167 research outputs found
Turbofan engine model for estimation of the fuel consumption for compensation of auxiliary energy supply
Побудовано математичну модель, яка враховує вплив відібраної від турбовентиляторного двигуна пневматичної потужності та потужності на валу генератора на витрати пального. Модель дає добрі результати в усьому літальному діапазоні й на всіх основних режимах двигуна. Реалізація виконана як підпрограма в програмному середовищі Matlab і призначена для доповнення вже існуючої моделі двигуна. Вона являє собою детерміновану чисельну модель ідентифікації. Дані для неї генеровані чисельними експериментами в софтверному продукті Gasturb. Перевірку моделі виконано шляхом порівняння результатів повної моделі польоту літака, в якій інтегровані розглядувана модель двигуна з даними з літальної документації та літальних записів.The presented model is suited for estimation of the influence on fuel consumption of the pneumatic and generator shaft power will be off-take from turbofan engine. It is made to be applicable for the entire aircraft flight envelope and engine operating modes. The model is realized in Matlab environment and is intended to complement the performance model of the engine, that is already developed [2]. The model is based mainly on polynomial interpolation. The data, used for the synthesis of the model is generated by simulation with Gasturb software. The model is validated by comparison with data published in the relevant Aircraft Flight manual and flight data records
Numerical modelling of turbofan engine deterioration as a factor in the airlines fuel conservation
The boosting of the fuel efficiency of in-service aircraft is an issue of great commercial and ecological importance. One of the ways to achieve this is by adjusting the flight parameters and flight planning to the particular performance level of every single airplane. Main contributors to the aircraft performance deterioration are the aerodynamic and power plant deterioration. In this paper a mathematical modelling approach for the estimation of the effect of turbofan engine deterioration on passenger aircraft performance is proposed. Based on previous flight models developed by the authors, the present model simulates the deterioration of CFM-56-like turbofans on an Airbus A319-like airplane, and makes possible to compare the performance of airplanes with deteriorated and not deteriorated engines over various flight missions. A representative scenario is explored as an illustration. The model can be further developed to include the aerodynamic deterioration of the aircraft as well as other operational factors.
First published online 29 January 202
Investigation of superfast deposition of metal oxide and Diamond-Like Carbon thin films by nanosecond Ytterbium (Yb+) fiber laser
Metal oxide (MOx, M: titanium, magnesium) and Diamond-Like Carbon (DLC) thin films were synthesized by Pulsed Laser Deposition (PLD) at room temperature and low vacuum of 2 Pa for MOx and vacuum of 4 x 10(-3) Pa for DLC films. A fiber based Ytterbium (Yb+) laser operating in the nanosecond regime at a repetition rate of 20 kHz was used as an ablation source. Dense and smooth thin films with a thickness from 120 to 360 nm and an area of up to 10 cm(2) were deposited on glass and stainless steel substrates at high growth rates up to 2 nm/s for a laser intensity of 10-12 J/cm(2). The thin films synthesis was compared for two fiber laser modes of operation, at a repetition rate of 20 kHz and with an additional modulation at 1 kHz. The morphology, chemical composition and structure of the obtained thin films were evaluated using optical microscopy, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX) and Raman spectroscopy. The morphology of the MOx thin films and the deposition rate strongly depend on the fiber laser mode of operation. Very smooth surfaces were obtained for the metal oxide thin films deposited at lower deposition rates in the modulation mode at 1 kHz. The effect of the substrate on the DLC film structure was studied. The films deposited on dielectric substrates were identified as typical tetrahedral (ta-C) DLC with high sp(3) content. DLC films on metal substrates were found typical a-C amorphous carbon films with mixing sp(2)/sp(3) bonds
A first course in feedback, dynamics and control: findings from an online pilot survey for the IFAC community
Undergraduate students in many engineering programs around the world take only one control course. The IFAC Educational Committee has developed and piloted to a limited audience a comprehensive survey for the topics to be included in such course. This issue is relevant to both academia and industry. The paper discusses the initial findings related to the design of the survey as well as the responses of the participants. The findings will be used to refine the survey and distribute it in the near future to the global control community
Susceptibility to Neurodegenerative Disorders: Insights from Paleogenomic Data
Ancient human genome data that has accumulated in recent years can be employed to establish the spatiotemporal trajectories of genetic variants associated with human diseases. Such knowledge might illuminate if and how past adaptations impact contemporary human health and medicine. Scarcely any studies have yet been attempted to evaluate the genetic susceptibility to neurodegenerative disorders in ancient human communities. Using publicly available ancient human genome-wide data the present study evaluates the molecular predisposition to neurodegenerative disorders in ancient human communities. To this end we screened the ancient genome-wide data for the presence of variants unequivocally associated with neurodegenerative disorders in modern populations, and their historical and geographic prevalence was assessed. These variants are two rare variants in the LRRK2 gene associated with Mendelian Parkinson\u27s disease, a pathogenic variant in the CRH gene, associated with autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE), and a rare variant in the TREM2 gene, a possible risk modifier associated with Alzheimer\u27s disease. Our assessment of the historical and geographic prevalence indicates differing spatiotemporal frequency dynamics for these clinically significant variants. Neurodegenerative disorders are often with poorly understood pathogenesis that might be elucidated by studying the interaction of past genetic variability with ecological and evolutionary factors such as adverse environmental conditions, specific selective pressures, periods of population isolation and admixture processes. Data on molecular predisposition to neurodegenerative disorders in ancient genomes is instructive to modern medical diagnostic and therapeutic practices
Life history and demographic determinants of effective/census size ratios as exemplified by brown trout (Salmo trutta)
A number of demographic factors, many of which related to human-driven encroachments, are predicted to decrease the effective population size (Ne) relative to the census population size (N), but these have been little investigated. Yet, it is necessary to know which factors most strongly impact Ne, and how to mitigate these effects through sound management actions. In this study, we use parentage analysis of a stream-living brown trout (Salmo trutta) population to quantify the effect of between-individual variance in reproductive success on the effective number of breeders (Nb) relative to the census number of breeders (Ni). Comprehensive estimates of the Nb/N ratio were reduced to 0.16–0.28, almost entirely due to larger than binomial variance in family size. We used computer simulations, based on empirical estimates of age-specific survival and fecundity rates, to assess the effect of repeat spawning (iteroparity) on Ne and found that the variance in lifetime reproductive success was substantially higher for repeat spawners. Random family-specific survival, on the other hand, acts to buffer these effects. We discuss the implications of these findings for the management of small populations, where maintaining high and stable levels of Ne is crucial to extenuate inbreeding and protect genetic variability.publishedVersio
Technical committee on control education
Presents information of the CS society Presents information of the CS society Technical Committee on Control Education
Q fever in Bulgaria and Slovakia.
As a result of dramatic political and economic changes in the beginning of the 1990s, Q-fever epidemiology in Bulgaria has changed. The number of goats almost tripled; contact between goat owners (and their families) and goats, as well as goats and other animals, increased; consumption of raw goat milk and its products increased; and goats replaced cattle and sheep as the main source of human Coxiella burnetii infections. Hundreds of overt, serologically confirmed human cases of acute Q fever have occurred. Chronic forms of Q fever manifesting as endocarditis were also observed. In contrast, in Slovakia, Q fever does not pose a serious public health problem, and the chronic form of infection has not been found either in follow-ups of a Q-fever epidemic connected with goats imported from Bulgaria and other previous Q-fever outbreaks or in a serologic survey. Serologic diagnosis as well as control and prevention of Q fever are discussed
A survey of international views on a first course in systems and control for engineering undergraduates
This paper summarises the results of an international survey of academics and industrialists on what should be prioritised in the first, and often only, control course taken by engineering undergraduates. The results are made up both of quantitative data whereby respondents selected from a number of options, and also of qualitative data where respondents entered free comments. Reflections on the results and summaries of common trends are given to help readers consider how the curriculum in their own institutions might be updated and modified to meet modern requirements. At the time of writing the survey had around 500 respondents covering a good spread of nationalities, employment status and engineering disciplines
On an IFAC online pilot survey for a first course on control
The paper introduces aims and objectives of the IFAC survey for a first course on control and discusses some its basic features
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