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Structural Analysis and Electrochemical Properties of Bimetallic Palladium–Platinum Aerogels Prepared by a Two‐Step Gelation ProcessOezaslan, Mehtap, Herrmann, Anne-Kristin, Werheid, Matthias, Frenkel, Anatoly, Nachtegaal, Maarten, Dosche, Carsten, Laugier Bonnaud, Celine, Ceren Yilmaz, Hale, Kühn, Laura, Rhiel, Erhard, Gaponik, Nikolai, Eychmüller, Alexander, Schmidt, Thomas Justus 19 July 2018 (has links) (PDF)
Multi-metallic aerogels have emerged as a promising unsupported, high surface area-based metal material for different applications in heterogeneous catalysis and electrochemistry. The fabrication of these multi-metallic aerogels is based on a complex gelation process which is characterized by controlled aggregation of metallic nanoparticles to form a macroscopic network structure in aqueous solution. However, achieving structural homogeneity of the multi-metallic aerogels in terms of diameter of the nanochains and chemical composition at the nano- as well as at the macro-scale is still a great challenge.
In this paper, we show the characterization of two Pd-Pt aerogels prepared by the two-step gelation method. The structural homogeneity and chemical distribution of both metals (Pd and Pt) inside the aerogels were analyzed using high-resolution (scanning) transmission microscopy (HR(S)TEM), energy-dispersive X-ray spectroscopy (EDX), extended X-ray absorption fine structure (EXAFS) spectroscopy, and cyclic voltammetry. Based on the microscopic and spectroscopic results, the Pd-Pt aerogels show the presence of Pd/Pt-rich domains inside the long-range framework. It is evident that the initial monometallic features dominate over alloying during the gelation process. Although the same synthetic approach for Pd-Pt aerogels with different atomic ratios was used, we observed that the sizes of these monometallic domains strongly varied between the Pd-rich and Pt-rich aerogels. For instance, the Pd-rich aerogels showed larger clusters with a size range from few nanometers up to several tens of nanometers, while the dimension of the clusters of the Pt-rich aerogels varies from the sub-nanometers to a few nanometers. The presence of the metal clusters strongly influenced the electrochemical robustness of these Pd-Pt aerogels. Electrochemical durability investigations revealed that the aerogels with a high content of Pd are less stable due to the gradual dissolution of the less noble metal in particular inside the Pd-rich domains. A better chemical and structural homogeneity might improve the life-time of the Pd-Pt aerogels under electrochemical conditions.
In this work, we provide a better understanding about the structure and chemical distribution of the bimetallic aerogel framework prepared by the two step gelation process.
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Uniformidade de mistura das rações e seu efeito no desempenho de frangos de corte / Feed mix uniformity and its effect on performance of broilersRocha, Alexandre Gomes da 23 June 2014 (has links)
The aim of this study was to compare different indicators used on quality control to access the feed mixture uniformity, and were made correlation analysis between the analytical methods used to measure de indicators employed. On a following step, it was evaluated the effect of lack of feed mixture homogeneity on performance of broilers. In the first step, after the analysis of feed mixer efficiency, nine indicators of dry mixture efficiency and two for wet mixture were compared. On the mixer efficiency tests were observed inconstant values of coefficient of variation (CV) after the time needed to achieve CV below 5%. On the comparison of the indicators of dry mixture, five of them presented mean coefficients of variation (CVs) less than 5%, and on the wet mixture indicators comparison test one indicator presented this result. On the correlation analysis, no expressive results were observed, and then the use of alternative methods on the analysis of the indicators can t be justified by this means. On the second step, broilers were reared in four productive phases, with diets with CVs between 5.35 e 49.48%, and were evaluated performance and uniformity of weights of these animals. The obtained results showed that the diets with CVs up to 22.63% cause no effects on the performance of broilers with age above than 12 days. The lack of uniformity of the diets with CV up to 49.48%, don t affect the uniformity of weights of broilers during the rearing period and at slaughter. Concluding the study, it was developed a computer system to guide evaluations of mixture efficiency on industrial equipment of feed production. / Objetivou-se comparar diferentes indicadores utilizados no controle de qualidade para a determinação da eficiência de mistura de rações, e realizaram-se análises de correlações entre os métodos analíticos utilizados na mensuração dos indicadores empregados. Em etapa complementar, avaliou-se o efeito da falta de homogeneidade de mistura das rações sobre o desempenho de frangos de corte. Na primeira etapa, após análise da eficiência do equipamento de mistura foram comparados nove indicadores de eficiência de mistura seca e dois de mistura úmida. Nos testes de eficiência de mistura constataram-se valores inconstantes do coeficiente de variação (CV) após o tempo necessário para atingir CV inferior a 5%. Na comparação de indicadores de mistura seca, cinco destes apresentaram coeficientes de variação (CVs) médios menores do que 5% e no teste comparação de indicadores de mistura úmida, com um dos indicadores obteve-se este resultado. Nas análises de correlações não se observaram valores expressivos que justifiquem o emprego de métodos alternativos de análises dos indicadores. Na segunda etapa, frangos de corte foram criados em quatro fases produtivas, com rações com CVs entre 5,35 e 49,48%, e foram avaliados o desempenho zootécnico e a uniformidade dos pesos destes animais. Os resultados obtidos indicaram que rações com CVs até 22,63%, não causam efeitos sobre o desempenho zootécnico dos frangos de corte com idade superior a 12 dias. A falta de uniformidade das rações, com CV até 49,48%, não afeta a uniformidade dos pesos dos frangos de corte durante o crescimento e no momento do abate. Concluindo o estudo, foi desenvolvido um sistema computacional orientativo para avaliações de eficiência de mistura em equipamentos industriais de produção de rações.
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Camera-based photoplethysmography in an intraoperative settingTrumpp, Alexander, Lohr, Johannes, Wedekind, Daniel, Schmidt, Martin, Burghardt, Matthias, Heller, Axel R., Malberg, Hagen, Zaunseder, Sebastian 11 June 2018 (has links)
Background
Camera-based photoplethysmography (cbPPG) is a measurement technique which enables remote vital sign monitoring by using cameras. To obtain valid plethysmograms, proper regions of interest (ROIs) have to be selected in the video data. Most automated selection methods rely on specific spatial or temporal features limiting a broader application. In this work, we present a new method which overcomes those drawbacks and, therefore, allows cbPPG to be applied in an intraoperative environment.
Methods
We recorded 41 patients during surgery using an RGB and a near-infrared (NIR) camera. A Bayesian skin classifier was employed to detect suitable regions, and a level set segmentation approach to define and track ROIs based on spatial homogeneity.
Results
The results show stable and homogeneously illuminated ROIs. We further evaluated their quality with regards to extracted cbPPG signals. The green channel provided the best results where heart rates could be correctly estimated in 95.6% of cases. The NIR channel yielded the highest contribution in compensating false estimations.
Conclusions
The proposed method proved that cbPPG is applicable in intraoperative environments. It can be easily transferred to other settings regardless of which body site is considered.
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Advanced methods and models in uncertainty for the order promising process in supply chain characterized by the lack of homogeneity in productGrillo Espinoza, Hanzel 22 September 2019 (has links)
The Lack of Homogeneity in the Product (LHP) appears in productive processes with raw materials, which directly stem from nature and/or production processes with operations that confer heterogeneity to the characteristics of the outputs obtained, even when the inputs used are homogeneous. LHP appears in different sectors such as ceramic tile, horticulture, marble, snacks, among others. LHP becomes a managerial problem when customers require to be served with homogeneous product. Supply chains responsible to provide homogeneous product face the need to include classification activities in their productive processes to obtain sub-lots of homogeneous product. Due to the inherent LHP uncertainty, these homogeneous sub-lots will not be known until the product have been produced and classified. An improper management of the LHP can have a very negative impact on the customers' satisfaction due to inconsistencies in the answer to their requirements and also on the Supply Chain's efficiency.
The Order Promising Process (OPP) appears as a key element for properly managing the LHP in order to ensure the matching of uncertain homogeneous supply with customer order proposals. The OPP refers to the set of business activities that are triggered to provide a response to the orders from customers. These activities are related to the acceptance/rejection decision, and to set delivery dates. For supply chains affected by the LHP, the OPP must consider the homogeneity as another requirement in the answer to the orders. Besides, due to the LHP inherent uncertainty, discrepancies between the real and planned homogeneous quantities might provoke that previously committed orders cannot be served. The Shortage Planning (SP) process intends to find alternatives in order to minimise the negative impact on customers and the supply chain.
Considering LHP in the OPP brings a set of new challenging features to be addressed. The conventional approach of assuming homogeneity in the product for the master production schedule (MPS) and the quantities Available-To-Promise (ATP) derived from it is no longer adequate. Instead, both the MPS and ATP should be handled in terms of homogeneous sub-lots. Since the exact quantity of homogeneous product from the planned lots in the MPS is not exactly known until the classification activities have been performed, the ATP also inherits this uncertainty, bringing a new level of complexity. Non-homogeneous product cannot be accumulated in order to fulfil future incoming orders. Even more, if the product handled is perishable, the homogeneity management becomes considerably more complex. This is because the state of the product is dynamic with time and related variables to it, like quality, price, etc., could change with time. This situation could bring unexpected wasting costs apart from the shortages already mentioned. The perishability factor is itself another source of uncertainty associated to the LHP.
This dissertation proposes a conceptual framework and different mathematical programming models and tools, in both deterministic and uncertainty environments, in order to support the OPP and SP under LHP's effect. The aim is to provide a reliable commitment with customer orders looking for a high service level not just in the due date and quantity but also in the homogeneity requirements. The modelling of the characteristics inherent to LHP under deterministic context constitutes itself one of the main contribution of this dissertation. Another novelty consists in the inclusion of uncertainty in the definition of homogeneous sub-lots, their quantities and their dynamic state and value. The uncertainty modelling approach proposed is mainly based on the application of fuzzy set theory and possibility theory.
The proposed mathematical models and tools have been validated in real cases of SC, specifically in the ceramic tile sector for non perishables, and in the fruit sector for perishables. The results show a ... / La Falta de Homogeneidad en el Producto (LHP, por sus siglas del inglés ``Lack of Homogeneity in the Product'') aparece en procesos productivos con materias primas que derivan directamente de la naturaleza y/o procesos de producción con operaciones que confieren heterogeneidad a las características de los productos obtenidos, incluso cuando los insumos utilizados son homogéneos. La LHP aparece en diferentes sectores como la cerámica, horticultura, mármol, snacks, entre otros. Se convierte en un problema gerencial cuando los clientes requieren homogeneidad en el producto y las cadenas de suministro enfrentan la necesidad de incluir actividades de clasificación en sus procesos productivos para obtener sub-lotes de producto homogéneo. Debido a la incertidumbre inherente a la LHP, los sub-lotes homogéneos y su cantidad no serán conocidos hasta que el producto haya sido producido y clasificado. Una gestión inadecuada de la LHP puede tener un impacto muy negativo en la satisfacción de los clientes debido a inconsistencias en la respuesta a sus requerimientos y también en la eficacia de la Cadena de Suministro.
El Proceso de Comprometer de Pedido (OPP, por sus siglas del inglés ``Order Promising Process'') aparece como un elemento clave para gestionar adecuadamente la LHP, con el fin de asegurar la coincidencia entre el suministro incierto de producto homogéneo y las propuestas de pedido del cliente. El OPP se refiere al conjunto de actividades empresariales realizadas para proporcionar una respuesta a las órdenes de los clientes. Estas actividades están relacionadas con las decisiones de aceptación/rechazo, y establecimiento de fechas de entrega para las órdenes del cliente. En las cadenas de suministro afectadas por la LHP, el OPP debe considerar la homogeneidad como otro requisito adicional en la respuesta a los pedidos. Además, debido a la incertidumbre intrínseca de la LHP, las discrepancias entre las cantidades homogéneas reales y planificadas podrían provocar que las órdenes comprometidas anteriormente no puedan ser completadas debido a la escasez de producto. El proceso de planificación de la escasez (SP, por sus siglas del inglés "Shortage Planning") se encarga de encontrar alternativas para minimizar este impacto negativo en los clientes y la cadena de suministro.
Considerar la LHP dentro del OPP implica un conjunto nuevo de características desafiantes que deben ser abordadas. El enfoque convencional de asumir la homogeneidad en el producto para el programa maestro de producción (MPS, por sus siglas del inglés "Master Production Schedule") y las cantidades disponibles a comprometer (ATP, por sus siglas del inglés "Available-To-Promise") derivadas de él, no es adecuado. En cambio, tanto el MPS como el ATP deben manejarse en términos de sub-lotes homogéneos. Dado que la cantidad exacta de producto homogéneo de los lotes previstos en el MPS no se sabe exactamente hasta que se han realizado las actividades de clasificación, el ATP también hereda esta incertidumbre, trayendo un nuevo nivel de complejidad. El producto no homogéneo no se puede acumular para satisfacer futuras órdenes entrantes. Más aún, si el producto manipulado es perecedero, el manejo de la homogeneidad se vuelve mucho más complejo. Esto se debe a que el estado del producto es dinámico en el tiempo, y variables relacionadas como calidad, precio, etc., podrían también cambiar con el tiempo. Esta situación puede provocar costos inesperados de desperdicio aparte de la escasez ya mencionada. El factor de perecedero es en sí mismo otra fuente de incertidumbre asociada a la LHP.
Esta disertación propone un marco conceptual y diferentes modelos y herramientas de programación matemática, tanto en entornos deterministas como de incertidumbre, para apoyar al OPP y SP considerando el efecto de LHP. El objetivo es proporcionar un compromiso fiable con los pedidos de los clientes en busca de un alto nivel de servicio no s / La Falta d'Homogeneïtat en el Producte (LHP, per les seues sigles de l'anglés ''Lack of Homogeneity in the Product'') apareix en processos productius amb matèries primes que deriven directament de la natura i/o processos de producció amb operacions que conferixen heterogeneïtat a les característiques dels productes obtinguts, fins i tot quan les entrades utilitzades són homogènies . La LHP apareix en diferents sectors com la ceràmica, horticultura, marbre, snacks, entre altres. Es convertix en un problema gerencial quan els clients requereixen homogeneïtat en el producte i les cadenes de subministrament enfronten la necessitat d'incloure activitats de classificació en els seus processos productius per a obtindre sublots de producte homogeni. A causa de la incertesa inherent a la LHP, els sublots homogenis i la seua quantitat no seran coneguts fins que el producte haja sigut produït i classificat. Una gestió inadequada de la LHP pot tindre un impacte molt negatiu en la satisfacció dels clients degut a inconsistències en la resposta als seus requeriments i també en l'eficàcia de la Cadena de Subministrament.
El Procés de Comprometre Comandes (OPP, per les seues sigles de l'anglés ''Order Promising Process'') apareix com un element clau per a gestionar adequadament la LHP, a fi d'assegurar la coincidència entre el subministrament incert de producte homogeni i les propostes de comanda del client. L'OPP es refereix al conjunt d'activitats empresarials realitzades per a proporcionar una resposta a les ordres dels clients. Aquestes activitats estan relacionades amb les decisions d'acceptació/rebuig, i establiment de dates de lliurament per a les ordres del client. En les cadenes de subministrament afectades per la LHP, l'OPP ha de considerar l'homogeneïtat com un altre requisit addicional en la resposta a les comandes. A més, a causa de la incertesa intrínseca de la LHP, les discrepàncies entre les quantitats homogènies reals i planificades podrien provocar que les ordres compromeses anteriorment no puguen ser completades a causa de l'escassetat de producte. El procés de planificació de l'escassetat (SP, per les seues sigles de l'anglés "Shortage Planning") s'encarrega de trobar alternatives per a minimitzar aquest impacte negatiu en els clients i en la cadena de subministrament.
Considerar la LHP dins de l'OPP implica un conjunt nou de característiques desafiants que han de ser abordades. L'enfocament convencional d'assumir l'homogeneïtat en el producte per al programa mestre de producció (MPS, per les seues sigles de l'anglés "Master Production Schedule") i les quantitats disponibles a comprometre (ATP, per les seues sigles de l'anglés "Available-To-Promise") derivades d'ell, no és adequat. En canvi, tant el MPS com l'ATP han de manejar-se en termes de sublots homogenis. Atés que la quantitat exacta de producte homogeni dels lots previstos en el MPS no se sap exactament fins que s'han realitzat les activitats de classificació, l'ATP també hereta aquesta incertesa, portant un nou nivell de complexitat. El producte no homogeni no es pot acumular per a satisfer futures ordees entrants. Més encara, si el producte manipulat és perible, el maneig de l'homogeneïtat es torna molt més complex. Açò es deu al fet que l'estat del producte és dinàmic en el temps, i variables relacionades com qualitat, preu, etc., podrien també canviar amb el temps. Aquesta situació pot provocar costos inesperats de rebuig a banda de l'escassetat ja esmentada. El factor de perible és en si mateix un altra font d'incertesa associada a la LHP.
Aquesta dissertació proposa un marc conceptual i diferents models i eines de programació matemàtica, tant en entorns deterministes com d'incertesa, per a recolzar a l'OPP i SP considerant l'efecte de LHP. L'objectiu és proporcionar un compromís fiable amb les comandes dels clients a la recerca d'un alt nivell de servei no sols en la data i la quantitat esperades, s / Grillo Espinoza, H. (2017). Advanced methods and models in uncertainty for the order promising process in supply chain characterized by the lack of homogeneity in product [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/91110 / TESIS
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Hållbarhetsrapportering inom skogsindustrinFöretags homogenitet i rapporterna och dess förändring över tidAndersson, Vilma, Gisslin, Frida January 2021 (has links)
Till följd av en växande medvetenhet om vikten av att agera hållbart, har det allmänna intresset för hållbarhet ökat över tid. Som en effekt av detta har företag drivits till att redovisa sitt arbete med hållbarhetsfrågor och sin påverkan på samhället, denna information sammanställs i så kallade hållbarhetsrapporter. Under år 2016 ändrades årsredovisningslagen (SFS 1995:1554) och kompletterandes med obligatorisk hållbarhetsrapportering för större företag (SFS 2016:947). Syftet med lagen var att ställa tydliga krav på vad en hållbarhetsrapport ska innehålla, vilket kan bidra till att innehållets variation minskar. Denna uppsats tar avstamp i ämnet hållbarhets-rapportering och berör den möjliga homogenitet som kan identifieras i bolags hållbar-hetsrapporter mellan åren 2008. 2015 och 2019. Företagen som uppsatsen utgår ifrån är SCA, Holmen och Sveaskog, vilka alla verkar inom den svenska skogsindustrin. Branschen har en betydande roll för Sveriges ekonomi och industrin har historiskt sett och än idag har en stor miljöpåverkan. Problemet angreps med hjälp av innehållsanalysen, vilken är en form av dokumentanalys som i det här sammanhanget hör till den kvalitativa metodologin. Vid analysen tillämpades teoretiska ramverk i form av legitimitetsskapande och institutionell teori för att stödja tolkningarna. Även ram- och regelverk, samt tidigare forskning inom ämne användes under analysprocessen. Granskningen av hållbarhetsrapporterna är avgränsat till avsnitten om miljömässigt-, socialt- och ekonomiskt ansvar, samt en mer övergripande bild över rapporterna. De teman som speciellt tagits i beaktning samman-ställdes i ett kodningsschema som går att finna i empirikapitlet. Slutsatserna som undersökningen mynnade ut i visar sig vara att företagen i stor utsträckning tycks ta efter varandras sätt att formge hållbarhetsrapporter. Den homogenitet som identifierats utifrån de kategorier som har behandlats i denna uppsats är att företagen över tid valt att sammanfoga sina rapporter, samt att samtliga företag övergått till att applicera GRI standarderna på Core nivå. Hållbarhetsrapporterna har även successivt gått från att vara mer självkritiska, till att bli mindre självkritiska. Vad som också är gemensamt för de olika företagens rapporter är att liknande aktuella samhällsämnen beskrivs, vilket kan förklaras genom företagens syn på legitimitet. / As a result of a growing awareness of the importance of acting sustainably, the general interest in sustainability has increased over time. As an effect of this, companies have been driven to report their work on sustainability issues and its impact on society, this information is compiled in so-called sustainability reports. During 2016, the Annual Accounts Act (SFS 1995: 1554) was amended and supplemented with mandatory sustainability reporting for larger companies (SFS 2016: 947). The purpose of the law was to set clear requirements for what a sustainability report must contain, which can contribute to reducing the variation in the content. This essay is based on the subject of sustainability reporting and possible homogeneity in different companies’ sustainability reports. The companies used as examples are SCA, Holmen and Sveaskog, all of which operate in the Swedish forest industry. The industry can be considered suitable as the forest industry has a significant role for Sweden's economy, at the same time as the industry has historically and even today has a major environmental impact. The problem is tackled with the help of the content analysis, which is a form of document analysis that, in this context, belongs to the qualitative methodology. During the analysis, theoretical frameworks were applied in the form of legitimacy creation and institutional theory to support the interpretations. Frameworks and regulations, as well as previous research in the subject, were also of great importance during the analysis process. The review of the sustainability reports is limited to the sections on environ-mental, social, and economic responsibility, as well as a more comprehensive picture of the reports. The themes that were especially considered were compiled in a coding scheme that can be found at the end of the essay in the form of an appendix. The conclusions that the survey led turned out to be that the companies to a certain extent seem to follow each other's ways of shaping sustainability reports. The homogeneity identified on the basis of the categories addressed in this thesis are that over time, companies have chosen to merge their reports, and that all companies move to applying the GRI standards at Core level. The sustainability reports have also gradually gone from being more self-critical, to becoming less self-critical. What is also common to the various companies 'reports is that similar current social topics are described, which can be explained by the companies' views on legitimacy.
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Rozvoj a využití nedestruktivních zkušebních metod z hlediska soudního inženýrství / Development and use of non-destructive testing methods from the point of view of forensic engineeringBílek, Petr January 2019 (has links)
Concretes reinforced by, using distributed steel reinforcements (fibres) are known as fibre-concrete. In case of disturbances or accidents of concrete structures reinforced with wires, it is necessary to carefully examine the actual implementation of dispersed reinforcement. Fibre concretes belong to modern building materials whose possible applications have not been fully utilized so far. Have been mainly used for floor structures loaded with factory halls and warehouses. Recently, thanks to well-known physical and mechanical properties of fibre-concrete, there were numerous attempts of designers, and namely investors, to utilize this kind of materials for support structures either. Favorable properties of wire-concrete can be utilized if there is a necessity to increase the resistance of concrete to stresses exceeding its strength, cyclic stress or impact stress. Daily practice shows to prove that the applications of fibre-concrete in such structures lead to the economic success. Necessary condition for successful application of steel fiber reinforced concrete in constructions however consists in its uniform dispersion, a homogeneous distribution of the wires throughout the volume of the structure. In case of inappropriate processing and deposition of the mixture during the manufacturing process fiber-concrete structures, the fibers are often unevenly distributed. Wires itself represent unfavourably shaped mixture components and they are extremely deteriorating its workability. A grouping of wires may be encountered as well, which reduces the overall homogeneity and the quality of steel fiber-concrete structures. If the homogeneity of fibre-concrete is not kept, the material possess different properties in various parts of the structure (for example, tensile strength), which can lead to defects in the structure (generation and development of cracks). The relevant lower reliability of the structure which is caused by unequal distribution of fibres (wires) in concrete volume can lead to damage of the property as well as the safety and the human lives can be jeopardized. Hence it is necessary to secure the effective control of the fibre-concrete homogeneity in ready support fibre-concrete structures. Contemporary homogeneity control is still ongoing on fresh blends, but if the fibre-concrete hardened and is a part of the construction, no known reliable methods are currently in available to test the homogeneity of the fibre-concrete on the structure without its destruction. The methods developed to control the concentration of wires in wire-concrete structures are based mostly on magnetic or electromagnetic properties of wires. The thesis deals with the development of the magnetic method in situ using permanent magnets for monitoring the distribution of fibers in hardened steel fiber-concrete structures. The test principle is based on measurements of the changes in magnetic field strength of permanent magnets which are induced by a change in wire distribution in steel fibre-concrete structure. Test is characterized as a so called local- failure- test using a small diameter core drill. In this sense it is a semi-destructive method.
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NÁVRH NDT METODY PRO HODNOCENÍ DRÁTKOBETONU / DESIGN OF NON-DESTRUCTIVE METHOD FOR TESTING OF STEEL FIBER REINFORCED CONCRETEKomárková, Tereza January 2019 (has links)
The doctoral thesis deals with a non-destructive testing method (NDT) designed to evaluate the uniformity of distribution and determination of the concentration of steel fibres in steel fiber reinforced concrete (SFRC). At present, no non-destructive method is available in the field of diagnostics of building structures to assess the concentration and the homogeneity of SFRC. The Institute of Building Testing (SZK FAST BUT Brno) has several diagnostic devices, but their utility for the evaluation of selected parameters of SFRC has not proven during the research activity. This knowledge led to the design of a new measuring instrument in cooperation with the Institute of Theoretical and Experimental Electrical Engineering of the Faculty of Electrical Engineering and Communication (UTEE FEKT BUT in Brno) and the methodology for evaluation of these parameters. The proposed NDT method has been experimentally tested and verified for its utility for the evaluation of SFRC in building practice.
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Návrh a realizace plošného měření rezistivity půdy / Design and implementation of the soil resistivity measurement systemDirbák, Štefan January 2020 (has links)
This diploma thesis deals with research and study of soil impedance measurement and soil resistivity. Currently, the issue of measuring and determining soil resistance is ensured through the gradual measurement of certain soil parameters at individual points of the surface (or depth of the ground). This thesis focuses on the idea of measuring soil resistance on a certain area using a network of electrodes through a suitably designed test, measurement and evaluation system. Such an approach may find application in the need to determine soil parameters (such as resistivity) on a specific demarcated area (or depth). The prospect of such an application can be seen in saving time, energy and money needed to measure the soil resistivity of a certain area (as opposed to gradual point measurements). The configuration possibilities of OMICRON CPC 100 measuring instrument were used for the design and implementation of the measuring system for the mentioned purpose. The work is completed by verification of the proposed solution by real measurement with evaluation of the results.
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Risiken des Klimawandels für den Wasserhaushalt - Variabilität und Trend des zeitlichen NiederschlagsspektrumsFranke, Johannes 01 October 2009 (has links)
Die vorliegende Arbeit wurde auf der Grundlage begutachteter Publikationen als kumulative Dissertation verfasst. Ziel war hier, das zeitliche Spektrum des Niederschlages unter sich bereits geänderten und zukünftig möglichen Klimabedingungen zu untersuchen, um daraus risikobehaftete Auswirkungen auf den Wasserhaushalt ableiten zu können. Ausgehend von den für Sachsen bzw. Mitteldeutschland jahreszeitlich berechneten Trends für den Niederschlag im Zeitraum 1951-2000 wurde hier der Schwerpunkt auf das Verhalten des Starkniederschlages im Einzugsgebiet der Weißeritz (Osterzgebirge) während der Vegetationsperiode gesetzt. Unter Verwendung von Extremwertverteilungen wurde das lokale Starkniederschlagsgeschehen im Referenzzeitraum 1961-2000 für Ereignisandauern von 1-24 Stunden und deren Wiederkehrzeiten von 5-100 Jahren aus statistischer Sicht beschrieben. Mittels eines wetterlagenbasierten statistischen Downscaling wurden mögliche Änderungen im Niveau des zeitlich höher aufgelösten Niederschlagspektrums gegenüber dem Referenzspektrum auf die Zeitscheiben um 2025 (2011-2040) und 2050 (2036-2065) projiziert. Hierfür wurden die zu erwartenden Klimabedingungen für das IPCC-Emissionsszenario A1B angenommen. Mittels eines problemangepassten Regionalisierungsalgorithmus´ konnte eine Transformation der Punktinformationen in eine stetige Flächeninformation erreicht werden. Dabei wurden verteilungsrelevante Orografieeffekte auf den Niederschlag maßstabsgerecht berücksichtigt.
Die signifikanten Niederschlagsabnahmen im Sommer bzw. in der Vegetationsperiode sind in Sachsen mit einer Zunahme und Intensivierung von Starkniederschlägen kombiniert. Hieraus entsteht ein Konfliktpotenzial zwischen Hochwasserschutz auf der einen und (Trink-) Wasserversorgung auf der anderen Seite. Für die zu erwartenden Klimabedingungen der Zeitscheiben um 2025 und 2050 wurden für das Einzugsgebiet der Weißeritz zunehmend positive, nicht-lineare Niveauverschiebungen im zeitlich höher aufgelösten Spektrum des Starkniederschlages berechnet. Für gleich bleibende Wiederkehrzeiten ergaben sich größere Regenhöhen bzw. für konstant gehaltene Regenhöhen kleinere Wiederkehrzeiten. Aus dem erhaltenen Änderungssignal kann gefolgert werden, dass der sich fortsetzende allgemeine Erwärmungstrend mit einer Intensivierung des primär thermisch induzierten, konvektiven Starkniederschlagsgeschehens einhergeht, was in Sachsen mit einem zunehmend häufigeren Auftreten von Starkregenereignissen kürzerer Andauer sowie mit einer zusätzlichen orografischen Verstärkung von Ereignissen längerer Andauer verbunden ist.
Anhand des Klimaquotienten nach Ellenberg wurden Effekte des rezenten Klimatrends auf die Verteilung der potenziellen natürlichen Vegetation in Mitteldeutschland beispielhaft untersucht. Über eine Korrektur der Berechnungsvorschrift konnte eine Berücksichtigung der trendbehafteten klimatologischen Rahmenbedingungen, insbesondere dem negativen Niederschlagstrend im Sommer, erreicht werden.
Insgesamt konnte festgestellt werden, dass die regionalen Auswirkungen des globalen Klimawandels massive Änderungen in der raum-zeitlichen Struktur des Niederschlages in Sachsen zur Folge haben, was unvermeidlich eine komplexe Wirkungskette auf den regionalen Wasserhaushalt zur Folge hat und mit Risiken verbunden ist. / This paper was written as a cumulative doctoral thesis based on appraised publications. Its objective was to study the temporal spectrum of precipitation under already changed or possible future climate conditions in order to derive effects on the water budget which are fraught with risks. Based on seasonal trends as established for Saxony and Central Germany for precipitation in the period of 1951-2000, the focus was on the behaviour of heavy precipitation in the catchment area of the Weißeritz (eastern Ore Mountains) during the growing season. Using distributions of extreme values, the local heavy precipitation behaviour in the reference period of 1961-2000 was described from a statistical point of view for event durations of 1-24 hours and their return periods of 5-100 years. Statistical downscaling based on weather patterns was used to project possible changes in the level of the high temporal resolution spectrum of precipitation, compared with the reference spectrum, to the time slices around 2025 (2011-2040) and 2050 (2036-2065). The IPCC A1B emission scenario was assumed for expected climate conditions for this purpose. Using a regionalisation algorithm adapted to the problem made it possible to achieve a transformation of local information into areal information. In doing so, distribution-relevant orographic effects on precipitation were taken into consideration in a manner true to scale.
Significant decreases in precipitation in summer and during the growing season are combined with an increase and intensification of heavy precipitation in Saxony. This gives rise to a potential for conflict between the need for flood protection, on the one hand, and the supply of (drinking) water, on the other hand. For the expected climate conditions of the time slices around 2025 and 2050, increasingly positive, non-linear shifts in the level of the high temporal resolution spectrum of heavy precipitation were calculated for the catchment of the Weißeritz. Higher amounts of rain were found if the return periods were kept constant, and shorter return periods were found if the rain amounts were kept constant. It may be concluded from the change signal obtained that the continuing general warming trend is accompanied by an intensification of the primarily thermally induced convective behaviour of heavy precipitation. In Saxony, this is associated with an increasingly frequent occurrence of heavy precipitation events of short duration and with an additional orographic intensification of events of long duration.
Using the Ellenberg climate quotient, effects of the recent climate trend on the distribution of potential natural vegetation in Central Germany were studied by way of example. Underlying climatological conditions subject to a trend, in particular the negative trend of precipitation in summer, were taken into consideration by a modification of the calculation rule.
All in all, it was found that regional effects of global climate change bring about massive changes in the spatiotemporal structure of precipitation in Saxony, which inevitably leads to a complex chain of impact on the regional water budget and is fraught with risks.
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Risiken des Klimawandels für den Wasserhaushalt – Variabilität und Trend des zeitlichen NiederschlagsspektrumsFranke, Johannes 01 October 2009 (has links)
Die vorliegende Arbeit wurde auf der Grundlage begutachteter Publikationen als kumulative Dissertation verfasst. Ziel war hier, das zeitliche Spektrum des Niederschlages unter sich bereits geänderten und zukünftig möglichen Klimabedingungen zu untersuchen, um daraus risikobehaftete Auswirkungen auf den Wasserhaushalt ableiten zu können. Ausgehend von den für Sachsen bzw. Mitteldeutschland jahreszeitlich berechneten Trends für den Niederschlag im Zeitraum 1951-2000 wurde hier der Schwerpunkt auf das Verhalten des Starkniederschlages im Einzugsgebiet der Weißeritz (Osterzgebirge) während der Vegetationsperiode gesetzt. Unter Verwendung von Extremwertverteilungen wurde das lokale Starkniederschlagsgeschehen im Referenzzeitraum 1961-2000 für Ereignisandauern von 1-24 Stunden und deren Wiederkehrzeiten von 5-100 Jahren aus statistischer Sicht beschrieben. Mittels eines wetterlagenbasierten statistischen Downscaling wurden mögliche Änderungen im Niveau des zeitlich höher aufgelösten Niederschlagspektrums gegenüber dem Referenzspektrum auf die Zeitscheiben um 2025 (2011-2040) und 2050 (2036-2065) projiziert. Hierfür wurden die zu erwartenden Klimabedingungen für das IPCC-Emissionsszenario A1B angenommen. Mittels eines problemangepassten Regionalisierungsalgorithmus´ konnte eine Transformation der Punktinformationen in eine stetige Flächeninformation erreicht werden. Dabei wurden verteilungsrelevante Orografieeffekte auf den Niederschlag maßstabsgerecht berücksichtigt.
Die signifikanten Niederschlagsabnahmen im Sommer bzw. in der Vegetationsperiode sind in Sachsen mit einer Zunahme und Intensivierung von Starkniederschlägen kombiniert. Hieraus entsteht ein Konfliktpotenzial zwischen Hochwasserschutz auf der einen und (Trink-) Wasserversorgung auf der anderen Seite. Für die zu erwartenden Klimabedingungen der Zeitscheiben um 2025 und 2050 wurden für das Einzugsgebiet der Weißeritz zunehmend positive, nicht-lineare Niveauverschiebungen im zeitlich höher aufgelösten Spektrum des Starkniederschlages berechnet. Für gleich bleibende Wiederkehrzeiten ergaben sich größere Regenhöhen bzw. für konstant gehaltene Regenhöhen kleinere Wiederkehrzeiten. Aus dem erhaltenen Änderungssignal kann gefolgert werden, dass der sich fortsetzende allgemeine Erwärmungstrend mit einer Intensivierung des primär thermisch induzierten, konvektiven Starkniederschlagsgeschehens einhergeht, was in Sachsen mit einem zunehmend häufigeren Auftreten von Starkregenereignissen kürzerer Andauer sowie mit einer zusätzlichen orografischen Verstärkung von Ereignissen längerer Andauer verbunden ist.
Anhand des Klimaquotienten nach Ellenberg wurden Effekte des rezenten Klimatrends auf die Verteilung der potenziellen natürlichen Vegetation in Mitteldeutschland beispielhaft untersucht. Über eine Korrektur der Berechnungsvorschrift konnte eine Berücksichtigung der trendbehafteten klimatologischen Rahmenbedingungen, insbesondere dem negativen Niederschlagstrend im Sommer, erreicht werden.
Insgesamt konnte festgestellt werden, dass die regionalen Auswirkungen des globalen Klimawandels massive Änderungen in der raum-zeitlichen Struktur des Niederschlages in Sachsen zur Folge haben, was unvermeidlich eine komplexe Wirkungskette auf den regionalen Wasserhaushalt zur Folge hat und mit Risiken verbunden ist. / This paper was written as a cumulative doctoral thesis based on appraised publications. Its objective was to study the temporal spectrum of precipitation under already changed or possible future climate conditions in order to derive effects on the water budget which are fraught with risks. Based on seasonal trends as established for Saxony and Central Germany for precipitation in the period of 1951-2000, the focus was on the behaviour of heavy precipitation in the catchment area of the Weißeritz (eastern Ore Mountains) during the growing season. Using distributions of extreme values, the local heavy precipitation behaviour in the reference period of 1961-2000 was described from a statistical point of view for event durations of 1-24 hours and their return periods of 5-100 years. Statistical downscaling based on weather patterns was used to project possible changes in the level of the high temporal resolution spectrum of precipitation, compared with the reference spectrum, to the time slices around 2025 (2011-2040) and 2050 (2036-2065). The IPCC A1B emission scenario was assumed for expected climate conditions for this purpose. Using a regionalisation algorithm adapted to the problem made it possible to achieve a transformation of local information into areal information. In doing so, distribution-relevant orographic effects on precipitation were taken into consideration in a manner true to scale.
Significant decreases in precipitation in summer and during the growing season are combined with an increase and intensification of heavy precipitation in Saxony. This gives rise to a potential for conflict between the need for flood protection, on the one hand, and the supply of (drinking) water, on the other hand. For the expected climate conditions of the time slices around 2025 and 2050, increasingly positive, non-linear shifts in the level of the high temporal resolution spectrum of heavy precipitation were calculated for the catchment of the Weißeritz. Higher amounts of rain were found if the return periods were kept constant, and shorter return periods were found if the rain amounts were kept constant. It may be concluded from the change signal obtained that the continuing general warming trend is accompanied by an intensification of the primarily thermally induced convective behaviour of heavy precipitation. In Saxony, this is associated with an increasingly frequent occurrence of heavy precipitation events of short duration and with an additional orographic intensification of events of long duration.
Using the Ellenberg climate quotient, effects of the recent climate trend on the distribution of potential natural vegetation in Central Germany were studied by way of example. Underlying climatological conditions subject to a trend, in particular the negative trend of precipitation in summer, were taken into consideration by a modification of the calculation rule.
All in all, it was found that regional effects of global climate change bring about massive changes in the spatiotemporal structure of precipitation in Saxony, which inevitably leads to a complex chain of impact on the regional water budget and is fraught with risks.
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