Design and evaluation of an integrated Quiet, Clean General Aviation Turbofan (QCGAT) engine and aircraft propulsion system

The design was based on the LTS-101 engine family for the core engine. A high bypass fan design (BPR=9.4) was incorporated to provide reduced fuel consumption for the design mission. All acoustic and pollutant emissions goals were achieved. A discussion of the preliminary design of a business jet suitable for the developed propulsion system is included. It is concluded that large engine technology can be successfully applied to small turbofans, and noise or pollutant levels need not be constraints for the design of future small general aviation turbofan engines

Multi-Impulse to Time Optimal Finite Burn Trajectory Conversion

A novel conversion algorithm is presented that combines the fidelity of indirect optimization methods with the generality of direct methods to more easily solve time-optimal, finite-burn pseudo-rendezvous problems. An algorithm is described that converts a set of multiple-impulses, representing the entirety or a portion of a high- or low-thrust maneuver, to an exact time optimal finite-burn trajectory for a thrust limited, constant exhaust velocity spacecraft. A pseudo-rendezvous problem is one that yields a solution whose final time, position and velocity state is equal to that of the original post-impulsive trajectory. An iterative adjoint-control transformation is used to initialize the optimal control two-point boundary value problem. Examples are shown for both high and low-thrust non-coplanar Earth orbit transfers, as well as a low-thrust Hohmann-type Earth-Mars transfer

Adaption of evolutionary programming to the prediction of solar flares

Adapting evolutionary programming to prediction of solar flare

The Role of Native Language Acquisition in Infant Preferences of Speech and Song

Previous research by Persaud (2013) found that infant listeners preferentially listen longer to sung stimuli over spoken stimuli, regardless of the age of the infant. The present study tests two age groups of infants to determine whether early language exposure affects infants\u27 listening preferences for song and speech. Six- to seven-month- old infants and eight- to ten-month-old infants from English speaking homes were presented with auditory stimuli of English-speaking women speaking or singing and tested in a head-turn preference task. Consistent with the findings from Persaud (2013), it was found that both age groups listened longer to the sung stimuli compared to the spoken stimuli. This suggests that song is inherently more attractive to infants, possibly because song stimuli are generally less acoustically variable compared to speech stimuli, and therefore ultimately easier for infants to cognitively process compared to speech stimuli. The results of this study support a processing-based account of infants\u27 preferences for ID-stimuli

Toward autonomous spacecraft

Ways in which autonomous behavior of spacecraft can be extended to treat situations wherein a closed loop control by a human may not be appropriate or even possible are explored. Predictive models that minimize mean least squared error and arbitrary cost functions are discussed. A methodology for extracting cyclic components for an arbitrary environment with respect to usual and arbitrary criteria is developed. An approach to prediction and control based on evolutionary programming is outlined. A computer program capable of predicting time series is presented. A design of a control system for a robotic dense with partially unknown physical properties is presented

Test Telemetry And Command System (TTACS)

The Jet Propulsion Laboratory has developed a multimission Test Telemetry and Command System (TTACS) which provides a multimission telemetry and command data system in a spacecraft test environment. TTACS reuses, in the spacecraft test environment, components of the same data system used for flight operations; no new software is developed for the spacecraft test environment. Additionally, the TTACS is transportable to any spacecraft test site, including the launch site. The TTACS is currently operational in the Galileo spacecraft testbed; it is also being provided to support the Cassini and Mars Surveyor Program projects. Minimal personnel data system training is required in the transition from pre-launch spacecraft test to post-launch flight operations since test personnel are already familiar with the data system's operation. Additionally, data system components, e.g. data display, can be reused to support spacecraft software development; and the same data system components will again be reused during the spacecraft integration and system test phases. TTACS usage also results in early availability of spacecraft data to data system development and, as a result, early data system development feedback to spacecraft system developers. The TTACS consists of a multimission spacecraft support equipment interface and components of the multimission telemetry and command software adapted for a specific project. The TTACS interfaces to the spacecraft, e.g., Command Data System (CDS), support equipment. The TTACS telemetry interface to the CDS support equipment performs serial (RS-422)-to-ethernet conversion at rates between 1 bps and 1 mbps, telemetry data blocking and header generation, guaranteed data transmission to the telemetry data system, and graphical downlink routing summary and control. The TTACS command interface to the CDS support equipment is nominally a command file transferred in non-real-time via ethernet. The CDS support equipment is responsible for metering the commands to the CDS; additionally for Galileo, TTACS includes a real-time-interface to the CDS support equipment. The TTACS provides the basic functionality of the multimission telemetry and command data system used during flight operations. TTACS telemetry capabilities include frame synchronization, Reed-Solomon decoding, packet extraction and channelization, and data storage/query. Multimission data display capabilities are also available. TTACS command capabilities include command generation verification, and storage

Activation of mating type genes by transposition in Saccharomyces cerevisiae

Yeast Saccharomyces cerevisiae may express an a or alpha mating type. These cells types may be interconverted as a consequence of heritable genetic alteractions at the mating type locus (MAT). According to the more general controlling element model [Oshima, U. & Takano, I. (1971) Genetics 67, 327--335] and the specific cassette model [Hicks, J., Strathern, J. & Herskowitz, I. (1977) in DNA Insertion Elements, Plasmids and Episomes, eds. Bukhari, A. I., Shapiro, J.A. & Adhya, S. L.(Cold Spring Harbor Laboratory, Cold Spring Harbor, NY), pp. 457--462], the regulatory information required for switching the MAT locus exists at two other loosely linked loci, HMa and HMalpha. Specifically, the HMa and HMalpha loci are proposed to carry silent alpha and silent a genes, respectively. According to these models, switching occurs when a replica of a silent gene replaces the resident information at the mating type locus and is thereby expressed. These models predict that mutations at the silent ("storage") loci would generate defective MAT loci subsequent to the switching process. Therefore, the behavior of HMalpha mutants during the mating type interconversion was investigated. The results demonstrate that defective MATa alleles are generated by switching the MATalpha locus in HMalpha mutants. Thus, the genetic information from HMalpha is transposed to the mating type locus. These results provide genetic evidence in support of these models

Human development in the twenty-first century: visionary ideas from systems scientists

Journal ArticleThe dynamic systems approach is an emerging interdisciplinary set of principles used by a diverse collection of scientists to help understand the complex world in which we live. The main insight that unites these scientists, despite wide differences in methods and concepts, is a focus on connections and relationships. A relationship between a particular parent and child, for example, is distinguished by the expressions and gestures as well as the words by which they understand each other. A parent's raised eyebrow might mean "pay attention," or "be careful" to their child. This small and subtle gesture has meaning to both parent and child because they have worked it out together by repeatedly learning how to understand each other, negotiating their mutual needs and goals. The raised eyebrow represents that whole history of the growth of the relationship. The relationship is a dynamic system because it changes over time (it is dynamic) and because the mutually understood gestures are the result of both people working together to create something that is more than either one of them alone (it is a relationship system). A dynamic system is a relationship that grows over time, has a history, and is more than the simple sum of its parts