Search

The sources and sinks of nitrous oxide, as control emissions to the atmosphere, are generally poorly constrained for most environmental systems. Initial depth-resolved analysis of nitrous oxide flux from observation wells and the proximal surface within a nitrate contaminated aquifer system revealed high subsurface production but little escape from the surface. To better understand the environmental controls of production and emission at this site, we used a combination of isotopic, geochemical, and molecular analyses to show that chemodenitrification and bacterial denitrification are major sources of nitrous oxide in this subsurface, where low DO, low pH, and high nitrate are correlated with significant nitrous oxide production. Depth-resolved metagenomes showed that consumption of nitrous oxide near the surface was correlated with an enrichment of Clade II nitrous oxide reducers, consistent with a growing appreciation of their importance in controlling release of nitrous oxide to the atmosphere. Our work also provides evidence for the reduction of nitrous oxide at a pH of 4, well below the generally accepted limit of pH 5.

Activated Tungsten Inert Gas (A-TIG) welding, a variant of tungsten inert gas (TIG) welding, was used for welding P91. In Generation IV power plants, P91 welds are prone to premature failure due to the presence and formation of brittle phases and creep at high temperatures. When performing A-TIG welding, the flux composition plays a role in the reversal of the Marangoni flow in the weld pool, which ultimately determines the level of penetration achieved. A-TIG gave a complete penetration of 8 mm in the P91 weld. The weldment exhibited non-uniform growth of microstructures with varying grain sizes and precipitates, resulting in variation in mechanical properties. The weld fusion zone (WFZ) had a martensitic structure. The standard flat tensile test specimens were found to fail in the base metal and the fine-grain heat affected zone (FGHAZ) region. The sub-size flat tensile test specimen gave a high strength of 863 ± 10 MPa, failing in the WFZ. The high temperature tensile test specimens had the tensile strength of 512 ± 10 MPa (at 450 °C) and 469 ± 10 MPa (at 450 °C). In both the high temperature tensile test specimens, failure occurred in the base metal region. The impact toughness was recorded at 76 ± 15 Joules due to the presence of untempered martensite in the AW state, and in the PWHT state, the impact toughness increased up to 98 ± 15 Joules. In the AW state, the coarse grain heat affected zone (CGHAZ) region was observed with a maximum microhardness of 450 ± 5 HV and WFZ 460 ± 5 HV. The post-weld heat treatment (PWHT) was successfully performed to temper the martensite and impart some ductility to the weld. The A-TIG weld had sufficient benchmark strength, and the study successfully concluded its aim. [ABSTRACT FROM AUTHOR]

The use of inserts allows for the selective reinforcement of castings to improve mechanical properties, including surface hardness and wear rate. Metal surfaces that undergo wear on account of friction can be strengthened using metal matrix composite (MMC) inserts. An essential factor in the manufacture and application of compound casting involving MMC inserts has been the bond strength between the insert and alloy. This work studied fluxes (CsAlF4 and LiAlF4), preheating, and nickel (Ni) plating to improve the bond strength between A206 and A201-Al2SiO5 fiber MMC. It was observed that Flux 1 (G-2004), Flux 2 (CS-2020), and Ni plating, when used with preheating the insert up to 200 °C, led to the formation of a diffusion bond. The effect of fluxes and plating has been discussed, along with the impact of the insert oxide layer on the formation of diffusion bonds. The microstructure formed at the interface between casting and insert was analyzed. [ABSTRACT FROM AUTHOR]

The results of the thermalized flux calculation that incorporate radiative capture reactions in the presence and absence of polyethylene blocks that form an enclosure for a deuteron-deuteron (D-D) neutron generator are presented. This method can be used to measure the moderated neutron flux component in a mixture of moderated and primary neutron spectra. Using 20-cm-thick polyethylene blocks to surround a D-D neutron generator, the moderation of primary neutrons was investigated using nine indium foils. In this paper, the relationship between the moderated neutron flux and the radiative capture rates in the presence and absence of polyethylene blocks is derived. This is compared to a MCNP simulation and a calculation of modulated flux that ignore the primary neutron components. [ABSTRACT FROM AUTHOR]

Numerous efforts to measure land surface fluxes, from leaf to canopy scales, have significantly advanced the field of biogeoscience. However, upscaling these estimates to larger spatial and temporal scales remains a challenge. Recent advancements in remote sensing provide new opportunities to bridge these gaps in upscaling efforts. In this review, I propose that emerging satellite data can support the robust upscaling of land surface fluxes in terms of space through constellations of low Earth orbit satellites, in time through geostationary satellites, and in spectrum via optical, thermal, and microwave satellites. Lastly, I recommend the development of a long‐term network integrating tower‐based hyperspectral, thermal, and microwave instruments to rigorously evaluate the upscaling process of land surface fluxes. Plain Language Summary: Scientists are studying how carbon and energy are exchanged between the biosphere and the atmosphere, a process vital to our climate. Understanding this exchange requires interpreting data from small, specific areas and extending these findings to larger regions and longer time periods. Advances in space technology are helping us make progress in this area. This article recommends integrating diverse satellite types to gain a wider perspective. Some satellites orbit close to Earth, offering detailed frequent updates, while others are positioned much farther away, providing constant monitoring of specific areas. These satellites use various parts of the light spectrum to discern different aspects of the Earth's surface. Additionally, the study suggests a long‐term vision integrating these satellite observations with ground‐level measurements to enhance the accuracy of our understanding of terrestrial carbon and energy cycles. Key Points: Measuring land surface fluxes has advanced biogeoscience but upscaling remains a challengeNew satellites support upscaling fluxes spatially, temporally, and spectrallyLong‐term flux networks with spectral sensors are vital for accurate flux upscaling [ABSTRACT FROM AUTHOR]

Magnetic flux leakage from the rotor core bridge must be improved in interior permanent magnet motors to improve their performance. The partial non-magnetization of bridges is effective in reducing magnetic flux leakage. In our previous studies, we proposed a new partial nonmagnetization process for silicon steel, which was used for the rotor core. The portion of the silicon steel sheets that becomes a bridge after pressing can be non-magnetized by melting and mixing Ni-Cr-B alloy powder with the silicon steel sheets using a laser beam and then laminated to produce the rotor core. In this study, the effect of B addition to Ni-Cr alloy powder was widely investigated to optimize the B addition amount. Based on the appearance, solidification defect, and magnetic and mechanical strength properties of the improved portion, the optimal content of B was within the range of 0.5-1.0 mass%. Furthermore, core sheet samples with an improved portion, which had the improved length of 1.0mm and has the composition of Fe-13.9 mass%Cr-15.1 mass%Ni-2.3 mass%Si-0.5 mass%B, were prepared by laser and press processing. A rotor core was fabricated using core sheets and evaluated for its magnetic flux and high-speed rotation for practical use. The prototype rotor core exhibited a 32% higher magnetic force and could rotate at speeds of up to 43,000 rotations. It is expected that the size of interior permanent magnet motors will be reduced due to the increased magnetic force. [ABSTRACT FROM AUTHOR]

Direct Contact Membrane Distillation (DCMD) uses low heat sources to separate water from urea, which was then used as a plasticizer in regolith-based cement to make it more workable. The work investigated separating potable water and urea from artificial urine using DCMD and then characterizing the products. Water was successfully separated from the artificial urine solution as characterized by density, conductivity, pH, and substance concentrations. The concentrated urine solution was used in regolith-based cement cured under vacuum at temperatures that simulated temperatures that would be expected in construction on the Moon. Workability and other properties were improved by replacing water with concentrated urine solution in the mix. [ABSTRACT FROM AUTHOR]

Seasonal variations in the atmospheric boundary layer over different geographical regions have distinct features due to variations in topography, land cover, and geographical position. This study focuses on Atmospheric boundary layer height (ABLH) characteristics seasonally and diurnally over the Indo-Gangetic Plain (Varanasi) and Coastal region (Goa). The study also emphasizes the relationship between ABLH and associated variables such as surface sensible heat flux (SSHF), surface latent heat flux (SLHF), convective available potential energy (CAPE), and Relative humidity (RH) for pre-monsoon and monsoon season. ECMWF-ERA-5 reanalysis data for the period of 2015 to 2017 were used for the study. ECMWF-ERA-5 reanalysis data was validated with MERRA-2 data using correlation coefficient (r) and Factor of Two (FAC2) value. Validation suggested the reliability of ECMWF-ERA-5 data which showed an r-value of 0.8 and FAC2 value in ≥ 0.5 ≤ 2.0 range with MERRA-2 data. The results showed 1400–1800 m and 1000–1400 m ABLH during pre-monsoon and monsoon respectively over Varanasi while ABLH of 1000–1400 m and 500–700 m was seen over Goa during pre-monsoon and monsoon respectively. The analysis indicated that deeper ABLH was observed over Varanasi than over Goa during both seasons. Further, regression correlation analysis detailed the parameters affecting the ABL height characteristics. Surface heat fluxes showed a stronger correlation with ABLH over Varanasi than over Goa. Regression coefficients for ABLH and surface sensible heat flux (SSHF) were found to be 0.88 and 0.82 during pre-monsoon and monsoon respectively over Varanasi and 0.76 and 0.66 during pre-monsoon and monsoon respectively over Goa. Surface latent heat flux (SLHF) also showed significant regression coefficients of 0.83 and 0.62 over Varanasi and 0.76 and 0.66 over Goa during premonsoon and monsoon respectively. Multivariate regression analysis quantified the effect of independent variables (SSHF, SLHF, CAPE, RH) on the dependent variable (ABLH) by estimating β coefficient. The variables which affected ABLH at a significant level (α = 0.05) were heat fluxes (SSHF and SLHF) and CAPE during pre-monsoon over both regions. Significant contributor to ABL height found to be SLHF over Goa during monsoon. South westerly moist winds and buoyant thermals might have impacted the ABLH over Goa because latent heat flux is highly affected by surface winds and specific humidity gradient at surface and atmosphere. Also, uninterrupted moisture supply along with strong onshore winds strengthen the SLHF. Furthermore, the geographical location of Goa might have amplified the variable effects shaping ABLH during the monsoon. On the other hand, significant contributors were SSHF, SLHF and CAPE over Varanasi during the same season i.e. monsoon. [ABSTRACT FROM AUTHOR]

The matric suction in unsaturated soil depends on the type of soil and various flux conditions i.e., infiltration, evaporation and no flow. The shear strength of unsaturated soil changes with change in matric suction leading to varying resistance of soil under various flow conditions. In this study, the bearing capacity of strip foundations resting over unsaturated clay considering variation of matric suction with depth for different surface flux conditions and position of water table, has been obtained using finite element lower bound limit analysis. Modified Mohr-Coulomb yield criteria based on unified effective stress approach has been employed to incorporate the contribution of matric suction stress to the failure condition. A non-dimensional bearing capacity factor was introduced to estimate the bearing capacity of strip foundations and presented as a function of different influencing parameters such as foundation width, water table depth, soil properties, various flow conditions and their flow rate, and surcharge pressure. The influence of variation of unit weight of soil in the unsaturated zone, air entry and pore size distribution parameters, residual degree of saturation of soil, specific gravity of soil solids, and foundation-soil interface roughness on the bearing capacity has also been examined and found to be insignificant. [ABSTRACT FROM AUTHOR]

Parallel artificial membrane permeability analysis (PAMPA) is used to determine the permeability of compounds through concentrated negatively charged phospholipid bilayer barriers. We employed MacroFlux (a scaled-up version of PAMPA) to test the permeation rate of terazosin hydrochloride (TH) tablets and predict in vivo bioequivalence. The dissolution profiles and permeability of one reference formulation, and seven generic TH tablets, were compared. The dissolution profiles of these generic tablets were equivalent to that of the reference drug in four different media. However, the flux and the total permeated amount of some generic TH tablets were below the lower limit of the confidence interval of the original acceptance range in MacroFlux, which implied risk in the bioequivalence test in vivo. We further evaluated potential factors responsible for this discrepancy by µFlux, including active pharmaceutical ingredient (API) permeability and excipient prescriptions. The analysis showed that different properties of API were a main factor leading to biological inequivalence in the MacroFlux assay, while excipient prescriptions did not have an impact on bioequivalence risk. These data indicated that the flux assay may be a helpful as an auxiliary method for predicting bioequivalence of generic drugs and analyze the factors responsible for bioequivalence risk. [ABSTRACT FROM AUTHOR]

Acidic water from the coal of mining pool has been polluted from the surrounding coal stockpile stocpile industry. Water quality in mining ponds can threaten the biota in it. During this time, coal mining pool the local community uses water extensively for everyday requirements like drinking, washing, and bathing. More than time it turns out that coal mine acidic water has been polluted. This problem needs to be sought a solution, one of which is required treatment technology for creating water quality that satisfies requirements for drinking water quality. This research tries to use NF270 membrane type Nanofiltration membrane technology to eliminate COD, TSS, TDS, and metal parameters (Fe, Mn). This research was conducted by analyzing the influence pressure (4, 5, and 6 bar) on each component's rejection rate and flux each parameter. The results of the study show the processed results as follows; Turbidity, Color, COD, TSS, TDS, Fe and Mn at pressures 4, 5, and 6 bar of acid mine rejection water values, namely; Turbidity (96.23%; 98.7%; 100%), Color (79%; 98%; 100%), COD (57.9%; 63.7%; 83.19%), TSS (73, 3%; 87.2%; 95.8%), TDS (62.7%; 66%; 70.19%), Fe (36%; 74.5%; 100%), Mn (100%; 100 %; 100%). Acidic water treatment in coal mining ponds can be turned into drinking water using nanofiltration membranes producing the best percentage of rejection at pressures of 5 and 6 bar. Water treatment with Nanofiltration membrane technology has produced treated water in accordance with drinking water quality standards required by Priest of Wellbeing Pronouncement of the Republic of Indonesia No. 907/Menkes/Sk/VII/2002 and Clergyman of Climate Pronouncement the Decree of the Minister of Environment No. 492 / IV / 2010 / MENKES / PER. NF 270 membrane can remove heavy metals and other impurities in acidic water by more than 90%. [ABSTRACT FROM AUTHOR]

Foamed ceramics with high closed porosity were prepared using granite scrap as the raw material and silicon carbide as a foaming agent, and the effects of Na2O, K2O, and MgO on the pore structure and properties of the foamed ceramics were investigated. The results show that both Na2O and K2O could reduce the viscosity of the melt and promote the formation of the liquid phase, and the increase in content could enhance the foaming ability of the blank. When the dosage of Na2O was 4–6 wt% and the dosage of K2O was 6–8 wt%, the homogeneity of the pore structure of the foamed ceramics could be effectively improved, and the samples exhibited an optimal performance, including a bulk density of 510.36–593.33 kg/m3, a closed porosity of 68.24–78.04%, a compressive strength of 1.33–2.66 MPa, and a water absorption capacity of 0.57–1.31%. A further increase in the Na2O and K2O dosages destroyed the uniformity of the pore structure, resulting in a large number of irregular macropores. MgO had a slight effect on regulating the pore structure of the foamed ceramics, and the increase in dosage promoted the precipitation of forsterite crystals, creating conditions suitable for the preparation of foamed ceramics with small pores. [ABSTRACT FROM AUTHOR]

The effectiveness of using borate (borax) and fluoride (sodium fluoride) fluxes in the sintering of crystalline (sand) and amorphous (diatomite) silicate raw materials was considered. The change in the density and appearance of samples with varying amounts of fluxes during their heat treatment at different temperatures was described. It was shown that the introduction of 4 wt.% of borax reduces the temperature necessary to reach a density of 1500 kg/m3 by 100°C, and 6 wt.% of borax by 200°C. It was shown that the introduction of fluxes increases the amount of x-ray amorphous glass phase due to depolymerization of the silicon-oxygen network and the formation of a low-temperature melt. [ABSTRACT FROM AUTHOR]

Supplement illumination is indispensable in the indoor plant cultivation domain. In this research work, double perovskite Ca 2 LuNbO 6 :Mn4+ phosphors were produced. A strategy of enhancing luminescence performance by utilizing A-site cationic fluoride as a flux was proposed. The structure and morphology of Ca 2 LuNbO 6 :Mn4+ phosphor was characterized. Under the excitation of 360 nm, the emission spectra of Ca 2 LuNbO 6 :Mn4+ phosphor cover from 600 nm to 750 nm peaking at 683 nm. It benefits the red section of chlorophyll absorption band and possesses the wavelengths of 680 nm and 700 nm demanded by photosystem I (PS I) and photosystem II (PS II) to realize Emerson enhancement effect. After adding CaF 2 as flux, the emission intensity increases by 2.5 times. Due to its compatibility with the A-site cation of host, CaF 2 agent not only lower the sintering temperature but also increase the crystallite size, which result in the enhancement of luminescence. The D q /B and optical band gap of Ca 2 LuNbO 6 host is 2.32 and 3.79 eV, respectively, which show that Mn4+ ions locate in the [NbO 6 ] octahedra of strong crystal field and host has the suitable optical band gap for Mn4+ ions. With the help of CaF 2 , the thermal stability, activation energy Δ E a , internal quantum efficiency of Ca 2 LuNbO 6 :Mn4+ phosphors are promoted at 373 K from 64.8% to 70.7% of that at 273 K, from 0.33 to 0.36 eV, and from 9.1% to 23.5%. The luminescence lifetime of Ca 2 LuNbO 6 :Mn4+ is the order of a fraction of a millisecond. Finally, the as-prepared Ca 2 LuNb 0.996 O 6 :0.004Mn4+ phosphor was successfully fabricated through a 365 nm near ultraviolet (NUV) chip, which has the peak wavelengths of 683 nm and possesses 680 nm and 700 nm demanded by PS I and PS II. It is implied that Ca 2 LuNbO 6 :Mn4+ phosphor-converted light emitting diode has prospective market in the domain of supplement illumination of plant cultivation. [ABSTRACT FROM AUTHOR]

The submerged arc welding (SAW) process is operated at high temperatures, up to 2500 °C, in the arc cavity formed by molten oxy-fluoride flux (slag). These high arc cavity temperatures and the complex interaction of gas–slag–metal reactions in a small space below the arc render the study of specific chemical interactions difficult. The importance of gas phase reactions in the arc cavity of the SAW process is well established. A low-temperature (1350 °C) experimental method was applied to simulate and study the vaporisation and re-condensation behaviour of the gas species emanating from oxy-fluoride flux. Energy dispersive X-ray spectroscopy (EDX) analyses and reaction thermochemistry calculations were combined to explain the role of Al as a de-oxidiser element in gas phase chemistry and, consequently, in nano-strand formation reactions. EDX element maps showed that the nano-strands contain elemental Ti only, and the nano-strand end-caps contain Co-Mn-Fe fluoride. This indicates a sequence of condensation reactions, as Ti in the gas phase is re-condensed first to form the nano-strands and the end-caps formed from subsequent re-condensation of Co-Mn-Fe fluorides. The nano-strand diameters are approximately 120 nm to 360 nm. The end-cap diameter typically matches the nano-strand diameter. Thermochemical calculations in terms of simple reactions confirm the likely formation of the nanofeatures from the gas phase species due to the Al displacement of metals from their metal fluoride gas species according to the reaction: yAl + xMFy ↔ xM + yAlFx. The gas–slag–metal equilibrium model shows that TiO2 in the flux is transformed into TiF3 gas. Formation of Ti nano-strands is possible via displacement of Ti from TiF3 by Al to form Al-fluoride gas. [ABSTRACT FROM AUTHOR]

CaF2 has been a very common constituent in the fluxes used for welding of low‐carbon steel plates, owing to its strong ability to lower the liquidus temperature as well as viscosity of the molten flux. But the adverse impact of fluoride evaporation from molten slag on the health of operating personnel and the environment has prompted a worldwide effort to replace CaF2 with more benign constituents. Three compositions with varying MnO concentration in the CaO–MnO–SiO2–Al2O3 system, identified in the current work, have shown promise in terms of ability to control oxygen transfer and modify inclusion generation in the molten metal during the welding of low carbon low alloy steels. However, the melting behavior of a flux needs to be established before recommending its use for welding. Three compositions, with varying MnO concentration, are chosen in the current work. Aided by experimental measurements using high‐temperature microscopy, DTA and simulations using the commercially available thermodynamic package FactSage (version 8.3), this work aims to understand the melting characteristics of the developed fluxes. These characteristics seem to be comparable with a commercial CaF2‐containing welding flux, used as a reference for comparison. In addition, simulations using FactSage suggest that transfer of dissolved O, Si and Mn to the weld metal, while using these fluxes, would be benefitial to performance of the welded joint. [ABSTRACT FROM AUTHOR]

Background: Mangrove ecosystems exhibit significant carbon storage and sequestration. Its capacity to store and sequester significant amounts of carbon makes this ecosystem very important for climate change mitigation. Indonesia, owing to the largest mangrove cover in the world, has approximately 3.14 PgC stored in the mangroves, or about 33% of all carbon stored in coastal ecosystems globally. Unfortunately, our comprehensive understanding of carbon flux is hampered by the incomplete repertoire of field measurement data, especially from mangrove ecosystem-rich regions such as Indonesia and Asia Pacific. This study fills the gap in greenhouse gases (GHGs) flux studies in mangrove ecosystems in Indonesia by quantifying the soil CO2 and CH4 fluxes for different land use types in mangrove ecosystems, i.e., secondary mangrove (SM), restored mangrove (RM), pond embankment (PE) and active aquaculture pond (AP). Environmental parameters such as soil pore salinity, soil pore water pH, soil temperature, air temperature, air humidity and rainfall are also measured. Results: GHG fluxes characteristics varied between land use types and ecological conditions. Secondary mangrove and exposed pond embankment are potential GHG flux sources (68.9 ± 7.0 and 58.5 ± 6.2 MgCO2e ha− 1 yr− 1, respectively). Aquaculture pond exhibits the lowest GHG fluxes among other land use types due to constant inundation that serve as a barrier for the release of GHG fluxes to the atmosphere. We found weak relationships between soil CO2 and CH4 fluxes and environmental parameters. Conclusions: The data and information on GHG fluxes from different land use types in the mangrove ecosystem will be of importance to accurately assess the potential of the mangrove ecosystem to sequester and emit GHGs. This will support the GHG emission reduction target and strategy that had been set up by the Indonesian Government in its Nationally Determined Contributions (NDC) and Indonesia's 2030 Forest and Other Land Use (FOLU) Net Sink. [ABSTRACT FROM AUTHOR]

The presence of impurities, microorganisms, enzymes, suspended solids, and impurities in unclarified pomelo juice negatively affected the quality and shelf-life of the product in the food industry. The objective of this study focuses on the clarification of fresh pomelo juice using an ultrafiltration (UF) process. The study examined the influence of the operating pressure (OP) on the various quality attributes of pomelo juice, such as pH, total soluble solids (TSS), turbidity, color, total phenolic content (TPC), ascorbic acid content (AAC) and fouling mechanisms and permeate flux (J) behavior. To perform the clarification of pomelo juice, a 100 kDa membrane (polymeric) was used in a dead-end system, and the process was carried out in batch mode at OP values of 1.0, 1.5, 2.0, 2.5 and 3.0 bar. The findings revealed that increasing OP led to higher flux during ultrafiltration with limiting pressure (Plim). The limiting pressure (Plim) was anticipated to be beyond 3.0 bar due to the enzymatic pretreatment. The primary fouling mechanism during the clarification process was total pore blocking. After filtration, the resulting juice showed a significant reduction in turbidity of over 97%, while TSS was lowered by 7–17% compared to fresh juice. The pomelo juice was efficiently clarified while the pH remained stable at ∼3.8. The clarified juice showed a minor decline of 10.1–13.9% in TPC and a 10.8–16.7% reduction in AAC compared to the fresh unclarified juice. In conclusion, a pressure of 3.0 bar is recommended for conducting the ultrafiltration process in order to attain desirable flux behavior and optimum properties of the juice. [ABSTRACT FROM AUTHOR]

Asaoka & Irie [3] recently proved a $ C^{\infty} $ closing lemma of Hamiltonian diffeomorphisms of closed surfaces. We reformulated their techniques into a more general perturbation lemma for area-preserving diffeomorphism and proved a $ C^{\infty} $ closing lemma for area-preserving diffeomorphisms on a torus $ \mathbb{T}^2 $ that is isotopic to identity. i.e., we show that the set of periodic orbits is dense for a generic diffeomorphism isotopic to identity area-preserving diffeomorphism on $ \mathbb{T}^2 $. The main tool is the flux vector of area-preserving diffeomorphisms, which may not be zero as in the Hamiltonian cases. [ABSTRACT FROM AUTHOR]

Industrial and mining operations are classified as the primary sources of particulate matter (PM10) that pose substantial health and environmental risks, with much attention when situated in or near residential areas. The absence of a standardized approach for quantifying air pollutant fluxes in mining areas has been identified as a research gap, particularly given the increasing rate of mining extraction, especially in developing countries. This study used the AERMOD air pollutants dispersion model to analyze PM10 dispersion from the CIMERWA Cement Plant and adjacent mining sites in Rusizi District, Rwanda, throughout 2022. We developed methods to quantify PM10 horizontal and vertical fluxes and their emission rates within the framework of dispersion analysis. Results indicate high concentrations of PM10 in the vicinity of mining areas, with daily, hourly, monthly, and annual maximum mean ground-level concentrations of 158.86 µg m−3, 92.87 µg m−3, 46.15 µg m−3, and 27.65 µg m−3, respectively. Wind erosion, with a daily horizontal speed of 0.66 m s−1 and shear speed of 0.03 m s−1, contributes to a daily mean horizontal flux of 8.50 µg m−2 s−1 and vertical flux of 0.4 µg m−2 s−1 of PM10. Dispersion maps analysis highlights residents' exposure to significant levels of PM10 depicted with 28 discrete receptors in all directions. The circulation of polluted windy air masses substantially impacts regional air quality. The findings offer evidence-based recommendations for strategic mitigation measures targeted at residents, policymakers, stakeholders, and urban planners to address air quality issues arising from industrial mining activities. [ABSTRACT FROM AUTHOR]

Vinasse, a by-product of ethanol production, is generated at significant rates. While rich in nutrients such as calcium, magnesium, and potassium, its high solids, organic matter, acidity, and sulfate content pose challenges when disposed directly on soil, necessitating treatment. Anaerobic digestion is a viable solution, reducing organic pollution while recovering energy in the form of biogas, aligning with the biorefinery concept. Traditionally, sludge bed reactors and anaerobic contact reactors are utilized for vinasse processing, with sludge granulation being vital for treatment success. However, challenges such as sludge wash-out due to recalcitrant compounds, high solids concentration in the influent, low pH, salinity, and temperature hinder granule formation. Anaerobic membrane bioreactors (AnMBR) offer an alternative, simplifying treatment by integrating intensified pre- and post-treatment units. Due to complete sludge retention, AnMBRs achieve high COD removal efficiencies, yielding a suspended solids-free and largely disinfected effluent. Therefore, AnMBRs show promise for vinasse treatment, eliminating the need for sludge granulation and producing nutrient-rich effluent with minimal residual organics and suspended solids. In this study, an AnMBR equipped with an inside-out external crossflow ultrafiltration membrane was proposed for the treatment of vinasse. The AnMBR reached a COD removal efficiency of 95% ± 2.6% and produced 0.3 CH4 L. g COD removed-1 working at organic loading rates of 8 g COD. L-1 d-1 and membrane fluxes of 10 LMH. At organic loading rates of 10 g COD. L-1 d-1 and fluxes of 12 and 14 LMH, the COD removal efficiency decreased to 77% ± 11% and 73% ± 7.9%, respectively. The AnMBR technology represents an innovation for wastewater treatment, however, more research using the cross-flow configuration and different types of effluents is needed. Literature studies that address the treatment of sugar beet or sugarcane vinasse using AnMBR are still scarce. This study explored the potentials of AnMBR technology for vinasse treatment and contributes to the dissemination of this technology, opening new possibilities for vinasse processing.

Relevance. The need to assess the state of the environment based on the use of terminology for quantitative chemical characteristics of the underlying surface as a result of deposition of pollutants in the composition of wet and dry fallout from the atmosphere. Aim. This study can be a source of information about the terminology used to describe the state of the underlying surface during the deposition of substances from the atmosphere, with links to scientific and technical literature. Methods. Review of some scientific and technical literature and an attempt to select terms used to quantify the ecological state of the underlying surface, mainly snow, after the arrival of substances as part of dry and wet deposition from the atmosphere, depending on the sampling method. Results and conclusions. The author has carried out an analysis of the scientific and technical literature and defined the terms applied to a quantity that has the dimension mass/area*time for assessing the ecological state of the snow cover, such as specific reserve (surface density), deposition density, atmospheric deposition density, precipitation intensity pollutant, daily deposition of chemical elements, technogenic load, dust load, pollution load (element), mass load, gas-aerosol load, technogenic pressure module, input module, atmospheric fallout module, mass of the determined component received at unit area, flux obtained on the basis of sampling during snow chemical survey. An analysis of the scientific and technical literature was also carried out and the terms applied to a value with the same dimension mass/area*time were defined to assess the ecological state of the underlying surface during the deposition of substances from the atmosphere, such as "fallout density", "atmospheric fallout density", “pollutant fallout intensity”, “aggravating substance", "precipitation", "critical load", "flow" obtained based on sample collection using plates, cuvettes, collections.

The submerged arc welding (SAW) process is complex because multi-phase reactions occur simultaneously across a large temperature interval from 2500 °C in the arc cavity, down to the weld pool liquidus temperare at the slag-weld pool interface. This complexity hinders research on specific process metallurgy aspects, such as gas formation from the oxy-fluoride slag. The main objective of this work is to illustrate a low temperature experimental technique as an accurate reaction simulation experiment of SAW flux oxy-fluoride slag behaviour in terms of gas formation and metal powder assimilation reaction mechanisms as observed in the SAW process. The oxy-fluoride slag behaviour was confirmed by identification and analyses of nano-strand formation in the reacted slag formed from the reaction of welding flux with Al-Fe-Cr metal powders at 1350 °C. The observed nano-strand formation agrees with similar observations in SAW post-weld slags used to confirm of oxy-fluoride vaporisation and re-condensation. Element distribution from energy dispersive X-ray spectroscopy (EDS) maps and thermochemical calculations were used to gain insights into the reactions in nano-strand formation. The nano-strands contained chromium patches and spots of less than 1 μm in scale, confirming that added Cr metal powder assimilated via the gas phase. Cr-fluoride formed part of the oxy-fluoride slag and likely formed Cr-fluoride gas. Cr was recovered via re-condensation of Cr vapour formed from the reaction of Cr-fluoride with Al gas. This work presents an accurate low temperature simulation method of gas formation and metal powder assimilation reactions in oxy-fluoride slags as in the SAW process.

Abstract The present study aims to evaluate the performance of porous hydrophobic Polyvinylidene fluoride − Polytetrafluoroethylene (PVDF-PTFE) composite membranes for desalination by vacuum membrane distillation (VMD) technique. The effect of operating parameters such as feed NaCl concentration (10,000 to 40,000 mg/L), feed temperature (50 °C to 80 °C), and downstream pressure (80 to 120 mmHg) on water permeation rate was studied. The increase in feed temperature enhanced the water permeation rate due to a rise in driving force across the membrane. For a constant downstream pressure of 80 mmHg, feed temperature of 80 °C and feed flow rate of 80 L/h, the membrane exhibited a maximum water flux of 3 kg/m2h with 99.86% salt rejection when aqueous NaCl concentration of 10,000 mg/L was charged as feed. Membrane characterization was performed using various analytical tools to determine physico-chemical properties such as pore size, structural elucidation, thermal stability, crystallinity, and hydrophobicity of the membrane material. Further, a temperature and concentration polarization coefficient-based analysis was performed by solving the mass and heat transport model equations using MATLAB software. The proposed research study promotes the application of VMD for recovering potable water from highly saline sea/brackish water and alleviates brine disposal issues.

In the aerospace industry, the additive manufacturing of aluminum alloys has encountered significant challenges owing to fusion defects. In this work, the B2O3–NaF–SiO2 fluxes are employed for the first time to improve the fusion defects and mechanical properties of butt-welded A7N01 alloy with unequal thickness under natural ageing. The finite element analysis (FEA) approach is used to account for the evolution mechanism of residual stresses. The simulated results indicate that the distribution and values of residual compressive stresses are improved, which contribute to the microhardness. After applying a coating-position optimization of the B2O3–NaF–SiO2 fluxes, the fluxes plays a role in enhancing the welding current density and increasing the concentration of oxygen elements. The melt pool morphology and the fusion defect of the thicker side are ameliorated, resulting in a considerable increase in the yield strength and the tensile strength. Therefore, this paper establishes the viability of applying B2O3–NaF–SiO2 fluxes for additive manufacturing of A7N01 aluminum alloys and provides new ideas for exploring the optimal active fluxes of other 7xxx series aluminum alloys.

Eddy-covariance (EC) flux measurements in Indianapolis were used to quantify the impact of the COVID-19 lockdown on CO and CO2 emissions from a highway and a suburban neighborhood. CO2 fluxes were measured for 6 weeks pre-lockdown (January 22, 2020–March 3, 2020) and during lockdown (March 25, 2020– May 5, 2020) using EC instrumentation at 41 m AGL. Fossil fuel CO2 emissions (CO2ff) were estimated by calculating eddy diffusivity to obtain CO flux and then scaling by the CO:CO2ff emissions ratio (RCO). Flux measurements segregated by wind direction were compared to hourly emissions from the 2020 Hestia inventory model. The lockdown CO2ff average weekday emissions from the highway estimated by EC decreased by 51.5 ± 10.9% (11.2 ± 2.2 µmol m−2 s−1) compared to pre-lockdown, similar to Hestia’s estimate 56 ± 7% (12 ± 1 µmol m−2 s−1). The EC measurements detected a significant (2.2 ± 0.7 µmol m−2 s−1) but smaller magnitude decrease in CO2ff emissions from the suburban neighborhood. The daily cycles of CO2ff emissions were significantly correlated with Hestia estimates from the highway but not from the suburbs. This study demonstrates that EC flux towers and high-resolution inventory models in regions with mixed and spatially heterogeneous sources can quantify abrupt changes in sector- and source-specific CO2 fluxes.

The wettability of polymers is usually inadequate to ensure the appropriate spreading of polar liquids and thus enable the required adhesion of coatings. A standard ecologically benign method for increasing the polymer wettability is a brief treatment with a non-equilibrium plasma rich in reactive oxygen species and predominantly neutral oxygen atoms in the ground electronic state. The evolution of the surface wettability of selected aromatic polymers was investigated by water droplet contact angles deposited immediately after exposing polymer samples to fluxes of oxygen atoms between 3 × 1020 and 1 × 1023 m−2s−1. The treatment time varied between 0.01 and 1000 s. The wettability evolution versus the O-atom fluence for all aromatic polymers followed similar behavior regardless of the flux of O atoms or the type of polymer. In the range of fluences between approximately 5 × 1020 and 5 × 1023 m−2, the water contact angle decreased exponentially with increasing fluence and dropped to 1/e of the initial value after receiving the fluence close to 5 × 1022 m−2. [ABSTRACT FROM AUTHOR]

In order to develop a standardized nomenclature for the mechanisms and materials utilized during extracorporeal blood purification, a consensus expert conference was convened in November 2022. Standardized nomenclature serves as a common language for reporting research findings, new device development, and education. It is also critically important to support patient safety, allow comparisons between techniques, materials, and devices, and be essential for defining and naming innovative technologies and classifying devices for regulatory approval. The multidisciplinary conference developed detailed descriptions of the performance characteristics of devices (membranes, filters, and sorbents), solute and fluid transport mechanisms, flow parameters, and methods of treatment evaluation. In addition, nomenclature for adsorptive blood purification techniques was proposed. This report summarizes these activities and highlights the need for standardization of nomenclature in the future to harmonize research, education, and innovation in extracorporeal blood purification therapies. [ABSTRACT FROM AUTHOR]

Copyright of Acta Scientiarum Naturalium Universitatis Pekinensis is the property of Editorial Office of Acta Scientiarum Naturalium Universitatis Pekinensis and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The present study aims to evaluate the performance of porous hydrophobic Polyvinylidene fluoride − Polytetrafluoroethylene (PVDF-PTFE) composite membranes for desalination by vacuum membrane distillation (VMD) technique. The effect of operating parameters such as feed NaCl concentration (10,000 to 40,000 mg/L), feed temperature (50 °C to 80 °C), and downstream pressure (80 to 120 mmHg) on water permeation rate was studied. The increase in feed temperature enhanced the water permeation rate due to a rise in driving force across the membrane. For a constant downstream pressure of 80 mmHg, feed temperature of 80 °C and feed flow rate of 80 L/h, the membrane exhibited a maximum water flux of 3 kg/m2h with 99.86% salt rejection when aqueous NaCl concentration of 10,000 mg/L was charged as feed. Membrane characterization was performed using various analytical tools to determine physico-chemical properties such as pore size, structural elucidation, thermal stability, crystallinity, and hydrophobicity of the membrane material. Further, a temperature and concentration polarization coefficient-based analysis was performed by solving the mass and heat transport model equations using MATLAB software. The proposed research study promotes the application of VMD for recovering potable water from highly saline sea/brackish water and alleviates brine disposal issues. [ABSTRACT FROM AUTHOR]

Background and Objectives: Doxorubicin hydrochloride (DOX-HCl), a potent and extensively utilized anticancer medication, faces limitations in skin penetration, resulting in confined effectiveness. Frequent administration leads to resistance at the site of application. This study aims to strike a balance between precision and selectivity to enhance DOX-HCl's permeation. The goal is to achieve non-invasive drug delivery that avoids issues linked with conventional therapies. This will be achieved through the utilization of patches loaded with transfersomes for drug delivery. Materials and Methods: Transferosomes were prepared through the rotary evaporation technique and optimized by Box-Behnken experimental design. The impact of phospholipid, cholesterol, and tween-80 on drug entrapment efficiency and particle size was assessed using analysis of variance. The resulting formulations underwent characterization involving particle size, zeta potential, transmission electron microscopy, and Fourier-transform infrared spectroscopy. In addition, drug entrapment efficiency, in vitro drug release patterns, ex vivo drug permeation profiles, and histopathological evaluations of the optimized formulations were conducted. Results: The particle size ranged from 53 to 168 nm, with drug entrapment efficiency ranging from 30.8 ± 0.06 to 87.90 ± 0.02%. The optimum formulation exhibited a zeta potential of -24.9 mV and achieved an approximately fourfold increase in permeation rate compared to a pure drug suspension. Histopathological studies of rat abdominal skin samples post-treatment with transferosomes patch indicate a moderate epidermal inflammation versus normal morphology for untreated skin. Conclusion: Utilizing transferosomes in transdermal drug delivery systems (TDDS) presents a promising strategy to address challenges associated with conventional therapies. By incorporating transferosomes into patches, this approach offers a multi-faceted solution to enhance non-invasive drug delivery. [ABSTRACT FROM AUTHOR]

Anthropogenic particles (AP), which include microplastics and other synthetic, semisynthetic, and anthropogenically modified materials, are pollutants of concern in aquatic ecosystems worldwide. Rivers are important conduits and retention sites for AP, and time series data on the movement of these particles in lotic ecosystems are needed to assess the role of rivers in the global AP cycle. Much research assessing AP pollution extrapolates stream loads based on single time point measurements, but lotic ecosystems are highly variable over time (e.g., seasonality and storm events). The accuracy of models describing AP dynamics in rivers is constrained by the limited studies that examine how frequent changes in discharge drive particle retention and transport. This study addressed this knowledge gap by using automated, high‐resolution sampling to track AP concentrations and fluxes during multiple storm events in an urban river (Milwaukee River) and comparing these measurements to commonly monitored water quality metrics. AP concentrations and fluxes varied significantly across four storm events, highlighting the temporal variability of AP dynamics. When data from the sampling periods were pooled, there were increases in particle concentration and flux during the early phases of the storms, suggesting that floods may flush AP into the river and/or resuspend particles from the benthic zone. AP flux was closely linked to river discharge, suggesting large loads of AP are delivered downstream during storms. Unexpectedly, AP concentrations were not correlated with other simultaneously measured water quality metrics, including total suspended solids, fecal coliforms, chloride, nitrate, and sulfate, indicating that these metrics cannot be used to estimate AP. These data will contribute to more accurate models of particle dynamics in rivers and global plastic export to oceans. Practitioner Points: Anthropogenic particle (AP) concentrations and fluxes in an urban river varied across four storm events.AP concentrations and fluxes were the highest during the early phases of the storms.Storms increased AP transport downstream compared with baseflow.AP concentrations did not correlate with other water quality metrics during storms. [ABSTRACT FROM AUTHOR]

A hybrid technique is proposed in this manuscript for the optimal design of an induction motor (IM) drive for the dynamic load profiles during torque and flux control. The proposed hybrid method combines a Ladder-Spherical-Evolution-Search-Algorithm (LSE) and a recalling-enhanced recurrent-neural network (RERNN), which is called an LSE-RERNN technique. The major objective of the proposed method is to minimize IM losses while maintaining control over speed and torque. The proposed method effectively tunes the gain parameter of the PI controller for flux and torque regulation. The LSE methodgenerates a set of gain parameters optimally predicted by RERNN. The method reduces losses without prior knowledge of load profiles, achieving energy savings for steady-state optimum flux. The performance of the proposed technique is done in the MATLAB and is compared with different existing techniques. The value of the proposed method for the mean is 0.328, the standard deviation (SD) is 0.00334, and the median is 0.4173. The loss of the proposed method is much less than 0.3 W while compared to different existing approaches. Moreover, the computation time of the proposed approach is lesser than the existing techniques. • Optimal design of IM drive to control the torque and flux. • The proposed method is reducing the loss of IM. • LSE is utilized to generate the set of gain parameter. • The proposed technique is implemented in the MATLAB. • The computation time of the proposed method is lesser. [ABSTRACT FROM AUTHOR]

The unicellular calcareous planktic foraminifera sequester a significant portion of the carbon dioxide dissolved in the ocean, thus burying the carbon in sediments for millions of years. The global warming and associated processes are likely to affect the planktic foraminiferal abundance and diversity. Therefore, their baseline distribution has to be documented and correlated with ambient parameters to assess its fate under different climate change scenarios. Here, we report an exceptionally high abundance of planktic foraminifera and thus large carbon burial in the southwestern Bay of Bengal. The very high absolute abundance of planktic foraminifera in the Cauvery River basin is attributed to biannual productivity, warmer and saline waters. Globigerinita glutinata is the highest abundant species followed by Globigerinoides ruber and Globigerina bulloides. Globigerina bulloides is abundant on the shelf, where the upwelling is more frequent. The relative abundance of Globorotalia menardii is positively correlated with thermocline salinity and negatively correlated with thermocline temperature. Similarly, Neogloboquadrina dutertrei and Globoquadrina conglomerata are negatively correlated with mixed layer as well as thermocline temperature and mixed layer salinity. Both these species are positively correlated with thermocline salinity. Globigerina falconensis is more abundant in the southernmost transect influenced by intense winter monsoon precipitation. We report that G. ruber prefers high saline and warmer waters with the highest abundance in the southernmost transect. From the foraminiferal distribution, it is evident that the temperature and salinity of the mixed layer as well as thermocline, food availability, and monsoon-associated processes affect the planktic foraminiferal abundance and thus carbon burial in the southwestern Bay of Bengal. The changes in influx of southeastern Arabian Sea water will affect the planktic foraminiferal population and subsequent carbon burial in the southwestern Bay of Bengal. [ABSTRACT FROM AUTHOR]

One of the possible sources of carbon dioxide emission into the atmosphere can be river ecosystems. The paper presents the results of measuring CO2 fluxes from the surface of several rivers and lakes in Tomsk Region. In the experimental period, average carbon dioxide fluxes were 143.7 ± 21.7 (August 13–14, 2023), 53.3 ± 21.2 (August 19), and 80.4 ± 59.9 mgC m−2 h−1 for the Ob River; 66.1 ± 17.3 mgC m−2 h−1 for the Ket River; 33.3 ± 17.3 mgC m−2 h−1 for the swamp Karasevoye Lake, 50.2 ± 23.0 mgC m−2 h−1 for the Suiga River, and 81.9 ± 11.5 mgC m−2 h−1 for the Iksa River. The flux magnitudes significantly depended not only on the object of the study, but also on hydrometeorological conditions. [ABSTRACT FROM AUTHOR]

The effect of total solar eclipse on ionospheric total electron contents (TECs) over the ionospheric region of Indonesia was studied using GNSS-/GPS-based retrieved data. Continuous TEC analysis in conjunction with total solar eclipse of 09 March 2016 has been made from 08 to 10 March 2016 over Cibinong station of Indonesia sector (6° 28′ S, 106° 51′ E). Over Cibinong GNSS/GPS station of Indonesia, around ~ 94% of maximum obscurity of solar eclipse was observed. The eclipse event reached its maximum development at 00:58 UTC on 09 March 2016 with a magnitude (the fraction of the angular diameter of a celestial body being eclipsed) 1.045 and a duration of around 210 s (3 m 10 s). Results of the ionospheric vertical total electron contents during the total solar eclipse of 09 March 2016 over the Indonesian region were compared with the normal days. GNSS-/GPS-measured TEC over Cibinong of Indonesia was observed to be less than the pre- and post-eclipse days before the occurrence of total solar eclipse, but these were found to be more than the pre-eclipse day and less than the post-eclipse day after the occurrence of total solar eclipse of 09 March 2016. For both pre- and post-eclipse days, trend lines of proton temperature were found to have negative slopes, whereas a positively increasing trend line was observed on the eclipse day of 09 March 2016. The proton fluxes with energy (> 10 MeV) were found to show almost similar behavior on pre-, post-, and eclipse days of the study period. However, a small but positive constant slope was found on pre-eclipse day. [ABSTRACT FROM AUTHOR]

In accordance with the educational standards of the Federal State Educational Standard for Secondary Professional Education, it is intended to familiarize students of professional educational organizations with the properties of radioactive radiation, their practical applications, as well as with some concepts of dosimetry and protection from such radiation.The relevance of this research can be debated for a very long time. But in light of recent events it is obvious.A thorough mastery of all this material is impossible without studying the law of radioactive decay and the law of absorption of radiation.The research problem: the law of radioactive decay and the law of absorption of radiation are expressed using the exponential function N=N_0 e^(-λt) and i=Ie^(-μχ) and are usually not presented in the course of Physics in secondary specialized educational institutions. At best, an appropriate schedule is drawn, but without justification. It seems that this is caused by two reasons: firstly, when writing the exponent function, the base of natural logarithms is used – the number e, which is unknown to intermediate students; secondly, the above laws are usually derived by solving differential equations, which is far beyond the scope of the mathematics curriculum. Meanwhile, both of these difficulties can be easily overcome by using the properties of the exponential function known to students of secondary vocational education.The purpose of the research is to develop a methodology for deriving the law of radioactive decay and the law of radiation absorption, using the properties of the exponential function; to conduct a pedagogical experiment in order to identify the problem of students’ mastery of the proposed material.The research methods used are theoretical justification; calculation; comparison of quantities; graphical analysis of experimental data; generalization of the experimental factors of the study and their explanation.The research results: a methodology has been developed for deriving the law of radioactive decay and the law of radiation absorption using the property of the exponential function; the result of the pedagogical experiment confirmed the effectiveness of the developed methodology.Key conclusions: from the proposed article we can conclude that the presented method for deriving the law of radioactive decay and the law of absorption of radiation using the property of the exponent function can be used by teachers when studying the section «Radioactive Radiation» for both students of professional educational organizations and school students (advanced level).

Direct Contact Membrane Distillation (DCMD) uses low heat sources to separate water from urea, which was then used as a plasticizer in regolith-based cement to make it more workable. The work investigated separating potable water and urea from artificial urine using DCMD and then characterizing the products. Water was successfully separated from the artificial urine solution as characterized by density, conductivity, pH, and substance concentrations. The concentrated urine solution was used in regolith-based cement cured under vacuum at temperatures that simulated temperatures that would be expected in construction on the Moon. Workability and other properties were improved by replacing water with concentrated urine solution in the mix.