885 resultados para PARTICLE CREATION


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The large hadron collider constructed at the European organization for nuclear research, CERN, is the world’s largest single measuring instrument ever built, and also currently the most powerful particle accelerator that exists. The large hadron collider includes six different experiment stations, one of which is called the compact muon solenoid, or the CMS. The main purpose of the CMS is to track and study residue particles from proton-proton collisions. The primary detectors utilized in the CMS are resistive plate chambers (RPCs). To obtain data from these detectors, a link system has been designed. The main idea of the link system is to receive data from the detector front-end electronics in parallel form, and to transmit it onwards in serial form, via an optical fiber. The system is mostly ready and in place. However, a problem has occurred with innermost RPC detectors, located in sector labeled RE1/1; transmission lines for parallel data suffer from signal integrity issues over long distances. As a solution to this, a new version of the link system has been devised, a one that fits in smaller space and can be located within the CMS, closer to the detectors. This RE1/1 link system has been so far completed only partially, with just the mechanical design and casing being done. In this thesis, link system electronics for RE1/1 sector has been designed, by modifying the existing link system concept to better meet the requirements of the RE1/1 sector. In addition to completion of the prototype of the RE1/1 link system electronics, some testing for the system has also been done, to ensure functionality of the design.

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We analyze the influence of the single-particle structure on the neutron density distribution and the neutron skin in Ca, Ni, Zr, Sn, and Pb isotopes. The nucleon density distributions are calculated in the Hartree-Fock+BCS approach with the SLy4 Skyrme force. A close correlation is found between the quantum numbers of the valence neutrons and the changes in the position and the diffuseness of the nuclear surface, which in turn affect the neutron skin thickness. Neutrons in the valence orbitals with low principal quantum number and high angular momentum mainly displace the position of the neutron surface outwards, while neutrons with high principal quantum number and low angular momentum basically increase the diffuseness of the neutron surface. The impact of the valence shell neutrons on the tail of the neutron density distribution is discussed.

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In this paper we seek to verify the hypothesis that trust and cooperation between individuals, and between them and public institutions, can encourage technological innovation and the adoption of knowledge. Additionally, we test the extent to which the interaction of social capital with human capital and R&D expenditures improve their effect on a region’s ability to innovate. Our empirical evidence is taken from the Spanish regions and employs a knowledge production function and longitudinal count data models. Our results suggest that social capital correlates positively with innovation. Further, our analysis reveals a powerful interaction between human and social capital in the production of knowledge, whilst the complementarity with R&D efforts would seem less clear.

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Late on 2011 November 3, STEREO-A, STEREO-B, MESSENGER, and near-Earth spacecraft observed an energetic particle flux enhancement. Based on the analysis of in situ plasma and particle observations, their correlation with remote sensing observations, and an interplanetary transport model, we conclude that the particle increases observed at multiple locations had a common single source active region and the energetic particles filled a very broad region around the Sun. The active region was located at the solar backside (as seen from Earth) and was the source of a large flare, a fast and wide coronal mass ejection, and an EIT wave, accompanied by type II and type III radio-emission. In contrast to previous solar energetic particle events showing broad longitudinal spread, this event showed clear particle anisotropies at three widely separated observation points at 1AU, suggesting direct particle injection close to the magnetic footpoint of each spacecraft, lasting for several hours.We discuss these observations and the possible scenarios explaining the extremely broad particle spread for this event.

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In the last two decades of studying the Solar Energetic Particle (SEP) phenomenon, intensive emphasis has been put on how and when and where these SEPs are injected into interplanetary space. It is well known that SEPs are related to solar flares and CMEs. However, the role of each in the acceleration of SEPs has been under debate since the major role was taken from flares ascribed to CMEs step by step after the skylab mission, which started the era of CME spaceborn observations. Since then, the shock wave generated by powerful CMEs in between 2-5 solar radii is considered the major accelerator. The current paradigm interprets the prolonged proton intensity-time profile in gradual SEP events as a direct effect of accelerated SEPs by shock wave propagating in the interplanetary medium. Thus the powerful CME is thought of as a starter for the acceleration and its shock wave as a continuing accelerator to result in such an intensity-time profile. Generally it is believed that a single powerful CME which might or might not be associated with a flare is always the reason behind such gradual events.

In this work we use the Energetic and Relativistic Nucleus and Electrons ERNE instrument on board Solar and Heliospheric Observatory SOHO to present an empirical study to show the possibility of multiple accelerations in SEP events. In the beginning we found 18 double-peaked SEP events by examining 88 SEP events. The peaks in the intensity-time profile were separated by 3-24 hours. We divided the SEP events according to possible multiple acceleration into four groups and in one of these groups we find evidence for multiple acceleration in velocity dispersion and change in the abundance ratio associated at transition to the second peak. Then we explored the intensity-time profiles of all SEP events during solar cycle 23 and found that most of the SEP events are associated with multiple eruptions at the Sun and we call those events as Multi-Eruption Solar Energetic Particles (MESEP) events. We use the data available by Large Angle and Spectrometric Coronograph LASCO on board SOHO to determine the CME associated with such events and YOHKOH and GOES satellites data to determine the flare associated with such events. We found four types of MESEP according to the appearance of the peaks in the intensity-time profile in large variation of energy levels. We found that it is not possible to determine whether the peaks are related to an eruption at the Sun or not, only by examining the anisotropy flux, He/p ratio and velocity dispersion. Then we chose a rare event in which there is evidence of SEP acceleration from behind previous CME. This work resulted in a conclusion which is inconsistent with the current SEP paradigm. Then we discovered through examining another MESEP event, that energetic particles accelerated by a second CME can penetrate a previous CME-driven decelerating shock. Finally, we report the previous two MESEP events with new two events and find a common basis for second CME SEPs penetrating previous decelerating shocks. This phenomenon is reported for the first time and expected to have significant impact on modification of the current paradigm of the solar energetic particle events.

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The traditional forest industry is a good example of the changing nature of the competitive environment in many industries. Faced with drastic challenges forestindustry companies are forced to search for new value-creating strategies in order to create competitive advantage. The emerging bioenergy business is now offering promising avenues for value creation for both the forest and energy sectors because of their complementary resources and knowledge with respect to bioenergy production from forest-based biomass. The key objective of this dissertation is to examine the sources of sustainable competitive advantage and the value-creation opportunities that are emerging at the intersection between the forest and energy industries. The research topic is considered from different perspectives in order to provide a comprehensive view of the phenomenon. The study discusses the business opportunities that are related to producing bioenergy from forest-based biomass, and sheds light on the greatest challenges and threats influencing the success of collaboration between the forest and energy sectors. In addition, it identifies existing and potential bioenergy actors, and considers the resources and capabilities needed in order to prosper in the bioenergy field. The value-creation perspective is founded on strategic management accounting, the theoretical frameworks are adopted from the field of strategic management, and the future aspect is taken into account through the application of futures studies research methodology. This thesis consists of two parts. The first part provides a synthesis of the overall dissertation, and the second part comprises four complementary research papers. There search setting is explorative in nature, and both qualitative and quantitative research methods are used. As a result, the thesis lays the foundation for non-technological studies on bioenergy. It gives an example of how to study new value-creation opportunities at an industrial intersection, and discusses the main determinants affecting the value-creation process. In order to accomplish these objectives the phenomenon of value creation at the intersection between the forest and energy industries is theorized and connected with the dynamic resource-based view of the firm.

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Aerosol size distributions from 6 to 700 nm were measured simultaneously at an urban background site and a roadside station in Oporto. The particle number concentration was higher at the traffic exposed site, where up to 90% of the size spectrum was dominated by the nucleation mode. Larger aerosol mode diameters were observed in the urban background site possibly due to the coagulation processes or uptake of gases during transport. Factor analysis has shown that road traffic and the neighbour stationary sources localised upwind affect the urban area thought intra-regional pollutant transport.

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This study evaluates the application of an intelligent hybrid system for time-series forecasting of atmospheric pollutant concentration levels. The proposed method consists of an artificial neural network combined with a particle swarm optimization algorithm. The method not only searches relevant time lags for the correct characterization of the time series, but also determines the best neural network architecture. An experimental analysis is performed using four real time series and the results are shown in terms of six performance measures. The experimental results demonstrate that the proposed methodology achieves a fair prediction of the presented pollutant time series by using compact networks.

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This work is devoted to the development of numerical method to deal with convection diffusion dominated problem with reaction term, non - stiff chemical reaction and stiff chemical reaction. The technique is based on the unifying Eulerian - Lagrangian schemes (particle transport method) under the framework of operator splitting method. In the computational domain, the particle set is assigned to solve the convection reaction subproblem along the characteristic curves created by convective velocity. At each time step, convection, diffusion and reaction terms are solved separately by assuming that, each phenomenon occurs separately in a sequential fashion. Moreover, adaptivities and projection techniques are used to add particles in the regions of high gradients (steep fronts) and discontinuities and transfer a solution from particle set onto grid point respectively. The numerical results show that, the particle transport method has improved the solutions of CDR problems. Nevertheless, the method is time consumer when compared with other classical technique e.g., method of lines. Apart from this advantage, the particle transport method can be used to simulate problems that involve movingsteep/smooth fronts such as separation of two or more elements in the system.

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Increasing usage of Web Services has been result of efforts to automate Web Services discovery and interoperability. The Semantic Web Service descriptions create basis for automatic Web Service information management tasks such as discovery and interoperability. The discussion of opportunities enabled by service descriptions have arisen in recent years. The end user has been considered only as a consumer of services and information sharing occurred from one service provider to public in service distribution. The social networking has changed the nature of services. The end user cannot be seen anymore only as service consumer, because by enabling semantically rich environment and right tools, the end user will be in the future the producer of services. This study investigates the ways to provide for end users the empowerment to create service descriptions on mobile device. Special focus is given to the changed role of the end user in service creation. In addition, the Web Services technologies are presented as well as different Semantic Web Service description approaches are compared. The main focus in the study is to investigate tools and techniques to enable service description creation and semantic information management on mobile device.

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The aim of the research was to create a comprehensive city branding process. This was done by identifying the key target groups of the city and considering them in the city branding process. Also key stakeholders were identified and taken into consideration when creating the branding process. As an empirical study, three first stages of the city branding process were implemented for the city of Lappeenranta having "students" as the case target group. An interview with the city officials was conducted, as well as a student survey on the current city image of Lappeenranta. Quantitative research methods were used to analyze the results of the survey. A comprehensive city branding process with eight stages was created in the research. Target groups were considered in the process by identifying the target group dependent stages. The empirical study revealed that the current city image held by the students consists of six dimensions. These dimensions were analyzed from the viewpoint of Lappeenranta with the help of an importance performance analysis.

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In summary the main findings of the study are that there seems to be is no universal definition of value in the context of industrial relationships, but a notion that it is context-, time-, and actor dependent. Value co-creation is a suitable concept in the context of buyerseller relationships. The evolution of a relationship from a transactional to a partnership is long and eventful - a process where the outcome is impossible to estimate in advance. The process is filled with differenttypes of events and also conflicts, which as a matter of fact can be seen as constructive forces in relationship development. The perceived value of a relationship is an antecedent to pursuing a high-involvement strategy; once a partnership exists, the value co-creation potential is realizable through exploiting interdependencies. Those interdependencies are the trigger for value co-creation potential. The value cocreation potential is realized though different processes of value co-creation either to achieve efficiency in exchange or effective use of resources. The logic of buyer-seller partnerships is to create and exploit interdependencies in order to create both efficiency and effective use of resources. (Summary of main findings p. 176)

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New luminometric particle-based methods were developed to quantify protein and to count cells. The developed methods rely on the interaction of the sample with nano- or microparticles and different principles of detection. In fluorescence quenching, timeresolved luminescence resonance energy transfer (TR-LRET), and two-photon excitation fluorescence (TPX) methods, the sample prevents the adsorption of labeled protein to the particles. Depending on the system, the addition of the analyte increases or decreases the luminescence. In the dissociation method, the adsorbed protein protects the Eu(III) chelate on the surface of the particles from dissociation at a low pH. The experimental setups are user-friendly and rapid and do not require hazardous test compounds and elevated temperatures. The sensitivity of the quantification of protein (from 40 to 500 pg bovine serum albumin in a sample) was 20-500-fold better than in most sensitive commercial methods. The quenching method exhibited low protein-to-protein variability and the dissociation method insensitivity to the assay contaminants commonly found in biological samples. Less than ten eukaryotic cells were detected and quantified with all the developed methods under optimized assay conditions. Furthermore, two applications, the method for detection of the aggregation of protein and the cell viability test, were developed by utilizing the TR-LRET method. The detection of the aggregation of protein was allowed at a more than 10,000 times lower concentration, 30 μg/L, compared to the known methods of UV240 absorbance and dynamic light scattering. The TR-LRET method was combined with a nucleic acid assay with cell-impermeable dye to measure the percentage of dead cells in a single tube test with cell counts below 1000 cells/tube.