Kinetic Balance Research Articles

How the Kinetic Balance Between Charge-Transfer and Mass-Transfer Influences Zinc Anode Stability: An Ultramicroelectrode Study.

Aqueous zinc-metal batteries (AZMBs) represent a promising frontier in battery technology, offering sustainable and safe alternatives to traditional non-aqueous batteries. Despite their potential, understanding the kinetics of zinc electrodeposition-a critical factor in AZMB performance-remains underexplored. Utilizing voltammetry on ultramicroelectrodes, we investigate how scan rate influences key processes of nucleation and growth during Zn2+ electrodeposition. The findings highlight the efficacy of the Butler-Volmer formulation in capturing electron-transfer kinetics, contrasting with complex electron transfer kinetic models usedfor non-aqueous battery chemistries. Weclearly demonstrate that there is a strong dependence of scan rate on the measured value of kinetic parameters (exchange current). To accurately probe the charge transfer kinetics, it is essential to apply fast scan voltammetry to decouple the influence of mass transfer, ensuring that the measured current is independent of the scan rate. Furthermore, by studying a model electrolyte additive, the intricate balance between charge transfer and mass transfer dynamics is unveiled, and this information is crucial for enhancing the stability of zinc metal anodes. These insights pave the way for developing advanced electrolyte and current collector formulations, promising enhanced cyclability and sustainability in zinc metal batteries.

A fine kinetic balance of interactions directs transcription factor hubs to genes.

Eukaryotic gene regulation relies on the binding of sequence-specific transcription factors (TFs). TFs bind chromatin transiently yet occupy their target sites by forming high-local concentration microenvironments (hubs and condensates) that increase the frequency of binding. Despite their ubiquity, such microenvironments are difficult to study in endogenous contexts due to technical limitations. Here, we use live embryo light-sheet imaging, single-molecule tracking, and genomics to overcome these limitations and investigate how hubs are localized to target genes to drive TF occupancy and transcription. By examining mutants of a hub-forming TF, Zelda, in Drosophila embryos, we find that hub formation propensity, spatial distributions, and temporal stabilities are differentially regulated by DNA binding and disordered protein domains. We show that hub localization to genomic targets is driven by a finely-tuned kinetic balance of interactions between proteins and chromatin, and hubs can be redirected to new genomic sites when this balance is perturbed.

Computational Design of an Electro-Organocatalyst for Conversion of CO2 into Long Chain Aldehydes.

Density functional theory calculations employing a hybrid implicit/explicit solvation method were used to demonstrate that an electro-organocatalyst designed in our previous work for reducing CO2 to formaldehyde could also be capable of coupling formaldehyde to form long chain aldehydes. The catalytic activity is enabled by an electron-rich vicinal enediamine (>N-C═C-N<) backbone that activates formaldehyde by reversing the polarity on the carbon atom, enabling it to act as a nucleophile in the subsequent aldol addition step. The catalyst then enables reductive dehydroxylation of the aldol addition product by facilitating outer-sphere electron transfer. The optimal pH as well as the limiting potential and formaldehyde concentration are identified and related to the kinetic balance between several rate limiting steps. Finally, the optimal conditions for coupling with the CO2 reduction cycle are discussed, demonstrating that the electro-organocatalyst is capable of efficiently converting CO2 into aldehyde products with a turnover frequency (per carbon atom) on the order of 0.1-1 s-1.

Metal–Organic Framework Fe-BTC as Heterogeneous Catalyst for Electro-Fenton Treatment of Tetracycline

This study explores the use of the iron-containing metal–organic framework (MOF), Basolite®F300, as a heterogeneous catalyst for electrochemically-driven Fenton processes. Electrochemical advanced oxidation processes (EAOPs) have shown promise on the abatement of recalcitrant organic pollutants such as pharmaceuticals. Tetracyclines (TC) are a frequently used class of antibiotics that are now polluting surface water and groundwater sources worldwide. Acknowledging the fast capability of EAOPs to treat persistent pharmaceutical pollutants, we propose an electrochemical Fenton treatment process that is catalyzed by the use of a commercially available MOF material to degrade TC. The efficiency of H2O2 generation in the IrO2/carbon felt setup is highlighted. However, electrochemical oxidation with H2O2 production (ECO-H2O2) alone is not enough to achieve complete TC removal, attributed to the formation of weak oxidant species. Incorporating Basolite®F300 in the heterogeneous electro-Fenton (HEF) process results in complete TC removal within 40 min, showcasing its efficacy. Additionally, this study explores the effect of varying MOF concentrations, indicating optimal removal rates at 100 mg L−1 due to a balance of kinetics and limitation of active sites of the catalysts. Furthermore, the impact of the applied current on TC removal is investigated, revealing a proportional relationship between current and removal rates. The analysis of energy efficiency emphasizes 50 mA as the optimal current, however, balancing removal efficiency with electrical energy consumption. This work highlights the potential of Basolite®F300 as an effective catalyst in the HEF process for pollutant abatement, providing valuable insights into optimizing electrified water treatment applications with MOF nanomaterials to treat organic pollutants.

Kinetic balance and some physical qualities and their relationship to the performance of the skill of short-range defensive moves handball in Karbala sports club players

Kinetic balance and some physical qualities and their relationship to the performance of the skill of short-range defensive moves handball in Karbala sports club players

The effect of educational units using snorkel mask on flexibility, kinetic balance, and learning the skills of floating and breathing in swimming for beginners

The effect of educational units using snorkel mask on flexibility, kinetic balance, and learning the skills of floating and breathing in swimming for beginners

The relationship of kinetic balance and static balance to some biokinematic variables in the skill of the forehand and backhand in tennis

The relationship of kinetic balance and static balance to some biokinematic variables in the skill of the forehand and backhand in tennis

Intermediate and high-temperature oxidation behavior of an equiatomic TaTiCr RCCA from 800 °C to 1400 °C

This study explores the oxidation behavior of a TaTiCr refractory complex concentrated alloy (RCCA) in the temperature regime of 800–1400 °C. The oxidation kinetics were found to be proportional with temperature. However, a mechanistic shift from linear oxidation kinetics at 800 °C and 1000 °C to sub-parabolic kinetics at 1200 °C and 1400 °C was observed. This was attributed to the establishment of continuous external scales of TiO2 and Cr2O3, with fairly continuous underlying complex oxide layers at the higher temperatures. While there were morphological differences in the oxide scales depending on exposure temperature, the oxide species were all similar, primarily consisting of an outer layer of TiO2, an intermediate layer of Cr2O3, and an inner layer of rutile-structured (Cr,Ta,Ti)O2. Internal nitridation was observed in all cases, with a severe degree of internal reaction at 1400 °C, reaching a depth of 750 μm. Overall, the best performance was observed at 1200 °C, where a favorable balance of kinetics and thermodynamics promoted the most continuous oxide layers, thereby enhancing oxidation resistance.

Reversible and irreversible photon-absorption in amorphous SiO2 revealed by deep potential

Understanding the kinetic balance between reversible and irreversible photon-absorption (IPA/RPA) in amorphous-SiO2 (a-SiO2) is crucial for mitigating optical damage and assessing the lifetime of irradiated optics. Experimental work has placed some thermodynamic bounds on the formation of defects from damage precursor, but the formation kinetics and underlying microscopic mechanisms are yet to be elucidated. Here, by employing deep neural network potential, we find that the formation of defects are temperature-dependent and density-dependent, where competitions between IPA and RPA take place. The IPA prevails in the early formation of E’-center, and the ratio of IPA/RPA is related to the strained bonds, SiSi bonds and 5-coordinated silicon (Si5). Furthermore, the Si5 is critical to the propagation of E’-center and densification of a-SiO2. Additionally, we develop quantitative models of defects in regard with irradiation temperature of specified temperature and irradiation photon-energy, respectively.

Unraveling Anaerobic Digestion Instability: A Simple Index Based on the Kinetic Balance of Biochemical Reactions

Restoration potential (RP) and deterioration potential (DP) were formulated to shed light on the kinetic balance between anaerobic biochemical reactions. RP is gauged by the ratio of the methanogenesis rate (MR) to the acidogenesis rate (AR), while the DP is the sum of the accumulation rate (AcR) and dilution rate (DR) of total VFAs, normalized using the AR. In an anaerobic digester for a mixture of pulverized food waste and liquified sewage sludge, an RP above 1.0 signifies a restorative state in the kinetic balance of anaerobic biochemical reactions across various operational phases, including startup and steady state, and shifts in organic loading rate. Conversely, a DP value of 0.0 or higher denotes a deterioration in the kinetic balance. The instability index (ISI), calculated as the DP to RP ratio, serves as an indicator of an anaerobic digestion state. When the standard deviation of ISI surpasses 0.2, it signifies instability in biochemical reactions; however, an average ISI below 0.05 indicates a stable digestion process. The study underscores the efficacy of RP, DP, and ISI as robust indicators for assessing the stability of anaerobic digestion based on the kinetics of biochemical reactions.

Relativistic resolution-of-the-identity with Cholesky integral decomposition.

In this study, we present an efficient integral decomposition approach called the restricted-kinetic-balance resolution-of-the-identity (RKB-RI) algorithm, which utilizes a tunable RI method based on the Cholesky integral decomposition for in-core relativistic quantum chemistry calculations. The RKB-RI algorithm incorporates the restricted-kinetic-balance condition and offers a versatile framework for accurate computations. Notably, the Cholesky integral decomposition is employed not only to approximate symmetric large-component electron repulsion integrals but also those involving small-component basis functions. In addition to comprehensive error analysis, we investigate crucial conditions, such as the kinetic balance condition and variational stability, which underlie the applicability of Dirac relativistic electronic structure theory. We compare the computational cost of the RKB-RI approach with the full in-core method to assess its efficiency. To evaluate the accuracy and reliability of the RKB-RI method proposed in this work, we employ actinyl oxides as benchmark systems, leveraging their properties for validation purposes. This investigation provides valuable insights into the capabilities and performance of the RKB-RI algorithm and establishes its potential as a powerful tool in the field of relativistic quantum chemistry.

Rücktitelbild Chem. Ing. Tech. 5/2023

Chemie Ingenieur TechnikVolume 95, Issue 5 p. 800-800 Back CoverFree Access Rücktitelbild Chem. Ing. Tech. 5/2023 First published: 25 April 2023 https://doi.org/10.1002/cite.202370508AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Graphical Abstract A Kinetic & Heat Balance Model for Anionic Polymerization. Copyright: Felix Kandelhard Anionic polymerization is an established method for the synthesis of block copolymers. Due to the high reaction rates, a good knowledge of the process and its heat generation is of great importance for safe reaction control. The developed model, validated based on the block-co-polymerizations of styrene and isoprene, enables a prediction of the temperature profiles and the molecular weight distributions of the synthesized polymer. As a tool to identify the influence of various process parameters and the composition of the reaction mixture on the polymerization, it can be very useful in the optimization of anionic batch polymerizations. F. Kandelhard, P. Georgopanos, Chem. Ing. Tech. 2023, 95 (5), 754-760. DOI: 10.1002/cite.202200205 Volume95, Issue5Special Issue: Reaktionstechnik und Wärme‐ und StoffaustauschMay 2023Pages 800-800 RelatedInformation

A Kinetic and Heat Balance Model for Anionic Batch Block Copolymerization of Styrene and Isoprene

AbstractAnionic polymerization is an established process for the synthesis of well‐defined block copolymers. Due to the high reaction rates, a good knowledge of the process and its heat generation is of great importance for safe reaction control. This is to be achieved by the development and validation of a combined kinetic and heat transport model. The validation of the combined model was based on the experimentally anionic homo‐polymerization of styrene that was expanded for the block co‐polymerization of styrene and isoprene carried out in cyclohexane in batch reactors.

Revealing the Kinetic Balance between Proton-Feeding and Hydrogenation in CO2 Electroreduction.

Electrocatalytic reduction of CO2 to high-value-added chemicals provides a feasible path for global carbon balance. Herein, the fabrication of NiNP x @NiSA y -NG (x,y= 1, 2, 3; NG = nitrogen-doped graphite) is reported, in which Ni single atom sites (NiSA ) and Ni nanoparticles (NiNP ) coexist. These NiNP x @NiSA y -NG presented a volcano-like trend for maximum CO Faradaic efficiency (FECO ) with the highest point at NiNP2 @NiSA2 -NG in CO2 RR. NiNP2 @NiSA2 -NG exhibited ≈98% of maximum FECO and a large current density of -264 mA cm-2 at -0.98 V (vs. RHE) in the flow cell. In situ experiment and density functional theory (DFT) calculations confirmed that the proper content of NiSA and NiNP balanced kinetic between proton-feeding and CO2 hydrogenation. The NiNP in NiNP2 @NiSA2 -NG promoted the formation of H* and reduced the energy barrier of *CO2 hydrogenation to *COOH, and CO desorption can be efficiently facilitated by NiSA sites, thereby resulting in enhanced CO2 RR performance.

Electrostatic-induced green and precise growth of model catalysts

Crystallographic control of crystals as catalysts with precise geometrical and chemical features is significantly important to develop sustainable chemistry, yet highly challenging. Encouraged by first principles calculations, precise structure control of ionic crystals could be realized by introducing an interfacial electrostatic field. Herein, we report an efficient insitu dipole-sourced electrostatic field modulation strategy using polarized ferroelectret, for crystal facet engineering toward challenging catalysis reactions, which avoids undesired faradic reactions or insufficient field strength by conventional external electric field. Resultantly, a distinct structure evolution from tetrahedron to polyhedron with different dominated facets of Ag3PO4 model catalyst was obtained by tuning the polarization level, and similar oriented growth was also realized by ZnO system. Theoretical calculations and simulation reveal that the generated electrostatic field can effectively guide the migration and anchoring of Ag+ precursors and free Ag3PO4 nuclei, achieving oriented crystal growth by thermodynamic and kinetic balance. The faceted Ag3PO4 catalyst exhibits high performance in photocatalytic water oxidation and nitrogen fixation for valuable chemicals production, validating the effectiveness and potential of this crystal regulation strategy. Such an electrically tunable growth concept by electrostatic field provides new synthetic insights and great opportunity to effectively tailor the crystal structures for facet-dependent catalysis.

Fate and removal of iodinated X-ray contrast media in membrane bioreactor: Microbial dynamics and effects of different operational parameters

Iodinated X-ray contrast media (ICM) are mainly used in medical sector, and their presence in environmental waters is a cause of concern as they are capable of forming highly toxic iodinated disinfection byproducts. In the present study, the removal mechanisms of the three ICM- iohexol, iopromide, and iopamidol were elucidated in a lab-scale aerobic membrane bioreactor (MBR). At steady-state operation (solids retention time (SRT)- 70 days, organic loading rate (OLR)- 0.80 KgCOD/m3-day, nitrogen loading rate (NLR)- 0.08 KgNH4-N/m3-day, hydraulic retention time (HRT)- 12 h), the average removal of iohexol and iopromide was found to be 34.9 and 45.2 %, respectively, whereas iopamidol proved to be highly recalcitrant in aerobic conditions of the MBR (removal <10 % in all phases of the MBR operation). Further, through batch kinetic studies and mass balance analysis, it was observed that ICM were primarily biotransformed in the MBR system and biosorption (Kd < 10 L/Kg) was negligible. The biodegradation rate coefficient values (Kbiol) of the ICM were found to be <0.65 L/g-d which indicate that biotransformation rate of ICM was slow. Increased OLR (1.60 KgCOD/m3-day) and reduced SRT (20 days) were found to negatively affect the removal of the ICM. Further, the removal of ICM was found to depend on its initial concentration, and the increment in the ammonium loading (0.16 KgNH4-N/m3-day) did not favor its removal. The dosing of ICM altered the microbial dynamics of the mixed liquor and reduced the microbial diversity and richness. Bdellovibrio, Zoogloea, and bacteria belonging to TM7-3 class, Cryomorphaceae and Hyphomonadaceae families may contribute in ICM biotransformation.

Influence of Redox Couple on the Performance of ZnO Dye Solar Cells and Minimodules with Benzothiadiazole-Based Photosensitizers.

ZnO-based dye-sensitized solar cells exhibit lower efficiencies than TiO2-based systems despite advantageous charge transport dynamics and versatility in terms of synthesis methods, which can be primarily ascribed to compatibility issues of ZnO with the dyes and the redox couples originally optimized for TiO2. We evaluate the performance of solar cells based on ZnO nanomaterial prepared by microwave-assisted solvothermal synthesis, using three fully organic benzothiadiazole-based dyes YKP-88, YKP-137, and MG-207, and alternative electrolyte solutions with the I-/I3 -, Co(bpy)3 2+/3+, and Cu(dmp)2 1+/2+ redox couples. The best cell performance is achieved for the dye-redox couple combination YKP-88 and Co(bpy)3 2+/3+, reaching an average efficiency of 4.7% and 5.0% for the best cell, compared to 3.7% and 3.9% for the I-/I3 - couple with the same dye. Electrical impedance spectroscopy highlights the influence of dye and redox couple chemistry on the balance of recombination and regeneration kinetics. Combined with the effects of the interaction of the redox couple with the ZnO surface, these aspects are shown to determine the solar cell performance. Minimodules based on the best systems in both parallel and series configurations reach 1.5% efficiency for an area of 23.8 cm2.

Differential effects of ibuprofen and indomethacin on cerebral oxygen kinetics in the very preterm baby.

BackgroundIbuprofen is preferred to indomethacin for treatment of a significant patent ductus arteriosus (PDA) in preterm babies despite indomethacin being associated with a lower risk of intraventricular haemorrhage. This difference is thought to relate to the discrepant effects of each medication on cerebral oxygen kinetics yet the effect of ibuprofen on cerebral perfusion is uncertain.MethodsForty-eight babies < 30 weeks with a significant PDA, defined by echocardiography, were randomly assigned to either indomethacin or ibuprofen (n = 24 per group) and stratified by gestation and chronologic age. Cerebral blood flow [total internal carotid blood flow (TICF)] and oxygen physiology [oxygen delivery (modCerbDO2) and consumption (modCerbVO2)] were measured using cranial Doppler ultrasound and near-infrared spectroscopy, and cerebral oxygen extraction (cFTOE) calculated, immediately before and following administration. Temporal and treatment related changes were analysed.ResultsA fixed effect of time was seen for TICF (p = 0.03) and therefore modCerbDO2 (p = 0.046) and cFTOE (p = 0.04) for indomethacin alone. In the indomethacin group, TICF and modCerbDO2 fell from baseline to 5 and 30 min respectively (TICF p < 0.01, cDO2 p = 0.01) before increasing from 5 min to 24 h (p < 0.01) and 30 min and 24 h (p < 0.01) timepoints. cFTOE peaked at 30 min (p = 0.02) returning to baseline at 24 h. There was a parallel increase in arterial lactate.ConclusionIndomethacin significantly reduces cerebral blood flow soon after administration, resulting in a parallel increase in oxygen extraction and arterial lactate. This implies that the balance of oxygen kinetics at the time of treatment may be critical in very preterm babies with significant PDA.

Impregnation of activated alumina with CeO2 for water defluoridation

The fluoride ion is commonly found in groundwater used for water supply and poses health risks when ingested in excess. Several treatments are studied for water defluoridation, with adsorption being one of the most used techniques. Activated alumina is an adsorbent that already has a potential for defluoridation, and can also be subjected to treatments such as impregnation of cations in order to improve its performance. Cerium is a rare earth that has affinity with fluoride. Thus, in this work, an activated alumina adsorbent impregnated with CeO2 was prepared and the defluoridation capacity in synthetic samples and groundwater samples was evaluated. To prepare the material, 10, 15, and 20% mass ratios and calcination temperature were tested. A response surface methodology was applied to determine the best conditions of fluoride removal for synthetic waters and groundwater samples, in addition to kinetic and isothermal tests. The characterization of activated alumina and activated alumina impregnated with cerium oxide was carried out in order to analyze changes in the material. The characterization of the material showed changes in the pore size, specific surface area, and pore volume, in addition to a good distribution of cerium oxide on the alumina surface. The adsorbent that showed the highest adsorption was prepared at a mass ratio of 20% cerium nitrate III and calcined at 350 °C. The best conditions of the experiment occurred at the central point, at pH 7 and dosage of adsorbent 0.3 g L−1 for synthetic sample. The isotherm that best represented the results obtained was that of Langmuir (R2 = 0.781 to 0.958), obtaining a maximum adsorption capacity (Qmax) of 6.157 mg g−1. The kinetic balance occurred in the first 10 min of contact, being best represented by the pseudo-second order model (R2 = 0.999). The results show that adsorption with activated alumina impregnated with cerium oxide is efficient for defluoridation under laboratory conditions, and further studies with groundwater are needed to assess the influence of co-existing ions.

P22. How hip are we in assessing balance strategy? Utilization of a novel force analysis technique using a single force plate to simplify assessment of adult spinal deformity patient balance strategy reliance

<h3>BACKGROUND CONTEXT</h3> Humans recruit a variety of coordination strategies to maintain upright posture while standing. These strategies arise from hip, knee and ankle torques which act in varying degrees over time to support vertical weight of the body and perturbations to balance. Prior studies suggest adult spinal deformity (ASD) surgery results in reduced postural sway and effort; however, none have directly assessed patient's strategy reliance or determined if multilevel fusion affects balance control. Recently, a novel method to assess balance strategy reliance using only a force plate called force intersection point analysis (FIP) was developed to quantify post-stroke balance deficits. The relevance of this method to spinal pathologies has yet to be determined and may provide new insight into the effects of ASD surgery on a patient's ability to maintain dynamic standing posture. <h3>PURPOSE</h3> Assess effects of spinal realignment surgery on balance strategy reliance using a novel kinetic analysis technique and to compare it with traditional full-body kinematic analysis. <h3>STUDY DESIGN/SETTING</h3> Retrospective review at a single institution. <h3>PATIENT SAMPLE</h3> Thirty-six ASD patients who underwent realignment surgery and 36 healthy (H) matched controls. <h3>OUTCOME MEASURES</h3> Patient-reported outcome measures (VAS pain for back and leg, ODI, SRS22r), radiographic outcomes (SVA, PT, PI-LL), kinematic joint ROM and kinetic balance strategy analyses. <h3>METHODS</h3> Subjects completed 60s standing tests with eyes open and arms at their sides. ASD patients were evaluated preoperatively (P0) and at 12 months (P12) after surgery. Data collection included joint range-of motion (ROM) kinematics using a motion tracking system and kinetic center of pressure (COP) using a force plate. Changes in ASD patient balance strategy were assessed using joint ROM and FIP analyses. FIP quantifies balance strategy by sway frequency: ∼1.75Hz relates to low amplitude knee and hip stabilization. FIP is reported as % of center of mass height. <h3>RESULTS</h3> ASD patients (28F/8M, 61.4±15.5yr, 1.6±0.1m, 73.5±21.6kg) were predominantly N and L curve types and had an average of 7±4 levels fused. Surgery resulted in significant improvement in alignment (Cobb: 39°@P0-19°@P12, p 0.05) at P0 and showed minimal changed at P12. FIP trends indicated a reduced reliance on higher-frequency stabilization at P12 although not significant. <h3>CONCLUSIONS</h3> FIP analysis indicated minimal changes in balance strategy reliance following ASD surgery which lends new credence to the notion that deformity correction does not worsen postural balance. Force plate FIP analysis is simple to implement and provides a direct means of quantifying balance strategy reliance. ROM analysis yielded different results and does not appear to be related to FIP behavior. Improved understanding of balance strategy may play an important role in future refinement of realignment strategies for individual ASD patients. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.