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Auswahl der wissenschaftlichen Literatur zum Thema „Air shower technique“
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Zeitschriftenartikel zum Thema "Air shower technique"
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Sanyal, S., B. Ghosh, SK Sarkar, A. Bhadra, A. Mukherjee und N. Chaudhuri. „An Analysis of Cosmic Ray Air Showers for the Determination of Shower Age“. Australian Journal of Physics 46, Nr. 4 (1993): 589. http://dx.doi.org/10.1071/ph930589.
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A sample of 8651 air showers in the size range 104 . 3_106 . 2 has been analysed to determine the distribution of the measured age in terms of (i) the number of showers in a specified size range, and (ii) the radial distances in individual showers. It is shown that the radial age distribution in an individual shower leads to an average shower age approximately the same as the prediction of the electron-photon cascade theory. The other results include a study of the variation of (i) shower age, as measured by the x2-minimisation technique, with shower size of vertically incident showers, and (ii) the measured electron density at any point with its radial distance from the shower axis, as a function of the age of a large shower group with very small spread in size. A comparison of similar measurements with relevant theory is also included.
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Schröder, Frank G. „Air Shower Detection by Arrays of Radio Antennas“. EPJ Web of Conferences 208 (2019): 15001. http://dx.doi.org/10.1051/epjconf/201920815001.
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Antenna arrays are beginning to make important contributions to high energy astroparticle physics supported by recent progress in the radio technique for air showers. This article provides an update to my more extensive review published in Prog. Part. Nucl. Phys. 93 (2017) 1. It focuses on current and planned radio arrays for atmospheric particle cascades, and briefly references to a number of evolving prototype experiments in other media, such as ice. While becoming a standard technique for cosmic-ray nuclei today, in future radio detection may drive the field for all type of primary messengers at PeV and EeV energies, including photons and neutrinos. In cosmic-ray physics accuracy becomes increasingly important in addition to high statistics. Various antenna arrays have demonstrated that they can compete in accuracy for the arrival direction, energy and position of the shower maximum with traditional techniques. The combination of antennas and particles detectors in one array is a straightforward way to push the total accuracy for high-energy cosmic rays for low additional cost. In particular the combination of radio and muon detectors will not only enhance the accuracy for the cosmic-ray mass composition, but also increase the gamma-hadron separation and facilitate the search for PeV and EeV photons. Finally, the radio technique can be scaled to large areas providing the huge apertures needed for ultra-high-energy neutrino astronomy.
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Meyhandan, R., und R. W. Clay. „Improving the Angular Resolution of the Buckland Park Air Shower Array“. Publications of the Astronomical Society of Australia 9, Nr. 1 (1991): 113–14. http://dx.doi.org/10.1017/s1323358000025121.
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AbstractAir showers initiated by primary cosmic rays and gamma rays produce shower fronts which are curved. However, the arrival directions of air shower events have normally been fitted assuming a planar shower front. We present a technique which takes the average shower front shape into account to assign an improved shower direction after a first analysis assuming a plane front. We then examine the resulting angular resolution of the Buckland Park array.
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HUEGE, TIM, und HEINO FALCKE. „SIMULATIONS OF RADIO EMISSION FROM COSMIC RAY AIR SHOWERS“. International Journal of Modern Physics A 20, Nr. 29 (20.11.2005): 6831–33. http://dx.doi.org/10.1142/s0217751x05030223.
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Radio emission from cosmic ray air showers has the potential to become an additional, cost-effective observing technique for cosmic ray research, being largely complementary to the well-established particle detector and air fluorescence techniques. We present Monte Carlo simulations of radio emission from extensive air showers in the scheme of coherent geosynchrotron radiation from electron-positron pairs gyrating in the earth's magnetic field. Preliminary results of our simulations are the predicted frequency, primary particle energy, shower zenith angle, shower azimuth angle and polarization dependence of the radio emission. These properties can be directly related to data measured by LOPES and other experiments.
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Schlüter, F., und T. Huege. „Expected performance of air-shower measurements with the radio-interferometric technique“. Journal of Instrumentation 16, Nr. 07 (01.07.2021): P07048. http://dx.doi.org/10.1088/1748-0221/16/07/p07048.
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Cronin, J. W. „Gamma-ray astronomy by the air shower technique: Performance and perspectives“. Il Nuovo Cimento C 19, Nr. 6 (November 1996): 847–63. http://dx.doi.org/10.1007/bf02508125.
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Leach, S. A., und J. S. Lapington. „Extensive air shower tracker using Cherenkov detection“. Journal of Instrumentation 17, Nr. 09 (01.09.2022): C09008. http://dx.doi.org/10.1088/1748-0221/17/09/c09008.
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Abstract Cosmic rays continuously bombard Earth’s atmosphere triggering cascades of secondary particles. Many constituents progress to reach the surface and capturing these events can intrigue and awe young curious minds, opening them to the amazing world of physics. Cloud chambers are an established method of revealing the subatomic world; frequently used by universities to introduce cosmic rays to visitors and prospective students, they provide a fascinating real-time display of the ‘ghostly’ particles showering upon those viewing. Using the Cherenkov radiation detection technique, we have developed a novel, compact, Extensive Air Shower (EAS) particle tracking method that enhances the cloud chamber visualisation of cosmic ray interactions towards a digital audience. Once digital, live event interaction can be streamed to multiple display devices presenting an immediate illustration of the event that showered in that location. Our instrument hardware is built around Cherenkov-optimised silicon photomultiplier sensors. Each single detection unit monitors particle event rate and tracks incident angle by measuring Cherenkov intensity. By operating multiple detection units in one location, we can record time correlated air shower events to monitor and collate information on the primary cosmic rays. We introduce first results, illustrating instrument response and EAS rate variations, compiled from the initial running period of our development instruments. We present intensity spectra, compare with simulation, and describe the instrument response due to sensor location, Cherenkov intensity, mean muon energy and detector acceptance angle. With further development towards low-cost readout electronics, we aim to build a networked array of trackers, located around the campus, to expand data gathering ability and scientific potential.
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Zilles, Anne, Olivier Martineau-Huynh, Kumiko Kotera, Matias Tueros, Krijn de Vries, Washington Carvalho und Valentin Niess. „Radio Morphing - towards a fast computation of the radio signal from air-showers“. EPJ Web of Conferences 216 (2019): 03012. http://dx.doi.org/10.1051/epjconf/201921603012.
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Over the last decades, radio detection of air showers has been established as a promising detection technique for ultrahigh-energy cosmic rays and neutrinos. Very large or dense antenna arrays are necessary to be proficient at collecting information about these particles and understanding their properties accurately. The exploitation of such arrays requires to run massive air-shower simulations to evaluate the radio signal at each antenna position, taking into account features such as the ground topology. In order to reduce computational costs, we have developed a fast computation of the emitted radio signal on the basis of generic shower simulations, called Radio Morphing. The method consists in the calculation of the radio signal of any air-shower by i) a scaling of the electric-field amplitude of a reference air shower to the target shower, ii) an isometry on the simulated positions and iii) an interpolation of the radio pulse at the desired position. This technique enables one to gain many orders of magnitude in CPU time compared to a standard computation. In this contribution, we present this novel tool and explain its methodology. In particular, Radio Morphing will be a key element for the simulation chain of the Giant Radio Array for Neutrino Detection (GRAND) project, that aims at detecting ultra-high-energy neutrinos with an array of 200 000 radio antennas in mountainous regions.
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Sokolsky, P., und R. D’Avignon. „The Unreasonable Effectiveness of the Air-Fluorescence Technique in Determining the EAS Shower Maximum“. Journal of Experimental and Theoretical Physics 134, Nr. 4 (April 2022): 459–68. http://dx.doi.org/10.1134/s1063776122040100.
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Cao, Zhen. „EAS Arrays at High Altitudes Start the Era of UHE γ-ray Astronomy“. Universe 7, Nr. 9 (09.09.2021): 339. http://dx.doi.org/10.3390/universe7090339.
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The evolution of extensive air shower detection as a technique for γ-ray astronomical instrumentation for the last three decades is reviewed. The first discoveries of galactic PeVatrons by the Large High Altitude Air Shower Observatory demonstrate the importance of this technique in ultra-high energy γ-ray astronomy. Utilizing this technique, the origins of high energy cosmic rays may be discovered in the near future.
Dissertationen zum Thema "Air shower technique"
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Sanyal, Subrata. „A Study of sensitivity of different high energy interaction models by the cosmic ray extensive air shower technique at the energy levels of 10^14 eV“. Thesis, University of North Bengal, 1995. http://hdl.handle.net/123456789/678.
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Nolan, Sam Joffre. „Simulation studies of the imaging atmospheric Cherenkov technique using the Durham Mark 6 and H.E.S.S. stand-alone telescopes“. Thesis, Durham University, 2002. http://etheses.dur.ac.uk/4193/.
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The subject of this thesis is the simulation study of the development of extensive air show ers produced by very high energy gamma-ray and hadronic cosmic rays with respect to the Cherenkov light they produce, and its imaging in ground based telescopes. Chapters 1-4 are introductory: Chapter 1 covers the mechanisms responsible for the production of very high energy gamma-rays, whereas, chapter 2 focusses on the development of extensive air showers and Cherenkov light production. Chapter 3 covers the instrumentation used to measure the Cherenkov light using the imaging atmospheric Cherenkov technique. Chapter 4 covers known and possible sources of very high energy gamma-rays. Chapters 5, 6 and 7 cover research performed by the author: Chapter 5 discusses some of the differences between three popular extensive air shower simulations codes, namely ALTAI, CORSIKA and MOCCA. Chapter 6 details the simulation of the response of two ground based imaging atmospheric Cherenkov telescope (the Durham Mark 6 and stand-alone H.E.S.S. telescopes), and in particular details the derivation of the flux of the x-ray selected BL-LAC PKS 2155-304 with the Durham Mark 6 telescope. This represents the refinement of a published measurement given an improved telescope simulation. The significance of the signal seen is 6.8o, and the integral flux derived above 1.5 TeV (assuming a differential spectral slope of-2.6) is {2.5±0.7stat ± (^0.5)(_1.6syst) x 10(^-7) photons m(^-2) s(^-1) Chapter 7 discusses the importance of the atmosphere, and the results of shower simulations under different atmospheric assumptions are presented, which indicate the importance of atmospheric calibration for the new generation of Cherenkov telescopes. The results of this chapter suggest that to first order large changes in the low level aerosol concentration have a much more significant effect on the trigger rate of a stand-alone H.E.S.S. telescope, than on the Hillas parameter distributions seen. Chapter 8 brings together the work done in this thesis, and highlights a final set of fluxes for the active galactic nuclei sources seen with the Durham Mark 6 telescope, many of which will form future sources to be measured with the H.E.S.S. system. The current status of the stand-alone H.E.S.S. system is also covered in chapter 8. The thesis concludes with a further brief discussion of the future prospects for imaging atmospheric Cherenkov astronomy.
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Jahn, Anton [Verfasser], Christian [Akademischer Betreuer] Stegmann und Christian [Gutachter] Stegmann. „Development and Quantification of an advanced Gamma-Ray Reconstruction Technique for the Cherenkov Telescope Array based on a semi-analytical Model for Extended Air Showers / Anton Jahn ; Gutachter: Christian Stegmann ; Betreuer: Christian Stegmann“. Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2019. http://d-nb.info/1201551587/34.
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Juryšek, Jakub. „Pozorování zdrojů gama záření a kalibrace observatoře Cherenkov Telescope Array“. Doctoral thesis, 2020. http://www.nusl.cz/ntk/nusl-437552.
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In this thesis, we present the Monte Carlo study of two prototypes of tele- scopes for the Cherenkov Telescope Array (CTA) observatory, followed by the first data analysis partially using our reconstruction pipeline based on Random Forests. The Monte Carlo model of the SST-1M prototype is created and val- idated by comparison with data. Using the precise Monte Carlo models, we evaluate the performance of the SST-1M and LST-1 prototypes, working so-far in mono-regime as standalone telescopes, resulting in their energy and angular resolution, and the differential sensitivity. We also present an analysis of the data from the first two Crab Nebula observation campaigns conducted with the LST-1 telescope. In the last part of the thesis, we present a study of aerosol optical depth of the atmosphere above both future sites of the CTA observa- tory, retrieved from photometric measurements of Sun/Moon photometers. We focus on the photometer in-situ calibration for nocturnal measurements and introduce corrections to minimize systematic shifts between diurnal and noc- turnal measurements. Using the developed methods, we present the aerosol characterization of both CTA sites based on the photometric data. 1
Bücher zum Thema "Air shower technique"
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Dang, Pragya, und Constance D. Lehman. Breast MRI Overview: Imaging Techniques and Equipment, Clinical Uses, Image Interpretation. Herausgegeben von Christoph I. Lee, Constance D. Lehman und Lawrence W. Bassett. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780190270261.003.0009.
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Contrast-enhanced breast MRI is a highly sensitive modality for early detection and diagnosis of breast cancer, particularly in high-risk populations. It has also been shown to be superior to mammography in establishing the extent of disease in patients with newly diagnosed breast cancer. This chapter, appearing in the section on breast cancer overview, reviews breast MRI imaging technique, clinical uses, gives an overview of image interpretation, and applied physics. Topics discussed include equipment such as hardware, imaging protocols, patient preparation and positioning, and relevant physics. Additionally, clinical situations where the use of breast MRI is appropriate, systematic review of images, and formulation of final assessment and recommendations in accordance with the ACR BI-RADS imaging lexicon are discussed in this chapter.
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Halper, Donna L. Icons of Talk. www.greenwood.com, 2008. http://dx.doi.org/10.5040/9798400668036.
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Americans love talk shows. In a typical week, more than 13 million Americans listen to Rush Limbaugh, whose syndicated radio show is carried by about 600 stations. On television, Oprah Winfrey's syndicated talk show is seen by an estimated 30 million viewers each week. Talk show hosts like Winfrey and Limbaugh have become iconic figures, frequently quoted and capable of inspiring intense opinions. What they say on the air is discussed around the water cooler at work, or commented about on blogs and fan web sites. Talk show hosts have helped to make or break political candidates, and their larger-than-life personalities have earned them millions of fans (as well as more than a few enemies). Icons of Talk highlights the most groundbreaking exemplars of the talk show genre, a genre that has had a profound influence on American life for over 70 years. Among the featured: • Joe Pyne • Jerry Williams • Herb Jepko • Randi Rhodes • Rush Limbaugh • Larry King • Dr. Laura Schlesinger • Steve Allen • Jerry Springer • Howard Stern. • Oprah Winfrey • Don Francisco • Cristina Saralegui • Tavis Smiley • James Dobson • Don Imus Going behind the scenes, this volume showcases the techniques hosts used to motivate (and sometimes aggravate) audiences, and examines the talk show in all of its various formats, including sports-talk, religious-talk, political-talk, and celebrity-talk. Each entry places the talk format and its hosts into historical context, addressing such questions as: What was going on in society when these talkers were on the air? How did each of them affect or change society? What were the issues they liked to talk about and what reaction did they get from listeners and from critics? How were talk hosts able to persuade people to vote for particular candidates or support certain policies? Which hosts were considered controversial and why? Complete with photographs, a timeline, and a resource guide of sources and organizations, this volume is ideal for students of journalism and media studies.
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Endicott, Timothy. Administrative Law. Oxford University Press, 2018. http://dx.doi.org/10.1093/he/9780198804734.001.0001.
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Administrative Law explains the constitutional principles of the subject. It brings clarity to this complex field of public law. The common law courts, government agencies, and Parliament have developed a wide variety of techniques for controlling the enormously diverse activities of twenty-first-century government. Underlying all that variety is a set of constitutional principles. This book uses the law of judicial review to identify and to explain these principles, and then shows how they ought to be worked out in the private law of tort and contract, in the tribunals system, and in non-judicial techniques such as investigations by ombudsmen, auditors, and other government agencies. The aim is to equip the reader to take a principled approach to the controversial problems of administrative law.
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Scott-Smith, Tom. On an Empty Stomach. Cornell University Press, 2020. http://dx.doi.org/10.7591/cornell/9781501748653.001.0001.
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This book examines the practical techniques humanitarians have used to manage and measure starvation, from Victorian “scientific” soup kitchens to space-age, high-protein foods. Tracing the evolution of these techniques since the start of the nineteenth century, the book argues that humanitarianism is not a simple story of progress and improvement, but rather is profoundly shaped by sociopolitical conditions. Aid is often presented as an apolitical and technical project, but the way humanitarians conceive and tackle human needs has always been deeply influenced by culture, politics, and society. These influences extend down to the most detailed mechanisms for measuring malnutrition and providing sustenance. As the book shows, over the past century, the humanitarian approach to hunger has redefined food as nutrients and hunger as a medical condition. Aid has become more individualized, medicalized, and rationalized, shaped by modernism in bureaucracy, commerce, and food technology. The book focuses on the gains and losses that result, examining the complex compromises that arise between efficiency of distribution and quality of care. It concludes that humanitarian groups have developed an approach to the empty stomach that is dependent on compact, commercially produced devices and is often paternalistic and culturally insensitive.
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Endicott, Timothy. Administrative Law. 5. Aufl. Oxford University Press, 2021. http://dx.doi.org/10.1093/he/9780192893567.001.0001.
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Administrative Law explains the constitutional principles of the subject and their application across the range of twenty-first-century administrative law. The focus on constitutional principles is meant to bring some order to the very diverse topics with which you need to deal if you are to understand this very complex branch of public law. The common law courts, government agencies, and Parliament have developed a wide variety of techniques for controlling the enormously diverse activities of twenty-first-century government. Underlying all that variety is a set of constitutional principles. This book uses the law of judicial review to identify and to explain these principles, and then shows how they ought to be worked out in the private law of tort and contract, in the tribunals system, and in non-judicial techniques such as investigations by ombudsmen, auditors, and other government agencies. The aim is to equip the reader to take a principled approach to the controversial problems of administrative law.
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Lake, Morris. Australian Forest Woods. CSIRO Publishing, 2019. http://dx.doi.org/10.1071/9781486307791.
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Australian Forest Woods describes about 130 of the most significant Australian forest trees and their wood. The introductory sections introduce the reader to the uniqueness and usefulness of forest trees. The book examines the forest tree species and their wood with photographs, botanical descriptions and a summary of the characteristics of the wood. A section on wood identification includes fundamental information on tree growth and wood structure.
With over 900 images, this is the most comprehensive guide ever written on Australian forest woods, both for the amateur and the professional wood enthusiast. Macrophotographs of the wood are shown in association with a physical description of wood characteristics, which will aid identification. This technique was developed by Jean-Claude Cerre, France, and his macrophotographs are included in the book.
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Greenough, Paul. The uneasy politics of epidemic aid: the CDC’s mission to Cold War East Pakistan, 1958. Manchester University Press, 2017. http://dx.doi.org/10.7228/manchester/9781526110886.003.0002.
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Global smallpox eradication was achieved only after decades of unsuccessful experiments in smallpox-endemic countries. A case in point occurred in 1958 when a severe epidemic imposed heavy mortality on East Pakistan. In response a Bengali regional-nationalist ‘Citizens Provincial Epidemic Control Committee’ pushed aside the provincial health department and launched an eradication campaign based on student volunteers using foreign-donated vaccine. In a period of ten weeks thousands of volunteers vaccinated thirty million Bengalis, albeit relying on shortcuts in sterile technique and neglect of patient record-keeping. The US government, in support of its Cold War ally, Pakistan, provided half of the vaccine supplies. The US also sent a team of Communicable Disease Center epidemiologists to assist public health officials. The team, led by Alexander D. Langmuir, proposed ‘active surveillance’ methods but was constrained by T. Aidan Cockburn, the Chief Public Health Adviser, who favored the Bengalis’ volunteer approach. A struggle developed between politicised volunteerism and epidemiological professionalism, and the CDC experts failed to prevail. The two sides' published reports thus made contradictory recommendations to the global campaign, but subsequent experience has shown that both mass participation and active surveillance are critical ingredients for successful disease control and eradication programmes.
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VanCour, Shawn. Making Radio. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780190497118.001.0001.
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The opening decades of the twentieth century witnessed a profound transformation in the history of modern sound media, with workers in US film, radio, and record industries developing pioneering production methods and performance styles tailored to emerging technologies of electric sound reproduction that directly shaped dominant forms and experiences of modern sound culture. Focusing on broadcasting’s initial expansion period during the 1920s, Making Radio explores the forms of creative labor pursued for the medium before the better-known network era of the 1930s and 1940s, assessing their role in shaping radio’s own identity and identifying affinities with parallel practices pursued for conversion-era film and phonography. Tracing programming forms adopted by early radio writers and programmers, production techniques developed by studio engineers, and performance styles cultivated by on-air talent, it shows how radio workers negotiated a series of broader industrial and cultural pressures to establish best practices for their medium. In the process, it argues, these sound workers shaped not only the future of broadcasting, but also contributed to much broader shifts in popular forms of music, drama, and public oratory, ushering in a new era of electric sound entertainment.
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Lake, Morris. Australian Rainforest Woods. CSIRO Publishing, 2015. http://dx.doi.org/10.1071/9781486301805.
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Australian Rainforest Woods describes 141 of the most significant Australian rainforest trees and their wood. The introductory sections draw the reader into an understanding of the botanical, evolutionary, environmental, historical and international significance of this beautiful but finite Australian resource. The main section examines the species and their wood with photographs, botanical descriptions and a summary of the characteristics of the wood. A section on wood identification includes fundamental information on tree growth and wood structure, as well as images of the basic characteristics.
With more than 900 colour images, this is the most comprehensive guide ever written on Australian rainforest woods, both for the amateur and the professional wood enthusiast. It is the first time that macrophotographs of the wood have been shown in association with a physical description of wood characteristics, which will aid identification. This technique was developed by Jean-Claude Cerre, France, and his macrophotographs are included in the book.
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Keohane, Georgia Levenson. Capital and the Common Good. Columbia University Press, 2017. http://dx.doi.org/10.7312/columbia/9780231178020.001.0001.
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Despite social and economic advances around the world, poverty and disease persist, exacerbated by the mounting challenges of climate change, natural disasters, political conflict, mass migration, and economic inequality. While governments commit to addressing these challenges, traditional public and philanthropic dollars are not enough. Here, innovative finance has shown a way forward: by borrowing techniques from the world of finance, we can raise capital for social investments today. Innovative finance has provided polio vaccines to children in the DRC, crop insurance to farmers in India, pay-as-you-go solar electricity to Kenyans, and affordable housing and transportation to New Yorkers. It has helped governmental, commercial, and philanthropic resources meet the needs of the poor and underserved and build a more sustainable and inclusive prosperity. Capital and the Common Good shows how market failure in one context can be solved with market solutions from another: an expert in securitization bundles future development aid into bonds to pay for vaccines today; an entrepreneur turns a mobile phone into an array of financial services for the unbanked; and policy makers adapt pay-for-success models from the world of infrastructure to human services like early childhood education, maternal health, and job training. Revisiting the successes and missteps of these efforts, Georgia Levenson Keohane argues that innovative finance is as much about incentives and sound decision-making as it is about money. When it works, innovative finance gives us the tools, motivation, and security to invest in our shared future.
Buchteile zum Thema "Air shower technique"
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Healy, Robert, Tapajit Dey, Kieran Conboy und Brian Fitzgerald. „A Novel Technique to Assess Agile Systems for Stability“. In Lecture Notes in Business Information Processing, 20–33. Cham: Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-33976-9_2.
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AbstractAgile systems, like the Kanban and Scrum frameworks, are built on assumptions of sustainability and stability, however, there is little empirical evidence on whether such systems are stable in practice or not. Therefore, in this study we aim to inspect the stability of Agile systems by leveraging the concept of stability described in Queueing Theory. We define a novel metric, the Stability Metric, as a way of assessing queueing systems, especially Agile systems. We inspect 926 Jira projects in 14 organizations with over 1.6 million product backlog items using this metric. The analysis showed that 72.89% of these Jira projects were not stable and stable systems, on average, had product backlog sizes 10 times shorter than unstable ones. These results suggest that while the goal of Agile is to create a sustainable, stable way of working, this is not guaranteed, and a better understanding of systems and queues may be required to help design, create, coach, and maintain optimal Agile systems.
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Gellermann, Thorsten, Meinolf Sellmann und Robert Wright. „Shorter Path Constraints for the Resource Constrained Shortest Path Problem“. In Integration of AI and OR Techniques in Constraint Programming for Combinatorial Optimization Problems, 201–16. Berlin, Heidelberg: Springer Berlin Heidelberg, 2005. http://dx.doi.org/10.1007/11493853_16.
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Rossella, Stocco, Pirrera Laura und Cellini Emilio. „L’applicazione di tecniche innovative nel monitoraggio costiero degli habitat prioritari“. In Proceedings e report, 620–31. Florence: Firenze University Press, 2020. http://dx.doi.org/10.36253/978-88-5518-147-1.62.
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The aim of the present paper is to define the advantage to use innovative techniques based on sperimental tool to supplement the traditional techniques in marine monitoring, through experience of CRSM-ARPACAL (Centro Regionale Strategia Marina) into two regional projects called "SIC Carlit" and "Musmap". Both projects have shown that in the monitoring of coastal marine ecosystems the sperimental techniques to supplement traditional methods can provide more accurate and data with reduced costs and times of work.
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Denzel, Markus A. „Bookkeeping as a ‘key technology’ of pre-modern commerce. Its relevance for the eco-nomic development in Europe“. In L’economia della conoscenza: innovazione, produttività e crescita economica nei secoli XIII-XVIII / The knowledge economy: innovation, productivity and economic growth, 13th to 18th century, 209–35. Florence: Firenze University Press, 2023. http://dx.doi.org/10.36253/979-12-215-0092-9.14.
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It is the aim of this paper to analyse the importance of (double-entry) bookkeeping for the economic development in Europe and its possible indirect influence on economic growth. Being one of the most important commercial techniques of the European merchants double-entry bookkeeping stayed in close relationship to the expansion of trade. So, the distribution of different bookkeeping techniques all over Western and Central Europe, took place, on one hand, through the extensive commercial contacts of Italian merchant-bankers with merchants of regions north of the Alps and because of the need of many non-Italian merchants to consolidate their commercial knowledge in Italy through specific studies and/or through acquiring practical knowledge. On the other, treaties on (double-entry) bookkeeping supported its diffusion. The study analyses examples of ledgers as ‘mirrors’ of their enterprises’ activities, and it will be shown how such ledgers served as instruments for reducing various risks of entrepreneurial engagement. As a result it will become clear that the knowledge of the technique of double-entry bookkeeping was one of the preconditions of the commercial and, later on, the industrial expansion of the Europeans, which made a significant difference to other merchant cultures in the world.
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Risoli, Samuele, Sabrina Sarrocco, Giuliana Terracciano, Riccardo Baroncelli, Marco Alberto Luca Zuffi, Cecilia Mancusi und Cristina Nali. „Isolation and molecular characterization of Fusarium species (Fungi, Ascomycota) from unhatched eggs of Caretta caretta in Tuscany (Italy)“. In Ninth International Symposium “Monitoring of Mediterranean Coastal Areas: Problems and Measurement Techniques”, 747–55. Florence: Firenze University Press, 2022. http://dx.doi.org/10.36253/979-12-215-0030-1.71.
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Caretta caretta is the only sea turtle species nesting along the Tuscan coastline, where nests are becoming more numerous and widespread, as well as the number of Sea Turtle Egg Fusariosis (STEF)-affected eggs. In this work, we analyzed eggs from natural nests of C. caretta that showed visual symptoms of STEF from Tuscan nests, with the aim to (i) isolate Fusarium spp. strains present in unhatched eggs, (ii) morphologically and molecularly characterize the isolated fungi and, finally, (iii) reconstruct the phylogenetic relationships between our isolates and those already known.
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Dorigatti, Josip, Tina Peric und Gorana Jelic Mrcelic. „Marine protected areas and the problem of paper parks“. In Ninth International Symposium “Monitoring of Mediterranean Coastal Areas: Problems and Measurement Techniques”, 211–20. Florence: Firenze University Press, 2022. http://dx.doi.org/10.36253/979-12-215-0030-1.19.
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Paper aim is to overview paper parks problem regarding Marine Protected Areas (MPAs). Ocean makes Earth habitable for humankind; careful management of ocean is a key feature of sustainable future. MPAs are a key instrument of ocean protection; MPAs effective management is essential to reduce environmental challenges. A 2017 WWF report highlighted that EU protected areas were at risk due to lack of proper implementation of EU laws by member states and the Commission legal actions. The Report showed the importance of both management plans and to involve all stakeholders in its developing process
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Singh, Chandan, Wooseok Ha und Bin Yu. „Interpreting and Improving Deep-Learning Models with Reality Checks“. In xxAI - Beyond Explainable AI, 229–54. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-04083-2_12.
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AbstractRecent deep-learning models have achieved impressive predictive performance by learning complex functions of many variables, often at the cost of interpretability. This chapter covers recent work aiming to interpret models by attributing importance to features and feature groups for a single prediction. Importantly, the proposed attributions assign importance to interactions between features, in addition to features in isolation. These attributions are shown to yield insights across real-world domains, including bio-imaging, cosmology image and natural-language processing. We then show how these attributions can be used to directly improve the generalization of a neural network or to distill it into a simple model. Throughout the chapter, we emphasize the use of reality checks to scrutinize the proposed interpretation techniques. (Code for all methods in this chapter is available at "Image missing"github.com/csinva and "Image missing"github.com/Yu-Group, implemented in PyTorch [54]).
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Malcangio, Daniela, Daniele Celli, Umberto Fratino, Maria Francesca Bruno, Matteo Gianluca Molfetta, Luigi Pratola, Stefania Geronimo, Adriana Maria Lotito, Paolo Francesco Garofoli und Marcello Di Risio. „Biodiversity smart monitoring guided by historical analysis of coastal evolution“. In Ninth International Symposium “Monitoring of Mediterranean Coastal Areas: Problems and Measurement Techniques”, 504–14. Florence: Firenze University Press, 2022. http://dx.doi.org/10.36253/979-12-215-0030-1.46.
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The present work focuses on the preparatory phase of the design of the biodiversity monitoring network. The preliminary results of this first phase are then presented, starting from the formation of a cognitive framework based on previous knowledge of environmental parameters, the definition of sampling stations, areas, and detection points. At the same time, the results of the analysis of the evolutionary dynamics of the coasts are shown in the light of the new analyses and new measures, which, together with existing data, aim to inform the monitoring strategy.
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Colella, Micol, Micaela Liberti, Francesca Apollonio und Giorgio Bonmassar. „A Miniaturized Ultra-Focal Magnetic Stimulator and Its Preliminary Application to the Peripheral Nervous System“. In Brain and Human Body Modeling 2020, 167–76. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-45623-8_9.
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AbstractTranscranial magnetic stimulation (TMS) is a noninvasive brain stimulation technique used in the clinic to treat several neurological disorders and psychiatric diseases. One of TMS’s significant limitations is its low spatial resolution, which often results in a mismatch between the target area in the brain and the stimulation site on the scalp. To enhance its spatial resolution, we designed and built a complete stimulation system complete with a millimetric-diameter coil and microscopic traces (μCoil). The first tests conducted on healthy volunteers showed that the μCoil stimulation of the radial nerve in the wrist could indeed evoke somatosensory nerve action potentials (SNAPs). In this chapter, we study this nerve stimulation system with electromagnetic and neuron simulators on a neurofunctionalized model from the Virtual Population (ViP v.4) and a μCoil figure-8 geometry. In particular, we study how changes in the μCoil geometry, such as the number of layers, shape, and length of an iron or air core, may help to promote the generation of somatosensory nerve action potentials.
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Prasad, Kumar Shantanu, Gbanaibolou Jombo, Sikiru O. Ismail, Yong K. Chen und Hom N. Dhakal. „Quantitative Assessment of Damage in Composites by Implementing Acousto-ultrasonics Technique“. In Springer Proceedings in Energy, 209–17. Cham: Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-30960-1_20.
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AbstractThis study focused on quantitative damage severity assessment in composite materials using Acousto-Ultrasonics (AU), an in-service and active non-destructive inspection technique in which Lamb waves are communicated through a damaged zone. This was done by activating a signal onto the composite material surface and acquiring the received waves after their interactions with the damage. It relied on early research that presented a series of stress wave factors (SWFs) derived from the frequency-domain of the AU data, as quantitative identifiers of the received signal. Although, the SWFs have previously been proven to determine the understanding of the spatial arrangements of the impact damage, the degree or severity of the damage inside the impact damage area has not been assessed. Therefore, the current research was a step in the right way toward that aim. AU waves were generated via a laminate with increasing concentrations of ply faults, across longitudinal length. The stress wave factors were first examined for an undamaged composite, and the SWFs were then connected with the fault concentration. The significance of the found linkages and the possible futures of quantitative assessment of the degree of damage by such relationships were examined. The stress wave factors showed clear and consistent patterns, as the fault concentration increased. With a rise in fault density, an element measuring the energy content of the waves significantly changed with R-sq(adj) = 91.33% and almost linearly, and provided a robust measurable trend, while other parameter exhibited lesser shifts with R-sq(adj) = 51.86%. The result obtained from the presented work provided a base to cost-effective and in-service measure to early detection of catastrophic failures in composite structures, including the wind turbine blades for renewable and sustainable energy generation.
Konferenzberichte zum Thema "Air shower technique"
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Emery, Gabriel, Cyril Martin Alispach, Hyuga Abe, Arnau Aguasca, Ivan Agudo, Lucio Angelo Antonelli, Carla Aramo et al. „Reconstruction of extensive air shower images of the Large Size Telescope prototype of CTA using a novel likelihood technique“. In 37th International Cosmic Ray Conference. Trieste, Italy: Sissa Medialab, 2021. http://dx.doi.org/10.22323/1.395.0716.
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Panda, Rajesh Kumar, und B. V. S. S. S. Prasad. „Flow Visualization and Conjugate Heat Transfer Study From Shower Head Impinging Jets“. In ASME 2011 Turbo Expo: Turbine Technical Conference and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/gt2011-45098.
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Computational and experimental investigations on a flat circular disk are reported with a constant heat flux imposed on its bottom surface and a shower head of air jets impinging on the top surface. The shower head consists of a central jet surrounded by four neighboring perimeter jets. Lamp black flow visualization technique and computations using shear stress transport (SST) κ-ω turbulence model are employed to describe the complex interaction of the wall jets and the associated flow structure. Thermochromic liquid crystal measurement technique is used for surface temperature measurement. The formations of saddle point, nodal point of attachment, nodal point of separation, flow separation line and the up-wash flow are identified. It is observed that the flow topology is practically independent of Reynolds number within the investigated range but is significantly altered with the spacing between the jet orifice and the target surface. A strong correlation between the Nusselt number and the pressure distribution is noticed. Local variation of heat transfer rate with varying plate spacing to jet diameter ratio is significant but its effect on the area weighted average heat transfer rate is small. When compared with a single jet of equal mass flow rate and Reynolds number, the shower head jets provide higher heat transfer rate but require more power for pumping.
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Zhang, Luzeng J., und Ram Pudupatty. „The Effects of Injection Angle and Hole Exit Shape on Turbine Nozzle Pressure Side Film Cooling“. In ASME Turbo Expo 2000: Power for Land, Sea, and Air. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/2000-gt-0247.
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Using the pressure sensitive paint (PSP) technique, film cooling effectiveness was measured on a turbine vane pressure surface, with a four-row showerhead cooling hole configuration and a single row of holes on the pressure side. Nitrogen gas was used to simulate film cooling flow providing an oxygen concentration map corresponding to an effectiveness map by the mass transfer analogy. Three showerhead coolant injection angles (45°, 90°, and 135°) were studied and two pressure side injection angles (20° and 40°) for cylindrical holes and a 40° angle for shaped hole were studied. In addition, studies were performed on three combinations of shower head and pressure side injections. Film effectiveness was measured for each of the cases at three blowing ratios. The pressure sensitive paint (PSP) was used to indicate oxygen concentration and was calibrated at various temperatures and pressures to obtain better accuracy before being applied to the airfoil surface. The results indicate that 45° spanwise angle injection provides best film coverage for the shower head injections. For pressure side injections, the 20° cylindrical hole injection results in the highest effectiveness values and the shaped hole improves film effectiveness immediately downstream from the injection point. The film effectiveness for three combined injections and the interaction between showerhead injection and the pressure side injection are also presented and discussed.
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Vrabel, Michal, Jan Genci und Pavol Bobik. „Low-level computer vision techniques for processing of extensive air shower track images“. In 2017 IEEE 14th International Scientific Conference on Informatics. IEEE, 2017. http://dx.doi.org/10.1109/informatics.2017.8327287.
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Dobrzynski, B., H. Saathoff, G. Kosyna, C. Clemen und V. Gu¨mmer. „Active Flow Control in a Single-Stage Axial Compressor Using Tip Injection and Endwall Boundary Layer Removal“. In ASME Turbo Expo 2008: Power for Land, Sea, and Air. ASMEDC, 2008. http://dx.doi.org/10.1115/gt2008-50214.
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Different active flow control techniques have been investigated in a 1.5-stage axial-flow compressor. Looking at a low-speed single-stage environment, many researchers have shown that highly loaded compressors are tip critical, showing stall inception caused by short length scale disturbances (spikes). It has been shown by several authors that these disturbances are related to the spillage of endwall flow ahead of the blading (spill forward). For the present work, different tip injection configurations were investigated in order to stabilize the near casing flow, increasing the operating range of the compressor. Stall margin improvement and the impact on stage efficiency are compared and discussed. Oil flow pictures of the casing wall above the rotor and of the stator blades as well as traverse data from pneumatic 5-hole probes show the impact of flow control on rotor and stator performance. Another method of energizing the casing wall boundary layer is the removal of low energy fluid by a circumferential slot above the rotor, which was also studied experimentally. Again, the impact on compressor operating range and efficiency, as well as flow field information collected by oil flow visualization and traverse data are discussed. Comparing the different flow control techniques, it is shown that increasing stall margin is not directly linked to stage efficiency. As described in various publications, discrete tip injection is a very powerful technique as far as range extension is concerned, but it also has substantial drawbacks such as the circumferential inhomogeneity of the rotor exit flow. These inhomogeneities may result in poor stator performance, overall resulting in a drop of stage efficiency. This problem does not occur if circumferential boundary layer removal above the rotor is used. This method however shows much less potential for increasing the operating range.
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Pinelli, M., und M. Venturini. „Application of Methodologies to Evaluate the Health State of Gas Turbines in a Cogenerative Combined Cycle Power Plant“. In ASME Turbo Expo 2002: Power for Land, Sea, and Air. ASMEDC, 2002. http://dx.doi.org/10.1115/gt2002-30248.
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In the paper, a comprehensive methodology for gas turbine health state determination is applied to a single-shaft Fiat Avio TG 20 gas turbine working in the cogenerative combined cycle power plant of Fiat – Mirafiori (Italy). In order to determine operating state variations from new and clean condition, the following procedures were applied to historical field measurements: • normalization procedure to determine the variations between measured and expected values; • inverse cycle technique to calculate the values of the characteristic parameters that are indices of the machine health state. The application of these techniques to long period operating data allowed measurement validation and the determination of the machine health state. The results showed the good capability of the developed techniques for the determination and the analysis of performance drop due to compressor fouling and to turbine malfunction.
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Bladh, Ronnie, Matthew P. Castanier und Christophe Pierre. „Component-Mode-Based Reduced Order Modeling Techniques for Mistuned Bladed Disks: Part II — Application“. In ASME Turbo Expo 2000: Power for Land, Sea, and Air. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/2000-gt-0361.
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In this paper, the component-mode-based methods formulated in the companion paper (Part I: Theoretical Models) are applied to the dynamic analysis of two example finite element models of bladed disks. Free and forced responses for both tuned and mistuned rotors are considered. Comprehensive comparisons are made among the techniques using full system finite element solutions as a benchmark. The accurate capture of eigenfrequency veering regions is of critical importance for obtaining high-fidelity predictions of the rotor’s sensitivity to mistuning. Therefore, particular attention is devoted to this subject. It is shown that the Craig-Bampton component mode synthesis (CMS) technique is robust and yields highly reliable results. However, this is achieved at considerable computational cost due to the retained component interface degrees of freedom (DOF). It is demonstrated that this problem is alleviated by a secondary modal analysis reduction technique (SMART). In addition, a non-CMS mistuning projection method is considered. Although this method is elegant and accurate, it is seen that it lacks the versatility and efficiency of the CMS-based SMART. Overall, this work shows that significant improvements on the accuracy and efficiency of current reduced order modeling methods are possible.
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Jenkins, Sean C., Igor V. Shevchuk, Jens von Wolfersdorf und Bernhard Weigand. „Transient Thermal Field Measurements in a High Aspect Ratio Channel Related to Transient Thermochromic Liquid Crystal Experiments“. In ASME Turbo Expo 2007: Power for Land, Sea, and Air. ASMEDC, 2007. http://dx.doi.org/10.1115/gt2007-27812.
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Measurements of transient fluid temperature distributions were made in a high aspect ratio (4:1) internally ribbed two-pass channel relating to the measurement of heat transfer using the transient thermochromic liquid crystal (TLC) technique. The temperature field was measured at several positions leading up to and around the 180° bend in a two-passage channel to account for variations in the bulk temperature used as a reference for the transient TLC technique. Results showed that the normalized distribution of the temperature field was time-invariant, an important result for the validation of heat transfer results using the transient TLC method. The normalized fluid temperature field was shown to be independent of the inlet temperature step and relatively independent of channel Reynolds number. Fluid temperature distributions were shown to be consistent over the length of the inlet channel, however, temperature field measurements made downstream of the bend exhibited a strong asymmetry. Finally, local temperature distributions were used to adjust the reference temperature used in calculating heat transfer coefficient distributions and to show the behavior of heat transfer due to 180° bends.
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Prachayawarakorn, Somkiat, E. Saniso, T. Swasdisewi und S. Soponronnarit. „Process of parboiling rice by microwave-assisted hot air fluidized bed technique“. In 21st International Drying Symposium. Valencia: Universitat Politècnica València, 2018. http://dx.doi.org/10.4995/ids2018.2018.7541.
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In this work the new process of producing parboiled rice (PB) by combinatintion of microwave and hot air fluidized bed (MWFB) was proposed and investigated. Results showed that the drying time was shorter with smaller bed depth, higher drying temperature and higher microwave power. The initial grain temperature, drying temperature, bed depth and microwave power strongly affected the gelatinization of rice starch. The PB produced by MWFB caused a very small broken kernel (1-2%). The whiteness was decreased with increase in drying time, initial grain temperature, drying temperature and microwave power. The specific energy consumption was increased with increasing such operating parameters.Keywords: Drying; Parboiled rice; Fluidized bed; Microwave.
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Dhiman, Sushant, und Savas Yavuzkurt. „Film Cooling Calculations With an Iterative Conjugate Heat Transfer Approach Using Empirical Heat Transfer Coefficient Corrections“. In ASME Turbo Expo 2010: Power for Land, Sea, and Air. ASMEDC, 2010. http://dx.doi.org/10.1115/gt2010-22958.
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An iterative conjugate heat transfer technique has been developed to predict the temperatures on film cooled surfaces such as flat plates and turbine blades. Conventional approaches using a constant wall temperature to calculate heat transfer coefficient and applying it to solid as a boundary condition can result in errors around 14% in uncooled blade temperatures. This indicates a need for conjugate heat transfer calculation techniques. However, full conjugate calculations also suffer from inability to correctly predict heat transfer coefficients in the near field of film cooling holes and require high computational cost making them impractical for component design in industrial applications. Iterative conjugate heat transfer (ICHT) analysis is a compromise between these two techniques where the external flow convection and internal blade conduction are loosely coupled. The solution obtained from solving one domain is used as boundary condition for the other. This process is iterated until convergence. Flow and heat transfer over a film cooled blade is not solved directly and instead convective heat transfer coefficients resulting from external convection on a similar blade without film cooling and under the same flow conditions are corrected by use of experimental data to incorporate the effect of film cooling in the heat transfer coefficients. The effect of conjugate heat transfer is taken into account by using this iterative technique. Unlike full conjugate heat transfer (CHT) the ICHT analysis doesn’t require solving a large number of linear algebraic equations at once. It uses two separate meshes for external convection and blade conduction and thus problem can be solved in lesser time using less computational resources. A demonstration of this technique using a commercial CFD solver FLUENT is presented for simulations of film cooling on flat plates. Results are presented in form of film cooling heat transfer coefficients and surface temperature distribution which are compared with results obtained from conventional approach. For uncooled surfaces, the deviations were as high as 3.5% between conjugate and conventional technique results for the wall temperature. For film cooling simulations on a flat plate using the ICHT approach showed deviations up to 10% in surface temperature compared to constant wall temperature technique for a high temperature difference case and 3% for a low temperature difference case, since surface temperature is not constant over the surface when conjugate heat transfer is considered. Results show that conjugate heat transfer effect is significant for film cooling flows involving high temperature differences for the current blade materials and application of film cooling correction obtained from experimental data is very useful in obtaining realistic blade temperatures.
Berichte der Organisationen zum Thema "Air shower technique"
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Belz, J., Z. Cao, P. Huentemeyer, C. C. H. Jui, K. Martens, J. Matthews, M. Maestas et al. Comparison of Air Fluorescence and Ionization Measurements of E.M. Shower Depth Profiles: Test of a UHECR Detector Technique. Office of Scientific and Technical Information (OSTI), Oktober 2005. http://dx.doi.org/10.2172/878086.
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Chong, Alberto E., Mark Gradstein und María Cecilia Calderón. Foreign Aid, Income Inequality, and Poverty. Inter-American Development Bank, März 2006. http://dx.doi.org/10.18235/0010965.
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The aim of this paper is to provide empirical evidence on the link between foreign aid and income inequality for the period 1973-2002. Since simple cross-country regressions cannot be taken as true time series findings, we also focus on dynamic panel data techniques, which allow accounting for potential simultaneity and heterogeneity problems. We do not find very robust evidence that foreign aid is conducive to the improvement of the distribution of income, even when the quality of institutions is taken into account. This finding is consistent with recent empirical research on aid and growth that shows that such a link is weak at best.
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Cender, Clinton, Catherine Thomas, Benjamin Greeling, Bradley Sartain, Ashley Gonzalez und Martin Page. Pilot-scale optimization : Research on Algae Flotation Techniques (RAFT). Engineer Research and Development Center (U.S.), Oktober 2023. http://dx.doi.org/10.21079/11681/47722.
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The impacts of harmful algal blooms (HABs) on US national waterways continue to cause significant economic and environmental damage. Re-searchers at the US Army Engineer Research and Development Center successfully demonstrated the Research on Algae Flotation Techniques (RAFT) project at pilot scale. This study was designed to show that the sur-face concentrations of algal biomass can be effectively increased with near linear scalability utilizing the natural methods by which some algae entrap air within excreted mucilage for flotation. The surface concentration of cyanobacteria measured as phycocyanin pigment increased by six-fold after RAFT flocculation treatment. Further optimization of chemical delivery systems, mixing, and dissolved air exposure will be required before full scale readiness.
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Tanny, Josef, Gabriel Katul, Shabtai Cohen und Meir Teitel. Micrometeorological methods for inferring whole canopy evapotranspiration in large agricultural structures: measurements and modeling. United States Department of Agriculture, Oktober 2015. http://dx.doi.org/10.32747/2015.7594402.bard.
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Original objectives and revisions The original objectives as stated in the approved proposal were: (1) To establish guidelines for the use of micrometeorological techniques as accurate, reliable and low-cost tools for continuous monitoring of whole canopy ET of common crops grown in large agricultural structures. (2) To adapt existing methods for protected cultivation environments. (3) To combine previously derived theoretical models of air flow and scalar fluxes in large agricultural structures (an outcome of our previous BARD project) with ET data derived from application of turbulent transport techniques for different crops and structure types. All the objectives have been successfully addressed. The study was focused on both screenhouses and naturally ventilated greenhouses, and all proposed methods were examined. Background to the topic Our previous BARD project established that the eddy covariance (EC) technique is suitable for whole canopy evapotranspiration measurements in large agricultural screenhouses. Nevertheless, the eddy covariance technique remains difficult to apply in the farm due to costs, operational complexity, and post-processing of data – thereby inviting alternative techniques to be developed. The subject of this project was: 1) the evaluation of four turbulent transport (TT) techniques, namely, Surface Renewal (SR), Flux-Variance (FV), Half-order Time Derivative (HTD) and Bowen Ratio (BR), whose instrumentation needs and operational demands are not as elaborate as the EC, to estimate evapotranspiration within large agricultural structures; and 2) the development of mathematical models able to predict water savings and account for the external environmental conditions, physiological properties of the plant, and structure properties as well as to evaluate the necessary micrometeorological conditions for utilizing the above turbulent transfer methods in such protected environments. Major conclusions and achievements The major conclusions are: (i) the SR and FV techniques were suitable for reliable estimates of ET in shading and insect-proof screenhouses; (ii) The BR technique was reliable in shading screenhouses; (iii) HTD provided reasonable results in the shading and insect proof screenhouses; (iv) Quality control analysis of the EC method showed that conditions in the shading and insect proof screenhouses were reasonable for flux measurements. However, in the plastic covered greenhouse energy balance closure was poor. Therefore, the alternative methods could not be analyzed in the greenhouse; (v) A multi-layered flux footprint model was developed for a ‘generic’ crop canopy situated within a protected environment such as a large screenhouse. The new model accounts for the vertically distributed sources and sinks within the canopy volume as well as for modifications introduced by the screen on the flow field and microenvironment. The effect of the screen on fetch as a function of its relative height above the canopy is then studied for the first time and compared to the case where the screen is absent. The model calculations agreed with field experiments based on EC measurements from two screenhouse experiments. Implications, both scientific and agricultural The study established for the first time, both experimentally and theoretically, the use of four simple TT techniques for ET estimates within large agricultural screenhouses. Such measurements, along with reliable theoretical models, will enable the future development of lowcost ET monitoring system which will be attainable for day-to-day use by growers in improving irrigation management.
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Wagner, Anna, Jon Maakestad, Edward Yarmak und Thomas Douglas. Artificial ground freezing using solar-powered thermosyphons. Engineer Research and Development Center (U.S.), November 2021. http://dx.doi.org/10.21079/11681/42421.
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Thermosyphons are an artificial ground-freezing technique that has been used to stabilize permafrost since the 1960s. The largest engineered structure that uses thermosyphons to maintain frozen ground is the Trans Alaska Pipeline, and it has over 124,000 thermosyphons along its approximately 1300 km route. In passive mode, thermosyphons extract heat from the soil and transfer it to the environment when the air temperature is colder than the ground temperature. This passive technology can promote ground cooling during cold winter months. To address the growing need for maintaining frozen ground as air temperatures increase, we investigated a solar-powered refrigeration unit that could operate a thermosyphon (nonpassive) during temperatures above freezing. Our tests showed that energy generated from the solar array can operate the refrigeration unit and activate the hybrid thermosyphon to artificially cool the soil when air temperatures are above freezing. This technology can be used to expand the application of thermosyphon technology to freeze ground or maintain permafrost, particularly in locations with limited access to line power.
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Urban, Angela, Ioannis Wallingford, Stephen Cosper, Abigail Rice, Whitney Wolf, H. Anderson, Michael Wolford, Chad Gemeinhardt und David Stokes. Standard Operating Procedure (SOP) for open-air solid waste burning in contingency locations. Engineer Research and Development Center (U.S.), September 2022. http://dx.doi.org/10.21079/11681/45363.
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Service engineer doctrine and field manuals, such as Army Techniques Publication 3-34.40, Technical Manual 5-634, and Army Regulation 420-1, offer guidance on solid waste management but do not provide the level of detail and practical guidance for open-air burning of solid waste to reduce risk to the Warfighter. Studies have shown that there could be ill health effects to service members from exposure to toxins from open-air burning. Further practical guidance is necessary to ensure that if there are no other means available for solid waste disposal, the risks associated with open-air burning are minimized as much as possible during contingency operations. Commands have limited resources and reduced personnel available to study which open-air burning procedures are optimal based on readiness and mission requirements. Planning for efficiency and risk avoidance in open-air burning operations includes several facets (e.g., site planning, processing, and recordkeeping considerations). This special report provides operational guidance to minimize risk of open-air burning for the Warfighter and other joint service personnel, particularly when there is no other alternative to open-air burning, during initial phase operating a burn pit or for waste management planning to establish standard operating procedures.
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Powell, Andrew, und Matteo Bobba. Aid Effectiveness: Politics Matters. Inter-American Development Bank, Januar 2007. http://dx.doi.org/10.18235/0010874.
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The literature on aid effectiveness has focused more on recipient policies than the determinants of aid allocation yet a consistent result is that political allies obtain more aid from donors than non-allies. This paper shows that aid allocated to political allies is ineffective for growth, whereas aid extended to countries that are not allies is highly effective. The result appears to be robust across different specifications and estimation techniques. In particular, new methods are employed to control for endogeneity. The paper suggests that aid allocation should be scrutinized carefully to make aid as effective as possible.
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Tanny, Josef, Gabriel Katul, Shabtai Cohen und Meir Teitel. Application of Turbulent Transport Techniques for Quantifying Whole Canopy Evapotranspiration in Large Agricultural Structures: Measurement and Theory. United States Department of Agriculture, Januar 2011. http://dx.doi.org/10.32747/2011.7592121.bard.
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Original objectives and revisions The original objectives of this research, as stated in the approved proposal were: 1. To establish guidelines for the use of turbulent transport techniques as accurate and reliable tool for continuous measurements of whole canopy ET and other scalar fluxes (e.g. heat and CO2) in large agricultural structures. 2. To conduct a detailed experimental study of flow patterns and turbulence characteristics in agricultural structures. 3. To derive theoretical models of air flow and scalar fluxes in agricultural structures that can guide the interpretation of TT measurements for a wide range of conditions. All the objectives have been successfully addressed within the project. The only modification was that the study focused on screenhouses only, while it was originally planned to study large greenhouses as well. This was decided due to the large amount of field and theoretical work required to meet the objectives within screenhouses. Background In agricultural structures such as screenhouses and greenhouses, evapotranspiration (ET) is currently measured using lysimeters or sap flow gauges. These measurements provide ET estimates at the single-plant scale that must then be extrapolated, often statistically or empirically, to the whole canopy for irrigation scheduling purposes. On the other hand, turbulent transport techniques, like the eddy covariance, have become the standard for measuring whole canopy evapotranspiration in the open, but their applicability to agricultural structures has not yet been established. The subject of this project is the application of turbulent transport techniques to estimate ET for irrigation scheduling within large agricultural structures. Major conclusions and achievements The major conclusions of this project are: (i) the eddy covariance technique is suitable for reliable measurements of scalar fluxes (e.g., evapotranspiration, sensible heat, CO2) in most types of large screenhouses under all climatic conditions tested. All studies resulted with fair energy balance closures; (ii) comparison between measurements and theory show that the model is capable in reliably predicting the turbulent flow characteristics and surface fluxes within screenhouses; (iii) flow characteristics within the screenhouse, like flux-variance similarity and turbulence intensity were valid for the application of the eddy covariance technique in screenhouses of relatively dilute screens used for moderate shading and wind breaking. In more dense screens, usually used for insect exclusions, development of turbulent conditions was marginal; (iv) installation of the sensors requires that the system’s footprint will be within the limits of the screenhouse under study, as is the case in the open. A footprint model available in the literature was found to be reliable in assessing the footprint under screenhouse conditions. Implications, both scientific and agricultural The study established for the first time, both experimentally and theoretically, the use of the eddy covariance technique for flux measurements within agricultural screenhouses. Such measurements, along with reliable theoretical models, will enable more accurate assessments of crop water use which may lead to improved crop water management and increased water use efficiency of screenhouse crops.
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Wright, Louise, und Louise Crocker. PR-670-183826-R03 Extended Evaluation of LSM-Magnetostrictive Pipe Models. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), Mai 2021. http://dx.doi.org/10.55274/r0012097.
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Integrity assessment of pipelines is vital to ensure that oil and gas pipes have adequate strength to prevent leaks and ruptures. Regular inspections are conducted to confirm safe operation conditions of pipelines. The industry's principal method for assessing pipelines is in-line inspection (ILI), involving the passing of a device along the inside of a pipe to assess the condition of the pipeline. ILI devices can be fitted with a number of sensors allowing various measurement parameters to be obtained simultaneously. Not all pipelines are suited to ILI for reasons such as small diameter, obstructions within the pipe, or insufficient access to deploy or retrieve the ILI tools. These pipelines are sometimes referred to as 'difficult to inspect'. Alternative methods for examining pipeline condition are required with a range of technologies collectively known as Large Standoff Magnetometry (LSM) offering a promising solution for detection of pipe defects from a distance, reducing the need for excavation. LSM utilizes coupling between defects and changes in the magnetic properties of the pipeline material as a method for evaluation of pipe walls to identify the location of areas that require repair or further monitoring. Trials of existing commercial instruments by the pipeline industry have shown sufficient promise to investigate these technologies further. However, the vendors have supplied limited information on the underpinning physics of both the materials being tested and the instrument technology, meaning that further study is required in order to build confidence in the technique. The purpose of the project is to establish the ability of LSM to detect corrosion in API 5L pipe grades B to X70. The aim of the modelling work has been to use quantitative physics-based modelling techniques to predict the performance of LSM as a defect detection technique in situations that cannot easily be recreated in a laboratory environment, after validating the modelling approach by comparing measurements made in the laboratory to model results.
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Lahav, Ori, Albert Heber und David Broday. Elimination of emissions of ammonia and hydrogen sulfide from confined animal and feeding operations (CAFO) using an adsorption/liquid-redox process with biological regeneration. United States Department of Agriculture, März 2008. http://dx.doi.org/10.32747/2008.7695589.bard.
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The project was originally aimed at investigating and developing new efficient methods for cost effective removal of ammonia (NH₃) and hydrogen sulfide (H₂S) from Concentrated Animal Feeding Operations (CAFO), in particular broiler and laying houses (NH₃) and hog houses (H₂S). In both cases, the principal idea was to design and operate a dedicated air collection system that would be used for the treatment of the gases, and that would work independently from the general ventilation system. The advantages envisaged: (1) if collected at a point close to the source of generation, pollutants would arrive at the treatment system at higher concentrations; (2) the air in the vicinity of the animals would be cleaner, a fact that would promote animal growth rates; and (3) collection efficiency would be improved and adverse environmental impact reduced. For practical reasons, the project was divided in two: one effort concentrated on NH₃₍g₎ removal from chicken houses and another on H₂S₍g₎ removal from hog houses. NH₃₍g₎ removal: a novel approach was developed to reduce ammonia emissions from CAFOs in general, and poultry houses in particular. Air sucked by the dedicated air capturing system from close to the litter was shown to have NH₃₍g₎ concentrations an order of magnitude higher than at the vents of the ventilation system. The NH₃₍g₎ rich waste air was conveyed to an acidic (0<pH<~5) bubble column reactor where NH₃ was converted to NH₄⁺. The reactor operated in batch mode, starting at pH 0 and was switched to a new acidic absorption solution just before NH₃₍g₎ breakthrough occurred, at pH ~5. Experiments with a wide range of NH₃₍g₎ concentrations showed that the absorption efficiency was practically 100% throughout the process as long as the face velocity was below 4 cm/s. The potential advantages of the method include high absorption efficiency, lower NH₃₍g₎ concentrations in the vicinity of the birds, generation of a valuable product and the separation between the ventilation and ammonia treatment systems. A small scale pilot operation conducted for 5 weeks in a broiler house showed the approach to be technically feasible. H₂S₍g₎ removal: The main goal of this part was to develop a specific treatment process for minimizing H₂S₍g₎ emissions from hog houses. The proposed process consists of three units: In the 1ˢᵗ H₂S₍g₎ is absorbed into an acidic (pH<2) ferric iron solution and oxidized by Fe(III) to S⁰ in a bubble column reactor. In parallel, Fe(III) is reduced to Fe(II). In the 2ⁿᵈ unit Fe(II) is bio-oxidized back to Fe(III) by Acidithiobacillus ferrooxidans (AF).In the 3ʳᵈ unit S⁰ is separated from solution in a gravity settler. The work focused on three sub-processes: the kinetics of H₂S absorption into a ferric solution at low pH, the kinetics of Fe²⁺ oxidation by AF and the factors that affect ferric iron precipitation (a main obstacle for a continuous operation of the process) under the operational conditions. H₂S removal efficiency was found higher at a higher Fe(III) concentration and also higher for higher H₂S₍g₎ concentrations and lower flow rates of the treated air. The rate limiting step of the H₂S reactive absorption was found to be the chemical reaction rather than the transition from gas to liquid phase. H₂S₍g₎ removal efficiency of >95% was recorded with Fe(III) concentration of 9 g/L using typical AFO air compositions. The 2ⁿᵈ part of the work focused on kinetics of Fe(II) oxidation by AF. A new lab technique was developed for determining the kinetic equation and kinetic parameters (KS, Kₚ and mₘₐₓ) for the bacteria. The 3ʳᵈ part focused on iron oxide precipitation under the operational conditions. It was found that at lower pH (1.5) jarosite accumulation is slower and that the performance of the AF at this pH was sufficient for successive operation of the proposed process at the H₂S fluxes predicted from AFOs. A laboratory-scale test was carried out at Purdue University on the use of the integrated system for simultaneous hydrogen sulfide removal from a H₂S bubble column filled with ferric sulfate solution and biological regeneration of ferric ions in a packed column immobilized with enriched AFbacteria. Results demonstrated the technical feasibility of the integrated system for H₂S removal and simultaneous biological regeneration of Fe(III) for potential continuous treatment of H₂S released from CAFO. NH₃ and H₂S gradient measurements at egg layer and swine barns were conducted in winter and summer at Purdue. Results showed high potential to concentrate NH₃ and H₂S in hog buildings, and NH₃ in layer houses. H₂S emissions from layer houses were too low for a significant gradient. An NH₃ capturing system was designed and tested in a 100-chicken broiler room. Five bell-type collecting devices were installed over the litter to collect NH₃ emissions. While the air extraction system moved only 10% of the total room ventilation airflow rate, the fraction of total ammonia removed was 18%, because of the higher concentration air taken from near the litter. The system demonstrated the potential to reduce emissions from broiler facilities and to concentrate the NH₃ effluent for use in an emission control system. In summary, the project laid a solid foundation for the implementation of both processes, and also resulted in a significant scientific contribution related to AF kinetic studies and ferrous analytical measurements.