Jet-Induced Blood Release From Human Fingertips: A Single-Blind, Randomized, Crossover Trial

Background: Lancet pricks are often poorly received by individuals with diabetes; jet injection may allow lancet-free blood sampling. We examine whether the technique of jet injection can release sufficient blood from the fingertip to enable measurement of blood glucose concentration. In addition, we assess the effect of jet shape and cross-sectional area on fluid release, blood dilution, and perceived pain. Methods: A randomized, single-blind, crossover study was conducted on 20 healthy volunteers who received interventions on four fingertips: a lancet prick, and jet injection of a small quantity of saline solution through three differently shaped and sized nozzles. Released fluid volume, blood concentration, and glucose concentration were assessed immediately after the intervention. Pain perception and duration, and any skin reactions, were evaluated both immediately and 24 hours after the intervention. Results: Jet injection released sufficient blood from the fingertip to conduct a glucose measurement. A slot-shaped nozzle released the most blood, although less than a lancet, with slightly higher pain. The blood glucose levels estimated from the extracted fluid showed a mean absolute percentage error of 25%. There was no consistent evidence that a jet injection leads to different skin reactions at the intervention site relative to a lancet prick. Conclusions: Fingertip penetration by jet injection can release a volume of fluid sufficient for blood glucose measurement. Jet injection with a slot-shaped nozzle and/or a nozzle with larger outlet area helps to release more fluid. This technique may enable blood sampling, glucose concentration measurement, and insulin delivery to be performed in a single device.

An Efficient Assisted Bidirectional Glenn Design With Lowered Superior Vena Cava Pressure for Stage-One Single Ventricle Patients

Recently, the assisted bidirectional Glenn (ABG) procedure has been proposed as an alternative to the modified Blalock–Taussig shunt (mBTS) operation for neonates with single-ventricle physiology. Despite success in reducing heart workload and maintaining sufficient pulmonary flow, the ABG also raised the superior vena cava (SVC) pressure to a level that may not be tolerated by infants. To lower the SVC pressure, we propose a modified version of the ABG (mABG), in which a shunt with a slit-shaped nozzle exit is inserted at the junction of the right and left brachiocephalic veins. The proposed operation is compared against the ABG, the mBTS, and the bidirectional Glenn (BDG) operations using closed-loop multiscale simulations. Both normal (2.3 Wood units-m2) and high (7 Wood units-m2) pulmonary vascular resistance (PVR) values are simulated. The mABG provides the highest oxygen saturation, oxygen delivery, and pulmonary flow rate in comparison to the BDG and the ABG. At normal PVR, the SVC pressure is significantly reduced below that of the ABG and the BDG (mABG: 4; ABG: 8; BDG: 6; mBTS: 3 mmHg). However, the SVC pressure remains high at high PVR (mABG: 15; ABG: 16; BDG: 12; mBTS: 3 mmHg), motivating an optimization study to improve the ABG hemodynamics efficiency for a broader range of conditions in the future. Overall, the mABG preserves all advantages of the original ABG procedure while reducing the SVC pressure at normal PVR.

Thrust Augmentation of Single Cycle Pulse Detonation Engine using Nozzles

Pulse detonation propulsion systems have the potential to provide better performance with additional advantages such as considerably light in weight, cost effective and reduced complexity in comparison with other propulsion systems which are currently in use. These improvements are due to the high thermodynamic efficiency obtained because of constant-volume combustion. Pulse detonation cycle can be used for both air-breathing and rocket based systems. Present study investigates the effect of nozzles in various configurations. They are straight nozzle, conical and bell-shaped nozzles with varying length, divergent angles and area ratios on the thrust augmentation of Pulse Detonation Engine (PDE) test rig which was developed by research team at Punjab Engg. College (PEC), Chandigarh. It was found from the experiments that the conical nozzle with high divergent angle of 20° and high nozzle area ratio of around 23 increased the thrust to 14%. The bell shaped nozzle, with 20° angle of divergence and a nozzle area ratio of just around 7, produced 59.5% more thrust in comparison with baseline engine. The augmentation in thrust was found to be as high as 55% in comparison with straight nozzle. Divergent nozzles produced negative thrust with less divergent angle but gave an increment of 11.28% with high angle of divergence in comparison with a straight nozzle.

Improvement and Application of Key Tools for Hydraulic Jet Fracturing

Aiming at the problems of poor reliability, low construction efficiency, and short service life of fracturing string in the application of hydraulic jet technology in Daqing Oilfield, targeted research has been carried out on key tools such as rubber cylinder, slip, and nozzle.A unidirectionally-sealing rubber cylinder adopting composite sealing method was designed. The rubber cylinder could bear the pressure of 80 MPa and temperature resistance of 150∘C under the setting force of 20 kN, with tensile strength increased by 23% and residual deformation rate less than 3%, showing good overall sealing performance and recovery. The finite element method was used to optimize the structural parameters, materials and process of the slip to increase the ability of slips to withstand alternating loads by 1.5 times. The arc-shaped nozzle was improved to reduce the pressure drop and increase the jet density. By improving the performance indicators of key tools, the optimized fracturing string could meet the construction requirements of low setting force, high sealing pressure difference, and repeated setting and fracturing. The improved technical string was applied to section 3459 of well 218 well in the field, with the success rate reaching 100%. The large-scale application of the improved fracturing string satisfied the construction requirements for large-scale volume fracturing of the for the 5 1/2" inch casing new well completion in the low-permeability and tight reservoirs of Daqing Oilfield.

An Improved Reverse Monte Carlo Method for the Investigation of Aerodynamic and Infrared Radiation Characteristics of a Flying Wing UAV

Using the improved ray tracing method to improve the reverse Monte Carlo (RMC) method, which is used to analyze the infrared radiation (IR) characteristics of the exhaust system, can greatly improve the computational efficiency and accuracy, and the calculation accuracy is improved by more than 8% compared with the RMC using ray tracing algorithm. For a flying wing unmanned aerial vehicle (UAV), the influence of the geometry of the double S-shaped nozzles and the single S-shaped nozzles on the internal flow field were analyzed, then the influence of the internal and external flow on the aerodynamic performance of the S-shaped exhaust system, and the IR characteristics of the aircraft with different inlet and exhaust system in the 3μm-5μm and 8μm-14μm bands were studied. The aerodynamic performance of the S-shaped nozzles are studied by numerical simulations. The IR characteristics of the rear hemisphere on the single S-shaped nozzles and the double S-shaped nozzles were obtained, those nozzles have the similar engine matching performance. The double S-shaped nozzle, resulting in a decrease of the radiation intensity of the nozzle by at least 65%, compared to the single S-shaped nozzle in the 3μm-5μm band. The aerodynamic characteristics of the flying wing UAV with the two S-shaped exhaust systems are also compared, and the changes in lift and resistance are analyzed. The forward IR intensity of the flying wing UAV is significantly lower than that of the backward direction, and the upper direction IR intensity is higher than that of the lateral direction and the downward direction. Compared to the flying wing UAV with the single S-shaped exhaust system, the flying wing of the double S-shaped exhaust system has a lower IR intensity, for the peak intensity of the rear hemisphere in the 3μm-5μm band is reduced at least 80%, the maximum value of the locked distance is reduced to 25% of the UAV using the single S curved exhaust system. The ratio of the amount of aircraft skin radiation to the total radiation increases from 30% in the 3μm-5μm band to more than 70% in the 8μm-14μm band. From the results of spectral analysis of UAV from 13μm-14μm, the spectral radiance of the carbon dioxide absorption and emission band in the detector image is significantly less than that of the UAV with a single S-shaped nozzle.

Influence of Nozzle Type, Divergence Angle and Area Ratio on Impulse of Pulse Detonation Engine

The influence of nozzle geometry on the impulse produced by the single cycle Pulse detonation engine (PDE) was experimentally investigated. For each experiment the nozzles were attached at the end of the engine. The impulse produced by the pulse detonation engine was calculated from the measured thrust. The thrust measurement was done by sliding the engine on the central bar of the thrust stand. The main structure of the basic PDE has a detonation tube with one terminal closed, a Schelkin spiral used as deflagration to detonation device, and a thrust stand to support the structure. Stoichiometric acetylene and oxygen mixture were used as detonation mixture. Various nozzles with a range of divergent angle and area ratios were tested. The calculations of the impulse were made from the thrust pulse for the duration it lasted. The effect of the type of nozzle, divergent angle and area ratio were observed. The bell shaped nozzle with large angle of divergence produced maximum specific impulse of 80 Sec with 20° divergence angle and area ratio of 6.942; maximum impulse was produced by the bell shaped nozzle with a small area ratio of 2.969 and 10° divergence angle. The maximum total impulse obtained was 1200 N-sec.

Effect of Hydraulic Diameter on Potential Core Decay of Supersonic Jets

Various studies dealing with decay characteristics of circular and noncircular supersonic jets were conducted by previous researchers. But in these studies due emphasis was not given to the hydraulic diameter (Dh), shape factor (ζ) & the nozzle lip parameters which have significant impact on the characteristics of noncircular supersonic jet. In this study, it has been shown that these parameters played a significant role on supersonic core decay characteristics [2, 3, 6] of the jet. The scope of this study included supersonic core length (Lc), decay pattern, due to noncircular shaped nozzle. In the literature, the supersonic jet characterization and the related experimental correlation are available for optimum expansion conditions whereas for other expansion (under and over) conditions the experimental correlation is barely available. While investigating experimentally, new empirical relations were obtained which were the improved forms of earlier correlations for supersonic core length [4]. For experiments, six different types of nozzles (circular, hexagon, square, triangular, elliptical and rectangular) with the same exit to throat area ratio, convergent length and divergent length were used. The results obtained from the experimentally developed correlations were coherent with numerical results, experimental data and flow visualization.

On-demand sample injection: combining acoustic actuation with a tear-drop shaped nozzle to generate droplets with precise spatial and temporal control

An on-demand droplet injection method for controlled delivery of nanolitre-volume liquid samples to scientific instruments for subsequent analysis is presented.

Parametric Design Method and Performance Analysis of Double S-Shaped Nozzles

A parametric design method, which was based on super-elliptical transition and self-adaption infrared radiation shield for the double S-shaped nozzle, was introduced. The complete shielding of high-temperature components in the S-shaped nozzle was realized. Model experiments and numerical simulations were performed to investigate the effects of offset ratio S/D, the ratio of length to diameter L/D, and the aspect ratio W/H on the aerodynamics and infrared radiation. The results showed that the total pressure recovery and thrust coefficients were improved initially, but dropped rapidly with the increase in offset ratios with the range of investigated parameters. There existed an optimal offset ratio for the aerodynamic performances. Considering the weight penalty, the length of nozzles should only be increased properly to achieve better aerodynamic performances. Both friction and viscous losses caused by large streamwise vortices dominated the aerodynamic performances of nozzles. The nozzle with the aspect ratio of W/H=5.0 was recommended for achieving optimal aerodynamics. The increase in aspect and offset ratios could effectively suppress plume radiation, which was, however, not sensitive to overall radiation. Compared to circular nozzles, double S-shaped nozzles reduced overall infrared radiation by over 50%, which proves significant stealth ability. A balance between aerodynamic performances and infrared radiation suppression could be reached for double S-shaped nozzles.