800 research outputs found
Experimental investigations on the fatigue resistance of automatically welded tubular X-joints for jacket support structures
The development within the offshore wind sector towards more powerful turbines combined with increasing water depth for new wind parks is challenging both the designer as well as the manufacturer of bottom fixed support structures. Besides XL-monopiles, the market developed an innovative and economic jacket support structure which is based on automatically manufactured tubular joints combined with standardized pipes. Besides the improvements for a serial manufacturing process the automatically welded tubular joints show a great potential in terms of fatigue resistance e.g. due to a smooth weld geometry without sharp notches. However, these benefits are not considered yet within the fatigue design process of automatically manufactured jacket substructures according to current standards due to the lack of suitable S-N curves. Therefore, 32 axial fatigue tests on single and double-sided automatically welded tubular X-joints have been performed to determine a new hot spot stress related S-N curve. Based on these constant amplitude fatigue tests a new S-N curve equal to a FAT 126 curve was computed which implicitly includes the benefits of the automatically welding procedure. © Published under licence by IOP Publishing Ltd
Soil fertility management for organic rice production in the Lao PDR
Rice is the most important agricultural commodity of the Lao People's Democratic Republic (Lao PDR), produced largely using traditional methods with limited inputs of fertilizers and other chemicals. The country has a wide diversity in rice production systems and rice varieties, with over 3000 different varieties recorded. The rich diversity and the production environment and methods are favorable for organic rice production. Investigations were carried out to describe soil fertility conditions, management practices, opportunities and problems associated with organic production methods for rice. Soils used for rice production are mostly of low fertility, with low organic matter and N-availability. In spite of this, virtually no fertilizer inputs are used for upland rice production. Inorganic fertilizer inputs for lowland rice production have increased rapidly over the past decade, but are still below 20 kg ha−1. The most important nutrient sources are rice straw and manure from buffalo and cattle. Chromolaena odorata plays an important role in nutrient cycling in upland rice systems and is sometimes added to lowland fields. In a range of fertility management studies, yield increase ranged from 2 to 89% for manure, straw or rice husk applied at modest rates (3 t ha−1), 32-156% for modest rates of inorganic fertilizer (60 kg N ha−1) and 36-167% for combined application of manure or crop residues with inorganic fertilizer. The response to locally produced commercial organic fertilizer was poor. The most promising inputs and strategies available to optimize yields in organic rice production systems are (1) optimizing use of locally available nutrients, mostly from manure, crop residues and weed biomass, (2) N addition through green manure and legumes growing in rotation and (3) additions of P through guano or rock-phosphate. The Lao PDR is fortunate to have substantial bat guano deposits in limestone caves. Extensive experience is available on straw and husk management for lowland systems and green manure species for upland production system
Discovering SUSY in the first LHC run
4 páginas, 1 figura.-- Trabajo presentado a la Fifth Conference on Physics at LHC celebrada en Hamburgo (Alemania) del 7 al 12 de junio de 2010.We analyze the potential of the first LHC physics run, assuming 1 fb−1 at ps = 7 TeV, to
discover Supersymmetry (SUSY). The results are based on SUSY parameter fits following a
frequentist approach. They include the experimental constraints from electroweak precision
data, (g − 2)μ, B physics and cosmological data. The two SUSY models under consideration
are the constrained MSSM (CMSSM) with universal soft supersymmetry-breaking
mass parameters, and a model with common non-universal Higgs mass parameters in the
superpotential (NUHM1). We find that large parts of the regions preferred at the 68%
C.L. are accessible to early LHC running.Work
supported in part by the European Community’s Marie-Curie Research Training Network under
contract MRTN-CT-2006-035505 ‘Tools and Precision Calculations for Physics Discoveries at
Colliders’ (HEPTOOLS).Peer reviewe
Разработка методики оптической идентификации сварных соединений
Выпускная квалификационная работа содержит 110 стр., 27 рис., 35 табл., 41 источник, 9 приложений.
Объектами исследования являются методы оптической двумерной и трехмерной реконструкции.
Цель работы – разработать методику идентификации сварных соединений контейнеров с ОЯТ и РАО.
В процессе исследования проводилась разработка методики идентификации текстурных особенностей поверхностей сварных соединений, рассмотрены вопросы технологии и компонентов систем реконструкции, рассмотрены аспекты социальной ответственности и финансового менеджмента.
В результате исследования разработана методики идентификации сварных соединений с помощью оптических методов сканирования.
Значимость работы состоит в том, что система позволяет увеличить эффективность систем идентификации учетных единиц.Master's thesis consist of 110 pages, 27 illustrations, 41 references and 9 attaches.
The objects of research are methods of optical two-dimensional and three-dimensional reconstruction.
Purpose of this work is to develop methodology for the identification containers welds with spent nuclear fuel and radioactive waste.
The study was carried out to develop methods of identification textural features of surfaces of welds, the issues of technology and components renovation systems, considered aspects of social responsibility and financial management.
This study developed a technique of identification of welded joints using optical scanning techniques.
The significance of the work lies in the fact that the system allows to increase the efficiency identification systems
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Tunable Nanometer Electrode Gaps by MeV Ion Irradiation
We report the use of MeV ion-irradiation-induced plastic deformation of amorphous materials to fabricate electrodes with nanometer-sized gaps. Plastic deformation of the amorphous metal is induced by ion irradiation, allowing the complete closing of a sub-micrometer gap. We measure the evolving gap size in situ by monitoring the field emission current-voltage (I-V) characteristics between electrodes. The I-V behavior is consistent with Fowler-Nordheim tunneling. We show that using feedback control on this signal permits gap size fabrication with atomic-scale precision. We expect this approach to nanogap fabrication will enable the practical realization of single molecule controlled devices and sensors.Engineering and Applied SciencesPhysic
Resonance model study of strangeness production in pp collisions
Results for the energy dependence of the elementary kaon production cross
sections in proton-proton collisions are reported. Calculations are performed
within an extended version of the resonance model which was used for the
previous studies of elementary kaon production in pion-nucleon and
pion- collisions. Although the model treatment is within the {\it
empirical} tree level (observed widths for the resonances are used), it is
fully relativistic, and includes all relevant baryon resonances up to 2 GeV.
One of the purposes of this study is to provide the results for the simulation
codes of subthreshold kaon production in heavy ion collisions. This is the
first, consistent study of the elementary kaon production reactions including
both and () collisions on the same footing.
Comparisons are made between the calculated results and the existing
semi-empirical parametrizations which are widely used for the simulation codes,
as well as the experimental data.Comment: 10 pages with 5 postscript figures, Latex, revised version for
publication in Phys. Lett.
Algebraic totality, towards completeness
Finiteness spaces constitute a categorical model of Linear Logic (LL) whose
objects can be seen as linearly topologised spaces, (a class of topological
vector spaces introduced by Lefschetz in 1942) and morphisms as continuous
linear maps. First, we recall definitions of finiteness spaces and describe
their basic properties deduced from the general theory of linearly topologised
spaces. Then we give an interpretation of LL based on linear algebra. Second,
thanks to separation properties, we can introduce an algebraic notion of
totality candidate in the framework of linearly topologised spaces: a totality
candidate is a closed affine subspace which does not contain 0. We show that
finiteness spaces with totality candidates constitute a model of classical LL.
Finally, we give a barycentric simply typed lambda-calculus, with booleans
and a conditional operator, which can be interpreted in this
model. We prove completeness at type for
every n by an algebraic method
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