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There is no intervention that quickly reduces a person's blood alcohol content (BAC). "Sober up before you drive" may prevent road traffic injury (RTI) caused by alcohol consumption. The aim of this study was to analyze the risk of RTI on an hourly basis (1–6 h) after the last drink and the determinants of this risk. This was a case-crossover study of alcohol consumption among 430 patients who suffered an RTI and arrived at an emergency department in a large hospital in Mexico City from January to April 2022. Of the 430 patients studied, 46 reported drinking within 1 h before the RTI, for a risk ratio (RR) of 7.7 (95% CI [5.6, 10.4]). This RR decreased to 2.2 (95% CI [1.3, 3.7]) for the 12 patients drinking in the second hour before the RTI and was null for those drinking earlier (p ≤ 0.001 for the trend). The induction time was 3 h among those with higher BAC and intoxication levels. The RR for an RTI decreases 71% from the first to second hour from the last drink and 32% from the second to third hour. This decrease was similar among those intoxicated and those with increased BACs. In multiple regression models, higher levels of intoxication and higher BACs remained associated with higher RRs. People should avoid driving after drinking. Waiting to drive, walking, or riding after drinking reduces the risk of an RTI, especially for people with higher BAC and intoxication levels. • The risk of TRI was higher 1 h after the last drink and decreased thereafter. • Risk was similar for drivers, pedestrians, and passengers. • The induction time was 1–2 h, extended for those with high BAC or intoxication. • Elevated risk depended on BAC at hospital entry and feeling intoxicated at injury. [ABSTRACT FROM AUTHOR]

Our aim was to analyze anesthetic induction time and postoperative pain using spinal anesthesia versus general anesthesia with or without the use of peripheral nerve blocks (PNBs) in total knee arthroplasty. The hypothesis was that spinal anesthesia would be beneficial with respect to induction time and postoperative pain and that PNBs would complement this effect. Patients were stratified according to demographics, American Society of Anesthesiologists physical status classification system (ASA), and opioid intake and divided into: (A) general anesthesia without PNB; (B) general anesthesia with PNB; (C) spinal anesthesia without PNB; and (D) spinal anesthesia with PNB. Endpoints were anesthetic induction time, opioid consumption, and pain. Of 559 patients, 348 (62.3%) received general anesthesia (consisting of group A with 46 and group B with 302 patients), and 211 (37.7%) spinal anesthesia (consisting of group C with 117 and group D with 94 patients). We observed significantly lower total opioid intake 48 hours postoperative when applying spinal anesthesia by 2.08 mg (P <.05) of intravenous morphine-equivalent, and a reduction of 7.0 minutes (P <.05) until skin incision. The application of a PNB achieved a reduction of piritramide intake of 3.59 mg (P <.05) 48 hours postoperative and lengthened induction time by 8.5 minutes (P <. 0 5). Statistically shorter anesthetic induction times without clinical relevance, but lower postoperative opioid dosages with clinical relevance were observed for patients undergoing total knee arthroplasty with spinal anesthesia. The additional application of PNBs led to a lower need for opioids and lower pain levels in the early postoperative phase. [ABSTRACT FROM AUTHOR]

Crude oil droplets in oilfield-produced water are highly emulsified, and the poor attachment between gas bubbles and oil droplets limits the effectiveness of oil-water separation during flotation processes. This paper proposes a new surface-functionalized bubble called a condensate bubble and evaluates its flotation performance based on surface properties and adhesion theory mechanism to address this issue. The surface chemical properties of the oil droplets were characterized using X-ray photoelectron spectroscopy (XPS), contact angle measurement, and zeta potential. Induction time and flotation tests were conducted to compare the attachment effects between air or condensate bubbles and emulsified oil droplets. The interaction forces were calculated using DLVO and extended DLVO theory. The experimental results showed that crude oil contains functional compounds containing oxygen that make it tough to float. However, the contact angle between the oil surface and condensate bubble was greater than 150°, demonstrating that the condensate liquid bubbles have better hydrophobicity than air bubbles. The micro-flotation experiments indicated that condensate bubbles have a strong collection capacity for emulsified oil droplets, which was confirmed by induction time tests. In 70 mM NaCl brine, the oil removal efficiency of condensate bubble flotation could reach 82%, which was a 30% improvement compared to air bubble flotation. However, DLVO theory failed to predict the flotation with a concentration higher than 10 mM NaCl. The extended DLVO theory accounted for hydrophobic interactions, which were observed due to similar solvent extraction and hydrophobicity of the condensate liquid film. As a result, the condensate bubble-oil droplet system exhibited stronger hydrophobic attraction, successfully confirming and illustrating the superiority of the condensate bubble in flotation. [Display omitted] [ABSTRACT FROM AUTHOR]

At a later stage of oilfield development, there will be more free water in the pipeline, which may engender the phase inversion of water-in-oil emulsions, thereby augmenting the risk of hydrate plugging. In a novel 30 L high-pressure autoclave, the effects of wax content, water cut, temperature, initial pressure, and rotation speed on hydrate crystallization nucleation and slurry viscosity were examined. Results demonstrated that in systems with wax content greater than or equal to 2 wt%, at the onset of the swift hydrate growth stage, the aggregation of wax and hydrate will impair the gelling structure of wax-containing oil, inducing an abrupt fall in slurry viscosity. Consideration is given to the solubility fluctuation of the natural gas in oil, and an empirical prediction formula for gas consumption during hydrate formation in wax-containing systems is established. The presence of wax hinders the crystalline nucleation and growth of hydrates. Notwithstanding, the hydrate slurry viscosity of the wax-containing system is greater because the wax-hydrate aggregates have a more conspicuous effect on the slurry viscosity than the hydrate volume fraction. The water cut of 70% is a critical upper limit, above which the viscosity of hydrate slurry would increase dramatically. Higher rotation speed and initial pressure can significantly enhance the viscosity of hydrate slurries, but their effects on the hydrate nucleation induction time are more perplexing. [Display omitted] • The kinetics of NGH formation in non-emulsifying oil system was analyzed. • The aggregation of wax and hydrate can destroy the gelling structure of the system. • Prediction of gas consumption during hydrate formation in wax-containing systems. • The effect of wax-hydrate aggregates on viscosity of NGH slurry is significant. [ABSTRACT FROM AUTHOR]

[Display omitted] • Promotion effect of Mg, Al and Zn plate on methane hydrate nucleation is determined. • The synergistic promotion effect of acid condition and metal plate is proposed. • Two nucleation modes are observed in metal plate systems with pure water and acid condition. • Methane-liquid–metal interface plays a vital role on accelarating hydrate nucleation. • The promotion effect is closely related to surface topography and hydrophilicity of metal plate. Hydrate-based technologies hold significant promise in the fields of gas storage, water desalination and gas separation, but their application is restricted by the long induction time and high degree of randomness associated with hydrate nucleation. In this study, we conducted experimental investigations to access the influence of metal plates (Mg, Al and Zn) on methane hydrate nucleation under both pure water and acidic conditions. The results demonstrated that Mg plate exhibited the strongest promotion effect on methane hydrate nucleation. The presence of acid significantly accelerated hydrate nucleation in the Zn plate system, but conversely reduced the promotion effect of Al plate. In conjunction with the in-situ morphology evolution of hydrate nucleation, methane-liquid–metal interface was found to play a crucial role in the metal-induced promotion effect. Two nucleation modes were proposed accordingly: (i) in pure water, hydrate nucleation initiated exclusively at the methane-liquid–metal interface without extra nucleation site (Mode 1), and (ii) in acidic condition, hydrate nucleation occurred with evident multiple nucleation sites (Mode 2). Furthermore, SEM imaging, AFM and contact angle characterization revealed that the surface properties of metal plate (e.g., hydrophilicity and roughness) were the key factors in determining the effectiveness of the promotion effect. Liquid climbing upward along the metal plate surface was vital for metal plates to promote gas hydrate formation. Overall, this study provides new insights into hydrate nucleation promotion and suggests a straightforward way to enhance hydrate nucleation by modifying surface properties. [ABSTRACT FROM AUTHOR]

This study introduced differential photocalorimetry (DPC) as a method for real-time monitoring of the photo-oxidation kinetics of vegetable oils. DPC measures the heat flow generated during the oxidation of oils upon light exposure. Experiments conducted with stripped linseed oil (SLSO), an oil depleted from its natural antioxidants, showed no induction time (τ). Conversely, spiking SLSO with increasing concentrations of trans -ferulic acid resulted in an induction time (τ) proportional to the antioxidant concentration (R2 = 0.99). A comparative study among different vegetable oils revealed that rice bran oil exhibited the highest resistant to photo-oxidation, followed by corn, soybean, and sunflower oils. The results are discussed in terms of sample oxidizability and antioxidant efficiency (A.E.), and validated through high-performance liquid chromatography with diode array detection (HPLC-DAD). Furthermore, the measured heat flow enabled the determination of the rates of inhibited (R inh) and uninhibited (R uni) periods, as well as the rate constant of propagation (k p) and inhibition (k inh) reactions. [Display omitted] • DPC allowed real-time monitoring of oil photo-oxidation kinetics. • An increase of the light intensity showed a consistent decrease in induction time. • DPC enabled determination of antioxidant efficiency, capacity and oil oxidizability. [ABSTRACT FROM AUTHOR]

• The dual effect of rhamnolipid on hydrate formation is due to the water structure. • The strongly hydrogen-bonded water inhibits nucleation but promotes growth. • Montmorillonite-induced adsorption is favorable for hydrate nucleation. Chemical additives play an important role in gas hydrate formation, which involves the transformation of water structure. However, the relationship between the effects of additives on water structure and hydrate formation is inconclusive, especially for amphiphilic molecules. Here, we investigate the changes in water structure caused by rhamnolipid (Rha) biosurfactants and the resulting effect on methane hydrate formation through kinetic experiments, morphological observation, and in situ Raman spectroscopy. The Gaussian peaks of strongly hydrogen-bonded and weakly hydrogen-bonded water are identified, of which the integrated intensity and position are compared. It is found that the dual effect of Rha on hydrate formation kinetics, namely nucleation inhibition and growth promotion, is attributed to the ordered arrangement of water molecules with stronger hydrogen bonding interactions induced by the charged head groups. The strongly hydrogen-bonded water inhibits nucleation but promotes growth. In addition, the adsorption of Rha on montmorillonite (MMT) eliminates the changes in water structure and the dual effect of hydrate formation kinetics, providing further evidence for the above conclusion. These insights pave the way for a deeper understanding of hydrate formation kinetics from a water structure perspective, as well as providing a scientific basis for the commercial application of surfactants. [ABSTRACT FROM AUTHOR]

[Display omitted] • The hydrophilic chain length of surfactant affects the kinetics of hydrate formation. • Surfactants improve the scatter of the induction time of hydrate formation and hydrate production. • The emulsion stability affects the promoting effect of surfactants on hydrate formation. • LAE-9 has the most effective on improving hydrate formation. To address the problems of slow crystallization and nucleation in two-phase miscibility in the application of refrigerant hydrates, adding surfactants can be taken as an effective way to promote hydrate formation. Three kinds of polyoxyethylene laurate (LAE) surfactant with different hydrophilic chain lengths (LAE-4, LAE-9 and LAE-24) were selected as accelerators to study their effects on hydrate formation. LAE series surfactants significantly reduce hydrate nucleation induction time. The hydrate induction time of the system with 4.0 wt% LAE-9 is shortest (98 min). The hydrate formation with 4.0 wt% LAE-9 has small randomness and is more stable. Micelles formed by LAE surfactants provide more nucleation sites and accelerate hydrate growth. The hydrate cold storage density is related to the hydrophilic chain length of surfactant. The system with 4.0 wt% LAE-9, which has a suitable hydrophilic chain length, achieves the largest hydrate cold storage density (246.10 kJ·kg−1). Hydrate has the fastest growth rate of 4.80 kJ·kg−1·min−1 in the system with 2.0 wt% LAE-24. There is a "memory" effect during hydrate formation and dissociation cycle, eliminating the need for induction time during hydrate re-formation. Hydrate can be re-formed quickly. [ABSTRACT FROM AUTHOR]

• An integral model was developed to determine the nucleation parameters. • A temperature-dependent function of interfacial energy was proposed. • A temperature-dependent pre-exponential factor inversely proportional to the solution viscosity was adopted. • The metastable zone width data of phenacetin in ethanol were analyzed. By incorporating a temperature-dependent function of interfacial energy and a temperature-dependent pre-exponential factor inversely proportional to the solution viscosity, an integral model was developed according to classical nucleation theory to retrieve the nucleation parameters from the metastable zone width (MSZW) data. The developed model was applied to determine the temperature-dependent interfacial energy and pre-exponential factor during the cooling process from the MSZW data for phenacetin in ethanol experimentally measured in this work. For comparison, the interfacial energy and pre-exponential factor for phenacetin in ethanol at various operating temperatures were determined from the induction time data based on the conventional method. The results indicated that the temperature-dependent interfacial energy and pre-exponential factor for phenacetin in ethanol obtained from the MSZW data based on the developed model were consistent with those obtained from the induction time data based on the conventional method. [ABSTRACT FROM AUTHOR]

The eye-glass polishing wastewater (EGPW) is an increasingly noteworthy problem because of its high chemical oxygen demand (COD), high turbidity and abundant microplastics (MPs), which threatens the aquatic environment as well as human life. In this study, we analyzed the separation performance of MPs from EGPW using sec-octyl alcohol and diesel oil as frother and collector, respectively. The experimental results demonstrated that the removal rate of MPs, COD and turbidity could reach to 93.9 %, 80.4 %, 83.8 %, respectively. The measurement of induction time, Fourier-transform infrared and X-ray photoelectron spectroscopy were measured to explain flotation mechanism of MPs. Sec-octyl alcohol has little effect on the functional groups of MPs and it mainly reduces the surface tension of gas-liquid interface and improves the stability of bubble. Diesel oil increases the C-C/C-H content of MPs, illustrating that it could absorb on the surface of MPs and improve the hydrophobicity of MPs. The induction time decreases with the increasing dosage of both sec-octyl alcohol and diesel oil, thus improving the separation rate of MPs from the EGPW. These results indicate that bubble flotation exhibits great potential to effectively remove MPs and purify the EGPW, anticipating to facilitate the municipal wastewater management. [ABSTRACT FROM AUTHOR]

• Effects of boundary layer and bulk crystalliser mixing on crystallisation kinetics are described. • Increased boundary layer mixing (Re) increases nucleation rate which reduces crystal size. • Higher bulk agitation (N) reduces induction time and increases crystal growth rate. • High supersaturation levels at increased Re promotes secondary nucleation and agglomeration. • Nucleation and crystal growth kinetics can be decoupled and independently controlled. While mixing is considered critical in membrane distillation crystallisation, an explicit link between mixing and crystallisation mechanisms has yet to be made. This study therefore used in-line nucleation detection to determine induction time and metastable zone width, as a method to characterise the independent roles of interfacial boundary layer mixing and bulk crystalliser mixing on the kinetics of nucleation and crystal growth in membrane distillation crystallisation. Interfacial boundary layer mixing was investigated by changing Reynolds number (Re , 1300–2050), where an increase in Re also increased flux. This increased supersaturation within the boundary layer, shortened induction time, and was correlated to a higher nucleation rate. The high nucleation rates introduced smaller crystal sizes, which is an effect that can be correlated to classical nucleation theory. Mixing within the crystalliser did not modify the interfacial supersaturation at nucleation (Re N 1562–18741). However, a decrease in induction time was observed when transitioning from lower to higher mixing, which may arise from the improved distribution of the supersaturated feed within the crystalliser. The effect of crystalliser mixing was also evident on crystal growth, where larger crystals were produced at higher crystalliser stirrer speeds due to improved diffusion-controlled growth. This study therefore demonstrates that bulk and interfacial mixing can be collectively used to control crystallisation by decoupling conditions that determine nucleation and crystal growth. Morphological assessment was subsequently undertaken that evidenced how dendritic breeding and wider secondary nucleation mechanisms that dominate crystal growth at high levels of supersaturation can be mitigated through mixing. Membrane crystallisation offers a scalable geometry in which we demonstrate mixing to facilitate good control over crystal growth which is more difficult to realise in existing evaporative crystalliser design. [ABSTRACT FROM AUTHOR]

Low flotation efficiency is the result of poor adhesion between oil droplets and air bubbles. The flotation of emulsified oil droplets can be improved by using bubbles coated with condensate. This study investigated the dynamic process of air/condensate bubble-oil droplet adhesion flotation and the flotation kinetic properties through experiments and theoretical models. The results show that the rupture of condensation bubbles with extraction effect is completed at 50/28 ms after collision with hydrophilic/hydrophobic oil droplets, and the oil droplets wrapped entirely on the surface of the condensate bubbles. In contrast, hydrophilic/hydrophobic oil droplets have a long liquid film thinning time (92/60 ms) after collision with air bubbles and form partially wrapped oil lenses after rupture. A modified Yoon-Luttrell model was suggested to clarify the relationship between bubbles and oil droplets. Finally, the flotation kinetic constant and induction time were calculated by the classical first-order kinetic model and the Finch model, respectively, and a fit was made to the relationship between the flotation rate constant, adhesion probability, and induction time(R2>0.95). It provides an important theoretical basis for further optimisation of the condensate bubble flotation process. [Display omitted] • Quantifying differences in adhesion of oil droplets to air /condensate bubbles. • Condensate bubbles improved hydrophilic/hydrophobic droplet capture. • The collision and adhesion models predicted the experimental data well. • A first-order kinetic model was used to back-calculate the induction time. [ABSTRACT FROM AUTHOR]

CO 2 gas hydrates occur in aqueous systems at elevated pressure and low temperature. They offer prospect to energy efficiency and gentle concentration of liquid foods. In current research, the formation of CO 2 gas hydrates in a batch autoclave system for pure water and pure coffee (13–40 wt%) was investigated. Hydrate formation was highly reproducible. When reducing the temperature from 4 to 1 °C, induction times in 13 wt% coffee solutions approached zero, regardless of the applied target pressure (36 vs. 41 bar). Over the used range of temperature, pressure and concentration, different gas hydrate morphologies could be observed, ranging from dispersed gas hydrate crystals in coffee slurry to ordered, large-scale structures. The formation of large continuous hydrate structures bears application potential for efficient removal of gas hydrates from the concentrated liquid. [Display omitted] • CO 2 gas hydrate formation can be triggered in coffee solutions. • Decreasing temperature and increasing pressure leads to shorter induction times. • Increasing the coffee concentration leads to a retardation in gas hydrate formation. • Depending on process conditions, various gas hydrate morphologies can be observed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Systematic study of nucleation behaviors of p-CA from induction time and MSZW. • Nucleation process corrected by CNT, self-consistent Nývlt-like and modified Sangwal's models. • Nucleation tendency in different solvents analyzed by nucleation parameters. • Solute-solvent interactions during nucleation simulated by MEPs, HS surface and RDF. The study of nucleation behaviors during crystallization is important for understanding the drug crystallization process. The induction time of p-coumaric acid (p-CA) was measured in four solvents at various levels of supersaturation. The kinetic parameters of nucleation (interfacial energy, critical nucleation radius, and critical Gibbs free energy) were estimated using the classical nucleation theory (CNT). The results showed that the nucleation difficulty of p-CA in the four solvents was in the order of ethyl acetate > acetone > ethanol > methanol. In addition, the metastable zone width (MSZW) of p-CA was determined in four solvents. The nucleation behaviors of p-CA were further expounded using self-consistent Nývlt-like model and modified Sangwal's model. The results were consistent with those of CNT. To further reveal the impact of interactions between solvent and solute molecules on the nucleation behaviors of p-CA, molecular electrostatic potential surfaces (MEPs), Hirshfeld Surfaces (HS), and the radial distribution function (RDF) were performed. The investigation revealed that the intensity of solvent–solute interactions depended primarily on the strength of hydrogen bonding interactions. The RDF results showed that the magnitude of hydrogen bonding interactions of p-CA in the four solvents was in the following order: ethyl acetate > acetone > ethanol > methanol. As the hydrogen bonding interactions between p-CA and solvent molecules became stronger, the dissociation of solute molecules from solvent molecules became more difficult, leading to a wider MSZW and a lower nucleation rate. [ABSTRACT FROM AUTHOR]

Hydrogen evolution and hydration kinetics of aluminum-particle-water reaction are investigated by a series of isothermal experiments. Morphology development of the Al particle during the hydration reaction process is characterized by SEM and XRD. An improved multi-stage analytical model has been developed and validated with the experimental data. The pre-exponential factor and activation energy for the alumina hydrolysis, Al-water reaction, and diffusion in the product layer are estimated based on the proposed model. The effects of growing particle size, formation and breakage of initial porous boehmite (AlOOH) layer, multi-stage reaction kinetics on the overall reaction rate are incorporated in the model. The study results show that the overall reaction rate is jointly controlled by simultaneous action of individual driving force, including mass transfer, chemical reaction and diffusion. The improved model enables the predictions of induction period and the evolution rate of hydrogen as a function of time, temperature and particle size. [Display omitted] • Hydroxide products formed from Aluminum powders hydration were characterized. • An improved multi-stage shrinking core model for Al–H 2 O reaction was proposed. • The kinetic parameters were estimated by a series of isothermal experiments. • Reactivity of the Aluminum powders depends on temperature and particle size. [ABSTRACT FROM AUTHOR]

• Chitosan-graft-poly (N-vinyl pyrrolidone) was developed as a dual-function inhibitor. • DFHI can inhibit the formation, reformation, and decomposition of methane hydrates. • DFHI can weaken the memory effect of hydrate reformation. In the process of drilling and producing natural gas hydrates, the hydrate is prone to decomposition, leading to wellbore instability and well control problems, and the natural gas produced by the decomposition is prone to form hydrate again in the low-temperature and high-pressure wellbore, creating flow obstacles. The existing inhibitors, however, fail to effectively inhibit the decomposition and reformation of hydrates. In this work, N-vinylpyrrolidone was used to modify chitosan, and an inhibitor namely DFHI with a dual function of inhibiting hydrate decomposition and reformation was developed. The inhibitory effects of DFHI were analyzed using the optimized experimental method for evaluating hydrate decomposition and reformation, and the mechanism was analyzed. The results showed that the memory effect of hydrate reformation gradually weakened or even disappeared with the rising ambient temperature during hydrate decomposition. The inhibitory performance of DFHI exhibited a positive correlation with its concentration. 0.5% DFHI resulted in a 74.7% delay in the decomposition time of methane hydrate, along with an extension of the induction time for both hydrate formation and reformation by 137.2% and 262.1%, respectively, significantly weakening the memory effect of hydrate reformation. The mechanism of DFHI inhibiting hydrate decomposition primarily involves surface adsorption on hydrates and thickening effects that retard mass and heat transfer processes. During the process of hydrate formation and reformation, DFHI molecules tend to aggregate at the surface of methane bubbles, hindering gas–water contact and diffusion, particularly when numerous micro-nano bubbles generated by hydrate dissolution are present; furthermore, the adsorption of DFHI molecules on the surface of hydrates delays their nucleation and growth. [ABSTRACT FROM AUTHOR]

Clathrate hydrate has been studied for a few decades as a potential alternative energy source and gas storage medium. The direct engineering application of hydrate is still struggling due to the slow formation rate and the ambiguity of induction time. To understand the effect of nanoparticles on the hydrate nucleation induction time, we used different amounts and magnitude sizes of nano-SiO 2 particles as promoter to observe the Tetrahydrofuran (THF) hydrate induction time under repeated experiments. We conducted a statistical analysis method based on Kolmogorov-Smirnov (K–S) test and probability-probability plot (P–P plot) test for the analysis of induction time. The results showed that the logarithmic normal distribution can be used to describe the distribution of THF hydrate induction time with addition of nano-SiO 2 under repeated experiments. The expected value and variance of induction time vary with particle sizes of different magnitudes at different mass concentrations, showing different effects of nano-SiO 2 on hydrate formation and dispersion of induction time. There is a critical condition (with different sizes or mass concentrations) for the influence of nano-SiO 2 particles on the THF hydrate induction time, which determines the promoting or inhibiting effect of nano-SiO 2 particles on THF hydrate formation. • Logarithmic normal distribution was used to describe the THF hydrate induction time. • Particles with different amounts and sizes affect the hydrate formation in different ways. • There is critical condition for promoting or inhibiting effect of SiO 2 particles on hydrate. [ABSTRACT FROM AUTHOR]

• Cu-Al LDH nanofluid is synthesized using co-precipitation technique. • Cu-Al LDH nanofluid is used as a promoter for THF hydrate formation. • The formation of THF hydrate is enhanced due to the addition of LDH nanofluid. • The scatter in the induction time reduces in the presence of LDH nanofluid. • The energy consumption for THF hydrate formation reduces due to LDH nanofluid. The present study investigates the effectiveness of Copper-Aluminium layered double hydroxide (Cu-Al LDH) nanofluid as a promoter for reduction of induction time and enhancement of THF hydrate growth rate. The nanofluid (Cu-Al LDH) is prepared using the co-precipitation technique. The shape/size, surface morphology, functional group, thermal property, and suspension stability of LDH nanoparticles/nanofluid are characterized using TEM, SEM, FTIR spectroscopy, thermal conductivity, and zeta potential measurement, respectively. THF hydrate experiments are performed at atmospheric pressure and stoichiometric concentration (19.06 wt%). The effectiveness of LDH nanofluid is tested at four concentrations (0.25, 0.5, 1.0, and 2.0 wt%) and reactor temperatures (1.0, 2.0, 2.5, and 3.0 °C). The shortest induction time, highest hydrate growth rate, and lowest energy consumption occur at 1.0 wt% concentration of LDH nanofluid and 1.0 °C reactor temperature. The THF hydrate nucleation is a stochastic process, and the presence of LDH nanofluid reduces the scatter in induction time. Induction time decreases from 152.8 min (for pure THF hydrate case) to 44.4 min, i.e., by 71 % in the presence of 1.0 wt% LDH nanofluid concentration at 2 °C reactor temperature. [ABSTRACT FROM AUTHOR]

• The nucleation behavior of tiamulin hydrogen fumarate methanol solvate (THFMS) was investigated. • The solubility and cosolvency effect of THFMS were studied in methanol-ethyl acetate binary mixtures. • The interfacial energy, the critical nucleation potential, and the critical nucleation parameterswere discussed. To investigate the nucleation behavior of tiamulin hydrogen fumarate methanol solvate (THFMS), the solubility, induction time, and metastable zone width (MSZW) of THFMS in methanol-ethyl acetate binary mixtures were measured. The nucleation potential model, which is based on the classical nucleation theory and correlates the induction time and MSZW, has been employed to deal with the experimental data and estimate the interfacial energy and the critical nucleation potential. The estimated values determined from the nucleation potential model are in accordance with the experimental values. The interfacial energy and the critical nucleation potential of THFMS steadily decrease with the increasing saturation temperature, whereas those of THFMS initially decrease and subsequently increase as the ethyl acetate content increases. The results demonstrate that an increase in saturation temperature leads to enhanced nucleation favorability, while the difficulty of nucleation initially decreases and then increases with increasing ethyl acetate content. Furthermore, the critical nucleation parameters, including the critical Gibbs free energy, the critical nucleus size, and the critical number of molecules in a nucleus, exhibit the same trend in alterations regarding both saturation temperature and ethyl acetate content. [ABSTRACT FROM AUTHOR]

• The concomitant polymorphism phenomenon of risperidone in ethyl acetate was investigated. • The nucleation tendencies of form I and form II were analyzed from thermodynamic and kinetic perspectives. • The reasons behind the concomitant polymorphism phenomenon was elucidated based on nucleation parameters of form I and form II. • The occurrence of concomitant polymorphism during slow-cooling crystallization process was discussed. Concomitant polymorphism is a widespread occurrence in industrial crystallization processes. A thorough understanding of this phenomenon is essential to prevent the emergence of undesirable polymorphs and ensure the production of high-quality products. In this study, the induction time method was employed to investigate the concomitant polymorphism phenomenon of risperidone in ethyl acetate. The impact of crystallization temperature and stirring rate on the concomitant polymorphism region was explored. Additionally, an analysis of the nucleation tendencies of risperidone form I and form II was conducted from both thermodynamic and kinetic perspectives. Based on the induction time theory, the nucleation parameters of form I and form II were calculated. Through an examination of the change in these nucleation parameters with supersaturation, a comprehensive explanation was provided for the reasons behind the occurrence of concomitant polymorphism and the nucleation behavior of form I and form II under varying degrees of supersaturation. Moreover, the concomitant polymorphism phenomenon during the slow-cooling crystallization process was investigated, and the relationship between operational conditions and the concomitant polymorphism region was discussed. [ABSTRACT FROM AUTHOR]

Gas hydrates have been considered promising in gas storage, gas separation, and water desalination. The hydrates' technical application is affected by the long kinetics time. Of interest is gas hydrates show strong facilitation in dissociated water containing a high concentration of micro-nanobubbles. Here, it was discovered that the nano-particles present in the dissociated water were identified as nano-bubbles, characterized by nanoparticle track analyzer and infrared spectrum. The presence of bubbles increased the nucleation probability, likely attributed to the provision of nucleation sites. Results indicated that the ability of facilitation was related to the nanobubble types: the bubble solution with the same guest molecules exhibited similar facilitation to dissociated water; specifically, the average induction time was shortened by 27.48 %, the nucleation probability was increased by 50 % compared to deionized water. Moreover, the time hydrate filled the field of view with high bubble concentration was reduced by 60 % compared with low bubble concentration. The facilitation effect mechanism could be related to the presence of gas-dense regions inside the bubbles, based on the Raman results. This finding may offer valuable insights for the application of hydrate-based energy storage technology and shed light on the potential role of bubbles in causing memory effects. • Nano-bubbles are generated as a result of gas hydrate dissociation. • These bubbles have the potential to facilitate hydrate nucleation, with the specific bubble type influencing the process. • The bubbles play a role in promoting hydrate growth, reducing the growth time by 60 %. • The existence of high-pressure zones within the bubbles may be confirmed. [ABSTRACT FROM AUTHOR]

• The nucleation behavior and nucleation kinetics of cinnamic acid were investigated and calculated. • Both the solute–solute and solute–solvent interactions during nucleation process were explored by molecular simulation. • The intrinsic mechanism of different solvents affecting the desolvation process was revealed. In this paper, the induction time and the metastable zone widths (MSZWs) of cinnamic acid in four pure solvents methanol, ethanol, acetone, and ethyl acetate were determined. Driven by the same supersaturation, the induction time is ethyl acetate > methanol > ethanol > acetone in descending order, then the effect of solvent on nucleation was further investigated by model fitting and molecular dynamic (MD) simulation. The MSZWs were fitted with the Nývlt's approach and Modified Sangwal's theory to investigate its nucleation kinetics. The results show that the fitted interfacial energy γ increases with decreasing saturation temperature and increasing cooling rate, which explains why nucleation is more likely to occur at high saturation temperatures and low cooling rates. Also, the pre-exponential factor A exhibits a strong correlation with the solvent and cooling rate. Further calculations of the key nucleation parameters (r crit , Δ G crit , J) show a positive relationship between the critical nucleation radius r crit and the critical Gibbs free energy Δ G crit. The nucleation rate J is equilibrated under the combined constraints of saturation temperature and driving force Δ µ. Finally, the intermolecular forces in the lattice were analyzed using Hirshfeld surface (HS) and 2D fingerprinting to probe the self-assembly process of molecules. And the hydrogen bonding sites between solute and solvent were predicted by molecular electrostatic potential surface (MEPs). The solute–solvent interaction was visualized by radial distribution function (RDF) and then quantified by calculating the interaction energy. The results show that the stronger hydrogen bonding interactions lead to lower nucleation rates, revealing the important role of solute–solute and solute–solvent interactions in solute desolvation and nucleation process. [ABSTRACT FROM AUTHOR]

[Display omitted] It has been shown that in the carbon dioxide–water system, the rate of gas hydrate nucleation increases with decreasing pH of the aqueous phase. Thus, a new approach has been demonstrated to control the rate of nucleation of carbon dioxide hydrate. Of interest is the question of the prospects for extending this approach to control the nucleation of other hydrates. [ABSTRACT FROM AUTHOR]

In highly concentrated solutions, with complex ionic composition, the nuclei formation and their surface deposition/growth might result in a severe membrane scaling risk and limit their efficiency. Some scaling prevention techniques exist which are based on correction in feedwater composition and/or antiscalant addition, affecting either ionic equilibriums or sparingly soluble salts formation (nucleation, crystal growth, and deposition). Contrary, a different approach seems to be rational. It includes specific physical aspects of the scaling-underlying phenomena. The idea is based on the identification of the scaling-free operating conditions by adjusting the time required for the ions to pass through RO module with nucleation induction times (metastability) of the potential scalants. Stable performance of the membrane module may be possible without any antiscalants addition. Analysis of membrane modules, of different residence time distributions (effect of spacers geometry and flow rate), was done. The authors' own experimental data concerning the maximal attainable supersaturation Cmax of CaSO4 for different dC/dt and NaCl concentrations (CNaCl), were coupled with literature data of induction time tind in these systems. As a result simulation of membrane safe work scenarios with the identification of the operational limits was possible. Some economically optimal exploitation strategies and practical design rules were suggested. [ABSTRACT FROM AUTHOR]

Ammonium alum is an important powder material for producing high purity alumina. It is usually obtained by crystallization from aqueous solution, but impurity ions in solution have a great effect on the quality of final product particles. Effects of sodium, potassium and iron ions on the primary nucleation of ammonium alum were studied by measuring induction time and metastable zone width using focused beam reflectance measurement (FBRM). It was found that potassium ion or iron ion enhanced the nucleation, whereas sodium ion had no obvious effect. Analysis about the mechanism of impurity incorporation showed that, due to the isomorphous substitution, potassium ion or iron ion were easily incorporated into ammonium alum crystals. Moreover, potassium ion was more easily incorporated into crystal than iron ion. Unlabelled Image • Potassium and iron ions promote the nucleation of ammonium alum. • Sodium ion has no significant influence on the nucleation. • Isomorphous substitution leads to the incorporation of potassium and iron ions into crystals. • Potassium ion is more easily built into the crystal than iron ion [ABSTRACT FROM AUTHOR]

The attachment interaction in a flotation process is critical because it controls the recovery of mineral particles and is dominated by the interaction energy barrier between bubbles and solid particles. In this investigation, the surface properties of coal particles and oily bubbles were evaluated via the X-ray photoelectron spectroscopy (XPS) analysis, zeta potential measurement and induction time tests. The results proved that the classical Derjagin–Landau–Verwey–Overbeek (DLVO) theory did not adequately predict the flotation performances of oily bubble flotation. The attractive interaction or hydrophobic force induced by the hydrophobic force should be considered in the extended DLVO (EDLVO) theory. Throughout this paper, therefore, it is significant to consider the attractive interaction or hydrophobic force between low-rank coal particles and oily bubbles when comparing the advantages of the flotation response using air and oily bubbles. Unlabelled Image • Both DLVO and extended DLVO theory were applied to calculate the energy barrier of oily bubble-coal particle interaction. • Long-flame coal concentrate with 83.33% yield was obtained from oily bubble flotation. • Hydrophobic force is the primary driving force for oily bubble–particle adhesion. [ABSTRACT FROM AUTHOR]

The effect of ozone and hydrogen peroxide as dopants on hydrogen-air and ethylene-air detonations was investigated with one-dimensional ZND calculations. Also, the effects of dopants were studied numerically with argon and helium as diluents with an aim to reduce the temperature of detonation products while maintaining a detonation wave of sufficient strength such that its propagation is stable near its propagation limits. The primary goal of the present investigation is to isolate the chemical kinetic effects from fluid and gas dynamic effects by altering the ignition chemistry of an unburned mixture without significantly changing its thermodynamic and physical properties. The ZND calculations demonstrate that the addition of O 3 and H 2 O 2 in small quantities will substantially reduce the induction length (Δ i) and time (τ i), even with higher diluent percentages of argon and helium, making it a viable solution for reducing the operating temperatures of rotating detonation engines (RDEs). The effects of O 3 and H 2 O 2 are also studied numerically at lower equivalence ratios for H 2 /C 2 H 4 -air detonations with an aim to reduce the post-detonation temperatures below 2000 K for its application in practical engine cycles. Also, the efficacy of CF 3 I, as an ignition promoter at small quantities, is studied numerically for hydrogen-air detonations, and its performance is compared with O 3 and H 2 O 2. [ABSTRACT FROM AUTHOR]

The use of anaesthetics to lower stress in fish farming activities and other routine operations is common in aquaculture. Sodium bicarbonate, also known as baking soda/powder is a recognised and accepted anaesthetic substance commonly used in aquaculture. However, this is not the case in some developing countries such as Zambia, thus limiting the fish farmers' options of using cheaper locally available chemicals as anaesthetic agents in fish culture. Our study aimed at assessing the anaesthetic effects of sodium bicarbonate on greenhead tilapia broodstock. A total of 90 Oreochromis macrochir broodstock (weight 160 ± 10 g and length 169 ± 10 mm) were exposed in triplicates to a sodium bicarbonate bath solution at concentrations of 0.0, 5.0, 10.0, 15.0, 20.0 and 30.0 g/L; and fish per transparent plastic tank (20 L) were used. Induction and recovery time were monitored using a stopwatch. The results of this study revealed a significant effect (P < 0.001) of sodium bicarbonate on both the induction and recovery time for O. macrochir broodstock. Survival rate was 100% and fish resumed normal swimming and feeding soon after the experiment. We therefore recommend sodium bicarbonate to be used as an anaesthetic owing to its availability and affordability. [ABSTRACT FROM AUTHOR]

• Sucralose shows potential as a green kinetic promoter for gas hydrates. • Sucralose enhances gas uptake: 37% increase at 0.75 wt% in CO 2 hydrate formation. • Sucralose increases the growth rate of carbon dioxide hydrate formation. • Sucralose increases the water to hydrate conversion and storage capacity. Gas hydrates represent a cutting-edge technology for the separation and storage of greenhouse gases, capturing the interest of numerous researchers. Nevertheless, the challenges of low storage capacity and slow hydrate formation can be surmounted through the application of kinetic promoters. This study investigates the kinetic parameters of CO 2 hydrate formation with the influence of sucralose, an eco-friendly additive, at various concentrations. Lab-scale experiments were conducted in a reactor, with initial conditions of 3 MPa pressure and 274.15 K temperature. Among the tested concentrations, the addition of 0.75 wt% sucralose exhibited the highest gas consumption and storage capacity. Compared to pure water at t = 300 min, the inclusion of 0.75 wt% sucralose resulted in a 37 % increase in gas consumption and a corresponding enhancement in storage capacity. Likewise, at t = 20 min, the water-to-hydrate conversion and storage capacity (SC) increased by approximately 35 % compared to pure water. However, as the sucralose concentration in the aqueous solution surpassed 0.75 wt%, the promoting effect on gas consumption declined, showing a diminishing return. Notably, a slight inhibitory behavior was observed during the experiment with a 10 wt% sucralose concentration. Furthermore, the experiments were replicated for certain sucralose concentrations in the aqueous solution under the same initial pressure but at an elevated temperature of 276.15 K. The results demonstrated a reduction in the promoting effect of sucralose, suggesting that raising the cell temperature during the hydrate formation process negatively impacted the kinetic parameters. [ABSTRACT FROM AUTHOR]

[Display omitted] • Isothermal calorimetry allowed rapid and non-invasive screening of mayonnaise. • Typical workflow was used to transform the heat flow data to oxygen consumption. • Simultaneous determination of antioxidant efficiency, capacity and oxidizability. • Extra virgin olive oil mayonnaise showed highest oxidative stability. This study aimed to introduce a new method based on isothermal calorimetry (IC) for measuring the autoxidation rate in mayonnaise samples. Mayonnaise samples were prepared by homogenizing an aqueous phase, consisting of vinegar and egg yolk, with various oil phases, including sunflower, corn, extra virgin olive, grape seed, and apple seed oils at 60 °C. The rate of free radical formation (R i) was controlled by adding AIBN (R i = 4.4±0.1×10−9 M/s). The autoxidation rate determined by IC was highly correlated with the one measured using the oxygen uptake method (R2 = 0.99). The IC method accurately indicated the antioxidant capacity and rates of both inhibited and uninhibited periods, together with the oxidizability of mayonnaise samples. The mayonnaise made with extra virgin olive oil exhibited the lowest oxidizability, while sunflower oil showed maximum antioxidant efficiency. A significant advantage of the IC method was its ability to simultaneously measure up to 24 samples with minimal effort. [ABSTRACT FROM AUTHOR]

It has been understood through many studies that particle shape is important in terms of particle adhesion to air bubbles in flotation. However, there are many questions yet to be answered. Whether the surface of the particle or its sharp corners is effective is only one of the issues that need to be better understood. Therefore, this study aims to delve deeper into the fundamental studies on the role of particle's geometry (surface, edges, and vertex) in their flotation behavior by investigating the attachment of spherical, cylindrical, triangular prismatic, and cubic particles to air bubbles based on their attachment efficiency, settling velocity, collision efficiency, and induction time. Bubble-particle attachment test results inferred that the attachment efficiency was in the order of cubic > triangular > cylindrical > spherical. In addition, it was found that the induction time of the spherical surface decreased from 37 ms to 15 ms with increasing collector concentration, while the induction time of the edged cubic particle decreased from 8 ms to 2 ms. This was attributed to the fact that the edge facilitates the drainage, thinning, and rupture of the water film between the bubble and the particle, thereby increasing the attachment efficiency. Finally, it has also been observed that the three-phase contact line of the cube particle is larger than that of the spherical particle, which improves the attachment stability and reduces detachment efficiency. The results obtained in this study shed light on the fact that the shape of the particles fed to flotation can be produced by using a suitable mill and thus higher flotation efficiency can be achieved with lower collector concentration. [Display omitted] • Effect of cubic, triangular prismatic, cylindrical, and spherical particles on the attachment behavior were investigated. • The order of the attachment efficiency is: cubic > triangular prismatic > cylindrical > spherical. • Settling orientation and velocity vitally affect bubble-particle attachment. • Edges and vertexes produced higher attachment efficiency than surfaces. [ABSTRACT FROM AUTHOR]

• Solid concentration was a determinant for comparing wet and dry grinding kinetics. • Both abrasion and disintegrative fracture behaviors made particles rounded. • Differences in shape and roughness between dry and wet grinding were evaluated. • Particles with irregular shape and smooth surfaces presented shorter induction times. This study explored the influence of wet and dry grinding conditions on breakage rate, shape factor and surface roughness of ground particles, induction time (the threshold for particle–bubble attachment to occur), and flotation recovery. The experimental results indicated that the dry grinding breakage rate was much higher than the wet grinding one. The first-order region was limited to a relatively short grinding time, where it was considered that little or no secondary breakage occurred. With the increasing time, the dry grinding breakage rate increased, while it decreased for wet grinding (solid concentration of 70 vol.%). The differences in shape factor and surface roughness of the wet- and dry-ground samples were attributed to different breakage mechanisms and grinding energy amounts generated by those two types of procedures. The wet-ground particles were characterized by more irregular shape factors and smoother surfaces, and thus presented shorter induction times and higher floatation recoveries compared to the dry-ground ones. [ABSTRACT FROM AUTHOR]

Formation of gas hydrates is a first-order phase transition that starts with nucleation. Nucleation rate is central to nucleation phenomena of any system as it defines the rate at which critical nuclei form in a unit volume or other measures of system size. For gas hydrates, a primary difficulty in the investigation of gas hydrate nucleation has been the inability of researchers to compare nucleation rates of gas hydrates across various systems of different scales and complexity, as it is not even clear which measure(s) of system size is most appropriate to use in a given circumstance. This inadequacy in turn has been limiting the capacity of researchers to investigate the nucleation process itself. Here we first derived general scaling laws of nucleation rates of gas hydrate systems and then applied it to compare the nucleation rate of methane hydrate determined by a High Pressure Automated Lag Time Apparatus (HP-ALTA) to that of a flow loop. The ratio of the nucleation rates of two systems (of the same guest gas and at the same driving force) scales linearly with the ratio of the system sizes (i.e., the ratio of most probable induction times scales linearly with the inverse of the ratio of the system sizes). Comparison of five conceivable measures of the system size for the scaling suggests that the total length of the three-phase-lines in the system is the most appropriate measure for scaling of the nucleation rate of methane hydrate. [ABSTRACT FROM AUTHOR]

• SDS, CTAB and water-based nanofluids of SiO 2 , Al 2 O 3 , and CuO are used as kinetic promoters in hydrate formation process. • Englezos - Bishnoi model is utilized for calculating the apparent rate constant of hydrate growth. • SDS and CTAB are the most effective promoters in increasing the average apparent rate constant and water to hydrate conversion. • SiO 2 nanofluid shows the most promising promotion effects by reducing the induction times of CO 2 and CH 4 hydrates formation. • SDS Aqueous solution is the most effective promoter that can enhance the average apparent rate constant of CO 2 and CH 4. Sodium dodecyl sulfate (SDS) with concentrations of 300 ppm and 500 ppm; cetyl trimethylammonium bromide (CTAB) with concentrations of 220 ppm and 700 ppm; and water-based nanofluids of SiO 2 , Al 2 O 3 , and CuO with concentrations of 0.1, 0.3, and 0.5 wt% were used as kinetic promoters in methane hydrate formation process at initial conditions of 274.15 K and 5.5 MPa and carbon dioxide hydrate formation process at initial conditions of 274.15 K and 3 MPa. Englezos and Bishnoi model was utilized for calculating the apparent rate constant of hydrate growth and van der Waals-platteeuw model coupled with CPA equation of state was used to model hydrate phase equilibrium conditions. SDS with a concentration of 500 ppm and CTAB with a concentration of 700 ppm are the most effective promoters in increasing the average apparent rate constant and water to hydrate conversion. SiO 2 nanofluid with a concentration of 0.3 wt% shows the most promising promotion effects by reducing the induction times of CO 2 and CH 4 hydrates formation by 70 and 74%, respectively. Aqueous solution of SDS with a concentration of 500 ppm is the most effective promoter that can enhance the average apparent rate constant of CO 2 and CH 4 by 350 and 200%, respectively. [ABSTRACT FROM AUTHOR]

Al-water reaction promoted by catalysts is a promising hydrogen generation technology. In this work, a high-activity M-B/γ-Al 2 O 3 (M = Co, Ni) catalyst is prepared by wet chemical reduction method. It is found that M-B/γ-Al 2 O 3 catalyst significantly promotes the Al-water reaction and decreases the induction time. When the molar ratio of γ-Al 2 O 3 to Co-M in Co–B/γ-Al 2 O 3 catalyst is 1:1, the induction time is only 0.43 h. The catalytic activity of M-B/γ-Al 2 O 3 is proportional to its active area. SEM analyses show that M-B particles are dispersed on γ-Al 2 O 3 surface, which reduces the agglomeration of M-B and increases the active surface of M-B/γ-Al 2 O 3 , leading to a high catalytic activity. A possible mechanism is proposed, which shows that the dissociation of water molecules on γ-Al 2 O 3 surface and the microgalvanic interaction between M-B and Al can promote the hydration process of passive oxide film on Al particle surface, speeding up the Al-water reaction. Image 1 • High-activity M-B/γ-Al 2 O 3 catalyst was prepared by wet chemical reduction method. • M-B/γ-Al 2 O 3 greatly promotes the Al-water reaction and decreases the induction time. • The catalytic activity of M-B/γ-Al 2 O 3 is proportional to its active area. • A possible mechanism for Al-water reaction promoted by M-B/γ-Al 2 O 3 was proposed. [ABSTRACT FROM AUTHOR]

An improved, high pressure, stirred automated lag time apparatus (HPS-ALTA) was used to determine gas hydrate nucleation and growth rates from induction time measurements at fixed subcooling. The improved HPS-ALTA uses multiple thermoelectric elements to allow rapid, radially symmetric heating and cooling, which together with the automatic detection of hydrate formation, makes feasible the measurement of statistically significant induction time distributions. Four induction time probability distributions, with between 83 and 312 points, were measured at subcoolings ranging from (6 to 9.7) K for water with a synthetic natural gas mixture at pressures around 12 MPa. The induction time data measured at each subcooling were exponentially distributed and were fit using a model derived from Classical Nucleation Theory based on the mononuclear nucleation mechanism. The nucleation rates obtained in this work were consistent within a factor of three or better with recent literature measurements made using a completely different apparatus. Hydrate growth rates measured at fixed subcooling using the improved HPS-ALTA were also found to be stochastic but consistent with previous measurements of the kinetic growth rate in a binary gas mixture. The results obtained here establish the need to improve theoretical models of hydrate formation to reconcile predicted nucleation rates with the much slower ones observed experimentally. [ABSTRACT FROM AUTHOR]

Gas hydrate technology is a promising approach for carbon capture. However, due to the multi-physics and multi-scale complexity of the process, this technology is not sufficiently understood for real-life scale applications. In particular, further fundamental studies of the hydrate formation mechanisms and rate are needed to achieve relevant insights into the process design and intensification. High-fidelity numerical models are crucial to capture and explain the dominant physicochemical mechanisms involved in the process. This paper presents a new variation of the shrinking core model (SCM) that can capture the practically observed features of the carbon dioxide (CO 2) hydration process, including the nucleation phase behavior and induction time, which have not been exploited previously. Accordingly, the most significant contribution of the current work to the literature is the proposal and demonstration of an efficient and rapid predictive tool for the CO 2 hydrate nucleation process. Moreover, a model-based estimation of the induction time, as a critical parameter in CO 2 hydrate rate estimation and control, is presented. Additionally, the temperature history profile over the nucleation and growth phases is simulated and compared against experimental data from the literature. The proposed model offers an in-depth and rationale analysis tool compared to the primary forms of the SCM and other models in which the nucleation stage has been compromised for the sake of mathematical modeling and numerical solution simplicity. The proposed concept is generic enough to be used for CH 4 hydration process too. Image 10481 • A kinetic model is presented to observe features of the hydrate-based CO 2 capture. • The model is able to predict the nucleation phase behavior and induction time. • Temperature history profile over the nucleation and growth phases is simulated. • The numerical estimation of the internal concentration profiles for a hydrating particle is demonstrated. • A model-based criterion was proposed to estimate the nucleation number. [ABSTRACT FROM AUTHOR]

• Initial coating preferentially formed on defects and scratches, and around bubbles on the surface. • Induction time was influenced by initial deposition, and not just by local composition, as demonstrated experimentally. • Coating deposition was favored for areas with a high local current density. The purpose of this study was to develop a detailed understanding of the initial stages of coating electrodeposition. Of particular interest were the changes that take place during the induction period before a steep change in the voltage at constant current is observed. Experiments designed to elucidate the role of concentration buildup clearly showed that a local change in concentration was not solely responsible for the observed induction period. This conclusion is further supported by experiments where the induction time at a specified current was observed to vary with the type of substrate used for deposition. Consequently, scanning electron microscopy was used to study the morphology of the initial deposit on different substrate surfaces including bare steel, galvanized steel, and phosphated steel. It was found that the initial film formed preferentially at specific locations on the metal surfaces, such as on defects or scratches, where the local current density was likely to be higher. The initial film also appeared to form around gas bubbles that were present on the substrate surface. Preferential film deposition at areas of high local current density was observed directly in experiments with intentionally scratched surfaces. The additional insight provided by this study will help to improve our ability to model accurately the early stages of E-coat deposition and, eventually, the accuracy of large-scale simulations for process performance prediction and optimization. [ABSTRACT FROM AUTHOR]

Abstract Natural gas + water-in-diesel emulsion + AA systems with and without wax were used to investigate the influence of wax crystals and their heat- and mass-transfer effect on hydrate formation from macroscopic and microscopic aspect in a flow system. Hydrate nucleation and initial growth were found to be a partially occurred phenomenon. Wax was found to prolong the hydrate induction time through two significant effects: one was the macroscopic heat-transfer effect produced by wax deposition with insulating effect, and the other was the microscopic mass-transfer resistance originating from the wax crystals that were adsorbed at or adjacent to the oil-water interface. Hydrate induction time shortened and became less scattered with the increasing initial pressure. Based on the heat-transfer theory of a flow system and the hydrate nucleation theory, an improved model for hydrate induction time prediction was developed by coupling calculation of hydraulics and heat-transfer and by introducing mass-transfer effect of adsorption of wax crystals. The findings of this work are meaningful for providing essential information and supports for the ongoing deep-sea oil and gas production and the application of hydrate-management strategies in the presence of wax crystals in a flow system. [ABSTRACT FROM AUTHOR]

Abstract This study was aimed at the synthesis of pure phase zeolite 4A from coal fly ash sourced from Nishat power plant in the Punjab province of Pakistan. Analysis of fly ash (FA) demonstrated that it can be used to produce low silicate type zeolites specifically zeolite 4A due to its Si/Al molar ratio of ∼2. The current investigation emphasized on the addition of induction time (before and after crystallization) to the fly ash extract of Si-Al-Na species that was extracted from fly ash. The induction time helped in catalysing primary and secondary gel formation during the synthesis leading to controlled formation of single phase with high crystallinity and small crystallite size. The physiochemical investigations of synthetic zeolite 4A by using various analytical techniques made the proposed process justified on comparison with commercial zeolite 4A. The X-Ray Diffraction (XRD) analysis for synthesize zeolite 4A confirmed only one crystallographic phase and small crystallite size with 82% crystallinity compared to reference zeolite with 75% crystallinity. Fourier-Transform Infrared spectroscopy (FTIR) spectra revealed the structural aspects of synthesis and reference zeolite by indicating the presence of identical structural units with same height and width of peaks. Morphological analysis by Scanning Electron Microscope (SEM) showed a well-defined cubic shape of synthesis zeolitic crystals. Surface area analyses by Brunauer–Emmett–Teller (BET) showed that synthesized zeolite possessed 122 m2/g surface area that is 3 times higher than reference zeolite of 36.3 m2/g. The synthesized zeolite was also found to have smaller particle size than reference zeolite. Thermal stability comparison of both zeolites was studied by non-isothermal Thermo Gravimetric Analysis-Differential Thermal Analysis (TGA-DTA) thermograms from 25 to 800 °C temperature and both the samples were found to be stable at 800 °C. Highlights • Pakistani Coal Fly ash for synthesis of zeolite 4A and waste into useful material. • New step of induction time in the conventional two-step hydrothermal synthesis. • Pure, single-phase crystals with high crystallinity and small crystallite size. • Comparative physiochemical analysis of the synthesized and reference zeolite 4A. • Analytical techniques employed were XRD, SEM, BET, FTIR, PSA, EDX and TGA. [ABSTRACT FROM AUTHOR]

In this work, the impact of functional group on the thermodynamics and kinetics of CO 2 hydrates are investigated experimentally. The hydroxylated multi-wall carbon nanotubes (OH-MWCNT) and carboxylated carbon nanotubes (COOH-MWCNT) along with pristine carbon nanotubes (MWCNT) are selected for this study. The carbon nanotubes are suspended in a 0.03 wt% sodium dodecyl sulfate (SDS) aqueous solution and the results are compared with SDS aqueous solution at the same concentration of 0.03 wt% and deionized water. The CO 2 hydrate phase boundary and kinetic parameters of CO 2 hydrate formation including induction time, the initial rate and amount of gas consumed, gas uptake, storage capacity, and water to hydrates conversion are studied. The results show that the nanofluids studied do not affect the equilibrium conditions of CO 2 hydrates. In addition, 0.01 and 0.05 wt% of COOH-MWCNT mixed with 0.03 wt% SDS showed highest initial hydrate formation rate and gas uptake. Furthermore, a comparison between SDS and COOH-MWCNT (without stabilizer SDS) at 0.03 wt% revealed that addition of COOH-MWCNT to the water enhance the initial hydrates formation rate compared to SDS. • Carbon nanotube does not change CO 2 phase equilibrium. • The kinetic of CO 2 hydrates formation in the presence of SDS and carbon nanotube are discussed. • Nanofluid contain 0.05 wt% COOH-MWCNT+0.03 wt% SDS is the most efficient promoter. • Surfactant-free of COOH-MWCNT nanofluid show higher initial CO 2 hydrate formation rate compared to SDS. • Amount of gas consumption, storage capacity, and water to hydrates conversion rate are discussed. [ABSTRACT FROM AUTHOR]

In hospitals, operating rooms (ORs) are very demanding in terms of the indoor air quality (IAQ) and require systems that minimize the concentrations of pollutants (microorganisms, chemical and particulate matter). Air treatment devices that use photocatalytic oxidation (PCO) could potentially be used in the OR to improve IAQ. In this work, the fate of two OR pollutants acrylonitrile (chemical found in surgical smoke) and isoflurane (anesthetic gas) when they go through a PCO device was investigated. The experiments were conducted in a laboratory closed loop multi-pass reactor. A mathematical model was utilized to enable the calculation of one indicator (single-pass removal efficiency) for acrylonitrile and two indicators (induction period and single-pass removal efficiency) for isoflurane. The degradation efficiency was then accessed by studying the influence of environmental parameters on these indicators. The parameters that were studied are the relative humidity, presence of co-pollutants and presence of particles. The parameters were observed to have similar effects on the degradation of both compounds. Increasing relative humidity inhibited the degradation probably due to competitive adsorption. The presence of co-pollutants like nitrous oxide and acetic acid caused a possible competition for adsorption unto active sites thus decreased the degradation efficiency of acrylonitrile and isoflurane. The increase in the concentration of the co-pollutants enhances the competitive effect and further decreases the degradation efficiency of the target pollutants. Finally the presence of particles on the photocatalytic media could block active sites thereby inhibiting the degradation of acrylonitrile and isoflurane. Image 1 • The influence of relative humidity, co-pollutants and particles on PCO of isoflurane and acrylonitrile is studied for first time. • RH inhibits the degradation of compounds probably due to competitive adsorption between water and pollutant molecules. • The presence of co-pollutants decreases the removal efficiency of the target pollutants probably due to competitive adsorption. • The presence of particles on media may block the active sites and thus decrease the removal of acrylonitrile and isoflurane. [ABSTRACT FROM AUTHOR]

Abstract Flotation strongly depends on bubble–particle attachment interactions. However, modelling of bubble–particle attachment interactions is challenging particularly due to the difficulties in quantifying the hydrophobic interactions between an air bubble and a non-spherical particle using a well-advanced technique such as atomic force microscopy; the reason is that these measurements are not reproducible when particles are non-spherical. This paper proposes a methodology to determine the hydrophobic interaction constants between air bubbles and coal particles in the presence of a surfactant. The bubble–particle hydrophobic constants were determined from first principles using the Navier-Stokes equation and the Glembotsky experimental technique. It was found that the higher the surfactant concentration, the higher the hydrophobic constants. The results showed that the calculated critical film rupture thickness is inversely related to the induction time measurements, and the maximum critical film rupture thickness matched the minimum induction time. The decrease in the electrostatic double layer repulsive energies resulted in the decrease in the induction times. Highlights • Thin liquid film drainage mechanism was studied. • The hydrophobic constants between bubbles and coal particles were determined. • The induction time is inversely related with the critical film thickness. • The electrostatic force affected more film rupture than the hydrophobic forces. [ABSTRACT FROM AUTHOR]

Abstract Particle-bubble interactions play a vital role in froth flotation that is widely used for the recovery of valuable minerals from gangue minerals. In this study the effects of nanobubbles on particle-bubble interactions were visualized using a specially designed apparatus to show the trajectory of solid particles of different degrees of hydrophobicity moving around a regular sized flotation bubble. It has been shown that particle hydrophobicity and the nanobubbles generated on particle surface enhance the particle-bubble interaction process by affecting the balance between the hydrodynamic and surface chemistry forces that control the trajectory of a particle moving around a bubble surface. Increased particle surface hydrophobicity in terms of contact angle from 50o to 85o and 110o enhanced the particle-bubble interaction by reducing the induction time from 75 ms to 52 ms and 48 ms, respectively. In the presence of nanobubbles on particle surface, the thin film between the particle and the bubble ruptures up to 50% faster. It has also been observed that nanobubbles are capable of producing fine particle aggregates that facilitate the particle-bubble interaction process. Graphical abstract Nanobubble Effects on Hydrodynamic Interactions between Particles and Bubbles Unlabelled Image Highlights • A specially designed apparatus developed for visualizing particle-bubble interactions • Shorter induction time visualized with increased particle hydrophobicity. • Faster attachment observed in presence of nanobubbles on particle surfaces. • Fine particle aggregates enhanced collision and attachment probabilities. • Larger detachment monitored with increased particles size. [ABSTRACT FROM AUTHOR]

Highlights • Bubble–particle attachments were studied in a flotation cell. • The flotation recoveries were highly sensitive to the changes in pulp chemical conditions. • The induction times were marginally sensitive to the changes in pulp chemical conditions. • Attachment efficiency vs induction time decreased exponentially. Abstract The controlling step for successful flotation is a bubble–particle attachment mechanism. Induction times cannot be measured directly in flotation cells due to the presence of a large number of bubbles and particles. Thus, the possibility is to determine induction times using fundamental flotation models. The focus of this technical note is to determine the induction times in a flotation column under different chemical environments and thus evaluate whether the induction times can be used to predict the flotation recoveries. In this work, the sized pyrite particles (−212 + 150 μm, −150 + 75 μm and −75 + 38 μm) were used during the flotation tests. The fundamental flotation model was used to back-calculate the induction times from the flotation experimental data. It was found that the induction times and the flotation rate constants could be used to quantify the flotation performances. However, for the same particle size fraction, the flotation recovery was very sensitive to the changes in the pulp chemical conditions while the flotation rates and particularly the induction times slightly changed. The attachment efficiency-induction time curve was significantly less sensitive to identify the changes in particle sizes than the flotation rate-induction time curves. [ABSTRACT FROM AUTHOR]

Abstract The flotation performance of lignite is poor even if a high dosage of the collector is used. In this work, the lignite in the Huolinhe Coalfield of Inner Mongolia was used, and its physicochemical properties were determined by proximate analysis, particle size analysis and Fourier transform infrared spectroscopy. The flotation performances of lignite using six collectors were investigated. Moreover, the flotation responses of lignite with combined collector and two emulsified collectors were compared. It was found that the polar groups in the collector structure were helpful to improve the flotation of lignite through reducing the induction time to 15 ms, only 1/12 of that of the traditional collector (190 ms for diesel). The induction time was in the order of diesel> kerosene> emulsified kerosene> emulsified diesel> C1 (one of the nameless collectors), consistent with the flotation performance. C1 and emulsified collectors significantly improved the flotation performance of lignite by promoting the floating of coarse coal (−500 + 250 μm). Graphical abstract Unlabelled Image Highlights • The surface of the lignite is rich in polar functional groups. • A large amount of collector is saved using emulsified collectors. • The emulsified collector improves the recovery of coarse particles and reduces the induction time. [ABSTRACT FROM AUTHOR]

Abstract Induction time and agglomeration of methane hydrate formation in dispersed systems play an important role in exploitation of natural gas hydrate, prevention of gas hydrate plug, and application of hydrate-based technologies. In this work, an autoclave with particle video microscope (PVM) probe was used to detect induction time of methane hydrate formation as a function of the water cut, dosage of sorbitan monolaurate (Span 20), and subcooling. Forty-one experiments and thirty-six experiments of induction time have been conducted for methane hydrate formation at constant pressure and at nonconstant pressure, respectively. The results showed subcooling was the major factor that affects induction time during methane hydrate formation process. Subcooling of 4 K can be seen as an inflection point because the average methane hydrate formation time was less than 200 min when the subcooling was greater than 4 K, while methane hydrate formation time exhibited more stochastic when the subcooling was less than 4 K. The results also suggested that there exists a transformation range of subcooling (TRS) during methane hydrate formation process. The agglomerated mechanism of methane gas hydrate may be changed when the subcooling is greater than TRS, and subcooling of 4 K is included in the TRS. Highlights • Seventy-seven induction time data for methane hydrate formation were obtained. • Subcooling of 4 K was the inflection point for control of induction time. • Agglomeration of methane hydrate at low subcooling was more complex. • Transformation range of subcooling may exist when methane hydrate formed. [ABSTRACT FROM AUTHOR]

Highlights • The induction time of coal fly ash of −125 + 74 μm was 15 ms. • The contact angle significant increased after conditioning by diesel oil. • The size fraction of −125 + 74 μm had lowest wetting heat of −2.55 J/g. • Six flotation kinetic models were fitted to the flotation of coal fly ash. Abstract The effect of particle size on the flotation behavior of coal fly ash was investigated in this study. Three narrow particle size fractions, −125 + 74 μm, −74 + 45 μm, and −45 μm, and the unclassified particle size fraction of −500 μm of coal fly ash were chosen to study the basic properties by the measurement of induction time, contact angle, and wetting heat. Furthermore, flotation kinetic tests of coal fly ash with different particle size fractions were conducted. The results show that particle size significantly affects the flotation kinetics of coal fly ash, and the intermediate particle size fractions of −125 + 74 μm and −74 + 45 μm had better flotation performance and higher flotation rate than the fine particle size of −45 μm. Six flotation kinetic models were used to fit the test data of the cumulative unburned carbon recovery in the coal fly ash flotation. The parameters of flotation rate (k), maximum unburned carbon recovery (ε ∞), and correlation coefficient (R2) were analyzed in detail. The fitted results from the data showed that, for each size fraction, the froth flotation of coal fly ash can be best described by the classical first-order model. [ABSTRACT FROM AUTHOR]

Abstract The presence of clay minerals presents a great challenge to fine coal and mineral flotation due to the well-known phenomena of mechanical coating and water entrainment. In this paper, we study the effect of two different types of clay, kaolinite and montmorillonite, on the floatability of coal in de-ionized water (without flotation reagents) based on induction time and bubble-particle attachment kinetics. The bubble-particle attachment angle (BPAA) as a function of time was used as the kinetics raw data. We demonstrated how the presence of montmorillonite was detrimental to the floatability of coal in de-ionized water. This was not the case with kaolinite. The induction time and BPAA kinetics of coal particles only changed slightly after conditioning together with kaolinite. In contrast, the induction time increased considerably from 8.73 ms to 83.25 ms when montmorillonite was added. In addition, both the maximum BPAA and BPAA kinetics constant decreased, and hydrophilic montmorillonite coating occurred during the conditioning stage. These hydrophilic sites on the coal surface prevent the thinning-rupture of the water film between bubble and coal particles and thus decrease the floatability and recovery. Graphical abstract Unlabelled Image Highlights • Role of different types of clay in coal floatability was studied. • Kaolinite had little effect on coal floatability. • Montmorillonite was detrimental to coal floatability. • Hydrophilic montmorillonite coating occurred in DI water. [ABSTRACT FROM AUTHOR]