Rapid Mass Research Articles

Mechanical insights into desulfurization by peroxymonosulfate oxidation via a non-reactive oxygen species pathway

Air pollution by sulfur dioxide (SO2) remains a pressing concern for both the environment and human health. Desulfurization enhanced by persulfate based advanced oxidation processes (PS-AOPs) has been proven to be a feasible method. However, the inherent contradiction between the rapid diffusion mass transfer of SO2 in the “gas-liquid-gas” phase and the limited lifespan of reactive oxygen species (ROS) can not be ignored. Excessive investment in PS is required to sustainably generate ROS to achieve continuous desulfurization performance, which may lead to excessive PS consumption. To address this issue, whether PS can achieve the oxidation absorption of SO2 via a non-reactive oxygen species pathway was investigated. Experimental and computational results demonstrated that peroxymonosulfate (PMS) instead of peroxydisulfate (PDS) had a great SO2 removal performance, the utilization of PS could be effectively achieved by maintaining a 1:1 molar ratio of PMS and removed SO2. The presence of HOO bonds in the PMS introduced a partial positive charge to the oxygen atom, making the PMS polar and more susceptible to be attacked by the nucleophile HSO3-. So SO2 underwent a series of processes including dissolution, dissociation, one-oxygen atom transfer, and ionization before ultimately being converted into SO42- ions, effectively achieving its removal from flue gas. This study may presents a novel approach for achieving high-efficiency flue gas desulfurization.

Three-dimensional N-doped graphene coated with B-doped iron phosphide electrocatalysts: Nonmetallic element co-modification for enhanced dual-pH hydrogen evolution reaction

The construction of cost-effective and highly active transition metal phosphide-based electrocatalysts instead of noble metals through a feasible strategy is crucial for addressing the energy crisis. Herein, a novel three-dimensional structure N-doped RGO coated with a ‘worm-like’ B-doped FeP electrocatalyst (B-FeP/N-RGO) was successfully developed using a multi-step reaction. The composite catalyst possesses a unique three-dimensional structure that facilitates rapid mass transfer, gas release and exposure of abundant active sites, and non-metallic element doping optimizes the electronic structure of the matrix, which together improve the hydrogen evolution reaction performance. Notably, the B-FeP/N-RGO catalysts can achieve a current density of 10 mA cm−2 in both acidic and alkaline electrolytes with overpotentials of only 125 and 176 mV, while maintaining long-term stability. This study offers a promising approach for designing and fabricating highly efficient three-dimensional electrocatalysts that do not rely on noble-metals and are suitable for a wide pH range.

Expansion of Accreting Main-sequence Stars during Rapid Mass Transfer

Accreting main-sequence stars expand significantly when the mass accretion timescale is much shorter than their thermal timescales. This occurs during mass transfer from an evolved giant star onto a main-sequence companion in a binary system and is an important phase in the formation of compact binaries including X-ray binaries, cataclysmic variables, and gravitational-wave sources. In this study, we compute 1D stellar models of main-sequence accretors with different initial masses and accretion rates. The calculations are used to derive semianalytical approximations to the maximum expansion radius. We assume that mass transfer remains fully conservative as long as the inflated accretor fits within its Roche lobe, leading stars to behave like hamsters, stuffing excess material behind their expanding cheeks. We suggest a physically motivated prescription for the mass growth of such “hamstars,” which can be used to determine mass-transfer efficiency in rapid binary population synthesis models. With this prescription, we estimate that progenitors of high-mass X-ray binaries and gravitational-wave sources may have experienced highly nonconservative mass transfer. In contrast, for low-mass accretors, the accretion timescale can exceed the thermal timescale by a larger factor without causing significant radial expansion.

Dual-Cation CuAgSe-Based Material: Rapid Mass Transfer in Synthesis and High Thermoelectric Performance Realization.

Understanding mass transfer mechanisms is vital for developing new material synthesis and densification technologies. Ion transport, serving both mass and charge transfer, is essential for the rapid preparation of high-performance fast ionic conductor thermoelectric materials like Zn4Sb3 and Cu2Q (Q = S, Se). In the case of dual-cation fast ion conductor materials like CuAgSe, exploring the relationship between cation transport becomes pertinent. In this study, copper (Cu) and selenium (Se) undergo a reaction in the presence of an electric field (∼15 A), resulting in the formation of the CuSe compound. Subsequent to this initial reaction, a subsequent thermal environment facilitates the interaction among Cu, CuSe, and Ag2Se, culminating in the rapid formation and densification of CuAgSe (with a relative density exceeding 99%) in just 30 s. Evidently, the diffusion of copper ions substantiates a pivotal role in facilitating mass transfer. As a result, CuAg1+xSe samples with different silver contents (x = 0.01, 0.02, 0.03, 0.04 and 0.05) can effectively inhibit cation vacancy, and introduce highly ordered Ag nanotwins to enhance the electrical transport performance. For CuAg1.04Se, a peak ZT value of 1.0 can be achieved at 673 K, which is comparable to the literatures. This work will guide the future electric field-assisted rapid mass transfer of materials.

Self‐Supported Electrocatalyst for Seawater Splitting

AbstractOver the past decades, tremendous effort has been made to enhance the water‐splitting via fabricating eco‐friendly electrocatalyst with increased conductivity, and large number of accessible active sites in lab scale. However, the development of earth abundant efficient electrocatalyst with superior activity for ‐seawater‐splitting remains a great challenge for the researchers. In this regard, self‐supported catalysts are found to be the most promising candidates, they have the features of increased loading, superior adhesion, rapid mass and charge transfer, and easy wettability for large scale hydrogen production via electrochemical seawater splitting. This review investigates different fabrication processes for the self‐supported catalyst, emphasizing their distinct characteristics that contribute to improved activity. Furthermore, we provided a detailed elucidation of the procedure and characteristics of seawater splitting, emphasizing the most recent progress in the creation of self‐supportive catalyst for the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and bifunctional activity. We have also examined the current barriers and potential prospects for advancing the utilization of self‐supported catalysts in the process of seawater splitting.

Development and Validation of a Rapid and Sensitive LC-APCI-MS/MS Method for the determination of three N-nitrosamine impurities in Varenicline tartrate drug substance and drug products

Nitrosamines impurities may be present in low levels in a variety of products that people are exposed to every day. After thorough investigations, regulatory agencies have outlined that the formation of nitrosamines is possible in the presence of secondary, tertiary, or quaternary amines and nitrite salts under acidic reaction conditions. For safety purpose, all API manufacturers must be developed methods to monitor the low levels of each nitrosamine impurity before the release the individual batches. In this article, we have developed novel, rapid and sensitive liquid chromatography Atmospiric pressure chemical ionization Mass spectroscopy (LC-APCI-MS/MS) method for the determination of N-Nitroso Dimethylamine (NDMA), N-Nitroso Diethylamine (NDEA) and N-Nitroso varenicline impurities in the Varenicline Tartrate drug substance and Drug products. Chromatographic separation is achieved using Inert sustain AQ C18 150 × 4.6mm, 3.0μ column with 0.1% formic acid in water as mobile phase A and 0.1% formic acid in methanol as mobile phase B at the 0.6 mL/min flow rate by using gradient mode of elution upto the 25 minutes total run time. The three impurities are successfully ionized and quantified in positive mode of atmospheric pressure chemical ionization (APCI) using multiple reaction monitoring (MRM). This method was validated according to ICH Q2 (R1) guidelines. The method provided excellent S/N ratios with a high linearity range of 0.66-19.88 ppm with respect to Varenicline Tartrate sample concentrations with a regression coefficient >0.995. The recovery for the method was established with a protocol of three-step sample preparation and was satisfactory within 85-115%. The determined LOQ (0.66 ppm) and LOD (0.22 ppm) values are very low with respect to sample concentration which shows the sensitivity Performance of the method. The method can be routinely applied for the detection of N-nitrosamine impurities (NDMA, NDEA and N-Nitroso varenicline) in Varenicline Tartrate drug substance and Drug products.

Multistep kinetics in self-induced sol–gel process of amorphous anhydride formation during thermal dehydration of potassium tetraborate tetrahydrate

AbstractThe physico-geometrical mechanism and kinetics of the multistep thermal dehydration of potassium tetraborate tetrahydrate was investigated as a model reaction to produce amorphous anhydrate via the self-induced sol–gel process. The thermal dehydration is composed of three consecutive dehydration steps: (1) a surface reaction in the solid-state accompanied by crack formation; (2) a rapid mass loss process accompanied by liquefaction to form the aggregate of the gel powders; and (3) the dehydration of gel powder aggregate to form a glassy anhydride. The changes in the contribution of the individual dehydration steps to the overall process according to the sample particle size and the heating rate (β) were identified as specific features of the multistep dehydration, which was characterized quantitatively using mathematical deconvolution analysis with log-normal four-parameter functions. The difficulty in determining the apparent activation energy (Ea) of the individual dehydration steps using isoconversional analysis due to the changes in the contribution depending on β values was addressed using modulated temperature thermogravimetry. Using the contributions and the apparent Ea of the individual dehydration steps as initial values, the kinetic description of the multistep thermal dehydration was refined through a kinetic deconvolution analysis using the cumulative kinetic equation. As a result, the individual dehydration steps were kinetically characterized as: (1) a surface reaction described by the first-order rate law with Ea,1 of approximately 68 kJ mol−1; (2) a reaction accompanied by liquefaction controlled by an autocatalytic rate behavior with Ea,2 of approximately 123 kJ mol−1; (3) a diffusion-controlled dehydration of gel powder with Ea,3 of approximately 82 kJ mol−1.

From Haute Couture to Fast Fashion: The Fashion Industry and its Implications in the Realm of Law

Although it is frequently treated casually, the fashion industry is in fact an all-pervasive and ubiquitous industry. The clothing industry is a vast global enterprise that deals with designing, manufacturing, distributing, marketing, retailing, advertising, and promoting all types of apparel for men, women, and children. This includes everything from high-end designer fashion to everyday clothing like sweatpants. The industry is worth billions of dollars and encompasses everything from the most luxurious haute couture to casual wear. The industry has thrived on its own through all the glitz and glamour. However, the blatant yet complex issues and nuances that comprise the industry need to be addressed, and in order for them to be addressed, consumers need to take cognizance of not just the present issues, but the industry in its entirety as well. This research paper delves into the transformation of the fashion industry from the traditional form of haute couture to the emergence of fast fashion. The paper starts by making the reader conscious of the industry and its alarming effects on various aspects of our society. The paper then discusses the rise of fast fashion, characterized by rapid production, mass consumption, and affordability. These diverging paradigms have not only transformed consumer behavior but have also posed legal challenges to frameworks governing intellectual property, labor rights, and environmental sustainability.

Porous MnxFe3-xO4 spinel oxides trigger H2O2 activation for boosted degradation of tetracycline: The formation and dominant role of surface-bound radicals

Traditional hydrogen peroxide (H2O2)-based advanced oxidation processes (AOPs) are limited by poor catalytic activity, low availability of radicals and severe matrix interference. Herein, a novel porous Mn1.1Fe1.9O4 was successfully synthesized via pores construction-Mn substitution regulation strategy for efficient H2O2 activation and tetracycline removal. The porous Mn1.1Fe1.9O4/H2O2 system achieved a highly efficient removal effect (k = 0.0585 min−1) toward tetracycline (40 mg/L), approximately 14.8 and 16.2 times higher than those of bulk Mn1.1Fe1.9O4 and porous Fe3O4, respectively. Distinct from conventional free radicals-dominated Fenton-like system, the developed surface-bound OH-dominated porous Mn1.1Fe1.9O4/H2O2 system could degrade the contaminants that adsorbed onto Mn1.1Fe1.9O4 surface, and displayed broad pH adaptability (3.0–9.0) and high anti-interference to inorganic ions, humic acid, and even real water matrixes. The density functional theory (DFT) calculations confirmed that dual Mn − Fe sites could co-adsorb H2O2 through a “bridge” mode to induce the in-situ generation of surface-bound OH, and Mn was the main active sites. Besides, the tailored porous structure offered a rapid mass transfer channel for continuously generating surface-bound OH and enhancing H2O2 utilization efficiency by shorting migration distance between active species and H2O2/pollutant. This work provided novel insights for the in-situ generation of surface-bound OH and the development of H2O2-based AOPs with fine anti-interference property.

Periodic vaccination for post-pandemic management: Insights from and planning beyond COVID-19

Waning immunity to the SARS-CoV-2 virus and the inevitability of viral mutations necessitate a large-scale periodic revaccination program. Rapid mass vaccination may quickly suppress an epidemic, but it may have an unintended downstream effect of creating a surge in population susceptibility later when vaccinated people lose their immunity all at the same time. To test this hypothesis, we conducted a simulation study comparing pulse vaccination, the repeated administration of “booster” vaccines in large pulses occurring at fixed intervals, and constant vaccination, the continuous administration of booster vaccines at a slower, constant pace. We showed that constant vaccination can maintain population susceptibility and therefore incident deaths at a constant, manageable level; while pulse vaccination can induce large recurrent epidemics. The advantage of constant vaccination is only realized, however, in a post-pandemic scenario when a high level of population immunity has already been attained through a combination of vaccination and natural infection. At the beginning of a novel pandemic, aggressive vaccination is recommended to prioritize immediate protection over long-term protection. In a counterfactual analysis, we showed that prematurely switching to constant vaccination would have significantly increased the disease burden during the Delta variant wave in August 2021.

Bimetal organic framework derived CoM@N–C composites as bifunctional oxygen catalysts for Zn-air batteries

Metal-loaded nitrogen-doped carbon (M@N–C) catalysts have shown promise as electrocatalysts for replacing noble metal catalysts in industrial processes. To study the influence on structural and performance caused by different bimetal doping, a family of bimetals CoM@N–C (M = Cu/Ni/Fe) composites with porous surface and abundant C defects were well-designed. After bimetallic doping, more defects are introduced into the carbon frameworks, and the metal-N species are fixed. As such, efficient utilization of active sites and rapid mass transfer make the reaction kinetics process more favorable and stable. Density functional theory calculations indicate that Cu/Ni doping optimizes the electronic environment of the Co–N, resulting in the balanced adsorption and dissociation of oxygen intermediates. While the synergy of FeCo activates the O=O, which promotes the sharp decrease in free energy of ∗OOH to ∗O, shifting the rate-determining step for oxygen reduction reaction. This indicates the adsorption site transfer of CoFe0.05@N–C in oxygen reduction and evolution reactions. The CoFe0.05@N–C catalyst exhibits superior bifunctional catalytic activity (with a potential gap of 0.80 V) than that of Pt catalysts. This work presents a simple strategy to fabricate well-defined bimetals doping in bifunctional oxygen electrocatalysts and it is expected to inspire future work on the role of electronic structure modulation and interface engineering.

Solar-Driven Multistage Device Integrating Dropwise Condensation and Guided Water Transport for Efficient Freshwater and Salt Collection.

Interfacial solar vapor generation (ISVG) is an emerging technology to alleviate the global freshwater crisis. However, high-cost, low freshwater collection rate, and salt-blockage issues significantly hinder the practical application of solar-driven desalination devices based on ISVG. Herein, with a low-cost copper plate (CP), nonwoven fabric (NWF), and insulating ethylene-vinyl acetate foam (EVA foam), a multistage device is elaborately fabricated for highly efficient simultaneous freshwater and salt collection. In the designed solar-driven device, a superhydrophobic copper plate (SH-CP) serves as the condensation layer, facilitating rapid mass and heat transfer through dropwise condensation. Moreover, the hydrophilic NWF is designed with rational hydrophobic zones and specific high-salinity solution outlets (Design-NWF) to act as the water evaporation layer and facilitate directional salt collection. As a result, the multistage evaporator with eight stages exhibits a high water collection rate of 2.25 kg m-2 h-1 under 1 sun irradiation. In addition, the desalination device based on the eight-stage evaporator obtains a water collection rate of 13.44 kg m-2 and a salt collection rate of 1.77 kg m-2 per day under natural irradiation. More importantly, it can maintain a steady production for 15 days without obvious performance decay. This bifunctional multistage device provides a feasible and efficient approach for simultaneous desalination and solute collection.

Rapid Characterization of Undeclared Pharmaceuticals in Herbal Preparations by Ambient Ionization Mass Spectrometry for Emergency Care.

In Asia, some herbal preparations have been found to be adulterated with undeclared synthetic medicines to increase their therapeutic efficiency. Many of these adulterants were found to be toxic when overdosed and have been documented to bring about severe, even life-threatening acute poisoning events. The objective of this study is to develop a rapid and sensitive ambient ionization mass spectrometric platform to characterize the undeclared toxic adulterated ingredients in herbal preparations. Several common adulterants were spiked into different herbal preparations and human sera to simulate the clinical conditions of acute poisoning. They were then sampled with a metallic probe and analyzed by the thermal desorption-electrospray ionization mass spectrometry. The experimental parameters including sensitivity, specificity, accuracy, and turnaround time were prudently optimized in this study. Since tedious and time-consuming pretreatment of the sample is unnecessary, the toxic adulterants could be characterized within 60 s. The results can help emergency physicians to make clinical judgments and prescribe appropriate antidotes or supportive treatment in a time-sensitive manner.

Development of a Robust, Rapid and Reliable Tandem Mass Spectrometry Method for the Measurement of Sildenafil, Bosentan and their Major Metabolites

Development of a Robust, Rapid and Reliable Tandem Mass Spectrometry Method for the Measurement of Sildenafil, Bosentan and their Major Metabolites

Confined growth of Ultrathin, nanometer-sized FeOOH/CoP heterojunction nanosheet arrays as efficient self-supported electrode for oxygen evolution reaction

Self-supported electrodes, featuring abundant active species and rapid mass transfer, are promising for practical applications in water electrolysis. However, constructing efficient self-supported electrodes with a strong affinity between the catalytic components and the substrate is of great challenge. In this study, by combining the ideas of in-situ construction and space-confined growth, we designed a novel self-supported FeOOH/cobalt phosphide (CoP) heterojunctions grown on a carefully modified commercial Ni foam (NF) with three-dimensional (3D) hierarchically porous Ni skeleton (FeOOH/CoP/3D NF). The specific porous structure of 3D NF directs the confined growth of FeOOH/CoP catalyst into ultra-thin and small-sized nanosheet arrays with abundant edge active sites. The active FeOOH/CoP component is stably anchored on the rough pore wall of 3D NF support, leading to superior stability and improved conductivity. These structural advantages contributed to a highly facilitated oxygen evolution reaction (OER) activity and enhanced durability of the FeOOH/CoP/3D NF electrode. Herein, the FeOOH/CoP/3D NF electrode afforded a low overpotential of 234 mV at 10 mA cm−2 (41 mV smaller than FeOOH/CoP grown on unmodified Ni foam) and high stability for over 90 h, which is among the top reported OER catalysts. Our study provides an effective idea and technique for the construction of active and robust self-supported electrodes for water electrolysis.

To achieve fast ion transport of engineered electrolyte and ultra-high rate of defected Nb16W5O55-based anode

The maximum output power and minimum charge time of a lithium-ion battery depend on ion transport and electron transport. The electron conduction/ion diffusion within the electrochemically active materials and the ion mobility of the electrolyte usually represent the fundamental limits of the battery charge and discharge rates. Nb16W5O55 is notable for its exceptional lithium-ion mobility and high electronic conductivity, making it a popular choice for fast-charging anode materials. However, the lithium-ion diffusion capability of the electrolyte is also crucial in determining the overall fast-charging performance of the battery. This can be a limiting factor for Nb16W5O55-based batteries. This work delves into the impact of electrolyte composition on fast-charging performance by examining the electrochemical properties of electrolytes with varying concentrations, in conjunction with molecular dynamics simulation. Specifically, increasing the concentration of LiTFSI salt alters the solvation structure of lithium ions due to the increasing coordination numbers of TFSI− and Li+, which hampers lithium-ion diffusion. Additionally, low-concentration electrolytes struggle with rapid mass transfer due to fewer lithium-ion carriers, limiting ultra-high-rate performance. To address these challenges, the solvation structure of the electrolyte was optimized, leading to enhanced fast-charging and discharging performance.

A regional early warning for slushflow hazard

Abstract. Slushflows are rapid mass movements of water-saturated snow. They release in gently sloping locations (<30°) and are hence not restricted to steep slopes. Slushflows are observed worldwide in areas with seasonal snow cover and pose a significant natural hazard in Norway. Hazard prediction and early warning are therefore crucial to prevent casualties and damage to infrastructure. A regional early warning for slushflow hazard was established in Norway in 2013–2014 as the first of its kind in the world. It has been operational since then. Four main variables are central in the methodology used: ground conditions, snow properties, air temperature, and water supply to snow. Gridded forecasting model simulations in the decision-making tool Varsom Xgeo, real-time data from automatic stations, and field observations from the field are assessed. Based on data from historical slushflows, a water supply–snow depth by snow type ratio has been developed as an assessment tool. This approach can be implemented in other areas with slushflow hazard where the necessary input data are available.

Simultaneous determination of folic acid photolysis products and oxidized guanine derivatives in plasma by liquid chromatography-tandem mass spectrometry.

Folic acid (FA) is easily photodegraded to yield 6-formylpterin and pterin-6-carboxylic acid, which can generate reactive oxygen species and result in the formation of oxidized guanine derivatives such as 8-hydroxy-2'-deoxyguanosine and 8-hydroxy-guanosine.In this study, we developed a simple, rapid, and sensitive liquid chromatography-tandem mass spectrometry strategy for the simultaneous determination of FA photolysis products and oxidized guanine derivatives in plasma samples. Chromatographic separation was performed on a Waters HSS T3 column (2.1 × 100mm, 5.0μm) with gradient elution at a flow rate of 0.25mL/min. Plasma samples were first pretreated with 1% formic acid, followed by protein precipitation with methanol. The developed method showed good linear relationships between 1 and 2000ng/mL (r2>0.99). The intra- and inter-day precisions ranged from 2.6% to 7.5% and from 2.5% to 6.5%, respectively. Recoveries of the analytes were between 75.4% and 112.4% with the relative standard deviation<9.1%. Finally, the method was applied to quantify FA photolysis products and oxidized guanine derivatives in rats with light and non-light conditions.

Enhanced structural stability of yttria‐stabilized zirconia–LaMgAl11O19 dual ceramic coating by an α‐Al2O3 layer

AbstractTo prolong the service life and structural stability of CoCrNiAlY–yttria stabilized zirconia–LaMgAl11O19 (LaMA) dual ceramic coating during high temperature exposure, an AlY plating layer was deposited on top LaMA. Results revealed that this coating without AlY plating layer showed a rapid mass increase from 6.62 mg/cm2 at 20 h to 10.63 mg/cm2 at 80 h, but also suffered from a fast TGO growth and severe elemental diffusion, resulting in an exacerbating interface fracture of the coating. However, AlY plating layer was first oxidized, and Y2O3 induced the formation of a dense α‐Al2O3 reaction layer on the top LaMA layer, which greatly prevented the internal penetration of O2. This coating with AlY plating layer showed a relatively stable structure, a very slow TGO growth, and a slight mass increase trend from 8.19 mg/cm2 at 20 h to 8.73 mg/cm2 at 80 h. Potential oxidation damage mechanisms of the coatings with or without AlY plating layer were comprehensively clarified.

Enhancing Urban Tunnelling Efficiency Through Real-Time Geotechnical Parameter Analysis, A Case Study at Kolkata East West Metro Project, KMRCL-1674

The exponential increase in urbanization has heightened the demand for a systematic and rapid mass transportation system in developing countries. One efficient solution has been the construction of underground networks of tunnels using Tunnel Boring Machines (TBMs). Urban tunnels, however, require careful attention to minimizing ground disturbances to avoid adverse impacts on existing infrastructure. The current study focuses on a parametric investigation based on observed trends from the Kolkata East West Metro UG1 project. It undertakes numerical regression to establish correlations, aiming to investigate geotechnical parameters derived from observed operational parameters during tunnel advancement. This correlation allows for the determination and validation of considered geotechnical parameters in real-time, thereby facilitating the optimization of operational parameters. By establishing correlations, the study examines and validates the effect of geotechnical parameters on observed settlement. In conclusion, the consideration of tunnel operational parameters and subsequent establishment of geotechnical parameters can potentially automate the functioning of mechanized tunnelling, leading to more efficient and effective tunnel construction processes.