Bulk Kinetics Research Articles

Parallel and High Throughput Reaction Monitoring with Computer Vision

AbstractWe report the development and applications of a computer vision based reaction monitoring method for parallel and high throughput experimentation (HTE). Whereas previous efforts reported methods to extract bulk kinetics of one reaction from one video, this new approach enables one video to capture bulk kinetics of multiple reactions running in parallel. Case studies, in and beyond well‐plate high throughput settings, are described. Analysis of parallel dye‐quenching hydroxylations, DMAP‐catalysed esterification, solid‐liquid sedimentation dynamics, metal catalyst degradation, and biologically‐relevant sugar‐mediated nitro reduction reactions have each provided insight into the scope and limitations of camera‐enabled high throughput kinetics as a means of widening known analytical bottlenecks in HTE for reaction discovery, mechanistic understanding, and optimisation. It is envisaged that the nature of the multi‐reaction time‐resolved datasets made available by this analytical approach will later serve a broad range of downstream efforts in machine learning approaches to exploring chemical space.

Enhancing the photoelectrochemical performance of TiO2 photoanode by employing carbon nanoparticles as electron reservoirs and photothermal materials.

Photoelectrochemical (PEC) water splitting is regarded as a potential technique for converting solar energy. However, the fast charge recombination and slow water oxidation kinetics significantly have hindered its practical application. It is found that an elevation in operation temperature can activate the charge transport in the photoanodes. Here, a strategy was performed that carbon nanoparticles were employed to TiO2 nanorods, acting as electron reservoirs as well as photothermal materials. More specifically, a record photocurrent density of 1.62mAcm-2 at 1.23V vs. RHE has been achieved, accompanied by a high charge separation efficiency of 96% and a long-term durability for 8h. The detailed experimental results reveal that under NIR light irradiation, the synergistic effect between electron storage and temperature rise leads to accelerated charge transport in the bulk and water oxidation kinetics on the surface. This research offers a new perspective on how to boost the PEC performance of photoelectrodes.

Parallel and High Throughput Reaction Monitoring with Computer Vision.

We report the development and applications of a computer vision based reaction monitoring method for parallel and high throughput experimentation (HTE). Whereas previous efforts reported methods to extract bulk kinetics of one reaction from one video, this new approach enables one video to capture bulk kinetics of multiple reactions running in parallel. Case studies, in and beyond well-plate high throughput settings, are described. Analysis of parallel dye-quenching hydroxylations, DMAP-catalysed esterification, solid-liquid sedimentation dynamics, metal catalyst degradation, and biologically-relevant sugar-mediated nitro reduction reactions have each provided insight into the scope and limitations of camera-enabled high throughput kinetics as a means of widening known analytical bottlenecks in HTE for reaction discovery, mechanistic understanding, and optimisation. It is envisaged that the nature of the multi-reaction time-resolved datasets made available by this analytical approach will later serve a broad range of downstream efforts in machine learning approaches to exploring chemical space.

Modeling the mechanosensitive collective migration of cells on the surface and the interior of morphing soft tissues.

Cellular contractility, migration, and extracellular matrix (ECM) mechanics are critical for a wide range of biological processes including embryonic development, wound healing, tissue morphogenesis, and regeneration. Even though the distinct response of cells near the tissue periphery has been previously observed in cell-laden microtissues, including faster kinetics and more prominent cell-ECM interactions, there are currently no models that can fully combine coupled surface and bulk mechanics and kinetics to recapitulate the morphogenic response of these constructs. Mailand et al. (Biophys J 117(5):975-986, 2019) had shown the importance of active elastocapillarity in cell-laden microtissues, but modeling the distinct mechanosensitive migration of cells on the periphery and the interior of highly deforming tissues has not been possible thus far, especially in the presence of active elastocapillary effects. This paper presents a framework for understanding the interplay between cellular contractility, migration, and ECM mechanics in dynamically morphing soft tissues accounting for distinct cellular responses in the bulk and the surface of tissues. The major novelty of this approach is that it enables modeling the distinct migratory and contractile response of cells residing on the tissue surface and the bulk, where concurrently the morphing soft tissues undergo large deformations driven by cell contractility. Additionally, the simulation results capture the changes in shape and cell concentration for wounded and intact microtissues, enabling the interpretation of experimental data. The numerical procedure that accounts for mechanosensitive stress generation, large deformations, diffusive migration in the bulk and a distinct mechanism for diffusive migration on deforming surfaces is inspired from recent work on bulk and surface poroelasticity of hydrogels involving elastocapillary effects, but in this work, a two-field weak form is proposed and is able to alleviate numerical instabilities that were observed in the original method that utilized a three-field mixed finite element formulation.

Topological Defect-Regulated Porous Carbon Anodes with Fast Interfacial and Bulk Kinetics for High-Rate and High-Energy-Density Potassium-Ion Batteries.

Carbonaceous materials are regarded as one of the most promising anodes for potassium-ion batteries (PIBs), but their rate capabilities are largely limited by the slow solid-state potassium diffusion kinetics inside anode and sluggish interfacial potassium ion transfer process. Herein, high-rate and high-capacity PIBs are demonstrated by facile topological defect-regulation of the microstructure of carbon anodes. The carbon lattice of the as-obtained porous carbon nanosheets (CNSs) with abundant topological defects (TDPCNSs) holds relatively highpotassium adsorption energy yet low potassium migration barrier, thereby enabling efficient storage and diffusion of potassium inside graphitic layers. Moreover, the topological defects can induce preferential decomposition of anions, leading to the formation of high potassium ion conductive solid electrolyte interphase (SEI) film with decreased potassium ion de-solvation and transfer barrier. Additionally, the dominant sp2-hybridized carbon conjugated skeleton of TDPCNSs enables high electrical conductivity (39.4 S cm-1) and relatively low potassium storage potential. As a result, the as-constructed TDPCNSs anode demonstrates high potassium storage capacity (504mA h g-1 at 0.1 A g-1), remarkable rate capability (118mA h g-1 at 40 A g-1), as well as long-term cycling stability.

Investigating the Impact of Na2WO4 Doping in La2O3-Catalyzed OCM Reaction: A Structure–Activity Study via In Situ XRD-MS

The La2O3 catalyst exhibits good performance in OCM reactions for its promising C2 selectivity and yield. Previous studies have affirmed that the formation of carbonates in La2O3 impedes the catalyst’s activity as a result of poisoning from CO2 exposure. In this study, a series of Na2WO4-impregnated La2O3 catalysts were synthesized to investigate the poisoning-resistant effect. The bulk phase and kinetics of the catalysts were analyzed in reactors employed with in situ XRD-MS and online MS, focusing on the CO2 adsorption on La2O3 and the phase transition process to La2O2CO3 in temperature zone correlated to OCM light-off. In situ XRD analysis revealed that, with Na2WO4 doped, CO2 exposure at elevated temperatures formed La2O2CO3 in tetragonal crystal phases, exhibiting distinctive differences from the hexagonal phase carbonates in undoped commercial La2O3. The ability to develop tetragonal or monoclinic La2O2CO3 was suggested as a descriptor to assess the sensitivity of La2O3 catalysts to CO2 adsorption, a tunable characteristic found in this study through varying Na2WO4 doping levels. Coupled XRD-MS analysis of CO2 adsorption uptake and phase change further confirmed a positive dependence between the resistivity of La2O3 catalyst to CO2 adsorption and its low-temperature C2 selectivity. The results extended the previous CO2 poisoning effect from multiple perspectives, offering a novel modification approach for enhancing the low-temperature performance of La2O3 catalysts in OCM.

Colloidal Ternary Telluride Quantum Dots for Tunable Phase Change Optics in the Visible and Near-Infrared.

A structural change between amorphous and crystalline phase provides a basis for reliable and modular photonic and electronic devices, such as nonvolatile memory, beam steerers, solid-state reflective displays, or mid-IR antennas. In this paper, we leverage the benefits of liquid-based synthesis to access phase-change memory tellurides in the form of colloidally stable quantum dots. We report a library of ternary MxGe1-xTe colloids (where M is Sn, Bi, Pb, In, Co, Ag) and then showcase the phase, composition, and size tunability for Sn-Ge-Te quantum dots. Full chemical control of Sn-Ge-Te quantum dots permits a systematic study of structural and optical properties of this phase-change nanomaterial. Specifically, we report composition-dependent crystallization temperature for Sn-Ge-Te quantum dots, which is notably higher compared to bulk thin films. This gives the synergistic benefit of tailoring dopant and material dimension to combine the superior aging properties and ultrafast crystallization kinetics of bulk Sn-Ge-Te, while improving memory data retention due to nanoscale size effects. Furthermore, we discover a large reflectivity contrast between amorphous and crystalline Sn-Ge-Te thin films, exceeding 0.7 in the near-IR spectrum region. We utilize these excellent phase-change optical properties of Sn-Ge-Te quantum dots along with liquid-based processability for nonvolatile multicolor images and electro-optical phase-change devices. Our colloidal approach for phase-change applications offers higher customizability of materials, simpler fabrication, and further miniaturization to the sub-10 nm phase-change devices.

Kinetics Study of Acid-Catalyzed Sulfate Esterification Reactions for Atmospherically Relevant Polyols

Extensive laboratory and field studies have identified organosulfates as important constituents of secondary organic aerosol (SOA). However, the mechanisms by which these organosulfates form in the atmosphere remain uncertain. The rate constants for the acid-catalyzed sulfate esterification reactions of a series of polyols were measured via bulk kinetics experiments using nuclear magnetic resonance (NMR) spectroscopy. The NMR data indicated that while reactions that occurred at a terminal hydroxyl site were somewhat faster than reactions at internal hydroxyl sites, there were no other significant structure–reactivity trends among the series of polyols. These results suggest that neighboring hydroxyl groups do not significantly modify the sulfate esterification rates from those previously determined for monoalcohols. Extrapolation of the kinetics data to typical atmospheric SOA acidities suggests that sulfate esterification reactions of polyols are unlikely to be a significant source of organosulfates. This conclusion is consistent with a previous study of monoalcohols which made similar conclusions about the kinetic infeasibility of this reaction type.

Geochemical, mineralogical and petrographical characteristics of the domanik formation from north samara region in the volga-ural basin, Russia: Implication for unconventional tight oil reservoir potential

This paper comprehensively analyzes the geochemical, mineralogical and petrographical properties combined with bulk kinetics modeling of the Domanik organic-rich carbonate from various depth intervals in Kuzminovsky oilfield (well № 26 R), Volga-Ural Basin, Russia. The results show that, the Domanik carbonate-rich samples are characterized by high content of the total organic matter (TOC) up to 13.31 wt %, and contain mainly Type II kerogen with a slight II/III kerogen type, reaching very good to excellent oil generation potential. Moreover, the studied samples contain hydrogen-rich kerogen, which expected to generate paraffin, naphthene and aromatic (P–N-A) oil with low wax content as demonstrated by the Py-GC Pyrolysis combined with the abundance of fluorescent alginite, amorphous organic matter, and bituminite as established from investigations via microscope. The maturity indicators demonstrated that, most of the examined Domanik carbonate-rich samples, with a burial depth between 1726.5 m and 1784.9 m, have generally reached low thermal maturity stages; thus, defining an immature to moderate-mature of oil generation window. The results of the kinetic models suggested that, Domanik carbonate-rich rocks with vitrinite reflectance (VRo) values in the range of 0.60–0.71%, have reached relatively low kerogen transformation ratio in the range of 10–20%, indicating low probability oil generation. These finding are confirmed by the presence of low oil saturation index of less than 100 mg HC/g rock (19.64–69.97). In addition, the results of thin section, scanning electron microscopy (SEM) and micro-computed tomography (micro-CT) showed that the studied samples are characterized by low porosity (up to 3.29%) with a wide pores size range, including interparticle, cavities, cracks and organic matter pores. The development of these pore types and their quality in the studied samples is mainly controlled by high mineralogical brittleness (i.e., carbonate and quartz) together with the high organic matter inputs. Therefore, according to the obtained results, characteristics and observations, the Domanik Formation has a high potential for commercial oil production, which typically requires hydraulic fracturing followed by an in-situ retort, mainly by thermal methods such as steam injection and in situ combustion process.

Hydraulic fracturing as unconventional production potential for the organic-rich carbonate reservoir rocks in the Abu El Gharadig Field, north western Desert (Egypt): Evidence from combined organic geochemical, petrophysical and bulk kinetics modeling results

This paper systematically analyzes the organic geochemical, petrophysical, and petrographical properties combined with bulk kinetics modeling of the Abu Roash (F) organic-rich carbonate rocks in the Abu El Gharadig Field. The Abu Roash (F) carbonate-rich samples exhibit high organic content with total organic matter (TOC) values up to 3.04 wt%, and mainly Type II kerogen, with a slight gradient to Type II/III and III kerogens, reaching good to very good oil generation potential. This finding of hydrogen-rich kerogen and oil generation potential was also demonstrated by the abundance of fluorescent alginite, amorphous organic matter (AOM), and bituminite organic matter (OM) as established via ultra violet (UV) light microscopy. The maturity indicators demonstrate that most of the examined Abu Roash (F) carbonate-rich samples from the studied wells, with a deep burial depth of more than 3000 m, are thermally mature, thus defining an early mature to moderate-mature stage. The kinetic models suggest that the Abu Roash (F) carbonate-rich rocks in the deepest burial depth, with calculated vitrinite reflectance (%VRo) values in the range of 0.72–0.83 %, have reached kerogen transformation ratio (TR) in the range of 10–55 %, indicating a high probability of oil production. This finding is confirmed by the presence of the oil crossover in these rocks with an oil saturation index (OSI) of more than 100 mg HC/ g rock. The Abu Roash (F) organic-rich carbonates are intractable rocks as implied by low porosities (up to 2.33 %) and poor permeability in the range of 0.0017–0.0039 mD. The pores in these rocks have a wide range in size, including interparticle, fracture, and organic matter (OM) pores, as recognized in the thin section and scanning electron microscopy (SEM). The development of these pore types and their quality is mainly controlled by high mineralogical brittleness (i.e., carbonates) together with the high OM inputs. Based on the above characteristics, the Abu Roash (F) carbonate-rich rocks in the Abu El Gharadig Field are a candidate for unconventional tight oil reservoir potential, which typically require a form of hydraulic fracturing for possible oil production at deeper burial depths.

Development and Comparison of Water Quality Network Model and Data Analytics Model for Monochloramine Decay Prediction

The conventional drinking water treatment process involves disinfecting water at the final stage of treatment to ensure water is microbiologically safe at customer taps. Monochloramine is a popular disinfectant used in many water distribution systems (WDSs) worldwide. Understanding the factors that impact monochloramine decay in the WDS is critical for maintaining disinfection at the customer tap. While monochloramine residue moves through a WDS, it decays via several pathways including chemical, microbiological, and wall decay processes. The decay profile in these pathways is often site-specific and depends on various factors including treated water characteristics. In a water quality network model, the decay of a chemical species is often modelled using two parameters that represent bulk and wall decay kinetics. Typical bulk decay characteristics of monochloramine for a specific WDS can be easily established in the laboratory using grab sample tests, while in a real situation, wall decay is difficult to quantify. In this study, we compared two different approaches to model monochloramine decay in a WDS. In the first approach, the wall decay parameter was quantified using a parameter optimisation technique with monochloramine concentrations at different network locations simulated using a water quality network model. In the second approach, a data analytics model was developed using a machine learning algorithm. For both approaches, the model predicted monochloramine concentrations closely matched the observed data. Our study suggests that the data analytics model has a relatively higher accuracy in predicting monochloramine residual concentrations in a WDS.

Occurrence of Mid Jurassic, organic-rich, lacustrine deposits on the southern Utsira High

A detailed biostratigraphic and organic geochemical investigation was undertaken of an organic-rich, lacustrine interval at ∼2622–2639 m in well 16/4–10, in the Fosen Prospect on the Utsira High in the Norwegian North Sea. A Bajocian to Aalenian age is suggested, similar to that for the immediately overlying Sleipner Fm, whereas the underlying strata were effectively barren and could not be dated with confidence. The dark grey claystone of the lacustrine unit is dominated by Botryococcus contributions, as indicated by palynofacies analysis. The kerogen exhibits a typical algaenan signature with a dominant single activation energy value of ∼54.5 kcal/mol for its bulk kinetics. Total organic carbon (TOC) increases from ∼2% at the base to ∼11% at the top, although the hydrogen index (HI) varies throughout (∼400–∼800‰ HC/Corg). The unit is on the verge of oil generation (Tmax ∼446 °C; estimated vitrinite reflectance 0.5–0.6%; spore colour index 5). Overall, it is similar to lacustrine intervals reported in the Møyfrid Discovery (North Sea wells 2/2-1 and 2/2–4) and Kap Stewart (Jameson Land, East Greenland). Freshwater/brackish lacustrine environment indications include a high tetracyclic polyprenoid (TPP) ratio and particularly abundant 4-methyl-24-ethylcholestanes. Specific botryococcal markers are absent, but the abundant 24-ethylcholestanes probably derive from this organism. Algal contributions increase upwards (at the expense of woody higher plants), as do 3-methylhopanes, whereas the pristane/phytane ratio (Pr/Ph) decreases (from ∼4 to 2), which may reflect increasing methanogenic/methylotophic activity. The immediately overlying Sleipner Fm has much lower TOC and HI values and a greater woody higher plant contribution, in what appears to be a proximal marine setting. Beneath the lacustrine facies is ∼10 m of dominantly sandstone, underlain by brown claystone, exhibiting the characteristics of a highly oxic marine environment, with very low TOC and HI values, but high oxygen index (OI) and Pr/Ph. The Fosen lake seems to correspond to one of numerous mini-basins in the area attributed to Zechstein salt withdrawal during the Jurassic. Like the Møyfrid lake, it appears to lie near the periphery of the sub-aerial, central North Sea volcanic dome. It is possible that organic-rich lacustrine facies developed in other, deeper mini-basins and have expelled some oil. Their subtle contributions to accumulations bearing other Jurassic charges may have been overlooked in the absence of obvious biomarker characteristics.

Rational construction of S-doped FeOOH onto Fe2O3 nanorods for enhanced water oxidation

Hematite-based photoanode (α-Fe2O3) is considered the promising candidate for photoelectrochemical (PEC) water splitting due to its relatively small optical bandgap. However, severe charge recombination in the bulk and poor surface water oxidation kinetics have limited the PEC performance of Fe2O3 photoelectrodes, which is far below the theoretical value. Herein, a new catalyst, S-doped FeOOH (S-FeOOH), has been immobilized onto the surface of the Fe2O3 nanorod (NR) array by a facile chemical bath deposition incorporated thermal sulfuration process. The grown S-FeOOH layer acts not only as an efficient catalyst layer to accelerate the water oxidation on the surface of photoelectrode but also constructs a heterojunction with the light absorption layer to facilitate the interface charge carrier separation and transfer. As expected, the modified S-FeOOH@Fe2O3 photoanode achieves a remarkable increase in PEC performance of 2.30 mA cm−2 at 1.23 V versus the reversible hydrogen electrode (VRHE) andan apparent negative shifted onset potential of 250 mV in comparison with pristine Fe2O3 (0.95 mA cm−2 at 1.23 VRHE). These results provide a simple and effective strategy to coupling oxygen evolution catalysts with photoanodes for practically high-performance PEC applications.

Upper Jurassic to Lower Cretaceous source rocks in the Norwegian Barents Sea, part II: Insights from open- and closed-system pyrolysis experiments

The petroleum generation potential of Upper Jurassic to Lower Cretaceous organic rich shales from the southwestern Barents Sea was evaluated using bulk and quantitative pyrolysis analysis. Fifteen thermally-immature samples from the Hekkingen Formation with differing organic facies, as defined by maceral composition, were subjected to total organic carbon, Rock-Eval pyrolysis, pyrolysis gas chromatography, bulk kinetics, and micro-scale sealed vessel pyrolysis analyses. The results were employed to characterize differences in source rock kerogens, gross petroleum type, and the compositional evolution of the generated fluids as well as their physical properties (i.e. gas to oil ratio, saturation pressure, and formation volume factor) as a function of increasing maturity.The investigated samples contain varying proportions of kerogen type II and III. Heterogeneities in the kerogen composition result in different orders of thermal stability, with the onset of petroleum generation predicted to occur over a high and broad temperature range from 123 °C to 144 °C (at 3.3C⁰/Ma). Reduced kerogen stability associated with elevated sulfur contents is only documented in a few samples. Most of the analyzed samples have the potential to generate low GOR oils of an intermediate to aromatic, low wax paraffinic-naphthenic-aromatic (P–N-A) composition and variable amounts of wet gas. Petroleums of similar compositional and physical properties are predicted to have been generated from the natural maturation sequence of various organic facies in thermally mature areas of the Hammerfest Basin and the Ringvassøy-Loppa High and Bjørnøyrenna fault complexes. Vitrinite-rich sources in the Fingerdjupet Sub-basin and the Troms-Finnmark Fault Complex have potential for gas and condensate generation.

Enhanced photoelectrochemical water oxidation in Hematite: Accelerated charge separation with Co doping

Hematite (α-Fe2O3) is one of the most promising candidates for a photoanode for photoelectrochemical water splitting. However, it has low efficiency because of poor conductivity in the bulk and sluggish oxygen evolution (OER) kinetics on the surface. In this study, a Co-doped α-Fe2O3 photoanode was prepared by the hydrothermal method. It had increased charge separation efficiency and accelerated surface reaction kinetics simultaneously. At the optimal Co content, the photocurrent density of the Co-doped α-Fe2O3 increased by 23 times to 0.54 mA/cm2 at 1.23 VRHE in 1 M NaOH electrolyte; this increase was attributed to the improvement in carrier density and charge transfer behavior. Moreover, the cathodic shift of onset potential for Co-doped α-Fe2O3 reached 290 mV owing to the accelerated OER kinetics. This work reveals the key roles of Co doping and provides a suitable photoanode for solar hydrogen technology.

Crystallization Fouling in Domestic Appliances and Systems

Formation of mineral scale, particularly calcium carbonate, has long been a concern in domestic appliances such as boilers, steamers and washing machines. In this work, the formation of inorganic deposits was studied on solid surfaces and in the bulk solution as a result of evaporation of potable water. Scale precipitation was evaluated on metallic samples for various bulk temperatures, surface roughness and surface material as a function of time. The morphology of scale crystals from both surface and solution was evaluated. The microstructure and morphology of deposits on the surface were analyzed using Scanning Electron Microscopy and X-ray diffraction. The present work has demonstrated that deposition rates increase as the evaporation process proceeds as expected. The nature of the material and the surface roughness both affect surface deposition kinetics. The complex relationship between the saturation ratio (as the bulk solution shows precipitation) and the kinetics of bulk and surface precipitation/deposition is demonstrated. The prevailing crystalline form of calcium carbonate is aragonite. However, the polymorphic composition of surface deposition and the bulk precipitate is influenced by temperature.

Alginite-Rich Layers in the Bazhenov Deposits of Western Siberia

In this study, we identified the luminescent layers containing a significant amount of alginite in the Upper Jurassic–Lower Cretaceous Bazhenov Formation named “the alginite-rich layers”. Lithological and geochemical methods were used to determine distinctive features of these layers and to evaluate their impact on the total petroleum generation potential of the Bazhenov Formation. We have shown that the composition of the alginite-rich layers differs significantly from the organic-rich siliceous Bazhenov rocks. Rock-Eval pyrolysis, bulk kinetics of thermal decomposition, elemental analysis, and the composition of pyrolysis products indicate type I kerogen to be the predominant component of the organic matter (OM). Isotope composition of carbon, nitrogen, and sulfur was used to provide insights into their origin and formation pathways. The luminescent alginite-rich layers proved to be good regional stratigraphic markers of the Bazhenov Formation due to widespread distribution over the central part of Western Siberia. They can also be applied for maturity evaluation of the deposits from immature to middle of the oil window, since the luminescence of the layers changes the color and intensity during maturation.

Bulk and pipe wall chlorine degradation kinetics in three water distribution systems

ABSTRACT This paper presents a methodology to estimate free residual chlorine concentrations (FRCC) in full-scale water distribution system (WDS) using different degradation kinetics according to pipe material, age and diameter. Intensive field sampling campaigns and laboratory-scale tests were carried out to estimate total and bulk volume FRCC in three WDS. Bulk kinetic constants were estimated for water temperatures typical of different seasons in the Quebec City area (Canada). With field-measured FRCC at all sampling sites and an estimation of travel times through the use of a hydraulic model, total, bulk and pipe wall kinetic constants were obtained with ranges of 10.2 to 130.4, 4.1 to 43.8 and 8.5 to 114.9 10−3/h, respectively. Pipe wall kinetics tend to dominate the total degradation process for older grey and ductile cast-iron pipes, followed by newer ductile iron pipes and then PVC and pre-stressed concrete pipes (mostly installed from 1990). The developed methodology and results will be useful to improve the prediction of FRCC through hydraulic and water quality modelling.

Theoretical and Experimental Parameters of the Structure and Crystallization Kinetics of Melt-Quenched As30Te64Ga6 Glassy Alloy

The present framework reports the structural, fundamental parameters, and crystallization kinetics of the melt-quenched As30Te64Ga6 chalcogenide glass. The energy dispersive X-ray analysis of the As30Te64Ga6 glassy system reveals that the constituent element ratio of the investigated bulk sample agrees with the nominal composition. Also, X-ray diffraction (XRD) and Differential Scanning Calorimetry (DSC) were used to characterize structural properties, and crystallization kinetics; respectively. Four characteristic temperatures related to various phenomena are observed in the investigated DSC traces. The first one is $$T_{g}$$ that corresponds to the glass transition temperature. The second one is ( $$T_{c1}$$ , and $$T_{c2}$$ ) that corresponds to the onset of the double crystallization temperatures. The third one ( $$T_{P1}$$ , and $$T_{P2}$$ ) identifies the double peak crystallization temperatures. The last characteristic temperature ( $$T_{m}$$ ) is the melting point. The XRD analysis indicates the amorphous structure of the as-prepared glassy alloy, while the annealed samples are polycrystalline. The crystallization kinetics of the As30Te64Ga6 bulk are studied under non-isothermal conditions. In addition, the values of various kinetic parameters such as the glass transition activation energy, weight stability standard, and Avrami exponent were determined. The activation energy of the crystallization process for As30Te64Ga6 glass alloy was calculated using classical methods. The results indicated that the rate of crystallization is related to thermal stability and the ability to form glass. Kinetic parameters have been estimated with some conventional methods and found to be dependent on heating rates (β).

Influence of Bulk and Surface Interactions from Thick, Porous, Soil-based Substrates on the Spreading Behavior of Different Viscosity Oils

Crude oils and motor oils are commonly identified in oil spills on land. Controlling and understanding their flow both across and into land is of paramount importance to minimize spread and subsequent damage to the ecosystem. Spreading kinetics and surface energy studies were conducted with these oils over several realistic soil-based matrixes, consisting of topsoil (silt-dominant), sand, clay, and moisture. Spreading area through a 1.3 cm deep matrix was reduced with increased moisture content, densely packed matrixes, and higher viscosity oils. Initial contact angle (CA) measurements for all oils was typically lower on clay matrixes due to its sheet-like structure and high absorption capabilities. Individual droplet penetration took longer at lower MC in direct contradiction to bulk kinetics studies, suggesting different spreading behavior across the surface border. Low viscosity oils recorded the highest lateral spreads, and incomplete wetting profiles were identified for most conditions tested. Importantly, dimensionless profiles of droplet diameter and CA with time did not conform to universal behavior, with statistically significant influences of matrix heterogeneity, oil viscosity, and ill-controlled surface roughness identified. Flow regimes of oil droplets instead conformed to vertical spreading through thick matrixes, and a delayed lateral spreading that occurred quite late into the total penetration time of the droplet. These findings, obtained from studying realistic soil-based matrixes, draws new conclusions regarding the important influences of matrix thickness, variable porosity, and chemical heterogeneity on fluid flow behavior. This new knowledge will assist in the development of future containment efforts surrounding oil spills.