Sectional Analysis Procedure for Reinforced Concrete Members Subjected to Pure Torsion

A sectional analysis procedure for reinforced concrete members subjected to pure torsion is presented in this paper. On the development of the analysis procedure, the reinforced concrete section is modeled with reinforced concrete elements subjected to biaxial stress states, on the basis of the thin-walled tube analogy. Each reinforced concrete element is analyzed with the modified compression field theory (MCFT) to take into account for compression softening and tension stiffening effects in cracked reinforced concrete. Considering analysis results of reinforced concrete elements, equilibrium, and compatibility on the section are checked. For verification of the developed analysis procedure, analytical predictions were compared with test results of 16 reinforced concrete beams subjected to a pure torsional load which are available in the literature. Comparison between predicted and experimentally obtained torque-twist responses showed that the proposed procedure is capable of capturing the ultimate torsional capacity as well as the angle of twist within a reasonable range

On the effects of fractal geometry on reacting and nonreacting flows in a low-swirl burner: A numerical study with large-eddy simulation

Understanding and optimizing turbulence in combustion systems has a profound effect on combustion efficiency, emission reduction, and safety in applications ranging from industrial burners to propulsion systems in aerospace. This paper contributes to this pivotal field by investigating a real-scale low-swirl combustor utilizing a range of turbulence generation plates characterized by different blockage ratios and numbers of fractal pattern iterations. The work encompasses two states, namely nonreacting and premixed reacting modes, utilizing a large-eddy simulation method equipped with a dynamic Smagorinsky sub-grid model and adaptive mesh refinement for high accuracy. Verifying the robustness of the approach, the simulation aligns closely with experimental data, registering a maximum error of less than 0.9% in the swirl number. The research provides an insightful evaluation of the impact of four different fractal geometries on turbulence intensity, a vital element for attaining more complete combustion. Findings indicate a fractal with a 73% blockage ratio and four iteration levels enhances several key parameters including turbulence intensity, flow residence time, vorticity, and velocity gradient in the nonreacting mode. Conversely, a fractal with a 73% blockage ratio and three iteration levels shows the least progress in the reacting mode. Moreover, the paper delves into a comparative analysis of these two cases in the reacting mode, particularly observing the reaction zone. The appropriate fractal geometry unveiled significantly improves combustion efficiency, evidenced by an increased presence of the OH radical and a decrease in NO emission gas, thus demonstrating potential for wider application in enhancing combustion systems

Ambulatory blood pressure response to S‐amlodipine in Korean adult patients with uncontrolled essential hypertension: A prospective, observational study

Abstract Although amlodipine is recommended as the first‐line therapy for the treatment of hypertension, its use is limited by its potential side effects. S‐amlodipine is expected to be able to minimize side effects of amlodipine with a similar antihypertensive effect by removing the malicious R‐chiral form. However, sustainable blood pressure control with S‐amlodipine has not been well established yet. The purpose of the current study was to evaluate ambulatory blood pressure (ABP) profiles before and after a 12‐week treatment of S‐amlodipine. Patients received once‐daily S‐amlodipine 2.5 or 5 mg. ABP during 24 hr and office blood pressure were measured at baseline and after the 12‐week treatment. Primary endpoints were changes of systolic and diastolic 24 hr ABP. After 12‐week S‐amlodipine treatment, mean systolic ABP (‐15.1 ± 16.2 mmHg, p < .001) and diastolic ABP (‐8.9 ± 9.8 mmHg, p < .001) were decreased significantly. Both daytime and night‐time mean systolic BP and diastolic BP were also significantly decreased after the 12‐week treatment. Global trough‐to‐peak ratio and smoothness index after 12‐week S‐amlodipine treatment were .75 and .79 for SBP and .65 and .61 for DBP, respectively. Age ≥65 years (hazard ratio [HR]: 3.13; 95% confidence interval [CI]: 1.67–14.3) and nonalcohol drinking (HR: 3.09; 95% CI: 1.34–7.17) were independent clinical factors for target ABP achievement. Adverse drug reactions (ADR) were developed in 16 (6.4%) patients, including two (.8%) cases of peripheral edema. In conclusion, this study demonstrated the efficacy and safety of S‐amlodipine in patients with uncontrolled essential hypertension