Thrust stand evaluation of engine performance improvement algorithms in an F-15 airplane

An investigation is underway to determine the benefits of a new propulsion system optimization algorithm in an F-15 airplane. The performance seeking control (PSC) algorithm optimizes the quasi-steady-state performance of an F100 derivative turbofan engine for several modes of operation. The PSC algorithm uses an onboard software engine model that calculates thrust, stall margin, and other unmeasured variables for use in the optimization. As part of the PSC test program, the F-15 aircraft was operated on a horizontal thrust stand. Thrust was measured with highly accurate load cells. The measured thrust was compared to onboard model estimates and to results from posttest performance programs. Thrust changes using the various PSC modes were recorded. Those results were compared to benefits using the less complex highly integrated digital electronic control (HIDEC) algorithm. The PSC maximum thrust mode increased intermediate power thrust by 10 percent. The PSC engine model did very well at estimating measured thrust and closely followed the transients during optimization. Quantitative results from the evaluation of the algorithms and performance calculation models are included with emphasis on measured thrust results. The report presents a description of the PSC system and a discussion of factors affecting the accuracy of the thrust stand load measurements

Measurement effects on the calculation of in-flight thrust for an F404 turbofan engine

A study was performed that investigates parameter measurement effects on calculated in-flight thrust for the General Electric F404-GE-400 afterburning turbofan engine which powered the X-29A forward-swept wing research aircraft. Net-thrust uncertainty and influence coefficients were calculated and are presented. Six flight conditions were analyzed at five engine power settings each. Results were obtained using the mass flow-temperature and area-pressure thrust calculation methods, both based on the commonly used gas generator technique. Thrust uncertainty was determined using a common procedure based on the use of measurement uncertainty and influence coefficients. The effects of data nonlinearity on the uncertainty calculation procedure were studied and results are presented. The advantages and disadvantages of using this particular uncertainty procedure are discussed. A brief description of the thrust-calculation technique along with the uncertainty calculation procedure is included

LANGUAGE DOCUMENTATION ON JAVANESE: A SHIFT TOWARDS RECOGNIZING AND CELEBRATING COLLOQUIAL VARIETIES

Javanese has benefitted from a long history of linguistic study. To focus on grammars, Javanese boasts grammars in French by Favre (1866); in Dutch by Kiliaan (1919), Prijohoetomo (1937), Arps et al. (2000); in Indonesian by Suharno (1982), Sudaryanto (1991; ed), Wedhawati et al. (2006); in English by Horne (1961), Keeler (1992), Robson (2014); among others. Although Javanese already has a stable scholarly tradition, the focus has been almost exclusively on the Standard variety, spoken in the principalities of Yogyakarta and Solo, constituting a small sliver of the attested language. Given its vast dialectal variation, there is still a huge need for linguistic research on Javanese. With the advent of establishing language documentation as a branch of linguistics (Himmelmann 1991), some progress has been made in the documentation and description of colloquial varieties: for example, Suwadji (1981) on Javanese varieties on the north coast of Central Java; Conners (2008) on Tengger Javanese; Hoogervorst (2010) on Surabayan Javanese; Vander Klok (2012) on Paciran Javanese. These works represent a shift towards the recognition and validation of non-standard varieties of Javanese, which were unnoticed in the past. We advocate for the continuation of this trend. In particular, we present our work on the documentation of two colloquial varieties of Javanese, Malang Javanese and Semarang Javanese, for which the outcome of this project is a reference grammar. We end by highlighting the importance of such documentation, especially of non-standard varieties, for language maintenance: even large languages are susceptible to language endangerment, and Javanese is no exception (e.g. Kurniasih 2006; Smith-Hefner 2009; Cohn et al. 2013)

Effects of commercial fishing on local abundance of Pacific cod (Gadus macrocephalus) in the Bering Sea

Groundfish fisheries in the southeast Bering Sea in Alaska have been constrained in recent years by management measures to protect the endangered Steller sea lion (Eumetopias jubatus). There is concern that the present commercial harvest may produce a localized depletion of groundfish that would affect the foraging success of Steller sea lions or other predators. A three-year field experiment was conducted to determine whether an intensive trawl fishery in the southeast Bering Sea created a localized depletion in the abundance of Pacific cod (Gadus macrocephalus). This experiment produced strongly negative results; no difference was found in the rate of seasonal change in Pacific cod abundance between stations within a regulatory no-trawl zone and stations in an immediately adjacent trawled area. Corollary studies showed that Pacific cod in the study area were highly mobile and indicated that the geographic scale of Pacific cod movement was larger than the spatial scale used as the basis for current no-trawl zones. The idea of localized depletion is strongly dependent on assumed spatial and temporal scales and contains an implicit assumption that there is a closed local population. The scale of movement of target organisms is critical in determining regional effects of fishery removals

Innovations in practice: an objective measure of attention, impulsivity and activity reduces time to confirm attention deficit/hyperactivity disorder diagnosis in children: a completed audit cycle

Background Diagnosing attention deficit/hyperactivity disorder (ADHD) in children and young people typically relies on clinical observation and subjective parent, teacher and self-reports. The subjective nature of reports combined with contradictory or missing data can result in diagnostic uncertainty and delay. The aim of this study was to assess whether the addition of an objective test of attention, impulsivity and activity (QbTest) as an adjunct to standard ADHD assessment could accelerate the diagnostic process in routine National Health Service (NHS) settings. Method In a pre vs. post-test audit design, case records were examined in 40 cases diagnosed without the QbTest [pre-QbTest group] and 40 cases diagnosed with the QbTest [QbTest group], recording the number of consultations until a confirmed ADHD diagnosis was reached. Results Using Poisson regression, significantly fewer clinician consultations (mean 2.18 vs. 3.05; p < .02) were required to confirm the diagnosis of ADHD when the QbTest was used to augment assessment in comparison to standard assessment as usual. Conclusions The findings suggest that the addition of the QbTest to standard clinical assessment may reduce time to diagnosis and potentially result in cost savings to the NHS. These preliminary data suggest that there is a potentially clinically meaningful benefit of adding the QbTest to routine clinical ADHD assessment and this should be examined next in the context of a randomised controlled trial

Flight evaluation of an extended engine life mode on an F-15 airplane

An integrated flight and propulsion control system designed to reduce the rate of engine deterioration was developed and evaluated in flight on the NASA Dryden F-15 research aircraft. The extended engine life mode increases engine pressure ratio while reducing engine airflow to lower the turbine temperature at constant thrust. The engine pressure ratio uptrim is modulated in real time based on airplane maneuver requirements, flight conditions, and engine information. The extended engine life mode logic performed well, significantly reducing turbine operating temperature. Reductions in fan turbine inlet temperature of up to 80 F were obtained at intermediate power and up to 170 F at maximum augmented power with no appreciable loss in thrust. A secondary benefit was the considerable reduction in thrust-specific fuel consumption. The success of the extended engine life mode is one example of the advantages gained from integrating aircraft flight and propulsion control systems

First Steps in Identifying Wood

Wood samples need to be identified for all sorts of reasons, and they come in all shapes, sizes and conditions. I’ve received samples that were sound, samples that were waterlogged, samples that were rotted or otherwise degraded, painted samples, furniture samples, even samples containing wood preservatives. Most of the samples I receive have a North American origin, but I also receive pieces from art museums and antique dealers that can originate from just about anywhere. This sometimes means that identifying the sample by a common name alone doesn’t provide enough information

Of Traction and Syndicates: How Great Men and Greed Built Los Angeles at 600 Volts

The Pacific Electric Railroad was once the most extensive electric Interurban globally with 1,100 miles of electrified track over four counties; now, all that remains is 88 miles of light-rail track in Los Angeles. Why was the P.E. important to our local history, and who even cares about some old trains? This paper intends to link the development of Greater Los Angeles with the Pacific Electric and its predecessor companies. Great men who have left their lasting mark like Henry Huntington, Edward Harriman, Isais Hellman, and General Moses Sherman did so by using a combination of land speculation, utility development, and privately owned transit companies to lure millions of migrants to Southern California