Aeroacoustics of supersonic jet flows from contoured and solid/porous conical plug-nozzles

The results of an experimental study of the acoustic far-field, the shock associated noise, and the nature of the repetitive shock structure of supersonic jet flows issuing from plug-nozzles having externally-expanded plugs with pointed termination operated at a range of supercritical pressure ratios Xi approaching 2 to 4.5 are reported. The plug of one of these plug-nozzles was contoured. The other plug-nozzles had short conical plugs with either a solid surface or a combination of solid/porous surface of different porosities. The contoured and the uncontoured plug-nozzles had the same throat area and the same annulus-radius ratio K = R sub p/R sub N = 0.43. As the result of modifications of the shock structure, the acoustic performance of improperly expanded jet flows of an externally-expanded short uncontoured plug of an appropriate geometry with suitably perforated plug and a pointed termination, is shown to approach the acoustic performance of a shock-free supersonic jet issuing from an equivalent externally-expanded contoured plug-nozzle

Alteration in 5HT1A Receptor Activity from a Prenatal Exposure to Dexamethasone in a Stressed and Non-Stressed Adult Male Rat

Synthetic glucocorticoids (GC) are used as a clinical therapeutic to stimulate lung development in fetuses that present the risk of preterm delivery. Previous studies have shown that a prenatal exposure to Dexamethasone (DEX) causes a disturbance in normal GC mediation of neuritic outgrowth, cell signaling, and serotonergic systems. Our hypothesis is that a prenatal exposure to DEX during the third trimester of pregnancy alters 5HT1A receptor function. Pregnant dams were injected daily with 150μg/ml/kg of DEX from gestation day 14 through 19. Control dams were treated with and equal volume of saline. Swim stress followed by elevated plus maze testing was conducted on male rats an hour and a half prior to being sacrificed to induce postnatal acute stress. The non-stressed group was also tested and allowed to return to baseline before sacrifice. Hippocampi were analyzed using a radioligand-receptor binding assay and GTPγS35 incorporation (3H-MPPF antagonist and 8-OH-DPAT agonist, respectively). A significant increase in Kd was found in non-stressed DEX-exposed animals compared to non-stressed controls (

Conceptual modeling of knowledge based systems for digital ecosystems

The agents or entities frequently require intelligence in the form of knowledge based systems(KBS) to support many of their functions. In this Paper we discuss how these KBSs are conceptual are conceptually modeled as a first step towards their development. In particular, we show to effectively model all the different knowledge constructs using an extended definition of an object. The notation used to express this is UML [Booch 2005]

DYNASTAT: A Methodology for Dynamic and Static Modeling of Multi-agent Systems

Multi-agent systems are increasingly being used within various knowledge domains. The need for modeling of the multi-agent systems in a systematic and effective way is becoming more evident. In this chapter, we present the DYNASTAT methodology. This methodology involves a conceptual overview of multi-agent systems, a selection of specific agent characteristics to model, and a discussion of what has to be modeled for each of these agent characteristics. DYNASTAT is independent of any particular modeling language but provides a framework that can be used to realize a particular language in the context of a real-world example. UML 2.2 was chosen as the modeling language to implement the DYNASTAT methodology and this was illustrated using examples from the medical domain. Several UML 2.2 diagrams were selected including a use case, composite structure, sequence and activity diagram to model a multi-agent system able to assist botha medical researcher and a primary care physician. UML 2.2 provides a framework for effective modeling of agent-based systems in a standardized way which this chapter endeavors to demonstrate