Linear Kinetics Research Articles

Population pharmacokinetic analyses for sulbactam-durlobactam using Phase 1, 2, and 3 data.

Sulbactam-durlobactam is a β-lactam/β-lactamase inhibitor combination approved in the United States for the treatment of hospital-acquired and ventilator-associated bacterial pneumonia caused by susceptible isolates of Acinetobacter baumannii-calcoaceticus in adults. A population pharmacokinetic (PK) model of sulbactam-durlobactam in plasma was developed using data from eight Phase 1-3 studies. A total of 432 subjects and 8,100 plasma concentrations were available for the population PK data set. The combined model was a four-compartment (two compartments per drug) model with linear kinetics. Both renal clearance and nonrenal clearance were estimated, and total clearance was calculated as the sum of renal and nonrenal clearance. Individual renal clearances were scaled by baseline creatinine clearance. The sampling-importance-resampling analysis indicated that the parameters were estimated reliably with adequate precision. Hemodialysis (HD) and epithelial lining fluid (ELF) sub-models were developed for each analyte separately. Intermittent HD resulted in an approximately 30% decrease in the daily area under the concentration-time curve (AUC0-24) when HD was started 1 hour after the end of the infusion. Assuming protein binding estimates of 10% and 38% for durlobactam and sulbactam, respectively, ELF penetration ratios were found to be 41.3% for durlobactam and 86.0% for sulbactam. Of the statistically significant covariates of PK identified, which included body weight, body mass index, infection type, and region of origin, renal function was the only clinically relevant covariate. Overall, a robust description of the plasma PK of sulbactam and durlobactam was achieved. The resultant population PK model was expected to be appropriate for model-based simulations and assessment of pharmacokinetic-pharmacodynamic relationships.

Levetiracetam as an Alternative to Phenytoin for Prophylactic Use in Post-Traumatic Seizures: a Literature Review

Traumatic brain injury (TBI) is a common concern for the causes of disability and mortality and it can cause post-traumatic seizure (PTS). Currently, Brain Trauma Foundation (BTF) recommends phenytoin (PHY) as early PTS prophylaxis for patients with severe TBI. The two most common drugs prescribed for PTS are levetiracetam (LEV) and PHY. However, PHY displays a wide array of disadvantages. LEV appears as a better alternative to PHY because of its easier administration, the absence of need for drug level monitoring, lower drug-drug interaction, and better side-effects profile. It is due to the linear elimination kinetics LEV had in comparison to PHY that have zero order pharmacokinetics. Theoretically, LEV is better than PHY. But according to prior studies, LEV and PHY have comparable efficacy at preventing PTS in the early stages. Furthermore, the current evidence is insufficient to definitely recommend LEV over PHY in terms of effectiveness and adverse effects. This study aimed to analyze levetiracetam as an alternative to phenytoin for prophylactic use in post-traumatic seizure.

WITHDRAWN: Studies on decontamination of cadmium rich water by a novel nano Iron oxide adsorbent

Synthesizing non-toxic adsorbent for abatement of hazardous pollutants from water is important to develop safe environment. In this study, nanocrystalline iron oxide particles were synthesized and utilized as effective nanoadsorbent for removing cadmium through adsorption. The as-prepared nanoadsorbent was characterized using sophisticated techniques. The objective of this study was to improve cadmium adsorption from aqueous solutions under a variety of conditions. With the help of Box-Behnken design, adsorption parameter settings were improved. Response Surface Methodology analysis was conducted to optimize the adsorption conditions, including pH, initial concentration of metal ions, and adsorbent dose. Comparisons were made between the optimal equations for linear and non-linear kinetics, along with isotherm models. Origin's curve fitting tool and the Solver add-in of Microsoft Excel are two non-linear analytical tools. The obtained results showed that the Origin curve fitting tool is superior to solver add in's error analysis method for determining isotherm parameters. The equilibrium data for cadmium removal using nano iron oxide/hydroxide adsorbent was best fitted to Langmuir isotherm model. The adsorption of cadmium was well described by the pseudo-second-order model. The study shows that the system appears to be spontaneous according to the Langmuir constant method and thermodynamic parameter via partition.

Modeling catalyst effectiveness factor with space-fractional derivative using Haar wavelet collocation method

Abstract Mass transfer limitations may considerably affect the rate of a heterogeneous catalytic process. The catalyst effectiveness factor is a quantitative measure of the impact of the diffusion process inside a catalyst particle. The effectiveness factor is derived from the solution of the steady-state reaction-diffusion problem. Herein, we simulate the steady-state reaction-diffusion equation with space-fractional derivative and linear reaction kinetics. The solution to the problem is obtained numerically using the Haar wavelet collocation method. The effect of the anomalous diffusion exponent on the catalyst effectiveness factor and process parameters, e.g. reactor volume and catalyst mass, is demonstrated. We anticipate that the process efficiency will be notably improved by changing the diffusion regime from standard to superdiffusive.

The role of electrode potential in CaCO3 scaling on steel surfaces under cathodic and corrosion conditions

The role of electrode potential in CaCO3 scaling behavior and kinetics on carbon steel and stainless steel surfaces is investigated through electrochemical tests, surface characterization, and numerical modeling. Under cathodic conditions, calcite is the dominant CaCO3 polymorph, its lateral growth on steel surfaces follows exponential kinetics. However, under gradually promoted corrosion conditions of carbon steel, the presence of corrosion products induces more aragonite deposition and inhibits the lateral growth of CaCO3 scale, gradually evolving from exponential to linear kinetics. This work provides further insight into how the cathodic and anodic reactions of steel corrosion respectively promote and inhibit CaCO3 scaling.

Wodyetia bifurcata (foxtail palm tree) leaves as a super-augmented instantaneous methylene blue remover from simulated water and wastewater.

Wodyetia bifurcata, also known as foxtail palm tree leaves, was tested for highly effective methylene blue (MB) removal from commercial and artificial effluent. BET surface area measurement, FESEM, FTIR, and pHzpc were used to get information on the shape and structure of the particles. Several important factors were used to determine its adsorption activity, including intake concentration, contact duration, and pH level. Accelerated adsorption is seen in the experimental results, with more than 94% adsorption occurring successfully in the initial 12min and reaching equilibrium within 15min (% removal = 97.45%) at neutral pH. It was discovered that the maximum adsorption capacity was 58.74mgg-1 at 308K. The adsorption procedure confirms an active adsorption process of linear and non-linear kinetics of pseudo-second order, and the adsorption path is well addressed by the Freundlich model both in linear and non-linear form, having an R2 value close to unity. Thermodynamic characteristics point to an exothermic, viable, spontaneous reaction with higher entropy. Utilizing a 1:1 MeOH/H2O ratio, spent adsorbent may be readily regenerated by as much as 75% with a possible three-cycle usage. The practical application of biosorbents was confirmed by real-time effectiveness testing using MB-carrying industrial wastewater, and up to 45.75% adsorption was shown. A relative standard deviation confirmed statistical dependability. All things considered, the current material provides a clean and environmentally friendly way to remove MB dye from various wastewater types.

A Non‐Linear Model for Multiple Alcohol Intakes and Optimal Designs Strategies

ABSTRACTThis study addresses the complex dynamics of alcohol elimination in the human body, very important in forensic and healthcare areas. Existing models often oversimplify with the assumption of linear elimination kinetics, limiting practical application. This study presents a novel non‐linear model for estimating blood alcohol concentration after multiple intakes. Initially developed for two different alcohol incorporations, it can be straightforwardly extended to the case of more intakes. Emphasising the significance of accurate parameter estimation, the research underscores the importance of precise experimental design, utilising optimal experimental design (OED) methodologies. Sensitivity analysis of model coefficients and the determination of D‐optimal designs, considering correlation structures among observations, reveal a strong linear relationship between support points. This relationship can be used to obtain nearly optimal designs that are highly efficient and much easier to compute.

Adsorption and photocatalytic degradation of 2,4-dicholrophenol using surgical mask derived SMAC-Fe2O3 composite; adsorption isotherms, kinetics, thermodynamics.

Hybrid material of surgical mask activated carbon (SMAC) and Fe2O3 (SMAC-Fe2O3) composite was prepared by simple co-precipitation method and used as potential material for the remediation of 2,4-dicholrophenol (2,4-DCP). The XRD patterns exhibited the presence of SMAC and Fe2O3, FTIR spectrum showed the FeO-carbon stretching at the wavenumber from 400 to 550cm-1. UV-Vis DRS results showed the band gap was 1.97eV and 2.05eV for SMAC-Fe2O3 and Fe2O3, respectively. The SEM images revealed that the Fe2O3 doped onto the fiber morphology of SMAC. The outcomes of the BET examination exhibited a surface area of 195 m2/g and a pore volume of 0.2062 cm3/g for the SMAC/Fe2O3 composite. The batch mode study shows the maximum adsorption and photocatalytic degradation efficacies which were 97% and 78%, respectively. The experimental data was studied with both linear and nonlinear adsorption isotherm and kinetics models. The nonlinear Langmuir isotherm and pseudo-second-order kinetics (PSOK) models have well fit compared with other models. The Langmuir maximum adsorption capacity (qmax) was found 161.60mg/g. Thermodynamic analysis shows that the 2,4-DCP adsorption onto SMAC-Fe2O3 was a spontaneous and exothermic process. The PSOK assumes that the adsorption process was chemisorption. The photocatalytic degradation rate constant of 2,4-DCP was calculated using pseudo-first-order kinetics (PFOK) and the rate constant for SMAC-Fe2O3 and Fe2O3 were 0.859 × 10-2min-1 and 0.616 × 10-2min-1, correspondingly. In addition, the obtained composite exhibited good reusability after a few cycles. These results confirmed that SMAC-Fe2O3 composite is an effective adsorbent and photocatalyst for removing 2,4-DCP pollutants.

Removal of crocein orange G from water solutions by trimetallic nanoparticles [Co/Cu/M (M=Ni, Zn)] prepared by chemical reduction method

Co-Cu-Ni and Co-Cu-Zn trimetallic nanoparticles (NPs) were prepared by chemical reduction method which were then used as adsorbent to remove Crocein Orange G dye from solution. The elemental composition of the fabricated NPs was determined by EDX analysis, surface morphology was assessed by SEM, and its crystalline nature was confirmed by XRD analysis. The functional groups on nanoparticles were confirmed by FT-IR analysis. The optimum dosage was found to be 0.01 g. Langmuir model as well as linear pseudo 2nd order kinetics models best explained the obtained data. The maximum adsorption capabilities were found to be around 497.618 mg/g and 683.093 mg/g, respectively for Co-Cu-Ni and Co-Cu-Zn trimetallic NPs. The adsorption process was exothermic, as evidenced from the positive ΔH° values. The negative values of ΔG° at the corresponding temperatures support the spontaneous nature of the adsorption processes. The positive entropy changes (ΔS°) suggested that there is more disorderness at the interface between the solid and the solution during the adsorption. The fabricated trimetallic nanoparticles have effectively adsorbed Crocein Orange G, which may be considered as an attractive option in wastewater treatment and environmental remediation applications due to diversity of metal ions on surface offering differential attractive forces for pollutant.

Modeling Electrode Shape Changes in Electrodeposition and Electrochemical Dissolution

In the fields of metal production, surface finishing, and electronic device manufacturing, achieving precise control over electrochemical processes is crucial for product quality, efficiency, and cost-effectiveness. This paper introduces an open-source modeling tool based on a dynamic mesh technique built on the finite volume method using the C ++ toolbox OpenFOAM. This tool has been validated against both newly proposed analytical solutions and existing numerical and experimental results in various conditions and kinetic controls. The analytical solution predicts the electrode surface position, current, or cell voltage difference for confined electrodes. It considers primary and secondary current distributions with linear kinetics under different electric control modes. Notably, the validation highlights the congruence of the new method with prior studies and underscores its potential to offer enhanced predictive capabilities. Furthermore, this work extends beyond traditional modeling approaches by incorporating pulse reverse plating, which has been successfully modeled using the dynamic mesh method. Additionally, a modified Wagner number (WaPR) is proposed to predict in advance the optimal conditions for achieving a more uniform deposit. This innovative approach contributes to the advancement of theoretical understanding and will improve practical applications in electrochemical deposition and dissolution processes.

Development and validation of a liquid chromatography-tandem mass spectrometry method for simultaneous quantification of eight Xiakucao Oral liquid-related compounds in rat plasma and its application in pharmacokinetic study.

Xiakucao Oral Liquid (XKCOL) has been widely used for treating mammary gland hyperplasia and goiter in China. However, its pharmacokinetic data have been missing to date. To conduct its pharmacokinetic study, we established an LC-tandem mass spectrometry method for the simultaneous determination of eight XKCOL-related compounds in rat plasma. Liquid-liquid extraction was used for the sampling process. Chromatographic separation was performed on a Phenomenon Luna C18 column with a mobile phase of methanol and 2 mM ammonium acetate, using gradient elution at a flow rate of 0.8 mL/min. Detection was performed in the multiple reaction monitoring mode using negative electrospray ionization (ESI-) with optimized MS parameters. Endogenous substances and carryover did not interfere in the detection of analytes. The calibration curves showed a good linear relationship within the linear ranges. The intra- and inter-batch accuracy and precision were 94.8%-110.0% and ≤11.2%, respectively. There was no significant matrix effect and the recovery was reproducible. The dilution of samples did not affect the accuracy and precision. The solution and plasma samples were stable under the various test conditions. The major components of XKCOL absorbed into the blood were salvianic acid A and rosmarinic acid. They demonstrated linear kinetics over the dose range used in this study.

Fast decomposition of organic contaminant in wastewater using Zn and Mn bimetallic metal organic frameworks

Metal-organic frameworks (MOFs) exhibit remarkable versatility across various applications including luminescence sensors, adsorption, gas separation, and catalysis due to their tuneable structure and characteristics, especially in the presence of mono- or bi-metal ions. In this study, a comparative analysis of solvothermally synthesized zinc MOF (MOF-5), manganese MOF (Mn-MOF), and bimetallic zinc-manganese MOF (Zn/Mn-MOF) is conducted. Clear distinctions in the properties of these synthesized materials are observed. XRD spectra suggest that MOF-5 and Zn/Mn-MOF exhibit higher crystallinity compared to Mn-MOF. FESEM images reveal that particles of bimetallic MOFs are well-separated, whereas those of monometallic MOF-5 and Mn-MOF are agglomerated. Zn/Mn-MOF display the lowest band gap, measuring 3.03 eV. To assess their efficacy as photocatalysts, their ability to degrade methylene blue under simulated sunlight is evaluated. Reaction kinetics indicate that degradation follows pseudo-first-order linear kinetics for all synthesized samples. Notably, bimetallic Zn/Mn-MOF outperforms its monometallic counterparts in dye degradation processes, exhibiting a rate constant of 0.0535 min−1 and an exceptional degradation rate of ∼91 % in 120 min. Dark condition experiments suggest minimal dye adsorption by the synthesized MOFs, with values of 8.2 %, 5 %, and 2.5 % after 120 min for MOF-5, Mn-MOF, and Zn/Mn-MOF, respectively. Irradiation of the dye solution with a solar simulator enhances methylene blue decomposition. Furthermore, the recyclability studies for MB dye degradation by the Zn/Mn MOF reveal a decline in photocatalytic efficiency to 71.3 % after the fourth cycle, indicating appreciable stability of the material.

Insect‐Inspired Drones: Adjusting the Flapping Kinetics of Insect‐Inspired Wings Improves Aerodynamic Performance

Insects flap their wings through a highly specialized musculoskeletal system that allows the wings to rotate about three degrees of freedom. Consequently, the wingtip trajectory is adjustable in 3D, and accompanied with appropriate wing feathering (wing pitch). Remarkably, the complex flapping motion is achieved by thoracic muscles acting on the wing hinge. The wings themselves do not possess muscles but adjust their shape and orientation by elastically deforming due to the loads applied on them during flapping. Previous attempts to develop insect‐inspired flapping drones have mostly focused on simplified linear flapping mechanisms, which do not utilize the interaction between the wing flexibility and flapping kinematics to its full potential. Here, the aim is to improve flapping drones’ performance by introducing mechanisms that mimic insects’ flight. The first is an elastic beam mechanism, allowing the wing root to swing during flapping, and the second is a passive wing pitch mechanism that allows the wing to rotate at stroke reversals. The two mechanisms are tested using high‐fidelity insect‐inspired 3D‐printed wings and show a sixfold improvement of aerodynamic performance compared to linear flapping kinetics of the same flexible wings. This underscores the necessity of bioinspired flapping mechanisms in future flapping drones.

Implementing the Blowers-Masel Approximation to Scale Activation Energy Based on Reaction Enthalpy in Mean-Field Microkinetic Modeling for Catalytic Methane Partial Oxidation.

Mean-field microkinetic modeling is a powerful tool for catalyst design and the simulation of catalytic processes. The reaction enthalpies in a microkinetic model often need to be adjusted when changing species' binding energies to model different catalysts, when performing thermodynamic sensitivity analyses, and when fitting experimental data. When altering reaction enthalpies, the activation energies should also be reasonably altered to ensure realistic reaction rates. The Blowers-Masel approximation (BMA) relates the reaction barrier to the reaction enthalpy. Unlike the Brønsted-Evans-Polani relationship, the BMA requires less data because only one parameter, the intrinsic activation energy, needs to be determined. We validate this application of BMA relations to model surface reactions by comparing against density functional theory data taken from the literature. By incorporating the BMA rate description into the open-source Cantera software, we enable a new workflow, demonstrated herein, allowing rapid screening of catalysts using linear scaling relationships and BMA kinetics within the process simulation software. For demonstration purposes, a catalyst screening for catalytic methane partial oxidation on 81 hypothetical metals is conducted. We compared the results with and without BMA-corrected rates. The heat maps of various descriptors (e.g., CH4 conversion, syngas yield) show that using BMA rates instead of Arrhenius rates (with constant activation energies) changes which metals are most active. Heat maps of sensitivity analyses can help identify which reactions or species are the most influential in shaping the descriptor map patterns. Our findings indicate that while using BMA-adjusted rates did not markedly affect the most sensitive reactions, it did change the most influential species.

Guar gum, Ulva lactuca L. biomass, and xanthan gum-based copolymer novel biosorbent for adsorptive removal of acid orange 10

The textile industry's wastewater discharge into water bodies has become a significant environmental concern due to its toxicity and adverse impact on the ecosystem. In response, this study presents the development of a highly effective adsorbent (GG@ULB@XG composites) by employing guar gum (GG), Ulva lactuca L. biomass (ULB), and xanthan gum (XG), using the ionic gelation method. Various characterization techniques including XRD, SEM, TGA, Zeta Sizer, Zeta Potential, BET, FTIR, and Point of Zero charge (pHPZC) were utilized to analyze the properties of the GG@ULB@XG composites. The removal efficiency of the composite for Acid Orange 10 dye was found to be exceptional, achieving a remarkable 93% removal rate. Optimal adsorption parameters were determined, including initial AO10 concentration (100 ppm), temperature (298K), pH (3), adsorbent concentration (100 mg), and contact time (15 min) at 480 λmax. The thermodynamic analysis provided valuable insights into the thermal stability of the adsorbent. Additionally, a comprehensive investigation of adsorption isotherms (linear and non-linear), such as Elovich, Freundlich, D-R, Langmuir, and Temkin Isotherms, was conducted to better understand the adsorption behavior. Various linear and non-linear adsorption kinetics models, including Elovich, first-order, interparticle diffusion, and second-order kinetic models, were employed to gain deeper insights into the chemistry of the adsorption process. This study highlights the potential of GG@ULB@XG composites as an effective and environmentally friendly solution for water treatment and dye removal in industrial wastewater and sets a foundation for future studies in the field of environmental remediation.

Modeling the subcutaneous pharmacokinetics of antibodies co-administered with rHuPH20.

Predicting the subcutaneous (SC) pharmacokinetics (PK) of antibodies in humans is challenging, with clinical data currently being the only reliable data source for modeling SC absorption and bioavailability. Recombinant human hyaluronidase PH20 (rHuPH20) is an enzyme that facilitates SC delivery of high-dose, high-volume therapeutics. Numerous monoclonal antibodies have been co-administered SC with rHuPH20 in a clinical setting, establishing an extensive PK database. The goal of this work is to demonstrate how aggregated clinical data can be leveraged in a universal modeling framework for characterizing SC antibody PK, resulting in parameterization that can be used in predictive simulations of new antibodies. Data for 10 individual antibodies co-administered SC with rHuPH20 were obtained from publicly available sources. PK modeling of each antibody was conducted using the same model structure, but uniquely parameterized. The model structure consisted of a two-compartment model to capture linear kinetics, plus a target-binding mechanism to accommodate nonlinear kinetics driven by antibody-target complex formation and elimination. The clinical PK profiles for all antibodies were accurately described using the universal modeling framework. The SC PK parameters of absorption and bioavailability were consistent across the range of antibody and target properties evaluated. SC administration with rHuPH20 yielded a 30% increase in absorption rate on average and similar or better bioavailability. These parameter values can serve as initial conditions for model-based PK predictions for new antibodies co-administered SC with rHuPH20 to enable evaluation of optimal SC dose and schedule regimens prior to and during clinical development.

Accelerating therapeutics development during a pandemic: population pharmacokinetics of the long-acting antibody combination AZD7442 (tixagevimab/cilgavimab) in the prophylaxis and treatment of COVID-19.

AZD7442 is a combination of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-neutralizing antibodies, tixagevimab and cilgavimab, developed for pre-exposure prophylaxis (PrEP) and treatment of coronavirus disease 2019 (COVID-19). Using data from eight clinical trials, we describe a population pharmacokinetic (popPK) model of AZD7442 and show how modeling of "interim" data accelerated decision-making during the COVID-19 pandemic. The final model was a two-compartmental distribution model with first-order absorption and elimination, including standard allometric exponents for the effect of body weight on clearance and volume. Other covariates included were as follows: sex, age >65 years, body mass index ≥30 kg/m2, and diabetes on absorption rate; diabetes on clearance; Black race on central volume; and intramuscular (IM) injection site on bioavailability. Simulations indicated that IM injection site and body weight had > 20% effects on AZD7442 exposure, but no covariates were considered to have a clinically relevant impact requiring dose adjustment. The pharmacokinetics of AZD7442, cilgavimab, and tixagevimab were comparable and followed linear kinetics with extended half-lives (median 78.6 days for AZD7442), affording prolonged protection against susceptible SARS-CoV-2 variants. Comparison of popPK simulations based on "interim data" with a target concentration based on 80% viral inhibition and assuming 1.81% partitioning into the nasal lining fluid supported a decision to double the PrEP dosage from 300 mg to 600 mg to prolong protection against Omicron variants. Serum AZD7442 concentrations in adolescents weighing 40-95 kg were predicted to be only marginally different from those observed in adults, supporting authorization for use in adolescents before clinical data were available. In these cases, popPK modeling enabled accelerated clinical decision-making.

Sunlight-Driven Photochemical Removal of Polypropylene Microplastics from Surface Waters Follows Linear Kinetics and Does Not Result in Fragmentation.

Floating microplastics are susceptible to sunlight-driven photodegradation, which can convert plastic carbon to dissolved organic carbon (DOC) and can facilitate microplastic fragmentation by mechanical forces. To understand the photochemical fate of sub-millimeter buoyant plastics, ∼0.6 mm polypropylene microplastics were photodegraded while tracking plastic mass, carbon, and particle size distributions. Plastic mass loss and carbon loss followed linear kinetics. At most time points DOC accumulation accounted for under 50% of the total plastic carbon lost. DOC accumulation followed sigmoidal kinetics, not the exponential kinetics previously reported for shorter irradiations. Thus, we suggest that estimates of plastic lifespan based on exponential DOC accumulation are inaccurate. Instead, linear plastic-C mass and plastic mass loss kinetics should be used, and these methods result in longer estimates of photochemical lifetimes for plastics in surface waters. Scanning electron microscopy revealed that photoirradiation produced two distinct patterns of cracking on the particles. However, size distribution analyses indicated that fragmentation was minimal. Instead, the initial population of microplastics shrank in size during irradiations, indicating photoirradiation in tranquil waters (i.e., without mechanical forcing) dissolved sub-millimeter plastics without fragmentation.

Comparative study on the oxidation behavior of Si2BC3N/Ta4HfC5 ceramics at 1000 °C and 1500 °C: Microstructural evolution and kinetics consideration

The oxidation kinetics and oxide scale morphology of the Si2BC3N/Ta4HfC5 ceramics sintered by hot-pressing were explored at 1000 °C and 1500 °C in flowing air. Dense Si2BC3N/Ta4HfC5 ceramic sintered at 1900 °C with fine grain sizes shows the optimal oxidation resistance both at 1000 °C and 1500 °C. When oxidized at 1000 °C, the formation of a porous oxide layer of Ta2O5, Hf6Ta2O17 and HfO2 containing amorphous SiO2 are primarily responsible for the unsatisfying oxidation resistance of the composite. A highly oxidation resistance component like Si2BC3N can promote the oxidation resistance of Ta4HfC5 at 1500 °C, thanks to the formation of a dense and continuous tantalum-hafnium silicate glass. The oxidation kinetic curve at 1500 °C can be described by a parabolic law whilst the oxidation process is controlled by the diffusion rate of oxygen through the oxide layer; however, the oxidation reaction rate governs the oxidation progress at 1000 °C via a linear oxidation kinetics.

Characteristics of the linear kinetic curve for the dimensions of movement and its effect on the completion of the kinematic duty of the spiking skill from the center (3) of the volleyball from sitting


 The study focused on the importance of spiking skill from position (3) in the game of volleyball from sitting because it has a role in deciding the results of matches and dealt with the importance of using modern laboratory devices (BUSAN system) in detecting the values of linear kinetics variables and their effective impact on Training and making use of it in developing skills, It also aimed to try to identify the characteristics of linear kinetics for dimensional movement and the kinetic duty of the players who hit the center (3) in the game of volleyball from sitting. Because using these numerical values in the training process has many benefits and functions, One of the most important of them is identifying the correct kinematic pathways for accuracy of the blow and other important benefits that work to achieve the greatest possible training and educational competence. In addition to saving the effort and time spent in the training unit, the researcher used the descriptive approach and identified the research community, which is the national volleyball team from sitting, and deliberately chose the players who perform the crushing beating from Center (3) and their number (10) As for the most important conclusions, the results showed the importance of providing information about the chain of forces during the performance in the main stage and then making use of it in explaining the movement. The results of the characteristics of the (linear) kinetic curve of the variables of the power chain showed a consistent shape in the main stage (crushing) with the volleyball from sitting for parts The body and each according to the amount of its mass and its contribution to the multiplication stage.