Performance-limit criteria for the design of fast-response servo-actuation systems

Analysis of a typical nonlinear electrohydraulic servo-model establishes the dynamic-performance capabilities of servo-actuation systems

Investigation on the Biocontrol of Phytophthora diseases on strawberry based on antagonism

After screening of several rhizosphere bacteria against the soilborne pathogens of red core and crown rot disease of strawberry Phytophthora fragariae var. fragariae and Phytophthora cactorum under in vitro conditions, three of the most active isolates which produced up to 63% of reduction in mycelium growth, such as Raoultella terrigena (G-584), Bacillus amyloliquefaciens (G-V1) and Pseudomonas fluorescens (2R1-7) were selected for further studies under in vivo conditions. In a greenhouse and field experiments, mentioned above three isolates were tested against both Phytophthora diseases under artificial infested soil conditions. Root dip treatment with these bacterial antagonists produced a control effect on both fungal diseases between 27 to 55 % and were in some cases comparable with the chemical fungicide Aliette

Propulsion control and control theory: A new research focus

Technological developments necessary for the implementation of advanced digital control concepts for aircraft propulsion are identified and discussed. Developments associated with the replacement analog controllers with digital control systems, sensors and actuators, and control modes and software are reported

The Role of Modern Control Theory in the Design of Controls for Aircraft Turbine Engines

Accomplishments in applying Modern Control Theory to the design of controls for advanced aircraft turbine engines were reviewed. The results of successful research programs are discussed. Ongoing programs as well as planned or recommended future thrusts are also discussed

Dynamic performance analysis of a fuel-control valve for use in airbreathing engine research

Dynamic performance analysis of fast-response fuel control valve for air breathing engine researc

A digital computer propulsion control facility: Description of capabilities and summary of experimental program results

Flight weight digital computers are being used today to carry out many of the propulsion system control functions previously delegated exclusively to hydromechanical controllers. An operational digital computer facility for propulsion control mode studies has been used successfully in several experimental programs. This paper describes the system and some of the results concerned with engine control, inlet control, and inlet engine integrated control. Analytical designs for the digital propulsion control modes include both classical and modern/optimal techniques

Can a 3+2 Oscillation Model Explain the NuTeV Electroweak Results?

The weak mixing angle result from NuTeV falls three standard deviations above the value determined by global electroweak fits. It has been suggested that one possible explanation for this result could be the oscillation of electron neutrinos in the NuTeV beam to sterile neutrinos. This article examines several cases of masses and mixings for 3+2 neutrino oscillation models which fit the current oscillation data at 99% CL. We conclude that electron to sterile neutrino oscillations can account for only up to a third of a standard deviation between the NuTeV determination of the weak mixing angle and the standard model.Comment: 3 pages, 2 figures, submitted to Brief Report

Derived subjects in Kinyarwanda locative constructions

No Abstract

Impact of shear rate and reverse flow on cardiac morphogenesis and gene expression in the embryonic zebrafish heart, The

Includes bibliographical references.2015 Fall.Missteps in formation of the embryonic heart can have drastic consequences, making cardiac malformations a common human birth defect. During development, biomechanical factors including shear stress and reverse flow impact cardiogenesis. Shear stress is an epigenetic biomechanical force acting upon endothelial cells. Normally, a short period of reverse flow occurs prior to atrioventricular valve formation during ventricle systole and atrial diastole. The goal of our research is to investigate how altered biomechanical forces acting on endocardial cells lead to genetic responses by the heart. The mammalian zinc finger transcription factor Krüppel-like factor 2 (KLF2) responds to shear stress signals. Here, we explore the zebrafish KLF genes: klf2a, klf2b, and klf4. Whole embryo RT-PCR indicates that the three genes are expressed throughout early development, with cardiac expression in all genes present by 48 hours post fertilization. To evaluate how changes in biomechanical environments trigger altered gene expression in endocardial cells, we used comparative qPCR to quantify klf2a, klf2b, and klf4 expression levels in embryonic hearts with altered shear stress or reverse flow. Knockdown of the hematopoiesis gene gata2 was found to decrease blood viscosity, thereby decreasing both shear stress and reverse flow. Knockdown of contractility gene filaminCb was found to decrease shear stress but significantly increase reverse flow. Using high-speed imaging we quantified these forces and correlated changes in klf2a, klf2b, and klf4 expression. klf2a expression levels decreased in response to changes in both blood viscosity and cardiac contractility. klf2b and klf4 expression levels did not significantly change with these changes in biomechanical stresses. Our investigations considered the impact of blood viscosity versus cardiac contractility on KLF expression and determined that klf2a is a flow response gene. This data confirms previous studies that klf2a is in fact a flow response gene and shows that klf2b and klf4 are not responsive to changes in blood viscosity or cardiac contractility. Future studies will use transcriptomic approaches to identify genes regulated by the KLF family in response to shear stress and reverse flow cues