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The atrial flow regulator is a new self-expandable double-disc fenestrated device providing a calibrated inter-atrial communication. Paediatric reports are scarce. We herein describe a case of complete atrioventricular block complicating the exemption use of an atrial flow regulator in a 5-kg infant with transposition of the great arteries, ventricular septal defect, and right ventricular outflow tract obstruction.

A 6-month-old baby girl, with a history of 2 months of intensive care management and two episodes of cardiac arrest, was transferred from another European country to initiate the “Giessen approach” for end-stage heart failure in children. At the admission, left ventricular ejection fraction was 20%. Severe mitral valve regurgitation and severe left atrial dilatation were present. Right ventricular function was preserved, and tricuspid valve regurgitation was mild. As a result, the patient underwent surgical pulmonary artery banding. Additionally, unloading of the left atrium was achieved by implanting an 8 mm atrial flow regulator device through a hybrid per-atrial approach. Two months after the procedure, the patient was progressively weaned from the inotropes and transferred to the ward.

A high-precision variable-thrust control method based on real-time measurement of pintle displacement and closed-loop feedback control is proposed to solve the technical problems of deep throttling variable-thrust regulation and control of pintle liquid rocket engines (LRE). By optimizing the system structure and control parameters, the closed-loop control of displacement with high precision and a fast response under a wide range of variable thrust can be realized, and thus the large-range, fast-response, and high-precision control of the chamber pressure, equivalent to thrust, can be indirectly realized. The chamber pressure response time is not more than 0.3 s, the overshoot is not more than ±3%, and the pulsation amplitude is not more than ±5%, which can meet the technical requirements of the large-range thrust adjustment and control of variable-thrust LRE of reusable launch rockets. The proposed variable-thrust LRE thrust control system is simple, reliable, and easy to use and maintain, which solves the problem of the large range, high precision, and fast response of thrust adjustment and control. The proposed system can provide important technical support for carrier rocket recycling and launch cost reduction. This is the first time a closed-loop control method of displacement of an integrated gas generator/flow regulator to achieve a 5:1 large-range continuous-variable-thrust control for the LRE of a reusable launch rocket has been proposed.

Passive valves that deliver a constant flow rate regardless of inlet pressure changes have numerous applications in research, industry, and medical fields. The present article describes a passive spring valve that can be adjusted manually to deliver the required flow rate. The valve consists of a movable rod with an engraved microchannel. The fluidic resistance of the device varies together with the inlet pressure to regulate the flow rate. A prototype was made and characterized. Flow-rate adjustment up to +/−30% of the nominal flow rate was shown. A simple numerical model of the fluid flow through the device was made to adapt the design to external ventricular drainage of cerebrospinal fluid (CSF). Some insights about the implementation of this solution are also discussed.

This study investigates the rainfall-runoff process and the pollutant dynamics on theoretical catchments and intermunicipal sewer systems in order to characterize the hydraulic and environmental performance of possible types of sewerage system and to compare the effectiveness of different wet-weather control schemes for intermunicipal sewerage systems. A comprehensive investigation on the placement strategies and the cumulative effects of wet-weather control practices is carried out over a broad watershed as a key preliminary step in addressing surface water safeguard requirements in developing and urban areas. The analysis shows that the different types of intermunicipal sewer system exhibit slightly different performance. Placing wet-weather detention tanks at different spatial levels affects the overall effectiveness of the wet-weather control system. In the examined case study schemes, the insertion of a wet-weather detention tank is better on final than on local flow regulators. The performance control also proves to be easier adopting the solution with intermunicipal tank since, for this scheme, the design criteria have a more important influence than rainfall characteristics on the environmental performance. These results represent an issue of primary focus for the implementation of environmental policies and mitigation strategies against surface water impairment in urban and developing areas.

Transcatheter creation of an interatrial communication using the Occlutech Atrial Flow Regulator Device for pulmonary hypertension or heart failure is well described. We report a case of an 8-year-old boy with a failing Fontan circulation, in whom the Atrial Flow Regulator was used to successfully create a fenestration between the pulmonary artery and left atrium, improving his clinical condition.

Ventilation systems often operate under changing conditions, which leads to a deviation of the actual air flow from the calculated one. When the gravitational pressure increases, they remove more air than the calculated amount, which leads to increased heat expenditure on heating the air, which compensates for exhaust during the cold period of the year. To maintain a constant calculated flow rate and reduce heat losses during the cold season, especially for natural exhaust systems, it is rational to use direct-acting ventilation air flow regulators. The aerodynamic characteristics of such a device for regulating the flow of ventilation air are obtained numerically and experimentally: the coefficient of local resistance ζ and the parameter k, which characterizes the aerodynamic force acting on the movable element of the regulator. The accuracy of experimental study is proved. Comparison of the results of numerical and experimental research showed their good correspondence, which confirms the suitability of the data obtained for the design and calculation of air flow regulators of the considered type.

Hydrodynamic flow regulators are used in environmental engineering as a replacement for traditional flow throttling devices. They are extremely efficient, reliable and free from the common disadvantages of traditional devices. Recent research by the authors indicated that the atomization of a liquid by hydrodynamic flow regulators accelerates oxygenation and may be used for improving the quality of wastewater and stormwater. To date, an evaluation of the aeration capacity of a hydrodynamic flow regulator at the pilot scale or in a practical situation has not been presented in the literature. This study presents the experimental results of oxygen absorption tests for conventional and modified cylindrical hydrodynamic flow regulators (patent pending). These devices were tested in a closed-circuit experimental setup at the semi-commercial scale. The aeration efficiency of hydrodynamic flow regulators was assessed by means of the overall standard oxygen transfer coefficient (KLa(20), h−1) and standard oxygen transfer rate (SOTR, gO2/h) for a wide range of tested configurations. The effect of flow rate and discharge mode on the aeration capacity of flow regulators was investigated. The values of KLa(20) for cylindrical hydrodynamic flow regulators obtained in the experiments were between 2.62 and 15.57 h−1 while SOTR values ranged from 53 to 316 gO2/h. The modified discharge mode with two active outlets allowed for an increase in aeration efficiency of up to 15% compared to conventional designs.

Pipeline-adaptive flow regulator is an important and typical nonlinear system in liquid rocket engines. In this paper, the semi-analytical method of the Time-domain Minimum Residual Method is used. It is applied to obtain the semi-analytical expression of mass flow rate with respect to harmonic waves under sinusoidal pressure disturbance at the system inlet. By comparing the results with numerical integration, the correctness of the Time-domain Minimum Residual Method is verified. Subsequently, this paper discusses the influence of different pipeline lengths on the system massflow rate under given inlet pressure conditions. The results show that within the range of 0.1 to 10.0 meters, the fluctuation of massflow rate is generally small, but at about 4.0 meters, the fluctuation of massflow rate suddenly intensifies significantly. The semi-analytical results of massflow rate show a situation where the coefficients of higher-order harmonics may be larger than those of lower-order harmonics.

Sensory systems encode both the static quality of a stimulus (e.g., color or shape) and its kinetics (e.g., speed and direction). The limits with which stimulus kinetics can be resolved are well understood in vision, audition, and somatosensation. However, the maximum temporal resolution of olfactory systems has not been accurately determined. Here, we probe the limits of temporal resolution in insect olfaction by delivering high frequency odor pulses and measuring sensory responses in the antennae. We show that transduction times and pulse tracking capabilities of olfactory receptor neurons are faster than previously reported. Once an odorant arrives at the boundary layer of the antenna, odor transduction can occur within less than 2 ms and fluctuating odor stimuli can be resolved at frequencies more than 100 Hz. Thus, insect olfactory receptor neurons can track stimuli of very short duration, as occur when their antennae encounter narrow filaments in an odor plume. These results provide a new upper bound to the kinetics of odor tracking in insect olfactory receptor neurons and to the latency of initial transduction events in olfaction. Significance How fast can animals smell? Whereas we know how fast our eyes are (in the cinema, images at 24 Hz fuse for humans, whereas our retina can resolve flickers at more than 100 Hz), olfactory perception is believed to be slow. After all, we take a sniff and later another one. Odor plumes in the air, however, can fluctuate at a millisecond time scale. Here, we show that insect olfactory receptor neurons can have response latencies shorter than 2 ms and resolve odorant fluctuations at more than 100 Hz. This high temporal resolution could facilitate odor-background segregation, and it has important implications for underlying cellular processes (transduction), ecology (odor recognition), and technology (development of fast sensors).