712 research outputs found
Calculated effects of turbine rotor-blade cooling-air flow, altitude, and compressor bleed point on performance of a turbojet engine
Effects of air-cooling turbine rotor blades on performance of a turbojet engine were calculated for a range of altitudes from sea level to 40,000 feet and a range of coolant flows up to 3 percent of compressor air flow, for two conditions of coolant bleed from the compressor. Bleeding at required coolant pressure resulted in a sea-level thrust reduction approximately twice the percentage coolant flow and in an increase in specific fuel consumption approximately equal to percentage coolant flow. For any fixed value of coolant flow ratio the percentage thrust reduction and percentage increase in specific fuel consumption decreased with altitude. Bleeding coolant at the compressor discharge resulted in an additional 1 percent loss in performance at sea level and in smaller increase in loss of performance at higher altitudes
Classification of apple tree disorders using Convolutional Neural Networks.
Abstract?This paper studies the use of Convolutional Neural Networks to automatically detect and classify diseases, nutritional deficiencies and damage by herbicides on apple trees from images of their leaves. This task is fundamental to guarantee a high quality of the resulting yields and is currently largely performed by experts in the field, which can severely limit scale and add to costs. By using a novel data set containing labeled examples consisting of 2539 images from 6 known disorders, we show that trained Convolutional Neural Networks are able to match or outperform experts in this task, achieving a 97.3% accuracy on a hold-out set
Analytical comparison of turbine-blade cooling systems designed for a turbojet engine operating at supersonic speed and high altitude I : liquid-cooling systems
Analytical comparison of turbine-blade cooling systems designed for a turbojet engine operating at supersonic speed and high altitude II : air-cooling systems
Preliminary analysis of effects of air cooling turbine blades on turbojet-engine performance
The effects of turbine-blade cooling on engine performance were analytically investigated for a turbojet engine in which cooling air is bled from the engine compressor. The analysis was made for a constant turbine-inlet temperature and a range of altitudes to determine the minimum cooling requirements to permit substitution of nonstrategic materials in turbine blading. The results indicate that, for a constant inlet temperature, air cooling of the turbine blades increases the specific fuel consumption and decreases the thrust of the engine. The highest possible cooling effectiveness is desirable to minimize coolant weight flow and its effects on engine performance
Online monitoring the isomerization of an azobenzene-based dendritic bolaamphiphile using ion mobility-mass spectrometry
Ion mobility-mass spectrometry was used to obtain detailed information about
the kinetics of the light-induced cis/trans isomerization process of a new
supramolecular azobenzene-based bolaamphiphile. Further experiments revealed
that the investigated light-induced structural transition dramatically
influences the aggregation behaviour of the molecule
Entwicklung und Anwendung molekularer und informatorischer Werkzeuge für das genetische Monitoring bei Wildrüben (Beta sp., Patellifolia sp.)
Entwicklung und Anwendung molekularer und informatorischer Werkzeuge für das genetische Monitoring bei Wildrüben
Development and application of molecular and bioinformatic tools for the genetic monitoring ofwild beets.ZusammenfassungWildlebende Verwandte der Kulturpflanzen (WVK) sind wirtschaftlich wichtige pflanzengenetische Ressourcen (PGR) für die Pflanzenzüchtung. Ein Konzept, solche PGR im natürlichen Habitat (in situ) zu erhalten, ist das genetische Schutzareal. Durch diese Technik ist es möglich, innerartliche Vielfalt zu erhalten und die Entstehung neuer Diversität zu ermöglichen. Das Konzept des genetischen Schutzareals wird an der Gattung Beta im Rahmen des vom Julius Kühn-Institut koordinierten EU-Projekts AEGRO angewendet, erprobt und weiterentwickelt. B. patula (Ait.) (BP) und B. vulgaris (L.) maritima (Arcang.) (BVM) werden dabei als Modellarten genutzt. Beide Spezies sind wichtige PGR für die Zuckerrübenzüchtung. BP ist eine seltene und gefährdete Art mit einem sehr begrenzten Verbreitungsgebiet. Im Gegensatz dazu ist BVM weitverbreitet und kommt u. a. an den Küsten Westeuropas vor. In Folge des globalen Klimawandels wird eine nach Norden gerichtete Migrationsbewegung dieser Unterart erwartet. Basierend auf den durch vorliegende Arbeit geschaffenen Grundlagen soll zu einem späteren Zeitpunkt die Auswirkung dieser Migrationsbewegung auf die genetische Diversität ermittelt werden. Insgesamt wurden 557 Einzelpflanzen von 14 Sammelorten mit jeweils 25 SSR-Markern (Simple Sequence Repeat Marker) untersucht. Zusätzlich wurde eine Datenbank zur Unterstützung des genetischen Monitorings modelliert und implementiert, um die erhobenen Labor- und Felddaten in strukturierter und gut dokumentierter Form für die Auswertung von Zeitserien langfristig in hoher Qualität verfügbar zu halten. Erstmalig wird die geographische Verteilung der genetischen Diversität von BP beschrieben und eine Empfehlung für die Ausweisung eines genetischen Schutzareals für BP gegeben. Auch das Wissen um die geographische Verteilung genetischer Diversität bei BVM wurde weiter vertieft. Stichworte: Wildrüben, SSR-Marker, wildlebende Verwandte der Kulturpflanzen (WVK), genetisches Schutzareal AbstractCrop Wild Relatives (CWR) are an economically important plant genetic resource (PGR) for plant breeding. One strategy to conserve PGR in the natural habitat (in situ) is the genetic reserve technique. This approach protects the existing intraspecific diversity and allows, in contrast to the ex situ approaches, the emergence of new diversity. The genetic reserve conservation technique will be tested in practice with the genus Beta within the framework of the EU project AEGRO. B. patula (Ait.) (BP) and B. vulgaris (L.) maritima (Arcang.) (BVM) are used as models. Both species are important resources for sugarbeet breeding. BP is a rare and endangered species with a very limited habitat. In contrast, BVM is widespread along the shores of Western Europe. This subspecies is expected to migrate in a northward direction as a consequence of the global climate change. The impact of this migration on the genetic diversity will be examined in future analyses and will establish a basis for future research. A total of 557 plants from 14 sampling plots were analysed using 25 SSR markers (Simple Sequence Repeat markers). Additionally, a database was modeled and implemented to support the genetic monitoring by storing and post-processing all laboratory and field data in a well documented and structured way. This makes the data available for the analysis of time series. For the first time the geographic pattern of genetic diversity in the wild beet BP was described and decision criteria for the establishment of a genetic reserve for BP were postulated. The knowledge of geographic patterns of genetic diversity in the wild beet BVM was consolidated as a baseline for further investigations on the potential influence of climate changes and the corresponding geographic range shift on genetic diversity. Keywords: Wild beet, SSR markers, Crop Wild Relatives (CWR), genetic reserve conservationtechniqu
Apple production and quality when cultivated under anti-hail cover in Southern Brazil.
Anti-hail nets may change the microclimate of orchards and hence modify the physicochemical and sensory characteristics of fruits. The present study aimed to evaluate the effects of anti-hail nets on the physical, chemical, and sensory attributes of apples grown in southern Brazil. The study was conducted in commercial orchards, with apples grown under a black anti-hail net under an open sky during the 2008/2009, 2009/2010, and 2010/2011 cycles. Measurements of photosynthetically active radiation were collected at both sites. Physical, chemical, and sensory analyses of fruits were performed in the laboratory. The anti-hail net reduced incident photosynthetically active radiation by 32 %. The light spectrum in the canopy changed the corresponding R/FR (red/far-red) ratio in the lower and upper canopy layers from 0.27 to 1.55, respectively. In contrast to the majority of microclimate studies carried out in the temperate zones of the northern hemisphere, this study in the southern hemisphere showed that although it reduced the incident solar radiation, the cover did not change the color or organoleptic characteristics of ?Royal Gala? and ?Fuji Suprema? apples. The net cover prolonged the subperiod between fruit setting and harvesting, thus slowing fruit ripening. Therefore, the use of anti-hail nets on apple orchards is a suitable alternative for the protection of apple trees against hail because it causes only small changes in the microclimate and in the maturation period, ensuring fruit production without affecting its quality
Predicting temporary threshold shifts in a bottlenose dolphin (Tursiops truncatus) : the effects of noise level and duration
Author Posting. © Acoustical Society of America, 2009. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 125 (2009): 1816-1826, doi:10.1121/1.3068456.Noise levels in the ocean are increasing and are expected to affect marine mammals. To examine the auditory effects of noise on odontocetes, a bottlenose dolphin (Tursiops truncatus) was exposed to octave-band noise (4–8 kHz) of varying durations (<2–30 min) and sound pressures (130–178 dB re 1 µPa). Temporary threshold shift (TTS) occurrence was quantified in an effort to (i) determine the sound exposure levels (SELs) (dB re 1 µPa2 s) that induce TTS and (ii) develop a model to predict TTS onset. Hearing thresholds were measured using auditory evoked potentials. If SEL was kept constant, significant shifts were induced by longer duration exposures but not for shorter exposures. Higher SELs were required to induce shifts in shorter duration exposures. The results did not support an equal-energy model to predict TTS onset. Rather, a logarithmic algorithm, which increased in sound energy as exposure duration decreased, was a better predictor of TTS. Recovery to baseline hearing thresholds was also logarithmic (approximately −1.8 dB/doubling of time) but indicated variability including faster recovery rates after greater shifts and longer recoveries necessary after longer duration exposures. The data reflected the complexity of TTS in mammals that should be taken into account when predicting odontocete TTS.This work was funded by the
Office of Naval Research Grant No. 00014-098-1-687 to
P.E.N. and the support of Bob Gisiner and Mardi Hasting is
noted. Additional support came from SeaSpace to T.A.M
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