Study on Performance Enhancement of a Flapping Foil Energy Harvester Using Circulation Control

Oscillating motion, an effective way to harvest energy, has gradually become a hotspot in bionic motion research in recent years. Means of improving the energy-extraction efficiency of a flapping foil harvester have long been a focus of researchers. This paper proposes a new flapping foil harvester with circulation control and explores the effects of different parameters on its energy-extraction capacity to improve efficiency and achieve lowest cost. Setting the injection ports on the upper and lower surfaces near the trailing edge of the foil and implementing injection control during motion, the effects of the location of the injection port, pitching amplitude, momentum coefficient, reduced frequency, and jet mode on the circulation control flapping foil are systematically investigated under the condition of a Reynolds number of 13,800. The results show that circulation control can enhance the energy-extraction efficiency of a flapping foil across a wide range of parameters, in which the location of the injection port and momentum coefficient have the most obvious influence on efficiency, followed by pitching amplitude and reduced frequency. In addition, the jet mode is a crucial factor affecting net efficiency. Relative to the constant mode, the triangular mode of circulation control has the lowest energy consumption, and the net energy-extraction efficiency reaches up to 38.77% under a reduced frequency of 0.12, which is 22.24% higher than that of the plain flapping foil.

Investigation of corona discharge ionization of barbituric acid using ion mobility spectrometry along with quantum chemical calculations

This study aimed at examining atmospheric-pressure chemical ionization of barbituric acid through the corona discharge ion mobility spectrometry (CD-IMS) and the quantum chemical calculations. The results indicated two product ion peaks in the IMS spectrum of barbituric acid. The thermal decomposition of the barbituric acid sample was investigated by scanning the temperature of the injection port and analyzing the temporal evolution of the IMS peaks over elapsed time. It was found that the barbituric acid sample was not thermally decomposed in the injection port of the instrument. Experimental evidences were collected by changing the reactant ions, concentration of barbituric acid sample, and IMS cell temperature. The two observed peaks were then assigned to cationic form and oxygen protonated isomers of barbituric acid. The positions of the product ion peaks were explicated considering the dipole moments of the product ions.

Procedural comparison of a standard PTA balloon for fistula and graft maintenance procedures with the novel Chameleon™ PTA balloon catheter

Introduction: The incidence of cephalic arch (CA) and central venous (CV) stenosis has been reported in the range of 30% in the literature. The purpose of this study is to compare contrast use, fluoroscopy time, and procedure time between standard imaging by injection of contrast through the access sheath versus injection of contrast through a novel PTA balloon with an integrated injection port. Methods: A multi-centered, retrospective evaluation of consecutive patients treated for CA and CV stenosis was performed. Data captured included demographics, co-morbidities, lesion characteristics/location, procedural details, volume of contrast used, fluoroscopy time, and procedure time. The control group was imaged and treated using standard practice with pre and post imaging performed through the sheath and intervention using standard PTA balloon. Imaging and treatment were performed using the Chameleon™ PTA catheter in the treatment arm. Results: A total of 68 consecutive patients were included. There were 34 patients in Group A and 34 patients in Group B. Average age was 65.2 versus 66.5 ( p = 0.284), respectively. There were no significant gender differences between groups. Prevalence of co-morbidities of hypertension, coronary artery disease, and diabetes was similar to national rates in both groups. Contrast volume, fluoroscopy time, and procedure time in Group B were significantly less when compared by multiple regression to Group A, correcting for potential confounders ( p = 0.0001, 0.0180, and 0.0008, respectively). Conclusion: Use of a PTA balloon with an integrated injection port shows potential for significant reduction in contrast dose, fluoroscopy time, and procedure time.

Airfoil leading edge blowing to control bow shock waves

This manuscript presents a detailed characterization of active control of bow shock waves via leading edge injection, including subsonic coolant ejection and the appearance of Coanda effects. The flow phenomena occurring at steady and pulsating flow injection regimes were analyzed using steady and unsteady two-dimensional Reynolds-Averaged Navier Stokes, leading to a precise evaluation of the thermal load and drag reductions. Steady supersonic injection yields the largest abatement in thermal load and aerodynamic drag, while subsonic or fluctuating ones can also provide significant improvements at reduced cooling mass flow rates. Furthermore, a Coanda effect, causing a non-symmetric flow topology, was observed and analyzed for reduced injection port size. This Coanda effect is due to the sudden expansion happening from the injection port to the main flow and it causes the flow topology at the leading edge to become non-symmetric despite the complete symmetry of the problem. This is the first time in the literature such a phenomenon is documented for a supersonic airfoil leading edge injection. Furthermore, it enables the design of novel flow control strategies for the leading edge shock topology and flow structures in supersonic flows.

Analytical GC-FID Method for the Determination of Organic Solvents in Radiopharmaceutical

Background:: Organic solvents play an indispensable role in most of the radiopharmaceutical production stages. It is almost impossible to remove them entirely in the final formulation of the product. Objective:: In this presented work, an analytical method by gas chromatography coupled with flame ionization detection (GC-FID) has been developed to determine organic solvents in radiopharmaceutical samples. The effect of injection hold time, temperature variation in the injection port, and the column temperature on the analysis time and resolution (R ≥ 1.5) of ethanol and acetonitrile were studied extensively. Methods:: The experimental conditions were optimized with the aid of further statistical analysis; thence, the proposed method was validated following the International Council for Harmonisation (ICH) Q2 (R1) guideline. Results:: The proposed analytical method surpassed the acceptance criteria for the linearity > 0.990 (correlation coefficient of R2), precision < 2%, LOD, and LOQ, accuracy > 90% for all solvents. The separation between ethanol and acetonitrile was acceptable with a resolution, R > 1.5. Further statistical analysis of Oneway ANOVA revealed that the increment of injection holds time and variation of temperature at the injection port did not significantly affect the analysis time. Nevertheless, the variation of injection port temperature substantially influences the resolution of ethanol and acetonitrile peaks (p < 0.05). Conclusion:: The proposed analytical method has been successfully implemented to determine the organic solvent in the [18F]fluoro-ethyl-tyrosine ([18F]FET), [18F]fluoromisonidazole ([18F]FMISO), and [18F]fluorothymidine ([18F]FLT).