Iron Overload-Dependent Ferroptosis Aggravates LPS-Induced Acute Lung Injury by Impairing Mitochondrial Function.

Ferroptosis is a newly proposed form of programmed cell death that is iron-dependent and closely linked to oxidative stress. Its specific morphological changes include shrunken mitochondria, increased density of mitochondrial membrane, and rupture or disappearance of mitochondrial cristae. The main mechanism of ferroptosis involves excessive free iron reacting with membrane phospholipids, known as the Fenton reaction, resulting in lipid peroxidation. However, the role of iron in acute lung injury (ALI) remains largely unknown. In this study, LPS was instilled into the airway to induce ALI in mice. We observed a significant increase in iron concentration during ALI, accompanied by elevated levels of lipid peroxidation markers such as malonaldehyde (MDA) and 4-hydroxynonenal (4-HNE). Treatment with the iron chelator deferoxamine (DFO) or ferroptosis inhibitor ferrostatin-1 (Fer-1) reversed lipid peroxidation and significantly attenuates lung injury. Similarly, DFO or Fer-1 treatment improved the cell survival significantly in vitro. These results demonstrated that ferroptosis occurs during ALI and that targeting ferroptosis is an effective treatment strategy. Interestingly, we found that the increased iron was primarily concentrated in mitochondria and DFO treatment effectively restored normal mitochondria morphology. To further confirm the damaging effect of iron on mitochondria, we performed mitochondrial stress tests in vitro, which revealed that iron stimulation led to mitochondrial dysfunction, characterized by impaired basal respiratory capacity, ATP production capacity, and maximum respiratory capacity. MitoTEMPO, an antioxidant targeting mitochondria, exhibited superior efficacy in improving iron-induced mitochondrial dysfunction compared to the broad-spectrum antioxidant NAC. Treatment with MitoTEMPO more effectively alleviated ALI. In conclusion, ferroptosis contributes to the pathogenesis of ALI and aggravates ALI by impairing mitochondrial function.

Experimental study and techno-economic analysis of co-processing system for treatment of food waste with various impurities.

The study assessed a co-processing system segregating food waste (FW) with different impurities into liquid (slurry) and solid fractions and treated using anaerobic digestion (AD) and pyrolysis (Py), respectively, which is defined as ADCo-Py. Biomethane potential tests showed higher methane yield from the FW slurry fraction (572.88 mL/gVSFW) compared to the whole FW (294.37 mL/gVSFW). Pyrolyzing the FW solid fraction reduced nitrogen compounds in bio-oil by 62 % compared to the whole FW. The energy balance and economic feasibility of ADCo-Py were compared with stand-alone AD, Py, and AD integrated with incineration (ADCo-INC). While all systems required extra energy, stand-alone Py and ADCo-INC needed 3.8 and 2.8 times more energy than ADCo-Py, respectively. Techno-economic analysis favored ADCo-Py, with a net present value (NPV) of $15 million and an internal rate of return (IRR) of 34 %. These findings highlighted FW separation as a promising approach, aligning with energy and economic goals in sustainable FW management.

[Emission Inventory of Airborne Pollutants from Biomass Combustion in Guizhou Province].

With the objective to ascertain the emissions of biomass combustion in Guizhou, the activity levels were measured through data collection and field surveys, and the emission factors were acquired using actual monitoring data and data cited from previous literature. A 3 km×3 km-gridded emission inventory of nine air pollutants from biomass combustion sources in Guizhou Province in 2019 was developed in combination with GIS technology. The results showed that the total emissions of CO, NOx, SO2, NH3, VOCs, PM2.5, PM10, BC, and OC in Guizhou were estimated to be 293505.53, 14781.19, 4146.11, 8501.07, 45025.70, 39463.58, 41879.31, 6832.33, and 15134.74 t, respectively. The distribution of atmospheric pollutants emitted by biomass combustion sources in different cities was noticeably uneven, being mainly concentrated in Qiandongnan Miao and Dong Autonomous Prefecture. The analysis of variation characteristics of emissions indicated that the monthly emissions were concentrated in February, March, April, and December, and the hourly emissions peaked daily from 14:00 to 15:00. Some uncertainty remained in the emission inventory. It is necessary to perform in-depth analyses of the accuracy of obtaining activity-level data, localize the emission factors through more combustion experiments in subsequent research for improving the emission inventory of air pollutants from biomass combustion in Guizhou Province, and provide a basis for the cooperative governance of the atmospheric environment.

Insights into the Microscopic Oil-Water Flow Characteristics and Displacement Mechanisms during Waterflooding in Sandstone Reservoir Rock Based on Micro-CT Technology: A Pore-Scale Numerical Simulation Study.

The low oil recovery rate observed in current oil fields is largely attributed to the presence of remaining oil trapped in the pores of porous media during waterflooding. To improve the recovery rate, it is imperative to gain an understanding of the oil-water flow characteristics and displacement mechanisms during waterflooding, as well as to elucidate the underlying mobilization mechanisms of residual oil at the pore scale. In this paper, we explore these issues in depth by numerically investigating the influence of factors such as water injection velocities, oil-water viscosity ratios, and wettability conditions on pore-scale oil-water flow characteristics and oil recovery rate. To this end, we employ a direct numerical simulation (DNS) method in conjunction with the volume of fluid (VOF) method to study the microscopic displacement mechanisms of waterflooding in a reconstructed two-dimensional digital rock core based on micro-CT technology. In addition, the particle tracing method is adopted to identify the flow path and dominant areas during waterflooding in order to mobilize the residual oil within the pores. The findings indicate that the oil-water flow characteristics in porous media are determined by the interplay between capillary and viscous forces. Furthermore, the oil recovery rate is 10.6% and 24.7% lower under strong water-wet and oil-wet conditions than that (32.36%) under intermediate wettability conditions, and the final oil recovery rate is higher under water-wet conditions than under oil-wet conditions. The seepage path and the dominant areas are directly linked to the capillarity formed during waterflooding. The findings of this study are significant in terms of enhancing the recovery rate of residual oil and provide a novel perspective for understanding the waterflooding process.

Unanswered questions on the airborne transmission of COVID-19.

Policies and measures to control pandemics are often failing. While biological factors controlling transmission are usually well explored, little is known about the environmental drivers of transmission and infection. For instance, respiratory droplets and aerosol particles are crucial vectors for the airborne transmission of the severe acute respiratory syndrome coronavirus 2, the causation agent of the coronavirus 2019 pandemic (COVID-19). Once expectorated, respiratory droplets interact with atmospheric particulates that influence the viability and transmission of the novel coronavirus, yet there is little knowledge on this process or its consequences on virus transmission and infection. Here we review the effects of atmospheric particulate properties, vortex zones, and air pollution on virus survivability and transmission. We found that particle size, chemical constituents, electrostatic charges, and the moisture content of airborne particles can have notable effects on virus transmission, with higher survival generally associated with larger particles, yet some viruses are better preserved on small particles. Some chemical constituents and surface-adsorbed chemical species may damage peptide bonds in viral proteins and impair virus stability. Electrostatic charges and water content of atmospheric particulates may affect the adherence of virion particles and possibly their viability. In addition, vortex zones and human thermal plumes are major environmental factors altering the aerodynamics of buoyant particles in air, which can strongly influence the transport of airborne particles and the transmission of associated viruses. Insights into these factors may provide explanations for the widely observed positive correlations between COVID-19 infection and mortality with air pollution, of which particulate matter is a common constituent that may have a central role in the airborne transmission of the novel coronavirus. Supplementary Information: The online version contains supplementary material available at 10.1007/s10311-022-01557-z.

Eutectic Fatty Acids Phase Change Materials Improved with Expanded Graphite.

Low- and ultra-low-grade thermal energy have significant recycling value for energy saving and carbon footprint reduction. Efficient thermal energy storage technology based on phase change materials (PCMs) will help improve heat recovery. This study aimed to develop a composite eutectic fatty acid of lauric acid (LA) and stearic acid (SA) binary system with expanded graphite (EG). The experimental measured eutectic temperature was 31.2 °C with an LA-to-SA mass ratio of 7:3. Afterwards, 1~15 wt.% EG was composited to the eutectic acid, and the thermophysical properties of the composite PCMs were measured by differential scanning calorimetry (DSC) and transient plane source (TPS) methods. The results demonstrated that the phase transition temperature and latent heat of the composite PCMs were stable when the content of EG was more than 5%, and the thermal conductivity and thermal diffusion coefficient of the composite PCMs (10-15 wt.%) increased by 2.4-2.6 and 3.2-3.7 times compared with the pure eutectic acid, respectively. On this basis, a finned-coil-type reservoir was prepared, and an experimental study of heat storage and heat release performance was carried out. The results showed that the heat storage and heat release effects of the heat reservoir were the best when the EG ratio was 10 wt.%. The heat storage time was reduced by 20.4%, 8.1%, and 6.2% compared with the other three EG ratios, respectively; meanwhile, the heat release time was reduced by 19.3%, 6.7%, and 5.3%, respectively.

Analysis and Experimental Study on Water Vapor Partial Pressure in the Membrane Distillation Process.

In membrane distillation, the vapor pressure difference is the driving force of mass transfer. The vapor pressure is generally assumed by the saturation pressure and calculated by the Antoine equation. However, in the actual operation process, the feed solutions usually flow in a non-equilibrium state, which does not meet the theoretical and measurement conditions of the vapor-liquid equilibrium (VLE) state. This study tested the actual water vapor pressure of the pure water, lithium bromide (LiBr) solution, lithium chloride (LiCl) solution, and calcium chloride (CaCl2) solution under different flow conditions. The results showed that the actual water vapor pressure was lower than the saturation pressure overall, and the difference increased with temperature but decreased with the mass concentration. Therefore, in vacuum membrane distillation (VMD), air gap membrane distillation (AGMD), and sweeping gas membrane distillation (SGMD), the membrane flux calculated by water vapor saturation pressure was higher than the actual membrane flux, and the relative difference decreased and was less than 10% after 60 °C. In direct contact membrane distillation (DCMD), the water vapor pressure difference on both membrane sides was almost the same by using the saturation vapor pressure or the tested data since the pressure errors were partially offset in parallel flow or counter-flow modes.

Fabrication and Characterization of Superhydrophobic Al-Based Surface Used for Finned-Tube Heat Exchangers.

Enhancing the heat transfer performance of heat exchangers is one of the main methods to reduce energy consumption and carbon emissions in heating, ventilation, air-conditioning and refrigeration (HVAC&R) systems. Wettability modified surfaces developed gradually may help. This study aims to improve the performance of heat exchangers from the perspective of component materials. The facile and cost-effective fabrication method of superhydrophobic Al-based finned-tube heat exchangers with acid etching and stearic acid self-assembly was proposed and optimized in this study, so that the modified Al fins could achieve stronger wettability and durability. The effect of process parameters on the wettability of the Al fins was by response surface methodology (RSM) and variance analysis. Then, the modified fins were characterized by field-emission scanning electron microscopy (FE-SEM), 3D topography profiler, X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR), respectively. The durability of the superhydrophobic fins was investigated by air exposure, corrosion resistance, and mechanical robustness experiments. The RSM and variance analysis demonstrated that a water contact angle (WCA) of 166.9° can be obtained with the etching time in 2 mol/L HCl solution of 10.5 min, the self-assembly time in the stearic acid ethanol solution of 48 h, and drying under 73.0 °C. The surface morphology showed suitable micro-nano structures with a mean roughness (Ra) of 467.58 nm and a maximum peak-to-valley vertical distance (Rt) of 4.095 µm. The chemical component demonstrated the self-assembly of an alkyl chain. The WCAs declined slightly in durability experiments, which showed the feasibility of the superhydrophobic heat exchangers under actual conditions.

Research on Health and Thermal Comfort of Unit-Type Student Apartments in the Western China Science and Technology Innovation Harbor.

Background: In China, the collective living mode of "multiple people living in one room" is widely used in college students' dormitories; the space environment has high personnel density and poor thermal comfort and healthy environment. The unit-type apartments were completed in the western China science and technology innovation harbor that considers personal independence and public activity spaces. Aim: The purpose of this study is to explore the applicability, thermal comfort, healthy environment, and the correlation of influencing variables of the new unit-type apartment. Especially the influence of physical parameters on personal space under heating in winter and air conditioning in summer. Method: The field investigations and questionnaires to conduct a personal study of architectural space, healthy environment, and thermal comfort were carried out, and the measurement tests of the building's physical environment were carried out in winter and summer semesters. Results: The questionnaires survey shows that the privacy of the unit apartment is satisfactory, and the independent learning and communication is increased. The field measurement results show that due to the narrow space of the private room, the floor radiant heating mode still forms a hot and dry thermal environment in winter, and the temperature fluctuates significantly after the air conditioner is turned on in summer. Conclusions: The unit-type apartments align with young students' physiological and psychological characteristics and the behavioral aspects of postgraduates, with high comprehensive satisfaction up to 80%. However, the indoor thermal environment quickly fluctuates due to the narrow independent space. Moreover, 90% of the window ventilation ratio shows that it has become the main measure to actively regulate the indoor climate, which is beneficial to students' health but increases energy waste and further aggravates the fluctuation of the thermal environment. More refined regulations should be executed for heating in winter and air conditioning in summer.

Low Eosinophil Phenotype Predicts Noninvasive Mechanical Ventilation Use in Patients with Hospitalized Exacerbations of COPD.

RATIONALE: Eosinophilic inflammation is related to the progression and outcomes of acute exacerbation of chronic obstructive pulmonary disease (AECOPD). Till now, few studies have focused on low EOS in AECOPD. OBJECTIVE: To reveal the clinical characteristics, therapeutic responses and prognosis of patients hospitalized of AECOPD with low EOS. METHODS: The electronic database of Zhongshan Hospital, Fudan University was used. Cohort 1 included 608 patients with hospitalized AECOPD. Study population 2 consisted of 166 patients with AECOPD admission at least twice. Impact of low EOS on NIMV treatment, length of hospital stays and 12-month AECOPD-related readmission were analyzed with multivariable logistic regression model. Thirty-five hospitalized AECOPD patients were prospectively recruited as cohort 3 to explore the association between EOS and other immune cells using Spearman correlation coefficient for ranked data. RESULTS: EOS level was suppressed on admission in AECOPD patients, and significantly improved after hospitalized treatment (P < 0.05). For inflammatory markers, leucocytes, neutrophils and lactate dehydrogenase levels were higher, while lymphocytes, monocytes and interleukin-6 levels were lower in the low-EOS group than those in the non-low EOS group (P < 0.05). Low EOS (EOS < 50 cells/µL) was an independent risk factor of NIMV use (OR = 1.86, 95% CI = 1.26 ~ 2.73). The EOS percentage was positively correlated with the T cell percentage (r = 0.46, P < 0.05) and negatively correlated with the natural killer cell percentage (r = -0.39, P < 0.05). The patients with low EOS had lower level of CD4+ T cell (P < 0.05) than that of patients with non-low EOS. CONCLUSION: Low EOS might be a stable phenotype in patients with hospitalized AECOPD and could be used to inform NIMV management, hyperinflammatory state and impaired immunity situation.

Concomitant preoperative airflow obstruction confers worse prognosis after trans-thoracic surgery for esophageal cancer.

Background: Airflow obstruction is a critical element of chronic airway diseases. This study aimed to evaluate the impact of preoperative airflow obstruction on the prognosis of patients following surgery for esophageal carcinoma. Methods: A total of 821 esophageal cancer patients were included and classified into two groups based on whether or not they had preoperative airflow obstruction. Airflow obstruction was defined as a forced expiration volume in the first second (FEV1)/forced vital capacity (FVC) ratio below the lower limit of normal (LLN). A retrospective analysis of the impact of airflow obstruction on the survival of patients with esophageal carcinoma undergoing esophagectomy was performed. Results: Patients with airflow obstruction (102/821, 12.4%) had lower three-year overall (42/102, 58.8%) and progression-free survival rate (47/102, 53.9%) than those without airflow obstruction (P < 0.001). Multivariate analyses showed that airflow obstruction was an independent risk factor for overall survival (Hazard Ratio = 1.66; 95% CI: 1.17-2.35, P = 0.004) and disease progression (Hazard Ratio = 1.51; 95% CI: 1.1-2.08; P = 0.01). A subgroup analysis revealed that the above results were more significant in male patients, BMI < 23 kg/m2 patients or late-stage cancer (stage III-IVA) (P = 0.001) patients and those undergoing open esophagectomy (P < 0.001). Conclusion: Preoperative airflow obstruction defined by FEV1/FVC ratio below LLN was an independent risk factor for mortality in esophageal cancer patients after trans-thoracic esophagectomy. Comprehensive management of airflow obstruction and more personalized surgical decision-making are necessary to improve survival outcomes in esophageal cancer patients.

EKC Test of the Relationship between Nitrogen Dioxide Pollution and Economic Growth-A Spatial Econometric Analysis Based on Chinese City Data.

During the just concluded 13th Five-Year Plan, China continued to maintain the momentum of rapid economic development, but still faced environmental pollution problems caused by this. Finding the relationship between Nitrogen Dioxide pollution and economic development is helpful and significant in better achieving and optimizing sustainable environmental development. Taking China's 333 prefecture-level cities as samples from 2016 to 2018, the spatial lag model (SAR) was used to study the impact of economic growth on urban Nitrogen Dioxide pollution. The results show that Nitrogen Dioxide has strong positive characteristics of spatial spillover, but there is a linear relationship between economic growth and Nitrogen Dioxide concentration that slowly rises, and there is no inverted U-shaped relationship, which does not support the Environmental Kuznets Curve (EKC) hypothesis; The results also show the impact of per capita GDP, natural gas consumption, residential natural gas consumption, industrialization, and transportation development on the increase of Nitrogen Dioxide concentration, and the impact of green coverage on the decrease of Nitrogen Dioxide concentration. However, there is no significant relationship between technological investment and Nitrogen Dioxide concentration. The above conclusions are still valid after the robustness test, and recommendations are put forward to reduce Nitrogen Dioxide pollution.

Sandstorms and desertification in Mongolia, an example of future climate events: a review.

As global temperatures continue to increase and human activities continue to expand, many countries and regions are witnessing the consequences of global climate change. Mongolia, a nomadic and picturesque landlocked country, has battled with ongoing desertification, recurring droughts, and increasingly frequent sandstorms in recent decades. Here we review the abrupt changes in the climate regime of Mongolia over the recent few decades, by focusing on atmospheric events, land degradation and desertification issues, and the resulted sandstorms. We found that between mid-March to mid-April 2021, the country encountered violent gusts of wind, the Mongolia cyclone, and the largest sandstorms in a decade, causing extensive damages nationwide and trans-regional impact in East Asia including northern China, Japan, and most parts of South Korea. A multitude of factors have contributed to this current ecological crisis. Since 1992, the country has transformed to a market economy with high economic growth driven by mineral and agricultural exports. Overgrazing along with intensified human activities such as coal mining has contributed to the widespread land degradation in Mongolia, while climate change has become a major driving factor for recurring droughts. Annual mean air temperature in Mongolia increased by 2.24 °C between 1940 and 2015, while annual precipitation decreased by 7%, resulting in a higher aridity across the country. A positive feedback loop between soil moisture deficits and surface warming has led to a hotter and drier climate in the region, with over a quarter of lakes greater than 1.0-km2 dried up in the Mongolian Plateau between 1987 and 2010. Increased temperatures, decreased precipitation coupled with land degradation have resulted in a persisting drying trend, with more than three-quarters of land in Mongolia being affected by drought and desertification. The 2021 East Asia sandstorms drew international attention to ecological issues that have culminated for decades in Mongolia. Collaborative efforts from policy makers, local residents, and scientists from both its local and the global research community are urgently needed to address the grand and rapidly aggravating ecological challenges in Mongolia.

Spatial distribution characteristics of PM2.5 and PM10 in Xi'an City predicted by land use regression models.

PM2.5 and PM10 could increase the risk for cardiovascular and respiratory diseases in the general public and severely limit the sustainable development in urban areas. Land use regression models are effective in predicting the spatial distribution of atmospheric pollutants, and have been widely used in many cities in Europe, North America and China. To reveal the spatial distribution characteristics of PM2.5 and PM10 in Xi'an during the heating seasons, the authors established two regression prediction models using PM2.5 and PM10 concentrations from 181 monitoring stations and 87 independent variables. The model results are as follows: for PM2.5, R2 = 0.713 and RMSE = 8.355 µg/m3; for PM10, R2 = 0.681 and RMSE = 14.842 µg/m3. In addition to the traditional independent variables such as area of green space and road length, the models also include the numbers of pollutant discharging enterprises, restaurants, and bus stations. The prediction results reveal the spatial distribution characteristics of PM2.5 and PM10 in the heating seasons of Xi'an. These results also indicate that the spatial distribution of pollutants is closely related to the layout of industrial land and the location of enterprises that generate air pollution emissions. Green space can mitigate pollution, and the contribution of traffic emission is less than that of industrial emission. To our knowledge, this study is the first to apply land use regression models to the Fenwei Plain, a heavily polluted area in China. It provides a scientific foundation for urban planning, land use regulation, air pollution control, and public health policy making. It also establishes a basic model for population exposure assessment, and promotes the sustainability of urban environments.

Examining the physical and chemical contributions to size spectrum evolution during the development of hazes.

China has experienced severe hazes with high concentrations of particulate matter in recent years. The understanding of the size spectrum evolution of submicron particulate matter is critical to making efficient remediation policies to minimize the regional and global environmental impacts from hazes. During a time period of about one month, we monitored five severe haze episodes in Xi'an and four severe haze episodes in Beijing, which were characterized by two distinct kinds of aerosol mass concentration growth processes: accumulative-rise and abrupt-rise. A new method was developed to quantitatively evaluate the physical and chemical contributions to growth processes by analysing the size spectrum evolution data. The results showed that the accumulative-rise processes are governed by primary emissions and the abrupt-rise processes are governed by secondary chemical reactions. The population balance equations (PBE) were used to describe the variation of size spectrum of fine particulate matter, and the respective contributions of the physical aggregation rate and the chemical growth rate. The PBE model is solved using the adjustable direct quadrature method of moments (ADQMOM) to simulate the abrupt-rise process of haze development and to calibrate the contribution of the physical and chemical effects on the size spectrum of aerosol particles.

UASB-modified Bardenpho process for enhancing bio-treatment efficiency of leachate from a municipal solid waste incineration plant.

Generally, the bio-treatment effluent of municipal solid waste incineration (MSWI) leachate was difficult to meet the local leachate discharge standards for chemical oxygen demand (COD) (100 mg/L), ammonia nitrogen (NH4+-N) (25 mg/L), and total nitrogen (TN) (40 mg/L), and advanced treatment (such as coagulation, membrane filtration, advanced oxidation) is required. However, the cost of advanced treatments is proportional to the concentration of the pollutant. Therefore, improved bio-treatment efficiency is the key to reduce the treatment cost of MSWI leachate. In this study, the up-flow anaerobic sludge blanket (UASB) -modified Bardenpho process was used for the treatment of MSWI leachate. The results showed that it was feasible to dilute the leachate by recirculation of the settling tank effluent, which has great significance in the bio-treatment efficiency. The treatment process achieved removal efficiencies of COD and NH4+-N of 97.5-99.5% and 99.3-99.7%, respectively. Adjustments to the operational conditions of the primary anoxic tank, such as adding an organic carbon source and increasing the hydraulic retention time and the nitrification reflux ratio resulted in a TN removal efficiency of 97.7-98.7%. Controlling the generation of dissolved organic nitrogen (DON) and increasing its removal efficiency significantly improved the TN removal efficiency. The concentrations of NH4+-N and TN in the settling tank effluent complied with the local leachate discharge standard, which minimized the cost of advanced treatment. The results provide new ideas for enhancing the bio-treatment efficiency of leachate and theoretical and technical support for reducing the cost of treatment.

Severe haze in northern China: A synergy of anthropogenic emissions and atmospheric processes.

Regional severe haze represents an enormous environmental problem in China, influencing air quality, human health, ecosystem, weather, and climate. These extremes are characterized by exceedingly high concentrations of fine particulate matter (smaller than 2.5 µm, or PM2.5) and occur with extensive temporal (on a daily, weekly, to monthly timescale) and spatial (over a million square kilometers) coverage. Although significant advances have been made in field measurements, model simulations, and laboratory experiments for fine PM over recent years, the causes for severe haze formation have not yet to be systematically/comprehensively evaluated. This review provides a synthetic synopsis of recent advances in understanding the fundamental mechanisms of severe haze formation in northern China, focusing on emission sources, chemical formation and transformation, and meteorological and climatic conditions. In particular, we highlight the synergetic effects from the interactions between anthropogenic emissions and atmospheric processes. Current challenges and future research directions to improve the understanding of severe haze pollution as well as plausible regulatory implications on a scientific basis are also discussed.

Reaction yield model of nitrocellulose alkaline hydrolysis.

Military nitrocellulose waste is flammable and explosive, and thus requires safe disposal and resource utilization. The alkaline hydrolysis process is a potential treatment method for nitrocellulose waste. In this study, a reaction yield model of nitrocellulose alkaline hydrolysis reaction was studied. For this purpose, a theoretical reaction yield model of nitrocellulose alkaline hydrolysis was developed based on Fick's law and scanning electron microscopy analysis. Additionally, the reaction yield model was experimentally validated. The results revealed a linear relationship between the nitrocellulose alkaline hydrolysis rate of xNC and the reaction time of t, which is given by t/tf = xNC. The limiting step of the alkaline hydrolysis of nitrocellulose is the rate of diffusion of OH- through the large pore channels. Accordingly, the reaction rate of the nitrocellulose alkaline hydrolysis can be increased by increasing the KOH concentration, reaction temperature, and reducing the size of the nitrocellulose granules. Thus, this model provides theoretical and technical support for the safe disposal and resource utilization of nitrocellulose waste.

From dust devil to sustainable swirling wind energy.

Dust devils are common but meteorologically unique phenomena on Earth and on Mars. The phenomenon produces a vertical vortex motion in the atmosphere boundary layer and often occurs in hot desert regions, especially in the afternoons from late spring to early summer. Dust devils usually contain abundant wind energy, for example, a maximum swirling wind velocity of up to 25 m/s, with a 15 m/s maximum vertical velocity and 5 m/s maximum near-surface horizontal velocity can be formed. The occurrences of dust devils cannot be used for energy generation because these are generally random and short-lived. Here, a concept of sustained dust-devil-like whirlwind is proposed for the energy generation. A prototype of a circular shed with pre-rotation vanes has been devised to generate the whirlwind flow by heating the air inflow into the circular shed. The pre-rotation vanes can provide the air inflow with angular momentum. The results of numerical simulations and experiment illustrate a promising potential of the circular shed for generating swirling wind energy via the collection of low-temperature solar energy.

The role of water content in triboelectric charging of wind-blown sand.

Triboelectric charging is common in desert sandstorms and dust devils on Earth; however, it remains poorly understood. Here we show a charging mechanism of sands with the adsorbed water on micro-porous surface in wind-blown sand based on the fact that water content is universal but usually a minor component in most particle systems. The triboelectric charging could be resulted due to the different mobility of H(+)/OH(-) between the contacting sands with a temperature difference. Computational fluid dynamics (CFD) and discrete element method (DEM) were used to demonstrate the dynamics of the sand charging. The numerically simulated charge-to-mass ratios of sands and electric field strength established in wind tunnel agreed well with the experimental data. The charging mechanism could provide an explanation for the charging process of all identical granular systems with water content, including Martian dust devils, wind-blown snow, even powder electrification in industrial processes.