comprising a luminescent background screen and a pulse laser. The study was conducted for air-to-fuel mass flow rate ratios (ALR) of 1 and 0.16. The Sauter mean diameter for atomized droplets was 13 and 18 microns for the ratio values of 1.0 and 0.16, respectively.

The average radius of coal particles is an estimate of the diffusion path in the particle method for determining the diffusion coefficient. It is currently calculated using the arithmetic mean of coal particle sieved intervals. This calculation, however, ignores the coal particle size distribution, resulting in significant deviations when calculating the gas diffusion coefficient. An appropriate average radius calculation method should consider the particle size distribution and the physical essence of diffusion. To accomplish this, a series of methods for calculating the mean particle diameters and their physical significance were reviewed. Next, coal samples were sieved into three intervals, and gas diffusion tests and laser particle size distribution were conducted. Results show that coal particles are within the sieving interval, ranging from 42.01 to 76.18%. By solving the diffusion coefficients using four mean particle diameters based on particle size distribution and diffusive mass transfer, the difference between the arithmetic mean value and these diameters is up to 89.06%. D ¯ 5 , 3 and D ¯ 6 , 3 are preferred for the calculation of the average radius since they are compatible with coal particle shape and the physical meaning of diffusive mass transfer.

In order to meet the emission reduction targets set for the shipping industry, this study investigates the potential application of methanol as a fuel in marine boilers. Utilizing the coupled VOF-DPM method in combination with the AMR adaptive mesh refinement technique, numerical simulations were conducted to analyze the atomization process in the nozzle of a methanol-fueled boiler. The study examines the influence of various loading conditions and nozzle geometries on the atomization characteristics of methanol fuel, as well as the Sauter Mean Diameter (SMD) values. Furthermore, the dynamic evolution mechanisms of primary and secondary fragmentation of the methanol jet, driven by gas-liquid interfacial fragmentation, were explored.Results indicate that under high load conditions, the combined effects of inertial force and aerodynamic influence dominate the atomization process. In contrast, under medium load conditions, a liquid ring structure forms due to liquid reflux. Atomization performance is found to be optimal under low load conditions. The nozzle diameter significantly affects the air inlet mass flow rate, with a 20%-50% increase in SMD observed in small diameter nozzles under high and medium load conditions, resulting from a reduction in air mass flow rate. In low load conditions, however, the effect of nozzle diameter on the SMD is less pronounced. This study provides a comprehensive understanding of the methanol atomization mechanism and the multi-factor coupling effects, offering valuable theoretical insights for optimizing nozzle design, enhancing fuel utilization efficiency, and reducing carbon emissions in marine boilers.