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This paper presents a performance analysis on a novel engine concept, currently under development, in order to achieve hybrid air-breathing rocket technology. A component-level approach has been developed to simulate the performance of the engine at Mach 5, and the thermodynamic interaction of the different working fluids has been analysed. The bypass ramjet duct has also been included in the model. This facilitates the improved evaluation of performance parameters. The impact of ram drag induced by the intake of the engine has also been demonstrated. The whole model is introduced into a multi-platform application for aeroengine simulation to make it accessible to the interested reader. Results show that the bypass duct modelling increases the overall efficiency by approximately 7%. The model calculates the specific impulse at approximately 1800 seconds, which is 4 times higher than any chemical rocket.

This article examines methodological aspects of the indirect calculation of thrust characteristics of irrotational air-breathing jet engines using telemetry data that can be obtained during high-speed aircraft flight tests. Specific features of determining thrust characteristics during bench and flight tests are described. Mathematical models are developed for data analysis and calculation of the thrust and the specific impulse of an irrotational air-breathing jet engine by internal parameters, as well as its effective thrust in integration with a high-speed aircraft. The proposed approaches are tested, and the developed mathematical models are validated according to the results of experimental bench tests of the thrust characteristics of irrotational air-breathing jet engines in integration with a model fuselage of a high-speed aircraft. Satisfactory convergence of the results of indirect and direct (experimental) force measurements is shown. The data obtained can be used for further development of the method and analysis of bench and flight tests of aircraft with irrotational air-breathing jet engines.

This study was conducted to determine the sub-lethal toxicity of Captan® on selected hematological (Hb, HCT, MCH) growth (K-factor, HSI, SGR), biochemical (serum glucose, protein), and endocrine parameters (growth hormone, T3 and T4) in Clarias batrachus under chronic exposures. Captan® was administered at predetermined exposure concentrations (0.53 and 1.06 mg/L) and monitored at day 15, 30 and 45 of the experimental periods. The experimental groups showed significantly lower values (p 3 and T4) emerged as the most sensitive biomarker category, depicting modulated responses between sub-chronic exposure at day-15 and chronic responses at day-45. In general, the study findings using these biomarkers indicate that Captan® exposures are capable of inducing stress-specific effects at the biochemical and physiological levels negatively impacting the overall health and longevity of such animals. The use of the IBR index provided a visual and easily comprehensible depiction of toxicity effects and biomarker responses in laboratory exposed fish and we anticipate a greater applicability in biomarker data from the wild which are largely heterogenous.

Modern liquid-fuel rocket propulsion harbors a number of great limitations. Among those is the weight of fuel, which makes up more than 90% of the mass of the SpaceX Falcon 9 (NASA, 2018). Electric propulsion has been used for decades as an alternative to liquid-fuel rockets due to low propellant requirements and high specific impulse. Although electric thrusters have strictly been used in non-atmospheric conditions, recent innovations attempt to expand its use to airspace. This quasi-experimental study focuses on the creation of an air-breathing magnetoplasmadynamic (MPD) thruster, with attempts being made to maximize the efficiency of the engine. Immense safety concerns prevented testing from occurring after the engine was built. However, the estimated performance of the built MPD is compared to a multitude of existing forms of electric propulsion, from Hall-effect thrusters to electrodynamic tethers. The concluding evidence suggests that air-breathing MPDs are not currently viable, high-power photon thrusters being of greater use in atmospheric conditions. Further research focusing on decreasing atmospheric breakdown voltage and increasing mirror reflectance of photon thrusters is suggested.

Air breathing rocket engines require turbomachinery and ducting that is substantially lighter than that used in ground based or aerospace gas turbines. In order to reduce the weight of the axial compressor, the design of the inter-spool swan neck duct is targeted. In this paper a circumferential splitter blade is used to reduce loading and diffusion on the duct endwalls. The splitter and duct geometry are coupled and optimised together using 2D CFD. A design is selected that is 30% shorter than ducts that are currently used in aerospace gas turbines and the 3D flow features are investigated in further detail using an experimental rig and 3D CFD. This paper shows that the “splittered” duct has 3 benefits over a conventional duct design: First, separation of the endwalls is prevented even at short duct lengths, this will reduce distortion into the downstream compressor. Second, losses generated by corner separations on structural struts can be reduced by 20%, enabling short ducts to achieve high performance. Third, splittered ducts are shown to be twice as robust to uncertain inlet flow conditions as conventional ducts. This allows a designer to target high performance short designs with reduced risk.

Shi et al. recently identified a brainstem peptidergic circuit in mice that is activated at birth and stabilizes breathing during the transition from the intra-utero environment to air breathing. This network remains important for maintaining stable breathing and respiratory homeostasis throughout development, and deficiencies in this network may be linked to sudden infant death syndrome (SIDS).

This scheme makes the best use of structure of the cargo ship by integrating with air-breathing helicon plasma electrical propulsion. The normal operation of a manned space station requires regular replenishment of oxygen, fuel, food and instruments. Research on resupply spacecraft to supply oxygen and fuel to the space station will help reduce the replenishment needs of the station. A resupply spacecraft with air-breathing electrical propulsion as core technology will meet the replenishment needs of the space station during on-orbit operation at a low cost and bring high loading capacity and substantial economic benefits. The replenishment ship based on this scheme can collect 1000 kg working gas a year on 180 km orbit and reduce the cost of building and launching cargo ships. This paper carried out studies on mission process, resource consumption, orbit design and thrust Analysis. The ionization mode of air-breathing electrical propulsion is helicon discharge and the average power for orbit maintaining and air collecting is about 775 W.

Lithium-oxygen (Li-O2) batteries have been intensively investigated in recent decades for their utilization in electric vehicles. The intrinsic challenges arising from O2 (electro)chemistry have been mitigated by developing various types of catalysts, porous electrode materials, and stable electrolyte solutions. At the next stage, we face the need to reform batteries by substituting pure O2 gas with air from Earth's atmosphere. Thus, the key emerging challenges of Li-air batteries, which are related to the selective filtration of O2 gas from air and the suppression of undesired reactions with other constituents in air, such as N2, water vapor (H2O), and carbon dioxide (CO2), should be properly addressed. In this review, we discuss all key aspects for developing Li-air batteries that are optimized for operating in ambient air and highlight the crucial considerations and perspectives for future air-breathing batteries.

It is expected that aquaculture alone will provide around two third of global fish consumption by 2030, as catches from wild capture fisheries has been either decreasing or stagnant. Majority of the air breathing fish species have very high consumer preference as food fish for their unique taste, nutritional and therapeutic value. Although these species are often considered as weed and unwanted fish in aquaculture, yet they play an important role in supplementing the nutritional requirement of resource poor fishers and farmers and providing livelihood through ornamental fish trade for entrepreneurs. However, not much scientific information is available on the nutritional requirement and food habit of the air breathing fish species. A change or transformation of feeding habit of several air breathing fish species with the advances of their life stages have been reported.

Six-degree-of-freedom measurements have been performed with an aerodynamic model of a small-scale hypersonic air-breathing vehicle. The model was tested in two test campaigns in two different wind ...

Aim: Decannulation of tracheostomy in cases of traumatic quadriplegia is always a challenge due to respiratory muscle paralysis, chest infections, aspiration and need to care for sacral sores. Aim of this study was to identify and overcome the difficulties in decannulation of tracheostomy in cases of quadriplegia due to cervical spinal cord injury. Material and methods: This prospective observational study was carried out in a tertiary care Spinal Cord Injury Center of a Military Hospital. Ten cases of tracheostomized traumatic quadriplegics were evaluated over 3years. Decannulation was considered once there was normal gag reflex, effective cough, manageable aspiration, oxygen saturation above 90%, no serious pulmonary compromise and no need for bed sores surgery. The cases were followed up for further one year post-decannulation. Results: Eight cases could be decannulated successfully. Only two cases could not be decannulated due to feeble chest movement, ineffective Cough, lack of motivation and occasional aspiration. Conclusion: Cervical cord injury patients have difficult decannulation due to weak respiratory muscles, ineffective cough, aspiration, pulmonary pathology and bed sores. Respiratory muscle exercise, quantified peak cough pressure, assisted coughing, risk benefit approach in aspiration, healing of bed sores and team work are keys to successful decannulation

The dramatic transition to air breathing at birth represents a true challenge for the newborn infant mammal, a period in which neonatal respiratory diseases are common. Since the 1930s, fetal and newborn lambs have been the model of choice for whole-animal studies on neonatal respiration. The present review aims to illustrate the relevance of ovine models in studying the establishment of successful breathing at birth and its maintenance in the early postnatal period, as well as a number of abnormal conditions that can interfere with these processes.

The six-degree-of-freedom (six-DOF) modeling of air-breathing hypersonic vehicles (AHVs) is highly complex due to the variable flight conditions, structural elasticity and inherent aero-propulsive coupling. However, considering different modeling approaches, a significant amount of work has been reported in the area of AHV modeling. The aim of this paper is to investigate the six-DOF modeling of AHVs reported in the literature. Next, owing to the modeling uncertainties and coupled dynamics, state-of-the-art robust adaptive control design techniques have been presented for these models, which are also briefly reviewed in this paper. This survey also contains a small discussion on possible future advancements in the modeling and control of these vehicles.

Problems on designing the air-breathing ramjet electric propulsion thruster for controlling loworbit spacecraft motion are examined in the paper. Information for choosing orbits’ altitudes for reasonable application of an air-breathing ramjet electric propulsion thruster and propellant exhaust velocity is presented. Estimates of the probable increase of gas concentration in the area of air-breathing ramjet ionization are presented. The test results of the thruster are also given.

This study develops a novel back-stepping controller with prescribed performance for air-breathing hypersonic vehicles (AHVs) utilizing non-affine models. For the velocity dynamics, a non-affine control law is addressed to achieve prescribed tracking performance. The altitude subsystem is rewritten as a strict feedback formulation to facilitate the back-stepping control system design via a model transformation approach. At each step of back-stepping design, performance functions are constructed to force tracking errors to fall within prescribed boundaries, based on which desired transient performance and steady-state performance are guaranteed for both velocity and altitude control subsystems. Furthermore, the exploited controllers are accurate model independent, which guarantees control laws with satisfactory robustness against unknown uncertainties. Meanwhile, the proposed control scheme can cope with unknown control gains. By the Lyapunov stability theory, the stability of the closed-loop control system is confirmed. Finally, numerical simulations are given for an AHV to validate the effectiveness of the proposed control approach.

Although most fishes extract oxygen from the water, a small number of species rely on air-breathing to meet some or all of their oxygen requirements. These species, almost exclusively found in tropical freshwater systems, are of major importance to human nutrition, particularly in South East Asia, where more than 90% of the global production resides, largely in delta areas. Air-breathing fishes are capable of growing in deeply hypoxic water as is the case with the most produced Pangasiid catfishes, and many species are capable of very high growth rates. Here, we briefly present the current culture types and associated water quality. We discuss how the ability to breathe in both air and water dramatically influences their tolerance to the variables used to monitor and control water quality in water-breathing fish aquaculture, and how improvements in water quality might increase productivity in the culture of air-breathing fishes.

Recently there has been a resurgence of interest in achieving practical hypersonic flight especially since China and Russia has announced successful demonstration of their military technology. The key enabler for hypersonic is the scramjet engine as the air breathing propulsion device. Engineering design of a scramjet intake is crucial since unwanted shock-shock interactions inside the intake could impede safe combustion process. In this study, we demonstrate that minimal geometry modification of the intake could significantly increase its performance. A generic scramjet intake that performs sub optimally is shown to benefit greatly by having its cowl deflected inwards at small degree. Pressure-sensitive paint measurement showed that peak pressure due to adverse shock-shock interactions at cowl tip has been reduced significantly.

This paper designs a finite-time output tracking controller for air-breathing hypersonic vehicles (AHVs) subjected to disturbances and actuator constraints. After proper derivations, the original model is divided into two independent subsystems undergoing mismatched lumped disturbance. A finite-time disturbance observer (FTDO) is employed to estimate the lumped disturbance, while an auxiliary system combined with a command pre-filter is designed to analyze the effect of input saturation caused by the restrained actuators. Based on the FTDO and the auxiliary system, a novel integral sliding surface is constructed and then a chattering-free nonsingular controller is developed to realize finite-time output tracking in spite of mismatched lumped disturbance and input saturation, which is its major merit compared with other existing AHV controllers. A simulation study is carried out to verify the proposed control scheme.

Globally, many researchers have been trying to improve the fuel economy of a vehicle for satisfying future CO 2 regulation and minimizing air pollution problem. For the same background, diesel engine and vehicle system optimization using simulation models have been key technologies for the improvement of vehicle system efficiency. Therefore, in this study, calibration method for the air breathing system of a WGT diesel engine using mean value model has been composed for efficient engine and vehicle optimization simulation researches. And virtual WGT performances have been calculated for a 2 cylinder downsized diesel engine system. From these researches, the calibration method for the boost pressure and EGR rate of a virtual diesel engine related with WGT performances could be composed and some of technical issue related with downsized diesel engine could be investigated. Key words :WGT(웨이스트게이트형 터보과급기), Diesel engine( 디젤엔진), Engine calibration( 엔진보정), Mean value model(평균값모델), EGR(배기가스재순환)

In this paper, a combination of feedback linearization and disturbance observer-based control (DOBC) is adopted for the design of a state-feedback controller that regulates the velocity and altitude of air-breathing hypersonic vehicles (AHVs) subject to constrained inputs. First, a disturbance observer is established to estimate the overall effect of possible uncertainties and disturbances on the nominal vehicle model which is called the lumped disturbance. Then, a compensation method is proposed based on disturbance observer and feedback linearization control to counteract the mismatched lumped disturbance. Furthermore, a novel antiwindup modification is implemented on the baseline control to handle the possible input saturation. The designed controller addresses the issue of stability robustness with respect to system uncertainties and disturbances, and achieves zero-error tracking with good performance and antiwindup property meanwhile, which is the major merit compared with other existing AHV controllers. Finally, simulation is presented to verify the effectiveness of this control scheme.

New European Resuscitation Council (ERC) and UK guidelines for ‘Resuscitation and support of transition of babies at birth’ were published simultaneously in October 2015.1 Both are based on the evidence derived from a critical evaluation of relevant scientific publications over the preceding 5 years organised and coordinated by the International Liaison Committee on Resuscitation (ILCOR).2 ,3 Where there was no new evidence the guidelines may reflect those evidence evaluations carried out in 20054 or 20105 and incorporate published papers not evaluated by the ILCOR. This article summarises both the process and the main areas of change (box 1), which, for the most part, are refinements of previous guidelines. It will also briefly discuss ongoing areas of controversy where evidence was insufficient to lead to inclusion. Box 1 ### Main areas of change in the 2015 European Resuscitation Council and UK newborn resuscitation guidelines The title of the guidelines has been changed from Resuscitation at Birth to Resuscitation and support of transition at birth to reflect an emphasis on supporting transition to air breathing rather than resuscitation. A delay in the clamping of the cord of at least 1 min from the time of complete delivery of the baby is recommended for all babies when possible. The newborn baby's temperature should be maintained in the normal range (36.5°C to 37.5°C) unless it is being considered for therapeutic hypothermia. Active steps should be taken to achieve this. An accurate assessment of heart rate can be made using ECG or pulse oximetry. Tracheal intubation and suction is no longer routine for any baby born through meconium-stained liquor. Instead the emphasis should be on providing appropriate resuscitative manoeuvres as soon as possible and only intubate the trachea for suction in those infants whose airway is blocked. Begin the resuscitation of term babies …

Aim: We describe the technique of septoplasty and turbinectomy/turbinoplasty performed concomitantly with orthognathic surgery, via the Le Fort I, after the push down of the maxilla. Objective: To describe the technique of septoplasty and turbinectomy concomitant with Le Fort I type osteotomy, through the same pathway, after the push down of the maxilla. Method: Literature review and description of surgical technique.

The shock-induced combustion ramjet engine is the most favorable air breathing propulsive system and a suitable option for high-speed flight. In this paper, theoretical analysis and numerical simulations were conducted to study the thrust performance of shock-induced combustion ramjet engines. Firstly, the propulsive performance of supersonic combustion ramjet engines was theoretically analyzed by using the Chapman-Jouguet detonation theory. Then, the aerodynamic principles of shock-induced combustion ramjet engines were put forth on the basis of the theoretical analysis results. Finally, a full-scale shock-induced combustion ramjet engine was designed according to the aerodynamic principles. Two-dimensional numerical simulations were conducted to simulate its combustion flow field and propulsive performance. The numerical results demonstrate the correctness and application of the theoretical aerodynamic principles.

Jet engines require special materials that can withstand the demanding environments imposed on the various components and sections, so selection of materials is primary requirement during design of jet engine components. This paper is the study of various materials and their applicability for different components of jet engine for the purpose of enhancing the performance, reliability and durability. Review of materials for different types of jet engines such as turbojet engine, turboprop engine, turbofan engine, turboshaft engine, ramjet and scramjet engine is presented. This paper overviews the properties and materials used for different types of jet engines and can be used for further researchers in the field of jet engine materials.

Motivational interviewing amp shared decision making a primer for audiologists working in a world with more than one right choice