Total Molar Research Articles

Determination of Osmotic Flow in Water Transport in an Illitic Clay.

Experimental studies have shown that osmosis could be one of the mechanisms of water transport in porous materials that act, to a certain extent, as semipermeable membranes. In this paper, an experimental apparatus and the corresponding model to measure and determine the osmotic efficiency, σ, of bulk porous materials are described. Both the apparatus and model to interpret water transport in samples are modifications of those of Sherwood and Craster. In addition to σ, the transport parameters of the model include Darcy permeability and water and salt diffusivity. These parameters are used to calculate the ratio of the individual components of the total molar flow. We used the apparatus to measure cylindrical samples made from an illitic clay with a diameter of 45 mm and thickness of 5 mm. The measured transport coefficients were then used to estimate the relative importance of the individual contributions to the total flow of water through the samples. Our results show that the contribution of the osmosis is 82-88%, while the diffusion contributes only 11-13% and the Darcy flow caused by the pressure difference contributes only 1-5%. Even after considering the uncertainties in the measurement of the transport coefficients, which are estimated to be up to 22%, the results show that osmosis makes an important contribution to the total water flow and should not be neglected in general.

Regional Trends and Spatial Gradients of Total Column Methane over India, China, and USA─Implications for Emissions from Coal Mining and Oil/Gas Exploitation.

Observation-based verification of regional/national methane (CH4) emission trends is crucial for transparent monitoring and mitigation strategy planning. Although surface observations track the global and sub-hemispheric emission trends well, their sparse spatial coverage limits our ability to assess regional trends. Dense satellite observations complement surface observations, offering a valuable means to validate emission trends, especially in regions where emissions changes are substantial but debated. The uncertainty surrounding the rate of increase in fugitive coal mine emissions in China and emissions from unconventional oil and natural gas (ONG) exploration in the United States underscores the need for rigorous validation. Here, we examine the time evolution of total column dry-air mole fractions of CH4 (XCH4) during 2010-2020 by comparing observations from the GOSAT satellite with simulations from an atmospheric chemistry-transport model (ACTM). This study analyzes emissions and XCH4 trends in global totals and regions of India, China, the USA, and the global tropics. Our results suggest that GAINSv4 emission inventory overestimates the emission increase rate for the unconventional ONG sector of USA by about 3 times, while EDGARv6 inventory overestimates coal mine emissions in China. Emission increases in China and India agree with those estimated by GAINSv4. Analysis of spatially integrated XCH4 statistics (mean, 1-σ standard deviation) reveals a slight systematic underestimation of total emissions in China and bias (in both directions) in different parts of USA. Our results suggest that long-term satellite observations and ACTM simulations can effectively validate emission inventories for CH4 emissions and emission trends regionally.

Investigation of Alkaline Zinc Anode Performance with Increasing Addition of Calcium Zincate (Ca[Zn(OH)3]2·2H2o) Under Industrially Relevant Conditions

There is a need for safe, affordable, low cost, and reliable grid scale energy storage as the world transitions from fossil fuels towards intermittent renewable sources of energy. Metallic zinc (Zn) anodes are investigated and produced industrially for anodes for primary and rechargeable Zn batteries due to their high theoretical capacity, relative abundance, non-toxic, and non-flammable nature. Zn in alkaline electrolytes have poor reversibility at high Zn utilization due to passivation, shape change/redistribution, dendrite formation, hydrogen evolution, and the crossover of zincate ion (Zn(OH)4 2−) into the cathode. Zinc oxide (ZnO) anodes with additives such as calcium hydroxide (Ca(OH)2) have shown improvements on cyclability compared to metallic Zn anodes due to the in-situ formation of lower solubility calcium zincate (CaZn, (Ca[Zn(OH)3]2·2H2O)).Ex-situ synthesized CaZn has been cycled vs nickel under alkaline conditions showing great improvement in cyclability but to be economically feasible, it must be paired with MnO2 cathodes. Due to a charge in balance between the discharged CaZn and charged MnO2, practical anode recipes will include a higher percentage of charged Zn to prevent the requirement of additional formation steps. To understand how CaZn could be incorporated into commercial alkaline Zn/MnO2 batteries, anode formulations with increasing CaZn (0%, 30%, 70%, 100%) in mixtures with metallic Zn are investigated in 20 wt% KOH along with minor additions of Bi2O3, acetylene carbon, and CTAB surfactant. The total molar zinc content is normalized; thus, electrode capacity is kept comparable, resulting in electrodes relevant to real world use cases. At high 50% Zn utilization, pure CaZn anodes achieved ~280 cycles while Zn anodes achieved ~50 cycles, a five-time improvement in cycle life resulting in four times cost reduction per cycle. Not only do we compare cyclability of the different formulations but also compare the different failure mechanisms of the majority Zn with CaZn vs a pure CaZn anode to understand why there is an increase in the cycling performance.Acknowledgement: This work was supported by the U.S. Department of Energy Office of Electricity. Dr. Imre Gyuk, Director of Energy Storage Research at the U.S. Department of Energy Office of Electricity, is thanked for his financial support of this project. This work was performed, in part, at the Center for Integrated Nanotechnologies, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science. The views expressed in this article do not necessarily represent the views of the U.S. Department of Energy or the United States Government. This article has been authored by an employee of National Technology & Engineering Solutions of Sandia, LLC under Contract No. DE-NA0003525 with the U.S. Department of Energy (DOE). The National Technology & Engineering Solutions of Sandia, LLC employee owns all right, title and interest to their contribution to the article and is responsible for its contents. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this article or allow others to do so, for United States Government purposes. The DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan

Improving Bioactivity of Anodic Titanium Oxide (ATO) Layers with Chlorine Ion Addition in Electrolytes

Appending diverse quantities of additional elements to the anodizing solution leads to the formation of a highly corrosion-resistant and biocompatible anodic Ti oxide (ATO) on the titanium surface. This study aims to investigate the synergistic effect of chlorine and sulfate ions in the anodizing solution on the formation mechanism and biocompatibility of anodized layers formed on pure Ti. For this purpose, sulfuric acid-based anodizing solutions with different molar ratios () of 0.25, 0.5, and 0.75, and total molars () of 1, 1.5, and 2 M, were utilized for galvanostatic anodizing conditions at different current densities. The response surface methodology was employed on these three anodizing parameters to optimize the quality of anodic Ti oxide layers. Voltage vs. time behavior, SEM surface morphology, and FE-SEM fractured cross-sectional observations were used to thoroughly discuss the formation mechanism. X-ray diffraction method, micro-Raman spectroscopy, and water contact angle measurements were performed to characterize the coatings. Corrosion properties of ATO layers were evaluated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization in simulated body fluid (Hanks’ solution). The total molar () is recognized as the most influential factor on the anodic oxide layer properties, and a three-step formation mechanism, based on the competition between the formation and dissolution of anodic Ti oxide, was proposed in detail. The sample anodized with a molar ratio () of 0.5 at a constant current density of 70 mA.cm-2 and a total molar of 1.5 M achieved maximum corrosion resistance with a corrosion current density of 2.138e-11 A.cm-2 compares to 1.39e-8 A.cm-2 for the substrate. Furthermore, the addition of chloride ions to the anodizing bath resulted in more hydrophilic surfaces, promoting the formation of granular hydroxyapatite (HAp) on the TAO coating with maximum corrosion resistance in the Hank solution.

Machine Learning Elucidates Design Features of Plasmid Deoxyribonucleic Acid Lipid Nanoparticles for Cell Type-Preferential Transfection.

To broaden the accessibility of cell and gene therapies, it is essential to develop and optimize nonviral, cell type-preferential gene carriers such as lipid nanoparticles (LNPs). While high-throughput screening (HTS) approaches have proven effective in accelerating LNP discovery, they are often costly, labor-intensive, and do not consistently yield actionable design rules that direct screening efforts toward the most relevant chemical and formulation parameters. In this study, we employed a machine learning (ML) workflow, utilizing well-curated plasmid DNA LNP transfection data sets across six cell types, to extract compositional and chemical insights from HTS studies. Our approach achieved prediction errors averaging between 5 and 10%, depending on the cell type. By applying SHapley Additive exPlanations to our ML models, we uncovered key composition-function relationships that govern cell type-preferential LNP transfection efficiency. Notably, we identified consistent LNP composition parameters that enhance in vitro transfection efficiency across diverse cell types, including a helper lipid molar percentage of charged lipids between 9 and 50% and the inclusion of cationic/zwitterionic helper lipids. Additionally, several parameters were found to modulate cell type-preferentiality, such as the total molar percentage of ionizable and helper lipids, N/P ratio, PEGylated lipid molar percentage of uncharged lipids, and hydrophobicity of the helper lipid. This study leverages HTS of compositionally diverse LNP libraries combined with ML analysis to elucidate the interactions between lipid components in LNP formulations, providing insights that contribute to the design of LNP compositions tailored for cell type-preferential transfection.

Three-dimensional assessment on digital cast of spontaneous upper first molar distorotation after Ni-ti leaf springs expander and rapid maxillary expander: A two-centre randomized controlled trial.

The aim of this randomized controlled trial (RCT) was to evaluate the spontaneous distorotation of upper first permanent molars and the transverse dentoalveolar changes on digital casts in growing patients following maxillary expansion treatment using either the Leaf Expander® or the rapid maxillary expander (RME), both anchored to the deciduous second molar. This study was a two-arm, parallel-assignment, RCT with a dual-centre design conducted at two teaching hospitals in Italy. Inclusion criteria included maxillary transverse deficiency, prepubertal development stage (cervical vertebra maturation stage [CVMS] 1-2) and early mixed dentition with fully erupted upper first permanent molars. Exclusion criteria were systemic diseases or syndromes, CVMS 3-6, agenesis of upper second premolars, unavailability of the second deciduous molar for anchorage and Class III malocclusion. Patients were randomly assigned to the Leaf Expander® or RME group using a computer-generated randomization list created by a central randomization centre. Randomization was conducted immediately before the start of treatment. The intervention involved treatment with either the Leaf Expander® or the RME. Both devices were anchored to the second deciduous molars. Following randomization, patients were further categorized based on the presence of no crossbite, unilateral crossbite or bilateral crossbite. The primary outcome measure was the distorotation of the upper first molar (U6). Secondary outcomes included measurements of interdental linear dimensions, specifically upper inter-canine width (53-63), upper inter-molar width (MV16-MV26) and upper inter-deciduous second molar width (55-65). The examiner analysing the digital casts was blinded to the treatment groups to prevent detection bias and ensure objective assessment. However, due to the nature of the intervention, blinding was not feasible for the patients and clinicians involved in administering the treatment. A total of 150 patients were enrolled and randomly assigned to two groups: 75 to the Leaf Expander® group and 75 to the RME group. Recruitment started in November 2021 and was completed in November 2022. At the time of analysis, the trial was complete with no ongoing follow-ups. ANOVA tests revealed no significant differences between the three subgroups (no-cross, unilateral-cross and bilateral-cross) within both the Leaf Expander® and RME groups at T0. The Leaf Expander® demonstrated significantly greater distorotation in the unilateral crossbite subgroup compared to the RME (p = .014). In terms of total molar distorotation, the Leaf Expander® appliance showed a significantly greater effect (12.66°) compared with conventional RME (7.83°). Linear regression analysis demonstrated a significant correlation between the extent of expansion and the degree of molar rotation. Maxillary expansion resulted in significant spontaneous molar distorotation when the appliance was bonded to the second deciduous molars. The Leaf Expander® exhibited significantly greater molar distorotation compared with conventional RME. The degree of molar distorotation was correlated with the extent of expansion obtained on the second deciduous molar. The trial was registered at ClinicalTrials.gov (ID: NCT05135962).

Influence of Additional Intermediate Thick Al Layers on the Reaction Propagation and Heat Flow of Al/Ni Reactive Multilayers

This study investigates the effects of sputtering and electron beam evaporation (e‐beam) on the microstructure and reactive properties of Al/Ni reactive multilayers (RMLs). The intermixing zone, a critical factor influencing reaction kinetics, is characterized using high‐resolution transmission electron microscopy and found to be consistently 3 nm for both fabrication methods. Differential scanning calorimetry reveals that e‐beam samples, with thicker Al layers, exhibit slightly higher total molar enthalpy and maintain high reaction temperatures despite reduced reaction velocities in comparison to sputtered samples. X‐ray diffraction confirms the formation of both Al3Ni2and AlNi phases in the e‐beam samples. These findings indicate that while thicker bilayer structures reduce reaction velocity, they keep thermal output and mitigate the impact of intermixing zones, leading to similar total molar enthalpy. This analysis underscores the significance of deposition technique and bilayer thickness in optimizing the performance of Al/Ni RML, offering the possibility to establish different phase formations in thicker RML. It advances the control over the reactive properties of RMLs in their applications, for example, reactive bonding.

Перспективы использования баз спутниковых данных эмиссии парниковых газов при мониторинге объектов добывающей промышленности

Emissions of the greenhouse gases, particularly methane and carbon dioxide, by the mining, processing, and energy industries can significantly affect pollution in the bottom layer of the atmosphere, aerosols, and the atmospheric greenhouse effect. Continuous monitoring of emissions is the basis for developing effective strategies to reduce greenhouse gas emissions. Satellite missions are actively used for this purpose. The article provides an overview and description of the existing databases of greenhouse gas emissions obtained based on satellite measurements. The monitoring methodology involves satellite spectroscopy aimed at analyzing the spectral characteristics of light absorbed by the atmosphere. The results of measurements by satellite spectrometers show the total molar mass of substances throughout the atmospheric column. Global satellite monitoring allows identifying zones of anomalous concentration and identifying new sources of greenhouse gases, comparing them with the ground-based measurements of pollutants.

Improving nutrients ratio in class A biosolids through vivianite recovery: Insights from a wastewater resource recovery facility

Class A biosolids from water resource recovery facilities (WRRFs) are increasingly used as sustainable alternatives to synthetic fertilizers. However, the high phosphorus to nitrogen ratio in biosolids leads to a potential accumulation of phosphorus after repeated land applications. Extracting vivianite, an FeP mineral, prior to the final dewatering step in the biosolids treatment can reduce the P content in the resulting class A biosolids and achieve a P:N ratio closer to the 1:2 of synthetic fertilizers. Using ICP-MS, IC, UV–Vis colorimetric methods, Mössbauer spectroscopy, and SEM-EDX, a full-scale characterization of vivianite at the Blue Plains Advanced Wastewater Treatment Plant (AWTTP) was surveyed throughout the biosolids treatment train. Results showed that the vivianite-bound phosphorus in primary sludge thickening, before pre-dewatering, after thermal hydrolysis, and after anaerobic digestion corresponded to 8 %, 52 %, 40 %, and 49 % of the total phosphorus in the treatment influent. Similarly, the vivianite-bound iron concentration also corresponded to 8 %, 52 %, 40 %, and 49 % of the total iron present (from FeCl3 dosing), because the molar ratio between total iron and total incoming phosphorus was 1.5:1, which is the same stoichiometry of vivianite. Based on current P:N levels in the Class A biosolids at Blue Plains, a vivianite recovery target of 40 % to ideally 70 % is required in locations with high vivianite content to reach a P:N ratio in the resulting class A biosolid that matches synthetic fertilizers of 1:1.3 to 1:2, respectively. A financial analysis on recycling iron from the recovered vivianite had estimated that 14–25 % of Blue Plain's annual FeCl3 demand can potentially be met. Additionally, model simulations with Visual Minteq were used to evaluate the pre-treatment options that maximize vivianite recovery at different solids treatment train locations.

Sources of per- and polyfluoroalkyl substances in an arid, urban, wastewater-dominated watershed

Per- and polyfluoroalkyl substances (PFAS) enter surface waters from various sources such as wastewater treatment plants, fire-fighting sites, and PFAS-producing and PFAS-using industries. The Las Vegas Wash in Southern Nevada of the United States (U.S.) conveys wastewater effluent from the Las Vegas metropolitan area to Lake Mead, a drinking water source for millions of people in the U.S. Southwest. PFAS have previously been detected in the Las Vegas Wash, but PFAS sources were not identified. In this study, upstream wash tributaries, wastewater treatment effluents, and shallow groundwater wells were sampled in multiple campaigns during dry-weather conditions to investigate possible PFAS sources. Out of 19 PFAS, two short-chain PFAS—perfluoropentanoic acid (48 % of the total molar concentration) and perfluorohexanoic acid (32 %)—comprised the majority of PFAS loading measured in the Las Vegas Wash, followed by perfluorooctanoic acid (9 %). On a mass loading basis, the majority of total measured PFAS (approximately 90 %) and at least 48 % of each specific PFAS in the Las Vegas Wash likely entered via municipal wastewater effluents, of which the main source was likely residential wastewater. One of the drainage areas with a major civilian airport was identified as a potential source of relatively enriched perfluorosulfonic acids to a small wash tributary and shallow groundwater samples. Nonetheless, that tributary contributed at most 15 % of any specific PFAS to the mainstem of the Las Vegas Wash. Total PFAS concentrations were relatively low for the small tributary associated with an urban smaller airport and the lack of flow in the tributary channel immediately downgradient of an Air Force base indicates the smaller airport and base were unlikely significant PFAS sources to the Las Vegas Wash. Overall, this study demonstrated effective PFAS source investigation methodology and the importance of wastewater effluent as a PFAS environmental pathway.

Amphiphilic polymer Co-networks based on cross-linked tetra-PEG-b-PCL star block copolymers

A new class of AB4-type amphiphilic polymer co-networks (ACN) was prepared by hetero-complementary 2-(4-nitrophenyl)-benzoxazinone/amine end group cross-linking chemistry in dimethyl sulfoxide (DMSO). For this purpose, a well-defined star block copolymer (tetra-PEG-b-PCL) consisting of a hydrophilic tetra-arm PEG core (Mn ∼ 5 kg mol−1) and hydrophobic PCL wings with a total molar mass of Mn ∼ 10 kg mol−1 was synthesized by ring-opening polymerization (ROP). This tetra-PEG-b-PCL star block copolymer was functionalized either with 2-(4-nitrophenyl)-benzoxazinone or with amino terminal groups. The ACN synthesis was carried out by conversion of these two star block copolymers. The overlap concentration of c* ∼76 g L−1 determined by viscosity measurements of both stars showed no significant temperature dependence. The network syntheses carried out at different concentrations (0.5 c* to 2.5 c*) resulted in conversion degrees in the range of p ≈ 95 % or higher as detected by HR MAS NMR spectroscopy. As in previous work on the synthesis of A4B4 networks using the same cross-linking chemistry, deviations from the expected network structure (increased proportion of double links between two stars) were detected also here by multi quantum NMR spectroscopy. The expected environmentally sensitive behavior of the ACNs was confirmed in terms of their equilibrium swelling in solvents of different quality to PEG and PCL. The scaling of the swelling and viscoelasticity data as a function of preparation concentration showed deviations from the expectations of a perfectly cross-linked star polymer network. Finally, a two-step gelation process was observed by rheology at 30 °C in DMSO, which is related to associations between the 2-(4-nitrophenyl)-benzoxazinone groups surrounded by PCL blocks that become apparent on the time scale of rheology when the molar mass is increased as a result of cross-linking.

Stabilization of galactose oxidase by high hydrostatic pressure: Insights on the role of cavities size.

High hydrostatic pressure stabilized galactose oxidase (GaOx) at 70.0-80.0°C against thermal inactivation. The pseudo-first-order rate constant of inactivation kinact decreased by a factor of 8 at 80°C and by a factor of 44 at 72.5°C. The most pronounced effect of pressure was at the lowest studied temperature of 70.0°C with an activation volume of inactivation ΔV‡ of 78.8 cm3 mol-1. The optimal pressure against thermal inactivation was between 200 and 300 MPa. Unlike other enzymes, as temperature increased the ΔV‡ of inactivation decreased, and as pressure increased the activation energy of inactivation Eai increased. Combining the results for GaOx with earlier research on the pressure-induced stabilization of other enzymes suggests that ΔV‡ of inactivation correlates with the total molar volume of cavities larger than ~100 Å3 in enzyme monomers for enzymes near the optimal pH and whose thermal unfolding is not accompanied by oligomer dissociation.

Regulating lattice tensile strain of Ru-Co bimetallic nanoparticles on carbonized wood for boosting its hydrogen evolution reaction

The development of high-performance catalysts for hydrogen production originating from water electrolysis at the cathode is very crucial, but still a challenge. Here, trace Ru-doped Co bimetallic nanoparticles (named RuxCoy/CW-z, x/y and z represent the molar ratio and total molar content of metals) were in situ decorated on carbonized wood by the vacuum impregnation and high-temperature annealing method. Ru1Co10/CW-2 demonstrates good hydrogen evolution reaction (HER) intrinsic activity with the overpotential of −42 mV (at −10 mA/cm−2) and Tafel slope of 75 mV dec−1 in a 1.0 M KOH, indicating its favorable HER reaction kinetics, and Ru1Co10/CW-2 exhibits good stability for 100 h (at −50 mA/cm−2). The good performances of Ru1Co10/CW-2 can be ascribed to the adjustable lattice tensile strain and electronic interactions, while the porous carbonized wood promotes electron transfer, electrolyte transport and gas escape. This work combines the advantages of lattice tensile strain with self-supported porous carbonized wood for HER in alkaline solution, which provides a valuable reference for synthesizing carbonized wood electrode materials with very low Ru content.

Ocean-driven interannual variability in atmospheric CO2 quantified using OCO-2 observations and atmospheric transport simulations

Interannual variability (IAV) in the atmospheric CO2 growth rate is caused by variation in the balance between uptake by land and ocean and accumulation of anthropogenic emissions in the atmosphere. While variations in terrestrial fluxes are thought to drive most of the observed atmospheric CO2 IAV, the ability to characterize ocean impacts has been limited by the fact that most sites in the surface CO2 monitoring network are located on coasts or islands or within the continental interior. NASA’s Orbiting Carbon-Observatory 2 (OCO-2) mission has observed the atmospheric total column carbon dioxide mole fraction (XCO2) from space since September 2014. With a near-global coverage, this dataset provides a first opportunity to directly observe IAV in atmospheric CO2 over remote ocean regions. We assess the impact of ocean flux IAV on the OCO-2 record using atmospheric transport simulations with underlying gridded air-sea CO2 fluxes from observation-based products. We use three observation-based products to bracket the likely range of ocean air-sea flux contributions to XCO2 variability (over both land and ocean) within the GEOS-Chem atmospheric transport model. We find that the magnitude of XCO2 IAV generated by the whole ocean is between 0.08-0.12 ppm throughout the world. Depending on location and flux product, between 20-80% of the IAV in the simulations is caused by IAV in air-sea CO2 fluxes, with the remainder due to IAV in atmospheric winds, which modulate the atmospheric gradients that arise from climatological ocean fluxes. The Southern Hemisphere mid-latitudes and low-latitudes are the dominant ocean regions in generating the XCO2 IAV globally. The simulation results based on all three flux products show that even within the Northern Hemisphere atmosphere, Southern Hemisphere ocean fluxes are the dominant source of variability in XCO2. Nevertheless, the small magnitude of the air-sea flux impacts on XCO2 presents a substantial challenge for detection of ocean-driven IAV from OCO-2. Although the IAV amplitude arising from ocean fluxes and transport is 20 to 50% of the total observed XCO2 IAV amplitude of 0.4 to 1.6 ppm in the Southern Hemisphere and the tropics, ocean-driven IAV represents only 10% of the observed amplitude in the Northern Hemisphere. We find that for all three products, the simulated ocean-driven XCO2 IAV is weakly anti-correlated with OCO-2 observations, although these correlations are not statistically significant (p>0.05), suggesting that even over ocean basins, terrestrial IAV obscures the ocean signal.

Effects of Assisting Solvents on Purification Efficiency in the Layer Melt Crystallization of Glycerol.

The efficiency of layer melt crystallization for the selective separation of glycerol from a glycerol-diethylene glycol mixture containing 4 wt % of diethylene glycol was evaluated using solvent-free and solvent-aided approaches. The effect of 1-butanol and the binary solvent of 1-butanol and acetone with a total molar composition of 25 mol % on the crystal growth kinetics and the purity of the final product was studied at different undercooling degrees and crystallization yields. The melting point temperature of the mixtures was predicted by using the modified UNIFAC Dortmund model. The addition of both a single and binary solvents significantly increased the crystal growth rate and purity of the final product compared to crystallization from the solvent-free mixture. Additionally, higher crystal growth rates and product purity were observed in the binary solvent system compared to those in the single solvent system at the same degree of undercooling. The second stage of solvent-aided crystallization resulted in glycerol with a purity above 99.5 wt %, depending on the type of solvent used and the rate of crystal growth.

Synthesis and characterization of efficient Sr-doped ZnO nanostructures for optoelectronic, and photocatalytic applications

With increasing technological advancements, optoelectronics emergence is inevitable. Various metal oxides are explored for optoelectronics properties and Zinc oxide-based nanostructures have various advantages that can be explored in optoelectronic devices. Nanomaterials that are undoped and Strontium doped were synthesized via a simple wet chemistry route. The study set out to quantify the impact of Strontium doping in Zinc Oxide on optical and photocatalytic properties. The doping of strontium concentration within ZnO varied from 0 % to 3 % by weight of the total molar ratio. The characterization of SZO nanomaterials was done using measurements of X-ray diffraction, Raman Spectroscopy, SEM, Hall effect measurements, UV/Vis, and PL regarding their structural properties, morphological properties, optical properties, and electrical characteristics. X-ray diffraction analysis showed that the Sr-doped ZnO had the hexagonal wurtzite structure of zinc oxide. SEM showed that the morphology of Sr-doped ZnO thin films changed by increasing Sr concentration. Meanwhile, the film’s surface was smooth and crack-free. In UV–Vis experiments, the concentration of Sr doping reduced the optical band gap ranges from 3.27 eV to 2.98 eV. All the samples exhibited n-type conductivity in the Hall Effect. Photocatalytic degradation Methylene Blue was studied and SZO (3 at. %) was best for degradation with efficiency over 80 %.

LIBS analysis of tritium in thin film-type samples

Evaluating the mole fraction of hydrogen isotopes in a solid is a difficult task. Few methods allow it to be achieved. LIBS is a laser method based on the electronic excitation of elements and the spontaneous emission of characteristic optical lines. On a sample containing hydrogen isotopes, α-type lines can allow the estimate of their total mole fraction. In addition, LIBS is a discriminating method because it can separate the contributions of isotopes. This paper reports the implementation of this method on thin film-type samples containing hydrogen and tritium.They consist of nanometric layers of palladium and titanium on a silicon substrate. Under irradiation of nanosecond laser pulses reaching a fluence of the order of 200 J cm−2, LIBS was performed in argon at atmospheric pressure. A detailed spectroscopic study is performed around the Tα line of wavelength 656.039 nm of the Balmer series (n=3→2) of tritium. An analysis based on the reconstruction of the spectrum under conditions of local thermodynamic equilibrium is carried out. This leads to the estimate of the tritium mole fraction.

Effect of ammonia addition on nanostructure of soot in laminar coflow diffusion flames of ethylene diluted with nitrogen

The effect of ammonia addition on the nanostructure of soot particles was studied experimentally for ethylene diffusion flames. To compensate the thermal effect and nitrogen-containing species production when ammonia was added, the total mole fraction of ammonia and nitrogen was fixed in the fuel stream. Soot particle size, fringe length, and fringe tortuosity were measured through transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). A complementary X-ray photoelectron spectroscopy (XPS) analysis provided information about the chemical bonding of soot. A significant delay in soot growth was observed and the particle size increased with the addition of ammonia. While there was no obvious correlation between the fractal dimension of soot and ammonia mole fraction (XNH3) or sampling location. With the addition of ammonia, the mean fringe length increased reasonably linearly with XNH3 and the fringe tortuosity increased up to XNH3 ≈ 0.17 and then decreased with XNH3, which suggested that ammonia addition led to higher graphitization and lower oxidative activity. The soot from ammonia diluted flame exhibited lower reactivity, implying the delay of soot surface growth. With the addition of ammonia, the value of sp2/sp3 (indication of the graphitization degree of soot particles) did not change much for XNH3 from 0 to 0.17 then increased significantly, which indicated the degree of graphitization of soot particles significantly increased with ammonia addition. The intensity of the N1s peak (indication of the N-containing species in soot) increased with the addition of ammonia. This study confirmed that the addition of NH3 promotes the graphitization of soot.

Exopolysaccharides produced by Antrodia cinnamomea using microparticle-enhanced cultivation: Optimization, primary structure and antibacterial property

Microparticle-enhanced cultivation was used to enhance the production of exopolysaccharides (EPSs) from Antrodia cinnamomea. The structure and antibacterial activity of two EPSs produced by A. cinnamomea treated with Al2O3 [EPS-Al (crude) and EPS-Al-p (purified)] and without Al2O3 [EPS-C (crude) and EPS-C-p (purified)] were compared. It was observed that the addition of 4 g/L Al2O3 at 0 h resulted in the highest EPS yield of 1.46 g/L, possible attributed to the enhanced permeability of the cell membrane. The structural analysis revealed that EPS-C-p and EPS-Al-p had different structures. EPS-C-p was hyperbranched and spherical with a Mw of 10.8 kDa, while EPS-Al-p was irregular and linear with a Mw of 12.5 kDa. The proportion of Man in EPS-Al-p decreased, while those of Gal and Glc increased when compared to EPS-C-p. The total molar ratios of 6-Glcp and 4-Glcp in EPS-Al-p are 1.45 times that of EPS-C-p. Moreover, EPSs could alter bacterial cell morphology, causing intracellular substance leakage and growth inhibition, with EPS-Al having a stronger antibacterial activity than EPS-C. In conclusion, A. cinnamomea treated with Al2O3 could produce more EPSs, changing monosaccharide composition and glycosidic linkage profile, which could exert stronger antibacterial activity than that produced by untreated A. cinnamomea.

Treatment of food processing wastes for the production of medium chain fatty acids via chain elongation

The production of medium chain fatty acids (MCFAs) through reverse β-oxidation was investigated both on synthetic and real substrates. From preliminary batch tests emerged that caproic acid was maximized under an acetate/ethanol molar ratio of 5:1 at neutral pH. This ratio was then adopted in different semi-continuous tests operating with different amounts of the two reactants. It emerged that the MCFAs yield reached the maximum level of 6.7% when the total molar substrate amount was around 40–45 mmol/d, while the process was inhibited for values higher than 400 mmol/d. Semi-continuous tests using real waste as substrates, namely food waste condensate, cheese whey, and winery wastewater, confirmed the results obtained with the synthetic substrates. Better performances were obtained when an adequate molar ratio of the acetate and the electron-donor compound was naturally present. Therefore, a MCFAs yield of 25% and 10.5% was obtained for condensate of food waste and acidic cheese whey, respectively. Regarding MCFAs composition, caproic acid was the dominant form but small concentrations of octanoic acid were also found in the tests where ethanol was the electron donor (synthetic substrates and food waste condensate). Octanoic acid was not produced in test where lactic acid represented the electron donor molecules (cheese whey). Condensate and synthetic samples were dominated by Pseudoclavibacter caeni with an abundance of 38.19% and 33.38% respectively, while Thomasclavelia (24.13%) and Caproiciproducens (11.68%) was the most representative genus in acidic cheese whey sample.