Computational simulation for concurrent engineering of aerospace propulsion systems

Results are summarized for an investigation to assess the infrastructure available and the technology readiness in order to develop computational simulation methods/software for concurrent engineering. These results demonstrate that development of computational simulation methods for concurrent engineering is timely. Extensive infrastructure, in terms of multi-discipline simulation, component-specific simulation, system simulators, fabrication process simulation, and simulation of uncertainties--fundamental to develop such methods, is available. An approach is recommended which can be used to develop computational simulation methods for concurrent engineering of propulsion systems and systems in general. Benefits and issues needing early attention in the development are outlined

High Temperature Composite Analyzer (HITCAN) demonstration manual, version 1.0

This manual comprises a variety of demonstration cases for the HITCAN (HIgh Temperature Composite ANalyzer) code. HITCAN is a general purpose computer program for predicting nonlinear global structural and local stress-strain response of arbitrarily oriented, multilayered high temperature metal matrix composite structures. HITCAN is written in FORTRAN 77 computer language and has been configured and executed on the NASA Lewis Research Center CRAY XMP and YMP computers. Detailed description of all program variables and terms used in this manual may be found in the User's Manual. The demonstration includes various cases to illustrate the features and analysis capabilities of the HITCAN computer code. These cases include: (1) static analysis, (2) nonlinear quasi-static (incremental) analysis, (3) modal analysis, (4) buckling analysis, (5) fiber degradation effects, (6) fabrication-induced stresses for a variety of structures; namely, beam, plate, ring, shell, and built-up structures. A brief discussion of each demonstration case with the associated input data file is provided. Sample results taken from the actual computer output are also included

Biosinteza, fermentacija, purifikacija i primjena surfaktina

Surfactin, a bacterial cyclic lipopeptide, is produced by various strains of Bacillus subtilis and is primarily recognized as one of the most effective biosurfactants. It has the ability to reduce surface tension of water from 72 to 27 mN/m at a concentration as low as 0.005 %. The structure of surfactin consists of seven amino acids bonded to the carboxyl and hydroxyl groups of a 14-carbon fatty acid. Surfactin possesses a number of biological activities such as the ability to lyse erythrocytes, inhibit clot formation, lyse bacterial spheroplasts and protoplasts, and inhibit cyclic 3\u27,5-monophosphate diesterase. The high cost of production and low yields have limited its use in various commercial applications. Both submerged and solid-state fermentation have been investigated with the mutational approach to improve the productivity. In this review, current state of knowledge on biosynthesis of surfactin, its fermentative production, purification, analytical methods and biomedical applications is presented.Surfaktin, ciklički lipopeptid izoliran iz različitih sojeva bakterije Bacillus subtilis, jedan je od najučinkovitijih biosurfaktanata, koji čak i u koncentraciji od 0,005 % smanjuje površinsku napetost vode sa 72 na 27 mN/m. Sastoji se od 7 aminokiselina vezanih karboksilnim i hidroksilnim skupinama na masnu kiselinu sa 14 ugljikovih atoma. Biološka je aktivnost surfaktina raznovrsna: razgrađuje eritrocite, sprečava zgrušavanje, razgrađuje bakterijske sferoplaste i protoplaste te inhibira 3\u27,5-fosfodiesterazu. Veliki troškovi proizvodnje i mali prinosi ograničavaju njegovu komercijalnu uporabu, pa je ispitana mogućnost povećanja proizvodnje surfaktina uzgojem mutanata Bacillus subtilis u tekućoj i na čvrstoj podlozi. U ovom su revijalnom prikazu opisana najnovija dostignuća u biosintezi, fermentaciji, purifikaciji, analizi i biomedicinskoj primjeni surfaktina

Another method to maintain positive-pressure ventilation through the Montgomery® T tube

We describe airway management in a patient who had a Montgomery® T tube in situ. The main concern pertaining to these patients is the inadequate depth of anaesthesia and ventilation, in view of loss of volume of air and gases, as well as dilution through the proximal end of the Montgomery®  T tube. To circumvent these problems, we describe another method of providing ventilation, through the extraluminal horizontal limb of the Montgomery®  T tube by introducing an uncuffed endotracheal tube and minimising the loss of carrier gases to the larynx, together with a review of literature for the same.Keywords: Montgomery® T tube, positive-pressure ventilationSouth Afr J Anaesth Analg 2013;19(5):274-27

Biosinteza, fermentacija, purifikacija i primjena surfaktina

Surfactin, a bacterial cyclic lipopeptide, is produced by various strains of Bacillus subtilis and is primarily recognized as one of the most effective biosurfactants. It has the ability to reduce surface tension of water from 72 to 27 mN/m at a concentration as low as 0.005 %. The structure of surfactin consists of seven amino acids bonded to the carboxyl and hydroxyl groups of a 14-carbon fatty acid. Surfactin possesses a number of biological activities such as the ability to lyse erythrocytes, inhibit clot formation, lyse bacterial spheroplasts and protoplasts, and inhibit cyclic 3\u27,5-monophosphate diesterase. The high cost of production and low yields have limited its use in various commercial applications. Both submerged and solid-state fermentation have been investigated with the mutational approach to improve the productivity. In this review, current state of knowledge on biosynthesis of surfactin, its fermentative production, purification, analytical methods and biomedical applications is presented.Surfaktin, ciklički lipopeptid izoliran iz različitih sojeva bakterije Bacillus subtilis, jedan je od najučinkovitijih biosurfaktanata, koji čak i u koncentraciji od 0,005 % smanjuje površinsku napetost vode sa 72 na 27 mN/m. Sastoji se od 7 aminokiselina vezanih karboksilnim i hidroksilnim skupinama na masnu kiselinu sa 14 ugljikovih atoma. Biološka je aktivnost surfaktina raznovrsna: razgrađuje eritrocite, sprečava zgrušavanje, razgrađuje bakterijske sferoplaste i protoplaste te inhibira 3\u27,5-fosfodiesterazu. Veliki troškovi proizvodnje i mali prinosi ograničavaju njegovu komercijalnu uporabu, pa je ispitana mogućnost povećanja proizvodnje surfaktina uzgojem mutanata Bacillus subtilis u tekućoj i na čvrstoj podlozi. U ovom su revijalnom prikazu opisana najnovija dostignuća u biosintezi, fermentaciji, purifikaciji, analizi i biomedicinskoj primjeni surfaktina

An observational study to determine accuracy of various methods used to assign gestational age and correlate with outcome

Background: Appropriate estimation of gestational age is paramount in obstetric care. Uncertain gestational age may lead to adverse pregnancy outcome like low birth weight, spontaneous or iatrogenic preterm delivery and perinatal mortality independent of maternal characteristics. In India, seeking of early medical attention in pregnancy is still not the norm. Three methods to estimate the estimated date of delivery are available, namely, menstrual history, clinical examination and by ultrasound.  This study attempts to analyse the accuracy of the three methods used and their correlation with maternal and fetal outcome.Methods: 260 patients presenting to the outpatient department were enrolled irrespective of the gestational age but as soon as they got registered. Ultrasonography was advised if the patient did not have one. EDD was calculated by various methods and was recorded. If significant discrepancy existed, EDD was reassigned. Patients were followed up till the time of their delivery. After the delivery of the baby gestational age was assessed by the neonatologist and was compared with the gestational age at the time of delivery by the three methods. Maternal and fetal outcomes were compared in the form of avoided inductions and maturity of the baby at the time of delivery by all the three methods.Results: The kappa coefficient for the agreement between dating by ultrasound scan and neonatologist was 0.415 whereas for menstrual dates and clinical examination it was 0.197 and 0.369 respectively thus it can be interpreted that the accuracy of ultrasonography may be slightly better than menstrual dates and clinical examination. 75 patients required reassigning of EDD, Induction of labor for supposed post-term pregnancy was avoided in 13% of the patients.Conclusions: Ultrasonography was found to be accurate for determination of term /preterm/ post-term births followed by clinical examination and then the menstrual EDD. Induction of labor for supposed post-term pregnancy was avoided in 13% of the patients in whom EDD was ”assigned” thus stressing that EDD should be reassigned when there is discrepancy between menstrual EDD, Ultrasonography EDD and EDD by clinical examination

High temperature composite analyzer (HITCAN) user's manual, version 1.0

This manual describes 'how-to-use' the computer code, HITCAN (HIgh Temperature Composite ANalyzer). HITCAN is a general purpose computer program for predicting nonlinear global structural and local stress-strain response of arbitrarily oriented, multilayered high temperature metal matrix composite structures. This code combines composite mechanics and laminate theory with an internal data base for material properties of the constituents (matrix, fiber and interphase). The thermo-mechanical properties of the constituents are considered to be nonlinearly dependent on several parameters including temperature, stress and stress rate. The computation procedure for the analysis of the composite structures uses the finite element method. HITCAN is written in FORTRAN 77 computer language and at present has been configured and executed on the NASA Lewis Research Center CRAY XMP and YMP computers. This manual describes HlTCAN's capabilities and limitations followed by input/execution/output descriptions and example problems. The input is described in detail including (1) geometry modeling, (2) types of finite elements, (3) types of analysis, (4) material data, (5) types of loading, (6) boundary conditions, (7) output control, (8) program options, and (9) data bank

A new data analysis framework for the search of continuous gravitational wave signals

Continuous gravitational wave signals, like those expected by asymmetric spinning neutron stars, are among the most promising targets for LIGO and Virgo detectors. The development of fast and robust data analysis methods is crucial to increase the chances of a detection. We have developed a new and flexible general data analysis framework for the search of this kind of signals, which allows to reduce the computational cost of the analysis by about two orders of magnitude with respect to current procedures. This can correspond, at fixed computing cost, to a sensitivity gain of up to 10%-20%, depending on the search parameter space. Some possible applications are discussed, with a particular focus on a directed search for sources in the Galactic center. Validation through the injection of artificial signals in the data of Advanced LIGO first observational science run is also shown.Comment: 21 pages, 8 figure

Influence of Bulk Fluid Velocity on the Efficiency of Electrohydrodynamic Pumping

The efficiency of conversion of electrical power into fluidic power in an electrohydrodynamic (EHD) pump depends on the bulk fluid velocity. An analytical formulation is developed for calculation of the efficiency of an EHD pump, with and without the presence of a superimposed flow due to an externally imposed pressure gradient. This formulation is implemented into a numerical model, which is used to investigate the effect of bulk fluid velocity on the efficiency of the EHD action. In particular, the net flow due to the combined action of EHD and a positive or negative external pressure gradient is computed. Both ion-drag pumps and induction EHD pumps are considered. Pumps based on the ion-drag principle that are studied include a one-dimensional pump, a twodimensional pump driven by a stationary potential gradient, and another driven by a traveling potential wave. Two-dimensional repulsion-type and attraction-type induction pumping caused by a gradual variation in the electrical conductivity of the fluid is also investigated. The efficiency of EHD pumps exhibited a strong dependence on bulk fluid velocity: for the two-dimensional steady ion-drag pump, for example, the efficiency increased from less than 2% to 22% under the influence of an external pressure gradient. The corresponding increase in efficiency for a two-dimensional repulsion-type EHD pump was from 0.26% to 24.5%

An improved algorithm for narrow-band searches of continuous gravitational waves

Continuous gravitational waves signals, emitted by asymmetric spinning neutron stars, are among the main targets of current detectors like Advanced LIGO and Virgo. In the case of sources, like pulsars, which rotational parameters are measured through electromagnetic observations, typical searches assume that the gravitational wave frequency is at a given known fixed ratio with respect to the star rotational frequency. For instance, for a neutron star rotating around one of its principal axis of inertia the gravitational signal frequency would be exactly two times the rotational frequency of the star. It is possible, however, that this assumption is wrong. This is why search algorithms able to take into account a possible small mismatch between the gravitational waves frequency and the frequency inferred from electromagnetic observations have been developed. In this paper we present an improved pipeline to perform such narrow-band searches for continuous gravitational waves from neutron stars, about three orders of magnitude faster than previous implementations. The algorithm that we have developed is based on the {\it 5-vectors} framework and is able to perform a fully coherent search over a frequency band of width $\mathcal{O}$(Hertz) and for hundreds of spin-down values running a few hours on a standard workstation. This new algorithm opens the possibility of long coherence time searches for objects which rotational parameters are highly uncertain.Comment: 19 pages, 8 figures, 6 tables, submitted to CQ