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The current study investigates the production of organoclay suitable for use in the base section of a passenger tire with a cap/base tread construction. The process involved the purification and modification of two types of sodium bentonite clay with different mineral characteristics and ion exchange capacities using a single-step process. The modification process of purified bentonite suspensions was performed using a two-tailed long-chain alkyl quaternary ammonium salt surfactant, namely di (hydrogenated tallow alkyl) dimethyl ammonium chloride (AD2HT), and two one-tailed long-chain alkyl quaternary ammonium salt surfactants, namely cetyl-trimethylammonium chloride (CTAC) and octadecylamine chloride (ODA), in relatively low amounts of surfactant (0.95 CEC), along with polyethylene glycol (4% clay) as an auxiliary modifier. X-ray diffraction (XRD) showed that the interlayer spacing of organoclays significantly increases. In addition, the XRD pattern depends on the kind of surfactant and is independent of the type of bentonite clay. The resulting organoclays were added to the tread base section of a passenger tire using the melt masterbatch technique along with a silane coupling agent. An increase in curing maximum torque (8–15%), curing delta torque (6–14%), hardness (2–10%), static modulus 300 (2–18%), and dynamic storage modulus (11–30%) of the rubber composites was observed without significant change of resilience and loss factor of the composite at 2 Phr of organoclay loadings. The organoclays based on the AD2HT modifier exhibited better mechanical properties than those based on the ODA and CTAC surfactants. The dynamic storage modulus of composites increased by about 30% with only 2 Phr of AD2HT-modified bentonites. Furthermore, the performance of the organoclay was found to be independent of the primary particle size, iron content, and ion exchange capacity of the bentonite clay within the studied range. [ABSTRACT FROM AUTHOR]

The development of a heat conductive formulation for rubber composites is essential for technical applications such as tire-curing bladders. The present study addresses the effects of three potential ceramic fillers, namely titanium carbide (TiC), silicon carbide (SiC), and alumina, on the mechanical and thermal properties of carbon black (CB)-filled butyl rubber composites. The composites were prepared using the melt compounding method. The curing, mechanical, and thermal conductivity properties of the composites were determined. The tensile strength and modulus of composites decreased slightly in the presence of ceramic fillers in lower amounts of filler loading (10 Phr). Further they reduced in a higher amount of filler loading (20 Phr). In addition, the thermal diffusivity coefficient of the composites increased in the presence of ceramic fillers with different values depending on the type and the amount of the filler with the rank of Al2O3 > SiC > TiC at 10 Phr of filler loading and SiC > TiC > Al2O3 at 20 Phr of filler loading. These different behaviors were discussed according to the state of filler dispersion in the rubber matrix and rubber–filler interactions according to the FeSEM visualization and the mechanical properties. [ABSTRACT FROM AUTHOR]

Regression analysis based on data from Oxford COVID-19 Government Response Tracker and the World Bank datasets for 169 countries suggests that containment policies have, in general, a significant role in reducing the pandemic's fatality rate across all countries. However (i) there is at least a three weeks lag in realising the impact, (ii) the effectiveness increases with per capita income and, more specifically, (iii) workplace closure is ineffective in low-income countries. The analysis of data from Demographic and Health Survey (the DHS Programme) and IMF Policy Tracker indicates that developing countries are unlikely to have the basis required for effectively adopting stringent lockdown measures and instead would need to consider specifically targeted lockdown policies. [ABSTRACT FROM AUTHOR]

Objective: To prospectively assess clinical and cost effectiveness of emergency ureteroscopic laser fragmentation of urinary stones causing symptoms or obstruction. Patients and methods: 100 consecutive patients with an average (median) age 55.6 (57.5) years and average (median) stone size of 8.2 mm (± 7 mm) between October 2018 and December 2021 who underwent emergency ureteroscopy and laser fragmentation formed the study cohort as part of a clinical service quality improvement. Primary outcome was single procedure stone-free rate and cost-effectiveness. The secondary outcomes were complications, re-admission and re-intervention. A decision analysis model was constructed to compare the cost-effectiveness of emergency ureteroscopy with laser fragmentation (EUL) and emergency temporary stenting followed by delayed ureteroscopy with laser fragmentation (DUL) using our results and success rates for modelling. Results: Single procedure stone-free rates (SFR) for EUL and DUL were 85%. The re-intervention rate, re-admission and complication rates of the study cohort (EUL) were 9%, 18%, and 4%, respectively, compared to 15%, 20%, and 5%, respectively for the control cohort (DUL). The decision analysis modelling demonstrated that the EUL treatment option was more cost-efficient, averting £2868 (€3260) per patient for the UK health sector. Total cost of delayed intervention was £7783 (€8847) for DUL in contrast to £4915 (€5580) for EUL. Conclusions: Implementation of quality improvement project based on a reduction in CT detection-to-laser fragmentation time interval in acute ureteric obstruction or symptoms caused by stones had similar clinical effectiveness compared to delayed ureteroscopic management, but more cost-effective. [ABSTRACT FROM AUTHOR]

Objective To prospectively assess clinical and cost effectiveness of emergency ureteroscopic laser fragmentation of urinary stones causing symptoms or obstruction. Patients and methods 100 consecutive patients with an average (median) age 55.6 (57.5) years and average (median) stone size of 8.2 mm (± 7 mm) between October 2018 and December 2021 who underwent emergency ureteroscopy and laser fragmentation formed the study cohort as part of a clinical service quality improvement. Primary outcome was single procedure stone-free rate and cost-effectiveness. The secondary outcomes were complications, re-admission and re-intervention. A decision analysis model was constructed to compare the cost-effectiveness of emergency ureteroscopy with laser fragmentation (EUL) and emergency temporary stenting followed by delayed ureteroscopy with laser fragmentation (DUL) using our results and success rates for modelling. Results Single procedure stone-free rates (SFR) for EUL and DUL were 85%. The re-intervention rate, re-admission and complication rates of the study cohort (EUL) were 9%, 18%, and 4%, respectively, compared to 15%, 20%, and 5%, respectively for the control cohort (DUL). The decision analysis modelling demonstrated that the EUL treatment option was more cost-efficient, averting £2868 (€3260) per patient for the UK health sector. Total cost of delayed intervention was £7783 (€8847) for DUL in contrast to £4915 (€5580) for EUL. Conclusions Implementation of quality improvement project based on a reduction in CT detection-to-laser fragmentation time interval in acute ureteric obstruction or symptoms caused by stones had similar clinical effectiveness compared to delayed ureteroscopic management, but more cost-effective. [ABSTRACT FROM AUTHOR]

Highlights: [•] Application of the response surface models in CO hydrogenation to light olefins has been studies. [•] Catalyst was a Fe–Co–Mn prepared with precipitation method. [•] A quadratic polynomial for CO hydrogenation and alkene yields was successfully fitted to the experimental data. [•] The RSM simulated data were also employed to kinetic study of CO hydrogenation. [•] A rate equation based on direct reaction of hydrogen from gas phase with molecularly adsorbed CO were proposed. [ABSTRACT FROM AUTHOR]

Abstract: In this article the application of design of experiment coupled with artificial neural networks in kinetic study of CO hydrogenation reaction and a method of data collection/fitting for the experiment are presented. The kinetic experimental data has been collected from two factors of central composite designs, pressure and feed ratio in different temperatures. Response surface and artificial neural network models have been constructed based on the DOE points and used for generating simulated data. Then different data sets were used to fit LHHW kinetic rates of CO disappearance. The application of the neural networks to solve the problem of correlation of the rate equation parameters has been addressed. The results of kinetic modeling with simulated data sets from ANN and RSM models were compared with randomly collected experimental and the DOE data sets. It was observed that three rate equations were able to fit the data sets and kinetic modeling with the proposed DOE-based and simulated data, are very efficient for assessing the quality of the models. However, conducting kinetic modeling with ANN simulated data presented the best results. [Copyright &y& Elsevier]

The effect of adding MgO to a precipitated iron-cobalt-manganese based Fischer-Tropsch synthesis (FTS) catalyst was investigated via response surface methodology. The catalytic performance of the catalysts was examined in a fixed bed micro reactor at a total pressure of 1-7 bar, temperature of 280-380°C, MgO content of 5-25% and using a syngas having a H2 to CO ratio equal to 2. The dependence of the activity and product distribution on MgO content, temperature, and pressure was successfully correlated via full quadratic second-order polynomial equations. The statistical analysis and response surface demonstrations indicated that MgO significantly influences the CO conversion and chain growth probability as well as ethane, propane, propylene, butylene selectivity, and alkene/alkane ratio. A strong interaction between variables was also evidenced in some cases. The decreasing effect of pressure on alkene to alkane ratio is investigated through olefin readsorption effects and CO hydrogenation kinetics. Finally, a multiobjective optimization procedure was employed to calculate the best amount of MgO content in different reactor conditions. [ABSTRACT FROM AUTHOR]

In this study, an application of artificial neural network (ANN) has been presented in modeling and studying the effect of compounding variables on abrasion behavior of rubber formulations. Three case studies were carried out in which the experiment data were collected according to classical response surface designs. Besides developing the ANN models, we developed response surface methodology (RSM) to confirm the ANN predictions. A simple relation was employed for determination of relative importance of each variable according to ANN models. It was shown through these case studies that ANN models delivered very good data fitting and their simulating curves could help the researchers to better understand the abrasion behavior. [ABSTRACT FROM AUTHOR]

This study reports photocatalytic degradation of ciprofloxacin (CIP) in the presence of silver nanoparticles impregnated over amorphous silica extracted from rice husk through a green approach using Melia Azedarach fruit extract. Various analyses such as X-ray diffraction analysis (XRD), Fourier-transform infrared (FTIR) spectroscopy, and field emission scanning electron microscopy (FESEM) were employed to characterize the obtained nanocomposite. Afterward, the photocatalytic activity of the nanocomposite was studied in the removal of CIP from an aqueous solution under natural sunlight irradiation. Moreover, the effect of various parameters such as solution initial pH (3–11), reaction time (30–180min), and catalyst loading (0.03–0.12 g) on degradation efficiency were studied by applying a design of experiment (DOE) methodology. The results indicated the successful synthesis and deposition of Ag nanoparticles over amorphous silica. The results of degradation experiment confirmed the acceptable performance of Ag/silica nanocomposite in photo-degradation of CIP. According to the experimental design, both catalyst loading and reaction time are highly significant; whereas the initial pH is not significant compared to other factors. Moreover, the optimal conditions were determined to be initial pH = 6.7, reaction time = 180 min, and catalyst loading of 0.12 g. By applying these optimal conditions, degradation efficiency reached to 98%. Moreover, the results of kinetic study revealed that the photo-degradation of CIP in presence of Ag/silica nanocomposite obeys a first-order kinetic model. The Ag/silica nanocomposite exhibited a high level of stability as the nanocomposites could preserve their stability after three sequential degradation cycles. [Display omitted] [ABSTRACT FROM AUTHOR]

An attempt was made to non-isothermal kinetic modeling of the sulfur curing reaction of carbon black filled tyre tread composite in the presence of high dispersible silica (HDS) and alumina or boehmite filler. The results displayed the chance of a reduction occurs in the parts curing time due to increase in the thermal conductivity of the rubber, which using carbon black/silica/alumina or carbon black/silica/boehmite ternary filler. This key feature, with acceptable mechanical properties and the enhanced dynamic behavior give a high potential as a novel filler in rubber parts, including tyre treads. Image 1 • Heat conductivity of tire tread formulation was increased with some substitution of carbon black with high dispersible silica - alumina and high dispersible silica-alumina binary filler. • The mechanical properties of the composite were not changed in the presence of ternary blend filler. • The non-isothermal curing time of the composites were determined with a combined experimental simulation approach for composites filled with carbon black and new filler system. [ABSTRACT FROM AUTHOR]