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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Integration of solar and wind power at Lillgrundwind farm. : Wind turbine shadow effect on solar farm atLillgrund wind farm.

Al-Mimar, Samer January 2015 (has links)
The supply of energy is a key factor in modern societies. As the old fossil sources for energy are dwindling, conflicts arise between competing nations and regions. Fossil energy sources also contribute to the pollution of the environment and emission of greenhouse gases. With renewable energy sources many of these drawbacks with fossil fuels can be eliminated as the energy will be readily available for all without cost or environmental impact. Combining the renewable energy sources will be very effective, particularly in commercial areas where lake of electricity is high. The cost of combining onshore wind and solar power plant is affordable. Furthermore there is no power failure or load shedding situation at any times. When it is manufactured in a large scale, cost of this integrated natural resources power generation system is affordable. Moreover there is no power failure or load shedding situation at any times. Therefore, it is the most reliable renewable power or electricity resources with less spending and highly effective production. ref [1]. The thesis work would take planning of offshore renewable plant (Lillgrund) with considering the resources of renewable power. The study would take in account combining the Lillgrund wind farm with solar system and take close look into the advantage and disadvantage of combining the renewable resources together and figure out if such station can work in proper way and provide sufficient power production. The study would take in account the effect of each resource on other resource, also calculations would be done. The study site is Lillgrund in south of Sweden. The Lillgrund wind farm is the most important offshore wind power plant installed in Sweden with a total capacity of 110 MW, corresponding to 48 turbines. ref [2].
2

Binaural Beamforming Robust to Errors in Direction of Arrival Estimates

Khayeri, Parinaz January 2016 (has links)
Binaural beamforming technology, which is based on the auditory perception of both ears, uses a wireless data connection to exchange data between the right-side and the left-side hearing aids. Over the years, several multichannel speech enhancement algorithms have been used in the hearing aid industry. For example, beamforming algorithms work by keeping a target signal undistorted while attenuating the noise fields (such as diffuse noise or white noise) and the interferers from different directions. Fixed and adaptive algorithms of this nature have been under active investigation by the hearing aid industry. Although binaural beamforming hearing aids designs have shown better performance than single-channel based hearing aids or bilateral hearing aids, the performance of binaural beamforming still suffers from errors in the direction of arrival estimates, i.e., errors which occur when the right set of steering vectors is used in a beamformer design but the target signal source is not located at the direction considered in the design. Therefore, this thesis is devoted to find and propose structures showing more robustness to errors in the direction of arrival estimates. The focus is mainly on the Generalized Sidelobe Canceller (GSC) structure and several binaural beamforming algorithms and configurations are proposed in this thesis as alternatives for the fixed beamformer and blocking matrix units of the GSC. The proposed algorithms show promise of providing wider notch and/or wider beam possibilities, as well as providing greater noise reduction and superior adaptive null positioning capabilities. The algorithms proposed in this thesis were simulated in MATLAB using recorded signals and data provided by a hearing aid firm, to assess their utility for improving hearing aid performance. The results demonstrated a superiority over algorithms currently in use in industry.
3

Determinação da reatividade do veneno queimável de Alsub(2)Osub(3)-Bsub(4)C em função da sua concentração no reator IPEN/MB-01

GIADA, MARINO R. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:51:05Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:29Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
4

Determinação da reatividade do veneno queimável de Alsub(2)Osub(3)-Bsub(4)C em função da sua concentração no reator IPEN/MB-01

GIADA, MARINO R. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:51:05Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:29Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
5

Vliv zastínění na parametry solárních modulů / Shadow effect on solar systems characteristic

Dus, Ondřej January 2008 (has links)
This work deals with study of shadow effect on solar system characteristic. The general aim is to design and create solar module for study of shadow effect and measurement under solar simulator.
6

Revisiting the Paleogene Climate Pattern of East Asia: A Synthetic Review

Quan, Cheng, Liu, Zhonghui, Utescher, Torsten, Jin, Jianhua, Shu, Junwu, Li, Yongxiang, Liu, Yu Sheng (Christopher) 01 December 2014 (has links)
East Asian Paleogene climates have long been regarded as controlled by the planetary wind system, which might result in a climate pattern with three latitudinally distributed zones. Two humid zones located separately in the north and south were lithologically designated by coals and oil shales, while an arid zone in the middle was represented by red beds and evaporites. Because the middle arid zone was located along ~. 30° N paleolatitude, its presence had been further linked with a then subtropical high. However, this long-standing model has recently been challenged by growing evidence from petrology, sedimentology, paleontology, paleobiogeography, paleoclimatology, and climate modeling. Here we review the primary data from these disciplines and reinterpret their climate significances to revisit the East Asian climate pattern during the Paleogene. Petrologically, while the occurrence of coals and/or oil shales is accepted as an indicator for overall humid climates, that of red beds and/or evaporites is highly equivocal to exclusively indicate perennial arid climates unless their origins are carefully investigated. In reality, generic red beds merely represent an oxidizing environment, not essentially associated with a single specific climate type. Meanwhile evaporites, although typically precipitated in arid environments, may be deposited in either perennial dry or seasonal/monsoonal climates. There is no solid evidence so far to convincingly support that the landscape of the so-called middle arid zone was dominated by desert and/or steppe under a then subtropical high during most of the Paleogene. The plant function type study additionally suggests that the "middle arid zone" appears to be lack of xerophytic vegetation, even though some xerophytic or sclerophyllous plant taxa did sporadically occur. Interestingly, paleozoological data show that the Paleogene mammalian faunas were somewhat equably distributed over East Asia, strongly suggesting the evident absence of a critical biogeographical or climatic barrier stretched across the "middle arid zone" as the planetary wind model implied. In contrast to the planetary wind model, monsoonal or monsoon-like Paleogene climates have been broadly reported from the northern, middle, and southern East Asia, as well as adjacent regions of Russia and Kazakhstan. If only the indicators for humid climates are considered, simply due to the uncertainty of those for perennial arid climates, East Asia must have had a relatively dry region in the continental interior during the late Eocene to Oligocene transition, likely caused by the continentality and/or the rain shadow effect along with the global cooling. The monsoonal interpretation is highly in agreement with the evidence from floras, faunas, basin analyses, and modeling experiments, and well explicates the Paleogene climate distribution and seasonal dynamics of East Asia. However, further studies will be largely needed to verify whether, uniformly according to the modern criteria, the Paleogene climates of the East Asia interior can be accurately attributed to the arid category.
7

Statistical methods for assessing and managing wild populations

Hoyle, Simon David January 2005 (has links)
This thesis is presented as a collection of five papers and one report, each of which has been either published after peer review or submitted for publication. It covers a broad range of applied statistical methods, from deterministic modelling to integrated Bayesian modelling using MCMC, via bootstrapping and stochastic simulation. It also covers a broad range of subjects, from analysis of recreational fishing diaries, to genetic mark recapture for wombats. However, it focuses on practical applications of statistics to the management of wild populations. The first chapter (Hoyle and Jellyman 2002, published in Marine and Freshwater Research) applies a simple deterministic yield per recruit model to a fishery management problem: possible overexploitation of the New Zealand longfin eel. The chapter has significant implications for longfin eel fishery management. The second chapter (Hoyle and Cameron 2003, published in Fisheries Management and Ecology) focuses on uncertainty in the classical paradigm, by investigating the best way to estimate bootstrap confidence limits on recreational harvest and catch rate using catch diary data. The third chapter (Hoyle et al., in press with Molecular Ecology Notes) takes a different path by looking at genetic mark-recapture in a fisheries management context. Genetic mark-recapture was developed for wildlife abundance estimation but has not previously been applied to fish harvest rate estimation. The fourth chapter (Hoyle and Banks, submitted) addresses genetic mark-recapture, but in the wildlife context for estimates of abundance rather than harvest rate. Our approach uses individual-based modeling and Bayesian analysis to investigate the effect of shadows on abundance estimates and confidence intervals, and to provide guidelines for developing sets of loci for populations of different sizes and levels of relatedness. The fifth chapter (Hoyle and Maunder 2004, Animal Biodiversity and Conservation) applies integrated analysis techniques developed in fisheries to the modeling of protected species population dynamics - specifically the north-eastern spotted dolphin, Stenella attenuata. It combines data from a number of different sources in a single statistical model, and estimates parameters using both maximum likelihood and Bayesian MCMC. The sixth chapter (Hoyle 2002, peer reviewed and published as Queensland Department of Primary Industries Information Series) results directly from a pressing management issue: developing new management procedures for the Queensland east coast Spanish mackerel fishery. It uses an existing stock assessment as a starting point for an integrated Bayesian management strategy evaluation. Possibilities for further research have been identified within the subject areas of each chapter, both within the chapters and in the final discussion chapter.
8

Quantifying the Shadow Effect between Offshore Wind Farms with Idealized Mesoscale Models and Observed Wind Data

Werner, David January 2016 (has links)
Two post processing methods for quantifying the shadow effect of the offshore wind farm Princes Amalia (PA) onto Egmond aan Zee (OWEZ) wind farm are analyzed and benchmarked. The first method is the author’s proposed shadow effect determination method (SEDM), which quantifies an offshore wind farm’s shadow effect based on mesoscale WRF (Weather Research Forecast) idealized modeling and the observed frequency of the analyzed site’s wind conditions. The Fitch turbine parametrization scheme and Mellor-Yamada-Nakanishi-Niino (MYNN) surface layer and planetary boundary layer (PBL) schemes were used to simulate the wind farm’s interactions, based on site conditions. The proposed physical downscaling method (SEDM) uses filtered simulated atmospheric stability and wind speed conditions, in order to calculate the percent wind speed deficit downstream of PA, with regard, first, to observed wind speed frequency and, secondly, to wind speed and corresponding atmospheric stability regimes. Then a statistical downscaling method, based on the established Analog Ensemble (AnEn) technique, developed by Luca Delle Monache et al. (2011) was employed to verify the results from the first method. This method runs a post processing algorithm using the weighted average of the observations that were verified when the 15 best analogs were valid. Observed wind speed data at 10 m and 50 m height was used as Numerical Weather Prediction (NWP) input data and fit to observed time series data. From this, wind speeds at 116 m were extrapolated, in order to estimate the reconstructed atmospheric stability. The two methods were benchmarked and shadow effects were quantified in the range of 7.53% - 22.92% for the SEDM and within an 80% confidence interval of 0.23% -1.83% for the statistical downscaling method. Given the physical method’s exceedance of this confidence interval, WRF idealized modeling proves itself as a consistent means of quantifying an offshore wind farm’s wake, as demonstrated by comparable studies, however inaccurate when benchmarked to statistical modelling methods that use observed wind speed data to recreate atmospheric conditions. / Wake Research Group
9

Bilateral processing benefit in sequentially implanted adult cochlear implant users

Oosthuizen, Ilze 09 December 2011 (has links)
Bilateral cochlear implantation is accepted medical practice since 2008 in clinically suitable adults and children to enhance bilateral processing benefits. Bilateral implantation may lead to the restoration of some bilateral hearing advantages, such as improved speech recognition in noise, localisation, head shadow effect, summation, and squelch. The majority of the advantages stated in literature, though, are characteristic of the simultaneously implanted cochlear implant population. Simultaneous implantation is not yet a reality in South Africa due to funding constraints, therefore determining the bilateral processing abilities in sequentially implanted adults is essential. Determining bilateral processing benefits achievable with sequential implantation could result in evidence-based recommendations in terms of candidacy considerations, surgery protocols, motivations for medical aid funding for simultaneous cochlear implantation, and relevant measures to determine the bilateral processing benefit attainable. Furthermore, it might enhance audiologists‟ insight regarding post-implantation performance of sequentially implanted patients and enable them to counsel prospective candidates realistically. The aaim of this study was to determine the bilateral benefit attained by sequentially implanted adults. A quantitative, cross-sectional research approach was followed in a one group post-test-only exploratory research design. A purposive convenient sampling method with specified selection criteria was used to select 11 adult clients of an established cochlear implant programme in Pretoria. Tests of sound localisation in the horizontal plane and speech perception in noise were performed. During the test of sound localisation, performance with only the first or only the second implant was found to be very similar. For the majority of participants the second cochlear implant (CI 2) was the superior performing implant during xviii speech perception in noise testing, in spatially separated speech and noise conditions where noise was directed to the first implant, as well as in spatially coincident speech and noise. A statistical significant bilateral benefit (p < 0.05) was attained by sequentially implanted adults for sound localisation. A bilateral benefit for speech perception in noise was observed when noise was directed to the first implant and in the diotic listening condition with average benefits of 1.69 dB and 0.78 dB, respectively. It was not statistically significant (p > 0.05), however, and was smaller than bilateral benefit values achieved by simultaneously implanted adults in previous studies. The head shadow effect at 180° was found to be the strongest and most robust bilateral spatial benefit. Squelch and summation benefit values ranged from negative values to 2 dB and 6 dB, respectively. This corresponded with values found in previous studies. The improvement in speech perception in spatially distinct speech and noise from adding the ear with a better SNR (signal to noise ratio) indicated that the contribution of CI 2 seems to be greater than that of CI 1 for bilateral spatial benefit. It can be concluded that adults with sequential implants may achieve some extent of bilateral benefit even with many years of unilateral implant use, when speech processors differ, when the second implant is done ≥ 10 years after the first implant, and in cases of prelingual deafness. A key benefit of sequential implantation appears to be related to the advantage of having hearing on both sides so that the ear with the more favourable environmental signalto-noise ratio is always available. AFRIKAANS : Bilaterale kogleêre inplanting is sedert 2008 aanvaarde mediese praktyk vir klinies geskikte volwassenes en kinders, ten einde bilaterale prosesseringsvoordeel te verhoog. Bilaterale inplanting kan lei tot die herstel van sommige van die voordele van bilaterale gehoor, soos verbeterde spraakherkenning in lawaai, klanklokalisering, die kopskadueffek, sommering en selektiewe onderdrukking (“squelch”). Die meeste van die voordele wat in die literatuur bespreek word, is egter kenmerkend van dié persone by wie twee kogleêre inplantings gelyktydig gedoen is. Gelyktydige inplanting is as gevolg van beperkte befondsing nog nie in Suid-Afrika 'n werklikheid nie, daarom is dit noodsaaklik om te bepaal watter bilaterale prosesseringsvoordele by opeenvolgend-geïnplanteerde volwassenes voorkom. Die bepaling van watter bilaterale prosesseringsvoordele met opeenvolgende inplanting bereik kan word, sou kon lei tot getuienis-gebaseerde aanbevelings met betrekking tot besluite oor die geskiktheid van kandidate, protokol vir sjirurgie, motiverings vir die befondsing van gelyktydige kogleêre inplantings deur mediese voorsorgfondse, en toepaslike maatstawwe om te bepaal watter mate van bilaterale prosesseringsvoordeel haalbaar sou wees. Dit sou verder oudioloë se insig kon verbreed met betrekking tot die na-operatiewe prestasie van opeenvolgend-geïnplanteerde persone en hulle sodoende in staat stel om voornemende kandidate van realistiese raad te bedien. Die doel van hierdie studie was om te bepaal wat die bilaterale prosesseringsvoordele is wat deur opeenvolgend-geïnplanteerde volwassenes verkry kan word. 'n Kwantitatiewe navorsingsbenadering met 'n dwarsprofiel van „n enkelgroep is gevolg, met 'n post-toets verkennende navorsingsontwerp. 'n Doelgerigte gerieflikheidssteekproef met 'n gespesifiseerde seleksiekriteria is gebruik om 11 volwasse kliënte van 'n gevestigde kogleêre inplantprogram in Pretoria te selekteer. Klanklokalisering in die horisontale vlak en die waarneming van spraak in lawaai is getoets. Tydens die toets vir klanklokalisering is gevind dat prestasie met slegs die eerste of slegs die tweede inplanting soortgelyk was. Vir die meeste deelnemers aan die studie het die tweede kogleêre inplanting (KI 2) die beste prestasie gelewer tydens spraakwaarneming in lawaai, in omstandighede waar spraak en lawaai ruimtelik geskei is en die lawaai op die eerste inplanting gerig is, asook in omstandighede waar spraak en lawaai ruimtelik saamvoorkomend aangebied is. 'n Statisties beduidende bilaterale voordeel (p < 0.05) is deur opeenvolgend-geïnplanteerde volwassenes vir klanklokalisering behaal. 'n Bilaterale voordeel vir spraakwaarneming in lawaai is waargeneem waar lawaai op die eerste inplanting gerig is en ook in diotiese luistertoestande, met 'n gemiddelde voordeel van 1.69 dB en 0.78 dB, onderskeidelik. Dit was egter nie statisties beduidend nie en was ook kleiner as die bilaterale voordeelwaardes wat in vorige studies deur gelyktydig-geïnplanteerde volwassenes behaal is. Die kopskadu-effek by 180° was die sterkste en mees robuuste bilaterale ruimtelike voordeel. Voordeelwaardes vir selektiewe onderdrukking en sommering het gewissel van negatiewe waardes tot 2 dB en 6 dB onderskeidelik. Dit stem ooreen met waardes wat in vorige studies gevind is. Die verbetering in spraakwaarneming in ruimtelik geskeide spraak en lawaai wat verkry is deur die oor met 'n beter STR (sein-tot-ruis ratio) by te voeg, het daarop gedui dat die bydrae van KI 2 tot bilaterale ruimtelike voordeel waarskynlik groter as die bydrae van KI 1 is. Die gevolgtrekking kan gemaak word dat volwassenes met opeenvolgende inplantings 'n mate van bilaterale voordeel verkry selfs na vele jare van unilaterale inplantingsgebruik, wanneer die spraakprosesseerders in die twee inplantings van mekaar verskil, wanneer die tweede inplanting ≥ 10 jaar na die eerste plaasvind, en in gevalle van prelinguale doofheid. 'n Sleutelvoordeel van opeenvolgende inplanting hou klaarblyklik verband met die voordeel van gehoor aan albei kante te hê sodat die oor met die gunstigste sein-tot-lawaai ratio altyd beskikbaar is. / Dissertation (MCommunication Pathology)--University of Pretoria, 2011. / Speech-Language Pathology and Audiology / Unrestricted
10

Whole Teachers: A Holistic Education Perspective on Krishnamurti‘s Educational Philosophy

Rathnam, Anbananthan 09 August 2013 (has links)
The purpose of this qualitative research study, which utilizes a phenomenological inquiry method, is to inquire into the awareness of what it means to be a whole teacher from the perspective of the philosophy of Jiddu Krishnamurti, a philosopher/spiritual teacher. Four participants (teachers) were interviewed from the Oak Grove School, an alternative, holistic school founded by Krishnamurti in 1974. This inquiry probed into teachers’ thinking, teachers’ lives, teachers’ inner lives, teachers’ contemplative practices, teachers’ calling/vocation and teachers’ pedagogy. The findings of this inquiry reveal the awareness that exists among the participants with regards to their understanding of Krishnamurti’s educational philosophy and the way in which this philosophy has shaped their lives and the lives of their students (both implicit- ly and explicitly) The findings from this research further show that Krishnamurti’s philosophy has certainly had an impact on the participants’ wholeness. Krishnamurti was never interested in imposing his philosophy on the teachers to think in a narrow groove. Rather, he challenged them to arrive at wholeness or a holistic approach towards living by their own volition, by putting aside all philosophy, including his own. This research points towards the possible ways in which wholeness can be developed using: Innate wisdom (teachers’ inner life, teachers’ calling); wisdom gained through experiencing life (teachers’ life, teachers’ thinking); wisdom gained through their teaching experience (teachers’ pedagogy) and wisdom gained through practices that bring harmony to the mind, body and spirit (teachers’ contemplative approaches). An experiential model titled, The Flower Model: An Experiential Metaphor – which integrates the three stages of awareness – was developed using Krishnamurti’s approach towards wholeness. This model can be used to guide teachers with their respective psychological conditionings that reside or exist in their thinking, lives, inner lives, contemplative practices, vocation and pedagogy/curriculum design.

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